Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
  • B29B17/00—Recovery of plastics or other constituents of waste material containing plastics
  • B29B17/04—Disintegrating plastics, e.g. by milling
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B27/00—Layered products comprising a layer of synthetic resin
  • B32B27/28—Layered products comprising a layer of synthetic resin comprising synthetic resins not wholly covered by any one of the sub-groups B32B27/30 - B32B27/42
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B27/00—Layered products comprising a layer of synthetic resin
  • B32B27/30—Layered products comprising a layer of synthetic resin comprising vinyl (co)polymers; comprising acrylic (co)polymers
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B27/00—Layered products comprising a layer of synthetic resin
  • B32B27/32—Layered products comprising a layer of synthetic resin comprising polyolefins
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B9/00—Layered products comprising a layer of a particular substance not covered by groups B32B11/00 - B32B29/00
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
  • B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
  • B65D65/00—Wrappers or flexible covers; Packaging materials of special type or form
  • B65D65/38—Packaging materials of special type or form
  • B65D65/40—Applications of laminates for particular packaging purposes

Definitions

• the present invention relates to a multilayer structure comprising a vapor-deposited film including a vinyl alcohol-based polymer layer and a vapor-deposited layer.
• the present invention also relates to a packaging material comprising the multilayer structure.
• the present invention also relates to a package in which contents are housed in the packaging material.
• the present invention also relates to a recovered composition comprising recovered material from the multilayer structure.
• the present invention also relates to a method for recovering the multilayer structure.
• Packaging materials for long-term food storage often require gas barrier properties, including oxygen barrier properties.
• gas barrier properties including oxygen barrier properties.
• Using packaging materials with high gas barrier properties can prevent oxidative deterioration of food caused by oxygen penetration and the growth of microorganisms.
• Metal foils such as aluminum, metal vapor deposition layers, and inorganic oxide vapor deposition layers such as silicon oxide and aluminum oxide are widely used as inorganic layers to improve gas barrier properties (Patent Document 1).
• recycling post-consumer recycling
• recycling typically involves shredding recovered packaging materials, separating and cleaning them as necessary, and then melt-mixing them using an extruder.
• packaging materials are required to be composed of as few materials as possible (mono-materialization), which allows for the production of high-purity, high-quality recycled raw materials.
• aluminum foil and polyester film are known to hinder recyclability due to their poor compatibility and dispersibility with polyolefin-based resins, which are widely used as packaging materials.
• Patent Document 2 proposes a vapor-deposited multilayer film in which an inorganic vapor-deposited layer is laminated on the EVOH layer of a polyethylene-based multilayer film, the outermost layer of which is an EVOH layer, thereby achieving both gas barrier properties and recyclability.
• an object of the present invention is to provide a multilayer structure, and a packaging material and package using the same, which is a vapor-deposited film having an inorganic layer on the surface of a vinyl alcohol-based polymer layer, and which can suppress deterioration in gas barrier properties even when the film is bent or when it is stored for a certain period of time while being packaged with contents containing specific amounts of moisture or oil.
• Another object of the present invention is to provide a recovered composition containing recovered material from the multilayer structure, and a method for recovering the multilayer structure.
• the inventors discovered that it is possible to (1) use a vinyl alcohol polymer layer as the substrate on which the vapor-deposited layer is formed, (2) form a vapor-deposited layer made of silicon oxide or metal oxide, and (3) blow in an appropriate amount of oxygen gas when forming the vapor-deposited layer, thereby appropriately segregating oxygen elements in the vapor-deposited layer, thereby obtaining a multilayer structure that has excellent gas barrier properties, flex resistance, and storage stability when packaged with contents containing specific amounts of moisture, oil, etc., and thus completed the present invention.
• a multilayer structure comprising 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), laminated together, a vapor-deposited layer (B) having a thickness of 30 nm or more and 200 nm or less is formed directly on the surface of the vinyl alcohol polymer layer (A),
• elemental analysis of the vapor-deposited layer (B) in the depth direction from the surface (b2) to the surface (b1) of the vapor-deposited layer (B) on the vinyl alcohol polymer layer (A) side is performed using a scanning X-ray photoelectron spectrometer, 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 the surface (b1) to the molar ratio (O/M
• the polyolefin substrate layer (G), the polyolefin adhesive layer (H), and the vinyl alcohol polymer layer (A) are co-extruded.
• a packaging material comprising the multilayer structure according to any one of [1] to [14].
• a package comprising the packaging material according to [15] containing contents, The package, wherein the contents contain 5% by mass or more of moisture 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 recycled composition comprising recycled material from the multilayer structure according to any one of [1] to [14].
• a method for recovering a multilayer structure comprising crushing the multilayer structure according to any one of [1] to [14] and then melt-molding the crushed multilayer structure.
• the multilayer structure of the present invention has 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 also excellent barrier stability when packaged with contents containing specific amounts of moisture, oil, etc., providing a multilayer structure with excellent storage stability for the contents. Therefore, the multilayer structure of the present invention is suitable as a packaging material for packaging foods, etc. Furthermore, the multilayer structure of the present invention can be easily recovered and melt-molded again.
• 1 is a graph plotting the molar ratios of silicon (Si), oxygen (O), and carbon (C) (total 100 mol%) versus sputtering time when the vapor deposition layer (B) described in Example 2 was analyzed using a scanning X-ray photoelectron spectrometer.
• 2 is a graph in which the molar ratio (O/Si) calculated from FIG. 1 is plotted against the sputtering time.
• 1 is a graph plotting the molar ratios of silicon (Si), oxygen (O), and carbon (C) (total 100 mol%) versus sputtering time when the vapor deposition layer (B) described in Comparative Example 5 was analyzed using a scanning X-ray photoelectron spectrometer.
• 4 is a graph in which the molar ratio (O/Si) calculated from FIG. 3 is plotted against the sputtering time.
• gas barrier properties means the ability to barrier gases other than water vapor, unless otherwise specified.
• barrier properties 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” is sometimes expressed as "flex resistance.”
• flex resistance when describing a layer structure, "/" indicates that the layers are directly laminated, and “//" indicates that the layers are laminated directly or via an adhesive layer.
• the term “outermost layer” does not refer to a layer present only on the front side, with a distinction between the front and back sides.
• a vapor-deposited film or multilayer structure consisting of two or more layers has two outermost layers, one on one side and one on the other side.
• the inner outermost layer is sometimes referred to as the innermost layer
• the outer outermost layer is sometimes referred to as the outermost layer.
• Major component refers to the component that is contained in the greatest amount by mass.
• the "thickness” of a layer or film refers to the average value of thicknesses measured at any five points.
• the vapor-deposited film of the present invention is a vapor-deposited film (X) comprising a vinyl alcohol-based polymer layer (A) and a vapor-deposited layer (B) made of silicon oxide or a metal oxide, a vapor-deposited layer (B) having a thickness of 30 nm or more and 200 nm or less is formed directly on the surface of the vinyl alcohol polymer layer (A),
• the vapor-deposited film (X) is such that, when the surface of the vapor-deposited layer (B) facing the vinyl alcohol polymer layer (A) is designated as surface (b1) and the surface opposite to the vapor-deposited layer (B) is designated as surface (b2), and 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 spectrometer, the ratio [(O/M)b1/(O/M)c] of the molar ratio (O/M) b1 of oxygen element
• the vapor-deposited film (X) of the present invention has excellent gas barrier properties and flex resistance. While the reason for this is unclear, the following is presumed to be the case.
• oxygen atoms segregate near the interface between the vinyl alcohol-based polymer layer (A) and the vapor-deposited layer (B), presumably increasing the adhesive strength between the vinyl alcohol-based polymer layer (A) and the vapor-deposited layer (B).
• the vinyl alcohol-based polymer layer (A) maintains strong adhesiveness with the vapor-deposited layer (B), thereby preventing a decrease in gas barrier properties after the flexing treatment.
• the vinyl alcohol-based polymer layer (A) maintains strong adhesiveness with the vapor-deposited layer (B), thereby preventing deterioration of the contents.
• the vinyl alcohol polymer layer (A) contains a vinyl alcohol polymer as a main component.
• the vinyl alcohol polymer may be any polymer containing a vinyl alcohol unit, and may be polyvinyl alcohol (hereinafter sometimes referred to as PVOH) or an ethylene-vinyl alcohol copolymer (hereinafter sometimes referred to as EVOH). If the vinyl alcohol polymer layer (A) is formed by melt molding, an ethylene-vinyl alcohol copolymer is suitable.
• PVOH is a polymer that contains vinyl alcohol units as monomer units. PVOH is usually obtained by saponifying polyvinyl ester.
• the lower limit of the proportion of vinyl alcohol units relative to all monomer units in PVOH is preferably 50 mol%, more preferably 60 mol%, and even more preferably 70 mol%. By ensuring that the proportion of vinyl alcohol units is above this lower limit, good water solubility and other properties are exhibited.
• the upper limit of the proportion of vinyl alcohol units may be 100 mol%, but is preferably 99.99 mol%, and more preferably 99 mol%.
• the lower limit of the saponification degree of PVOH is preferably 35 mol%, more preferably 50 mol%, even more preferably 70 mol%, and particularly preferably 75 mol%.
• the upper limit of the saponification degree may be 100 mol%, but is preferably 99 mol%, more preferably 95 mol%, even more preferably 92 mol%, and in some cases is particularly preferably less than 88 mol%.
• the average degree of polymerization of PVOH is not particularly limited, but is preferably 200 or more, more preferably 400 or more, even more preferably 600 or more, and particularly preferably 800 or more.
• the average degree of polymerization is preferably 5,000 or less, more preferably 4,000 or less, and even more preferably 3,000 or less.
• EVOH is typically obtained by saponifying a copolymer of ethylene and a vinyl ester such as vinyl acetate, vinyl formate, vinyl propionate, vinyl valerate, vinyl caprate, vinyl laurate, vinyl stearate, vinyl pivalate, or vinyl versatate.
• the production and saponification of the copolymer of ethylene and a vinyl ester can be carried out by known methods.
• the saponification degree 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.
• a saponification degree of 90 mol% or more can enhance gas barrier properties.
• the saponification degree of the ethylene-vinyl alcohol copolymer may be 100 mol% or less or 99.99 mol% or less.
• the saponification degree of the ethylene-vinyl alcohol copolymer can be determined by nuclear magnetic resonance ( 1 H-NMR) measurement, measuring the peak area of hydrogen atoms contained in the vinyl ester structure and the peak area of hydrogen atoms contained in the vinyl alcohol structure.
• 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. An ethylene unit content of 10 mol% or more tends to maintain good gas barrier properties and flex resistance under high humidity conditions. On the other hand, an ethylene unit content of 65 mol% or less can improve gas barrier properties.
• the ethylene unit content of the ethylene-vinyl alcohol copolymer can be determined by NMR.
• 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.
• 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 may be 1 mol% or more.
• the vinyl alcohol-based polymer may contain units derived from other monomers other than ethylene, vinyl esters, and saponified products thereof, to the extent that the objectives of the present invention are not impaired.
• the content of such other monomer units relative to the total monomer units of the vinyl alcohol-based 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.
• the lower limit may be 0.05 mol% or 0.10 mol%.
• Examples of the other monomers include alkenes such as propylene, butylene, pentene, and hexene; 3-acyloxy-1-propene, 3-acyloxy-1-butene, 4-acyloxy-1-butene, 3,4-diacyloxy-1-butene, 3-acyloxy-4-methyl-1-butene, 4-acyloxy-2-methyl-1-butene, and 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-methylenepentene
• Examples include alkenes having an ester group such as propane or saponified products thereof; uns
• the average ethylene unit content or saponification degree of the entire vinyl alcohol polymer shall be taken as the ethylene unit content or saponification degree of the vinyl alcohol polymer.
• the MFR (190°C, 2.16 kg load) of the vinyl alcohol polymer is preferably 0.5 g/10 min or more and 12 g/10 min or less, and more preferably 1.0 g/10 min or more and 8.0 g/10 min or less.
• the average degree of polymerization of the vinyl alcohol polymer is preferably 200 or more and 5000 or less.
• the lower limit of the proportion of the vinyl alcohol polymer in the resin constituting the vinyl alcohol polymer layer (A) is preferably 70% by mass, more preferably 80% by mass, and even more preferably 90% by mass, from the viewpoint of gas barrier properties, etc., and may be 95%, 99%, or 99.9% by mass, or even 100% by mass.
• the lower limit of the content of the vinyl alcohol-based polymer in the vinyl alcohol-based polymer layer (A) is preferably 70% by mass, more preferably 80% by mass, and even more preferably 90% by mass, and may be 95%, 99%, or 99.9% by mass.
• the upper limit of the content of the vinyl alcohol-based polymer in the vinyl alcohol-based polymer layer (A) may be 100% by mass or 99.99% by mass.
• the vinyl alcohol polymer layer (A) may contain inorganic oxide particles as needed.
• the inorganic oxide constituting the inorganic oxide particles is 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, with silicon oxide being more preferred.
• the lower limit of the content of inorganic oxide particles 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 content of inorganic oxide particles is preferably 1% by mass, more preferably 0.7% by mass, and even more preferably 0.5% by mass. Having the content of inorganic oxide particles within the above range tends to further improve gas barrier properties.
• the average particle size of the inorganic oxide particles is preferably 1 ⁇ m or more and 10 ⁇ m or less, and more preferably 2 ⁇ m or more and 5 ⁇ m or less. Having an average particle size of the inorganic oxide particles within the above range tends to further improve gas barrier properties.
• the average particle size of the inorganic oxide particles is the d50 value measured by laser diffraction scattering.
• 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.
• the vinyl alcohol-based polymer layer (A) When the vinyl alcohol-based polymer layer (A) is formed by melt molding, the vinyl alcohol-based polymer layer (A) may be either an unstretched layer or a stretched layer. However, from the viewpoints of dimensional stability and gas barrier properties, a layer that is stretched at least uniaxially is preferred, and a layer that is stretched biaxially is even more preferred. From the viewpoints of thickness uniformity, barrier properties, mechanical properties, and film-formability, the stretching ratio is preferably 2.5 to 4.5 times in the machine direction (MD direction), 2.5 to 4.5 times in the transverse direction (TD direction), and an areal stretching ratio of 7 to 15 times, and more preferably 2.5 to 3.5 times in the machine direction, 2.5 to 3.5 times in the transverse direction, and an areal stretching ratio of 8 to 12 times. Such stretching can be carried out according to known methods such as commonly used simultaneous biaxial stretching and sequential biaxial stretching.
• the thickness of the vinyl alcohol-based polymer layer (A) is not particularly limited, but is preferably 0.1 ⁇ m or more and 20 ⁇ m or less. A thickness of 0.1 ⁇ m or more of the vinyl alcohol-based polymer layer (A) improves the gas barrier properties of the vapor-deposited film.
• the thickness of the vinyl alcohol-based polymer layer (A) is more preferably 0.2 ⁇ m or more, and even more preferably 0.5 ⁇ m or more.
• the vinyl alcohol-based polymer layer (A) can also be formed by coating a vinyl alcohol-based polymer solution onto another resin. Alternatively, the vinyl alcohol-based polymer can be co-extruded with another resin to form a multilayer film, and then stretched as needed to form the vinyl alcohol-based polymer layer (A).
• a thickness of 20 ⁇ m or less of the vinyl alcohol-based polymer layer (A) facilitates the recycled multilayer structure by mixing it with polyolefin, melt-kneading it, and reusing it, resulting in excellent recyclability.
• the thickness of the vinyl alcohol polymer layer (A) is more preferably 10 ⁇ m or less, even more preferably 8 ⁇ m or less, and particularly preferably 6 ⁇ m or less.
• the "thickness" refers to the average value of values measured at any five points, and this also applies to the thicknesses of the other layers described in this specification.
• the ratio of the thickness of the vinyl alcohol-based polymer layer (A) to the thickness of the multilayer structure is less than 25%.
• a ratio of less than 25% makes it easy to mix the recovered multilayer structure with polyolefin, melt-knead, and recover and reuse it, 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%. When particularly good recyclability is required, it is more preferably less than 10%, and even more preferably less than 5%.
• the oxygen permeability of the vinyl alcohol polymer layer (A) is preferably 50 mL 20 ⁇ m/( m2 day atm) or less, more preferably 10 mL 20 ⁇ m/( m2 day atm) or less, even more preferably 5 mL 20 ⁇ m/( m2 day atm) or less, and particularly preferably 1 mL 20 ⁇ m/( m2 day atm) or less.
• the oxygen permeability is a value measured on a 20 ⁇ m-thick film according to the method described in ISO 14663-2 Annex C (1999) under conditions of 20°C and 65% RH.
• the vapor-deposited layer (B) made of silicon oxide or a metal oxide can be effectively formed, for example, by vacuum deposition.
• the degree of segregation can be controlled by, for example, the supply rate of oxygen gas sprayed onto the resin film.
• the supply rate of oxygen gas to the resin film is preferably, for example, from 0.1 mL/min to 10 mL/min, more preferably from 0.2 mL/min to 5 mL/min, and even more preferably from 0.3 mL/min to 1 mL/min.
• the appropriate supply rate of oxygen gas can be appropriately adjusted depending on conditions such as the deposition rate of silicon oxide or a metal oxide.
• the vapor-deposited layer (B) with segregated oxygen elements may also be formed by a vapor deposition method other than those described above.
• the vapor deposition layer (B) may be provided by sputtering, ion plating, ion beam mixing, plasma CVD, laser CVD, MO-CVD, thermal CVD, or the like.
• the surface of the vinyl alcohol polymer layer (A) to be vapor-deposited may be plasma-treated.
• Known methods can be used for the plasma treatment, with atmospheric pressure plasma treatment being preferred.
• discharge gases used in atmospheric pressure plasma treatment include nitrogen gas, helium, neon, argon, krypton, xenon, and radon.
• the vapor-deposited layer (B) made of silicon oxide or a metal oxide (MO x ) is made of silicon oxide (SiO x ) or a metal oxide.
• M represents silicon or a metal element.
• metal oxides include aluminum oxide (AlO x ), 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.
• the vapor-deposited film (X) of the present invention is most characterized in that, when elemental analysis of the vapor-deposited layer (B) in the depth direction from the surface (b2) to the surface (b1) of the vapor-deposited layer (B) facing the ethylene-vinyl alcohol copolymer layer (A) is performed using a scanning X-ray photoelectron spectrometer, the ratio [(O/M)b1/(O/M)c] of the molar ratio (O/M) b1 of oxygen (O) to silicon or metal element (M) in the surface (b1) to the molar ratio (O/M) c of oxygen (O) to silicon or metal element (M) at a position equidistant from the surface ( b1 ) and the surface ( b2 ) is 1.1 or more and 1.7 or less.
• Figure 1 is a graph plotting the molar ratios of silicon (Si), oxygen (O), and carbon (C) (total 100 mol%) versus sputtering time when the vapor-deposited layer (B) described in Example 2 was analyzed using a scanning X-ray photoelectron spectrometer.
• Figure 2 is a graph plotting the molar ratio (O/Si) calculated from Figure 1 versus sputtering time.
• the sputtering time of 0 minutes corresponds to the outermost surface of the vapor-deposited layer (B), which corresponds to surface (b2). Near surface (b2) exposed to the outside air, C and O increase due to the adsorption and oxidation of organic substances. Meanwhile, the composition of the vapor-deposited layer (B) near surface (b1) in contact with the vinyl alcohol-based polymer layer (A) also becomes unstable due to the influence of the vinyl alcohol-based polymer layer (A). Therefore, the molar ratio (O/M) c at a position (center) equidistant from the surface (b1) and the surface (b2) was used as the reference value.
• the "position equidistant from the surface (b1) and the surface (b2)" corresponds to half of the sputtering time of the surface (b1).
• the surface (b1) corresponds to the time when the proportion of carbon elements derived from the vinyl alcohol-based polymer layer (A) reaches 1 mol %, indicating the point at which the influence of the substrate begins.
• the vapor-deposited film described in Example 2 was characterized by an increase in the oxygen concentration in the vapor-deposited layer (B) near the surface (b1) because the film was formed while oxygen was supplied near the surface of the vinyl alcohol-based polymer layer (A) of the substrate.
• a large ratio [(O/M) b1 /(O/M) c ] means that the oxygen content in the vapor-deposited layer (B) is high near the interface between the vinyl alcohol-based polymer layer (A) and the vapor-deposited layer (B), which is presumed to improve the adhesion between the vinyl alcohol-based polymer layer (A) and the vapor-deposited layer (B) and make the gas barrier property less likely to deteriorate even after bending treatment.
• the ratio [(O/M) b1 /(O/M) c ] is less than 1.1 and the gas barrier property after bending treatment is insufficient. This also suggests that the presence of oxygen near the interface with the substrate changes depending on the substrate, resulting in a change in the degree of oxidation of the vapor-deposited layer (B).
• the ratio [(O/M) b1 /(O/M) c ] is preferably 1.13 or more, more preferably 1.15 or more.
• the vapor deposition layer (B) can suppress a decrease in gas barrier properties after a storage test.
• the ratio [(O/M) b1 /(O/M) c ] is preferably 1.5 or less, more preferably 1.3 or less.
• the molar ratio (O/M) b1 of oxygen (O) to silicon or metal (M) in the surface (b1) is preferably 1.85 or more and 2.35 or less.
• the molar ratio (O/M) b1 is more preferably 1.95 or more, even more preferably 2.0 or more, and particularly preferably 2.05 or more.
• a homogeneous vapor-deposited layer (B) can be formed.
• the molar ratio (O/M) b1 is more preferably 2.3 or less.
• the molar ratio (O/M) c of oxygen (O) to silicon or metal (M) at a position equidistant from the surface (b1) and the surface (b2) is preferably 1.5 or more and 2.0 or less.
• the vapor deposition layer (B) can suppress a decrease in gas barrier properties after a storage test.
• the molar ratio (O/M) c is more preferably 1.55 or more, even more preferably 1.6 or more, and particularly preferably 1.65 or more, and in some cases 1.80 or more is preferable, and in other cases 1.81 or more is preferable.
• the molar ratio (O/M) c is 2.0 or less, the difference with (O/M) b1 can be easily increased.
• the molar ratio (O/M) c is more preferably 1.95 or less, and even more preferably 1.9 or less.
• 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, more preferably 50 nm.
• the upper limit of the thickness of the vapor-deposited layer (B) is preferably 180 nm, and may be 160 nm or 140 nm.
• 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 ⁇ m, 8 ⁇ m, or 10 ⁇ m. On the other hand, the upper limit may be, for example, 100 ⁇ m, 50 ⁇ m, 30 ⁇ m, or 20 ⁇ m.
• the oxygen permeability of the vapor-deposited film (X) of the present invention is preferably less than 1.0 mL/( m2 ⁇ day ⁇ atm), more preferably less than 0.10 mL/( m2 ⁇ day ⁇ atm), even more preferably less than 0.08 mL/( m2 ⁇ day ⁇ atm), and particularly preferably less than 0.05 mL/( m2 ⁇ day ⁇ atm).
• An oxygen permeability below the above upper limit makes the film particularly suitable for use as various packaging materials, etc.
• the lower limit of the oxygen permeability may be 0 mL/( m2 ⁇ day ⁇ atm) or 0.001 mL/( m2 ⁇ day ⁇ atm).
• the oxygen permeability of the vapor-deposited film (X) is a value measured in accordance with the method described in ISO 14663-2 Annex C (1999) under conditions of 20°C and 65% RH.
• the vapor-deposited film (X) comprises, in this order, a polyolefin substrate layer (G), a polyolefin-based adhesive layer (H), a vinyl alcohol-based polymer layer (A), and a vapor-deposited layer (B). These layers are in direct contact with each other.
• the polyolefin substrate layer (G), the polyolefin-based adhesive layer (H), and the vinyl alcohol-based polymer layer (A) are preferably co-extruded. Co-extrusion improves productivity and makes it easier to thin the vinyl alcohol-based polymer layer (A).
• the polyolefin substrate layer (G), the polyolefin-based adhesive layer (H), and the vinyl alcohol-based polymer layer (A) are preferably stretched at least uniaxially. They are more preferably stretched biaxially.
• the stretching ratio and stretching conditions are as described above for the vinyl alcohol-based polymer layer (A). This allows the vinyl alcohol-based polymer layer (A) to be further thinned and improves its elastic modulus.
• the vinyl alcohol polymer layer (A) contain, as a main component, an ethylene-vinyl alcohol copolymer having an ethylene unit content of 10 to 65 mol% and a saponification degree of 90 mol% or more.
• An ethylene unit content of 10 mol% or more improves melt moldability.
• the ethylene unit content is more preferably 15 mol% or more, even more preferably 20 mol% or more, and particularly preferably 25 mol% or more.
• an ethylene content of 65 mol% or less improves gas barrier properties.
• the ethylene unit content is more preferably 60 mol% or less, even more preferably 55 mol% or less, and particularly preferably 50 mol% or less. Furthermore, a saponification degree of 90 mol% or more improves melt stability. The saponification degree is more preferably 95 mol% or more, even more preferably 98 mol% or more, and particularly preferably 99 mol% or more.
• 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. These layers may be in direct contact with each other, or may be formed via an adhesive layer.
• the vinyl alcohol-based polymer layer (A) is preferably formed by coating a solution or dispersion of the vinyl alcohol-based polymer onto the polyolefin substrate layer (G). This makes it easy to thin the vinyl alcohol-based polymer layer (A).
• Suitable solvents for the solution are alcohol, water, or a mixture of these. Examples of alcohols include methanol, ethanol, 1-propanol, and 2-propanol.
• Suitable dispersion media for the dispersion are water.
• the vinyl alcohol polymer layer (A) contains, as a main component, a vinyl alcohol polymer having an ethylene unit content of 50 mol% or less and a degree of saponification of 70 mol% or more.
• An ethylene unit content of 50 mol% or less improves solubility in solvents. In this case, the ethylene unit content is more preferably 40 mol% or less.
• the ethylene unit content When dissolved 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 standpoint of water solubility, it may be 1 mol% or more.
• the vapor-deposited film (X) of the present invention has excellent gas barrier properties and flex resistance. Furthermore, the vapor-deposited film (X) can suppress deterioration of gas barrier properties after a storage test. Therefore, the vapor-deposited film (X) can be used in a variety of applications. Examples of applications of 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 insulators.
• the multilayer structure of the present invention is a multilayer structure formed by laminating a vapor-deposited film (X) and a polyolefin layer (C).
• the thickness of the polyolefin-based layer accounts for 75% or more of the total thickness of the multilayer structure.
• a high polyolefin content contributes to excellent recyclability.
• the thickness of the polyolefin-based layer is preferably 85% or more, more preferably 90% or more, and particularly preferably 95% or more.
• the polyolefin-based layer may refer to not only the “polyolefin layer (C)," but also any layer containing a resin with an olefin unit content of 25 mol% or more by molar ratio, such as a "polyolefin substrate layer (G),” a “polyolefin-based adhesive layer (H),” or an EVOH layer with an ethylene unit content of 25 mol% or more.
• a layer containing a resin with an olefin unit content of 50 mol% or more by molar ratio as a main component may be used as the polyolefin-based layer.
• the multilayer structure of the present invention is a multilayer structure formed by laminating the vapor-deposited film (X) of the present invention and a polyolefin layer (C). That is, it comprises a vapor-deposited film (X) and a polyolefin layer (C) laminated directly or via another layer on at least one side of the vapor-deposited film (X).
• the multilayer structure comprises the vapor-deposited film (X) and the polyolefin layer (C)
• the polyolefin layer (C) when the polyolefin layer (C) is the outermost layer of the multilayer structure, it can be easily molded into a bag-like shape, for example, by heat-sealing the polyolefin layer (C) as a heat-sealable layer.
• the polyolefin layer (C) may be the innermost layer when formed into a bag.
• the polyolefin layer (C) may be laminated directly to the vapor-deposited film (X) of the present invention, or may be laminated via another layer.
• Examples of such another layer include an adhesive layer.
• Examples of such an adhesive layer include a layer made of a curing adhesive (such as a two-component reactive polyurethane adhesive).
• the polyolefin constituting the polyolefin layer (C) is preferably polyethylene or polypropylene.
• the polyolefin layer (C) may be an unstretched layer or a stretched layer.
• the innermost layer is a polyolefin layer (C) when formed into a bag shape, it is preferable that the innermost polyolefin layer (C) be an unstretched layer from the viewpoint of good heat sealing properties.
• the lower limit of the thickness of the polyolefin layer (C) is preferably 5 ⁇ m, more preferably 10 ⁇ m, and even more preferably 15 ⁇ m, and may be 20 ⁇ m, 30 ⁇ m, or 40 ⁇ m. Having a thickness of the polyolefin layer (C) equal to or greater than the above lower limit allows for sufficient moisture resistance, etc. Furthermore, when the polyolefin layer (C) is the outermost layer, having a thickness of the polyolefin layer (C) equal to or greater than the above lower limit also allows for sufficient heat sealability.
• the upper limit of the thickness of the polyolefin layer (C) is preferably 200 ⁇ m, more preferably 100 ⁇ m, and may be 60 ⁇ m or 40 ⁇ m. Having a thickness of the polyolefin layer (C) equal to or less than the above upper limit allows for the multilayer structure to be made thinner, etc.
• the polyolefin content in the polyolefin layer (C) is preferably 80% by mass or more and 100% by mass or less, more preferably 90% by mass or more and 100% by mass or less, and even more preferably 97% by mass or more and 100% by mass or less.
• the polyolefin layer (C) may contain components other than polyolefin, such as antioxidants, UV absorbers, plasticizers, antistatic agents, lubricants, colorants, fillers, heat stabilizers, and resins other than polyolefins.
• 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 an oriented polyolefin layer.
• the unstretched polyolefin layer has good heat sealing properties when used as a sealant layer.
• the oriented polyolefin layer has excellent rigidity and water vapor barrier properties.
• the multilayer structure of the present invention preferably does not contain a layer containing as its main component a resin with a melting point of 200°C or higher, or a metal layer with a thickness of 1 ⁇ m or more. If such a layer is contained, melt-kneading at low temperatures becomes difficult when the multilayer structure is recovered and melt-kneaded, making it difficult to recycle it together with polyolefin. Therefore, it is preferable that the multilayer structure of the present invention does not contain a polyester layer, a polyamide layer, aluminum foil, etc.
• the multilayer structure of the present invention may further include another vapor-deposited film (Y) laminated directly or via another layer to the vapor-deposited film (X) of the present invention.
• the multilayer structure of the present invention may include multiple vapor-deposited films, at least one of which may be the vapor-deposited film (X) of the present invention.
• a preferred example of the vapor-deposited film (Y) is a vapor-deposited film (Y) comprising a polyolefin layer and a vapor-deposited layer (E) composed of silicon oxide or a metal oxide.
• a biaxially oriented polypropylene layer is preferred as the polyolefin layer.
• the vapor-deposited layer (E) may be formed as a silicon oxide or aluminum oxide layer with a thickness similar to that of the vapor-deposited layer (B).
• a multilayer structure comprising multiple vapor-deposited films has superior gas barrier properties.
• the multiple vapor-deposited films may be laminated directly to each other or via another layer. An adhesive layer is preferred as the other layer. Multiple layers may be present between the multiple vapor-deposited films.
• the thickness of the adhesive layer is, for example, preferably 0.1 ⁇ m or more and 10 ⁇ m or less, more preferably 0.3 ⁇ m or more and 7 ⁇ m or less, and even more preferably 0.5 ⁇ m or more and 5 ⁇ m or less.
• a polyurethane-based adhesive is suitable as the adhesive.
• the layer structure of the multilayer structure of the present invention may be, for example, (1) Vinyl alcohol 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 etc.
• the lower limit of the thickness of the multilayer structure of the present invention (the thickness of the entire multilayer structure) is preferably 10 ⁇ m, and may be 20 ⁇ m, 30 ⁇ m, or 50 ⁇ m. When the thickness of the multilayer structure is equal to or greater than the above lower limit, the gas barrier properties and flex resistance can be further improved.
• the upper limit of the thickness of the multilayer structure is preferably 1,000 ⁇ m, and may be 500 ⁇ m, 300 ⁇ m, 200 ⁇ m, or 100 ⁇ m.
• the method for producing the multilayer structure of the present invention is not particularly limited.
• a multilayer structure can be obtained by laminating a polyolefin layer (C) or the like onto the vapor-deposited film (X) of the present invention by known means such as dry lamination.
• Applications of the multilayer structure of the present invention include various packaging materials such as food packaging, pharmaceutical packaging, industrial chemical packaging, and pesticide packaging.
• 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 may be molded into a predetermined shape such as a bag. From the viewpoint of heat sealing properties, etc., it is preferable that the polyolefin layer (C) is located in the outermost layer as a heat-sealable layer. Also, from the viewpoint of heat sealing properties, etc., it is preferable that the polyolefin layer (C) located in the outermost layer is not stretched.
• the polyolefin layer (C) is located at least in the innermost layer. Also, it is preferable that the vapor-deposited layer (B) is located outside the vinyl alcohol-based polymer layer (A).
• the packaging material of the present invention is used for packaging, for example, food, beverages, medicines, medical equipment, machine parts, clothing, etc.
• the packaging material is preferably used in applications requiring oxygen barrier properties and applications in which the interior of the packaging material is replaced with various functional gases.
• the packaging material comprises the vapor-deposited film (X) of the present invention, deterioration of gas barrier properties after bending treatment is suppressed, and high gas barrier properties can be maintained over an extended period of time.
• the packaging material is suitable as a packaging material for containing contents that contain 5% or more by mass of moisture and at least one selected from the group consisting of 1% or more by mass of lipids, 1% or more by mass of sodium chloride, and 0.5% or more by mass of acetic acid.
• the packaging material of the present invention is less likely to deteriorate in gas barrier properties even when containing such foods with high moisture contents.
• the packaging material can be formed into various forms depending on the application, such as vertical form-fill-seal bags, spouted pouches, laminated tube containers, container lids, vacuum packaging bags, etc.
• Vertical form, fill, seal bags are used to package, for example, liquids, viscous materials, powders, bulk solids, and combinations of these foods and beverages.
• Vertical form, fill, seal bags are formed by heat-sealing a multilayer structure.
• a heat-sealable layer e.g., polyolefin layer (C)
• C polyolefin layer
• the heat-sealable layer is only on the inner side of the vertical form, fill, seal bag, the body is usually sealed by seaming.
• heat-sealable layers are on both the inner and outer sides of the vertical form, fill, seal bag, the body is usually sealed by enveloping.
• Spouted pouches are used to package liquid substances, such as soft drinks and other liquid beverages, jelly drinks, yogurt, fruit sauces, seasonings, functional water, and liquid foods.
• Laminated tube containers are used to package cosmetics, medicines, pharmaceuticals, food, toothpaste, and other products.
• Container lids are used to package containers filled with processed meat products, processed vegetables, processed seafood products, fruit, and other foods.
• a vacuum packaging bag comprises a packaging bag formed from the packaging material of the present invention, and the interior of the packaging bag is decompressed.
• the vacuum bag is suitable for applications where packaging in a vacuum state is desired, such as preserving food, beverages, etc., and as an outer packaging material for vacuum insulators. Because such a vacuum packaging bag comprises the vapor-deposited film (X) of the present invention, deterioration of gas barrier properties after bending treatment is suppressed, and a high vacuum state can be maintained for an extended period of time.
• a multilayer structure suitable for use in vacuum packaging bags is preferably configured to comprise multiple vapor-deposited films (X).
• PE1 "INNATE (trademark) TF80" (manufactured by DOW, linear low-density polyethylene, MFR (190°C, 2.16 kg load) 1.6 g/10 min, melting point 124°C, density 0.926 g/cm 3 )
• MAhPP1 "Admer (trademark) QF500” (manufactured by Mitsui Chemicals, Inc., maleic anhydride modified polypropylene, MFR (230°C, 2.16 kg load) 3.0 g/10 min)
• MAhPP2 "ADMERTM SF730" (manufactured by Mitsui Chemicals, Inc., maleic anhydride-modified polyolefin, MFR (190°C, 2.16 kg load) 2.7 g/10 min)
• MAhPE1 Admer (trademark) NF518 (manufactured by Mitsui Chemicals, Inc., maleic anhydride modified polyethylene, MFR (190°C, 2.16 kg load
• the X-ray source was AlK ⁇ (1486.6 eV), the X-ray beam diameter was 100 ⁇ m ⁇ (25 W, 15 kV), the measurement range was 300 ⁇ m horizontal ⁇ 300 ⁇ m vertical, the signal acceptance angle was 45°, and the vacuum degree was 1 ⁇ 10 ⁇ 6 Pa.
• the molar ratio of oxygen (O) to silicon or metal element (M) on surface (b1) was defined as (O/M) b1
• the molar ratio of oxygen (O) to silicon or metal element (M) at a position equidistant from surface (b1) and surface (b2) was defined as (O/M) c
• the ratio [(O/M) b1 /(O/M) c ] was calculated.
• surface (b2) is the position where sputtering started
• surface (b1) is the position where the content of carbon derived from EVOH layer (A) reached 1 mol%
• the position equidistant from surface (b1) and surface (b2) was the midpoint of the etching time.
• Oxygen transmission rate The oxygen transmission rate of the multilayer structures obtained in the examples and comparative examples was measured in accordance with the method described in JIS K 7126-2 (isobaric method; 2006). Specifically, using an oxygen transmission rate measuring device ("MOCON OX-TRAN2/21" manufactured by Modern Controls), the oxygen transmission rate (unit: cc/(m2 day atm)) 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 atmosphere, and carrier gas pressure 1 atmosphere. Nitrogen gas containing 2% by volume of hydrogen gas was used as the carrier gas. The structures were arranged so that the outer layer was the oxygen supply side and the inner layer (sealant layer side) was the carrier gas side.
• Oxygen transmission rate (OTR) of the deposited film after bending test Samples measuring 20 cm x 25 cm were cut from the vapor-deposited films obtained in the Examples and Comparative Examples, and a Gelbo Flex test (flexion test) was performed in accordance with ASTM F 392 using a Gelbo Flex Tester (BE-1005) manufactured by Tester Sangyo Co., Ltd. Specifically, the cut-out vapor-deposited films were formed into cylindrical shapes with a diameter of 3.5 inches in an atmosphere of 23°C and 50% RH, and both ends were fixed to the Gelbo Flex Tester.
• OTR Oxygen transmission rate
• the sample was subjected to three cycles of reciprocating motion, with an initial spacing of 7 inches, a maximum flex spacing of 1 inch, a 440° twist in the first 3.5 inches of the stroke, and a linear horizontal motion for the subsequent 2.5 inches.
• a portion of the bent portion of the vapor-deposited film after the flexion test was cut out, and the oxygen permeability was measured according to the method described in Evaluation method (2) above.
• a vapor-deposited layer (B) made of silicon oxide was formed on the surface of the vinyl alcohol copolymer layer (A) of the obtained biaxially stretched multilayer film by the following method using a winding-type vacuum vapor deposition apparatus "EWA-105" manufactured by Japan Vacuum Engineering Co., Ltd., which has a transfer chamber and a vapor deposition chamber.
• the "EWA-105" has an unwinder and winder on the transfer chamber side, and a crucible for heating silicon oxide (SiO x ) and a cooling can for cooling the film while transporting it within the vapor deposition chamber, with the film being transported along the cooling can.
• the cooling can was cooled to -30°C, and a 20 cm wide EVOH-1 was transported at a transport speed of 150 m/min. Furthermore, a nozzle was installed in the deposition chamber to spray oxygen directly onto the EVOH-1 before deposition (nozzle gap 2 mm, film-nozzle distance 2 cm, angle to the film 30 degrees), and vacuum deposition of silicon oxide was carried out while spraying oxygen at a rate of 0.38 mL/min, to produce a deposited film in which a 40 nm-thick SiOx deposited layer (deposited layer (B)) was 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 was cut out from the obtained deposited film and evaluated according to the method described in the above evaluation method (1). The results are shown in Table 1.
• An adhesive solution was prepared by mixing 24 parts by weight of a two-component reactive polyurethane adhesive (Mitsui Chemicals, Inc.'s "TakelacTM A-520" and 4 parts by weight of "TakenateTM A-50") with 37 parts by weight of ethyl acetate.
• the adhesive solution was applied to the vapor-deposited surface of the resulting vapor-deposited film using a wire bar to a dry thickness of 2 ⁇ m.
• the resulting solution was then dried at 100°C for 5 minutes and laminated to the corona-treated side of the CPP to form the polyolefin layer (C), which served as a sealant layer.
• Examples 2 to 5, Comparative Example 1 Vapor-deposited films and multilayer structures were prepared and evaluated in the same manner as in Example 1, except that the conveying speed of the biaxially stretched multilayer film during vapor deposition was changed so that the thickness of the vapor-deposited layer (B) made of silicon oxide was 60 nm (Example 2), 80 nm (Example 3), 100 nm (Example 4), 120 nm (Example 5), or 20 nm (Comparative Example 1). The results are shown in Table 1.
• the molar ratios of silicon (Si), oxygen (O), and carbon (C) (total: 100 mol%) versus sputtering time are plotted in FIG. 1
• the molar ratio (O/Si) versus sputtering time is plotted in FIG. 2 .
• Carbon derived from organic contamination on the vapor-deposited film surface was detected on surface (b2) at the start of sputtering, but carbon was no longer detected after etching proceeded for about 0.5 minutes.
• carbon derived 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) b1 at this time was obtained.
• the molar ratio (O/Si) c of oxygen (O) to silicon (Si) at positions equidistant from the surface (b1) and the surface (b2) was measured at a sputtering time of 3.005 minutes.
• the ratio [(O/Si) b1 /(O/Si) c ] was 1.17, indicating that the molar ratio (O/Si) was higher near the interface with the EVOH layer (A) than at the center of the vapor-deposited layer (B).
• Example 7 A deposited film and a multilayer structure were prepared and evaluated in the same manner 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.
• Example 8 A deposited film was prepared and evaluated in the same manner as in Example 2, except that the supply rate of oxygen blown during deposition was changed to 0.78 mL/min. The results are shown in Table 1.
• a vapor-deposited film was produced in the same manner as in Example 1, in which a 40 nm thick SiOx vapor-deposited layer (vapor-deposited layer (B)) was formed on the surface of the vinyl alcohol copolymer layer (A) of the obtained biaxially stretched multilayer film. A portion was cut out from the obtained vapor-deposited film and evaluated according to the method described in Evaluation Method (1) above. The results are shown in Table 1.
• An adhesive solution was prepared by mixing 24 parts by weight of a two-component reactive polyurethane adhesive (Mitsui Chemicals, Inc.'s "TakelacTM A-520" and 4 parts by weight of "TakenateTM A-50") with 37 parts by weight of ethyl acetate.
• the adhesive solution was applied to the vapor-deposited surface of the resulting vapor-deposited film using a wire bar to a dry thickness of 2 ⁇ m.
• the resulting solution was then dried at 100°C for 5 minutes and laminated to the corona-treated side of the LLDPE to form the polyolefin layer (C), which served as the sealant layer.
• Example 10 Vapor-deposited films and multilayer structures were prepared and evaluated in the same manner as in Example 9, except that the conveying speed of the biaxially stretched multilayer film during vapor deposition was changed so that the thickness of the vapor-deposited layer (B) made of silicon oxide was 60 nm (Example 10), 80 nm (Example 11), 100 nm (Example 12), or 120 nm (Example 13). The results are shown in Table 1.
• Example 14 A deposited film and a multilayer structure were prepared and evaluated in the same manner 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.
• Example 15 A vapor-deposited film was produced in the same manner as in Example 1.
• An adhesive solution was prepared by mixing a two-component reactive polyurethane adhesive (24 parts by mass of "TakelacTM A-520" and 4 parts by mass of "TakenateTM A-50” manufactured by Mitsui Chemicals, Inc.) with 37 parts by mass of ethyl acetate.
• the adhesive solution was applied to the corona-treated surface of BOPP (polyolefin layer (C)) using a wire bar to a thickness of 2 ⁇ m after drying, and the applied solution was dried at 100°C for 5 minutes, followed by lamination to the vapor-deposited surface side of the resulting vapor-deposited film.
• BOPP polyolefin layer
• the adhesive solution was applied to the corona-treated surface of the CPP using a wire bar to form a polyolefin layer (C) serving as a sealant layer, so that the thickness after drying would be 2 ⁇ m.
• the applied solution was then dried at 100° C.
• the adhesion temperature (heating roll temperature) during lamination was 80° C., and after production of the multilayer structure, it was aged at 40° C. for 3 days.
• the resulting multilayer structure was evaluated according to the methods described in the above evaluation methods (2) to (4). The results are shown in Table 1.
• Example 16 A vapor-deposited film was produced in the same manner as in Example 2, except that the silicon oxide in the vapor deposition chamber was replaced with aluminum oxide (AlO x ). A portion was cut out for measuring the vapor-deposited layer. Evaluation was performed according to the method described in the above evaluation method (1). The results are shown in Table 1.
• protective layer/vapor-deposited layer (B)/vinyl alcohol-based polymer layer (A)/polyolefin-based adhesive layer (H)/polyolefin substrate layer (G) 2 ⁇ m/60 nm/2 ⁇ m/2 ⁇ m/20 ⁇ m.
• PET (Comparative Example 2) was used instead of EVOH-1, MAhPP2 instead of MAhPP1, and PP1 was used as the material for the polyolefin substrate layer (G).
• a vapor-deposited film was produced in the same manner as in Example 2 on the PET surface of the obtained biaxially stretched multilayer film, in which a 60 nm thick SiOx vapor-deposited layer (vapor-deposited layer (B)) was formed on the PET. A portion was cut out for measuring the vapor-deposited layer. Evaluation was performed according to the method described in Evaluation Method (1) above. The results are shown in Table 1.
• An adhesive solution was prepared by mixing 24 parts by weight of a two-component reactive polyurethane adhesive (Mitsui Chemicals, Inc.'s "TakelacTM A-520" and 4 parts by weight of "TakenateTM A-50") with 37 parts by weight of ethyl acetate.
• the adhesive solution was applied to the vapor-deposited surface of the resulting vapor-deposited film using a wire bar to a dry thickness of 2 ⁇ m.
• the resulting film was dried at 100°C for 5 minutes and laminated to the corona-treated side of the CPP to form a polyolefin layer (C), which served as a sealant layer.
• Comparative Example 4 A deposited film and a multilayer structure were prepared and evaluated in the same manner as in Comparative Example 2, except that the oxygen supply rate during deposition was changed to 0 mL/min. The results are shown in Table 1.
• the molar ratios of silicon, oxygen, and carbon (total: 100 mol%) were plotted against sputtering time in FIG. 3 , and the molar ratio (O/Si) at that time was plotted against sputtering time in FIG. 4 .
• Carbon derived from organic contamination on the vapor-deposited film surface was detected on surface (b2) at the start of sputtering, but carbon was no longer detected after etching proceeded for about 0.5 minutes.
• carbon derived 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 (O/Si) b1 at this time was obtained.
• the molar ratio (O/Si) c of oxygen (O) to silicon (Si) at positions equidistant from the surface (b1) and the surface (b2) was measured at a sputtering time of 3.03 minutes.
• the ratio [(O/Si) b1 /(O/Si) c ] was 1.08, indicating that the molar ratio (O/Si) near the interface with the EVOH layer (A) was smaller than in Example 2, in which oxygen was supplied during deposition.
• Example 8 A deposited film was prepared and evaluated in the same manner as in Example 2, except that the oxygen supply rate during deposition was changed to 0.10 mL/min. The results are shown in Table 1.
• Example 10 A 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 supply rate of oxygen blown during deposition was changed to 0 mL/min. The results are shown in Table 1.
• 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.
• BOPP was used as the polyolefin substrate layer (G), and the anchor coat solution was applied to the corona-treated surface of the BOPP with a wire bar to a dry thickness of 0.2 ⁇ m. The solution was then dried at 100 ° C for 5 minutes to form an anchor coat layer. The EVOH-3 aqueous solution prepared above was applied onto the anchor coat layer with a wire bar so that the thickness after drying would be 0.5 ⁇ m, and then dried at 100° C. for 5 minutes to form a barrier layer.
• a vapor-deposited film was produced in which a 60 nm thick SiOx vapor-deposited layer (vapor-deposited layer (B)) was formed on the EVOH surface of the resulting multilayer film in the same manner as in Example 2. A portion was cut out for measuring the vapor-deposited layer. Evaluation was performed according to the method described in Evaluation Method (1) above. The results are shown in Table 2.
• An adhesive solution was prepared by mixing 24 parts by weight of a two-component reactive polyurethane adhesive (Mitsui Chemicals, Inc.'s "TakelacTM A-520" and 4 parts by weight of "TakenateTM A-50") with 37 parts by weight of ethyl acetate.
• the adhesive solution was applied to the vapor-deposited surface of the resulting vapor-deposited film using a wire bar to a dry thickness of 2 ⁇ m.
• the resulting solution was then dried at 100°C for 5 minutes and laminated to the corona-treated side of the CPP to form a polyolefin layer (C), which served as a sealant layer.
• Example 18 instead of EVOH-3, PVOH-1 (Example 18) or EVOH-2 (Example 19) was used as the material for the vinyl alcohol polymer layer (A), and a vapor-deposited film and a multilayer structure were prepared and evaluated in the same manner as in Example 17.
• Example 20 The multilayer structure obtained in Example 1 was pulverized into pieces of 5 mm square or less. This pulverized material was blended with polyethylene resin (NovatecTM LD LJ400, manufactured by Japan Polyethylene Corporation; low-density polyethylene, melting point 108°C) at a mass ratio (pulverized material/polyethylene resin) of 40/60, and a single-layer film was formed under the extrusion conditions shown below to obtain a recycled composition film with a thickness of 50 ⁇ m. 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 ⁇ m was similarly obtained using only polyethylene resin.
• polyethylene resin NeovatecTM LD LJ400, manufactured by Japan Polyethylene Corporation; low-density polyethylene, melting point 108°C
• Extrusion temperature: C1/C2/C3/D 160/190/190/190°C
• Take-up roll temperature: 50°C The extrusion processability of the recovered composition was stable and good. The amount of gels and particles in the recovered composition film was almost the same as that of the polyethylene film, and the film had a uniform and good appearance except for slight discoloration.

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