JP7487456B2 - Barrier Film - Google Patents

Description

The present invention relates to a barrier film, and more specifically, to a barrier film that has a small thermal shrinkage rate measured under specific conditions.

Conventionally, packaging materials used for packaging food, daily necessities, pharmaceuticals, etc., need to prevent the contents from deteriorating and maintain their functions and properties, and must be protected from the effects of oxygen, water vapor, and other gases that degrade the contents, which permeate the packaging material. They are therefore required to have gas barrier properties to block these gases. For this reason, films of vinylidene chloride resins, which have excellent gas barrier properties among polymers, or films coated with these resins, have been commonly used. However, the gas barrier properties of these materials are significantly affected by factors such as temperature and humidity, and there has been a technical challenge in that they cannot meet the demand for high levels of gas barrier properties.

For items that require a high level of gas barrier properties, packaging materials that use metal foils made of aluminum or other metals as a gas barrier layer have been used. However, while packaging materials that use metal foils made of aluminum or other metals have high gas barrier properties and are not affected by temperature or humidity, there are technical issues with them, such as the inability to see through the packaging material to check the contents, the need to dispose of them as non-combustible waste after use, and the inability to use metal detectors during inspection.

In recent years, to solve these technical problems, vapor-deposited films, in which a vapor-deposited thin layer of inorganic oxides such as silicon oxide, aluminum oxide, and magnesium oxide is laminated on a polymer film by a forming method such as vacuum deposition or sputtering, have been used as barrier films.

However, the gas barrier properties of the above-mentioned barrier films are not necessarily sufficient, and there is a technical problem that the gas barrier properties vary. In order to solve such technical problems, a biaxially oriented polyester film for SiOx deposition has been proposed, in which the longitudinal and transverse thermal shrinkage rates under specific thermal conditions (160°C x 5 minutes) are 1.0% to 2.0% and 0.5% to 1.0%, respectively (see Patent Document 1).

JP 10-6393 A

However, even in the case of the biaxially stretched polyester film for SiOx deposition proposed in Patent Document 1, the gas barrier properties (particularly the water vapor barrier properties) of the gas barrier film having a barrier coat layer laminated on the deposition layer have not been sufficiently examined.
The present inventors have discovered a new technical problem in that, when a barrier coat layer is formed on an inorganic oxide vapor deposition layer on a base film, the base film undergoes thermal shrinkage in the process of drying (heating) the barrier coat layer, causing fine cracks and the like in the inorganic oxide vapor deposition layer or the barrier coat layer, making it impossible to maintain the gas barrier properties (particularly the water vapor barrier properties) of the barrier film.

The present invention has been made in consideration of the above-mentioned background art and new technical problems, and its purpose is to provide a barrier film that has excellent gas barrier properties (particularly water vapor barrier properties) even after a drying (heating) process is performed by laminating a barrier coat layer on an inorganic oxide vapor deposition layer of a substrate film.

The inventors conducted extensive research to solve the above problems and discovered that the above problems can be solved by adjusting the thermal shrinkage rate of the barrier film in the MD direction, measured under specific conditions using a thermomechanical analyzer (TMA), to a certain range. The present invention was completed based on this discovery.

That is, according to the first aspect of the present invention,
A barrier film comprising an inorganic oxide vapor deposition layer and a substrate film,
The base film is a stretched polyester film,
The barrier film is subjected to a load of 2.92 x ¹⁰⁶ N/ ^m2 per unit cross-sectional area while being held at a temperature of 20°C for 5 minutes, then heated to 150°C at a heating rate of 10°C/min, held at 150°C for 10 minutes, and then cooled to 20°C at a heating rate of 10°C/min. The thermal shrinkage rate of the barrier film in the MD direction measured after this is between 0% and 0.75%.

In the first aspect of the present invention, the base film is preferably a biaxially oriented polyethylene terephthalate film.

In the first aspect of the present invention, the inorganic oxide vapor deposition layer is preferably an aluminum oxide vapor deposition film or a silicon oxide vapor deposition film.

In the first aspect of the present invention, it is preferable that a barrier coat layer is further laminated on the inorganic oxide vapor deposition layer.

In the first aspect of the present invention, the barrier coat layer is preferably a resin cured film of a metal alkoxide and a water-soluble polymer.

In the first aspect of the present invention, the barrier coat layer is preferably a cured resin film containing a reaction product formed by reacting a metal oxide with a phosphorus compound.

In the first aspect of the present invention, the barrier coat layer is preferably a resin cured film containing a carboxyl group-containing polymer crosslinked by a polyvalent metal compound.

According to a second aspect of the present invention,
A barrier film comprising an inorganic oxide vapor deposition layer having a barrier coat layer laminated thereon and a substrate film,
The base film is a stretched polyester film,
The barrier film is maintained at a temperature of 20°C for 5 minutes while applying a load of 2.92 x 106 N/ ^m2 per unit cross-sectional area to the barrier film, and then heated to 150°C at a heating rate of 10°C/min, maintained at the temperature of 150°C for 10 minutes, and then cooled to 20°C at a heating rate of 10°C/min. The thermal shrinkage rate of the barrier film substrate film in the MD direction measured after the heating is then measured is from 0% to 0.70%.

In the second aspect of the present invention, it is preferable that the base film is derived from biomass.

In the second aspect of the present invention, the barrier coat layer is preferably a resin cured film of a metal alkoxide and a water-soluble polymer.

In the second aspect of the present invention, the barrier coat layer is preferably a resin cured film containing a reaction product formed by reacting a metal oxide with a phosphorus compound.

In the second aspect of the present invention, the barrier coat layer is preferably a resin cured film containing a carboxyl group-containing polymer crosslinked by a polyvalent metal compound.

In a second aspect of the present invention, the inorganic oxide vapor deposition layer is an aluminum oxide vapor deposition film,
In the aluminum oxide vapor deposition film, an element bond structure represented by _Al3 is distributed,
When the barrier film is analyzed by time-of-flight secondary ion mass spectrometry (TOF-SIMS), the intensity ratio Al ₃ /Al ₂ O ₃ ×100 of the maximum Al ₃ concentration element bond structure portion in the aluminum oxide vapor deposition film is preferably 1 or more and 20 or less.

In a second aspect of the present invention, it is preferable that the maximum _Al3 concentration element bond structure portion is present at a depth position of 4% to 45% of the thickness of the aluminum oxide vapor-deposited film from the surface of the aluminum oxide vapor-deposited film on the opposite side to the substrate film.

In a second aspect of the present invention, the inorganic oxide vapor deposition layer is an aluminum oxide vapor deposition film,
a transition region is formed in the aluminum oxide vapor-deposited film, the transition region defining the peel strength between the surface of the base film and the aluminum oxide vapor-deposited film;
the transition region contains elementally bonded Al ₂ O ₄ H which transforms into aluminum hydroxide, as detected by etching using time-of-flight secondary ion mass spectrometry (TOF-SIMS);
It is preferable that the transformation rate of the transition region, which is defined by the ratio of the transformed transition region to the aluminum oxide vapor deposition film determined by etching the barrier coat layer and the aluminum oxide vapor deposition film using TOF-SIMS, is 5% or more and 60% or less.

In the first and second aspects of the present invention, the barrier film having a barrier coat layer preferably has an acid permeability of 1.0 ^cc /m2·atm·day or less, measured in accordance with JIS K7126 under an environment of a temperature of 23° C. and a humidity of 90% RH.

In the first and second aspects of the present invention, the barrier film having a barrier coat layer preferably has a water vapor permeability of 1.0 g/ ^m2 ·day or less, measured in accordance with JIS K7129 under an environment of a temperature of 40° C. and a humidity of 100% RH.

According to another aspect of the present invention, a packaging material is provided that includes a barrier film.

According to another aspect of the present invention, it is preferable that the heat seal layer, the adhesive layer, and the barrier layer made of the barrier film are provided in this order.

According to another aspect of the present invention, there is provided a packaging material comprising the above-mentioned barrier film,
After a moist heat sterilization treatment at 135° C. for 40 minutes, the normal peel strength between the base film and the aluminum oxide vapor-deposited film, measured in accordance with JIS K6854-2, is preferably 1.0 N or more.

According to another aspect of the present invention, it is preferable that the packaging material comprising the above-mentioned barrier film has a water-exfoliation peel strength of 1.0 N or more between the base film and the aluminum oxide vapor-deposited film measured in accordance with JIS K6854-2 after moist heat sterilization at 135°C for 40 minutes.

According to the present invention, a barrier film having excellent gas barrier properties (particularly water vapor barrier properties) can be provided by laminating a barrier coating layer on an inorganic oxide vapor deposition layer of a substrate film and then undergoing a drying (heating) process.

FIG. 1 is a schematic cross-sectional view showing one embodiment of a barrier film of the present invention. FIG. 2 is a graph analysis of the analysis results of a barrier film according to a preferred embodiment of the present invention by time-of-flight secondary ion mass spectrometry. FIG. 1 is a plan view showing an example of an apparatus for performing oxygen plasma pretreatment and forming an aluminum oxide vapor deposition film. FIG. 13 is a graph analysis of the results of time-of-flight secondary ion mass spectrometry analysis of a barrier film according to another preferred embodiment of the present invention. 1 is a schematic cross-sectional view showing one embodiment of a packaging material of the present invention. 1 is a schematic cross-sectional view showing one embodiment of a packaging material of the present invention. 1 is a schematic cross-sectional view showing one embodiment of a packaging material of the present invention. 1 is a schematic cross-sectional view showing one embodiment of a packaging material of the present invention. FIG. 2 is a diagram showing an example of a method for measuring peel strength. FIG. 2 is a diagram showing an example of a method for measuring peel strength. FIG. 1 is a graph showing the change in tensile stress with respect to the distance between a pair of grippers that pull two films to measure peel strength. FIG. 2 is a diagram showing an example of a method for measuring peel strength. FIG. 2 is a diagram showing an example of a method for measuring peel strength.

<Barrier film>
The barrier film according to the present invention comprises at least an inorganic oxide vapor deposition layer and a base film. It is preferable that the barrier film further comprises a barrier coat layer laminated on the inorganic oxide vapor deposition layer. A barrier film having such a layer structure has excellent gas barrier properties and can be suitably used as a barrier layer for retort packaging products that require gas barrier properties.

The barrier film having the following inorganic oxide vapor-deposited layer, which is the first aspect of the present invention, has a water vapor permeability measured in accordance with JIS K7129 under an environment of a temperature of 40°C and a humidity of 100% RH of preferably 5.0 g/ ^m2 ·day or less, more preferably 4.0 g/ ^m2 ·day or less, even more preferably 3.0 g/ ^m2 ·day or less, and even more preferably 2.0 g/ ^m2 ·day or less.
If the water vapor permeability falls within the above numerical range, the film has suitable water vapor barrier properties and can be used in various applications requiring water vapor barrier properties.

[0043] The barrier film comprising an inorganic oxide vapor-deposited layer having a barrier coat layer laminated thereon, which is the second aspect of the present invention, has a water vapor permeability measured in accordance with JIS K7129 under an environment of a temperature of 40°C and a humidity of 100% RH of preferably 1.0 g/ ^m2 ·day or less, more preferably 0.8 g/ ^m2 ·day or less, even more preferably 0.7 g/ ^m2 ·day or less, still more preferably 0.5 g/ ^m2 ·day or less, and particularly preferably 0.1 g/ ^m2 ·day or less.
If the water vapor permeability falls within the above numerical range, the film has suitable water vapor barrier properties and can be used in various applications requiring water vapor barrier properties.

The barrier film having the inorganic oxide vapor deposition layer described below, which is the first aspect of the present invention, has an acid permeability measured in accordance with JIS K7126 under an environment of a temperature of 23°C and a humidity of 90% RH of preferably 5.0 cc/ ^m2 atm day or less, more preferably 4.0 cc/ ^m2 atm day or less, even more preferably 3.0 cc/ ^m2 atm day, and even more preferably 2.0 cc/ ^m2 atm day.
If the oxygen permeability falls within the above range, the material has suitable oxygen barrier properties and can be used in a variety of applications requiring oxygen barrier properties.

[0043] The barrier film comprising an inorganic oxide vapor deposition layer having a barrier coat layer laminated thereon, which is the second aspect of the present invention, has an acid permeability measured in accordance with JIS K7126 under an environment of a temperature of 23°C and a humidity of 90% RH of preferably 1.0 cc/ ^m2 atm day or less, more preferably 0.8 cc/ ^m2 atm day or less, even more preferably 0.6 cc/ ^m2 atm day or less, still more preferably 0.5 cc/ ^m2 atm day or less, and particularly preferably 0.1 cc/ ^m2 atm day or less.
If the oxygen permeability falls within the above range, the material has suitable oxygen barrier properties and can be used in a variety of applications requiring oxygen barrier properties.

The barrier film having an inorganic oxide deposition layer laminated with the barrier coat layer described below, which is the second aspect of the present invention, preferably has a total light transmittance of 80% or more, more preferably 85% or more. The total light transmittance can be measured by a method conforming to JIS K7136 using an optical measuring device (a measuring device manufactured by Suga Test Instruments Co., Ltd. [model name: haze meter]). The total light transmittance is measured by setting the substrate film side of the barrier film so that it faces the light source side.

The barrier film having an inorganic oxide deposition layer laminated with the barrier coat layer described below, which is the second aspect of the present invention, preferably has a haze of less than 5%, and more preferably 2.5% or less. The haze can be measured using an optical measuring device (a measuring device manufactured by Suga Test Instruments Co., Ltd. [model name: haze meter]) according to a method conforming to JIS K7136. Note that the haze is measured by setting the substrate film side of the barrier film so that it faces the light source side.

The thermal shrinkage rate of the barrier film in the MD direction is adjusted to be within a certain range as measured using a thermomechanical analyzer (TMA) under the following conditions. The specific measurement conditions for the thermal shrinkage rate using a thermomechanical analyzer (TMA) are as follows:
While applying a load of 2.92 x ¹⁰⁶ N/ ^m2 per unit cross-sectional area to the barrier film, the film is held at 20°C for 5 minutes, then heated to 150°C at a heating rate of 10°C/min, held at 150°C for 10 minutes, and then cooled to 20°C at a heating rate of 10°C/min, after which the thermal shrinkage of the barrier film is measured.
As the thermomechanical analyzer (TMA), a commercially available product can be used, for example, a model named EXSTAR6000 manufactured by Seiko Instruments Inc. can be used.

The barrier film having the inorganic oxide vapor deposition layer described below, which is the first aspect of the present invention, has a thermal shrinkage rate in the MD direction measured under the above conditions of 0% or more and 0.75% or less, preferably 0.70% or less, and more preferably 0.65% or less.

The barrier film having an inorganic oxide deposition layer laminated with the barrier coat layer described below, which is the second aspect of the present invention, has a thermal shrinkage rate in the MD direction measured under the above conditions of 0% or more and 0.70% or less, preferably 0.65% or less, and more preferably 0.55% or less.

The thermal shrinkage of the barrier film can be adjusted by changing the stretching ratio of the polyester film, the heat setting temperature after stretching, the heat relaxation temperature, and the moisture content and degree of polymerization of the polyester film. If the thermal shrinkage of the barrier film is within the above range, even if the barrier film shrinks due to heating in the drying process during the formation of the barrier coat layer, fine cracks are unlikely to occur in the inorganic oxide deposition layer or barrier coat layer formed on the base film, and the gas barrier properties obtained by the inorganic oxide deposition layer or barrier coat layer can be maintained. Therefore, the barrier film of the present invention can be used in various applications requiring gas barrier properties (particularly water vapor barrier properties).

The layer structure of a barrier film according to one embodiment of the present invention will be described with reference to the drawings. The barrier film 11 shown in FIG. 1 comprises an inorganic oxide deposition layer 13 on one side of a substrate film 12. The barrier film 11 may further comprise a barrier coat layer 14 on the inorganic oxide deposition layer 13. Each layer constituting the barrier film of the present invention will be described below.

(Base film)
The substrate film used in the barrier film may be a uniaxially or biaxially stretched polyester film. The substrate film is preferably one whose MD heat shrinkage is adjusted to a certain range as measured under the following conditions using a thermomechanical analyzer (TMA).

Specific conditions for measuring the thermal shrinkage rate using a thermomechanical analyzer (TMA) are as follows.
While applying a load of 2.92 x ¹⁰⁶ N/ ^m2 per unit cross-sectional area to the base film, the film is held at 20°C for 5 minutes, then the temperature is increased to 150°C at a rate of 10°C/min, held at 150°C for 10 minutes, and then cooled to 20°C at a rate of 10°C/min, after which the thermal shrinkage of the base film is measured.
As the thermomechanical analyzer (TMA), a commercially available product can be used, for example, a model named EXSTAR6000 manufactured by Seiko Instruments Inc. can be used.

The base film has a thermal shrinkage rate in the MD direction measured under the above conditions of 0% or more and 1.00% or less, preferably 0.95% or less, and more preferably 0.90% or less.

The heat shrinkage rate of the base film can be adjusted by changing the stretching ratio of the polyester film, the heat setting temperature after stretching, the heat relaxation temperature, and the moisture content and degree of polymerization of the polyester film. If the heat shrinkage rate of the base film is within the above range, even if the base film shrinks due to heating in the drying process during the formation of the barrier coat layer, fine cracks are unlikely to occur in the inorganic oxide deposition layer or barrier coat layer formed on the base film, and the gas barrier properties obtained by the inorganic oxide deposition layer or barrier coat layer can be maintained. Therefore, the barrier film of the present invention can be used in various applications requiring gas barrier properties (particularly water vapor barrier properties).

(Polyethylene terephthalate film)
The type of polyester film is not particularly limited, but examples thereof include polyethylene terephthalate films, and specifically, polyethylene terephthalate films derived from general petroleum fuels can be used.
In addition to the polyethylene terephthalate film that is generally derived from petroleum fuel, the following polyester films can also be used.

(Polybutylene terephthalate film (PBT))
Since polybutylene terephthalate films have a high heat distortion temperature, excellent mechanical strength and electrical properties, and good moldability, when used in packaging bags for containing food and other contents, they can prevent the packaging bag from being deformed or its strength from being reduced during retort treatment. The polybutylene terephthalate film is a film containing polybutylene terephthalate (hereinafter also referred to as PBT) as a main component, and is preferably a resin film containing 60% by mass or more of PBT.

(Biomass-derived polyester film)
The biomass-derived polyester film is made of a resin composition containing a polyester composed of diol units and dicarboxylic acid units as a main component, and the diol units of the resin composition are ethylene glycol derived from biomass. The biomass-derived polyester film may contain, based on the entire resin composition, preferably 50 to 95 mass %, more preferably 50 to 90 mass %, of a polyester whose dicarboxylic acid units are dicarboxylic acids derived from fossil fuels.

Biomass-derived ethylene glycol is made from ethanol (biomass ethanol) produced from biomass such as sugar cane and corn. For example, biomass-derived ethylene glycol can be obtained by converting biomass ethanol into ethylene oxide using a conventional method. Commercially available biomass ethylene glycol may also be used; for example, biomass ethylene glycol available from India Glycoal Limited can be suitably used.

The dicarboxylic acid units of the polyester use dicarboxylic acids derived from fossil fuels. As the dicarboxylic acid, aromatic dicarboxylic acids, aliphatic dicarboxylic acids, and derivatives thereof can be used. As the aromatic dicarboxylic acid, terephthalic acid and isophthalic acid can be mentioned, and as the derivatives of aromatic dicarboxylic acids, lower alkyl esters of aromatic dicarboxylic acids, specifically, methyl esters, ethyl esters, propyl esters, butyl esters, and the like can be mentioned. Among these, terephthalic acid is preferred, and as the derivatives of aromatic dicarboxylic acids, dimethyl terephthalate is preferred.

The resin composition forming the biomass-derived polyester film may contain one or more of the following: polyester derived from fossil fuels, recycled polyester from polyester products derived from fossil fuels, and recycled polyester from polyester products derived from biomass. The resin composition forming the biomass-derived polyester film may contain one or more of the following: polyester derived from fossil fuels, recycled polyester from polyester products derived from fossil fuels, and recycled polyester from polyester products derived from biomass, at a ratio of 5 to 45% by mass.

Carbon dioxide in the atmosphere contains a certain proportion of ¹⁴ C (105.5 pMC), and it is known that ^{the 14} C content in plants that grow by absorbing carbon dioxide from the atmosphere, such as corn, is also about 105.5 pMC. It is also known that fossil fuels contain almost no ¹⁴ C. Therefore, by measuring the proportion of ¹⁴ C in the total carbon atoms in polyester, the proportion of carbon derived from biomass can be calculated.
In the present invention, the "biomass degree" refers to the weight ratio of biomass-derived components. Taking PET as an example, since PET is a polymer of ethylene glycol containing 2 carbon atoms and terephthalic acid containing 8 carbon atoms in a molar ratio of 1:1, when only biomass-derived ethylene glycol is used, the weight ratio of biomass-derived components in PET is 31.25%, and the biomass degree is 31.25% (molecular weight derived from biomass-derived ethylene glycol/molecular weight of one polymerization unit of polyester=60÷192).
The weight ratio of the biomass-derived component in the fossil fuel-derived polyester is 0%, and the biomass degree of the fossil fuel-derived polyester is 0%. In the present invention, the biomass degree in the base film is preferably 5.0% or more, and more preferably 10.0% or more. The biomass degree in the base film is preferably 30.0% or less.

(recycled polyethylene terephthalate)
A polyethylene terephthalate film containing polyethylene terephthalate recycled by mechanical recycling, specifically, PET obtained by mechanically recycling PET bottles, the diol component of which is ethylene glycol, and the dicarboxylic acid components of which are terephthalic acid and isophthalic acid. The content of the isophthalic acid component in the total dicarboxylic acid components constituting the PET is preferably 0.5 mol % or more and 5 mol % or less, more preferably 1.0 mol % or more and 2.5 mol % or less.

Mechanical recycling is a method in which collected polyethylene terephthalate resin products such as PET bottles are generally crushed and washed with an alkali to remove dirt and foreign matter from the surface of the PET resin products, and then the products are dried at high temperature and reduced pressure for a certain period of time to diffuse and decontaminate the contaminants remaining inside the PET resin, removing dirt from the resin products made of PET resin and returning them to PET resin.

Recycled polyethylene terephthalate preferably contains recycled PET at a ratio of 50% by weight to 95% by weight, and may also contain virgin PET. Virgin PET may contain ethylene glycol as a typical diol component and terephthalic acid as a dicarboxylic acid component, or may further contain isophthalic acid.

The thickness of the polyester film is not particularly limited, but is preferably 5 μm or more and 2000 μm or less, more preferably 7 μm or more and 1000 μm or less, and even more preferably 8 μm or more and 100 μm or less.

(surface treatment)
In the present invention, before forming an inorganic oxide vapor deposition film on the above-mentioned substrate film, a surface treatment may be performed in advance. This can improve adhesion to the inorganic oxide vapor deposition film. Similarly, a surface treatment can be performed on the vapor deposition layer to improve adhesion to the gas barrier coating film. Such surface treatments include pretreatments such as corona discharge treatment, ozone treatment, low-temperature plasma treatment using oxygen gas or nitrogen gas, glow discharge treatment, and oxidation treatment using chemicals.

Surface treatment can also be performed by applying a primer coating agent, an undercoat agent, or a vapor deposition anchor coating agent, as desired. Examples of the coating agent include polyester resins, polyamide resins, polyurethane resins, epoxy resins, phenol resins, (meth)acrylic resins, polyvinyl acetate resins, polyolefin resins such as polyethylene or polypropylene, or copolymers or modified resins thereof, and resin compositions containing cellulose resins as the main component of the vehicle.

Among these surface treatments, corona treatment and plasma treatment are particularly suitable. For example, plasma treatment is a method of surface modification using plasma gas generated by ionizing gas by arc discharge. Inorganic gases such as oxygen gas, nitrogen gas, argon gas, and helium gas can be used as plasma gas. For example, in-line plasma treatment can remove moisture, dust, etc. from the surface of the substrate film, and can also perform surface treatment such as smoothing and activation of the surface. Plasma treatment can also be performed after deposition to improve adhesion. In the present invention, plasma discharge treatment is preferably performed as the plasma treatment, taking into consideration the plasma output, type of plasma gas, supply amount of plasma gas, treatment time, and other conditions. In addition, devices such as direct current glow discharge, high frequency discharge, and microwave discharge can be used as a method of generating plasma. Plasma treatment can also be performed by atmospheric pressure plasma treatment.

(Inorganic oxide vapor deposition layer)
The deposition layer formed on the substrate film is a deposition film of an inorganic oxide formed by chemical vapor deposition (CVD) or physical vapor deposition (PVD).

The inorganic oxide is not particularly limited, but a vapor deposition film of an oxide of silicon, aluminum, magnesium, calcium, potassium, tin, sodium, boron, titanium, lead, zirconium, yttrium, or the like can be used. In particular, the inorganic oxide vapor deposition layer is preferably a vapor deposition film of aluminum oxide or silicon oxide, and more preferably a vapor deposition film of aluminum oxide. The inorganic oxide is expressed, for example, as MO _{x (} wherein M represents an inorganic element, and the value of X varies depending on the inorganic element), such as _AlO x or SiO x. In the present invention, from the viewpoint of transparency and gas barrier property, when M is aluminum (Al), the value of X is preferably 0.5 to 2.0, and when M is silicon (Si), the value of X is preferably 1 to 2.

As the inorganic oxide deposition layer, it is preferable to provide an aluminum oxide deposition film by physical vapor deposition, because it is easy to handle as a deposition material. The aluminum oxide deposition film formed by physical vapor deposition has excellent adhesion to the surface of the gas barrier coating film. Examples of physical vapor deposition methods include physical vapor deposition methods (Physical Vapor Deposition method, PVD method) such as vacuum deposition method, sputtering method, ion plating method, and ion cluster beam method.

Specifically, the deposition film can be formed using a vacuum deposition method in which aluminum or its oxide is used as a raw material, which is heated to vaporize and then deposited on one side of a substrate film; an oxidation reaction deposition method in which aluminum or its oxide is used as a raw material, which is oxidized by introducing oxygen and then deposited on one side of a substrate film; or a plasma-assisted oxidation reaction deposition method in which the oxidation reaction is assisted by plasma. The deposition material can be heated, for example, by resistance heating, high-frequency induction heating, electron beam heating (EB), etc.

In addition, when the inorganic oxide deposition layer is a silicon oxide deposition film, it is preferable to provide the silicon oxide deposition film by chemical vapor deposition from the viewpoint of bending resistance and gas barrier properties. Examples of chemical vapor deposition methods include chemical vapor deposition methods (chemical vapor deposition methods, CVD methods) such as plasma chemical vapor deposition, low-temperature plasma chemical vapor deposition, thermal chemical vapor deposition, and photochemical vapor deposition. Specifically, a silicon oxide deposition film can be formed on one side of the substrate film by using a low-temperature plasma chemical vapor deposition method that uses a deposition monomer gas such as an organic silicon compound as a raw material, an inert gas such as argon gas or helium gas as a carrier gas, and oxygen gas as an oxygen supply gas, and uses a low-temperature plasma generator or the like. As the low-temperature plasma generator, for example, a generator such as a high-frequency plasma, a pulse wave plasma, or a microwave plasma can be used. It is preferable to use a generator using a high-frequency plasma method, since it is possible to obtain a highly active and stable plasma.

As the vapor deposition monomer gas of the organosilicon compound that forms the silicon oxide vapor deposition film, for example, 1,1,3,3-tetramethyldisiloxane, hexamethyldisiloxane, vinyltrimethylsilane, methyltrimethylsilane, hexamethyldisilane, methylsilane, dimethylsilane, trimethylsilane, diethylsilane, propylsilane, phenylsilane, vinyltriethoxysilane, vinyltrimethoxysilane, tetramethoxysilane, tetraethoxysilane, phenyltrimethoxysilane, methyltriethoxysilane, octamethylcyclotetrasiloxane, etc. can be used. Among these, it is particularly preferable to use 1,1,3,3-tetramethyldisiloxane or hexamethyldisiloxane as a raw material in terms of its ease of handling and the properties of the continuous film formed. In addition, in the above, for example, argon gas, helium gas, etc. can be used as the inert gas.

The silicon oxide vapor deposition film is mainly composed of silicon oxide, but may further contain at least one compound consisting of one or more elements of carbon, hydrogen, nitrogen, silicon, or oxygen by chemical bonds. For example, when a compound having a C-H bond, a compound having a Si-H bond, or a carbon unit is graphite-like, diamond-like, fullerene-like, etc., it may further contain a raw material organic silicon compound or a derivative thereof by chemical bonds. For example, a hydrocarbon having a _CH3 site, hydrosilica such as _SiH3 silyl, _SiH2 silylene, and a hydroxyl group derivative such as _SiH2OH silanol can be mentioned. In addition to the above, the type and amount of the compound contained in the silicon oxide vapor deposition film can be changed by changing the conditions of the vapor deposition process.

The thickness of the inorganic oxide deposition layer is preferably 3 nm or more and 100 nm or less, more preferably 4 nm or more and 50 nm or less, even more preferably 5 nm or more and 30 nm or less, and even more preferably 9 nm or more and 14 nm or less. If the thickness of the inorganic oxide deposition layer is within the above range, sufficient gas barrier properties can be exhibited.

In a preferred embodiment of the present invention, the inorganic oxide vapor-deposited layer is an aluminum oxide vapor-deposited film, and a transition region that determines the peel strength between the surface of the base film and the aluminum oxide vapor-deposited film is formed in the aluminum oxide vapor-deposited film, and the transition region contains elementally bonded Al ₂ O ₄ H that is transformed into aluminum hydroxide as detected by etching using time-of-flight secondary ion mass spectrometry (TOF-SIMS), and a transformation rate of the transition region, defined as a ratio of the transformed transition region to the aluminum oxide vapor-deposited film determined by etching the barrier coat layer and the aluminum oxide vapor-deposited film using TOF-SIMS, is 5% or more and 60% or less. This makes it possible to improve the normal state adhesion and water-resistant adhesion of the interface between the base film and the aluminum oxide vapor-deposited film of the barrier film after moist heat sterilization treatment at 135° C. for 40 minutes (high retort treatment) or moist heat sterilization treatment at 121° C. for 40 minutes (semi-retort treatment), and to make the gas barrier property less likely to deteriorate. The transformation rate of the transition region is preferably 5% or more and 45% or less, and more preferably 5% or more and 30% or less.

The transition region is defined using time-of-flight secondary ion mass spectrometry (TOF-SIMS) for an aluminum oxide deposition film defined by etching using TOF-SIMS, including elementally bonded Al ₂ O ₄ H that transforms into aluminum hydroxide detected by etching using TOF-SIMS.

Secondary ion mass spectrometry (SIMS) is a method for analyzing elemental concentration distribution by irradiating the surface of a sample to be analyzed with a primary ion beam and performing mass analysis on the secondary ions that are sputtered and released from the sample surface. In this secondary ion mass spectrometry method, the secondary ion intensity is detected while sputtering is progressing. Therefore, by converting the transition time into depth for data on the time transition of the ion intensity of the secondary ions, i.e., the ions of the element to be detected or molecular ions bonded to the element to be detected, the concentration distribution of the element to be detected in the depth direction of the sample surface can be known.

The conversion of transition time to depth is done by using a surface roughness meter to measure the depth of the depression formed on the sample surface by the irradiation of primary ions, calculating the average sputtering rate from this depression depth and transition time, and converting the irradiation time (i.e., transition time) to depth (amount of sputtering) under the assumption that the sputtering rate is constant.

By repeatedly soft-etching the aluminum oxide vapor-deposited film of the barrier film at the above-mentioned constant speed with a Cs (cesium) ion gun and measuring ions derived from the aluminum oxide vapor-deposited film and ions derived from the base film using time-of-flight secondary ion mass spectrometry (TOF-SIMS), a transition region that determines the peel strength is formed between the surface of the base film and the vapor-deposited film mainly composed of the aluminum oxide vapor-deposited film. The transition region contains elemental bond Al ₂ O ₄ H that is transformed into aluminum hydroxide detected by etching using time-of-flight secondary ion mass spectrometry (TOF-SIMS), and a barrier film having barrier properties with improved normal adhesion and water-resistant adhesion can be specified by specifying the transformation ratio of the transition region transformed into aluminum hydroxide, which is defined by the ratio of the transformed transition region defined by time-of-flight secondary ion mass spectrometry to the aluminum oxide vapor-deposited film defined by etching using time-of-flight secondary ion mass spectrometry (TOF-SIMS).

Specifically, a time-of-flight secondary ion mass spectrometer is used to etch the outermost surface of the aluminum oxide vapor-deposited film with Cs, and the elemental bonds at the interface between the aluminum oxide vapor-deposited film and the base film and the elemental bonds in the vapor-deposited film are measured. Actual measurement graphs are obtained for the measured elements and elemental bonds (Figure 2: graph analysis diagram). In order to narrow as much as possible the transition region at the interface between the base film and the vapor-deposited film formed by aluminum hydroxide in the aluminum oxide vapor-deposited film, attention is focused on the elemental _{bond Al2O4H} , and 1) the position where the intensity of the graph of element _C6 is half is determined as the interface between the base film and aluminum oxide, and the region from the surface to the interface is determined as the aluminum _{oxide vapor-deposited film, 2) the peak in the graph representing the elemental bond Al2O4H is} determined, and the region from the peak to the interface is determined as the transition region, and 3) the conversion rate to aluminum _{hydroxide in the transition region is determined as (transition region from the peak of the elemental bond Al2O4H to} the interface/aluminum oxide vapor-deposited film) x 100 (%).

In one embodiment, the aluminum oxide vapor deposition film is preferably formed by performing oxygen plasma pretreatment on the surface of the base film using a plasma pretreatment device described below. This allows the formation of an aluminum oxide vapor deposition film having a conversion rate in the above-mentioned transition region, and improves the normal state adhesion and water-resistant adhesion between the base film and the aluminum oxide vapor deposition film. The oxygen plasma treatment is performed with a bias voltage perpendicular to the base film. The oxygen plasma pretreatment is a pretreatment for further strengthening and improving the normal state adhesion and water-resistant adhesion between various resin films or sheets and the aluminum oxide vapor deposition film, and can be performed in the following device.

As shown in FIG. 3, the roller-type continuous vapor deposition film forming apparatus 20, which is suitable for use in the manufacture of barrier films having aluminum oxide vapor deposition films, has partitions 45a to 45c formed in the decompression chamber 22. The partitions 45a to 45c form the substrate transport chamber 22A, the plasma pretreatment chamber 22B, and the film formation chamber 22C. In particular, the plasma pretreatment chamber 22B and the film formation chamber 22C are formed as spaces surrounded by the partitions and the partitions 45a to 45c, and each chamber further has an exhaust chamber formed inside as necessary.

In the plasma pretreatment chamber 22B, a plasma pretreatment roller 30 that transports the substrate film S to be pretreated and enables plasma treatment is provided so that a portion of the roller 30 is exposed to the substrate transport chamber 22A, and the substrate film S is moved to the plasma pretreatment chamber 22B while being wound up.

The plasma pretreatment chamber 22B and the deposition chamber 22C are provided adjacent to the substrate transport chamber 22A, and the substrate film S can be moved without being exposed to the atmosphere. The pretreatment chamber 22B and the substrate transport chamber 22A are connected by a rectangular hole, through which a part of the plasma pretreatment roller 30 protrudes toward the substrate transport chamber 22A, and a gap is opened between the wall of the transport chamber and the pretreatment roller 30, and the substrate film S can be moved from the substrate transport chamber 22A to the deposition chamber 22C through the gap. The same structure is also formed between the substrate transport chamber 22A and the deposition chamber 22C, and the substrate film S can be moved without being exposed to the atmosphere.

The substrate transport chamber 22A is provided with a winding roller as a winding means for winding up the substrate film S, which has a vapor deposition film formed on one side and has been moved back into the substrate transport chamber 22A by the deposition roller 33, into a roll, so that the substrate film S, which has a vapor deposition film formed on it, can be wound up.

When manufacturing a barrier film having an aluminum oxide vapor deposition film, the plasma pretreatment chamber 22B is configured to separate the space where the plasma is generated from other areas and to efficiently evacuate the opposing space, making it easier to control the plasma gas concentration and improving productivity. The pretreatment pressure formed by reducing the pressure can be set and maintained at approximately 0.1 Pa to 100 Pa, and in particular, the treatment pressure for oxygen plasma pretreatment is preferably 1 to 20 Pa to achieve a preferred transformation rate in the transition region of the aluminum oxide vapor deposition film.

The transport speed of the base film S is not particularly limited, but from the viewpoint of production efficiency, it can be at least 200 to 1000 m/min. In particular, the transport speed for oxygen plasma pretreatment is preferably 300 to 800 m/min in order to obtain the transformation rate in the transition region of the aluminum oxide vapor deposition film.

The plasma pretreatment roller 30 that constitutes the plasma pretreatment device is intended to prevent the substrate film S from shrinking or being damaged by heat during plasma treatment by the plasma pretreatment means, and to apply oxygen plasma P to the substrate film S uniformly and over a wide area.
It is preferable that the pretreatment roller 30 can be adjusted to a constant temperature between −20° C. and 100° C. by adjusting the temperature of a temperature adjustment medium circulating within the pretreatment roller.

The plasma pretreatment means includes a plasma supply means and a magnetic forming means. The plasma pretreatment means cooperates with the plasma pretreatment roller 30 to confine oxygen plasma P near the surface of the substrate film S.

The plasma pretreatment means is provided so as to cover a portion of the pretreatment roller 30. Specifically, the plasma supply means and magnetic field forming means constituting the plasma pretreatment means are disposed along the surface near the outer periphery of the pretreatment roller 30, and are installed so as to form a gap sandwiched between the pretreatment roller 30, plasma supply nozzles 32a to 32c which supply plasma raw material gas and also serve as electrodes for generating plasma P, and magnetic field forming means having magnets 31 or the like for promoting the generation of plasma P.
As a result, plasma supply nozzles 32a to 32c are opened in the space of the gap to spray plasma toward the substrate surface, making the gap a plasma formation region, and further forming a region of high plasma density in the vicinity of the pretreatment roller 30 and the surface of the substrate film S, thereby enabling oxygen plasma pretreatment to be performed to form a plasma-treated surface on one side of the substrate film S.

The plasma supply means of the plasma pretreatment means includes a raw material volatilization supply device 28 connected to a plasma supply nozzle provided outside the decompression chamber 22, and a raw material gas supply line that supplies raw material gas from the device. The plasma raw material gas to be supplied is oxygen alone or a mixed gas of oxygen gas and an inert gas, which is supplied from a gas storage section through a flow controller while the gas flow rate is measured. The inert gas may be one or more mixed gases selected from the group consisting of argon, helium, and nitrogen. When a mixed gas of oxygen gas and an inert gas is used as the plasma raw material gas, it is preferable to use a mixed gas in which the oxygen partial pressure is higher than the inert gas partial pressure, from the viewpoint of normal adhesion and water-resistant adhesion between the substrate film and the aluminum oxide vapor deposition film.

These gases are mixed at a predetermined ratio as necessary to form a plasma raw material gas alone or a mixed gas for plasma formation, which is then supplied to the plasma supply means. The single gas or mixed gas is supplied to the plasma supply nozzles 32a to 32c of the plasma supply means, and is supplied to the vicinity of the outer periphery of the pretreatment roller 30 where the supply ports of the plasma supply nozzles 32a to 32c open.
The nozzle opening is directed toward the substrate film S on the pretreatment roller 30, and is arranged and configured to enable the oxygen plasma P to be uniformly diffused and supplied to the entire surface of the substrate film S, thereby enabling uniform plasma pretreatment of a large area of the substrate film S.

In the oxygen plasma pretreatment to obtain a conversion rate in the transition region of the aluminum oxide vapor deposition film, the mixture ratio of oxygen gas to the inert gas, that is, oxygen gas/inert gas, is preferably 1/1 to 6/1, and more preferably 3/2.5 to 3/1.
By setting the mixing ratio to 1/1 to 6/1, the film formation energy of the evaporated aluminum on the substrate film increases, and by setting the mixing ratio to 3/2.5 to 3/1, aluminum hydroxide is formed near the interface of the substrate, i.e., the conversion rate of the transition region decreases. Furthermore, by setting the mixing ratio to 3/2.5 to 3/1, the plasma discharge can be stabilized.

The plasma supply nozzles 32a to 32c function as opposing electrodes for the pretreatment roller 30 and are designed to have an electrode function. The plasma raw material gas supplied is excited by the potential difference caused by the high-frequency voltage, low-frequency voltage, etc. supplied between the nozzles and the pretreatment roller 30, generating and supplying plasma P.

Specifically, the plasma supply means of the plasma pretreatment means has a plasma pretreatment roller as a plasma power source, applies an AC voltage with a frequency of 10 Hz to 2.5 GHz between the opposing electrode, and performs input power control or impedance control, etc., to enable any voltage to be applied between the plasma pretreatment roller 30. The plasma supply means is provided with a power source 42 that can apply a bias voltage to make the oxygen plasma P, which can be used to physically or chemically modify the surface properties of the substrate, a positive potential.
The plasma intensity per unit area employed in the present invention is 50 to 8000 W·sec/m2; if it is less than ⁵⁰ W·sec/m2, the effect of the plasma pretreatment is not observed, and if it exceeds 8000 W·sec/ ^m2 , the substrate tends to be deteriorated by the plasma, such as wear, damage, coloring, and baking. In particular, the plasma intensity of the oxygen plasma pretreatment is preferably 100 to 500 W·sec/ ^m2 in order to achieve a transformation rate in the transition region of the aluminum oxide vapor deposition film. By applying the above plasma intensity with a bias voltage perpendicular to the substrate film, the normal adhesion and water-resistant adhesion to the aluminum oxide vapor deposition film are stably strengthened compared to conventional methods.

The plasma pretreatment means has a magnetic field forming means, which is provided with an insulating spacer and a base plate in a magnet case, and a magnet 31 is provided on the base plate. An insulating shield plate is provided on the magnet case, and an electrode is attached to the insulating shield plate.
Therefore, the magnet case and the electrodes are electrically insulated, and even if the magnet case is installed and fixed in the decompression chamber 22, the electrodes can be kept at an electrically floating level.

A power supply wiring 41 is connected to the electrodes, and the power supply wiring 41 is connected to a power source 42. Furthermore, a temperature adjustment medium pipe for cooling the electrodes and the magnet 31 is provided inside the electrodes.
The magnet 31 is provided so that oxygen plasma P from plasma supply nozzles 32a to 32c, which serve as electrodes and plasma supply means, can be concentrated and applied to the substrate film S. By providing the magnet 31, reactivity in the vicinity of the substrate surface is increased, making it possible to form a good plasma pre-treated surface at high speed.

The magnet 31 has a magnetic flux density of 10 to 10,000 gauss at the surface of the base film S. If the magnetic flux density at the surface of the base film S is 10 gauss or more, it is possible to sufficiently increase the reactivity near the base surface, and a good pre-treated surface can be formed at high speed.

The arrangement of the magnets 31 of the electrode causes the ions and electrons formed during plasma pretreatment to move in accordance with this arrangement. Therefore, even when plasma pretreatment is performed on a substrate film S having a large area of, for example, 1 ^m2 or more, the electrons, ions, and substrate decomposition products are uniformly diffused over the entire electrode surface, making it possible to perform the desired uniform and stable pretreatment with the desired plasma intensity, even when the substrate film S has a large area.

Next, the substrate film S that has been treated with the special oxidation plasma is moved from the substrate transport chamber 22A to the deposition chamber 22C by guide rolls 24a to 24d to guide it to the next deposition chamber 22C, where an aluminum oxide deposition film is formed in the deposition section. The deposition of the aluminum oxide deposition film is described below.

The film forming chamber 22C is placed under reduced pressure, and the substrate film S, which has been pretreated in the plasma pretreatment device, is wound around and transported with the treated surface of the substrate film S facing outward, and a film forming roller 33 for film forming processing and a target of a film forming source 34 arranged opposite the film forming roller are evaporated to form a vapor deposition film on the surface of the substrate film.
The vapor deposition film forming means 34 is of a resistance heating type, and uses an aluminum metal wire as an aluminum evaporation source. While supplying oxygen to oxidize the aluminum vapor, an aluminum oxide vapor deposition film is formed on the surface of the substrate film S.

In one embodiment, multiple aluminum metal wires are placed in a boat-shaped (referred to as a "boat type") deposition vessel in the axial direction of the roller 33 and heated by resistance heating. In this way, the aluminum metal material can be evaporated while reducing the amount of heat supplied, and an aluminum oxide deposition film can be formed while minimizing the thermal deformation of the substrate film S.

In one embodiment, in applications for packaging materials in which high-speed retort treatment of contents is performed, it is particularly preferred to perform oxygen plasma pretreatment with a mixture ratio of oxygen gas and inert gas of 3/2.5 to 3/1, a pretreatment pressure of 1 to 20 Pa, and a plasma intensity of 100 to 500 W·sec/ ^m2 , and further to set the thickness of the inorganic oxide vapor deposition layer to 9 to 14 nm. This can further improve the normal state adhesion and water-resistant adhesion at the interface between the substrate film and aluminum oxide vapor deposition film of the barrier film, and make the gas barrier property less susceptible to deterioration.

In another preferred embodiment of the present invention, the inorganic oxide vapor deposition layer is an aluminum oxide vapor deposition film, in which an elemental bond structure represented by _Al3 is distributed, and when the barrier film is analyzed by time-of-flight secondary ion mass spectrometry (TOF-SIMS), the intensity ratio _Al3 / _Al2O3 x 100 of the elemental bond structure portion with the maximum _Al3 concentration in the aluminum oxide vapor deposition film is 1 or more and ₂₀ or less. By making the intensity ratio 1 or more, the denseness of the vapor deposition film can be improved, and the gas barrier property can be further improved. Furthermore, by making the intensity ratio 20 or less, coloring due to aluminum can be suppressed, and a barrier film with excellent transparency can be obtained. The intensity ratio is preferably 1 or more and 10 or less.

In the aluminum oxide vapor-deposited film, elemental bonding structures represented by _Al3 are distributed, and the abundance ratio of the elemental bonding structures represented by _Al3 varies depending on the depth position in the aluminum oxide vapor-deposited film.
The abundance ratio of the element bonding structure represented by _Al3 can be expressed by the abundance ratio with respect to _Al2O3 (aluminum oxide), _{and specifically, it can be expressed by the intensity ratio Al3/Al2O3, which is the ratio between the intensity of Al3 and the intensity of Al2O3 detected by time -} of-flight secondary _ion mass spectrometry (TOF _- SIMS).

It is preferable that the maximum Al ₃ concentration element bond structure portion is present at a depth position of 4% to 45% of the thickness of the aluminum oxide vapor deposition film from the surface of the aluminum oxide vapor deposition film opposite to the substrate film. As a result, the outermost surface of the aluminum oxide vapor deposition film becomes an aluminum oxide film having a degree of oxidation and hydroxide, and adhesion with the barrier coat layer is improved, thereby improving the gas barrier property. In addition, by providing the maximum Al ₃ concentration element bond structure portion at a depth position of 4% to 45% of the thickness of the aluminum oxide vapor deposition film, the denseness of the vapor deposition film is improved, and the reactivity between the barrier coat composition that has soaked in and aluminum when the barrier coat layer is laminated is easily caused, and adhesion with the barrier coat layer is further improved.

The _Al3 concentration and _Al2O3 concentration in the aluminum oxide vapor deposition film, as well as the depth position of the maximum _Al3 concentration element bond structure portion, are measured using time-of-flight secondary ion mass spectrometry (TOF-SIMS), _the depth position of the maximum _Al3 concentration element bond structure portion is identified, and the _intensity ratio _Al3 / _Al2O3 is calculated.

Here, by detecting the secondary ion intensity while the sputtering is proceeding, the concentration distribution of the detectable element in the depth direction of the sample surface can be obtained by converting the transition time into depth data for the ion intensity of the secondary ions, i.e., the ions of the detectable element or molecular ions bonded to the detectable element.
Then, the depth of the depression formed on the sample surface by the irradiation of the primary ions is measured in advance using a surface roughness meter, and the average sputtering rate is calculated from the depression depth and transition time. Under the assumption that the sputtering rate is constant, the depth (sputtering amount) can be calculated from the irradiation time (i.e., transition time) or the number of irradiation cycles.

For the aluminum oxide vapor deposition film of the barrier film, preferably a Cs (cesium) ion gun is used to measure deep regions, and soft etching is repeated at a constant speed as described above while measuring _Al3 and _Al2O3 ions derived from the aluminum _oxide vapor deposition film layer and _C6 ions derived from the base film, thereby allowing the intensity ratio of each ion to be calculated.

In addition, by identifying the interface between the aluminum oxide vapor deposition layer and the base film, it is possible to know at what depth from the interface the maximum value of the detected ions exists. In other words, by defining the position where the intensity of the _C6 ions is half of its maximum value as the interface between the base film and the aluminum oxide film, it is possible to know at what depth in the aluminum oxide film the maximum value of the intensity of the detected ions exists.

The measurement results can be obtained, for example, as a graph as shown in Fig. 4. In the graph of Fig. 4, the unit of the vertical axis (intensity) is the intensity of the measured ions, and the unit of the horizontal axis (cycle) is the number of etching cycles.
Then, the depth within the aluminum oxide vapor-deposited film, the _Al3 intensity, and _{the Al2O3 intensity} in each cycle are obtained, and the intensity ratio _Al3 / _Al2O3 is calculated.The intensity ratio _Al3 / _Al2O3 at the time when the _{maximum Al3} intensity is shown and the ratio of said depth to the thickness of the aluminum _oxide vapor-deposited film can be calculated.

In one embodiment, the aluminum oxide vapor deposition film is preferably formed using the apparatus described below. This allows the aluminum oxide vapor deposition film to have a high strength ratio, and improves the barrier properties of the barrier film. The aluminum oxide vapor deposition film may be formed using a roller-type continuous vapor deposition film forming apparatus 20 as shown in FIG. 3.
In a further preferred embodiment, the aluminum oxide vapor-deposited film is formed by subjecting the surface of the substrate film to the oxygen plasma pretreatment described above, which can improve the barrier properties and can also improve the normal adhesion and water-resistant adhesion at the interface between the substrate film and the aluminum oxide vapor-deposited film.
Hereinafter, a method for forming an aluminum oxide vapor deposition film will be described with reference to FIG.

As shown in FIG. 3, the roller-type continuous vapor deposition film forming apparatus 20, which is suitable for use in the manufacture of barrier films having aluminum oxide vapor deposition films, has partitions 45a to 45c formed in the decompression chamber 22. The partitions 45a to 45c form the substrate transport chamber 22A, the plasma pretreatment chamber 22B, and the film formation chamber 22C. In particular, the plasma pretreatment chamber 22B and the film formation chamber 22C are formed as spaces surrounded by the partitions and the partitions 45a to 45c, and each chamber further has an exhaust chamber formed inside as necessary.

The oxygen plasma pretreatment process has been described above, so a detailed explanation will be omitted here.

The plasma-oxidized substrate film S is moved from the substrate transport chamber 22A to the deposition chamber 22C by guide rolls 24a-24d to guide it to the deposition chamber 22C, where an aluminum oxide vapor deposition film is formed.

The film forming chamber 22C is placed under reduced pressure, and the substrate film S is wrapped around and transported with the treated surface of the substrate film S pretreated by the plasma pretreatment device facing outward, and the film forming roller 33 performs the film forming process, and the target of the film forming source 34 arranged opposite the film forming roller is evaporated to form a deposition film on the substrate film surface.

The deposition film forming means 34 is a resistance heating type that uses aluminum metal wire as the evaporation source, and supplies oxygen to oxidize the aluminum vapor while forming an aluminum oxide deposition film on the surface of the substrate film S.

Oxygen may be supplied as a single gas or as a mixed gas with an inert gas such as argon, but it is important to adjust the amount of oxygen that generates the maximum _Al3 concentration element bond structure portion. This makes it possible to obtain a barrier film that has high gas barrier properties and excellent transparency. The amount of oxygen may be appropriately adjusted depending on factors such as the size of the device and the displacement of the pump.

In one embodiment, multiple aluminum metal wires are placed in a boat-shaped (referred to as a "boat type") deposition vessel in the axial direction of the roller 33 and heated by resistance heating. In this way, the aluminum metal material can be evaporated while reducing the amount of heat supplied, and an aluminum oxide deposition film can be formed while minimizing the thermal deformation of the substrate film S.

(Barrier Coat Layer)
The barrier coat layer formed on the inorganic oxide vapor deposition layer is a layer having gas barrier properties, and is a resin cured film formed by applying a coating film by drying and curing.

As a first embodiment of the barrier coat layer, a cured film of a hydrolysis product of a metal alkoxide and a water-soluble polymer can be used. This barrier coat layer can be formed, for example, by the following gas barrier coating film. The gas barrier coating film is a coating film that maintains gas barrier properties in a high-temperature and high-humidity environment, and is a coating film that contains at least one metal alkoxide represented by the general formula R ¹ _n M(OR ² ) _m (wherein R ¹ and R ² represent an organic group having 1 to 8 carbon atoms, M represents a metal atom, n represents an integer of 0 or more, m represents an integer of 1 or more, and n+m represents the atomic valence of M), and a water-soluble polymer, and further comprises a barrier coat composition that is polycondensed by the sol-gel method in the presence of a sol-gel catalyst, an acid, water, and an organic solvent.

In the above general formula R ¹ _n M(OR ² ) _m , R ¹ is an optionally branched alkyl group having 1 to 8 carbon atoms, preferably 1 to 5, and more preferably 1 to 4 carbon atoms, such as a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, an i-butyl group, a sec-butyl group, a t-butyl group, an n-hexyl group, and an n-octyl group.

In the above general formula R ¹ _n M(OR ² ) _m , R ² is an optionally branched alkyl group having 1 to 8 carbon atoms, more preferably 1 to 5, and particularly preferably 1 to 4 carbon atoms, such as a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, a sec-butyl group, etc. When multiple (OR ² ) groups are present in the same molecule, the (OR ² ) groups may be the same or different.

In the above general formula R ¹ _n M(OR ² ) _m , examples of the metal atom represented by M include silicon, zirconium, titanium, and aluminum.

As the alkoxide represented by the above general formula R ¹ _n M(OR ² ) _m , at least one of a partial hydrolyzate of an alkoxide and a hydrolysis condensate of an alkoxide can be used. In addition, the partial hydrolyzate of the alkoxide is not limited to one in which all of the alkoxy groups are hydrolyzed, but may be one in which one or more are hydrolyzed, or a mixture thereof. Furthermore, as the hydrolysis condensate, a dimer or more of a partially hydrolyzed alkoxide, specifically a dimer to hexamer, may be used.

In the present invention, as the alkoxide represented by the general formula R ¹ _n M(OR ² ) _m , an alkoxysilane in which M is Si can be suitably used. Suitable alkoxysilanes include, for example, tetramethoxysilane Si(OCH ₃ ) ₄ , tetraethoxysilane Si(OC ₂ H ₅ ) ₄ , tetrapropoxysilane Si(OC ₃ H ₇ ) ₄ , tetrabutoxysilane Si(OC ₄ H ₉ ) ₄ , methyltrimethoxysilane CH ₃ Si(OCH ₃ ) ₃ , methyltriethoxysilane CH ₃ Si(OC ₂ H ₅ ) ₃ , dimethyldimethoxysilane (CH ₃ ) ₂ Si(OCH ₃ ) ₂ , dimethyldiethoxysilane (CH ₃ ) ₂ Si(OC ₂ H ₅ ) ₂ , and the like. In the present invention, condensation polymers of these alkoxysilanes can also be used. Specifically, for example, polytetramethoxysilane, polytetramethoxysilane, etc. can be used.

In the present invention, as the alkoxide represented by the above general formula R ¹ _n M(OR ² ) _m , zirconium alkoxides in which M is Zr can also be suitably used. Suitable zirconium alkoxides include, for example, tetramethoxyzirconium Zr(OCH ₃ ) ₄ , tetraethoxyzirconium Zr(OC ₂ H ₅ ) ₄ , tetra-i-propoxyzirconium Zr(iso-OC ₃ H ₇ ) ₄ , tetra-n-butoxyzirconium Zr(OC ₄ H ₉ ) ₄ , and the like.

Furthermore, as the alkoxide represented by the above general formula R ¹ _n M(OR ² ) _m , titanium alkoxides in which M is Ti can also be suitably used. Suitable titanium alkoxides include, for example, tetramethoxytitanium Ti(OCH ₃ ) ₄ , tetraethoxytitanium Ti(OC ₂ H ₅ ) ₄ , tetraisopropoxytitanium Ti(iso-OC ₃ H ₇ ) ₄ , and tetra-n-butoxytitanium Ti(OC ₄ H ₉ ) ₄ .

Furthermore, as the alkoxide represented by the above general formula R ¹ _n M(OR ² ) _m , aluminum alkoxides in which M is Al can also be suitably used. Suitable aluminum alkoxides include, for example, tetramethoxyaluminum Al(OCH ₃ ) ₄ , tetraethoxyaluminum Al(OC ₂ H ₅ ) ₄ , tetraisopropoxyaluminum Al(iso-OC ₃ H ₇ ) ₄ , tetra-n-butoxyaluminum Al(OC ₄ H ₉ ) ₄ , and the like.

In the present invention, two or more of the above alkoxides may be used in combination. For example, when an alkoxysilane is mixed with a zirconium alkoxide, the toughness, heat resistance, etc. of the resulting barrier film can be improved. When an alkoxysilane is mixed with a titanium alkoxide, the thermal conductivity of the resulting gas barrier coating film is reduced, and the heat resistance is significantly improved.

The water-soluble polymer used in the present invention may be a polyvinyl alcohol resin or an ethylene-vinyl alcohol copolymer, either alone or in combination with an ethylene-vinyl alcohol copolymer. In the present invention, the use of a polyvinyl alcohol resin and/or an ethylene-vinyl alcohol copolymer can significantly improve physical properties such as gas barrier properties, water resistance, weather resistance, and the like.

As the polyvinyl alcohol-based resin, generally, one obtained by saponifying polyvinyl acetate can be used. The polyvinyl alcohol-based resin may be a partially saponified polyvinyl alcohol-based resin in which several tens of percent of acetate groups remain, a fully saponified polyvinyl alcohol in which no acetate groups remain, or a modified polyvinyl alcohol-based resin in which the OH groups have been modified, and is not particularly limited.

As the ethylene-vinyl alcohol copolymer, a saponified product of a copolymer of ethylene and vinyl acetate, i.e., a product obtained by saponifying an ethylene-vinyl acetate random copolymer, can be used. For example, it includes a partially saponified product in which several tens of mol % of acetate groups remain, to a completely saponified product in which only a few mol % of acetate groups remain, or in which no acetate groups remain, and is not particularly limited. However, from the viewpoint of gas barrier properties, it is preferable to use a saponification degree of 80 mol % or more, more preferably 90 mol % or more, and even more preferably 95 mol % or more. The content of repeating units derived from ethylene in the ethylene-vinyl alcohol copolymer (hereinafter also referred to as "ethylene content") is usually 0 to 50 mol %, preferably 20 to 45 mol %.

A silane coupling agent may also be added to the barrier coat layer. For example, a silane coupling agent having a reactive group such as an alkoxy group such as a methoxy group or an ethoxy group, an acetoxy group, an amino group, or an epoxy group may be used. Specifically, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-glycidoxypropyldimethylmethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropyldimethylethoxysilane, or β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane may be used.

Furthermore, examples of the organic solvent used in the barrier coat composition include methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, and n-butanol. The polyvinyl alcohol resin and/or ethylene-vinyl alcohol copolymer are preferably handled in a dissolved state in a coating liquid containing the alkoxide and silane coupling agent, and the organic solvent can be appropriately selected from the organic solvents listed above. For example, when a polyvinyl alcohol resin and an ethylene-vinyl alcohol copolymer are used in combination, it is preferable to use n-butanol.

The barrier coat layer can be manufactured by the following method. First, the above metal alkoxide, and optionally a silane coupling agent, a water-soluble polymer, a sol-gel catalyst, an acid, water, an organic solvent, etc. are mixed to prepare a barrier coat composition (barrier coat liquid).

Next, the barrier coat composition is applied onto the inorganic oxide vapor deposition layer. The barrier coat composition can be applied by a coating means such as roll coating using a gravure roll coater, spray coating, spin coating, dipping, brushing, bar coding, or applicator, in one or multiple applications to form a coating film with a dry thickness of 0.01 to 30 μm, preferably 0.1 to 10 μm.

Next, the film coated with the barrier coat composition is heated and dried for 3 seconds to 10 minutes at a temperature of 120°C to 200°C and below the melting point of the resin film of the substrate film of the barrier film, preferably 130°C to 180°C, more preferably 140°C to 160°C. This allows polycondensation to occur, forming a barrier coat layer. Alternatively, the barrier coat composition may be coated on top of the inorganic oxide vapor deposition layer to form two or more layers of coating film, and then heated and dried for 3 seconds to 10 minutes at a temperature of 120°C to 200°C and below the melting point of the resin substrate to form a composite polymer layer with two or more layers of barrier coat layers. This allows one or more barrier coat layers to be formed from the barrier coat composition.

The thickness of the barrier coat layer is not particularly limited, but is preferably 10 nm to 5000 nm, more preferably 50 nm to 1000 nm, even more preferably 100 nm to 500 nm, and even more preferably 150 nm to 400 nm. If the thickness of the barrier coat layer is within the above range, it can exhibit gas barrier properties and can cover the surface of the inorganic oxide deposition layer as a flexible layer.

As a second embodiment of the barrier coat layer, a resin cured film containing a reaction product formed by reacting a metal oxide with a phosphorus compound can be used. This resin cured film has gas barrier properties, and the wave number at which the infrared absorption is maximum in the infrared absorption spectrum in the range of 800 to 1400 cm-1 is in the range of 1080 to 1130 cm-1.

When a bond represented by M-O-P is formed in the reaction product, in which the metal atom (M) and phosphorus atom (P) that make up the metal oxide are bonded via an oxygen atom (O), it is believed that an absorption peak based on the M-O-P bond appears in the range of 1080 to 1130 cm-1 as an absorption peak with a maximum absorption wavenumber in the region of 800 to 1400 cm-1.

This infrared absorption spectrum can be obtained by measuring the surface of the barrier coat layer using a total reflection measurement method, or by measuring the infrared absorption spectrum of the components scraped off from the barrier coat layer using the KBr method.

Metal oxides are oxides of magnesium, calcium, aluminum, silicon, titanium, zirconium, etc.

Metal oxides can be obtained by hydrolysis of compounds containing the metal atoms. Compounds capable of producing metal oxides by hydrolysis include aluminum chloride, aluminum triethoxide, aluminum tri-normal propoxide, aluminum triisopropoxide, aluminum tri-normal butoxide, aluminum tri-s-butoxide, aluminum tri-t-butoxide, aluminum triacetate, aluminum acetylacetonate, aluminum nitrate, titanium tetraisopropoxide, titanium tetra-normal butoxide, titanium tetra(2-ethylhexoxide), titanium tetramethoxide, titanium tetraethoxide, titanium acetylacetonate, zirconium tetra-normal propoxide, zirconium tetrabutoxide, and zirconium tetraacetylacetonate. These compounds may be used alone or in combination of two or more.

Phosphorus compounds that have a structure in which a halogen atom or an oxygen atom is directly bonded to a phosphorus atom can be used. Specifically, phosphoric acid, polyphosphoric acid, phosphorous acid, phosphonic acid, and derivatives thereof are used. Examples of polyphosphoric acid include pyrophosphoric acid, triphosphoric acid, and polyphosphoric acid in which four or more phosphoric acids are condensed. Examples of derivatives include salts, (partial) ester compounds, halides (chlorides, etc.), and dehydrates (diphosphorus pentoxide, etc.) of phosphoric acid, polyphosphoric acid, phosphorous acid, and phosphonic acid.

The reaction product can be formed by mixing and reacting a metal oxide with a phosphorus compound. In this case, the phosphorus compound to be mixed may be in the form of itself or in the form of a composition containing the phosphorus compound and an additive resin.

Such additive resins include polyvinyl alcohol, partially saponified polyvinyl acetate, polyethylene glycol, polyhydroxyethyl (meth)acrylate, polyacrylic acid, polymethacrylic acid, poly(acrylic acid/methacrylic acid) and their salts, ethylene-vinyl alcohol copolymer, ethylene-maleic anhydride copolymer, styrene-maleic anhydride copolymer, isobutylene-maleic anhydride alternating copolymer, ethylene-acrylic acid copolymer, and saponified ethylene-ethyl acrylate copolymer.

In the present invention, this barrier coat layer can be laminated by coating the inorganic oxide vapor deposition layer with a coating liquid containing a mixture of a metal oxide and a phosphorus compound and drying it, and the thickness is 0.05 to 1 μm.

The coating liquid can be prepared by first dispersing and dissolving a compound capable of producing a metal oxide by hydrolysis to produce a metal oxide, and then adding the resulting aqueous solution to a solvent in which a phosphorus compound has been dispersed and dissolved, or to a solvent in which a composition containing a phosphorus compound and an additive resin has been dispersed and dissolved.

As a third embodiment of the barrier coat layer, a resin cured film containing a carboxyl group-containing polymer crosslinked with a polyvalent metal compound can be used. This resin cured film has gas barrier properties.

A carboxyl group-containing polymer is a polymer that contains two or more carboxyl groups, specifically, polyacrylic acid, polymethacrylic acid, a copolymer of acrylic acid and methacrylic acid, or a mixture of two or more of these.

The polyvalent metal compounds are metal compounds of beryllium, magnesium, calcium, titanium, zirconium, chromium, manganese, iron, cobalt, nickel, copper, zinc, and aluminum, as well as their oxides, carbonates, and organic acid salts. These oxides and carbonates include oxides such as zinc oxide, magnesium oxide, copper oxide, nickel oxide, and cobalt oxide; carbonates such as calcium carbonate; and organic acid salts such as calcium lactate, zinc lactate, and calcium acrylate. A resin film containing a carboxyl group-containing polymer crosslinked by a polyvalent metal compound can be made as a resin cured film by mixing a carboxyl group-containing polymer and a polyvalent metal compound.

In addition, another form of this resin film can be made by laminating a layer containing a polyvalent metal compound adjacent to a resin layer containing a carboxyl group-containing polymer to form a two-layer structure. The resin layer containing the carboxyl group-containing polymer is ionically crosslinked by polyvalent metal ions that have migrated from the adjacent layer containing the polyvalent metal compound to form a cured resin film.

The resin layer containing the carboxyl group-containing polymer can contain polyalcohols such as polyvinyl alcohol and glycerin, in addition to the polymer containing two or more carboxyl groups. The polymer containing two or more carboxyl groups and the polyvinyl alcohol are mixed in a weight ratio of 99:1 to 20:80.

The layer containing the polyvalent metal compound is a layer in which the above-mentioned metal compound is mixed with at least one resin selected from the group consisting of alkyd resin, melamine resin, acrylic resin, urethane resin, nitrocellulose, epoxy resin, polyester resin, phenol resin, amino resin, fluororesin, and isocyanate, which are mixed resins. The weight ratio of the polyvalent metal compound to the resin (metal compound/resin) is 0.01 to 1000. The polyvalent metal compound is mixed into the resin layer in the form of particles with an average particle size of 15 nm to 500 nm.

In the present invention, the barrier coat layer can be laminated by coating and drying an inorganic oxide vapor deposition layer with a coating liquid prepared by dispersing or dissolving a resin containing a carboxyl group-containing polymer and a polyvalent metal compound in a single or mixed solution of water, alcohols such as methyl alcohol, ethyl alcohol, isopropyl alcohol, or N,N-dimethyl sulfoxide, N,N-dimethylformamide, dimethylacetamide, acetone, methyl ethyl ketone, diethyl ether, dioxane, tetrahydrofuran, ethyl acetate, or butyl acetate, and the thickness is 0.1 to 10 μm.

As another method, a layer containing a carboxyl group-containing polymer is first laminated on the inorganic oxide vapor deposition layer. This lamination is performed by coating and drying a coating liquid in which the carboxyl group-containing polymer and other necessary additives are dissolved or dispersed in a solvent such as water, alcohols such as methyl alcohol, ethyl alcohol, isopropyl alcohol, etc., N,N-dimethyl sulfoxide, N,N-dimethylformamide, dimethylacetamide, etc., to a thickness of 0.1 to 10 μm.

Next, a coating solution in which the polyvalent metal compound and resin are dissolved or dispersed in a solvent such as acetone, methyl ethyl ketone, diethyl ether, dioxane, tetrahydrofuran, ethyl acetate, or butyl acetate is used to coat and dry a resin layer containing a carboxyl group-containing polymer, thereby laminating a layer containing the polyvalent metal compound to a thickness of 0.1 to 10 μm.

By laminating a layer containing a polyvalent metal compound on a resin layer containing a carboxyl group-containing polymer in this way, the polyvalent metal ions that have migrated from the layer containing the polyvalent metal compound crosslink the carboxyl group-containing polymer ions, forming a cured resin film. After the two layers are formed, aging may be performed in a heated environment of 30 to 130 degrees to promote the migration of the polyvalent metal ions.

<Packaging materials>
The packaging material according to the present invention comprises, in this order, a heat seal layer, an adhesive layer, and a barrier layer made of the above-mentioned barrier film. Because the packaging material of the present invention has such a layer structure, it can be suitably used as a packaging material for packaging products that require high gas barrier properties.

The layer structure of the packaging material of the present invention will be described with reference to the drawings. The packaging material 50 shown in FIG. 5 includes, in order from the outermost layer side, a substrate film 52 (outermost layer), an inorganic oxide deposition layer 53, and a barrier layer 51 (barrier film) having a barrier coat layer 54, and includes an adhesive layer 55 and a heat seal layer 56 (innermost layer) on the barrier coat layer 54 side (inner side) of the barrier layer 51 in this order. As shown in FIG. 6 and FIG. 7, the packaging material 50 may further include an intermediate layer 57 between the barrier coat layer 54 and the adhesive layer 55, or between the adhesive layer 55 and the heat seal layer 56. Furthermore, when the packaging material 50 includes the intermediate layer 57, the packaging material 50 may include an adhesive layer 55 between the barrier coat layer 54 and the intermediate layer 57, and between the intermediate layer 57 and the heat seal layer 56, as shown in FIG. 8.

The packaging material preferably has a water-exposed peel strength between the base film and the aluminum oxide vapor-deposited film measured in accordance with JIS K6854-2 of 1.0 N or more, more preferably 2.0 N or more. The water-exposed peel strength in the present invention is measured by the following method.

The tensile tester used is a Tensilon universal material testing machine manufactured by Orientec Co., Ltd. First, as shown in Fig. 9, for example, a rectangular test piece 60 is prepared in a state in which the base film 52 side and the heat seal layer 56 side (e.g., the inorganic oxide deposition layer 53, the barrier coat layer 54, the adhesive layer 55, and the heat seal layer 56) are peeled off by 15 mm in the long side direction. The width (length of the short side) of the test piece 60 is 15 mm.
Next, when viewed along the longitudinal direction of the test piece, water was dropped with a dropper onto the boundary between the part where the base film 52 and the heat seal layer 56 side remained bonded and the part where the base film 52 side and the heat seal layer 56 side had been peeled away.
Thereafter, as shown in FIG. 10, the already peeled portions of the base film 52 side and the heat seal layer 56 side are gripped by the gripper 61 and the gripper 62 of the measuring device, respectively. The grippers 61 and 62 are pulled at a speed of 50 mm/min in a direction perpendicular to the surface direction of the portion where the base film 52 side and the heat seal layer 56 side are still laminated (180° peeling: T-shaped peeling method), and the average value of the tensile stress in the stable region (see FIG. 11) is measured. When the pulling is started, the interval S between the grippers 61 and 62 is 30 mm, and when the pulling is ended, the interval S between the grippers 61 and 62 is 60 mm. FIG. 11 is a diagram showing the change in tensile stress with respect to the interval S between the grippers 61 and 62. As shown in FIG. 11, the change in tensile stress with respect to the interval S passes through the first region and enters the second region (stable region) where the change rate is smaller than that in the first region. The average value of the tensile stress in the stable region is measured, and this value is regarded as the peel strength between the substrate film and the aluminum oxide vapor-deposited film of the barrier film.

The packaging material has an acidity transmission rate of preferably 0.50 cc/ ^m2 ·atm·day or less, more preferably 0.30 cc/m2·atm·day or less, and even more preferably 0.20 cc/ ^m2 ·atm·day or less, measured in accordance with JIS K7126 under an environment of 23°C and 90% RH after moist heat sterilization treatment at ¹³⁵ °C for 40 minutes. If the oxygen transmission rate after moist heat sterilization treatment satisfies the above numerical range, the packaging material has suitable oxygen barrier properties, and therefore adverse effects on the contents of the packaging material can be suppressed even in retort packaged products.

The packaging material has a water vapor permeability measured in accordance with JIS K7129 under an environment of a temperature of 40° C. and a humidity of 100% RH after moist heat sterilization at 135° C. for 40 minutes of preferably 1.20 g/m ² ·day or less, more preferably 1.00 g/m ² ·day or less, even more preferably 0.70 g/m ² ·day or less, even more preferably 0.50 g/m ² ·day or less, and particularly preferably 0.40 g/m ² ·day or less. If the water vapor permeability after moist heat sterilization satisfies the above numerical range, the packaging material has suitable water vapor barrier properties, and therefore adverse effects on the contents of the packaging material can be suppressed even in retort packaged products.

After the packaging material is subjected to moist heat sterilization at 135°C for 40 minutes, the normal peel strength between the base film and the aluminum oxide vapor deposition film measured in accordance with JIS K6854-2 is preferably 1.0 N or more, more preferably 2.0 N or more. The normal peel strength in the present invention is measured by the following method.

As a tensile tester, a Tensilon universal material testing machine manufactured by Orientec Co., Ltd. is used. First, as shown in FIG. 12, for example, a rectangular test piece 60 is prepared in a state in which the base film 52 side and the heat seal layer 56 side (for example, the inorganic oxide deposition layer 53, the barrier coat layer 54, the adhesive layer 55, the intermediate layer 57, the adhesive layer 55 and the heat seal layer 56) are peeled off by 15 mm in the long side direction. The width (length of the short side) of the test piece 60 is 15 mm. Then, as shown in FIG. 13, the already peeled parts of the base film 52 side and the heat seal layer 56 side are gripped by the gripper 61 and the gripper 62 of the measuring device, respectively. In addition, the grippers 61 and 62 are pulled at a speed of 50 mm/min in a direction perpendicular to the surface direction of the part where the base film 52 side and the heat seal layer 56 side are still laminated (180° peeling: T-shaped peeling method), and the average value of the tensile stress in the stable region (see FIG. 11) is measured. When tension is started, the distance S between the grippers 61 and 62 is 30 mm, and when tension is stopped, the distance S between the grippers 61 and 62 is 60 mm. Figure 11 is a diagram showing the change in tensile stress with respect to the distance S between the grippers 61 and 62. As shown in Figure 11, the change in tensile stress with respect to the distance S passes through a first region and enters a second region (stable region) where the rate of change is smaller than that of the first region. The average value of the tensile stress in the stable region is measured, and this value is taken as the peel strength between the substrate film of the barrier film and the aluminum oxide vapor deposition film.

After the packaging material is subjected to moist heat sterilization at 135°C for 40 minutes, the water-exfoliation peel strength between the base film and the aluminum oxide vapor deposition film, measured in accordance with JIS K6854-2, is preferably 1.0 N or more, and more preferably 2.0 N or more. The water-exfoliation peel strength in the present invention is measured by the following method.

The water-exposed peel strength after moist heat sterilization at 135°C for 40 minutes is measured in the same manner as the method for measuring the normal peel strength after moist heat sterilization at 135°C for 40 minutes, except for the points described below. In measuring the water-exposed peel strength, the base film side and the heat seal layer side of the test piece are peeled off by 15 mm, and the peel strength of the adhesive interface between the base film side and the heat seal layer side is measured. In measuring the water-exposed peel strength, when the test piece is viewed in the longitudinal direction, water is dropped with a dropper onto the boundary between the part where the base film side and the heat seal layer side remain bonded and the part where the base film side and the heat seal layer side have been peeled off.

Each layer constituting the packaging material of the present invention will be described below. Note that the barrier layer in the packaging material is the barrier film already described in detail, so a detailed description of it will be omitted here.

(Middle class)
In the packaging material of the present invention, various resin layers or resin films can be used as an intermediate layer for imparting durability, flex resistance, etc. to the packaging material. For example, a polyester-based resin, a polyolefin-based resin, or a polyamide-based resin can be used as the intermediate layer, and it is preferable to use a polyamide-based resin. Examples of polyamide resins include nylons such as polycaproamide (nylon 6), poly-ω-aminoheptanoic acid (nylon 7), poly-9-aminononanoic acid (nylon 9), polyundecaneamide (nylon 11), polylaurinlactam (nylon 12), polyethylenediamineadipamide (nylon 2,6), polytetramethyleneadipamide (nylon 4,6), polyhexamethylenediadipamide (nylon 6,6), polyhexamethylenesebacamide (nylon 6,10), polyhexamethylenedodecamamide (nylon 6,12), polyoctamethyleneadipamide (nylon 8,6), polydecamethyleneadipamide (nylon 10,6), polydecamethylenesebacamide (nylon 10,10), polydodecamethylenedodecamamide (nylon 12,12), and metaxylenediamine-6 nylon (MXD6). In addition, nylon 6-6,6, which is a copolymer of nylon 6 and nylon 6,6, nylon 6-12, which is a copolymer of nylon 6 and nylon 6-12, and the like can also be used. By using these nylons, it is possible to impart flex resistance to the packaging material. The method for forming the intermediate layer is not particularly limited, and it can be formed by a conventionally known method. For example, the intermediate layer may be formed by extrusion molding of a resin, or a resin film may be used.

The thickness of the intermediate layer is not particularly limited, but is preferably about 5 μm to 100 μm, and more preferably about 10 μm to 50 μm.

(Heat seal layer)
In the packaging material of the present invention, a thermoplastic resin can be used as the heat seal layer. Specifically, examples of the thermoplastic resin include low-density polyethylene, medium-density polyethylene, high-density polyethylene, linear low-density polyethylene, ethylene-α-olefin copolymers polymerized using a metallocene catalyst, polypropylene, ethylene-vinyl acetate copolymers, ionomer resins, ethylene-acrylic acid copolymers, ethylene-ethyl acrylate copolymers, ethylene-methacrylic acid copolymers, ethylene-methyl methacrylate copolymers, ethylene-propylene copolymers, methylpentene polymers, polybutene polymers, polyolefin resins such as polyethylene or polypropylene, acid-modified polyolefin resins obtained by modifying these polyolefin resins with unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, and itaconic acid, polyvinyl acetate resins, poly(meth)acrylic resins, and polyvinyl chloride resins.

The heat seal layer can be formed by melt-extruding one or more of the above-mentioned thermoplastic resins using an extruder or the like onto the intermediate layer, optionally via an anchor coat layer or the like. Alternatively, the heat seal layer can be formed by previously producing a film or sheet of the above-mentioned thermoplastic resin using one or more of the above-mentioned thermoplastic resins, and then dry laminating the produced film or sheet onto the intermediate layer via a lamination adhesive layer or the like.

To obtain desired properties, the above resins can be blended with other resins. In addition, various additives, such as antioxidants, UV absorbers, antistatic agents, antiblocking agents, lubricants (fatty acid amides, etc.), flame retardants, inorganic or organic fillers, dyes, pigments, etc., can be added as desired.

The thickness of the heat seal layer is not particularly limited, but to prevent poor sealing, it is preferably about 10 μm to 300 μm, and more preferably about 20 μm to 100 μm.

(Adhesive Layer)
In the packaging material of the present invention, the packaging material may further include an adhesive layer between the barrier layer and the intermediate layer and/or between the intermediate layer and the heat seal layer. Examples of the adhesive layer include an adhesive resin layer and an adhesive layer. By including the adhesive layer in the packaging material, the laminate strength at the interface between each layer can be improved.

Thermoplastic resins that can be used for the adhesive resin layer include polyethylene-based resins, polypropylene-based resins, or cyclic polyolefin-based resins, or copolymer resins, modified resins, or mixtures (including alloys) that contain these resins as the main components. Examples of polyolefin resins include low density polyethylene (LDPE), medium density polyethylene (MDPE), high density polyethylene (HDPE), linear low density polyethylene (LLDPE), polypropylene (PP), ethylene-α-olefin copolymers polymerized using a metallocene catalyst, random or block copolymers of ethylene and polypropylene, ethylene-vinyl acetate copolymer (EVA), ethylene-acrylic acid copolymer (EAA), ethylene-ethyl acrylate copolymer (EEA), ethylene-methacrylic acid copolymer (EMAA), ethylene-methyl methacrylate copolymer (EMMA), ethylene-maleic acid copolymer, ionomer resins, and acid-modified polyolefin resins obtained by modifying the above-mentioned polyolefin resins with unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, and itaconic acid in order to improve adhesion between layers. In addition, resins obtained by graft-polymerizing or copolymerizing unsaturated carboxylic acids, unsaturated carboxylic anhydrides, and ester monomers with polyolefin resins can be used. These materials can be used alone or in combination of two or more. Examples of cyclic polyolefin resins that can be used include cyclic polyolefins such as ethylene-propylene copolymers, polymethylpentene, polybutene, and polynorbornene. These resins can be used alone or in combination of two or more.

The adhesive may be, for example, a one-component or two-component curable or non-curable vinyl, (meth)acrylic, polyamide, polyester, polyether, polyurethane, epoxy, rubber, or other solvent, water-based, or emulsion adhesive. The above-mentioned laminating adhesive may be applied to the coating surface of the layer constituting the barrier laminate by, for example, a direct gravure roll coating method, a gravure roll coating method, a kiss coating method, a reverse roll coating method, a Fontaine method, a transfer roll coating method, or other methods. The amount of application is preferably 0.1 g/ ^m2 or more and 10 g/ ^m2 or less (dry state), and more preferably 1 g/ ^m2 or more and 5 g/ ^m2 or less (dry state).

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.

<<Experiment I>>
[Examples 1-1 to 1-4], [Comparative Examples 1-1 to 1-5]
<Production of Barrier Film>
A biaxially stretched polyethylene terephthalate film having a thickness of 12 μm (hereinafter referred to as “Film I”) was prepared. Nine types of Film I were prepared with different heat shrinkage rates by adjusting the film stretch ratio, heat setting temperature after stretching, heat relaxation temperature, water content and degree of polymerization of the PET film.

(Formation of inorganic oxide vapor deposition layer)
The surface of each film I on which the inorganic oxide vapor deposition layer was to be formed was subjected to plasma pretreatment, and then a 12 nm-thick aluminum oxide vapor deposition film (inorganic oxide vapor deposition layer) was formed on the plasma-treated surface using a reactive resistance heating method as the heating means for the vacuum vapor deposition method under the following conditions to obtain a PET film (hereinafter referred to as "film II").
(Aluminum oxide film formation conditions)
Degree of vacuum: 8.1×10 ⁻² Pa

(Formation of Barrier Coat Layer)
Further, a hydrolysis solution of composition B previously prepared was added to a mixed solution of composition A prepared according to the formulation shown in Table 1, and the mixture was stirred to obtain a colorless and transparent barrier coat composition.

Next, the barrier coat composition prepared above was coated onto the aluminum oxide vapor deposition film of each film II by the direct gravure method. After that, it was heated at 150°C for 60 seconds to form a barrier coat layer with a thickness of 300 nm (in a dry state), and a barrier film (hereinafter referred to as "film III") was obtained.

(Measurement of Heat Shrinkage Rate)
For each of the films I to III produced above, a test piece was prepared with a length of 20 mm and a width of 5 mm, with the MD direction of the PET film being the lengthwise direction. The prepared test piece was subjected to a thermomechanical analysis using a thermomechanical analyzer (TMA, Seiko Instruments Inc., model name: EXSTAR6000) with a load of 2.92×10 ⁶ N/m ² per unit cross-sectional area, and then held at a temperature of 20° C. for 5 minutes, then heated to 150° C. at a heating rate of 10° C./min, held at 150° C. for 10 minutes, and then cooled to 20° C. at a heating rate of 10° C./min. The heat shrinkage rate (%) of the PET film in the MD direction was then measured. The measurement results are shown in Table 2.

(Measurement of water vapor permeability)
For each of the films II to III produced above, the water vapor permeability (g/m2·day) was measured in accordance with JIS K7129 under the measurement conditions of 40° C. and 100% RH using a water vapor permeability measuring device (a measuring device manufactured by MOCON [model name: PERMATRAN ^3/33 ]) with the sensor side set to be the base film side of the barrier film. The measurement results are shown in Table 2.

(Oxygen permeability measurement)
For each of the films II to III produced above, the oxygen permeability (cc/m2·atm·day) was measured using an oxygen permeability measuring device (manufactured by Modern Control (MOCON) [model name: OX-TRAN ^2/21 ]) in accordance with JIS K7126 under the measurement conditions of 23°C and 90% RH atmosphere, with the film set so that the oxygen supply side was the substrate film surface of the barrier film. The measurement results are shown in Table 2.

From the results in Table 2, regardless of the thermal shrinkage rate values of Film I, which is the stretched polyester film alone, and Film II before the formation of the barrier coat layer, Film III after the formation of the barrier coat layer had improved oxygen permeability compared to Film II before the formation of the barrier coat layer.
Furthermore, in films II having a heat shrinkage rate of 0.75% or less, film III after the formation of the barrier coat layer had an improved water vapor permeability compared to film II, but in films II having a heat shrinkage rate of more than 0.75%, film III had a deteriorated water vapor permeability compared to film II. The reason for this is that in films II having a heat shrinkage rate of more than 0.75%, the inorganic oxide vapor deposition layer and the barrier coat layer cannot follow the thermal shrinkage of the base film when the barrier coat layer is dried at 150° C., causing slight peeling at the interface between the base film and the inorganic oxide vapor deposition layer and causing fine cracks in the inorganic oxide vapor deposition layer and the barrier coat layer, which is thought to result in a decrease in the barrier function against water, whose molecules are smaller than oxygen.

<Production of packaging materials>
A non-axially oriented polypropylene film (CPP, thickness 70 μm) was laminated, via an adhesive, on the barrier coat layer of each of the barrier films (film III) of Examples 1-1 to 1-4 obtained above to obtain a packaging material (layer structure: base film/aluminum oxide vapor-deposited film/barrier coat layer/adhesive layer/CPP film (heat seal layer)).

The water vapor permeability and oxygen permeability of the obtained packaging materials of Examples 1-1 to 1-4 were measured in the same manner as the measurement of the barrier film. In all cases, the water vapor permeability was 0.5 g/ ^m2 ·day or less, and the oxygen permeability was 0.5 cc/ ^m2 ·atm·day or less.

<<Experiment II>>
[Example 2-1]
<Formation of Aluminum Oxide Vapor Deposition Film>
First, a roll of a 12 μm-thick biaxially oriented polyethylene terephthalate film (film I) derived from fossil fuels was prepared as a base film.
Next, a continuous vapor deposition film formation apparatus in which a pretreatment section equipped with an oxygen plasma pretreatment device was placed and a film formation section were separated was used on the surface of this film I on which the inorganic oxide vapor deposition layer was to be formed. In the pretreatment section, plasma was introduced from a plasma supply nozzle under the conditions described below, and oxygen plasma pretreatment was performed at a transport speed of 400 m/min. In the film formation section, which was continuously transported, a 12 nm-thick aluminum oxide vapor deposition film (inorganic oxide vapor deposition layer) was formed on the oxygen plasma-treated surface on film I (film II) using a reactive resistance heating method as the heating means for the vacuum vapor deposition method under the conditions described below.
(Oxygen plasma pretreatment conditions)
Plasma intensity: 200 W·sec/ ^m2
Plasma formation gas ratio: oxygen/argon = 2/1
Voltage applied between pretreatment drum and plasma supply nozzle: 340 V
Pretreatment pressure: 3.8 Pa
(Aluminum oxide film formation conditions)
Degree of vacuum: 8.1×10 ⁻² Pa
Conveying speed: 400 m/min
Oxygen gas supply amount: 20,000 sccm

<Formation of Barrier Coat Layer>
385 g of water, 67 g of isopropyl alcohol, and 9.1 g of 0.5N hydrochloric acid were mixed and adjusted to a pH of 2.2. 175 g of tetraethoxysilane as a metal alkoxide and 9.2 g of 3-glycidoxypropyltrimethoxysilane as a silane coupling agent were mixed into the solution while cooling to 10° C., to prepare solution C.
Solution D was prepared by mixing 14.7 g of polyvinyl alcohol having a polymerization degree of 2,400 and a saponification degree of 99% or more as a water-soluble polymer, 324 g of water, and 17 g of isopropyl alcohol.
The solution obtained by mixing the solutions C and D in a weight ratio of 6.5:3.5 was used as a barrier coat composition.
The above prepared barrier coat composition was coated on the aluminum oxide vapor deposition film of Film II by spin coating.
Thereafter, the film was heated in an oven at 180° C. for 60 seconds to form a barrier coat layer having a thickness of about 400 nm on the aluminum oxide vapor-deposited film, thereby obtaining a barrier film (Film III).

[Example 2-2]
A barrier film (film III) was obtained in the same manner as in Example 2-1, except that in the oxygen plasma pretreatment, the plasma intensity was changed to 100 W·sec/ ^m2 .

[Example 2-3]
A barrier film (film III) was obtained in the same manner as in Example 2-1, except that a 12 μm-thick biomass-derived PET film was used as the base film and that the plasma intensity in the oxygen plasma pretreatment was changed to 150 W·sec/ ^m2 .
The biomass-derived PET film was obtained by the following method.

83 parts by mass of terephthalic acid and 62 parts by mass of biomass ethylene glycol (manufactured by India Glycol) were fed as a slurry to a reaction vessel, and an esterification reaction was carried out at 240°C for 5 hours by a conventional direct polymerization method. Then, 0.013 parts by mass of trimethyl phosphate (manufactured by Aldrich) was added (15 mmol% relative to the acid component), and the mixture was then transferred to a polymerization reaction under high-temperature vacuum conditions. First, the vacuum degree was raised to 4000 Pa and the polymerization temperature to 280°C in 40 minutes, and then the vacuum degree was lowered to 200 Pa while maintaining the polymerization temperature at 280°C to carry out a melt polymerization reaction. The reaction time was 3 hours. The synthesized polymer was discharged in the form of a strand into running water and pelletized by a pelletizer. The pellets were dried at 160°C for 5 hours, and then solid-phase polymerized at 205°C under a nitrogen atmosphere and a vacuum of 50 Pa to obtain a polymer with an intrinsic viscosity of 0.8 dl/g. The intrinsic viscosity was calculated from the melt viscosity measured at 35°C using a phenol/tetrachloroethane (component ratio: 3/2) solvent. Differential thermal analysis of the obtained polymer (apparatus: Shimadzu DSC-60, measurement conditions: in helium gas, heating at 6°C/min) showed a glass transition temperature of 69°C, which was equivalent to that of known polyethylene terephthalate obtained from raw materials derived from fossil fuels. Radiocarbon measurement of the obtained biomass-derived polyethylene terephthalate was also performed, and the biomass degree as measured by radiocarbon (C14) was 31.25%.
Then, 60 parts by mass of the obtained polyethylene terephthalate, 30 parts by mass of recycled PET (lost parts during the manufacturing process such as ear loss during film formation were repelletized), and 10 parts by mass of a fossil fuel-derived polyethylene terephthalate master batch containing 200 ppm of porous silica having an average particle size of 0.9 μm as a lubricant were dried and fed to an extruder, melted at 285 ° C., extruded into a sheet from a T-die, and cooled and solidified with a cooling roll to obtain an unstretched sheet. Then, this unstretched sheet was stretched at a ratio of 3.5 times in the longitudinal direction with a low-speed driving roll speed of 6.5 m / min and a high-speed driving roll speed of 22 m / min, and further stretched at a ratio of 3.5 times in the transverse direction with a tenter to obtain a biaxially stretched PET film (biomass degree: 18.8%) having a thickness of 12 μm.

[Example 2-4]
A barrier film (film III) was obtained in the same manner as in Example 2-1, except that a 12 μm-thick polybutylene terephthalate film (hereinafter, PBT film) derived from fossil fuels was used as the substrate film, the thickness of the aluminum oxide vapor deposition film was changed to 10 nm, and the plasma intensity in the oxygen plasma pretreatment was changed to 150 W·sec/ ^m2 .

[Example 2-5]
A barrier film (film III) was obtained in the same manner as in Example 2-1, except that a 12 μm-thick PET film derived from fossil fuels, which had an increased moisture content due to long-term storage under high humidity, was used, and the thickness of the aluminum oxide vapor-deposited film was changed by 14 nm.

[Example 2-6]
A barrier film was obtained in the same manner as in Example 2-1, except that the thickness of the aluminum oxide vapor-deposited film was changed by 10 nm.

[Example 2-7]
A barrier film (film III) was obtained in the same manner as in Example 2-1, except that the thickness of the aluminum oxide vapor-deposited film was changed by 14 nm.

[Example 2-8]
A barrier film (film III) was obtained in the same manner as in Example 2-3, except that the thickness of the aluminum oxide vapor deposition film was changed by 10 nm.

[Example 2-9]
A barrier film (film III) was obtained in the same manner as in Example 2-3, except that the thickness of the aluminum oxide vapor deposition film was changed by 14 nm.

[Example 2-10]
A barrier film (Film III) was obtained in the same manner as in Example 2-1, except that the oxygen plasma pretreatment was not performed.

[Comparative Example 2-1]
In the oxygen plasma pretreatment, the oxygen plasma pretreatment was performed in the same manner as in Example 2-1, except that the plasma formation gas ratio was oxygen/argon = 4/1. The plasma discharge was not stable, and the oxygen plasma pretreatment could not be performed.

[Comparative Example 2-2]
In the oxygen plasma pretreatment, the oxygen plasma pretreatment was performed in the same manner as in Example 2-1, except that the pretreatment pressure was set to 50 Pa. The plasma discharge was not stable, and the oxygen plasma pretreatment could not be performed.

[Reference Example 2-1]
In the oxygen plasma pretreatment, the oxygen plasma pretreatment was performed in the same manner as in Example 2-1, except that the plasma intensity was set to 1200 W·sec/m ^2. The PET foam became discolored.

The conditions for Examples 2-1 to 2-10, Comparative Examples 2-1 to 2-2, and Reference Example 2-1 are shown in Table 3.

<Measurement method for evaluation items>
The barrier films (films III) having the barrier coat layers produced under the conditions shown in the above Examples 2-1 to 2-10 were used as samples for measurement, and the thermal shrinkage rate, the transformation rate of the transition region of the deposition film, the oxygen permeability, the water vapor permeability, and the adhesion were measured using the following methods. The evaluation results are shown in Table 4.
In addition, the color of Example 2-1 and Reference Example 2-1 in which the PET film was colored were measured. The evaluation results are shown in Table 5.
For Comparative Examples 2-1 and 2-2, the oxygen plasma pretreatment could not be performed, and therefore the above evaluation items were not measured.

(Measurement of Heat Shrinkage Rate)
A test piece was prepared for the barrier film (film III) with a length of 20 mm and a width of 5 mm, with the MD direction of the PET film being the lengthwise direction. The prepared test piece was subjected to a thermomechanical analysis using a thermomechanical analyzer (TMA, Seiko Instruments Inc., model name: EXSTAR6000) with a load of 2.92×10 ⁶ N/m ² per unit cross-sectional area, and then held at 20° C. for 5 minutes, heated to 150° C. at a heating rate of 10° C./min, held at 150° C. for 10 minutes, and then cooled to 20° C. at a heating rate of 10° C./min. The heat shrinkage rate (%) of the PET film in the MD direction was then measured.

(Metamorphic rate in the transition region)
The transformation rate of the transition region of the vapor-deposited film was measured by time-of-flight secondary ion mass spectrometry (TOF-SIMS) while repeatedly soft-etching the barrier coat layer surface of the barrier film (film III) at a constant rate with a Cs (cesium) ion gun, and measuring ions derived from the barrier coat layer, inorganic oxide vapor-deposited layer, and base film, to obtain the graph analysis diagram shown in Figure 2. Here, the unit of the vertical axis of the graph (intensity) is the intensity of the measured ions, and the unit of the horizontal axis (cycle) is the number of etching cycles.
The time-of-flight secondary ion mass spectrometer used in the TOF-SIMS was a TOF.SIMS5 manufactured by ION TOF, Inc., and the measurements were performed under the following measurement conditions.

(TOF-SIMS measurement conditions)
Primary ion type: _Bi3 ⁺⁺ (0.2 pA, 100 μs)
Measurement area: 150 x 150 ^μm2
Etching gun type: Cs (1 keV, 60 nA)
Etching area: 600 x 600 ^μm2
Etching rate: 3 sec/Cycle
In addition, in order to measure the ions derived from aluminum oxide, which is the target of measurement, it is necessary to select an ion gun that has sufficient strength to distinguish between the ions derived from aluminum oxide and ions derived from other components, and in particular to obtain a depth distribution that can be approximately converted into the concentration distribution of the _elemental bond _Al2O4H . Therefore, Cs ions were selected.

Using Cs, etching is performed from the top surface of the barrier coat layer, and analysis is performed on elemental bonds at the interface between the barrier coat layer, the aluminum oxide vapor deposition film, and the base film such as polyester film, and elemental bonds of the vapor deposition film, and graphs of the measured elements and elemental bonds are obtained.In the graph, the position where the strength of _SiO2 (mass number 59.96), which is a constituent element of the barrier coat layer, is half that of the barrier coat layer is taken as the interface between the barrier coat layer and the aluminum oxide vapor deposition film, and the position where the strength of the layer part of _C6 (mass number 72.00), which is a constituent material of the base film, is half that of the base film is taken as the interface between the barrier coat layer and the aluminum oxide vapor deposition film, and the portion from the first interface to the second interface is taken as the aluminum oxide vapor deposition film.
Next, a peak is obtained in a graph representing the measured element bond Al ₂ O ₄ H (mass number 118.93), and the region from the peak to the interface is defined as a transition region, which can be obtained.
However, when the barrier coat layer is made of a material having the same mass number as Al ₂ O ₄ H (mass number 118.93), it is necessary to separate the waveform of 118.93.
In this case, the reactants _AlSiO4 and hydroxide _Al2O4H are generated at the interface between the barrier coat layer and the aluminum oxide vapor deposition film, so they are separated from _{the Al2O4H} present at the _film interface. This is done appropriately depending on the material of the barrier coat layer.
An example of a method for waveform separation is shown below: A profile of mass number 118.93 obtained by TOF-SIMS is subjected to nonlinear curve fitting using a Gaussian function, and overlapping peaks are separated using the least squares Levenberg Marquardt algorithm.
By carrying out the above operations, the transformation rate of the transition region of the aluminum oxide vapor-deposited film was calculated as (transition region thickness from the peak of elemental bond Al ₂ O ₄ H to the interface/aluminum oxide vapor-deposited film thickness)×100(%).

(Oxygen permeability measurement)
Using an oxygen permeability measuring device (manufactured by Modern Control (MOCON) [model name: OX-TRAN 2/21]), a packaging material prepared for the measurement was prepared as barrier film/adhesive/nylon film 15 μm/adhesive/CPP 70 μm, and the above test sample was set so that the oxygen supply side was the base film surface of the barrier film, and measurement was performed in accordance with JIS K7126 Method B under measurement conditions of an atmosphere of 23° C. and 90% RH.
As a measurement sample,
1) Composite laminate film before retort treatment; 2) High retort treatment conditions: packaging material on one side of a bag of packaging material treated at 135°C for 40 minutes in a bag state; 3) Semi-retort treatment conditions: packaging material on one side of a bag of packaging material treated at 121°C for 40 minutes in a bag state was used.

(Measurement of water vapor permeability)
Using a water vapor permeability measuring device (a measuring device manufactured by MOCON [model name: PERMATRAN 3/33]), the above test sample was set so that the sensor side faced the substrate film side of the barrier film, and measurement was performed in accordance with JIS K7126 Method B under measurement conditions of 40°C and 100% RH atmosphere.
As a measurement sample,
1) Packaging material before retort treatment; 2) High retort treatment conditions: Packaging material on one side of a bag of packaging material that has been treated at 135°C for 40 minutes in a bag state; 3) Semi-retort treatment conditions: The packaging material on one side of a bag of packaging material that has been treated at 121°C for 40 minutes in a bag state was used.

(Evaluation of adhesion between substrate and aluminum oxide vapor deposition film)
[Measurement of peel strength (1): Normal peel strength after retort treatment]
A two-component curing polyurethane adhesive was applied to the barrier coat layer side of the barrier film (Film III) and dried, and this was dry laminated with a 70 μm thick unstretched polypropylene film, to which the two-component curing polyurethane adhesive and a 15 μm thick stretched nylon film were attached, to produce a packaging material.
100 mL of water was poured into a square pouch made to B5 size using the above packaging material, and hot water retort treatment (high retort treatment) was performed at 135°C for 40 minutes. After the retort treatment, the water in the contents of the square pouch was removed and cut into a 15 mm wide strip to prepare a sample. The peel strength between the substrate film of the barrier film and the aluminum oxide vapor deposition film was measured for this sample using a tensile tester (manufactured by Orientec Co., Ltd. [model name: Tensilon universal material testing machine]) in accordance with JIS K6854-2. Note that, for Example 2-4, hot water retort treatment (semi-retort treatment) was performed at 121°C for 40 minutes.
For the measurement, a rectangular test piece was prepared in a state in which the base film side and the non-stretched polypropylene film side were peeled off by 15 mm in the long side direction. Then, the already peeled parts of the base film side and the non-stretched polypropylene film side were gripped by the gripper and gripper of the measuring device, respectively. In addition, the grippers were pulled at a speed of 50 mm/min in opposite directions (180° peeling: T-shaped peeling method) in a direction perpendicular to the surface direction of the part where the base film side and the non-stretched polypropylene film side are still laminated, and the average value of the tensile stress in the stable region was measured. The distance between the grippers when the pulling started was 30 mm, and the distance between the grippers when the pulling ended was 60 mm. The change in the tensile stress with respect to the distance passed through the first region and entered the second region (stable region) where the rate of change was smaller than that of the first region. The average value of the tensile stress in the stable region was measured, and the value was taken as the peel strength between the base film of the barrier film and the aluminum oxide vapor deposition film.

[Measurement of peel strength (2): Water-soaked peel strength after retort treatment]
The water-exposed peel strength was measured in the same manner as the method for measuring the normal peel strength, except for the following points. In the measurement of the water-exposed peel strength, the base film side and the non-stretched polypropylene film side of the test piece were peeled off by 15 mm, and the peel strength of the adhesive interface between the base film side and the non-stretched polypropylene film side was measured. In the measurement of the water-exposed peel strength, when the peel strength was measured, water was dropped with a dropper onto the boundary between the part where the base film side and the non-stretched polypropylene film side maintained their bonding and the part where the base film side and the non-stretched polypropylene film side were peeled off when viewed along the longitudinal direction of the test piece.

(Color measurement)
Using a spectrophotometer (manufactured by Konica Minolta, Inc. [model name: CM-700d]), the L* value, a ^* value, and b ^* value in the L ^* a ^* b ^* color system of one measurement sample (substrate film/aluminum oxide vapor deposition ^film /barrier coat layer) were measured.

As shown in Examples 2-1 to 2-9 in Table 4 above, the barrier films in which the conversion rate in the transition region of the aluminum oxide vapor-deposited film was 5% or more and 60% or less exhibited good oxygen permeability and water vapor permeability even after retort treatment, and also showed good normal adhesion and water-resistant adhesion.
In the above Table 4, in Example 2-10, the peak of the elemental bond Al ₂ O ₄ H was too small to be separated and was hidden on the interface side of the base film, so that the conversion rate of the transition region could not be calculated (a value of 0% or less). Although Example 2-10 was inferior to Examples 2-1 to 2-9 in normal adhesion and water-resistant adhesion after retort, no deterioration in barrier property was observed before and after retort treatment.
Furthermore, in Table 5 above, since the b ^* value of Example 2-1 is lower than that of Reference Example 2-1, it is understood that Example 2-1 is more excellent in transparency than Reference Example 2-1.

<<Experiment III>>
[Example 3-1]
First, a roll of a 12 μm-thick biaxially oriented polyethylene terephthalate film (film I) derived from fossil fuels was prepared as a base film.
Next, a continuous vapor deposition film formation apparatus in which a pretreatment section equipped with an oxygen plasma pretreatment device was placed and a film formation section were separated was used on the surface of this film I on which the inorganic oxide vapor deposition layer was to be formed. In the pretreatment section, plasma was introduced from a plasma supply nozzle under the conditions described below, and oxygen plasma pretreatment was performed at a transport speed of 400 m/min. In the film formation section, which was continuously transported, a 12 nm-thick aluminum oxide vapor deposition film (inorganic oxide vapor deposition layer) was formed on the oxygen plasma-treated surface on film I (film II) using a reactive resistance heating method as the heating means for the vacuum vapor deposition method under the conditions described below.
(Oxygen plasma pretreatment conditions)
Plasma intensity: 150 W·sec/ ^m2
Plasma formation gas ratio: oxygen/argon = 2/1
Voltage applied between pretreatment drum and plasma supply nozzle: 340 V
Pretreatment pressure: 3.8 Pa
(Aluminum oxide film formation conditions)
Degree of vacuum: 8.1×10 ⁻² Pa
Conveying speed: 400 m/min
Oxygen gas supply amount: 8000 sccm

<Formation of Barrier Coat Layer>
Solution E was prepared by mixing 226 g of water, 39 g of isopropyl alcohol, and 5.3 g of 0.5N hydrochloric acid and adjusting the pH of the solution to 2.2, and then mixing 167 g of tetraethoxysilane into the solution while cooling the solution to 10°C.
Solution F was prepared by mixing 23.3 g of polyvinyl alcohol having a polymerization degree of 2,400 and a saponification degree of 99% or more, 513 g of water, and 27 g of isopropyl alcohol.
The E and F solutions were mixed in a weight ratio of 4.4:5.6 to obtain a solution which was used as a barrier coat composition.
The above prepared barrier coat composition was coated on the aluminum oxide vapor deposition film of Film II by spin coating.
Thereafter, the film was heated in an oven at 180° C. for 60 seconds to form a barrier coat layer having a thickness of about 400 nm on the aluminum oxide vapor-deposited film, thereby obtaining a barrier film (Film III).

[Example 3-2]
A barrier film (film III) was obtained in the same manner as in Example 3-1, except that in the deposition of aluminum oxide, the oxygen supply amount was changed to 10,000 sccm.

[Example 3-3]
A barrier film (Film III) was obtained in the same manner as in Example 3-1, except that the oxygen plasma pretreatment was not performed.

[Examples 3-4]
A barrier film (film III) was obtained in the same manner as in Example 3-1, except that the above biomass-derived PET film having a thickness of 12 μm was used as the base film and that the plasma intensity in the oxygen plasma pretreatment was changed to 250 W·sec/ ^m2 .

[Comparative Example 3-1]
In the oxygen plasma pretreatment, the oxygen plasma pretreatment was performed in the same manner as in Example 3-1, except that the plasma formation gas ratio was oxygen/argon = 5/1. The plasma discharge was not stable, and the oxygen plasma pretreatment could not be performed.

[Reference Example 3-1]
A barrier film (film III) was obtained in the same manner as in Example 3-1, except that in the deposition of aluminum oxide, the oxygen supply amount was changed to 20,000 sccm.

[Reference Example 3-2]
A barrier film (film III) was obtained in the same manner as in Example 3-1, except that the oxygen supply amount in the deposition of aluminum oxide was changed to 6000 sccm. The aluminum oxide vapor-deposited film was colored.

The conditions for Examples 3-1 to 3-4, Comparative Example 3-1, and Reference Examples 3-1 to 3-2 are shown in Table 6.

The barrier films (films III) having the barrier coat layers produced under the conditions shown in the above Examples 3-1 to 3-4 were used as samples for measurement, and the thermal shrinkage rate, the strength ratio _Al3 / _Al2O3 in TOF- _SIMS , the oxygen permeability, the water vapor permeability, and the adhesion were measured by the following methods. The evaluation results are shown in Table 7.
Furthermore, for the barrier films (film III) of Example 3-1 and Reference Example 3-1, the total light transmittance and haze were measured by the following methods. The evaluation results are shown in Table 7.
Furthermore, the color of the above-mentioned Examples 3-1 and 3-4, and the above-mentioned Reference Example 3-2 in which the PET film was colored, was measured. The evaluation results are shown in Table 8.
For Comparative Example 3-1, the above evaluation items were not measured because oxygen plasma pretreatment could not be performed.

(Measurement of Heat Shrinkage Rate)
A test piece was prepared for the barrier film (film III) with a length of 20 mm and a width of 5 mm, with the MD direction of the PET film being the lengthwise direction. The prepared test piece was subjected to a thermomechanical analysis using a thermomechanical analyzer (TMA, Seiko Instruments Inc., model name: EXSTAR6000) with a load of 2.92×10 ⁶ N/m ² per unit cross-sectional area, and then held at 20° C. for 5 minutes, heated to 150° C. at a heating rate of 10° C./min, held at 150° C. for 10 minutes, and then cooled to 20° C. at a heating rate of 10° C./min. The heat shrinkage rate (%) of the PET film in the MD direction was then measured.

(Intensity ratio Al ₃ /Al ₂ O ₃ in TOF-SIMS)
For the above barrier film (Film III), mass analysis was performed using a time-of-flight secondary ion mass spectrometer (ION TOF, TOF.SIMS5) under the following measurement conditions from the barrier coat layer side of the barrier film while repeatedly soft etching at a constant rate with a Cs (cesium) ion gun to measure C ₆ (mass number 72.00) derived from the base film, Al ₃ (mass number 80.94) and Al ₂ O ₃ (mass number 101.94) derived from the aluminum oxide vapor deposition film, and SiO ₂ (mass number 59.96) ions derived from the barrier coat layer.
First, the position where the strength of _SiO2 , a constituent element of the barrier coat layer, is half that of the barrier coat layer was defined as the interface between the barrier coat layer and the aluminum oxide vapor-deposited film, and then the position where the strength of the layer portion of _C6 , a constituent material of the base film, is half that of the barrier coat layer was defined as the interface between the base film and the aluminum oxide vapor-deposited film, and the area from the first interface to the second interface was defined as the aluminum oxide vapor-deposited film.
Then, the position where the strength of _Al3 was the highest in the aluminum oxide vapor-deposited film was determined, and from the strength ratio _Al3 / _Al2O3 of _{the strength of Al3 to Al2O3 at that position, the strength ratio Al3/Al2O3 at which the strength of Al3} was maximum and the proportion of that depth to the thickness of the aluminum oxide vapor _- deposited film were calculated.

(TOF-SIMS measurement conditions)
Primary ion type: _Bi3 ⁺⁺ (0.2 pA, 100 μs)
Measurement area: 150 x 150 ^μm2
Etching gun type: Cs (1 keV, 60 nA)
Etching area: 600 x 600 ^μm2
Etching rate: 10 sec/Cycle

(Oxygen permeability measurement)
Using an oxygen permeability measuring device (manufactured by Modern Control (MOCON) [model name: OX-TRAN 2/21]), the substrate film side of the barrier film (Film III) was set to be the oxygen supply side, and the oxygen permeability was measured in an atmosphere of 23°C and 90% RH in accordance with JIS K 7126 Method B.

(Measurement of water vapor permeability)
Using a water vapor transmission rate measuring device (a measuring device manufactured by MOCON [model name: PERMATRAN 3/33]), the base film layer side of the barrier film (Film III) was set to face the sensor side, and the water vapor transmission rate was measured in an atmosphere of 40° C. and 100% RH in accordance with JIS K 7126 Method B.

(Measurement of total light transmittance)
Using an optical measuring device (a measuring device manufactured by Suga Test Instruments Co., Ltd. [model name: haze meter]), the barrier film having a barrier coat layer (Film III) was set so that the base film side faced the light source side, and measurement was performed in accordance with JIS K7136.

(Haze Measurement)
Using an optical measuring device (a measuring device manufactured by Suga Test Instruments Co., Ltd. [model name: haze meter]), the barrier film having a barrier coat layer (Film III) was set so that the base film side faced the light source side, and measurement was performed in accordance with JIS K7136.

(Evaluation of adhesion between substrate film and aluminum oxide vapor deposition film)
[Measurement of peel strength: Water-soaked peel strength]
A two-component curing polyurethane adhesive was applied to the barrier coat layer side of the barrier film (Film III), which was then dried and dry laminated with a 70 μm-thick unstretched polypropylene film to prepare a packaging material.
For the measurement, first, a rectangular test piece was prepared in which the base film side and the unstretched polypropylene film side were peeled off by 15 mm in the long side direction.
Next, when viewed along the longitudinal direction of the test piece, water was dropped using a dropper onto the boundary between the area where the base film side and the unstretched polypropylene film side remained bonded and the area where the base film side and the unstretched polypropylene film side had been peeled away.
Thereafter, the already peeled portions of the base film side and the non-stretched polypropylene film side were gripped by the gripper and gripper of the measuring device, respectively. The grippers were pulled in opposite directions (180° peeling: T-shaped peeling method) perpendicular to the surface direction of the portion where the base film side and the non-stretched polypropylene film side are still laminated, at a speed of 50 mm/min, and the average value of the tensile stress in the stable region was measured. The distance between the grippers when the pulling started was 30 mm, and the distance between the grippers when the pulling ended was 60 mm. The change in the tensile stress with respect to the distance passed through the first region and entered a second region (stable region) where the rate of change was smaller than that in the first region. The average value of the tensile stress in the stable region was measured, and the value was taken as the peel strength between the base film of the barrier film and the aluminum oxide vapor deposition film.

(Color measurement)
Using a spectrophotometer (manufactured by Konica Minolta, Inc. [model name: CM-700d]), the L* value, a ^* value, and b ^* value in the L ^* a ^* b ^* color system of one measurement sample (substrate film/aluminum oxide vapor deposition ^film /barrier coat layer) were measured.

As shown in Table 7, the strength ratio _Al3 / _Al2O3x100 at the maximum _Al3 concentration element bond structure portion was 1 to 20 for Examples _3-1 to 3-4, the maximum _Al3 concentration element bond structure portion was present at a depth position of 4 to 45% of the thickness of the aluminum oxide vapor deposition film, and the oxygen permeability and water vapor permeability were low, showing good gas barrier properties. Moreover, Examples 3-1, 3-2, and 3-4, which were subjected to oxygen plasma pretreatment, showed stronger water-resistant adhesion between the aluminum oxide vapor deposition film and the substrate film than Example 3-3, which was not subjected to oxygen plasma pretreatment.
The barrier films of Examples 3-1 to 3-4 had better gas barrier properties than Reference Example 3-1 in which the strength ratio Al ₃ /Al ₂ O ₃ ×100 in the maximum Al ₃ concentration element bond structure portion was less than 1.
In addition, in Table 8 above, the L ^* values of Examples 3-1 and 3-4 are higher than that of Reference Example 3-2, and the b ^* values are lower than that of Reference Example 3-2. This shows that Examples 3-1 and 3-4 are more transparent than Reference Example 3-2.
Furthermore, since no coloring of aluminum oxide was confirmed, the barrier films of Examples 3-1 to 3-4 have better printability than the barrier film of Reference Example 3-2.

11 Barrier film 12 Substrate film 13 Inorganic oxide deposition layer 14 Barrier coat layer S Substrate film P Plasma 20 Roller type continuous deposition film forming apparatus 22 Decompression chamber 22A Substrate transport chamber 22B Plasma pretreatment chamber 22C Film formation chamber 24a-d Guide roll 28 Raw material gas volatilization supply device 30 Pretreatment roller 31 Magnet 32a-d Plasma supply nozzle 33 Film formation roller 34 Deposition film formation means 41 Power supply wiring 42 Power sources 45a-45c Partition wall 50 Packaging material 51 Barrier layer (barrier film)
52 Base film 53 Inorganic oxide deposition layer 54 Barrier coat layer 55 Adhesive layer 56 Heat seal layer 57 Intermediate layer 60 Test piece 61, 62 Grip

Claims (12)

A barrier film comprising an inorganic oxide vapor deposition layer having a barrier coat layer laminated thereon and a substrate film,
The base film is a fossil fuel-derived stretched polyester film,
the inorganic oxide vapor-deposited layer is an aluminum oxide vapor-deposited film,
In the aluminum oxide vapor deposition film, an elemental bonding structure represented by Al3 is distributed _,
when the barrier film is analyzed by time-of-flight secondary ion mass spectrometry (TOF-SIMS), the intensity ratio Al ₃ /Al ₂ O ₃ ×100 of a maximum Al ₃ concentration element bond structure portion in an aluminum oxide vapor deposition film is 1 or more and 20 or less;
the maximum Al3 _{concentration} element bond structure portion is present at a depth position of 4% to 45% of the thickness of the aluminum oxide vapor-deposited film from the surface of the aluminum oxide vapor-deposited film opposite to the substrate film,
The barrier film is subjected to a load of 2.92 x ¹⁰⁶ N/ ^m2 per unit cross-sectional area while being held at a temperature of 20°C for 5 minutes, then heated to 150°C at a heating rate of 10°C/min, held at 150°C for 10 minutes, and then cooled to 20°C at a heating rate of 10°C/min, and the heat shrinkage rate of the barrier film in the MD direction measured after the temperature is increased is 0% or more and 0.70% or less. The barrier film according to claim 1, wherein the substrate film is a biaxially oriented polyethylene terephthalate film. The barrier film according to claim 1 or 2, wherein the barrier coat layer is a resin cured film of a metal alkoxide and a water-soluble polymer. The barrier film according to claim 1 or 2, wherein the barrier coat layer is a cured resin film containing a reaction product formed by reacting a metal oxide with a phosphorus compound. The barrier film according to claim 1 or 2, wherein the barrier coat layer is a resin cured film containing a carboxyl group-containing polymer crosslinked by a polyvalent metal compound. a transition region is formed in the aluminum oxide vapor-deposited film, the transition region defining the peel strength between the surface of the base film and the aluminum oxide vapor-deposited film;
the transition region contains elementally bound Al ₂ O ₄ H which transforms into aluminum hydroxide, as detected by etching using time-of-flight secondary ion mass spectrometry (TOF-SIMS);
6. The barrier film according to claim 1 , wherein a transformation rate of a transition region, which is defined as a ratio of the transformed transition region to the aluminum oxide vapor-deposited film, determined by etching the barrier coat layer and the aluminum oxide vapor-deposited film using TOF-SIMS, is 5 % or more and 60% or less. 7. The barrier film according to claim 1 , having an oxygen permeability of 1.0 cc/ ^m2 ·atm·day or less, measured in accordance with JIS K7126 under an environment of a temperature of 23° C. and a humidity of 90% RH. 7. The barrier film according to claim 1 , wherein the water vapor permeability measured in accordance with JIS K7129 under an environment of a temperature of 40° C. and a humidity of 100% RH is 1.0 g/ ^m2 ·day or less. A packaging material comprising the barrier film according to any one of claims 1 to 8 . The packaging material according to claim 9 , comprising, in this order, a heat seal layer, an adhesive layer, and a barrier layer made of the barrier film. A packaging material comprising the barrier film according to claim 6 ,
The packaging material has a normal peel strength of 1.0 N or more between the base film and the aluminum oxide vapor-deposited film, measured in accordance with JIS K6854-2, after moist heat sterilization at 135° C. for 40 minutes. A packaging material comprising the barrier film according to claim 6 ,
The packaging material has a water peel strength of 1.0 N or more between the base film and the aluminum oxide vapor-deposited film, measured in accordance with JIS K6854-2, after moist heat sterilization at 135° C. for 40 minutes.