Gas barrier film

Abstract

To provide a gas barrier film comprising a gas barrier layer containing silicon oxide, while exhibiting stable water vapor barrier properties.SOLUTION: A gas barrier film 1 comprises a base layer 10 and a gas barrier layer 20 formed on the base layer and containing silicon oxide. The gas barrier layer has, in an infrared absorption spectrum from the surface side, a ratio of the peak area of the absorption peak at 830 cm-1 or more and 910 cm-1 or less derived from Si-OH bonds to the peak area of the absorption peak at 720 cm-1 or more and 1320 cm-1 or less derived from Si-O-Si bonds, which is 0.025 or less.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a gas barrier film, and more particularly to a gas barrier film suitable for packaging foods, pharmaceuticals, precision electronic components, etc. The manufacturing method of this gas barrier film will also be mentioned.

Background Art

[0002] In packaging materials used for foods and pharmaceuticals, from the viewpoint of suppressing the deterioration of the contents and maintaining their functions and properties, a gas barrier property that blocks oxygen, water vapor, and other gases that deteriorate the contents and permeate through the packaging material may be required. Further, as a packaging material having a gas barrier property, a gas barrier film using a metal foil such as aluminum, which is less affected by temperature, humidity, etc., as a gas barrier layer, is known.

[0003] As another configuration of the gas barrier film, a film in which a vapor deposition film of an inorganic oxide such as silicon oxide or aluminum oxide is formed on a base film made of a polymer material by vacuum vapor deposition, sputtering, or the like is known (see, for example, Patent Document 1). These gas barrier films have transparency and gas barrier properties against oxygen, water vapor, etc.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The inventors have found that when the gas barrier layer is composed of a vapor deposition film of silicon oxide, there is a tendency for relatively large variations in water vapor barrier properties. The inventors have intensively studied to suppress this and completed the present invention.

[0006] In view of the above circumstances, an object of the present invention is to provide a gas barrier film having a gas barrier layer containing silicon oxide and having stable water vapor barrier properties.

Means for Solving the Problems

[0007] The present invention is a gas barrier film including a base material layer and a gas barrier layer formed on the base material layer and containing silicon oxide. In the infrared absorption spectrum from the surface side, the ratio of the peak area of the absorption peak at 830 cm -1 or higher and 1320 cm -1 or lower derived from the Si-OH bond to the peak area of the absorption peak at 720 cm -1 or higher and 910 cm -1 or lower derived from the Si-O-Si bond is 0.025 or less.

Effects of the Invention

[0008] According to the present invention, it is possible to provide a gas barrier film having a gas barrier layer containing silicon oxide and having stable water vapor barrier properties.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Modes for Carrying Out the Invention

[0010] Hereinafter, a first embodiment of the present invention will be described with reference to FIG. 1. Figure 1 is a schematic cross-sectional view of the gas barrier film 1 according to this embodiment. The gas barrier film 1 includes a base material layer 10 and a gas barrier layer 20 provided on one surface of the base material layer 10.

[0011] The base material layer 10 is formed of a synthetic resin. There is no particular limitation on the material of the base material layer 10, and various known materials can be used. Specific examples include polyolefins (such as polyethylene and polypropylene), polyesters (such as polyethylene terephthalate and polyethylene naphthalate), polyimides, polyamides (such as nylon-6 and nylon-66), polystyrene, ethylene vinyl alcohol, polyvinyl chloride, polyimide, polyvinyl alcohol, polycarbonate, polyethersulfone, acrylic, cellulose-based (such as triacetyl cellulose and diacetyl cellulose), etc. In practice, it is preferably selected appropriately according to the use and required physical properties. For packaging that protects contents that extremely dislike moisture, such as electronic components and optical components, it is preferable to use materials that themselves have high gas barrier properties, such as polyethylene naphthalate, polyimides, and polyethersulfone.

[0012] There is no particular limitation on the thickness of the base material layer 10, and it can be about 9 μm to 300 μm in consideration of the use and the like. The base material layer 10 with a thickness within this range has appropriate flexibility and can also be wound into a roll shape, so it is easy to handle.

[0013] The form of the base material layer 10 may be a long material or a single sheet material, but a long one can be preferably used. The length in the longitudinal direction of the long base material layer 10 is not particularly limited, but for example, a resin film of 10 m or more is preferably used. Note that the upper limit of the length is not limited, and it may be about 10 km, for example.

[0014] On the surface of the base material layer 10, additives such as an antistatic agent, an ultraviolet absorber, a plasticizer, and a lubricant may be included as necessary. Further, in order to enhance the adhesion, the surface of the base material layer 10 may be subjected to physical treatments such as corona treatment, frame treatment, plasma treatment, and easy adhesion treatment, or chemical treatment modification treatments such as chemical treatment with an acid or an alkali. The surface of the base material layer 10 contributes to the denseness in the initial growth stage of vacuum film formation when forming the gas barrier layer, and from this viewpoint, it is preferably as smooth as possible.

[0015] The gas barrier layer 20 is a layer that plays a major role in the gas barrier property exhibited by the gas barrier film 1, and is a film made of an inorganic oxide containing at least silicon oxide (SiOx).

[0016] In the gas barrier layer 20 according to the present embodiment, the ratio (O / Si) of the number of oxygen (O) atoms to the number of silicon (Si) atoms is 1.0 or more and 1.9 or less at least on the surface of the gas barrier layer 20. Considering the transparency of the entire gas barrier film 1, the O / Si is more preferably 1.3 or more. The O / Si of the gas barrier layer 20 can be measured by a known method. For example, it can be evaluated with an analyzer such as an XPS (X-ray photoelectron spectrometer). In analyzers such as XPS (X-ray photoelectron spectrometer), argon (Ar) ion sputter etching may be used for analysis in the film, but since a transparent oxide film layer containing silicon (Si) is reduced and the correct ratio (O / Si) of the number of silicon (Si) atoms to the number of oxygen (O) atoms cannot be obtained, it is desirable to analyze the surface of the layer.

[0017] There is no limitation on the method for forming the gas barrier layer 20. For example, known film forming methods such as vacuum evaporation method, ion plating method, sputtering method, and plasma chemical vapor deposition method (PECVD) can be used. However, since it has excellent productivity, the vacuum evaporation method is particularly preferable. As the material heating means of the vacuum evaporation method, a resistance heating type, a high-frequency induction heating type, an electron beam heating type, etc. can be used. Further, by combining a plasma assist method, an ion beam assist method, etc., the gas barrier layer 20 can be formed densely to improve the barrier property.

[0018] When forming the gas barrier layer 20 by vacuum deposition, the partial pressure value of m / z 18 measured by a partial pressure gauge (quadrupole mass spectrometer using a Faraday cup) during film formation is set to be 0.05 Pa or less. If the partial pressure of m / z 18 measured by the mass spectrometer during film formation exceeds 0.05 Pa, the amount of water molecules in the deposition atmosphere is large, so the amount of OH bonded to Si increases, which is not preferable. Here, m / z (specifically italicized) is defined as a dimensionless quantity obtained by dividing the mass of an ion by the unified atomic mass unit and further dividing by the absolute value of the charge number of the ion, and it is the value adopted on the horizontal axis of the mass spectrum measured by a mass spectrometer. m / z is defined as an academic term by the International Union of Pure and Applied Chemistry (IUPAC). m / z 18 refers to the m / z derived from the H 2 O + ion. As ions related to moisture, in addition to m / z 18, there are also fragment ions such as m / z 17, etc. In the present invention, m / z 18 derived from the H 2 O + ion with the strongest spectral intensity is used as an index. As a specific method for adjusting the partial pressure of m / z 18 during film formation, it is typical to provide a mechanism for adsorbing gas in the film formation environment. For example, a device for condensing and adsorbing gas (water vapor) (hereinafter, "gas adsorption device") is provided in the film formation chamber of the film formation apparatus, and further provided in the unwind / rewind chamber, particularly near the unwind roll. By both the effect of reducing the water vapor in the film formation chamber and the effect of reducing the water vapor derived from the moisture released from the substrate, the partial pressure of m / z 18 during film formation can be suppressed to 0.05 Pa or less. As the gas adsorption device, a Meissner coil, a cryopanel, a cryopump, a soap solution pump, an ion pump, and a getter pump are preferably used. Since the adsorption area can be increased, a Meissner coil and a cryopanel are more preferably used. For example, when a Meissner coil or a cryopanel is used, from the viewpoint of sufficiently obtaining the performance of condensing and adsorbing gas, the cooling temperature is preferably -100 °C or lower, and more preferably -110 °C or lower.

[0019] By adjusting the above-mentioned O / Si value and the partial pressure of m / z18 during film formation within a predetermined range, the amount of water molecules present in the atmosphere during the formation of the inorganic oxide film becomes less than that in a general vapor deposition process, and the amount of OH in the water molecules that can bind to Si also decreases. And, by reducing the amount of Si-OH bonds, the intermolecular gaps in the inorganic oxide film decrease. As a result, the gas barrier layer 20 has a dense structure, and the stability of the water vapor barrier property exhibited can be enhanced.

[0020] The above-mentioned state in the gas barrier layer 20 can be evaluated by calculating the amount of Si-OH etc. using FT-IR (Fourier transform infrared spectrophotometer) analysis. Specifically, in the infrared absorption spectrum obtained by FT-IR analysis, using the software attached to the apparatus, the peak area derived from the Si-O-Si bond (720 cm -1 ~1320 cm -1 ), and for each of the peak areas derived from the Si-OH bond (830 -1 ~910 cm -1 ), a baseline connecting the plots at both ends of the defined range is drawn, and the area of the portion surrounded by the spectrum and the baseline is calculated. At this time, the region below the baseline is ignored and not included in the area. Although FT-IR analysis is often measured by the ATR method, in the studies by the inventors, it has been found that the data before correction such as ATR correction and baseline correction more accurately reflects the properties of the gas barrier layer 20. Therefore, for the values of the parameters mentioned hereinafter, they are defined as those of the uncorrected data obtained by FT-IR analysis.

[0021] Details will be shown later using examples, ·With respect to the peak area derived from the Si-O-Si bond (720 cm -1 ~1320 cm -1 ), for the Si-OH bond (830 -1 ~910 cm -1The ratio of the peak area derived from ) is 0.025 or less, more preferably 0.016 or less. It has been clarified by the study of the inventors that serves as an index indicating that the intermolecular gaps in the gas barrier layer 20 are few and the film is dense as a film. The gas barrier film according to the present invention exhibits stable gas barrier properties by including the gas barrier layer 20 that satisfies the above index. Also, in the mass production process, the gas barrier property is stable at a high level, and a high-quality gas barrier film can be efficiently manufactured.

[0022] The chemical bonding state of the gas barrier layer 20 can also be analyzed using X-ray photoelectron spectroscopy (hereinafter sometimes referred to as "XPS"). XPS is a technique that irradiates X-rays onto the measurement target and analyzes the energy of the photoelectrons emitted from the surface of the measurement target, and can analyze the composition and chemical bonding state of elements in a region with a depth of several nm from the surface of the measurement target. The chemical bonding state related to silicon oxide in the inorganic oxide film layer 13 is SiO 2 (Si 4+ ) In addition to Si 3+ , Si 2+ , Si + It is known that three sub-oxide components of + and five of Si exist. When the narrow spectrum of Si 2p is measured by XPS, SiO 2 is observed in the vicinity of 103.5 to 104.5 eV, and Si 3+ , Si 2+ , Si + and Si are observed at positions shifted to the lower energy side than SiO 2 , each at a position separated by about 1 eV.

[0023] Also, when the narrow spectrum of Si 2p is measured using XPS with a generally used X-ray source of MgKα or AlKα and a pass energy of about 10 eV, the peaks of each bond are not separated and are observed in a synthesized form. Therefore, in the narrow spectrum of Si 2p , SiO 2In the case of the film, a peak top is detected around 103.5 to 104.5 eV, but for the silicon oxide film mainly composed of SiO and including a plurality of other chemical bonding states, the peak top shifts to the range of 101 to 103.5 eV. Also, compared with the case of the SiO film, in the case of the silicon oxide film mainly composed of SiO and including a plurality of other chemical bonding states, the full width at half maximum (FWHM) of the Si peak broadens. Note that since a peak shift due to charging occurs, it is necessary to correct using the C peak detected from surface contaminant hydrocarbons. In the present invention, the C peak detected from surface contaminant hydrocarbons was set to 284.6 eV. Also, in XPS, argon (Ar) ion sputter etching may be used for depth direction analysis, but since reduction, mixing, etc. due to the collision of argon (Ar) ions occur and there is a possibility of changing from the chemical bonding state in the original silicon oxide film, it is preferable to analyze the surface without using sputter etching. 2 In the case of the silicon oxide film mainly composed of SiO and including a plurality of other chemical bonding states, the peak top shifts to the range of 101 to 103.5 eV. Also, compared with the case of the SiO film, in the case of the silicon oxide film mainly composed of SiO and including a plurality of other chemical bonding states, the full width at half maximum (FWHM) of the Si peak broadens. Note that since a peak shift due to charging occurs, it is necessary to correct using the C peak detected from surface contaminant hydrocarbons. In the present invention, the C peak detected from surface contaminant hydrocarbons was set to 284.6 eV. Also, in XPS, argon (Ar) ion sputter etching may be used for depth direction analysis, but since reduction, mixing, etc. due to the collision of argon (Ar) ions occur and there is a possibility of changing from the chemical bonding state in the original silicon oxide film, it is preferable to analyze the surface without using sputter etching. 2 film, in the case of the silicon oxide film mainly composed of SiO and including a plurality of other chemical bonding states, the full width at half maximum (FWHM) of the Si peak broadens. Note that since a peak shift due to charging occurs, it is necessary to correct using the C peak detected from surface contaminant hydrocarbons. In the present invention, the C peak detected from surface contaminant hydrocarbons was set to 284.6 eV. Also, in XPS, argon (Ar) ion sputter etching may be used for depth direction analysis, but since reduction, mixing, etc. due to the collision of argon (Ar) ions occur and there is a possibility of changing from the chemical bonding state in the original silicon oxide film, it is preferable to analyze the surface without using sputter etching. 2 film, in the case of the silicon oxide film mainly composed of SiO and including a plurality of other chemical bonding states, the Si 2p peak's full width at half maximum (FWHM) broadens. Note that since a peak shift due to charging occurs, it is necessary to correct using the C 1s peak detected from surface contaminant hydrocarbons. In the present invention, the C 1s peak detected from surface contaminant hydrocarbons was set to 284.6 eV. Also, in XPS, argon (Ar) ion sputter etching may be used for depth direction analysis, but since reduction, mixing, etc. due to the collision of argon (Ar) ions occur and there is a possibility of changing from the chemical bonding state in the original silicon oxide film, it is preferable to analyze the surface without using sputter etching.

[0024] On the surface of the gas barrier layer 20 according to this embodiment, the ratio b / a of the Si 2p peak's full peak (a = Si 4+ , Si 3+ , Si 2+ , Si + , Si) to the Si 3+ , Si 2+ , Si + , Si peak (b = Si 3+ , Si 2+ , Si + , Si) measured by X-ray photoelectron spectroscopy (XPS) is preferably greater than 0.122. When the value of b / a is greater than 0.122, since it is a silicon oxide film containing many chemical bonding states other than SiO, it has a dense structure and can reduce the permeation path of gas molecules. 2 film, since it is a silicon oxide film containing many chemical bonding states other than SiO, it has a dense structure and can reduce the permeation path of gas molecules.

[0025] The gas barrier layer 20 according to this embodiment is preferably amorphous. Since the gas barrier layer 20 is an amorphous film, it becomes a film without grain boundaries that occur in the case of a polycrystalline film, so that the permeation path of gas molecules can be reduced. Whether the gas barrier layer 20 is amorphous or not can be evaluated by a known method. For example, it can be evaluated based on whether or not there are diffraction peaks of crystals in the X-ray diffraction pattern obtained by an analyzer such as an XRD (X-ray diffractometer).

[0026] The thickness of the gas barrier layer 20 varies depending on the configuration and film formation method used, but generally can be appropriately set within the range of 1 to 200 nm. If the thickness of the gas barrier layer 20 is less than 1 nm, a uniform film may not be obtained or the film thickness may not be sufficient, and the function as a gas barrier layer may not be fully exhibited. If the thickness of the gas barrier layer 20 exceeds 200 nm, there is a possibility of cracking due to external factors such as bending and stretching after film formation, resulting in loss of barrier properties. Preferably, it is within the range of 5 to 150 nm, and more preferably within the range of 10 to 120 nm.

[0027] FIG. 2 is a schematic diagram showing an example of a manufacturing apparatus for a gas barrier film according to an embodiment of the present invention. For manufacturing, a film forming apparatus 100 including a vacuum film forming chamber 40 and a winding and unwinding chamber 50 in which a winding roll 42 is arranged is used. The film forming chamber 40 and the winding and unwinding chamber 50 are partitioned by a partition wall and have independent exhaust systems. A gas adsorption device 48 is installed in the film forming chamber 40, and a gas adsorption device 49 having the same function as the gas adsorption device 48 is also installed near the winding roll 42 in the winding and unwinding chamber 50. The gas adsorption device 49 may be any device that condenses and adsorbs gas, and may be of the same type as or different from the gas adsorption device 48. Set the plastic film 41 to be the base material layer 10 on the unwinding roll 42. The plastic film 41 drawn out from the unwinding roll 42 passes through the film-forming roll 43 exposed in the film-forming chamber 40 and is then wound around the winding roll 44. In the film-forming chamber 40, a vapor deposition material 45 for forming the gas barrier layer 20 is set, and an electron beam gun 46 as a vapor deposition means is installed. The vapor deposition material 45 heated by the electron beam becomes vapor deposition particles 47 of vapor and is vapor-deposited on the plastic film. Thereby, the gas barrier layer 20 is formed on the plastic film 41.

[0028] In FIG. 2, as a method of heating the vapor deposition material 45, an electron beam vapor deposition method using the electron beam gun 46 is shown, but it may be heated using a resistance heating method or a high-frequency induction heating method, etc. to evaporate the vapor deposition material 45. Also, the resistance heating method may be a method of directly resistance-heating a crucible filled with the material, or there is no problem with another method.

[0029] The manufacturing apparatus for the gas barrier layer vapor-deposited film is not necessarily limited to this form, and if necessary, a plasma pretreatment apparatus may be installed in the unwinding / winding chamber, or a reaction gas introduction apparatus may be installed in the film-forming chamber. Regarding the arrangement of the rolls, there is no particular limitation either.

[0030] In this embodiment, the following changes are also possible. · Provide gas barrier layers on both sides of the base material layer 10. At this time, the two gas barrier layers may be the same or different. · Perform plasma treatment on the base material layer 10, and laminate the gas barrier layer 20 on the surface subjected to the plasma treatment to enhance the adhesion and gas barrier properties between the base material layer 10 and the gas barrier layer 20. As the plasma treatment on the base material layer 10, in addition to various known plasma treatments such as RIE (Reactive Ion Etching) treatment, corona treatment, hollow anode plasma treatment, and flat plate type plasma treatment, various known surface treatments such as ozone treatment and ion beam treatment can also be adopted as treatments having the same effects as the plasma treatment. As the gas species used for the plasma treatment, known discharge gases such as argon, oxygen, nitrogen, and helium can be used.

[0031] The second embodiment of the present invention will be described with reference to FIG. 3. In the following description, for the components that are the same as those already described, the same reference numerals will be given and the overlapping description will be omitted.

[0032] FIG. 3 is a schematic cross-sectional view of the gas barrier film 2 according to the present embodiment. The gas barrier film 2 further includes an overcoat layer 30 provided on the gas barrier layer 20.

[0033] The overcoat layer 30 is a layer containing an organic polymer resin, and has a function of protecting the gas barrier layer 20 and preventing the generation of cracks due to rubbing or bending.

[0034] Various known gas barrier films can also be used as the overcoat layer 30. In this case, the barrier property of the entire gas barrier film can be further improved. The overcoat layer 30 is obtained, for example, by forming a coating film made of a coating agent on the gas barrier layer 20 by a wet coating method and drying this coating film. In this specification, "coating film" means a wet film and "film" means a dry film, respectively.

[0035] The overcoat layer 30 may be a film containing at least one of a metal alkoxide and its hydrolyzate, or a reaction product thereof, and a water-soluble polymer (hereinafter sometimes referred to as an "organic-inorganic composite film"). Further, it preferably contains at least one of a silane coupling agent and its hydrolyzate.

[0036] Examples of the metal alkoxide and its hydrolyzate contained in the organic-inorganic composite film include those represented by the general formula M(OR)n such as tetraethoxysilane [Si(OC 2 H 5 ) 4 and triisopropoxyaluminum [Al(OC 3 H 7 ) 3 , and their hydrolyzates. One of these may be contained alone, or two or more thereof may be combined and contained.

[0037] The total content of at least one of the metal alkoxide and its hydrolyzate, or a reaction product thereof, in the organic-inorganic composite film can be, for example, 40 to 70% by mass. From the viewpoint of further improving the gas barrier property, the lower limit of the total content of at least one of the metal alkoxide and its hydrolyzate, or a reaction product thereof, in the organic-inorganic composite film can be 50% by mass. From the same viewpoint, the upper limit of the total content of at least one of the metal alkoxide and its hydrolyzate, or a reaction product thereof, in the organic-inorganic composite film can be 65% by mass.

[0038] The water-soluble polymer contained in the organic-inorganic composite film is not particularly limited, and examples thereof include polyvinyl alcohol-based polymers, acrylic polyol-based polymers, polysaccharides such as starch, methyl cellulose, and carboxymethyl cellulose. From the viewpoint of further improving the gas barrier property, it is preferable to contain a polyvinyl alcohol-based polymer. The number average molecular weight of the water-soluble polymer can be, for example, 40,000 to 180,000.

[0039] Polyvinyl alcohol-based water-soluble polymers can be obtained, for example, by saponifying (including partial saponification) polyvinyl acetate. This water-soluble polymer may have several tens of percent of acetate groups remaining, or may have only a few percent of acetate groups remaining.

[0040] In the organic-inorganic composite membrane, the content of the water-soluble polymer can be, for example, 15 to 50% by mass. When the content of the water-soluble polymer is 20 to 45% by mass, the gas barrier property of the organic-inorganic composite membrane can be further improved, which is preferable.

[0041] Examples of the silane coupling agent and its hydrolyzate contained in the organic-inorganic composite membrane include silane coupling agents having organic functional groups. Such silane coupling agents and their hydrolyzates include ethyltrimethoxysilane, vinyltrimethoxysilane, γ-chloropropylmethyldimethoxysilane, γ-chloropropyltrimethoxysilane, glycidoxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, and their hydrolyzates. One of these may be contained alone, or two or more of them may be combined.

[0042] It is preferable to use at least one of the silane coupling agent and its hydrolyzate having an epoxy group as an organic functional group. Examples of the silane coupling agent having an epoxy group include γ-glycidoxypropyltrimethoxysilane and β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane. The silane coupling agent having an epoxy group and its hydrolyzate may have an organic functional group different from the epoxy group, such as a vinyl group, an amino group, a methacryl group, or a ureyl group.

[0043] Silane coupling agents having organic functional groups and their hydrolyzates can further improve the gas barrier properties of the overcoat layer 30 and the adhesiveness to the gas barrier layer 20 through the interaction between the organic functional groups and the hydroxyl groups of the water-soluble polymer. In particular, the epoxy groups of the silane coupling agent and its hydrolyzate and the hydroxyl groups of polyvinyl alcohol can improve the adhesiveness between the overcoat layer 30 and the gas barrier layer 20 through interaction.

[0044] In the organic-inorganic composite film, the total content of at least one of the silane coupling agent, its hydrolyzate, or its reaction product can be, for example, 1 to 15% by mass. When the total content of at least one of the silane coupling agent, its hydrolyzate, or its reaction product is 2 to 12% by mass, the gas barrier properties of the organic-inorganic composite film can be further improved, which is preferable.

[0045] The thickness of the overcoat layer 30 can be set according to the required gas barrier properties and can be, for example, 0.05 to 5 μm. The thickness of the overcoat layer 30 is preferably 0.05 to 1 μm, and more preferably 0.1 to 0.5 μm. If the thickness of the overcoat layer 30 is 0.05 μm or more, sufficient oxygen barrier properties can be easily obtained. If the thickness of the overcoat layer 30 is 1 μm or less, it is easy to form a uniform coating surface, and the drying load and manufacturing cost can be suppressed.

[0046] The gas barrier film having the above-described organic-inorganic composite film as the overcoat layer 30 maintains excellent gas barrier properties even when subjected to boiling treatment or retort sterilization treatment.

[0047] In the gas barrier film according to each of the above-described embodiments, an undercoat layer 15 may be further provided between the base material layer 10 and the gas barrier layer 20, for example, as shown in the modified example of FIG. 4. That is, FIG. 4 shows a gas barrier film 2A of a modified example according to the second embodiment, but the same modification as in the first embodiment shown in FIG. 1 may be made. Further, a set of an undercoat layer 15 and a gas barrier layer 20 may be provided on both sides of the base material layer 10.

[0048] The undercoat layer 15 is provided on the base material layer 10 to enhance the adhesion between the base material layer 10 and the gas barrier layer 20, prevent the occurrence of peeling of the gas barrier layer 20, and further protect against mechanical damage such as scratches and abrasions. The material of the undercoat layer 15 is not particularly limited, and thermosetting resins, thermoplastic resins, ultraviolet curable resins, electron beam curable resins, etc. can be used.

[0049] Examples of the thermosetting resin for forming the undercoat layer 15 include thermosetting urethane resins composed of acrylic polyol resins and isocyanate prepolymers, phenol resins, urea melamine resins, epoxy resins, unsaturated polyester resins, silicone resins, etc. Among them, by using a composite of an acrylic polyol resin containing a hydroxy group and an isocyanate compound having at least two or more NCO groups in the molecule, the adhesion between the base material layer 10 and the gas barrier layer 20 can be enhanced.

[0050] The acrylic polyol resin is a polymer compound obtained by polymerizing (meth)acrylic acid derivative monomers, or a polymer compound obtained by copolymerizing (meth)acrylic acid derivative monomers and other monomers, etc., which has hydroxy groups at the terminal and side chains and reacts with the NCO groups of isocyanate compounds. The (meth)acrylic acid derivative monomers have hydroxy groups at the terminal and side chains. Examples of the (meth)acrylic acid derivative monomers include hydroxyethyl (meth)acrylate, hydroxybutyl (meth)acrylate, etc.

[0051] The above-mentioned other monomers are copolymerizable with (meth)acrylic acid derivative monomers having hydroxy groups at both the terminal and the side chain. Examples of the above-mentioned other monomers include (meth)acrylic acid derivative monomers having an alkyl group in the side chain such as methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, t-butyl (meth)acrylate, etc., (meth)acrylic acid derivative monomers having a carboxy group in the side chain such as (meth)acrylic acid, (meth)acrylic acid derivative monomers having an aromatic ring or a cyclic structure in the side chain such as benzyl (meth)acrylate, cyclohexyl (meth)acrylate, etc. Besides (meth)acrylic acid derivative monomers, styrene monomers, cyclohexyl maleimide monomers, phenyl maleimide monomers, etc. are conceivable. The above-mentioned other monomers may themselves have hydroxy groups at both the terminal and the side chain.

[0052] The acrylic polyol resin is preferably a polymer compound obtained by polymerizing a (meth)acrylic acid derivative monomer having a carboxy group in the side chain such as (meth)acrylic acid. When forming the undercoat layer 15, by forming it using a composite of an acrylic polyol resin obtained by polymerizing a monomer having a carboxy group and an isocyanate-based compound, a gas barrier laminated film having a higher water vapor barrier property can be obtained.

[0053] Regarding the acrylic polyol resin containing a hydroxy group that can be used for the undercoat layer 15, although it is not particularly limited, it is desirable that the hydroxy value is 50 mgKOH / g or more and 250 mgKOH / g or less. Here, the hydroxy value (mgKOH / g) is an index of the amount of hydroxy groups in the acrylic polyol resin, and indicates the number of mg of potassium hydroxide required to acetylate the hydroxy groups in 1 g of the acrylic polyol resin. Also, the weight average molecular weight of the acrylic polyol resin is not particularly limited, but specifically, it is preferably 3000 or more and 200000 or less. In particular, it is preferably 5000 or more and 100000 or less. Further, it is more preferably 5000 or more and 40000 or less.

[0054] As the isocyanate compound, those having two or more NCO groups in the molecule are used. Examples of monomeric isocyanates include aromatic isocyanates such as tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), xylene diisocyanate (XDI), tetramethylxylylene diisocyanate (TMXDI), aliphatic isocyanates such as hexamethylene diisocyanate (HDI), bis(isocyanatomethyl)cyclohexane (H6XDI), isophorone diisocyanate (IPDI), dicyclohexylmethane diisocyanate (H12MDI), etc. Further, polymers or derivatives of these monomeric isocyanates can also be used. For example, there are trimeric nurate type, adduct type reacted with 1,1,1-trimethylolpropane, etc., biuret type reacted with biuret, etc.

[0055] The isocyanate compound can be arbitrarily selected from the above-mentioned isocyanate compounds or their polymers and derivatives, and can be used alone or in combination of two or more.

[0056] As an example of the undercoat layer 15, a solution composed of a composite of the above acrylic polyol resin and the above isocyanate compound and a solvent is applied onto the base material layer 10 and reaction-cured to form it. The equivalent ratio (NCO / OH) of the NCO group of the isocyanate compound to the hydroxy group of the acrylic polyol resin is preferably 0.3 or more and 2.5 or less. The solvent used here may be any solvent that dissolves the above acrylic polyol resin and isocyanate compound. Examples of the solvent include methyl acetate, ethyl acetate, butyl acetate, cyclohexanone, acetone, methyl ethyl ketone, dioxolane, tetrahydrofuran, etc. In practice, these solvents can be used alone or in combination of two or more.

[0057] As the thermoplastic resin for forming the undercoat layer 15, for example, polyols having two or more hydroxy groups such as acrylic polyol, polyester polyol, polycarbonate polyol, polyether polyol, polycaprolactone polyol, epoxy polyol, etc., polyvinyl resins such as polyvinyl acetate and polyvinyl chloride, polyvinylidene chloride resin, polystyrene resin, polyethylene resin, polypropylene resin, polyurethane resin, etc. are appropriately selected. Further, these may be mixed at any ratio. The hydroxy value of the polyol is not particularly limited, but it is preferably 10 mgKOH / g or more and 250 mgKOH / g or less.

[0058] As the ultraviolet curable resin or electron beam curable resin for forming the undercoat layer 15, although not particularly limited as the organic polymer resin, it is desirable to contain at least a resin having a hydroxy value in the range of 10 or more and 100 mgKOH / g or less. Also, although not particularly limited as the organic polymer resin, it is desirable to contain at least a resin having an acid value in the range of 10 or more and 100 mgKOH / g or less. Here, the acid value (mgKOH / g) indicates the number of mg of potassium hydroxide required to neutralize free fatty acids, resin acids, etc. contained in 1 g of the sample. Also, it is desirable to contain at least a thermoplastic resin as the organic polymer resin. When the hydroxy value or acid value is less than 10 mgKOH / g, the chemical bonding force between the functional group and the surface of the gas barrier layer 20 becomes weak, and the adhesion to the gas barrier layer 20 tends to be low. When the hydroxy value or acid value exceeds 100 mgKOH / g, deposits containing hydroxy groups generated by the decomposition of the undercoat layer 15 in durability tests such as the damp heat test tend to inhibit the adhesion between the undercoat layer 15 and the gas barrier layer 20.

[0059] Examples of monomers that can be used in the ultraviolet curable resin or electron beam curable resin for forming the undercoat layer 15 include monofunctional monomers such as ethyl (meth)acrylate, ethylhexyl (meth)acrylate, styrene, methylstyrene, N-vinylpyrrolidone, etc., and polyfunctional monomers such as trimethylolpropane (meth)acrylate, hexanediol (meth)acrylate, tripropylene glycol di(meth)acrylate, diethylene glycol (meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol (meth)acrylate, etc. Examples of oligomers that can be used in this ultraviolet curable resin or electron beam curable resin include urethane acrylate, epoxy acrylate, polyester acrylate, etc.

[0060] When two or more kinds selected from thermosetting resins, thermoplastic resins, ultraviolet curable resins, and electron beam curable resins are used in combination as the organic polymer resin for forming the undercoat layer 15, the blending ratio is not particularly limited.

[0061] The undercoat layer 15 may further contain additives as required in addition to the organic polymer resin. Examples of additives include antioxidants, weathering agents, heat stabilizers, lubricants, crystal nucleating agents, ultraviolet absorbers, plasticizers, antistatic agents, colorants, fillers, surfactants, silane coupling agents, etc.

[0062] The film thickness of the undercoat layer 15 is preferably 0.05 μm or more and 10.0 μm or less. In particular, it is preferably 0.05 μm or more and 5.0 μm or less. If it is thinner than 0.05 μm, the adhesion between the base material layer 10 and the gas barrier layer 20 will be insufficient. If it is thicker than 10.0 μm, the influence of internal stress will increase, the gas barrier layer 20 cannot be laminated neatly, the manifestation of barrier properties will be insufficient, and furthermore, transparency and coating accuracy will also be insufficient.

[0063] As a method for forming the undercoat layer 15, a normal coating method can be used. For example, well-known methods such as dipping method, roll coating, gravure coating, reverse coating, air knife coating, comma coating, die coating, screen printing method, spray coating, gravure offset method, organic vapor deposition method, etc. can be used. As the drying method, a method of applying heat such as hot air drying, hot roll drying, high-frequency irradiation, infrared irradiation, UV irradiation, electron beam irradiation, etc. can be used alone or in combination of two or more kinds. Further, a film previously coated on another resin substrate by the above forming method may be transferred to the substrate layer 10 by a transfer method such as adhesive transfer, heat transfer, UV transfer, etc.

[0064] The gas barrier film according to each embodiment of the present invention will be further described using examples and comparative examples. The technical scope of the present invention is not limited based only on the specific contents of the examples and comparative examples.

[0065] (Example 1) As the base material layer, a biaxially stretched polypropylene film with a thickness of 20 μm was used. By using both the Meissner coils (cooling temperature: both -120 °C) installed near the unwind roll in the film forming chamber and the unwind / rewind chamber, the partial pressure of m / z 18 in the film forming chamber measured by the partial pressure gauge during film formation was adjusted to 0.02 Pa. In the film forming chamber, a SiOx vapor deposition material with an appropriately adjusted ratio of Si material and SiO 2 material was sublimated, and a gas barrier layer (film thickness 40 nm, O / Si 1.7) made of silicon oxide (SiOx) was formed on the base material layer by electron beam evaporation method. Thus, the gas barrier film according to Example 1 was produced.

[0066] (Example 2) Except that the partial pressure of m / z 18 was adjusted to 0.01 Pa and the O / Si of the gas barrier layer was set to 1.3 by appropriately adjusting the ratio of the Si material and SiO 2 material, the gas barrier film according to Example 2 was produced in the same procedure as Example 1.

[0067] (Example 3) The partial pressure of m / z 18 was adjusted to 0.04 Pa, and the gas barrier film according to Example 3 was produced in the same procedure as Example 1, except that the ratio of the Si material and the SiO 2 material was appropriately adjusted so that O / Si of the gas barrier layer was 1.8.

[0068] (Example 4) The gas barrier film according to Example 4 was produced in the same procedure as Example 1, except that the partial pressure of m / z 18 was adjusted to 0.01 Pa.

[0069] (Example 5) The gas barrier film according to Example 5 was produced in the same procedure as Example 1, except that the partial pressure of m / z 18 was adjusted to 0.04 Pa.

[0070] (Example 6) The gas barrier film according to Example 6 was produced in the same procedure as Example 1, except that the film thickness of the gas barrier layer was adjusted to 10 nm. (Example 7) The gas barrier film according to Example 7 was produced in the same procedure as Example 1, except that the film thickness of the gas barrier layer was adjusted to 120 nm.

[0071] (Example 8) A coating agent obtained by mixing the following liquid (1) and liquid (2) at a weight ratio of 6:4 was applied by a gravure coating method onto the gas barrier layer of the gas barrier film according to Example 1, and dried to form an overcoat layer with a thickness of 0.4 μm. (1) Liquid: 89.6 g of hydrochloric acid (0.1 N) was added to 10.4 g of tetraethoxysilane, stirred for 30 minutes and hydrolyzed to obtain a hydrolysis solution with a solid content of 3 wt% (in terms of SiO 2 conversion) (2) Liquid: A 3 wt% aqueous / isopropyl alcohol solution of polyvinyl alcohol (weight ratio of water:isopropyl alcohol 90:10) Thus, the gas barrier film according to Example 8 was produced.

[0072] (Example 9) On the gas barrier layer of the gas barrier film according to Example 1, an aqueous solution of polyvinyl alcohol, a hydrolyzed solution of tetraethoxysilane, and a hydrolyzed solution of 1,3,5-tris(3-trimethoxysilylpropyl)isocyanurate silane coupling agent were mixed so that the solid content weight ratio after drying was 30:60:10, and a coating agent with a solid content of 5 wt% was applied by the gravure coating method, dried, and an overcoat layer with a thickness of 0.4 μm was formed. Thus, the gas barrier film according to Example 9 was produced.

[0073] (Example 10) On the base material layer, a mixed solution of acrylic polyol and isocyanate was applied by the gravure coating method and dried to form an undercoat layer with a thickness of 0.2 μm. On the undercoat layer, a gas barrier layer 20 was formed in the same procedure as in Example 1, and the gas barrier film according to Example 10 was produced.

[0074] (Comparative Example 1) Neither of the Meissner coils installed in the film formation chamber and the unwind / rewind chamber was used, and the partial pressure of m / z18 in the film formation chamber measured by a manometer during film formation was set to 0.10 Pa. Also, except for adjusting the ratio of the Si material and the SiO 2 material appropriately so that the O / Si of the gas barrier layer was 1.9, the gas barrier film according to Comparative Example 1 was produced in the same procedure as in Example 1.

[0075] (Comparative Example 2) Except for adjusting the partial pressure of m / z18 to 0.04 Pa and using only the SiO 2 material as the SiOx material without mixing the Si material, the gas barrier film 1 according to Comparative Example 2 was produced in the same procedure as in Example 1. The O / Si of the gas barrier layer in Comparative Example 2 was 2.0.

[0076] (Comparative Example 3) A gas barrier film according to Comparative Example 3 was produced in the same procedure as in Example 1, except that neither the Meissner coil installed in the film forming chamber nor the Meissner coil installed in the unwind / rewind chamber was used, and the partial pressure of m / z 18 in the film forming chamber measured with a manometer during film formation was set to 0.10 Pa.

[0077] (Comparative Example 4) A gas barrier film according to Comparative Example 4 was produced in the same procedure as in Example 1, except that only the Meissner coil installed in the film forming chamber was used, and the partial pressure of m / z 18 in the film forming chamber measured with a manometer during film formation was set to 0.07 Pa.

[0078] The following evaluations were performed on the laminates according to the examples and comparative examples. The evaluation was performed on 3 samples for each example. (FT-IR analysis) The FT-IR analysis was performed under the following measurement conditions using a Fourier transform infrared spectrophotometer (FT / IR-4600) manufactured by JASCO Corporation. · Measurement method: Reflection ATR method (measurement from the gas barrier layer side of the barrier film) · Measurement atmosphere: Air · Measurement temperature: Room temperature · ATR crystal: Germanium (wavenumber range 600 - 5500 cm -1 ) · Resolution: 4.0 cm -1 · Number of accumulations: 64 times In the infrared absorption spectrum obtained by FT-IR analysis, using the software attached to the apparatus, the peak area derived from the Si-O-Si bond (720 - 1320 cm -1 ) and the peak area derived from the Si-OH bond (830 - 910 cm -1 ) were each plotted at both ends of the defined range, a baseline was drawn connecting the plots, and the area of the portion enclosed by the spectrum and the baseline was calculated. Note that the region below the baseline was ignored and not included in the area. Although the FT-IR analysis was measured by the ATR method, the area ratios shown below are based on the data before correction without performing corrections such as ATR correction and baseline correction.

[0079] (XPS Analysis of Gas Barrier Layer) Regarding the composition ratio and bonding state of the inorganic oxide film, which is the gas barrier layer, measurements were carried out using an X-ray photoelectron spectrometer (JPS■9010MX) manufactured by JEOL Ltd. The X-ray source used was MgKα, and the pass energy was set to 5 eV. For Si 2p narrow spectrum, it was measured in the range of 95 - 106 eV, for O 1s narrow spectrum, it was measured in the range of 525 - 538 eV, and for C 1s narrow spectrum, it was measured in the range of 278 - 290 eV, respectively. Also, to avoid the influence of noise, each narrow spectrum was subjected to more than 30 repeated scans and integrations. At that time, in order to avoid changes in the chemical bonding state in the silicon oxide film due to reduction or mixing caused by the collision of argon (Ar) ions, the outermost surface composition was measured without performing argon etching. Also, since peak shift due to charging occurred, correction was performed so that the C 1s peak detected from surface contaminating hydrocarbons became 284.6 eV.

[0080] (Water Vapor Barrier Performance Evaluation) Regarding the gas barrier films according to each example, the water vapor transmission rate (WVTR) was evaluated using a water vapor transmission rate measuring device (product name: PERMATRAN3 / 34G, measurement conditions: 40°C - 90%RH, unit: g / (m 2 ·day)) manufactured by Mocon. The results are shown in Table 1.

[0081]

Table 1

[0082] For the gas barrier films according to the examples, the ratio of the peak area of the absorption peak at 830 cm -1 or higher and 1320 cm -1 or lower, which is derived from the Si-O-Si bond calculated by FT-IR of the inorganic oxide film layer 13, to the peak area of the absorption peak at 910 cm -1 or higher and 910 cm -1 or lower, which is derived from the Si-OH bond, was 0.025 or less. The variation in WVTR of the examples was within ±0.5 g and was stable. In Examples 8 and 9 having an overcoat layer, the water vapor barrier property was improved as compared with Examples 1 to 5.

[0083] On the other hand, in many of the gas barrier films according to the comparative examples, the ratio of the peak area of the absorption peak at 830 cm -1 or higher and 1320 cm -1 or lower derived from the Si-OH bond to the peak area of the absorption peak at 720 cm -1 or higher and 910 cm -1 or lower derived from the Si-O-Si bond calculated by FT-IR of the inorganic oxide film layer 13 exceeded 0.025. The WVTR of the comparative examples exceeded 1.0 g(m 2 ·day) except for one sample. Also, the variations in WVTR all exceeded ±0.5 g (exceeded the standard deviation of 0.5 g), and the quality was not stable. For Lot 3 of Comparative Example 4 where the WVTR was less than 1.0 g(m 2 ·day), the ratio of the peak area of the absorption peak at 830 cm -1 or higher and 910 cm -1 or lower derived from the Si-OH bond to the peak area of the absorption peak at 720 cm -1 or higher and 1320 cm -1 or lower derived from the Si-O-Si bond calculated by FT-IR of the inorganic oxide film layer 13 was 0.025 or less, and it was confirmed that it had performance corresponding to that of the examples. From this, it was shown that this parameter is useful for evaluating the performance of the transparent inorganic oxide film and that information that cannot be obtained by looking only at O / Si can be obtained.

[0084] Furthermore, from the results of the examples and comparative examples, it was shown that the gas barrier film according to the present embodiment can be stably manufactured by forming a gas barrier layer on a substrate layer passing through a film formation chamber using a vapor deposition material in which an Si material and an SiO 2 material are mixed with the partial pressure value of m / z18 in the film formation chamber being 0.05 Pa or less using a gas adsorption device.

[0085] As described above, each embodiment and example of the present invention have been explained. However, the specific configuration is not limited to this embodiment, and it also includes configuration changes, combinations, etc. within the scope not departing from the gist of the present invention.

Explanation of Reference Numerals

[0086] 1, 2, 2A Gas barrier film 10 Substrate layer 15 Undercoat layer 20 Gas barrier layer 30 Overcoat layer 40 Film forming chamber 41 Plastic film 42 Unwinding roll 43 Film forming roll 44 Winding roll 45 Evaporation material 46 Electron beam gun 47 Evaporated particles 48, 49 Gas adsorption device 50 Unwinding and winding chamber 100 Film forming apparatus

Claims

1. A base material layer, A gas barrier layer formed on the base material layer and containing silicon oxide, Comprising, The gas barrier layer has, in the infrared absorption spectrum from the surface side, a ratio of the peak area of the absorption peak at 830 cm －１ or higher to 1320 cm －１ or lower, which is derived from the Si—O—Si bond, to the peak area of the absorption peak at 910 cm －１ or higher to 830 cm －１ or lower, which is derived from the Si—OH bond, of 0.025 or less. A gas barrier film.

2. On the surface of the gas barrier layer, the total peak of the Si2p peak measured by X-ray photoelectron spectroscopy (XPS) (a = Si ４＋ Si ３＋ Si ２＋ Si ＋ Si), the ratio b / a of the peak of Si ３＋ Si ２＋ Si ＋ Si (b = Si ３＋ Si ２＋ Si ＋ Si) is greater than 0.122, The gas barrier film according to Claim 1.

3. The thickness of the gas barrier layer is 1 nm or more and 200 nm or less, The gas barrier film according to Claim 1.

4. Further comprising an overcoat layer formed on the gas barrier layer, The gas barrier film according to Claim 1.

5. The overcoat layer contains at least one of a metal alkoxide, a hydrolyzate of a metal alkoxide, a reaction product of a metal alkoxide, and a reaction product of a hydrolyzate of a metal alkoxide, and a water-soluble polymer, The gas barrier film according to Claim 4.

6. The overcoat layer contains at least one of a silane coupling agent, a hydrolyzate of a silane coupling agent, a reaction product of a silane coupling agent, and a reaction product of a hydrolyzate of a silane coupling agent, The gas barrier film according to Claim 4.

7. Further comprising an undercoat layer provided between the base material layer and the gas barrier layer, The undercoat layer contains at least one of a thermosetting resin, a thermoplastic resin, an ultraviolet curable resin, and an electron beam curable resin, The gas barrier film according to Claim 1.

8. Further comprising an undercoat layer provided between the base material layer and the gas barrier layer, The undercoat layer is composed of a cured product of a composition containing an acrylic polyol resin and an isocyanate compound, The gas barrier film according to Claim 1.

Images