JP2001071425A - Gas barrier film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gas barrier film excellent in transparency and flexibility and optimum as a packaging material not using a substance causing the disruption of environment. SOLUTION: A gas barrier film is obtained by laminating a gas barrier film based on alkali metal polysilicate represented by M2O.nSiO2 (wherein M is lithium or a plurality of alkali metals containing lithium and n is a molar ratio of 1-20) and a water soluble polymer or/and a nitrogen compd. on the single surface or both surfaces of a base material comprising a plastic material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a packaging film used in the field of packaging non-foodstuffs such as foodstuffs, pharmaceuticals, and electronic components, and more particularly to a film by suppressing permeation of gases such as oxygen and water vapor. The present invention relates to a gas barrier film that suppresses oxidation, decomposition, and alteration of a gas.

[0002]

2. Description of the Related Art In recent years, packaging materials used for packaging foods, non-foods, and the like are required to suppress deterioration of contents and maintain their functions and properties. It is necessary to prevent the influence of the gas that alters the substance, and it is required to have a gas barrier function of blocking such gas (gas).

[0003] Conventionally, as a gas barrier layer, a metal foil or a metal-deposited film made of a metal such as aluminum,
Resin films such as polyvinyl alcohol, ethylene-vinyl alcohol copolymer, polyvinylidene chloride, and polyacrylonitrile, or films coated with these resins, and ceramic vapor-deposited films on which inorganic oxides such as silicon oxide and aluminum oxide are further deposited. Mainly used.

[0004]

However, metal foils and vapor-deposited films are excellent in gas barrier properties, but the contents cannot be confirmed by seeing through the packaging material, the metal detector cannot be used in the inspection, and the disposal after use. In such a case, there is a problem that it must be treated as an incombustible substance. In addition, gas barrier resin films and films coated with them are highly temperature and humidity dependent and cannot maintain a high level of gas barrier properties.Polyvinylidene chloride and polyacrylonitrile can be used as raw materials for harmful substances during disposal and incineration. There are problems such as. Further, the ceramic vapor-deposited film and the like have problems such that the vapor-deposited layer lacks flexibility due to ceramics, and that sufficient attention must be paid to processing suitability.

As a technique for solving such a problem, there is the following proposal as a gas barrier material provided with flexibility by a wet coating which can be manufactured at low cost. 1. A gas barrier material having a film of a water-soluble dispersion of lithium silicate provided on the surface of a polymer molded product (Japanese Patent Laid-Open No. 49-51)
No. 366). 2. A gas barrier material in which a coating of a dispersion solution of silica and polyvinyl alcohol is provided on a polyester substrate (Japanese Patent Publication No. 63-25615). 3. A gas barrier material for coating an aqueous liquid containing an alkali metal silicate and a silane coupling agent on the surface of a polymer molded product (JP-A-8-238711). 4. A gas barrier material having a composite of a metal alkoxide or a hydrolyzate thereof and a water-soluble resin on a plastic substrate (JP-A-6-192454, etc.).

[0006] The above-mentioned gas barrier material is about 1.6 / 1.
It has been confirmed that a gas barrier property and a water vapor barrier property can be imparted by providing a lithium silicate inorganic coating having a molar ratio of SiO ₂ to LiO ₂ of about 4.6 / 1. It has been known for some time that lithium polysilicate is useful as a gas barrier material, particularly as a material for improving oxygen barrier properties. However, when a film is formed on a plastic film using lithium polysilicate alone, Li ₂ O · n
The film cannot be formed unless the molar ratio represented by SiO ₂ is within the range of n ≦ 5, and the lithium polysilicate film formed in the range of n ≦ 5 also undergoes rapid shrinkage due to drying during film formation and film formation. Since the material itself lacks flexibility, it cannot follow a flexible plastic substrate unless it is dried slowly at a low temperature for a long period of time, causing damages such as cracks and reducing oxygen barrier properties.

The gas barrier material of the above 2 is M ₂ O · n
Particle size 5 where n of SiO ₂ (M is an alkali metal) is 50 or more
Using a silica sol having a thickness of 0 nm or less at a weight ratio of 40 to 90%, the insolubility of the coating film in hot water has been confirmed.

[0008] The gas barrier material of the above 3 is M ₂ O · n
A silane coupling agent is mixed with an alkali metal silicate (water glass) having n of 2 or more in SiO ₂ (M is an alkali metal) to obtain a polymer molded product having a wetting tension of 50 dyne / cm or more. It is described that when formed by coating, high adhesion and oxygen barrier properties can be obtained. However, in this invention, it is described that the composition of potassium silicate and the silane coupling agent can provide the highest oxygen barrier properties, but does not mention the water vapor barrier properties.

[0009] The gas barrier material of the above 4 is a metal alkoxide of Si or Al or its hydrolysis.
5 to 80% by weight of water-soluble resin (polyvinyl alcohol)
A very high gas barrier can be achieved with the included complex. However, since the gas barrier function affects the reaction of hydrolysis of the metal alkoxide, the hydrolysis reaction must be strictly controlled. Further, similarly to the above 3, there is no mention of the water vapor barrier property.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art, and is excellent in transparency so that the contents can be seen through, a metal detector can be used, and a wet coating system using existing equipment can be used. And short time and 100 ℃
A gas barrier property can be exhibited in the following drying process at a low temperature. In addition, it has processing aptitude, high oxygen barrier property and water vapor barrier property under high temperature and high humidity, and also improves flexibility, which is a drawback of inorganic oxide materials required for packaging materials, and causes environmental damage. An object of the present invention is to provide a gas barrier film that is optimal as a packaging material without using any of the above.

In particular, the present invention provides a high water vapor barrier property which cannot be obtained by a ceramic skeleton gas barrier material using a sol-gel method which has been proposed many times before.
It is an extremely effective gas barrier film for moisture-proof packaging, which is an important factor for the stable protection of contents, which is a basic function of the package, such as long-term storage of foods that easily absorb moisture and prevention of evaporation of high moisture contents.

[0012]

Means for Solving the Problems The present invention has been made to achieve the above-mentioned object, and the invention of claim 1 is to provide a substrate made of a plastic material on one or both surfaces of M ₂ O · nS.
an alkali metal polysilicate represented by iO ₂ (M is lithium or a plurality of alkali metals containing lithium, n is in the range of 1 to 20) and a gas barrier coating mainly composed of a water-soluble polymer. It is a gas barrier film characterized by being laminated.

According to a second aspect of the present invention, a plastic material is used.
On one or both sides of the base material ₂On SiOn
₂(M is lithium or a plurality of alkalis containing lithium
Metal, n is a molar ratio in the range of 1 to 20)
Mainly composed of potassium metal polysilicate and nitrogen compound
Gas barrier characterized by laminating a gas barrier coating
A film.

According to a third aspect of the present invention, a plastic material is used.
On one or both sides of the base material ₂On SiOn
₂(M is lithium or a plurality of alkalis containing lithium
Metal, n is a molar ratio in the range of 1 to 20)
Potassium metal polysilicate, water-soluble polymer and nitrogenation
Laminating a gas barrier coating with a compound as the main component
It is a characteristic gas barrier film.

According to a fourth aspect of the present invention, based on the first or third aspect, the water-soluble polymer is at least one selected from saccharides, polyvinyl alcohol, polyethyleneimine and derivatives thereof. It is a gas barrier film characterized by the above.

The invention according to claim 5 is the invention according to claim 1, claim 3,
Alternatively, based on the invention according to claim 4, the weight ratio of SiO ₂ (silica component) / water-soluble polymer in the gas barrier coating is in the range of 50/50 to 99.9 / 0.01. It is a gas barrier film characterized by the above.

According to a sixth aspect of the present invention, there is provided a gas barrier film according to the second or third aspect, wherein the nitrogen compound is an amine containing an amino group-containing silane coupling agent. is there.

According to a seventh aspect of the present invention, based on any one of the first to sixth aspects, an anchor coat layer is provided between the substrate made of the plastic material and the gas barrier coating. It is a gas barrier film characterized by the above.

An eighth aspect of the present invention is the gas barrier film according to the seventh aspect, wherein the anchor coat layer contains an acrylic resin and an isocyanate compound as main components.

According to a ninth aspect of the present invention, there is provided a gas barrier film according to any one of the first to eighth aspects, wherein the substrate made of the plastic material is a polyolefin.

According to a tenth aspect of the present invention, there is provided a gas barrier film according to the ninth aspect, wherein the substrate made of the polyolefin imparts moisture-proof properties.

An eleventh aspect of the present invention is based on the ninth or tenth aspect, wherein the base material made of polyolefin is a biaxially stretched film having two or more layers by coextrusion. Gas barrier film.

[0023]

According to the present invention, in a configuration in which a gas barrier coating is laminated on a substrate made of a plastic material, the gas barrier coating is formed of M ₂ O · nSiO ₂ (M is lithium or a plurality of alkali metals containing lithium, n is a molar ratio in the range of 1 to 20), and contains an alkali metal polysilicate as a main component.

According to the first aspect of the present invention, when a water-soluble polymer is added to an alkali metal polysilicate and the main component thereof is lithium silicate, it has a very dense bond when dried at a low temperature, Since the conductive polymer imparts film formability and flexibility, a gas barrier laminate having high oxygen barrier properties with little dependence on temperature and humidity can be obtained.

According to the second aspect of the present invention, when a nitrogen compound is added to an alkali metal polysilicate as a main component, the gas barrier film is a silicon oxide film containing lithium, nitrogen and carbon as essential components. It has a very dense bond even at low temperature drying to the extent that the plastic material is not damaged. Therefore, it is possible to obtain a gas barrier laminate having an oxygen barrier property with little dependence on temperature and humidity and a high water vapor barrier property under a high temperature and high humidity environment.

Further, according to the third aspect of the present invention, when a nitrogen compound and a water-soluble polymer are added to the alkali metal polysilicate and the main components thereof are used, lithium, nitrogen and carbon are made essential components by drying at a low temperature. The silicon oxide film has a very dense bond, and the water-soluble polymer gives film formability and flexibility, so it has very little temperature / humidity dependence and very high oxygen barrier properties in high temperature and high humidity environments And a gas barrier laminate having a water vapor barrier property can be obtained.

In the present invention, a high barrier property can be obtained by drying at a low temperature, so that an excellent barrier film having very little temperature and humidity dependence can be obtained from a polyolefin film or the like lacking in heat resistance.

Since the above gas barrier material can be applied by wet coating, an existing gravure printing machine or the like can be used, and production is easy and low cost processing is possible. Further, by using a highly moisture-proof layer such as a cyclic olefin copolymer or a polyolefin film having a multilayer structure by co-extrusion such as a heat seal layer as a base material, more high functions can be obtained.

[0029]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention relates to a method of forming a substrate comprising a plastic material or a plastic material subjected to a surface modification treatment on one or both surfaces thereof by using M ₂ O · nSiO ₂ (where M is lithium or a plurality of Alkali metal, n is a molar ratio in the range of 1 to 20), and a gas barrier coating mainly composed of a water-soluble polymer and / or a nitrogen compound. It is a gas barrier film.

The above-mentioned plastic materials include, for example, polyester films such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN); polyolefin films such as polyethylene and polypropylene; polystyrene films; polyamide films such as 6-nylon; An engineering plastic film such as a polyimide film is used, and a composite multilayer film formed by co-extrusion of these materials is also included. Since the gas barrier composite coating of the present invention can be dried at a low temperature, it can be applied regardless of stretching or unstretching, but stable coating properties, film strength, dimensional stability, printability, price, disposal In consideration of the properties, transparency, hygiene and the like, a biaxially stretched single-layer film or a co-extruded composite multilayer film mainly composed of polypropylene, polyamide or polyester is preferred. In consideration of transparency, price, film strength, printability, moisture resistance, etc., biaxially stretched polyolefin films represented by polyethylene and polypropylene are more preferable.

Further, the above-mentioned polyolefin film includes a biaxially stretched film in which two or more layers are simultaneously formed by coextrusion, and is a cyclic film obtained by copolymerizing ethylene with dicyclopentadiene, norbornene, cyclohexene or the like. A highly moisture-proof layer mainly composed of an olefin copolymer, a highly moisture-proof polypropylene film laminated on one or both sides with a polypropylene layer, etc. for printability, price, oil resistance, adhesion, etc. By using a heat-sealable polypropylene film or the like as the base material, it is possible to simplify the use of contents that require an even higher moisture-proof property while providing an oxygen barrier property and the laminating step of the sealant film.

As the components of the base material, various well-known additives and additives such as suitability as a packaging material such as suitability for printing, suitability for post-processing, suitability for filling and packaging, suitability for contents resistance, and suitability for film formation are given. Stabilizers such as antistatic agents, plasticizers, lubricants, antioxidants and the like may be added.

The surface modification treatment mentioned above is intended to enhance the gas barrier function by facilitating the adhesion and formation of the gas barrier coating, and to improve the gas barrier function on one or both surfaces of the substrate surface, a corona discharge treatment and a low-temperature plasma treatment. Improve the polarity of the outermost surface of the substrate by a DRY process such as frame treatment, or use a wet coating WET process to produce polyethyleneimine or its derivatives, silane coupling agents, organic titanates, polyacrylic, polyester, polyurethane, epoxy System, isocyanate system,
Polyamide-based resin and polyolefin-based emulsion,
This is to provide an anchor coat layer containing a surfactant or the like. In addition, it is more preferable that the surface modification treatment is performed in-line immediately before the formation of the gas barrier coating, because the surface modification state may change with time.

Although the thickness of the base material is not particularly limited, it is practically in the range of 3 to 200 μm in consideration of suitability as a packaging material and the case of laminating another resin layer. It is more preferable that the thickness is in the range of 3 to 30 μm depending on the application.

Next, the gas barrier coating layer of the present invention will be described. The purpose of this layer is to provide a high degree of gas barrier properties, which has very little dependence on temperature and humidity and suppresses a decrease in barrier under long-term moisture absorption conditions. In order to achieve the above object, the gas barrier film is M ₂ O · nSiO.
₂ (M is lithium or a plurality of alkali metals containing lithium, n is a molar ratio in the range of 1 to 20), and needs to be a coating mainly composed of an alkali metal polysilicate.

Lithium silicate, which is an essential component of the above alkali metal polysilicate having gas barrier properties, is represented by Li ₂ O · nSiO ₂ (n is a molar ratio), and its solution is generally called water glass using water as a solvent. It is an alkali silicate aqueous solution. An alkali metal other than lithium refers to all elements belonging to Group 1A, but industrially relatively inexpensive sodium and potassium are generally used in many cases. However, a dry coating of an aqueous alkali silicate solution containing one or more alkali metals containing no lithium cannot provide high oxygen barrier properties with little dependence on temperature and humidity and high water vapor barrier properties under high temperature and high humidity.

First, by blending a water-soluble polymer having compatibility with an aqueous solution of lithium silicate and a flexible organic component as a skeleton, the molar ratio represented by Li ₂ O · nSiO ₂ is 1
It is possible to form a wide range of lithium polysilicate coatings ranging from 20 to 20. Even when applied on a plastic substrate as a gas barrier material, it is possible to form a flexible coating that suppresses shrinkage and does not cause cracks.

The above-mentioned water-soluble polymer is a polymer having a hydroxyl group, a carboxyl group or an amino group, and needs to be water-soluble in view of compatibility with an aqueous solution of an alkali silicate. For example, polyvinyl alcohol or a derivative thereof, polyethyleneimine or a derivative thereof, ethylene-
Vinyl alcohol copolymers, sugars such as starches and celluloses, polyacrylic acid and polymethacrylic acid or copolymers thereof, and polyethyleneimines can be used. Further, in consideration of compatibility with an aqueous alkali silicate solution and gas barrier properties, it is preferable to have weakly acidic to weakly alkaline properties, and it is more preferable to use saccharides, polyvinyl alcohol, polyethyleneimine or derivatives thereof.

The above saccharides refer to organic compounds containing glucose as a main component, and include oligosaccharides, oligosaccharides, and polysaccharides. The saccharides used in the present invention are more preferably starches and celluloses belonging to polysaccharides in which glucose is polymerized in consideration of the film-forming properties and flexibility of the gas barrier coating.

The polyvinyl alcohol is a polymer obtained by polymerizing and saponifying vinyl acetate as a main raw material. The polyvinyl alcohol used in the present invention includes film-forming properties of a gas barrier coating, flexibility, Considering solubility and water resistance, the polymerization degree is 300 to 3000, and the saponification degree is 95.
More than mol% is more preferable. In addition, the polyvinyl alcohol derivative includes a modified polyvinyl alcohol into which a silanol group, a carboxyl group, an amino group, a sulfonic acid group, an acetoacetyl group, or the like is introduced in an amount of 10 mol% or less by copolymerization other than a hydroxyl group. ,
These may be selected or mixed according to the compatibility with the aqueous alkali silicate solution and the adhesion to the plastic substrate.

The above-mentioned polyethyleneimine is a polyamine having a branched structure of primary, secondary and tertiary amino groups using ethyleneimine as a starting material. In particular, the primary amino groups have high reactivity with plastic materials due to their high reactivity. It is known that the adhesiveness is excellent. Polyethyleneimine having a molecular weight of 300 to 100,000 is suitable for use in the present invention.

A known method can be used for mixing the alkali metal polysilicate and the water-soluble polymer, and is not particularly limited. The mixing ratio of SiO2 in the alkali metal polysilicate is high in consideration of gas barrier properties, flexibility and water resistance.
The weight ratio of (silica component) / water-soluble polymer is 50/50.
It is preferably in the range of 99.99 / 0.01.
When the content of the water-soluble polymer is 50% by weight or more, the gas barrier property is deteriorated due to moisture absorption of the water-soluble polymer.

As a method of imparting a water vapor barrier property by drying at a low temperature, sodium, potassium, calcium,
By introducing magnesium, sulfur, phosphorus, nitrogen and the like, the densification of the silicon oxide film is promoted and the water vapor barrier property is improved. Because the base material is a plastic material, adhesion, flexibility, oxygen barrier properties, and water vapor barrier properties due to short-time low-temperature drying due to problems such as adhesion, flexibility, stability when flying, and prevention of elution when moisture is absorbed. Most preferably, nitrogen is introduced by a nitrogen compound such as an amine containing an amino group-containing silane coupling agent as an organic component.

Next, a film in which a nitrogen compound is mixed with lithium polysilicate will be described. As a method for introducing nitrogen into lithium polysilicate, a gas introduction method in which dry nitrogen gas or ammonia gas is used to permeate water vapor by heating or pressurizing, or a solid or liquid material is directly dissolved in an aqueous alkali silicate solution at room temperature However, the latter method is characterized in that it can be dissolved and diffused with a simple stirring device and that the amount of nitrogen introduced can be easily controlled.

Examples of the nitrogen compound include ammonia, halogenoamine, dihalogenoamine, nitrogen halide, metal amide, metal imide, metal nitride, amines, ammonium salt, alkyl ammonium salt, dialkyl ammonium salt, and trialkyl ammonium salt. , Tetraalkylammonium salts, hydrogen azide, metal azides, hydrazine, hydradium salts, hydroxylamine, hydroxylammonium salts, nitrates, hyponitrites, nitroxylates, nitrites, peroxonitrites, peroxonitrites, nitrogen halides, Nitrogen halide, nitrosyl halide, nitrile halide, halogen nitrate, cyanide, cyanate, thiocyanate, phosphorus nitride, nitrogen sulfide or derivatives thereof are included, but stability, safety, environmental friendliness, price, Compatibility, film strength of the alkali silicate aqueous solution, flexibility and the like are taken into consideration shrinkage prevention, amines can be introduced hydrocarbon residue which is rich in flexibility and readily soluble in an aqueous alkaline solution is more preferable.

The above-mentioned amines are compounds in which a hydrogen atom of ammonia is replaced by a hydrocarbon residue, and the amino group (N
There are a primary amine having H ₂ —), a secondary amine having an imino group (—NH—), a tertiary amine and a quaternary ammonium salt in which all hydrogens are substituted, and a polyamine having many of these functional groups. Also included are ethyleneimine-based polymers such as polyethyleneimine, aminoethylated resins, and aziridinyl group-containing compounds. Also, N- (2-aminoethyl) 3 is an amino group-containing silane coupling agent which is a monoamine or diamine having an alkoxysilyl group.
-Aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane and the like. Even if these are directly introduced, they are hydrolyzed in an aqueous solution before introduction and silanolized. Either may be introduced after the introduction.

As described above, the above-mentioned lithium polysilicate into which a nitrogen compound has been introduced is further used for the purpose of improving film formation stability during coating and drying, stability after film formation, oxygen barrier properties, and flexibility. Such a water-soluble polymer may be introduced. By introducing these in an appropriate amount depending on the nitrogen compound used, the above-mentioned high function can be imparted without hindering the characteristics of the lithium polysilicate and the nitrogen compound.

Films formed from alkali silicates (water glass), including lithium polysilicate, have a whitening phenomenon (eflorescence) in which the film reacts with carbon dioxide gas or moisture in the air over time to whiten the film. As means for solving these, metal powder and polyvalent metal oxide, polyvalent metal hydroxide, phosphate, and the like in alkali polysilicate
Methods for adding and dispersing inorganic compound particles such as borates are known.
It may be added as needed to the extent that the transparency is not reduced. Also,
The same effect can be obtained to some extent by adding a nitrogen compound such as an amine containing an amino group-containing silane coupling agent, or a water-soluble polymer such as a saccharide or polyvinyl alcohol.

It is also possible to combine lithium polysilicate with inexpensive sodium polysilicate or potassium polysilicate, which is known to have water resistance, and to reduce the price without impairing the gas barrier function of lithium polysilicate. An alkali metal polysilicate having characteristics such as water resistance can be obtained. When an alkali metal other than lithium is added, the molar ratio of Li ₂ O / M ′ ₂ O (M ′ is an alkali metal other than lithium) is preferably 1 or more in consideration of gas barrier properties.

As described above, a wide range of alkali metal polysilicates having a molar ratio n of 1 to 20 represented by M ₂ O · nSiO ₂ (M is lithium or a plurality of alkali metals containing lithium) and nitrogen such as amines By adding a compound and a water-soluble polymer such as a saccharide or polyvinyl alcohol as appropriate, film formation, flexibility and crack resistance due to low shrinkage can be imparted, and not only in oxygen barrier properties but also in water vapor barrier properties. It can have an advanced gas barrier function.

A known method can be used for mixing the alkali metal polysilicate with the nitrogen compound or the water-soluble polymer, and is not particularly limited. Further, the mixing ratio is preferably 50% or more by weight of SiO ₂ (silica component) in the alkali metal polysilicate from the viewpoint of gas barrier properties, flexibility and water resistance of the film, and the like. This is because when the content of SiO ₂ (silica component) is less than 50%, the gas barrier property is reduced due to moisture absorption of the nitrogen compound and the water-soluble polymer.

In general, the gas barrier coating is preferably coated so as to have a thickness after drying of 0.01 to 100 μm, more preferably 0.1 to 100 μm.
01 to 10 μm. 0.01 μm
In the following cases, it is difficult to obtain a uniform coating film,
If it exceeds, the film is liable to be broken and there is a problem because it is uneconomical.

As a method for forming the gas barrier film, a usual wet coating method can be used. For example, dipping, roll coating, gravure coating, reverse coating, air knife coating, comma coating, die coating, screen printing, spray coating, gravure offset, and the like can be used. The coating is applied to one or both surfaces of the substrate by using these coating methods. The drying method for drying is a known and commonly used drying method such as hot air drying, hot roll drying, and infrared irradiation, and is not particularly limited.

Since the polyester film and the polyamide film have a surface wetting tension of about 60 dyne / cm by the surface modification treatment such as corona discharge treatment which is generally used on the surface of the above-mentioned plastic substrate, the present invention provides A coating liquid having a high surface tension such as an alkali silicate aqueous solution used for the gas barrier coating layer can be directly applied, but a polyolefin film represented by a polypropylene film or the like can only be obtained up to about 42 dyne / cm. It cannot be applied directly.

The anchor coat layer of the present invention is provided on one side or both sides of the base material made of the above plastic material, and is provided for the purpose of enhancing the film forming property and adhesion of the gas barrier coating layer. In the conventional surface modification treatment described above, not only polyolefin-based films for which sufficient surface wetting tension cannot be obtained, but also found in polyester films and the like,
An effect of preventing substrate damage (breaking of polymer chains) due to elution of an alkali component from the gas barrier film during formation of the gas barrier film and storage in a high-humidity environment can also be obtained.

The above-mentioned anchor coat layer is provided by coating. However, in consideration of the surface smoothness, it is more preferable that the material is dissolved in water or an organic solvent and provided by wet coating. Examples of the material include polyethyleneimine or a derivative thereof, a silane coupling agent, an organic titanate, polyacryl, polyester, polyurethane, polycarbonate, polyurea, polyamide, polyolefin-based emulsion, polyimide, melamine, and phenol. Then, it is preferable that the resin does not have an ester bond in the main chain, and it is more preferable that an organic polymer having at least one urethane bond and at least one urea bond is contained in consideration of adhesion at low temperature. Even if the urethane bond and the urea bond use a polymer previously introduced in the polymerization stage, a polyol such as an acrylic or methacrylic polyol and an isocyanate compound having an isocyanate group, or an amine resin having an amino group and an epoxy resin and a glycidyl group may be used. An urethane bond may be formed by reacting an epoxy compound or the like having the same, or a urea bond may be formed by reacting an isocyanate compound with water or an amine resin having an amino group. As an additive,
An inorganic component may be introduced with a silane coupling agent, colloidal silica, organic titanate, etc. in consideration of the adhesion to the gas barrier coating layer, and a surfactant such as a quaternary ammonium salt to improve wettability. An amine resin such as a tertiary amine may be introduced. These may be introduced as a main skeleton in the polymer polymerization stage, may be reacted at the side chain terminal, or may be directly added directly to a diluted solution in use.

The thickness of the anchor coat layer is not particularly limited. However, if the thickness is less than 0.001 μm, adhesion or film forming property cannot be obtained, and if it is more than 5 μm, it is uneconomical. Generally, the range of 0.005 to 1 μm is practical and more preferable. As a forming method, an ordinary wet coating method such as a dipping method, a roll coating, a gravure coating, a reverse coating, an air knife coating, a comma coating, a die coating, a screen printing method, a spray coating, and a gravure offset method can be used. The coating is applied to one or both surfaces of the substrate by using these coating methods. The drying method for drying is a known and commonly used drying method such as hot air drying, hot roll drying, and infrared irradiation, and is not particularly limited.

Further, a practical laminated structure as a packaging material can be provided on the gas barrier coating surface or on the opposite surface. For example, it is a printing layer or a heat sealing layer such as a thermoplastic resin. Further, in order to increase the adhesion between the gas barrier coating layer and the printing layer, an adhesion layer (overcoat layer) can be provided between the surface of the gas barrier coating layer and the printing layer.

The printing layer is for the purpose of merchantability, aesthetics, display display effect, etc. of the contents to be packaged, and is made of urethane, acrylic, nitrocellulose, polyamide,
A layer composed of a printing ink in which additives such as a pigment, a vehicle, a plasticizer, a drying agent, and a stabilizer are added to an ink binder resin such as a polyvinyl chloride-based resin, and characters, pictures, and the like are formed. ing. As a forming method, for example, a well-known printing method such as an offset printing method, a gravure printing method, or a silk screen printing method, or a well-known coating method such as a roll coat, a knife edge coat, or a gravure coat can be used. The thickness is appropriately selected in the range of 0.1 to 2.0 μm.

When a multi-color gravure printing machine or the like is used for laminating the printing layers, the gas barrier coating layer may be provided first, and then the printing layer may be provided in-line using the same printing machine.

The heat seal layer is used for an adhesive portion when forming a bag-like package or the like. For example, polyethylene, polypropylene, ethylene-vinyl acetate copolymer, ethylene-methacrylic acid copolymer, ethylene Resins such as methacrylic acid ester copolymers, ethylene-acrylic acid copolymers, ethylene-acrylic acid ester copolymers, and metal crosslinked products thereof; The thickness is determined according to the purpose, but is generally in the range of 15 to 200 μm.

The heat sealing layer may be formed by a dry laminating method in which a film-like material made of the above resin is bonded using a two-component curable urethane-based adhesive, or a non-solvent type in which the film is bonded using a solventless adhesive. Any of a dry lamination method, an extrusion lamination method in which the above-described resin is heated and melted, and extruded in a curtain shape, and the like can be formed by a known lamination method.

The gas barrier laminate according to the present invention will be further described with reference to specific examples.

<Experiment 1><Preparation of Gas Barrier Coating Solution> A) Lithium silicate aqueous solution (Li2O.nSiO
2, n = about 4.5 molar ratio)
As a water-soluble polymer, polyvinyl alcohol (trade name “PVA117” manufactured by Kuraray Co., Ltd.), saponification degree: about 99 mol
%, The degree of polymerization of about 1700) is dissolved in SiO2 /
The mixture was added so as to become 90/10 in terms of the weight of the water-soluble polymer, followed by stirring to obtain a composite liquid A.

B) Lithium silicate aqueous solution (Li2O
(NSiO2, n = about 4.5 mole ratio) in a solid content adjusted aqueous solution, as a water-soluble polymer, silanol group-modified polyvinyl alcohol (trade name "R-113" manufactured by Kuraray Co., Ltd.)
0 ”, a saponification degree of about 99 mol%)
The mixture was added so as to be 90/10 in terms of the weight of iO2 / water-soluble polymer and stirred to obtain a composite liquid B.

C) Lithium silicate aqueous solution (Li2O
In an aqueous solution having a solid content adjusted to nSiO 2, n = about 4.5 mol), an amino group-modified polyvinyl alcohol (trade name “C-118” manufactured by Kuraray Co., Ltd.) as a water-soluble polymer, and a saponification degree of about 99 mol% ) Was dissolved in SiO2 /
The mixture was added so that the weight became 90/10 in terms of the weight of the water-soluble polymer, and the mixture was stirred to obtain a composite liquid C.

D) Lithium silicate aqueous solution (Li2O
A carboxyl group-modified polyvinyl alcohol (trade name “KM -1” manufactured by Kuraray Co., Ltd.) as a water-soluble polymer in an aqueous solution having a solid content of (nSiO 2, n = about 4.5 mol ratio)
18 ", a saponification degree of about 97 mol%) was added thereto so that the weight ratio of SiO2 / water-soluble polymer was 90/10, and the mixture was stirred to obtain a composite liquid D.

E) Lithium silicate aqueous solution (Li2O
In an aqueous solution having an adjusted solid content of nSiO 2, n = about 4.5 mole ratio, as a water-soluble polymer, cellulose (hydroxyethyl cellulose, trade name, manufactured by Tokyo Chemical Industry Co., Ltd., 450
An aqueous solution in which 0-6500 cps (2% water) was dissolved was added so as to be 90/10 in terms of weight of SiO2 / water-soluble polymer, and the mixture was stirred to obtain a composite liquid E.

F) Lithium silicate aqueous solution (Li2O
(NSiO 2, n = about 4.5 mole ratio) to obtain a single solution F of an aqueous solution whose solid content was adjusted.

G) JIS standard No. 3 water glass aqueous solution (Na
2O.nSiO2, n = approximately 3.1 to 3.3 molar ratio), an aqueous solution having a solid content adjusted, polyvinyl alcohol (trade name "PVA117" manufactured by Kuraray Co., Ltd.) as a water-soluble polymer,
An aqueous solution in which a saponification degree of about 99 mol% and a polymerization degree of about 1700) was dissolved was converted to a solution of 90/90 in terms of weight of SiO2 / water-soluble polymer.
Then, the mixture was stirred to obtain a composite liquid G.

<Example 1> A gravure coat of a composite liquid A as a gas barrier coating was applied on one surface of a substrate “Lumirror P60” (trade name, manufactured by Toray Industries, Inc.) (biaxially stretched polyethylene terephthalate film (PET) 12 μm thick) as a substrate. According to the method, it passes through a hot-air drying oven set at 80 ° C and has a thickness of about 1 µm.
Was formed to produce a gas barrier laminate of the present invention.

<Example 2> A gas barrier laminate of the present invention was produced in the same manner as in Example 1, except that the composite liquid B was used.

<Example 3> A gas barrier laminate of the present invention was produced in the same manner as in Example 1, except that the composite liquid C was used.

Example 4 A gas barrier laminate of the present invention was produced in the same manner as in Example 1, except that the composite liquid D was used.

Example 5 A gas barrier laminate of the present invention was produced in the same manner as in Example 1, except that the composite liquid E was used.

Comparative Example 1 A silica coating laminate was prepared in the same manner as in Example 1 except that the simple liquid F was used.

Comparative Example 2 A silica coating laminate was prepared in the same manner as in Example 1, except that the composite solution G was used.

(Evaluation) Each of the laminates of the example and the comparative example was evaluated.
Table 1 shows (1) oxygen permeability (cm³/ M ² ・ Da
y ・ atm), (2) Coating appearance, (3) Cellophane tape
The evaluation results of the adhesion are shown.

(1) Oxygen Permeability Oxygen Permeability Measurement Apparatus (manufactured by MOCON, OXTRAN-
2/20) in an atmosphere at 30 ° C. and 80% RH.

(2) Appearance of Coating Film After coating and drying, the gas barrier coating surface was visually observed, and the presence or absence of minute cracks on the coating surface was confirmed.

(3) Adhesion of cellophane tape A cellophane tape was adhered to the surface on which the film was formed, and then peeled off, and it was visually observed whether the film was peeled off.

Table 1 shows the results.

[0083]

[Table 1]

In Comparative Example 1, since the water-soluble polymer was not added, the shrinkage of the coating film was large, uniform formation was not possible, and cracks occurred in the film itself. Comparative Example 2
Since sodium silicate was used instead of lithium, a decrease in gas barrier properties due to moisture absorption under high humidity conditions, which is a property of polyvinyl alcohol, was observed. In the examples, a gas barrier property effective for packaging applications was obtained, and a uniform coating without cracks in the coating and sufficient adhesion were obtained.

<Experiment 2><Preparation of gas barrier coating solution> H) Lithium silicate aqueous solution (Li2O.nSiO
A silane coupling agent (trade name “Sila Ace S320” manufactured by Chisso Corp., N- (2-aminoethyl) 3-aminopropyltriamine) was added as a nitrogen compound to an aqueous solution whose solid content was adjusted to 2, n = about 5 mol ratio). An aqueous solution in which methoxysilane was dissolved was added so as to be 90/10 in terms of the weight of the hydrolyzate of the SiO2 / silane coupling agent, followed by stirring to obtain a composite liquid H.

I) Lithium silicate aqueous solution (Li2O
An aqueous solution in which a silane coupling agent (trade name “Silaace S360”, manufactured by Chisso Corporation, 3-aminopropyltrimethoxysilane) is dissolved as a nitrogen compound in an aqueous solution whose solid content has been adjusted to nSiO 2, where n = about 5 mol ratio. To Si
9 by weight conversion of O2 / silane coupling agent hydrolyzate
The mixture was added to be 0/10 and stirred to obtain a composite liquid I.

J) Lithium silicate aqueous solution (Li2O
In an aqueous solution having a solid content adjusted to nSiO2, n = about 5 mole ratio), as a nitrogen compound, polyethyleneimine (trade name "Epomin SP-200" manufactured by Nippon Shokubai Co., Ltd., molecular weight 10)
000) was added so as to be 90/10 in terms of weight of SiO2 / polyethyleneimine, followed by stirring to obtain a composite liquid J.

K) Lithium silicate aqueous solution (Li2O
A silane coupling agent (trade name “Sila Ace S320” manufactured by Chisso Corp.) and N- (2-
An aqueous solution in which (aminoethyl) 3-aminopropyltrimethoxysilane) is dissolved, and a silane-modified polyvinyl alcohol (trade name “R-
2105 ", a degree of saponification of about 98.5 mol%) was added so as to be 85/10/5 in terms of weight of SiO2 / silane coupling agent hydrolyzate / water-soluble polymer, and the mixture was stirred. Liquid K was obtained.

L) A silane coupling agent (trade name “Sila Ace S320” manufactured by Chisso Corporation, N) was added to a lithium potassium silicate aqueous solution (M 2 O · nSiO 2, n = about 5 molar ratio) in which the solid content was adjusted.
Aqueous solution in which-(2-aminoethyl) 3-aminopropyltrimethoxysilane) was dissolved, and silane-modified polyvinyl alcohol (trade name “R-2105” manufactured by Kuraray Co., Ltd.) as a water-soluble polymer; (5 mol%) was dissolved in an aqueous solution containing SiO2 / silane coupling agent hydrolyzate / water-soluble polymer in a weight conversion of 85/10/5, followed by stirring to obtain a composite liquid L.

M) Lithium silicate aqueous solution (Li2O
(NSiO2, n = about 5 mole ratio) to obtain a simple substance solution M of an aqueous solution whose solid content was adjusted.

N) Potassium silicate aqueous solution (K2O.
A silane coupling agent (trade name "Sila Ace S320" manufactured by Chisso Corporation) and N- (2-
An aqueous solution in which (aminoethyl) 3-aminopropyltrimethoxysilane) is dissolved, and a silane-modified polyvinyl alcohol (trade name “R-
2105 ", a degree of saponification of about 98.5 mol%) was added so as to be 85/10/5 in terms of weight of SiO2 / silane coupling agent hydrolyzate / water-soluble polymer, and the mixture was stirred. Liquid N was obtained.

O) Lithium silicate aqueous solution (Li2
(O.nSiO2, n = about 5 mole ratio) in an aqueous solution having adjusted solid content, as a water-soluble polymer, silane-modified polyvinyl alcohol (trade name "R-2105" manufactured by Kuraray Co., Ltd.), saponification degree: about 98.5 mol% ) Is dissolved in SiO
2 / The water-soluble polymer was added so as to be 90/10 in terms of weight, and stirred to obtain a composite liquid O.

<Example 6> As a base material, a composite liquid as a gas barrier film was formed on one surface of a corona-treated surface of “Lumirror P60n” (trade name, manufactured by Toray Industries, Inc., 12 μm thick biaxially stretched polyethylene terephthalate film (PET)). H was passed through a hot air drying oven set at 100 ° C. by a gravure coating method to form a coating having a thickness of about 0.5 μm, thereby producing a gas barrier laminate of the present invention.

<Example 7> A gas barrier laminate of the present invention was produced in the same manner as in Example 6, except that Composite Liquid I was used.

<Example 8> A gas barrier laminate of the present invention was produced in the same manner as in Example 6, except that Composite Liquid J was used.

<Example 9> A gas barrier laminate of the present invention was produced in the same manner as in Example 6, except that the composite liquid K was used.

<Example 10> In Example 6, the composite liquid L
A gas barrier laminate of the present invention was produced in the same manner except that was used.

Comparative Example 3 A silica coating laminate was prepared in the same manner as in Example 6, except that the simple liquid M was used.

Comparative Example 4 A silica coating laminate was prepared in the same manner as in Example 6, except that the composite liquid N was used.

Comparative Example 5 A silica coating laminate was prepared in the same manner as in Example 6, except that the composite liquid O was used.

(Evaluation) Each of the laminates of the example and the comparative example was evaluated.
Table 1 shows (1) oxygen permeability (cm³/ M ² ・ Da
y · atm), (2) water vapor transmission rate (g / m² ・ Da
y), (3) Coating appearance, (4) Cellophane tape adhesion
The evaluation results are shown.

(1) Oxygen Permeability Oxygen Permeability Measurement Apparatus (manufactured by MOCON, OXTRAN-
2/20) in an atmosphere at 30 ° C. and 80% RH.

(2) Water vapor transmission rate Water vapor transmission rate measuring apparatus (PERMAT, manufactured by MOCON)
RAN-3 / 31) at 40 ° C. and 90% RH.

(3) Appearance of Coating The gas barrier coating after coating and drying was visually observed to confirm the state of the coated surface.

(4) Cellophane Tape Adhesion A cellophane tape was applied to the surface on which the film was formed, and then peeled off, and it was visually observed whether the film was peeled.

[0106]

[Table 2]

In contrast to Comparative Example 3, in Comparative Example 3, since the nitrogen compound and the water-soluble polymer were not blended, the shrinkage of the film was large, cracks were generated in the film itself, and the numerical value of the water vapor permeability was also good. Not obtained. In Comparative Example 4, since the alkali metal was potassium alone containing no lithium, the oxygen permeability and the water vapor permeability were not obtained. In Comparative Example 5, the water vapor transmission rate was not obtained because nitrogen was not introduced into the film by mixing only the water-soluble polymer instead of the nitrogen compound. In the examples, effective oxygen barrier properties and water vapor barrier properties for use in packaging were obtained, and a uniform coating having no cracks in the coating and sufficient adhesion were obtained.

<Experiment 3> (Preparation of gas barrier coating solution) A) A silane coupling agent as a nitrogen compound was added to an aqueous solution of lithium silicate aqueous solution (Li ₂ O · nSiO ₂ , n = about 5 mol ratio) whose solid content was adjusted. (Chisso Corporation product name "Sila Ace S32
0 ", an aqueous solution in which N- (2-aminoethyl) 3-aminopropyltrimethoxysilane) was dissolved so as to be 90/10 in terms of the weight of the hydrolyzate of SiO ₂ / silane coupling agent, and stirred, The same coating liquid A as in Experiment 1 above
I got

P) Lithium silicate aqueous solution (Li ₂ O
Silane-modified polyvinyl alcohol (trade name “R-2105” manufactured by Kuraray Co., Ltd.) as a water-soluble polymer in an aqueous solution having a solid content adjusted to nSiO ₂ , n = about 5 mol ratio, and a saponification degree of about 98.5 mol% ) Was dissolved in SiO ₂ /
The mixture was added so as to be 95/5 in terms of weight of the water-soluble polymer, and stirred to obtain a composite liquid P.

Q) Potassium silicate aqueous solution (K ₂ O.
silane-modified polyvinyl alcohol (trade name “R-2105” manufactured by Kuraray Co., Ltd., saponification degree: about 98.5 mol%) as a water-soluble polymer in an aqueous solution having a solid content of (nSiO ₂ , n = about 4 mol ratio) Was dissolved and added so that the weight ratio of SiO ₂ / water-soluble polymer became 95/5, followed by stirring to obtain a composite liquid Q.

(Adjustment of Adhesion Layer (Anchor Coat Layer)) R
) Acrylic resin (trade name “LR” manufactured by Mitsubishi Rayon Co., Ltd.)
209 ”) with ethyl acetate, and then an isocyanate curing agent (trade name“ Coronate L ”manufactured by Nippon Polyurethane Industry Co., Ltd.) is added so as to have a solid content of 80/20 parts by weight, followed by stirring to modify the surface. A treatment liquid R was obtained.

S) Polyethyleneimine (trade name “Epomin P-1000” manufactured by Nippon Shokubai Co., Ltd.) was adjusted to a solid content of 1% with a dilute solution of water / methanol = 20/80 parts, and the surface was modified. The quality treatment liquid S was obtained.

(Example 11) As a base material, East Cello Co., Ltd.
Drying with hot air at 80 ° C set by gravure coating method on the corona discharge treated surface of "HE-1" (trade name: high moisture-proof type biaxially oriented polypropylene film, 20 µm thick) Thickness 0 through oven.
A coating having a thickness of 01 to 0.05 μm was formed. Next, the composite liquid A (similar to the liquid A in Experiment 1) was passed through a hot air drying oven set at 80 ° C. as a gas barrier coating by a gravure coating method to form a coating having a thickness of about 0.5 μm. The body was made.

Example 12 A gas barrier laminate of the present invention was produced in the same manner as in Example 11, except that the composite liquid P was used.

(Example 13) A gas barrier laminate of the present invention was produced in the same manner as in Example 11, except that the surface modification treatment liquid S was used.

(Example 14) [0116] The present invention was carried out in the same manner as in Example 11, except that "YB22" (trade name, a high moisture-proof type biaxially oriented polypropylene film having a thickness of 22 µm) manufactured by Toray Industries, Inc. was used as the base material. Was produced.

(Example 15) In Example 11, as a substrate, "HC-OP" (trade name, manufactured by Tocelo Co., Ltd.)
m thickness) was used in the same manner as above, except that the gas barrier laminate of the present invention was produced.

(Comparative Example 6) A silica coating laminate was produced in the same manner as in Example 11, except that the surface modification treatment liquid was not used.

Comparative Example 7 A silica coating laminate was prepared in the same manner as in Example 11, except that the composite liquid Q was used.

(Comparative Example 8) As a physical property of a base material, "HE-1" (trade name, manufactured by Tocelo Co., Ltd.) (a highly moisture-proof type biaxially oriented polypropylene film having a thickness of 20 µm) was used as a sample of Comparative Example 8.

(Evaluation) Each of the laminates of Examples and Comparative Examples was evaluated.
Table 3 shows (1) oxygen permeability (cm³/ M ²・ Day
Atm), (2) water vapor transmission rate (g / m²・ Da
y), (3) Coating appearance, (4) Cellophane tape adhesion
The evaluation results are shown.

(1) Oxygen Permeability Oxygen Permeability Measurement Apparatus (manufactured by MOCON, OXTRAN-
2/20) in an atmosphere of 30 ° C. and 90% RH.

(2) Water Vapor Transmission Rate A water vapor transmission rate measuring apparatus (PERMAT, manufactured by MOCON)
RAN-3 / 31) at 40 ° C. and 90% RH.

(3) Coating Appearance The gas barrier coating surface after coating and drying was visually observed to confirm the state of the coating surface.

(4) Cellophane Tape Adhesion A cellophane tape was adhered to the surface on which the film was formed, and then peeled off, and the film was visually observed for peeling.

[0126]

[Table 3]

In contrast, in Comparative Example 6, since the surface of the base material was not subjected to the modification treatment, the film was repelled immediately after the application of the composite liquid, and a film could not be formed. In Comparative Example 7, since the alkali metal was potassium alone containing no lithium, a high oxygen permeability was not obtained. Comparative Example 8
Does not form a lithium polysilicate coating, and thus cannot obtain an oxygen permeability. In the examples, a well-balanced oxygen barrier property and water vapor barrier property were obtained for packaging applications, and a uniform coating without cracks and sufficient adhesion were obtained.

[0128]

As described above, according to the present invention, it has a high oxygen barrier property even under high temperature and high humidity corresponding to the summer environment in Japan, a high water vapor barrier property for protecting the moisture absorption of the contents, and further has an adhesive property and Since it is excellent in processability, transparency, flexibility and cost performance, it can be said that it can be widely used in the packaging field.

Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat II (Reference) C08L 29/04 C08L 29/04 79/02 79/02 (72) Inventor Ryuyoshi Matsuo 1-5 Taito, Taito-ku, Tokyo No. 1 Letterpress Printing Co., Ltd. (72) Inventor Takeshi Kintaka 1-5-1, Taito, Taito-ku, Tokyo Letterpress Printing Co., Ltd. F-term (reference) 3E086 AB02 BA04 BA15 BA24 BA40 BB02 BB05 CA01 CA28 CA31 4F006 AA12 AA35 AB03 AB20 AB24 AB33 AB37 AB65 AB67 AB74 AB76 BA05 CA07 DA04 4F100 AA17B AA20B AA33B AH03B AH06B AJ03B AK01A AK01B AK03A AK21B AK25G AK31B AK42 AK51G BA02 BA13 EH20A EJ38A EJ65 GB15 GB23 GB41 GB66 JB09B JD02B JD03 JD04 JD04A JK06 JK13 JK17 JL01 JL11 JN01 YY00B 4J002 AA001 BE021 CM011 DJ006 EX077 FD206 FD207 GG02

Claims (11)

[Claims] 1. A method according to claim 1, wherein one side or both sides of a base material made of a plastic material is provided with M ₂ O · nSiO ₂ (M is lithium or a plurality of alkali metals containing lithium, and n is 1 to 1 in molar ratio).
A gas barrier film comprising: an alkali metal polysilicate represented by the formula (20) and a gas barrier coating mainly composed of a water-soluble polymer. 2. A method according to claim 1, wherein one side or both sides of a base material made of a plastic material is provided with M ₂ O · nSiO ₂ (M is lithium or a plurality of alkali metals containing lithium, and n is a mole ratio of 1 to 1).
20), and a gas barrier film comprising a gas barrier coating having a nitrogen compound as a main component. 3. One or both sides of a base material made of a plastic material, M ₂ O · nSiO ₂ (M is lithium or a plurality of alkali metals containing lithium, and n is a mole ratio of 1 to 1).
20), and a gas barrier film comprising a water-soluble polymer and a nitrogen compound as main components. 4. The gas barrier film according to claim 1, wherein the water-soluble polymer is at least one selected from saccharides, polyvinyl alcohol, polyethylene imine, and derivatives thereof. 5. The weight ratio of SiO ₂ (silica component) / water-soluble polymer in the gas barrier coating is 50 / 50-9.
The gas barrier film according to claim 1, wherein the gas barrier film is in a range of 9.9 / 0.01. 6. The gas barrier film according to claim 2, wherein the nitrogen compound is an amine containing an amino group-containing silane coupling agent. 7. The gas barrier film according to claim 1, wherein an anchor coat layer is provided between the substrate made of the plastic material and the gas barrier coating. 8. The gas barrier film according to claim 7, wherein said anchor coat layer comprises an acrylic resin and an isocyanate compound as main components. 9. The gas barrier film according to claim 1, wherein the substrate made of the plastic material is a polyolefin. 10. The gas barrier film according to claim 9, wherein the substrate made of the polyolefin imparts moisture resistance. 11. The gas barrier film according to claim 9, wherein the substrate made of the polyolefin is a biaxially stretched film having a multilayer structure of two or more layers by coextrusion.