JP2019107803A - Barrier film - Google Patents

Abstract

To provide a barrier film excellent in interlayer adhesion and gas barrier properties.SOLUTION: The barrier film according to the present invention includes a second inorganic oxide vapor deposition layer, a barrier coat layer, a first inorganic oxide vapor deposition layer, a substrate film, and a third inorganic oxide vapor deposition layer in this order. The barrier coat layer is a cured film of a hydrolysis product of a metal alkoxide and a water-soluble polymer. The first inorganic oxide vapor deposition layer is an aluminum oxide vapor deposition film.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a barrier film, and more particularly, to a second inorganic oxide deposited layer, a barrier coat layer, a first inorganic oxide deposited layer, a base film, and a third inorganic oxide deposited. The present invention relates to a barrier film provided with layers in this order.

  Conventionally, as a barrier material against oxygen or water vapor, an inorganic oxide such as silicon oxide or aluminum oxide is formed on a film substrate by vacuum evaporation, sputtering, ion plating, chemical vapor deposition, etc. Transparent gas barrier films are attracting attention. As a barrier film, a barrier film provided with a metal foil with aluminum foil or the like has also been used because of its excellent gas barrier properties, but it can not be used for microwave ovens, and is opaque because it is opaque. There was a problem of being inferior.

  In recent years, liquid paper containers having excellent gas barrier properties have been developed for filling and packaging liquids such as beverages, food and drink such as liquor, juice, mineral water and liquid seasonings, and chemical products. As such a liquid paper container, for example, one formed by box-forming a laminated material for paper container having an outermost layer, a paper base layer, an adhesive layer, a barrier layer and an innermost layer is mentioned. Here, as a barrier layer, the barrier film etc. which provided the vapor deposition film of the inorganic oxide in one side of base films, such as a resin film, are used, for example (patent document 1).

Japanese Patent Laid-Open No. 2002-154524

  However, since the vapor-deposited film of inorganic oxide is a non-flexible thin film, a crack or the like is easily generated by heat or pressure applied from the outside during processing such as lamination or box making, and the gas barrier property is impaired. There was a problem that. On the other hand, it has been studied to prevent the occurrence of cracks and the like by providing a gas barrier coating film on the vapor deposited film of the inorganic oxide.

  Moreover, in order to obtain the self-supporting property and strength of a container, it is required to use the thing of a certain thickness as a paper base material used in the laminated material for paper containers. However, a paper substrate having a sufficient thickness is likely to cause delamination when sufficient interlayer adhesion strength is not obtained when laminating with another substrate via an adhesive layer. In particular, when laminating a paper substrate with a gas barrier coating film of a barrier film, sufficient interlayer adhesion strength can not be obtained, and punching of a laminated material for paper containers into a blank plate in a box making process, creased line forming There has been a problem that peeling between the barrier film and the paper substrate or the resin layer resulting therefrom occurs in the embossing. Further, in the case of a system in which a roll-like laminated material for paper containers is boxed in-line, there is a similar problem of peeling in steps such as bending, embossing and cutting. Furthermore, there existed a problem that sufficient gas barrier property was not exhibited by it either.

  The present invention was made in view of the above background art, and an object thereof is to provide a barrier film excellent in interlayer adhesion and gas barrier properties.

  The inventors of the present invention conducted intensive studies to solve the above problems, and as a result, in the barrier film, a second inorganic oxide deposited layer, a specific barrier coat layer, a specific first inorganic oxide deposited layer, and a substrate By laminating | stacking a film and the 3rd inorganic oxide vapor deposition layer in order, it discovered that the said subject was solvable. The present invention has been completed based on such findings.

That is, according to one aspect of the present invention,
A barrier film comprising a second inorganic oxide deposited layer, a barrier coat layer, a first inorganic oxide deposited layer, a base film, and a third inorganic oxide deposited layer in this order. ,
The barrier coat layer is a cured film of a hydrolysis product of a metal alkoxide and a water-soluble polymer,
A barrier film is provided, wherein the first inorganic oxide deposited layer is an aluminum oxide deposited film.

  In the above aspect of the present invention, the aluminum oxide vapor deposition film of the first inorganic oxide vapor deposition layer preferably has a thickness of 5 to 15 nm.

  In the above aspect of the present invention, the second inorganic oxide deposited layer is preferably an aluminum oxide deposited film.

  In the above aspect of the present invention, the third inorganic oxide deposited layer is preferably an aluminum oxide deposited film.

  In the above aspect of the invention it is preferred that the barrier film is for a paper container.

According to another aspect of the invention,
Paper container laminate comprising an outermost layer, a paper base layer, a first heat-fusible resin layer, a barrier layer, a second heat-fusible resin layer, and an innermost layer in this order Materials,
The laminated material for paper containers in which the said barrier layer consists of said barrier film is provided.

  In another aspect of the present invention, the heat-fusible resin constituting the heat-fusible resin layer is preferably an ethylene-based polymer having a carboxyl group or an acid anhydride group in the molecule.

  In another aspect of the present invention, the second inorganic oxide deposition layer of the barrier film is in contact with the first heat-fusible resin layer, and the third inorganic oxide deposition layer of the barrier film is It is preferable to be in contact with the second heat-fusible resin layer.

  In another aspect of the present invention, a resin layer is provided between the paper base layer and the first heat-fusible resin layer and / or between the second heat-fusible resin layer and the innermost layer. It is preferable to further comprise

According to yet another aspect of the invention,
There is provided a paper container produced by box-forming the above-mentioned laminate material for paper container.

  ADVANTAGE OF THE INVENTION According to this invention, the barrier film excellent in interlayer adhesiveness and gas-barrier property can be provided. Moreover, the laminated material for paper containers using such a barrier film can be provided. Furthermore, it is possible to provide a liquid paper container formed by box-forming such a laminated material for paper containers.

It is a schematic sectional drawing which showed one Embodiment of the barrier film of this invention. BRIEF DESCRIPTION OF THE DRAWINGS It is the schematic sectional drawing which showed one Embodiment of the laminated material for paper containers of this invention.

<Barrier film>
The barrier film according to the present invention comprises a second inorganic oxide deposited layer, a barrier coat layer, a first inorganic oxide deposited layer, a base film, and a third inorganic oxide deposited layer in this order. Become. The barrier film having such a layer configuration is excellent in interlayer adhesion and excellent in gas barrier properties. Such a barrier film can be suitably used as a barrier layer of various containers and the like which are required to have gas barrier properties and strong adhesiveness, and can be suitably used, for example, as a barrier layer of a laminated material for paper containers. .

Barrier film, the oxygen permeability was measured under the environment of temperature 23 ° C. and humidity 90 RH% is preferably not more than 2.5cc ^/ m 2 · day, more preferably be less 1.0cc ^/ m 2 · day More preferably, it is 0.5 cc / m ² · day or less. If the oxygen permeability of the barrier film satisfies the above numerical range, it has suitable oxygen barrier properties, and therefore, when used as a barrier layer of a paper container, it is possible to suppress an adverse effect on the contents of the paper container .

The barrier film preferably has a water vapor permeability measured according to JIS K 7129 of 3.0 g / m ² · day or less, more preferably 1.0 g / m ² · day or less, still more preferably 0 .5 g / m ² · day or less. If the water vapor transmission rate of the barrier film satisfies the above numerical range, it has suitable water vapor barrier properties, and therefore, when used as a barrier layer of a paper container, adverse effects on the contents of the paper container can be suppressed .

  The layer structure of the barrier film of the present invention will be described with reference to the drawings. The barrier film 10 shown in FIG. 1 comprises a first inorganic oxide deposited layer 13 on one surface of a base film 11, and further comprises a barrier coat layer 15 on the first inorganic oxide deposited layer 13, and further A second inorganic oxide deposited layer 12 is provided on the barrier coat layer 15. In addition, the third inorganic oxide vapor deposition layer 14 is provided on the other surface of the base film 11. Hereinafter, each layer which comprises the barrier film of this invention is demonstrated.

(Base film)
The base film used in the barrier film of the present invention is not particularly limited, but it is excellent in chemical or physical strength, withstands the conditions for forming a deposited film of inorganic oxide, etc., and its film characteristics It is possible to use a film of resin that can be held well without loss of Specifically, for example, polyolefin resin such as polyethylene resin or polypropylene resin, cyclic polyolefin resin, polystyrene resin, acrylonitrile-styrene copolymer (AS resin), acrylonitrile-butadiene-styrene copolymer (ABS) Resin), poly (meth) acrylic resin, polycarbonate resin, polyvinyl alcohol resin, saponified ethylene-vinyl ester copolymer, polyester resin such as polyethylene terephthalate and polyethylene naphthalate, and polyamide resin such as various nylons Films of various resins such as polyurethane resins, acetal resins, and cellulose resins can be used. In the present invention, among the films of the above-mentioned resins, it is particularly preferable to use a film of a polyester resin, a polyolefin resin or a polyamide resin. The base film may be any of an unstretched film of the above-mentioned resin, a film of a resin stretched in a uniaxial direction or biaxial direction, and the like.

  In the present invention, as the film of the above-mentioned various resins, for example, one or more of the above-mentioned various resins are used and manufactured by an extrusion method, cast molding method, T-die method, cutting method, inflation method, etc. A method of forming a film of the above-described various resins alone using a film forming method, or a method of forming a multilayer coextrusion film using two or more of various resins, and further, of two or more Films of various resins are manufactured by using resin and mixing and film forming before film forming, etc. Further, if necessary, for example, using a tenter system or a tubular system etc. It is possible to use various resin films formed by uniaxially or biaxially stretching.

  In the present invention, the film thickness of various resin films is preferably about 6 to 2000 μm, more preferably about 9 to 100 μm.

  One or more of the above-mentioned various resins are used, and in forming the film, for example, processability of the film, heat resistance, weather resistance, mechanical properties, dimensional stability, antioxidative property, slipperiness, separation Various plastic additives, additives and the like can be added for the purpose of improving and modifying the shape, flame retardancy, anti-moldability, electrical characteristics, strength and the like. Depending on the purpose, a small amount to several tens percent can be added arbitrarily.

  In the above, as a general additive, for example, a lubricant, a crosslinking agent, an antioxidant, an ultraviolet absorber, a light stabilizer, a filler, a reinforcing agent, an antistatic agent, a pigment and the like can be used, and further In addition, reforming resins and the like can also be used.

  In the present invention, the base film may be subjected to surface treatment in advance before forming the inorganic oxide deposited film on the above base film. By this, the adhesiveness with the inorganic oxide vapor deposition film can be improved. Similarly, surface treatment may be performed on the vapor deposition layer to improve the adhesion to the gas barrier coating film. Examples of such surface treatment include corona discharge treatment, ozone treatment, low temperature plasma treatment using oxygen gas or nitrogen gas, glow discharge treatment, pretreatment such as oxidation treatment using chemicals, and the like.

  Moreover, a primer coating agent, an undercoat agent, or a vapor deposition anchor coating agent etc. can be apply | coated arbitrarily, and it can also be set as surface treatment. Examples of the coating agent include polyester resins, polyamide resins, polyurethane resins, epoxy resins, phenol resins, (meth) acrylic resins, polyvinyl acetate resins, and polyolefin resins such as polyethylene and polypropylene. A resin composition containing a resin, a copolymer or a modified resin thereof, a cellulose resin or the like as the main component of the vehicle can be used.

  Among such surface treatments, it is particularly preferable to perform corona treatment or plasma treatment. For example, as plasma processing, there is plasma processing which performs surface modification using plasma gas generated by ionizing gas by arc discharge. As the plasma gas, in addition to the above, inorganic gases such as oxygen gas, nitrogen gas, argon gas, helium gas and the like can be used. For example, by performing the plasma treatment in-line, it is possible to remove moisture, dust and the like on the surface of the substrate film and to enable surface treatment such as smoothing and activation of the surface. In addition, after the vapor deposition, plasma treatment can be performed to improve adhesion. In the present invention, as the plasma processing, it is preferable to perform plasma discharge processing in consideration of plasma output, type of plasma gas, supply amount of plasma gas, processing time, and other conditions. Further, as a method of generating plasma, an apparatus such as direct current glow discharge, high frequency discharge, microwave discharge and the like can be used. Plasma treatment can also be performed by atmospheric pressure plasma treatment.

(Inorganic oxide deposited layer)
The deposition layer constituting the barrier film according to the present invention is a deposition film formed by a chemical vapor deposition method (CVD method) or a physical vapor deposition method (PVD method). The barrier film is provided with the first to third inorganic oxide deposited layers, and the first inorganic oxide deposited layer mainly exhibits a barrier function as a barrier film, and the second and second located on both surfaces of the barrier film The inorganic oxide deposited layer 3 plays a role in improving the adhesion to the heat-fusible resin layer when forming the following laminated material while exhibiting a barrier function.

  In the present invention, the first inorganic oxide deposited layer is an aluminum oxide deposited film. The second and third inorganic oxide deposited layers are not particularly limited, but oxides such as silicon, aluminum, magnesium, calcium, potassium, tin, sodium, boron, titanium, lead, zirconium, yttrium and the like The vapor deposition film of can be used. In particular, the second and third inorganic oxide deposition layers are preferably aluminum oxide or silicon oxide deposition films, and more preferably aluminum oxide deposition films. The compositions of the first to third inorganic oxide deposited layers may be identical to or different from each other.

The notation of the inorganic oxide is, for example, represented by MO _X (wherein, M represents an inorganic element and the value of X is different depending on the inorganic element) such as AlO _X , SiO _X etc. Ru. In the present invention, from the viewpoint of interlayer adhesion strength and transparency, when M is aluminum (Al), the value of X is preferably 0.5 to 2.0, and when M is silicon (Si), X The value of is preferably 1 to 2.

  From the viewpoint of ease of handling as a deposition material, it is preferable to provide an aluminum oxide deposition film by physical vapor deposition as the first inorganic oxide deposition layer. The aluminum oxide vapor deposition film formed by physical vapor deposition is excellent in adhesion to the surface of the gas barrier coating film.

  As a physical vapor deposition method, physical vapor deposition methods (Physical Vapor Deposition method, PVD method), such as a vacuum evaporation method, sputtering method, ion plating method, ion cluster beam method, are mentioned, for example.

  Specifically, a vacuum deposition method using aluminum or its oxide as a raw material, heating it to vaporize it, and depositing it on one of the substrate films, for example, using aluminum or its oxide as a raw material Forming an evaporation film using an oxidation reaction vapor deposition method in which oxygen is introduced and oxidized to deposit on one side of a substrate film, and a plasma-assisted oxidation reaction deposition method in which the oxidation reaction is further assisted by plasma Can. In addition, as a heating method of vapor deposition material, it can carry out by resistance heating method, a high frequency induction heating method, an electron beam heating method (EB) etc., for example.

  In the present invention, the film thickness of the aluminum oxide vapor deposition film of the first inorganic oxide vapor deposition layer is preferably 5 to 15 nm, more preferably 7 to 12 nm. If the film thickness of the aluminum oxide vapor deposition film of the first inorganic oxide vapor deposition layer is within the above range, while having suitable gas barrier properties, it becomes easy to prevent the occurrence of cracks due to bending during box making.

  When the second and third inorganic oxide deposited layers are aluminum oxide deposited films, they can be provided in the same manner as the first inorganic oxide deposited layer described above.

  When the second and third inorganic oxide deposited layers are silicon oxide deposited films, it is preferable to provide a silicon oxide deposited film by chemical vapor deposition from the viewpoint of bending resistance and gas barrier properties. As the chemical vapor deposition method, for example, a chemical vapor deposition method (Chemical Vapor Deposition method) such as plasma chemical vapor deposition method, low temperature plasma chemical vapor deposition method, thermal chemical vapor deposition method, photochemical vapor deposition method, etc. CVD method etc. Specifically, a monomer gas for deposition such as an organosilicon compound is used as a raw material on one surface of a substrate film, and an inert gas such as argon gas or helium gas is used as a carrier gas, and an oxygen supply gas The silicon oxide vapor deposition film can be formed using a low temperature plasma chemical vapor deposition method using an oxygen gas or the like and utilizing a low temperature plasma generator or the like. As the low temperature plasma generator, for example, a generator of high frequency plasma, pulse wave plasma, microwave plasma or the like can be used. It is preferable to use a high-frequency plasma generator from the viewpoint of obtaining a stable plasma with high activity.

  In the present invention, as a monomer gas for vapor deposition of an organic silicon compound forming a silicon oxide vapor deposition film, for example, 1,1,3,3-tetramethyldisiloxane, hexamethyldisiloxane, vinyltrimethylsilane, methyltrimethylsilane, Hexamethyldisilane, methylsilane, dimethylsilane, trimethylsilane, diethylsilane, propylsilane, phenylsilane, vinyltriethoxysilane, vinyltrimethoxysilane, tetramethoxysilane, tetraethoxysilane, phenyltrimethoxysilane, methyltriethoxysilane, octa Methyl cyclotetrasiloxane and the like can be used. Among these, it is particularly preferable to use 1,1,3,3-tetramethyldisiloxane or hexamethyldisiloxane as a raw material from the viewpoint of the handleability, the characteristics of the formed continuous film, and the like. In the above, as the inert gas, for example, argon gas, helium gas or the like can be used.

In the present invention, the vapor deposited film of silicon oxide is mainly composed of silicon oxide, but at least one compound of one or more elements of carbon, hydrogen, silicon or oxygen is further chemically bonded You may contain by etc. For example, a compound having a C—H bond, a compound having a Si—H bond, or, when the carbon unit is in the form of graphite, diamond, fullerene, etc., organic silicon compounds as raw materials and derivatives thereof It may be contained by a chemical bond or the like. For example, a hydrocarbon having a CH ₃ site, a hydrosilica such as SiH ₃ silyl and SiH ₂ silylene, and a hydroxyl group derivative such as SiH ₂ OH silanol can be mentioned. In addition to the above, the type, the amount, and the like of the compound contained in the silicon oxide vapor deposition film can be changed by changing the conditions and the like of the vapor deposition process.

  In the present invention, the film thickness of the second and third inorganic oxide deposited layers is preferably 1 to 50 nm, more preferably 5 to 20 nm. When the film thickness of the second and third inorganic oxide deposited layers is within the above range, the barrier film of the present invention can be obtained because it is excellent in the adhesiveness to the heat-sealable resin described below while having suitable gas barrier properties. The laminated material provided is excellent in interlayer adhesion.

(Barrier coat layer)
The barrier coat layer is a layer having gas barrier properties, and is preferably a coating film. Furthermore, the barrier coat layer is preferably a cured film of a hydrolysis product of a metal alkoxide and a water-soluble polymer. The barrier coat layer can be formed, for example, by the following gas barrier coating film. The gas barrier coating film is a coating film which maintains the gas barrier properties under a high temperature and humidity environment, and has a general formula R ¹ _n M (OR ² ) _m (wherein R ¹ and R ^{2 each} have 1 to 1 carbon atoms) 8 represents an organic group, M represents a metal atom, n represents an integer of 0 or more, m represents an integer of 1 or more, and n + m represents a valence of M. A gas barrier composition comprising at least one metal alkoxide and a water-soluble polymer, and further comprising a polycondensation by a sol-gel method in the presence of a sol-gel method catalyst, an acid, water, and an organic solvent Coating film.

In the above general formula R ¹ _n M (OR ² ) _m , R ¹ is an alkyl group having 1 to 8, preferably 1 to 5, more preferably 1 to 4 carbon atoms which may have a branch. For example, methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, sec-butyl group, t-butyl group, n-hexyl group, n-octyl group, etc. It can be mentioned.

In the above general formula R ¹ _n M (OR ² ) _m , R ² is an alkyl group having 1 to 8 carbon atoms, more preferably 1 to 5 and particularly preferably 1 to 4 carbon atoms which may have branching. There are, for example, methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, sec-butyl group and the like. When a plurality of (OR ² ) exist in the same molecule, (OR ² ) may be the same or different.

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

As the alkoxide represented by the above general formula R ¹ _n M (OR ² ) _m , at least one or more of a partial hydrolyzate of the alkoxide and a hydrolysis condensate of the alkoxide can be used, and The partial hydrolyzate is not limited to one in which all of the alkoxy groups are hydrolyzed, but may be one or more hydrolyzed, and may be a mixture thereof, and a condensate of hydrolysis in addition. As the monomer of the partial hydrolysis alkoxide, a dimer or more of a partially hydrolyzed alkoxide, specifically, a 2- to 6-mer may be used.

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

In the present invention, as the alkoxide represented by the above general formula R ¹ _n M (OR ² ) _m , a zirconium alkoxide in which M is Zr can also be suitably used. As preferable zirconium alkoxides, for example, tetramethoxyzirconium Zr (OCH ₃ ) ₄ , tetraethoxyzirconium Zr (OC ₂ H ₅ ) ₄ , tetraipropoxyzirconium Zr (iso-OC ₃ H ₇ ) ₄ , tetra n butoxy zirconium Zr (OC ₄ H ₉ ) _{4 and the} like can be exemplified.

Similarly, the general formula ^R ₁ n M ^(OR ₂₎ as alkoxide represented by _m, M can be suitably used titanium alkoxide is Ti. Suitable titanium alkoxides include, for example, tetramethoxytitanium Ti (OCH ₃ ) ₄ , tetraethoxytitanium Ti (OC ₂ H ₅ ) ₄ , tetraisopropoxytitanium Ti (iso-OC ₃ H ₇ ) ₄ , tetra n-butoxy titanium Ti (OC ₄ H ₉ ) _{4 and the} like can be exemplified.

Moreover, the aluminum alkoxide whose M is Al can also be used suitably as an alkoxide represented by said general formula R _< ¹ _> NM (OR _< ² _> ) _m . As preferable aluminum alkoxides, for example, tetramethoxyaluminum Al (OCH ₃ ) ₄ , tetraethoxyaluminum Al (OC ₂ H ₅ ) ₄ , tetraisopropoxyaluminum Al (iso-OC ₃ H ₇ ) ₄ , tetra n-butoxyaluminum Al (OC ₄ H ₉ ) _{4 and the} like can be exemplified.

  In the present invention, two or more of the alkoxides may be used in combination. For example, when a mixture of alkoxysilane and zirconium alkoxide is used, the toughness, heat resistance and the like of the obtained barrier film can be improved. In addition, when a mixture of alkoxysilane and titanium alkoxide is used, the thermal conductivity of the resulting gas barrier coating film is lowered, and the heat resistance is remarkably improved.

  As the water-soluble polymer used in the present invention, polyvinyl alcohol resins or ethylene / vinyl alcohol copolymers can be used alone, or polyvinyl alcohol resins and ethylene / vinyl alcohol copolymer can be used. Combinations can be used in combination. In the present invention, physical properties such as gas barrier properties, water resistance, weather resistance, and the like can be remarkably improved by using a polyvinyl alcohol resin and / or an ethylene-vinyl alcohol copolymer.

  Generally as a polyvinyl alcohol-type resin, what is obtained by saponifying polyvinyl acetate can be used. As a polyvinyl alcohol-based resin, a partially saponified polyvinyl alcohol-based resin in which several tens of acetic acid groups remain, a completely saponified polyvinyl alcohol in which no acetic acid groups remain, or a modified polyvinyl alcohol-based resin in which OH groups are modified Well, it is not particularly limited.

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

  In addition, a silane coupling agent may be added to the barrier coat layer. For example, a silane coupling material having a reactive group such as an alkoxy group such as a methoxy group or an ethoxy group, an acetoxy group, an amino group or an epoxy group can be used.

  Furthermore, as an organic solvent used in the above-mentioned gas barrier composition, for example, methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butanol and the like can be used. The polyvinyl alcohol resin and / or the ethylene-vinyl alcohol copolymer is preferably handled in a state of being dissolved in a coating solution containing the alkoxide, silane coupling agent, etc., and from among the organic solvents It can be selected appropriately. For example, in the case of using a polyvinyl alcohol resin and an ethylene-vinyl alcohol copolymer in combination, it is preferable to use n-butanol.

  The barrier coat layer can be produced by the following method. First, the above metal alkoxide, if necessary, a silane coupling agent, a water-soluble polymer, a sol-gel method catalyst, an acid, water, an organic solvent and the like are mixed to prepare a gas barrier composition (barrier coating solution).

  Then, the gas barrier composition is applied onto the first inorganic oxide vapor deposition layer. The gas barrier composition may be applied, for example, by one or more applications using a coating method such as roll coating such as gravure roll coater, spray coating, spin coating, dipping, brushing, bar code, or applicator. A coated film having a dry thickness of about 0.01 to 30 μm, preferably about 0.1 to 10 μm can be formed.

  Next, the film coated with the gas barrier composition is heated and dried at 20 ° C. to 200 ° C. and at a temperature below the melting point of the vapor-deposited film, preferably at a temperature in the range of 50 ° C. to 180 ° C. for 10 seconds to 10 minutes . By this, polycondensation is performed, and a barrier coat layer can be formed. In addition, the gas barrier composition is overlaid on the first inorganic oxide vapor deposited layer and coated to form two or more coated films, and the temperature is 20 ° C. to 200 ° C., and not higher than the melting point of the resin base material. The heat drying process may be performed for 10 seconds to 10 minutes at a temperature to form a composite polymer layer in which two or more gas barrier coatings are laminated. According to the above, one or more barrier coat layers can be formed by the gas barrier composition.

<Laminated material>
The laminated material of the present invention comprises an outermost layer, a paper base layer, a first heat fusible resin layer, a barrier layer comprising the barrier film, a second heat fusible resin layer, and an innermost layer. And in this order. Since the laminated material of the present invention has such a layer constitution, it is excellent in interlayer adhesion between the first heat fusible resin layer and the barrier layer and between the barrier layer and the second heat fusible resin layer. Also, the gas barrier properties are excellent. Therefore, the laminate of the present invention can be suitably used as a laminate of various containers and the like that are required to have gas barrier properties and strong adhesiveness, and can be suitably used, for example, as a laminate for paper containers.

  The adhesive strength required for the barrier film and the heat fusible resin in the laminated material for paper containers is 1.5 N / 15 mm or more, preferably 2.0 N / 15 mm or more on the paper substrate side, and the content side In this case, it is 3.0 N / 15 mm or more, preferably 3.5 N / 15 mm or more. If it has this adhesive strength, the laminate of the paper container is punched into a blank plate and stamped by folding for forming creases, peeling of the barrier film and the paper base or resin layer in the laminate, or roll paper It is possible to reduce peeling in steps such as bending, embossing, and cutting in a system for producing a container laminate in-line from a laminated material.

  The layer configuration of the laminated material for paper containers of the present invention will be described with reference to the drawings. The laminated material 20 for paper containers shown in FIG. 2 includes the outermost layer 22, the paper base layer 21, the resin layer 23, the first heat fusible resin layer 24, and the barrier layer barrier film (barrier layer) 10. , The second heat-fusible resin layer 25, the resin layer 26, and the innermost layer 27 in this order. The second inorganic oxide deposited layer 12 of the barrier film 10 is in contact with the first heat fusible resin layer 24, and the third inorganic oxide deposited layer 14 of the barrier film 10 is a second heat fusible resin Alternatively, the second inorganic oxide deposited layer 12 of the barrier film 10 may be in contact with the second heat-fusible resin layer 25 and the third inorganic oxide deposited of the barrier film 10. The layer 14 may be in contact with the second heat-fusible resin layer 24. Hereinafter, each layer which comprises the laminated material for paper containers of this invention is demonstrated.

(The outermost layer)
In the laminated material for paper containers of the present invention, a thermoplastic resin can be used as the outermost layer. Specifically, for example, low density polyethylene, medium density polyethylene, high density polyethylene, linear (linear) low density polyethylene, ethylene-α-olefin copolymer polymerized using a metallocene catalyst, polypropylene, ethylene -Vinyl acetate copolymer, ionomer resin, ethylene-acrylic acid copolymer, ethylene-ethyl acrylate copolymer, ethylene-methacrylic acid copolymer, ethylene-methyl methacrylate copolymer, ethylene-propylene copolymer Acid-modified polyolefin resins obtained by modifying polyolefin resins such as methylpentene polymer, polybutene polymer, polyethylene or polypropylene with unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, itaconic acid, etc. Vinyl acetate resin, (Meth) can be used acrylic resin, resins such as polyvinyl chloride resin.

  In the present invention, the outermost layer is formed by melt-extruding the above-mentioned one or more thermoplastic resins on a paper substrate layer optionally via an anchor coat layer etc. using an extruder or the like. Can. Alternatively, a film or sheet of the resin is produced in advance using one or more of the thermoplastic resins described above, and the produced film or sheet is placed on the paper base layer through an adhesive layer for lamination, etc. It is also possible to form an outermost layer by laminating on a dry laminate.

  In the present invention, the thickness of the outermost layer is preferably about 5 to 200 μm, more preferably about 10 to 100 μm.

(Paper base layer)
In the laminate for paper containers of the present invention, any paper base can be used as the paper base layer depending on the application. In particular, in order to make a box and use it as a liquid paper container, it is necessary to use a paper substrate having a sufficiently high formability, bending resistance, rigidity, stiffness and strength. As such a paper substrate, for example, various sized paper substrates such as strong-sized bleached or unbleached paper substrate or pure white roll paper, kraft paper, paperboard, processed paper, etc., and having a basis weight About 80 to 600 g / m ² or so, preferably about 100 to 450 g / m ² or so can be suitably used.

  In addition, the paper base of the liquid paper container needs to have a certain thickness so as to provide sufficient strength to accommodate the liquid. Since the barrier film for paper containers of the present invention can be adhered to such a thick paper substrate with high interlayer adhesion strength, the paper container made of this can be used for various packaging applications for containing liquids. Can be suitably used. Moreover, it can be set as the form which can be self-supporting, such as a cube.

  As a method of laminating the paper base layer on the first heat-fusible resin layer, lamination may be carried out by extruding the above-mentioned one or more thermoplastic resins, or an adhesive or the like may be used. Dry lamination.

(Heat fusible resin layer)
In the laminated material for paper containers of the present invention, an ethylene-based polymer having a carboxyl group or an acid anhydride group in the molecule is suitably used as the heat-fusible resin constituting the heat-fusible resin layer. The ethylene-based polymer can exhibit excellent interlayer adhesion when in contact with the second and third inorganic oxide deposited layers of the barrier film.

  As said ethylene-based polymer, the copolymer of ethylene and unsaturated carboxylic acid or its anhydride is mentioned. The unsaturated carboxylic acid or an anhydride thereof is a compound having at least one carboxyl group or acid anhydride group in the molecule, and specifically, acrylic acid, methacrylic acid, maleic acid, maleic anhydride And itaconic acid, itaconic anhydride, fumaric acid, crotonic acid and the like. A copolymer of ethylene and acrylic acid or methacrylic acid is particularly preferably used in order to improve the adhesion to the vapor-deposited film of the inorganic oxide.

  In the above-mentioned ethylene-based copolymer, the ratio between ethylene and unsaturated carboxylic acid or its anhydride, the melt flow rate (MFR), etc. are appropriately determined by those skilled in the art according to the properties of the paper substrate to be used, etc. can do. In general, in order to enhance the adhesion between the heat sealable resin layer and the barrier film, it is preferable that the proportion of unsaturated carboxylic acid or its anhydride in the ethylene copolymer is high. In the present invention, the percentage of unsaturated carboxylic acid or anhydride thereof in the ethylene copolymer is 3% to 9% by adhering the heat-fusible resin layer through the inorganic oxide deposition layer on the barrier film. Sufficient adhesive strength can be achieved even at a rate as low as%.

  In the present invention, the thickness of the heat-fusible resin layer is preferably about 1 to 50 μm, more preferably about 3 to 20 μm, from the viewpoint of film forming property and adhesiveness.

(Innermost layer)
In the laminate for paper containers of the present invention, as the innermost layer, a resin having heat sealability can be used. Specifically, the same resin as the outermost layer described above can be used.

  The innermost layer can be provided on the surface of the second heat fusible resin layer side by melt-extruding this thermoplastic resin using an extruder or the like using the above one or more thermoplastic resins. Alternatively, a film or sheet of the resin may be produced in advance using the film or sheet of one or more of the thermoplastic resins described above, and the produced film or sheet may be used as an adhesive layer for laminating, etc. Dry lamination may be performed on the surface on the side of the second heat-fusible resin layer. If desired, the surface to be laminated may be subjected to various surface treatments such as application of an anchor coating agent in advance. In addition, one or more resin layers may be provided between the innermost layer and the second heat-heat-fusible resin layer by extruding the one or more thermoplastic resins.

  In order to form the innermost layer of the present invention, low density polyethylene can be suitably used, and particularly preferably using linear (linear) low density polyethylene polymerized using a metallocene catalyst it can. Since these resins exhibit low-temperature sealing properties, excessive heat load can be applied to the vapor-deposited film of the inner layer during lamination or box-making to prevent the occurrence of cracks and the like. Moreover, it has the advantage that generation | occurrence | production of a pinhole can be prevented and a sealing defect, a liquid leak, etc. can be avoided. Other resins can be blended with the above resins to obtain desired properties. In addition, various additives such as antioxidants, ultraviolet light absorbers, antistatic agents, anti blocking agents, lubricants (fatty acid amides, etc.), flame retardants, inorganic or organic fillers, dyes, pigments, etc. are optionally added. Can be used.

  In the present invention, the film thickness of the innermost layer is preferably about 10 μm to 300 μm, more preferably about 20 μm to 100 μm, in order to prevent seal failure.

<Paper container>
The paper container of the present invention is produced by box-forming the above-mentioned laminate for paper container, and can be suitably used particularly as a liquid paper container.

  The paper container may be of any type, such as, for example, a brick type, a flat type or a gobel top type. Further, the shape thereof may be any of a square container, a cylindrical paper can such as a round shape, and the like. The paper container of the present invention can be filled and packaged with various articles such as various food and drink, chemicals such as adhesives and adhesives, and general goods such as cosmetics and medicines. In particular, it is useful, for example, as a liquid paper container for filling and packaging various liquid foods and beverages such as juices such as liquor and juice, mineral water, soy sauce, sauces and soups, or various liquid foods and drinks such as curries, stews and soups. It is a thing.

  The paper container has a volume of 200 mL and preferably has an oxygen permeability of not more than 0.15 cc / pkg · day, more preferably 0.1 cc / pkg · day, measured under an environment of temperature 23 ° C. and humidity 50 RH%. Or less, more preferably 0.03 cc / pkg · day or less. If the oxygen permeability of the paper container satisfies the above numerical range, the adverse effect on the contents of the paper container can be suppressed.

  The paper container has a volume of 200 mL and is measured in a 40 ° C. environment. The water vapor transmission rate from the inside of the container to the outside of the container is preferably 0.3 g / pkg · day or less, more preferably 0.1 g / pkg. It is not more than day, and more preferably not more than 0.05 g / pkg · day. If the water vapor permeability of the paper container satisfies the above-mentioned numerical range, it has suitable water vapor barrier properties, so that the adverse effect on the contents of the paper container can be suppressed.

  EXAMPLES Hereinafter, the present invention will be more specifically described by way of examples, but the present invention is not limited to the following examples.

<Production of barrier film and laminated material>
Example 1
A 12 μm thick biaxially stretched polyethylene terephthalate (PET) film was prepared as a base film. The plasma supply nozzle under the following plasma conditions in the pretreatment section using the continuous deposition film forming apparatus in which the pretreatment section in which the plasma pretreatment apparatus is disposed on the surface forming the deposition layer of the PET film is separated from the deposition section. The plasma is introduced from above and subjected to plasma pretreatment at a transfer speed of 600 m / min, and then, in the continuously transferred film forming section, on the plasma treated surface, reactive resistance heating as heating means under the following conditions. A 9.4 nm-thick aluminum oxide vapor deposition film (first inorganic oxide vapor deposition layer) was formed.
(Plasma pretreatment conditions)
・ Plasma strength: 150 W · sec / m ²
Plasma forming gas: argon 1200 (sccm), oxygen 3000 (sccm)
Magnetic forming means: permanent magnet of 1000 gauss Applied voltage between pretreatment drum and plasma supply nozzle: 340 V
-Degree of vacuum in the pretreatment compartment: 3.8 Pa
(Aluminum oxide film formation conditions)
-Degree of vacuum: 8.1 × 10 ^-2 Pa

Moreover, according to the composition shown in Table 1, the hydrolysis liquid of the composition B prepared beforehand was added to the liquid mixture of the prepared composition A, and it stirred, and obtained the colorless and transparent gas barrier composition.

  Next, the gas barrier composition prepared above was coated on the aluminum oxide vapor deposition film of the PET film by a direct gravure method. Thereafter, heat treatment was carried out at 140 ° C. for 60 seconds to form a gas barrier coating film having a thickness of 0.3 μm (dry state).

  Next, using the continuous vapor deposition film deposition apparatus in which the pretreatment zone in which the plasma pretreatment apparatus is disposed and the deposition zone are separated on the gas barrier coating film, a plasma supply nozzle under the following plasma conditions in the pretreatment zone The plasma is introduced from the substrate, plasma pretreatment is performed at a transfer speed of 600 m / min, and then, in the continuously transferred film forming section, thickness is applied by reactive resistance heating as a heating means of vacuum deposition on the plasma treated surface. An aluminum oxide vapor deposition film (second inorganic oxide vapor deposition layer) of 8 nm was formed.

  Subsequently, plasma is supplied under the following plasma conditions in the pretreatment zone using the continuous deposition film deposition system in which the pretreatment zone where the plasma pretreatment apparatus is disposed and the deposition zone are separated on the other surface of the PET film. Plasma is introduced from a nozzle, plasma pretreatment is performed at a transfer speed of 600 m / min, and then, in a continuously transferred film forming section, thickness is increased by reactive resistance heating as a heating means of a vacuum evaporation method on a plasma treated surface. An aluminum oxide vapor deposition film (third inorganic oxide vapor deposition layer) having a thickness of 8 nm is formed, and the barrier film 1 (layer configuration: “second inorganic oxide vapor deposition layer / barrier coating layer / first inorganic oxide vapor deposition Layer / substrate film / third inorganic oxide deposited layer ") was obtained.

  An ethylene / methacrylic acid copolymer (EMAA, manufactured by Du Pont-Mitsui Polychemicals Co., Ltd .: Nucrel N-0 908 C) (on the other hand, deposited on the one deposited aluminum oxide film (the second deposited inorganic oxide layer) of the barrier film 1). The extrusion temperature: 290 ° C., and the thickness of the extruded film: 15 μm were melt-extruded to form a first heat-fusible resin layer. Further, on the other aluminum oxide vapor deposition film (third inorganic oxide vapor deposition layer) of the barrier film 1, an ethylene / methacrylic acid copolymer (EMAA, manufactured by Mitsui DuPont Polychemical Co., Ltd .: nucrel N-0 908 C) (extrusion) Temperature: 290 ° C., extruded film thickness: 15 μm) was melt-extruded to form a second heat-fusible resin layer, to obtain a laminated intermediate.

  Subsequently, the second heat-fusible resin layer surface of the laminated intermediate and the ethylene-α-olefin copolymer film (m-PEF) (thickness 15 μm) to be the innermost layer are formed by sandwich laminating method. Lamination was carried out through low density polyethylene (extrusion temperature: 300 ° C., extrusion thickness: 15 μm).

  After corona discharge treatment is applied to one side of a paper substrate (thickness 200 g / m), low density polyethylene resin (extrusion temperature: 300 ° C., thickness of extruded film: 15 μm) is applied to the corona discharge treated side. It melt-extruded and formed the outermost layer. Subsequently, the first heat fusible resin layer side of the above laminated intermediate and the other side of the paper substrate are laminated by low density polyethylene (extruded film thickness: 15 μm) by a sandwich laminating method. , Laminated material 1 (layer configuration: "the outermost layer / paper base layer / resin layer / first heat sealable resin layer / barrier film 1 (second inorganic oxide deposited layer / barrier coat layer / first Inorganic oxide deposited layer / substrate film / third inorganic oxide deposited layer) / second heat-fusible resin layer / resin layer / innermost layer ") was obtained.

Example 2
The barrier film 2 was formed in the same manner as in Example 1 except that the thickness of the aluminum oxide vapor deposition film (first inorganic oxide vapor deposition layer) formed on the substrate film was changed from 9.4 nm to 11.8 nm. Obtained.

  Subsequently, a laminated material 2 was obtained in the same manner as in Example 1 except that the barrier film 1 was changed to the barrier film 2.

[Example 3]
The same as Example 1 except that after the aluminum oxide vapor deposition film (third inorganic oxide vapor deposition layer) of the barrier film 1 was subjected to corona treatment (2 kW) and then the second heat-fusible resin layer was formed. The laminated material 3 was obtained.

Example 4
A first heat-fusible resin layer was formed on the third inorganic oxide vapor-deposited layer of the barrier film 1 and a second heat-fusible resin layer was formed on the second inorganic oxide vapor-deposited layer Laminated material 4 (layer constitution: “the outermost layer / paper base layer / resin layer / first heat-fusible resin layer / barrier film 1 (third inorganic oxide) in the same manner as in Example 1 except for Deposited layer / base film / first inorganic oxide deposited layer / barrier coat layer / second inorganic oxide deposited layer) / second heat fusible resin layer / resin layer / innermost layer ") .

Comparative Example 1
A barrier film 3 was obtained in the same manner as in Example 1 except that the third inorganic oxide vapor deposition layer was not formed.

  Subsequently, a laminated material 5 was obtained in the same manner as Example 1, except that the barrier film 1 was changed to the barrier film 3.

Comparative Example 2
A barrier film 4 was obtained in the same manner as in Example 1 except that the second inorganic oxide deposited layer and the third inorganic oxide deposited layer were not formed.

  Subsequently, a laminated material 6 was obtained in the same manner as Example 1, except that the barrier film 1 was changed to the barrier film 4.

Comparative Example 3
Except that the second heat-fusible resin layer is formed after corona treatment (2 kW) is applied on the other surface of the PET film of the above-mentioned barrier film 4 (the surface on which the third inorganic oxide deposited layer is not provided). A laminated material 7 was obtained in the same manner as in Comparative Example 2.

Comparative Example 4
Except that the second heat-fusible resin layer is formed after corona treatment (6 kW) is applied on the other surface (surface not provided with the third inorganic oxide deposited layer) of the PET film of the barrier film 4 A laminated material 8 was obtained in the same manner as in Comparative Example 2.

<Performance evaluation of barrier film and laminated material>
The following measurement was performed about the barrier film and laminated material which were manufactured by said Example and comparative example.

(Measurement of interlayer adhesion strength)
Using a tensile tester (Tensilon Universal Tester RTC 1310A, manufactured by ORIENTEC Co., Ltd.), the laminated intermediate provided with the first and second heat-fusible resin layers on both sides in the above Examples and Comparative Examples. A 90 ° peel test was conducted at a speed of 50 mm / min to measure the peel strength (N / 15 mm) at the interface between the first heat-fusible resin layer and the barrier film. Moreover, similarly, the peel strength (N / 15 mm) of the interface between the barrier film and the second heat-fusible resin layer was measured. The measurement results are shown in Table 2.

(Measurement of oxygen permeability)
The barrier films manufactured in the above Examples and Comparative Examples were measured according to JIS K 7126 using a measuring machine (model name: OXTRAN) manufactured by MOCON Co., Ltd. under the conditions of temperature 23 ° C. and humidity 90% RH. In accordance with the above, oxygen permeability (cc / m ² · day) was measured. The measurement results are shown in Table 2.

(Measurement of water vapor permeability)
The water vapor transmission rate was measured according to JIS K 7129 using a measuring machine (model name: OXTRAN) manufactured by MOCON (USA) for the barrier films manufactured in the above Examples and Comparative Examples. Each of the barrier films produced in Examples and Comparative Examples was 1.0 g / m ² · day or less.

  The laminated materials produced in the above Examples and Comparative Examples were cast to produce a 200 mL size brick-type paper container. About the obtained paper container, the sealing jig connected to the measuring machine (model name: OXTRAN) made in the United States of America (MOCON) in the environment of temperature 23 ° C and humidity 50% RH is attached, and it is in a paper container Incoming oxygen permeability (cc / pkg · day) was measured. The measurement results are shown in Table 2.

10 barrier film 11 base film 12 second inorganic oxide deposited layer 13 first inorganic oxide deposited layer 14 third inorganic oxide deposited layer 15 barrier coat layer 20 laminated material for paper container 21 paper base layer 22 Outermost layer 23 resin layer 24 first heat fusible resin layer 25 second heat fusible resin layer 26 resin layer 27 innermost layer

Claims (10)

A barrier film comprising a second inorganic oxide deposited layer, a barrier coat layer, a first inorganic oxide deposited layer, a base film, and a third inorganic oxide deposited layer in this order. ,
The barrier coat layer is a cured film of a hydrolysis product of a metal alkoxide and a water-soluble polymer,
A barrier film, wherein the first inorganic oxide deposited layer is an aluminum oxide deposited film.   The barrier film according to claim 1, wherein the aluminum oxide deposited film of the first inorganic oxide deposited layer has a thickness of 5 to 15 nm.   The barrier film according to claim 1, wherein the second inorganic oxide deposited layer is an aluminum oxide deposited film.   The barrier film according to any one of claims 1 to 3, wherein the third inorganic oxide deposited layer is an aluminum oxide deposited film.   The barrier film according to any one of claims 1 to 4, which is for a paper container. Paper container laminate comprising an outermost layer, a paper base layer, a first heat-fusible resin layer, a barrier layer, a second heat-fusible resin layer, and an innermost layer in this order Materials,
The laminated material for paper containers in which the said barrier layer consists of a barrier film as described in any one of Claims 1-5.   The laminated material for paper containers of Claim 6 which is an ethylene-type polymer which has a carboxyl group or an acid anhydride group in a molecule | numerator in the heat-fusion resin which comprises the said heat-fusion resin layer. The second inorganic oxide deposited layer of the barrier film is in contact with the first thermally fusible resin layer,
The laminated material for paper containers of Claim 6 or 7 in which the 3rd inorganic oxide vapor deposition layer of the said barrier film is in contact with the said 2nd heat fusible resin layer.   A resin layer is further provided between the paper base layer and the first heat fusible resin layer and / or between the second heat fusible resin layer and the innermost layer. The laminated material for paper containers as described in any one of -8.   The paper container formed by box-producing the laminated material for paper containers as described in any one of Claims 6-9.

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