JP2014141014A - Barrier film for a paper container, laminate material for a paper container consisting of the same, and paper liquid container - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a barrier film for a paper container exhibiting a high gas barrier capacity and, when laminated on a paper substrate via a heat-fusible resin, an excellent interlayer adhesive strength.SOLUTION: In the provided barrier film for a paper container, a silicon oxide deposition film a formed by the chemical vapor deposition method, a gas-barrier coating film b, and an aluminum oxide deposition film c formed by the physical vapor growth method are laminated in proper order on one surface of a substrate film d, whereas the aluminum oxide deposition film c is laminated so as to constitute the outermost surface of the barrier film.

Description

  The present invention relates to a paper container barrier film, and a paper container laminate and a liquid paper container comprising the same. More specifically, the present invention relates to a barrier film for paper containers that is excellent in gas barrier properties such as oxygen barrier properties and water vapor barrier properties, and exhibits excellent interlayer adhesion strength when laminated with a paper substrate, and the paper containers. The present invention relates to a laminated material for a paper container comprising a barrier film for use and a paper base material, and a liquid paper container comprising the same.

Conventionally, liquid paper containers of various forms have been developed and proposed for filling and packaging liquids such as alcoholic beverages, juices, mineral water, liquid seasonings and the like, and chemical products.
Examples of such a liquid paper container include those obtained by boxing a paper container laminate having an outermost layer, a paper base layer, an adhesive layer, a barrier layer, and an innermost layer. Here, as the barrier layer, for example, a barrier film in which a vapor deposition film of an inorganic oxide is provided on one surface of a base film such as a resin film is used (Patent Document 1).

However, since the vapor-deposited film of inorganic oxide is an inflexible thin film, cracks and the like are easily generated by heat and pressure applied from the outside during processing such as lamination or box making, and gas barrier properties are impaired. There is a problem.
On the other hand, it is known to prevent the occurrence of cracks and the like by providing a coating layer that protects the deposited film on the deposited film.

  As such a coating layer, a gas barrier composition composed of a metal alkoxide and polyvinyl alcohol can be used to not only protect the deposited film but also to further improve the gas barrier property by being superimposed on the deposited film. Is coated on a vapor deposition film, and a coating film is formed by a sol-gel method to form a gas barrier coating film.

  On the other hand, the paper base used in the paper container laminate is required to have a certain thickness in order to obtain the self-supporting property and strength of the container. However, when a paper base having a sufficient thickness is laminated with another base via an adhesive layer, sufficient interlaminar adhesive strength cannot be obtained, and delamination tends to occur.

In particular, when a paper substrate is laminated with the gas barrier coating film of the barrier film, there is a problem that sufficient interlayer adhesive strength cannot be obtained, and thereby sufficient gas barrier properties are not exhibited.
In order to solve these problems, it is known that a primer agent is applied to the surface of the gas barrier coating film in advance, followed by further ozone treatment, and then laminated with a paper substrate.

  However, the primer agent coating step and the ozone treatment step have a problem that much labor, time and cost are required. Moreover, there is a problem that sufficient interlayer adhesion strength cannot be obtained even after these steps.

JP 2002-154524 A

  The present invention overcomes the above problems, exhibits a high gas barrier property, and exhibits a superior interlayer adhesion strength when laminated with a paper base material via a heat-fusible resin, and a barrier film for a paper container, and It is an object of the present invention to provide a paper container laminate material obtained by laminating a paper container barrier film and a paper base material via a heat-fusible resin, and a liquid paper container comprising the same.

  As a result of various studies, the present inventor has surprisingly found that heat deposition is achieved by providing an aluminum oxide vapor deposition film by a physical vapor deposition method on a gas barrier coating film made of a gas barrier composition containing an alkoxide. When laminating with a paper substrate via a functional resin, it was found that high interlayer adhesion strength was obtained, and the present invention was achieved.

More specifically, the present invention is characterized by the following points.
1. (A) a silicon oxide vapor deposition film formed by chemical vapor deposition, (b) a general formula R ¹ _n M (OR ² ) _m (where R ¹ , R ² represents an organic group having 1 to 8 carbon atoms, M represents a metal atom, n represents an integer of 0 or more, m represents an integer of 1 or more, and n + m represents the valence of M. Gas barrier properties by a gas barrier composition obtained by polycondensation by a sol-gel method, containing at least one alkoxide represented by (1)) and a polyvinyl alcohol resin and / or an ethylene / vinyl alcohol copolymer. A paper container in which a coating film and (c) an aluminum oxide vapor deposition film formed by physical vapor deposition are laminated in this order, and the (c) aluminum oxide vapor deposition film is laminated on the outermost surface of the barrier film. Barrier film.
2. At least the outermost layer, the paper base material layer, the heat-fusible resin layer, The barrier layer composed of the barrier film for paper containers and the innermost layer are sequentially laminated, and the surface of the aluminum oxide vapor deposition film of the barrier film for paper containers faces the heat-fusible resin layer. And a laminated material for paper containers laminated so as to be in direct contact with the heat-fusible resin layer.
3. 2. The heat-sealable resin constituting the heat-sealable resin layer is an ethylene polymer having a carboxyl group or an acid anhydride group in the molecule. The laminated material for paper containers as described in 2.
4). 2. Or 3. A liquid paper container, which is formed by boxing the laminated material described in 1.

  The barrier film for paper containers of the present invention exhibits excellent interlayer adhesion strength when laminated with a paper base material via a heat-fusible resin. In addition to providing an aluminum oxide vapor deposition film by physical vapor deposition, various surface treatment steps for increasing the interlayer adhesion strength, such as a primer agent coating step and an ozone treatment step, are unnecessary.

  In addition, as a heat-fusible resin, an ethylene polymer having a carboxyl group or an acid anhydride group in the molecule, such as a copolymer of ethylene and an unsaturated carboxylic acid, such as an ethylene / methacrylic acid copolymer (EMAA). Etc., extremely high interlayer adhesion strength can be obtained.

  Further, in the barrier film for paper containers of the present invention, the aluminum oxide vapor-deposited film not only has excellent adhesion to the heat-fusible resin, but itself has gas barrier properties, particularly water vapor barrier properties, A certain gas barrier property is maintained after lamination with a paper base material and after box making. Therefore, the liquid paper container comprising the barrier film for paper container of the present invention has excellent quality retention, and dislikes the permeation of oxygen and water vapor, or dislikes the evaporation of the contents, such as foods, beverages, pharmaceuticals, etc. It can be suitably used for packaging of goods.

  Furthermore, the paper base material of the liquid paper container needs to have a certain thickness so as to give sufficient strength to accommodate the liquid. Since the barrier film for paper containers of the present invention can be bonded to such a thick paper base material with high interlayer adhesive strength, the paper container comprising this can be used in various packaging applications for containing liquids. Can be suitably used. Moreover, it can be set as the form which can become independent, such as a cube.

It is a schematic sectional drawing which shows the example about the layer structure of the barrier film for paper containers of this invention. It is a schematic sectional drawing which shows the example about the layer structure of the laminated material for paper containers of this invention. It is a schematic block diagram which shows an example of a low temperature plasma chemical vapor deposition apparatus. It is a schematic block diagram which shows an example of a winding-type vacuum deposition apparatus.

The above-described present invention will be described in more detail below.
Hereinafter, the resin names used in the present invention are those commonly used in the industry.
<I> Layer Configuration of Barrier Film and Laminate As shown in FIG. 1, the barrier film for paper containers of the present invention comprises a base film (d), a silicon oxide vapor deposition film (a), and a gas barrier coating film (b). And an aluminum oxide vapor deposition film (c) in this order. Here, the aluminum oxide vapor deposition film (c) always forms the outermost surface of the barrier film. Before laminating the silicon oxide vapor deposition film (a) on the base film (d), the laminated surface of the base film (d) may be subjected to various surface treatments. Similarly, before the gas barrier coating film (b) is laminated on the silicon oxide vapor deposition film (a), the laminated surface of the silicon oxide vapor deposition film (a) may be subjected to various surface treatments. . Furthermore, before laminating the aluminum oxide vapor deposition film (c), the laminated surface of the gas barrier coating film (b) may be subjected to surface treatment such as plasma treatment.

  Moreover, as shown in FIG. 2, the laminated material for paper containers of the present invention comprises at least an outermost layer (1), a paper base layer (2), a heat-fusible resin layer (3), and the paper of the present invention. The layer structure which has the barrier layer (4) which consists of a barrier film for containers, and an innermost layer (5) in this order is fundamental. Here, it laminates | stacks so that the surface of the aluminum oxide vapor deposition film (c) of the barrier film which comprises a barrier layer (4) may oppose a heat-fusible resin layer (3), and may contact this directly.

  In the laminated material for paper containers of the present invention, an aluminum oxide vapor deposition film (c) is formed on the gas barrier coating film (b), and the aluminum oxide vapor deposition film and the paper base material are combined with a heat-fusible resin layer ( It is characterized by being laminated through 3).

  Although not shown, for example, between the outermost layer (1) and the paper base material layer (2), between the paper base material layer (2) and the heat-fusible resin layer (3), and the barrier layer (4). A printing layer and various surface treatment layers such as an anchor coating agent layer may be provided between the innermost layer 5 and the innermost layer 5.

<2> Base film The base film used in the barrier film for paper containers of the present invention has excellent chemical or physical strength, can withstand the conditions for forming a silicon oxide deposited film, and the like. A resin film that can be satisfactorily maintained without impairing the film properties can be used. 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 resins such as various nylons. Various resin films such as polyurethane resin, acetal resin, and cellulose resin can be used. In the present invention, among the above resin films, it is particularly preferable to use a polyester resin, polyolefin resin, or polyamide resin film. As the base film, any of an unstretched film of the resin and a resin film stretched in a uniaxial direction or a biaxial direction can be used.

  In the present invention, as the above-mentioned various resin films, for example, one or more of the above-mentioned various resins are used and manufactured by extrusion method, cast molding method, T-die method, cutting method, inflation method, etc. Using the film forming method, the above-mentioned various resins can be formed into a single film, or the two or more types of various resins can be used to form a multi-layer coextrusion film. Resin is used, and various resin films are manufactured by mixing and forming a film before forming a film. If necessary, for example, a tenter method or a tubular method is used. Various types of resin films that are stretched in a uniaxial or biaxial direction can be used.

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.
It should be noted that one or more of the above-mentioned various resins are used, and in forming the film, for example, film processability, heat resistance, weather resistance, mechanical properties, dimensional stability, antioxidant properties, slipperiness In addition, various plastic compounding agents and additives can be added for the purpose of improving and modifying mold release properties, flame retardancy, antifungal properties, electrical properties, strength, etc. A very small amount to several tens of percent can be arbitrarily added depending on the purpose.

  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. In this case, a modifying resin or the like can also be used.

  In this invention, although a silicon oxide vapor deposition film is formed in one surface of said base film, you may surface-treat a base film previously. Thereby, the adhesiveness with the silicon oxide vapor deposition film can be improved. Similarly, a surface treatment can be performed on the vapor deposition layer to improve the adhesion with the gas barrier coating film.

  Examples of such surface treatment include pretreatment such as corona discharge treatment, ozone treatment, low temperature plasma treatment using oxygen gas or nitrogen gas, glow discharge treatment, oxidation treatment using chemicals and the like.

  In addition, a primer coating agent, an undercoat agent, a vapor deposition anchor coating agent, or the like can be optionally applied for surface treatment. Examples of the coating agent include polyester resins, polyamide resins, polyurethane resins, epoxy resins, phenol resins, (meth) acrylic resins, polyvinyl acetate resins, polyolefins such as polyethylene or polypropylene. A resin composition containing a resin or a copolymer or modified resin thereof, a cellulose resin, or the like as a 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 in which surface modification is performed using a plasma gas generated by ionizing a gas by arc discharge. In addition to the above, an inorganic gas such as oxygen gas, nitrogen gas, argon gas, helium gas can be used as the plasma gas. For example, immediately before forming a silicon oxide deposition film by chemical vapor deposition, in-line plasma treatment removes moisture, dust, etc. on the surface of the substrate film, and smoothes and activates the surface. It is possible to perform surface treatment. In addition, plasma treatment can be performed after vapor deposition to improve adhesion. In the present invention, as the plasma treatment, it is preferable to perform the plasma discharge treatment in consideration of the plasma output, the type of plasma gas, the supply amount of the plasma gas, the treatment time, and other conditions. In addition, as a method for generating plasma, devices such as direct current glow discharge, high frequency discharge, and microwave discharge can be used. In addition, plasma treatment can be performed by an atmospheric pressure plasma treatment method.

<3> Silicon oxide vapor deposition film In the barrier film for paper containers of the present invention, the vapor deposition film provided on the base film is a vapor deposition of an inorganic oxide or an inorganic nitride by various chemical vapor deposition methods or physical vapor deposition methods. In particular, it is preferable to provide a silicon oxide vapor deposition film by a chemical vapor deposition method from the viewpoint of bending resistance.

  The silicon oxide vapor-deposited film can be manufactured by forming a single layer film consisting of one layer of silicon oxide vapor-deposited film or a multilayer film consisting of two or more layers by chemical vapor deposition.

  A silicon oxide vapor deposition film formed by a chemical vapor deposition method exhibits high gas barrier properties, excellent flexibility, and resistance to elongation. Further, by superposing the gas barrier coating film of the present invention on the surface, it effectively works with this and exhibits higher gas barrier properties, flexibility and bending resistance. Therefore, even when laminated with a paper substrate having a certain thickness and processed into a liquid paper container or the like, cracks are hardly generated, and excellent gas barrier properties can be exhibited over a long period of time.

  Examples of the chemical vapor deposition method include chemical vapor deposition methods such as plasma chemical vapor deposition method, low temperature plasma chemical vapor deposition method, thermal chemical vapor deposition method, and photochemical vapor deposition method (Chemical Vapor Deposition method), CVD method). Specifically, a vapor deposition monomer gas such as an organosilicon compound is used as a raw material on one surface of a base film, and an inert gas such as argon gas or helium gas is used as a carrier gas. As described above, a silicon oxide vapor deposition film can be formed using a low temperature plasma chemical vapor deposition method using oxygen gas or the like and using a low temperature plasma generator or the like.

In the above, as a low temperature plasma generator, generators, such as high frequency plasma, pulse wave plasma, and microwave plasma, can be used, for example. In view of obtaining highly active and stable plasma, it is preferable to use a high-frequency plasma generator.
An example of a method for forming a silicon oxide vapor deposition film by the low temperature plasma chemical vapor deposition method will be described with reference to FIG. 3 which is a schematic configuration diagram of a low temperature plasma chemical vapor deposition apparatus.

  In the present invention, the base film 11 is unwound from the unwinding roll 23 disposed in the vacuum chamber 22 of the plasma chemical vapor deposition apparatus 21, and the base film 11 is further passed through the auxiliary roll 24 at a predetermined speed. Then, it is conveyed on the circumferential surface of the cooling / electrode drum 25. On the other hand, a vapor deposition monomer gas such as oxygen gas, inert gas, or organosilicon compound is supplied from the gas supply devices 26 and 27 and the raw material volatilization supply device 28 to prepare a mixed gas composition for vapor deposition. The material is introduced into the vacuum chamber 22 through the raw material supply nozzle 29. The mixed gas composition for vapor deposition is supplied onto the substrate film 11 transported on the circumferential surface of the cooling / electrode drum 25, and plasma is generated and irradiated by glow discharge plasma 30 to form a silicon oxide vapor deposition film. Turn into. Next, if the base film 11 on which the silicon oxide vapor deposition film is formed is wound around the take-up roll 34 via the auxiliary roll 33, a silicon oxide vapor deposition film can be formed by plasma chemical vapor deposition. A predetermined power is applied to the cooling / electrode drum 25 from a power supply 31 disposed outside the vacuum chamber 22, and a magnet 32 is disposed in the vicinity of the cooling / electrode drum 25 to promote plasma generation. Has been. Since a predetermined voltage is applied from the power source to the cooling / electrode drum in this way, glow discharge plasma is generated in the vicinity of the opening of the raw material supply nozzle in the vacuum chamber and the cooling / electrode drum. The glow discharge plasma is derived from one or more gas components in the mixed gas. When the base film is conveyed at a constant speed in this state, the glow discharge plasma causes the cooling / electrode drum surface to be A silicon oxide vapor deposition film can be formed on the base film. In FIG. 3, reference numeral 35 denotes a vacuum pump.

The raw material volatilization supply device volatilizes the organic silicon compound as the raw material, mixes it with oxygen gas, inert gas, etc. supplied from the gas supply device, and introduces this mixed gas into the vacuum chamber through the raw material supply nozzle. . At this time, the content (slm) of the organosilicon compound in the mixed gas is 1 to 40%, the oxygen gas content is 10 to 70%, and the inert gas content is 10 to 60%. For example, the mixing ratio of organosilicon compound: oxygen gas: inert gas can be about 1: 6: 5 to 1:17:14. The silicon oxide vapor-deposited film thus obtained is formed on the base film in the form of a thin film in the form of SiO _x while oxidizing the plasma-formed source gas with oxygen gas. The deposited film is a continuous layer that is dense, has few gaps, and is highly flexible. Therefore, the barrier property of the deposited silicon oxide film is much higher than that of the deposited silicon oxide film formed by a conventional vacuum deposition method or the like. A sufficient barrier property can be obtained with a high and thin film thickness. In addition, the surface of the base film is cleaned by SiO _X plasma, and polar groups, free radicals, etc. are generated on the surface of the base film. Is expensive. Furthermore, the degree of vacuum at the time of forming a continuous film of silicon oxide is 1 × 10 ⁻¹ to 1 × 10 ⁻⁴ Torr, preferably 1 × 10 ⁻¹ to 1 × 10 ⁻² Torr. Since the vacuum degree when forming a silicon oxide vapor deposition film by the vapor deposition method is lower than 1 × 10 ⁻⁴ to 1 × 10 ⁻⁵ Torr, the vacuum state is set when the base film is replaced Time can be shortened, the degree of vacuum is easily stabilized, and the film forming process is also stabilized.

In the present invention, a vapor deposition film of silicon oxide formed using a vapor deposition monomer gas such as an organosilicon compound chemically reacts with a vapor deposition monomer gas such as an organosilicon compound and oxygen gas, and the reaction product is It is closely bonded to one surface of a base film to form a dense thin film having high flexibility, and is usually represented by the general formula SiO _x (where X represents a number from 0 to 2). It is a continuous thin film mainly composed of silicon oxide. The silicon oxide vapor-deposited film is a silicon oxide vapor-deposited film represented by the general formula SiO _x (where X represents the number from 1.3 to 1.9) in terms of transparency and barrier properties. A thin film mainly composed of is preferable. The value of X varies depending on the molar ratio of vapor deposition monomer gas and oxygen gas, plasma energy, etc. Generally, the gas permeability decreases as the value of X decreases, but the film itself is yellow. The transparency becomes worse.

In the present invention, the silicon oxide vapor-deposited film is mainly composed of silicon oxide, and further contains at least one compound of carbon, hydrogen, silicon or oxygen, or a compound composed of two or more elements by chemical bonding or the like. It consists of a vapor deposition film. For example, when a compound having a C—H bond, a compound having a Si—H bond, or a carbon unit is in the form of graphite, diamond, fullerene, or the like, the raw material organosilicon compound or a derivative thereof is further added. It may be contained by a chemical bond or the like. Examples thereof include hydrocarbons having a CH ₃ site, hydrosilica such as SiH ₃ silyl and SiH ₂ silylene, and hydroxyl derivatives such as SiH ₂ OH silanol. In addition to the above, the type, amount, etc. of the compound contained in the silicon oxide vapor deposition film can be changed by changing the conditions of the vapor deposition process. At this time, the content of the compound in the silicon oxide vapor-deposited film is 0.1 to 50% by mass, preferably 5 to 20% by mass. When the content is less than 0.1% by mass, the impact resistance, spreadability, flexibility, etc. of the silicon oxide vapor-deposited film become insufficient, and scratches, cracks, etc. are likely to occur due to bending, and a high barrier property. On the other hand, it may be difficult to maintain stably. On the other hand, if it exceeds 50% by mass, the barrier property may be lowered.

  Furthermore, in this invention, it is preferable that content of said compound is reducing toward the depth direction from the surface of a silicon oxide vapor deposition film in a silicon oxide vapor deposition film. As a result, the impact resistance and the like are enhanced by the above-described compound and the like on the surface of the silicon oxide vapor-deposited film, and on the other hand, since the content of the compound is small at the interface with the base film, the base film and the silicon oxide vapor-deposited film are The tight adhesion is strong.

  In the present invention, the above-described vapor deposition film of silicon oxide uses, for example, a surface analyzer such as an X-ray photoelectron spectrometer (Xray), a secondary ion mass spectrometer (Secondary Ion Mass Spectroscopy, SIMS), or the like. The above-mentioned physical properties can be confirmed by performing analysis such as ion etching in the vertical direction and performing elemental analysis of the silicon oxide deposited film.

  In the present invention, the film thickness of the silicon oxide vapor-deposited film is preferably about 50 to 4000 mm, more preferably 100 to 1000 mm. If it is thicker than 4000 mm, cracks or the like may occur in the film. On the other hand, if it is less than 50 mm, it may be difficult to achieve a barrier effect. The film thickness can be measured by a fundamental parameter method using, for example, a fluorescent X-ray analyzer (model name, RIX2000 type) manufactured by Rigaku Corporation. As a means for changing the film thickness of the silicon oxide vapor deposition film, it is performed by a method of increasing the volume velocity of the vapor deposition film, that is, a method of increasing the amount of monomer gas and oxygen gas or a method of slowing the vapor deposition rate. Can do.

  In the present invention, the silicon oxide vapor deposition film may be not only one layer but also a multilayer film in which two or more layers are laminated, and the organic silicon compound to be used is also used in one kind or a mixture of two or more kinds. You can also.

  In the present invention, as a monomer gas for vapor deposition of an organosilicon 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 Methylcyclotetrasiloxane or the like can be used. Among these, it is particularly preferable to use 1,1,3,3-tetramethyldisiloxane or hexamethyldisiloxane as a raw material because of its handleability and the characteristics of the formed continuous film. In the above, as the inert gas, for example, argon gas, helium gas, or the like can be used.

<4> Gas barrier coating film The gas barrier coating film used in the present invention has a general formula R ¹ _n M (OR ² ) _m (wherein R ¹ and R ² are organic groups having 1 to 8 carbon atoms). M represents a metal atom, n represents an integer of 0 or more, m represents an integer of 1 or more, and n + m represents an atomic valence of M). A gas barrier comprising an alkoxide, a polyvinyl alcohol resin and / or an ethylene / vinyl alcohol copolymer, and further polycondensed by a sol-gel method in the presence of a sol-gel method catalyst, an acid, water, and an organic solvent. It consists of a sex composition. The coating film is obtained by coating the gas barrier composition on the silicon oxide vapor-deposited film on the base film, and having a temperature of 20 to 180 ° C. and not higher than the melting point of the base film, preferably 50 to 160. It can be formed by heat treatment at a temperature in the range of 10 ° C. for 10 seconds to 10 minutes.

Further, two or more gas barrier coating films may be stacked to form a composite polymer layer.
As the alkoxide represented by the above general formula R ¹ _n M (OR ² ) _m , at least one of alkoxide partial hydrolyzate and alkoxide hydrolysis condensate can be used. The partial hydrolyzate is not limited to the one in which all of the alkoxy groups are hydrolyzed, and may be one in which one or more are hydrolyzed, or a mixture thereof, and further a hydrolysis condensate. As a dimer or more of a partially hydrolyzed alkoxide, specifically, a dimer or hexamer may be used.

In the 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. Can be mentioned.

In the 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 which may have a branch. Yes, for example, a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, a sec-butyl group and the like can be mentioned. When a plurality of (OR ² ) are present in the same molecule, (OR ² ) may be the same or different.

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

In this case, the alkoxide that can be preferably used in the present invention includes 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 and dimethyldiethoxysilane (CH ₃ ) ₂ Si (OC ₂ H ₅ ) ₂ .

  In the present invention, a polycondensation product of the above alkoxysilane can also be used, and specifically, for example, polytetramethoxysilane, polytetraemethoxysilane, and the like can be used.

In the present invention, a zirconium alkoxide in which M is Zr can also be suitably used as the alkoxide represented by the general formula R ¹ _n M (OR ² ) _m . For example, tetramethoxyzirconium Zr (OCH ₃ ) ₄ , tetraethoxyzirconium Zr (OC ₂ H ₅ ) ₄ , tetra ipropoxyzirconium Zr (iso-OC ₃ H ₇ ) ₄ , tetra n butoxyzirconium Zr (OC ₄ H ₉ ) ₄ etc. can be illustrated.

Further, as the alkoxide represented by the general formula R ¹ _n M (OR ² ) _m , a titanium alkoxide in which M is Ti can be preferably used. For example, tetramethoxytitanium Ti (OCH ₃ ) ₄ , tetra Examples thereof include ethoxytitanium Ti (OC ₂ H ₅ ) ₄ , tetraisopropoxytitanium Ti (iso-OC ₃ H ₇ ) ₄ , tetra nbutoxytitanium Ti (OC ₄ H ₉ ) _{4 and the} like.

As the alkoxide represented by the general formula R ¹ _n M (OR ² ) _m , an aluminum alkoxide in which M is Al can be used. For example, tetramethoxyaluminum Al (OCH ₃ ) ₄ , tetraethoxyaluminum Al (OC ₂ H ₅ ) ₄ , tetraisopropoxy aluminum Al (iso-OC ₃ H ₇ ) ₄ , tetra n butoxy aluminum Al (OC ₄ H ₉ ) _{4 and the} like can be used.

  In the present invention, two or more of the alkoxides may be used in combination. For example, when alkoxysilane and zirconium alkoxide are mixed and used, the toughness, heat resistance and the like of the resulting gas barrier laminate film layer can be improved.

  As the polyvinyl alcohol resin and / or ethylene / vinyl alcohol copolymer used in the present invention, a polyvinyl alcohol resin or an ethylene / vinyl alcohol copolymer can be used alone, respectively, or polyvinyl alcohol A single resin and an ethylene / vinyl alcohol copolymer can be used in combination. In the present invention, physical properties such as gas barrier properties, water resistance, and weather resistance can be remarkably improved by using a polyvinyl alcohol resin and / or an ethylene / vinyl alcohol copolymer.

  The content of the polyvinyl alcohol resin and / or the ethylene / vinyl alcohol copolymer is in the range of 5 to 500 parts by mass, preferably 20 to 200 parts by mass with respect to 100 parts by mass of the total amount of the alkoxide. The blending ratio of If it exceeds 500 parts by mass, the brittleness of the gas barrier coating film becomes large, and the water resistance, weather resistance, etc. may decrease. On the other hand, if it is less than 5 parts by mass, the gas barrier property may be lowered.

  In the polyvinyl alcohol resin and / or ethylene / vinyl alcohol copolymer, as the polyvinyl alcohol resin, one obtained by saponifying polyvinyl acetate can be generally used. Polyvinyl alcohol resins include partially saponified polyvinyl alcohol resins in which several tens of percent of acetate groups remain, completely saponified polyvinyl alcohols in which no acetate groups remain, and modified polyvinyl alcohol resins in which OH groups have been modified. Well, not particularly limited. Examples of such a polyvinyl alcohol resin include “RS-110 (degree of saponification = 99%, degree of polymerization = 1,000)” manufactured by Kuraray Co., Ltd., and “Kuraray Poval LM-20SO ( “Saponification degree = 40%, polymerization degree = 2,000)”, “GOHSENOL NM-14 (degree of saponification = 99%, polymerization degree = 1,400)” manufactured by Nippon Synthetic Chemical Industry Co., Ltd. Can do.

  As the ethylene / vinyl alcohol copolymer, a saponified product of a copolymer of ethylene and vinyl acetate, that is, a product obtained by saponifying an ethylene-vinyl acetate random copolymer can be used. For example, it is not particularly limited, and includes a partially saponified product in which several tens mol% of acetic acid groups remain to a complete saponified product in which only several mol% of acetic acid groups remain or no acetic acid groups remain. However, it is preferable to use a saponification degree that is preferably 80 mol% or more, more preferably 90 mol% or more, and still more preferably 95 mol% or more from the viewpoint of gas barrier properties. In addition, the content of the repeating unit derived from ethylene in the ethylene / vinyl alcohol copolymer (hereinafter also referred to as “ethylene content”) is usually 0 to 50 mol%, preferably 20 to 45 mol%. It is preferable. Examples of such an ethylene / vinyl alcohol copolymer include “Eval EP-F101 (ethylene content; 32 mol%)” manufactured by Kuraray Co., Ltd., “Soarnol D2908 (ethylene content; 29 mol) manufactured by Nippon Synthetic Chemical Industry Co., Ltd.” %) "And the like.

The gas barrier composition used in the present invention has the general formula R ¹ _n M (OR ² ) _m (wherein R ¹ and R ² represent an organic group having 1 to 8 carbon atoms, M is 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), and Gas barrier properties obtained by polycondensation by a sol-gel method in the presence of a sol-gel method catalyst, an acid, water, and an organic solvent. It is a composition. In preparing the gas barrier composition, a silane coupling agent or the like may be added.

  As the silane coupling agent that can be suitably used in the present invention, known organic reactive group-containing organoalkoxysilanes can be widely used. In addition, the usage-amount of a silane coupling agent exists in the range of 1-20 mass parts with respect to 100 mass parts of said alkoxysilanes. When 20 parts by mass or more is used, the rigidity and brittleness of the formed gas barrier coating film are increased, and the workability of the gas barrier coating film may be lowered.

  The sol-gel catalyst is a catalyst mainly used as a polycondensation catalyst, and a basic substance such as a tertiary amine that is substantially insoluble in water and soluble in an organic solvent is used. For example, N, N-dimethylbenzylamine, tripropylamine, tributylamine, tripentylamine and the like can be used. In the present invention, N, N-dimethylbenzylamine is particularly preferred. The amount of its use is 0.01-1.0 mass part per 100 mass parts of total amounts of an alkoxide and a silane coupling agent.

  The “acid” used in the gas barrier composition is mainly used as a catalyst for hydrolysis of an alkoxide, a silane coupling agent or the like in the sol-gel method. For example, mineral acids such as sulfuric acid, hydrochloric acid and nitric acid, and organic acids such as acetic acid and tartaric acid can be used. The amount of the acid used is preferably 0.001 to 0.05 mol based on the total molar amount of the alkoxide and the alkoxide content of the silane coupling agent (for example, silicate moiety).

  Furthermore, in the above gas barrier composition, water can be used in a proportion of 0.1 to 100 mol, preferably 0.8 to 2 mol, relative to 1 mol of the total molar amount of the alkoxide. When the amount of water exceeds 2 mol, the polymer obtained from the alkoxysilane and the metal alkoxide becomes spherical particles, and the spherical particles are three-dimensionally crosslinked to form a porous polymer having a low density, Such a porous polymer cannot improve the gas barrier property. Moreover, when the amount of water is less than 0.8 mol, the hydrolysis reaction may not easily proceed.

  Furthermore, as an organic solvent used in said gas-barrier composition, methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butanol etc. can be used, for example. The polyvinyl alcohol-based 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, or the like. It can be selected appropriately. For example, when a polyvinyl alcohol resin and an ethylene / vinyl alcohol copolymer are used in combination, n-butanol is preferably used. An ethylene / vinyl alcohol copolymer solubilized in a solvent can also be used. For example, trade name “Soarnol” manufactured by Nippon Synthetic Chemical Industry Co., Ltd. can be preferably used. The amount of the organic solvent used is usually 30 to 500 with respect to 100 mass of the total amount of the alkoxide, silane coupling agent, polyvinyl alcohol resin and / or ethylene / vinyl alcohol copolymer, acid and sol-gel catalyst. Part by mass.

In this invention, in order to form a silicon oxide vapor deposition layer in a base film and then to form a gas barrier coating film, it can manufacture with the following method.
First, an alkoxide such as alkoxysilane, a silane coupling agent, a polyvinyl alcohol resin and / or an ethylene / vinyl alcohol copolymer, a sol-gel catalyst, an acid, water, an organic solvent, and, if necessary, a metal alkoxide Etc. are mixed to prepare a gas barrier composition. By mixing, the gas barrier composition (coating liquid) starts and proceeds with a polycondensation reaction.

  Next, the gas barrier composition is applied onto the silicon oxide vapor-deposited film on the base film layer by a conventional method and dried. By this drying step, polycondensation of the alkoxide such as alkoxysilane, metal alkoxide, silane coupling agent, polyvinyl alcohol resin and / or ethylene / vinyl alcohol copolymer further proceeds, and a coating film is formed. . On the first coating film, the above coating operation may be further repeated to form a plurality of coating films composed of two or more layers.

  Next, the base film layer coated with the gas barrier composition is heated for 10 seconds to 10 minutes at a temperature of 20 to 180 ° C. and below the melting point of the base film layer, preferably in the range of 50 to 160 ° C. To process. Thereby, one or more gas barrier coating films of the gas barrier composition can be formed on the silicon oxide vapor deposition film.

  In the present invention, the gas barrier coating film has a dry film thickness of 0.01 to 50 μm, preferably 30 μm or less, preferably 0.1 to 10 μm in order to ensure the flexibility of the film and prevent the occurrence of cracks. It is. If it is thinner than 0.01 μm, it cannot function as a coating layer for protecting the silicon oxide vapor-deposited film.

<5> Aluminum oxide vapor deposition film In the barrier film for paper containers of the present invention, the vapor deposition film provided on the gas barrier coating film is formed by depositing an inorganic oxide by various chemical vapor deposition methods or physical vapor deposition methods. Although it can be provided, in particular, it is preferable to provide an aluminum oxide vapor deposition film by a physical vapor deposition method because of easy handling as a vapor deposition material.
The aluminum oxide vapor-deposited film can be produced by forming a single layer film composed of one layer of an aluminum oxide vapor-deposited film or a multilayer film composed of two or more layers by physical vapor deposition.

  An aluminum oxide vapor deposition film formed by physical vapor deposition is excellent in adhesion to the gas barrier coating film surface. Further, the aluminum oxide vapor deposition film improves the surface wettability of the gas barrier coating film surface and increases the affinity with a heat-fusible resin used as an adhesive when laminating with a paper substrate.

  Therefore, by laminating a paper base material on the aluminum oxide vapor-deposited film through a heat-fusible resin, a strong interlayer bond is obtained, and no delamination phenomenon is observed between the layers. In addition, an extremely useful barrier film having excellent gas barrier properties can be produced. The gas barrier coating film, the aluminum oxide vapor deposition film, and the heat-fusible resin layer work effectively with each other, exhibit a synergistic effect, and form a strong interlayer bond. Therefore, it is not necessary to perform any surface treatment between them to enhance interlayer adhesion strength such as ozone treatment.

  The aluminum oxide vapor deposition film itself exhibits gas barrier properties. Therefore, by using the laminated material instead of various surface treatments for increasing the interlayer adhesive strength, not only delamination at the interface is prevented but also the gas barrier property of the laminated material is enhanced.

  In the present invention, examples of such physical vapor deposition include physical vapor deposition (Physical Vapor Deposition, PVD) such as vacuum deposition, sputtering, ion plating, and ion cluster beam. It is done.

  Specifically, a vacuum deposition method in which aluminum or an oxide thereof is used as a raw material, is heated and vaporized, and is vapor-deposited on one of the base films, for example, aluminum or an oxide thereof is used as the raw material. Forming a vapor deposition film using an oxidation reaction vapor deposition method in which oxygen is introduced and oxidized to deposit on one side of the base film, and further, a plasma-assisted oxidation reaction vapor deposition method in which the oxidation reaction is supported by plasma. Can do. In addition, as a heating method of the vapor deposition material, for example, a resistance heating method, a high frequency induction heating method, an electron beam heating method (EB), or the like can be used.

  A method for forming a thin film of an inorganic oxide by physical vapor deposition will be described with reference to FIG. 4 showing a schematic configuration diagram showing an example of a take-up vacuum deposition apparatus.

  First, the base film 11 fed out from the unwinding roll 43 in the vacuum chamber 42 of the wind-up type vacuum vapor deposition apparatus 41 is guided to the cooled coating drum 46 through the guide rolls 44 and 45. An evaporation source 48 heated by a crucible 47, for example, metal aluminum or aluminum oxide is evaporated on the substrate film 11 guided on the cooled coating drum 46, and if necessary, For example, an aluminum oxide vapor deposition film is formed through the masks 50 and 50 while supplying oxygen gas or the like from the oxygen gas outlet 49, and then, for example, an aluminum oxide vapor deposition film is formed in the above. When the formed base film 11 is sent out through the guide rolls 51 and 52 and wound up on the take-up roll 53, an aluminum oxide vapor deposition film can be formed by physical vapor deposition.

The aluminum oxide vapor deposition film may basically be a thin film on which aluminum oxide AlO _x is vapor deposited. Here, in order to improve the interlayer adhesion strength, the value range of X is preferably 1.5 or less, and more preferably in the range of 0.5 to 1.5 from the viewpoint of transparency. It is.

  Moreover, in this invention, the film thickness of an aluminum oxide vapor deposition film is 2-200 nm, for example, More preferably, it is 10-50 nm. If it is thinner than 2 nm, sufficient interlayer adhesion strength cannot be obtained. Further, even if it is thicker than 200 nm, no further improvement in interlayer adhesion strength can be expected. Furthermore, since the flexibility of the film is reduced, cracks are likely to occur.

<6> Outermost layer In the laminated material for paper containers of the present invention, the outermost layer is a layer made of a polyolefin-based resin having various heat sealing properties that can be melted by heat and fused to each other. 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 Polyolefin resins such as methylpentene polymer, polybutene polymer, polyethylene or polypropylene modified with an unsaturated carboxylic acid such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, itaconic acid, Vinyl acetate resin (Meth) can be used acrylic resin, resins such as polyvinyl chloride resin. In the present invention, one or more of the above-mentioned resins are used, melt-extruded using an extruder or the like, and melt-extruded and laminated on the paper substrate layer via an anchor coat layer or the like. Or by using one or more of the above-mentioned resins, and producing a resin film or sheet from the resin in advance, with the resin film or sheet interposed through an adhesive layer for laminating, etc. Thus, the outermost layer can be formed by dry lamination on the paper base material layer. In the present invention, the thickness of the outermost layer is about 5 to 200 μm, preferably about 10 to 100 μm.

<7> Paper base material layer In the laminated material for paper containers of the present invention, any paper base material can be used for the paper base material 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 sufficiently high formability, bending resistance, rigidity, waist and strength. Examples of such a paper base material include, but are not limited to, a strong sized bleached or unbleached paper base material, or various paper base materials such as pure white roll paper, kraft paper, paperboard, and processed paper. About 80 to 600 g / m ² , preferably about 100 to 450 g / m ² basis weight can be suitably used.

  Furthermore, the paper base material of the liquid paper container needs to have a certain thickness so as to give sufficient strength to accommodate the liquid. Since the barrier film for paper containers of the present invention can be bonded to such a thick paper base material with high interlayer adhesive strength, the paper container comprising this can be used in various packaging applications for containing liquids. Can be suitably used. Moreover, it can be set as the form which can become independent, such as a cube.

<8> Heat-fusible resin layer In the laminated material for paper containers of the present invention, as the heat-fusible resin constituting the heat-fusible resin layer, an ethylene-based resin having a carboxyl group or an acid anhydride group in the molecule Polymers are preferably used.

The ethylene-based polymer exhibits excellent interlayer adhesion strength with both the paper base material and the aluminum oxide vapor deposition film by melt extrusion between the paper base material layer and the aluminum oxide vapor deposition film of the barrier film. be able to.
Examples of such a polymer include a copolymer of ethylene and an unsaturated carboxylic acid or an anhydride thereof.

  The unsaturated carboxylic acid or its anhydride is a compound having at least one carboxyl group or acid anhydride group in the molecule, and specifically includes acrylic acid, methacrylic acid, maleic acid, maleic anhydride. , 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 aluminum oxide vapor deposition film.

  In the copolymer, the ratio of ethylene and unsaturated carboxylic acid or anhydride thereof, the melt flow rate (MFR), and the like can be appropriately determined by those skilled in the art according to the properties of the paper substrate used. it can.

  In the present invention, the thickness of the heat-fusible resin layer as described above is preferably 10 to 50 μm from the viewpoint of film forming properties, and a uniform film thickness can be obtained within this range. Moreover, as said thickness, 15-35 micrometers is especially preferable. If the heat-fusible resin layer is thinner than 10 μm, sufficient adhesion cannot be obtained.

<9> Innermost layer In the laminated material for paper containers of the present invention, the innermost layer may be made of any resin that can be melted by heat and fused to each other. Specifically, the same resin as the outermost layer described above can be used.

One or more of these resins are used and melt-extruded with an extruder or the like, and on the surface opposite to the aluminum oxide vapor deposition film of the barrier film of the present invention (surface on the base film side). The innermost layer can be provided by melt extrusion lamination. Alternatively, a resin film or sheet may be produced from one or more of the above resins, and this may be dry laminated on the surface via an adhesive layer for laminating. In some cases, various surface treatments such as applying an anchor coating agent to the laminated surface in advance may be performed.
Further, the innermost layer may have a multilayer structure of two or more by co-extrusion of one or more kinds of resins.

In order to form the innermost layer of the present invention, low density polyethylene can be preferably used, and particularly preferably, linear (linear) low density polyethylene polymerized using a metallocene catalyst is used. it can. Since these resins exhibit low-temperature sealing properties, it is possible to prevent cracks and the like from being generated due to an excessive heat load applied to the vapor deposition film of the inner layer during lamination or box making. In addition, there is an advantage that generation of pinholes can be prevented, and poor sealing and liquid leakage can be avoided. In order to obtain a desired property, the above resin can be blended with another resin. Various additives such as antioxidants, UV absorbers, antistatic agents, anti-blocking agents, lubricants (fatty acid amides), 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 10 μm to 300 μm, preferably 20 μm to 100 μm, in order to prevent poor sealing.

<10> Box Making At least the outermost layer, the paper base layer, the heat-fusible resin layer, the barrier layer made of a barrier film, and the innermost layer are sequentially laminated, and the aluminum oxide vapor deposition film of the barrier film The laminated material of the present invention, which is laminated so that the surface faces the heat-fusible resin layer and is in direct contact therewith, can be subjected to box making to form a paper container, particularly a liquid paper container.

The paper container may be of any type such as, for example, a brick type, a flat type, or a gable top type. Further, the shape can be any of a rectangular 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 foods and drinks, chemicals such as adhesives and pressure-sensitive adhesives, cosmetics, and miscellaneous goods such as pharmaceuticals. In particular, for example, it is useful as a liquid paper container for filling and packaging various liquid foods and drinks such as juices such as liquor and fruit juices, mineral water, soy sauce, sauces and soup, or curry, stew and soup. Is.
EXAMPLES The present invention will be specifically described below with reference to examples, but these do not limit the present invention.

[Example 1]
(1) Using a biaxially stretched polyethylene terephthalate (PET) film having a corona-treated surface on one side and having a thickness of 12 μm, this is mounted on a delivery roll of a plasma chemical vapor deposition apparatus, and then under the conditions shown below: A silicon oxide vapor deposition film having a thickness of 10 nm was formed on the corona-treated surface of the film.

That is, hexamethyldisiloxane as a raw material is introduced into the corona-treated surface, the amount of introduced gas hexamethyldisiloxane: oxygen gas: helium = 1.0: 1.5: 1.0 (unit: slm), The degree of vacuum was 2 to 6 × 10 ⁻⁶ mBar, the degree of vacuum in the deposition chamber was 2 to 5 × 10 ⁻³ mBar, and the cooling / electrode drum supply power was 10 kW.

Next, immediately after the silicon oxide vapor deposition film having a thickness of 10 nm is formed, a glow discharge plasma generator is used on the surface of the silicon oxide vapor deposition film, and the power is 8 kW, oxygen gas (O ₂ ): argon gas (Ar) = A mixed gas of 0.7: 0.1 (unit: slm) was introduced, and plasma treatment was performed to improve the surface tension of the deposited silicon oxide film surface by 54 dyn / cm or more to form a plasma treated surface.

(2) Next, a preliminarily prepared hydrolyzate of composition b was added to the mixture of composition a prepared according to the composition shown in Table 1 and stirred to obtain a colorless and transparent gas barrier composition.

  Using the barrier composition produced above, this was coated on the plasma-treated surface of (1) by the direct gravure method, and then heat-treated at 140 ° C. for 60 seconds to obtain a thickness of 0.3 μm ( A gas barrier coating film in a dry operation state was formed.

(3) A plasma treatment was performed on the gas barrier coating film formed in (2) above using a glow discharge plasma generator and applying argon 1.0 slm and current 20 A. Thereafter, an aluminum oxide vapor deposition film having a thickness of 20 nm was formed on the plasma-treated surface by using an electron beam heating vacuum deposition method. The degree of vacuum in the vacuum chamber was 2 × 10 ⁻⁴ mbar, and the degree of vacuum in the deposition chamber was 2.0 × 10 ⁻² mbar.
Thereby, the barrier film of the present invention was obtained.

(4) An anchor coating agent is gravure coated on the non-coated surface (non-corona-treated surface) of the biaxially stretched PET film of the barrier film obtained above, and the anchor has a thickness of 0.1 g / m ² (dry state). A coat layer was provided. Next, an ethylene-α / olefin copolymer film (m-PEF) (thickness 60 μm) polymerized using a metallocene catalyst is opposed to the surface of the barrier film provided with the anchor coat layer, and sandwich lamination is performed. And laminated through polyethylene (extrusion film thickness: 20 μm).

(5) On the other hand, after corona discharge treatment was performed on one surface of a paper substrate (thickness: 385 μm), a low density polyethylene resin (extrusion temperature: 320 ° C., extrusion film thickness: 25 μm) was formed on the corona discharge treatment surface. This was extrusion coated to form the outermost layer.

(6) A gravure coat of a polyethyleneimine-based anchor coat agent is provided on the non-coated surface of the paper substrate to provide an anchor coat layer having a film thickness of 0.1 g / m ² (in a dry state). The aluminum oxide vapor-deposited film surface of the barrier film is opposed to the surface, and an ethylene / methacrylic acid copolymer (EMAA, Nucrel N-1108C manufactured by Mitsui DuPont Polychemical Co., Ltd.) (extrusion temperature: 295 ° C., extrusion) (Film thickness: 20 μm) are melt extruded and laminated by sandwich lamination, PE 25 μm / paper substrate 385 μm / anchor coat layer / EMAA 20 μm / aluminum oxide deposition film 20 nm / gas barrier coating film 0.3 μm / silicon oxide deposition film 10 nm / biaxial Stretched PET film 12 μm / anchor coat layer / PE 20 μm / m-PEF 60 μm A laminated material was obtained.

(7) Using the above laminated material, in accordance with the shape of the gobeltop type liquid paper container, a fold ruled line is formed in a vertical, horizontal, or slanted shape, and a blank plate having an adhesive margin is formed by punching. The end surface of the blank plate is subjected to skive and hemming treatment to prevent penetration of contents, liquid leakage, etc., and then subjected to end surface treatment. Part of the m-PEF was melted, and the other end of the blank plate was superposed on the melted surface and bonded together to form a cylinder-sealed seal portion to produce a cylindrical sleeve. The inner surface of the bottom of the cylindrical sleeve manufactured above is blown with hot air, the m-PEF on the inner surface is melted, press sealed to form the bottom seal portion, and juice juice is filled from the other opening After that, the inner surface of the top is scooped with hot air, m-PEF on the inner surface is melted, press-sealed to form a gobble top seal portion, and the sealed liquid paper according to the present invention filled and packaged with the contents A container was manufactured.

[Comparative Example 1]
In the step (3) of Example 1 above, instead of forming an aluminum oxide vapor deposition film on the surface of the gas barrier coating film after the plasma treatment, a urethane-based primer (CVD primer manufactured by DIC Graphics Co., Ltd. ( 12)) was coated by a direct gravure method to form a primer coat layer (0.25 μm), and further subjected to ozone treatment, in the same manner as in Example 1, except that the primer coat layer / gas barrier coating film was 0.5. A barrier film consisting of 3 μm / silicon oxide vapor-deposited film 10 nm / biaxially stretched PET film 12 μm was obtained.

  In the same manner as in Example 1, a paper base material was sandwich-laminated on the ozone-treated surface of the primer coat layer of the barrier film via EMAA. Also, an anchor coat layer is provided on the surface of the biaxially stretched PET film of the barrier film, and m-PEF is sandwich-laminated through PE, and PE 25 μm / paper substrate 385 μm / anchor coat layer / EMAA 20 μm / primer coat A laminate comprising: layer / gas barrier coating film 0.3 μm / silicon oxide vapor deposition film 10 nm / biaxially stretched PET film 12 μm / anchor coat layer / PE 20 μm / m-PEF 60 μm was obtained.

[Comparative Example 2]
In Example 1, the gas barrier coating film was not provided, and the aluminum oxide vapor deposition film was directly provided on the silicon oxide vapor deposition film, and the aluminum oxide vapor deposition film 20 nm / silicon oxide vapor deposition film 10 nm was obtained in the same manner as in Example 1. / The barrier film which consists of 12 micrometers of biaxially-stretched PET films was obtained.

  In the same manner as in Example 1, a paper substrate was sandwich-laminated on the surface of the aluminum oxide deposited film of the barrier film via EMAA. In addition, an anchor coat layer is provided on the surface of the biaxially stretched PET film of the barrier film, and m-PEF is sandwich-laminated through PE to obtain PE 25 μm / paper substrate 385 μm / anchor coat layer / EMAA 20 μm / aluminum oxide. A laminated material consisting of a deposited film 20 nm / silicon oxide deposited film 10 nm / biaxially stretched PET film 12 μm / anchor coat layer / PE 20 μm / m-PEF 60 μm was obtained.

[Evaluation]
(1) Interlayer adhesion strength test About each of the barrier films manufactured in Example 1 and Comparative Example 1, the surface of the aluminum oxide vapor deposition film (Example 1) or the surface of the primer coat layer (Comparative Example 1) is EMAA So that the resin temperature of EMAA is 295 ° C. and the resin thickness is 20 μm, and the tensile tester (Tensilon Universal Tester RTC1310A, manufactured by Orientec Co., Ltd.) is used, and the peeling speed is 50 mm / min. A peel test was conducted to measure the peel strength (N / 15 mm) per 15 mm between the biaxially stretched PET film and EMAA.
The results are shown in Table 2.

(2) Gas barrier property test Oxygen permeability measurement:
About each of the laminated material manufactured in Example 1 and Comparative Example 1, under the conditions of a temperature of 23 ° C. and a humidity of 90% RH, a measuring machine (model name, OXTRAN) manufactured by MOCON, USA, JIS K In accordance with 7126, the oxygen permeability was measured (number of samples N = 10). The results are shown in Table 3.
Measurement of water vapor permeability:
About each of the laminated material manufactured in Example 1 and Comparative Example 1, under the conditions of a temperature of 40 ° C. and a humidity of 100% RH, in a measuring machine (model name, PERMATRAN) manufactured by MOCON, USA, JIS K In accordance with 7129, water vapor permeability was measured (number of samples N = 10). The results are shown in Table 3.

(3) Weight loss test Using the laminates produced in Example 1, Comparative Example 1 and Comparative Example 2, 900 ml carton and 2000 ml carton were prepared and filled with sake and sealed. Subsequently, after leaving this to stand in 60 degreeC oven for 15 days, mass was measured and the weight loss value from the mass immediately after filling was calculated | required. The results are shown in Table 4.

  The barrier film for paper containers of the present invention showed higher interlayer adhesion strength than the comparative example. In addition, after the lamination process and the box making process, high gas barrier properties, in particular, water vapor barrier properties were exhibited, and the contents were more excellently protected than the comparative examples.

a. Silicon oxide vapor deposition film b. Gas barrier coating film c. Aluminum oxide deposited film d. 1. Base film Outermost layer 2. 2. Paper base material layer 3. Heat-sealable resin layer 4. Barrier layer Innermost layer 11. Base film 21. Plasma chemical vapor deposition apparatus 22. Vacuum chamber 23. Unwinding roll 24. Auxiliary roll 25. Cooling / electrode drum 26, 27. Gas supply device 28. Raw material volatilization supply device 29. Raw material supply nozzle 30. Glow discharge plasma 31. Power supply 32. Magnet 33. Auxiliary roll 34. Take-up roll 35. Vacuum pump 41. Winding type vacuum deposition apparatus 42. Vacuum chamber 43. Unwinding rolls 44, 45. Guide roll 46. Coating drum 47. Crucible 48. Deposition source 49. Oxygen gas outlet 50. Masks 51, 52. Guide roll 53. Winding roll

Claims (4)

On one side of the base film,
(A) a silicon oxide vapor deposition film formed by a chemical vapor deposition method;
(B) the general formula _{^{R 1 n M (OR 2)}} m ( where in the formula, R ^1, R ² represents an organic group having 1 to 8 carbon atoms, M represents a metal atom, n is 0 And m represents an integer of 1 or more, and n + m represents a valence of M), a polyvinyl alcohol resin and / or ethylene / vinyl alcohol copolymer. A gas barrier coating film comprising a gas barrier composition obtained by polycondensation by a sol-gel method, and
(C) an aluminum oxide vapor deposition film formed by physical vapor deposition,
Are laminated in this order, and (c) the barrier film for paper containers laminated so that the aluminum oxide vapor deposition film becomes the outermost surface of the barrier film. At least the outermost layer,
Paper base layer,
Heat-fusible resin layer,
A barrier layer comprising the barrier film for a paper container according to claim 1, and
Innermost layer,
Were laminated in order, and the aluminum oxide vapor deposition film surface of the paper container barrier film was laminated so that it was opposed to the heat-fusible resin layer and directly in contact with the heat-fusible resin layer. Laminated material for paper containers.   The paper container according to claim 2, wherein the heat-fusible resin constituting the heat-fusible resin layer is an ethylene polymer having a carboxyl group or an acid anhydride group in the molecule. Laminated material.   A liquid paper container obtained by boxing the laminated material according to claim 2.