JP2007176539A - Paper container, and method for manufacturing paper container - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a paper container having a barrier layer in which the barrier property is high, and cracks hardly occur in the manufacturing process of the paper container. <P>SOLUTION: The paper container consists of a laminate 10 in which at least an outermost layer 11 consisting of a thermoplastic resin, a base material layer 12 consisting of a paper base material, a barrier layer 14 and an innermost layer 15 consisting of a thermoplastic resin are successively laminated. In the barrier layer 14, a thin film 14a consisting of two or more kinds of inorganic oxides is formed on the surface of the plastic film 14b. The thin film 14a consisting of the inorganic oxides is preferably a thin film containing at least silicon oxide and aluminum oxide, and more preferably, a thin film with silicon oxide and aluminum oxide being vapor-deposited in a mixed state. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a paper container and a method for manufacturing the paper container, and more particularly to a paper container having a high barrier property and a method for manufacturing the same.

In general, a liquid paper container is formed using various laminates in order to ensure the storage stability of the contents, the strength as a container, and the like. As a laminate used for the liquid paper container, a laminate having a configuration of an outer surface sealant layer / paper layer / barrier layer / inner surface sealant layer is known, and specifically, polyethylene (PE) / paper / PE. , PE / paper / PE / Al / PE, PE / paper / PE / Al / polyester (PET) / PE, PE / paper / PE / Si / polyester (PET) / PE, etc. Widely used. Specifically, Patent Document 1 discloses a barrier layer in which silicon oxide or aluminum oxide is deposited on a film. Patent Document 2 discloses a paper container formed by molding a laminate of an alumina-deposited plastic film and a base paper.
JP 2002-127329 A JP-A-8-183139

As described in Patent Document 2, a laminate using an alumina-deposited plastic film is cracked by friction, bending, and stretching, and deteriorates barrier properties. Therefore, the base paper density of the base material that can be used is 0.95 g / It was necessary to make it cm ³ or less. This is due to the fact that cracks are likely to occur and the barrier properties are likely to deteriorate in the process of putting ruled lines that are creases in the laminate and the process of folding and assembling the laminate.

  Therefore, the present invention has an object to provide a paper container having a barrier layer that has a high barrier property and is difficult to cause cracks or the like in the manufacturing process of the paper container, and a method for manufacturing the same, without specifying the base paper density of the base material. To do.

  The paper container of the present invention that solves the above-mentioned problems comprises a laminate in which at least an outermost layer made of a thermoplastic resin, a base material layer made of a paper base material, a barrier layer, and an innermost layer made of a thermoplastic resin are sequentially laminated. In the paper container, the barrier layer is formed by forming a thin film composed of two or more kinds of inorganic oxides on the surface of a plastic film.

  According to this, by using a plurality of types of inorganic oxides for the barrier layer, the paper container having a barrier layer that matches the characteristics of each inorganic oxide, has high barrier properties, and is difficult to crack or the like in the paper container manufacturing process. Can be provided. Such a paper container can be provided even if the density of the base paper is not within a predetermined range.

  In the paper container of the present invention, the thin film made of the inorganic oxide is a thin film containing at least silicon oxide and aluminum oxide.

  According to this, the inclusion of silicon oxide makes it possible to form a thin film that has high barrier properties and is less prone to cracks or the like when the laminate is deformed by bending or stretching. Moreover, the material cost as a whole becomes low by including aluminum oxide. Furthermore, a paper container having improved acid resistance can be provided by using a combination of silicon oxide and aluminum oxide.

  In the paper container of the present invention, the thin film made of an inorganic oxide is deposited by mixing the silicon oxide and the aluminum oxide.

  According to this, in particular, the barrier layer is formed by vapor deposition in a mixed state of silicon oxide and aluminum oxide to form a dense structure, so that the barrier property is particularly high, and cracks and the like enter in the paper container manufacturing process. A paper container having a difficult barrier layer.

  In the paper container of the present invention, the plastic film is biaxially stretched polyethylene terephthalate or nylon. According to this, the heat-resistant pinhole suitability of the paper container becomes good.

  In the paper container of the present invention, the innermost layer is made of an ethylene / α-olefin copolymer polymerized using a single site catalyst. According to this, since the sealing temperature can be lowered, it becomes difficult to make a hot pinhole.

  The paper container of the present invention is characterized in that an adhesive layer is provided between the base material layer and the barrier layer.

  According to this, the adhesion between the base material layer and the barrier layer is increased, and it is possible to produce a laminate that is not easily deformed when the laminate is deformed to form a paper container. In addition, when the paper base is heated, the moisture contained in the paper base is heated, and this is vaporized and tends to escape to the inner and outer surfaces of the laminated material. Although a foaming phenomenon occurs in which the laminated resin film is pushed up to swell, the adhesive layer is also a layer that relieves such a foaming phenomenon.

  The method for producing a paper container of the present invention that solves the above problems is a laminate in which at least an outermost layer made of a thermoplastic resin, a base material layer made of a paper base material, a barrier layer, and an innermost layer made of a thermoplastic resin are sequentially laminated. A method for producing a paper container comprising a body, wherein the barrier layer is formed by vapor deposition in a state where two or more kinds of inorganic oxides are mixed on the surface of a plastic film.

  According to this, by depositing a plurality of types of inorganic oxides on a plastic film and using them as a barrier layer, the characteristics of each inorganic oxide are matched, the barrier property is high, and cracks occur in the paper container manufacturing process. Thus, it is possible to provide a paper container having a barrier layer that is difficult to enter.

  According to the paper container of the present invention, by using a plurality of types of inorganic oxides in the barrier layer, the characteristics of each inorganic oxide are matched, the barrier property is high, and the barrier is less likely to enter cracks in the paper container manufacturing process. A paper container having a layer can be provided. The same paper container can also be provided by the method for manufacturing a paper container of the present invention.

  Hereinafter, an example of an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is an explanatory view showing an example of a layer structure of a laminate forming the container of the present invention.

  As shown in FIG. 1, the laminate 10 forming the paper container of the present invention comprises at least an outermost layer 11 made of a thermoplastic resin, a base material layer 12 made of a paper base material, a barrier layer 14, and a thermoplastic resin. The innermost layer 15 is sequentially laminated. In addition, as shown in FIG. 1, the laminate 10 preferably has an adhesive layer 13 between the base material layer 12 and the barrier layer 14. Below, each layer which comprises the laminated body 10 is demonstrated.

The outermost layer 11 is made of a thermosetting resin, protects the outside of the base material layer 12, and is heated and bonded to the innermost layer 15 described later at the end portion of the laminate 10. As the thermosetting resin, polyethylene is mainly used, and low density polyethylene (LDPE), specifically high-pressure ethylene homopolymer, or ethylene and propylene, butene, pentene, hexene, octene, 4-methylpentene- A linear low-density polyethylene that is a copolymer with an α-olefin other than ethylene such as 1 is preferably used. The density of this thermoplastic resin is not particularly limited, but is usually about 0.88 to 0.930 g / cm ³ , and its melt index M.I. I. Although it is not specifically limited, Usually, it is about 0.1-20.

  Although the formation method of the outermost layer 11 is not specifically limited, For example, it forms by carrying out the extrusion coating to one side of the base material layer 12. FIG. The outermost layer 11 is a layer that becomes the surface of the paper container, but a printing layer can be further provided on the surface, and the surface is subjected to, for example, corona treatment in order to improve the adhesion of the printing ink used for the printing layer. It is preferable to perform a surface treatment. Although the thickness of the outermost layer 11 is not specifically limited, Usually, it is about 10-50 micrometers.

The base material layer 12 is made of a paper base material. Since this paper base material is a basic material constituting the paper container, it is possible to use a material having formability, flex resistance, rigidity, waist, strength, and the like. it can. Examples of the paper base material are main strength materials, and high-size bleached or unbleached paper base materials, or various paper base materials such as pure white roll paper, kraft paper, paperboard, processed paper, and milk base paper. Can be used. The base material layer 12 may be a stack of these paper base materials. Further, the paper substrate has a weight of about 80 to 600 g / m ² , preferably a weight of about 100 to 450 g / m ² , and a thickness of about 80 to 800 μm, preferably about 100 to 600 μm can be used. . Note that, for example, letters, figures, symbols, and other desired patterns can be arbitrarily formed on the paper base by a normal printing method.

The adhesive layer 13 is a layer that is optionally provided on the laminate 10 that forms the paper container of the present invention, and is used to firmly bond the inorganic oxide vapor-deposited layer 14 a and the base material layer 12. Examples of the material of the adhesive layer 13 include EMAA represented by acid copolymer (or terpolymer), EAA, LLDPE having a density of 0.915 g / cm ³ or less, LLDPE having no additive, LDPE, ionomer resin, polyethylene, polypropylene, and the like. Acid-modified polyolefin resins obtained by modifying polyolefin resins with unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, and itaconic acid, maleic anhydride, and the like are used. Examples of the acid copolymer-based adhesive resin include ethylene / methacrylic acid copolymer, ethylene / methacrylic acid ester copolymer, ethylene / methacrylic acid / methacrylic acid ester terpolymer, and ethylene / methacrylic acid to the above copolymer. A resin mixed with an acid copolymer is used. As the material for the adhesive layer 13, an acid copolymer or terpolymer represented by EMAA is preferably used.

  Although the formation method of the contact bonding layer 13 is not specifically limited, For example, it forms by carrying out extrusion coating to the surface which does not have the outermost layer 11 of the base material layer 12. FIG. The extrusion temperature of the adhesive layer 13 is desirably set to a resin temperature of 300 ° C. or lower in order to prevent deterioration of barrier properties. Although the thickness of the contact bonding layer 13 is not specifically limited, Usually, it is about 15-100 micrometers.

  In addition to the role of bonding the base material layer 12 and the barrier layer 14, the adhesive layer 13 heats moisture contained in the paper base material when the paper base material 12 is heated, Thus, there is also an action to alleviate the foaming phenomenon (bubbling) in which the resin film laminated on the inner and outer surfaces of the paper base 12 is pushed up and swells by trying to come out to the inner and outer surfaces of the laminated material. In order to suppress this bubbling, the thickness of the adhesive layer 13 is desirably 20 μm or more. Even if extrusion is performed at 300 ° C. or lower, barrier deterioration may occur when the thickness is large. Therefore, the resin is extruded thickly onto the base material layer 12 in advance, and then the PE surface of the base material layer 12 and the vapor deposition film are applied. Sand lamination may be performed with a low film thickness. At that time, if the barrier layer 14 is coated in advance with polyethyleneimine or the like, even a resin such as low-density polyethylene is easily bonded.

  In addition, when laminating the paper layer 12 and the barrier layer 14 described later using the adhesive layer 13, the surface of the paper layer 12 may be subjected to a surface treatment such as a corona treatment, a flame treatment, or an anchor coat treatment. Preferably, corona treatment is preferably performed inline on the surface of the barrier layer 14, and ozone treatment or the like is performed on the barrier layer 14 side of the adhesive layer 13.

  The barrier layer 14 is provided to prevent permeation of gas (oxygen or carbon dioxide) or liquid and to maintain the flavor of the contents. As the barrier layer 14, a layer in which a thin film 14 a made of two or more kinds of inorganic oxides is formed on the surface of a plastic film 14 b is used. The thin film 14a is on the side in contact with the base material layer 12.

As the inorganic oxide of the thin film 14a, silicon oxide, aluminum oxide, magnesium oxide, or the like can be used. Among these, two or more types of inorganic oxides are selected, and the thin film 14a is formed on the plastic film 14b. A thin film 14a (a thin film made of a binary inorganic oxide) made of two kinds of inorganic oxides of silicon oxide and aluminum oxide is preferably used. In order to form these inorganic oxide thin films 14a, as raw materials for the thin film 14a, various silicon oxides such as SiO and SiO ₂ and mixtures thereof are used as silicon oxide, and AlO is used as aluminum oxide. And various aluminum oxides such as Al ₂ O ₃ or a mixture thereof, and MgO or the like is used as the magnesium oxide.

  When silicon oxide and aluminum oxide are used in combination, the content of aluminum oxide in the thin film 14a is preferably 10 to 60% by mass. When the content of aluminum oxide is less than 10% by mass, the gas barrier property is inferior, and when it exceeds 60% by mass, the flexibility of the deposited film is lowered, and it becomes weak against bending and dimensional change of the produced laminate 10, so that the barrier is deteriorated. It is easy to cause. The aluminum oxide content can be measured by a conventionally known method.

  When silicon oxide and aluminum oxide are used in combination, a soft and dense thin film 14a is formed by adding silicon oxide to hard and easily cracked aluminum oxide, and has good barrier properties and good flexibility. A barrier layer 14 can be formed. Furthermore, when such a thin film 14a is used, the thin film 14a is colorless and transparent, the barrier deterioration due to bending / stretching of the produced laminate 10 is small, and a ceramic (metal oxide) is used as a raw material. Therefore, it has advantages such as excellent acid resistance compared to an aluminum oxide film formed by oxidizing metal aluminum, and inexpensive materials.

  In addition, in the thin film which vapor-deposited only silicon oxide, the barrier property is high, but the vapor deposition layer is yellowish, the silicon oxide is expensive, or the film thickness is increased in order to obtain a uniform barrier layer. Since it is necessary, film formation takes time and productivity may be low. In addition, in a thin film in which only aluminum oxide is vapor-deposited, a vapor-deposited layer having a barrier property can be formed, and although the transparency is high and the material is inexpensive, the laminated body 10 has a ruled line because the film quality is firm and brittle. In the step of inserting or folding the laminate 10 and assembling the paper container, cracks are likely to occur due to friction, bending, and stretching, and the barrier is likely to be lowered.

The method for forming the thin film 14a is not particularly limited as long as it is a technique for forming a thin film by simultaneously using a plurality of types of thin film materials, but an evaporation method, specifically, a vacuum evaporation method, a sputtering method, an ion plate, or the like. A physical vapor deposition method such as a ting method or a CVD method (chemical vapor deposition method) is used. It is preferable to form a thin film 14a by vapor deposition in a mixed state of silicon oxide and aluminum oxide. For example, when forming the thin film 14a by using a vacuum vapor deposition method, SiO ₂ and Al ₂ O ₃ are used as vapor deposition materials. It is preferable to use a mixture or a mixture of SiO ₂ and Al. By using multi-source deposition, cost can be reduced and barrier properties can be improved.

  The film thickness of the thin film 14a made of an inorganic oxide is 100 to 5000 A (angstrom). If the film thickness is less than 100 A, the gas barrier property is inferior, and even if it exceeds 5000 A, the barrier property is not relatively improved, and the produced laminate 10 is susceptible to bending and dimensional changes, and cracks are likely to occur.

  The plastic film 14b is not particularly limited as long as it is a film made of plastic, but a film made of polyester, particularly polyethylene terephthalate (PET), nylon, polypropylene, ethylene-vinyl alcohol copolymer, polyvinylidene chloride, polyacrylonitrile, or the like is used. It is done. Of these, it is preferable to use biaxially stretched polyethylene terephthalate or nylon as the plastic film 14b. By using this plastic film, the heat-resistant pinhole suitability is improved. Further, by using the plastic film 14b on which multiple inorganic oxides are vapor-deposited as the barrier layer 14 of the laminated body 10 of the paper container, cracks due to ruled lines or the like hardly occur at the time of molding. On the other hand, when alumina vapor deposition is used, ruled lines are formed or cracks occur during molding. Therefore, it is necessary to compensate for barrier degradation by laminating a barrier coating layer in addition to the vapor deposition layer. Moreover, in the case of a silica vapor deposition film, such barrier deterioration is reduced, but the cost is high.

  The vapor deposition layer in the barrier layer 14 is preferably directed to the paper side. In addition, when a vapor deposition layer is made into the content side, an aromatic component etc. will accumulate easily in the barrier layer 14, and a delamination etc. may be produced.

  The innermost layer 15 is made of a thermosetting resin, is laminated on the barrier layer 14, is in contact with the contents of the paper container, and is heated and bonded to the outermost layer 11 at the end portion of the laminated body 10. It is done. The innermost layer 15 can be heat sealed with high leakage without leaking after assembling the laminated body 10 into a paper container and filling the contents, and at the same time, the fragrance of the contents as a layer in contact with the contents It is required that it is difficult to adsorb etc. The innermost layer 15 may be composed of a plurality of layers.

As the thermosetting resin, polyethylene is mainly used, and low density polyethylene (LDPE), specifically high-pressure ethylene homopolymer, or ethylene and propylene, butene, pentene, hexene, octene, 4-methylpentene- A linear low-density polyethylene that is a copolymer with an α-olefin other than ethylene such as 1 is preferably used. As the thermoplastic resin, it is preferable to use an ethylene / α-olefin copolymer polymerized using a single-site catalyst. By using this resin, the sealing temperature can be lowered, so that the thermal pinhole is not easily formed. Become. The density of the thermoplastic resin is not particularly limited, but is usually about 0.88 to 0.920 g / cm ³ , and its melt index M.I. I. Although it is not specifically limited, Usually, it is about 0.2-20.

  The layer not in contact with the contents when the innermost layer 15 is composed of two or more layers is usually made of low-density polyethylene (LDPE) or linear low-density polyethylene (LLDPE), such as a high-pressure ethylene homopolymer, or A linear low density polyethylene which is a copolymer of ethylene and an α-olefin other than ethylene such as propylene, butene, pentene, hexene, octene and 4-methylpentene-1 is preferably used.

  Although the thickness of the innermost layer 15 will not be specifically limited if it is the range which has the above-mentioned function, Usually, it shall be about 30-100 micrometers as a whole. When the innermost layer 15 is formed of two layers, the inner layer has a thickness of about 5 to 20 μm, and the outer layer has a thickness of about 25 to 95 μm. In addition, about a layer of an inner surface side, since a slip will worsen when a metallocene type linear low density polyethylene is used, it is preferable to add a slip agent (organic type, inorganic type). In particular, an inorganic silica slip agent is preferably used as the slip agent. When this silica-based slip agent is used, the thickness of the inner surface side layer is preferably 5 to 10 μm in order to precipitate silica on the surface.

  The innermost layer 15 is melted at 220 to 350 ° C. and is extrusion coated. However, when the innermost layer 15 is composed of two or more layers, a film laminated by coextrusion so as to be in a predetermined order may be used. The coextruded film is formed by coextrusion by, for example, a T die or an inflation method.

The innermost layer 15 and the barrier layer 14 of the coextruded film are laminated by sand lamination using a thermoplastic resin such as polyethylene, or by dry lamination using an adhesive such as an ester anchor coating agent. At this time, the surface of the barrier layer 14 and the innermost layer 15 is preferably subjected to surface treatment such as corona treatment, flame treatment, ozone treatment, and anchor coat treatment. When a layer made of an adhesive or the like is formed between the innermost layer 15 and the barrier layer 14, the coating amount of the adhesive or the like is about 0.1 to 10 g / m ² .

  Although the thickness of the laminated body 10 which consists of these layer structures is also not specifically limited, Usually, it is about 250-800 micrometers.

  The method for producing a paper container according to the present invention includes a laminate in which at least an outermost layer 11 made of a thermoplastic resin, a base material layer 12 made of a paper base material, a barrier layer 14 and an innermost layer 15 made of a thermoplastic resin are sequentially laminated. A paper container made of 10 is produced including a step of forming a barrier layer 14 in which a thin film 14a is formed by vapor deposition in a state where two or more kinds of inorganic oxides are mixed on the surface of the plastic film 14b. Production of a paper container using the laminate 10 is usually performed as follows. That is, after printing on the outer surface of the sheet of the laminate 10 having the above-described layer configuration, punching and skiving and hemming the end surface so that the contents do not contact the end surface, the bottom and top portions in the filling device Heat seal by hot air heating, flame heating, etc. to make a paper container.

  The shape of the paper container may be appropriately determined according to the use and purpose, and examples thereof include a gable top type, a brick type, a flat type, and a cylindrical paper can such as a rectangular container or a round shape. Etc. For example, a polyethylene cap, a pull tab-type opening mechanism, and the like may be appropriately provided at the spout of the paper container.

  The contents of the paper container are not particularly limited, and various articles such as various foods and drinks, chemicals such as adhesives and pressure-sensitive adhesives, miscellaneous goods such as cosmetics and pharmaceuticals, and the like can be used as the contents. In addition, the paper containers are filled with various liquid foods and drinks such as curry, stew, soup, and other liquid seasonings such as juices such as liquor and fruit juices, mineral water, soy sauce, sauces and soups. It is useful as a packaging container for packaging.

(Example)
A low density polyethylene resin (density: 0.923 g / cm ³ , melt index MI; 3.7) was extrusion coated on one side of a milk base paper weighing 400 g / m ² to form an outermost layer having a thickness of 20 μm. Formed.

Next, as a barrier layer, a polyethylene terephthalate (PET) film vapor-deposited in a binary system of 12 μm thick silicon oxide (SiO ₂ ) and aluminum oxide (Al ₃ O ₂ ) (in addition, silica aluminum deposited layer 300 Å (angstrom)) , A PET film of about 12 μm, and a ratio of aluminum oxide in the vapor deposition layer of 20% by mass), the silica aluminum vapor deposition layer is subjected to in-line corona treatment, and the other surface of the milk base paper is subjected to frame treatment to obtain aluminum vapor deposition. The layer and the base milk were faced. Then, EMAA resin (M0 DuPont Polychemical Co., Ltd., N0908C) is extrusion coated at a thickness of 20 μm between the aluminum vapor deposition layer and the milk base paper, and the milk base paper and the barrier layer are bonded together by sandwich lamination as an adhesive layer. It was.

Furthermore, a low-density polyethylene resin (density: 0.923 g / cm ³ , melt index MI; 3.7) is extrusion coated on the barrier layer side bonded to the milk base paper, and an intermediate polyethylene having a thickness of 20 μm. A co-extruded film (thickness: 40 μm, outer: inner = 30 μm: 10 μm, DNP Techno Film Co., Ltd.), forming a layer and having a linear low density polyethylene resin as an outer layer and a metallocene linear low density polyethylene resin as an innermost layer Manufactured, model number: DYS-01N) was bonded together by sandwich lamination.

In this way, a laminate was produced in which PE 20 μm / paper 400 g / m ² / EMAA ²⁰ μm / (aluminum silica vapor deposition layer 300 mm / PET approximately 12 μm total 12 μm) / PE 20 μm / (LLDPE 30 μm / metallocene LLDPE 10 μm total 40 μm). .

  According to the shape of the 85 square 1.8L gable top type liquid paper container, a crease is engraved vertically, horizontally or diagonally from this laminate and punched to produce a blank plate having an adhesive margin. did. Subsequently, in order to prevent permeation of contents, liquid leakage, and the like on the end face of the blank plate manufactured as described above, a skive hemming treatment was performed to perform end face treatment. Next, hot air treatment is performed on the adhesive margin, the low-density polyethylene film of the adhesive margin is melted, and the other end of the blank plate is overlaid on the molten surface, and the two are bonded together. A cylinder-sealed seal portion was formed to form a cylindrical sleeve, and a paper container was produced. This is the paper container of Example 1.

(Example 2)
A paper container of Example 2 was produced in the same manner as in Example 1 except that the proportion of aluminum oxide in the silica aluminum vapor deposition layer was 40% by mass.

(Comparative Example 1)
A paper container of Comparative Example 1 was produced in the same manner as in Example 1 except that the ratio of aluminum oxide in the silica aluminum vapor deposition layer was 100% by mass, that is, only the aluminum oxide vapor deposition layer was used.

(Evaluation methods)
The barrier properties were evaluated for the paper containers of each Example and Comparative Example. The barrier property was determined by placing a ruled line in the laminate and forming a paper container, and then measuring oxygen permeability (per container) under the conditions of a temperature of 23 ° C. and a humidity of 90% RH using a measuring machine manufactured by MOCON. Of oxygen barrier property). The barrier property of the above-mentioned 85 square 1.8 L container was measured. Table 1 shows the oxygen permeability at this time. As shown in Table 1, in the paper container of Comparative Example 1, the barrier layer was broken by ruled lines and the like, resulting in poor oxygen barrier properties.

It is sectional drawing which shows an example of the layer structure of the laminated body which forms the paper container of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Laminated body 11 Outermost layer 12 Base material layer 13 Adhesive layer 14 Barrier layer 14a Deposition layer 14b Film 15 Innermost layer

Claims (7)

A paper container comprising a laminate in which at least an outermost layer made of a thermoplastic resin, a base material layer made of a paper base material, a barrier layer, and an innermost layer made of a thermoplastic resin are sequentially laminated,
The paper container, wherein the barrier layer is formed by forming a thin film made of two or more kinds of inorganic oxides on the surface of a plastic film.   The paper container according to claim 1, wherein the thin film made of an inorganic oxide is a thin film containing at least silicon oxide and aluminum oxide.   The paper container according to claim 2, wherein the thin film made of the inorganic oxide is deposited by mixing the silicon oxide and the aluminum oxide.   The paper container according to any one of claims 1 to 3, wherein the plastic film is biaxially stretched polyethylene terephthalate or nylon.   5. The paper container according to claim 1, wherein the innermost layer is made of an ethylene / α-olefin copolymer polymerized using a single site catalyst.   The paper container according to any one of claims 1 to 5, further comprising an adhesive layer between the base material layer and the barrier layer. At least an outermost layer made of a thermoplastic resin, a base material layer made of a paper base material, a barrier layer, an innermost layer made of a thermoplastic resin, and a method for producing a paper container comprising a laminate,
A method for producing a paper container, wherein the barrier layer is formed by vapor deposition in a state where two or more kinds of inorganic oxides are mixed on the surface of a plastic film.

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