JP2020069803A - Gas barrier laminate - Google Patents

Abstract

To provide a gas barrier laminate excellent in water vapor barrier properties and gas barrier properties.SOLUTION: A gas barrier laminate has a water vapor barrier layer and a gas barrier layer in this order on at least one surface of a paper support. The water vapor barrier layer contains a layered inorganic compound, a cationic resin, and an anionic binder. The layered inorganic compound has an aspect ratio of 80 or more and a thickness of 100 nm or less. The content of the layered inorganic compound is 0.1-800 pts.mass based on 100 pts.mass of the anionic binder. The surface charge of the cationic resin is 0.1-5.0 meq/g. The gas barrier layer contains a water-soluble polymer.SELECTED DRAWING: None

Description

  The present invention relates to a gas barrier laminate having paper as a support.

  Packaging materials that use paper as a base material and have water vapor barrier properties and gas barrier properties (particularly oxygen barrier properties) have been used to prevent deterioration of the contents of food, medical products, electronic parts, etc. Have been used since.

  As a method of imparting a water vapor barrier property or a gas barrier property to a paper base material, a method of laminating a synthetic resin film or a metal foil having excellent gas barrier properties on paper as a support is generally used. However, a material obtained by laminating a synthetic resin film or the like on a paper base material has a problem in terms of environment because it is difficult to recycle the paper, the synthetic resin and the like after use.

  Therefore, development of a gas barrier material using paper as a base material has been promoted without using a synthetic resin film or the like. For example, Patent Document 1 discloses a paper barrier material in which a water vapor barrier layer and a gas barrier layer are provided in this order on a paper base material. The water vapor barrier layer contains a water vapor barrier resin and a water repellent, and the gas barrier layer contains a water-soluble polymer and a surfactant.

  Further, Patent Document 2 discloses a paper barrier packaging material in which a water vapor barrier layer and a gas barrier layer are provided on a paper base material. The water vapor barrier layer contains kaolin having an average particle size of 5 μm or more and an aspect ratio of 10 or more in an amount of 50 to 100% by weight based on all pigments, and the binder resin of the gas barrier layer is a polyvinyl alcohol resin.

Japanese Patent No. 6234654 Japanese Patent No. 5331265

  However, since the water vapor barrier layer of the paper barrier material described in Patent Document 1 contains a water repellent agent, a uniform coating layer is formed when the gas barrier layer is coated on the water vapor barrier layer. There was a concern that it would be difficult to form. Further, the paper barrier material described in Patent Document 2 has room for improvement in the water vapor barrier property due to the existence form of kaolin in the water vapor barrier layer.

  The present invention has been made in view of the above situation. That is, an object of the present invention is to provide a gas barrier laminate having excellent water vapor barrier properties and gas barrier properties.

  The present inventors have examined the kind and shape of the layered inorganic compound in the water vapor barrier layer, and found that using a layered inorganic compound having an aspect ratio of 50 or more is effective for developing the water vapor barrier property. Found. It was also found that the addition of a cationic resin to the water vapor barrier layer improves the coatability and internal structure of the water vapor barrier layer. The present invention has been completed based on these findings. That is, the present invention has the following configurations.

(1) A gas barrier laminate having a water vapor barrier layer and a gas barrier layer in this order on at least one surface of a paper support, wherein the water vapor barrier layer contains a layered inorganic compound, a cationic resin and an anionic binder. The aspect ratio of the layered inorganic compound is 80 or more, the thickness of the layered inorganic compound is 100 nm or less, and the content of the layered inorganic compound is 0.1 to 800 with respect to 100 parts by mass of the anionic binder. Parts by mass, the surface charge of the cationic resin is 0.1 to 5.0 meq / g, and the gas barrier layer contains a water-soluble polymer.

(2) In the above (1), the anionic binder is at least one selected from the group consisting of styrene / butadiene copolymers, styrene / acrylic copolymers, and olefin / unsaturated carboxylic acid copolymers. The gas barrier laminate described.

(3) The gas barrier laminate according to (1) or (2) above, wherein the water-soluble polymer is polyvinyl alcohol or modified polyvinyl alcohol.

(4) The gas barrier laminate according to any one of (1) to (3), wherein the gas barrier layer contains the layered inorganic compound.

(5) The gas barrier laminate according to any one of (1) to (4), wherein the layered inorganic compound is at least one selected from the group consisting of mica, bentonite and kaolin.

(6) The gas barrier laminate according to any one of (1) to (5), further including a sealant layer on at least one outermost layer.

(7) The gas barrier laminate according to (6), wherein the sealant layer contains a biodegradable resin.

(8) The gas barrier laminate according to any one of (1) to (7), which is a packaging material.

  The gas barrier laminate of the present invention has excellent water vapor barrier properties and gas barrier properties.

  Hereinafter, embodiments of the present invention will be specifically described. The description of the constituent requirements described below may be made based on typical embodiments or specific examples, but the present invention is not limited to such embodiments. In addition, in this specification, the numerical range represented using "-" means the range which includes the numerical value described before and after "-" as a lower limit and an upper limit.

The gas barrier laminate of this embodiment has a water vapor barrier layer and a gas barrier layer in this order on at least one surface of the paper support. The water vapor barrier layer and the gas barrier layer may be provided on only one side of the paper support, or the water vapor barrier layer and the gas barrier layer may be provided on both sides of the paper support.
Hereinafter, each layer constituting the gas barrier laminate of the present embodiment will be described.

[Paper support]
The paper support used in the present embodiment is not particularly limited as long as it is a paper that is generally used with plant-derived pulp as a main component. Specific examples include bleached or unbleached kraft paper, high-quality paper, paperboard, liner paper, coated paper, single-glossy paper, glassine paper, and graphane paper. It is preferable that the paper mainly contains pulp that is easily dispersed in water by the mechanical disaggregation action.

  The disaggregation freeness (freeness) of the paper support measured in accordance with JIS P8121: 2012 is preferably 800 ml or less, more preferably 500 ml or less, from the viewpoint of improving the barrier property. Here, the disintegration freeness is the Canadian standard freeness (Canadian standard freeness) measured in accordance with JIS P8121: 2012 for the pulp disaggregated from the paper after paper making in accordance with JIS P8220-1. .. A known method can be used as a method for beating pulp to prepare the disintegration freeness.

The basis weight of the paper support is not particularly limited, it is preferably ^{20~400g / m 2, 30~320g / m} 2 is more preferable.

  The sizing degree of the paper support is not particularly limited, but from the viewpoint of improving the barrier property, it is preferable that the Steckigt sizing degree according to JIS P 8122: 2004 is 1 second or more. The sizing degree of the paper support is rosin-based, alkyl ketene dimer-based, alkenyl succinic anhydride-based, styrene-acrylic-based, higher fatty acid-based, petroleum resin-based, etc. It can be controlled by smoothing processing or the like. The content of the internally added sizing agent is not particularly limited, but is preferably in the range of about 0 to 3 parts by mass with respect to 100 parts by mass of pulp of the paper support.

  Known internal additives can be appropriately added to the paper support. Examples of the internal additives include fillers such as titanium dioxide, kaolin, talc and calcium carbonate, paper strength enhancers, retention improvers, pH adjusters, drainage improvers, water resistance agents, softeners, antistatic agents, Examples include defoaming agents, slime control agents, dyes and pigments, and the like.

[Water vapor barrier layer]
The water vapor barrier layer is a layer having a function of preventing the permeation of water vapor, and contains a layered inorganic compound, a cationic resin and an anionic binder.

(Layered inorganic compound)
The morphology of the layered inorganic compound is flat. When a mixed solution of a layered inorganic compound and a binder is prepared and coated on a paper support, a water vapor barrier layer is formed. In the water vapor barrier layer, the plate-like layered inorganic compounds are arranged in a state of being laminated substantially parallel to the plane (surface) of the paper support. Then, the area in which the layered inorganic compound does not exist in the planar direction becomes small, so that the permeation of water vapor is suppressed. Further, in the thickness direction, since the plate-like layered inorganic compound is arranged parallel to the plane of the paper support, the water vapor in the layer permeates the layered inorganic compound while circumventing the layered inorganic compound. Suppressed. As a result, the water vapor barrier layer can exhibit an excellent water vapor barrier property.

  The layered inorganic compound preferably has an average length of 1 μm to 100 μm. When the average length is 1 μm or more, the layered inorganic compound in the coating layer is likely to be arranged parallel to the paper support. Further, when the average length is 100 μm or less, there is little concern that part of the layered inorganic compound will protrude from the water vapor barrier layer.

  The layered inorganic compound has an aspect ratio of 50 or more. In other words, the aspect ratio is 50 or larger than 50. When the aspect ratio is 50 or more, it becomes possible to achieve a predetermined water vapor permeability. The aspect ratio of the layered inorganic compound is preferably 80 or more, more preferably 300 or more, and particularly preferably 500 or more. The larger the aspect ratio, the more the permeation of water vapor is suppressed and the water vapor barrier property is improved. Further, the larger the aspect ratio, the more the amount of the layered inorganic compound added can be reduced. The upper limit of the aspect ratio is not particularly limited, and is preferably about 10,000 or less from the viewpoint of the viscosity of the coating liquid. Here, the aspect ratio is an average value of values obtained by dividing the length of the layered inorganic compound by its thickness when a microscopic enlarged photograph of a cross section of the water vapor barrier layer is taken.

  The layered inorganic compound has a thickness of 200 nm or less. In other words, the thickness is 200 nm or smaller than 200 nm. Here, the thickness of the layered inorganic compound is an average thickness of a water vapor barrier layer when a microscopic enlarged photograph of its cross section is taken. The thickness of the layered inorganic compound is preferably 100 nm or less, more preferably 50 nm or less. The smaller the average thickness of the layered inorganic compound, the larger the number of layers of the layered inorganic compound in the water vapor barrier layer, and thus the higher water vapor barrier property can be exhibited.

  Specific examples of the layered inorganic compound include mica such as mica and brittle mica, bentonite, kaolinite (kaolin mineral), pyrophyllite, talc, smectite, vermiculite, chlorite, septe chlorite, serpentine, stilp Examples include nomelene and montmorillonite.

  Of these, at least one selected from the group consisting of mica, bentonite, and kaolin is preferable, and mica or bentonite is more preferable, from the viewpoint of improving barrier properties. Mica includes synthetic mica, muscovite (mascobite), sericite (sericite), phlogopite, biotite, fluorophlogopite (artificial mica), red mica, soda mica, vanadine mica, Examples include illite, chimica, paragonite, and brittle mica. Bentonite may be montmorillonite.

  The content of the layered inorganic compound is preferably 80% by mass or less, more preferably 70% by mass or less, further preferably 30% by mass or less, particularly preferably 20% by mass or less, based on the total solid content of the water vapor barrier layer, particularly preferably 10% by mass. The following are the most preferable. On the other hand, the content of the layered inorganic compound is preferably 1% by mass or more, and more preferably 2% by mass or more. In the present embodiment, the content of the layered inorganic compound can be reduced by increasing the aspect ratio and reducing the thickness of the layered inorganic compound. Further, the strength of the water vapor barrier layer can be increased to prevent the layered inorganic compound from falling off the water vapor barrier layer. In particular, when a layered inorganic compound having a large aspect ratio and a small thickness in a specific range, that is, a layered inorganic compound having an aspect ratio of 80 or more and a thickness of 100 nm or less is used, a microscopic enlarged photograph of the water vapor barrier layer is obtained. When taken, it clearly forms a dense film with no voids, unlike in the past. The dense film structure without voids of the water vapor barrier layer forms a tough film and effectively suppresses breakage. Further, it also contributes to the formation of a uniform gas barrier layer by suppressing the permeation of the coating liquid of the gas barrier layer.

  The content of the layered inorganic compound is 0.1 to 800 parts by mass with respect to 100 parts by mass of the anionic binder in the water vapor barrier layer. The content of the layered inorganic compound is preferably 1 to 400 parts by mass, more preferably 1 to 200 parts by mass, and further preferably 1 to 100 parts by mass with respect to 100 parts by mass of the anionic binder in the water vapor barrier layer. Parts by mass, particularly preferably 1 to 50 parts by mass, most preferably 1 to 20 parts by mass. When the content of the layered inorganic compound is 0.1 parts by mass or more based on 100 parts by mass of the anionic binder in the water vapor barrier layer, the water vapor barrier property is easily exhibited. Further, when the content of the layered inorganic compound is 800 parts by mass or less with respect to 100 parts by mass of the anionic binder in the water vapor barrier layer, a part of the layered inorganic compound is exposed from the layer surface to reduce the water vapor barrier property. Such concerns are reduced. In addition, the applicability of the gas barrier layer is reduced, a uniform gas barrier layer is not formed, and the concern that the gas barrier property is reduced is reduced.

(Cationic resin)
The present inventors have found that the addition of a cationic resin to a water vapor barrier layer containing a layered inorganic compound significantly improves the water vapor barrier property.

  The reason why the water vapor barrier property is greatly improved by adding the cationic resin is considered as follows. It is known that the layered inorganic compound has a so-called card house structure in which the flattened planar portion is easily anionic and the edge portion is cationically charged, and thus the layered inorganic compounds are three-dimensionally aggregated with each other. There is. Due to this card house structure, the aqueous dispersion of the layered inorganic compound has a very high viscosity. On the other hand, since the card house structure is easily broken when a force is applied by stirring or the like, the aqueous dispersion of the layered inorganic compound exhibits thixotropic properties.

  When a suitable cationic resin is added to the layered inorganic compound, the cationic resin is adsorbed by the anionic flat portion of the layered inorganic compound, thereby destroying the card house structure. As a result, it is presumed that the layered inorganic compound is suppressed from agglomerating three-dimensionally, the plate-shaped layered inorganic compound is easily laminated in parallel to the plane of the paper support, and leads to the improvement of the water vapor barrier property. There is.

  Specific examples of the cationic resin include polyalkylene polyamine, polyamide compound, polyamide amine-epihalohydrin or formaldehyde condensation reaction product, polyamine-epihalohydrin or formaldehyde condensation reaction product, polyamide polyurea-epihalohydrin or formaldehyde condensation reaction product, polyamine. Polyurea-epihalohydrin or formaldehyde condensation reaction product, polyamidoamine polyurea-epihalohydrin or formaldehyde condensation reaction product, polyamide polyurea compound, polyamine polyurea compound, polyamidoamine polyurea compound and polyamidoamine compound, polyethyleneimine, polyvinylpyridine, Amino-modified acrylamide compounds, polyvinylamine, polydiallyldimethylammonium Or the like can be mentioned Rorido.

  The surface charge of the cationic resin is preferably 0.1 to 10 meq / g, and more preferably 0.1 to 5.0 meq / g. When the surface charge of the cationic resin is within the above range, the card house structure can be destroyed, and the cationic resin can coexist appropriately with the anionic binder described later. The surface charge of the cationic resin is measured by the method described below.

  A polymer as a sample is dissolved in water to obtain a solution having a polymer concentration of 1 ppm. To the solution, 0.001N sodium polyethylene sulfonate is added dropwise using a charge analyzer Mutek PCD-04 type (manufactured by BTG) to measure the charge amount.

  The content of the cationic resin may be appropriately selected according to the type of the layered inorganic compound and the anionic binder used in the water vapor barrier layer, but from the viewpoint of improving the barrier property, it is based on 100 parts by mass of the layered inorganic compound. 1 to 300 parts by mass, more preferably 1 to 250 parts by mass, further preferably 10 to 150 parts by mass, particularly preferably 20 to 150 parts by mass, most preferably 20 to 100 parts by mass.

  In addition, the content of the cationic resin is preferably 0.1 to 20 parts by mass, more preferably 0.1 to 15 parts by mass, with respect to 100 parts by mass of the anionic binder of the water vapor barrier layer. It is more preferably 1 to 10 parts by mass.

(Anionic binder)
The present inventors have further found that the water vapor barrier property is further improved when the binder exhibits an anionic property. As described above, the plane portion of the layered inorganic compound is anionic, but the surface becomes cationic when the cationic resin is adsorbed. Therefore, the affinity with the anionic binder is increased.

  The anionic binder is preferably a binder modified with a monomer containing a carboxylic acid group. As the polymer serving as the skeleton of the anionic binder, a styrene / butadiene copolymer, a styrene / acrylic copolymer, a methacrylate / butadiene copolymer, an acrylonitrile / butadiene copolymer, an olefin / unsaturated carboxylic acid Examples thereof include copolymers and acrylic ester polymers. Among these, styrene / butadiene copolymers, styrene / acrylic copolymers and olefin / unsaturated carboxylic acids have good water resistance, good elongation, and are resistant to cracking of the coating layer due to breakage. It is preferably at least one selected from the group consisting of acid copolymers.

  The styrene-butadiene copolymer is an aromatic vinyl compound such as styrene, α-methylstyrene, vinyltoluene, pt-butylstyrene, chlorostyrene, 1,3-butadiene, isoprene, 2,3-dimethyl-1. , A 3-butadiene, a conjugated diene compound such as 1,3-pentadiene, and a copolymer obtained by emulsion-polymerizing a monomer composed of another compound copolymerizable therewith. Styrene is suitable as the aromatic vinyl compound, and 1,3-butadiene is suitable as the conjugated diene compound.

  Styrene / acrylic copolymers include aromatic vinyl compounds such as styrene, α-methylstyrene, vinyltoluene, pt-butylstyrene, and chlorostyrene, and acrylic acid, methacrylic acid, crotonic acid, cinnamic acid, and itacone. Unsaturated carboxylic acids having at least one carboxyl group, such as acids, fumaric acid, maleic acid, butenetricarboxylic acid and the like, itaconic acid monoethyl ester, fumaric acid monobutyl ester and maleic acid monobutyl ester Unsaturated sulfonic acid monomers such as alkyl esters, acrylamide propane sulfonic acid, acrylic acid sulfoethyl sodium salt, and methacrylic acid sulfopropyl sodium salt, or salts thereof, and monomers composed of other compounds copolymerizable therewith are used. By emulsion polymerization Resulting copolymers. Styrene or the like is preferable as the aromatic vinyl compound, and acrylic acid, methacrylic acid, itaconic acid, fumaric acid or the like is preferable as the unsaturated carboxylic acid monomer, the unsaturated sulfonic acid monomer or a salt thereof. ..

  Olefin / unsaturated carboxylic acid copolymers include olefins, especially α-olefins such as ethylene and propylene and acrylic acid, methacrylic acid, crotonic acid, cinnamic acid, itaconic acid, fumaric acid, maleic acid, butenetricarboxylic acid. Unsaturated polycarboxylic acid alkyl ester having at least one carboxyl group such as unsaturated carboxylic acid such as itaconic acid monoethyl ester, fumaric acid monobutyl ester and maleic acid monobutyl ester, acrylamidopropanesulfonic acid, acrylic acid Copolymers obtained by emulsion-polymerizing unsaturated sulfonic acid monomers such as sulfoethyl sodium salt and sulfopropyl sodium methacrylate salt or salts thereof, and monomers consisting of other compounds copolymerizable therewith Is. As the olefin, α-olefin, particularly ethylene and the like are preferable, and as the unsaturated carboxylic acid monomer, the unsaturated sulfonic acid monomer or a salt thereof, acrylic acid, methacrylic acid, itaconic acid, fumaric acid, etc. Is preferred. As a specific example of the olefin / unsaturated carboxylic acid-based copolymer, for example, an aqueous dispersion of an ethylene / acrylic acid copolymer ammonium salt is SIXEN (registered trademark) AC or the like (copolymerization ratio of acrylic acid 20%, Sumitomo It is commercially available as Seika Co., Ltd. and can be easily obtained and used.

  Specific examples of other copolymerizable compounds include cyano group-containing ethylenically unsaturated compounds, glycidyl ethers of ethylenically unsaturated acids, glycidyl ethers of unsaturated alcohols, and (meth) acrylamide compounds.

  The anionic binder can be obtained by copolymerizing the above-mentioned skeleton polymer with a monomer having a carboxylic acid group and modifying it. The copolymerization ratio of the carboxylic acid group-containing monomer is preferably 1 to 50 mol%.

  The weight average molecular weight of the anionic binder is preferably 10,000 to 10,000,000, more preferably 100,000 to 5,000,000, from the viewpoint of the viscosity of the coating liquid.

  The content ratio of the anionic binder is not particularly limited, but is preferably 20% by mass or more, more preferably 50% by mass or more, further preferably 60% by mass or more, particularly preferably 70% by mass or more based on the total solid content of the water vapor barrier layer. 80 mass% or more is the most preferable.

  The water vapor barrier layer contains, in addition to the layered inorganic compound, the cationic resin and the anionic binder, a dispersant, a surfactant, an antifoaming agent, a wetting agent, a dye, a color adjusting agent, a thickener, etc., as necessary. It is possible to add.

The thickness of the water vapor barrier layer is preferably 1 to 30 μm, more preferably 3 to 20 μm. Further, the coating amount of the water vapor barrier layer as a solid content, is preferably from 1 to 30 g / ^{m 2,} more preferably 3 to 20 g / ^{m 2.}

[Gas barrier layer]
The gas barrier layer is a layer mainly having a function of blocking permeation of oxygen gas, and contains a water-soluble polymer.

(Water-soluble polymer)
Examples of the water-soluble polymer include polyvinyl alcohol, modified polyvinyl alcohol, starch and its derivatives, cellulose derivatives, polyvinylpyrrolidone, urethane resins, polyacrylic acid and its salts, casein, polyethyleneimine, and the like.

  Among these, completely saponified or partially saponified polyvinyl alcohol or modified polyvinyl alcohol is preferable because it has more excellent gas barrier properties. Examples of the modified polyvinyl alcohol include ethylene modified polyvinyl alcohol, carboxy modified polyvinyl alcohol, silicon modified polyvinyl alcohol, acetoacetyl modified polyvinyl alcohol, diacetone modified polyvinyl alcohol and the like.

  The content of the water-soluble polymer is preferably 50 to 100% by mass and more preferably 70 to 100% by mass based on the total solid content of the gas barrier layer.

  Like the water vapor barrier layer, the gas barrier layer may contain the layered inorganic compound described above. When the layered inorganic compound is contained in the gas barrier layer, the content of the layered inorganic compound is not particularly limited, but is preferably about 1 to 20 parts by mass, and 5 to 15 parts by mass with respect to 100 parts by mass of the water-soluble polymer in the gas barrier layer. The mass part is more preferable. The layered inorganic compound is preferably at least one selected from the group consisting of mica, bentonite and kaolin from the viewpoint of improving the barrier property. The layered inorganic compound contained in the gas barrier layer may be the same kind as the layered inorganic compound contained in the water vapor barrier layer, or may be a different kind.

  In the gas barrier layer, in addition to the water-soluble polymer and the layered inorganic compound, a pigment, a dispersant, a surfactant, an antifoaming agent, a wetting agent, a dye, a color adjusting agent, a thickener, etc. are appropriately added as necessary. It is possible. The gas barrier layer may contain a layered inorganic compound by appropriately selecting it from those that can be used in the water vapor barrier layer.

The thickness of the gas barrier layer is preferably 0.1 to 10 μm, more preferably 0.5 to 5 μm. Further, the coating amount of the gas barrier layer is preferably 0.1 to 10 g / m ² as solid content, and more preferably 0.5 to 5 g / m ² .

[Gas barrier laminate]
(Production method)
The gas barrier laminate is formed by first applying a coating solution for forming a water vapor barrier layer on a paper support to form a water vapor barrier layer, and then applying a coating solution for forming a gas barrier layer to form a gas barrier layer. Can be manufactured by forming. Each layer may be formed by sequentially coating and drying a coating liquid, or may be formed by simultaneous multilayer coating and then drying.

  The solvent of the coating liquid is not particularly limited, and water or an organic solvent such as ethanol, isopropyl alcohol, methyl ethyl ketone or toluene can be used.

  The coating equipment for coating the coating liquid on the paper support is not particularly limited, and known equipment can be used. Examples of the coating equipment include a blade coater, a bar coater, an air knife coater, a slit die coater, a gravure coater, a microgravure coater, and a gate roll coater. In particular, for forming the water vapor barrier layer, a coater such as a blade coater, a bar coater, an air knife coater, or a slit die coater that scrapes the coated surface is preferable because it promotes the orientation of the layered inorganic compound.

  The drying equipment for drying the coating layer is not particularly limited, and known equipment can be used. Examples of the drying equipment include a hot air dryer, an infrared dryer, a gas burner, and a hot plate.

[Sealant layer]
The gas barrier laminate has a water vapor barrier layer and a gas barrier layer in this order on at least one surface of the paper support, and further, a sealant layer is formed on at least one outermost layer of the gas barrier laminate. May be. That is, the sealant layer may be formed on the gas barrier layer on which the water vapor barrier layer and the gas barrier layer are formed, or on the paper support on which the water vapor barrier layer and the gas barrier layer are not formed. May be formed, or may be formed on both.

  The sealant layer is a layer that is melted and bonded by heating or ultrasonic waves, and is a layer that can bond the gas barrier laminates to each other by heat sealing or the like.

  The sealant layer can be formed by laminating a synthetic resin such as polyethylene, polypropylene, an ethylene / vinyl acetate polymer, or a polyvinyl acetate polymer by a melt extrusion laminating method or a dry laminating method. The sealant layer can also be formed by applying an emulsion dispersion liquid of a synthetic resin such as polyethylene, polypropylene, an ethylene / vinyl acetate polymer, or a polyvinyl acetate polymer.

  The sealant layer preferably contains a biodegradable resin. Specific examples of the biodegradable resin are not particularly limited, and examples thereof include polylactic acid (PLA). Polybutylene succinate (PBS) Polybutylene succinate adipate (PBSA), 3-hydroxybutanoic acid-3-hydroxyhexanoic acid copolymer (PHBH) and the like can be mentioned.

The thickness of the sealant layer is preferably 1 to 50 μm, more preferably 3 to 30 μm. The amount of the sealant layer formed is preferably 1 to 50 g / m ² as solid content, and more preferably 3 to 30 g / m ² .

  The gas barrier laminate of the present embodiment, since the water vapor barrier layer contains a layered inorganic compound, a cationic resin and an anionic binder, the layered inorganic compound in the water vapor barrier layer does not form a card house structure, Since they are laminated in a state of being uniformly dispersed, they have excellent water vapor barrier properties. Furthermore, since the surface of the water vapor barrier layer is formed smooth, it is possible to uniformly form the gas barrier layer thereon, which is excellent in gas barrier properties.

  The gas barrier laminate of the present embodiment can be suitably used as a packaging material for foods, medical products, electronic parts, etc. by utilizing the above excellent water vapor barrier property and gas barrier property. Further, the gas barrier laminate of the present embodiment has resistance to breakage, and thus can be suitably used as a soft packaging material.

  Hereinafter, the gas barrier laminate of the present invention will be described more specifically with reference to Examples, but the present invention is not limited thereto. In addition, "part" and "%" in an Example and a comparative example respectively show a "mass part" and "mass%" unless there is particular notice.

The raw materials used in Examples and Comparative Examples are as follows.
(1) Paper support Bleached kraft paper: basis weight 70 g / m ² , thickness 100 μm
(2) Layered inorganic compound Mica: Swellable mica, particle size 6.3 μm, aspect ratio about 1000, thickness about 5 nm, solid content 6%, product name: NTO-05, manufactured by Topy Industries, Ltd. bentonite: swellable bentonite, Particle size 300 nm, aspect ratio 300, thickness about 1 nm, solid content 100%, product name: Kunipia F, Kunimine Industry Co., Ltd. Kaolin: Engineered Kaolin, particle size 9.0 μm, aspect ratio 80-100, thickness about 0 1 μm, solid content 100%, product name: Varisurf HX, manufactured by Imerys Minerals Phlogopite: particle size 20 μm, aspect ratio 20 to 30, thickness about 1 μm, solid content 100%, product name: AB32, Yamaguchi Co., Ltd. Mica Industry (3) Cationic resin Modified polyamide resin: Solid content 53%, Product name: SPI203 (50), Taoka Chemical Industry Co., Ltd., table Charge 0.4meq / g
(4) Anionic binder Acid-modified SBR latex: solid content 47.3%, product name: LX407S12, manufactured by ZEON CORPORATION Acid-modified SBR latex: solid content 50.5%, product name: LX407BP-6, manufactured by ZEON CORPORATION Styrene acrylic resin emulsion: solid content 53.8%, product name: Harville C-3, Dai-Ichi Paint Co., Ltd. olefin / unsaturated carboxylic acid resin emulsion: solid content 29.0%, product name: Saixen AC, Sumitomo Seika Chemical Co., Ltd. (5) Water-soluble polymer Polyvinyl alcohol: Completely saponified polyvinyl alcohol, Product name: Poval PVA 117, Kuraray Co., Ltd. (6) Sealant Low density polyethylene: LDPE, Product name: Suntec L4490, Asahi Kasei Corporation Company-made polylactic acid film: PLA, product name: Ecologue, Mitsubishi Chemical Corporation Company made polybutylene succinate: PBS, product name: Bio PBS FZ71, Mitsubishi Chemical Co., Ltd.

(Example 1)
To 47.3 parts of an aqueous dispersion of a layered inorganic compound (swelling mica, NTO-05), 90.0 parts of acid-modified SBR latex (LX407S12) and an acid-modified SBR latex (LX407BP-6) as an anionic binder with stirring. 9.4 parts was added and stirred. To this, 4.5 parts of modified polyamide resin (SPI203 (50)) as a cationic resin was added and stirred. Furthermore, 0.6 part of 25% aqueous ammonia solution was added and stirred. Further, dilution water was added to adjust the solid content concentration to 32% to obtain a coating solution for the water vapor barrier layer.
An aqueous solution of polyvinyl alcohol (PVA, Poval PVA117) having a solid content concentration of 10% was prepared as a water-soluble polymer, and used as a coating liquid for a gas barrier layer.

The resulting coating solution for the water vapor barrier layer was coated on one side of the bleached kraft paper with a Mayer bar so that the amount of the water vapor barrier layer applied after drying was 13 g / m ^2, and then hot air was applied. It was dried in a dryer at 120 ° C for 1 minute to form a water vapor barrier layer. Furthermore, after coating the coating liquid for the gas barrier layer on the water vapor barrier layer with a Mayer bar so that the coating amount after drying the gas barrier layer would be 2.0 g / m ² , 120 in a hot air dryer. It was dried at 1 ° C. for 1 minute to form a gas barrier layer to obtain a gas barrier laminate. The coating amount was adjusted by the solid content concentration of the coating liquid and the number of the Mayer bar.

(Example 2)
A gas barrier laminate was obtained in the same manner as in Example 1 except that the amount of the modified polyamide resin added was changed to 0.1 part.

(Example 3)
A gas barrier laminate was obtained in the same manner as in Example 1 except that the amount of the modified polyamide resin added was changed to 3.8 parts.

(Example 4)
A gas barrier laminate was obtained in the same manner as in Example 1 except that the amount of the modified polyamide resin added was changed to 11.3 parts.

(Example 5)
A gas barrier laminate was obtained in the same manner as in Example 1 except that the amount of the modified polyamide resin added was changed to 15.1 parts.

(Example 6)
Gas barrier laminate in the same manner as in Example 1 except that 47.3 parts of the aqueous dispersion of the layered inorganic compound (swellable mica, NTO-05) was changed to 12 parts of bentonite (swellable bentonite, Kunipia F). Got

(Example 7)
A gas barrier laminate was obtained in the same manner as in Example 1 except that 47.3 parts of the aqueous dispersion of the layered inorganic compound (swelling mica, NTO-05) was changed to 20 parts of kaolin (Varisurf HX).

(Example 8)
90.0 parts of the acid-modified SBR latex (LX407S12) and 9.4 parts of the acid-modified SBR latex (LX407BP-6) of the coating solution for the water vapor barrier layer, and 87.9 parts of a styrene acrylic resin emulsion (Herville C-3). A gas barrier laminate was obtained in the same manner as in Example 1 except that the above was changed to.

(Example 9)
A gas barrier laminate was obtained in the same manner as in Example 8 except that the amount of the modified polyamide resin added was changed to 0.1 part.

(Example 10)
A gas barrier laminate was obtained in the same manner as in Example 8 except that the amount of the modified polyamide resin added was changed to 3.8 parts.

(Example 11)
A gas barrier laminate was obtained in the same manner as in Example 8 except that the amount of the modified polyamide resin added was changed to 11.3 parts.

(Example 12)
A gas barrier laminate was obtained in the same manner as in Example 8 except that the amount of the modified polyamide resin added was changed to 15.1 parts.

(Example 13)
Gas barrier laminate in the same manner as in Example 8 except that 47.3 parts of the aqueous dispersion of the layered inorganic compound (swellable mica, NTO-05) was changed to 12 parts of bentonite (swellable bentonite, Kunipia F). Got

(Example 14)
A gas barrier laminate was obtained in the same manner as in Example 8 except that 47.3 parts of the aqueous dispersion of the layered inorganic compound (swelling mica, NTO-05) was changed to 20 parts of kaolin (Varisurf HX).

(Example 15)
90 parts of the acid-modified SBR latex (LX407S12) and 9.4 parts of the acid-modified SBR latex (LX407BP-6) of the coating liquid for the water vapor barrier layer, and 162.0 parts of an olefin / unsaturated carboxylic acid resin emulsion (Zyksen AC) A gas barrier laminate was obtained in the same manner as in Example 1 except that the above was changed to.

(Example 16)
Except for adding a step of laminating a sealant layer with a thickness of 30 μm by extrusion lamination using low density polyethylene (LDPE) as a laminating method on both surfaces of a gas barrier laminate having a water vapor barrier layer and an oxygen barrier layer. A gas barrier laminate was obtained in the same manner as in Example 8.

(Example 17)
A gas barrier laminate was obtained in the same manner as in Example 16 except that the laminating method was changed to dry laminating using a polylactic acid (PLA) film, and the laminating surface was changed to only the gas barrier layer side.

(Example 18)
A gas barrier laminate was obtained in the same manner as in Example 16 except that polybutylene succinate (PBS) was used instead of low density polyethylene as the resin used for the laminate.

(Example 19)
Example except that 87.9 parts of the styrene-acrylic resin emulsion (Harville C-3) of the coating liquid for the water vapor barrier layer was changed to 162.0 parts of the olefin / unsaturated carboxylic acid resin emulsion (Zyksen AC). A gas barrier laminate was obtained in the same manner as in 17.

(Example 20)
As a water-soluble polymer, 335 parts of an aqueous solution of polyvinyl alcohol (PVA, Poval PVA117) having a solid content concentration of 12% instead of 10%, an aqueous dispersion of a layered inorganic compound (swelling mica, NTO-05) 66.7 parts A gas barrier laminate was obtained in the same manner as in Example 1 except that a composition comprising 40 parts of water and 40 parts of water was mixed to prepare a coating solution for the gas barrier layer.

(Example 21)
As a water-soluble polymer, 335 parts of an aqueous solution of polyvinyl alcohol (PVA, Poval PVA117) having a solid content concentration of 12% instead of 10%, an aqueous dispersion of a layered inorganic compound (swelling mica, NTO-05) 66.7 parts A gas barrier laminate was obtained in the same manner as in Example 8 except that a composition comprising 40 parts of water and 40 parts of water was mixed to obtain a coating solution for the gas barrier layer.

(Example 22)
As a water-soluble polymer, 335 parts of an aqueous solution of polyvinyl alcohol (PVA, Poval PVA117) having a solid content concentration of 12% instead of 10%, an aqueous dispersion of a layered inorganic compound (swelling mica, NTO-05) 66.7 parts A gas barrier laminate was obtained in the same manner as in Example 15, except that a composition comprising 40 parts of water and 40 parts of water was mixed to form a coating solution for the gas barrier layer.

(Example 23)
As a water-soluble polymer, 335 parts of an aqueous solution of polyvinyl alcohol (PVA, Poval PVA117) having a solid content concentration of 12% instead of 10%, an aqueous dispersion of a layered inorganic compound (swelling mica, NTO-05) 66.7 parts A gas barrier laminate was obtained in the same manner as in Example 17, except that the composition comprising 40 parts of water and 40 parts of water was mixed to prepare a coating solution for the gas barrier layer.

(Example 24)
335 parts of an aqueous solution of polyvinyl alcohol (PVA, Poval PVA117) as a water-soluble polymer in which the solid concentration is 12% instead of 10%, and an aqueous dispersion of a layered inorganic compound (swelling mica, NTO-05) 35.0 parts A gas barrier laminate was obtained in the same manner as in Example 1 except that a composition comprising 40 parts of water and 40 parts of water was mixed to prepare a coating solution for the gas barrier layer.

(Example 25)
335 parts of an aqueous solution of polyvinyl alcohol (PVA, Poval PVA117) as a water-soluble polymer in which the solid concentration is 12% instead of 10%, and an aqueous dispersion of a layered inorganic compound (swelling mica, NTO-05) 90.0 parts A gas barrier laminate was obtained in the same manner as in Example 1 except that a composition comprising 40 parts of water and 40 parts of water was mixed to prepare a coating solution for the gas barrier layer.

(Example 26)
A gas barrier laminate was obtained in the same manner as in Example 15 except that 47.3 parts of the aqueous dispersion of the layered inorganic compound (swelling mica, NTO-05) was changed to 94.0 parts of kaolin (Varisurf HX). ..

(Example 27)
A gas barrier laminate was obtained in the same manner as in Example 15 except that 47.3 parts of the aqueous dispersion of the layered inorganic compound (swelling mica, NTO-05) was changed to 188.0 parts of kaolin (Varisurf HX). ..

(Example 28)
Except for adding a step of laminating a sealant layer with a thickness of 30 μm by extrusion laminating using polybutylene succinate (PBS) as a laminating method on both surfaces of a gas barrier laminate having a water vapor barrier layer and an oxygen barrier layer, A gas barrier laminate was obtained in the same manner as in Example 26.

(Comparative Example 1)
A gas barrier laminate was obtained in the same manner as in Example 1 except that the modified polyamide resin was not included in the coating liquid for the water vapor barrier layer.

(Comparative example 2)
Except that 47.3 parts of the aqueous dispersion of the layered inorganic compound (swelling mica, NTO-05) was changed to 20 parts of kaolin (Varisurf HX), and that the modified polyamide resin was not included in the coating liquid for the water vapor barrier layer. A gas barrier laminate was obtained in the same manner as in Example 1.

(Comparative example 3)
A gas barrier laminate was obtained in the same manner as in Example 8 except that the modified polyamide resin was not included in the coating liquid for the water vapor barrier layer.

(Comparative example 4)
Except that 47.3 parts of the aqueous dispersion of the layered inorganic compound (swelling mica, NTO-05) was changed to 20 parts of kaolin (Varisurf HX), and that the modified polyamide resin was not included in the coating liquid for the water vapor barrier layer. A gas barrier laminate was obtained in the same manner as in Example 8.

(Comparative example 5)
A gas barrier laminate was obtained in the same manner as in Example 8 except that 47.3 parts of the aqueous dispersion of the layered inorganic compound (swelling mica, NTO-05) was changed to 20 parts phlogopite (AB32). ..

(Comparative example 6)
Except that 47.3 parts of the aqueous dispersion of the layered inorganic compound (swelling mica, NTO-05) was changed to 20 parts of phlogopite (AB32) and that the modified polyamide resin was not included in the coating liquid for the water vapor barrier layer. A gas barrier laminate was obtained in the same manner as in Example 8.

  The water vapor barrier properties (water vapor permeability), gas barrier properties (oxygen permeability), and denseness of the obtained gas barrier laminates (Examples 16 to 19 and 28 are gas barrier laminates having a sealant layer) were evaluated. The evaluation method for each item is as shown below.

<Water vapor permeability>
According to JIS-Z-0208 (cup method) B method (40 ° C. ± 0.5 ° C., 90% ± 2% RH), the water vapor barrier layer was placed inside. The water vapor permeability of 50 g / m ² · 24 h or less is practical as a water vapor barrier layer.

<Oxygen permeability>
Using an oxygen transmission rate measuring device (OX-TRAN2 / 20, manufactured by MOCON), measurement was performed at 23 ° C. and 50% RH. When the oxygen permeability is 10 cc / m ² · 24 h or less, the gas barrier layer is practical.

<Denseness>
The cross section of the gas barrier laminate was visually observed with a microscope enlarged photograph (electron microscope photograph) and evaluated according to the following criteria. In particular, the voids in the cross-sectional photograph are discriminated as uneven brightness around the periphery, and the film structure can be strictly evaluated.
⊚: The water vapor barrier layer is uniform and highly dense, and has high barrier properties.
◯: The layered inorganic compound of the water vapor barrier layer is conspicuous, but the denseness is high and the barrier property is high.
Δ: The water vapor barrier layer has a denseness but a low barrier property.
X: The water vapor barrier layer has extremely low denseness and low barrier property.

  The evaluation results of the gas barrier laminates of Examples 1-28 and Comparative Examples 1-6 are shown in Tables 1 and 2.

  As is clear from Table 1 and Table 2, when the cationic resin was not contained, it was difficult to uniformly disperse the layered inorganic compound, and sufficient barrier performance could not be obtained (Comparative Examples 1 to 4, Comparative Example 6). Further, even when the layered inorganic compound had a large thickness and the aspect ratio was less than 50, sufficient barrier performance was not obtained (Comparative Example 5). On the other hand, when using a layered inorganic compound having a small thickness and an aspect ratio of 50 or more and containing a cationic resin, the layered inorganic compound having a high aspect ratio is uniformly dispersed, and the water vapor barrier layer is excellent in denseness, The water vapor barrier property and the gas barrier property were significantly improved (Examples 1-28).

Claims (8)

A gas barrier laminate having a water vapor barrier layer and a gas barrier layer in this order on at least one surface of a paper support,
The water vapor barrier layer contains a layered inorganic compound, a cationic resin and an anionic binder,
The aspect ratio of the layered inorganic compound is 80 or more,
The thickness of the layered inorganic compound is 100 nm or less,
The content of the layered inorganic compound is 0.1 to 800 parts by mass with respect to 100 parts by mass of the anionic binder,
The surface charge of the cationic resin is 0.1 to 5.0 meq / g,
A gas barrier laminate, wherein the gas barrier layer contains a water-soluble polymer.   The gas barrier property according to claim 1, wherein the anionic binder is at least one selected from the group consisting of styrene / butadiene copolymers, styrene / acrylic copolymers, and olefin / unsaturated carboxylic acid copolymers. Laminate.   The gas barrier laminate according to claim 1 or 2, wherein the water-soluble polymer is polyvinyl alcohol or modified polyvinyl alcohol.   The gas barrier laminate according to claim 1, wherein the gas barrier layer contains the layered inorganic compound.   The gas barrier laminate according to any one of claims 1 to 4, wherein the layered inorganic compound is at least one selected from the group consisting of mica, bentonite, and kaolin.   The gas barrier laminate according to any one of claims 1 to 5, further comprising a sealant layer on at least one outermost layer.   The gas barrier laminate according to claim 6, wherein the sealant layer contains a biodegradable resin.   The gas barrier laminate according to any one of claims 1 to 7, which is a packaging material.