JP6668576B1 - Gas barrier laminate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gas barrier laminate excellent in water vapor barrier property and gas barrier property. A gas barrier laminate having a water vapor barrier layer and a gas barrier layer on at least one surface of a paper support in this order, the water vapor barrier layer containing a layered inorganic compound, a cationic resin and an anionic binder. The aspect ratio of the layered inorganic compound is 50 or more, the thickness of the layered inorganic compound is 200 nm or less, and the content of the layered inorganic compound is 0.1 to 100 parts by mass of the anionic binder. It is 800 parts by mass, and the gas barrier layer contains a water-soluble polymer, which is a gas barrier laminate. [Selection diagram] None

Description

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

  Packaging materials that use paper as a base material and have a water vapor barrier property and a gas barrier property (particularly oxygen barrier property) have been used to prevent the deterioration of the quality of contents in the packaging of foods, medical products, electronic components, etc. Has 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 using 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 environmental aspects because it is difficult to recycle the paper or the synthetic resin after use.

  Therefore, development of a gas barrier material based on paper without using a synthetic resin film or the like has been promoted. 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.

  Patent Literature 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 diameter of 5 μm or more and an aspect ratio of 10 or more based on all pigments in an amount of 50 to 100% by weight, and the binder resin of the gas barrier layer is a polyvinyl alcohol resin.

Japanese Patent No. 6234654 Japanese Patent No. 5331265

  However, in the paper barrier material described in Patent Document 1, since the water vapor barrier layer contains a water repellent, 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 presence 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 type and shape of the layered inorganic compound in the water vapor barrier layer, and found that the use of a layered inorganic compound having an aspect ratio of 50 or more is effective for exhibiting water vapor barrier properties. Was found. Further, they have found that the addition of a cationic resin to the water vapor barrier layer improves the coating properties and internal structure of the water vapor barrier layer. The present invention has been completed based on such findings. That is, the present invention has the following configuration.

(1) A gas barrier laminate having a water vapor barrier layer and a gas barrier layer on at least one surface of a paper support in this order, 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 1 to 50 parts by mass relative to 100 parts by mass of the anionic binder. Wherein the gas barrier layer contains a water-soluble polymer.

(2) The method according to (1), wherein the anionic binder is at least one selected from the group consisting of a styrene / butadiene copolymer, a styrene / acrylic copolymer, and an olefin / unsaturated carboxylic acid copolymer. The gas barrier laminate according to the above.

(3) The gas barrier laminate according to (1) or (2), wherein the cationic resin has a surface charge of 0.1 to 10 meq / g.

(4) The gas barrier laminate according to any one of (1) to (3), wherein the water-soluble polymer is polyvinyl alcohol or modified polyvinyl alcohol.

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

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

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

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

(9) The gas barrier laminate according to any one of (1) to (8), 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 components described below may be made based on representative embodiments or specific examples, but the present invention is not limited to such embodiments. In addition, in this specification, a numerical range represented by using “to” means a range including numerical values described before and after “to” as a lower limit and an upper limit.

The gas barrier laminate of the present embodiment 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 and the gas barrier layer may be provided only on 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 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, matte paper, glassine paper, graphan paper, and the like. It is preferable that the paper is mainly composed of pulp which is easily dispersed in water by mechanical disaggregation.

  The disintegration freeness (freeness) of the paper support measured according to JIS P8121: 2012 is preferably 800 ml or less, more preferably 500 ml or less, from the viewpoint of improving barrier properties. Here, the defibration freeness refers to the Canadian standard freeness obtained by measuring the pulp obtained by disintegrating the paper after papermaking in accordance with JIS P8220-1 in accordance with JIS P8121: 2012. . A known method can be used for beating the pulp in order to adjust the disaggregation 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 Stechig sizing degree according to JIS P 8122: 2004 is 1 second or more. The sizing degree of the paper support is determined by the type and content of the internal sizing agent such as rosin type, alkyl ketene dimer type, alkenyl succinic anhydride type, styrene-acrylic type, higher fatty acid type, petroleum resin type, and pulp type. It can be controlled by a smoothing process or the like. The content of the internal sizing agent is not particularly limited, but is preferably in the range of about 0 to 3 parts by mass based on 100 parts by mass of the pulp of the paper support.

  Further, known internal additives can be appropriately added to the paper support. As internal additives, for example, fillers such as titanium dioxide, kaolin, talc, calcium carbonate, paper strength enhancer, retention enhancer, pH adjuster, drainage improver, waterproofing agent, softener, antistatic agent, Examples include an antifoaming agent, a slime control agent, and a dye / pigment.

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

(Layered inorganic compound)
The form of the layered inorganic compound is flat. When a mixed solution of a layered inorganic compound and a binder is prepared and applied 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, since the area where the layered inorganic compound is not present in the plane direction is reduced, the permeation of water vapor is suppressed. Further, in the thickness direction, since the plate-like layered inorganic compound is arranged in parallel to the plane of the paper support, the water vapor in the layer is transmitted while bypassing the layered inorganic compound, and the permeation of the water vapor is reduced. Is suppressed. As a result, the water vapor barrier layer can exhibit excellent water vapor barrier properties.

  The average length of the layered inorganic compound is preferably 1 μm to 100 μm. When the average length is 1 μm or more, the layered inorganic compound in the coating layer is easily arranged in parallel to the paper support. Further, when the average length is 100 μm or less, there is little concern that a part of the layered inorganic compound projects 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 greater. When the aspect ratio is 50 or more, a predetermined water vapor permeability can be achieved. The aspect ratio of the layered inorganic compound is preferably 80 or more, more preferably 300 or more, and particularly preferably 500 or more. As the aspect ratio is larger, the transmission of water vapor is suppressed, and the water vapor barrier property is improved. Further, the larger the aspect ratio is, 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 obtained by dividing the length of the layered inorganic compound by its thickness when a microscopic photograph of the cross section of the water vapor barrier layer is taken.

  The thickness of the layered inorganic compound is 200 nm or less. In other words, the thickness is 200 nm or smaller. Here, the thickness of the layered inorganic compound is the average thickness of a cross-section of the water vapor barrier layer when a microscopic enlarged photograph is taken. The thickness of the layered inorganic compound is preferably 100 nm or less, more preferably 50 nm or less. When the average thickness of the layered inorganic compound is smaller, the number of laminated layered inorganic compounds in the water vapor barrier layer becomes larger, so that a higher water vapor barrier property can be exhibited.

  Specific examples of the layered inorganic compound include mica, mica, brittle mica, etc., bentonite, kaolinite (kaolin mineral), pyrophyllite, talc, smectite, vermiculite, chlorite, septe chlorite, serpentine, stilp Nomelane, montmorillonite and the like can be mentioned.

  Among these, from the viewpoint of improving the barrier properties, at least one selected from the group consisting of mica, bentonite and kaolin is preferable, and mica or bentonite is more preferable. Mica includes synthetic mica, muscovite (muscovite), sericite (sericite), biotite (flokopite), biotite (biotite), fluorophlogopite (artificial mica), red mica, soda mica, vanadin mica, Illite, chimica, paragonite, brittle mica and the like. In addition, the bentonite includes 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, and more preferably 10% by mass in the total solid content of the water vapor barrier layer. The following are most preferred. On the other hand, the content of the layered inorganic compound is preferably 1% by mass or more, 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 decreasing the thickness of the layered inorganic compound. In addition, the strength of the water vapor barrier layer can be increased to prevent the layered inorganic compound from falling off from 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, an enlarged microscopic photograph of a water vapor barrier layer is obtained. When taken, the film is clearly different from the conventional one and forms a dense film without voids. The dense film structure without voids of the water vapor barrier layer forms a tough film and effectively suppresses breakage. In addition, it suppresses the penetration of the coating liquid into the gas barrier layer and contributes to the formation of a uniform gas barrier layer.

  The content of the layered inorganic compound is 0.1 to 800 parts by mass based on 100 parts by mass of the anionic binder in the water vapor barrier layer. The content of the layered inorganic compound is preferably from 1 to 400 parts by mass, more preferably from 1 to 200 parts by mass, and still more preferably from 1 to 100 parts by mass, per 100 parts by mass of the anionic binder of the water vapor barrier layer. Parts by weight, particularly preferably 1 to 50 parts by weight, most preferably 1 to 20 parts by weight. 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 of the water vapor barrier layer, the water vapor barrier property is easily developed. 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 of the water vapor barrier layer, a part of the layered inorganic compound is exposed from the layer surface and the water vapor barrier property is reduced. Such concerns are reduced. In addition, there is less concern that the coating property of the gas barrier layer is reduced and a uniform gas barrier layer is not formed, and the gas barrier property is reduced.

(Cationic resin)
The present inventors have found that by adding a cationic resin to a water vapor barrier layer containing a layered inorganic compound, the water vapor barrier properties are greatly improved.

  The reason why the water vapor barrier property is greatly improved by adding a cationic resin is considered as follows. It is known that the layered inorganic compound has a so-called card house structure in which the planar portion of the plate-like form is easily anionically charged and the edge portion is easily charged cationically, so that the layered inorganic compounds are mutually sterically aggregated. I have. 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.

  If an appropriate cationic resin is added here, the card house structure is destroyed by the adsorption of the cationic resin to the anionic plane portion of the layered inorganic compound. As a result, it is presumed that the layered inorganic compound is prevented from sterically aggregating, and the plate-shaped layered inorganic compound is easily laminated in parallel with the plane of the paper support, which leads to an improvement in water vapor barrier properties. I have.

  Specific examples of the cationic resin include polyalkylene polyamine, polyamide compound, polyamidoamine-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 compound, polyvinylamine, polydiallyldimethylammonium Or the like can be mentioned Rorido.

  The cationic resin preferably has a surface charge of 0.1 to 10 meq / g, 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 can coexist appropriately with an anionic binder described later. The surface charge of the cationic resin is measured by the method described below.

  A polymer serving as a sample is dissolved in water to obtain a solution having a polymer concentration of 1 ppm. 0.001N sodium polyethylenesulfonate is dropped into the solution using a charge analyzer Mutek PCD-04 (manufactured by BTG), and the charge amount is measured.

  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 properties, 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, still more preferably 10 to 150 parts by mass, particularly preferably 20 to 150 parts by mass, most preferably 20 to 100 parts by mass.

  Further, the content of the cationic resin is preferably 0.1 to 20 parts by mass, more preferably 0.1 to 15 parts by mass, based on 100 parts by mass of the anionic binder of the water vapor barrier layer. 1 to 10 parts by mass is more preferred.

(Anionic binder)
The present inventors have further found that the more anionic the binder, the better the water vapor barrier 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.

  As the anionic binder, a binder modified with a monomer containing a carboxylic acid group is preferable. Examples of the polymer serving as the skeleton of the anionic binder include styrene / butadiene copolymers, styrene / acrylic copolymers, methacrylate / butadiene copolymers, acrylonitrile / butadiene copolymers, and olefin / unsaturated carboxylic acids. Copolymers and acrylic ester polymers. Among them, styrene / butadiene copolymer, styrene / acrylic copolymer and olefin / unsaturated carboxylic acid are preferable because they have good water resistance, good elongation, and hardly cause cracks in the coating layer due to breaking. It is preferably at least one selected from the group consisting of acid copolymers.

  Styrene-butadiene copolymers include aromatic vinyl compounds such as styrene, α-methylstyrene, vinyltoluene, pt-butylstyrene, and chlorostyrene, and 1,3-butadiene, isoprene, and 2,3-dimethyl-1. A copolymer obtained by emulsion polymerization of a monomer comprising a conjugated diene compound such as 1,3-butadiene and 1,3-pentadiene, and other compounds copolymerizable therewith. Styrene is preferred as the aromatic vinyl compound, and 1,3-butadiene is preferred as the conjugated diene compound.

  Styrene / acrylic copolymers include aromatic vinyl compounds such as styrene, α-methylstyrene, vinyltoluene, pt-butylstyrene, chlorostyrene, acrylic acid, methacrylic acid, crotonic acid, cinnamic acid, itacone Unsaturated carboxylic acids having at least one carboxyl group such as acids, unsaturated carboxylic acids such as fumaric acid, maleic acid and butenetricarboxylic acid, monoethyl itaconate, monobutyl fumarate and monobutyl maleate; Unsaturated sulfonic acid monomers such as alkyl esters, acrylamidopropanesulfonic acid, sodium sulfoethyl acrylate, sodium sulfopropyl methacrylate or salts thereof, and monomers composed of other compounds copolymerizable therewith. By emulsion polymerization Resulting copolymers. Styrene and the like are preferable as the aromatic vinyl compound, and acrylic acid, methacrylic acid, itaconic acid and fumaric acid are preferable as the unsaturated carboxylic acid monomer and 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, and butenetricarboxylic acid. Unsaturated carboxylic acid having at least one carboxyl group, such as unsaturated carboxylic acid such as monoethyl ester of itaconic acid, monobutyl ester of fumarate and monobutyl ester of maleic acid, acrylamide propanesulfonic acid, acrylic acid Unsaturated sulfonic acid monomers such as sodium sulfoethyl salt and sodium sulfopropyl methacrylate or salts thereof, and copolymers obtained by emulsion polymerization of monomers composed of other compounds copolymerizable therewith. It is. As olefins, α-olefins, especially ethylene, are preferable, and unsaturated carboxylic acid monomers, unsaturated sulfonic acid monomers or salts thereof include acrylic acid, methacrylic acid, itaconic acid, fumaric acid, and the like. Is preferred. Specific examples of the olefin / unsaturated carboxylic acid copolymer include, for example, an aqueous dispersion of an ammonium salt of an ethylene / acrylic acid copolymer; (Manufactured by 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 a monomer having a carboxylic acid group with the polymer serving as the above skeleton and modifying the copolymer. The copolymerization ratio of the monomer containing a carboxylic acid group is preferably 1 to 50 mol%.

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

  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, still more 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. It is preferably at least 80% by mass.

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

The thickness of the water vapor barrier layer is preferably from 1 to 30 μm, more preferably from 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 preventing oxygen gas from permeating, and contains a water-soluble polymer.

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

  Among these, completely saponified or partially saponified polyvinyl alcohol or modified polyvinyl alcohol is preferred because of its better 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, and diacetone-modified polyvinyl alcohol.

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

  The gas barrier layer may contain the above-mentioned layered inorganic compound similarly to the water vapor barrier layer. 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 with respect to 100 parts by mass of the water-soluble polymer of the gas barrier layer, and 5 to 15 parts by mass. Parts by mass are more preferred. The layered inorganic compound is preferably at least one selected from the group consisting of mica, bentonite, and kaolin from the viewpoint of improving barrier properties. The layered inorganic compound contained in the gas barrier layer may be the same type as the layered inorganic compound contained in the water vapor barrier layer, or may be a different type.

  The gas barrier layer, in addition to the water-soluble polymer and the laminar inorganic compound, appropriately adds a pigment, a dispersant, a surfactant, a defoaming agent, a wetting agent, a dye, a color adjusting agent, a thickener, and the like as needed. It is possible. The gas barrier layer may contain a layered inorganic compound appropriately selected from those usable in the water vapor barrier layer.

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

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

  The solvent for 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 applying the coating liquid to 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, a coater that scrapes the coating surface such as a blade coater, a bar coater, an air knife coater, and a slit die coater is preferable for forming the water vapor barrier layer in that the orientation of the layered inorganic compound is promoted.

  The drying equipment for drying the coating layer is not particularly limited, and a 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 on at least one surface of the paper support in this order, and further has a sealant layer formed on at least one outermost layer of the gas barrier laminate. You may. That is, the sealant layer may be formed on the gas barrier layer on the side where the water vapor barrier layer and the gas barrier layer are formed, or may be formed on the paper support on the side where the water vapor barrier layer and the gas barrier layer are not formed. Or it 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 lamination method or a dry lamination method. Further, the sealant layer can also be formed by applying an emulsified dispersion 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. For example, 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 from 1 to 50 μm, and more preferably from 3 to 30 μm. Further, the formation amount of the sealant layer is preferably 1 to 50 g / m ² , more preferably 3 to 30 g / m ² , as a solid content.

  Since the gas barrier laminate of the present embodiment contains the layered inorganic compound, the cationic resin and the anionic binder in the water vapor barrier layer, 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 smoothly, the gas barrier layer thereon can be formed uniformly, and the gas barrier property is excellent.

  The gas barrier laminate of the present embodiment can be suitably used as a packaging material for foods, medical products, electronic components, etc. by utilizing the above-mentioned excellent water vapor barrier properties and gas barrier properties. In addition, the gas barrier laminate of the present embodiment can be suitably used as a soft packaging material because it has resistance to breaking.

  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 the Examples and Comparative Examples, "parts" and "%" indicate "parts by mass" and "% by mass", respectively, unless otherwise specified.

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 diameter 6.3 μm, aspect ratio about 1000, thickness about 5 nm, solid content 6%, product name: NTO-05, manufactured by Topy Industries, Inc. Bentonite: swellable bentonite, Particle size 300 nm, aspect ratio 300, thickness about 1 nm, solid content 100%, product name: Kunipia F, manufactured by Kunimine Industries Kaolin: engineered kaolin, particle diameter 9.0 μm, aspect ratio 80-100, thickness about 0 0.1 μm, solid content 100%, product name: Varisurf HX, manufactured by Imeris Minerals Co., Ltd. phlogopite: particle diameter 20 μm, aspect ratio 20-30, thickness about 1 μm, solid content 100%, product name: AB32, Yamaguchi Corporation Mica Kogyo (3) Cationic resin Modified polyamide resin: 53% solids, 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: Herville C-3, manufactured by Daiichi Paint Co., Ltd. Olefin / unsaturated carboxylic acid resin emulsion: solid content 29.0%, product name: Seixen AC, (5) Water-soluble polymer made by Sumitomo Seika Co., Ltd. Polyvinyl alcohol: completely saponified polyvinyl alcohol, product name: Poval PVA117, product made by Kuraray (6) Sealant Low density polyethylene: LDPE, product name: Suntech L4490, Asahi Kasei Corporation Company-made polylactic acid film: PLA, Product name: Ecologe, Mitsubishi Chemical Corporation Company made polybutylene succinate: PBS, product name: Bio PBS FZ71, Mitsubishi Chemical Co., Ltd.

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

The obtained coating solution for the water vapor barrier layer is coated on one surface of bleached kraft paper with a Mayer bar so that the coating amount after drying of the water vapor barrier layer is 13 g / m ^2, and then heated with hot air. It dried at 120 degreeC for 1 minute in the dryer, and formed the water vapor barrier layer. Further, the coating liquid of the gas barrier layer was applied on the water vapor barrier layer with a Mayer bar so that the coating amount after drying of the gas barrier layer was 2.0 g / m ^2, and then the coating liquid was applied in a hot air drier. C. for 1 minute to form a gas barrier layer to obtain a gas barrier laminate. The coating amount was adjusted according to the solid content concentration of the coating solution and the count 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 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 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 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 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 an aqueous dispersion of a layered inorganic compound (swellable mica, NTO-05) was changed to 12 parts of bentonite (swellable bentonite, Kunipia F). I 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 (swellable mica, NTO-05) was changed to 20 parts of kaolin (Varisurf HX).

(Example 8)
97.9 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 were mixed with 87.9 parts of a styrene acrylic resin emulsion (Hervil C-3). Except that the gas barrier laminate was obtained in the same manner as in Example 1.

(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 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 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 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 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 an aqueous dispersion of a layered inorganic compound (swellable mica, NTO-05) was changed to 12 parts of bentonite (swellable bentonite, Kunipia F). I 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 (swellable 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 were combined with 162.0 parts of an olefin / unsaturated carboxylic acid-based resin emulsion (Saixen AC). Except that the gas barrier laminate was obtained in the same manner as in Example 1.

(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 lamination method on both sides of the gas barrier laminate having the water vapor barrier layer and the oxygen barrier layer formed thereon. In the same manner as in Example 8, a gas barrier laminate was obtained.

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

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

(Example 19)
Example 8 Except that 87.9 parts of a styrene acrylic resin emulsion (Hervil C-3) as a coating liquid for a water vapor barrier layer was changed to 162.0 parts of an olefin / unsaturated carboxylic acid resin emulsion (Saixen AC). In the same manner as in Example 17, a gas barrier laminate was obtained.

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

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

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

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

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

(Example 25)
As a water-soluble polymer, 335 parts of an aqueous solution having a solid content of polyvinyl alcohol (PVA, Poval PVA117) of 12% instead of 10%, and 90.0 parts of an aqueous dispersion of a layered inorganic compound (swellable mica, NTO-05) And a composition comprising water and 40 parts of water to obtain a gas barrier layered body in the same manner as in Example 1, except that a coating solution for the gas barrier layer was obtained.

(Example 26)
A gas barrier laminate was obtained in the same manner as in Example 15, except that 47.3 parts of an aqueous dispersion of a layered inorganic compound (swellable 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 (swellable 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 to a thickness of 30 μm by extrusion lamination using polybutylene succinate (PBS) as a lamination method on both sides of a gas barrier laminate having a water vapor barrier layer and an oxygen barrier layer formed thereon. In the same manner as in Example 26, a gas barrier laminate was obtained.

(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 an aqueous dispersion of a layered inorganic compound (swellable mica, NTO-05) was changed to 20 parts of kaolin (Varisurf HX) and that the modified polyamide resin was not included in the coating solution of the water vapor barrier layer. In the same manner as in Example 1, a gas barrier laminate was obtained.

(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 an aqueous dispersion of a layered inorganic compound (swellable mica, NTO-05) was changed to 20 parts of kaolin (Varisurf HX) and that the modified polyamide resin was not included in the coating solution of the water vapor barrier layer. In the same manner as in Example 8, a gas barrier laminate was obtained.

(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 (swellable mica, NTO-05) was changed to 20 parts of phlogopite (AB32). .

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

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

<Water vapor permeability>
The measurement was performed by JIS-Z-0208 (cup method) method B (40 ° C. ± 0.5 ° C., 90% ± 2% RH) with the water vapor barrier layer inside. As the standard for water vapor transmission rate, if 50g ^/ m 2 · 24h or less, there is a practical as water vapor barrier layer.

<Oxygen permeability>
The measurement was performed under the conditions of 23 ° C. and 50% RH using an oxygen permeability measuring device (OX-TRAN 2/20, manufactured by MOCON). Incidentally, as a measure of the oxygen permeability, when 10cc ^/ m 2 · 24h or less, there is a practical as gas barrier layer.

<Denseness>
The cross section of the gas barrier laminate was visually observed with a microscope enlarged photograph (electron micrograph), and evaluated according to the following criteria. In particular, the voids in the cross-sectional photograph are discriminated as luminance unevenness in the periphery, and strict evaluation of the film structure can be performed.
A: The water vapor barrier layer is uniform and dense, and the barrier property is high.
：: 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 high density but a low barrier property.
×: The denseness of the water vapor barrier layer is extremely low, and the barrier property is low.

  Tables 1 and 2 show the evaluation results of the gas barrier laminates of Examples 1 to 28 and Comparative Examples 1 to 6.

  As is clear from Tables 1 and 2, when no cationic resin was contained, uniform dispersion of the layered inorganic compound was difficult, and sufficient barrier performance could not be obtained (Comparative Examples 1 to 4, Comparative Example 6). Also, when the thickness of the layered inorganic compound was large 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 denseness of the water vapor barrier layer is excellent, Water vapor barrier properties and gas barrier properties were significantly improved (Examples 1 to 28).

Claims (9)

A gas barrier laminate having a water vapor barrier layer and a gas barrier layer on at least one surface of a paper support in this order,
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 1 to 50 parts by mass with respect to 100 parts by mass of the anionic binder,
The 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 a styrene / butadiene copolymer, a styrene / acrylic copolymer, and an olefin / unsaturated carboxylic acid copolymer. Laminate.   The gas barrier laminate according to claim 1 or 2, wherein the cationic resin has a surface charge of 0.1 to 10 meq / g.   The gas barrier laminate according to any one of claims 1 to 3, wherein the water-soluble polymer is polyvinyl alcohol or modified polyvinyl alcohol.   The gas barrier laminate according to any one of claims 1 to 4, wherein the gas barrier layer contains the layered inorganic compound.   The gas barrier laminate according to any one of claims 1 to 5, 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 6, further comprising a sealant layer in at least one outermost layer.   The gas barrier laminate according to claim 7, wherein the sealant layer contains a biodegradable resin.   The gas barrier laminate according to any one of claims 1 to 8, which is a packaging material.