Multilayer body and paper processed article using same

Abstract

A multilayer body comprising a thermoplastic resin layer, a paper base material layer, a barrier layer, and a sealant layer, in that order, wherein the barrier layer includes a polyurethane resin, a swellable layered silicate, and a cationic resin.

Description

Laminate and paper processed product made using same

[0001] The present disclosure relates to a laminate having barrier properties, and also to a paper product made using the laminate.

[0002] Packaging materials in which gas barrier properties such as oxygen barrier properties and water vapor barrier properties have been imparted to a paper base material have conventionally been used in packaging foods, medical products, electronic components, and the like to prevent deterioration of the contents.

[0003] A common method for imparting water vapor barrier properties or gas barrier properties to a paper substrate is to laminate a synthetic resin film or the like with excellent gas barrier properties onto the paper substrate. However, materials in which a synthetic resin film or the like is laminated onto a paper substrate have environmental issues, as it is difficult to recycle the paper and synthetic resin after use.

[0004] Therefore, progress has been made in the development of gas barrier materials that use paper as a base material without using synthetic resin films, etc. For example, Patent Document 1 (JP 2021-138434 A) describes a technology for controlling the hydroxyl groups and acid groups of the resin used in the gas barrier layer in a paper barrier material in which a gas barrier layer and a heat seal layer are provided in this order on a paper base material.

[0005] The paper barrier material described in Patent Document 1 has a single barrier layer, which makes it possible to reduce the amount of plastic material. However, this is not sufficient from the perspective of achieving higher gas barrier properties or achieving both gas barrier properties and water vapor barrier properties. The present disclosure aims to provide a laminate that achieves both high levels of gas barrier properties and water vapor barrier properties and also has an improved paper ratio (biomass ratio).

[0006] The present disclosure relates to the following items <1> to <10>. <1> A laminate comprising, in this order, a thermoplastic resin layer, a paper substrate layer, a barrier layer, and a sealant layer, wherein the barrier layer contains a polyurethane resin, a swellable layered silicate, and a cationic resin. <2> The laminate according to <1>, wherein the polyurethane resin contains at least one selected from the group consisting of polyurethanes having structural units derived from metaxylylene diisocyanate and hydroxy polyurethanes. <3> The laminate according to <1> or <2>, wherein the barrier layer contains 1.0 to 20.0% by mass of the cationic resin. <4> The laminate according to any one of <1> to <3>, wherein the barrier layer contains 30.0 to 80.0% by mass of the polyurethane resin. <5> The laminate according to any one of <1> to <4>, wherein the barrier layer contains 5.0 to 30.0% by mass of the swellable layered silicate. <6> The laminate according to any one of <1> to <5>, wherein the barrier layer further comprises at least one selected from the group consisting of a water-dispersible polymer other than a polyurethane resin and a water-soluble polymer other than a polyurethane resin, wherein the water-dispersible polymer comprises an olefin-unsaturated carboxylic acid copolymer, and the water-soluble polymer comprises at least one selected from the group consisting of a vinyl alcohol polymer and a polyalkyleneimine. <7> The laminate according to any one of <1> to <6>, wherein the barrier layer further comprises a water-dispersible polymer other than the polyurethane resin and a water-soluble polymer other than the polyurethane resin, and wherein the barrier layer comprises the water-dispersible polymer and the water-soluble polymer in at least the following combination (A) or (B): (A) Water-suspendable polymer: ethylene-acrylic acid copolymer, water-soluble polymer: polyvinyl alcohol (B) Water-suspendable polymer: ethylene-acrylic acid copolymer, water-soluble polymer: polyvinyl alcohol and polyethyleneimine <8> The laminate according to <6> or <7>, wherein the barrier layer contains 2.0 to 50.0 mass% in total of the water-suspendable polymer other than the polyurethane resin and the water-soluble polymer other than the polyurethane resin.<9> The laminate according to any one of <6> to <8>, wherein the ratio of the mass of the polyurethane resin to the total mass of the water-dispersible polymer other than the polyurethane resin and the water-soluble polymer other than the polyurethane resin (mass of the polyurethane resin:total mass of the water-dispersible polymer and the water-soluble polymer) in the barrier layer is 50:50 to 95:5. <10> The laminate according to any one of <1> to <9>, which has an undercoat layer between the paper base layer and the barrier layer. <11> The laminate according to any one of <1> to <10>, wherein the sealant layer contains a water-dispersible resin. <12> A processed paper product obtained using the laminate according to any one of <1> to <11>.

[0007] In this specification, the range "X to Y" means "X or more and Y or less." When a numerical range is described in stages, the upper and lower limits of each numerical range can be combined arbitrarily. In this specification, (meth)acrylic refers collectively to acrylic and methacrylic. In this specification, unless otherwise specified, operations and measurements of physical properties, etc. are performed under conditions of room temperature (20 to 25°C) and a relative humidity of 40 to 50% RH.

[0008] One embodiment of the present disclosure is a laminate comprising a thermoplastic resin layer, a paper substrate layer, a barrier layer, and a sealant layer in this order, wherein the barrier layer contains a polyurethane resin, a swellable layered silicate, and a cationic resin.

[0009] According to this embodiment, it is possible to provide a laminate that achieves both high gas barrier properties and water vapor barrier properties and further has an improved paper ratio (biomass ratio). In this specification, "gas barrier properties" means "oxygen barrier properties" unless otherwise specified.

[0010] <Thermoplastic resin layer> The thermoplastic resin layer is a layer that becomes the outer surface (printed surface) of a paper product (e.g., a liquid paper container) when the paper product is formed, and the thermoplastic resin layer and the sealant layer are heat-sealed when the paper product is formed. The thermoplastic resin layer is a layer mainly composed of a thermoplastic resin and may contain components other than the thermoplastic resin. In this specification, the term "main component" means that the content is 50% by mass or more, preferably 80% by mass or more, or 90% by mass or more (upper limit 100% by mass). The resin used in the thermoplastic resin layer is not particularly limited as long as it can be heat-sealed to the sealant layer, but it is preferable that the resin itself has heat-sealability. Specific examples include low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), medium-density polyethylene (MDPE), high-density polyethylene (HDPE), ethylene-propylene copolymer, ethylene-butene copolymer, propylene-butene copolymer, propylene homopolymer, propylene-ethylene random copolymer, propylene-ethylene block copolymer, propylene-ethylene-butene copolymer, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, ethylene-methyl acrylate copolymer, ethylene-ethyl acrylate copolymer, ethylene-methyl methacrylate copolymer, cyclohexanedimethanol-modified polyethylene, Examples of suitable resins include polyester resins such as polyethylene terephthalate copolymer, polymethylpentene, polyethylene terephthalate (PET), polybutylene terephthalate (PBT), and polyester copolymers, polystyrene, polyvinyl chloride, acrylonitrile butadiene styrene (ABS) resin, acrylic resin, modified polyphenylene ether (PPE), and polyamide resins; and biodegradable resins such as polylactic acid (PLA), polyhydroxybutyric acid (PHB), polybutylene succinate (PBS), poly(butylene adipate-co-butylene terephthalate) (PBAT), polycaprolactone (PCL), and poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH). These may be used alone or in combination of two or more.

[0011] The method for forming the thermoplastic resin layer is not particularly limited. The thermoplastic resin layer may be formed by laminating the resin using a known method, or by coating a coating liquid in which the resin is dissolved or dispersed in a solvent. When the thermoplastic resin layer is formed by lamination, the resin used for the thermoplastic resin layer preferably comprises at least one selected from the group consisting of polyethylene and a biodegradable resin, more preferably at least one selected from the group consisting of low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), and a biodegradable resin, even more preferably at least one selected from the group consisting of low-density polyethylene (LDPE) and linear low-density polyethylene (LLDPE), and even more preferably low-density polyethylene (LDPE). Polyethylene is preferred as a liquid paper container material because of its low cost and moderate flexibility. When the thermoplastic resin layer is formed by coating, an acrylic resin is preferred as the resin used for the thermoplastic resin layer. Acrylic resins (especially acrylic copolymers) have the advantage of easily controlling physical properties such as heat sealability, printability, and film-forming properties.

[0012] As the acrylic resin, either a commercially available product or a synthetic product may be used. Examples of commercially available products include Brightone FC-640V manufactured by Sakata Inx Corporation, JONCRYL PDX7326 and JONCRYL JDX-6500 manufactured by BASF Japan Ltd., and SEIKOAT RE-2016 and SEIKOAT RE-2194 manufactured by Seiko PMC Corporation.

[0013] The weight per unit area of ​​the thermoplastic resin layer is not particularly limited, but is preferably 1 to 50 g / m ２ It is preferable that the density is 2 to 30 g / m ２ The thickness of the thermoplastic resin layer is not particularly limited, but from the viewpoint of moldability, it is preferably 5 to 100 μm, and more preferably 10 to 50 μm. The thermoplastic resin layer may be formed as a single layer of a single resin, a single layer of a mixture of multiple resins, or multiple layers of the same or different resins.

[0014] <Paper Base Layer> The paper base material used for the paper base layer is not particularly limited, and known paper materials can be used. The pulp constituting the paper base is preferably mainly composed of plant-derived pulp, and is mainly composed of wood pulp. Examples of wood pulp include hardwood pulp and softwood pulp. Examples of non-wood pulp include cotton pulp, hemp pulp, kenaf pulp, and bamboo pulp. Materials other than pulp fibers, such as synthetic fibers such as rayon fiber and nylon fiber, may also be blended as secondary paper materials as long as they do not impair the effects of the present disclosure.

[0015] Specific examples of paper substrates include bleached kraft paper, unbleached kraft paper, fine paper, paperboard, liner paper, coated paper, one-side gloss bleached kraft paper, glassine paper, graphene paper, etc. Among these, bleached kraft paper, unbleached kraft paper, fine paper, and one-side gloss bleached kraft paper are preferred. Bleached kraft paper and one-side gloss bleached paper are more preferred, and one-side gloss bleached kraft paper is even more preferred.

[0016] The paper substrate may contain additives. Examples of additives include pH adjusters (sodium bicarbonate, sodium hydroxide, etc.), dry strength agents (polyacrylamide, starch, etc.), wet strength agents (polyamide polyamine epichlorohydrin resin, melamine-formaldehyde resin, or urea-formaldehyde resin), internal sizing agents (rosin-based, alkyl ketene dimer, etc.), drainage yield aids, antifoaming agents, fillers (calcium carbonate, talc, etc.), dyes, etc. These additives may be used alone or in combination of two or more. The content of the additives is not particularly limited and may be within a commonly used range.

[0017] (Basis weight) The basis weight of the paper substrate is not particularly limited, but is usually 20 g / m ２ More than 600g / m ２ For example, for packaging bag applications, the thickness is 20 g / m ２ 150g / m or more ２ Preferably, 30 g / m or less ２ More than 100g / m ２ More preferably, 40 g / m or less ２ 70g / m or more ２Further, for applications such as liquid paper containers, paper containers, and paper cups, the thickness is preferably 150 g / m or less. ２ More than 600g / m ２ Preferably, 200 g / m or less ２ More than 400g / m ２ The following is more preferred: The basis weight of the paper substrate is measured in accordance with JIS P 8124:2011.

[0018] (Paper Thickness) The thickness of the paper substrate is not particularly limited, but is usually 20 μm or more and 1000 μm or less. For example, for packaging bag applications, it is preferably 20 μm or more and 250 μm or less, more preferably 25 μm or more and 170 μm or less, and even more preferably 30 μm or more and 100 μm or less. Furthermore, for applications such as liquid paper containers, paper containers, and paper cups, it is preferably 150 μm or more and 1000 μm or less, more preferably 200 μm or more and 650 μm or less. The thickness of the paper substrate is measured in accordance with JIS P 8118:2014.

[0019] (Oken Smoothness) The smoothness of the paper substrate is not particularly limited. For example, the Oken Smoothness of the surface on which the barrier layer is to be formed is preferably 5 seconds or more, more preferably 10 seconds or more. The upper limit is not particularly limited, but is, for example, preferably 2000 seconds or less, more preferably 1000 seconds or less. The Oken Smoothness of the paper substrate is measured in accordance with JIS P 8155:2010.

[0020] (Method for manufacturing paper base material) A method for manufacturing a paper base material includes a method of making a paper stock containing pulp. The paper stock may further contain additives. Examples of additives include the additives listed above.

[0021] The stock can be prepared by adding additives to a pulp slurry. The pulp slurry is obtained by beating pulp in the presence of water. The pulp beating method and beating device are not particularly limited and may be the same as known beating methods and beating devices. The pulp content in the stock is not particularly limited and may be within a commonly used range. For example, it is 60% by mass or more and less than 100% by mass relative to the total mass of the stock.

[0022] Papermaking from stock can be carried out by a conventional method. For example, the stock is cast onto a wire or the like, dewatered to obtain a wet paper, and multiple wet papers are stacked as necessary, and this single-layer or multi-layer wet paper is pressed and dried. In this case, if multiple wet papers are not stacked, a single-layer paper is obtained, and if multiple wet papers are stacked, a multi-layer paper is obtained. When multiple wet papers are stacked, an adhesive may be applied to the surface of the wet paper (the surface on which other wet papers are stacked).

[0023] <Barrier Layer> The barrier layer contains a polyurethane resin, a swellable layered silicate, and a cationic resin. A barrier layer having such a configuration can provide a laminate that achieves both high gas barrier properties and water vapor barrier properties and also has an improved paper ratio (biomass ratio). The barrier layer may be one layer or two or more layers, but from the perspective of production costs, a single layer (single layer) is preferred.

[0024] (Polyurethane Resin) The barrier layer contains a polyurethane resin. The polyurethane resin is not particularly limited as long as it is a polymer having a urethane bond, and known polyurethane resins can be used. From the viewpoint of achieving both higher water vapor barrier properties and gas barrier properties, the polyurethane resin preferably contains at least one selected from the group consisting of polyurethanes having structural units derived from meta-xylylene diisocyanate and hydroxy polyurethanes, and more preferably contains hydroxy polyurethanes. Polyurethane resins are generally obtained by the reaction of a polyisocyanate with a polyol having two or more hydroxy groups. "Polyurethanes having structural units derived from meta-xylylene diisocyanate" refers to polyurethane resins obtained by the above reaction using meta-xylylene diisocyanate as the polyisocyanate in part or in whole. Furthermore, "hydroxy polyurethane" refers to polyurethane resins having hydroxy groups. The hydroxy value of the hydroxy polyurethane is preferably 100 to 500 mgKOH / g, more preferably 150 to 400 mgKOH / g, and even more preferably 200 to 350 mgKOH / g. When the hydroxyl group value is within the above range, the cohesive strength of the hydroxy polyurethane increases, and the hydroxy polyurethane is more likely to exhibit high barrier properties.

[0025] The hydroxy polyurethane may have an acid group. The acid value of the hydroxy polyurethane is preferably 50 to 100 mgKOH / g, more preferably 10 to 70 mgKOH / g, and even more preferably 15 to 60 mgKOH / g. The acid value and hydroxyl value of the hydroxy polyurethane can be measured by titration in accordance with JIS K 1557:2007.

[0026] When the polyurethane resin has a metaxylylene diisocyanate-derived structural unit, the content of the metaxylylene diisocyanate-derived structural unit relative to the total amount of polyisocyanate-derived structural units is preferably 50 mol% or more. Such a polyurethane resin is thought to have better gas barrier properties because it exhibits high cohesive strength due to hydrogen bonding and the stacking effect between xylylene groups. The content is １ The identification can be performed using known analytical techniques such as H-NMR.

[0027] The glass transition temperature of the polyurethane resin is preferably 50° C. or higher, more preferably 65° C. or higher, even more preferably 90° C. or higher, and even more preferably 110° C. or higher, and the upper limit is not particularly limited, but is, for example, 200° C. or lower. The glass transition temperature of the polyurethane resin is a value measured in accordance with JIS K 7121:1987.

[0028] Commercially available hydroxy polyurethanes can be used. Examples include HPU W-001, HPU W-003, and HPU-W013A (all manufactured by Dainichiseika Color & Chemicals Mfg. Co., Ltd.). Examples of polyurethanes having structural units derived from metaxylylene diisocyanate include Takelac WPB-341(30) (manufactured by Mitsui Chemicals, Inc.).

[0029] The content of the polyurethane resin in the barrier layer is preferably 30.0 to 80.0 mass%, more preferably 40.0 to 75.0 mass%, even more preferably 50.0 to 70.0 mass%, even more preferably 55.0 to 68.0 mass%, and even more preferably 60.0 to 66.0 mass%. By being in the above range, the water vapor barrier property and gas barrier property are more easily improved. Furthermore, by being in the above range, the strength of the barrier layer is improved, and the heat sealability of the sealant layer is improved.

[0030] (Swellable layered silicate) In order to further improve the water vapor barrier property and gas barrier property, the barrier layer contains a swellable layered silicate. The morphology of the swellable layered silicate is flat. By including a swellable layered silicate in the barrier layer, the flat swellable layered silicate is easily laminated substantially parallel to the plane (surface) of the paper substrate. This reduces the area in the planar direction where the swellable layered silicate is not present, making it easier to suppress water vapor permeation. Furthermore, in the thickness direction, the flat swellable layered silicate is arranged parallel to the plane of the paper substrate, so that water vapor in the layer permeates while bypassing the swellable layered silicate, and the maze effect suppresses water vapor permeation. As a result, the barrier layer is more likely to exhibit excellent water vapor barrier property.

[0031] The average thickness of the swellable layered silicate is preferably 200 nm or less. The average thickness of the swellable layered silicate is preferably 120 nm or less, more preferably 50 nm or less, even more preferably 25 nm or less, and particularly preferably 10 nm or less. The smaller the thickness of the swellable layered silicate, the greater the number of layers of the swellable layered silicate in the barrier layer, and therefore the greater the water vapor barrier property that can be exhibited. The lower limit of the thickness of the swellable layered silicate is not particularly limited, but it is preferably 2 nm or more.

[0032] Here, the average thickness of the swellable layered silicate contained in the barrier layer is determined as follows: A magnified photograph of the cross section of the barrier layer is taken using an electron microscope. At this time, the magnification is set so that approximately 20 to 30 pieces of swellable layered silicate are included in the image. The thickness of each piece of swellable layered silicate in the image is measured. The average value of the obtained thicknesses is then calculated to be the average thickness of the swellable layered silicate.

[0033] The average length of the swellable layered silicate is preferably 1 μm or more and 100 μm or less. When the average length is 1 μm or more, the swellable layered silicate is likely to be aligned parallel to the paper substrate. Furthermore, when the average length is 100 μm or less, there is little concern that a portion of the swellable layered silicate will protrude from the barrier layer. The average length of the swellable layered silicate is more preferably 50 μm or less, even more preferably 30 μm or less, and particularly preferably 15 μm or less. Here, the average length of the swellable layered silicate contained in the barrier layer is determined as follows: A magnified photograph of the cross section of the barrier layer is taken using an electron microscope. At this time, the magnification is set so that approximately 20 to 30 swellable layered silicates are included in the image. The length (major axis) of each swellable layered silicate in the image is measured. The average value of the obtained lengths is then calculated to determine the average length of the swellable layered silicate. The length of the swellable layered silicate is sometimes expressed as a particle diameter.

[0034] The swellable layered silicate preferably has an aspect ratio of 50 or more. An aspect ratio of 50 or more makes it easier to improve the water vapor barrier property. The aspect ratio of the swellable layered silicate is preferably 80 or more, more preferably 300 or more, and particularly preferably 500 or more. The larger the aspect ratio, the more water vapor permeation is suppressed and the water vapor barrier property is improved. Furthermore, the larger the aspect ratio, the less the amount of swellable layered silicate added can be reduced. The upper limit of the aspect ratio is not particularly limited, and from the viewpoint of the viscosity of the coating liquid, it is preferably about 10,000 or less, more preferably about 5,000 or less, and even more preferably about 2,000 or less. That is, preferred ranges of the aspect ratio include 50 to 10,000, 80 to 5,000, 300 to 2,000, and 500 to 2,000. Here, the aspect ratio is, as described above, a value obtained by taking an enlarged photograph of the cross section of the barrier layer using an electron microscope and dividing the average length of the swellable layered silicate obtained by the enlarged photograph by its average thickness.

[0035] Specific examples of swellable layered silicates include micas such as mica and brittle mica, bentonite, kaolinite (kaolin mineral), pyrophyllite, talc, smectite, vermiculite, chlorite, septe chlorite, serpentine, stilpnomelane, and montmorillonite.

[0036] Among these, in particular, from the viewpoint of improving barrier properties, it is preferable to contain one or more of mica and bentonite, and mica or bentonite is more preferable. Specific examples of mica include synthetic mica (e.g., swelling mica, non-swelling mica), muscovite, sericite, phloxopite, biotite, fluorphlogopite (artificial mica), red mica, soda mica, vanadium mica, illite, zinc mica, paragonite, and brittle mica. Specific examples of bentonite include montmorillonite. These may be used alone or in combination of two or more.

[0037] Swellable layered silicates are layered inorganic compounds that swell in water and whose layers easily cleave under shear to a thickness on the order of nanometers. By combining a polyurethane resin with a swellable layered silicate, a thin, high-aspect-ratio swellable layered silicate is dispersed in a polyurethane resin film that already has high gas barrier performance, resulting in a labyrinth effect that further enhances gas barrier performance. Examples of swellable layered silicates include sodium tetrasilicic mica, sodium hectorite, lithium taeniolite, fluorphlogopite, sodium smectite, and sodium montmorillonite. The swellable layered silicate is preferably a swellable mica such as sodium tetrasilicic mica. Among commercially available swellable layered silicates, examples of swellable mica include NTO-05 (manufactured by Topy Industries) and Somasif ME300B-4T (manufactured by Katakura Co-op Agri Co., Ltd.).

[0038] The content of the swellable layered silicate in the barrier layer is preferably 5.0 to 30.0 mass%, more preferably 10.0 to 25.0 mass%, and even more preferably 13.0 to 24.0 mass%. By keeping it within this range, the water vapor barrier property and gas barrier property can be more easily improved.

[0039] (Cationic Resin) The barrier layer contains a cationic resin in addition to the polyurethane resin and the swellable layered silicate. The combined use of a flat inorganic compound and a cationic resin significantly improves gas barrier and water vapor barrier properties, particularly water vapor barrier properties. Swellable layered silicates tend to have anionic particle surfaces and cationic particle end faces, leading to the surface and end faces attracting each other and forming a house-of-cards aggregation structure. Addition of a cationic resin can sequester the anionic groups on the particle surfaces with cations, disrupting the house-of-cards aggregation structure. This suppresses steric aggregation of the swellable layered silicate, allowing the swellable layered silicate to align parallel to the plane of the paper substrate, fully demonstrating the maze effect. As a result, extremely high gas barrier and water vapor barrier properties can be achieved.

[0040] Specific examples of the cationic resin include polyamide compounds, modified polyamide compounds, polyamine compounds, modified polyamine compounds, polyamidoamine-epihalohydrin or formaldehyde condensation reaction products, polyamine-epihalohydrin or formaldehyde condensation reaction products, polyamidepolyurea-epihalohydrin or formaldehyde condensation reaction products, polyaminepolyurea-epihalohydrin or formaldehyde condensation reaction products, polyamidoaminepolyurea-epihalohydrin or formaldehyde condensation reaction products, polyamidepolyurea compounds, polyaminepolyurea compounds, polyamidoaminepolyurea compounds, polyvinylpyridine, amino-modified acrylamide compounds, polyvinylamine, polydiallyldimethylammonium chloride, etc. Among these, the cationic resin is preferably a modified polyamide compound, and more preferably a modified polyamide resin. As the modified polyamide resin, commercially available products may be used, for example, SPI203(50)H manufactured by Taoka Chemical Co., Ltd.

[0041] The content of the cationic resin in the barrier layer may be selected appropriately depending on the type of material used in the barrier layer, such as polyurethane resin, swellable layered silicate, etc. From the viewpoint of further improving the barrier property (particularly the water vapor barrier property) and / or the heat sealability, the content of the cationic resin in the barrier layer is preferably 1.0 to 20.0 mass%, more preferably 1.0 to 10.0 mass%, even more preferably 1.5 to 8.0 mass%, still more preferably 1.8 to 5.0 mass%, and particularly preferably 2.0 to 4.5 mass%.

[0042] The surface charge of the cationic resin is preferably 0.1 to 10 meq / g, more preferably 0.1 to 5.0 meq / g, even more preferably 0.1 to 4.0 meq / g, even more preferably 0.1 to 2.0 meq / g, and particularly preferably 0.2 to 1.0 meq / g. When the surface charge of the cationic resin is equal to or greater than the lower limit, the effect of adding the cationic resin is more fully obtained. On the other hand, when the surface charge is equal to or less than the upper limit, the effect of the cationic resin can be more fully exerted while suppressing aggregation of the swellable layered silicate. The surface charge of the cationic resin is measured by the method described below. First, a sample polymer is dissolved in water to obtain a solution with a polymer concentration of 1 ppm. 0.001 N sodium polyethylene sulfonate is added dropwise to the solution using a charge analyzer Mutek PCD-04 (manufactured by BTG Corporation), and the charge amount is measured.

[0043] (Water-Suspendable Polymer, Water-Soluble Polymer) The barrier layer may contain other resins in addition to the polyurethane resin to the extent that the above-mentioned effects are not impaired. The other resins are not particularly limited, but examples thereof include polyolefin resins (polyethylene, polypropylene, etc.), vinyl chloride resins, styrene resins, styrene / butadiene copolymers, acrylonitrile / styrene copolymers, acrylonitrile / butadiene copolymers, ABS resins, AAS resins, AES resins, vinylidene chloride resins, polyurethane resins, poly-4-methylpentene-1 resins, polybutene-1 resins, vinylidene fluoride resins, vinyl fluoride resins, fluororesins, polycarbonate resins, acetal resins, polyphenylene oxide resins, polyester resins (polyethylene terephthalate, polybutylene terephthalate, etc.), polyphenylene sulfide resins, polyimide resins, polysulfone resins, polyethersulfone resins, aromatic polyester resins, polyarylate resins, olefin / unsaturated carboxylic acid copolymers, styrene / unsaturated carboxylic acid copolymers, acrylic resins, polyvinyl alcohol and modified resins thereof, polyacrylic acid and salts thereof, polysaccharide resins such as cellulose derivatives, starch and derivatives thereof, natural rubber, naturally derived thermosetting resins such as shellac, and modified products thereof. These may be used alone or in combination of two or more.

[0044] The water-dispersible polymer other than the polyurethane resin preferably includes at least one selected from the group consisting of a styrene-butadiene copolymer, a styrene / acrylic copolymer, an olefin-unsaturated carboxylic acid copolymer, and a polyolefin resin, and more preferably includes an olefin-unsaturated carboxylic acid copolymer. The water-dispersible polymer may be used alone or in combination of two or more.

[0045] The water-soluble polymer other than the polyurethane resin preferably includes at least one selected from the group consisting of a vinyl alcohol polymer, a polyalkyleneimine, a (meth)acrylic acid polymer, a polyethylene glycol, a polyacrylamide, a polycarboxylic acid, and a water-soluble cellulose derivative, and more preferably includes at least one selected from the group consisting of a vinyl alcohol polymer and a polyalkyleneimine. When the barrier layer contains a polyalkyleneimine, the effect of improving adhesion to the sealant layer is also obtained. The water-soluble polymer may be used alone or in combination of two or more.

[0046]

[0003] Studies by the present inventors have revealed that although the three components of polyurethane resin, flat inorganic compound, and cationic resin are good in terms of barrier properties, they are insufficient in terms of film-forming properties of the barrier layer. The present inventors have therefore discovered that the film-forming properties of the barrier layer are improved by using a water-dispersible polymer or a water-soluble polymer in addition to the three components of polyurethane resin, flat inorganic compound, and cationic resin, and as a result, the water vapor barrier property and gas barrier property are improved. Hereinafter, water-dispersible polymers and water-soluble polymers other than polyurethane resins are collectively referred to as film-forming aids.

[0047] When forming a barrier layer by aqueous coating, water-soluble polymers are more effective at improving film-forming properties than water-dispersible polymers. Furthermore, from the viewpoint of improving the water resistance of the barrier layer and further improving the water vapor barrier properties, it is preferable to use a water-dispersible polymer in addition to a water-soluble polymer. That is, the barrier layer preferably contains a water-dispersible polymer and a water-soluble polymer. In this case, the water-dispersible polymer preferably contains an olefin-unsaturated carboxylic acid copolymer, more preferably an ethylene-(meth)acrylic acid copolymer. Furthermore, the water-soluble polymer preferably contains a vinyl alcohol polymer, more preferably polyvinyl alcohol. The mass ratio of the content of the water-dispersible polymer to the content of the water-soluble polymer in the barrier layer (water-dispersible polymer:water-soluble polymer) is preferably 20:1 to 1:2, more preferably 10:1 to 2:3, even more preferably 5:1 to 3:4, and even more preferably 4:1 to 4:5.

[0048] When a water-dispersible polymer and a water-soluble polymer are used in combination, it is preferable to use, for example, a combination of an ethylene-acrylic acid copolymer as the water-dispersible polymer and polyvinyl alcohol as the water-soluble polymer. In this case, other water-dispersible polymers and / or water-soluble polymers, such as polyethyleneimine, may also be used in combination. That is, the barrier layer preferably contains a water-dispersible polymer and a water-soluble polymer, and in this case, it is preferable to contain the water-dispersible polymer and the water-soluble polymer in at least the following combination (A) or (B): (A) Water-dispersible polymer: ethylene-acrylic acid copolymer, water-soluble polymer: polyvinyl alcohol (B) Water-dispersible polymer: ethylene-acrylic acid copolymer, water-soluble polymer: polyvinyl alcohol and polyethyleneimine

[0049] (Water-Suspendable Polymer) <<Styrene / Butadiene Copolymer>> Styrene-butadiene copolymers are copolymers obtained by emulsion polymerization of monomers consisting of styrene compounds such as styrene, α-methylstyrene, vinyltoluene, p-t-butylstyrene, and chlorostyrene, butadiene compounds such as 1,3-butadiene, isoprene (2-methyl-1,3-butadiene), 2,3-dimethyl-1,3-butadiene, and 1,3-pentadiene, as well as other compounds copolymerizable with these. Styrene is preferred as the styrene compound, and 1,3-butadiene is preferred as the butadiene compound.

[0050] As the styrene-butadiene copolymer, commercially available products can also be used, for example, LX407S12 (manufactured by Nippon Zeon Co., Ltd.) as an acid-modified styrene-butadiene copolymer binder.

[0051] Styrene / Acrylic Copolymers Styrene / acrylic copolymers are copolymers obtained by emulsion polymerization of monomers consisting of styrene compounds such as styrene, α-methylstyrene, vinyltoluene, p-t-butylstyrene, and chlorostyrene, acrylic compounds such as acrylic acid, methacrylic acid, (meth)acrylic acid esters, (meth)acrylamidopropanesulfonic acid, and (meth)acrylic acid sulfoalkyl sodium salts (the alkyl group has 2 to 3 carbon atoms), and other compounds copolymerizable therewith. Styrene is preferred as the styrene compound, and acrylic acid, methacrylic acid, acrylic acid esters, and methacrylic acid esters are preferred as the acrylic compound, with acrylic acid and acrylic acid esters being more preferred. As the (meth)acrylic acid ester, alkyl acrylate esters are preferred, and the alkyl group preferably has 1 to 6 carbon atoms.

[0052] As the styrene / acrylic copolymer, commercially available products can also be used, for example, JONCRYL HSL-9012 (manufactured by BASF) as a styrene-acrylic copolymer binder.

[0053] <Olefin / Unsaturated Carboxylic Acid Copolymer> The olefin / unsaturated carboxylic acid copolymer is a copolymer obtainable by emulsion polymerization of a monomer consisting of an olefin, particularly an α-olefin such as propylene, or ethylene, and an unsaturated carboxylic acid such as acrylic acid, methacrylic acid, crotonic acid, cinnamic acid, itaconic acid, fumaric acid, maleic acid, or butenetricarboxylic acid, an unsaturated polycarboxylic acid alkyl ester having at least one carboxy group such as itaconic acid monoethyl ester, fumaric acid monobutyl ester, or maleic acid monobutyl ester, or another compound copolymerizable therewith.

[0054] The olefin is preferably ethylene or an α-olefin, more preferably ethylene. Furthermore, the unsaturated carboxylic acid monomer is preferably acrylic acid, methacrylic acid, itaconic acid, fumaric acid, or the like. The olefin / unsaturated carboxylic acid copolymer is preferably an ethylene-(meth)acrylic acid copolymer, more preferably an ethylene-acrylic acid copolymer.

[0055] As a specific example of the olefin / unsaturated carboxylic acid copolymer, for example, an aqueous dispersion of an ammonium salt of an ethylene-acrylic acid copolymer is commercially available under the trade name ZAIXXEN (registered trademark) AC (copolymerization ratio of acrylic acid: 20%, manufactured by Sumitomo Seika Chemicals Co., Ltd.), and can be easily obtained and used.

[0056] <Polyolefin Resin> The polyolefin resin is preferably a homopolymer or copolymer of a monomer selected from the group consisting of ethylene and α-olefins, and more preferably polyethylene. Commercially available polyolefins can also be used. For example, an example of a polyolefin resin binder is HYDRECT HS (manufactured by DIC Corporation).

[0057] (Water-soluble polymer) <<Vinyl alcohol polymer>> Examples of vinyl alcohol polymers include polyvinyl alcohol. The polyvinyl alcohol preferably has a saponification degree of 85.0 to 99.5 mol%, more preferably 90.0 to 99.0 mol%. Commercially available polyvinyl alcohols can also be used. Examples include the EXCEVAL series (manufactured by Kuraray Co., Ltd.).

[0058] <Polyalkyleneimine> From the viewpoint of adhesion to the sealant layer, the polyalkyleneimine is preferably a polyalkyleneimine having an alkylene group with 1 to 5 carbon atoms, and polyethyleneimine is preferred. The polyethyleneimine may be a linear polyethyleneimine or a branched polyethyleneimine. The weight-average molecular weight is also not particularly limited, but is preferably 300 to 1,000,000, and more preferably 1,000 to 100,000.

[0059] <(Meth)acrylic Acid Polymer> Examples of the (meth)acrylic acid polymer include polyacrylic acid, polymethacrylic acid, and salts thereof. Examples of the salt include sodium poly(meth)acrylate and ammonium poly(meth)acrylate. Commercially available (meth)acrylic acid polymers can also be used. For example, an aqueous solution of ammonium polyacrylate can be Aron A-30 (manufactured by Toagosei Co., Ltd.).

[0060] <Polyethylene Glycol> Polyethylene glycols having any degree of polymerization and weight-average molecular weight can be used, but the weight-average molecular weight range is preferably from 60,000 to 250,000, and more preferably from 100,000 to 170,000. The weight-average molecular weight is a value measured by gel permeation chromatography (standard substance: polystyrene). Commercially available polyethylene glycols include Alcox R-150 and R-400 manufactured by Meisei Chemical Industry Co., Ltd.

[0061] <Polyacrylamide> Any known polyacrylamide can be used as the polyacrylamide. The degree of polymerization and weight-average molecular weight of the polyacrylamide are not particularly limited.

[0062] <Polycarboxylic Acid> Examples of polycarboxylic acids include polymaleic acid, acrylic acid-maleic acid copolymer, and polyglucuronic acid.

[0063] <Water-soluble Cellulose Derivatives> Examples of water-soluble cellulose derivatives include methyl cellulose, hydroxymethyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, hydroxypropyl cellulose, methylhydroxypropyl cellulose, and methylhydroxyethyl cellulose.

[0064] The weight-average molecular weight of the water-suspendable polymer and the water-soluble polymer is preferably 10,000 or more, more preferably 20,000 or more, and preferably 10,000,000 or less, more preferably 5,000,000 or less. The weight-average molecular weight of the water-suspendable polymer is measured using gel permeation chromatography (standard: polystyrene). The weight-average molecular weight of the water-soluble polymer is measured using gel permeation chromatography (standard: polyethylene glycol).

[0065] The total content of water-suspendable polymers other than polyurethane resins and water-soluble polymers other than polyurethane resins in the barrier layer is preferably 2.0 to 50.0 mass%, more preferably 5.0 to 45.0 mass%, even more preferably 10.0 to 35.0 mass%, and even more preferably 15.0 to 25.0 mass%. Being within the above ranges makes it easier to improve the water vapor barrier property and gas barrier property. The content of water-suspendable polymers other than polyurethane resins in the barrier layer is preferably 1.0 to 40.0 mass%, more preferably 5.0 to 30.0 mass%, even more preferably 8.0 to 20.0 mass%, and even more preferably 10.0 to 18.0 mass%. Being within the above ranges makes it easier to improve the water vapor barrier property and gas barrier property. The content of the water-soluble polymer other than the polyurethane resin in the barrier layer is preferably 1.0 to 20.0 mass%, more preferably 2.0 to 15.0 mass%, even more preferably 2.0 to 10.0 mass%, and even more preferably 3.0 to 9.0 mass%. By keeping it within the above range, the water vapor barrier property and gas barrier property can be more easily improved.

[0066] From the viewpoint of achieving both barrier properties (particularly gas barrier properties) and film-forming properties, the mass ratio of the polyurethane resin to the film-forming aid in the barrier layer (polyurethane resin:film-forming aid) is preferably 50:50 to 95:5, more preferably 55:45 to 90:10, even more preferably 60:40 to 85:15, and even more preferably 65:35 to 85:15. In other words, the mass ratio of the polyurethane resin to the film-forming aid is the ratio of the mass of the polyurethane resin to the total mass of the water-dispersible polymer other than the polyurethane resin and the water-soluble polymer other than the polyurethane resin (mass of the polyurethane resin:total mass of the water-dispersible polymer other than the polyurethane resin and the water-soluble polymer other than the polyurethane resin).

[0067] The barrier layer may contain, as needed, dispersants, surfactants, antifoaming agents, wetting agents, dyes, color adjusters, thickeners, and the like, to the extent that the above-mentioned specific barrier properties are not impaired.

[0068] (Coating amount of the barrier layer) The coating amount of the barrier layer is not particularly limited, but from the viewpoint of barrier properties, it is preferably 1 g / m as a solid content after drying. ２ More preferably, 2 g / m ２ From the viewpoint of redisintegration, it is preferably 15 g / m ２ More preferably, it is 10 g / m or less. ２ More preferably, 8 g / m or less ２ and even more preferably 6 g / m or less. ２ That is, the preferred range of the coating amount of the barrier layer is 1 g / m or less. ２ 15g / m or more ２ Below, 1g / m ２ 10g / m or more ２ Below, 2g / m ２ 8g / m or more ２ and 2 g / m ２ 6g / m or more ２ The thickness of the barrier layer is preferably 1 to 20 μm, and more preferably 2 to 10 μm.

[0069] (Method for forming a barrier layer) The method for forming the barrier layer is not particularly limited. For example, a coating liquid for a barrier layer is prepared by dispersing in a solvent at least one resin selected from the group consisting of water-dispersible polymers and water-soluble polymers other than polyurethane resins, a polyurethane resin, a swellable layered silicate, and a cationic resin. The obtained coating liquid for a barrier layer is preferably applied to a paper substrate and dried to form a barrier layer.

[0070] The solvent for the barrier layer coating liquid is not particularly limited, and may be water or an organic solvent such as ethanol, isopropyl alcohol, methyl ethyl ketone, or toluene. Among these, an aqueous medium is preferred, and water is more preferred, as the dispersion medium for the barrier layer coating liquid, from the viewpoint of avoiding the problems associated with volatile organic solvents. In this specification, an aqueous medium refers to a medium containing 50% by mass or more of water.

[0071] The device used for applying the barrier layer coating solution is not particularly limited, and may be appropriately selected from commonly used coating devices, such as an air knife coater, blade coater, gravure coater, rod blade coater, roll coater, reverse roll coater, Mayer bar coater, curtain coater, die slot coater, champlex coater, metering blade type size press coater, short dwell coater, spray coater, gate roll coater, and lip coater.

[0072] <Sealant Layer> The sealant layer of this embodiment is a layer that becomes the inner surface (liquid-contacting surface) of a paper product (e.g., a liquid paper container) when the paper product is formed, and the thermoplastic resin layer and the sealant layer are heat-sealed when the paper product is formed. The sealant layer is a layer that melts and adheres by heating, ultrasonic waves, etc. The sealant layer is not particularly limited as long as it has heat-sealing properties, and known resins that have heat-sealing properties can be used. The sealant layer is a layer whose main component is a resin that has heat-sealing properties, and may contain components other than the resin that has heat-sealing properties (e.g., wax, pigment, etc.).

[0073] The method for forming the sealant layer is not particularly limited, and the sealant layer may be formed by laminating a resin having heat-sealing properties using a known method, or the sealant layer may be formed by preparing a sealant layer coating liquid in which a resin having heat-sealing properties is dissolved or dispersed in a solvent, coating the sealant layer on the barrier layer, and drying the liquid.

[0074] The sealant layer may be formed by laminating an adhesive layer on one side of a heat-sealable resin film and then bonding the adhesive layer and the barrier layer together by dry lamination, or by applying a heat-sealable resin to the sealant layer by extrusion lamination without using an adhesive. In the case of dry lamination, aging may be performed. Note that the extrusion lamination method may result in a decrease in oxygen barrier properties due to the influence of heat during extrusion, so the dry lamination method is preferred.

[0075] When forming a sealant layer by lamination, the heat-sealable resin is preferably at least one selected from the group consisting of polyethylene, polyester resin, and biodegradable resin, more preferably at least one selected from the group consisting of low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), polyester resin, and biodegradable resin, and even more preferably at least one selected from the group consisting of low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), and polyester resin. The adhesive layer is not particularly limited, and any known adhesive that can be used for lamination can be used. Commercially available adhesives may be used, such as DIC Dry LX-500 / K W-75 (urethane adhesive) and PASLIM VM001 / 108CP (gas barrier urethane adhesive) manufactured by DIC Corporation, and MAXIVE M-100 (gas barrier epoxy adhesive) manufactured by Mitsubishi Gas Chemical Company, Inc.

[0076] The resin film having heat-sealability may be a vapor-deposited film. That is, the laminate of the present embodiment may further include a vapor-deposited layer. The vapor-deposited layer may be a vapor-deposited layer of a metal such as aluminum, or may be a vapor-deposited layer of an inorganic oxide such as silica or alumina. The vapor-deposited layer may be formed by a known method such as a vacuum deposition method or a sputtering method.

[0077] When a sealant layer is formed by lamination, the thickness of the sealant layer is not particularly limited, but is preferably 10 μm or more, more preferably 15 μm or more, from the viewpoint of heat sealing properties, and is preferably 75 μm or less, more preferably 50 μm or less, from the viewpoint of reducing environmental load. That is, when a sealant layer is formed by lamination, preferred ranges for the thickness of the sealant layer include 10 μm or more and 75 μm or less, and 15 μm or more and 50 μm or less. In addition, the basis weight is not particularly limited, but is preferably 10 g / m from the viewpoint of heat sealing properties. ２ More preferably, 15 g / m ２ From the viewpoint of reducing the environmental load, it is preferably 75 g / m２ or less, more preferably 50 g / m ２ That is, the preferred range of the basis weight of the sealant layer is 10 g / m or less. ２ 75g / m or more ２ and 15 g / m ２ 50g / m or more ２ The following ranges are included:

[0078] When a sealant layer coating liquid is prepared by dissolving or dispersing a heat-sealable resin in a solvent, and the sealant layer is formed by coating the sealant layer on the barrier layer and drying, the sealant layer coating liquid preferably comprises a water-dispersible resin dispersed in an aqueous solvent. Here, "aqueous" means containing 50% or more by mass of water. That is, the sealant layer preferably contains a water-dispersible resin. Examples of water-dispersible resins include those previously mentioned as water-suspendable polymers other than polyurethane resins. Preferred examples include polyolefin resins, styrene / acrylic copolymers, acrylic resins such as ethylene-(meth)acrylic acid copolymers, ethylene-vinyl acetate copolymers, polyester resins, rubber-based resins, urethane resins, and polyamide resins. These may be used alone or in combination of two or more. Among these, it is preferable to contain an acrylic resin, and it is more preferable to contain an aqueous acrylic resin such as a styrene / acrylic copolymer. The advantages of acrylic resins are as described above. Either commercially available or synthetic acrylic resins may be used as the acrylic resin. As commercially available products, those exemplified in the section on the thermoplastic resin layer may be used. In addition to these resins, lubricants such as paraffin wax, carnauba wax, and polyolefin wax, and pigments such as silica and kaolin may be added to prevent blocking and improve oil resistance.

[0079] The solvent for dispersing the water-dispersible resin is not particularly limited, and may be water or an organic solvent such as ethanol, isopropyl alcohol, methyl ethyl ketone, toluene, etc. Among these, from the viewpoint of not causing the problem of volatile organic solvents, an aqueous medium is preferred, and water is more preferred, as the dispersion medium for the sealant layer coating liquid.

[0080] When forming the sealant layer by coating, the amount of coating is not particularly limited, but from the viewpoint of heat sealing property, it is preferably 1 g / m as a solid content after drying. ２ More preferably, 2 g / m ２ From the viewpoint of redisintegration, it is preferably 20 g / m ２ More preferably, it is 15 g / m or less. ２ When forming a sealant layer by coating, the preferred range of the coating amount is 1 g / m or less. ２ 20g / m or more ２ and 2 g / m ２ 15g / m or more ２ The following ranges are included:

[0081] (Undercoat layer) The laminate of this embodiment may have an undercoat layer (hereinafter also referred to as a clay coat layer) between the paper substrate and the barrier layer, which can seal and smooth the paper substrate and improve the barrier properties.

[0082] The undercoat layer is preferably formed by applying an aqueous coating liquid in which an inorganic pigment and a binder are dispersed in an aqueous medium, followed by drying. Forming the undercoat layer in this manner results in a undercoat layer with a high sealing effect. Furthermore, upon re-disintegration, the components of the undercoat layer are redispersed in water, allowing the pulp to be recovered at a high recovery rate (i.e., resulting in a laminate with excellent recyclability). Therefore, in the laminate, the undercoat layer is preferably formed by applying a coating liquid in which a binder is dispersed in an aqueous medium, and preferably contains an inorganic pigment and a binder. Furthermore, the binder is preferably a water-dispersible polymer.

[0083] The undercoat layer preferably contains an inorganic pigment and a binder, and more preferably is mainly composed of an inorganic pigment and a binder. The phrase "the undercoat layer is mainly composed of an inorganic pigment and a binder" means that the total content of the inorganic pigment and the binder in the undercoat layer is preferably 50% by mass or more, more preferably 60% by mass or more, even more preferably 70% by mass or more, even more preferably 80% by mass or more, even more preferably 90% by mass or more, and particularly preferably 95% by mass or more (upper limit: 100% by mass or less). The undercoat layer may further contain any optional components in addition to the inorganic pigment and the binder.

[0084] The inorganic pigment contained in the undercoat layer is not particularly limited, but examples thereof include clays such as kaolin, talc, and mica, and metal oxides. Clay is preferred, and kaolin is more preferred. The inorganic pigment may be used alone, or two or more types may be used in combination. The aspect ratio of the inorganic pigment is usually 1 or more, preferably 10 or more, more preferably 20 or more, and even more preferably 30 or more. The upper limit is not particularly limited, but is preferably 10,000 or less. From the viewpoint of finely dispersing the inorganic pigment in the undercoat layer and improving the disintegration properties of the paper substrate during recovery, 50 or less is preferred, and 40 or less is more preferred. In other words, preferred ranges for the aspect ratio of the inorganic pigment include 1 or more and 10,000 or less, 10 or more and 50 or less, 20 or more and 40 or less, and 30 or more and 40 or less. The aspect ratio can be measured by observation with an electron microscope or X-ray diffraction measurement.

[0085] The average particle size of the inorganic pigment is preferably 5 μm or less, more preferably 3 μm or less, and even more preferably 1 μm or less, from the viewpoint of finely dispersing the inorganic pigment in the undercoat layer and improving the disintegration properties of the paper substrate during recovery. The lower limit is not particularly limited, but is preferably 0.05 μm or more, and more preferably 0.10 μm or more. In other words, preferred ranges for the average particle size of the inorganic pigment include 0.05 μm to 5 μm, 0.10 μm to 3 μm, and 0.10 μm to 1 μm. The average particle size refers to the median diameter (d50) measured by laser diffraction / scattering particle size distribution measurement.

[0086] From the viewpoint of recyclability, the content of the inorganic pigment in the undercoat layer is usually 50% by mass or more, may be 60% by mass or more, and is preferably 65% ​​by mass or more, and from the viewpoint of increasing adhesion to the paper substrate and further improving barrier properties, it is preferably 98% by mass or less, more preferably 95% by mass or less, even more preferably 90% by mass or less, and still more preferably 85% by mass or less. That is, preferred ranges for the content of the inorganic pigment in the undercoat layer include from 50% by mass to 98% by mass, from 60% by mass to 95% by mass, from 65% by mass to 90% by mass, and from 65% by mass to 85% by mass.

[0087] When the binder contained in the undercoat layer is a water-dispersible polymer, from the viewpoint of recyclability, the glass transition temperature of the water-dispersible polymer is preferably 20° C. or lower, more preferably 10° C. or lower, and preferably −5° C. or higher. The glass transition temperature of the water-dispersible polymer is a value measured by the method for measuring transition temperatures of plastics (JIS K7121:2012).

[0088] The binder contained in the undercoat layer is not particularly limited, but examples thereof include styrene-butadiene resins, (meth)acrylic (co)polymers, styrene-(meth)acrylic resins, olefin-unsaturated carboxylic acid copolymers such as ethylene-acrylic acid copolymers and ethylene-methacrylic acid copolymers, polylactic acid, etc. The binder preferably contains one or more selected from the group consisting of styrene-butadiene resins, styrene-(meth)acrylic resins, olefin-unsaturated carboxylic acid copolymers, and polylactic acid, and more preferably contains one or more selected from the group consisting of styrene-(meth)acrylic resins, ethylene-(meth)acrylic acid copolymers, and polylactic acid.

[0089] The (meth)acrylic (co)polymer is a (co)polymer of one or more monomers selected from (meth)acrylic acid and (meth)acrylic acid esters. The (meth)acrylic acid ester is not particularly limited, but is preferably an alkyl ester of (meth)acrylic acid having 1 to 12 carbon atoms. The styrene-(meth)acrylic resin is a copolymer of styrene and at least one monomer selected from (meth)acrylic acid and (meth)acrylic acid esters.

[0090] The binder content in the undercoat layer is usually 50% by mass or less, and may be 40% by mass or less, and from the viewpoint of recyclability, is preferably 35% by mass or less, and from the viewpoint of increasing adhesion to the paper substrate and further improving barrier properties, is preferably 2% by mass or more, more preferably 5% by mass or more, even more preferably 10% by mass or more, and still more preferably 15% by mass or more. That is, preferred ranges for the binder content in the undercoat layer include 2% by mass or more and 50% by mass or less, 5% by mass or more and 40% by mass or less, 10% by mass or more and 35% by mass or less, and 15% by mass or more and 35% by mass or less.

[0091] Optional components that the undercoat layer may contain include dispersants, surfactants, antioxidants, antistatic agents, dyes, plasticizers, lubricants, and release agents.

[0092] The coating amount (solid content) of the undercoat layer is set to 3 g / m from the viewpoint of enhancing the sealing effect. ２ It is preferable that the content is 5 g / m or more. ２ It is more preferable that the thickness is 30 g / m or more, and from the viewpoint of recyclability, ２ It is preferable that the weight is 20 g / m or less. ２ That is, the preferred range of the coating amount (solid content) of the undercoat layer is 3 g / m or less. ２ 30g / m or more ２ or less, and 5 g / m ２ 20g / m or more ２ The following ranges are included:

[0093] The method for forming the undercoat layer is not particularly limited, but a method of forming the undercoat layer by coating a dispersion containing an inorganic pigment and a binder on a paper substrate and drying it is preferred. The dispersion containing an inorganic pigment and a binder is preferably one that uses an aqueous medium such as an aqueous dispersion as a solvent.

[0094] (Other Layers) The laminate according to this embodiment may include layers other than those described above. For example, it may include an adhesive layer (adhesive resin layer), and if even higher barrier properties are required, it may also include an inorganic substance layer. Known adhesive layers and inorganic substance layers can be used. For example, inorganic substance layers include a vapor deposition layer vapor-deposited on a resin film, and a laminate of a resin film and aluminum foil. As described above, the vapor deposition layer may be an aluminum vapor deposition layer, an alumina vapor deposition layer, or a silica vapor deposition layer. The laminate according to this embodiment may further include any layer such as a printed layer or a light-shielding layer.

[0095] (Barrier Properties of Laminate) The laminate according to this embodiment has a water vapor permeability of 50 g / m or less, measured at 40° C. and 90% RH in accordance with JIS-Z-0208:1976. ２ - It is preferable that it is less than 40 g / m ２ ・day or less, and 30 g / m ２ It is more preferable that the density is 20 g / m or less. ２ It is more preferable that the density is 15 g / m or less. ２ It is even more preferable that the density is 10 g / m or less. ２ It is particularly preferable that the density is 8 g / m or less. ２ It is particularly preferable that the moisture barrier property is not more than 1000 g / m. The moisture barrier property is in the above range. The lower the lower limit, the better, so there is no particular restriction, but it is preferably 0 g / m. ２ ・Over 1 day, 1g / m ２ ・Over 2 days, 2g / m ２ ・Over 1 day, 3g / m ２ That is, the preferred range of the water vapor permeability of the laminate at 40°C and 90% RH is 0 g / m ２ ・Over 50g / m２ ・Less than day, 0 g / m ２ ・Over 40g / m ２ ・Less than day, 1g / m ２ ・30g / m for more than a day ２ ・Less than day, 1g / m ２ ・20g / m for more than a day ２ ・Less than day, 2g / m ２ ・15g / m for more than 1 day ２ ・Less than day, 2g / m ２ ・10g / m for more than a day ２ ・day or less, and 3g / m ２ ・8g / m over 1 day ２ The water vapor permeability can be controlled by, for example, selecting the thickness of the barrier layer or the components contained in the barrier layer.

[0096] In addition, when a CPP film was attached to the laminate, the oxygen permeability at 23°C and 50% RH was 10.0 mL / m ２ The oxygen permeability is preferably 8.0 mL / m or less. ２ ·day·atm or less, and preferably 5.0 mL / m ２ More preferably, it is 3.0 mL / m or less. ２ More preferably, it is 2.0 mL / m or less. ２ It is even more preferable that the concentration is 1.5 mL / m or less. ２ More preferably, the concentration is 1.0 mL / m or less. ２ It is particularly preferable that the concentration is 0.5 mL / m or less. ２ It is particularly preferable that the oxygen barrier property is not more than 100 mL / m. The above range indicates that the oxygen barrier property is very high. The lower limit is not particularly limited, as the lower the better, but it is preferably 0.0 mL / m. ２ ・day・atm or more, 0.1mL / m ２ That is, the preferred range of oxygen transmission rate at 23°C and 50% RH when a CPP film is attached to the laminate is 0.0 mL / m or more. ２ ・day・atm or more 10.0mL / m２ ・day・atm or less, 0.0mL / m ２ ・day・atm or more 8.0mL / m ２ ・day・atm or less, 0.0mL / m ２ ・day・atm or more 5.0mL / m ２ ・day・atm or less, 0.0mL / m ２ ・day・atm or more 3.0mL / m ２ ・day・atm or less, 0.1mL / m ２ ・day・atm or more 2.0mL / m ２ ・day・atm or less, 0.1mL / m ２ ・day・atm or more 1.5mL / m ２ ・day・atm or less, 0.1mL / m ２ ・day・atm or more 1.0mL / m ２ ・day・atm or less and 0.1mL / m ２ ・day・atm or more 0.5mL / m ２ The oxygen permeability can be controlled by, for example, selecting the thickness of the barrier layer or the components contained in the barrier layer.

[0097] In addition, when a CPP film was attached to the laminate, the oxygen permeability at 23°C and 85% RH was 10.0 mL / m ２ Preferably, the concentration is 8.0 mL / m or less. ２ More preferably, it is 5.0 mL / m or less. ２ More preferably, the concentration is 3.0 mL / m or less. ２ It is even more preferable that the concentration is 2.0 mL / m or less. ２ It is particularly preferable that the concentration is 1.5 mL / m or less. ２ More preferably, the concentration is 1.0 mL / m or less. ２ The lower limit is not particularly limited, as the lower the better, but it is preferably 0.0 mL / m ２ ・day・atm or more, 0.1mL / m ２That is, the preferred range of oxygen transmission rate at 23°C and 85% RH when a CPP film is attached to the laminate is 0.0 mL / m or more. ２ ・day・atm or more 10.0mL / m ２ ・day・atm or less, 0.0mL / m ２ ・day・atm or more 8.0mL / m ２ ・day・atm or less, 0.0mL / m ２ ・day・atm or more 5.0mL / m ２ ・day・atm or less, 0.1mL / m ２ ・day・atm or more 3.0mL / m ２ ・day・atm or less, 0.1mL / m ２ ・day・atm or more 2.0mL / m ２ ・day・atm or less, 0.1mL / m ２ ・day・atm or more 1.5mL / m ２ ・day・atm or less and 0.1mL / m ２ ・day・atm or more 1.0mL / m ２ ・The following ranges are included: day・atm.

[0098] The oxygen permeability at 85% RH satisfying the above range indicates that the film exhibits sufficient gas barrier properties even in a high-humidity environment. The oxygen permeability at 85% RH can be adjusted to fall within the above range by selecting the material used for the barrier layer.

[0099] (Weight ratio of paper substrate) The weight ratio of the paper substrate is a value obtained by calculating the percentage based on the total weight of the laminate as follows: (Weight ratio of paper substrate) = (Weight of paper substrate) / (Weight of laminate) × 100 The weight ratio of the paper substrate is preferably 75% or more, more preferably 80% or more. When the weight ratio of the paper substrate is equal to or greater than the lower limit, a laminate with a high biomass ratio and reduced environmental impact can be provided. The upper limit is not particularly limited, but is usually 99% or less, and preferably 95% or less. That is, preferred ranges for the weight ratio of the paper substrate include 75% or more and 99% or less, and 80% or more and 95% or less.

[0100] The laminate according to this embodiment has excellent water vapor barrier properties and gas barrier properties, and therefore can be suitably used as a paper product. Examples of the paper product include liquid containers, paper containers, and paper cups. The laminate can also be suitably used as a paper product such as a packaging material for food, cosmetics, daily necessities, medical products, electronic components, etc. The laminate can also be suitably used as a paper product such as a packaging material for contents that have a fragrance or odor. The laminate can also be suitably used as a paper product such as a packaging material for food, cosmetics, daily necessities, medical products, electronic components, etc. that are exposed to high humidity conditions. The laminate may be a barrier laminate.

[0101] [Liquid Container] A liquid container can be manufactured by molding the laminate of this embodiment using a known method. The shape of the liquid container is not particularly limited, and may be, for example, a roof type (gable top type), a rectangular parallelepiped type (flat top type, brick type, straight type, etc.), a triangular pyramid type, a slant top type, a regular tetrahedron type, a cup type, a tray type, etc. Furthermore, the liquid container may be equipped with a straw insertion hole, a spout, a lid material, etc., as long as the barrier properties are not impaired.

[0102] The liquid contained in the liquid container may be either food or non-food. The liquid to be contained in the liquid container is not particularly limited and may include alcoholic beverages such as sake, shochu, and wine; dairy beverages such as milk; beverages such as juice, coffee, tea, and black tea; liquid foods such as instant foods, microwaveable foods, beverages (yogurt, jelly, pudding, etc.), and prepared dishes; pharmaceuticals; and chemical products such as car wax, shampoo, conditioner, detergent, bath additives, hair dye, and toothpaste.

[0103] Examples will be given below to specifically explain the present disclosure, but the present disclosure is not limited to these examples. Unless otherwise specified, the following operations were performed under conditions of 25°C and a relative humidity of 50% RH. Furthermore, in the examples and comparative examples, "parts" and "%" refer to "parts by mass" and "% by mass," respectively, unless otherwise specified.

[0104] Example 1 To 33.3 parts by mass of an aqueous dispersion of a layered inorganic compound (swellable mica, major axis (average length) 6.3 μm, aspect ratio 1260, average thickness approximately 5 nm, solids concentration 6 mass%, product name: NTS-10NC, manufactured by Topy Industries, Ltd.), 5.1 parts by mass of a self-emulsifying emulsion of ethylene-acrylic acid copolymer (solids concentration 29.2 mass%, product name: ZAIKXEN AC, manufactured by Sumitomo Seika Chemicals Co., Ltd.) was added with stirring, and 26.7 parts by mass of a self-emulsifying aqueous emulsion of hydroxy polyurethane (solids concentration 30 mass%, product name: HPU-W013A, manufactured by Dainichiseika Color & Chemicals Mfg. Co., Ltd., hydroxyl value 235 mg KOH / g, acid value 30 mg KOH / g, glass transition temperature 70° C.) was further added and stirred. To this was added 0.57 parts by mass of a modified polyamide resin (surface charge 0.4 meq / g, solid content concentration 53% by mass, product name: SPI203(50)H, manufactured by Taoka Chemical Co., Ltd.) and stirred. Furthermore, 5.0 parts by mass of an aqueous solution prepared by dissolving ethylene-modified polyvinyl alcohol (product name: EXCEVAL RS-1717, manufactured by Kuraray Co., Ltd.) as a water-soluble polymer in water to a solid content concentration of 10% by mass was added. Furthermore, 0.30 parts by mass of a 25% by mass aqueous ammonia solution was added and stirred. Further, dilution water was added to make a solid content concentration of 19% by mass to form a barrier layer coating. The above barrier layer coating was mixed to a basis weight of 330 g / m ２ On one side of a paper substrate (OK Pienas, manufactured by Oji Materia Co., Ltd.), 5 g / m ２ The coating was applied so that the

[0105] A solvent-based adhesive (urethane-based, DiCdry LX-500 / K W-75, manufactured by DIC Corporation) was applied to a 40 μm L-LDPE film (FC-S, manufactured by Mitsui Tocello Co., Ltd., metallocene grade) at a dry weight of 4 g / m. ２ After the adhesive layer was formed by applying the adhesive layer to the barrier layer using a dry lamination method and then aging at 40°C for 3 days, a barrier layer, an adhesive layer, and a sealant layer were laminated on one side of the paper substrate. Furthermore, a polyethylene resin (Novatec LD LC600A, manufactured by Japan Polyethylene Co., Ltd.) was extruded onto the other side of the paper substrate to a thickness of 20 μm (basis weight: approximately 18 g / m) using an extrusion lamination method. ２) to form a thermoplastic resin layer (LDPE layer), thereby obtaining a laminate.

[0106] Example 2: A 40 μm thick film (weight: approximately 37 g / m) was produced by extrusion lamination without using any adhesive. ２ A laminate was obtained in the same manner as in Example 1, except that the sealant layer (LDPE layer) was formed by applying the composition onto the barrier layer so that the composition became 1 / 2 mm thick.

[0107] Example 3 A coating liquid for an undercoat layer was prepared by mixing 70 parts by mass of kaolin (Contour Xtreme, manufactured by Imerys, aspect ratio 33, average particle size d50: 0.26 μm) and 30 parts by mass (solid content) of a styrene-acrylic resin binder (ACRONAL S504, manufactured by BASF, glass transition temperature 5° C.). Before applying the barrier layer paint, the undercoat layer paint was applied to a substrate having a basis weight of 330 g / m. ２ On one side of a paper substrate (OK Pienas, manufactured by Oji Materia Co., Ltd.), 6 g / m ２ On top of that, a barrier layer paint was applied in a dry weight of 3 g / m ２ A laminate was obtained in the same manner as in Example 1, except that the coating was performed so that the thickness of the laminate was 1 / 2 mm.

[0108] Example 4: A 40 μm thick film (weight: approximately 37 g / m) was produced by extrusion lamination without using any adhesive. ２ A laminate was obtained in the same manner as in Example 3, except that the sealant layer (LDPE layer) was formed by applying the composition onto the barrier layer so that the composition became 1 / 2 mm thick.

[0109] Example 5 A laminate was obtained in the same manner as in Example 4, except that 1 part by mass (solid content) of polyethyleneimine (Epomin P-1000, manufactured by Nippon Shokubai) was further added to the barrier layer coating material.

[0110] Example 6 A laminate was obtained in the same manner as in Example 1, except that the 40 μm L-LDPE film was replaced with a 30 μm heat-sealable polyester film (DE046, manufactured by Toyobo Co., Ltd.).

[0111] Example 7 Polyethylene resin (Novatec LD LC600A, manufactured by Japan Polyethylene Co., Ltd.) was extrusion laminated onto the sealant layer (L-LDPE layer) of the paper laminate obtained in Example 1 to a thickness of 20 μm (weight: approximately 18 g / m ２ ) and then a sealant layer (LDPE layer) was formed to obtain a laminate.

[0112] Example 8 As a thermoplastic resin layer, instead of LDPE by the extrusion lamination method, an aqueous acrylic dispersion (solid content concentration 42% by mass, product name: Brightone FC-640V, manufactured by Sakata Inx) was diluted with water to a solid content concentration of 22% by mass, and the resulting thickness was 5 g / m ２ A laminate was obtained in the same manner as in Example 1, except that the coating was performed so that the thickness of the laminate was 1 / 2 mm.

[0113] Example 9 A water-based acrylic dispersion (solid content concentration 42% by mass, product name: Brightone FC-640V, manufactured by Sakata Inx, styrene-acrylic copolymer) was diluted with water to a solid content concentration of 22% by mass as a heat seal layer paint, and the paint was applied at a solid content of 10 g / m on the barrier layer. ２ A laminate was obtained in the same manner as in Example 1, except that the sealant layer was formed by coating the mixture so as to form a sealant layer.

[0114] Example 10 As a thermoplastic resin layer, instead of LDPE by the extrusion lamination method, an aqueous acrylic dispersion (solid content concentration 42% by mass, product name: Brightone FC-640V, manufactured by Sakata Inx, styrene-acrylic copolymer) was diluted with water to a solid content concentration of 22% by mass, and the resulting thickness was 5 g / m ２ A laminate was obtained in the same manner as in Example 9, except that the coating was performed so that the thickness of the laminate was 1 / 3.

[0115] Example 11: Paper substrate with a basis weight of 220 g / m ２ A laminate was obtained in the same manner as in Example 1, except that the paper substrate was changed to the above.

[0116] Example 12 A laminate was obtained in the same manner as in Example 1, except that the added number of parts of the modified polyamide resin was changed to 0.19 parts.

[0117] Example 13 A laminate was obtained in the same manner as in Example 1, except that the added number of parts of the modified polyamide resin was changed to 0.95 parts.

[0118] Example 14 As a sealant layer, the 40 μm L-LDPE film was replaced with a heat-seal type silica-alumina binary vapor-deposited polyester film (Ecosyar SS VE034, manufactured by Toyobo Co., Ltd.), and a solvent-based adhesive (urethane-based, DiCdry LX-500 / K W-75, manufactured by DIC Corporation) was applied in a dry weight of 4 g / m to the side of the film on which the vapor-deposited layer was formed. ２ The adhesive layer was then bonded to the barrier layer by dry lamination, and a laminate was obtained in the same manner as in Example 1.

[0119] Example 15 A laminate was obtained in the same manner as in Example 14, except that the adhesive layer was formed by changing the adhesive to a barrier adhesive (urethane-based, PASLIM VM001 / 108CP manufactured by DIC Corporation).

[0120] Example 16 A laminate was obtained in the same manner as in Example 1, except that the amount of the self-emulsifying emulsion of ethylene-acrylic acid copolymer added was changed to 6.8 parts by mass, the amount of the self-emulsifying aqueous emulsion of hydroxy polyurethane added was changed to 23.4 parts by mass, and the amount of the ethylene-modified polyvinyl alcohol aqueous solution (solid content concentration: 10% by mass) added was changed to 10.0 parts by mass to prepare a barrier layer coating material.

[0121] Example 17 A heat-sealable laminate was obtained in the same manner as in Example 1, except that the self-emulsifying aqueous emulsion of hydroxy polyurethane (solid content concentration 30% by mass, product name: HPU-W013A, manufactured by Dainichiseika Color & Chemicals Mfg. Co., Ltd.) used in the barrier layer coating was changed to a dispersion of polyurethane having a structural unit derived from metaxylylene diisocyanate (solid content concentration 30% by mass, product name: Takelac WPB-341(30), manufactured by Mitsui Chemicals, Inc.). １H-NMR analysis revealed that the content of metaxylylene diisocyanate-derived structural units relative to the total amount of polyisocyanate-derived structural units was 50 mol % or more. The glass transition temperature of the polyurethane resin was 130°C.

[0122] Comparative Example 1 A laminate was obtained in the same manner as in Example 1, except that the barrier layer coating material was not applied onto the paper substrate.

[0123] Comparative Example 2 The coating amount of the clay coating layer coating liquid shown in Table 1 below was 6.0 g / m on a dry basis. ２ The paper substrate was coated with the coating solution for the barrier layer shown in Table 2 below in a coating amount of 3.0 g / m2 in terms of dry weight, and then dried. ２ A laminate was obtained in the same manner as in Example 3, except that the coating was carried out by the air knife method so that the thickness of the coating was as follows:

[0124]

[0125]

[0126] Comparative Example 3 A laminate was obtained in the same manner as in Example 1, except that synthetic mica was not added to the barrier layer coating material.

[0127] Comparative Example 4 A laminate was obtained in the same manner as in Example 1, except that the cationic resin of the barrier layer coating material was not added.

[0128] Comparative Example 5 A solvent-based non-gas barrier adhesive (DIC Dry LX-500 / KW-75, manufactured by DIC Graphics Corporation) was applied at a dry weight of 4 g / m to the alumina-deposited surface of a 12 μm thick PET film (Barrierox 1031HG, manufactured by Toray Industries, Inc.). ２ An L-LDPE film 60 μm thick (FC-S, manufactured by Mitsui Tocello Co., Ltd., metallocene grade) was then attached to the adhesive layer of the PET film with alumina vapor deposition on one side as a sealant layer. The resulting laminated film had a basis weight of 330 g / m ２One side of a paper substrate (OK Pienas, manufactured by Oji Materia Co., Ltd.) was extrusion laminated to a thickness of 20 μm using an ethylene-methacrylic acid copolymer (EMAA, Nucrel N0908C, Mitsui-Dow Polychemicals Co., Ltd.) so that the adhesive surface of the paper substrate was bonded to a PET film with alumina vapor deposition on one side. Furthermore, a polyethylene resin (Novatec LD LC600A, manufactured by Japan Polyethylene Co., Ltd.) was extrusion laminated to a thickness of 20 μm (weight: approximately 18 g / m) on the other side of the paper substrate. ２ ) to form a resin layer (LDPE layer), thereby obtaining a laminate.

[0129] The following evaluations were carried out on the obtained laminates of Examples 1 to 16 and Comparative Examples 1 to 5. The results are shown in Tables 3 and 4.

[0130] [Oxygen Permeability] Using an oxygen permeability measuring device (OX-TRAN2 / 22 manufactured by MOCON Corporation), the oxygen permeability of the laminate was measured under conditions of a temperature of 23°C and a relative humidity of 50% and a temperature of 23°C and a relative humidity of 85%. Specifically, the oxygen permeability of the laminates obtained in the examples and comparative examples was measured in accordance with JIS K7126-2:2006 at a temperature of 23°C and a relative humidity of 50% and at a temperature of 23°C and a relative humidity of 85%. The lower the oxygen permeability value, the better the oxygen barrier property.

[0131] [Water Vapor Permeability] The water vapor permeability of the laminate was measured in accordance with JIS-Z-0208:1976 (cup method) Method B (40°C ± 0.5°C, relative humidity 90% ± 2%) with the sealant layer facing inward.

[0132] [Weight ratio of paper substrate] The weight ratio of the paper substrate was calculated as a percentage based on the total weight of the laminate as follows: (Weight ratio of paper substrate) = (Weight of paper substrate) / (Weight of laminate) x 100

[0133] [Laminate Adhesion] Two laminates were stacked with the sealant layers facing each other and heat-sealed using a heat seal tester (TP-701-B, manufactured by Tester Sangyo Co., Ltd.) at 180°C, 0.2 MPa, and 1 second. The heat-sealed test specimen was left to stand for at least 4 hours in a room at a temperature of 23°C ± 1°C and a humidity of 50% ± 2%. Next, the heat-sealed test specimen was cut into 15 mm widths and subjected to T-peel at a tensile speed of 300 mm / min using a tensile tester, and the fracture behavior was visually evaluated. If the paper substrate was fractured, the adhesion between the layers was judged to be good. A: The paper substrate was fractured. B: Breakage occurred between the paper and the sealant layer, and the paper substrate was not fractured.

[0134]

[0135]

[0136]

Claims

1. A thermoplastic resin layer, a paper base layer, a barrier layer, and a sealant layer, in this order; The laminate, wherein the barrier layer comprises a polyurethane resin, a swellable layered silicate, and a cationic resin.

2. The laminate according to claim 1 , wherein the polyurethane resin comprises at least one selected from the group consisting of polyurethanes having structural units derived from metaxylylene diisocyanate and hydroxy polyurethanes.

3. 3. The laminate according to claim 1, wherein the barrier layer contains 1.0 to 20.0% by mass of the cationic resin.

4. 3. The laminate according to claim 1, wherein the barrier layer contains 30.0 to 80.0% by mass of the polyurethane resin.

5. 3. The laminate according to claim 1, wherein the barrier layer contains 5.0 to 30.0% by mass of the swellable layered silicate.

6. the barrier layer further comprises at least one selected from the group consisting of water-dispersible polymers other than polyurethane resins and water-soluble polymers other than polyurethane resins; The water-dispersible polymer contains an olefin / unsaturated carboxylic acid copolymer, 3. The laminate according to claim 1, wherein the water-soluble polymer comprises at least one member selected from the group consisting of vinyl alcohol polymers and polyalkyleneimines.

7. the barrier layer further comprises a water-suspendable polymer other than the polyurethane resin and a water-soluble polymer other than the polyurethane resin, The laminate according to claim 1 or 2, wherein the barrier layer comprises the water-suspendable polymer and the water-soluble polymer in at least the following combination (A) or (B): (A) Water-suspendable polymer: ethylene-acrylic acid copolymer, water-soluble polymer: polyvinyl alcohol call (B) Water-suspendable polymer: ethylene-acrylic acid copolymer, water-soluble polymer: polyvinyl alcohol and polyethyleneimine

8. 7. The laminate according to claim 6, wherein the barrier layer contains 2.0 to 50.0% by mass in total of the water-dispersible polymer other than the polyurethane resin and the water-soluble polymer other than the polyurethane resin.

9. 7. The laminate according to claim 6, wherein a ratio of a mass of the polyurethane resin to a total mass of the water-suspendable polymer other than the polyurethane resin and the water-soluble polymer other than the polyurethane resin (mass of the polyurethane resin:total mass of the water-suspendable polymer and the water-soluble polymer) in the barrier layer is 50:50 to 95:

5.

10. The laminate according to claim 1 or 2, further comprising an undercoat layer between the paper base layer and the barrier layer.

11. The laminate according to claim 1 , wherein the sealant layer comprises a water-dispersible resin.

12. A processed paper product comprising the laminate according to claim 1 or 2.