Laminate

Abstract

Provided is a laminate excellent in water vapor barrier properties and oxygen barrier properties. The laminate includes, on a paper substrate, a precoat layer (A), a layer (B), and a vapor deposition layer (C) in this order. The precoat layer (A) contains at least one polymer (1) selected from the group consisting of water-soluble polymers and water-dispersible polymers. The layer (B) contains 50 mass% to less than 99 mass% of at least one polymer (2) selected from the group consisting of water-soluble polymers and water-dispersible polymers. The layer (B) also contains 1 mass% to less than 50 mass% of a layered inorganic compound (X) having an aspect ratio of 50 or greater.

Description

Laminate

[0001] The present invention relates to a laminate.

[0002] Paper packaging materials have traditionally been used as packaging materials for foods, medical products, electronic components, etc. As one such packaging material, Patent Document 1 describes grease-resistant paper obtained by applying a coating agent containing a carboxyl group-containing polyvinyl alcohol-based polymer to a paper substrate. However, the grease-resistant paper of Patent Document 1 has insufficient gas barrier properties (particularly water vapor barrier properties and oxygen barrier properties). As paper packaging materials for improving gas barrier properties, Patent Documents 2 and 3 describe paper packaging materials in which a water vapor barrier layer, a gas barrier layer, and a heat seal layer are laminated on a paper substrate, and the gas barrier layer contains a vinyl alcohol-based polymer (hereinafter, the vinyl alcohol-based polymer will also be referred to as "PVOH").

[0003] International Publication No. 2022 / 202997 Japanese Patent Application Laid-Open No. 2020-163675 Japanese Patent Application Laid-Open No. 2021-20398

[0004] Even the paper packaging materials of Patent Documents 2 and 3 do not have sufficient water vapor barrier properties and oxygen barrier properties, and the development of materials with even higher barrier properties is desired.

[0005] The present invention has been made to solve the above problems, and an object of the present invention is to provide a laminate having excellent water vapor barrier properties and oxygen barrier properties.

[0006] The above-mentioned problem is solved by the following: [1] a laminate having a precoat layer (A), a layer (B), and a vapor-deposited layer (C) on a paper substrate in this order, wherein the precoat layer (A) contains at least one polymer (1) selected from the group consisting of water-soluble polymers and water-dispersible polymers, and the layer (B) contains 50% by mass or more and less than 99% by mass of at least one polymer (2) selected from the group consisting of water-soluble polymers and water-dispersible polymers, and the layer (B) contains 1% by mass or more and less than 50% by mass of a layered inorganic compound (X) having an aspect ratio of 50 or more; [2] the laminate of [1], wherein the polymer (1) is at least one selected from the group consisting of an olefin-based polymer, a styrene-based polymer, a polyester-based polymer, a urethane-based polymer, and a vinyl alcohol-based polymer; [3] the laminate of [1] or [2], wherein the content of the polymer (1) in the precoat layer (A) is 50% by mass or more and less than 99% by mass; [4] The laminate of any one of [1] to [3], wherein the precoat layer (A) contains 1% by mass or more and less than 50% by mass of an inorganic compound (Y); [5] The laminate of [4], wherein the inorganic compound (Y) is a layered inorganic compound having an aspect ratio of 200 or more; [6] The laminate of any one of [1] to [5], wherein the polymer (2) is a vinyl alcohol-based polymer; [7] The laminate of [6], wherein the vinyl alcohol-based polymer of the polymer (2) has a viscosity-average degree of polymerization of 200 or more and 5,000 or less and a degree of saponification of 70 mol % or more and 100 mol % or less; [8] The laminate of any one of [1] to [7], wherein the heat seal layer (D) is on the outermost surface; [9] The laminate of [8], wherein the heat seal layer (D) contains at least one polymer (3) selected from the group consisting of an olefin-based polymer, a styrene-based polymer, and a polyester-based polymer;

[10] The laminate of [9], wherein the polymer (3) contains a styrene-acrylic copolymer;

[11] The problem is solved by providing any one of the laminates of [9] or

[10] , wherein the heat seal layer (D) contains 1 part by mass or more and 50 parts by mass or less of a vinyl alcohol-based polymer per 100 parts by mass of the polymer (3);

[12] Any one of the laminates of [8] to

[11] , wherein the heat seal layer (D) is located on the outermost surface of the paper base material, on the side of the vapor deposition layer (C).

[0007] According to the present invention, a laminate having excellent water vapor barrier properties and oxygen barrier properties can be provided.

[0008] <Laminate> A laminate according to one embodiment of the present invention has a precoat layer (A), a layer (B), and a vapor-deposited layer (C) on a paper substrate in this order, wherein the precoat layer (A) contains at least one polymer (1) selected from the group consisting of water-soluble polymers and water-dispersible polymers, the layer (B) contains 50% by mass or more and less than 99% by mass of at least one polymer (2) selected from the group consisting of water-soluble polymers and water-dispersible polymers, and the layer (B) contains 1% by mass or more and less than 50% by mass of a layered inorganic compound (X) having an aspect ratio of 50 or more.

[0009] The laminate according to one embodiment of the present invention has excellent water vapor barrier properties and oxygen barrier properties. Although the reason for this is unclear, it is presumed that the inclusion of an appropriate amount of layered inorganic compound (X) in layer (B) increases the smoothness of the surface of layer (B), and that the deposition layer (C) provided on such a smooth surface results in excellent water vapor barrier properties and oxygen barrier properties. Each layer will be described in detail below.

[0010] (Paper substrate) The paper substrate is a paper layer that serves as the base material in the laminate. The paper substrate may be the outermost layer on one side of the laminate. In other words, no other layer may be laminated on one side of the paper substrate. Other layers may be laminated on both sides of the paper substrate. The paper substrate may have a single-layer structure or a multi-layer structure. The paper substrate may be printed or the like.

[0011] The paper base material can be a general paper whose main component is plant-derived pulp. In this specification, the term "main component" refers to the component with the highest content by mass. In addition to pulp, the paper base material may contain sizing agents, fillers, paper strength agents, retention aids, pH adjusters, drainage aids, water-resistant agents, softeners, antistatic agents, antifoaming agents, slime control agents, dyes, pigments, etc.

[0012] Examples of paper substrates include kraft paper, bleached kraft paper, fine paper, medium-quality paper, alkaline paper, paperboard, glassine paper, semi-glassine paper, and parchment paper, with kraft paper or bleached kraft paper being preferred.

[0013] The basis weight (mass per unit area) of the paper base material is 20 g / m ２ More than 500g / m ２ Preferably, 30 g / m or less ２ More than 300g / m ２ More preferably, 40 g / m or less ２ More than 200g / m ２ More preferably, 50 g / m or less ２ More than 100g / m ２ Even more preferred are the following:

[0014] The density of the paper base material is 0.5 g / cm ３ 1.2g / cm or more ３ Preferably, 0.6 g / cm or less ３ 1.0g / cm or more ３ The following is more preferred:

[0015] The paper substrate can be produced by a known method, and commercially available paper substrates can also be used.

[0016] (Precoat Layer (A)) The precoat layer (A) is a layer located between the paper substrate and the layer (B). The precoat layer (A) may be a layer directly laminated on the paper substrate. The precoat layer (A) is usually a layer formed by coating (coating layer).

[0017] (Polymer (1)) The precoat layer (A) contains at least one polymer (1) selected from the group consisting of water-soluble polymers and water-dispersible polymers. The polymer (1) is preferably at least one selected from the group consisting of olefin-based polymers, styrene-based polymers, polyester-based polymers, urethane-based polymers, and vinyl alcohol-based polymers. When the precoat layer (A) contains these relatively hydrophobic polymers, it can exhibit good water vapor barrier properties, etc. The polymer (1) is preferably a water-dispersible polymer. The polymer (1) is preferably the main component of the precoat layer (A). One or more types of polymer (1) can be used.

[0018] (Olefin-Based Polymer) The olefin-based polymer is a polymer containing an olefin as a monomer. The olefin-based polymer may be a polyolefin, which is a polymer of one or more olefins, or a copolymer of one or more olefins with one or more other monomers other than olefins.

[0019] Examples of the olefin include α-olefins such as ethylene, propylene, n-butene, and isobutylene.

[0020] Examples of the monomer other than the olefin that constitutes the olefin polymer include an unsaturated carboxylic acid compound, a diene compound, a vinyl ester, a vinyl ether, a vinyl halide, a vinylidene halide, and an allyl compound. An unsaturated carboxylic acid compound or a vinyl ester is preferred, and an unsaturated carboxylic acid compound is more preferred.

[0021] The unsaturated carboxylic acid compound refers to an unsaturated carboxylic acid or a compound in which the hydrogen atom of the carboxy group constituting the unsaturated carboxylic acid is substituted with another atom or another group. That is, the unsaturated carboxylic acid compound includes not only unsaturated carboxylic acid but also unsaturated carboxylic acid esters, unsaturated carboxylic acid salts, etc. The unsaturated carboxylic acid compound is preferably a monomer having a carboxy group or a salt thereof.

[0022] Examples of unsaturated carboxylic acid compounds include unsaturated carboxylic acids such as (meth)acrylic acid, crotonic acid, cinnamic acid, itaconic acid, fumaric acid, maleic acid, and butenetricarboxylic acid; unsaturated carboxylic acid esters such as methyl (meth)acrylate, ethyl (meth)acrylate, itaconic acid monoethyl ester, and fumaric acid monobutyl ester; and unsaturated carboxylic acid salts such as sodium (meth)acrylate. Note that "(meth)acrylic acid" means acrylic acid and methacrylic acid.

[0023] Examples of vinyl esters include vinyl formate, vinyl acetate, vinyl propionate, vinyl valerate, vinyl caprate, vinyl laurate, vinyl stearate, vinyl benzoate, vinyl pivalate, vinyl versatate, etc. Of these, vinyl acetate is preferred.

[0024] The olefin polymer is preferably a polyolefin, an olefin-vinyl ester copolymer, or an olefin-unsaturated carboxylic acid copolymer, with an olefin-unsaturated carboxylic acid copolymer being more preferred. An olefin-vinyl ester copolymer refers to a copolymer of one or more olefins and one or more vinyl esters. An olefin-unsaturated carboxylic acid copolymer refers to a copolymer of one or more olefins and one or more unsaturated carboxylic acid compounds. Among the olefin-unsaturated carboxylic acid copolymers, an olefin-unsaturated carboxylic acid copolymer, which is a copolymer of one or more olefins and one or more unsaturated carboxylic acids, is preferred.

[0025] Examples of the olefin-vinyl ester copolymer include ethylene-vinyl formate copolymer, ethylene-vinyl acetate copolymer, and ethylene-vinyl propionate copolymer, among which ethylene-vinyl acetate copolymer is preferred. These copolymers may further be copolymerized with other monomers copolymerizable with the olefin and vinyl ester.

[0026] Examples of olefin-unsaturated carboxylic acid copolymers include ethylene-(meth)acrylic acid copolymer, ethylene-methyl(meth)acrylate copolymer, ethylene-ethyl(meth)acrylate copolymer, and ethylene-butyl(meth)acrylate copolymer. Among these, ethylene-(meth)acrylic acid copolymer is preferred. Copolymers of ethylene and unsaturated carboxylic acid compounds are also preferred. These copolymers may further be copolymerized with other monomers copolymerizable with the olefin and unsaturated carboxylic acid compound.

[0027] (Styrene-based polymer) A styrene-based polymer is a polymer containing a styrene-based compound as a monomer. The styrene-based compound refers to styrene and a compound in which the hydrogen atoms of styrene are substituted with other atoms or other groups. Examples of the styrene-based compound include styrene, α-methylstyrene, vinyltoluene, and chlorostyrene, with styrene being preferred.

[0028] Examples of the styrene copolymer include polystyrene, styrene-acrylic copolymer, and styrene-butadiene copolymer.

[0029] The styrene-acrylic copolymer is a copolymer of the above-mentioned styrene compound and an acrylic compound. The acrylic compound refers to (meth)acrylic acid and a compound in which the hydrogen atom of the carboxy group constituting (meth)acrylic acid is substituted with another atom or another group. Examples of the acrylic compound include (meth)acrylic acid, (meth)acrylic acid esters, and (meth)acrylic acid salts. Examples of the (meth)acrylic acid esters include (meth)acrylic acid alkyl esters such as methyl (meth)acrylate and ethyl (meth)acrylate. Examples of the (meth)acrylic acid salts include sodium (meth)acrylate.

[0030] Examples of styrene-acrylic copolymers include styrene-(meth)acrylic acid copolymers, styrene-(meth)acrylic acid ester copolymers, styrene-(meth)acrylate copolymers, etc. The styrene-acrylic copolymers may be further copolymerized with other monomers.

[0031] The styrene-butadiene copolymer is a copolymer of the above-mentioned styrene compound and a butadiene compound. The butadiene compound refers to butadiene and compounds in which the hydrogen atoms of butadiene have been substituted with other atoms or other groups. Examples of the butadiene compound include 1,3-butadiene, 2-methyl-1,3-butadiene (isoprene), 2,3-dimethyl-1,3-butadiene, and 1,3-pentadiene, with 1,3-butadiene being preferred.

[0032] The styrene-butadiene copolymer is preferably a styrene-butadiene copolymer, which may be further copolymerized with other monomers.

[0033] As the styrene polymer, a styrene-acrylic copolymer and a styrene-butadiene copolymer are preferred, and a styrene-acrylic copolymer is more preferred.

[0034] (Polyester-based polymer) A polyester-based polymer is a polymer in which one or more types of monomers are polymerized via an ester bond. Examples of the polyester-based polymer include polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, polyethylene naphthalate, polyglycolic acid, and aromatic liquid crystal polyester.

[0035] (Urethane-based polymer) The urethane-based polymer is a polymer having a urethane bond. The urethane-based polymer is typically a polymer obtained by reacting a polyisocyanate with a polyol. The urethane-based polymer preferably contains at least one of a metaxylylene diisocyanate-derived monomer unit and a hydrogenated metaxylylene diisocyanate-derived monomer unit. In the urethane-based polymer, the total content of the metaxylylene diisocyanate-derived monomer unit and the hydrogenated metaxylylene diisocyanate-derived monomer unit relative to the total amount of the polyisocyanate-derived monomer units is preferably 50 mol% or more. Such a urethane-based polymer exhibits high cohesive strength due to hydrogen bonds and the stacking effect between xylylene groups, and therefore has excellent gas barrier properties. The above content is １ The identification can be performed using known analytical techniques such as H-NMR.

[0036] The urethane polymer can be synthesized by a known method. For example, the urethane polymer described in WO 2015 / 016069 can be used.

[0037] The urethane polymer may be a commercially available product, such as "Takelac (registered trademark) W," "Takelac (registered trademark) WPB," or "Takelac (registered trademark) WS," manufactured by Mitsui Chemicals, Inc., and more specifically, "Takelac (registered trademark) WPB-341" may be used.

[0038] (Vinyl alcohol polymer) The vinyl alcohol polymer is a polymer having a vinyl alcohol unit (—CH ２ Vinyl alcohol polymers are generally obtained by saponifying vinyl ester polymers.

[0039] The viscosity-average degree of polymerization of the vinyl alcohol polymer is preferably 200 or more and 5,000 or less. The lower limit of the viscosity-average degree of polymerization may be 300, 500, or 800. On the other hand, the upper limit of the viscosity-average degree of polymerization may be 3,000, 2,500, 2,000, 1,200, or 800. When the viscosity-average degree of polymerization of the vinyl alcohol polymer is within the above range, the water vapor barrier property, oxygen barrier property, etc. can be further improved, and the coatability and the strength of the layer formed can also be optimized.

[0040] The viscosity-average degree of polymerization of a vinyl alcohol polymer is measured in accordance with JIS K 6726:1994. Specifically, the intrinsic viscosity [η] (liters / g) of the vinyl alcohol polymer is measured in water at 30°C, and the viscosity-average degree of polymerization P is calculated using the value of the intrinsic viscosity [η] according to the following formula. When the saponification degree of the vinyl alcohol polymer is less than 99.5 mol%, the polymer is saponified to a saponification degree of 99.5 mol% or more, and then the intrinsic viscosity [η] is measured. P = ([η] x 10 ４ / 8.29) （１／０．６２）

[0041] The lower limit of the saponification degree of the vinyl alcohol polymer is preferably 70 mol%, more preferably 80 mol%, more preferably 90 mol%, even more preferably 95 mol%, and may be 97 mol%, 98 mol%, or 99 mol%. When the saponification degree is equal to or higher than the above lower limit, the water vapor barrier property, oxygen barrier property, etc. can be further improved. On the other hand, the upper limit of the saponification degree may be 100 mol% or 99.9 mol%. The saponification degree of the vinyl alcohol polymer is measured in accordance with JIS K 6726:1994.

[0042] The vinyl alcohol polymer may have a monomer unit derived from a monomer other than the vinyl alcohol unit and the vinyl ester unit. Examples of such other monomers include α-olefins such as ethylene, propylene, n-butene, and isobutylene; (meth)acrylic acid and its salts; (meth)acrylic acid esters; (meth)acrylamide; (meth)acrylamide derivatives such as N-methyl(meth)acrylamide, N-ethyl(meth)acrylamide, N,N-dimethyl(meth)acrylamide, diacetone(meth)acrylamide, (meth)acrylamidopropanesulfonic acid and its salts, (meth)acrylamidopropyldimethylamine and its salts or quaternary salts thereof, and N-methylol(meth)acrylamide and its derivatives; methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, and i-propyl vinyl ether. Examples of suitable vinyl ethers include vinyl ethers such as n-butyl vinyl ether, i-butyl vinyl ether, t-butyl vinyl ether, dodecyl vinyl ether, and stearyl vinyl ether; nitriles such as acrylonitrile and methacrylonitrile; vinyl halides such as vinyl chloride and vinyl fluoride; vinylidene halides such as vinylidene chloride and vinylidene fluoride; allyl compounds such as allyl acetate and allyl chloride; unsaturated dicarboxylic acids and salts or esters thereof such as maleic acid, itaconic acid, and fumaric acid; vinyl silyl compounds such as vinyltrimethoxysilane; isopropenyl acetate; 1,4-diacetoxybutene; 3,4-diacetoxy-1-butene; vinylformamide; and vinylpyrrolidone. In this specification, a vinyl alcohol polymer that is substantially free of monomer units derived from other monomers than vinyl alcohol units and vinyl ester units is also referred to as polyvinyl alcohol.

[0043] The other monomer is preferably an α-olefin, and more preferably ethylene. That is, the vinyl alcohol polymer may be an α-olefin-vinyl alcohol copolymer or an ethylene-vinyl alcohol copolymer (ethylene-modified polyvinyl alcohol). Use of such a vinyl alcohol polymer can improve the water vapor barrier property after bending, etc.

[0044] The lower limit of the content of α-olefin units relative to all monomer units in the α-olefin-vinyl alcohol copolymer is preferably 0.1 mol%, more preferably 0.5 mol%, even more preferably 1 mol%, and may be 2 mol% or 3 mol%. On the other hand, the upper limit of this content is preferably 20 mol%, more preferably 15 mol%, even more preferably 13 mol%, and may be 10 mol% or 8 mol%. The lower limit of the content of ethylene units relative to all monomer units in the ethylene-modified polyvinyl alcohol (hereinafter sometimes referred to as the ethylene modification amount) is preferably 0.1 mol%, more preferably 0.5 mol%, even more preferably 1 mol%, and may be 2 mol% or 3 mol%. On the other hand, the upper limit of this content is preferably 20 mol%, more preferably 15 mol%, even more preferably 13 mol%, and may be 10 mol% or 8 mol%.

[0045] The total content of vinyl alcohol units, vinyl ester units, and any α-olefin units relative to all monomer units in the vinyl alcohol polymer is preferably 95 mol% or more, more preferably 99 mol% or more, and may be 100 mol%.

[0046] From the viewpoint of water vapor barrier properties, etc., polymer (1) is preferably at least one selected from the group consisting of olefin polymers, styrene polymers, and vinyl alcohol polymers, more preferably at least one selected from the group consisting of olefin polymers and vinyl alcohol polymers, and even more preferably an olefin polymer. When an olefin polymer is used as polymer (1), among olefin polymers, an olefin-unsaturated carboxylic acid copolymer is preferred, an olefin-unsaturated carboxylic acid copolymer is more preferred, and an ethylene-(meth)acrylic acid copolymer is even more preferred. When a vinyl alcohol polymer is used as polymer (1), among vinyl alcohol polymers, an α-olefin-vinyl alcohol copolymer is preferred, and ethylene-modified polyvinyl alcohol is more preferred.

[0047] The lower limit of the content of polymer (1) in the precoat layer (A) is preferably 50% by mass, more preferably 60% by mass, and even more preferably 70%, 80%, or 90% by mass. On the other hand, this content is preferably less than 99% by mass. The upper limit of the content is more preferably 98% by mass, and may be 96%, 90%, or 80% by mass.

[0048] (Inorganic Compound (Y)) The precoat layer (A) preferably contains an inorganic compound (Y). When the precoat layer (A) contains the inorganic compound (Y), the water vapor barrier property, oxygen barrier property, etc. can be improved. The inorganic compound (Y) is not particularly limited, and inorganic oxides, inorganic nitrides, inorganic salts, metals, etc. can be used, but a layered inorganic compound is preferable. When a layered inorganic compound is used as the inorganic compound (Y), the water vapor barrier property, oxygen barrier property, etc. can be further improved. Examples of layered inorganic compounds include micas, mica, talc, montmorillonite, kaolinite, vermiculite, smectite, hectorite, taeniolite, acid clay, etc. The layered inorganic compound may be a natural product or a synthetic product. One or more types of inorganic compound (Y) can be used.

[0049] The inorganic compound (Y) is usually in the form of particles. The average particle size of the inorganic compound (Y) is preferably 1 μm or more and 50 μm or less, and more preferably 4 μm or more and 30 μm or less. When the average particle size of the inorganic compound (Y) is within the above range, the water vapor barrier property, oxygen barrier property, etc. can be further improved. The average particle size is the average value of the particle sizes (longest diameter) of any 20 particles in a magnified image obtained by atomic force microscopy.

[0050] When the inorganic compound (Y) is a layered inorganic compound, the aspect ratio of the layered inorganic compound may be, for example, 20 or more, preferably 100 or more, and more preferably 200 or more. The aspect ratio may be, for example, 10,000 or less, 7,000 or less, 3,000 or less, or 1,000 or less. The aspect ratio refers to the average major diameter relative to the average thickness of flat particles. The average thickness and average major diameter are the average values ​​of the thickness and major diameter (longest diameter) of any 20 particles in an enlarged image obtained by atomic force microscopy.

[0051] The lower limit of the content of the inorganic compound (Y) in the precoat layer (A) is preferably 1% by mass, more preferably 2% by mass, even more preferably 3% by mass, and may be 4%, 5%, 6%, 7%, or 8% by mass. On the other hand, this content is preferably less than 50% by mass. The upper limit of the content is more preferably 40% by mass, even more preferably 30% by mass, and may be 20%, 10%, or 8% by mass. Furthermore, the lower limit of the content of the inorganic compound (Y) relative to 100 parts by mass of the polymer (1) in the precoat layer (A) is preferably 0.2 parts by mass, more preferably 1 part by mass, even more preferably 2 parts by mass, and may be 3 parts by mass, 4 parts by mass, 5 parts by mass, 6 parts by mass, 7 parts by mass, or 8 parts by mass. On the other hand, the upper limit of the content may be 80 parts by mass, but is preferably 40 parts by mass, more preferably 30 parts by mass, even more preferably 20 parts by mass, and even more preferably 10 parts by mass. By setting the content of the inorganic compound (Y) in the precoat layer (A) within the above range, it is possible to further improve the water vapor barrier property, oxygen barrier property, etc., especially these barrier properties after bending.

[0052] (Other Components, etc.) The precoat layer (A) may further contain components other than the polymer (1) and the inorganic compound (Y). Examples of the other components include resins other than the polymer (1), dispersants, surfactants, antifoaming agents, dyes, thickeners, etc.

[0053] Examples of resins other than the polymer (1) include cationic resins. When the precoat layer (A) contains a cationic resin together with the inorganic compound (Y), the water vapor barrier properties and the like may be further improved. Examples of the cationic resin include polyamine resins, cation-modified polyamide resins (for example, amine-modified polyamide resins), polyamide epichlorohydrin resins, polyethyleneimine resins, polyalkylene polyamine resins, polyamide compounds, polyamidoamine-epihalohydrin or formaldehyde condensation reaction products, polyamine-epihalohydrin or formaldehyde condensation reaction products, polyamide polyurea-epihalohydrin or formaldehyde condensation reaction products, polyamine polyurea-epihalohydrin or formaldehyde condensation reaction products, polyamidoamine polyurea-epihalohydrin or formaldehyde condensation reaction products, polyamide polyurea compounds, polyamine polyurea compounds, polyamidoamine polyurea compounds, polyamidoamine compounds, polyvinylpyridine, amino-modified acrylamide compounds, polyvinylamine resins, and polydiallyldimethylammonium chloride. Among these, at least one selected from the group consisting of polyamine resins, cation-modified polyamide resins, polyamide epichlorohydrin resins, and polyethyleneimine resins is preferred.

[0054] The total content of the polymer (1) and the inorganic compound (Y) in the precoat layer (A) may be 90% by mass or more, 95% by mass or more, 99% by mass or more, or substantially 100% by mass.

[0055] The lower limit of the mass per unit area of ​​one precoat layer (A) is 1 g / m ２ is preferred, and 3 g / m ２ More preferably, 5 g / m ２ More preferably, 7 g / m ２ When the mass per unit area of ​​one precoat layer (A) is equal to or greater than the above lower limit, the water vapor barrier property, oxygen barrier property, etc. can be further improved. The upper limit of the mass per unit area of ​​one precoat layer (A) is 100 g / m ２ is preferred, and 40 g / m ２More preferably, 20 g / m ２ More preferably, 15 g / m ２ When the mass per unit area of ​​one precoat layer (A) is equal to or less than the above upper limit, it is possible to reduce the thickness of the laminate.

[0056] (Layer (B)) The layer (B) is a layer located on the side of the precoat layer (A) opposite to the paper substrate. The layer (B) may be a layer directly laminated on the precoat layer (A). The layer (B) is usually a layer formed by coating (coating layer).

[0057] (Polymer (2)) Layer (B) contains at least one polymer (2) selected from the group consisting of water-soluble polymers and water-dispersible polymers. Examples of the water-soluble polymer and water-dispersible polymer that are polymer (2) include the olefin-based polymers, styrene-based polymers, polyester-based polymers, urethane-based polymers, and vinyl alcohol-based polymers exemplified as specific examples of polymer (1). As polymer (2), at least one selected from the group consisting of vinyl alcohol-based polymers and urethane-based polymers is preferred, and vinyl alcohol-based polymers are more preferred. By using at least one selected from the group consisting of vinyl alcohol-based polymers and urethane-based polymers as polymer (2), the water vapor barrier property, oxygen barrier property, etc. of the laminate can be improved.

[0058] The vinyl alcohol polymer as polymer (2) may be an α-olefin-vinyl alcohol copolymer or an ethylene-modified polyvinyl alcohol. Specific forms of the vinyl alcohol polymer as polymer (2) are the same as those of the vinyl alcohol polymer as polymer (1) described above. Polymer (2) may be used alone or in combination of two or more types.

[0059] The viscosity-average degree of polymerization of the vinyl alcohol polymer that is polymer (2) is preferably 200 or more and 5,000 or less. The lower limit of the viscosity-average degree of polymerization may be 300, 500, or 800. On the other hand, the upper limit of the viscosity-average degree of polymerization may be 3,000, 2,500, 2,000, 1,200, or 800. When the viscosity-average degree of polymerization of the vinyl alcohol polymer that is polymer (2) is within the above range, the water vapor barrier property, oxygen barrier property, etc. can be further improved, and the coatability and strength of the layer that is formed can also be optimized.

[0060] The lower limit of the saponification degree of the vinyl alcohol polymer (polymer (2)) is preferably 70 mol%, more preferably 80 mol%, more preferably 90 mol%, even more preferably 95 mol%, and may be 97 mol%, 98 mol%, or 99 mol%. When the saponification degree is equal to or greater than the above lower limit, the water vapor barrier property, oxygen barrier property, etc. can be further improved. On the other hand, the upper limit of the saponification degree may be 100 mol% or may be 99.9 mol%.

[0061] The lower limit of the content of α-olefin units relative to all monomer units in the α-olefin-vinyl alcohol copolymer that is polymer (2) is preferably 0.1 mol%, more preferably 0.5 mol%, even more preferably 1 mol%, and may be 2 mol% or 3 mol%. On the other hand, the upper limit of this content is preferably 20 mol%, more preferably 15 mol%, even more preferably 13 mol%, and may be 10 mol% or 8 mol%. The lower limit of the content of ethylene units relative to all monomer units in the ethylene-modified polyvinyl alcohol that is polymer (2) is preferably 0.1 mol%, more preferably 0.5 mol%, even more preferably 1 mol%, and may be 2 mol% or 3 mol%. On the other hand, the upper limit of this content is preferably 20 mol%, more preferably 15 mol%, even more preferably 13 mol%, and may be 10 mol% or 8 mol%.

[0062] The total content of vinyl alcohol units, vinyl ester units, and any α-olefin units relative to all monomer units in the vinyl alcohol polymer that is polymer (2) is preferably 95 mol % or more, more preferably 99 mol % or more, and may be 100 mol %.

[0063] The specific and preferred embodiments of the urethane polymer as polymer (2) are the same as the specific and preferred embodiments of the urethane polymer as polymer (1) described above.

[0064] The lower limit of the content of polymer (2) in layer (B) is 50% by mass, preferably 60% by mass, more preferably 70% by mass, even more preferably 80% by mass, even more preferably 90% by mass, and may be 92% by mass or 94% by mass. By setting the content of polymer (2) in layer (B) to the above-mentioned lower limit or more, it is possible to improve the water vapor barrier property, oxygen barrier property, etc. On the other hand, the content of polymer (2) in layer (B) is less than 99% by mass. The upper limit of this content may be 98% by mass, or may be 97%, 96%, or 95% by mass.

[0065] (Layered inorganic compound (X)) The layer (B) contains a layered inorganic compound (X) having an aspect ratio of 50 or more. When the layer (B) contains an appropriate amount of the layered inorganic compound (X), the smoothness of the layer (B) and the vapor-deposited layer (C) formed on this layer (B) is improved, and the water vapor barrier property and oxygen barrier property can be improved.

[0066] Examples of the layered inorganic compound (X) include the same compounds as those exemplified as the layered inorganic compounds among the inorganic compounds (Y) in the description of the precoat layer (A). One or more types of the layered inorganic compound (X) can be used.

[0067] The average particle size of the layered inorganic compound (X) is preferably from 1 μm to 50 μm, more preferably from 4 μm to 30 μm. When the average particle size of the layered inorganic compound (X) is within the above range, the water vapor barrier property, oxygen barrier property, etc. can be further improved.

[0068] The aspect ratio of the layered inorganic compound (X) is preferably 80 or more, more preferably 150 or more, and even more preferably 200 or more. When the aspect ratio is equal to or greater than the lower limit, the content of the layered inorganic compound (X) necessary to exhibit sufficient barrier properties is reduced, and the surface of the layer (B) tends to be smooth. Therefore, when the aspect ratio is equal to or greater than the lower limit, the state of the vapor-deposited layer (C) tends to be good, and the oxygen barrier property and water vapor barrier property tend to be excellent. The aspect ratio may be, for example, 10,000 or less, 7,000 or less, 3,000 or less, or 1,000 or less.

[0069] The lower limit of the content of the layered inorganic compound (X) in the layer (B) is 1% by mass, preferably 2% by mass, more preferably 3% by mass, and even more preferably 4% by mass. By making the content of the layered inorganic compound (X) in the layer (B) equal to or greater than the above-mentioned lower limit, the water vapor barrier property and oxygen barrier property can be improved. On the other hand, the content of the layered inorganic compound (X) in the layer (B) is less than 50% by mass. If the content of the layered inorganic compound (X) in the layer (B) is 50% by mass or more, the smoothness of the layer (B) decreases, and defects occur in the vapor-deposited layer (C), which in turn reduces the water vapor barrier property and oxygen barrier property. The upper limit of the content is preferably 40% by mass, more preferably 30% by mass, even more preferably 20% by mass, and even more preferably 10% by mass. Furthermore, the lower limit of the content of the layered inorganic compound (X) relative to 100 parts by mass of the polymer (2) in the layer (B) is preferably 2 parts by mass, more preferably 3 parts by mass, and may be 4 parts by mass or 5 parts by mass. On the other hand, the upper limit of this content is preferably 80 parts by mass, more preferably 60 parts by mass, and even more preferably 40 parts by mass, and may be 30 parts by mass or 20 parts by mass.

[0070] (Other Components, etc.) The layer (B) may further contain other components in addition to the polymer (2) and the layered inorganic compound (X). Examples of other components include resins other than the polymer (2), dispersants, surfactants, antifoaming agents, dyes, preservatives, fillers, interlayer adhesives, thickeners, etc. However, the total content of the polymer (2) and the layered inorganic compound (X) in the layer (B) is preferably 90% by mass or more, more preferably 95% by mass or more, or more preferably 99% by mass or more.

[0071] The mass per unit area of ​​one layer (B) is 0.3 g / m ２ 15g / m or more ２ Preferably, 0.5 g / m or less ２ 10g / m or more ２ More preferably, 1 g / m or less ２ 6g / m or more ２ More preferably, 1.5 g / m or less ２ 4.0g / m or more ２ The following is even more preferable. When the mass per unit area of ​​one layer (B) is equal to or greater than the above lower limit, the water vapor barrier property, oxygen barrier property, etc. can be further improved. On the other hand, when the mass per unit area of ​​one layer (B) is equal to or less than the above upper limit, the laminate can be made thinner. Furthermore, when the mass per unit area of ​​one layer (B) is equal to or less than the above upper limit, cracking of the layer (B) during bending, etc., can be suppressed, and deterioration of the water vapor barrier property and oxygen barrier property after bending can be reduced.

[0072] (Vapor-deposited layer (C)) The vapor-deposited layer (C) is a layer located on the opposite side of the layer (B) to the precoat layer (A). The vapor-deposited layer (C) may be a layer directly laminated on the layer (B). From the viewpoint of reducing the thickness of the laminate, it is preferable that no other layer is present between the vapor-deposited layer (C) and the layer (B). The vapor-deposited layer (C) is a layer formed by vapor deposition, and is preferably a layer formed by vapor deposition of an inorganic substance (inorganic vapor-deposited layer). By including the vapor-deposited layer (C), the laminate can exhibit excellent water vapor barrier properties, oxygen barrier properties, etc.

[0073] Examples of materials constituting the vapor-deposited layer (C) include inorganic materials such as metals (e.g., aluminum), metal oxides (e.g., silicon oxide, aluminum oxide, magnesium oxide), metal nitrides (e.g., silicon nitride), metal nitride oxides (e.g., silicon oxynitride), and metal carbonitrides (e.g., silicon carbonitride). Among the above examples of inorganic materials, silicon is considered to be included in the metals. The vapor-deposited layer (C) may be composed of an organic material, or may be composed of both an organic material and an inorganic material. From the viewpoints of barrier properties, industrial productivity, and the like, the material constituting the vapor-deposited layer (C) is preferably aluminum, aluminum oxide, silicon oxide, magnesium oxide, or silicon nitride, more preferably aluminum or aluminum oxide, and even more preferably aluminum.

[0074] The lower limit of the average thickness of one vapor-deposited layer (C) is preferably 5 nm, more preferably 10 nm, even more preferably 20 nm, and even more preferably 30 nm. By setting the average thickness of the vapor-deposited layer (C) to the above-mentioned lower limit or more, it is possible to improve the barrier properties, etc. On the other hand, the upper limit of the average thickness of one vapor-deposited layer (C) is preferably 200 nm, more preferably 150 nm, even more preferably 100 nm, and may be 80 nm or 60 nm. By setting the average thickness of the vapor-deposited layer (C) to the above-mentioned upper limit or less, cracking of the vapor-deposited layer (C) during bending, etc., can be suppressed, and deterioration of the water vapor barrier property and oxygen barrier property after bending can be reduced. The average thickness of the vapor-deposited layer (C) is the average value of the thicknesses at any 10 points on the cross section of the vapor-deposited layer (C) measured using an electron microscope.

[0075] (Heat seal layer (D)) The laminate according to one embodiment of the present invention preferably further comprises a heat seal layer (D). The heat seal layer (D) is usually the outermost layer of the laminate. That is, the laminate according to one embodiment of the present invention may have a heat seal layer (D) on the outermost surface. The "outermost surface" refers to the exposed surface other than the end faces, and does not mean to distinguish between the front and back of the laminate. That is, the laminate has two outermost surfaces. The heat seal layer (D) is preferably located on the outermost surface on the vapor deposition layer (C) side of the paper substrate. The outermost layers on both sides of the laminate may both be heat seal layers (D). The heat seal layer (D) may be a layer formed by coating (coating layer).

[0076] The heat seal layer (D) usually contains a polymer. The polymer is preferably the main component of the heat seal layer (D). The polymer used in the heat seal layer (D) is preferably a thermoplastic resin. The melting point of the polymer used in the heat seal layer (D) is preferably 50°C or higher and 140°C or lower, more preferably 70°C or higher and 110°C or lower. One or more types of polymers can be used.

[0077] (Polymer (3)) The polymer used in the heat seal layer (D) is preferably at least one polymer (3) selected from the group consisting of an olefin polymer, a styrene polymer, and a polyester polymer. Specific and preferred embodiments of these polymers (3) are the same as those of the olefin polymer, the styrene polymer, and the polyester polymer described above as polymer (1). One or more types of polymer (3) can be used.

[0078] As the polymer (3), at least one selected from the group consisting of an olefin polymer and a styrene polymer is preferred, and in some cases a styrene polymer is more preferred. As the polymer (3), an olefin polymer is more preferred. As the olefin polymer as the polymer (3), an olefin-vinyl ester copolymer or an olefin-unsaturated carboxylic acid copolymer is preferred, an olefin-unsaturated carboxylic acid copolymer is more preferred, an olefin-unsaturated carboxylic acid copolymer is even more preferred, and an ethylene-(meth)acrylic acid copolymer is even more preferred. As the styrene copolymer as the polymer (3), a styrene-acrylic copolymer is preferred.

[0079] The lower limit of the content of polymer (3) in the heat seal layer (D) is preferably 50% by mass, more preferably 60% by mass, even more preferably 70% by mass, and even more preferably 80% by mass or 85% by mass. By setting the content of polymer (3) to the above lower limit or more, it is possible to improve the heat sealability, etc. On the other hand, the upper limit of this content is preferably 100% by mass, and may be 99% by mass or 95% by mass.

[0080] (Vinyl Alcohol-Based Polymer) The heat-seal layer (D) preferably contains a vinyl alcohol-based polymer. When the heat-seal layer (D) contains a vinyl alcohol-based polymer, the smoothness of the surface of the heat-seal layer (D) can be increased. Furthermore, when the heat-seal layer (D) contains a vinyl alcohol-based polymer, the water vapor barrier property and oxygen barrier property of the laminate can be further improved. The heat-seal layer (D) more preferably contains a vinyl alcohol-based polymer together with the polymer (3), and even more preferably contains a vinyl alcohol-based polymer together with an olefin-based polymer (particularly an ethylene-(meth)acrylic acid copolymer) or a styrene-based polymer (particularly a styrene-acrylic copolymer).

[0081] The specific form of the vinyl alcohol polymer contained in the heat seal layer (D) is the same as the specific form of the vinyl alcohol polymer as the polymer (1) described above. One or more types of vinyl alcohol polymers can be used.

[0082] The viscosity-average degree of polymerization of the vinyl alcohol polymer contained in the heat-seal layer (D) is preferably 200 or more and 5,000 or less. The lower limit of the viscosity-average degree of polymerization may be 300 or 400. On the other hand, the upper limit of the viscosity-average degree of polymerization may be 3,000, 2,500, 2,000, 1,200, 800, or 600. When the viscosity-average degree of polymerization of the vinyl alcohol polymer contained in the heat-seal layer (D) is within the above range, the water vapor barrier property, oxygen barrier property, etc. can be further improved, and the coatability and strength of the layer formed can also be optimized.

[0083] The lower limit of the saponification degree of the vinyl alcohol polymer contained in the heat seal layer (D) is preferably 60 mol%, more preferably 70 mol%, more preferably 80 mol%, and even more preferably 84 mol%. On the other hand, the upper limit of the saponification degree may be 100 mol%, but is preferably 98 mol%, more preferably 95 mol%, and even more preferably 92 mol%. When the saponification degree of the vinyl alcohol polymer contained in the heat seal layer (D) is within the above range, it is possible to further improve the water vapor barrier property, etc.

[0084] The total content of vinyl alcohol units and vinyl ester units relative to all monomer units of the vinyl alcohol polymer contained in the heat seal layer (D) is preferably 95 mol % or more, more preferably 99 mol % or more, and may be 100 mol %.

[0085] When the heat-seal layer (D) contains the polymer (3) and a vinyl alcohol-based polymer, the lower limit of the content of the vinyl alcohol-based polymer in the heat-seal layer (D) is preferably 1 part by mass, more preferably 3 parts by mass, even more preferably 5 parts by mass, and even more preferably 7 parts by mass, per 100 parts by mass of the polymer (3), while the upper limit of this content is preferably 50 parts by mass, more preferably 30 parts by mass, even more preferably 20 parts by mass, and even more preferably 15 parts by mass, per 100 parts by mass of the polymer (3).

[0086] When the heat seal layer (D) contains a vinyl alcohol polymer, the lower limit of the content of the vinyl alcohol polymer in the heat seal layer (D) is preferably 1% by mass, more preferably 3% by mass, even more preferably 5% by mass, and even more preferably 7% by mass, while the upper limit of this content is preferably 50% by mass, more preferably 30% by mass, even more preferably 20% by mass, and even more preferably 15% by mass.

[0087] The total content of the polymer (3) and the vinyl alcohol polymer in the heat seal layer (D) is preferably 90% by mass or more, more preferably 95% by mass or more, and may be 99% by mass or more.

[0088] The heat seal layer (D) may further contain components other than the above-mentioned polymers, such as wax (e.g., paraffin wax), dispersants, surfactants, antifoaming agents, dyes, and thickeners.

[0089] The mass per unit area of ​​one heat seal layer (D) is 1 g / m ２ 50g / m or more ２ Preferably, 2 g / m or less ２ 30g / m or more ２ More preferably, 3 g / m or less ２ 20g / m or more ２ More preferably, 4 g / m or less ２ 15g / m or more ２ Even more preferably, ２ 10g / m or more ２ The following is particularly preferred. When the mass per unit area of ​​one heat seal layer (D) is not less than the above lower limit, sufficient heat sealability can be exhibited and the water vapor barrier property, oxygen barrier property, etc. can be further improved. On the other hand, when the mass per unit area of ​​one heat seal layer (D) is not more than the above upper limit, the laminate can be made thinner, etc.

[0090] (Other Layers, Layer Structure, etc.) The laminate according to one embodiment of the present invention may further have layers other than the paper substrate, precoat layer (A), layer (B), vapor-deposited layer (C), and heat-seal layer (D). Examples of other layers include other resin layers, metal foil layers, etc. In one embodiment of the present invention, the laminate does not necessarily have layers other than the paper substrate, precoat layer (A), layer (B), vapor-deposited layer (C), and heat-seal layer (D).

[0091] In a laminate according to one embodiment of the present invention, the paper substrate, the precoat layer (A), the layer (B), the vapor-deposited layer (C), and the heat-seal layer (D) may each be a single layer or two or more layers. In a laminate according to one embodiment of the present invention, the paper substrate, the precoat layer (A), the layer (B), the vapor-deposited layer (C), and the heat-seal layer (D) are each preferably a single layer. When there are two or more layers of any of the paper substrate, the precoat layer (A), the layer (B), the vapor-deposited layer (C), and the heat-seal layer (D), their compositions, thicknesses, etc. may be the same or different.

[0092] Examples of the layer structure of the laminate according to one embodiment of the present invention are as follows: A represents the precoat layer (A), B represents the layer (B), C represents the vapor deposition layer (C), D represents the heat seal layer (D), and E represents other layers. Paper substrate / A / B / C Paper substrate / A / B / C / D Paper substrate / A / B / C / E / D D / Paper substrate / A / B / C D / Paper substrate / A / B / C / D E / Paper substrate / A / B / C E / Paper substrate / A / B / C / D D / C / B / A / Paper substrate / A / B / C / D

[0093] The laminate according to one embodiment of the present invention can be suitably used as greaseproof paper, gas barrier paper, flavor barrier paper, packaging material, etc. When the laminate has a heat seal layer (D), it can also be used in a state where it has been formed into a predetermined shape (for example, a bag shape) by heat sealing the heat seal layers (D) together. The heat sealing method is not particularly limited, and known methods can be used, and heat sealing can be performed using, for example, a hot plate heat sealer, an impulse sealer, an ultrasonic sealer, a frictional heat sealer, a dielectric heating sealer, etc.

[0094] <Method for producing laminate> The method for producing a laminate according to one embodiment of the present invention is not particularly limited, but it can typically be produced by providing a precoat layer (A) and a layer (B) in this order on a paper substrate by coating, and then providing a vapor-deposited layer (C) on layer (B) by vapor deposition. In the case of a laminate having a heat-sealing layer (D), the heat-sealing layer (D) can also be provided by coating. The heat-sealing layer (D) may also be provided by a method other than coating.

[0095] For example, the precoat layer (A), layer (B), and heat seal layer (D) can be provided by applying and drying a coating liquid for forming each layer. Drying does not need to be performed after each coating liquid, and a simultaneous multi-layer coating method may be employed. The coating of each coating liquid can be carried out by a conventionally known method. Coating can be carried out using, for example, a blade coater, a flexo coater, a comma coater, a metering rod size press, a two-roll size press, a shim sizer, a bar coater, an air knife coater, a slit die coater, a gravure coater, a reverse gravure coater, a microgravure coater, a gate roll coater, a curtain coater, or the like.

[0096] The method for drying the applied coating liquid is not particularly limited, and can be carried out using, for example, a hot air dryer, an infrared dryer, a gas burner, a hot plate, or the like.

[0097] The solvent or dispersion medium for the coating liquid for forming each layer is not particularly limited, and water or an organic solvent (ethanol, isopropyl alcohol, methyl ethyl ketone, toluene, etc.) can be used, with water being preferred.

[0098] The deposition layer (C) can be formed by a known deposition method such as vacuum deposition, sputtering, ion plating, or chemical vapor deposition (CVD).

[0099] <Grease-resistant paper> Grease-resistant paper including the laminate according to one embodiment of the present invention is also a suitable embodiment of the present invention. The grease-resistant paper according to one embodiment of the present invention may be made of the laminate according to one embodiment of the present invention.

[0100] The greaseproof paper has excellent water vapor barrier properties and oxygen barrier properties, and is suitable for use as packaging for oily foods such as French fries and fried chicken, packaging for wrapping butter, and cooking paper for baking bread, cakes, and the like.

[0101] The oil resistance (KIT value) of the greaseproof paper is preferably at least grade 5, and more preferably at least grade 6 or at least grade 7. This oil resistance is a value measured on the surface by a kit test based on TAPPI No. T559cm-02.

[0102] <Gas barrier paper> A gas barrier paper comprising a laminate according to one embodiment of the present invention is also a suitable embodiment of the present invention. The gas barrier paper according to one embodiment of the present invention may be made of the laminate according to one embodiment of the present invention.

[0103] The gas barrier paper has excellent water vapor barrier properties and oxygen barrier properties and is suitable for use as packaging material for food, pesticides, chemicals, cosmetics, medical supplies, electronic components, clothing, and the like.

[0104] The oxygen permeability of the gas barrier paper measured under conditions of 23°C and 65% RH is 5 cc / atm / m ２ / day or less is preferable, and 3 cc / atm / m ２ / day or less is more preferable, and 1 cc / atm / m ２ / day or less is more preferable.

[0105] <Packaging Material> A packaging material including a laminate according to one embodiment of the present invention is also a suitable embodiment of the present invention. The packaging material according to one embodiment of the present invention may be made of the laminate according to one embodiment of the present invention, the greaseproof paper according to one embodiment of the present invention, or the gas barrier paper according to one embodiment of the present invention.

[0106] The packaging material has excellent water vapor barrier properties and oxygen barrier properties and is suitable for use as packaging for, for example, food, agricultural chemicals, pharmaceuticals, cosmetics, medical products, electronic components, clothing, and the like.

[0107] The present invention will be explained in more detail below using examples, but the present invention is not limited to these examples in any way.

[0108] (Evaluation of Water Vapor Barrier Property) The water vapor transmission rate (WVTR) of the laminate was measured by the cup method in accordance with JIS Z 2080 under conditions of a temperature of 40° C. and a relative humidity of 90%, with the coated surface facing inward.

[0109] (Evaluation of oxygen barrier property) The oxygen transmission rate (OTR) of the laminate was measured using an oxygen transmission rate measuring device (OX-TRAN2 / 20, manufactured by MOCON Corporation) under conditions of 23°C and 65% RH. In addition, the oxygen transmission rate (OTR) of the laminates of Examples 13 to 16 was also measured using an oxygen transmission rate measuring device (OX-TRAN2 / 20, manufactured by MOCON Corporation) under conditions of 23°C and 90% RH.

[0110] Example 1 A dispersion of ethylene-acrylic acid copolymer ("Zaixen AC" manufactured by Mitsui Chemicals, Inc.) as polymer (1) was prepared as coating liquid (A) for forming precoat layer (A). Ethylene-modified polyvinyl alcohol (PVOH-2) with a viscosity-average degree of polymerization of 300, a degree of saponification of 99.0 mol%, and an ethylene modification amount of 7.0 mol% was used as polymer (2), and a layered inorganic compound (ME300B-4T" manufactured by Katakura Co-op Agri Co., Ltd.) with an aspect ratio of approximately 300 was used as layered inorganic compound (X). Coating liquid (B) for forming layer (B) was obtained by mixing layered inorganic compound (X) with a 12% by mass aqueous solution of ethylene-modified polyvinyl alcohol. The content of layered inorganic compound (X) in coating liquid (B) was 5 parts by mass per 100 parts by mass of ethylene-modified polyvinyl alcohol. A dispersion of ethylene-acrylic acid copolymer ("Zaixen AC" manufactured by Mitsui Chemicals, Inc.) as polymer (3) was prepared as a coating liquid (D) for forming the heat seal layer (D).

[0111] Basis weight as paper base material: 80 g / m ２ The coating weight after drying was 9 g / m on bleached kraft paper. ２ The coating solution (A) was applied to the substrate using a Ribar gravure coater so that the coating density was 2 g / m2 (gsm), and the coating solution (A) was dried at 100°C for 5 minutes to form a precoat layer (A). ２The coating solution (B) was applied using a reverse gravure coater so that the coating temperature was 100°C for 5 minutes, and the coating solution (B) was then dried. Subsequently, an aluminum vapor-deposited layer having an average thickness of about 40 nm was formed as a vapor-deposited layer (C). Furthermore, an aluminum vapor-deposited layer having an average coating weight of 6 g / m2 was formed on the vapor-deposited layer (C) so that the coating temperature was 100°C for 5 minutes, and the coating weight was 6 g / m2. ２ The coating liquid (D) was applied using a wire bar so as to form a heat seal layer (D), which was then dried at 100° C. for 5 minutes.

[0112] The surface of the obtained laminate of Example 1 (the surface of the heat seal layer (D)) was rough and the surface smoothness was insufficient, but the water vapor barrier property (WVTR) was 4 cc / m ２ / day, oxygen barrier resistance (OTR) under conditions of 23°C and 65% RH is 0.1 cc / atm / m ２ / day, and the film had excellent water vapor barrier properties and oxygen barrier properties.

[0113] [Example 2] A laminate was produced in the same manner as in Example 1, except that the heat seal layer (D) was not provided. The water vapor barrier property (WVTR) of the obtained laminate of Example 2 was 17 cc / m ２ / day, oxygen barrier resistance (OTR) under conditions of 23°C and 65% RH is 0.1 cc / atm / m ２ / day, and the film had excellent water vapor barrier properties and oxygen barrier properties.

[0114] [Example 3] A laminate was produced in the same manner as in Example 1, except that the polymer (2) was changed to polyvinyl alcohol (PVOH-3) having a viscosity-average degree of polymerization of 1,000 and a degree of saponification of 98.0 mol%. The surface of the obtained laminate of Example 3 (the surface of the heat seal layer (D)) was rough and the surface smoothness was insufficient, but the water vapor barrier property (WVTR) was 4 cc / m ２ / day, oxygen barrier resistance (OTR) under conditions of 23°C and 65% RH is 0.1 cc / atm / m ２ / day, and the film had excellent water vapor barrier properties and oxygen barrier properties.

[0115] [Example 4] A laminate was produced in the same manner as in Example 3, except that the content of the layered inorganic compound (X) in the coating liquid (B) was 15 parts by mass relative to 100 parts by mass of polyvinyl alcohol. The surface of the obtained laminate of Example 4 (the surface of the heat seal layer (D)) was rough and the surface smoothness was insufficient, but the water vapor barrier property (WVTR) was 4 cc / m ２ / day, oxygen barrier resistance (OTR) under conditions of 23°C and 65% RH is 0.1 cc / atm / m ２ / day, and the film had excellent water vapor barrier properties and oxygen barrier properties.

[0116] [Example 5] A laminate was produced in the same manner as in Example 1, except that a heat seal layer (D) was provided using a dispersion of a styrene-acrylic copolymer ("SEIKOAT (registered trademark) XP8829" manufactured by Seiko PMC Corporation) as the polymer (3) as the coating liquid (D). The obtained laminate of Example 5 had a water vapor barrier property (WVTR) of 18 cc / m ２ / day, oxygen barrier resistance (OTR) under conditions of 23°C and 65% RH is 0.1 cc / atm / m ２ / day, and the film had excellent water vapor barrier properties and oxygen barrier properties.

[0117] Example 6 A coating liquid (A) for forming a precoat layer (A) having a solids content of 10% by mass was prepared using ethylene-modified polyvinyl alcohol (PVOH-1) as polymer (1) having a viscosity-average degree of polymerization of 1,000, a degree of saponification of 99.4 mol%, and an ethylene modification amount of 4.0 mol%, and an inorganic compound (Y) having an aspect ratio of approximately 30 ("FinnTalc C15B" manufactured by ELEMENTIS). The content of inorganic compound (Y) in coating liquid (A) was 60 parts by mass relative to 100 parts by mass of the ethylene-modified polyvinyl alcohol. Using ethylene-modified polyvinyl alcohol (PVOH-4) having a viscosity-average degree of polymerization of 1,900, a degree of saponification of 97.6 mol%, and an ethylene modification amount of 3.0 mol% as the polymer (2), and a layered inorganic compound having an aspect ratio of approximately 100 ("ME100B-4T" manufactured by Katakura Co-op Agri Co., Ltd.) as the layered inorganic compound (X), the layered inorganic compound (X) was mixed with an 8% by mass aqueous solution of ethylene-modified polyvinyl alcohol to obtain a coating liquid (B) for forming layer (B). The content of the layered inorganic compound (X) in the coating liquid (B) was 5 parts by mass per 100 parts by mass of the ethylene-modified polyvinyl alcohol. A dispersion of ethylene-acrylic acid copolymer ("Zaixen AC" manufactured by Mitsui Chemicals, Inc.) as the polymer (3) was prepared as a coating liquid (D) for forming the heat-seal layer (D).

[0118] Basis weight as paper base material: 80 g / m ２ The coating weight after drying was 2 g / m on bleached kraft paper. ２ The coating solution (A) was applied using a wire bar so that the coating amount after drying was 2 g / m. ２ The coating solution (B) was applied using a wire bar so that the coating amount after drying was 6 g / m², and the coating solution was dried at 100°C for 5 minutes to form a layer (B). Then, an aluminum vapor-deposited layer having an average thickness of about 40 nm was formed on the layer (B) as a vapor-deposited layer (C). Furthermore, an aluminum vapor-deposited layer having an average thickness of about 40 nm was formed on the vapor-deposited layer (C) so that the coating amount after drying was 6 g / m². ２ The coating liquid (D) was applied using a wire bar so that the thickness of the coated film was as follows: and the coated film was dried at 100° C. for 5 minutes to provide a heat seal layer (D).

[0119] The surface of the obtained laminate of Example 6 (the surface of the heat seal layer (D)) was rough and the surface smoothness was insufficient, but the water vapor barrier property (WVTR) was 25 cc / m ２ / day, oxygen barrier resistance (OTR) under conditions of 23°C and 65% RH is 0.1 cc / atm / m ２ / day, and the film had excellent water vapor barrier properties and oxygen barrier properties.

[0120] Example 7 A dispersion of an ethylene-acrylic acid copolymer ("Zaixen AC" manufactured by Mitsui Chemicals, Inc.) as the polymer (1) and a layered inorganic compound ("ME300B-4T" manufactured by Katakura Co-op Agri Co., Ltd.) as the inorganic compound (Y) were mixed at a mass ratio of 100 / 5 in terms of solid content to obtain a coating liquid (A) for forming a precoat layer (A). A dispersion of an ethylene-acrylic acid copolymer ("Zaixen AC" manufactured by Mitsui Chemicals, Inc.) as the polymer (3) and polyvinyl alcohol (PVOH-8) having a viscosity average degree of polymerization of 430 and a degree of saponification of 98.2 mol% were mixed at a mass ratio of 90 / 10 in terms of solid content to obtain a coating liquid (D) for forming a heat seal layer (D).

[0121] Basis weight as paper base material: 80 g / m ２ The coating weight after drying was 10 g / m on bleached kraft paper. ２ The coating solution (A) was applied using a wire bar so that the coating thickness was 100°C for 5 minutes, and the coating solution (A) was then dried at 100°C for 5 minutes to provide a precoat layer (A). Next, in the same manner as in Example 1, a layer (B) and a vapor-deposited layer (C) were provided. Furthermore, a layer (B) and a vapor-deposited layer (C) were provided on the vapor-deposited layer (C) so that the coating amount after drying was 6 g / m. ２ The coating liquid (D) was applied using a wire bar so as to form a heat seal layer (D), which was then dried at 100° C. for 5 minutes.

[0122] The surface of the obtained laminate of Example 7 (the surface of the heat seal layer (D)) was smooth. The water vapor barrier property (WVTR) of the laminate of Example 7 was 3 cc / m ２ / day, oxygen barrier resistance (OTR) under conditions of 23°C and 65% RH is 0.1 cc / atm / m ２ / day, and the film had excellent water vapor barrier properties and oxygen barrier properties.

[0123] Example 8 A dispersion of a styrene-acrylic copolymer ("Joncryl 4020" manufactured by BASF) as polymer (3) and polyvinyl alcohol (PVOH-9) having a viscosity average degree of polymerization of 500 and a degree of saponification of 88.2 mol% were mixed in a ratio of 9 / 1 in terms of solid content to prepare a coating liquid (D) for forming a heat seal layer (D). A laminate was produced in the same manner as in Example 7, except that the heat seal layer (D) was provided using this coating liquid (D). The surface of the obtained laminate of Example 8 (surface of the heat seal layer (D)) was smooth. The water vapor barrier property (WVTR) of the laminate of Example 8 was 1 cc / m ２ / day, oxygen barrier resistance (OTR) under conditions of 23°C and 65% RH is 0.1 cc / atm / m ２ / day, and the film had excellent water vapor barrier properties and oxygen barrier properties.

[0124] [Example 9] A laminate was produced in the same manner as in Example 8, except that ethylene-modified polyvinyl alcohol (PVOH-1) having a viscosity-average degree of polymerization of 1,000, a degree of saponification of 99.4 mol%, and an ethylene modification amount of 4.0 mol% was used as the polymer (2). The surface of the obtained laminate of Example 9 (the surface of the heat seal layer (D)) was smooth. The water vapor barrier property (WVTR) of the laminate of Example 9 was 1 cc / m ２ / day, oxygen barrier resistance (OTR) under conditions of 23°C and 65% RH is 0.1 cc / atm / m ２ / day, and the film had excellent water vapor barrier properties and oxygen barrier properties.

[0125] [Example 10] A laminate was produced in the same manner as in Example 8, except that polyvinyl alcohol (PVOH-5) having a viscosity average degree of polymerization of 610 and a degree of saponification of 96.0 mol% was used as the polymer (2). The surface of the obtained laminate of Example 10 (the surface of the heat seal layer (D)) was smooth. The water vapor barrier property (WVTR) of the laminate of Example 10 was 1 cc / m ２ / day, oxygen barrier resistance (OTR) under conditions of 23°C and 65% RH is 0.1 cc / atm / m ２ / day, and the film had excellent water vapor barrier properties and oxygen barrier properties.

[0126] Example 11 A laminate was produced in the same manner as in Example 2, except that a vinyl alcohol polymer (PVOH-6, Selvol (registered trademark) Ultiloc 5003, manufactured by Sekisui Chemical Co., Ltd.) was used as the polymer (2). The water vapor barrier property (WVTR) of the obtained laminate of Example 11 was 8 cc / m ２ / day, oxygen barrier resistance (OTR) under conditions of 23°C and 65% RH is 0.1 cc / atm / m ２ / day, and the film had excellent water vapor barrier properties and oxygen barrier properties.

[0127] [Example 12] A laminate was produced in the same manner as in Example 2, except that a vinyl alcohol polymer ("Nichigo G Polymer (registered trademark) BVE8049Q" manufactured by Mitsubishi Chemical Corporation) (PVOH-7) was used as the polymer (2). The water vapor barrier property (WVTR) of the obtained laminate of Example 12 was 8 cc / m ２ / day, oxygen barrier resistance (OTR) under conditions of 23°C and 65% RH is 0.1 cc / atm / m ２ / day, and the film had excellent water vapor barrier properties and oxygen barrier properties.

[0128] [Example 13] A laminate was produced in the same manner as in Example 2, except that PVOH-4 was used as the polymer (2) and the content of the layered inorganic compound (X) in the coating liquid (B) was 3 parts by mass per 100 parts by mass of polyvinyl alcohol. The water vapor barrier property (WVTR) of the obtained laminate of Example 13 was 20 cc / m ２ / day, oxygen barrier resistance (OTR) under conditions of 23°C and 65% RH is 0.1 cc / atm / m ２ / day, oxygen barrier resistance (OTR) under conditions of 23°C and 90% RH is 1.3 cc / atm / m ２ / day, and the film had excellent water vapor barrier properties and oxygen barrier properties.

[0129] Example 14 A laminate was produced in the same manner as in Example 13, except that a layered inorganic compound having an aspect ratio of about 100 ("ME100B-4T" manufactured by Katakura Co-op Agri Co., Ltd.) was used as the layered inorganic compound (X). The water vapor barrier property (WVTR) of the obtained laminate of Example 14 was 18 cc / m２ / day, oxygen barrier resistance (OTR) under conditions of 23°C and 65% RH is 0.1 cc / atm / m ２ / day, oxygen barrier resistance (OTR) under conditions of 23°C and 90% RH is 0.9 cc / atm / m ２ / day, and the film had excellent water vapor barrier properties and oxygen barrier properties.

[0130] [Example 15] A laminate was produced in the same manner as in Example 14, except that the content of the layered inorganic compound (X) in the coating liquid (B) was 20 parts by mass relative to 100 parts by mass of polyvinyl alcohol. The water vapor barrier property (WVTR) of the obtained laminate of Example 15 was 16 cc / m ２ / day, oxygen barrier resistance (OTR) under conditions of 23°C and 65% RH is 0.1 cc / atm / m ２ / day, oxygen barrier resistance (OTR) under conditions of 23°C and 90% RH is 0.3 cc / atm / m ２ / day, and the film had excellent water vapor barrier properties and oxygen barrier properties.

[0131] [Example 16] A laminate was produced in the same manner as in Example 13, except that the content of the layered inorganic compound (X) in the coating liquid (B) was 50 parts by mass relative to 100 parts by mass of polyvinyl alcohol. The water vapor barrier property (WVTR) of the obtained laminate of Example 15 was 35 cc / m ２ / day, oxygen barrier resistance (OTR) under conditions of 23°C and 65% RH is 0.1 cc / atm / m ２ / day, oxygen barrier resistance (OTR) under conditions of 23°C and 90% RH is 2.3 cc / atm / m ２ / day, and the film had excellent water vapor barrier properties and oxygen barrier properties.

[0132] [Comparative Example 1] A laminate was produced in the same manner as in Example 5, except that the vapor-deposited layer (C) was not provided. The water vapor barrier property (WVTR) of the obtained laminate of Comparative Example 1 was 21 cc / m ２ / day, oxygen barrier resistance (OTR) under conditions of 23°C and 65% RH is 1.1 cc / atm / m ２ / day.

[0133] [Comparative Example 2] A laminate was produced in the same manner as in Example 5, except that the layer (B) was not provided. The water vapor barrier property (WVTR) of the obtained laminate of Comparative Example 2 was 25 cc / m ２ / day, oxygen barrier resistance (OTR) under conditions of 23°C and 65% RH is 5cc / atm / m ２ It was over / day.

[0134] [Comparative Example 3] A laminate was produced in the same manner as in Example 2, except that the content of the layered inorganic compound (X) in the coating liquid (B) was 120 parts by mass per 100 parts by mass of ethylene-modified polyvinyl alcohol. The water vapor barrier property (WVTR) of the obtained laminate of Comparative Example 3 was 38 cc / m ２ / day, oxygen barrier resistance (OTR) under conditions of 23°C and 65% RH is 5cc / atm / m ２ It was over / day.

[0135] [Comparative Example 4] A laminate was produced in the same manner as in Example 2, except that the layered inorganic compound (X) was not blended into the coating liquid (B). The water vapor barrier property (WVTR) of the obtained laminate of Comparative Example 4 was 8 cc / m ２ / day, oxygen barrier resistance (OTR) under conditions of 23°C and 65% RH is 0.2 cc / atm / m ２ / day.

[0136] The results of the above-mentioned Examples and Comparative Examples are shown in Table 1. The components listed in Table 1 are as follows. EAA: Ethylene-acrylic acid copolymer (Zaixen AC) SA-1: Styrene-acrylic copolymer (SEIKOAT XP8829) SA-2: Styrene-acrylic copolymer (Joncryl 4020) PVOH-1: Ethylene-modified polyvinyl alcohol having a viscosity average degree of polymerization of 1,000, a degree of saponification of 99.4 mol%, and an ethylene modification amount of 4.0 mol% PVOH-2: Ethylene-modified polyvinyl alcohol having a viscosity average degree of polymerization of 300, a degree of saponification of 99.0 mol%, and an ethylene modification amount of 7.0 mol% PVOH-3: Polyvinyl alcohol having a viscosity average degree of polymerization of 1,000, and a degree of saponification of 98.0 mol% PVOH-4: Ethylene-modified polyvinyl alcohol having a viscosity average degree of polymerization of 1,900, a degree of saponification of 97.6 mol%, and an ethylene modification amount of 3.0 mol% PVOH-5: Polyvinyl alcohol having a viscosity average degree of polymerization of 610, and a degree of saponification of 96.0 mol% PVOH-6: vinyl alcohol polymer "Selvol Ultiloc 5003" manufactured by Sekisui Chemical Co., Ltd. PVOH-7: vinyl alcohol polymer ("BVE8049Q" manufactured by Mitsubishi Chemical Corporation) PVOH-8: polyvinyl alcohol with a viscosity average degree of polymerization of 430 and a degree of saponification of 98.2 mol% PVOH-9: polyvinyl alcohol with a viscosity average degree of polymerization of 500 and a degree of saponification of 88.2 mol% AS30: inorganic compound with an aspect ratio of approximately 30 (FinnTalc C15B) AS100: layered inorganic compound with an aspect ratio of approximately 100 (ME100B-4T) AS300: layered inorganic compound with an aspect ratio of approximately 300 (ME300B-4T)

[0137]

[0138] Each of the laminates of Examples 1 to 16 had excellent water vapor barrier properties and oxygen barrier properties.

[0139] The laminate of the present invention can be suitably used as a packaging material such as greaseproof paper, gas barrier paper, and flavor barrier paper.

Claims

1. A laminate having a precoat layer (A), a layer (B), and a vapor-deposited layer (C) on a paper substrate in this order, wherein the precoat layer (A) contains at least one polymer (1) selected from the group consisting of water-soluble polymers and water-dispersible polymers, the layer (B) contains 50% by mass or more and less than 99% by mass of at least one polymer (2) selected from the group consisting of water-soluble polymers and water-dispersible polymers, and the layer (B) contains 1% by mass or more and less than 50% by mass of a layered inorganic compound (X) having an aspect ratio of 50 or more.

2. The laminate according to claim 1, wherein the polymer (1) is at least one selected from the group consisting of olefin polymers, styrene polymers, polyester polymers, urethane polymers, and vinyl alcohol polymers.

3. The laminate according to claim 1 or 2, wherein the content of the polymer (1) in the precoat layer (A) is 50% by mass or more and less than 99% by mass.

4. The laminate according to claim 1 or 2, wherein the precoat layer (A) contains 1% by mass or more and less than 50% by mass of the inorganic compound (Y).

5. The laminate according to claim 4, wherein the inorganic compound (Y) is a layered inorganic compound having an aspect ratio of 200 or more.

6. The laminate according to claim 1 or 2, wherein the polymer (2) is a vinyl alcohol polymer.

7. The laminate according to claim 6, wherein the vinyl alcohol polymer of polymer (2) has a viscosity average degree of polymerization of 200 to 5,000 and a degree of saponification of 70 to 100 mol %.

8. The laminate according to claim 1 or 2, which has a heat seal layer (D) on the outermost surface.

9. The laminate according to claim 8, wherein the heat seal layer (D) contains at least one polymer (3) selected from the group consisting of olefin polymers, styrene polymers, and polyester polymers.

10. The laminate of claim 9, wherein the polymer (3) contains a styrene-acrylic copolymer.

11. The laminate according to claim 9, wherein the heat seal layer (D) contains 1 part by mass or more and 50 parts by mass or less of a vinyl alcohol polymer per 100 parts by mass of the polymer (3).

12. The laminate according to claim 8, wherein the heat seal layer (D) is positioned on the outermost surface of the paper substrate on the side of the vapor deposition layer (C).