Laminate

Abstract

Provided is a laminate having high interlayer adhesion. The laminate contains a substrate, a resin layer (1), and a resin layer (2), the resin layer (1) and the resin layer (2) being adjacent to each other, the resin layer (1) containing a polymer (1), the resin layer (2) containing a vinyl alcohol-based polymer (a) and a polymer (2), the polymer (1) being at least one polymer selected from the group consisting of cationic polymers, vinyl alcohol-based polymers (b) and urethane-based polymers, and the polymer (2) being at least one polymer selected from the group consisting of polyalkyleneimines and urethane-based polymers.

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 sealant 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] Conventional laminates having a structure in which a gas barrier layer and another layer are directly laminated have the disadvantage that the adhesion between these layers is insufficient. When the adhesion between the layers of a laminate is insufficient, peeling between the layers occurs during use, processing, etc., which can lead to a decrease in barrier properties, etc.

[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 high interlayer adhesion.

[0006] The above-mentioned problems are solved by the following: [1] a laminate having a substrate, a resin layer (1) and a resin layer (2), the resin layer (1) and the resin layer (2) being adjacent to each other, the resin layer (1) containing a polymer (1), the resin layer (2) containing a vinyl alcohol-based polymer (a) and a polymer (2), the polymer (1) being at least one selected from the group consisting of a cationic polymer, a vinyl alcohol-based polymer (b) and a urethane-based polymer, and the polymer (2) being at least one selected from the group consisting of a polyalkyleneimine and a urethane-based polymer; [2] the laminate of [1], in which the content of the polymer (2) in the resin layer (2) is 3 parts by mass or more and 30 parts by mass or less per 100 parts by mass of the vinyl alcohol-based polymer (a); [3] the laminate of [1] or [2], in which the polymer (2) is the polyalkyleneimine; [4] the laminate of any of [1] to [3], in which the number-average molecular weight of the polyalkyleneimine is 30,000 or more; [5] The laminate of any one of [1] to [4], wherein the resin layer (1) further contains a water-dispersible polymer; [6] The laminate of [5], wherein the water-dispersible polymer is at least one selected from the group consisting of an olefin-based polymer and a styrene-based polymer; [7] The laminate of [5] or [6], wherein the content of the polymer (1) in the resin layer (1) is 0.1 parts by mass or more and 20 parts by mass or less per 100 parts by mass of the water-dispersible polymer; [8] The laminate of any one of [1] to [7], wherein the polymer (1) is the cationic polymer; [9] The laminate of any one of [1] to [8], wherein the cationic polymer is a polyamide-based resin;

[10] The laminate of any one of [1] to [9], wherein the resin layer (1) further contains a layered inorganic material;

[11] The laminate of

[10] , wherein the aspect ratio of the layered inorganic material is 500 or more;

[12] The laminate of

[10] or

[11] , wherein the resin layer (1) further contains a water-dispersible polymer, and the content of the layered inorganic material in the resin layer (1) is 1 part by mass or more and less than 50 parts by mass per 100 parts by mass of the water-dispersible polymer;

[13] Any of the laminates of

[10] to

[12] , wherein the content of the layered inorganic material in the resin layer (1) is 1% by mass or more and 40% by mass or less;

[14] Any of the laminates of [1] to [6] and [8] to

[13] , wherein the content of the polymer (1) in the resin layer (1) is 50% by mass or more;

[15] The problem is solved by providing any one of the laminates of [1] to

[14] , which has, as an outermost layer, a sealant layer containing at least one polymer (3) selected from the group consisting of an olefin polymer and a styrene polymer;

[16] The problem is solved by providing any one of the laminates of [1] to

[15] , wherein the substrate is paper.

[0007] According to the present invention, a laminate having high interlayer adhesion can be provided.

[0008] <Laminate> A laminate according to one embodiment of the present invention has a substrate, a resin layer (1) and a resin layer (2), the resin layer (1) and the resin layer (2) being adjacent to each other, the resin layer (1) containing a polymer (1), the resin layer (2) containing a vinyl alcohol-based polymer (a) and a polymer (2), the polymer (1) being at least one selected from the group consisting of a cationic polymer, a vinyl alcohol-based polymer (b) and a urethane-based polymer, and the polymer (2) being at least one selected from the group consisting of a polyalkyleneimine and a urethane-based polymer.

[0009] A laminate according to one embodiment of the present invention has high interlayer adhesion. While the reason for this is unclear, the following is thought to be the case. Because the polymer (2) contained in the resin layer (2) has a polar group, it has a high affinity with the vinyl alcohol polymer (a) in the resin layer (2) and also interacts with the polymer (1) having a polar group contained in the resin layer (1). Thus, in this laminate, the interlayer adhesion is thought to be enhanced due to the interaction between the polymers of the resin layer (1) and the resin layer (2). Furthermore, because the polymer (2) contained in the resin layer (2) also has a hydrophobic group, in a preferred embodiment in which the resin layer (1) further contains a water-dispersible polymer, it is thought to interact with the water-dispersible polymer in the resin layer (1), further enhancing the interlayer adhesion. It should be noted that when the adhesion between the resin layer (1) and the resin layer (2) in the laminate is enhanced, it is considered that the problem of providing a laminate with high interlayer adhesion has been solved. Furthermore, the laminate can exhibit good oxygen barrier properties due to the presence of the resin layer (2), and in a preferred embodiment in which the resin layer (1) further contains a water-dispersible polymer, the laminate can also exhibit good water vapor barrier properties due to the presence of the resin layer (1). Each layer will be described in detail below.

[0010] (Substrate) The substrate may be the outermost layer on one side of the laminate. That is, no other layer may be laminated on one side of the substrate. Other layers may be laminated on both sides of the substrate. The substrate may be printed or the like.

[0011] In this specification, the outermost layer refers to a layer having one exposed surface. The term "outermost layer" does not distinguish between the inner surface and the outer surface of the laminate. That is, the laminate has two outermost layers. For example, when the laminate is formed into a bag shape, both the innermost layer and the outermost layer are outermost layers.

[0012] The material of the substrate is not particularly limited, and substrates made of various materials can be used. Examples of substrates that can be used include resin films such as thermoplastic resin films and thermosetting resin films, fiber aggregates such as paper and fabric, and metal foils. The resin film may be a stretched film or a non-stretched film. Among these, the substrate is preferably a fiber aggregate, and paper is more preferred. The substrate may be a single-layer or multi-layer substrate. In the case of a multi-layer substrate, each layer may be made of a different material, such as a multi-layer substrate formed by laminating a resin film on paper.

[0013] The base paper 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. The base paper is also referred to as a paper base material. In addition to pulp, the paper base material may contain sizing agents, fillers, paper strength agents, retention aids, pH adjusters, drainage aids, waterproofing agents, softeners, antistatic agents, antifoaming agents, slime control agents, dyes, pigments, etc.

[0014] 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.

[0015] 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:

[0016] 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:

[0017] The paper substrate can be produced by a conventionally known method, and commercially available paper substrates can also be used.

[0018] The average thickness of the substrate (paper substrate and other substrate) may be, for example, in the range of 1 μm to 1000 μm, in the range of 3 μm to 400 μm, in the range of 5 μm to 100 μm, or in the range of 7 μm to 50 μm.

[0019] (Resin layer (1)) The resin layer (1) contains a polymer (1). The resin layer (1) may be a layer having a resin content of 50% by mass or more and 100% by mass or less. The resin layer (1) may be a layer formed by coating (coated layer). The resin layer (1) may be a layer that mainly exhibits water vapor barrier properties, or may be a layer that mainly functions as a sealing layer.

[0020] The resin layer (1) may contain the polymer (1), and may be a layer consisting of only the polymer (1), but preferably further contains a water-dispersible polymer. When the resin layer (1) contains the polymer (1) and the water-dispersible polymer, the resin layer (1) is a layer that mainly exhibits water vapor barrier properties, and the laminate has excellent water vapor barrier properties.

[0021] (Water-Dispersible Polymer) The resin layer (1) can exhibit good water vapor barrier properties by further containing a water-dispersible polymer. The water-dispersible polymer may be, for example, a polymer having structural units derived from a hydrocarbon-based monomer, or a copolymer having structural units derived from a hydrocarbon-based monomer and other structural units. Examples of hydrocarbon-based monomers include olefins and styrene-based compounds, which will be described later. The ratio of structural units derived from hydrocarbon-based monomers to all structural units in the water-dispersible polymer may be, for example, 40 mol% to 100 mol%, 50 mol% to 99 mol%, or 60 mol% to 95 mol%. The water-dispersible polymer may be a polymer that is substantially insoluble in water but dispersible in water. The solubility of the water-dispersible polymer in water at 20°C may be, for example, 1 g / 100 g or less, 0.1 g / 100 g or less, or 0.01 g / 100 g or less. Examples of water-dispersible polymers include olefin-based polymers, styrene-based polymers, and polyester-based polymers. The water-dispersible polymer may be the main component of the resin layer 1. One or more types of water-dispersible polymers may be used.

[0022] (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.

[0023] Examples of the olefin include α-olefins such as ethylene, propylene, n-butene, and isobutylene.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] The olefin polymer is preferably a polyolefin, an olefin-vinyl ester copolymer, or an olefin-unsaturated carboxylic acid copolymer, and more preferably an olefin-unsaturated carboxylic acid copolymer. The olefin-vinyl ester copolymer refers to a copolymer of one or more olefins and one or more vinyl esters. The olefin-unsaturated carboxylic acid copolymer refers to a copolymer of one or more olefins and one or more unsaturated carboxylic acid compounds.

[0029] 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.

[0030] Examples of olefin-unsaturated carboxylic acid copolymers include ethylene-(meth)acrylic acid copolymer, ethylene-methyl(meth)acrylate copolymer, ethylene-ethyl(meth)acrylate copolymer, ethylene-butyl(meth)acrylate copolymer, and ethylene-maleic acid copolymer. The olefin-unsaturated carboxylic acid copolymer is preferably an olefin-unsaturated carboxylic acid copolymer, which is a copolymer of one or more olefins and one or more unsaturated carboxylic acids (e.g., ethylene-(meth)acrylic acid copolymer, ethylene-maleic acid copolymer, etc.). The olefin-unsaturated carboxylic acid copolymer is also preferably a copolymer of ethylene and an unsaturated carboxylic acid compound. A particularly preferred example of the olefin-unsaturated carboxylic acid copolymer is ethylene-(meth)acrylic acid copolymer. These copolymers may further be copolymerized with other monomers copolymerizable with the olefin and the unsaturated carboxylic acid compound.

[0031] (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.

[0032] Examples of the styrene copolymer include polystyrene, styrene-acrylic copolymer, and styrene-butadiene copolymer.

[0033] A 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.

[0034] 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.

[0035] 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.

[0036] The styrene-butadiene copolymer is preferably a styrene-butadiene copolymer, which may be further copolymerized with other monomers.

[0037] As the styrene polymer, a styrene-acrylic copolymer and a styrene-butadiene copolymer are preferred, and a styrene-acrylic copolymer is more preferred.

[0038] (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.

[0039] From the viewpoint of water vapor barrier properties and the like, the water-dispersible polymer is preferably at least one selected from the group consisting of olefin-based polymers and styrene-based polymers, and from the viewpoint of water vapor barrier properties, styrene-based polymers may be more preferable, and from the viewpoint of oxygen barrier properties, olefin-based polymers may be more preferable.

[0040] The lower limit of the content of the water-dispersible polymer in the resin layer (1) is preferably 50% by mass, more preferably 60% by mass, and may be 70%, 80%, or 90% by mass. By setting the content of the water-dispersible polymer in the resin layer (1) to be equal to or greater than the lower limit, it is possible to further improve the water vapor barrier property, etc. On the other hand, the upper limit of this content is preferably 99.9% by mass, more preferably 99% by mass, and may be 98%, 96%, 90%, or 80% by mass.

[0041] (Polymer (1)) The polymer (1) is at least one selected from the group consisting of a cationic polymer, a vinyl alcohol polymer (b), and a urethane polymer. The polymer (1) is preferably a cationic polymer. One or more types of polymer (1) can be used.

[0042] (Cationic Polymer) The cationic polymer is a polymer having a cationic group. The cationic polymer may be a polymer having a structural unit containing a cationic group.

[0043] Examples of the cationic polymer include polyamines, modified polyamides (e.g., cationically modified polyamides such as amine-modified polyamides), polyamide epichlorohydrin, polyalkyleneimines (e.g., polyethyleneimine), polyalkylenepolyamines, 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, and polydiallyldimethylammonium chloride.

[0044] The cationic polymer is preferably a polyamide resin. A polyamide resin refers to a polymer having an amide bond. Examples of polyamide resins that are cationic polymers include the above-mentioned modified polyamides, polyamide epichlorohydrin, polyamidoamine-epihalohydrin or formaldehyde condensation reaction products, polyamide polyurea-epihalohydrin or formaldehyde condensation reaction products, polyamidoamine polyurea-epihalohydrin or formaldehyde condensation reaction products, polyamide polyurea compounds, polyamidoamine polyurea compounds, and polyamidoamine compounds, with modified polyamides being more preferred.

[0045] The cationic polymer can be synthesized by a conventionally known method. Commercially available cationic polymers may also be used.

[0046] (Vinyl alcohol polymer (b)) The vinyl alcohol polymer (b) is a vinyl alcohol polymer having a vinyl alcohol unit (—CH ２ The vinyl alcohol polymer (b) is usually obtained by saponifying a vinyl ester polymer.

[0047] The viscosity-average degree of polymerization of the vinyl alcohol polymer (b) is preferably 200 or more and 5000 or less. The lower limit of the viscosity-average degree of polymerization may be 300, 400, 500, or 800. On the other hand, the upper limit of the viscosity-average degree of polymerization may be 3000, 2500, 2000, 1200, or 1000.

[0048] The viscosity-average degree of polymerization of the vinyl alcohol polymer (b) 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）

[0049] The lower limit of the saponification degree of the vinyl alcohol polymer (b) is preferably 70 mol%, more preferably 80 mol%, even more preferably 90 mol%, even more preferably 95 mol%, and may be 96 mol%, 97 mol%, 98 mol%, or 99 mol%. 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.

[0050] The vinyl alcohol polymer (b) 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.

[0051] 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 (b) can further improve interlayer adhesion, etc.

[0052] 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%, 3 mol%, 4 mol%, or 5 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%, 3 mol%, 4 mol%, or 5 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%.

[0053] 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 (b) is preferably 95 mol % or more, more preferably 99 mol % or more, and may be 100 mol %.

[0054] (Urethane-based polymer) A urethane-based polymer is a polymer having a urethane bond. A 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 oxygen barrier properties. The content is １ The identification can be performed using known analytical techniques such as H-NMR.

[0055] The urethane polymer can be synthesized by a known method. For example, the urethane polymer described in WO 2015 / 016069 can be used.

[0056] 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.

[0057] When the resin layer (1) further contains a water-dispersible polymer, the lower limit of the content of polymer (1) in the resin layer (1) is preferably 0.1 parts by mass, more preferably 0.5 parts by mass, even more preferably 1 part by mass, and even more preferably 3 parts by mass per 100 parts by mass of the water-dispersible polymer. By setting the content of polymer (1) to the above-mentioned lower limit or more, it is possible to further improve interlayer adhesion, etc. On the other hand, the upper limit of the content is preferably 20 parts by mass, more preferably 12 parts by mass, even more preferably 8 parts by mass, even more preferably 6 parts by mass, and even more preferably 3 parts by mass, in some cases. By setting the content of polymer (1) to the above-mentioned upper limit or less, it is possible to improve water vapor barrier properties, etc.

[0058] The resin layer (1) may be a layer that mainly functions as a sealing layer. In this case, the content of the polymer (1) in the resin layer (1) is preferably 50% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, and even more preferably 90% by mass or more or 95% by mass or more. When the content of the polymer (1) in the resin layer (1) is equal to or more than the above lower limit, it is possible to improve sealing performance, various barrier properties, etc. The resin layer (1) may be composed essentially of the polymer (1) alone.

[0059] When the resin layer (1) is a layer that mainly functions as a filling layer, the polymer (1) is preferably a vinyl alcohol polymer (b).

[0060] (Layered inorganic material) The resin layer (1) preferably contains a layered inorganic material. When the resin layer (1) contains a layered inorganic material, the water vapor barrier property can be improved. Examples of the layered inorganic material include micas, mica, talc, montmorillonite, kaolinite, vermiculite, smectite, hectorite, taeniolite, and acid clay, with mica being preferred. The layered inorganic material may be a natural product or a synthetic product. One or more types of layered inorganic materials may be used.

[0061] The average particle size of the layered inorganic material 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 layered inorganic material is within this range, the water vapor barrier property can be further improved. The average particle size is the average value of the particle sizes (longest diameter) of 20 randomly selected particles in a magnified image obtained by atomic force microscopy.

[0062] The aspect ratio of the layered inorganic material can be, for example, 20 or more, 100 or more, or 300 or more, but is preferably 500 or more. By using a layered inorganic material with an aspect ratio equal to or greater than the lower limit, the water vapor barrier property can be further improved. The aspect ratio may be, for example, 10,000 or less, or 7,000 or less, 3,000 or less, or 2,000 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, respectively.

[0063] It is more preferable that the resin layer (1) further contains a water-dispersible resin and a layered inorganic material. In this case, the content of the layered inorganic material in the resin layer (1) is preferably 1 part by mass or more, more preferably 5 parts by mass or more, even more preferably 10 parts by mass or more, and even more preferably 20 parts by mass or more, per 100 parts by mass of the water-dispersible polymer. The content is preferably less than 50 parts by mass, more preferably 40 parts by mass or less, and even more preferably 35 parts by mass or less. By setting the content of the layered inorganic material in the resin layer (1) within the above range, the water vapor barrier property can be further improved.

[0064] In one preferred embodiment, the resin layer (1) functions primarily as a filling layer and further contains a layered inorganic material. In this case, the content of the layered inorganic material in the resin layer (1) is preferably 1 part by mass or more, more preferably 5 parts by mass or more, even more preferably 10 parts by mass or more, and even more preferably 20 parts by mass or more, per 100 parts by mass of the polymer (1). The content is preferably less than 50 parts by mass, more preferably 40 parts by mass or less, and even more preferably 35 parts by mass or less. By setting the content of the layered inorganic material in the resin layer (1) within the above range, the water vapor barrier property and oxygen barrier property can be further improved. Furthermore, the total content of the polymer (1) and the layered inorganic material in the resin layer (1) is preferably 50% by mass or more, more preferably 80% by mass or more, and even more preferably 90% by mass or more or 95% by mass or more. The resin layer (1) may essentially consist of only the polymer (1) and the layered inorganic material.

[0065] The lower limit of the content of the layered inorganic material in the resin layer (1) is preferably 1% by mass, more preferably 5% by mass, even more preferably 10% by mass, and even more preferably 20% by mass. The upper limit of the content of the layered inorganic material in the resin layer (1) is preferably 40% by mass, more preferably 35% by mass, even more preferably 30% by mass, and even more preferably 25% by mass. By setting the content of the layered inorganic material in the resin layer (1) within the above range, various barrier properties can be further improved.

[0066] (Other Components, etc.) The resin layer (1) may further contain other components in addition to the water-dispersible polymer, the polymer (1), and the layered inorganic material. Examples of the other components include resins other than the water-dispersible polymer and the polymer (1), dispersants, surfactants, antifoaming agents, dyes, thickeners, etc.

[0067] The total content of the polymer (1) and the optional water-dispersible polymer and layered inorganic material in the resin layer (1) may be 90% by mass or more, 95% by mass or more, 99% by mass or more, or substantially 100% by mass.

[0068] The lower limit of the mass per unit area of ​​one resin layer (1) is 1 g / m ２ is preferred, and 2 g / m２ More preferably, 3 g / m ２ More preferably, 5 g / m ２ or 7 g / m ２ is even more preferable in some cases. When the mass per unit area of ​​one resin layer (1) is equal to or greater than the above lower limit, the water vapor barrier property, oxygen barrier property, etc. can be further improved. Furthermore, when the resin layer (1) is the outermost layer, when the mass per unit area of ​​one resin layer (1) is equal to or greater than the above lower limit, the resin layer (1) can function as a sufficiently good sealant layer. The upper limit of the mass per unit area of ​​one resin layer (1) is 100 g / m ２ is preferred, and 40 g / m ２ More preferably, 20 g / m ２ More preferably, 15 g / m ２ The upper limit of the mass per unit area of ​​one resin layer (1) is 10 g / m ２ , 7 g / m ２ or 5 g / m ２ When the mass per unit area of ​​one resin layer (1) is equal to or less than the upper limit, it is possible to reduce the thickness of the laminate.

[0069] (Resin layer (2)) The resin layer (2) contains a vinyl alcohol polymer (a) and a polymer (2). The resin layer (2) may be a layer having a resin content of 50% by mass or more and 100% by mass or less. The resin layer (2) may be a layer formed by coating (coated layer). The resin layer (2) is a layer that mainly exhibits oxygen barrier properties.

[0070] (Vinyl alcohol polymer) The resin layer (2) can exhibit good oxygen barrier properties by containing a vinyl alcohol polymer (a). The vinyl alcohol polymer (a) may be the main component of the resin layer (2). One or more types of vinyl alcohol polymer (a) can be used.

[0071] The vinyl alcohol polymer (a) contained in the resin layer (2) may be an α-olefin-vinyl alcohol copolymer or an ethylene-modified polyvinyl alcohol. By using an α-olefin-vinyl alcohol copolymer, particularly an ethylene-modified polyvinyl alcohol, as the vinyl alcohol polymer (a) contained in the resin layer (2), it is possible to further improve the oxygen barrier property, etc. The specific form of the vinyl alcohol polymer (a) contained in the resin layer (2) is the same as the specific form of the vinyl alcohol polymer (b) as the polymer (1) described above.

[0072] The viscosity-average degree of polymerization of the vinyl alcohol polymer (a) contained in the resin layer (2) is preferably 200 or more and 5000 or less. The lower limit of the viscosity-average degree of polymerization may be 300, 400, 500, or 800. On the other hand, the upper limit of the viscosity-average degree of polymerization may be 3000, 2500, 2000, 1200, or 1000. When the viscosity-average degree of polymerization of the vinyl alcohol polymer (a) contained in the resin layer (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 formed layer, etc. are also optimized.

[0073] The lower limit of the saponification degree of the vinyl alcohol polymer (a) contained in the resin layer (2) is preferably 70 mol%, more preferably 80 mol%, even more preferably 90 mol%, even more preferably 95 mol%, and may be 96 mol%, 97 mol%, 98 mol%, or 99 mol%. When the saponification degree is equal to or greater than the lower limit, 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%.

[0074] The lower limit of the content of α-olefin units relative to all monomer units in the α-olefin-vinyl alcohol copolymer contained in the resin layer (2) is preferably 0.1 mol%, more preferably 0.5 mol%, even more preferably 1 mol%, and may be 2 mol%, 3 mol%, 4 mol%, or 5 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 contained in the resin layer (2) is preferably 0.1 mol%, more preferably 0.5 mol%, even more preferably 1 mol%, and may be 2 mol%, 3 mol%, 4 mol%, or 5 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%.

[0075] The total content of vinyl alcohol units, vinyl ester units, and any α-olefin units relative to all monomer units of the vinyl alcohol polymer (a) contained in the resin layer (2) is preferably 95 mol% or more, more preferably 99 mol% or more, and may be 100 mol%.

[0076] The lower limit of the content of the vinyl alcohol polymer (a) in the resin layer (2) is 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 the vinyl alcohol polymer (a) in the resin layer (2) to the above lower limit or more, it is possible to improve the water vapor barrier property, oxygen barrier property, etc. On the other hand, the upper limit of the content of the vinyl alcohol polymer (a) in the resin layer (2) is preferably 99% by mass, and may be 98% by mass, 97% by mass, 96% by mass, or 95% by mass.

[0077] (Polymer (2)) The polymer (2) is at least one selected from the group consisting of polyalkyleneimine and urethane polymer. The polymer (2) is preferably polyalkyleneimine. One or more types of polymer (2) can be used.

[0078] The polyalkyleneimine is preferably a polyalkyleneimine having an alkylene unit having 2 to 5 carbon atoms. Examples of the polyalkyleneimine include polyethyleneimine and polypropyleneimine, with polyethyleneimine being preferred. The polyalkyleneimine may be linear or branched.

[0079] The lower limit of the number average molecular weight of the polyalkyleneimine is preferably 30,000, more preferably 50,000, even more preferably 70,000, and even more preferably 80,000. When the number average molecular weight of the polyalkyleneimine is equal to or greater than the lower limit, interlayer adhesion is further improved. The upper limit of the number average molecular weight of the polyalkyleneimine may be, for example, 300,000, 200,000, or 150,000. The number average molecular weight of the polyalkyleneimine is a value measured by dissolving the polyalkyleneimine in a solvent capable of dissolving it and using gel permeation chromatography (GPC).

[0080] 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.

[0081] The lower limit of the content of polymer (2) in the resin layer (2) may be, for example, 0.5 parts by mass or 1 part by mass relative to 100 parts by mass of the vinyl alcohol-based polymer (a), but may be preferably 3 parts by mass, and more preferably 5 parts by mass or 8 parts by mass. By setting the content of polymer (2) to the above lower limit or more, it is possible to further improve interlayer adhesion, etc. On the other hand, the upper limit of the content is preferably 30 parts by mass, more preferably 25 parts by mass, even more preferably 20 parts by mass, and even more preferably 15 parts by mass, 12 parts by mass, 8 parts by mass or 5 parts by mass. By setting the content of polymer (2) to the above upper limit or less, it is possible to improve oxygen barrier properties, etc.

[0082] (Other Components, etc.) The resin layer (2) may further contain other components in addition to the vinyl alcohol polymer (a) and the polymer (2). Examples of other components include resins other than the vinyl alcohol polymer (a) and the polymer (2), layered inorganic materials, dispersants, surfactants, antifoaming agents, dyes, preservatives, fillers, interlayer adhesives, thickeners, etc. For example, when the resin layer (2) contains a layered inorganic material, the water vapor barrier property and oxygen barrier property tend to be further improved. The layered inorganic materials that can be used in the resin layer (2) are the same as the layered inorganic materials used in the resin layer (1) described above.

[0083] The total content of the vinyl alcohol polymer (a) and the polymer (2) in the resin layer (2) is preferably 90% by mass or more, more preferably 95% by mass or more or 99% by mass or more. When the total content of the vinyl alcohol polymer (a) and the polymer (2) in the resin layer (2) is equal to or more than the lower limit, interlayer adhesion and the like tend to be further improved.

[0084] The mass per unit area of ​​one resin layer (2) 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 ２The following is even more preferable: When the mass per unit area of ​​one resin layer (2) is equal to or greater than the above lower limit, it is possible to improve the water vapor barrier property, oxygen barrier property, etc. On the other hand, when the mass per unit area of ​​one resin layer (2) is equal to or less than the above upper limit, it is possible to reduce the thickness of the laminate, etc.

[0085] (Sealant Layer) The laminate according to one embodiment of the present invention preferably further includes a sealant layer. The sealant layer is usually the outermost layer of the laminate. The outermost layer on one side of the laminate may be a sealant layer, or the outermost layers on both sides may be sealant layers. The sealant layer may be a layer formed by coating (coating layer).

[0086] The sealant layer usually contains a polymer as a main component. The polymer used in the sealant layer is preferably a thermoplastic resin. The melting point of the polymer used in the sealant layer is preferably 50°C or higher and 150°C or lower, more preferably 70°C or higher and 110°C or lower. One or more types of polymers can be used.

[0087] (Polymer (3)) The polymer used in the sealant layer is preferably at least one polymer (3) selected from the group consisting of olefin polymers and styrene polymers. Specific and preferred embodiments of these polymers (3) are the same as those of the olefin polymers and styrene polymers described above as the water-dispersible polymers. One or more types of polymer (3) can be used.

[0088] The olefin polymer as polymer (3) is preferably an olefin-vinyl ester copolymer or an olefin-unsaturated carboxylic acid copolymer, more preferably an olefin-unsaturated carboxylic acid copolymer, even more preferably an olefin-unsaturated carboxylic acid copolymer, and even more preferably an ethylene-(meth)acrylic acid copolymer. The styrene copolymer as polymer (3) is preferably a styrene-acrylic copolymer.

[0089] The lower limit of the content of polymer (3) in the sealant layer is preferably 50% by mass, more preferably 60% by mass, even more preferably 70% by mass, and even more preferably 80%, 85%, 90%, or 95% by mass. By setting the content of polymer (3) to the above lower limit or more, it is possible to improve heat sealability, etc. On the other hand, the upper limit of this content is preferably 100% by mass, and may be 99% or 95% by mass.

[0090] The sealant layer may contain a vinyl alcohol polymer. When the sealant layer contains a vinyl alcohol polymer, the smoothness of the sealant layer surface can be improved. Furthermore, when the sealant layer contains a vinyl alcohol polymer, the water vapor barrier property and oxygen barrier property of the laminate can be further improved. The specific form of the vinyl alcohol polymer contained in the sealant layer is the same as the specific form of the vinyl alcohol polymer (b) as the polymer (1) described above. One or more types of vinyl alcohol polymers can be used in the sealant layer.

[0091] The sealant layer may further contain components other than the above-mentioned polymer, such as wax, dispersant, surfactant, antifoaming agent, dye, thickener, etc.

[0092] The mass per unit area of ​​one sealant layer 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 ２The following is particularly preferred. When the mass per unit area of ​​one sealant layer is equal to or greater than the above lower limit, sufficient heat sealing properties can be exhibited and water vapor barrier properties, oxygen barrier properties, etc. can be further improved. On the other hand, when the mass per unit area of ​​one sealant layer is equal to or less than the above upper limit, the laminate can be made thinner, etc.

[0093] (Other Layers) The laminate according to one embodiment of the present invention may further include layers other than the substrate, resin layer (1), resin layer (2), and sealant layer. Examples of other layers include other resin layers, vapor deposition layers, metal foil layers, etc. In one embodiment of the present invention, the laminate may not include layers other than the substrate, resin layer (1), resin layer (2), and any sealant layer. For example, the laminate may not include a vapor deposition layer.

[0094] When the laminate according to one embodiment of the present invention has a vapor-deposited layer, it can exhibit excellent water vapor barrier properties, oxygen barrier properties, etc. The vapor-deposited layer is a layer formed by vapor deposition, and is preferably a layer formed by vapor deposition of an inorganic substance (inorganic vapor-deposited layer).

[0095] Examples of materials constituting the vapor-deposited layer 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 examples of inorganic materials listed above, silicon is considered to be included in the metals. The vapor-deposited layer 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 is preferably aluminum, aluminum oxide, silicon oxide, magnesium oxide, or silicon nitride, more preferably aluminum or aluminum oxide, and even more preferably aluminum.

[0096] The lower limit of the average thickness of one vapor-deposited layer 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 to the above 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 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 to the above upper limit or less, cracking of the vapor-deposited layer during bending, etc., can be suppressed, and deterioration of the water vapor barrier properties and oxygen barrier properties after bending can be reduced. The average thickness of the vapor-deposited layer is the average value of the thicknesses at any 10 points on the cross section of the vapor-deposited layer measured using an electron microscope.

[0097] (Layer structure, etc.) In a laminate according to one embodiment of the present invention, the resin layer (1) and the resin layer (2) are adjacent to each other. The resin layer (1) and the resin layer (2) may be in direct contact with each other. In the laminate, the interlayer adhesion between the resin layer (1) and the resin layer (2) is high.

[0098] At least one of the resin layer (1) and the resin layer (2) is preferably in contact with the substrate, and more preferably the resin layer (1) is in contact with the substrate. That is, in the laminate, the substrate, the resin layer (1), and the resin layer (2) are preferably directly laminated in this order, or the substrate, the resin layer (2), and the resin layer (1) are preferably directly laminated in this order, and more preferably the substrate, the resin layer (1), and the resin layer (2) are directly laminated in this order.

[0099] Furthermore, when the laminate further has a sealant layer, it is preferable that the sealant layer is laminated on the resin layer (2), and it is more preferable that the substrate, the resin layer (1), the resin layer (2), and the sealant layer are laminated in this order. Note that when the resin layer (1) is located as the outermost layer in the laminate, this resin layer (1) can function as a sealant layer.

[0100] In a laminate according to one embodiment of the present invention, the substrate, resin layer (1), resin layer (2), and optional sealant layer may each be only one layer or two or more layers. In a laminate according to one embodiment of the present invention, the substrate, resin layer (1), resin layer (2), and sealant layer each preferably have only one layer. When there are two or more layers of any of the substrate, resin layer (1), resin layer (2), and sealant layer, their compositions, thicknesses, etc. may be the same or different. Furthermore, when there are two or more layers of any of the resin layer (1) and resin layer (2), there may be a resin layer (1) or resin layer (2) that is not adjacent to the other of the resin layer (1) and resin layer (2). That is, it is sufficient that at least one pair of resin layer (1) and resin layer (2) exists adjacent to each other.

[0101] Examples of the layer structure of the laminate according to one embodiment of the present invention are as follows: 1 represents resin layer (1), 2 represents resin layer (2), S represents sealant layer, and X represents other layers. Substrate / 1 / 2 Substrate / 2 / 1 Substrate / 1 / 2 / 1 Substrate / 2 / 1 / 2 Substrate / X / 1 / 2 Substrate / X / 2 / 1 Substrate / 1 / 2 / S Substrate / 1 / 2 / X Substrate / 1 / 2 / X / S Substrate / 2 / 1 / X Substrate / 2 / 1 / X / S 2 / 1 / substrate / 1 / 2 1 / 2 / substrate / 2 / 1 S / 2 / 1 / substrate / 1 / 2 / S S / substrate / 1 / 2 / S

[0102] 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 sealant layer, 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 sealant layers together. The heat-sealing method is not particularly limited, and known methods can be used, such as a hot plate heat sealer, impulse sealer, ultrasonic sealer, frictional heat sealer, dielectric heating sealer, etc.

[0103] <Method for manufacturing laminate> The method for manufacturing a laminate according to one embodiment of the present invention is not particularly limited, but it can typically be manufactured by providing a resin layer (1) and a resin layer (2) on a substrate by coating. The order of coating for providing the resin layer (1) and the resin layer (2) is not particularly limited, but it is preferable to provide the resin layer (1) and the resin layer (2) on the substrate in this order by coating. In the case of a laminate having a sealant layer, the sealant layer can also be provided by coating. The sealant layer may be provided by a method other than coating.

[0104] For example, the resin layer (1), the resin layer (2), and the sealant layer 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.

[0105] 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.

[0106] 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.

[0107] <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.

[0108] 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.

[0109] 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.

[0110] <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.

[0111] 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.

[0112] The oxygen permeability of the gas barrier paper is 100 cc / atm / m ２ / day or less is preferable, and 30cc / atm / m ２ / day or less is more preferable, and 10cc / atm / m ２ / day or less is more preferable, and 3 cc / atm / m ２ The oxygen permeability is a value measured under conditions of 20°C and 65% RH.

[0113] <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.

[0114] 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.

[0115] 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.

[0116] (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.

[0117] (Evaluation of Oxygen Barrier Property) The oxygen transmission rate (OTR) of the laminate was measured under conditions of 20° C. and 65% RH using an oxygen transmission rate measuring device (OX-TRAN2 / 20, manufactured by MOCON Corporation).

[0118] (Evaluation of Interlayer Adhesion) To evaluate interlayer adhesion, peel strength was measured by the following method. One test piece was cut out from the laminate and designated as test piece 1. Next, a dispersion of ethylene-acrylic acid copolymer ("Zaixen AC" manufactured by Sumitomo Seika Chemicals Co., Ltd.) was applied to the same substrate as used in the examples in a coating amount of 6 g / m. ２The coating was performed so that the thickness of the sealant layer was 180°C. After coating, the sealant layer was dried to form a sealant layer, which was then cut into a piece having the same area as that of test piece 1 to obtain test piece 2. Test piece 1 and test piece 2 were overlapped so that the outermost surfaces opposite the substrate were in contact with each other, and a region corresponding to approximately half the area of ​​the test piece was thermocompression-bonded. The thermocompression bonding conditions were a temperature of 150°C, a compression time of 1 second, and a pressure of 2 kgf. A tensile test was performed on the resulting partially fused test piece using a tensile tester at a peel angle of 180° and a peel rate of 300 mm / min. The state of the peeled piece after the tensile test was observed, and the peel strength was measured according to the following criteria. (Criteria) A: The area of ​​the part that peeled between the resin layer (1) and the resin layer (2) was 20% or less. B: The area of ​​the part that peeled between the resin layer (1) and the resin layer (2) was more than 20% but not more than 80%. C: The area of ​​the peeled portion between the resin layer (1) and the resin layer (2) is more than 80%. It is possible to visually determine whether the peeled piece after the tensile test is the substrate alone or has some kind of coating layer on the substrate. Furthermore, the resin layer (2) has the property of reacting with iodine and turning blue. Therefore, by visual observation and utilizing this property, it is possible to identify which layers have peeled. Furthermore, the adhesion strength between the substrate and sealant layer of test piece 2, and between the sealant layer of test piece 2 and the sealant layer of test piece 1, is considered to be sufficiently high. Therefore, for example, in the tensile tests of Examples 1 to 16 and Comparative Examples 1 to 3, in which the test pieces after thermocompression bonding have a layer structure of test piece 1 (substrate / resin layer (1) / resin layer (2) / sealant layer) / test piece 2 (sealant layer / substrate), peeling occurs between the substrate and resin layer (1), between the resin layer (1) and the resin layer (2), or between the resin layer (2) and the sealant layer. After the tensile test, the peeled piece on the test piece 1 side was visually observed, and the portion of the peeled piece consisting only of the substrate was found to have peeled between the substrate and the resin layer (1). The peeled piece on the test piece 1 side was immersed in an iodine aqueous solution, and the portion that did not turn blue was found to have peeled between the resin layer (1) and the resin layer (2), and the portion that turned blue was found to have peeled between the resin layer (2) and the sealant layer. That is, the area of ​​the peeled portion between the resin layer (1) and the resin layer (2) can be calculated by determining the area of ​​the portion of the peeled piece on the test piece 1 side that has some coating layer on the substrate and does not turn blue when immersed in an iodine aqueous solution.

[0119] The materials used in the production of the laminates of the Examples and Comparative Examples are as follows: (Water-dispersible polymer and polymer (3)) EAA: ethylene-acrylic acid copolymer ("Zaixen AC" manufactured by Sumitomo Seika Chemicals Co., Ltd.) SA: styrene-acrylic copolymer ("Joncryl 4110" manufactured by BASF)

[0120] (Polymer (1)) Cationic polymer: modified polyamide resin ("SPI201" manufactured by Taoka Chemical Co., Ltd.) PVOH-1: ethylene-modified polyvinyl alcohol having a viscosity average degree of polymerization of 900, a degree of saponification of 99.2 mol%, and an ethylene modification amount of 6.5 mol% Polyurethane: "NeorezR600" (manufactured by Covestro Coating Resins)

[0121] (Layered inorganic materials) Mica-1: "NTS-10NC" manufactured by Topy Industries, Ltd. (aspect ratio 1000) Mica-2: "ME-100B4T" manufactured by Katakura Corp. (aspect ratio 100)

[0122] (Vinyl alcohol polymers) PVOH-1: ethylene-modified polyvinyl alcohol having a viscosity average degree of polymerization of 900, a degree of saponification of 99.2 mol%, and an ethylene modification amount of 6.5 mol% PVOH-2: ethylene-modified polyvinyl alcohol having a viscosity average degree of polymerization of 2,100, a degree of saponification of 98.0 mol%, and an ethylene modification amount of 4.0 mol% PVOH-3: ethylene-modified polyvinyl alcohol having a viscosity average degree of polymerization of 550, a degree of saponification of 96.0 mol%, and an ethylene modification amount of 6.8 mol% PVOH-4: polyvinyl alcohol having a viscosity average degree of polymerization of 400, and a degree of saponification of 98.0 mol% PVOH-5: vinyl alcohol polymer ("BVE8049Q", manufactured by Mitsubishi Chemical Corporation)

[0123] (Polymer (2)) PEI-1: polyethyleneimine having a number average molecular weight of 100,000 ("Epomin P-3000" manufactured by Nippon Shokubai Co., Ltd.) PEI-2: polyethyleneimine having a number average molecular weight of 70,000 ("Epomin P-1000" manufactured by Nippon Shokubai Co., Ltd.) Polyurethane: urethane polymer "NeorezR600" (manufactured by Covestro Coating Resins)

[0124] Example 1 A coating liquid (1) for forming a resin layer (1) was prepared by mixing a modified polyamide resin (SPI201, Taoka Chemical Co., Ltd.) as a polymer (1) with a dispersion of ethylene-acrylic acid copolymer (EAA), a water-dispersible polymer (Zaixen AC, manufactured by Sumitomo Seika Chemicals Co., Ltd.). The content of polymer (1) in coating liquid (1) was 1 part by mass per 100 parts by mass of the water-dispersible polymer. Furthermore, no layered inorganic material was contained in coating liquid (1). A coating liquid (2) for forming a resin layer (2) was prepared by mixing PEI-1, a polymer (2), with an aqueous solution of PVOH-1, a vinyl alcohol-based polymer (a). The content of polymer (2) in coating liquid (2) was 5 parts by mass per 100 parts by mass of the vinyl alcohol-based polymer. A dispersion of ethylene-acrylic acid copolymer (EAA), which is polymer (3) (Zaixen AC, manufactured by Sumitomo Seika Chemicals Co., Ltd.) was prepared as coating liquid (3) for forming a sealant layer.

[0125] Basis weight as base material: 80 g / m ２ The coating weight after drying was 10 g / m on bleached kraft paper. ２ The coating solution (1) was applied using a reverse gravure coater so that the coating amount after drying was 3 g / m. ２ The coating solution (2) was applied using a reverse gravure coater so that the coating amount after drying was 6 g / m. ２ The coating liquid (3) was applied using a wire bar so that the thickness of the resin layer (1) was 100° C. and the applied coating liquid (3) was dried for 5 minutes at 100° C. to provide a sealant layer. In this way, a laminate (substrate / resin layer (1) / resin layer (2) / sealant layer) of Example 1 was obtained.

[0126] The water vapor barrier property (WVTR) of the obtained laminate of Example 1 was 167 cc / m ２ / day, oxygen barrier (OTR) is 2.1cc / atm / m ２ The interlayer adhesion (peel strength) was evaluated as A.

[0127] [Examples 2 to 17, Comparative Examples 1 to 3] The coating liquids (1) to (3) were appropriately changed so that the type of water-dispersible polymer in the resin layer (1), the type and content of the polymer (1) (content relative to 100 parts by mass of the water-dispersible polymer), the type and content of the layered inorganic material (content relative to 100 parts by mass of the water-dispersible polymer), the type of vinyl alcohol-based polymer (a) in the resin layer (2), the type and content of the polymer (2) (content relative to 100 parts by mass of the vinyl alcohol-based polymer (a)), and the type of polymer (3) in the sealant layer were as shown in Table 1. Note that "-" in Table 1 indicates that the component was not contained. Furthermore, the coating amount of each layer was changed as shown in Table 1. Each laminate (substrate / resin layer (1) / resin layer (2) / sealant layer) of Examples 2 to 17 and Comparative Examples 1 to 3 was obtained in the same manner as in Example 1 except for the above points. Each of the resulting laminates was evaluated for water vapor barrier property (WVTR), oxygen barrier property (OTR), and interlayer adhesion (peel strength). The evaluation results are shown in Table 1.

[0128] [Example 18] The coating liquids (1) and (2) were changed so that the type of water-dispersible polymer in the resin layer (1), the type and content of the polymer (1) (content relative to 100 parts by mass of the water-dispersible polymer), the type and content of the layered inorganic material (content relative to 100 parts by mass of the water-dispersible polymer), and the type of vinyl alcohol-based polymer (a) in the resin layer (2), the type and content of the polymer (2) (content relative to 100 parts by mass of the vinyl alcohol-based polymer (a)) were as shown in Table 1. In addition, the substrate was coated with the coating liquid (2) and the coating liquid (1) in that order, without coating with the coating liquid (3), and the coating amount of each layer was changed as shown in Table 1. A laminate of Example 18 (substrate / resin layer (2) / resin layer (1)) was obtained in the same manner as in Example 1, except for the above points. The obtained laminate was evaluated for water vapor barrier property (WVTR), oxygen barrier property (OTR), and interlayer adhesion (peel strength). The evaluation results are shown in Table 1.

[0129] Example 19 An aqueous solution of PVOH-1, which is the polymer (1), was prepared and used as coating liquid (1) for forming the resin layer (1). The coating liquid (1) did not contain a layered inorganic material. A coating liquid (2) for forming the resin layer (2) was prepared by mixing PEI-1, which is the polymer (2), with an aqueous solution of PVOH-1, which is the vinyl alcohol-based polymer (a). The content of polymer (2) in coating liquid (2) was 5 parts by mass per 100 parts by mass of the vinyl alcohol-based polymer (a). A dispersion of ethylene-acrylic acid copolymer (EAA), which is the polymer (3) ("Zaixen AC" manufactured by Sumitomo Seika Chemicals Co., Ltd.), was prepared as coating liquid (3) for forming the sealant layer.

[0130] Basis weight as base material: 80 g / m ２ The coating weight after drying was 3 g / m on bleached kraft paper. ２ The coating solution (1) was applied using a reverse gravure coater so that the coating amount after drying was 3 g / m. ２ The coating solution (2) was applied using a reverse gravure coater so that the coating amount after drying was 6 g / m. ２ The coating liquid (3) was applied using a wire bar so that the thickness of the coating liquid (3) was 100°C for 5 minutes, and the coating liquid (3) was dried at 100°C for 5 minutes to provide a sealant layer. As a result, a laminate (substrate / resin layer (1) / resin layer (2) / sealant layer) of Example 19 was obtained. In this case, the resin layer (1) mainly functions as a sealing layer. The evaluation results are shown in Table 1.

[0131] [Example 20] A laminate of Example 20 (substrate / resin layer (1) / resin layer (2) / sealant layer) was obtained in the same manner as in Example 19, except that mica was added as the layered inorganic material to the coating liquid (1). The content of the layered inorganic material in the coating liquid (1) was 30 parts by mass per 100 parts by mass of the polymer (1). In this case, the resin layer (1) was a layer that mainly functioned as a sealing layer. The evaluation results are shown in Table 1.

[0132]

[0133] The laminates of Examples 1 to 20 each had high interlayer adhesion. Furthermore, the laminates of Examples 1 to 20 each had high oxygen barrier properties, and the laminates of Examples 1 to 18 in particular also had high water vapor barrier properties and oxygen barrier properties.

[0134] 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 comprising a substrate, a resin layer (1) and a resin layer (2), wherein the resin layer (1) and the resin layer (2) are adjacent to each other, the resin layer (1) contains a polymer (1), the resin layer (2) contains a vinyl alcohol-based polymer (a) and a polymer (2), the polymer (1) being at least one selected from the group consisting of a cationic polymer, a vinyl alcohol-based polymer (b) and a urethane-based polymer, and the polymer (2) being at least one selected from the group consisting of a polyalkyleneimine and a urethane-based polymer.

2. The laminate according to claim 1, wherein the content of the polymer (2) in the resin layer (2) is 3 parts by mass or more and 30 parts by mass or less per 100 parts by mass of the vinyl alcohol-based polymer (a).

3. The laminate according to claim 1 or 2, wherein the polymer (2) is the polyalkyleneimine.

4. The laminate according to claim 3, wherein the polyalkyleneimine has a number average molecular weight of 30,000 or more.

5. The laminate according to claim 1 or 2, wherein the resin layer (1) further contains a water-dispersible polymer.

6. The laminate according to claim 5, wherein the water-dispersible polymer is at least one selected from the group consisting of olefin-based polymers and styrene-based polymers.

7. The laminate according to claim 5, wherein the content of the polymer (1) in the resin layer (1) is 0.1 parts by mass or more and 20 parts by mass or less per 100 parts by mass of the water-dispersible polymer.

8. The laminate according to claim 1 or 2, wherein the polymer (1) is the cationic polymer.

9. The laminate according to claim 8, wherein the cationic polymer is a polyamide resin.

10. The laminate according to claim 1 or 2, wherein the resin layer (1) further contains a layered inorganic material.

11. The laminate according to claim 10, wherein the layered inorganic material has an aspect ratio of 500 or more.

12. The laminate according to claim 10, wherein the resin layer (1) further contains a water-dispersible polymer, and the content of the layered inorganic material in the resin layer (1) is 1 part by mass or more and less than 50 parts by mass per 100 parts by mass of the water-dispersible polymer.

13. The laminate according to claim 10, wherein the content of the layered inorganic material in the resin layer (1) is 1% by mass or more and 40% by mass or less.

14. A laminate according to claim 1 or claim 2, wherein the content of the polymer (1) in the resin layer (1) is 50% by mass or more.

15. A laminate according to claim 1 or 2, which has as its outermost layer a sealant layer containing at least one polymer (3) selected from the group consisting of olefin polymers and styrene polymers.

16. The laminate according to claim 1 or 2, wherein the substrate is paper.

Images