Laminate, packaging material, and recycling method

Abstract

Provided are: a laminate capable of being detached under a mild condition and being produced by a general-purpose method, and exhibiting excellent adhesive strength; a recycling method for the laminate; and a recycled plastic obtained from the laminate.　This laminate includes: a first base material; a second base material; an adhesive layer disposed between the first base material and the second base material; and a first resin layer disposed between the first base material and the adhesive layer. The first resin layer contains a first vinyl alcohol-based polymer and a first polyalkyleneimine. The first vinyl alcohol-based polymer can be dissolved in a 1:1 (mass ratio) solution of water and ethanol in an amount of 5 mass% or more at 25°C, and the solution obtained by dissolving the vinyl alcohol-based polymer in the 1:1 (mass ratio) solution of water and ethanol in an amount of 5 mass% has a viscosity of 200 mPa･s or less at 25°C. The glass transition temperature of the first resin layer is 40-80°C.

Description

Laminate, packaging material, and recycling method

[0001] The present invention relates to a laminate with excellent recyclability, a packaging material using the laminate, and a method for recycling the laminate and the packaging material.

[0002] Due to the mandatory recycling of plastic containers and packaging, plastic waste, including food packaging, has been collected, separated, and reused. There are many different types of plastic waste, including those made from synthetic resins such as polyethylene, polypropylene, polystyrene (styrofoam), polyethylene terephthalate, and polyvinyl chloride, as well as laminated films made by laminating these synthetic resin films with metal foils such as aluminum foil and applying product names or other decorative features with printing inks. These types of waste are often mixed together when collected as garbage.

[0003] Generally, waste plastics containing a mixture of thermoplastic and thermosetting resins can be recycled by separating them based on their specific gravity, but the ease of recovery varies depending on the resin. Furthermore, many packaging materials, including those used for food packaging, are made by bonding different synthetic resins together with adhesives, making separation difficult using this method. It is generally believed that recycling thermosetting resins is difficult due to their low thermal decomposition rate. Laminated films decorated with product names and other markings printed in ink cannot be completely separated during the recycling process, and recycled products may be discolored or retain the printed pattern.

[0004] As a method for treating such composite waste and separating and recovering each component, Patent Document 1 discloses a method for separating and recovering composite plastic waste, which comprises the steps of using triethylene glycol as a separating solvent, adding an alkali metal hydroxide as a catalyst, heating the triethylene glycol to 250 to 280°C, which is close to the boiling point of 200°C or more, and melting a component P1 that is soluble in triethylene glycol, dissolving or depolymerizing a component P2 that is difficult to melt under stirring in triethylene glycol heated to 250 to 280°C and discharging it together with the solvent, recovering the remaining soluble component P1 and reinforcing fiber F or metal component M, recovering the non-melted component P2 and the separating solvent, distilling the separating solvent under reduced pressure to separate it from the non-melted component P2, purifying it, and reusing it.

[0005] Japanese Patent Application Laid-Open No. 2006-110531

[0006] In order to peel the laminated film under milder conditions, it has been considered to provide a removable primer layer between the film and the adhesive layer (or printing layer). However, providing such a primer layer may reduce the adhesive strength between the films. Alternatively, depending on the type of resin used to form the primer layer, it may be difficult to efficiently form the primer layer using a conventional manufacturing method.

[0007] The present invention has been made in view of the above circumstances, and aims to provide a laminate that can be peeled off under mild conditions, has excellent adhesive strength, and can be produced by a general-purpose method, a method for recycling the laminate, and recycled plastics obtained from the laminate.

[0008] The present invention relates to a laminate comprising a first substrate, a second substrate, an adhesive layer disposed between the first substrate and the second substrate, and a first resin layer disposed between the first substrate and the adhesive layer, wherein the first resin layer comprises a first vinyl alcohol-based polymer and a first polyalkyleneimine, the first vinyl alcohol-based polymer being soluble in a 1:1 (mass ratio) solution of water and ethanol at 25°C at a concentration of 5% by mass or more, and wherein a solution in which the vinyl alcohol-based polymer is dissolved in a 1:1 (mass ratio) solution of water and ethanol at 5% by mass has a viscosity at 25°C of 200 mPa s or less, and the first resin layer has a glass transition temperature of 40°C or higher and 80°C or lower.

[0009] According to the present invention, it is possible to provide a laminate that can be peeled off under mild conditions, has excellent adhesive strength, and can be produced by a general-purpose method, a method for recycling the laminate, and recycled plastics obtained from the laminate.

[0010] <Laminate> The laminate of the present invention includes a first substrate, a second substrate, an adhesive layer disposed between the first substrate and the second substrate, and a first resin layer disposed between the first substrate and the adhesive layer. The laminate of the present invention will be described in detail below.

[0011] (First substrate) The first substrate can be any film or sheet (unless otherwise specified below, film is a general term for film and sheet) that has excellent chemical and physical strength. Examples of the first substrate include polyethylene terephthalate (PET) film, polystyrene film, polyamide film, polyacrylonitrile film, polyethylene film (LLDPE: low-density polyethylene film, HDPE: high-density polyethylene film, MDOPE: uniaxially oriented polyethylene film, OPE: biaxially oriented polyethylene film), polypropylene film (CPP: unstretched polypropylene film, OPP: biaxially oriented polypropylene film), ethylene-vinyl alcohol copolymer, polyolefin film such as a gas barrier film having an olefin-based heat-sealable resin layer on one or both sides of a resin having gas barrier properties such as polyvinyl alcohol, polyvinyl alcohol film, ethylene-vinyl alcohol copolymer film, etc.

[0012] It is also preferable to use a film made of a material containing biomass-derived components. Biomass films are commercially available from various companies, and for example, sheets such as those listed in the list of biomass-certified products listed by the Japan Organics Recycling Association can be used.

[0013] Specifically, well-known films are made from biomass-derived ethylene glycol. Biomass-derived ethylene glycol is made from ethanol (biomass ethanol) produced from biomass as a raw material. For example, biomass-derived ethylene glycol can be obtained by converting biomass ethanol into ethylene oxide by a conventionally known method to produce ethylene glycol. Alternatively, commercially available biomass ethylene glycol may be used; for example, biomass ethylene glycol commercially available from India Glycoal Limited can be suitably used.

[0014] Alternatively, products using biomass raw materials classified by the biomass plastic content specified in ISO 16620 or ASTM D6866 are also on the market. Radioactive carbon-14C exists in the atmosphere at a rate of 1 in 1012 particles, and this rate is the same for atmospheric carbon dioxide, so this rate remains the same even in plants that fix this carbon dioxide through photosynthesis. Therefore, the carbon in plant-derived resins contains radioactive carbon-14C. In contrast, the carbon in fossil fuel-derived resins contains almost no radioactive carbon-14C. Therefore, by measuring the concentration of radioactive carbon-14C in the resin using an accelerator mass spectrometer, the plant-derived resin content in the resin, i.e., the biomass plastic content, can be determined. Examples of plant-derived low-density polyethylene, which is a biomass plastic having a biomass plastic content of 80% or more, preferably 90% or more as specified by ISO 16620 or ASTM D6866, include products manufactured by Braskem under the trade names "SBC818," "SPB608," "SBF0323HC," "STN7006," "SEB853," and "SPB681," and films using these as raw materials can be suitably used.

[0015] The film may be one that has been subjected to a stretching treatment. A typical stretching method involves melt-extruding a resin into a sheet using an extrusion film-forming method or the like, followed by simultaneous biaxial stretching or sequential biaxial stretching. In the case of sequential biaxial stretching, it is common to first perform longitudinal stretching and then transverse stretching. Specifically, a method that combines longitudinal stretching utilizing the speed difference between rolls and transverse stretching using a tenter is often used.

[0016] The film surface may be subjected to various surface treatments such as flame treatment and corona discharge treatment as necessary so that an adhesive layer without defects such as film breakage or repellency is formed.

[0017] Alternatively, inorganic vapor-deposited films such as metal vapor-deposited films on which a metal layer such as aluminum is vapor-deposited, transparent vapor-deposited films on which a vapor-deposited layer of a metal oxide such as silica or alumina is laminated, or barrier films containing a gas barrier layer such as polyvinyl alcohol, an ethylene-vinyl alcohol copolymer, vinylidene chloride, etc. Such films are preferred because, when a basic compound is contained in a stripping solution for separating the laminate in the recycling step described below, the vapor-deposited layer is easily dissolved in the stripping solution, making it easier to strip the printed layer and adhesive from the resin film.

[0018] The thickness of the first substrate is not particularly limited, and may be appropriately selected in the range of 1 to 300 μm, preferably 1 to 100 μm, from the viewpoints of formability and transparency.

[0019] (Second substrate) The second substrate can be the same as the first substrate. In one embodiment of the present invention, the second substrate is a film (sealant film) having heat-sealability that can be melted by heat and fused to each other, and the first substrate is a substrate that is not expected to function as a sealant film. In another embodiment of the present invention, the second substrate is a film in which a film without heat-sealability and a resin layer (heat-seal layer) having heat-sealability are laminated, and the first substrate is a substrate that is not expected to function as a sealant film.

[0020] Examples of heat-sealable resins include polyethylene, low-density polyethylene, medium-density polyethylene, high-density polyethylene, linear low-density polyethylene, polypropylene, ethylene-vinyl acetate copolymer, ionomer resin, ethylene-(meth)acrylic acid copolymer, ethylene-ethyl(meth)acrylate copolymer, ethylene-propylene copolymer, methylpentene polymer, modified olefin resins such as polyethylene or polypropylene modified with acrylic acid, methacrylic acid, maleic anhydride, fumaric acid, or other unsaturated carboxylic acids, ethylene-(meth)acrylic acid ester-unsaturated carboxylic acid terpolymers, cyclic polyolefins, cyclic olefin copolymers, polyethylene terephthalate (PET), polyacrylonitrile (PAN), ethylene-vinyl alcohol copolymers, polyvinyl alcohol, and other gas-barrier resins, and gas-sealable heat-sealable films having an olefin-based heat-sealable resin layer on one or both sides thereof. Films, sheets, and other coating films made of one or more of these resins can be used as sealant films.

[0021] As the sealant film, any of unstretched, uniaxially stretched and biaxially stretched films can be used.

[0022] A biaxially stretched film can be obtained by, for example, longitudinally stretching the film to 2 to 4 times its original size using a roll stretching machine at 50 to 100° C., then transversely stretching the film to 3 to 5 times its original size using a tenter stretching machine in an atmosphere at 90 to 150° C., and subsequently heat-treating the film using the tenter stretching machine in an atmosphere at 100 to 240° C. Alternatively, a film that has been subjected to simultaneous biaxial stretching or sequential biaxial stretching may also be used.

[0023] An easily peelable sealant film (easy peel film) may be used as the sealant film. Any of the interfacial peeling type, cohesive peeling type, and interlayer peeling type sealant films can be used, and can be appropriately selected depending on the type and required properties of the packaging material described below. The index of easy peelability is appropriately set depending on the type and required properties of the packaging material, and an example is a seal strength of 2 to 20 N / 15 mm. For example, easy peelability can be achieved by a phase-separated polymer blend that combines polypropylene with high-density polyethylene, low-density polyethylene, ethylene-vinyl acetate copolymer, or the like.

[0024] When the second substrate is a film in which a film without heat sealing properties and a resin layer (heat sealing layer) with heat sealing properties are laminated, the second substrate can be, for example, a film without heat sealing properties coated with a heat sealing agent containing a resin with heat sealing properties.

[0025] Examples of heat-sealable resins include thermoplastic resins such as shellacs, rosins, rosin-modified maleic acid resins, rosin-modified phenolic resins, nitrocellulose, cellulose acetate, cellulose acetyl propionate, cellulose acetyl butyrate, chlorinated rubber, cyclized rubber, vinyl chloride, vinylidene chloride, polyamide resins, vinyl chloride-vinyl acetate copolymers, polyester resins, ketone resins, butyral resins, chlorinated polypropylene resins, chlorinated polyethylene resins, chlorinated ethylene vinyl acetate resins, ethylene vinyl acetate resins, acrylic resins, urethane resins, ethylene-vinyl alcohol resins, styrene-maleic acid resins, casein, and alkyd resins, and these may be used alone or in combination of two or more.

[0026] The heat sealing agent may be in any form, such as a type in which these resins are dissolved in an organic solvent, a type in which these resins are dissolved in water or an aqueous organic solvent, or an emulsion type in which an acrylic emulsion, a urethane emulsion, a polyvinyl alcohol resin, an ethylene-vinyl alcohol emulsion, an ethylene-methacrylic acid emulsion, a polyolefin emulsion, an ethylene vinyl acetate emulsion, or the like is dispersed in water or an aqueous organic solvent.

[0027] The organic solvent is not particularly limited, and examples thereof include various organic solvents such as aromatic hydrocarbons such as toluene, xylene, Solvesso #100, and Solvesso #150; aliphatic hydrocarbons such as hexane, heptane, octane, and decane; and esters such as methyl acetate, ethyl acetate, isopropyl acetate, butyl acetate, amyl acetate, ethyl formate, and butyl propionate.

[0028] Examples of aqueous organic solvents include alcohols such as methanol, ethanol, propanol, and butanol; ketones such as acetone, methyl ethyl ketone, and cyclohexanone; and glycol ethers such as ethylene glycol (mono, di)methyl ether, ethylene glycol (mono, di)ethyl ether, ethylene glycol monopropyl ether, ethylene glycol monoisopropyl ether, monobutyl ether, diethylene glycol (mono, di)methyl ether, diethylene glycol (mono, di)ethyl ether, diethylene glycol monoisopropyl ether, diethylene glycol monobutyl ether, triethylene glycol (mono, di)methyl ether, propylene glycol (mono, di)methyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, and dipropylene glycol (mono, di)methyl ether.

[0029] The heat-sealing agent may contain components other than the heat-sealable resin and solvent, such as wax, filler, antifoaming agent, viscosity modifier, leveling agent, tackifier, preservative, antibacterial agent, rust inhibitor, antioxidant, etc.

[0030] The heat sealing agent can be applied by any known method, such as a roll coater, gravure coater, flexo coater, air doctor coater, blade coater, air knife coater, squeeze coater, impregnation coater, transfer roll coater, kiss coater, curtain coater, cast coater, spray coater, die coater, offset printing machine, screen printing machine, etc. After coating, a drying step in an oven or the like can be performed.

[0031] The thickness of the heat seal layer (the amount of heat sealant applied (solid content)) may be any value. For example, it is 0.5 g / m ２ ~5g / m ２ is.

[0032] The thickness of the second substrate can be selected arbitrarily, but when applied to a packaging material as described below, it is selected in the range of 5 to 500 μm, more preferably 10 to 250 μm, and even more preferably 15 to 100 μm.

[0033] The second substrate may have a vapor-deposited metal layer such as aluminum or a vapor-deposited inorganic layer such as aluminum oxide or silica.

[0034] (Adhesive Layer) The adhesive layer is a layer that bonds the first substrate and the second substrate via the first resin layer described below and any optional layer provided as needed. The adhesive layer can be provided using, for example, but is not limited to, (1) a two-component curing urethane adhesive containing a polyol composition and a polyisocyanate composition (1), (2) a multi-component, solvent-free adhesive containing an oil or fat containing an acid anhydride group and a curing agent having a reactive group that can react with the acid anhydride group, and forming an adhesive layer by the reaction and curing of these (2), (3) an adhesive containing an olefin resin modified with an acid and / or a hydroxyl group as the main component (3), or (4) a polyurethane-based, polyolefin-based, polyethyleneimine-based, or epoxy resin-based anchor coating agent (4).

[0035] (Adhesive (1)) The polyol composition of the adhesive (1) contains polyols such as polyester polyols, polyether polyols, vegetable oil polyols, polyurethane polyols, sugar alcohols, etc. These polyols can also be used in combination of two or more.

[0036] Examples of polyester polyols include polyester polyols which are reaction products of polyhydric alcohols and polycarboxylic acids, and lactone-based polyester polyols obtained by polycondensation reaction of aliphatic polyols with various lactones such as ε-caprolactone. It is preferable to use polyester polyols which are reaction products of polyhydric alcohols and polycarboxylic acids.

[0037] Examples of polyhydric alcohols include aliphatic diols such as ethylene glycol, diethylene glycol, propylene glycol, 1,3-propanediol, 1,2,2-trimethyl-1,3-propanediol, 2,2-dimethyl-3-isopropyl-1,3-propanediol, 1,4-butanediol, 1,3-butanediol, 3-methyl-1,3-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 1,4-bis(hydroxymethyl)cyclohexane, and 2,2,4-trimethyl-1,3-pentanediol;

[0038] aliphatic polyols having three or more functional groups, such as trimethylolethane, trimethylolpropane, glycerin, hexanetriol, and pentaerythritol;

[0039] Examples of such polyether polyols include polyether polyols obtained by ring-opening polymerization of an aliphatic diol or polyol with various cyclic ether bond-containing compounds such as ethylene oxide, propylene oxide, tetrahydrofuran, ethyl glycidyl ether, propyl glycidyl ether, butyl glycidyl ether, phenyl glycidyl ether, and allyl glycidyl ether. These polyether polyols may be used alone or in combination of two or more.

[0040] Examples of polycarboxylic acids include aliphatic dicarboxylic acids such as succinic acid, adipic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, maleic anhydride, fumaric acid, 1,3-cyclopentanedicarboxylic acid, and 1,4-cyclohexanedicarboxylic acid; aromatic dicarboxylic acids such as orthophthalic acid, isophthalic acid, terephthalic acid, 1,4-naphthalenedicarboxylic acid, 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, naphthalic acid, biphenyldicarboxylic acid, and 1,2-bis(phenoxy)ethane-p,p'-dicarboxylic acid; and anhydrides or ester-forming derivatives of these aliphatic or dicarboxylic acids; and polybasic acids such as p-hydroxybenzoic acid, p-(2-hydroxyethoxy)benzoic acid, and ester-forming derivatives of these dihydroxycarboxylic acids, and dimer acid, and these may be used alone or in combination of two or more.

[0041] The molecular weight of the polyester polyol is not particularly limited, but is, for example, 250 g / mol to 20,000 g / mol. The hydroxyl value of the polyester polyol is not particularly limited, but is, for example, 5 mgKOH / g to 500 mgKOH / g.

[0042] Examples of polyether polyols include those obtained by addition polymerization of alkylene oxides such as ethylene oxide, propylene oxide, butylene oxide, styrene oxide, epichlorohydrin, tetrahydrofuran, and cyclohexylene in the presence of a polymerization initiator.

[0043] Examples of the polymerization initiator include glycols such as ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, methylpentanediol, dimethylbutanediol, butylethylpropanediol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, bishydroxyethoxybenzene, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, and triethylene glycol;

[0044] trifunctional or tetrafunctional aliphatic alcohols such as glycerin, trimethylolpropane, pentaerythritol, and triols of polypropylene glycol;

[0045] Examples thereof include primary or secondary alkylamines such as ethylamine and diethylamine, amine compounds having a plurality of amino groups such as methylenediamine and ethylenediamine, and amine compounds having an active hydrogen group such as primary or secondary alkanolamines such as monoethanolamine and diethanolamine.

[0046] The molecular weight of the polyether polyol can be adjusted appropriately, but is, for example, 100 g / mol to 8000 g / mol. The hydroxyl value of the polyether polyol can be adjusted appropriately, but is, for example, 10 mgKOH / g to 1200 mgKOH / g.

[0047] Examples of the vegetable oil polyol include castor oil, dehydrated castor oil, hardened castor oil which is a hydrogenated castor oil, and an alkylene oxide 5 to 50 mole adduct of castor oil.

[0048] Polyurethane polyol is a reaction product of a low-molecular-weight or high-molecular-weight polyol and a polyisocyanate compound. The low-molecular-weight or high-molecular-weight polyol may be the same as the polyhydric alcohol exemplified as the raw material for polyester polyol. The polyisocyanate compound may be the same as the polyisocyanate that can be contained in the isocyanate composition described below.

[0049] Examples of sugar alcohols include pentaerythritol, sucrose, xylitol, sorbitol, isomalt, lactitol, maltitol, and mannitol.

[0050] The polyisocyanate composition contains a polyisocyanate compound having multiple isocyanate groups. The polyisocyanate compound is not particularly limited, and examples thereof include aromatic diisocyanates, araliphatic diisocyanates, aliphatic diisocyanates, alicyclic diisocyanates, and biuret, nurate, adduct, allophanate, carbodiimide-modified, and uretdione-modified products of these diisocyanates, as well as urethane prepolymers obtained by reacting these polyisocyanates with polyols, and these can be used alone or in combination.

[0051] Examples of aromatic diisocyanates include, but are not limited to, 2,2'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, polymethylene polyphenyl polyisocyanate (also referred to as polymeric MDI or crude MDI), 1,3-phenylene diisocyanate, 4,4'-diphenyl diisocyanate, 1,4-phenylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4'-toluidine diisocyanate, 2,4,6-triisocyanate toluene, 1,3,5-triisocyanate benzene, dianisidine diisocyanate, 4,4'-diphenyl ether diisocyanate, and 4,4',4"-triphenylmethane triisocyanate.

[0052] The araliphatic diisocyanate means an aliphatic isocyanate having one or more aromatic rings in the molecule, and examples thereof include, but are not limited to, m- or p-xylylene diisocyanate (also known as XDI), α,α,α',α'-tetramethylxylylene diisocyanate (also known as TMXDI), and the like.

[0053] Examples of aliphatic diisocyanates include trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate (also known as HDI), pentamethylene diisocyanate, 1,2-propylene diisocyanate, 2,3-butylene diisocyanate, 1,3-butylene diisocyanate, dodecamethylene diisocyanate, and 2,4,4-trimethylhexamethylene diisocyanate, but are not limited to these.

[0054] Examples of alicyclic diisocyanates include 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate, isophorone diisocyanate (also known as IPDI), 1,3-cyclopentane diisocyanate, 1,3-cyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, methyl-2,4-cyclohexane diisocyanate, methyl-2,6-cyclohexane diisocyanate, 4,4'-methylenebis(cyclohexyl isocyanate), and 1,4-bis(isocyanatomethyl)cyclohexane, but are not limited to these.

[0055] The polyol used in the synthesis of the urethane prepolymer may be the same as the polyhydric alcohols exemplified as raw materials for the polyester polyols described above, and may be used alone or in combination of two or more. It is preferable to use at least one polyalkylene glycol or polyester polyol having a molecular weight of 200 to 3000 g / mol.

[0056] The adhesive (1) used in the present invention may be solvent-based or solventless. In this specification, a solvent-based adhesive refers to a polyol composition and a polyisocyanate composition that contain highly soluble organic solvents such as esters such as ethyl acetate, butyl acetate, and cellosolve acetate; ketones such as acetone, methyl ethyl ketone, isobutyl ketone, and cyclohexanone; ethers such as tetrahydrofuran and dioxane; aromatic hydrocarbons such as toluene and xylene; halogenated hydrocarbons such as methylene chloride and ethylene chloride; dimethyl sulfoxide and dimethyl sulfamide; and a solventless adhesive refers to a composition that is substantially free of these organic solvents. When the organic solvents used as reaction media during the production of the components of the polyol composition and polyisocyanate composition or their raw materials cannot be completely removed, leaving trace amounts of organic solvent remaining in the polyol composition and polyisocyanate composition, the adhesive is considered to be substantially free of organic solvent. Furthermore, when the polyol composition contains a low-molecular-weight alcohol, the low-molecular-weight alcohol reacts with the polyisocyanate composition to become part of the coating film, and therefore does not need to be volatilized after coating. Therefore, this type of adhesive is also treated as a solvent-free adhesive, and the low-molecular-weight alcohol is not considered an organic solvent.

[0057] The adhesive (1) used in the present invention may contain components other than the above-mentioned components, such as a urethanization catalyst, an acid anhydride, a coupling agent, a pigment, a plasticizer, a phosphoric acid derivative, etc. These components may be contained in either or both of the polyol composition and the polyisocyanate composition, or may be prepared separately from these and then mixed with the polyol composition and the polyisocyanate composition immediately before application of the adhesive (1).

[0058] The adhesive (1) is preferably used by blending the polyisocyanate composition (Y) with the polyol composition (X) so that the ratio [NCO] / [OH] of the number of moles of isocyanate groups [NCO] to the number of moles of hydroxyl groups [OH] is 0.5 to 3.0.

[0059] In one embodiment of the present invention, the adhesive layer is a cured coating film of such adhesive (1). The adhesive is applied to either the first substrate or the second substrate, either directly or via a first resin layer or any other layer that is optionally provided, and then the substrate is laminated to the other substrate, followed by aging treatment to form the adhesive layer. As an example, the aging temperature is room temperature to 70°C, and the aging time is 6 to 240 hours. The amount of adhesive (1) applied is adjusted as appropriate, but as an example, it is 1 g / m ２ 5g / m or more ２ The following is the result.

[0060] (Adhesive (2)) The fat or oil containing an acid anhydride group of adhesive (2) can be obtained, for example, by adding an acid anhydride group-containing compound to fat or oil. Fat or oil containing an acid anhydride group is preferably obtained by introducing an acid anhydride group into fat or oil containing a double bond derived from an unsaturated fatty acid in its chemical structure.

[0061] Oils and fats containing double bonds derived from unsaturated fatty acids in their chemical structure are preferably drying oils (iodine value >130) and / or semi-drying oils (iodine value 100-130). Examples of vegetable oils include tung oil, linseed oil, perilla oil, safflower oil, dehydrated castor oil, safflower oil, soybean oil, rapeseed oil, sunflower oil, sesame oil, rice oil, cottonseed oil, corn oil, tall oil, poppy oil, walnut oil, and pine seed oil. Examples of animal oils include fish oils (sardine oil, saury oil, herring oil, etc.). In addition, in the present invention, recycled vegetable oils recovered and recycled after being used for cooking, such as tempura oil, can also be used. Among these oils and fats, tung oil, soybean oil, and linseed oil are preferred due to their ease of availability. Furthermore, oils and fats of the grade known as "shirarein oil" or "salad oil," which are refined so as not to crystallize even at low temperatures for long periods of time, are preferably used.

[0062] As the acid anhydride group-containing compound used for introducing the acid anhydride group, a compound having a double bond in the molecule can be used, and examples thereof include maleic anhydride, citraconic anhydride, and tetrahydrophthalic anhydride. Among these, maleic anhydride is preferred for use in view of ease of introduction and the reactivity of the acid anhydride group.

[0063] The amount of acid anhydride groups introduced into fats and oils can be adjusted as appropriate. To explain the case of introducing maleic anhydride as an example, the amount of maleic anhydride introduced is, for example, 19 to 34 g (0.19 to 0.35 mol) of maleic anhydride, more preferably 22 to 29 g (0.22 to 0.30 mol) per 100 g of fats and oils.

[0064] Various acids may be used in combination with fats and oils containing an acid anhydride group, such as hydroxycarboxylic acids such as citric acid, isocitric acid, malic acid, and tartaric acid, phosphoric acid, monoalkyl phosphate esters, dialkyl phosphate esters, acetic acid, alkyl (C2-18) monocarboxylic acids, and dimer acids. These may be added when the acid anhydride is added to the fats and oils, or may be added after the addition reaction is complete.

[0065] Examples of curing agents having a reactive group capable of reacting with an acid anhydride group include nitrogen-containing compounds such as tertiary amine-containing polyols, amino alcohols, amide polyols, and polyamines, as well as compounds having a hydroxyl group. Tertiary amine-containing polyols are particularly preferred because they allow for easy adjustment of the balance between the reactivity with oils and fats containing an acid anhydride group and the physical properties of the film formed.

[0066] It is particularly preferable that the tertiary amine-containing polyol has 2 to 6 hydroxyl groups. It is sufficient that the tertiary amine-containing polyol has one or more tertiary amino groups, but it is preferable that the tertiary amine-containing polyol has 1 to 2 tertiary amino groups. Specific examples include polypropylene glycol ethylenediamine ether, tri(1,2-polypropylene glycol)amine, N-ethyldiethanolamine, N-methyl-N-hydroxyethyl-N-hydroxyethoxyethylamine, pentakishydroxypropyldiethylenetriamine, and tetrakishydroxypropylethylenediamine.

[0067] The tertiary amine-containing polyol may be a commercially available product, such as TE-360 (a tertiary amine-containing trifunctional polyol manufactured by Guodo Chemical Co., Ltd. (China)), TD-401 (a tertiary amine-containing tetrafunctional polyol manufactured by Guodo Chemical Co., Ltd. (China), EDP-300, or EDP-450 (all of which are tertiary amine-containing tetrafunctional polyols manufactured by Adeka Corporation).

[0068] Examples of amino alcohols having both a primary or secondary amino group and a hydroxyl group in one molecule include monomethanolamine, N-methylmethanolamine, N-ethylmethanolamine, dimethanolamine, monoethanolamine, N-methylethanolamine, N-ethylethanolamine, and diethanolamine.

[0069] Examples of amide polyols include polyesteramide polyols, and polyesteramide polyols obtained by using, as a raw material, an aliphatic diamine having an amino group, such as ethylenediamine, propylenediamine, or hexamethylenediamine, in the esterification reaction of the polyester polyol.

[0070] The polyamine is not particularly limited, and any known polyamine having a primary and / or secondary amino group can be used. The polyamine may also contain a tertiary amine.

[0071] More specifically, alkylene diamines such as ethylenediamine, propylenediamine, trimethylenediamine, tetramethylenediamine, and hexamethylenediamine, and aliphatic diamines having 2 to 18 carbon atoms, such as polyalkylene diamines such as diethylenetriamine, iminobispropylamine, bis(hexamethylene)triamine, triethylenetetramine, tetraethylenepentamine, and pentaethylenehexamine,

[0072] alkyl (having 1 to 4 carbon atoms) or hydroxyalkyl (having 2 to 4 carbon atoms) substituted aliphatic diamines such as dialkylaminopropylamines having 1 to 3 carbon atoms, trimethylhexamethylenediamine, aminoethylethanolamine, 2,5-dimethyl-2,5-hexamethylenediamine and methyliminobispropylamine;

[0073] alicyclic diamines having 4 to 15 carbon atoms, such as 1,3-diaminocyclohexane, isophoronediamine, menthenediamine, and 4,4'-methylenedicyclohexanediamine (hydrogenated methylenedianiline); alicyclic or heterocyclic ring-containing aliphatic diamines, such as piperazine, N-aminoethylpiperazine, 1,4-diaminoethylpiperazine, and 3,9-bis(3-aminopropyl)-2,4,8,10-tetraoxaspiro[5,5]undecane;

[0074] aromatic ring-containing aliphatic amines having 8 to 15 carbon atoms, such as xylylenediamine and tetrachloro-p-xylylenediamine;

[0075] unsubstituted aromatic diamines having 6 to 20 carbon atoms, such as 1,2-, 1,3-, or 1,4-phenylenediamine, 2,4'- and 4,4'-diphenylmethanediamine, crude diphenylmethanediamine (polyphenylpolymethylenepolyamine), diaminodiphenylsulfone, benzidine, thiodianiline, 2,6-diaminopyridine, m-aminobenzylamine, triphenylmethane-4,4',4"-triamine, and naphthylenediamine;

[0076] aromatic diamines having a nucleus-substituted alkyl group having 1 to 4 carbon atoms, such as 2,4- or 2,6-tolylenediamine, crude tolylenediamine, diethyltolylenediamine, 4,4'-diamino-3,3'-dimethyldiphenylmethane, 4,4'-bis(o-toluidine), dianisidine, diaminoditolyl sulfone, 1,3-dimethyl-2,4-diaminobenzene, 2,3-dimethyl-1,4-diaminonaphthalene and 4,4'-diamino-3,3'-dimethyldiphenylmethane, and mixtures of these isomers in various ratios;

[0077] aromatic diamines having a nucleus-substituted electron-withdrawing group (halogen atoms such as fluorine, chlorine, bromine, and iodine; alkoxy groups such as methoxy and ethoxy; nitro group, etc.), such as methylenebis-o-chloroaniline, 4-chloro-o-phenylenediamine, 2-chloro-1,4-phenylenediamine, 3-amino-4-chloroaniline, 4-bromo-1,3-phenylenediamine, 2,5-dichloro-1,4-phenylenediamine, 5-nitro-1,3-phenylenediamine, and 3-dimethoxy-4-aminoaniline;

[0078] Aromatic diamines having a secondary amino group, such as 4,4'-di(methylamino)diphenylmethane and 1-methyl-2-methylamino-4-aminobenzene (the -NH ２ a part or all of which is substituted with -NH-R' (R' is an alkyl group; for example, a lower alkyl group such as a methyl group or an ethyl group),

[0079] low-molecular-weight polyamide polyamines obtained by condensing dicarboxylic acids such as dimer acids with polyamines such as the alkylenediamines and polyalkylene polyamines described above under conditions in which the amino groups are in excess relative to the acid groups (2 moles or more of amino groups per mole of acid groups);

[0080] Examples include polyether polyamines, which are hydrogenated cyanoethylated polyether polyols such as polyalkylene glycols.

[0081] Among these, polyamidoamines and polyether polyamines are preferably used because they can form coatings with excellent strength.

[0082] Commercially available polyamines can also be used, such as JEFFAMINE T-403, JEFFAMINE D-230, and JEFFAMINE D-400 (all of which are polyether polyamines manufactured by Huntsman Chemical Co., USA).

[0083] In the case of polyether polyamines, those which are preferably bifunctional or trifunctional and have a molecular weight of 200 to 5,000, more preferably 200 to 1,500, are preferably used.

[0084] As the compound containing a hydroxyl group, for example, a compound containing two or more hydroxyl groups on average in the molecule can be suitably used, and examples thereof include polymer polyols selected from polyester polyols, polyether polyols, polyurethane polyols, polyether ester polyols, polyester (polyurethane) polyols, polyether (polyurethane) polyols, acrylic polyols, polycarbonate polyols, polyhydroxyl alkanes, castor oil, and mixtures thereof.

[0085] The polyester polyol may be the same as those exemplified as components of the polyol composition of adhesive (1), and preferably has a number average molecular weight of 400 to 2000 and a hydroxyl value of 60 to 300.

[0086] The polyether polyols and polyurethane polyols that can be used are the same as those exemplified as components of the polyol composition of adhesive (1). Examples of polyether ester polyols include polyether ester polyols obtained by reacting the above-mentioned polyether polyols with dibasic acids such as terephthalic acid, isophthalic acid, phthalic anhydride, adipic acid, azelaic acid, sebacic acid, and dimer acid, or their dialkyl esters, or mixtures thereof.

[0087] Examples of polycarbonate polyols include those obtained by reacting one or more glycols selected from ethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,9-nonanediol, 1,8-nonanediol, neopentyl glycol, diethylene glycol, dipropylene glycol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, bisphenol A, and hydrogenated bisphenol A with dimethyl carbonate, diphenyl carbonate, ethylene carbonate, phosgene, or the like.

[0088] Acrylic polyols can be obtained by copolymerizing hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxybutyl acrylate, or their corresponding methacrylic acid derivatives, each containing one or more hydroxyl groups per molecule, with, for example, acrylic acid, methacrylic acid, or an ester thereof. Examples of polyhydroxyalkanes include liquid rubbers obtained by copolymerizing butadiene or butadiene with acrylamide, etc.

[0089] Examples of polyhydroxyalkanes include glycols (diols) such as ethylene glycol, propylene glycol, diethylene glycol, 1,4-butanediol, and 1,6-hexanediol, and trihydric or tetrahydric alcohols such as glycerin, trimethylolpropane, and pentaerythritol.

[0090] As the compound containing a hydroxyl group, it is preferable to use at least one polyester polyol, since the reactivity of the hydroxyl group is high and the curability can be improved.

[0091] The curing agent preferably contains at least one nitrogen-containing compound. Only one nitrogen-containing compound may be used, or multiple nitrogen-containing compounds may be used in combination. The nitrogen-containing compound not only contributes to the formation of a cured adhesive as a curing agent, but also, when the curing agent contains a hydroxyl group-containing oil-containing compound, the nitrogen contained in the structure acts as a catalyst that promotes the reaction between the acid anhydride group and the hydroxyl group, thereby improving the curing rate.

[0092] The fats and oils containing acid anhydride groups and the curing agent are preferably used such that the molar ratio of the acid anhydride groups in the fats and oils to the functional groups reactive with the acid anhydride groups contained in the curing agent (acid anhydride groups / functional groups reactive with acid anhydride groups) is in the range of 0.5 to 1.5, more preferably 0.8 to 1.25.

[0093] When the curing agent contains a nitrogen-containing compound, the amount of the curing agent used is preferably such that the molar ratio of nitrogen in the nitrogen-containing compound to the acid anhydride group in the oil or fat (nitrogen / acid anhydride group) is in the range of 0.5 to 0.8, more preferably 0.5 to 0.65.

[0094] Preferred combinations of fats and oils containing an acid anhydride group and curing agents include a combination of fats and oils containing maleic anhydride-modified tung oil with a curing agent containing a polyester polyol and a tertiary amine-containing polyol, a combination of fats and oils containing maleic anhydride-modified soybean oil with a curing agent containing a polyester polyol and a polyether polyamine, and a combination of fats and oils containing maleic anhydride-modified soybean oil and tung oil with a curing agent containing a polyester polyol, a polyether polyamine, and a tertiary amine-containing polyol.

[0095] The adhesive (2) may contain a polycarbodiimide compound, if necessary. The polycarbodiimide compound reacts with the carboxylic acid produced by the reaction between the oil or fat containing an acid anhydride group and the curing agent to form a denser cured adhesive, thereby improving adhesive strength.

[0096] The polycarbodiimide compound is not particularly limited and any known polycarbodiimide compound can be used. The molecular weight of the polycarbodiimide compound, converted into number average molecular weight, is preferably in the range of 1,000 to 5,000, more preferably in the range of 2,000 to 4,000.

[0097] The carbodiimide compound can be obtained as a commercially available product, for example, Carbodilite V02B (solid content concentration 100%, carbodiimide equivalent weight 600), Carbodilite V05 (solid content concentration 100%, carbodiimide equivalent weight 262), Carbodilite V04PF (solid content concentration 100%, carbodiimide equivalent weight 336), Carbodilite V05S (solid content concentration 90% by mass, carbodiimide group equivalent weight 291 (solid content equivalent weight 262)). ), Carbodilite V07 (solid content concentration 50% by mass, carbodiimide group equivalent 404 (solid content equivalent 202)), Carbodilite V09GB (solid content concentration 70% by mass, carbodiimide group equivalent 298 (solid content equivalent 209) (all manufactured by Nisshinbo Chemical Inc.), and the like, with V02B and V05 being preferred. The carbodiimide-containing component may be contained alone or in combination of two or more types.

[0098] When a polycarbodiimide compound is used, it is preferable to keep the amount used as small as possible, since the polycarbodiimide compound has a high viscosity and may affect the coating suitability.

[0099] The adhesive (2) may contain components other than the above-mentioned anhydride group-containing oil and curing agent. Such components include, but are not limited to, catalysts, coupling agents, acid anhydrides, hydroxycarboxylic acids, oxygen scavengers, phosphoric acids, pigments, tackifiers, stabilizers (antioxidants, heat stabilizers, UV absorbers, etc.), plasticizers, antistatic agents, lubricants, antiblocking agents, colorants, crystal nucleating agents, antifoaming agents, leveling agents, etc. These components may be contained in only one of the first composition and the second composition described below, or in both.

[0100] In one embodiment of the present invention, the adhesive layer is a cured coating of such adhesive (2). The adhesive is applied to either the first substrate or the second substrate, either directly or via a first resin layer or any other layer that is optionally provided, and then the substrate is laminated to the other substrate, followed by aging treatment to form the adhesive layer. As an example, the aging temperature is room temperature to 70°C, and the aging time is 6 to 240 hours. The amount of adhesive (2) applied is adjusted as appropriate, but as an example, it is 1 g / m ２ 5g / m or more ２ The following is the result.

[0101] (Adhesive (3)) Examples of the olefin-based resin modified with an acid and / or a hydroxyl group used in the adhesive (3) include a copolymer of an olefin-based monomer and a polymerizable monomer having an acid group (or an acid anhydride group) and / or a hydroxyl group, and a resin obtained by graft-modifying an olefin resin with a polymerizable monomer having an acid group (or an acid anhydride group) and / or a hydroxyl group.

[0102] Examples of the olefin resin having an acid group and / or an acid anhydride group include a copolymer of an olefin monomer and an ethylenically unsaturated carboxylic acid or an ethylenically unsaturated carboxylic acid anhydride, and a resin in which a polyolefin is graft-modified with an ethylenically unsaturated carboxylic acid or an ethylenically unsaturated carboxylic acid anhydride.

[0103] Examples of the olefin-based monomer include olefins having 2 to 8 carbon atoms, such as ethylene, propylene, isobutylene, 1-butene, 4-methyl-1-pentene, hexene, vinylcyclohexane, etc. Among these, olefins having 2 to 8 carbon atoms are preferred because they provide particularly good adhesive strength, and it is preferable to use ethylene, propylene, and 1-butene.

[0104] Examples of the ethylenically unsaturated carboxylic acid or ethylenically unsaturated carboxylic acid anhydride used in copolymerization with an olefin-based monomer include acrylic acid, methacrylic acid, maleic acid, itaconic acid, citraconic acid, mesaconic acid, maleic anhydride, 4-methylcyclohex-4-ene-1,2-dicarboxylic anhydride, bicyclo[2.2.2]oct-5-ene-2,3-dicarboxylic anhydride, 1,2,3,4,5,8,9,10-octahydronaphthalene Examples of suitable maleic anhydrides include methyl-bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic anhydride, 2-octa-1,3-diketospiro[4.4]non-7-ene, bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic anhydride, maleopimaric acid, tetrahydrophthalic anhydride, methyl-bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic anhydride, methyl-norbornene-5-ene-2,3-dicarboxylic anhydride, and norborn-5-ene-2,3-dicarboxylic anhydride. Among these, maleic anhydride is particularly preferred because of its excellent reactivity with olefin-based monomers, the excellent reactivity of the acid anhydride after copolymerization, and the low molecular weight of the compound itself, resulting in a high functional group concentration when copolymerized. These may be used alone or in combination of two or more.

[0105] In addition to the olefinic monomer, ethylenically unsaturated carboxylic acid or ethylenically unsaturated carboxylic acid anhydride, other compounds having an ethylenically unsaturated group, such as styrene, butadiene, isoprene, etc. may be used in combination.

[0106] Examples of polyolefins used when synthesizing an acid-modified olefin resin by graft modification include homopolymers and copolymers of olefins having 2 to 8 carbon atoms, and copolymers of olefins having 2 to 8 carbon atoms with other monomers. Specific examples include polyethylenes such as high-density polyethylene (HDPE), low-density polyethylene (LDPE), and linear low-density polyethylene resins; polypropylene; polyisobutylene; poly(1-butene), poly(4-methyl-1-pentene), polyvinylcyclohexane; α-olefin copolymers such as ethylene-propylene block copolymers, ethylene-propylene random copolymers, ethylene-1-butene copolymers, ethylene-4-methyl-1-pentene copolymers, and ethylene-hexene copolymers; ethylene-vinyl acetate copolymers, ethylene-methyl methacrylate copolymers, ethylene-vinyl acetate-methyl methacrylate copolymers, propylene-1-butene copolymers, and ethylene-propylene-1-butene copolymers. Among these, homopolymers of olefins having 2 to 8 carbon atoms and copolymers of two or more olefins having 2 to 8 carbon atoms are preferred in terms of particularly good adhesive strength, and ethylene-propylene copolymers, ethylene-1-butene copolymers, propylene-1-butene copolymers, and ethylene-propylene-1-butene copolymers are particularly preferred.

[0107] The ethylenically unsaturated carboxylic acid or ethylenically unsaturated carboxylic acid anhydride used for graft-modification with polyolefin may be the same as those exemplified above. Maleic anhydride is preferred because it has high reactivity of functional groups after graft-modification and also increases the functional group concentration of the graft-modified polyolefin. These may be used alone or in combination of two or more.

[0108] The olefin resin having an acid group and / or an acid anhydride group preferably has an acid value of 1 to 200 mgKOH / g.

[0109] Examples of the olefin resin having a hydroxyl group include a copolymer of a polyolefin with a hydroxyl group-containing (meth)acrylic ester or a hydroxyl group-containing vinyl ether, and a resin obtained by graft-modifying a polyolefin with a hydroxyl group-containing (meth)acrylic ester or a hydroxyl group-containing vinyl ether. The polyolefin may be the same as that used in the synthesis of the olefin resin having an acid group and / or an acid anhydride group.

[0110] Examples of hydroxyl group-containing (meth)acrylic acid esters include hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, glycerol (meth)acrylate, lactone-modified hydroxyethyl (meth)acrylate, polyethylene glycol mono(meth)acrylate, polypropylene glycol mono(meth)acrylate, etc. Examples of hydroxyl group-containing vinyl ethers include 2-hydroxyethyl vinyl ether, diethylene glycol monovinyl ether, 4-hydroxybutyl vinyl ether, etc.

[0111] The olefin resin having a hydroxyl group preferably has a hydroxyl value of 1 to 200 mgKOH / g.

[0112] The weight average molecular weight of the olefin resin modified with an acid and / or a hydroxyl group is preferably 40,000 or more and 250,000 or less.

[0113] The melting point of the olefin resin modified with an acid and / or a hydroxyl group is preferably 40° C. or higher, more preferably 50° C. or higher, and even more preferably 60° C. or higher. The melting point of the olefin resin (A) is preferably 120° C. or lower, more preferably 90° C. or lower, and even more preferably 85° C. or lower.

[0114] The adhesive (3) is preferably used in combination with a curing agent. The curing agent is not particularly limited, and any compound capable of crosslinking acid groups, acid anhydride groups, and / or hydroxyl groups can be used. Specifically, at least one compound selected from the group consisting of an isocyanate compound, an epoxy compound, a carbodiimide compound, a silane coupling agent, and a metal compound is preferred.

[0115] The isocyanate compound may be the same as those exemplified for the adhesive (1). The isocyanate compounds may be used alone or in combination of two or more.

[0116] The epoxy compound is not particularly limited as long as it is a compound having an epoxy group in the molecule, and examples thereof include polyglycidyl ether type epoxy resins of aliphatic polyols such as ethylene glycol, propylene glycol, hexanediol, neopentyl glycol, trimethylolethane, trimethylolpropane, pentaerythritol, glycerin, diglycerin, sorbitol, spiroglycol, and hydrogenated bisphenol A; bisphenol type epoxy resins such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, and bisphenol AD ​​type epoxy resin; aromatic epoxy resins such as novolac type epoxy resins which are glycidyl ethers of phenol novolac resin and cresol novolac resin; polyglycidyl ethers of polyols which are ethylene oxide or propylene oxide adducts of aromatic polyhydroxy compounds such as bisphenol A, bisphenol F, bisphenol S, and bisphenol AD; Polyglycidyl ether type epoxy resins of polyether polyols such as polyethylene glycol, polypropylene glycol, or polytetramethylene glycol; cycloaliphatic type polyepoxy resins such as bis(3,4-epoxycyclohexylmethyl)adipate and 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexylcarboxylate; polyglycidyl ester type epoxy resins of polycarboxylic acids such as propanetricarboxylic acid, butanetetracarboxylic acid, adipic acid, phthalic acid, terephthalic acid, or trimellitic acid; bisepoxy resins of hydrocarbon dienes such as butadiene, hexadiene, octadiene, dodecadiene, cyclooctadiene, α-pinene, or vinylcyclohexene; epoxy resins of diene polymers such as polybutadiene or polyisoprene; glycidylamine type epoxy resins such as tetraglycidyldiaminodiphenylmethane, triglycidyl paraaminophenol, tetraglycidyl bisaminomethylcyclohexane, diglycidylaniline, and tetraglycidyl metaxylylenediamine; Examples of the epoxy resin include epoxy resins containing heterocycles such as triazine and hydantoin. These epoxy resins may be used alone or in combination of two or more.

[0117] Examples of the carbodiimide compound include N,N'-di-o-toluylcarbodiimide, N,N'-diphenylcarbodiimide, N,N'-di-2,6-dimethylphenylcarbodiimide, N,N'-bis(2,6-diisopropylphenyl)carbodiimide, N,N'-dioctyldecylcarbodiimide, N-triyl-N'-cyclohexylcarbodiimide, N,N'-di-2,2-tert.-butylphenylcarbodiimide, N-triyl-N'-phenylcarbodiimide, N,N'-di-p-aminophenylcarbodiimide, N,N'-di-p-hydroxyphenylcarbodiimide, N,N'-di-cyclohexylcarbodiimide, and N,N'-di-p-toluylcarbodiimide.

[0118] Examples of silane coupling agents include aminosilanes such as γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, N-β(aminoethyl)-γ-aminopropyltrimethoxysilane, N-β(aminoethyl)-γ-aminopropyltrimethyldimethoxysilane, and N-phenyl-γ-aminopropyltrimethoxysilane; epoxysilanes such as β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, and γ-glycidoxypropyltriethoxysilane; vinylsilanes such as vinyltris(β-methoxyethoxy)silane, vinyltriethoxysilane, vinyltrimethoxysilane, and γ-methacryloxypropyltrimethoxysilane; hexamethyldisilazane, γ-mercaptopropyltrimethoxysilane, and the like.

[0119] The metal compound can be used without any particular limitation as long as it forms an ionic crosslink with the olefin-based resin modified with an acid and / or a hydroxyl group. Specifically, it is a compound containing a metal ion, and examples thereof include metal oxides, hydroxides, carbonates, bicarbonates, acetates, formates, methoxides, and ethoxides. Examples of metal ions include Li ＋ , Na ＋ , K. ＋ , Ag ＋ , Cu ＋ monovalent ions such as Cu２＋ , Ba ２＋ , Zn ２＋ , Fe ２＋ These metal ions may be used in combination as needed.

[0120] Other usable compounds include aziridine group-containing compounds, oxazolines, amino resins, etc. Examples of the aziridine group-containing compound include N,N'-hexamethylene-1,6-bis(1-aziridinecarboxamide), N,N'-diphenylmethane-4,4'-bis(1-aziridinecarboxamide), trimethylolpropane-tri-β-aziridinylpropionate), N,N'-toluene-2,4-bis(1-aziridinecarboxamide), triethylenemelamine, trimethylolpropane-tri-β(2-methylaziridine)propionate, bisisophthaloyl-1-2-methylaziridine, tri-1-aziridinylphosphine oxide, and tris-1-2-methylaziridinephosphine oxide.

[0121] Examples of oxazolines include monooxazoline compounds such as 2-oxazoline, 2-methyl-2-oxazoline, 2-phenyl-2-oxazoline, 2,5-dimethyl-2-oxazoline, and 2,4-diphenyl-2-oxazoline, as well as 2,2'-(1,3-phenylene)-bis(2-oxazoline), 2,2'-(1,2-ethylene)-bis(2-oxazoline), 2,2'-(1,4butylene)-bis(2-oxazoline), and 2,2'-(1,4-phenylene)-bis(2-oxazoline).

[0122] Examples of the amino resin include melamine resin, benzoguanamine resin, and urea resin.

[0123] The amount of curing agent in the adhesive (3) is preferably 0.01 parts by mass or more, more preferably 0.1 parts by mass or more, and even more preferably 0.5 parts by mass or more, per 100 parts by mass of the acid- and / or hydroxyl-modified olefin-based resin. The amount of curing agent is preferably 50 parts by mass or less, more preferably 35 parts by mass or less, and even more preferably 25 parts by mass or less, per 100 parts by mass of the acid- and / or hydroxyl-modified olefin-based resin.

[0124] In addition to the above components, the adhesive (3) can be blended with an organic solvent to ensure fluidity and develop appropriate coatability. Such organic solvents are not particularly limited as long as they can be removed by evaporation through heating in the drying step during adhesive application, and examples include aromatic organic solvents such as toluene and xylene; aliphatic organic solvents such as n-hexane and n-heptane; alicyclic organic solvents such as cyclohexane and methylcyclohexane; halogenated organic solvents such as trichloroethylene, dichloroethylene, chlorobenzene and chloroform; ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone; ester solvents such as ethyl acetate and butyl acetate; ethanol, methanol, n-propanol, 2-propanol (isopropyl alcohol), and the like. alcohol-based solvents such as diethanol, butanol, and hexanol; ether-based solvents such as diisopropyl ether, butyl cellosolve, tetrahydrofuran, dioxane, and butyl carbitol; glycol ether-based solvents such as diethylene glycol monomethyl ether, triethylene glycol monomethyl ether, and propylene glycol monomethyl ether; and glycol ester-based solvents such as ethylene glycol monomethyl ether acetate, propylene glycol monomethyl ether acetate, and diethylene glycol monoethyl ether acetate. These may be used alone or in combination of two or more.

[0125] It is preferable to use a mixed solvent of an alicyclic organic solvent and an ester solvent. In particular, when an olefin resin having an acid group, an acid anhydride group, and / or a hydroxyl group is used, it is preferable to use a mixed solvent of methylcyclohexane and ethyl acetate because of its excellent solubility.

[0126] The amount of organic solvent used is preferably such that the proportion of the olefin resin relative to the total mass of the olefin resin having an acid anhydride group and / or a hydroxyl group and the organic solvent is 10 to 30 mass %, which allows for an adhesive with excellent coatability and wettability to substrates.

[0127] The adhesive (3) may contain various additives, such as tackifiers, plasticizers, thermoplastic elastomers, reactive elastomers, phosphate compounds, silane coupling agents, adhesion promoters, catalysts, leveling agents, inorganic fine particles such as colloidal silica and alumina sol, polymethyl methacrylate organic fine particles, defoamers, anti-sagging agents, wetting and dispersing agents, viscosity modifiers, UV absorbers, metal deactivators, peroxide decomposers, flame retardants, reinforcing agents, lubricants, rust inhibitors, fluorescent brighteners, inorganic heat absorbers, flame retardants, antistatic agents, dehydrating agents, etc. The content of these additives may be adjusted as appropriate within a range that does not impair the functionality of the adhesive.

[0128] In one embodiment of the present invention, the adhesive layer is a cured coating of such adhesive (3). The adhesive is applied to either the first substrate or the second substrate, either directly or via a first resin layer or any other layer that is optionally provided, and then the substrate is laminated to the other substrate, followed by aging treatment to form the adhesive layer. As an example, the aging temperature is room temperature to 70°C, and the aging time is 6 to 240 hours. The amount of adhesive (3) applied is adjusted as appropriate, but as an example, it is 1 g / m ２ 5g / m or more ２ The following is the result.

[0129] (Anchor Coating Agent (4)) The adhesive layer may be formed from an anchor coating agent (4) used in a general extrusion lamination method. Examples of such anchor coating agents (4) include polyurethane-based, polyolefin-based, polyethyleneimine-based, and epoxy resin-based anchor coating agents. After the anchor coating agent (4) is applied to the first substrate via the first resin layer and any other layer that may be provided, the resin material of the second substrate is extruded. An example of the resin material of the second substrate that is extruded at this time is a polyethylene resin.

[0130] The anchor coating agent (4) can be applied by a coating method such as roll coating, gravure roll coating, or kiss coating, or by a printing method. The thickness of the adhesive layer formed by the anchor coating agent (4) is, for example, from 0.05 μm to 3.0 μm, preferably from 0.1 μm to 2.0 μm, and more preferably from 0.2 μm to 1.0 μm.

[0131] (First Resin Layer) The first resin layer is a layer disposed between the first substrate and the adhesive layer, and contains a first vinyl alcohol polymer and a first polyalkyleneimine.

[0132] The first vinyl alcohol polymer is a hydrolyzate of a vinyl ester homopolymer or copolymer and may be obtained by a known, commonly used method, or may be a reaction product of a vinyl ester homopolymer or copolymer hydrolyzate and an aldehyde and may be obtained by a known, commonly used method.

[0133] Examples of vinyl esters include vinyl formate, vinyl acetate, vinyl propionate, vinyl butyrate, vinyl isobutyrate, vinyl pivalate, vinyl versatate, vinyl caproate, vinyl caprylate, vinyl laurate, vinyl palmitate, vinyl stearate, vinyl oleate, and vinyl benzoate, and these can be used alone or in combination of two or more. Vinyl acetate is preferred.

[0134] Examples of polymerizable compounds copolymerizable with vinyl esters include ethylene, propene, 1-butene, isobutylene, 1,3-butadiene, isopropenyl acetate, 2-propenyl acetate, 3,4-diacetoxy-1-butene, 2,2-dialkyl-4-vinyl-1,3-dioxolanes such as 2,2-dimethyl-4-vinyl-1,3-dioxolane, 3,4-dihydroxy-1-butene, 3,4-diacyloxy-1-butene, 3-acyloxy-4-hydroxy-1-butene, 4-acyloxy-3-hydroxy-1-butene, 3,4-diacyloxy-2-methyl-1-butene, 4,5-dihydroxy-1-pentene, 4,5-diacyloxy-1-pentene, 4,5 3,4-diacyloxy-1-butenes such as 5,6-dihydroxy-1-hexene and 5,6-diacyloxy-1-hexene, styrene, α-methylstyrene, vinyl chloride, acrylonitrile, maleic anhydride, methyl acrylate, methyl methacrylate, N-vinyl-N-methylformamide, vinylacetamide, N-vinylformamide, N-(hydroxymethyl)-N-vinylformamide, hydroxyethyl acrylate, methyl vinyl ketone, and diacetone acrylamide, and these may be used alone or in combination of two or more. Among these, it is preferable to use at least one selected from ethylene, propene, isopropenyl acetate, 2-propenyl acetate, 3,4-diacetoxy-1-butene, and 2,2-dialkyl-4-vinyl-1,3-dioxolane.

[0135] When a vinyl ester and a polymerizable compound are used in combination, the amounts used can be adjusted as appropriate. For example, the amount of the polymerizable compound blended is 1 mol % to 40 mol %, as another example, 1 mol % to 20 mol %, and as another example, 1 mol % to 15 mol %, of the total amount of the vinyl ester and the polymerizable compound.

[0136] The first vinyl alcohol polymer may be acetalized. Examples of the aldehyde used for acetalization include aliphatic aldehydes such as formaldehyde, acetaldehyde, propylaldehyde, butylaldehyde, octylaldehyde, and dodecylaldehyde; alicyclic aldehydes such as cyclohexanecarbaldehyde; aromatic aldehydes such as benzaldehyde, naphthaldehyde, anthraldehyde, phenylacetaldehyde, tolualdehyde, dimethylbenzaldehyde, cuminaldehyde, and benzylaldehyde; cyclohexene aldehyde, dimethylcyclohexene aldehyde, acrylonitrile, and the like; Examples of the aldehyde include unsaturated aldehydes such as chlorine; aldehydes having a heterocycle such as furfural and 5-methylfurfural; hemiacetals such as glucose and glucosamine; and aldehydes having an amino group such as 4-aminobutyraldehyde. In addition, aliphatic ketones such as 2-propanone, methyl ethyl ketone, 3-pentanone, and 2-hexanone; alicyclic ketones such as cyclopentanone and cyclohexanone; and aromatic ketones such as acetophenone and benzophenone can be used alone or in combination of two or more.

[0137] As the acid catalyst used in the acetalization, conventionally known organic or inorganic acids such as acetic acid, paratoluenesulfonic acid, nitric acid, sulfuric acid, and hydrochloric acid can be used.

[0138] The weight average molecular weight of the vinyl alcohol polymer is, for example, 3,000 to 500,000, more preferably 5,000 to 100,000, and even more preferably 10,000 to 80,000.

[0139] In the present invention, the first vinyl alcohol polymer is one that is soluble in a 1:1 (mass ratio) solution of water and ethanol at 25° C. to a concentration of 5% by mass or more, and in which a solution of the vinyl alcohol polymer dissolved in the 1:1 (mass ratio) solution of water and ethanol at 5% by mass has a viscosity of 200 mPa s or less at 25° C. If the vinyl alcohol polymer is dissolved in the 1:1 (mass ratio) solution of water and ethanol and left to stand at 25° C. for one day, and no precipitate or gel-like substance is found, the vinyl alcohol polymer is determined to be dissolved.

[0140] While vinyl alcohol-based polymers have excellent solubility in water, many have low solubility in low-molecular-weight alcohols such as ethanol, and such vinyl alcohol-based polymers are only slightly soluble in a cosolvent of water and ethanol. In the present invention, a polymer with excellent solubility in a cosolvent of water and ethanol is selected and used. This allows the coating agent used to form the first resin layer to have excellent coatability even at high solids contents, enabling the efficient formation of a coating film of an appropriate thickness for the first resin layer. Furthermore, less energy is required to volatilize the solvent from the coating agent during the formation of the first resin layer, thereby reducing the environmental impact. The solubility of a vinyl alcohol-based polymer in low-molecular-weight alcohols can be adjusted, for example, by incorporating a skeleton that increases solubility in alcohol into the main chain by using ethylene or propylene with a vinyl ester, or by using 3,4-diacetoxy-1-butene with a vinyl ester to introduce hydroxyl groups into the side chain, or by adjusting the molecular weight, butyralization, and saponification degree of the vinyl alcohol-based polymer. The saponification degree of the vinyl alcohol-based polymer can be adjusted as appropriate, but is, for example, 90% or higher.

[0141] The first polyalkyleneimine is a resin having a polyalkyleneimine skeleton, and is obtained by polymerizing one or more alkyleneimines (for example, ethyleneimine, propyleneimine) by a conventional method.

[0142] The first polyalkyleneimine may be a linear polyalkyleneimine having a linear polyalkyleneimine chain, or a branched polyalkyleneimine having a branched polyalkyleneimine chain. Examples of polyalkyleneimines include polyethyleneimine and polypropyleneimine. The polyalkyleneimine may have a substituent (e.g., a hydroxypropyl group or a hydroxyethyl group) introduced into at least some of the nitrogen atoms of the polyalkyleneimine chain. Polyalkyleneimines modified with organometallic compounds such as tetraisopropyl titanate, tetra-normal-butyl titanate, butyl titanate dimer, tetra(2-ethylhexyl) titanate, tetramethyl titanate, polyhydroxytitanium stearate, titanium bisacetylacetonate, titanium tetraacetylacetonate, polytitanium acetylacetonate, titanium octylene glycolate, titanium ethylacetoacetate, titanium lactate, titanium triethanolamine, and titanium stearate may also be used, and two or more polyalkyleneimines may also be used in combination.

[0143] The first polyalkyleneimine has an amino group (NHR group, NH ２ It is believed that the ethylene group and the ethylene group contribute to improving the adhesion between the vinyl alcohol polymer and the olefin film, and since this is effective in improving the adhesion, it is preferable that the polyalkyleneimine contains a branched polyalkyleneimine.

[0144] The number average molecular weight of the first polyalkyleneimine is, for example, from 5,000 to 100,000. The number average molecular weight of the polyalkyleneimine is measured by GPC (gel permeation chromatography) using pullulan as a standard substance.

[0145] From the viewpoint of the balance between the adhesive strength of the laminate and the suppression of blocking when the first resin layer is wound up after being formed, it is preferable that the amount of the first polyalkylimine in the first resin layer be 1 mass % or more and 25 mass % or less of the total amount of the first vinyl alcohol-based polymer and the first polyalkylimine.

[0146] The first resin layer may contain a resin other than the first vinyl alcohol polymer and the first polyalkylimine. Examples of such resins include cellulose resins, polyesters, polyurethanes, vinyl resins such as homopolymers or copolymers of olefins or styrenes, acrylic resins, epoxy resins, amide resins, natural rubber, and composites thereof (e.g., core-shell resins). The content of these resins is preferably kept to 10% by mass or less of the total amount of the first vinyl alcohol polymer and the first polyalkyleneimine. More preferably, it is 5% by mass or less, and even 1% by mass or less. It may even be 0% by mass.

[0147] The first resin layer has a glass transition temperature of 40°C or higher and 80°C or lower. This prevents blocking when the substrate is wound up after the first resin layer is formed, and allows for a laminate with excellent adhesive strength and recyclability. The glass transition temperature of the first resin layer can be adjusted by the first vinyl alcohol polymer and first polyalkyleneimine used, their compounding ratios, etc. The glass transition temperature of the first resin layer is more preferably 50°C or higher and more preferably 70°C or lower.

[0148] The first resin layer is formed, for example, by applying a coating agent containing a first vinyl alcohol polymer, a first polyalkyleneimine, and an aqueous solvent onto the first substrate, and then drying the solvent.

[0149] The aqueous solvent may be water, a water-soluble organic solvent that dissolves in water, or the like. As the water, pure water or ultrapure water such as ion-exchanged water, ultrafiltered water, reverse osmosis water, or distilled water may be used. From the viewpoint of long-term storage, it is preferable to use water that has been sterilized by ultraviolet irradiation or the addition of hydrogen peroxide, for example, in order to prevent the growth of mold or bacteria.

[0150] Examples of water-soluble organic solvents include glycols such as ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, propylene glycol, polyethylene glycol, and polypropylene glycol; diols such as butanediol, pentanediol, and hexanediol; glycol esters such as propylene glycol laurate; diethylene glycol ethers such as diethylene glycol monoethyl, diethylene glycol monobutyl, diethylene glycol monohexyl, and carbitol; glycol ethers such as cellosolves containing propylene glycol ether, dipropylene glycol ether, and triethylene glycol ether; alcohols such as methanol, ethanol, isopropyl alcohol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, butyl alcohol, and pentyl alcohol; lactones such as sulfolane, esters, ketones, and γ-butyrolactone; lactams such as N-(2-hydroxyethyl)pyrrolidone; and various other solvents known as aqueous organic solvents, such as glycerin and its polyalkylene oxide adducts. These aqueous organic solvents can be used alone or in combination of two or more.

[0151] The coating agent used to form the first resin layer may further contain additives, such as a crosslinking agent capable of reacting with a functional group possessed by the first vinyl alcohol polymer or the first polyalkylimine, an inorganic filler, an antifoaming agent, a leveling agent, a stabilizer (such as an antioxidant, a heat stabilizer, or an ultraviolet absorber), a plasticizer, an antistatic agent, a lubricant, an antiblocking agent, a colorant, or a leveling agent.

[0152] Examples of crosslinking agents include aldehydes such as formalin and glutaraldehyde; acetals such as diacetalized products of glutaraldehyde; aliphatic polyisocyanates such as hexamethylene diisocyanate and its derivatives (adduct, nurate, biuret, etc.), aromatic aliphatic polyisocyanates such as xylylene diisocyanate and its derivatives, aromatic polyisocyanates such as toluene diisocyanate and its derivatives, and isocyanates such as urethane prepolymers which are reaction products of these isocyanates with polyols; epoxies; titanium, silicon, aluminum, zirconium, Examples of the isocyanate include organometallic compounds of boron or the like with alkoxides or the like; methylol ureas such as methylol urea and methylol melamine; carboxyl group-containing polymers such as polyacrylic acid polymers and maleic anhydride polymers; carbodiimides such as p-phenylene-bis(2,6-xylylcarbodiimide), tetramethylene-bis(t-butylcarbodiimide), and cyclohexane-1,4-bis(methylene-t-butylcarbodiimide); boric acid; and titanium lactate. As the isocyanate, a blocked isocyanate using a known blocking agent or an emulsion-type isocyanate may be used.

[0153] The use of a crosslinking agent is expected to improve adhesion to an olefin-based substrate. The amount of the crosslinking agent is, for example, 5 parts by mass or more and 50 parts by mass or less per 100 parts by mass of the total amount of the first vinyl alcohol-based polymer and the first polyalkyleneimine.

[0154] The resin content of the coating agent, including the first vinyl alcohol polymer and the first polyalkyleneimine, can be appropriately adjusted, but is, for example, 7.5 mass% or more. The solid content of the coating agent is not particularly limited, but is adjusted so that the viscosity at 25°C does not exceed 300 mPa s.

[0155] The method for applying the coating agent is not particularly limited, and examples that can be used include spraying, spin coating, dipping, roll coating, blade coating, doctor roll coating, doctor blade coating, curtain coating, slit coating, screen printing, inkjet printing, dispensing, die coating, direct gravure, reverse gravure, flexography, knife coating, and dot coating.

[0156] The film thickness of the first resin layer can be adjusted as appropriate, but is, for example, 0.1 μm or more and 2.0 μm or less.

[0157] (Printed Layer) The laminate of the present invention may include layers other than the first substrate, the second substrate, the adhesive layer, and the first resin layer. An example of such a layer is a printed layer. The printed layer is a layer on which characters, figures, symbols, or other desired designs are printed using printing ink between the first substrate and the adhesive layer, or on the surface of the first substrate opposite the adhesive layer. When the printed layer is disposed between the first substrate and the adhesive layer, it is preferable that the printed layer be disposed between the first resin layer and the adhesive layer. This allows the printed layer to be easily removed along with the peeling of the adhesive, resulting in a recycled plastic with a higher purity, as described below.

[0158] The printing method and printing ink are not particularly limited, and known printing methods and printing inks can be used. Printing inks using methods such as gravure printing, flexographic printing, lithographic offset printing, and inkjet recording printing are often used for the films used as the substrate. Printing inks that combine these printing methods with methods of curing using active energy rays such as ultraviolet (UV), LED, and electron beam (EB), or methods of curing using heat, are also used. Depending on the solvent used, inks may be referred to as aqueous inks or organic solvent-based inks.

[0159] Specific examples include gravure printing ink, flexographic printing ink (in some industries, gravure printing ink and flexographic printing ink are sometimes called liquid ink), ultraviolet-curable ink for lithographic offset printing, electron beam-curable ink for lithographic offset printing, ultraviolet-curable ink for inkjet recording and printing, electron beam-curable ink for inkjet recording and printing, etc. Biomass inks made from biomass raw materials are also used as appropriate.

[0160] The printing ink may contain a resin, a colorant, and a solvent as essential components, or may be a so-called clear ink that contains a resin and a solvent but does not substantially contain a colorant. The printing layer may be provided on the entire surface of the first substrate, or may be provided only on a part of the surface.

[0161] Taking the case where the printing ink is gravure printing ink or flexographic printing ink as an example, the resin used in the printing ink is not particularly limited and includes, for example, acrylic resin, polyester resin, styrene resin, styrene-maleic acid resin, maleic acid resin, polyamide resin, polyurethane resin, vinyl chloride-vinyl acetate copolymer resin, vinyl chloride-acrylic copolymer resin, ethylene-vinyl acetate copolymer resin, vinyl acetate resin, polyvinyl chloride resin, chlorinated polypropylene resin, cellulose-based resin, epoxy resin, alkyd resin, rosin-based resin, rosin-modified maleic acid resin, ketone resin, cyclized rubber, chlorinated rubber, butyral, petroleum resin, etc., and one or more of these can be used in combination. Preferably, at least one or two or more selected from polyurethane resin, vinyl chloride-vinyl acetate copolymer resin, and cellulose-based resin are used.

[0162] Colorants used in printing inks include inorganic pigments such as titanium oxide, red iron oxide, antimony red, cadmium red, cadmium yellow, cobalt blue, Prussian blue, ultramarine, carbon black, and graphite; organic pigments such as soluble azo pigments, insoluble azo pigments, azo lake pigments, condensed azo pigments, copper phthalocyanine pigments, and condensed polycyclic pigments; and extender pigments such as calcium carbonate, kaolin clay, barium sulfate, aluminum hydroxide, and talc.

[0163] The organic solvent used in the printing ink preferably does not contain an aromatic hydrocarbon organic solvent. More specific examples include alcohol organic solvents such as methanol, ethanol, n-propanol, isopropanol, and butanol, ketone organic solvents such as acetone, methyl ethyl ketone, and methyl isobutyl ketone, ester organic solvents such as methyl acetate, ethyl acetate, propyl acetate, and butyl acetate, aliphatic hydrocarbon organic solvents such as n-hexane, n-heptane, and n-octane, and alicyclic hydrocarbon organic solvents such as cyclohexane, methylcyclohexane, ethylcyclohexane, cycloheptane, and cyclooctane, and these can be used alone or in combination of two or more.

[0164] In consideration of the establishment of a recycling-oriented society that should continue to develop (sustainability), it is also preferable that the liquid printing ink used in the present invention is a gravure printing ink or a flexographic printing ink that uses plant-derived raw materials.

[0165] Examples of plant-derived raw materials include cellulose resins such as cellulose acetate propionate resin and nitrocellulose; polyamide resins using dimer acids or polymerized fatty acids derived from natural oils such as soybean oil, palm oil, and rice bran oil; biomass polyurethanes synthesized from plant-derived raw materials such as polycarboxylic acids such as succinic acid, succinic anhydride, adipic acid, azelaic acid, sebacic acid, dimer acid, glutaric acid, and malic acid; polyols such as ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, neopentyl glycol, pentylene glycol, 1,10-dodecanediol, dimer diol, and isosorbide; and polyisocyanates such as 1,5-pentamethylene diisocyanate and dimer diisocyanate; and rosin resins.

[0166] As the biomass gravure printing ink or flexographic printing ink, commercially available products listed by the Japan Organics Recycling Association can also be used.

[0167] (Second Resin Layer) The laminate of the present invention comprises a first substrate, a second substrate, an adhesive layer, and a first resin layer. In addition, a second resin layer containing a second vinyl alcohol polymer and a second polyalkyleneimine and having a glass transition temperature of 40 ° C. or more and 80 ° C. or less may be included between the second substrate and the adhesive layer. When a second resin layer is provided in addition to the first resin layer, the second resin layer and the second substrate are easily peeled off in the detachment step described below. In addition, the layers sandwiched between the first resin layer and the second resin layer, such as the printing layer and the adhesive layer, are not too finely divided after being peeled off from the first substrate and the second substrate, and can be easily recovered. In other words, this is preferable because it can be made into a laminate with better recyclability.

[0168] The second vinyl alcohol polymer can be the same as that described for the first vinyl alcohol polymer (that is, soluble in a 1:1 (mass ratio) solution of water and ethanol at 25°C at a concentration of 5% by mass or more, and the viscosity of a 5% by mass solution of the vinyl alcohol polymer in a 1:1 (mass ratio) solution of water and ethanol at 25°C is 200 mPa s or less). The second vinyl alcohol polymer can be the same as or different from the first vinyl alcohol polymer. The second polyalkyleneimine can be the same as or different from the first polyalkyleneimine. The second polyalkyleneimine can be the same as or different from the first polyalkyleneimine.

[0169] The second resin layer can be formed by the same method as the first resin layer. The coating agent used to form the second resin layer may be the same as that used to form the first resin layer, or may be different from that used to form the first resin layer, for example, in the contents of the second vinyl alcohol polymer and the second polyalkyleneimine, the solvent used, the amount of coating agent applied, etc.

[0170] The glass transition temperature of the second resin layer is more preferably 50° C. or higher, and more preferably 70° C. or lower. In the second resin layer, the amount of the second polyalkylimine is preferably 1% by mass or higher and 25% by mass or lower of the total amount of the second vinyl alcohol polymer and the second polyalkylimine. The film thickness of the second resin layer can be adjusted as appropriate, and is, for example, 0.1 μm or higher and 2.0 μm or lower.

[0171] (Third substrate, third resin layer, fourth resin layer) The laminate of the present invention may include a third substrate in addition to the first substrate and the second substrate. The third substrate can be the same as the first substrate. In one embodiment of the present invention, the second substrate is a film (sealant film) having heat sealability that can be melted by heat and fused to each other, and the first substrate and the third substrate are substrates that are not expected to function as sealant films. In another embodiment of the present invention, the first substrate, the second substrate, and the third substrate are all substrates that are not expected to function as sealant films.

[0172] When the laminate of the present invention includes a third substrate, the third substrate is disposed between the first substrate and the second substrate, and the first substrate and the third substrate, and the third substrate and the second substrate are bonded together directly or via the first resin layer or other layers provided as necessary, using the same adhesive as described above. The adhesive layer disposed between the first substrate and the third substrate and the adhesive layer disposed between the third substrate and the second substrate may be formed of the same adhesive or may be formed of different adhesives.

[0173] A resin layer similar to the first resin layer (hereinafter also referred to as a third resin layer) may be provided between the third substrate and the adhesive layer on the surface of the third substrate facing the first substrate. A resin layer similar to the first resin layer (hereinafter also referred to as a fourth resin layer) may be provided between the third substrate and the adhesive layer on the surface of the third substrate facing the second substrate.

[0174] The third and fourth resin layers each contain a vinyl alcohol-based polymer (which is soluble in a 1:1 (mass ratio) solution of water and ethanol at 25°C at a concentration of 5% by mass or more, and in which a 5% by mass solution of the vinyl alcohol-based polymer in a 1:1 (mass ratio) solution of water and ethanol has a viscosity of 200 mPa s or less at 25°C) similar to those exemplified as components of the first resin layer, and a polyalkyleneimine, and have a glass transition temperature of 40°C or higher and 80°C or lower.

[0175] When a third resin layer and a fourth resin layer are provided in addition to the first resin layer and the second resin layer, the first substrate, the second substrate, and the third substrate are easily peeled off in the detachment step described below, and the layer sandwiched between the first resin layer and the third resin layer, for example, the printing layer and the adhesive layer, or the layer sandwiched between the second resin layer and the fourth resin layer, for example, the adhesive layer, is not too finely divided after being peeled off from the substrate and can be easily recovered. That is, it is preferable because it can be made into a laminate with better recyclability.

[0176] The vinyl alcohol polymers used in the third resin layer and the fourth resin layer may be the same as or different from the first vinyl alcohol polymer and the second vinyl alcohol polymer, respectively. The polyalkyleneimines used in the third resin layer and the fourth resin layer may be the same as or different from the first polyalkyleneimine and the second polyalkyleneimine, respectively.

[0177] The third resin layer and the fourth resin layer can be provided by the same method as the first resin layer. The coating agent used to form the third resin layer and the fourth resin layer may be the same as that used to form the first resin layer, or may be different from that used to form the first resin layer, for example, in the vinyl alcohol polymer and the second polyalkyleneimine content, the solvent used, the coating amount of the coating agent, etc.

[0178] The glass transition temperatures of the third resin layer and the fourth resin layer are more preferably 50° C. or higher, and more preferably 70° C. or lower. In the third resin layer and the fourth resin layer, the blending amount of polyalkylimine is preferably 1% by mass or higher and 25% by mass or lower of the total amount of the vinyl alcohol polymer and the polyalkylimine. The film thicknesses of the third resin layer and the fourth resin layer can be adjusted as appropriate, and are, for example, 0.1 μm or higher and 2.0 μm or lower.

[0179] (Barrier Coat Layer) The laminate of the present invention may include layers other than those described above. An example of such a layer is a barrier coat layer. The barrier coat layer is a layer that prevents the permeation of oxygen and water vapor, and can be provided at any position of the laminate of the present invention by applying and drying a barrier coating agent.

[0180] An example of the barrier coating agent is a barrier coating agent (1) containing a vinyl alcohol polymer and an aqueous solvent.

[0181] Specific examples of vinyl alcohol polymers include polyvinyl alcohol, ethylene vinyl alcohol, polyvinyl butyral, etc. The vinyl alcohol polymer may have a reactive functional group other than a hydroxyl group, such as an acetoacetyl group, a carboxyl group, an anionic carboxyl group, a sulfonic acid group, or an anionic sulfonic acid group. These may be used alone or in combination of two or more.

[0182] The aqueous solvent may be water or the same water-soluble organic solvents as those exemplified as those usable for preparing the coating agent used to form the first resin layer. The aqueous solvents may be used alone or in combination of two or more.

[0183] The barrier coating agent (1) may further contain additives such as a layered inorganic compound, a crosslinking agent capable of reacting with a functional group possessed by the vinyl alcohol polymer, an adhesion improver, an inorganic filler, an antifoaming agent, a stabilizer (antioxidant, heat stabilizer, ultraviolet absorber, etc.), a plasticizer, an antistatic agent, a lubricant, an antiblocking agent, a colorant, and a leveling agent.

[0184] Commercially available barrier coating agents (1) can also be used, and examples thereof include EXEVIA (registered trademark) manufactured by Sumitomo Chemical Co., Ltd., SunBar (registered trademark) series manufactured by Sun Chemical Co., Ltd., Takelac WPB (registered trademark) series manufactured by Mitsui Chemicals, Inc., and LG-OX manufactured by Tokyo Ink Co., Ltd.

[0185] The barrier coating agent is a water-soluble polymer having a hydroxyl group and Si(OR １ ) ４ , or R ２ Si(OR ３ ) ３ (However, OR １ and OR ３ represents a hydrolyzable group, R ２ represents an organic functional group), or one or more hydrolyzates of the silicon compounds.

[0186] Examples of water-soluble polymers having a hydroxyl group include vinyl alcohol polymers, polyvinylpyrrolidone, starch, methyl cellulose, carboxymethyl cellulose, and sodium alginate.

[0187] Examples of silicon compounds or hydrolyzates of silicon compounds include tetraethyl silicate (Si(OC ２ H ５ ) ４ ) (hereinafter sometimes referred to as TEOS), tetraalkoxysilanes such as tetramethyl silicate; trialkoxysilanes such as trimethoxymethylsilane, triethoxymethylsilane, trimethoxyvinylsilane; dialkoxysilanes such as dimethoxydimethylsilane, diethoxydimethylsilane; monoalkoxysilanes such as methoxytrimethylsilane, ethoxytrimethylsilane, or hydrolysates or partial hydrolysates thereof.

[0188] TEOS is preferred because it is relatively stable in an aqueous solvent after hydrolysis. ２ Si(OR ３ ) ３ Contains R ２is preferably a vinyl group, an epoxy group, an acryloyl group, a methacryloxy group, a ureido group, or an isocyanate group.

[0189] The barrier coating agent (2) may contain components other than those described above. Such components include other water-soluble polymers (e.g., sodium polyacrylate, polyethylene oxide, polyvinylpyrrolidone, dextrin, chitosan, chitin, methylcellulose, hydroxyethyl cellulose, etc.), fragrances, rust inhibitors, colorants, extenders, antifoaming agents, ultraviolet absorbers, fluorescent brighteners, liquid paraffins, bitter components (e.g., denatonium benzoate, etc.), etc. The barrier coating agent (2) can use the same aqueous solvent as the gas barrier coating agent (1).

[0190] An example of the barrier coating agent is a barrier coating agent (3) containing a polyester polyol, which is a reaction product of an acid component essentially containing an ortho-orienting polycarboxylic acid or a meta-orienting polycarboxylic acid with a polyol component, and an isocyanate compound.

[0191] Examples of ortho-orienting polycarboxylic acids include orthophthalic acid or its anhydride, naphthalene 2,3-dicarboxylic acid or its anhydride, naphthalene 1,2-dicarboxylic acid or its anhydride, anthraquinone 2,3-dicarboxylic acid or its anhydride, and 2,3-anthracenecarboxylic acid or its anhydride. These compounds may have a substituent on any carbon atom of the aromatic ring. Examples of the substituent include a chloro group, a bromo group, a methyl group, an ethyl group, an i-propyl group, a hydroxyl group, a methoxy group, an ethoxy group, a phenoxy group, a methylthio group, a phenylthio group, a cyano group, a nitro group, an amino group, a phthalimido group, a carboxyl group, a carbamoyl group, an N-ethylcarbamoyl group, a phenyl group, and a naphthyl group.

[0192] Examples of meta-oriented polycarboxylic acids include isophthalic acid, 1,3-naphthalenedicarboxylic acid, etc. These compounds may have the same substituents as those exemplified in the description of ortho-oriented polycarboxylic acids on any carbon atom of the aromatic ring.

[0193] The polycarboxylic acid used in the synthesis of the polyester polyol may contain a polycarboxylic acid other than an ortho-oriented polycarboxylic acid or a meta-oriented polycarboxylic acid. Examples of such a polycarboxylic acid include aliphatic polycarboxylic acids such as succinic acid, adipic acid, azelaic acid, sebacic acid, and dodecanedicarboxylic acid; unsaturated bond-containing polycarboxylic acids such as maleic anhydride, maleic acid, and fumaric acid; alicyclic polycarboxylic acids such as 1,3-cyclopentanedicarboxylic acid and 1,4-cyclohexanedicarboxylic acid; terephthalic acid, pyromellitic acid, trimellitic acid, 1,4-naphthalenedicarboxylic acid, 1,5-anthracenedicarboxylic acid, 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, naphthalic acid, and 1,4-anthracenedicarboxylic acid. Examples of aromatic polycarboxylic acids include helical dicarboxylic acids, 2,6-anthracene dicarboxylic acid, 2,7-anthracene dicarboxylic acid, 1,8-anthracene dicarboxylic acid, 9,10-anthracene dicarboxylic acid, biphenyl dicarboxylic acid, 1,2-bis(phenoxy)ethane-p,p'-dicarboxylic acid, and acid anhydrides or ester-forming derivatives of these dicarboxylic acids, p-hydroxybenzoic acid, p-(2-hydroxyethoxy)benzoic acid, and ester-forming derivatives of these dihydroxycarboxylic acids, and these can be used alone or in combination of two or more. Among these, succinic acid, 1,3-cyclopentane dicarboxylic acid, and acid anhydrides thereof are preferred.

[0194] When the polycarboxylic acid contains a polycarboxylic acid other than an ortho-oriented polycarboxylic acid or a meta-oriented polycarboxylic acid, the proportion of the ortho-oriented polycarboxylic acid or the meta-oriented polycarboxylic acid in the total amount of the polycarboxylic acid is preferably 40 to 100 mass%.

[0195] The polyhydric alcohol used in the synthesis of polyester polyol preferably contains a dihydric alcohol such as ethylene glycol, propylene glycol, butylene glycol, neopentyl glycol, or cyclohexanedimethanol, or a trihydric alcohol such as glycerol, trimethylolethane, or trimethylolpropane. Among these, it is more preferable to contain ethylene glycol or glycerol. It is particularly preferable to contain glycerol. The polyhydric alcohol preferably contains 10 to 100% by mass of glycerol.

[0196] Polyhydric alcohols other than those mentioned above may be used in combination, and examples thereof include aliphatic diols such as 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, methylpentanediol, dimethylbutanediol, butylethylpropanediol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, and tripropylene glycol; trihydric or higher polyhydric alcohols such as glycerin, trimethylolpropane, trimethylolethane, tris(2-hydroxyethyl)isocyanurate, 1,2,4-butanetriol, pentaerythritol, and dipentaerythritol; hydroquinone, resorcinol, catechol, naphthalenediol, biphenol, bisphenol A, bisphenol F, and tetramethylbiphenol; ethylene oxide-extended products thereof; and aromatic polyhydric phenols such as hydrogenated alicyclic alcohols.

[0197] When the polyester polyol has three or more hydroxyl groups, some of the hydroxyl groups may be modified with a polycarboxylic acid or its acid anhydride. The proportion of hydroxyl groups modified with the polycarboxylic acid is preferably ⅓ or less of the hydroxyl groups of the polyester polyol. Examples of polycarboxylic acids used for modification include, but are not limited to, succinic anhydride, maleic acid, fumaric acid, 1,2-cyclohexanedicarboxylic anhydride, 4-cyclohexene-1,2-dicarboxylic anhydride, 5-norbornene-2,3-dicarboxylic anhydride, phthalic anhydride, 2,3-naphthalenedicarboxylic anhydride, trimellitic anhydride, oleic acid, and sorbic acid.

[0198] The polyester polyol may be a polyester polyurethane polyol having a number average molecular weight of 1,000 to 15,000 obtained by urethane elongation through a reaction with a diisocyanate compound. The urethane-elongated polyester polyol contains components with molecular weights equal to or greater than a certain level and urethane bonds, and therefore has excellent gas barrier properties and initial cohesive strength.

[0199] The isocyanate compound used in the barrier coating agent (3) may be the same as the polyisocyanate compound used in the adhesive (1), and is preferably one having an aromatic ring or an aliphatic ring. Examples of isocyanate compounds having an aromatic ring or an aliphatic ring include toluene diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, isophorone diisocyanate, or trimers of these isocyanate compounds, and adducts obtained by reacting an excess amount of these isocyanate compounds with low-molecular-weight active hydrogen compounds such as ethylene glycol, propylene glycol, meta-xylylene alcohol, 1,3-bishydroxyethylbenzene, 1,4-bishydroxyethylbenzene, trimethylolpropane, glycerol, pentaerythritol, erythritol, sorbitol, ethylenediamine, monoethanolamine, diethanolamine, triethanolamine, and meta-xylylenediamine, and alkylene oxide adducts thereof, various polyester resins, polyether polyols, and high-molecular-weight active hydrogen compounds such as polyamides. The isocyanate compounds may be used alone or in combination.

[0200] It is also preferable to use a compound having an active hydrogen group in combination with the barrier coating agent (3). Examples of the active hydrogen group in the compound having active hydrogen include a hydroxyl group, an amino group, an imino group, a carboxylic acid, a urea group, and an SH group. Among these, a hydroxyl group, an amino group, and an SH group are preferred.

[0201] When the solubility parameter of the compound having active hydrogen is 29.5 or less, the compatibility between the polyester polyol and the isocyanate compound is improved, the compound having active hydrogen is uniformly present in the barrier coat layer, and the effect of improving gas barrier properties can be expected. Note that in this specification, the solubility parameter refers to the δT value listed in the Hansen Solubility Parameter Calculation Software (HSPiP) or the δT value calculated using the SMILES notation.

[0202] Examples of compounds having a hydroxyl group as an active hydrogen group include alkanols such as octanol and decanol, aliphatic diols such as 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, 2,2,2-trimethylpentanediol, 3,3-dimethylolheptane, octanediol, and decanediol, alicyclic alcohols such as 1,3- or 1,4-cyclohexanedimethanol and 1,3- or 1,4-cyclohexanediol, aromatic alcohols such as salicylic alcohol and vanillyl alcohol, hydrogenated bisphenol A, 1,4-dihydroxy-2-butene, 2,6- Examples of the alcohol include dihydric alcohols such as dimethyl-1-octene-3,8-diol, bisphenol A, diethylene glycol, triethylene glycol, and dipropylene glycol; trihydric alcohols such as glycerin, trimethylolpropane, and triisopropanolamine; tetrahydric alcohols such as tetramethylolmethane (pentaerythritol) and diglycerin; pentahydric alcohols such as xylitol; hexahydric alcohols such as sorbitol, mannitol, allitol, iditol, dulcitol, altritol, inositol, and dipentaerythritol; and heptahydric alcohols such as perseitol.

[0203] Examples of compounds having an amino group as an active hydrogen group include aliphatic amines such as octylamine, decaneamine, 1,8-diaminooctane, and 1,10-diaminodecane; alicyclic amines such as isophoronediamine, norbornenediamine, bis(aminomethyl)cyclohexane, cyclohexanediamine, diaminodicyclohexylmethane, and methylenebis(methylcyclohexaneamine); and aromatic amines such as 1-xylylenediamine, N-benzylethylenediamine, phenylenediamine, diaminodiphenylmethane, diaminodiphenyl ether, 1,3-bis(3-aminophenoxy)benzene, toluenediamine, and diethyltoluenediamine.

[0204] Examples of compounds having an SH group as an active hydrogen group include hexyl mercaptan, heptyl mercaptan, octyl mercaptan, nonyl mercaptan, decyl mercaptan, undecyl mercaptan, and dodecyl mercaptan. , tridecyl mercaptan, tetradecyl mercaptan, pentadecyl mercaptan, mercaptophenol, mercaptopropionic acid, mercaptobutyric acid, 1,4-butanedithiol, 2-mercaptobenzothiazole, 3-mercapto-1,2-propanediol, mercaptomethylbutanol, 3-mercapto-2-methylpentanol, 3-mercapto-3-methylbutanol, 4-ethoxy-2-methyl-2-butanethiol, hexanethiol, dimethylthiophenol, 1,4-bis(3-mercaptobutyryloxy)butane, trimethylolpropane tris(3-mercaptobutyrate), pentaerythritol tetrakis(3-mercaptobutyrate), and the like.

[0205] The compound having active hydrogen may be used alone or in combination of two or more kinds. Isosorbide, tris(2-hydroxyethyl) isocyanurate, trimethylolpropane, dipentaerythritol, and 1,4-cyclohexanedimethanol are preferred.

[0206] The amount of the compound having active hydrogen is preferably 0.5% by mass or more and 20% by mass or less based on the solid content of the barrier coating agent (3).

[0207] The barrier coating agent (3) may further contain a layered inorganic compound, an acid anhydride, an oxygen scavenger, an inorganic filler, and when an inorganic material is used, a dispersant, a stabilizer (antioxidant, heat stabilizer, ultraviolet absorber, etc.), a plasticizer, an antistatic agent, a lubricant, an antiblocking agent, a colorant, a leveling agent, a slip improver, etc.

[0208] The barrier coating agent (3) may be diluted with an organic solvent, such as ester solvents like ethyl acetate, propyl acetate, and butyl acetate, ketone solvents like acetone and 2-butanone, ether solvents like tetrahydrofuran, aliphatic solvents like hexane and cyclohexane, and aromatic solvents like toluene.

[0209] (Heat-resistant coating layer) The laminate of the present invention may include layers other than those described above. An example of such a layer is a heat-resistant coating layer. The heat-resistant coating layer is a layer having a function of improving the heat resistance of the laminate of the present invention, and can be provided at any position on the laminate of the present invention by applying and drying a heat-resistant coating agent.

[0210] Taking the case where the laminate of the present invention is used as a component of a packaging material for packaging contents as an example, if a bag is made and filled with contents, and the outermost substrate is a film with low heat resistance such as a polyethylene film or a polypropylene film, there is a risk that the laminate will shrink due to heat when the bag is made by heat sealing. Such a problem can be prevented by providing a heat-resistant coating layer.

[0211] The heat-resistant coating layer is preferably disposed outside the substrate that is positioned outermost from the contents when the bag is made from the substrates constituting the laminate. For example, when the first substrate is the outermost substrate among the substrates constituting the laminate of the present invention and the printed layer is disposed between the first substrate and the adhesive layer, the heat-resistant coating layer is preferably disposed on the surface of the first substrate opposite the adhesive layer. Alternatively, when the first substrate is the outermost substrate among the substrates constituting the laminate of the present invention and the printed layer is disposed on the surface of the first substrate opposite the adhesive layer, the heat-resistant coating layer may be disposed between the printed layer and the first substrate, or the printed layer may be disposed between the heat-resistant coating layer and the first substrate.

[0212] Examples of heat-resistant coating agents include coating agents containing compounds having a cellulose skeleton, a benzene ring skeleton, an isocyanuric ring skeleton, or an alicyclic skeleton, whose homopolymer glass transition temperature (hereinafter sometimes referred to as Tg) is 100° C. or higher. Specific examples of such compounds include cellulose derivatives such as nitrocellulose, cellulose acetate, cellulose propionate, and cellulose butyrate; polyester resins having a benzene ring such as phthalic acid, naphthalenedicarboxylic acid, and an ethylene oxide (hereinafter sometimes referred to as EO) adduct of bisphenol A, and / or an alicyclic skeleton such as cyclopentanediol and dimethyloltricyclodecane; and urethane resins obtained by combining aromatic isocyanates such as diphenylmethane diisocyanate, toluene diisocyanate, xylene diisocyanate, and naphthalene diisocyanate; alicyclic isocyanates such as isophorone diisocyanate and norbornene diisocyanate; and / or isocyanuric triisocyanate with a polyol and / or tris(2-hydroxyethyl)isocyanurate. Polyisocyanates using the aforementioned isocyanates may also be used as curing agents. Furthermore, compounds having a benzene ring and an unsaturated double bond, such as styrene and phenoxydiethylene glycol acrylate, and / or compounds having an alicyclic structure and an unsaturated double bond, such as isobornyl acrylate and dicyclopentanyl acrylate, and radical copolymers such as (meth)acrylates are also preferably used. Furthermore, in consideration of adhesion to olefin films, a resin with a low Tg may be mixed and used.

[0213] The heat-resistant coating agent preferably uses inorganic fine particles such as alumina, magnesia, titania, zirconia, and silica (quartz, fumed silica, precipitated silica, silicic anhydride, fused silica, crystalline silica, and ultrafine amorphous silica) as aggregates because they have excellent heat resistance. Alternatively, boron nitride, aluminum nitride, alumina oxide, titanium oxide, magnesium oxide, zinc oxide, and silicon oxide are preferred because they have excellent thermal conductivity. The inorganic fine particles may be used alone or in combination.

[0214] The shape of the silica fine particles is not particularly limited, and spherical, hollow, porous, rod-like, plate-like, fibrous, or irregularly shaped particles can be used. For example, commercially available hollow silica fine particles such as Silinax manufactured by Nittetsu Mining Co., Ltd. can be used.

[0215] The primary particle diameter of the inorganic fine particles is preferably in the range of 5 nm to 200 nm, and more preferably 10 nm to 100 nm. The inorganic fine particles can be blended in a proportion of 5 to 90 wt % based on the total solid content of the heat-resistant coating agent and the inorganic fine particles, and the blending amount can be changed as needed depending on the purpose. In particular, a proportion of 20 mass % or more is preferred.

[0216] The heat-resistant coating agent may be colored. The colorant is not particularly limited, and examples thereof include inorganic pigments, organic pigments, and dyes used in general inks, paints, and recording agents, such as those used in the printing layer described below.

[0217] The heat-resistant coating agent may contain wax, silicon additives, or organic beads, such as amide wax, polypropylene wax, polyethylene wax, paraffin wax, carnauba wax, or rice wax, an ethylene oxide (EO) adduct of dimethylsiloxane, a silicon additive such as a silicon-modified product, or organic beads made of acrylic, nylon, urethane, or epoxy.

[0218] The solvent used in the heat-resistant coating agent is not particularly limited, but examples thereof include water, aromatic hydrocarbon organic solvents such as toluene, xylene, Solvesso #100, Solvesso #150, etc.; aliphatic hydrocarbon organic solvents such as hexane, methylcyclohexane, heptane, octane, decane, etc.; and various ester organic solvents such as methyl acetate, ethyl acetate, isopropyl acetate, normal propyl acetate, butyl acetate, amyl acetate, ethyl formate, butyl propionate, etc. Examples of water-miscible organic solvents include alcohols such as methanol, ethanol, propanol, butanol, and isopropyl alcohol; ketones such as acetone, methyl ethyl ketone, and cyclohexanone; and glycol ethers such as ethylene glycol (mono- and di-)methyl ether, ethylene glycol (mono- and di-)ethyl ether, ethylene glycol monopropyl ether, ethylene glycol monoisopropyl ether, monobutyl ether, diethylene glycol (mono- and di-)methyl ether, diethylene glycol (mono- and di-)ethyl ether, diethylene glycol monoisopropyl ether, diethylene glycol monobutyl ether, triethylene glycol (mono- and di-)methyl ether, propylene glycol (mono- and di-)methyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, and dipropylene glycol (mono- and di-)methyl ether. These can be used alone or in combination of two or more. Furthermore, to more effectively carry out coating, an antifoaming agent or a leveling agent can be used.

[0219] Commercially available heat-resistant coating agents can also be used, examples of which include SUNSYS FS241 manufactured by Sun Chemical Co., DH-004 / DH-HARDENER P-60 manufactured by DIC Corporation, and ThermaGloss 463 manufactured by Michelman.

[0220] <Packaging Material> The laminate of the present invention can be used as a multilayer packaging material for the purpose of protecting food, medicines, etc. When used as a multilayer packaging material, the layer structure can be changed depending on the contents, the environment of use, and the form of use.

[0221] The packaging material of the present invention can be obtained, for example, by overlapping the heat-sealable layers of the laminate of the present invention so that they face each other, and then heat-sealing the peripheral edges. Examples of bag-making methods include folding or overlapping the laminate of the present invention so that the inner layer surfaces (sealant film surfaces) face each other, and heat-sealing the peripheral edges using, for example, a side seal type, a two-sided seal type, a three-sided seal type, a four-sided seal type, an envelope seal type, a flared seal type, a flat-bottom seal type, a square-bottom seal type, a gusset seal type, or other heat seal type. The packaging material of the present invention can take various forms depending on the contents, usage environment, and usage form. Self-standing packaging materials (standing pouches) are also possible. Heat-sealing methods can be known, such as bar seal, rotary roll seal, belt seal, impulse seal, high-frequency seal, and ultrasonic seal.

[0222] The packaging material of the present invention is filled with contents through its opening, and the opening is then heat-sealed to produce a product using the packaging material of the present invention. The contents to be filled include confectioneries such as rice crackers, bean snacks, nuts, biscuits, cookies, wafer snacks, marshmallows, pies, semi-dried cakes, candies, and snacks; staple foods such as bread, snack noodles, instant noodles, dried noodles, pasta, aseptically packaged cooked rice, rice porridge, porridge, packaged rice cakes, and cereal foods; processed agricultural products such as pickles, boiled beans, natto, miso, frozen tofu, tofu, nametake mushrooms, konjac, processed wild vegetables, jams, peanut cream, salads, frozen vegetables, and processed potatoes; processed livestock products such as ham, bacon, sausages, processed chicken products, and corned beef; and fish ham and sausages. Examples of suitable packaging materials include processed seafood products such as fish paste products, kamaboko (fish paste), nori (seaweed paste), tsukudani (simmered foods in soy sauce), dried bonito flakes, salted fish, smoked salmon, and spicy cod roe, fruit pulp such as peaches, mandarin oranges, pineapples, apples, pears, and cherries, vegetables such as corn, asparagus, mushrooms, onions, carrots, radishes, and potatoes, prepared foods such as frozen and chilled prepared foods, including hamburger steaks, meatballs, fried seafood, gyoza (dumplings), and croquettes, dairy products such as butter, margarine, cheese, cream, instant creamy powder, and infant formula, liquid seasonings, retort curry, and pet food. The packaging material of the present invention can also be used as a packaging material for cigarettes, pharmaceuticals such as disposable body warmers and infusion packs, cosmetics, and vacuum insulation materials.

[0223] <Recycling method> The laminate of the present invention and packaging materials made of the laminate have excellent recyclability and can be used as raw materials for recycled plastics. The recycled plastics of the present invention are produced by recycling the laminate and packaging materials of the present invention as raw materials. The recycled plastics of the present invention can be obtained, for example, by peeling the laminate and packaging materials of the present invention into their respective substrates (peeling step), separating them by resin type (separation and recovery step), melt-kneading them, and then pelletizing them.

[0224] (Peeling Step) By immersing the laminate and packaging material of the present invention in a release agent for a certain period of time, the adhesive and printing ink can be peeled from the substrate and separated into a single-layer film. The laminate and packaging material of the present invention can be easily peeled off in warm water of 55°C or higher, so warm water can be used as the release agent. However, release agents containing various surfactants such as basic compounds, hydrophilic alcohols, anionic surfactants, nonionic surfactants, silicone surfactants, fluorine-containing surfactants, and biosurfactants in addition to water, or other additives, may also be used.

[0225] When a film having a vapor-deposited layer of a metal or metal oxide is used as the substrate, the use of a release agent containing a basic compound is preferable because it dissolves these layers, making the laminate easy to peel and minimizing the effect on the physical properties of the recycled pellets. Even when such a substrate is used, if any of the first to fourth resin layers described above is formed in contact with the vapor-deposited layer, the vapor-deposited layer can be removed from the film even by using hot water at 55°C or higher as the release agent.

[0226] As the water, pure water such as tap water, ion-exchanged water, ultrafiltered water, reverse osmosis water, distilled water, or ultrapure water can be used. From the viewpoint of long-term storage, it is preferable to use water that has been sterilized by ultraviolet irradiation or addition of hydrogen peroxide, etc., because this can prevent the growth of mold or bacteria. When a stripping agent containing a basic compound is used, it is preferable to use water with a hardness of 120 ppm or less, and more preferably water with a hardness of 80 ppm or less.

[0227] Examples of basic compounds include sodium hydroxide, potassium hydroxide, sodium carbonate, and calcium hydroxide. When the stripping agent contains a basic compound, the concentration of the basic compound is preferably 0.01% by mass or more and 5% by mass or less. The basic compound is adjusted so that the pH of the stripping agent is about 10 to 14.

[0228] The hydrophilic alcohol is an aliphatic alcohol that can be mixed with water in any ratio. Examples of hydrophilic alcohols include methanol, ethanol, 1-propanol, 2-propanol, ethylene glycol, and glycerin. These can be used alone or in combination of two or more, with ethanol being preferred. When the release agent contains a hydrophilic alcohol, its content is preferably 1% by mass or more and less than 60% by mass of the release agent.

[0229] The immersion time in the release agent is not particularly limited, but is, for example, 10 minutes or more and less than 5 hours. The immersion step in the release agent may be performed only once or may be performed multiple times. When the immersion step is performed multiple times, the release agents used may be the same or different.

[0230] The peeling of the laminate and packaging material is preferably carried out by heating to 55° C. or higher and 85° C. or lower, and more preferably to 70° C. or higher and 85° C. or lower. The heating method is not particularly limited, and known heating methods using heat rays, infrared rays, microwaves, etc. can be used. The treatment tank used for immersion in the release agent is preferably equipped with a reflux condenser for refluxing the heated and evaporated release agent.

[0231] The release agent is preferably stirred during immersion in the release agent. Examples of stirring methods include mechanically stirring the dispersion of the laminated film contained in a treatment tank with a stirring blade, water-jet stirring with a water pump, and bubbling with an inert gas such as nitrogen gas. Several methods may also be used in combination. This allows for more efficient separation of the laminate.

[0232] During the immersion in the stripping agent, ultrasonic vibrations may be applied to the stripping solution, for example, by attaching an ultrasonic vibrator to the treatment tank.

[0233] (Sorting and recovery process) After the peeling process, the release agent contains floating or dissolved adhesive and printing ink that have been peeled off from the laminate, film pieces (first substrate, second substrate, etc.) that have formed single layers when the laminate has been separated by peeling of the adhesive, and metal pieces (if the laminate contains a metal layer or a metal vapor deposition layer). In the sorting and recovery process, these are removed from the release agent and sorted and recovered.

[0234] As an example of a specific method, for example, flotation separation is used to separate light plastics (floating materials), such as polyolefins (polypropylene, polyethylene, etc.), from heavy materials (such as condensation synthetic films (polyester, nylon, etc.) or metal foils (heavier than polyolefins), and the heavy materials are removed. The recovered plastics are then washed and dehydrated, and then centrifuged to separate plastics with different specific gravities. For example, plastics can be separated into plastics containing vinyl chloride resins, polyethylene terephthalate, etc., which sink in water and have a specific gravity of 1 or more, and plastics containing olefin-based resins (such as polyethylene and polypropylene) that do not contain vinyl chloride resin. By appropriately changing the blending ratio of the liquid used for separation, for example, water and organic solvent, film fragments with various different specific gravities can be separated and recovered.

[0235] (Recycling of Release Agent) The release agent used in the peeling step of the laminate is also preferably recovered and reused after removing components other than the film pieces, such as adhesive layer pieces and printed layer pieces peeled from the laminate. Examples of a method for removing components other than the film pieces include filtration.

[0236] Components such as adhesive layer fragments and printed layer fragments can be pulverized by shear forces applied by stirring, which is often performed in the peeling process. If the adhesive layer fragments and printed layer fragments are pulverized too much in the peeling process, they may not be able to be filtered out completely depending on the opening size of the filter, and the adhesive layer fragments and printed layer fragments may remain in the release agent after filtration, causing the release agent to become discolored. If a filter with a small opening size is used to suppress discoloration of the release agent after filtration, the filtration will take a long time.

[0237] In the laminate of the present invention, particularly when a first resin layer and a second resin layer are provided and a layer such as a printed layer or an adhesive layer is sandwiched between them (for example, first substrate / first resin layer / either or both of the printed layer and the adhesive layer / second resin layer / second substrate), or when a film having a metal or metal oxide vapor deposition layer is used as the second substrate and a printed layer or an adhesive layer is sandwiched between the first resin layer and the vapor deposition layer provided on the second substrate (for example, first substrate / first resin layer / either or both of the printed layer and the adhesive layer / second substrate having a metal or metal vapor deposition layer), after the printed layer or adhesive layer is peeled from the first substrate and the second substrate, it is not too fine, and even a filter with a relatively large opening diameter can recover the printed layer fragments or adhesive layer fragments, and the release agent can be efficiently filtered. This is also true when the laminate of the present invention includes a third substrate.

[0238] The opening size of the filter is adjusted appropriately in consideration of the filtration efficiency of the release agent and the coloration degree of the release agent after filtration, and is, for example, 10 μm to 200 μm. As described above, when a printed layer or adhesive layer is disposed between two resin layers (e.g., a first resin layer and a second resin layer, a first resin layer and a third resin layer, or a second resin layer and a fourth resin layer), or when a printed layer or adhesive layer is disposed between a resin layer (any of the first to fourth resin layers) and a vapor-deposited layer of a metal or metal oxide, the opening size of the filter used to filter the release agent can be, for example, 30 μm to 200 μm, for example, 50 μm to 200 μm, or for another example, 100 μm to 200 μm.

[0239] (Pelletization) The film pieces collected by resin type in the separation and collection process are heated and melted at 120 to 280°C and then kneaded. The melting temperature can be adjusted taking into consideration the glass transition temperature and melting temperature of the resin, the shape when pelletized, and the pressure applied in the molding process. The screw rotation speed during kneading is, for example, 50 to 1000 RPM.

[0240] The melt-kneaded film pieces are cooled and shredded to form recycled plastic pellets. Examples of pelletization methods include, but are not limited to, hot cutting and strand cutting. To prevent foreign matter from being mixed into the pellets, it is preferable that a screen mesh be provided at the discharge section of the melt-kneaded laminate or packaging material. Examples of screen mesh include plain weave, twill weave, plain dutch weave, and twill dutch weave, as well as punched metal types. Taking into consideration the pressure and clogging of the discharge section, the screen mesh size is preferably 40 mesh or larger, more preferably 80 mesh or larger, and even more preferably 120 mesh or larger. Examples of cooling methods include air cooling, wind cooling, and water cooling. In the present invention, a water cooling step is preferably included. Cooling to 20°C to 80°C is preferable, and cooling to 30°C to 60°C is more preferable.

[0241] The recycled plastic of the present invention may contain known additives, such as at least one antioxidant selected from the group consisting of phenolic and phosphorus-based additives, at least one lubricant selected from the group consisting of fatty acid amides, alkylene fatty acid amides, metal soaps, and esters, a hindered amine weather stabilizer, a wax having an acid value of 5 mg KOH / g or less, and at least one antistatic agent selected from the group consisting of fatty acid sulfonates and fatty acid esters.

[0242] The recycled plastic of the present invention may contain virgin plastic as a raw material in addition to the laminate and packaging material of the present invention. The virgin plastic to be added is of the same resin type as the film pieces. The virgin plastic may be added when pelletizing the film pieces, or when molding the pelletized recycled plastic of the present invention. The virgin plastic may be added both when pelletizing and when molding the recycled plastic. The amount of virgin plastic used when pelletizing the film pieces is, for example, in a film pieces:virgin plastic ratio range of 100:0 to 25:75 (mass ratio). The amount of virgin plastic used when molding the pelletized recycled plastic of the present invention is, for example, in a recycled plastic:virgin plastic ratio range of 100:0 to 25:75 (mass ratio).

[0243] (Crushing Step) A crushing step of the laminate may be carried out prior to the step of immersing the laminate in a release agent. This allows for an increased amount of the edge surface of the laminate that comes into contact with the release agent, thereby shortening the time required to peel the laminate. On the other hand, the separated laminate may then be separated by gravity sorting or the like, and in this case, it is preferable that the film pieces are not too small. Taking these factors into consideration, in the crushing step, it is preferable to crush (including cutting) the laminate into small rectangular pieces with sides of approximately 5 to 60 mm. The crushing method may be so-called wet crushing, in which crushing is carried out in water or a cleaning solution, or dry crushing, in which crushing is carried out in an air atmosphere without the presence of a liquid such as a solvent.

[0244] The wet crusher is not particularly limited, but is preferably a wet crusher that can crush, disperse, mix, and pump solids in a liquid simultaneously. Specifically, it is preferably a crusher that has a mechanism for crushing solids in a liquid by shear force and / or friction force, and also has a mechanism for crushing and pumping plastic films. Examples of such wet crushers include a wet crushing pump, a colloid mill, and an attritor.

[0245] The dry crusher is not particularly limited, but examples of the dry crusher that can be used include a mycoloider, a mass colloider, a ball mill, a power mill, a pin mill, an airflow crusher (jet mill), a shear friction crusher, a cutter crusher, an impact crusher (hammer mill, ball mill), a roll crusher, a homogenizer, and an ultrasonic crusher.

[0246] (Washing process) The crushed laminate pieces are preferably subjected to a washing process before being sent to the peeling process. In the washing process, the pieces are placed in a washing container storing a washing liquid such as water or a detergent aqueous solution, and stirred in the washing container to wash away organic matter (food residue, oily stains, etc.) and inorganic matter (sand, dust, etc.) adhering to the laminate. Next, the laminate pieces are transferred to a rinsing container storing rinsing water, rinsed, and then drained.

[0247] The recycled plastic of the present invention can be used as a raw material for various plastic products. Examples of plastic products include, but are not limited to, transportation pallets and containers, containers such as bottles, hangers, stationery, pots and cups, disposable cutlery, and play equipment. The recycled plastic can also be recycled as film, or the recycled film can be molded and used as, for example, cushioning material for transporting fruit, but is not limited to this.

[0248] The present invention will be described in more detail below with reference to specific synthesis examples and examples, but the present invention is not limited to these examples. In the following examples, "parts" and "%" represent "parts by mass" and "% by mass", respectively, unless otherwise specified.

[0249] <Preparation of Coating Agent> (Preparation of Coating Agent) Coating agents were prepared according to the formulations shown in Tables 1 and 2. The compounds used in preparing the coating agents are as follows. Polyvinyl alcohols 1 and 2 are soluble in a 1:1 (mass ratio) solution of water and ethanol at 25°C at a concentration of 5% by mass or more, and a solution in which a 5% by mass vinyl alcohol polymer is dissolved in a 1:1 (mass ratio) solution of water and ethanol has a viscosity of 200 mPa·s or less at 25°C. Polyvinyl alcohols 3, 4, and 5 do not dissolve in a 1:1 (mass ratio) solution of ethanol at 25°C at a concentration of 5% by mass or more, and precipitate out. (Polyvinyl alcohol 1) Nichigo G-polymer (AZF8035Q), manufactured by Mitsubishi Chemical Corporation, weight average molecular weight 24,000, solid content 100% (Polyvinyl alcohol 2) Polyvinyl alcohol with a vinyl acetate-derived structure / ethylene-derived structure / propylene-derived structure = 96 / 3 / 1 (mol%), weight average molecular weight 48,000, solid content 100% (Polyvinyl alcohol 3) J-POVAL JF-05, manufactured by Nippon Vinyl Acetate & Poval Co., Ltd., weight average molecular weight 22,000, solid content 100% (Polyvinyl alcohol 4) J-POVAL JF-17, manufactured by Nippon Vinyl Acetate & Poval Co., Ltd., weight average molecular weight 75,000, solid content 100% (Polyvinyl alcohol 5) KURARAY POVAL 60-98, manufactured by Kuraray Co., Ltd., weight average molecular weight 106,000, solid content 100% (polyethyleneimine) Epomin P-1000, manufactured by Nippon Shokubai Co., Ltd., solid content 30%

[0250]

[0251]

[0252] The PEI content in the table refers to the content of polyalkyleneimine in the total amount of polyvinyl alcohol and polyalkyleneimine used in preparing the coating agent. In the table, Tg refers to the glass transition temperature of the dried coating film of each coating agent. In the table, viscosity refers to the viscosity of each coating agent at 25°C. For coating agents 7, 8, and 9, polyvinyl alcohol precipitated, making it impossible to measure the viscosity.

[0253] <Production of Evaluation Samples> (Sample 1) A coating amount (solid content) of 0.5 g / m was applied to a first substrate using a gravure printing machine equipped with a gravure plate having a plate depth of 22 μm. ２ The coating agent was applied in a solid state so that the thickness became 1 / 2 mm, and the coating agent was dried by passing it through an oven at 70° C., and then left at room temperature for one day to form a first resin layer.

[0254] Next, an adhesive was applied onto the first resin layer, and the first resin layer was laminated with a second substrate, followed by aging at 40°C for 3 days to obtain Sample 1 of first substrate / first resin layer / adhesive layer / second substrate.

[0255] (Sample 2) A first resin layer was provided on a first substrate in the same manner as Sample 1. Next, a urethane-based laminating ink (Finart R794 white, manufactured by DIC Corporation) was adjusted to 15 seconds (25°C) using a Zahn Cup #3 manufactured by Rigo Co., Ltd., and printed solidly on the first resin layer using a gravure printing machine equipped with a gravure plate with a plate depth of 43 μm. The ink was then dried or cured by passing through an oven at 70°C to form a printed layer.

[0256] Next, an adhesive was applied onto the printed layer, and the printed layer was attached to a second substrate, followed by aging at 40°C for 3 days to obtain Sample 2 of first substrate / first resin layer / printed layer / adhesive layer / second substrate.

[0257] (Sample 3) A first resin layer was provided on a first substrate in the same manner as in Sample 1. A coating agent was applied to a second substrate in a solid form using a gravure printing machine equipped with a gravure plate with a plate depth of 22 μm, and the coating agent was dried by passing through an oven at 70° C., and then left at room temperature for one day to form a second resin layer.

[0258] Next, an adhesive was applied onto the first resin layer, and the first resin layer was bonded to the surface of the second substrate on which the second resin layer was provided, followed by aging at 40°C for 3 days to obtain Sample 3 of first substrate / first resin layer / adhesive layer / second resin layer / second substrate.

[0259] (Sample 4) A first resin layer was provided on a first substrate, and a second resin layer was provided on a second substrate, in the same manner as Sample 3. A printed layer was provided on the first resin layer in the same manner as Sample 2. An adhesive was applied to the printed layer, which was then attached to the surface of the second substrate on which the second resin layer was provided, and aging was performed at 40°C for 3 days to obtain Sample 4 of first substrate / first resin layer / printed layer / adhesive layer / second resin layer / second substrate.

[0260] (Samples 5 and 6) Samples 5 and 6 were prepared in the same manner as Samples 1 and 2, except that the first resin layer was not provided.

[0261] The combinations of the first substrate, second substrate, coating agent, and adhesive used in the production of Samples 1 to 6 are shown in Tables 4 to 17. Details of the first substrate, second substrate, and adhesive in the tables are as follows: Coating agents 7 to 9 could not be applied using the above method, and no evaluation samples were produced.

[0262] (First substrate) OPP: P2161 (film thickness 20 μm) manufactured by Toyobo Co., Ltd. PET: E5100 (film thickness 12 μm) manufactured by Toyobo Co., Ltd.

[0263] (Second substrate) CPP: P1128 (film thickness 30 μm) manufactured by Toyobo Co., Ltd. VMCPP: 2203 (film thickness 25 μm) manufactured by Toray Advanced Film Co., Ltd.

[0264] (Adhesive) Adhesive 1: A mixture of 1 part of DIC DRY (registered trademark) LX-470EL and 1 part of SP-60, manufactured by DIC Corporation, diluted with ethyl acetate was used. The coating amount (solid content) was 2.5 g / m ２ After applying the adhesive, the solvent was dried with a dryer before bonding to the CPP film. Adhesive 2: A mixture of 60 parts of DIC DRY (registered trademark) LX-500 and 1 part of KW-75, both manufactured by DIC Corporation, diluted with ethyl acetate was used. The coating amount (solid content) was 2.5 g / m ２ After the adhesive was applied, the solvent was dried with a dryer before the film was attached to the CPP film.

[0265] Adhesive 3: 800 parts of soybean oil, 225 parts of maleic anhydride, and 0.5 parts of phosphoric acid were placed in a flask equipped with a stirrer, a thermometer, and a nitrogen gas inlet tube, and the mixture was heated to 180° C. After reacting at 180° C. for 3 hours, the temperature was lowered to 100° C., and 200 parts of tung oil was added and reacted for another 3 hours to obtain an oil containing an acid anhydride group.

[0266] A polyester reaction vessel equipped with a stirrer, thermometer, nitrogen gas inlet tube, distillation tube, and water separator was charged with 220 parts of diethylene glycol, 344 parts of neopentyl glycol, 286 parts of adipic acid, 287 parts of isophthalic acid, and 0.1 parts of tetraisopropyl titanate, and gradually heated so that the temperature at the top of the distillation tube did not exceed 100 ° C. The internal temperature was maintained at 240 ° C. The esterification reaction was terminated when the acid value became 2.0 mhKOH / g or less, and a polyester polyol having a hydroxyl value of 180 mgKOH / g was obtained.

[0267] A mixture of 100 parts of the oil having an acid anhydride group synthesized above, 33.53 parts of polyester polyol, and 12.24 parts of Adeka Polyether EDP-450 (manufactured by ADEKA Corporation, polypropylene glycol containing two tertiary amines in the molecule, molecular weight 450, hydroxyl value 500 mgKOH / g) was used as adhesive 3. The coating amount (solid content) was 2.5 to 3.0 g / m ２ After applying an adhesive, the laminate was laminated with a CPP film.

[0268] <Evaluation> (Blocking resistance) Coating agents 1 to 6 were each applied in a solid form to an OPP film (P2161, manufactured by Toyobo Co., Ltd.) having a thickness of 20 μm using a gravure printing machine equipped with a gravure plate with a plate depth of 22 μm, and the film was dried by passing through an oven at 70° C., and then left at room temperature for one day to form a first resin layer. Evaluation sample 7 having a size of 5 cm × 5 cm was cut out from the OPP film having the first resin layer formed thereon.

[0269] The untreated side of a 5 cm x 5 cm OPP film was placed on the first resin layer of evaluation sample 7, and the film was subjected to a pressure of 0.5 kg / cm ２After applying a load of 1000 kJ / min and leaving it for 24 hours in an atmosphere of 40°C and 80% humidity, the state when the evaluation sample and the OPP film were peeled off was evaluated according to the following criteria, and the results are summarized in Table 3. ⊚: No peeling noise was generated, and the untreated surface of the OPP film was not soiled. ◯: No peeling noise was generated, and the untreated surface of the OPP film was not soiled, but there was a slight tackiness on the surface of the first resin layer. △: Peeling noise was generated, and the untreated surface of the OPP film was not soiled, but there was a slight tackiness on the surface of the first resin layer. ×: Peeling noise was generated, and there was soiling on the untreated surface of the OPP film.

[0270]

[0271] (Laminate Strength) The laminate sample obtained above was cut into a length of 300 mm and a width of 15 mm to prepare a test piece. Using an Instron tensile tester, the sample was pulled at a peel rate of 300 mm / min in an environment of 25°C to measure the T-peel strength (N). This test was carried out five times, and the average value was calculated and evaluated according to the following criteria. The results are summarized in Tables 4 to 17. ◯: 0.5 N / 15 mm or more ×: Less than 0.5 N / 15 mm

[0272] (Delamination Property) The laminate sample obtained above was cut into a 20 mm x 20 mm piece to prepare a test piece. The test piece was immersed in Treatment Solution 1 (2% NaOH aqueous solution) at 70°C and stirred at 400 rpm for 1 hour using a magnetic stirrer, after which the test piece was removed. After washing with ion-exchanged water and drying, the adhesive peeling area (%) was measured and evaluated according to the following criteria, with the results summarized in Tables 4 to 17. The delamination property was evaluated in the same manner as above, except that Treatment Solution 2 (warm water) was used instead of Treatment Solution 1, and the results are summarized in Tables 4 to 17. 5: The first substrate and the second substrate are 100% peeled off, and the printed layer and adhesive layer are completely peeled off from both the first substrate and the second substrate. Peeled pieces of the first substrate, second substrate, printed layer and adhesive layer can be collected separately. 4: The first substrate and the second substrate are 100% peeled off, but part of the printed layer or adhesive layer remains on the first substrate or the second substrate. 3: The peeled area between the first substrate and the second substrate is 50% or more but less than 100%. 2: The peeled area between the first substrate and the second substrate is 10% or more but less than 50%. 1: The peeled area between the first substrate and the second substrate is less than 10%.

[0273] (Recyclability) After the delamination test, the release agent was filtered through a nylon strainer with 90 mesh / inch and an opening diameter of 185 μm, and the state of the filtered laminate sample and the presence or absence of coloration in the release agent after filtration were visually confirmed. Evaluation was performed using the following two levels, and the results are summarized in Tables 4 to 17. ○: The first substrate, second substrate, printed layer piece, and adhesive piece could be recovered separately, and no coloration was observed in the release agent after filtration. ×: The first substrate, second substrate, printed layer piece, and adhesive piece could not be recovered separately, and coloration was observed in the release agent after filtration.

[0274]

[0275]

[0276]

[0277]

[0278]

[0279]

[0280]

[0281]

[0282]

[0283]

[0284]

[0285]

[0286]

[0287]

Claims

1. a first substrate; a second substrate; and an adhesive layer disposed between the first substrate and the second substrate; a first resin layer disposed between the first substrate and the adhesive layer; the first resin layer contains a first vinyl alcohol-based polymer and a first polyalkyleneimine, the first vinyl alcohol polymer is soluble in a 1:1 (mass ratio) solution of water and ethanol at 25°C in an amount of 5% by mass or more, and a solution in which the vinyl alcohol polymer is dissolved in a 1:1 (mass ratio) solution of water and ethanol at 25°C in an amount of 5% by mass has a viscosity of 200 mPa s or less at 25°C; The laminate, wherein the glass transition temperature of the first resin layer is 40°C or higher and 80°C or lower.

2. 2. The laminate according to claim 1, wherein the glass transition temperature of the first resin layer is 50°C or higher and 70°C or lower.

3. 2. The laminate according to claim 1, wherein the content of the first polyalkyleneimine in the total amount of the first vinyl alcohol polymer and the first polyalkyleneimine is 1% by mass or more and 25% by mass or less.

4. a second resin layer between the adhesive layer and the second substrate; the second resin layer contains a second vinyl alcohol-based polymer and a second polyalkyleneimine, the second vinyl alcohol polymer is soluble in a 1:1 (mass ratio) solution of water and ethanol at 25°C in an amount of 5% by mass or more, and a solution in which the vinyl alcohol polymer is dissolved in a 1:1 (mass ratio) solution of water and ethanol at 25°C in an amount of 5% by mass has a viscosity of 200 mPa s or less at 25°C; 2. The laminate according to claim 1, wherein the second resin layer has a glass transition temperature of 40°C or higher and 80°C or lower.

5. The laminate according to claim 1 , further comprising a metal vapor deposition layer or an inorganic vapor deposition layer between the first substrate and the first resin layer.

6. The laminate according to claim 1 , further comprising a printed layer between the first resin layer and the adhesive layer.

7. a first resin layer disposed between the first substrate and the adhesive layer, the first resin layer comprising a first polyvinyl alcohol and a first polyalkyleneimine, the first vinyl alcohol-based polymer being soluble in a 1:1 (mass ratio) solution of water and ethanol at 25°C at a concentration of 5% by mass or more, the viscosity of a solution obtained by dissolving the vinyl alcohol-based polymer in a 1:1 (mass ratio) solution of water and ethanol at 25°C at a concentration of 5% by mass being 200 mPa s or less, and the glass transition temperature of the first resin layer being 40°C or higher and 80°C or lower, the first resin layer comprising a first polyvinyl alcohol and a first polyalkyleneimine, the first vinyl alcohol-based polymer being soluble in a 1:1 (mass ratio) solution of water and ethanol at a concentration of 5% by mass or more, the viscosity of the solution obtained by dissolving the vinyl alcohol-based polymer in a 1:1 (mass ratio) solution of water and ethanol at 25°C being 200 mPa s or less, and the glass transition temperature of the first resin layer being 40°C or higher and 80°C or lower, the first resin layer comprising a first polyvinyl alcohol and a first polyalkyleneimine, the first resin layer being soluble in a 1:1 (mass ratio) solution of water and ethanol at a concentration of 5% by mass or more, the viscosity of the solution being 200 mPa s or less at 25°C, the viscosity of the solution being 200 mPa s or less at 25°C, the glass transition temperature of the first resin layer being 40°C or higher and 80°C or lower, the first resin layer being immersed in a release agent to peel the first substrate from the second substrate.

8. The recycling method according to claim 7, wherein the release agent is heated to a temperature of 55°C or higher and 85°C or lower.

9. The recycling method according to claim 7, wherein the release agent is hot water at a temperature of 55°C or higher and 85°C or lower.

10. The recycling method according to claim 7, wherein the release agent is recovered and filtered through a filter having an opening diameter of 10 μm or more and 200 μm or less before being reused.

11. 8. The recycling method according to claim 7, wherein the laminate comprises a second resin layer between the adhesive layer and the second base material, the second resin layer comprising a second vinyl alcohol-based polymer and a second polyalkyleneimine, the second vinyl alcohol-based polymer is soluble at 5% by mass or more in a 1:1 (mass ratio) solution of water and ethanol at 25°C, the viscosity of a solution in which the vinyl alcohol-based polymer is dissolved at 5% by mass in the 1:1 (mass ratio) solution of water and ethanol at 25°C is 200 mPa s or less, and the glass transition temperature of the second resin layer is 40°C or higher and 80°C or lower.

12. a separation and recovery step of recovering the first substrate from the release agent that has been subjected to the peeling step; The recycling method according to claim 7, further comprising a pelletizing step of melting and kneading the first base material recovered in the separating and recovering step.

13. The recycling method according to claim 12, wherein in the pelletizing step, the first substrate recovered in the separating and recovering step and virgin plastic of the same resin type as the first substrate are melted and kneaded.

14. The recycling method according to claim 13, wherein the mass ratio of the first substrate to the virgin plastic is 100:0 to 25:75.