Adhesives, laminates, packaging materials

Abstract

Provided are: a two-component curable adhesive that has excellent releasability when immersed in an alkali aqueous solution but still maintains performance as an adhesive; and a laminate and a packaging material obtained using the adhesive.　Provided is a two-component curable adhesive that includes: an isocyanate composition (X) that includes a polyisocyanate compound (A); and an isocyanate-reactive composition (Y) that includes an active hydrogen group–containing compound (B). The active hydrogen group–containing compound (B) includes hydroxyl groups and acid groups. The average functional group number of hydroxyl groups in the active hydrogen group–containing compound (B) is 1.5–3.0, and the average functional group number of acid groups in the active hydrogen group–containing compound (B) is 0.2–2.0. Also provided are a laminate and a packaging material obtained using the adhesive.

Description

[Technical Field]

[0001] The present invention relates to an adhesive, a laminate obtained by using the adhesive, and a packaging material. [Background technology]

[0002] Laminates used in various packaging materials, labels, etc. are provided with design, functionality, storage stability, convenience, and transportability by laminating a wide variety of substrates such as plastic films, metal foils, and paper, and in particular, packages obtained by molding such laminates into bags are used as packages for foods, medicines, detergents, etc. Two-component adhesives that combine a polyisocyanate composition and a polyol composition are widely known as adhesives used to bond these substrates together.

[0003] In recent years, the recycling of packaging materials made of such laminates has been actively studied. Generally, a method of recycling waste plastics containing a mixture of thermoplastic resins and thermosetting resins by separating them based on their specific gravity is known, but separation is difficult when the materials are bonded together with adhesive. For this reason, the use of an alkaline aqueous solution to peel off the laminate has been studied (Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-131484 [Patent Document 2] Japanese Patent Application Publication No. 11-209677 Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a two-component curing adhesive that exhibits excellent releasability when immersed in an alkaline aqueous solution while maintaining adhesive performance, and a laminate and packaging material obtained using the adhesive. [Means for solving the problem]

[0006] Specifically, the present invention relates to a two-component curing adhesive comprising an isocyanate composition (X) containing a polyisocyanate compound (A) and an isocyanate-reactive composition (Y) containing an active hydrogen group-containing compound (B), wherein the active hydrogen group-containing compound (B) contains a hydroxyl group and an acid group, the average functionality of the hydroxyl groups in the active hydrogen group-containing compound (B) is 1.5 or more and 3.0 or less, and the average functionality of the acid groups in the active hydrogen group-containing compound (B) is 0.2 or more and 2.0 or less.

[0007] The present invention further relates to a laminate including a first substrate, a second substrate, and an adhesive layer that bonds the first substrate and the second substrate, wherein the adhesive layer is a cured coating film of the above-mentioned two-component curing adhesive, and to a packaging material comprising the laminate. [Effects of the Invention]

[0008] The adhesive of the present invention can provide a two-component curing adhesive that maintains adhesive performance while exhibiting excellent releasability when immersed in an alkaline aqueous solution, as well as a laminate and packaging material that are excellent in both adhesive performance and releasability and are easily recyclable. DETAILED DESCRIPTION OF THE INVENTION

[0009] <Adhesive> The adhesive of the present invention is a two-component curing adhesive comprising an isocyanate composition (X) and an isocyanate-reactive composition (Y). The adhesive of the present invention will be described in detail below.

[0010] (Isocyanate composition (X)) The isocyanate composition (X) contains a polyisocyanate compound (A) having multiple isocyanate groups. The polyisocyanate compound (A) 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.

[0011] 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 called 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.

[0012] The aromatic aliphatic 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.

[0013] Examples of aliphatic diisocyanates include, but are not limited to, 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.

[0014] 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.

[0015] Examples of polyols used in the synthesis of urethane prepolymers 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, 2,2,4-trimethyl-1,3-pentanediol, and dimer diol; aliphatic polyols such as trimethylolethane, trimethylolpropane, glycerin, hexanetriol, and pentaerythritol;

[0016] Polyether polyols obtained by ring-opening polymerization of aliphatic diols and / or aliphatic polyols 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;

[0017] Lactone-based polyester polyols obtained by polycondensation reaction of aliphatic diols and / or aliphatic polyols with various lactones such as lactanoids and ε-caprolactone; polyester polyols obtained by polycondensation reaction of aliphatic diols and / or aliphatic polyols with polycarboxylic acids;

[0018] Bisphenols such as bisphenol A and bisphenol F; Examples include alkylene oxide adducts of bisphenol obtained by adding ethylene oxide, propylene oxide, etc. to bisphenols such as bisphenol A and bisphenol F. These may be used alone or in combination of two or more.

[0019] Examples of polycarboxylic acids that can be used in the synthesis of polyester polyols include aliphatic polycarboxylic acids such as malonic acid, ethylmalonic acid, dimethylmalonic acid, succinic acid, 2,2-dimethylsuccinic acid, succinic anhydride, alkenylsuccinic anhydride, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, fumaric acid, maleic acid, maleic anhydride, itaconic acid, dimer acid, and trimer acid;

[0020] Alkyl esters of aliphatic polycarboxylic acids such as dimethyl malonate, diethyl malonate, dimethyl succinate, dimethyl glutarate, dimethyl adipate, diethyl pimelate, diethyl sebacate, dimethyl fumarate, diethyl fumarate, dimethyl maleate, and diethyl maleate;

[0021] Alicyclic polycarboxylic acids such as 1,1-cyclopentanedicarboxylic acid, 1,2-cyclopentanedicarboxylic acid, 1,3-cyclopentanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, tetrahydrophthalic anhydride, 4-methylhexahydrophthalic anhydride, hexahydrophthalic anhydride, cyclohexane-1,2,4-tricarboxylic acid-1,2-anhydride, himic anhydride, and HET anhydride;

[0022] Aromatic polycarboxylic acids such as orthophthalic acid, terephthalic acid, isophthalic acid, phthalic anhydride, 1,4-naphthalenedicarboxylic acid, 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 2,3-naphthalenedicarboxylic anhydride, naphthalic acid, trimellitic acid, trimellitic anhydride, pyromellitic acid, pyromellitic anhydride, biphenyldicarboxylic acid, 1,2-bis(phenoxy)ethane-p,p'-dicarboxylic acid, benzophenonetetracarboxylic acid, benzophenonetetracarboxylic dianhydride, 5-sodium sulfoisophthalic acid, tetrachlorophthalic anhydride, and tetrabromophthalic anhydride;

[0023] Methyl esters of aromatic polycarboxylic acids such as dimethyl terephthalic acid and dimethyl 2,6-naphthalenedicarboxylate; These can be used alone or in combination of two or more.

[0024] When the polyol used in synthesizing the urethane prepolymer is a polyester polyol, the polyester polyol is preferably a reaction product of a polycarboxylic acid and a polyhydric alcohol, and the polycarboxylic acid preferably contains at least one selected from aliphatic polycarboxylic acids and alkyl esters of aliphatic polycarboxylic acids. The proportion of the at least one selected from aliphatic polycarboxylic acids and alkyl esters of aliphatic polycarboxylic acids in the polycarboxylic acid can be adjusted as appropriate, but is, for example, 20% by mass or more. The total amount of the polycarboxylic acid may be at least one selected from aliphatic polycarboxylic acids and alkyl esters of aliphatic polycarboxylic acids.

[0025] The polyol used in synthesizing the urethane prepolymer preferably has a number average molecular weight of 200 to 3000. In this specification, the number average molecular weight is a value measured by gel permeation chromatography (GPC) under the following conditions.

[0026] Measuring device: Tosoh Corporation HLC-8320GPC Column: Tosoh Corporation TSKgel 4000HXL, TSKgel 3000HXL, TSKgel 2000HXL, TSKgel 1000HXL Detector: RI (differential refractometer) Data processing: Tosoh Corporation Multistation GPC-8020modelII Measurement conditions: Column temperature 40°C Solvent: Tetrahydrofuran Flow rate 0.35ml / min Standard: Monodisperse polystyrene Sample: 100 μl of tetrahydrofuran solution containing 0.2% by mass of resin solids filtered through a microfilter

[0027] When the polyisocyanate compound (A) is a urethane prepolymer, the equivalent ratio [NCO] / [OH] of the isocyanate groups to the hydroxyl groups to be reacted is preferably in the range of 1.5 to 8.0, since this brings the viscosity of the adhesive into an appropriate range and improves the coatability.

[0028] The polyisocyanate compound (A) preferably contains at least one selected from the group consisting of biuret, nurate, adduct, and allophanate forms of aliphatic diisocyanates, and urethane prepolymers of aromatic diisocyanates, and more preferably contains at least one selected from allophanate, biuret, and urethane prepolymers of aliphatic diisocyanates. The proportion of these suitable polyisocyanate compounds in the polyisocyanate compound (A) can be adjusted as appropriate, but is, for example, 1% by mass or more. The entire amount of the polyisocyanate compound (A) may be these suitable polyisocyanate compounds.

[0029] In a preferred embodiment of the adhesive of the present invention, the isocyanate composition (X) contains a bifunctional polyisocyanate compound (A), and the isocyanate-reactive composition (Y), described below, contains an active hydrogen group-containing compound (B) having a hydroxyl value of 45 mgKOH / g or more and 300 mgKOH / g or less. As the bifunctional polyisocyanate compound (A), for example, an allophanate of a diisocyanate or a urethane prepolymer of a diisocyanate and a diol is preferably used. The amount of the bifunctional polyisocyanate compound (A) can be appropriately adjusted. For example, the bifunctional polyisocyanate compound (A) is used in such a manner that the molar ratio [NCO] / [OH] of the isocyanate groups of the bifunctional polyisocyanate compound (A) to the hydroxyl groups of the active hydrogen group-containing compound (B) is 0.8 to 3.0.

[0030] In a preferred embodiment of the adhesive of the present invention, the isocyanate composition (X) contains a trifunctional or higher polyisocyanate compound (A), and the isocyanate-reactive composition (Y) described below contains an active hydrogen group-containing compound (B) having a hydroxyl value of 1 mgKOH / g or more and 60 mgKOH / g or less. The trifunctional or higher polyisocyanate compound (A) preferably contains, for example, a biuret of a diisocyanate or a urethane prepolymer of a diisocyanate and a trifunctional or higher polyol. The amount of the trifunctional polyisocyanate compound (A) can be appropriately adjusted. For example, the trifunctional polyisocyanate compound (A) is used in such a manner that the molar ratio [NCO] / [OH] of the isocyanate groups of the trifunctional polyisocyanate compound (A) to the hydroxyl groups of the active hydrogen group-containing compound (B) is 0.8 to 3.0.

[0031] In one preferred embodiment of the adhesive of the present invention, the isocyanate composition (X) contains a prepolymer that is a reaction product of an aromatic diisocyanate and a polyol, and the isocyanate-reactive composition (Y) described below contains an active hydrogen group-containing compound (B) with a hydroxyl value of 1 mgKOH / g or more and 300 mgKOH / g or less. The amount of prepolymer blended can be adjusted appropriately, and for example, the amount is used so that the molar ratio [NCO] / [OH] of the isocyanate groups in the prepolymer to the hydroxyl groups of the active hydrogen group-containing compound (B) is in the range of 0.8 to 3.0.

[0032] When the two-component curing adhesive of the present invention is a solventless type, the viscosity of the polyisocyanate composition (X) is adjusted to a range suitable for the non-solvent lamination method. For example, the viscosity at 40°C is adjusted to be in the range of 500 to 5000 mPas, more preferably 500 to 3000 mPas. The viscosity of the polyisocyanate composition (X) can be adjusted, for example, by the amount of urethane prepolymer or the amount of low-molecular-weight isocyanate compound.

[0033] When the two-component curing adhesive of the present invention is a solvent-based adhesive, the viscosity of the polyisocyanate composition (X) can be adjusted by an organic solvent, which will be described later.

[0034] (Isocyanate-reactive composition (Y)) (Active hydrogen group-containing compound (B)) The isocyanate-reactive composition (Y) used in the adhesive of the present invention contains an active hydrogen group-containing compound (B). The active hydrogen group-containing compound (B) contains a hydroxyl group and an acid group. The average functionality of the hydroxyl groups in the active hydrogen group-containing compound (B) is 1.5 to 3.0, and the average functionality of the acid groups in the active hydrogen group-containing compound (B) is 0.2 to 2.0. Such an active hydrogen group-containing compound (B) can be obtained, for example, by acid-modifying a polyol having an average functionality of 2.01 to 3.0. Alternatively, it can be obtained by mixing a bifunctional polyol compound and / or a trifunctional or higher functional polyol compound in which some of the hydroxyl groups have been acid-modified with a bifunctional polyol compound and / or a trifunctional or higher functional polyol compound in which the hydroxyl groups have not been acid-modified. The active hydrogen group-containing compound (B) is preferably obtained by acid-modifying a polyol having an average functionality of 2.01 to 3.0.

[0035] The average number of hydroxyl groups in the active hydrogen group-containing compound (B) is calculated by dividing the moles of hydroxyl groups in the active hydrogen group-containing compound (B) by the moles of the active hydrogen group-containing compound (B). The moles of hydroxyl groups in the active hydrogen group-containing compound (B) are calculated from the hydroxyl value of the active hydrogen group-containing compound before acid modification (hereinafter referred to as the active hydrogen group-containing compound (b) for convenience) and the moles of the acid group-containing compound used for modification. The moles of the active hydrogen group-containing compound (B) are calculated by the moles of the active hydrogen group-containing compound (b). The average number of functional groups of the acid groups contained in the active hydrogen group-containing compound (B) is calculated in the same manner.

[0036] Examples of the difunctional or trifunctional polyol compound used in preparing the active hydrogen group-containing compound (B) include glycols such as ethylene glycol, 1,2-propanediol, 1,3-propanediol, 2-methyl-1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, dimethylbutanediol, butylethylpropanediol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, bishydroxyethoxybenzene, 1,4-cyclohexanediol, and 1,4-cyclohexanedimethanol;

[0037] trifunctional or tetrafunctional aliphatic alcohols such as glycerin, trimethylolpropane, and pentaerythritol; Bisphenols such as bisphenol A, bisphenol F, hydrogenated bisphenol A, and hydrogenated bisphenol F; Dimer diol;

[0038] polyether polyols 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 such as glycol, trifunctional or tetrafunctional aliphatic alcohol, etc.;

[0039] polyester polyols (1) which are reaction products of polyesters obtained by ring-opening polymerization of cyclic ester compounds such as propiolactone, butyrolactone, ε-caprolactone, σ-valerolactone, and β-methyl-σ-valerolactone with polyhydric alcohols such as the above-mentioned glycols, glycerin, trimethylolpropane, and pentaerythritol; Polyester polyol (2) obtained by reacting a difunctional polyol such as glycol, dimer diol, or bisphenol with a polycarboxylic acid: (3) a polyester polyol obtained by reacting a trifunctional or tetrafunctional aliphatic alcohol with a polycarboxylic acid; (4) polyester polyols obtained by reacting a difunctional polyol with a trifunctional or tetrafunctional aliphatic alcohol and a polycarboxylic acid; Polyester polyols (5), which are polymers of hydroxyl acids such as dimethylolpropionic acid and castor oil fatty acid;

[0040] (1) a polyurethane polyol obtained by polymerizing at least one selected from a difunctional polyol, a trifunctional or tetrafunctional aliphatic alcohol with an isocyanate compound; Polyether urethane polyol (2) obtained by further increasing the molecular weight of polyether polyol with an isocyanate compound; Polyester polyurethane polyol (3) obtained by polymerizing polyester polyols (1) to (5) with an isocyanate compound; a polyester polyether polyurethane polyol (4) obtained by reacting at least one of the polyester polyols (1) to (5), a polyether polyol, and an isocyanate compound;

[0041] Examples include castor oil-based polyols such as castor oil, dehydrated castor oil, hardened castor oil which is a hydrogenated castor oil, and castor oil-based alkylene oxide 5 to 50 mole adducts, and mixtures thereof.

[0042] These can be used alone or in combination of two or more. The polycarboxylic acids used in the synthesis of the polyester polyols (1) to (5) can be the same as those exemplified as raw materials for the polyester polyols used in the synthesis of the above-mentioned urethane prepolymer.

[0043] The acid group-containing compound used to modify these polyol compounds can be any compound having an acid group and a functional group capable of reacting with a hydroxyl group, without any particular limitation. More specifically, phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, benzophenonetetracarboxylic anhydride, dodecenylsuccinic anhydride, polyadipic anhydride, polyazelaic anhydride, polysebacic anhydride, poly(ethyloctadecanedioic) anhydride, poly(phenylhexadecanedioic) anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, hexahydrophthalic anhydride, methylhimic anhydride, trialkyltetrahydrophthalic anhydride, methylcyclohexene dicarboxylic anhydride, Examples of the acid anhydride include acid anhydrides such as methylcyclohexene tetracarboxylic acid anhydride, ethylene glycol bistrimellitate dianhydride, HET anhydride, Nadic anhydride, methylnadic anhydride, 5-(2,5-dioxotetrahydro-3-furanyl)-3-methyl-3-cyclohexane-1,2-dicarboxylic acid anhydride, 3,4-dicarboxy-1,2,3,4-tetrahydro-1-naphthalene succinic acid dianhydride, and 1-methyl-dicarboxy-1,2,3,4-tetrahydro-1-naphthalene succinic acid dianhydride, as well as compounds obtained by modifying these acid anhydrides with glycol.

[0044] Examples of glycols that can be used to modify the acid anhydride include alkylene glycols such as ethylene glycol, propylene glycol, and neopentyl glycol; polyether glycols such as polyethylene glycol, polypropylene glycol, and polytetramethylene ether glycol; and copolymer polyether glycols of two or more of these glycols and / or polyether glycols.

[0045] The number average molecular weight of the active hydrogen group-containing compound (B) can be adjusted appropriately depending on the desired physical properties, but is preferably 500 or more and 6,000 or less, for example.

[0046] (Acid group-containing compound (C)) The adhesive of the present invention also preferably contains an acid group-containing compound (C), such as a resin (C1) having an acid group or a low molecular weight compound (C2) having an acid group. The acid group-containing compound (C) is a compound having an acid group and an acid value of 120 mg KOH / g or more and 350 mg KOH / g or less. Examples of the resin (C1) having an acidic group include resins having an acid value such as rosin-modified maleic acid resins and rosin-modified fumaric acid resins; radical copolymer resins such as (meth)acrylic resins, styrene-(meth)acrylic resins, styrene-maleic (anhydride) resins, and terpene-maleic (anhydride) resins, which are copolymerized with polymerizable monomers having an acidic group, such as polymerizable monomers having a carboxyl group, such as acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, cinnamic acid, or acid anhydrides thereof, polymerizable monomers having a sulfonic acid group, such as sulfonated styrene, and polymerizable monomers having a sulfonamide group, such as vinylbenzenesulfonamide; and acid-modified polyolefin resins, which can be used singly or in combination.

[0047] Examples of the low molecular weight compound (C2) having an acidic group include saturated fatty acids such as lauric acid, myristic acid, palmitic acid, margaric acid, and stearic acid; unsaturated fatty acids such as oleic acid, linoleic acid, linolenic acid, arachidonic acid, eicosapentaenoic acid, docosahexaenoic acid, and sorbic acid; hydroxy acids such as lactic acid, malic acid, and citric acid; aromatic carboxylic acids such as benzoic acid, phthalic acid, isophthalic acid, terephthalic acid, salicylic acid, gallic acid, mellitic acid, and cinnamic acid; dicarboxylic acids such as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, fumaric acid, and maleic acid; tricarboxylic acids such as aconitic acid; oxocarboxylic acids such as pyruvic acid and oxaloacetic acid; carboxylic acid derivatives such as amino acids and nitrocarboxylic acids; and acid anhydrides such as trimellitic anhydride and pyromellitic anhydride. These can be used singly or in combination.

[0048] The acid group-containing compound (C) preferably has at least one of a glass transition point, a softening point, and a melting point of 100° C. or higher. In addition, it is preferable that the acid group-containing compound (C) does not have a hydroxyl group.

[0049] The use of the acid group-containing compound (C) is particularly useful when a printed layer is present between the substrate and the cured coating film (adhesive layer) of the adhesive of the present invention in the laminate described below. Peeling of the printed layer from the substrate (deinking) and peeling of the adhesive layer from the substrate or the printed layer do not necessarily occur simultaneously, but in the present invention, deinking is promoted by the adhesive containing the acid group-containing compound (C).

[0050] The content of the acid group-containing compound (C) can be adjusted as appropriate, but is, for example, 2 to 20 parts by mass per 100 parts by mass of the solid content of the active hydrogen group-containing compound (B).

[0051] When the two-component curing adhesive of the present invention is a solventless type, the viscosity of the polyisocyanate-reactive composition (Y) is adjusted to a range suitable for the non-solvent lamination method. For example, the viscosity at 40°C is adjusted to be in the range of 100 to 5000 mPas, more preferably 500 to 3000 mPas. The viscosity of the polyisocyanate-reactive composition (Y) can be adjusted, for example, by the skeleton and number average molecular weight of the active hydrogen group-containing compound (B) and the plasticizer described below.

[0052] When the two-component curing adhesive of the present invention is a solvent-based adhesive, the viscosity of the polyisocyanate-reactive composition (Y) can be adjusted by the organic solvent described below.

[0053] (Other components of adhesive (D)) The adhesive of the present invention may contain components other than those described above. The other component (D) may be contained in either or both of the isocyanate composition (X) and the isocyanate-reactive composition (Y), or may be prepared separately and mixed with the isocyanate composition (X) and the isocyanate-reactive composition (Y) immediately before application of the adhesive. Each component will be described below.

[0054] (Catalyst (D1)) Examples of the catalyst (D1) include metal catalysts, amine catalysts, and aliphatic cyclic amide compounds.

[0055] Examples of the metal catalyst include metal complex catalysts, inorganic metal catalysts, and organic metal catalysts. Examples of the metal complex catalyst include acetylacetonate salts of metals selected from the group consisting of Fe (iron), Mn (manganese), Cu (copper), Zr (zirconium), Th (thorium), Ti (titanium), Al (aluminum), and Co (cobalt), such as iron acetylacetonate, manganese acetylacetonate, copper acetylacetonate, and zirconia acetylacetonate.

[0056] Examples of inorganic metal catalysts include those selected from Sn, Fe, Mn, Cu, Zr, Th, Ti, Al, Co, and the like.

[0057] Examples of the organometallic catalyst include organic zinc compounds such as zinc octylate, zinc neodecanoate, and zinc naphthenate; organic tin compounds such as stannous diacetate, stannous dioctoate, stannous dioleate, stannous dilaurate, dibutyltin diacetate, dibutyltin dilaurate, dioctyltin dilaurate, dibutyltin oxide, and dibutyltin dichloride; organic nickel compounds such as nickel octylate and nickel naphthenate; organic cobalt compounds such as cobalt octylate and cobalt naphthenate; organic bismuth compounds such as bismuth octylate, bismuth neodecanoate, and bismuth naphthenate; titanium compounds such as tetraisopropyloxytitanate, dibutyltitanium dichloride, tetrabutyltitanium, butoxytitanium trichloride, aliphatic diketones, aromatic diketones, and titanium chelate complexes having at least one alcohol having 2 to 10 carbon atoms as a ligand.

[0058] Examples of amine catalysts include triethylenediamine, 2-methyltriethylenediamine, quinuclidine, 2-methylquinuclidine, N,N,N',N'-tetramethylethylenediamine, N,N,N',N'-tetramethylpropylenediamine, N,N,N',N",N"-pentamethyldiethylenetriamine, N,N,N',N",N"-pentamethyl-(3-aminopropyl)ethylenediamine, N,N,N',N",N"-pentamethyldipropylenetriamine, N,N,N',N'-tetramethylhexamethylenediamine, bis(2-dimethylaminoethyl)ether, dimethylethanolamine, dimethylisopropanolamine, dimethylaminoethoxyethanol, N,N-dimethyl-N'-(2-hydroxyethyl)ethylenediamine, N,N-dimethyl-N'-(2-hydroxyethyl)propanediamine, bis(dimethylaminopropyl)amine, bis(dimethylaminopropyl)isopropanolamine, Propanolamine, 3-quinuclidinol, N,N,N',N'-tetramethylguanidine, 1,3,5-tris(N,N-dimethylaminopropyl)hexahydro-S-triazine, 1,8-diazabicyclo[5.4.0]undecene-7, N-methyl-N'-(2-dimethylaminoethyl)piperazine, N,N'-dimethylpiperazine, dimethylcyclohexylamine, N-methylmorpholine, N-ethylmorpholine, 1-methylimidazole, 1 ,2-dimethylimidazole, 1-isobutyl-2-methylimidazole, 1-dimethylaminopropylimidazole, N,N-dimethylhexanolamine, N-methyl-N'-(2-hydroxyethyl)piperazine, 1-(2-hydroxyethyl)imidazole, 1-(2-hydroxypropyl)imidazole, 1-(2-hydroxyethyl)-2-methylimidazole, 1-(2-hydroxypropyl)-2-methylimidazole, etc.

[0059] Examples of the aliphatic cyclic amide compound include δ-valerolactam, ε-caprolactam, ω-enantholactam, η-capryllactam, β-propiolactam, etc. Among these, ε-caprolactam is more effective in accelerating curing.

[0060] (Coupling agent (D2)) Examples of the coupling agent (D2) include silane coupling agents, titanate-based coupling agents, and aluminum-based coupling agents.

[0061] 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.

[0062] Examples of titanate coupling agents include tetraisopropoxytitanium, tetra-n-butoxytitanium, butyl titanate dimer, tetrastearyl titanate, titanium acetylacetonate, titanium lactate, tetraoctylene glycol titanate, titanium lactate, and tetrastearoxytitanium.

[0063] Examples of aluminum-based coupling agents include acetoalkoxyaluminum diisopropylate.

[0064] (Pigment (D3)) The pigment (D3) is not particularly limited, and examples thereof include organic pigments and inorganic pigments such as extender pigments, white pigments, black pigments, gray pigments, red pigments, brown pigments, green pigments, blue pigments, metal powder pigments, luminescent pigments, and pearlescent pigments listed in the Paint Raw Materials Handbook 1970 Edition (compiled by the Japan Paint Manufacturers Association), as well as plastic pigments.

[0065] Examples of extender pigments include precipitated barium sulfate, powdered barium sulfate, precipitated calcium carbonate, calcium bicarbonate, kansui stone, alumina white, silica, hydrous fine powdered silica (white carbon), ultrafine powdered anhydrous silica (aerosil), silica sand, talc, precipitated magnesium carbonate, bentonite, clay, kaolin, and yellow ochre.

[0066] Specific examples of organic pigments include various insoluble azo pigments such as Benzidine Yellow, Hansa Yellow, and Lake 4R; soluble azo pigments such as Lake C, Carmine 6B, and Bordeaux 10; various (copper) phthalocyanine pigments such as Phthalocyanine Blue and Phthalocyanine Green; various chlorine dye lakes such as Rhodamine Lake and Methyl Violet Lake; various mordant dye pigments such as Quinoline Lake and Fast Sky Blue; various vat dye pigments such as Anthraquinone pigments, Thioindigo pigments, and Perinone pigments; various quinacridone pigments such as Synchasia Red B; various dioxazine pigments such as Dioxazine Violet; various condensed azo pigments such as Chromophtal; and aniline black.

[0067] Examples of inorganic pigments include various chromates such as yellow lead, zinc chromate, and molybdate orange; various ferrocyanide compounds such as Prussian blue; various metal oxides such as titanium oxide, zinc white, Mapico yellow, iron oxide, red iron oxide, chrome oxide green, and zirconium oxide; various sulfides or selenides such as cadmium yellow, cadmium red, and mercury sulfide; various sulfates such as barium sulfate and lead sulfate; various silicates such as calcium silicate and ultramarine; various carbonates such as calcium carbonate and magnesium carbonate; various phosphates such as cobalt violet and manganese purple; various metal powder pigments such as aluminum powder, gold powder, silver powder, copper powder, bronze powder, and brass powder; flake pigments of these metals, mica flake pigments; metallic pigments and pearl pigments such as mica flake pigments coated with metal oxides and micaceous iron oxide pigments; graphite, carbon black, and the like.

[0068] Examples of plastic pigments include "Grandol PP-1000" and "PP-2000S" manufactured by DIC Corporation.

[0069] The pigment (D3) to be used may be appropriately selected depending on the purpose. For example, it is preferable to use inorganic oxides such as titanium oxide and zinc oxide as white pigments, as they have excellent durability, weather resistance, and design properties, and it is preferable to use carbon black as black pigments.

[0070] The amount of pigment (D3) to be blended is, for example, 1 to 400 parts by mass per 100 parts by mass of the total solid content of the isocyanate composition (X) and the isocyanate-reactive composition (Y), and is more preferably 10 to 300 parts by mass to improve adhesion and blocking resistance.

[0071] (Plasticizer (D4)) Examples of plasticizers include phthalic acid-based plasticizers, fatty acid-based plasticizers, aromatic polycarboxylic acid-based plasticizers, phosphoric acid-based plasticizers, polyol-based plasticizers, epoxy-based plasticizers, polyester-based plasticizers, and carbonate-based plasticizers.

[0072] Examples of phthalic acid plasticizers include phthalic acid ester plasticizers such as dimethyl phthalate, diethyl phthalate, dibutyl phthalate, diisobutyl phthalate, dihexyl phthalate, diheptyl phthalate, di-(2-ethylhexyl) phthalate, di-n-octyl phthalate, dinonyl phthalate, diisononyl phthalate, didecyl phthalate, diisodecyl phthalate, ditridecyl phthalate, diundecyl phthalate, dilauryl phthalate, distearyl phthalate, diphenyl phthalate, dibenzyl phthalate, butyl benzyl phthalate, dicyclohexyl phthalate, octyldecyl phthalate, dimethyl isophthalate, di-(2-ethylhexyl) isophthalate, and diisooctyl isophthalate; and tetrahydrophthalic acid ester plasticizers such as di-(2-ethylhexyl) tetrahydrophthalate, di-n-octyl tetrahydrophthalate, and diisodecyl tetrahydrophthalate.

[0073] Examples of fatty acid plasticizers include adipic acid plasticizers such as di-n-butyl adipate, di-(2-ethylhexyl) adipate, diisodecyl adipate, diisononyl adipate, di(C6-C10 alkyl) adipate, and dibutyl diglycol adipate; azelaic acid plasticizers such as di-n-hexyl azelate, di-(2-ethylhexyl) azelate, and diisooctyl azelate; and di-n-butyl sebacate and di-(2 Sebacic acid plasticizers such as di-n-butyl maleate, di-(2-ethylhexyl) sebacate, and diisononyl sebacate; maleic acid plasticizers such as dimethyl maleate, diethyl maleate, di-n-butyl maleate, and di-(2-ethylhexyl) maleate; fumaric acid plasticizers such as di-n-butyl fumarate and di-(2-ethylhexyl) fumarate; monomethyl itaconate, monobutyl itaconate, dimethyl itaconate, diethyl itaconate, and dibutyl itaconate; Examples of suitable plasticizers include itaconic acid-based plasticizers such as itaconate and di-(2-ethylhexyl) itaconate; stearic acid-based plasticizers such as n-butyl stearate, glycerin monostearate, and diethylene glycol distearate; oleic acid-based plasticizers such as butyl oleate, glyceryl monooleate, and diethylene glycol monooleate; citric acid-based plasticizers such as triethyl citrate, tri-n-butyl citrate, acetyl triethyl citrate, acetyl tributyl citrate, and acetyl tri-(2-ethylhexyl) citrate; ricinoleic acid-based plasticizers such as methyl acetyl ricinoleate, butyl acetyl ricinoleate, glyceryl monoricinoleate, and diethylene glycol monoricinoleate; and other fatty acid-based plasticizers such as diethylene glycol monolaurate, diethylene glycol dipelargonate, and pentaerythritol fatty acid esters.

[0074] Examples of aromatic polycarboxylic acid plasticizers include trimellitic acid plasticizers such as tri-n-hexyl trimellitate, tri-(2-ethylhexyl) trimellitate, tri-n-octyl trimellitate, triisooctyl trimellitate, triisononyl trimellitate, tridecyl trimellitate, and triisodecyl trimellitate; and pyromellitic acid plasticizers such as tetra-(2-ethylhexyl) pyromellitate and tetra-n-octyl pyromellitate.

[0075] Examples of phosphoric acid plasticizers include triethyl phosphate, tributyl phosphate, tri-(2-ethylhexyl) phosphate, tributoxyethyl phosphate, triphenyl phosphate, octyl diphenyl phosphate, cresyl diphenyl phosphate, cresyl phenyl phosphate, tricresyl phosphate, trixylenyl phosphate, tris(chloroethyl) phosphate, tris(chloropropyl) phosphate, tris(dichloropropyl) phosphate, and tris(isopropylphenyl) phosphate.

[0076] Examples of polyol-based plasticizers include glycol-based plasticizers such as diethylene glycol dibenzoate, dipropylene glycol dibenzoate, triethylene glycol dibenzoate, triethylene glycol di-(2-ethylbutyrate), triethylene glycol di-(2-ethylhexoate), and dibutylmethylene bisthioglycolate; and glycerin-based plasticizers such as glycerol monoacetate, glycerol triacetate, and glycerol tributyrate.

[0077] Examples of epoxy plasticizers include epoxidized soybean oil, epoxy butyl stearate, di-2-ethylhexyl epoxy hexahydrophthalate, diisodecyl epoxy hexahydrophthalate, epoxy triglyceride, epoxidized octyl oleate, and epoxidized decyl oleate.

[0078] Examples of polyester plasticizers include adipic acid polyesters, sebacic acid polyesters, and phthalic acid polyesters.

[0079] Examples of carbonate plasticizers include propylene carbonate and ethylene carbonate.

[0080] Other examples of the plasticizer include partially hydrogenated terphenyls, adhesive plasticizers, and polymerizable plasticizers such as diallyl phthalate, acrylic monomers and oligomers, etc. These plasticizers can be used alone or in combination of two or more.

[0081] (Phosphate compound (D5)) Examples of the phosphoric acid compound (D5) include phosphoric acid, pyrophosphoric acid, triphosphoric acid, methyl acid phosphate, ethyl acid phosphate, butyl acid phosphate, dibutyl phosphate, 2-ethylhexyl acid phosphate, bis(2-ethylhexyl) phosphate, isododecyl acid phosphate, butoxyethyl acid phosphate, oleyl acid phosphate, tetracosyl acid phosphate, 2-hydroxyethyl methacrylate acid phosphate, and polyoxyethylene alkyl ether phosphate.

[0082] (Adhesive Form) The adhesive of the present invention may be either solvent-based or solventless. The term "solvent-based" adhesive as used herein refers to a form used in a so-called dry lamination method, in which the adhesive is applied to a substrate, heated in an oven or the like to volatilize the organic solvent in the coating, and then laminated to another substrate. Either the isocyanate composition (X) or the isocyanate-reactive composition (Y), or both, contain a highly soluble organic solvent capable of dissolving the components of the isocyanate composition (X) or the isocyanate-reactive composition (Y) used in the present invention. When the adhesive of the present invention is solvent-based, the organic solvent used as a reaction medium during the production of the components of the isocyanate composition (X) or the isocyanate-reactive composition (Y) may also be used as a diluent during coating. Examples of organic solvents having high solubility include 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.

[0083] As used herein, the term "solventless" refers to an adhesive that is substantially free of the highly soluble organic solvents, particularly ethyl acetate or methyl ethyl ketone, in the isocyanate composition (X) or isocyanate-reactive composition (Y). The adhesive is applied to a substrate and then bonded to another substrate without heating in an oven or other device to volatilize the solvent. This is known as the "non-solvent lamination" method. This applies when trace amounts of organic solvent remain in the isocyanate composition (X) or isocyanate-reactive composition (Y) due to incomplete removal of the organic solvents used as reaction media during the production of the isocyanate composition (X) or isocyanate-reactive composition (Y) or their raw materials. Furthermore, when the isocyanate-reactive composition (Y) contains a low-molecular-weight alcohol, the low-molecular-weight alcohol reacts with the isocyanate composition (X) and becomes part of the coating, eliminating the need for volatilization after application. Therefore, this type of adhesive is also considered a solventless adhesive.

[0084] The adhesive of the present invention is preferably used by blending the isocyanate composition (X) and the isocyanate-reactive composition (Y) 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 0.8 to 3.0, more preferably 1.0 to 3.0.

[0085] The adhesive of the present invention is preferably adjusted so that the acid value after curing is 5 mgKOH / g or more and 50 mgKOH / g or less. The acid value of the adhesive can be adjusted by the acid value of the active hydrogen group-containing compound (B), the amount of the acid group-containing compound (C) added, the [NCO] / [OH] ratio between the isocyanate composition (X) and the isocyanate-reactive composition (Y), etc. This allows the adhesive to have even better peelability.

[0086] <Laminate> The laminate of the present invention is obtained by laminating multiple substrates (films or papers) using the adhesive of the present invention. There are no particular restrictions on the film used, and a film can be selected appropriately depending on the application. For example, for food packaging, polyolefin films such as polyethylene terephthalate (PET) film, polystyrene film, polyamide film, polyacrylonitrile film, polyethylene film (LLDPE: low-density polyethylene film, HDPE: high-density polyethylene film) and polypropylene film (CPP: non-oriented polypropylene film, OPP: biaxially oriented polypropylene film), polyvinyl alcohol film, ethylene-vinyl alcohol copolymer film, etc. may be mentioned.

[0087] 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.

[0088] 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.

[0089] Alternatively, a film laminated with a vapor-deposited layer of a metal such as aluminum, or a metal oxide such as silica or alumina, or a barrier film containing a gas barrier layer of polyvinyl alcohol, ethylene-vinyl alcohol copolymer, vinylidene chloride, etc. Using such a film can provide a laminate with barrier properties against water vapor, oxygen, alcohol, inert gases, volatile organic compounds (fragrances), etc.

[0090] The paper can be made from any known paper base material without any particular limitations. Specifically, it can be made using natural fibers for papermaking, such as wood pulp, on a known papermaking machine, but the papermaking conditions are not particularly specified. Examples of natural fibers for papermaking include wood pulp, such as softwood pulp and hardwood pulp; non-wood pulp, such as Manila hemp pulp, sisal hemp pulp, and flax pulp; and chemically modified versions of these pulps. Examples of pulp that can be used include chemical pulp produced by sulfate cooking, acidic, neutral, or alkaline sulfite cooking, or soda cooking, ground pulp, chemi-ground pulp, and thermomechanical pulp. Commercially available wood-free paper, coated paper, lined paper, impregnated paper, cardboard, and paperboard can also be used.

[0091] More specifically, the laminate has the following structure: (1) Substrate 1 / Adhesive layer 1 / Sealant film (2) Substrate 1 / Adhesive layer 1 / Metal-deposited unstretched film (3) Substrate 1 / Adhesive layer 1 / Metal vapor-deposited stretched film (4) Transparent vapor-deposited stretched film / adhesive layer 1 / sealant film (5) Substrate 1 / Adhesive layer 1 / Substrate 2 / Adhesive layer 2 / Sealant film (6) Substrate 1 / Adhesive layer 1 / Metal vapor-deposited stretched film / Adhesive layer 2 / Sealant film (7) Substrate 1 / Adhesive layer 1 / Transparent vapor-deposited stretched film / Adhesive layer 2 / Sealant film (8) Substrate 1 / Adhesive layer 1 / Metal layer / Adhesive layer 2 / Sealant film (9) Substrate 1 / Adhesive layer 1 / Substrate 2 / Adhesive layer 2 / Metal layer / Adhesive layer 3 / Sealant film (10) Substrate 1 / Adhesive layer 1 / Metal layer / Adhesive layer 2 / Substrate 2 / Adhesive layer 3 / Sealant film These include, but are not limited to:

[0092] Examples of the substrate 1 used in structure (1) include MDOPE film, OPE film, OPP film, PET film, nylon film, and paper. The substrate 1 may also be coated to improve gas barrier properties or ink receptivity when a printing layer (described later) is provided. Examples of commercially available coated substrate films 1 include K-OPP film and K-PET film. The adhesive layer 1 is a cured coating of the adhesive of the present invention. Examples of sealant films include CPP film, LLDPE film, and gas-barrier heat-seal film. A printing layer may be provided on the surface of the substrate 1 facing the adhesive layer 1 (when a coated substrate film 1 is used, the surface of the coating layer facing the adhesive layer 1) or on the surface opposite the adhesive layer 1. The printing layer is formed using various printing inks, such as gravure ink, flexographic ink, offset ink, stencil ink, and inkjet ink, using a common printing method that has traditionally been used to print on polymer films and paper.

[0093] Examples of the substrate 1 used in structures (2) and (3) include MDOPE film, OPE film, OPP film, PET film, paper, etc. The adhesive layer 1 is a cured coating of the adhesive of the present invention. Examples of metal-vapor-deposited unstretched films include CPP film, LLDPE film, and VM-CPP film and VM-LLDPE film, which are gas-barrier heat-sealable films to which a metal such as aluminum has been vapor-deposited. Examples of metal-vapor-deposited stretched films include MDOPE film, OPE film, and VM-MDOPE film, VM-OPE film, and VM-OPP film, which are OPP films to which a metal such as aluminum has been vapor-deposited. As in structure (1), a printing layer may be provided on either side of the substrate 1, or the substrate 1 may be coated with a coating for the purpose of improving ink receptivity, etc.

[0094] Examples of transparent vapor-deposited stretched films used in structure (4) include films obtained by depositing silica or alumina on MDOPE film, OPE film, OPP film, PET film, nylon film, etc. For the purpose of protecting the inorganic vapor-deposited layer of silica or alumina, a film with a coating on the vapor-deposited layer may also be used. The adhesive layer 1 is a cured coating of the adhesive of the present invention. Examples of sealant films include those similar to those in structure (1). A printed layer may be provided on the surface of the transparent vapor-deposited stretched film facing the adhesive layer 1 (when a film with a coating on the inorganic vapor-deposited layer is used, the surface of the coating layer facing the adhesive layer 1). The method of forming the printed layer is the same as in structure (1).

[0095] Examples of the substrate 1 used in structure (5) include PET film and paper. Examples of the substrate 2 include nylon film. Either the adhesive layer 1 or the adhesive layer 2 is a cured coating film of the adhesive of the present invention. Either the adhesive layer 1 or the adhesive layer 2 may be a cured coating film of the adhesive of the present invention. Examples of the sealant film include those similar to those in structure (1). As in structure (1), a printing layer may be provided on either side of the substrate 1, or the substrate 1 may be coated with a coating for the purpose of improving ink receptivity, etc.

[0096] Examples of the substrate 1 in structure (6) include those similar to those in structures (2) and (3). Examples of metal-vapor-deposited stretched films include VM-MDOPE film, VM-OPE film, VM-OPP film, and VM-PET film, which are obtained by vapor-depositing a metal such as aluminum on an MDOPE film, OPE film, OPP film, or PET film. Either adhesive layer 1 or adhesive layer 2 is a cured coating film of the adhesive of the present invention. Either adhesive layer 1 or adhesive layer 2 may be a cured coating film of the adhesive of the present invention. Examples of the sealant film include those similar to those in structure (1). As in structure (1), a printing layer may be provided on either side of the substrate 1, or the substrate 1 may be coated with a coating for the purpose of improving ink receptivity, etc.

[0097] Examples of the substrate 1 in structure (7) include PET film, paper, etc. Examples of the transparent vapor-deposited stretched film include those similar to those in structure (4). Either adhesive layer 1 or 2 is a cured coating film of the adhesive of the present invention. Both adhesive layer 1 and adhesive layer 2 may be a cured coating film of the adhesive of the present invention. Examples of the sealant film include those similar to those in structure (1). As in structure (1), a printing layer may be provided on either side of the substrate 1, or the substrate 1 may be coated with a coating for the purpose of improving ink receptivity, etc.

[0098] Examples of the substrate 1 in structure (8) include PET film, paper, etc. Examples of the metal layer include aluminum foil, etc. Either of the adhesive layers 1 and 2 is a cured coating film of the adhesive of the present invention. Either of the adhesive layers 1 and 2 may be a cured coating film of the adhesive of the present invention. Examples of the sealant film include those similar to those in structure (1). As in structure (1), a printing layer may be provided on either side of the substrate 1, or the substrate 1 may be coated with a coating for the purpose of improving ink receptivity, etc.

[0099] Examples of the substrate 1 in structures (9) and (10) include PET film, paper, etc. Examples of the substrate 2 include nylon film, etc. Examples of the metal layer include aluminum foil, etc. Any of the adhesive layers 1, 2, and 3 is a cured coating film of the adhesive of the present invention. Any of the adhesive layers 1, 2, and 3 may be a cured coating film of the adhesive of the present invention. Examples of the sealant film include those similar to those in structure (1). As in structure (1), a printing layer may be provided on either side of the substrate 1, or the substrate 1 may be coated with a coating for the purpose of improving ink receptivity, etc.

[0100] The printed layer may be formed using a deinkable ink (a printing ink designed to be easily peeled from the resin film when immersed in a basic solution). Forming the printed layer using a deinkable ink is preferred because it allows the printed layer to be easily peeled from the substrate in a shorter time, improving recyclability.

[0101] The coating may also be formed from a composition designed to improve adhesion between the printed layer and the substrate and to facilitate peeling from the resin film by immersion in a basic solution. This is preferable because it makes it easier to peel the printed layer from the laminate in a shorter time and improves recyclability. Examples of such compositions include, but are not limited to, compositions containing a resin having an acidic group and a composition containing an additive having an acidic group.

[0102] When the adhesive of the present invention is a solvent-based adhesive, the adhesive is applied to a film material substrate using a roll such as a gravure roll, and the organic solvent is evaporated by heating in an oven or the like, and then the other substrate is laminated to obtain the laminate of the present invention. After lamination, an aging treatment is preferably performed. The aging temperature is preferably room temperature to 80°C, and the aging time is preferably 12 to 240 hours.

[0103] When the adhesive of the present invention is a solventless type, the adhesive of the present invention, which has been preheated to about 40°C to 100°C, is applied to the film material serving as the substrate using a roll such as a gravure roll, and then the other substrate is immediately laminated to obtain the laminate of the present invention. After lamination, it is preferable to perform an aging treatment. The aging temperature is preferably room temperature to 70°C, and the aging time is preferably 6 to 240 hours.

[0104] The amount of adhesive applied is adjusted as needed. For example, in the case of a solvent-based adhesive, the solid content is 1 g / m. 2 More than 10g / m 2 Less than 2 g / m 2 More than 5g / m 2 Adjust the amount of adhesive to be as follows: For solvent-free adhesives, the amount of adhesive applied is, for example, 1 g / m 2 More than 5g / m 2 Less than 1 g / m 2 More than 3g / m 2 The following is the result.

[0105] <Packaging material> The packaging material of the present invention is obtained by forming the above-mentioned laminate into a bag shape and heat-sealing it to form a packaging material. The packaging material may take various forms, such as three-side sealed bags, four-side sealed bags, gusseted packaging bags, pillow packaging bags, Goebel-top type bottomed containers, Tetra Classic, Brueck type, tube containers, paper cups, and lids. The packaging material of the present invention may also be appropriately provided with an easy-opening treatment or resealing means.

[0106] 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. Examples of contents that can be filled include foods such as rice crackers, bean snacks, nuts, biscuits, cookies, wafer snacks, marshmallows, pies, semi-dried cakes, candies, and snacks; bread, snack noodles, instant noodles, dried noodles, pasta, aseptically packaged cooked rice, porridge, rice porridge, packaged rice cakes, and cereal foods; pickles, boiled beans, natto, miso, frozen tofu, tofu, nametake mushrooms, konjac, processed wild vegetables, jams, peanut cream, salads, frozen vegetables, and processed potatoes; livestock products such as ham, bacon, sausages, processed chicken, and corned beef; and fish, ham, and Examples of such foods include processed seafood products such as sausages, fish paste products, kamaboko, nori seaweed, tsukudani (simmered foods in soy sauce), bonito flakes, salted fish, smoked salmon, and spicy mentaiko; fruit pulp such as peaches, mandarin oranges, pineapples, apples, pears, and cherries; vegetables such as corn, asparagus, mushrooms, onions, carrots, radishes, and potatoes; cooked foods such as frozen and chilled prepared dishes, including hamburgers, meatballs, fried seafood, gyoza, and croquettes; dairy products such as butter, margarine, cheese, cream, instant creamy powder, and infant formula; liquid seasonings, retort curry, and pet food.

[0107] In addition, the present invention can also be used as a packaging material for various non-food products, such as cigarettes, disposable body warmers, medicines such as infusion packs, liquid laundry detergent, liquid kitchen detergent, liquid bath detergent, liquid bath soap, liquid shampoo, liquid conditioner, cosmetics such as lotion and emulsion, vacuum insulation materials, batteries, etc. The packaging material of the present invention can also be used as a secondary packaging material for packaging the above-mentioned containers.

[0108] <Method for separating and recovering laminate> The laminate of the present invention can be separated into its respective substrates and recovered by treatment using an alkaline solution, which is currently the most commonly used recycling treatment. For example, by immersing the laminate in an alkaline solution while heating and stirring at 20 to 90°C, the substrates and adhesive layer are peeled off, allowing them to be separated and recovered.

[0109] The alkaline solution used in the separation and recovery method is preferably an aqueous sodium hydroxide solution, an aqueous potassium hydroxide solution, etc. The aqueous sodium hydroxide solution or the aqueous potassium hydroxide solution has a concentration of preferably 0.5% by mass to 10% by mass, and more preferably 1% by mass to 5% by mass. The pH is preferably 10 or higher.

[0110] The alkaline solution may contain a water-soluble organic solvent. Examples of water-soluble organic solvents include methyl alcohol, ethyl alcohol, propyl alcohol, isopropyl alcohol, ethylene glycol monomethyl ether (methyl cellosolve), ethylene glycol monoethyl ether (cellosolve), ethylene glycol monobutyl ether (butyl cellosolve), ethylene glycol dibutyl ether, diethylene glycol monomethyl ether (methyl carbitol), diethylene glycol dimethyl ether, diethylene glycol monoethyl ether (carbitol), diethylene glycol diethyl ether (diethyl carbitol), diethylene glycol monobutyl ether (butyl carbitol), diethylene glycol dibutyl ether, triethylene glycol monomethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, methylene dimethyl ether (methylal), propylene glycol monobutyl ether, tetrahydrofuran, acetone, diacetone alcohol, acetonyl acetone, acetyl acetone, ethylene glycol monomethyl ether acetate (methyl cellosolve acetate), and diethylene glycol monomethyl ether acetate (methyl carbitol acetate). Examples include diethylene glycol monoethyl ether acetate (carbitol acetate), ethyl hydroxyisobutyrate, and ethyl lactate, which can be used alone or in combination of two or more.

[0111] The content of the water-soluble organic solvent in the alkaline solution is preferably 30% by mass to 70% by mass, and more preferably 40% by mass to 60% by mass.

[0112] The alkaline solution may contain a water-insoluble organic solvent. Examples of water-insoluble organic solvents include alcoholic solvents such as n-butanol, 2-butanol, isobutanol, and octanol; aliphatic hydrocarbon solvents such as hexane, heptane, and normal paraffin; aromatic hydrocarbon solvents such as benzene, toluene, xylene, and alkylbenzene; halogenated hydrocarbon solvents such as methylene chloride, 1-chlorobutane, 2-chlorobutane, 3-chlorobutane, and carbon tetrachloride; ester solvents such as methyl acetate, ethyl acetate, and butyl acetate; ketone solvents such as methyl isobutyl ketone, methyl ethyl ketone, and cyclohexanone; and ether solvents such as ethyl ether and butyl ether. These solvents may be used alone or in combination.

[0113] The alkaline solution may contain a surfactant, such as various anionic surfactants, nonionic surfactants, cationic surfactants, and amphoteric surfactants, with anionic surfactants and nonionic surfactants being preferred.

[0114] Examples of anionic surfactants include alkylbenzenesulfonates, alkylphenylsulfonates, alkylnaphthalenesulfonates, higher fatty acid salts, sulfate ester salts of higher fatty acid esters, sulfonates of higher fatty acid esters, sulfate ester salts and sulfonates of higher alcohol ethers, higher alkyl sulfosuccinates, polyoxyethylene alkyl ether carboxylates, polyoxyethylene alkyl ether sulfates, alkyl phosphates, and polyoxyethylene alkyl ether phosphates. Specific examples of these include dodecylbenzenesulfonate, isopropylnaphthalenesulfonate, monobutylphenylphenol monosulfonate, monobutylbiphenylsulfonate, and dibutylphenylphenol disulfonate.

[0115] Examples of nonionic surfactants include polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl ethers, polyoxyethylene fatty acid esters, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene sorbitol fatty acid esters, glycerin fatty acid esters, polyoxyethylene glycerin fatty acid esters, polyglycerin fatty acid esters, sucrose fatty acid esters, polyoxyethylene alkylamines, polyoxyethylene fatty acid amides, fatty acid alkylolamides, alkylalkanolamides, acetylene glycol, oxyethylene adducts of acetylene glycol, and polyethylene glycol polypropylene glycol block copolymers. Of these, polyoxyethylene nonylphenyl ether, polyoxyethylene octylphenyl ether, polyoxyethylene dodecylphenyl ether, polyoxyethylene alkyl ethers, polyoxyethylene fatty acid esters, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, fatty acid alkylolamides, acetylene glycol, oxyethylene adducts of acetylene glycol, and polyethylene glycol polypropylene glycol block copolymers are preferred.

[0116] Other surfactants that can be used include silicone surfactants such as polysiloxane oxyethylene adducts; fluorine-based surfactants such as perfluoroalkyl carboxylates, perfluoroalkyl sulfonates, and oxyethylene perfluoroalkyl ethers; and biosurfactants such as spiculisporic acid, rhamnolipid, and lysolecithin.

[0117] These surfactants can be used alone or in combination of two or more. When a surfactant is added, the amount added is preferably in the range of 0.001 to 2% by mass, more preferably 0.001 to 1.5% by mass, and even more preferably 0.01 to 1% by mass, based on the total amount of the alkaline solution.

[0118] The alkaline solution preferably contains a terpene compound, such as monoterpenes (α-pinene, β-pinene, limonene, β-phellandrene, α-terpinene, γ-terpinene, aucimene, myrcene, camphene, terpinolene, sylvestrene, sabinene, carene, tricyclene, and fenchene), sesquiterpenes (longifolene, caryophyllene, bisabolene, santalene, zingiberene, curcumene, cadinene, sesquibenihene, and cedrene), and diterpenes (campholene, podocarpulene, myrene, phyllocladene, and totarene) and other terpene hydrocarbons.

[0119] Monoterpene alcohols such as β-citronellol, geraniol, nerol, linalool, terpineol, carpeol, thuyl alcohol, pinocampheol, and fenchyl alcohol; sesquiterpene alcohols such as farnesol, nerolidol, cadinol, eudesmol, guayol, baturyl alcohol, carotol, lantheol, and kessoglycol; terpene alcohols such as phytol, sclareol, manol, hinokitiol, ferruginol, and totarol;

[0120] Terpene aldehydes such as citronellal, citral, cyclocitral, safranal, phellandral, and perillaldehyde,

[0121] Examples of terpene ketones include monoterpene ketones such as dagetone, ionone, irone, carbomenthone, carbotanacetone, piperitenone, thujone, and calone; sesquiterpene ketones such as cyperone, eremophilone, and zerumbone; and diterpene ketones such as sugiol and ketomanoyl oxide.

[0122] These may be used alone or in combination of two or more. Terpene hydrocarbons are preferred, and limonene is more preferred.

[0123] The content of the terpene compound can be adjusted as appropriate, but is preferably 0.1% by mass or more and 90% by mass or less, more preferably 1% by mass or more, and even more preferably 5% by mass or more, of the alkaline solution, and more preferably 50% by mass or less of the alkaline solution.

[0124] The laminate is immersed in an alkaline solution heated to 20 to 90°C in a treatment tank. There are no particular limitations on the heating method, and known heating methods using heat rays, infrared rays, microwaves, etc. can be used. Ultrasonic vibrations may be applied during immersion. For example, an ultrasonic vibrator can be attached to the treatment tank to apply ultrasonic vibrations to the alkaline solution.

[0125] The alkaline solution is preferably stirred when the laminate is immersed in. Examples of the stirring method include mechanically stirring the dispersion of the laminate contained in the treatment tank with a stirring blade, water jet stirring with a water jet pump, and bubbling with an inert gas such as nitrogen gas. These methods may be used in combination to efficiently peel off the laminate.

[0126] The time for immersing the laminate in the alkaline solution depends on the structure of the laminate, but is generally in the range of 2 minutes to 48 hours. If the immersion time is less than 2 minutes, the adhesive layer may not completely peel off from the laminate and may remain partially. The immersion in the alkaline solution may be performed once or in several divided steps.

[0127] In most cases, the laminate is provided with an adhesive and a printed ink layer for displaying a trade name or for providing decorativeness, but the printed ink layer can also be peeled off or dissolved by immersing the laminate in an alkaline solution. In addition, the laminate may be provided with a metal foil or vapor-deposited film such as aluminum, but the present invention can peel off or dissolve the metal foil or vapor-deposited film.

[0128] It is believed that the alkaline solution used in the separation and recovery method acts on the interface between the laminate and the adhesive or printing ink, significantly reducing the adhesive strength, thereby causing interfacial peeling between the laminate and the adhesive or printing ink. Normally, crosslinked coating films of reactive adhesives and the like hardly dissolve in any solution, but in the present invention, they are not dissolved but rather cause interfacial peeling, which is believed to enable efficient separation and recovery in a short time. [Example]

[0129] 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.

[0130] <Isocyanate composition (X)> (Isocyanate composition (X-1)) The biuret of HDI was diluted with ethyl acetate to a solid content of 70% to prepare an isocyanate composition (X-1).

[0131] (Isocyanate composition (X-2)) An allophanate of HDI (D101, manufactured by Asahi Kasei) was used as an isocyanate composition (X-2).

[0132] (Isocyanate composition (X-3)) A polyester reaction vessel equipped with a stirrer, a thermometer, a nitrogen gas inlet tube, a distillation tube, and a water separator was charged with 54.2 parts of adipic acid and 45.8 parts of diethylene glycol, and the mixture was gradually heated so that the temperature at the top of the distillation tube did not exceed 100° C., and the internal temperature was maintained at 220° C. The esterification reaction was terminated when the acid value reached 2.0 mgKOH / g or less, yielding an intermediate polyester polyol.

[0133] A flask equipped with a stirrer, thermometer, and nitrogen gas inlet tube was charged with 26 parts of 4,4'-diphenylmethane diisocyanate and 26 parts of 2,4'-diphenylmethane diisocyanate, and heated to 60°C while stirring under a nitrogen gas atmosphere. 43.2 parts of the intermediate polyester polyol synthesized above and 4.8 parts of polypropylene glycol with a number-average molecular weight of 1000 were added dropwise in several portions, and the mixture was stirred for 5-6 hours to complete the urethane reaction. A polyisocyanate compound with an NCO group content of 14.4% and a viscosity of 1000 mPa·s (25°C) was obtained and used as isocyanate composition (X-3).

[0134] <Isocyanate-reactive composition (Y)> (Isocyanate-reactive composition (Y-1)) (Synthesis of active hydrogen group-containing compound (B-1)) A flask equipped with a stirrer, thermometer, nitrogen gas inlet tube, rectification tube, water separator, etc. was charged with 10.5 parts of ethylene glycol, 10.1 parts of diethylene glycol, 12.7 parts of neopentyl glycol, 7.7 parts of trimethylolpropane, and 5.4 parts of dimer acid in a reaction vessel, and the mixture was stirred under nitrogen gas introduction and heated to 100 ° C. 10.4 parts of adipic acid, 21.6 parts of isophthalic acid, and 21.6 parts of terephthalic acid were added at 100-110 ° C., and the mixture was gradually heated so that the temperature at the top of the rectification tube did not exceed 100 ° C. The internal temperature was maintained at 260 ° C. and stirred for 8 hours to obtain an intermediate polyester polyol (b-1).

[0135] A flask equipped with a stirrer, thermometer, and nitrogen gas inlet tube was charged with 100 parts of intermediate polyester polyol (b-1) and 7.7 parts of trimellitic anhydride, and the mixture was heated to 75°C with stirring under a nitrogen gas atmosphere. The mixture was stirred for 8 hours to add the acid. The mixture was diluted with ethyl acetate to a nonvolatile content of 75%, yielding polyester polyol (B-1) with an acid value of 28.9 mgKOH / g and a viscosity of 1400 mPa·s.

[0136] To 100 parts of the obtained polyester polyol (B-1), 4 parts of Pine Crystal KE-604 (a rosin-modified maleic acid resin manufactured by Arakawa Chemical Industries, Ltd.) as an acid group-containing compound (C-1) were added and stirred, and the resulting mixture was used as an isocyanate-reactive composition (Y-1).

[0137] (Isocyanate-reactive compositions (Y-2) to (Y-10), (Y'-1) to (Y'-2)) (Synthesis of active hydrogen group-containing compounds (B-2), (B-3), and (B'-1)) Intermediate polyester polyols (b-2), (b-3), (b'-1) and polyester polyols (B-2), (B-3), (B'-1) were obtained in the same manner as intermediate polyester polyol (b-1) and polyester polyol (B-1), except that the polyhydric alcohol, polycarboxylic acid, amounts used, and reaction time used were changed to those shown in Tables 1 and 2. Details of the compounds shown in the tables are as follows. AA: Adipic acid IPA: Isophthalic acid TPA: Terephthalic acid DA: Dimer acid "Tsunodime 216" (aliphatic dibasic acid manufactured by Tsuno Foods Co., Ltd.) DEG: Diethylene glycol EG: Ethylene glycol NPG: Neopentyl glycol TMP: Trimethylolpropane

[0138] [Table 1]

[0139] [Table 2]

[0140] (Synthesis of active hydrogen group-containing compounds (B-4) and (B'-2)) A flask equipped with a stirrer, thermometer, nitrogen gas inlet tube, rectification tube, and water separator was charged with 39.2 parts by mass of diethylene glycol, 8.1 parts by mass of glycerin, and 52.7 parts by mass of adipic acid. The temperature was gradually increased under a normal pressure nitrogen stream to 220°C while the dehydration reaction was carried out, and the reaction was continued at 220°C. After confirming that the temperature at the top of the rectification column had dropped below 80°C, the rectification column was removed and replaced with a glass condenser. A line was connected from the nitrogen gas inlet tube to a vacuum pump, and the condensation reaction was carried out under a reduced pressure of 50 Torr until the specified acid value was reached, yielding intermediate polyester polyol (b-4). This was then used as polyester polyol (B'-2).

[0141] A flask equipped with a stirrer, thermometer, and nitrogen gas inlet tube was charged with 100 parts of intermediate polyester polyol (b-4) and 12.9 parts of trimellitic anhydride, and the mixture was heated to 75°C with stirring under a nitrogen gas atmosphere. The mixture was stirred for 8 hours to add the acid. The mixture was diluted with ethyl acetate to a nonvolatile content of 85%, yielding polyester polyol (B-4) with an acid value of 46.8 mg KOH / g and a viscosity of 1000 mPa s.

[0142] (Synthesis of active hydrogen group-containing compound (B-5)) A flask equipped with a stirrer, thermometer, and nitrogen gas inlet tube was charged with 100 parts of the intermediate polyester polyol (b-4) and 7.5 parts of trimellitic anhydride, and the mixture was heated to 75°C with stirring under a nitrogen gas atmosphere. The mixture was stirred for 8 hours to allow the acid to be added. The mixture was diluted with ethyl acetate to a nonvolatile content of 85%, yielding polyester polyol (B-5) with an acid value of 30.6 mgKOH / g and a viscosity of 800 mPa·s.

[0143] Table 3 shows the average number of functional groups and number average molecular weight of polyester polyols (B-4), (B-5), and (B′-2). The polyester polyols (B-2) to (B-5), (B'-1), and (B'-2) were blended with the acid group-containing compound (C) in the proportions shown in Table 4 to obtain isocyanate-reactive compositions (Y-2) to (Y-10), (Y'-1) to (Y'-2).

[0144] [Table 3]

[0145] <Preparation of adhesive> Adhesives of the Examples and Comparative Examples were obtained by mixing the isocyanate composition (X) and the isocyanate-reactive composition (Y) heated to 40°C in the formulations (solid content) shown in Tables 4 to 6. The acid value in the tables is the acid value of the cured coating film of the adhesive (a value calculated from the active hydrogen group-containing compound (B), acid group-containing compound (C) used, and the blending ratio [NCO] / [OH] between the isocyanate composition (X) and the isocyanate-reactive composition (Y)).

[0146] <Manufacturing of laminate> (OPP / adhesive layer / CPP) The adhesive of the example or comparative example was applied to an OPP film (manufactured by Toyobo Co., Ltd., P2161) in an amount (solid content) of 3 g / m 2 The adhesive was applied so that the adhesive layer was uniformly coated, and the adhesive layer was attached to a CPP film (P1128, manufactured by Toyobo Co., Ltd.) and aged at 40°C for 3 days to obtain a laminate of OPP / adhesive layer / CPP.

[0147] (OPP / printing layer (indigo) / printing layer (white) / adhesive layer / CPP) A urethane-based laminating ink (DIC Corporation, Finart R507 indigo) was adjusted to 15 seconds (25°C) using a Rigo Zahn Cup #3 and printed on an OPP film (Toyobo Co., Ltd., P2161) using a gravure printing machine equipped with a 43 μm deep gravure plate. The resulting print was then dried or cured by passing through a 70°C oven to form a printed layer (indigo). Next, a urethane-based laminating ink (DIC Corporation, Finart R794 white) was adjusted to 15 seconds (25°C) using a Rigo Zahn Cup #3 and printed on the printed layer (indigo) using a gravure printing machine equipped with a 43 μm deep gravure plate. The resulting print was then dried or cured by passing through a 70°C oven to form a printed layer (white). An adhesive of the example or comparative example was applied to the printed layer (white) in an amount (solids) of 3 g / m. 2The laminate was then laminated with a CPP film (P1128, manufactured by Toyobo Co., Ltd.) and aged at 40°C for 3 days to obtain a laminate of OPP / printed layer (indigo) / printed layer (white) / adhesive layer / CPP.

[0148] <Evaluation> (Adhesive strength) The OPP / adhesive / CPP laminate 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 test piece was pulled at a peel rate of 300 mm / min in an environment of 25°C, and the T-peel strength (N) between the OPP and CPP was measured over a 15 mm width. If the T-peel strength (N) was 0.7 N / 15 mm or more, or F (indicating film breakage), the peel strength was deemed sufficient. The results are summarized in Tables 4 to 6.

[0149] (peelability) The laminate obtained above was cut into 20mm x 20mm pieces to prepare test specimens. The test specimens were immersed in a release agent heated to 70°C and stirred at 400 rpm. After immersion, the test specimens were removed, washed with ion-exchanged water, dried, and the adhesive peeled area (%) was measured by coloring with neocarmine. Complete peeling was considered to be 100%. The immersion time was 3 hours. The release agent used was a mixture of 48 parts water and 50 parts ethanol with 2 parts sodium hydroxide dissolved in it. A peeled area (%) of 70% or more is considered acceptable, and a peeled area (%) of 90% or more is considered particularly excellent. The results are summarized in Tables 4 to 6.

[0150] [Table 4]

[0151] [Table 5]

[0152] [Table 6]

Claims

1. The present invention comprises an isocyanate composition (X) containing a polyisocyanate compound (A), an isocyanate-reactive composition (Y) containing an active hydrogen group-containing compound (B) and an acid group-containing compound (C), The active hydrogen group-containing compound (B) contains a hydroxyl group and an acid group, the average functional number of hydroxyl groups contained in the active hydrogen group-containing compound (B) is 1.5 or more and 3.0 or less; the average functional number of acid groups contained in the active hydrogen group-containing compound (B) is 0.2 or more and 2.0 or less; the polyisocyanate compound (A) includes a polyisocyanate compound obtained by reacting a polyol with diphenylmethane diisocyanate, the polyol including a polyester polyol which is a reaction product of a polycarboxylic acid and a polyhydric alcohol; The acid group-containing compound (C) has an acid value of 120 mgKOH / g or more and 350 mgKOH / g or less and does not have a hydroxyl group, the content of the acid group-containing compound (C) is 2 parts by mass or more and 20 parts by mass or less per 100 parts by mass of the solid content of the active hydrogen group-containing compound (B), the molar ratio (isocyanate group / hydroxyl group) of the isocyanate group contained in the isocyanate composition (X) to the hydroxyl group contained in the isocyanate-reactive composition (Y) is 0.8 or more and 3.0 or less, a two-component curing adhesive, wherein the acid value of the reaction product of the isocyanate composition (X) and the isocyanate-reactive composition (Y) is 5 mgKOH / g or more and 50 mgKOH / g or less;

2. The two-component curing adhesive according to claim 1 , wherein the polyisocyanate compound (A) and the polyol further contain polypropylene glycol.

3. 2. The two-component curing adhesive according to claim 1, wherein the active hydrogen group-containing compound (B) has a number average molecular weight of 1,600 or more and 6,000 or less.

4. 2. The two-component curing adhesive according to claim 1, wherein 20% by mass or more of the polycarboxylic acids used in synthesizing the polyester polyol contain at least one selected from aliphatic polycarboxylic acids and alkyl esters of aliphatic polycarboxylic acids.

5. The two-component curing adhesive according to claim 1 , wherein the acid group-containing compound (C) includes a resin (C1) having an acid group.

6. The two-component curing adhesive according to claim 1 , wherein the acid group-containing compound (C) includes a low molecular weight compound (C2) having an acid group.

7. 2. The two-component curing adhesive according to claim 1, wherein the acid group-containing compound (C) has at least one of a glass transition point, a softening point, and a melting point of 100[deg.] C. or higher.

8. A laminate comprising a first substrate, a second substrate, and an adhesive layer disposed between the first substrate and the second substrate, wherein the adhesive layer is a cured coating film of the two-component curing adhesive according to any one of claims 1 to 7.

9. The laminate according to claim 8 , further comprising a printed layer between the first substrate and the adhesive layer.

10. The laminate according to claim 9 , further comprising a primer layer between the first substrate and the printed layer.

11. A packaging material comprising the laminate according to claim 8.

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