Two-part curable adhesive, laminate, and packaging material

Abstract

Provided is a white adhesive with excellent oxygen barrier properties.　This two-part curable adhesive includes a polyol composition (X) and a polyisocyanate composition (Y). The polyol composition (X) includes a polyol compound (A) and a white pigment (B). The polyisocyanate composition (Y) includes an isocyanate compound (C). The polyol compound (A) is at least one selected from: polyester polyols (A1-1) obtained by polycondensation of a polycarboxylic acid including an ortho-orientated polycarboxylic acid with a polyhydric alcohol; polyester polyols (A1-2) having an isocyanuric ring; and polyester polyols (A1-3) having a polymerizable carbon-carbon double bond. The polyol compound (A) includes polyester polyols (A1) having a molecular weight of 200-2,000 g / mol.

Description

Two-component curing adhesives, laminates, and packaging materials

[0001] This invention relates to a two-component curing adhesive, a laminate, and a packaging material.

[0002] For packaging materials of food, medical products, cosmetics, and daily necessities, composites are used that are multilayer laminated of metal foils such as aluminum foil, films having a metal vapor-deposited layer or an inorganic oxide vapor-deposited layer, and plastic films such as polyethylene, polypropylene, polyvinyl chloride, polyester, and nylon. These laminates are formed by appropriately combining various plastic films, metal vapor-deposited films, or metal foils according to the required characteristics for each application and bonding them together with adhesives. As adhesives, two-component curing types consisting of a polyol composition and a polyisocyanate composition are generally used (for example, Patent Document 1).

[0003] Japanese Patent Publication No. 2014-101422

[0004] Packaging materials for the aforementioned applications often have a printed layer. This printed layer typically contains layers of printing inks in multiple colors, such as yellow, red, cyan, and white. However, the white ink layer can sometimes be omitted and replaced with an adhesive layer colored white by dispersing white pigment. Furthermore, in recent years, efforts have been made to develop easily recyclable packaging materials to reduce environmental impact. One such material is a laminate made by bonding olefin resin substrates together with an adhesive. Such laminates exhibit inferior oxygen barrier properties compared to laminates using, for example, polyester film. Therefore, there is a need for a white adhesive with excellent oxygen barrier properties that is suitable for use in laminates made by bonding olefin resin substrates together with an adhesive.

[0005] This invention has been made in view of these problems, and aims to provide a white adhesive with excellent oxygen barrier properties.

[0006] In other words, the present invention relates to a two-component curing adhesive comprising a polyol composition (X) and a polyisocyanate composition (Y), wherein the polyol composition (X) comprises a polyol compound (A) and a white pigment (B), and the polyisocyanate composition (Y) comprises an isocyanate compound (C), and the polyol compound (A) is at least one selected from polyester polyols (A1-1) obtained by polycondensation of a polycarboxylic acid containing an ortho-directing polycarboxylic acid and a polyhydric alcohol, polyester polyols having an isocyanuric ring (A1-2), and polyester polyols having a polymerizable carbon-carbon double bond (A1-3), and includes a polyester polyol (A1) having a molecular weight of 200 g / mol or more and a molecular weight of 2000 g / mol or less.

[0007] According to the present invention, a white adhesive with excellent oxygen barrier properties can be provided.

[0008] <Two-component curing adhesive> The adhesive of the present invention is a two-component curing adhesive comprising a polyol composition (X) containing a polyol compound (A) and a white pigment (B), and a polyisocyanate composition (Y) containing an isocyanate compound (C).

[0009] (Polyol composition (X)) (Polyol compound (A)) Polyol compound (A) is at least one selected from polyester polyols (A1-1) obtained by polycondensation of a polycarboxylic acid containing an ortho-directing polycarboxylic acid and a polyhydric alcohol, polyester polyols having an isocyanuric ring (A1-2), and polyester polyols having a polymerizable carbon-carbon double bond (A1-3), and includes polyester polyol (A1) having a molecular weight of 200 g / mol or more and a molecular weight of 2000 g / mol or less.

[0010] Examples of ortho-directing polycarboxylic acids used in the synthesis of polyester polyol (A1-1) include orthophthalic acid or its acid anhydride, naphthalene 2,3-dicarboxylic acid or its acid anhydride, naphthalene 1,2-dicarboxylic acid or its acid anhydride, anthraquinone 2,3-dicarboxylic acid or its acid anhydride, and 2,3-anthracenecarboxylic acid or its acid anhydride. These compounds may have substituents on any carbon atom of the aromatic ring. Examples of substituents include chloro group, bromo group, methyl group, ethyl group, i-propyl group, hydroxyl group, methoxy group, ethoxy group, phenoxy group, methylthio group, phenylthio group, cyano group, nitro group, amino group, phthalimide group, carboxyl group, carbamoyl group, N-ethylcarbamoyl group, phenyl group, or naphthyl group.

[0011] The polycarboxylic acid used in the synthesis of polyester polyol (A1-1) may include polycarboxylic acids other than ortho-directing polycarboxylic acids. Examples of polycarboxylic acids other than ortho-directing polycarboxylic acids 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, isophthalic acid, pyromellitic acid, trimellitic acid, 1,4-naphthalenedicarboxylic acid, 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, naphthalic acid, biphenyldicarboxylic 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 aromatic polycarboxylic acids, and one or more of these can be used in combination. Among these, succinic acid, 1,3-cyclopentanedicarboxylic acid, isophthalic acid, and their acid anhydrides are preferred.

[0012] When the polycarboxylic acid includes polycarboxylic acids other than ortho-directing polycarboxylic acids, it is preferable that the proportion of ortho-directing polycarboxylic acids to the total amount of polycarboxylic acids is 40 to 100% by mass.

[0013] The polyhydric alcohol used in the synthesis of polyester polyol (A1-1) preferably contains at least one selected from the group consisting of ethylene glycol, propylene glycol, butylene glycol, neopentyl glycol, and cyclohexanedimethanol, and more preferably contains ethylene glycol.

[0014] Polyhydric alcohols other than those listed above may be used in combination. Examples 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 dipentaerythulitol; hydroquinone, resorcinol, catechol, naphthalenediol, biphenol, bisphenol A, hisphenol F, tetramethylbiphenol, and aromatic polyhydric phenols such as ethylene oxide extensions thereof and hydrogenated alicyclic groups.

[0015] If the polyester polyol (A1-1) has three or more hydroxyl groups, some of the hydroxyl groups may be modified with a polycarboxylic acid or its acid anhydride. Preferably, the proportion of hydroxyl groups modified with a polycarboxylic acid is 1 / 3 or less of the total hydroxyl groups present in the polyester polyol (A1-1). 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.

[0016] Polyester polyol (A1-2) can be obtained, for example, by reacting a triol having an isocyanuric ring with a polycarboxylic acid containing an ortho-directing aromatic polycarboxylic acid and a polyhydric alcohol. Examples of triols having an isocyanuric ring include alkylene oxide adducts of isocyanuric acid such as 1,3,5-tris(2-hydroxyethyl)isocyanuric acid and 1,3,5-tris(2-hydroxypropyl)isocyanuric acid. The ortho-directing aromatic polycarboxylic acid, polycarboxylic acid, and polyhydric alcohol can be the same as those used in polyester polyol (A1-1).

[0017] As the triol compound having an isocyanuric ring, it is preferable to use 1,3,5-tris(2-hydroxyethyl)isocyanuric acid or 1,3,5-tris(2-hydroxypropyl)isocyanuric acid. As the ortho-directing aromatic polycarboxylic acid, it is preferable to use orthophthalic anhydride. As the polyhydric alcohol, it is preferable to use ethylene glycol.

[0018] Polyester polyols (A1-3) can be obtained by using components having polymerizable carbon-carbon double bonds as polycarboxylic acids and polyhydric alcohols.

[0019] Examples of polycarboxylic acids having polymerizable carbon-carbon double bonds include maleic anhydride, maleic acid, fumaric acid, 4-cyclohexene-1,2-dicarboxylic acid and its acid anhydride, and 3-methyl-4-cyclohexene-1,2-dicarboxylic acid and its acid anhydride. Maleic anhydride, maleic acid, and fumaric acid are preferred because it is presumed that the fewer carbon atoms there are, the less the molecular chain becomes excessively flexible and therefore less permeable to oxygen. Examples of polyhydric alcohols having polymerizable carbon-carbon double bonds include 2-butene-1,4-diol.

[0020] In addition to the above, polycarboxylic acids and polyhydric alcohols that do not have polymerizable carbon-carbon double bonds may be used in combination. As such polycarboxylic acids and polyhydric alcohols, those the same as those for polyester polyols (A1-1) and (A1-2) can be used. It is preferable to use at least one polycarboxylic acid selected from the group consisting of succinic acid, 1,3-cyclopentanedicarboxylic acid, orthophthalic acid, acid anhydride of orthophthalic acid, and isophthalic acid, and it is more preferable to use at least one of orthophthalic acid and its acid anhydride. It is preferable to use at least one polyhydric alcohol selected from the group consisting of ethylene glycol, propylene glycol, butylene glycol, neopentyl glycol, and cyclohexanedimethanol, and it is more preferable to use ethylene glycol.

[0021] The molecular weight of polyester polyol (A1) is 200 g / mol or more and 2000 g / mol or less. This allows for the creation of a white adhesive with excellent oxygen barrier properties. The molecular weight is calculated from the obtained hydroxyl value and the number of functional groups of hydroxyl groups in the design.

[0022] The hydroxyl value of the polyester polyol (A1) is preferably 20 mg KOH / g or more and 250 mg KOH / g or less. If the hydroxyl value is less than 20 mg KOH / g, the molecular weight is too large, resulting in a high viscosity of the polyol composition (X), which requires a higher coating temperature for application as a solvent-free adhesive, for example. If the hydroxyl value exceeds 250 mg KOH / g, the crosslinking density of the cured coating film becomes too high, which may reduce the adhesive strength.

[0023] When the polyester polyol (A1) has acidic groups, the acid value is preferably 200 mg KOH / g or less. If the acid value exceeds 200 mg KOH / g, the reaction between the polyol composition (X) and the polyisocyanate composition (Y) may proceed too quickly, potentially reducing the coating suitability. There is no particular lower limit to the acid value, but as an example, it is 20 mg KOH / g or more. When the acid value is 20 mg KOH / g or more, good gas barrier properties and initial cohesive force can be obtained due to intermolecular interactions. The hydroxyl value of the polyester polyol (A1) can be measured using the hydroxyl value measurement method described in JIS-K0070, and the acid value can be measured using the acid value measurement method described in JIS-K0070.

[0024] Polyester polyol (A1) may also be polyester polyurethane polyol obtained by extending polyester polyols (A1-1) to (A1-3) with a diisocyanate compound. Since the urethane-extended polyester polyol contains molecular weight components above a certain level and urethane bonds, it has excellent gas barrier properties, excellent initial cohesive strength, and is excellent as an adhesive for lamination.

[0025] Polyol compound (A) may contain substances other than polyester polyol (A1). Examples of polyol compounds other than polyester polyol (A1) include polyester polyols other than polyester polyol (A1), polyether polyols, polyurethane polyols, vegetable oil polyols, sugar alcohols, etc. The content of these polyol compounds (A2) is preferably 50% by mass or less, and more preferably 20% by mass or less, of the total amount of polyol compound (A). Polyol compound (A) may not contain polyol compound (A2).

[0026] (White Pigment (B)) Examples of white pigment (B) include titanium dioxide, zinc oxide, zinc sulfide, barium sulfate, calcium carbonate, chromium oxide, silica, lithopone, antimony white, gypsum, and kaolinite, and one or more of these can be used in combination. It is also preferable that the white pigment be treated with silica and / or alumina. Titanium dioxide or zinc oxide is preferred because of its good dispersibility in polyester polyol (A1).

[0027] The average particle diameter of the white pigment (B) is preferably 100 nm or more and 1000 nm or less, and more preferably 100 nm or more and 500 nm or less. The average particle diameter of the white pigment (B) is obtained by measuring it with a transmission electron microscope or a scanning electron microscope and calculating the volume average diameter.

[0028] The content of the white pigment (B) can be adjusted as appropriate, but from the viewpoint of balancing the coating suitability of the adhesive, the opacity provided by the white pigment (B), and the storage stability of the polyol composition (X), it is preferably 30% by mass or more, preferably 40% by mass or more, preferably 80% by mass or less, and preferably 75% by mass or less of the solid content of the polyol composition (X).

[0029] The white pigment (B) is dispersed in the polyol composition (X) using a disperser. Examples of dispersers include, but are not limited to, roller mills, ball mills, pebble mills, attritors, sand mills, bead mills, and three-roll mills. If the polyol composition (X) contains air bubbles or unexpectedly large particles, it is preferable to remove them by filtration or the like. Conventional known filters can be used.

[0030] (Co-resin (D)) The polyol composition (X) may also preferably contain a co-resin (D) having a functional group having affinity for the white pigment (B) and a resin portion having affinity for polyester polyol (A1) or the organic solvent described later. Examples of functional groups having affinity for the white pigment (B) include acidic functional groups such as carboxyl groups, phosphate groups, and sulfonic acid groups, and basic functional groups such as primary amino groups, secondary amino groups, tertiary amino groups, quaternary ammonium bases, and nitrogen-containing heterocycles. Basic functional groups are preferred.

[0031] The resin portion can be made from polyurethane, polyacrylates and other polycarboxylic acid esters, unsaturated polyamides, polycarboxylic acids, polycarboxylic acid (partial)amine salts, polycarboxylic acid ammonium salts, polycarboxylic acid alkylamine salts, polysiloxanes, long-chain polyaminoamide phosphates, hydroxyl group-containing polycarboxylic acid esters, modified versions thereof, oily dispersants such as amides and salts formed by the reaction of poly(lower alkyleneimines) with polyesters having free carboxyl groups, water-soluble resins and water-soluble polymer compounds such as (meth)acrylic acid-styrene copolymers, (meth)acrylic acid-(meth)acrylic acid ester copolymers, styrene-maleic acid copolymers, polyvinyl alcohol, polyvinylpyrrolidone, polyester-based materials, modified polyacrylate-based materials, ethylene oxide / propylene oxide adduct compounds, phosphate ester-based materials, etc., and can be used individually or in combination of two or more, but is not necessarily limited to these.

[0032] The auxiliary resin (D) may have a comb-like structure in which a resin portion is attached as a side chain to a main chain to which a functional group having affinity for the white pigment (B) is attached; or it may have a linear resin portion with a functional group having affinity for the white pigment (B) attached to one end; or it may have a linear resin portion to which a functional group having affinity for the white pigment (B) is locally attached.

[0033] The content of the auxiliary resin (D) is adjusted as appropriate, but as an example, it is 0.01% by mass or more and 5% by mass or less relative to the white pigment (B), preferably 0.05% by mass or more and 4% by mass or less.

[0034] (Polyisocyanate composition (Y)) (Isocyanate compound (C))

[0035] The isocyanate compound (C) can be any conventionally known compound without particular limitation, including aromatic diisocyanates, aromatic aliphatic diisocyanates, aliphatic diisocyanates, alicyclic diisocyanates, and biuret, nurate, adduct, allophanate, carbodiimide modified, uretdione modified, iminooxadiazinedione, polyurethane polyisocyanates, etc., and can be used individually or in combination of two or more.

[0036] Examples of aromatic diisocyanates include 2,2'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate (also known as MDI), polymethylene polyphenyl polyisocyanate (also called polymeric MDI or crude MDI), 1,3-phenylenediisocyanate, 4,4'-diphenyl diisocyanate, 1,4-phenylenediisocyanate (also known as PPDI), and 2,4-toluene. Examples include, but are not limited to, diisocyanates, 2,6-toluene diisocyanate, 4,4'-toluidine diisocyanate, 2,4,6-triisocyanate toluene, 1,3,5-triisocyanate benzene, toidine diisocyanate (also known as TODI), dianisidine diisocyanate, naphthalene diisocyanate (also known as NDI), 4,4'-diphenyl ether diisocyanate, and 4,4',4''-triphenylmethane triisocyanate.

[0037] Aromatic aliphatic diisocyanates refer to aliphatic isocyanates having one or more aromatic rings in their molecule, and include, but are not limited to, m- or p-xylylene diisocyanate (also known as XDI) and α,α,α',α'-tetramethylxylylene diisocyanate (also known as TMXDI).

[0038] Examples of aliphatic diisocyanates include, but are not limited to, trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate (also known as HDI), pentamethylene diisocyanate (also known as PDI), 1,2-propylene diisocyanate, 2,3-butylene diisocyanate, 1,3-butylene diisocyanate, dodecamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, lysine diisocyanate (also known as LDI), etc.

[0039] Examples of alicyclic diisocyanates include, but are not limited to, 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'-methylenebiscyclohexyl isocyanate (also known as hydrogenated MDI or HMDI), 1,3-bis(isocyanatomethyl)cyclohexane (also known as hydrogenated XDI or HXDI), hydrogenated TMXDI, norbornane diisocyanate (also known as NBDI), etc.

[0040] Examples of the compounds used for synthesizing the adduct include low molecular weight active hydrogen compounds such as ethylene glycol, propylene glycol, metaxylylene alcohol, 1,3-bis(hydroxyethyl)benzene, 1,4-bis(hydroxyethyl)benzene, trimethylolpropane, glycerol, pentaerythritol, erythritol, sorbitol, ethylenediamine, monoethanolamine, diethanolamine, triethanolamine, metaxylylenediamine, etc.

[0041] Compounds used in the synthesis of polyurethane polyisocyanates include alkylene oxide adducts of the low molecular weight active hydrogen compounds mentioned above, various polyester resins, and high molecular weight active hydrogen compounds of polyamides, and can be used individually or in combination of two or more. Preferred compounds include at least one selected from polyester polyols (A1-1) to (A1-3), and diols with a molecular weight of 65 to 300.

[0042] As the diol having a molecular weight of 65 or more and 300 or less, 1,2-propanediol, neopentyl glycol, 2-butyl-2-ethyl-1,3-propanediol, 1,3-butanediol, 2-methyl-1,3-butanediol, 2-ethyl-1,3-butanediol, 2-propyl-1,3-butanediol, 2-butyl-1,3-butanediol, 2-pentyl-1,3-butanediol, 2-(1-methylethyl)-1,3-butanediol, 2,2-dimethyl-1,3-butanediol, 2,3-dimethyl-1,3-butanediol, 2-ethyl-2-methyl-1,3-butanediol, 3-methyl-1,3-butanediol, 1,2-pentanediol, 1,3-pentanediol, 2,4-pentanediol, 2-methyl-1,3-pentanediol, 2-ethyl-1,3-propanediol, 2-propyl-1,3-propanediol, 4-methyl 1,3-pentanediol, 2,4-dimethyl-1,3-pentanediol, 2,2,4-trimethyl-1,3-pentanediol, 2-methyl-2,4-pentanediol, 3-methyl-2,4-pentanediol, 3-ethyl-2,4-pentanediol, 1,2-hexanediol, 1,3-hexanediol, 2-methyl-1,3-hexanediol, 2-ethyl-1,3-hexanediol, 4-methyl-1,3-hexanediol, 5-methyl-1,3-hexanediol, 2,4-hexanediol, 1,3-heptanediol, 2-methyl-1,3-methyl-heptanediol, 4-methyl-1,3-heptanediol, 5-methyl-1,3-heptanediol, 6-methyl-1,3-heptanediol, 2,4-heptanediol, 2,4-octanediol, 3,5-octanediol, 2,4-nonanediol, 3,5-nonanediol, 4,6-nonanediol, etc., diols having an alkyl side chain with 1 to 4 carbon atoms, and

[0043] Diols having an ether linkage, such as diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, dipropylene glycol, trippropylene glycol, tetrapropylene glycol, polypropylene glycol, 4-methoxy-1,3-butanediol, 5-methoxy-1,3-pentanediol, and 5-ethoxy-1,3-pentanediol, are preferably used.

[0044] It is more preferable to use isocyanate compounds having a skeleton derived from xylylene diisocyanate, hydrogenated xylylene diisocyanate, toluene diisocyanate, or diphenylmethane diisocyanate, as these provide good gas barrier properties.

[0045] It is also preferable that the isocyanate compound (C) has a diisocyanate monomer content reduced to 1.0% by mass or less, more preferably to 0.1% by mass or less. In particular, when an aromatic diisocyanate other than diphenylmethane diisocyanate is used as the isocyanate compound (C), it is also preferable that the content of the aromatic diisocyanate is reduced to 1.0% by mass or less, more preferably to 0.1% by mass or less.

[0046] When manufacturing laminates for food packaging using a two-component curing adhesive containing aromatic diisocyanates, unreacted aromatic isocyanate monomers may remain in the adhesive layer. These isocyanate monomers react with surrounding water to form primary aromatic amines (PAAs), which may migrate through the film and leach into the contents (food). PAAs are a cause for concern due to their potential harmful effects on human health, and various regulations have been established, including the European Commission's regulations on plastic materials and products for food contact, which set detection limits for PAAs.

[0047] Since PAA reacts with unreacted aromatic isocyanates in the surrounding environment, the concentration of PAA gradually decreases even if aromatic isocyanates remain in the adhesive layer. Eventually, it will fall below the detection limit, but from the viewpoint of manufacturing efficiency for laminates used in food packaging, it is preferable to have a low initial value of aromatic isocyanate monomers remaining in the adhesive layer. By removing diisocyanate monomers in advance, a two-component curing adhesive with excellent manufacturing efficiency can be produced.

[0048] The diisocyanate monomer can be removed by distilling it under reduced pressure using a short-pass distillation apparatus or a thin-film distillation apparatus. The degree of reduced pressure and distillation temperature are adjusted as appropriate depending on the diisocyanate monomer to be removed, but as an example, they are 0.1 mbar or less and 120°C to 190°C. The diisocyanate monomer removal process may be performed multiple times.

[0049] (Additive (E)) The adhesive of the present invention may contain additive (E) to the extent that it does not impair the adhesive properties and gas barrier properties. Additive (E) may be included in either or both of the polyol composition (X) and the polyisocyanate composition (Y), or it may be prepared separately and mixed with the polyol composition (X) and the polyisocyanate composition (Y) immediately before application of the adhesive. The components will be described below.

[0050] (Urethane catalyst (E1)) Examples of urethane catalyst (E1) include metal catalysts, amine catalysts, aliphatic cyclic amide compounds, and quaternary ammonium salts.

[0051] Examples of metal catalysts include metal complex catalysts, inorganic metal catalysts, and organometallic catalysts. Examples of metal complex catalysts 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.

[0052] Examples of inorganic metal catalysts include those selected from Sn, Fe, Mn, Cu, Zr, Th, Ti, Al, Co, and the like.

[0053] Examples of organometallic catalysts include organozinc compounds such as zinc octoate, zinc neodecanoate, and zinc naphthenate; organotin compounds such as stanus diacetate, stanus dioctoate, stanus dioleate, stanus dilaurate, dibutyltin diacetate, dibutyltin dilaurate, dioctyltin dilaurate, dibutyltin oxide, and dibutyltin dichloride; organonickel compounds such as nickel octoate and nickel naphthenate; organocobalt compounds such as cobalt octoate and cobalt naphthenate; organobismuth compounds such as bismuth octoate, bismuth neodecanoate, and bismuth naphthenate; tetraisopropyloxytitanate, dibutyltitanium dichloride, tetrabutyltitanium trichloride, butoxytitanium trichloride; aliphatic diketones; aromatic diketones; and titanium compounds such as titanium chelate complexes with at least one alcohol having 2 to 10 carbon atoms as a ligand.

[0054] Amine-based 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)isopropanediamine Lopanolamine, 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 Examples include 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, and 1-(2-hydroxypropyl)-2-methylimidazole.

[0055] Examples of aliphatic cyclic amide compounds include δ-valerolactam, ε-caprolactam, ω-enanthollactam, η-capryllactam, and β-propiolactam. Among these, ε-caprolactam is more effective in accelerating curing.

[0056] Examples of quaternary ammonium salts include alkylammonium, aromatic ammonium, hydroxy salts, alkylates, and halide salts. Examples include, but are not limited to, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, benzyltrimethylammonium hydroxide, tetrabutylammonium fluoride, tetrabutylammonium chloride, tetrabutylammonium bromide, tetrabutylammonium iodide, benzyltriethylammonium chloride, and hexadecyltrimethylammonium bromide.

[0057] (Curing aid (E2)) When a polyester polyol (A1) in which some of the hydroxyl groups are modified with acid groups is used as the polyol compound (A), the polyisocyanate composition (Y) may contain an epoxy compound in addition to the isocyanate compound (C). Examples of epoxy compounds include diglycidyl ether of bisphenol A and its oligomer, diglycidyl ether of hydrogenated bisphenol A and its oligomer, diglycidyl orthophthalate, diglycidyl isophthalate, diglycidyl terephthalate, diglycidyl p-oxybenzoate, diglycidyl tetrahydrophthalate, diglycidyl hexahydrophthalate, diglycidyl succinate, diglycidyl adipic acid, diglycidyl sebacate, ethylene glycol diglycidyl ether, and propylene glycol diglycidyl Examples include ethers, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether and polyalkylene glycol diglycidyl ethers, trimellitic acid triglycidyl ester, triglycidyl isocyanurate, 1,4-diglycidyloxybenzene, diglycidylpropylene urea, glycerol triglycidyl ether, trimethylolethane triglycidyl ether, trimethylolpropane triglycidyl ether, pentaerythritol tetraglycidyl ether, and triglycidyl ethers of glycerol alkylene oxide adducts.

[0058] When using epoxy compounds, a commonly known epoxy curing accelerator may be added as appropriate to accelerate curing, provided that the objectives of the present invention are not impaired.

[0059] When polyester polyols (A1-3) are used as the polyol compound (A), known polymerization catalysts can be used in combination to promote the polymerization of carbon-carbon double bonds, and transition metal complexes are one example. The transition metal complex is not particularly limited as long as it is a compound that has the ability to oxidize and polymerize polymerizable double bonds. For example, salts of metals such as cobalt, manganese, lead, calcium, cerium, zirconium, zinc, iron, and copper with octic acid, naphthenic acid, neodecanoic acid, stearic acid, resin acid, tall oil fatty acid, tung oil fatty acid, linseed oil fatty acid, soybean oil fatty acid, etc. can be used. The amount of transition metal complex added is preferably 0 to 10 parts by mass, more preferably 0 to 3 parts by mass, relative to the resin solids contained in the polyol composition (X).

[0060] When using polyester polyols (A1-3) as the polyol compound (A), active energy rays can be used as a method to react the polymerizable carbon-carbon double bond. Known techniques can be used as active energy rays, and curing can be achieved by irradiation with electron beams, ultraviolet rays, or ionizing radiation such as gamma rays. When curing with ultraviolet rays, known ultraviolet irradiation devices equipped with high-pressure mercury lamps, excimer lamps, metal halide lamps, etc., can be used.

[0061] When curing by irradiation with ultraviolet light, a photoinitiator that generates radicals etc. upon irradiation with ultraviolet light may be added in an amount of about 0.1 to 20 parts by mass per 100 parts by mass of polyester polyol (A1-3).

[0062] Radical-generating photoinitiators include hydrogen abstraction types such as benzyl, benzophenone, Michlar's ketone, 2-chlorothioxanthone, and 2,4-diethylthioxanthone, and photocleavage types such as benzoin ethyl ether, diethoxyacetophenone, benzyl methyl ketal, hydroxycyclohexyl phenyl ketone, and 2-hydroxy-2-methyl phenyl ketone. These can be used individually or in combination.

[0063] (Coupling agent (E3)) Examples of coupling agents (E3) include silane coupling agents, titanate coupling agents, and aluminum coupling agents.

[0064] Examples of silane coupling agents include aminosilanes such as γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, N-β(aminoethyl)-γ-aminopropyltrimethoxysilane, N-β(aminoethyl)-γ-aminopropyltrimethyldimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, bis[3-(trimethoxysilyl)propyl]amine, and bis[3-(triethoxysilyl)propyl]amine; 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; and hexamethyldisilazane and γ-mercaptopropyltrimethoxysilane.

[0065] Examples of titanate-based coupling agents include tetraisopropoxytitanium, tetra-n-butoxytitanium, butyl titanate dimer, tetrastearyl titanate, titanium acetylacetonate, titanium lactate, tetraoctylene glycol titanate, titanium lactate, and tetrastearoxititanium.

[0066] Examples of aluminum-based coupling agents include acetalkoxyaluminum diisopropylate.

[0067] (Acid anhydrides (E4)) Examples of acid anhydrides include cyclic aliphatic acid anhydrides, aromatic acid anhydrides, unsaturated carboxylic acid anhydrides, etc., and one or more can be used in combination. More specifically, for example, maleic anhydride, phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, benzophenonetetracarboxylic anhydride, dodecenyl succinic anhydride, polyadipic anhydride, polyazelaic anhydride, polysebacic anhydride, poly(ethyloctadecanediic acid) anhydride, poly(phenylhexadecanedioic acid) anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, hexahydrophthalic anhydride, methylhymic anhydride, trialkyltetrahydrophthalic acid Examples include anhydrides, methylcyclohexenedicarboxylic acid anhydride, methylcyclohexenetetracarboxylic acid anhydride, ethylene glycol bistrimellitate dianhydride, hetic acid anhydride, nadic acid anhydride, methylnadic acid 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-naphthalenesuccinic acid dianhydride, 1-methyl-dicarboxy-1,2,3,4-tetrahydro-1-naphthalenesuccinic acid dianhydride, and the like.

[0068] As the acid anhydride, the above-mentioned compounds modified with glycol may be used. Examples of glycols that can be used for modification include alkylene glycols such as ethylene glycol, propylene glycol, and neopentyl glycol; and polyether glycols such as polyethylene glycol, polypropylene glycol, and butyltetramethylene ether glycol. Furthermore, copolymer polyether glycols of two or more of these glycols and / or polyether glycols can also be used.

[0069] Alternatively, as the acid anhydride, a homopolymer or copolymer of a compound having a polymerizable unsaturated group, such as maleic anhydride, from among the compounds mentioned above may be used. Compounds that can copolymerize with a compound having an acid anhydride group and a polymerizable unsaturated group include α-olefins such as ethylene, propylene, 1,3-butadiene, and cyclopentylethylene; vinyl compounds having an aromatic ring such as styrene, 1-ethynyl-4-methylbenzene, divinylbenzene, 1-ethynyl-4-methylethylbenzene, benzonitrile, acrylonitrile, ptert-butylstyrene, 4-vinylbiphenyl, 4-ethynylbenzyl alcohol, 2-ethynylnaphthalene, and phenanthrene-9-ethynyl; and fluoroolefins such as vinylidene fluoride, tetrafluoroethylene, hexafluoropropylene, and chlorotrifluoroethylene. These can be used individually or in combination of two or more. It is preferable to use styrene and p-tert-butylstyrene, which are vinyl compounds having an aromatic ring.

[0070] (Phosphoric Acid Derivatives (E5)) Examples of phosphate derivatives include phosphoric acid, pyrophosphate, triphosphate, 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, polyoxyethylene alkyl ether phosphate, etc. Phosphoric acid, pyrophosphate, triphosphate, and butyl acid phosphate are preferred.

[0071] The amount of phosphoric acid derivative (E5) blended is preferably 0.005 to 10% by mass of the total solid content of the adhesive, and more preferably 0.01 to 1% by mass.

[0072] (Plasticizer (E6)) Examples of plasticizers (E6) include phthalate-based plasticizers, fatty acid-based plasticizers, aromatic polycarboxylic acid-based plasticizers, phosphate-based plasticizers, polyol-based plasticizers, epoxy-based plasticizers, polyester-based plasticizers, and carbonate-based plasticizers.

[0073] Examples of phthalate-based plasticizers include phthalate 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, butylbenzyl phthalate, dicyclohexyl phthalate, octyldecyl phthalate, dimethyl isophthalate, di-(2-ethylhexyl) isophthalate, and diisooctyl isophthalate, as well as tetrahydrophthalate ester plasticizers such as di-(2-ethylhexyl)tetrahydrophthalate, di-n-octyltetrahydrophthalate, and diisodecyltetrahydrophthalate.

[0074] Examples of fatty acid-based plasticizers include adipic acid-based plasticizers such as di-n-butyl adipate, di-(2-ethylhexyl) adipate, diisodecyl adipate, diisononyl adipate, di(C6-C10 alkyl) adipate, and dibutyldiglycol adipate; azelaic acid-based plasticizers such as di-n-hexyl azelate, di-(2-ethylhexyl) azelate, and diisooctyl azelate; and di-n-butyl sebacate, di-(2 Sebacate-based plasticizers such as -ethylhexyl) sebacate and diisononyl sebacate; maleic acid-based plasticizers such as dimethyl maleate, diethyl maleate, di-n-butyl maleate, and di-(2-ethylhexyl) maleate; fumaric acid-based plasticizers such as di-n-butyl fumarate and di-(2-ethylhexyl) fumarate; monomethyl itaconate, monobutyl itaconate, dimethyl itaconate, diethyl itaconate, dibutyrate Examples include itaconic acid-based plasticizers such as ruitaconate 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; citrate-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 methylacetyl ricinoleate, butylacetyl ricinoleate, glyceryl monoricinoleate, and diethylene glycol monoricinoleate; and other fatty acid-based plasticizers such as diethylene glycol monolaurate, diethylene glycol diperargonate, and pentaerythritol fatty acid esters.

[0075] 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, as well as pyromellitic acid plasticizers such as tetra-(2-ethylhexyl) pyromelitate and tetra-n-octyl pyromelitate.

[0076] Examples of phosphate-based plasticizers include triethyl phosphate, tributyl phosphate, tri-(2-ethylhexyl) phosphate, tributoxyethyl phosphate, triphenyl phosphate, octyldiphenyl phosphate, cresyldiphenyl phosphate, cresylphenyl phosphate, tricresyl phosphate, trixylenyl phosphate, tris(chloroethyl) phosphate, tris(chloropropyl) phosphate, tris(dichloropropyl) phosphate, and tris(isopropylphenyl) phosphate.

[0077] Examples of polyol-based plasticizers include glycol-based plasticizers such as diethylene glycol dibenzoate, dipropylene glycol dibenzoate, triethylene glycol dibenzoate, triethylene glycol di-(2-ethyl butyrate), triethylene glycol di-(2-ethylhexoate), and dibutylmethylene bisthioglycolate, as well as glycerin-based plasticizers such as glycerol monoacetate and glycerol tributyrate.

[0078] Examples of epoxy plasticizers include epoxidized soybean oil, epoxybutyl stearate, di-2-ethylhexyl epoxyhexahydrophthalate, diisodecyl epoxyhexahydrophthalate, epoxy triglycerides, octyl epoxidized oleate, and decyl epoxidized oleate.

[0079] Examples of polyester-based plasticizers include adipic acid-based polyesters, sebaciate-based polyesters, and phthalate-based polyesters.

[0080] Examples of carbonate-based plasticizers include propylene carbonate and ethylene carbonate.

[0081] Other examples of plasticizers include partially hydrogenated terphenyl, adhesive plasticizers, and polymerizable plasticizers such as diallyl phthalate, acrylic monomers, and oligomers. These plasticizers can be used individually or in combination of two or more.

[0082] The amount of plasticizer (E6) can be adjusted as appropriate depending on the desired viscosity, but as an example, it is preferable to keep it to 30% by mass or less of the solid content of the polyisocyanate composition (X).

[0083] (Drying aid (E7)) Drying aid (E7) has the function of promoting the volatilization of organic solvents. Examples of drying aid (E7) include isosorbide, isomannide, isoidide, triacetin, dibutyl sebacate, bis(2-ethylhexyl) terephthalate, and bis(2-ethylhexyl) adipate. By including drying aid (E7), the organic solvent volatilizes more easily during the drying process of the adhesive described later, and less organic solvent remains in the cured coating film of the adhesive.

[0084] The drying aid (E7) preferably has a hydroxyl group. This allows it to react with the isocyanate compound (C) and be incorporated into the cured coating film. Unlike additives without functional groups, there is no risk of it migrating from the adhesive layer to other layers over time, and it has little effect on the physical properties of the adhesive layer over time. The hydroxyl group of the drying aid (E7) is preferably a secondary hydroxyl group. Because it has lower reactivity with the isocyanate compound (C) compared to a primary hydroxyl group, it can effectively suppress the reaction with the isocyanate compound (C) before the drying process.

[0085] From the viewpoint of effectively suppressing the residue of organic solvents, the amount of drying aid (E7) blended is preferably 0.5% by mass or more, and more preferably 1% by mass or more, of the total solid content of the adhesive. From the viewpoint of the solubility of the drying aid (E7) in the adhesive solution, it is preferably 50% by mass or less, and more preferably 30% by mass or less.

[0086] (Plate-shaped inorganic compound (E8)) Using plate-shaped inorganic compound (E8) is preferable because it improves adhesive strength, gas barrier properties, light shielding properties, etc. Examples of platy inorganic compounds (E8) include hydrated silicates (phyllosilicate minerals, etc.), kaolinite-serpentine clay minerals (haloysite, kaolinite, endelite, dickite, nacrite, etc., antigorite, chrysotile, etc.), pyrophyllite-talc group (pyrophyllite, talc, kerolite, etc.), smectite group clay minerals (montmorillonite, beidelite, nontronite, saponite, hectorite, souconite, stevensite, etc.), vermiculite group clay minerals (vermiculite, etc.), mica or mica group clay minerals (muscovite, phlogopite, etc., margalite, tetrasilicic mica, teniolite, etc.), chlorite group (cuquerite, sudoite, clinochlore, chamosite, nimite, etc.), hydrotalcite, platy barium sulfate, boehmite, and polyaluminum phosphate. These minerals may be natural or synthetic clay minerals. Plate-shaped inorganic compounds can be used individually or in combination of two or more types.

[0087] The plate-like inorganic compound (E8) may be ionic, having an interlayer charge, or nonionic, having no interlayer charge. The presence or absence of interlayer charge does not directly and significantly affect the gas barrier properties of the adhesive of the present invention. However, ionic plate-like inorganic compounds and inorganic compounds that swell in water have poor dispersibility in organic solvents, and increasing the amount added may thicken the adhesive or make it thixotropic, potentially reducing its coating suitability. For this reason, it is preferable that the plate-like inorganic compound (E8) is nonionic and has no interlayer charge.

[0088] The average particle size of the plate-like inorganic compound (E8) is not particularly limited, but is preferably 0.1 μm or larger, and more preferably 1 μm or larger. If it is smaller than 0.1 μm, the detour path for oxygen molecules will not be long enough, and a sufficient improvement in gas barrier properties cannot be expected. There is no particular upper limit to the average particle size, but if the particle size is too large, defects such as streaks may occur on the coated surface depending on the coating method. For this reason, the average particle size is preferably 100 μm or less, and more preferably 20 μm or less. In this specification, the average particle size of the plate-like inorganic compound (E8) refers to the particle size that appears most frequently when the particle size distribution of the plate-like inorganic compound (E8) is measured using a light scattering measuring device.

[0089] A higher aspect ratio is preferable for improving gas barrier properties due to the labyrinthine effect of oxygen. Specifically, a ratio of 3 or higher is preferred, more preferably 10 or higher, and most preferably 40 or higher.

[0090] The amount of plate-like inorganic compound (E8) is arbitrary, but as an example, when the total solid content mass of the polyol composition (X), polyisocyanate composition (Y), and plate-like inorganic compound (E8) is 100 parts by mass, the amount of plate-like inorganic compound (E8) is 5 to 50 parts by mass.

[0091] (Other Additives (E9)) In addition, the adhesive of the present invention may contain stabilizers (antioxidants, heat stabilizers, UV absorbers, etc.), antistatic agents, lubricants, antiblocking agents, crystal nucleating agents, etc.

[0092] (Form of Adhesive) The adhesive of the present invention may be in either a solvent-type or solvent-free form. In this specification, a solvent-type adhesive refers to a form used in a 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 film, and then bonded to another substrate, a method known as the dry lamination method. Examples of solvents that can be used include toluene, xylene, methylene chloride, tetrahydrofuran, methyl acetate, ethyl acetate, n-propyl acetate, n-butyl acetate, acetone, methyl ethyl ketone (MEK), cyclohexanone, toluene, xylol, n-hexane, and cyclohexane. Either one or both of the polyol composition (X) and the polyisocyanate composition (Y) contain the above-mentioned organic solvent. In the case of a solvent-type adhesive, the solvent used as a reaction medium during the production of the components of the polyol composition (X) or the polyisocyanate composition (Y) may also be used as a diluent during painting.

[0093] A solvent-free adhesive refers to a form used in the so-called non-solvent lamination method, where the adhesive is applied to a substrate and then bonded to another substrate without the step of heating in an oven or the like to evaporate the solvent. Neither the polyol composition (X) nor the polyisocyanate composition (Y) substantially contains the aforementioned organic solvents. If trace amounts of organic solvent remain in the polyol composition (X) or polyisocyanate composition (Y) due to incomplete removal of the components of the polyol composition (X) or polyisocyanate composition (Y) or the organic solvent used as a reaction medium during the manufacturing of their raw materials, it is considered that the adhesive substantially does not contain organic solvents. Furthermore, if the polyol composition (X) contains a low molecular weight alcohol, the low molecular weight alcohol reacts with the polyisocyanate composition (Y) to become part of the coating film, so there is no need to evaporate it after application. Therefore, this form is also treated as a solvent-free adhesive.

[0094] The two-component curing adhesive of the present invention is preferably formulated so that the ratio [NCO] / [isocyanate-reactive functional groups] between the number of moles of isocyanate groups [NCO] contained in the polyisocyanate composition (X) and the number of moles of functional groups that are reactive with isocyanate [isocyanate-reactive functional groups] contained in the isocyanate-reactive composition (Y) is 0.5 to 5.0, more preferably 1.0 to 3.0. This makes it possible to obtain appropriate curing properties without depending on the ambient humidity during coating.

[0095] <Laminate> The laminate of the present invention can be obtained, for example, by a method having a two-component mixing step, in which the adhesive of the present invention (a mixture of polyisocyanate composition (X) and isocyanate reactive composition (Y)) is applied to a first substrate, then a second substrate is laminated onto the applied surface, and the adhesive layer is cured; or by a method having a two-component fractional coating step, in which the polyisocyanate composition (X) and isocyanate reactive composition (Y) are applied separately to a first substrate and a second substrate, and then the first substrate and the second substrate are laminated by bringing the respective applied surfaces into contact and pressing them together, and the adhesive layer is cured. There are no particular restrictions on the substrate used, and it can be appropriately selected according to the application.

[0096] For example, for food packaging, examples 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, BOPE: biaxially oriented polyethylene film), polypropylene film (CPP: unoriented polypropylene film, OPP: biaxially oriented polypropylene film), ethylene vinyl alcohol copolymer, and gas barrier heat-seal films such as polyolefin films, polyvinyl alcohol films, and ethylene-vinyl alcohol copolymer films, which have an olefin-based heat-sealable resin layer on one or both sides of a gas barrier resin such as polyvinyl alcohol.

[0097] Furthermore, it is also preferable to use biomass films, biodegradable films, or recycled plastic films made from materials containing biomass-derived components, biodegradable components, or recycled components. Biomass films, biodegradable films, and recycled plastic films are sold by various companies, and in addition, films certified in each country can be used, such as film sheets listed in the biomass certified product list of the Japan Organic Resources Association, films listed in the Eco Mark certified product list of the Japan Environment Association, and films bearing the symbol mark set by the Japan Bioplastics Association.

[0098] The film may be stretched. A common stretching method involves melting and extruding the resin into a sheet using methods such as extrusion film formation, followed by simultaneous biaxial stretching or sequential biaxial stretching. In the case of sequential biaxial stretching, it is common to first perform longitudinal stretching, followed by transverse stretching. Specifically, a method combining longitudinal stretching using the speed difference between rolls and transverse stretching using a tenter is frequently used.

[0099] Various surface treatments, such as flame treatment or corona discharge treatment, may be applied to the film surface as needed to ensure that an adhesive layer free from defects such as film breakage or repulsion is formed.

[0100] Alternatively, a barrier film containing a gas barrier layer such as polyvinyl alcohol, ethylene-vinyl alcohol copolymer, or vinylidene chloride may be used in combination. By using such a film, a laminate can be made that has barrier properties against water vapor, oxygen, alcohol, inert gases, volatile organic compounds (fragrances), etc.

[0101] As for the paper, any known paper substrate can be used without particular limitation. Specifically, it is manufactured using natural fibers for papermaking such as wood pulp and manufactured on a known paper 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 pulps that have been chemically modified. As for the type of pulp, chemical pulps produced by sulfate pulping, acidic, neutral, and alkaline sulfite pulping, soda salt pulping, etc., as well as gland pulp, chemigland pulp, thermomechanical pulp, etc. can be used. In addition, various commercially available fine papers, coated papers, backing papers, impregnated papers, cardboard, and paperboard can also be used.

[0102] More specific laminate configurations include: (1) Substrate 1 / Adhesive layer 1 / Sealant film (2) Substrate 1 / Adhesive layer 1 / Metal vapor-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) Transparent vapor-deposited stretched film / Adhesive layer 1 / Substrate 1 / Adhesive layer 2 / Sealant film (7) Substrate 1 / Adhesive layer 1 / Metal vapor-deposited stretched film / Adhesive layer 2 / Sealant film (8) Substrate 1 / Adhesive layer 1 / Transparent vapor-deposited stretched film / Adhesive layer 2 / Sealant film (9) Substrate 1 / Adhesive layer 1 / Metal layer / Adhesive layer 2 / Sealant film (10) Substrate 1 / Adhesive layer 1 / Substrate 2 / Adhesive layer 2 / Metal layer / Adhesive layer 3 / Sealant film (11) Examples include, but are not limited to, the base material 1 / adhesive layer 1 / metal layer / adhesive layer 2 / base material 2 / adhesive layer 3 / sealant film, etc.

[0103] Examples of substrates 1 used in configuration (1) include MDOPE film, BOPE film, OPP film, PET film, nylon film, and paper. Alternatively, a substrate 1 coated with a coating for purposes such as improving gas barrier properties or ink receptivity when providing the printing layer described later may be used. Commercially available coated substrate films 1 include K-OPP film, K-PET film, and K-nylon 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, easy-open heat-seal film, and gas-barrier heat-seal film. The printing layer may be provided on the side of the substrate 1 facing the adhesive layer 1 (or, if a coated substrate film 1 is used, on the side of the coating layer facing the adhesive layer 1) or on the side opposite to 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 general printing methods conventionally used for printing on polymer films and paper.

[0104] Examples of substrates 1 used in configurations (2) and (3) include MDOPE film, BOPE film, OPP film, PET film, paper, etc. The adhesive layer 1 is a cured coating of the adhesive of the present invention. Examples of unstretched metal-deposited films include CPP film, LLDPE film, VM-CPP film, VM-LLDPE film, etc., which are gas barrier heat seal films with metal deposition such as aluminum. Examples of stretched metal-deposited films include VM-MDOPE film, VM-BOPE film, VM-OPP film, etc., which are MDOPE film, BOPE film, OPP film with metal deposition such as aluminum. A printed layer may be provided on any surface of the substrate 1 in the same manner as in configuration (1).

[0105] Examples of transparent vapor-deposited stretched films used in configuration (4) include films obtained by vapor-depositing silica or alumina onto MDOPE film, BOPE film, OPP film, PET film, nylon film, etc. Films with a coating applied to the vapor-deposited layer may also be used for purposes such as protecting the inorganic vapor-deposited layer of silica or alumina. An anchor coat layer may be provided between the vapor-deposited layer and the substrate on which the vapor-deposited layer is provided for the purpose of improving the adhesion of the vapor-deposited layer or improving barrier properties. The adhesive layer 1 is a cured coating film of the adhesive of the present invention. Examples of sealant films are the same as those in configuration (1). A printed layer may be provided on the side of the transparent vapor-deposited stretched film that faces the adhesive layer 1 (or, if a film with a coating applied to the inorganic vapor-deposited layer is used, on the side of the coating layer that faces the adhesive layer 1). The method for forming the printed layer is the same as in configuration (1).

[0106] Examples of substrate 1 used in configuration (5) include PET film and paper. Examples of substrate 2 include nylon film. At least one of adhesive layer 1 and adhesive layer 2 is a cured coating film of the adhesive of the present invention. Examples of sealant film are the same as those in configuration (1). A printed layer may be provided on any surface of substrate 1 in the same manner as in configuration (1).

[0107] Examples of transparent vapor-deposited stretched film used in configuration (6) include those similar to those in configuration (4). Examples of substrate 1 used in configuration (6) include PET film and nylon film. At least one of the adhesive layers 1 and 2 is a cured coating film of the adhesive of the present invention. Examples of sealant film include those similar to those in configuration (1). A printing layer may be provided on the side of the transparent vapor-deposited stretched film facing the adhesive layer 1 (or, if a film with a coating applied to an inorganic vapor-deposited layer is used, on the side of the coating layer facing the adhesive layer 1). The method for forming the printing layer is the same as in configuration (1).

[0108] The base material 1 of configuration (7) is the same as that of configurations (2) and (3). Examples of metal vapor-deposited stretched films include VM-MDOPE film, VM-BOPE film, VM-OPP film, and VM-PET film, which are obtained by vapor deposition of aluminum or the like on MDOPE film, BOPE film, OPP film, or PET film. At least one of adhesive layer 1 and adhesive layer 2 is a cured coating film of the adhesive of the present invention. Examples of sealant films are the same as those of configuration (1). A printing layer may be provided on any surface of the base material 1 in the same manner as in configuration (1).

[0109] Examples of the substrate 1 in configuration (8) include PET film and paper. Examples of the transparent vapor-deposited stretched film include those the same as in configuration (4). At least one of the adhesive layers 1 and 2 is a cured coating film of the adhesive of the present invention. Examples of the sealant film include those the same as in configuration (1). A printed layer may be provided on any surface of the substrate 1 in the same manner as in configuration (1).

[0110] Examples of the base material 1 in configuration (9) include PET film and paper. Examples of the metal layer include aluminum foil. At least one of the adhesive layers 1 and 2 is a cured coating film of the adhesive of the present invention. Examples of the sealant film are the same as those in configuration (1). A printed layer may be provided on any surface of the base material 1 in the same manner as in configuration (1).

[0111] Examples of base material 1 in configurations (10) and (11) include PET film and paper. Examples of base material 2 include nylon film. Examples of metal layers include aluminum foil. At least one layer of adhesive layers 1, 2, and 3 is a cured coating film of the adhesive of the present invention. Examples of sealant films are the same as those in configuration (1). A printed layer may be provided on any surface of base material 1 in the same manner as in configuration (1).

[0112] Because the adhesive of the present invention has excellent gas barrier properties, it can be suitably used in the production of laminates of olefin-based films in which the films themselves have low oxygen barrier properties and do not have high barrier layers such as transparent vapor deposition layers or metal vapor deposition layers. More specific configurations include, for example, MDOPE film / adhesive layer / LLDPE film, BOPE film / adhesive layer / LLDPE film, HDPE film / adhesive layer / LLDPE film, MDOPE film / adhesive layer / CPP film, BOPE film / adhesive layer / CPP film, HDPE film / adhesive layer / CPP film, OPP film / adhesive layer / CPP film, OPP film / adhesive layer / LLDPE film, MDOPE film / adhesive layer / MDOPE film / adhesive layer / LLDPE film, HDPE film / adhesive layer / HDPE film / adhesive layer / LLDPE film, BOPE film / adhesive layer / BOPE film / adhesive layer / LLDPE film, and so on.

[0113] When the adhesive of the present invention is solvent-type, the adhesive of the present invention is applied to a film material that will serve as a base material using a roll such as a gravure roll, the organic solvent is evaporated by heating in an oven or the like, and then the other base material is bonded to obtain the laminate of the present invention. It is preferable to perform an aging treatment after lamination. The aging temperature is preferably room temperature to 80°C, and the aging time is preferably 12 to 240 hours.

[0114] When the adhesive of the present invention is solvent-free, the adhesive of the present invention, which has been preheated to about 40°C to 100°C, is applied to the film material that will serve as the base material using a roll such as a gravure roll, and then the other base material is immediately bonded to it to obtain the laminate of the present invention. It is preferable to perform an aging treatment after lamination. The aging temperature is preferably room temperature to 70°C, and the aging time is preferably 6 to 240 hours.

[0115] The amount of adhesive applied should be adjusted as needed. For solvent-based adhesives, for example, the solid content should be 1 g / m². ２ 15g / m or more ２ Preferably 2 g / m ２ 10g / m or more ２Adjust the following: For solvent-free adhesives, the adhesive application amount is, for example, 1 g / m². ２ 10g / m or more ２ The following applies:

[0116] In addition to the above-described configurations (1) to (11), the laminate of the present invention may further include other films or substrates. As other substrates, in addition to the stretched film, unstretched film, and transparent vapor-deposited film described above, porous substrates such as paper, wood, and leather, as described later, may also be used. The adhesive used when bonding the other substrates may be the adhesive of the present invention or not.

[0117] The "other layer" may contain known additives and stabilizers, such as antistatic agents, easy-adhesion coating agents, plasticizers, lubricants, and antioxidants. The "other layer" may also have its surface pretreated by corona treatment, plasma treatment, ozone treatment, chemical treatment, solvent treatment, etc., to improve adhesion when laminated with other materials.

[0118] The laminate of the present invention can be suitably used in a variety of applications, such as packaging materials for food, pharmaceuticals, and household goods; lids; paper tableware such as paper straws, paper napkins, paper spoons, paper plates, and paper cups; protective wall materials; roofing materials; solar panel materials; battery packaging materials; window materials; outdoor flooring materials; lighting protection materials; automotive components; signs; stickers and other outdoor industrial applications; decorative sheets used in injection molding simultaneous decoration methods; and packaging materials for laundry detergents, kitchen detergents, bath detergents, bath soaps, liquid shampoos, liquid conditioners, and the like.

[0119] <Packaging Material> The laminate of the present invention can be used as a multilayer packaging material for the purpose of protecting food, pharmaceuticals, and the like. When used as a multilayer packaging material, the layer configuration may change depending on the contents, usage environment, and usage form. Furthermore, the packaging material of the present invention may be provided with an easy-open treatment or resealing means as appropriate.

[0120] As an example of a specific embodiment of the packaging material of the present invention, a packaging material made by forming a bag from the laminate described above can be mentioned. The laminate is folded or overlapped so that the inner layers (sealant film surfaces) face each other, and the peripheral edges are heat-sealed to form a bag. Methods for forming the bag include heat sealing methods such as side seal type, two-side seal type, three-side seal type, four-side seal type, envelope seal type, gusset seal type, pleated seal type, flat-bottom seal type, square-bottom seal type, gusset type, and other heat-seal types. The packaging material of the present invention can take various forms depending on the contents, usage environment, and usage method. Self-standing packaging materials (standing pouches) are also possible. Known heat sealing methods include bar seal, rotary roll seal, belt seal, impulse seal, high-frequency seal, and ultrasonic seal.

[0121] Products using the packaging material of the present invention are manufactured by filling the packaging material with contents through its opening and then heat-sealing the opening. Examples of contents that can be filled include, for example, food products such as rice crackers, bean snacks, nuts, biscuits / cookies, wafers, marshmallows, pies, semi-baked cakes, candies, and snack foods; staple foods such as bread, instant noodles, dried noodles, pasta, aseptically packaged rice, rice porridge, packaged mochi, and cereal foods; processed agricultural products such as pickles, boiled beans, natto, miso, frozen tofu, tofu, enoki mushrooms, konjac, processed wild vegetables, jams, peanut cream, salads, frozen vegetables, and processed potato products; processed livestock products such as ham, bacon, sausages, processed chicken products, and corned beef; and fish ham. Examples of processed seafood products include sausages, processed seafood products, fish cakes, seaweed, preserved foods, dried bonito flakes, salted seafood, smoked salmon, and spicy cod roe; fruits such as peaches, oranges, pineapples, apples, pears, and cherries; vegetables such as corn, asparagus, mushrooms, onions, carrots, radishes, and potatoes; frozen and chilled prepared foods such as hamburgers, meatballs, fried seafood, dumplings, and croquettes; dairy products such as butter, margarine, cheese, cream, instant creamy powder, and infant formula; liquid seasonings; retort curry; and pet food.

[0122] Furthermore, as a non-food product, it can be used as a packaging material for various items such as cigarettes, disposable hand warmers, pharmaceuticals such as intravenous fluid packs, liquid laundry detergent, liquid dish soap, liquid bath detergent, liquid bath soap, liquid shampoo, liquid conditioner, cosmetics such as lotions and emulsions, vacuum insulation materials, and batteries.

[0123] <Recycled Plastics> The laminates and packaging materials of the present invention can be used as raw materials for recycled plastics. The recycled plastics of the present invention are recycled using the laminates and packaging materials of the present invention as raw materials. The method for recycling the laminates and packaging materials is not particularly limited, and known methods can be used. Examples include crushing the laminates and packaging materials, melting and kneading them, then pelletizing and molding them, or directly feeding the crushed laminates and packaging materials into an extrusion molding machine and melting and kneading them in the heating cylinder of the molding machine to use them as molding raw materials without melting and kneading or pelletizing.

[0124] Laminates and packaging materials can be crushed using known crushers. The crusher is not particularly limited and examples include using a jaw crusher, impact crusher, cutter mill, stamp mill, ring mill, roller mill, jet mill, or hammer mill. The size of the fragments of the printed material or laminate is preferably 1 mm to 40 mm in side length, and more preferably 8 mm to 20 mm.

[0125] It is preferable that the crushed laminates and packaging materials are washed before being subjected to heating and melting. Washing methods include batch or continuous washing, and water, detergent, neutralizing agent, or alkaline aqueous solution may be used. Furthermore, it is preferable that the washed laminates and packaging materials are dehydrated and dried. Centrifugal dehydration is preferred as the dehydration method, and hot air drying is preferred as the drying method.

[0126] Dehydration and drying allow for adjustment of the moisture content of the laminate subjected to heating and melting. This helps to avoid foaming during the production of recycled plastics. If air bubbles occur during pellet production, the pressure in the cylinder changes, causing the extrusion amount and pressure to be inconsistent, which may result in irregular pellet shapes and dimensions. Furthermore, when manufacturing molded products using the produced pellets through secondary molding, surface irregularities are likely to occur, potentially degrading the surface condition of the molded product.

[0127] In one embodiment, dehydration and drying are carried out until the moisture content of the laminate used for the production of recycled plastic is 3% by mass or less, preferably 2% by mass or less, more preferably 1% by mass or less, and even more preferably 0.5% by mass or less, based on the total mass of the laminate.

[0128] The crushed laminates and packaging materials are heated and melted at 120-280°C and then kneaded. The temperature at which the laminates and packaging materials are melted can be adjusted considering the glass transition temperature and melting temperature of the laminates or packaging materials, the shape when pelletized, and the pressure applied during the molding process. The screw rotation speed during kneading is, for example, 50-1000 RPM.

[0129] The laminate and packaging material thus melt-kneaded are cooled and shredded to form pellets. Examples of pelletizing methods include hot-cutting and strand-cutting methods, but are not particularly limited. To prevent foreign matter from being mixed into the pellets, it is preferable to provide a screen mesh at the discharge section of the melt-kneaded laminate and packaging material. Examples of screen meshes include woven types such as plain weave, twill weave, plain tatami weave and twill tatami, and perforated metal types. The size of the screen mesh is preferably 40 mesh or more, more preferably 80 mesh or more, and even more preferably 120 mesh or more, taking into consideration the pressure at the discharge section and clogging. Examples of cooling methods include air cooling, wind cooling, and water cooling. In the present invention, it is preferable to include a water cooling step. It is preferable to cool to 20°C to 80°C, and more preferably to 30°C to 60°C.

[0130] The laminate of the present invention can be used as is in the production of recycled plastics if the multiple base materials constituting the laminate are made of the same type of resin. Alternatively, it may be used in the production of recycled plastics after being immersed in a release agent (for example, an alkaline solution such as an aqueous sodium hydroxide solution) for a certain period of time to separate each layer of the laminate.

[0131] If the multiple substrates constituting the laminate of the present invention are made of different resin types, it is preferable to immerse them in a release agent for a certain period of time to separate each layer of the laminate, and then separate them by resin type for use in the production of recycled plastics. Conventional known release agents can be used.

[0132] The material may be used in the manufacture of recycled plastic after the printed layer has been removed. The printed layer can be removed by known methods. The printed layer itself may be formed using a printing ink that is easily peeled off from the substrate by immersion in a release agent, or a delamination layer may be formed by applying a coating agent containing a resin that is easily peeled off from the substrate by immersion in a release agent between the printed layer and the substrate, and the printed layer may be provided on the delamination layer.

[0133] The recycled plastic of the present invention may contain known additives. Examples of such additives include at least one antioxidant selected from the group consisting of phenolic and phosphorus-based agents; at least one lubricant selected from the group consisting of fatty acid amides, alkylene fatty acid amides, metal soaps, and esters; hindered amine-based weather stabilizers; waxes with an acid value of 5 mg KOH / g or less; and at least one antistatic agent selected from the group consisting of fatty acid sulfons and fatty acid esters.

[0134] 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 added shall be of the same resin type as the base material used in the laminate of the present invention. The virgin plastic may be added when pelletizing the laminate and packaging material of the present invention, or when molding the pelletized recycled plastic of the present invention. It may also be added both when pelletizing and when molding the recycled plastic. As an example, the amount of virgin plastic used in combination when pelletizing the laminate and packaging material of the present invention is in the range of laminate / packaging material:virgin plastic of 100:0 to 25:75 (mass ratio). As an example, the amount of virgin plastic used when molding the pelletized recycled plastic of the present invention is in the range of recycled plastic:virgin plastic of 100:0 to 25:75 (mass ratio).

[0135] 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, automobile parts such as bumpers and interior materials, components for home appliances, containers such as pallets and containers for transport, bottles, hangers, stationery, pots and cups, disposable cutlery, and toys. It can also be recycled as a film, or the recycled film can be molded and used as cushioning material when transporting fruits, etc., but is not limited to these uses. As a method for turning the recycled plastic of the present invention into a film to produce a recycled film, known methods such as T-die molding, inflation molding, solution casting molding, and calendering can be used. As a method for molding the recycled film, known methods such as vacuum forming and hot press molding can be used.

[0136] The present invention will be described in more detail below with reference to specific synthesis examples and embodiments, but the present invention is not limited to these embodiments. In the following examples, "parts" and "%" represent "parts by mass" and "mass%", respectively, unless otherwise specified.

[0137] <Preparation of Polyol Composition (X)> (Synthesis of Polyester Polyol (A1)-1) In a polyester reaction vessel equipped with a stirrer, nitrogen gas inlet tube, Snider tube, and condenser, 20.98 parts of ethylene glycol, 0.12 parts of glycerin, 50.94 parts of 1,3,5-tris(2-hydroxyethyl)isocyanuric acid, and 50.41 parts of phthalic anhydride were charged. The mixture was gradually heated so that the temperature at the top of the rectification tube did not exceed 100°C, and the internal temperature was maintained at 220°C. The esterification reaction was terminated when the acid value became 1 mg KOH / g or less, yielding a polyester polyol with a number average molecular weight of 670. The hydroxyl value was 230.2 mg KOH / g. This was used as Polyester Polyol (A1)-1.

[0138] (Synthesis of Polyester Polyol (A1)-2) In a polyester reaction vessel equipped with a stirrer, nitrogen gas inlet tube, Snider tube, and condenser, 1.26 parts of ethylene glycol, 26.76 parts of glycerin, and 40.99 parts of phthalic anhydride were charged. The mixture was gradually heated so that the temperature at the top of the rectification tube did not exceed 100°C, and the internal temperature was maintained at 190°C. When the acid value reached 40 mg KOH / g, 7.33 parts of phthalic anhydride were added, and the esterification reaction was terminated when the acid value reached 70 mg KOH / g. Polyester polyol (A1)-2 with a number average molecular weight of 2000 was obtained. The hydroxyl value was 165 mg KOH / g.

[0139] (Synthesis of Polyester Polyol (A1)-3) In a polyester reaction vessel equipped with a stirrer, nitrogen gas inlet tube, Snider tube, and condenser, 51.06 parts of ethylene glycol and 63.30 parts of phthalic anhydride were charged, and the mixture was gradually heated so that the temperature at the top of the rectification tube did not exceed 100°C, maintaining the internal temperature at 220°C. The esterification reaction was terminated when the acid value became 1 mg KOH / g or less, and 0.01 parts of phosphoric acid were added to obtain Polyester Polyol (A1)-3 with a number average molecular weight of 340. The hydroxyl value was 331.0 mg KOH / g.

[0140] (Synthesis of Polyester Polyol (A1)-4) In a polyester reaction vessel equipped with a stirrer, nitrogen gas inlet tube, Snider tube, and condenser, 79.10 parts of ethylene glycol, 74.06 parts of phthalic anhydride, 73.07 parts of adipic acid, and 0.01 parts of titanium tetraisopropoxide were charged. The mixture was gradually heated so that the temperature at the top of the rectification tube did not exceed 100°C, and the internal temperature was maintained at 220°C. The esterification reaction was terminated when the acid value became 1 mg KOH / g or less. Further heating to 60°C was followed by the addition of 0.03 parts of phosphoric acid, and the mixture was stirred for 1 hour to obtain Polyester Polyol (A1)-4 with a number average molecular weight of 800. The hydroxyl value was 143.2 mg KOH / g.

[0141] (Synthesis of Polyester Polyol (A1)-5) In a polyester reaction vessel equipped with a stirrer, nitrogen gas inlet tube, Snider tube, and condenser, 35.17 parts of ethylene glycol, 15.40 parts of glycerin, 84.17 parts of phthalic anhydride, and 0.013 parts of titanium tetraisopropoxide were charged. The mixture was gradually heated so that the temperature at the top of the rectification tube did not exceed 100°C, and the internal temperature was maintained at 220°C. The esterification reaction was terminated when the acid value became 1 mg KOH / g or less, yielding Polyester Polyol (A1)-5 with a number average molecular weight of 1050. The hydroxyl value was 190.0 mg KOH / g.

[0142] (Synthesis of polyester polyol (A2)) In a polyester reaction vessel equipped with a stirrer, nitrogen gas inlet tube, Snider tube, and condenser, 41.24 parts of ethylene glycol, 55.18 parts of phthalic anhydride, 13.63 parts of adipic acid, and 0.004 parts of titanium tetraisopropoxide were charged. The mixture was gradually heated so that the temperature at the top of the rectification tube did not exceed 100°C, and the internal temperature was maintained at 220°C. The esterification reaction was terminated when the acid value became 0.5 mg KOH / g or less, yielding a polyester intermediate with a number average molecular weight of 500.

[0143] Next, 71.07 parts of the polyester polyol intermediate with a number average molecular weight of 500 synthesized above, 28.93 parts of isophorone diisocyanate, and 30 parts of ethyl acetate were charged into a four-necked flask equipped with a stirrer, thermometer, reflux condenser, and nitrogen gas inlet tube. The mixture was reacted at 70°C for 20 hours under a nitrogen stream, and then 36.67 parts of ethyl acetate were added to obtain a solution of polyester polyol (A2) with a resin solids content of 60%. The number average molecular weight of polyester polyol (A2) was 9000.

[0144] (Preparation of Polyol Composition (X)) Polyol composition (X-1) was prepared using polyester polyol (A1)-1: 19.95 parts, white pigment (B): 36 parts, dispersant: 5 parts, and ethyl acetate: 22.75 parts. Polyol compositions (X-2) to (X-5) and (X') were prepared by changing the formulation of the polyol compound (A), white pigment (B), co-resin (D), and solvent as shown in Table 1. R-780 (titanium dioxide pigment with an average particle size of 0.24 μm, manufactured by Ishihara Sangyo Co., Ltd.) was used as the white pigment (B). A co-resin having a basic adsorption group was used as the co-resin (D). The values ​​for polyol compound (A), white pigment (B), and co-resin (D) in the table represent the solid content.

[0145]

[0146] <Preparation of Adhesives> The polyol composition (X) and the isocyanate composition (Y) were mixed in the proportions shown in Table 2 to prepare the adhesives for the examples and comparative examples. Takenate D110N (manufactured by Mitsui Chemicals, Inc., XDI-based polyisocyanates, with a non-volatile content of 75%) was used as the isocyanate composition (Y).

[0147] <Manufacturing of Laminate> A 25 μm thick MDOPE film (manufactured by Futamura Chemical Co., Ltd., PE3K-H) is coated with the prepared adhesive, and the cured coating weight is 3.8 g / m². ２ The mixture was coated in this manner, and after the solvent evaporated, it was laminated with a 60 μm thick LLDPE film (manufactured by RM Tohcello Co., Ltd., TUX-HC). The laminate was then aged at 50°C for 3 days to obtain the laminate.

[0148] <Evaluation> (Adhesive Strength)A test piece with a width of 15 mm was cut from the aged laminate, and using a tensile testing machine, the adhesive strength (N / 15 mm) between the MDOP E / LLDPE films was measured by T-peel at a peeling rate of 300 mm / min and evaluated according to the following criteria. The results are summarized in Table 2. A: Adhesive strength is 2.0 N or more B: Adhesive strength is 1.0 N or more and less than 2.0 N C: Adhesive strength is 0.5 N or more and less than 1.0 N D: Adhesive strength is less than 0.5 N

[0149] (Oxygen Permeability) The aged laminate was adjusted to a size of 10 cm × 10 cm, and using an OX-TRAN 2 / 21 (manufactured by Mocon: oxygen permeability measuring device), in accordance with JIS-K7126 (isobaric method), the oxygen permeability was measured under atmospheres of 23°C 0% RH and 90% RH, and evaluated according to the following criteria. The results are summarized in Table 2. Here, RH represents relative humidity. A: Oxygen permeability is less than 50 cc / m ２ / day / atm B: Oxygen permeability is 50 cc / m ２ / day / atm or more and less than 100 cc / m ２ / day / atm C: Oxygen permeability is 100 cc / m ２ / day / atm or more

[0150]

Claims

1. A two-component curing adhesive comprising a polyol composition (X) and a polyisocyanate composition (Y), wherein the polyol composition (X) comprises a polyol compound (A) and a white pigment (B), the polyisocyanate composition (Y) comprises an isocyanate compound (C), and the polyol compound (A) is at least one selected from polyester polyols (A1-1) obtained by polycondensation of a polycarboxylic acid containing an ortho-directing polycarboxylic acid and a polyhydric alcohol, polyester polyols having an isocyanuric ring (A1-2), and polyester polyols having a polymerizable carbon-carbon double bond (A1-3), and includes a polyester polyol (A1) having a molecular weight of 200 g / mol or more and a molecular weight of 2000 g / mol or less.

2. The two-component curing adhesive according to claim 1, wherein the white pigment (B) comprises titanium dioxide or zinc oxide.

3. The two-component curing adhesive according to claim 1, wherein the average particle size of the white pigment (B) is 100 nm or more and 1000 nm or less.

4. The two-component curing adhesive according to claim 1, wherein the content of the white pigment (B) is 30% by mass or more and 80% by mass or less of the solid content of the polyol composition (X).

5. The two-component curable adhesive according to claim 1, wherein the polyol composition (X) comprises a co-resin (D) having a functional group having affinity for the white pigment (B) and a resin portion having affinity for the polyester polyol (A1).

6. The two-component curing adhesive according to claim 5, wherein the content of the auxiliary resin (D) is 0.01% by mass or more and 5% by mass or less of the white pigment (B).

7. The two-component curing adhesive according to claim 1, comprising a plasticizer (E6).

8. The two-component curing adhesive according to claim 1, comprising a drying aid (E7).

9. The two-component curing adhesive according to claim 1, which is solvent-based.

10. A laminate comprising a first substrate, a second substrate, and an adhesive layer for bonding the first substrate and the second substrate, wherein the adhesive layer is a cured coating film of a two-component curing adhesive as described in any one of claims 1 to 9.

11. A packaging material comprising the laminate described in claim 10.

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