Two-part curable adhesive, laminate, and packaging material

Abstract

Provided is an adhesive which is usable as a solventless adhesive and has excellent retort resistance and in which printed layers are less apt to redissolve.　This two-part curable adhesive comprises a polyisocyanate composition (X) including polyisocyanate compounds (A) and an isocyanate-reactive composition (Y) including isocyanate-reactive compounds (B), wherein the polyisocyanate compounds (A) comprise a polyurethane polyisocyanate (A1) that is a product of reaction between a polyether polyol and hexamethylene diisocyanate and a non-aromatic diisocyanate derivative (A2) having 1.8-2.5 functional groups on average and the isocyanate-reactive compounds (B) comprise a polyether polyol (B1) having a molecular weight of 700-2,000 g / mol and an amine compound (B2), the content of polyether polyols of less than 700 g / mol being 30 mass% or less.

Description

Two-component curable adhesive, laminate, and packaging material

[0001] The present invention relates to a two-component curable adhesive, a laminate, and a packaging material.

[0002] Laminates used for various packaging materials, labels, etc. are obtained by laminating various substrates such as various plastic films, metal foils, and papers, and are imparted with design properties, functionality, storage properties, convenience, transport resistance, etc. The packaging material formed by molding the laminate into a bag shape is used as a packaging material for foods, pharmaceuticals, detergents, etc.

[0003] Conventionally, laminates used for packaging materials are mainly obtained by a dry lamination method in which an adhesive dissolved in a volatile organic solvent (sometimes referred to as a solvent-type laminate adhesive) is applied to a substrate, the organic solvent is volatilized in the process of passing through an oven, and another substrate is bonded. However, in recent years, from the viewpoints of reducing environmental impact and improving the working environment, the demand for reaction-type two-component laminate adhesives (hereinafter referred to as solvent-free adhesives) that do not contain volatile organic solvents has been increasing (Patent Document 1).

[0004] Japanese Patent Application Laid-Open No. 2014-159548

[0005] Solvent-free adhesives have many advantages such as no drying process and no solvent discharge, energy saving and low running costs, and no concern about solvent residue in the laminate after bonding plastic films together or in the laminate after bonding a plastic film to a metal foil or a metal vapor deposition layer. On the other hand, the components used in solvent-free adhesives need to be designed with a low molecular weight so that they can have a coating viscosity when heated to about 40°C to 100°C. Therefore, for example, the physical properties of the adhesive layer (cured coating film of the adhesive) formed by a solvent-free adhesive tend to be inferior to those of a solvent-type adhesive, and improvement of the physical properties of solvent-free adhesives is required. More specifically, for example, development of a solvent-free adhesive having physical properties (retort resistance) at a level sufficient for manufacturing a laminate for a food packaging material subjected to retort treatment is required.

[0006] Furthermore, in laminates for packaging materials, a printed layer is generally provided on the back side (contents side) of the outermost substrate (from the perspective of the contents), and the printed layer and other substrates are bonded together with an adhesive. However, some solvent-free adhesives containing low molecular weight compounds can easily redissolve the printed layer.

[0007] The present invention has been made in view of these circumstances, and aims to provide an adhesive that can be used as a solvent-free adhesive, has excellent retort resistance, and is difficult to redissolve the printed layer, as well as a laminate obtained using the adhesive and a packaging material.

[0008] In other words, the present invention relates to a two-component curable adhesive comprising a polyisocyanate composition (X) containing a polyisocyanate compound (A) and an isocyanate-reactive composition (Y) containing an isocyanate-reactive compound (B), wherein the polyisocyanate compound (A) comprises a polyurethane polyisocyanate (A1), which is a reaction product of a polyether polyol and hexamethylene diisocyanate, and a derivative of a non-aromatic diisocyanate (A2) having an average number of functional groups of 1.8 or more and 2.5 or less, and the isocyanate-reactive compound (B) comprises a polyether polyol (B1) with a molecular weight of 700 g / mol or more and 2000 g / mol or less, and an amine compound (B2), and the content of polyether polyol with a molecular weight of less than 700 g / mol in the isocyanate-reactive compound (B) is 30% by mass or less.

[0009] According to the present invention, it is possible to provide an adhesive that can be used as a solvent-free adhesive, has excellent retort resistance, and is difficult to redissolve the printed layer, as well as a laminate obtained using the adhesive and a packaging material.

[0010] <Adhesive> The adhesive of the present invention is a two-component curing type adhesive comprising a polyisocyanate composition (X) containing a polyisocyanate compound (A), and an isocyanate-reactive composition (Y) containing an isocyanate-reactive compound (B) and an amine compound (C).

[0011] (Polyisocyanate composition (X)) Polyisocyanate composition (X) comprises a polyisocyanate compound (A). Polyisocyanate compound (A) comprises a polyurethane polyisocyanate (A1), which is a reaction product of a polyether polyol and hexamethylene diisocyanate, and a derivative of a non-aromatic diisocyanate (A2) having an average number of functional groups of 1.8 or more and 2.5 or less.

[0012] Polyether polyols used in the synthesis of polyurethane polyisocyanate (A1) include those obtained by addition polymerization of alkylene oxides such as ethylene oxide, propylene oxide, butylene oxide, styrene oxide, epichlorohydrin, tetrahydrofuran, and cyclohexylene in the presence of a polymerization initiator.

[0013] Polymerization initiators include glycols such as ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, methylpentanediol, dimethylbutanediol, butylethylpropanediol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, bishydroxyethoxybenzene, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, and triethylene glycol;

[0014] Trifunctional or tetrafunctional aliphatic alcohols such as glycerin, trimethylolpropane, pentaerythritol, and triol compounds of polypropylene glycol;

[0015] Examples include primary or secondary alkylamines such as ethylamine and diethylamine, amine compounds having multiple amino groups such as methylenediamine and ethylenediamine, and amine compounds having active hydrogen groups such as primary or secondary alkanolamines such as monoethanolamine and diethanolamine.

[0016] The molecular weight of the polyether polyol can be adjusted as appropriate, but as an example, it is 100 g / mol to 8000 g / mol. Preferably, it is 100 g / mol to 5000 g / mol, preferably 100 g / mol to 3000 g / mol, preferably 100 g / mol to 1500 g / mol, and preferably 100 g / mol to 700 g / mol. The hydroxyl value of the polyether polyol can be adjusted as appropriate, but as an example, it is preferably 10 mg KOH / g to 1200 mg KOH / g.

[0017] It is preferable to use a bifunctional polyether polyol. It is also preferable to use polypropylene glycol or polyethylene glycol.

[0018] Polyurethane polyisocyanate (A1) is obtained by reacting hexamethylene diisocyanate and a polyether polyol under conditions in which the isocyanate groups of hexamethylene diisocyanate are in excess of the hydroxyl groups of the polyether polyol, and then removing unreacted hexamethylene diisocyanate monomer as needed. The equivalent ratio of isocyanate groups to hydroxyl groups [NCO] / [hydroxyl groups] can be adjusted as appropriate, but as an example, it is between 2.0 and 20.0.

[0019] 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.

[0020] Examples of non-aromatic diisocyanate derivatives (A2) having an average number of functional groups of 1.8 or more and 2.5 or less include the biuret, adduct, allophanate, carbodiimide-modified, nurate, and uretdione-modified forms of non-aromatic diisocyanates. These can be used individually or in combination so that the average number of functional groups is 1.8 or more and 2.5 or less (however, those corresponding to polyurethane polyisocyanate (A1) are not treated as non-aromatic diisocyanate derivatives (A2)). It is preferable to use the biuret, adduct, allophanate, and nurate forms, more preferable to use the biuret, adduct, and allophanate forms, and even more preferable to use the adduct and allophanate forms. Hereinafter, non-aromatic diisocyanate derivatives (A2) having an average number of functional groups of 1.8 or more and 2.5 or less will also be simply referred to as polyisocyanate compounds (A2).

[0021] Non-aromatic diisocyanates include aliphatic diisocyanates (aliphatic isocyanates having one or more aromatic rings in the molecule) such as m- or p-xylylene diisocyanate (also known as XDI), α,α,α',α'-tetramethylxylylene diisocyanate (also known as TMXDI), 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, and lysine diisocyanate (also known as LDI). Examples include alicyclic diisocyanates such as cyanates, 3-isocyanate methyl-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(isocyanate methyl)cyclohexane (also known as hydrogenated XDI or HXDI), norbornane diisocyanate (also known as NBDI), etc., which can be used individually or in combination.

[0022] Examples of polyols used in the synthesis of adducts 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; bisphenols such as bisphenol A, bisphenol F, hydrogenated bisphenol A, and hydrogenated bisphenol F; and dimerols.

[0023] Polyether polyols obtained by addition polymerization of alkylene oxides such as ethylene oxide, propylene oxide, butylene oxide, styrene oxide, epichlorohydrin, tetrahydrofuran, and cyclohexylene using the aforementioned glycol as a polymerization initiator; polyether urethane polyols obtained by further increasing the molecular weight of the polyether polyol with an isocyanate compound;

[0024] Polyester polyol (1) is a reaction product of a polyester obtained by a ring-opening polymerization reaction of a cyclic ester compound such as propiolactone, butyrolactone, ε-caprolactone, σ-valerolactone, or β-methyl-σ-valerolactone with the glycol; Polyester polyol (2) is obtained by reacting a difunctional polyol such as the glycol, dimerol, or bisphenol with a difunctional carboxylic acid:

[0025] Examples include polyurethane polyols obtained by reacting a difunctional polyol such as the glycol, dimer ol, or bisphenol with a difunctional isocyanate; polyether urethane polyols obtained by further increasing the molecular weight of the polyether polyol with an isocyanate compound; and polyester polyurethane polyols obtained by reacting polyester polyols (1) to (2) with a difunctional isocyanate.

[0026] The difunctional carboxylic acids used in the synthesis of polyester polyols (2) include aromatic polybasic 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 acid anhydride, naphthalic acid, biphenyldicarboxylic acid, 1,2-bis(phenoxy)ethane-p,p'-dicarboxylic acid, 5-sodium sulfisoisophthalic acid, tetrachlorophthalic anhydride, and tetrabromophthalic anhydride; and methyl esters of aromatic polybasic acids such as dimethylterephthalic acid and dimethyl 2,6-naphthalenedicarboxylic acid;

[0027] Aliphatic polybasic acids such as malonic acid, succinic acid, succinic anhydride, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, fumaric acid, maleic acid, maleic anhydride, and itaconic acid; alkyl esters of aliphatic polybasic acids such as dimethyl malonate, diethyl malonate, dimethyl succinate, dimethyl glutarate, dimethyl adipic acid, diethyl pimelate, diethyl sebacate, dimethyl fumarate, diethyl fumarate, dimethyl maleate, and diethyl maleate;

[0028] Examples include 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, hymic anhydride, hettic anhydride, and other alicyclic polybasic acids; these can be used individually or in combination of two or more.

[0029] In the synthesis of polyurethane polyols, non-aromatic diisocyanates or their derivatives are preferably used as the bifunctional isocyanates.

[0030] The molecular weight of the polyol used in the synthesis of the adduct can be adjusted as appropriate, but one example is between 50 g / mol and 4000 g / mol.

[0031] The adduct is obtained by reacting a non-aromatic diisocyanate with a polyol under conditions in which the isocyanate groups of the isocyanate are in excess of the hydroxyl groups of the polyol, and then removing unreacted diisocyanate monomers as needed. The equivalent ratio of isocyanate groups to hydroxyl groups [NCO] / [hydroxyl groups] can be adjusted as appropriate, but as an example, it is between 2.0 and 20.0. The removal of the diisocyanate monomer can be carried out using the same method as in the synthesis of polyurethane polyisocyanate (A1).

[0032] The proportion of polyurethane polyisocyanate (A1) to the total amount of polyurethane polyisocyanate (A1) and polyisocyanate compound (A2) is preferably 10% by mass or more and 90% by mass or less. More preferably, the proportion of polyurethane polyisocyanate (A1) to the total amount of polyurethane polyisocyanate (A1) and polyisocyanate compound (A2) is 70% by mass or less.

[0033] The polyisocyanate composition (X) may contain a polyisocyanate compound (A3) other than polyurethane polyisocyanate (A1) and polyisocyanate compound (A2). Examples of polyisocyanate compounds (A3) include polyisocyanate compounds derived from aromatic diisocyanates. The content of polyisocyanate compound (A3) is preferably 10% by mass or less of polyisocyanate compound (A), in other words, the total amount of polyurethane polyisocyanate (A1) and polyisocyanate compound (A2) in polyisocyanate compound (A) is preferably 90% by mass or more. The total amount of polyurethane polyisocyanate (A1) and polyisocyanate compound (A2) in polyisocyanate compound (A) may be 95% by mass or more, and may be 98% by mass or more. Polyisocyanate compound (A) does not necessarily have to contain polyisocyanate compound (A3).

[0034] The polyisocyanate composition (X) used in the present invention may contain diisocyanate monomers, i.e., non-aromatic diisocyanates exemplified as raw materials for the polyisocyanate compound (A2), or diisocyanate monomers such as aromatic diisocyanates like toluene diisocyanate and diphenylmethane diisocyanate. Diisocyanate monomers are a concern due to their harmful effects on the human body, and from the viewpoint of occupational safety and health, their content is preferably 5% by mass or less, preferably 1% by mass or less, preferably 0.5% by mass or less, and preferably reduced to 0.1% by mass or less of the polyisocyanate composition (X).

[0035] From the perspective of occupational safety and health, there is a movement to regulate the use of isocyanate monomers, and the European Commission has adopted the REACH regulation, which prohibits the market placement of products containing 0.1% by mass or more of isocyanate monomers if certain requirements are not met. Products that comply with such regulations can be made by removing unreacted diisocyanate monomers until the amount of diisocyanate monomer in (X) of the polyisocyanate composition is 0.1% by mass or less.

[0036] The content of diisocyanate monomers can be measured by gas chromatography using an internal standard, for example, according to ASTM D 3432. Alternatively, it can be measured by liquid chromatography under the following conditions.

[0037] Apparatus: Waters Corporation "ACQUITY UPLC H-Class" Data processing: Waters Corporation "Empower-3" Column: Waters Corporation "ACQUITY UPLC HSS T3" (100 mm × 2.1 mmφ, 1.8 μm) 40℃ Eluent: Ammonium formate aqueous solution / methanol, 0.3 mL / min Detector: PDA Sample preparation: 1. Dissolve 100 mg of appropriately blocked sample in 10 ml of THF (for LC) 2. Stir with a vortex for 30 seconds 3. Dilute appropriately with the eluent (mobile phase) 4. Pass through a 0.2 μm filter to obtain the measurement sample. Calculation of area ratio: Calculated using the maximum absorption wavelength for the target substance.

[0038] The viscosity of the polyisocyanate composition (X) is adjusted to a range suitable for the non-solvent laminating method. For example, the viscosity at 40°C is adjusted to be in the range of 100 to 20,000 mPas, more preferably 500 to 10,000 mPas. The viscosity of the polyisocyanate composition (X) can be adjusted, for example, by the structure of the polyisocyanate compound (A) or by the addition of plasticizers as described later. The viscosity of the polyisocyanate composition (X) is measured, for example, using a rotational viscometer with a cone-plate of 1° × 50 mm in diameter and a shear rate of 100 sec. －１ It can be measured at 40°C ± 1°C.

[0039] (Isocyanate-reactive composition (Y)) The isocyanate-reactive composition (Y) comprises an isocyanate-reactive compound (B), the isocyanate-reactive compound (B) comprising a polyether polyol (B1) with a molecular weight of 700 g / mol or more and 2000 g / mol or less, and an amine compound (B2).

[0040] Examples of polyether polyols (B1) include those obtained by addition polymerization of alkylene oxides such as ethylene oxide, propylene oxide, butylene oxide, styrene oxide, epichlorohydrin, tetrahydrofuran, and cyclohexylene in the presence of a polymerization initiator.

[0041] As polymerization initiators, there are glycols such as ethylene glycol, propylene glycol, 1,3 - propanediol, 1,4 - butanediol, 1,5 - pentanediol, 3 - methyl - 1,5 - pentanediol, 1,6 - hexanediol, neopentyl glycol, methylpentanediol, dimethylbutanediol, butylethylpropanediol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, bishydroxyethoxybenzene, 1,4 - cyclohexanediol, 1,4 - cyclohexanedimethanol, triethylene glycol, etc.;

[0042] trifunctional or tetrafunctional aliphatic alcohols such as glycerin, trimethylolpropane, pentaerythritol, and triol forms of polypropylene glycol;

[0043] amine compounds having active hydrogen groups such as primary or secondary alkylamines such as ethylamine and diethylamine, amine compounds having a plurality of amino groups such as methylenediamine and ethylenediamine, and primary or secondary alkanolamines such as monoethanolamine and diethanolamine.

[0044] The molecular weight of the polyether polyol (B1) is more preferably 700 g / mol or more and more preferably 1500 g / mol or less. The hydroxyl value of the polyether polyol (B1) can be adjusted as appropriate, but as an example, it is preferably 10 mgKOH / g or more and 1200 mgKOH / g or less.

[0045] The content of the polyether polyol (B1) in the isocyanate - reactive compound (B) is preferably 20% by mass or more and 80% by mass or less. It is preferably 25% by mass or more, preferably 30% by mass or more, preferably 75% by mass or less, and preferably 70% by mass or less.

[0046] The amine compound (B2) is a compound having an amino group. In this specification, the amino group refers to NH ２This refers to a group or an NHR group (where R is an alkyl or aryl group which may have a functional group).

[0047] As the amine compound (B2), any known compound can be used without particular limitation, including methylenediamine, ethylenediamine, isophoronediamine, 3,9-dipropanamine-2,4,8,10-tetraoxaspirodoundecane, lysine, 2,2,4-trimethylhexamethylenediamine, hydrazine, piperazine, 2-hydroxyethylethylenediamine, di-2-hydroxyethylethylenediamine, di-2-hydroxyethylpropylenediamine, 2-hydroxypropylethylenediamine, di-2-hydroxypropylethylenediamine, poly(propylene glycol)diamine, poly(propylene glycol)triamine, poly(propylene glycol)tetraamine, 1,2-diaminopropane, 1,3-diaminopropane,

[0048] 1,4-diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane, 1,7-diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane, 1,10-diaminodecane, diethylenetriamine, dipropylenetriamine, triethylenetetramine, tripropylenetetramine, tetraethylenepentamine, tetrapropylenepentamine, pentaethylenehexamine, nonaethylenedecamine, trimethylhexamethylenediamine, tetra(aminomethyl)methane, tetrakis(2-aminoethylaminomethyl)methane, 1,3-bis(2'-aminoethylamino)propane, triethylene-bis(trimethylene)hexamine, bis(3-aminoethyl)amine, bishexamethylenetriamine, 1,4-cyclohexanediamine, 4,4'-methylenebiscyclohexylamine, 4,4'-isopropylidenebiscyclohexylamine, norbornadiamine,

[0049] Amine compounds having multiple amino groups (B2-1), such as bis(aminomethyl)cyclohexane, diaminodicyclohexylmethane, isophoronediamine, mensendiamine, bis(cyanoethyl)diethylenetriamine, 1,4-bis-(8-aminopropyl)-piperazine, piperazine-1,4-diazacycloheptane, 1-(2'-aminoethylpiperazine), 1-[2'-(2''-aminoethylamino)ethyl]piperazine, tricyclodecanediamine, and polyureamines which are reaction products of the above-mentioned polyamines and the above-mentioned isocyanate components.

[0050] Primary or secondary alkanolamines (B2-2) such as monoethanolamine, monoisopropanolamine, monobutanolamine, N-methylethanolamine, N-ethylethanolamine, N-methylpropanolamine, diethanolamine, and diisopropanolamine,

[0051] Primary or secondary amines (B2-3) such as ethylamine, octylamine, laurylamine, myristylamine, stearylamine, oleylamine, diethylamine, dibutylamine, and distearylamine,

[0052] Other examples include polyamino acid esters such as polyaspartate esters, and polymer compounds containing amino groups such as polyamidoamines and polyethyleneimines.

[0053] It is preferable to use an amine compound (B2-1) having multiple amino groups, and more preferable to use a poly(propylene glycol) polyamine such as poly(propylene glycol)diamine, poly(propylene glycol)triamine, or poly(propylene glycol)tetraamine.

[0054] The amount of amine compound (B2) can be adjusted as appropriate depending on the purpose, but as an example, it is preferable that the amine value of the isocyanate reactive composition (Y) be 20 to 100 mg KOH / g, more preferably 25 to 70 mg KOH / g.

[0055] In this specification, the amine value refers to the number of milligrams of KOH equivalent to the amount of HCl required to neutralize 1 g of the sample. There are no particular restrictions, and it can be calculated using known methods. If the chemical structure of the amine compound (B2) and, if necessary, the average molecular weight are known, it can be calculated using the formula: (number of amino groups per molecule / average molecular weight) × 56.1 × 1000. If the chemical structure or average molecular weight of the amine compound is unknown, it can be measured according to known amine value measurement methods, for example, JIS K7237-1995.

[0056] The isocyanate-reactive compound (B) may include compounds having isocyanate-reactive functional groups other than polyether polyols (B1) and amine compounds (B2). Examples of such compounds include polyether polyols other than polyether polyol (B1) (B3), polyester polyols (B4), vegetable oil polyols (B5), polyurethane polyols (B6), sugar alcohols (B7), and other isocyanate-reactive compounds (B8). These can be used individually or in combination of two or more.

[0057] Polyether polyol (B3) is the same as polyether polyol (B1) except for its molecular weight. The molecular weight of polyether polyol (B3) can be adjusted as appropriate, but as an example, it is between 200 g / mol and 4000 g / mol (excluding the range that overlaps with polyether polyol (B1)).

[0058] Furthermore, the amount of polyether polyol (B3-1) with a molecular weight of less than 700 g / mol is 30% by mass or less of the total amount of isocyanate-reactive compound (B). This makes it possible to produce an adhesive with excellent retort resistance. It is more preferable that the content of polyether polyol (B3-1) in the isocyanate-reactive compound (B) is 10% by mass or less. The isocyanate-reactive compound (B) does not have to contain polyether polyol (B3-1).

[0059] Examples of polyester polyols (B4) include polyester polyols obtained as reaction products of polyhydric alcohols and polycarboxylic acids, and lactone-based polyester polyols obtained by polycondensation reactions of aliphatic polyols with various lactones such as ε-caprolactone. It is preferable to use polyester polyols obtained as reaction products of polyhydric alcohols and polycarboxylic acids.

[0060] Examples of polyhydric alcohols include aliphatic diols such as ethylene glycol, diethylene glycol, propylene glycol, 1,3-propanediol, 1,2,2-trimethyl-1,3-propanediol, 2,2-dimethyl-3-isopropyl-1,3-propanediol, 1,4-butanediol, 1,3-butanediol, 3-methyl-1,3-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 1,4-bis(hydroxymethyl)cyclohesane, and 2,2,4-trimethyl-1,3-pentanediol;

[0061] Trimethylolethane, trimethylolpropane, glycerin, hexanetriol, pentaerythritol, and other trifunctional or more aliphatic polyols;

[0062] Bisphenols such as bisphenol A and bisphenol F; alkylene oxide adducts of bisphenols obtained by adding ethylene oxide, propylene oxide, etc. to bisphenols such as bisphenol A and bisphenol F;

[0063] Examples include polyether polyols obtained by ring-opening polymerization of aliphatic diols or polyols with various cyclic ether-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, and these can be used individually or in combination of two or more.

[0064] Examples of polycarboxylic acids include aliphatic dicarboxylic acids such as succinic acid, adipic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, maleic anhydride, fumaric acid, 1,3-cyclopentanedicarboxylic acid, and 1,4-cyclohexanedicarboxylic acid; aromatic dicarboxylic acids such as orthophthalic acid, isophthalic acid, terephthalic acid, 1,4-naphthalenedicarboxylic acid, 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, naphthalic acid, biphenyldicarboxylic acid, and 1,2-bis(phenoxy)ethane-p,p'-dicarboxylic acid; and anhydrides or ester-forming derivatives of these aliphatic or dicarboxylic acids; and polybasic acids such as p-hydroxybenzoic acid, p-(2-hydroxyethoxy)benzoic acid and ester-forming derivatives of these dihydroxycarboxylic acids, and dimer acids, which can be used individually or in combination of two or more.

[0065] The molecular weight of the polyester polyol (B4) can be adjusted as appropriate, but as an example, it is preferably 250 g / mol or more and 20,000 g / mol or less, and more preferably 500 g / mol or more and 20,000 g / mol or less. The hydroxyl value of the polyester polyol (B4) is preferably 5 mg KOH / g or more and 500 mg KOH / g or less.

[0066] The content of polyester polyol (B4) can be adjusted as appropriate, but one example is 10% to 70% by mass of the isocyanate-reactive compound (B).

[0067] Examples of vegetable oil polyols (B5) include castor oil, dehydrated castor oil, hydrogenated castor oil (a hydrogenated product of castor oil), and castor oil alkylene oxide adducts of 5 to 50 moles.

[0068] Polyurethane polyols (B6) are reaction products of low-molecular-weight or high-molecular-weight polyols and polyisocyanate compounds. As low-molecular-weight polyols, those similar to the polyhydric alcohols exemplified as raw materials for polyester polyols (B4) can be used. As high-molecular-weight polyols, those similar to those exemplified as isocyanate-reactive compounds (B) can be used. As polyisocyanate compounds, diisocyanates exemplified as raw materials for polyisocyanate compounds (A2) and polyisocyanate compounds (A3) can be used.

[0069] Examples of sugar alcohols (B7) include pentaerythritol, sucrose, xylitol, sorbitol, isomalt, lactitol, maltitol, and mannitol.

[0070] Other isocyanate-reactive compounds (B8) are compounds having isocyanate-reactive functional groups other than those described above. Their proportion is preferably less than 30% by mass of the isocyanate-reactive compounds, and more preferably less than 15% by mass. In other words, the total amount of (B1) to (B7) in the isocyanate-reactive compounds (B) is preferably 70% by mass or more, and more preferably 85% by mass or more. The isocyanate-reactive compounds (B) do not necessarily contain other isocyanate-reactive compounds (B8).

[0071] The viscosity of the isocyanate-reactive composition (Y) is adjusted to a range suitable for the non-solvent laminating method. For example, the viscosity at 40°C is adjusted to be in the range of 100 to 50,000 mPas, more preferably 100 to 20,000 mPas. The viscosity of the isocyanate-reactive composition (Y) can be adjusted by the skeleton of the isocyanate-reactive compound (B) or by plasticizers, as described later.

[0072] (Other components of the adhesive) The two-component curing adhesive of the present invention may contain components other than those described above. The other components may be included in either or both of the polyisocyanate composition (X) and the isocyanate reactive composition (Y), or they may be prepared separately and mixed with the polyisocyanate composition (X) and the isocyanate reactive composition (Y) immediately before application of the adhesive. The following describes each component.

[0073] Examples of catalysts include metal catalysts, amine catalysts, aliphatic cyclic amide compounds, and quaternary ammonium salts.

[0074] 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.

[0075] Examples of inorganic metal catalysts include those selected from Sn, Fe, Mn, Cu, Zr, Th, Ti, Al, Co, and the like.

[0076] 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.

[0077] 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.

[0078] 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.

[0079] 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.

[0080] Examples of coupling agents include silane coupling agents, titanate-based coupling agents, and aluminum-based coupling agents.

[0081] 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; 3-isocyanatetopropyltrimethoxysilane, 3-isocyanatetopropyltrimethoxysilane. Examples include isocyanate silanes such as natepropyltriethoxysilane; 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.

[0082] 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.

[0083] Examples of aluminum-based coupling agents include acetalkoxyaluminum diisopropylate.

[0084] There are no particular restrictions on the pigments used, and examples include organic 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, pearlescent pigments, and even plastic pigments, as listed in the 1970 edition of the Paint Raw Materials Handbook (compiled by the Japan Paint Manufacturers Association).

[0085] Examples of extender pigments include precipitated barium sulfate, granite powder, precipitated calcium carbonate, calcium bicarbonate, limestone, alumina white, silica, hydrated fine silica (white carbon), ultrafine anhydrous silica (Aerosil), silica sand, talc, precipitated magnesium carbonate, bentonite, clay, kaolin, and yellow ochre.

[0086] Specific examples of organic pigments include various insoluble azo pigments such as Benzidine Yellow, Hansa Yellow, and Laked 4R; soluble azo pigments such as Laked C, Carmine 6B, and Bordeaux 10; various (copper) phthalocyanine pigments such as phthalocyanine blue and phthalocyanine green; various chlorinated dye lakes such as rhodamine lake and methyl violet lake; various mordant dyes such as quinoline lake and fast sky blue; various vat dyes such as anthraquinone pigments, thioindigo pigments, and perinone pigments; various quinacridone pigments such as Syncasia Red B; various dioxazine pigments such as dioxazine violet; various condensed azo pigments such as chromophthal; and aniline black.

[0087] Inorganic pigments include various chromates such as lead yellow, zinc chromate, and molybdate orange; various ferrocyanide compounds such as Prussian blue; various metal oxides such as titanium dioxide, zinc oxide, mapo yellow, iron oxide, red iron oxide, chrome green oxide, 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; these metal flake pigments and mica flake pigments; metallic pigments and pearl pigments such as mica flake pigments coated with metal oxides and mica-like iron oxide pigments; graphite, carbon black, and the like.

[0088] Examples of plastic pigments include "Grandeur PP-1000" and "PP-2000S" manufactured by DIC Corporation.

[0089] The pigments used can be selected appropriately depending on the purpose, but for example, inorganic oxides such as titanium dioxide and zinc oxide are preferred as white pigments because they have excellent durability, weather resistance, and design properties, and carbon black is preferred as a black pigment.

[0090] The amount of pigment added is, for example, 1 to 400 parts by mass per 100 parts by mass of the total non-volatile content of the polyisocyanate composition (X) and the isocyanate reactive composition (Y), and is more preferably 10 to 300 parts by mass to improve adhesion and blocking resistance.

[0091] Examples of acid anhydrides include cyclic aliphatic acid anhydrides, aromatic acid anhydrides, and unsaturated carboxylic acid anhydrides, and one or more can be used in combination. More specifically, examples include 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, and 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.

[0092] 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.

[0093] 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.

[0094] 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, and the like. Phosphoric acid, pyrophosphate, triphosphate, and butyl acid phosphate are preferred.

[0095] Examples of plasticizers 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.

[0096] 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.

[0097] 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.

[0098] 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.

[0099] 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.

[0100] 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, glycerol triacetate, and glycerol tributylate.

[0101] 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.

[0102] Examples of polyester-based plasticizers include adipic acid-based polyesters, sebaciate-based polyesters, and phthalate-based polyesters.

[0103] Examples of carbonate-based plasticizers include propylene carbonate and ethylene carbonate.

[0104] Other 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.

[0105] (Form of the adhesive) The two-component curing adhesive of the present invention is used in a solvent-free form. In this specification, "solvent-free" adhesive refers to an adhesive in which the polyisocyanate composition (X) and isocyanate reactive composition (Y) substantially do not contain 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, and highly soluble organic solvents such as dimethyl sulfoxide and dimethyl sulfamide, particularly ethyl acetate or methyl ethyl ketone, and is used in a method of bonding with another substrate without going through a step of heating in an oven or the like to volatilize the solvent after coating the substrate, so-called non-solvent laminating method. If trace amounts of organic solvent remain in the polyisocyanate composition (X) or isocyanate reactive composition (Y) due to incomplete removal of components or organic solvents used as reaction media during the manufacturing of their raw materials, it is considered that the composition is substantially free of organic solvents. Furthermore, if the isocyanate reactive composition (Y) contains low molecular weight alcohol, the low molecular weight alcohol reacts with the polyisocyanate composition (X) to become part of the coating film, and therefore does not need to be volatilized after coating. Consequently, this form is also treated as a solvent-free adhesive, and the low molecular weight alcohol is not considered an organic solvent.

[0106] 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.

[0107] <Laminate> The laminate of the present invention is obtained by a method having a two-component mixing step, in which an adhesive is prepared by pre-mixing the polyisocyanate composition (X) and the isocyanate reactive composition (Y) of the present invention, applying it to a first substrate, then laminating a second substrate onto the coated surface, and curing the adhesive layer; or by a method having a two-component fractional coating step, in which the polyisocyanate composition (X) and the isocyanate reactive composition (Y) are applied separately to the first substrate and the second substrate, and then the coated surfaces are brought into contact and pressed together to laminate the first substrate and the second substrate, 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.

[0108] The amount of adhesive applied should be adjusted as needed. For example, 1 g / m². ２ 5g / m or more ２ Preferably, 1 g / m ２ 3g / m or more ２ The following applies:

[0109] It is preferable to perform an aging treatment after crimping. The aging temperature is preferably room temperature to 70°C, and the aging time is preferably 6 to 240 hours.

[0110] 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), barrier heat-seal films having an olefin-based heat-sealable resin layer on one or both sides of a barrier resin such as ethylene vinyl alcohol copolymer, polyvinyl alcohol, cyclic polyolefin resin, or cyclic olefin copolymer, polyolefin films such as white polyethylene film, polyvinyl alcohol film, and ethylene-vinyl alcohol copolymer film.

[0111] Furthermore, it is preferable to use a film formed from materials containing biomass-derived components. Biomass films are sold by various companies, and for example, sheets listed in the biomass certified product list provided by the Japan Organic Resources Association can be used.

[0112] A well-known example of a film made from biomass-derived ethylene glycol is derived from ethanol produced from biomass (biomass ethanol). For example, biomass-derived ethylene glycol can be obtained by conventionally known methods, such as a method that produces ethylene glycol via ethylene oxide from biomass ethanol. Alternatively, commercially available biomass ethylene glycol may be used; for example, the biomass ethylene glycol commercially available from India Glycol can be suitably used.

[0113] Alternatively, products using biomass raw materials, distinguished by their biomass plasticity as defined by ISO 16620 or ASTM D6866, are also available. Radioactive carbon-14C exists in the atmosphere at a ratio of 1 in 10¹² atoms, and this ratio does not change even in atmospheric carbon dioxide. Therefore, this ratio does not change in plants that fix carbon dioxide through photosynthesis. For this reason, the carbon in plant-derived resins contains radioactive carbon-14C. In contrast, the carbon in fossil fuel-derived resins contains almost no radioactive carbon-14C. Therefore, by measuring the concentration of radioactive carbon-14C in the resin using an accelerator mass spectrometer, the proportion of plant-derived resin in the resin, i.e., the biomass plasticity, can be determined. Examples of plant-derived low-density polyethylene (PDI) biomass plastics with a biomass plastic content of 80% or more, preferably 90% or more, as defined by ISO 16620 or ASTM D6866, include Braskem's product names "SBC818," "SPB608," "SBF0323HC," "STN7006," "SEB853," and "SPB681," and films made from these materials can be suitably used.

[0114] 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.

[0115] 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.

[0116] 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. This film can be used to create a laminate that provides barrier properties against water vapor, oxygen, alcohol, inert gases, volatile organic compounds (fragrances), etc.

[0117] 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.

[0118] More specific configurations of laminates manufactured using the adhesive of the present invention include, but are not limited to, the following: (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) 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.

[0119] 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 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.

[0120] 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).

[0121] 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. 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 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 the 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).

[0122] 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).

[0123] The base material 1 of configuration (6) 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).

[0124] Examples of the substrate 1 in configuration (7) 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).

[0125] Examples of the base material 1 in configuration (8) 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).

[0126] Examples of base material 1 in configurations (9) and (10) 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).

[0127] Because the adhesive of the present invention has excellent retort resistance, it can be particularly suitable for use in the manufacture of laminates used in the production of packaging materials for such applications. Particularly preferred configurations of the laminate of the present invention include, for example, PET film / adhesive layer / CPP film, PET film / adhesive layer / aluminum foil / adhesive layer / CPP film, PET film / adhesive layer / ny film / adhesive layer / CPP film, PET film / adhesive layer / ny film / adhesive layer / LLDPE film, PET film / adhesive layer / transparent vapor-deposited ny film / adhesive layer / CPP film, PET film / adhesive layer / aluminum foil / adhesive layer / ny film / adhesive layer / CPP film, PET film / adhesive layer / ny film / adhesive layer / aluminum foil / adhesive layer / CPP film, transparent vapor-deposited PET film / adhesive layer / CPP film, transparent vapor-deposited PET film / adhesive layer / ny film / adhesive layer / CPP film, OPP film / adhesive layer / CPP film, OPP film / adhesive layer / transparent vapor-deposited OPP film / adhesive layer / CPP film, Examples include transparent vapor-deposited OPP film / adhesive layer / CPP film, transparent vapor-deposited OPP film / adhesive layer / OPP film / adhesive layer / CPP film, transparent vapor-deposited OPE film / adhesive layer / CPP film, transparent vapor-deposited OPE film / adhesive layer / LLDPE film, Ny film / adhesive layer / CPP film, Ny film / adhesive layer / LLDPE film, transparent vapor-deposited Ny film / adhesive layer / CPP film, gas barrier polyolefin film / adhesive layer / CPP film, etc.

[0128] In these configurations, it is preferable to use heat-resistant grade OPP film, transparent vapor-deposited OPP film, CPP film, and LLDPE film (those that do not shrink easily during boiling or retorting).

[0129] Other preferred configurations of the laminate of the present invention include OPE film / adhesive layer / LLDPE film, MDOPE film / adhesive layer / LLDPE film, HDPE film / adhesive layer / LLDPE film, gas barrier polyolefin film / adhesive layer / LLDPE film, OPP film / adhesive layer / LLDPE film, PET film / adhesive layer / LLDPE film, PET film / adhesive layer / Ny film / adhesive layer / LLDPE film, OPP film / adhesive layer / aluminum-deposited PET film / adhesive layer / LLDPE film, and the like. In the configurations exemplified above, the LLDPE film may be colored white.

[0130] When the laminate has multiple adhesive layers, at least one of the multiple adhesive layers is a cured coating film of the adhesive of the present invention, but the other adhesive layers may or may not be cured coating films of the adhesive of the present invention.

[0131] In addition to the above-described configurations (1) to (10), 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 or may not be the adhesive of the present invention.

[0132] 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.

[0133] 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.

[0134] <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.

[0135] 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 cited. 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.

[0136] 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.

[0137] 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.

[0138] <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.

[0139] 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.

[0140] 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.

[0141] 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.

[0142] 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.

[0143] 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.

[0144] 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.

[0145] 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.

[0146] 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.

[0147] 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.

[0148] 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.

[0149] 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).

[0150] 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.

[0151] 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.

[0152] <Preparation of Polyisocyanate Composition (X)> (Synthesis of Polyurethane Polyisocyanate (A1)) 150 parts by mass of hexamethylene diisocyanate (HDI) was charged into a flask equipped with a stirrer, thermometer, and nitrogen gas inlet tube, stirred under nitrogen gas, and heated to 60°C. 100 parts by mass of polypropylene glycol (hereinafter abbreviated as "PPG") with a number average molecular weight of 400 was added dropwise in several portions, and the mixture was stirred for 5 to 6 hours to complete the urethane formation reaction. Next, using a thin-film distillation apparatus, the HDI in the urethane prepolymer, which is the reaction product of HDI, was purified at a pressure of approximately 0.02 Torr and a temperature of 140°C until the HDI content in the solids was 1% by mass, thereby obtaining polyurethane polyisocyanate (A1). The NCO group content of polyurethane polyisocyanate (A1) was 9%.

[0153] (Synthesis of polyisocyanate compound (A3-2)) In a reaction vessel equipped with a stirrer, thermometer, nitrogen gas inlet tube, rectification tube, moisture separator, etc., 52.9 parts of diethylene glycol, 47.1 parts of adipic acid, and 0.01 parts of titanium tetraisopropoxide were charged under nitrogen gas introduction. 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 460 and a hydroxyl value of 245.1 mg KOH / g.

[0154] In a reaction vessel equipped with a stirrer, thermometer, and nitrogen gas inlet tube, 76.9 parts of a hexamethylene diisocyanate derivative (Takenate D-178NL, manufactured by Mitsui Chemicals, Inc.) were charged and heated to 60°C while stirring under a nitrogen gas stream. 23.1 parts of polyester polyol were added dropwise in several portions, and the mixture was further heated and maintained at an internal temperature of 90°C for 6 hours to carry out the urethane reaction, yielding a polyurethane polyisocyanate with an NCO group content of 10.2% and isocyanate groups at both ends. This was used as the polyisocyanate compound (A3-2).

[0155] (Preparation of Polyisocyanate Composition (X)) Polyisocyanate compositions (X) and (X') were prepared according to the formulations shown in Tables 1 and 2. In the table, polyisocyanate compound (A2) is Duranate D201 (manufactured by Asahi Kasei Corporation, a derivative of hexamethylene diisocyanate, bifunctional), and polyisocyanate compound (A3-1) is Desmodule N-3300 (manufactured by Covestro Inc., a nurate of hexamethylene diisocyanate, 3.5functional).

[0156] <Preparation of Isocyanate Reactive Composition (Y)> (Synthesis of Polyester Polyol (B4)) In a reaction vessel equipped with a stirrer, thermometer, nitrogen gas inlet tube, rectification tube, moisture separator, etc., 54.0 parts of 3-methylpentanediol, 46.0 parts of isophthalic acid, and 0.01 parts of titanium tetraisopropoxide were charged under nitrogen gas introduction. 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 250°C. The esterification reaction was terminated when the acid value became 1 mg KOH / g or less, and polyester polyol (B4) with a number average molecular weight of 500 and a hydroxyl value of 224 was obtained.

[0157] (Preparation of Isocyanate-Reactive Composition (Y)) Polyol compositions (Y) and (Y') were prepared according to the formulations in Table 3. The unit of amine value is mgKOH / g. Details of compounds other than polyester polyol (B4) in the table are as follows.

[0158] Polyether polyol (B1-1): Polypropylene polyol (AGC, exenol 1020 (molecular weight = 1000 g / mol, hydroxyl value = 112 mg KOH / g)) Polyether polyol (B1-2): Polypropylene polyol (AGC, exenol 1030 (molecular weight = 1000 g / mol, hydroxyl value = 163 mg KOH / g)) Polyamine (B2): Polyoxypropylene triamine (Huntsman, Jeffamine T-403, molecular weight = 440, amine value = 355 mg KOH / g) Polyether polyol (B3-1-1): Polypropylene polyol (AGC, exenol 420 (molecular weight = 400 g / mol, hydroxyl value = 280 mg KOH / g)) Polyether polyol (B3-1-2): Polypropylene polyol (AGC Corporation, Exenol 430 (molecular weight = 400 g / mol, hydroxyl value = 400 mg KOH / g))

[0159] <Evaluation> (Adhesion Strength) A polyisocyanate composition (X) was applied to a transparent vapor-deposited polyester film with a thickness of 12 μm (TOPPAN, GL-ARH), and an isocyanate-reactive composition (Y) was applied to a nylon film with a thickness of 15 μm (Unitika, Emblem ONBC RT). The transparent vapor-deposited polyester film and the nylon film were then pressed together using a nip roll (50°C). Next, the same polyisocyanate composition (X) used for bonding the transparent vapor-deposited polyester film and the nylon film was applied to the nylon film surface of the laminate, and the same isocyanate reactive composition (Y) used for bonding the transparent vapor-deposited polyester film and the nylon film was applied to an unstretched polypropylene film for retort processing with a thickness of 70 μm (manufactured by Toray Film Processing Co., Ltd., Trefan NO. ZK207). These were then pressed together with a nip roll (50°C) and aged at 40°C for 48 hours to obtain a laminate of transparent vapor-deposited polyester film / adhesive layer / nylon film / adhesive layer / unstretched polypropylene film. The combinations of polyisocyanate composition (X) and isocyanate reactive composition (Y) of the adhesives in the examples and comparative examples, and their application amounts (g / m²) are shown. ２ The figures are as shown in Tables 4 and 5.

[0160] Test specimens were cut from the aged laminate in 15 mm widths, and the adhesive strength between the transparent vapor-deposited polyester film and nylon film (transparent vapor-deposited PET / Ny) was measured using a tensile testing machine at a peeling speed of 300 mm / min and T-type peeling. The results were evaluated according to the following criteria and summarized in Tables 4 and 5. 5: 4 N / 15 mm or more; 4: 3 N / 15 mm or more, less than 4 N / 15 mm; 3: 2 N / 15 mm or more, less than 3 N / 15 mm; 2: 1 N / 15 mm or more, less than 2 N / 15 mm; 1: less than 1 N / 15 mm

[0161] The adhesive strength (Ny / CPP) between nylon film and unoriented polypropylene film was measured under similar conditions. The results were evaluated according to the following criteria and summarized in Tables 4 and 5. 5: 7N / 15mm or more; 4: 5N / 15mm or more, less than 7N / 15mm; 3: 3N / 15mm or more, less than 5N / 15mm; 2: 2N / 15mm or more, less than 3N / 15mm; 1: less than 2N / 15mm

[0162] (Retort resistance) Test pieces were cut from the laminate after aging was complete, folded so that the unstretched polypropylene film faced inward, and heat-sealed on three sides other than the fold with a width of 10 mm. A 1 / 1 / 1 sauce (meat sauce: vegetable oil: vinegar = 1:1:1) was added as the contents. The filled pouches were retorted in a shower-type retort sterilizer at 121°C for 30 minutes.

[0163] The contents were removed from the retort-treated pouch, and 15 mm wide test pieces were cut from the pouch. The adhesive strength between the transparent vapor-deposited polyester film and nylon film, and between the nylon film and unstretched polypropylene film were measured under the same conditions as for adhesive strength. The results were evaluated using the same criteria as for adhesive strength, and are summarized in Tables 4 and 5.

[0164] (Ink solubility) A urethane-based laminate ink (Finart R794 White G3; manufactured by DIC Corporation) was heated to 15 seconds (25°C) in a Zaan Cup #3 manufactured by Rigosha, and printed onto the transparent vapor-deposited layer of a 12 μm thick transparent vapor-deposited polyester film (manufactured by TOPPAN, GL-ARH) using a gravure printing press equipped with a gravure plate with a plate depth of 43 μm. The printed layer was then dried or cured by passing it through a 70°C oven.

[0165] The prepared polyisocyanate composition (X) and isocyanate-reactive composition (Y) were dropped onto the printed layer, left at 25°C for 20 minutes, and then the dropped areas were rubbed with a cotton swab. The area that remained without peeling of the printed layer was evaluated on the following five-point scale, and the results were summarized as 1 to 3. 5: 75% to 100% 4: 50% to less than 75% 3: 30% to less than 50% 2: 15% to less than 30% 1: 0% to less than 15%

[0166] Furthermore, regarding the ink solubility of the adhesives in the examples and comparative examples, those polyisocyanate compositions (X) and isocyanate reactive compositions (Y) that had a solubility rating of 3 or higher were marked as pass (○), and those that did not were marked as fail (×). The results are summarized in Tables 4 and 5.

[0167]

[0168]

[0169]

[0170]

[0171]

Claims

1. A two-component curable adhesive comprising a polyisocyanate composition (X) containing a polyisocyanate compound (A) and an isocyanate-reactive composition (Y) containing an isocyanate-reactive compound (B), wherein the polyisocyanate compound (A) comprises a polyurethane polyisocyanate (A1), which is a reaction product of a polyether polyol and hexamethylene diisocyanate, and a derivative of a non-aromatic diisocyanate (A2) having an average number of functional groups of 1.8 or more and 2.5 or less, and the isocyanate-reactive compound (B) comprises a polyether polyol (B1) with a molecular weight of 700 g / mol or more and 2000 g / mol or less, and an amine compound (B2), and the content of polyether polyols with a molecular weight of less than 700 g / mol in the isocyanate-reactive compound (B) is 30% by mass or less.

2. The two-component curing adhesive according to claim 1, wherein the proportion of the polyurethane polyisocyanate (A1) to the total amount of the polyurethane polyisocyanate (A1) and the derivative of the non-aromatic diisocyanate (A2) is 10% by mass or more and 90% by mass or less.

3. The two-component curing adhesive according to claim 1, wherein the content of diisocyanate monomer in the polyisocyanate composition (X) is 5% by mass or less.

4. The two-component curing adhesive according to claim 1, wherein the isocyanate-reactive compound (B) further comprises a polyester polyol (B4).

5. The two-component curing adhesive according to claim 1, wherein the amine value of the isocyanate-reactive composition (Y) is 20 to 100 mg KOH / g.

6. The two-component curing adhesive according to claim 1, wherein the ratio [NCO] / [isocyanate-reactive functional groups] of the number of moles [NCO] of isocyanate groups contained in the polyisocyanate composition (X) to the number of moles [isocyanate-reactive functional groups] contained in the isocyanate-reactive composition (Y) is 0.5 to 5.

0.

7. 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 a two-component curing adhesive as described in any one of claims 1 to 6.

8. The laminate according to claim 7, comprising a printed layer disposed between the first substrate and the adhesive layer.

9. A packaging material obtained by forming a bag from the laminate described in claim 7.

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