Adhesive composition, laminate, and packaging material

Abstract

Disclosed are: an adhesive composition which is composed of a fat or oil (A) having an acid anhydride group and a curing agent (H), wherein the curing agent (H) contains an acid-modified polyol (B) and an amine compound (C); a multilayer body which is obtained by sequentially stacking a first base material, an adhesive layer and a second base material in this order, wherein the adhesive layer is formed of the above-described adhesive composition; and a packaging material. It is preferable that: the fat or oil (A) having an acid anhydride group is a maleic acid anhydride-modified vegetable oil (A1); the acid-modified polyol (B) is an acid-modified polyester polyol; and the amine compound (C) contains a tertiary amine-containing polyol.

Description

[Technical field]

[0001] The present invention relates to a two-component curing adhesive composition, and to a laminate and a packaging material obtained by laminating various substrates with the adhesive. [Background technology]

[0002] Laminated films (sometimes referred to as laminate films) used for various packaging materials, labels, etc., are endowed with design, functionality, storage properties, convenience, and transportability by laminating a wide variety of plastic films, metal foils, etc., and in particular, packaging materials obtained by forming such laminated films into bags are used as packaging materials for foods, medicines, detergents, etc. As adhesives used when laminating these films, reactive adhesives (also referred to as two-component adhesives) that combine a polyisocyanate composition and a polyol composition are known.

[0003] Reactive adhesives that combine a polyisocyanate composition and a polyol composition have many advantages, such as not only high adhesive strength but also a moderate curing speed and abundant raw material sources. However, they have problems such as difficulty in handling due to the high reactivity of isocyanates (skin sensitization, inhalation toxicity) and the production of primary aromatic amines, which are carcinogenic substances, during the curing reaction, and there is a demand in the market for safer reactive adhesives.

[0004] Furthermore, in recent years, there is a strong demand for laminated films that are suitable for the collection, separation, and reuse of plastic waste due to the mandatory recycling of plastic containers and packaging. It is generally recognized that reactive adhesives that combine polyisocyanate compositions and polyol compositions are thermosetting resins that are difficult to thermally decompose, and are difficult to recycle. In addition, most of the laminated films in circulation are labeled with product names and decorated with printing inks, etc., and these printing inks cannot be completely separated during the recycling process, so there are also issues such as coloring of recycled products or remaining printed patterns.

[0005] On the other hand, biomass, a biological resource, is attracting attention. In particular, plants grow by absorbing carbon dioxide from the atmosphere through photosynthesis using sunlight as energy, so products made from plant-derived raw materials (biomass plastics, synthetic fibers, etc.) are expected to be developed because the amount of carbon dioxide absorbed by photosynthesis during the plant's growth process is offset by the amount of carbon dioxide emitted by the incineration of the plant, and it is thought that such products will not affect the increase or decrease of carbon dioxide in the atmosphere (carbon neutral). However, the reported biodegradable resins are often highly viscous, and the use of organic solvents is essential for their use, so the impact of the organic solvents discharged after use on the environment cannot be ignored. Thus, it is currently not possible to achieve both biodegradability and adhesiveness that meet the market's requirements. For these reasons, adhesives that combine recyclability and biodegradability are not yet available in the market.

[0006] The present applicants have previously developed an adhesive composition that contains maleic anhydride modified vegetable oil (A1), polyol (B0) and a curing agent (B) containing an amine compound (C) as an adhesive that is highly safe and has adhesive strength comparable to that of conventional reactive adhesives that combine a polyisocyanate composition and a polyol composition (see, for example, Patent Document 1). However, this adhesive was not endowed with functionality in terms of recyclability or biodegradability. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Special Publication No. 2022-518878 Summary of the Invention [Problem to be solved by the invention]

[0008] The problem to be solved by the present invention is to provide a reactive adhesive composition which is highly safe, has an adhesive strength comparable to that of conventional reactive adhesives which combine a polyisocyanate composition and a polyol composition, and provides excellent recyclability and biodegradability of the laminated film. [Means for solving the problem]

[0009] That is, the present invention provides an adhesive composition comprising an oil or fat (A) containing an acid anhydride group and a curing agent (H), the curing agent (H) containing an acid-modified polyol (B) and an amine compound (C).

[0010] The present invention also provides a laminate comprising a first substrate, an adhesive layer and a second substrate laminated in this order, the adhesive layer being made of the adhesive composition.

[0011] The present invention also provides a packaging material obtained by forming the laminate into a bag shape. Effect of the Invention

[0012] The adhesive composition of the present invention is highly safe, has adhesive strength comparable to that of conventional reactive adhesives combining a polyisocyanate composition and a polyol composition, and forms a laminate film that is not only excellent in recyclability but also excellent in biodegradability. Because of its high safety and excellent recyclability and biodegradability, it can be suitably used, particularly as a food packaging bag. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] (Oils and fats containing an acid anhydride group (A)) The fat or oil (A) used in the present invention contains an acid anhydride group. Fats and oils are substances having a structure of esters of fatty acids and glycerin, i.e., triglycerides, and are widely present in the natural biological world. The fats and oils (A) containing an acid anhydride group used in the present invention are preferably fats and oils (A) containing an acid anhydride group, which are fats and oils containing double bonds derived from unsaturated fatty acids in their chemical structure and to which an acid anhydride group has been introduced (added).

[0014] The fats and oils containing double bonds derived from unsaturated fatty acids in their chemical structure are preferably, for example, drying oils (iodine value >130) and / or semi-drying oils (iodine value 100 to 130), and examples of vegetable oils include tung oil, linseed oil, perilla oil, safflower oil, dehydrated castor oil, safflower oil, soybean oil, rapeseed oil, sunflower oil, sesame oil, rice oil, cottonseed oil, corn oil, tall oil, poppy seed oil, walnut oil, pine seed oil, etc. Examples of animal oils include fish oils (sardine oil, saury oil, herring oil, etc.). In addition, in the present invention, regenerated vegetable oils that have been used for edible purposes, such as tempura oil, and then recovered / regenerated can also be used. Among these oils and fats, tung oil, soybean oil, rapeseed oil, and linseed oil are preferably used because of their easy availability.

[0015] In addition, as the acid anhydride group-containing compound used when introducing an acid anhydride group into the oil or fat, a compound having a double bond in the molecule can be used. Examples of such compounds include maleic anhydride, citraconic anhydride, and tetrahydrophthalic anhydride. Among these, maleic anhydride is preferably used because of the ease of introduction and the reactivity of the acid anhydride group.

[0016] An explanation will be given by taking maleic anhydride as an example of an acid anhydride group-containing compound. From the viewpoint of the adhesive strength of the cured adhesive obtained by reacting with the curing agent (H) described below, the amount of maleic anhydride introduced is preferably 19 to 34 g (0.19 to 0.35 mol), more preferably 22 to 29 g (0.22 to 0.30 mol) per 100 g of oil / fat. If the amount of maleic anhydride introduced is too large, the viscosity may increase significantly, making handling difficult.

[0017] A known and commonly used method can be applied as a method for adding maleic anhydride to fats and oils. For example, when a drying oil is used as the fats and oils, a method of Diels-Alder reaction with maleic anhydride at 50 to 150°C, more preferably 60 to 120°C can be applied. When a semi-drying oil is used as the fats and oils, maleic anhydride can be introduced into the fats and oils by a method of Alder-Ene reaction at 150 to 250°C, more preferably 180 to 220°C. A method of reacting maleic anhydride with semi-drying oil until it reaches a certain reaction rate, and then adding drying oil to react with the remaining maleic anhydride can also be used.

[0018] During the reaction, a small amount of organic peroxide or a known polymerization inhibitor may be added. Examples of such polymerization inhibitors include benzoquinone, hydroquinone, hydroquinone monomethyl, tert-butylhydroquinone, dibutylhydroxytoluene, 4-tertiarybutylcatechol, etc. A method of blowing air into the reaction mixture may also be used.

[0019] (Hardening agent (H)) In the present invention, by using the acid-modified polyol (B) as an essential component of the curing agent (H), it is possible to impart alkali solubility while maintaining adhesiveness.

[0020] (Acid-modified polyol (B)) In the present invention, by using the acid-modified polyol (B) as a curing agent, it is possible to impart alkali solubility while maintaining adhesiveness, and also to exhibit excellent biodegradability.

[0021] The acid-modified polyol (B) used in the present invention is a polyol having an acidic group in the polyol molecule. Examples of the acidic group include a carboxyl group and a phosphoric acid group, and among these, a carboxyl group is preferred from the viewpoint of ease of production. The method for producing the acid-modified polyol (B) is not particularly limited, but a method of adding an acid anhydride-containing compound to the hydroxyl group of various polyols to introduce a carboxyl group is preferably used. Examples of the acid anhydride-containing compound to be added to various polyols include trimellitic anhydride, phthalic anhydride, hexahydrophthalic anhydride, succinic anhydride, maleic anhydride, pyromellitic anhydride, etc., and among them, trimellitic anhydride is preferably used. Alternatively, the polyester polyol can be produced by adjusting the composition so that it has both hydroxyl groups and carboxyl groups.

[0022] Examples of the various polyols include polymer polyols selected from polyester polyols, polyether polyols, polyurethane polyols, polyether ester polyols, polyester (polyurethane) polyols, polyether (polyurethane) polyols, acrylic polyols, polycarbonate polyols, polyhydroxyl alkanes, castor oil, and mixtures thereof. Among these, it is preferable to use polyester polyols.

[0023] Examples of polyester polyols include dibasic acids such as terephthalic acid, isophthalic acid, phthalic anhydride, adipic acid, azelaic acid, sebacic acid, and dimer acid (a liquid fatty acid containing monobasic and tribasic acids as well as a C36 dibasic acid produced by dimerization of C18 unsaturated fatty acids derived from vegetable oils and fats as a main component) or their dialkyl esters, or mixtures thereof, and, for example, ethylene glycol, propylene glycol, diethylene glycol, butylene glycol, neopentyl glycol, 2-methyl-1,3-propanediol, 1,6-hexanediol, 3-methyl-1,3-propanediol, 1,6-hexane ... Examples of suitable polyester polyols include polyester polyols obtained by reacting glycols such as di-1,5-pentanediol, 3,3'-dimethylolheptane, polyoxyethylene glycol, polyoxypropylene glycol, and polytetramethylene ether glycol with trihydric or tetrahydric alcohols such as glycerin (glycerol), trimethylolethane, trimethylolpropane, and pentaerythritol, or mixtures thereof, and polyester polyols obtained by ring-opening polymerization of lactones such as polycaprolactone, polyvalerolactone, and poly(β-methyl-γ-valerolactone).

[0024] Also usable are those obtained by adding the above-mentioned acid anhydride group-containing compound to glycols (diols) such as ethylene glycol, propylene glycol, diethylene glycol, 1,4-butanediol, and 1,6-hexanediol, and to trihydric or tetrahydric alcohols such as glycerin, trimethylolethane, trimethylolpropane, and pentaerythritol. Among these, the method of adding an acid anhydride group-containing compound to a polyester polyol is preferred because it can impart excellent delamination properties and biodegradability.

[0025] The acid value of the acid-modified polyol (B) is preferably in the range of 5 to 40 mgKOH / g, more preferably in the range of 10 to 30 mgKOH / g, where the acid value is a value measured according to JIS K0070.

[0026] The hydroxyl value of the acid-modified polyol (B) is preferably 50 to 330 (mg-KOH / g), and more preferably in the range of 100 to 250. If the hydroxyl value is less than 50 (mg-KOH / g), the viscosity of the acid-modified polyol (B) may increase, making it difficult to handle, whereas if the hydroxyl value is more than 330 (mg-KOH / g), sufficient adhesive strength may not be obtained. The hydroxyl value is a value measured according to JIS K0070.

[0027] The molecular weight of the acid-modified polyol (B) is, in terms of weight average molecular weight, in the range of 1500 to 8000, and more preferably in the range of 2500 to 5000. The molecular weight is a value measured by gel permeation chromatography (GPC) under the following conditions.

[0028] Measurement equipment: High-speed GPC equipment (Tosoh Corporation "HLC-8220GPC") Column: The following columns manufactured by Tosoh Corporation were used in series connection. "TSKgelG5000" (7.8mmI.D. x 30cm) x 1 "TSKgelG4000" (7.8mmI.D. x 30cm) x 1 "TSKgelG3000" (7.8mmI.D. x 30cm) x 1 "TSKgelG2000" (7.8mmI.D. x 30cm) x 1 Detector: RI (differential refractometer) Column temperature: 40℃ Eluent: tetrahydrofuran (THF) Flow rate: 1.0mL / min Injection volume: 100 μL (sample concentration 0.4% by mass in tetrahydrofuran solution) Standard sample: Prepare a calibration curve using the following standard polystyrene.

[0029] [Standard polystyrene] "TSKgel Standard Polystyrene A-500" manufactured by Tosoh Corporation "TSKgel Standard Polystyrene A-1000" manufactured by Tosoh Corporation "TSKgel Standard Polystyrene A-2500" manufactured by Tosoh Corporation "TSKgel Standard Polystyrene A-5000" manufactured by Tosoh Corporation "TSKgel Standard Polystyrene F-1" manufactured by Tosoh Corporation "TSKgel Standard Polystyrene F-2" manufactured by Tosoh Corporation "TSKgel Standard Polystyrene F-4" manufactured by Tosoh Corporation "TSKgel Standard Polystyrene F-10" manufactured by Tosoh Corporation "TSKgel Standard Polystyrene F-20" manufactured by Tosoh Corporation "TSKgel Standard Polystyrene F-40" manufactured by Tosoh Corporation "TSKgel Standard Polystyrene F-80" manufactured by Tosoh Corporation "TSKgel Standard Polystyrene F-128" manufactured by Tosoh Corporation "TSKgel Standard Polystyrene F-288" manufactured by Tosoh Corporation "TSKgel Standard Polystyrene F-550" manufactured by Tosoh Corporation

[0030] (Amine Compound (C)) In the present invention, the curing agent preferably contains at least one amine compound (C) in addition to the acid-modified polyol (B). The amine compound (C) not only contributes to the formation of a cured adhesive as a curing agent, but also improves the curing speed by allowing the nitrogen contained in the structure to act as a catalyst to promote the reaction between an acid anhydride group and a hydroxyl group. As the amine compound (C), one type of amine compound may be used, or multiple types of amine compounds may be used in combination. The amine compound (C) is preferably a compound containing two or more primary and / or secondary amino groups in one molecule, or a compound containing one or more tertiary amino groups in one molecule, and examples thereof include tertiary amine-containing polyol (B2) having multiple hydroxyl groups, amide polyol, polyamine, etc. In particular, tertiary amine-containing polyol (B2) is preferably used because it is easy to adjust the balance between the reactivity with the oil (A) containing an acid anhydride group and the physical properties of the film formed. In addition, amino alcohols having both a primary or secondary amino group and a hydroxyl group in one molecule can also be used. Examples of such amino alcohols include monomethanolamine, N-methylmethanolamine, N-ethylmethanolamine, dimethanolamine, monoethanolamine, N-methylethanolamine, N-ethylethanolamine, diethanolamine, etc.

[0031] The tertiary amine-containing polyol (B2) is preferably a tertiary amine compound having a plurality of hydroxyl groups, particularly preferably having 2 to 6 hydroxyl groups. The tertiary amine-containing polyol may have one or more tertiary amino groups, but preferably has 1 to 2 tertiary amino groups. Specific examples include polypropylene glycol ethylene diamine ether, tri(1,2-polypropylene glycol)amine, N-ethyldiethanolamine, N-methyl-N-hydroxyethyl-N-hydroxyethoxyethylamine, pentakishydroxypropyldiethylenetriamine, and tetrakishydroxypropylethylenediamine.

[0032] The tertiary amine-containing polyol (B2) may be a commercially available product, such as TE-360 (a tertiary amine-containing trifunctional polyol manufactured by Guodu Chemical Co., Ltd. (China)), TD-401 (a tertiary amine-containing tetrafunctional polyol manufactured by Guodu Chemical Co., Ltd. (China)), EDP-300, EDP-450 (all of which are tertiary amine-containing tetrafunctional polyols manufactured by Adeka Corporation), and the like.

[0033] Examples of the amide polyol include polyesteramide polyols, and examples of the polyesteramide polyols include polyesteramide polyols obtained by using, in addition to aliphatic diamines having amino groups, such as ethylenediamine, propylenediamine, and hexamethylenediamine, as raw materials in the esterification reaction of the polyester polyols.

[0034] The polyamine is not particularly limited, and any known polyamine having a primary and / or secondary amino group can be used. The polyamine may also contain a tertiary amine.

[0035] For example, aliphatic diamines (having 2 to 18 carbon atoms) include alkylene (having 2 to 6 carbon atoms) diamines such as ethylenediamine, propylenediamine, trimethylenediamine, tetramethylenediamine, and hexamethylenediamine, and polyalkylene (having 2 to 6 carbon atoms) diamines such as diethylenetriamine, iminobispropylamine, bis(hexamethylene)triamine, triethylenetetramine, tetraethylenepentamine, and pentaethylenehexamine, and

[0036] Aliphatic diamines with alkyl (1 to 4 carbon atoms) or hydroxyalkyl (2 to 4 carbon atoms) substitutions, such as dialkyl (1 to 3 carbon atoms) aminopropylamine, trimethylhexamethylenediamine, aminoethylethanolamine, 2,5-dimethyl-2,5-hexamethylenediamine, and methyliminobispropylamine,

[0037] Alicyclic or heterocyclic aliphatic diamines include alicyclic diamines (having 4 to 15 carbon atoms) such as 1,3-diaminocyclohexane, isophoronediamine, menthenediamine, and 4,4'-methylenedicyclohexanediamine (hydrogenated methylenedianiline), and heterocyclic diamines (having 4 to 15 carbon atoms) such as piperazine, N-aminoethylpiperazine, 1,4-diaminoethylpiperazine, and 3,9-bis(3-aminopropyl)-2,4,8,10-tetraoxaspiro[5,5]undecane, and the like.

[0038] Examples of the aromatic ring-containing aliphatic amines (having 8 to 15 carbon atoms) include xylylenediamine and tetrachloro-p-xylylenediamine.

[0039] Examples of aromatic diamines (having 6 to 20 carbon atoms) include unsubstituted aromatic diamines such as 1,2-, 1,3-, or 1,4-phenylenediamine, 2,4'- and 4,4'-diphenylmethanediamine, crude diphenylmethanediamine (polyphenylpolymethylenepolyamine), diaminodiphenylsulfone, benzidine, thiodianiline, 2,6-diaminopyridine, m-aminobenzylamine, triphenylmethane-4,4',4"-triamine, and naphthylenediamine;

[0040] Aromatic diamines having a nucleus-substituted alkyl group (an alkyl group having 1 to 4 carbon atoms, such as a methyl group, an ethyl group, a propyl group, and a butyl group), such as 2,4- or 2,6-tolylenediamine, crude tolylenediamine, diethyltolylenediamine, 4,4'-diamino-3,3'-dimethyldiphenylmethane, 4,4'-bis(o-toluidine), dianisidine, diaminoditolylsulfone, 1,3-dimethyl-2,4-diaminobenzene, 2,3-dimethyl-1,4-diaminonaphthalene, and 4,4'-diamino-3,3'-dimethyldiphenylmethane, and mixtures of these isomers in various ratios,

[0041] Aromatic diamines having nuclear-substituted electron-withdrawing groups (halogen atoms such as fluorine, chlorine, bromine, and iodine; alkoxy groups such as methoxy and ethoxy; nitro groups, etc.), such as methylenebis-o-chloroaniline, 4-chloro-o-phenylenediamine, 2-chloro-1,4-phenylenediamine, 3-amino-4-chloroaniline, 4-bromo-1,3-phenylenediamine, 2,5-dichloro-1,4-phenylenediamine, 5-nitro-1,3-phenylenediamine, and 3-dimethoxy-4-aminoaniline,

[0042] Aromatic diamines having a secondary amino group (aromatic diamines in which part or all of -NH2 is substituted with -NH-R' (R' is an alkyl group; for example, a lower alkyl group such as a methyl group or an ethyl group)) such as 4,4'-di(methylamino)diphenylmethane and 1-methyl-2-methylamino-4-aminobenzene,

[0043] Polyamide polyamines (low molecular weight polyamide polyamines obtained by condensation of dicarboxylic acids (dimer acids, etc.) with excess (2 moles or more per mole of acid) polyamines (the above alkylenediamines and polyalkylene polyamines, etc.), etc.

[0044] Examples of the polyether polyamine include hydrogenated cyanoethylated polyether polyols (such as polyalkylene glycols).

[0045] Among the above polyamines, polyamidoamines and polyether polyamines are preferably used because they are capable of forming a coating film having excellent strength.

[0046] Commercially available polyamines may also be used, such as Jeffamine T-403, Jeffamine D-230, and Jeffamine D-400 (all of which are polyether polyamines manufactured by Huntsman Chemical Co., USA).

[0047] In the case of polyether polyamines, those which are preferably bifunctional or trifunctional and have a molecular weight of 200 to 5,000, more preferably 200 to 1,500, are preferably used.

[0048] (Non-acid-modified polyol (B3)) In the present invention, it is also preferable to use a non-acid-modified polyol (B3) in combination as a curing agent.

[0049] As the non-acid-modified polyol (B3), for example, a compound having two or more hydroxyl groups on average in the molecule can be suitably used, and examples thereof include polymer polyols selected from polyester polyols, polyether polyols, polyurethane polyols, polyether ester polyols, polyester (polyurethane) polyols, polyether (polyurethane) polyols, acrylic polyols, polycarbonate polyols, polyhydroxyl alkanes, castor oil, and mixtures thereof. Among these, it is preferable to use polyester polyols.

[0050] Examples of polyester polyols include dibasic acids such as terephthalic acid, isophthalic acid, phthalic anhydride, adipic acid, azelaic acid, sebacic acid, and dimer acid (a liquid fatty acid containing monobasic and tribasic acids as well as a C36 dibasic acid produced by dimerization of C18 unsaturated fatty acids derived from vegetable oils and fats as a main component) or their dialkyl esters, or mixtures thereof, and, for example, ethylene glycol, propylene glycol, diethylene glycol, butylene glycol, neopentyl glycol, 2-methyl-1,3-propanediol, 1,6-hexanediol, 3-methyl-1,3-propanediol, 1,6-hexane ... Examples of the polyester polyols include polyester polyols obtained by reacting glycols such as di-1,5-pentanediol, 3,3'-dimethylolheptane, polyoxyethylene glycol, polyoxypropylene glycol, and polytetramethylene ether glycol, trihydric or tetrahydric alcohols such as glycerin (glycerol), trimethylolethane, trimethylolpropane, and pentaerythritol, or mixtures thereof, with the polyester polyols, and polyester polyols obtained by ring-opening polymerization of lactones such as polycaprolactone, polyvalerolactone, and poly(β-methyl-γ-valerolactone).

[0051] Examples of polyether polyols include polyether polyols obtained by polymerizing oxirane compounds such as ethylene oxide, propylene oxide, butylene oxide, and tetrahydrofuran using low molecular weight polyols such as water, ethylene glycol, propylene glycol, trimethylolpropane, and glycerin as an initiator. Examples of polyether ester polyols include polyether ester polyols obtained by reacting the above polyether polyols with dibasic acids such as terephthalic acid, isophthalic acid, phthalic anhydride, adipic acid, azelaic acid, sebacic acid, and dimer acid, or dialkyl esters thereof, or mixtures thereof.

[0052] The polyurethane polyol is a polyol having a urethane bond in one molecule, and is, for example, a reaction product of a polyether polyol having a number average molecular weight of 200 to 20,000 and an organic polyisocyanate, preferably having an NCO / OH ratio of less than 1, more preferably 0.9 or less. As the organic polyisocyanate, a polyisocyanate compound, particularly a diisocyanate compound, described below, can be used.

[0053] Polyether (polyurethane) polyols and polyester (polyurethane) polyols are reaction products of polyester polyols, polyether ester polyols, or the like with organic polyisocyanates, and preferably have an NCO / OH ratio of less than 1, more preferably 0.9 or less.

[0054] Examples of polycarbonate polyols include those obtained by reacting one or more glycols selected from ethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,9-nonanediol, 1,8-nonanediol, neopentyl glycol, diethylene glycol, dipropylene glycol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, bisphenol A, and hydrogenated bisphenol A with dimethyl carbonate, diphenyl carbonate, ethylene carbonate, phosgene, or the like.

[0055] Examples of acrylic polyols include hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxybutyl acrylate, etc., which contain one or more hydroxyl groups in one molecule, or corresponding methacrylic acid derivatives thereof, which are obtained by copolymerizing with, for example, acrylic acid, methacrylic acid, or an ester thereof. The polyhydroxyalkane may be a liquid rubber obtained by copolymerizing butadiene or butadiene with acrylamide or the like.

[0056] In the case of polyester polyol, those having a number average molecular weight of 400 to 2000 and a hydroxyl value of 60 to 300 can be preferably used.

[0057] Furthermore, glycols (diols) such as ethylene glycol, propylene glycol, diethylene glycol, 1,4-butanediol, and 1,6-hexanediol, and trihydric or tetrahydric alcohols such as glycerin, trimethylolpropane, and pentaerythritol can also be used as they are as part of the hardener (H).

[0058] The above non-acid-modified polyols (B3) may be used alone or in combination.

[0059] (Acid value of hardener (H)) The acid value of the curing agent (H) as a whole of the curing agent (H) containing the acid-modified polyol (B), the amine compound (C), and other compounds as necessary, is preferably in the range of 5 to 30 mgKOH / g, and more preferably in the range of 10 to 20 mgKOH / g. As long as the acid value of the curing agent (H) is within the above range, the acid-modified polyol (B) and the non-acid-modified polyol (B3) may be mixed and used.

[0060] The compounding ratio of the fats and oils (A) containing an acid anhydride group to the curing agent (H) is preferably in the range of 0.5 to 1.5, more preferably 0.8 to 1.25, in terms of the molar ratio of the fats and oils (A) containing an acid anhydride group to the functional group reactive with the fats and oils (H) containing an acid anhydride group (acid anhydride group / functional group reactive with the acid anhydride group). If the compounding ratio of the fats and oils (A) containing an acid anhydride group to the curing agent (H) is in the above range, a coating having excellent adhesive strength can be obtained.

[0061] When the curing agent (H) contains an amine compound (C), the amount of the amine compound (C) used is preferably in the range of 0.05 to 0.7, more preferably 0.1 to 0.5, in terms of the molar ratio (nitrogen / acid anhydride group) of the nitrogen of the amine compound (C) to the acid anhydride group of the oil or fat (A) containing the acid anhydride group. If the amount of the amine compound (C) used is within the above range, an adhesive cured product having excellent adhesive strength can be obtained while ensuring an appropriate pot life.

[0062] Specific preferred combinations of the oil (A) containing an acid anhydride group and the hardener (H) include, for example, 1) A combination of maleic anhydride-modified tung oil as the oil (A) and an acid-modified polyester polyol (B) and a tertiary amine-containing polyol (B2) as the hardener (H), 2) A combination of maleic anhydride modified soybean oil as the fat (A), an acid modified polyester polyol (B) as the hardener (H), a non-acid modified polyol (B3) and a tertiary amine-containing polyol (B2), 3) In 1) to 2), the vegetable oil of the fat (A) may be a combination of a plurality of vegetable oils, such as soybean oil and tung oil.

[0063] (catalyst) A catalyst may be added to the adhesive composition of the present invention. Examples of such a catalyst include tertiary amine compounds, aliphatic cyclic amide compounds, and organometallic catalysts. Examples of the tertiary amine compound include diazabicycloundecene, diazabicyclononene, triethylenediamine, 2-methyltriethylenediamine, quinuclidine, and 2-methylquinuclidine.

[0064] Examples of the aliphatic cyclic amide compounds include δ-valerolactam, ε-caprolactam, ω-enantholactam, η-capryllactam, and β-propiolactam.

[0065] Examples of the organometallic catalyst include dibutyltin oxide, dibutyltin diacetate, dibutyltin dilaurate, dioctyltin dilaurate, bismuth octoate, bismuth neodecanoate, zirconium octoate, and zirconium neodecanoate.

[0066] Among these, tertiary amine compounds are preferably used because of their excellent catalytic activity.

[0067] (solvent) The adhesive composition of the present invention can be used as a solvent-based or solventless adhesive. The "solvent" of the solventless adhesive in the present invention refers to a highly soluble organic solvent capable of dissolving the polyisocyanate compound and polyol compound used in the present invention, and "solventless" refers to the absence of these highly soluble organic solvents. Specific examples of highly soluble organic solvents include toluene, xylene, methylene chloride, tetrahydrofuran, methanol, ethanol, isopropyl alcohol, methyl acetate, ethyl acetate, n-butyl acetate, acetone, methyl ethyl ketone (MEK), cyclohexanone, toluene, xylol, n-hexane, and cyclohexane. Among these, toluene, xylene, methylene chloride, tetrahydrofuran, methyl acetate, and ethyl acetate are known as organic solvents with particularly high solubility.

[0068] On the other hand, when a low viscosity is required, the adhesive of the present invention may be diluted with the organic solvent having high solubility according to the desired viscosity. In that case, either one of the oil having an acid anhydride group (A) or the curing agent (H) may be diluted, or both may be diluted. Examples of organic solvents used in such cases include methanol, ethanol, isopropyl alcohol, methyl acetate, ethyl acetate, n-butyl acetate, acetone, methyl ethyl ketone (MEK), cyclohexanone, toluene, xylol, n-hexane, and cyclohexane. Among these, ethyl acetate and methyl ethyl ketone (MEK) are preferred from the viewpoint of solubility, and ethyl acetate is particularly preferred. The amount of organic solvent used depends on the required viscosity, but is often used in the range of about 20 to 50% by mass.

[0069] (Other optional ingredients) The adhesive composition of the present invention may be used in combination with a pigment, if necessary. In this case, the pigment that can be used is not particularly limited, and examples thereof include organic pigments and inorganic pigments such as extender pigments, white pigments, black pigments, gray pigments, red pigments, brown pigments, green pigments, blue pigments, metal powder pigments, luminescent pigments, and pearlescent pigments, as well as plastic pigments, which are listed in the Paint Raw Materials Handbook 1970 Edition (edited by the Japan Paint Manufacturers Association). Specific examples of these colorants include various types, and examples of organic pigments include various insoluble azo pigments such as Benzidine Yellow, Hansa Yellow, Lake 4R, etc.; soluble azo pigments such as Lake C, Carmine 6B, Bordeaux 10, etc.; various (copper) phthalocyanine pigments such as Phthalocyanine Blue and Phthalocyanine Green, etc.; various chlorine dyeing lakes such as Rhodamine Lake and Methyl Violet Lake, etc.; various mordant dye pigments such as Quinoline Lake and Fast Sky Blue, etc.; various vat dye pigments such as Anthraquinone pigments, Thioindigo pigments, Perinone pigments, etc.; various quinacridone pigments such as Synchasia Red B, etc.; various dioxazine pigments such as Dioxazine Violet, etc.; various condensed azo pigments such as Chromophtal, etc.; aniline black, etc.

[0070] Examples of inorganic pigments include various chromates such as yellow lead, zinc chromate, and molybdate orange; various ferrocyanide compounds such as Prussian blue; various metal oxides such as titanium oxide, zinc oxide, mapico yellow, iron oxide, red iron oxide, chrome oxide green, and zirconium oxide; various sulfides or selenides such as cadmium yellow, cadmium red, and mercury sulfide; various sulfates such as barium sulfate and lead sulfate; various silicates such as calcium silicate and ultramarine blue; various carbonates such as calcium carbonate and magnesium carbonate; various phosphates such as cobalt violet and manganese purple; various metal powder pigments such as aluminum powder, gold powder, silver powder, copper powder, bronze powder, and brass powder; flake pigments of these metals, mica flake pigments; metallic pigments and pearl pigments such as mica flake pigments coated with metal oxides and micaceous iron oxide pigments; graphite, carbon black, and the like.

[0071] Examples of extender pigments include precipitated barium sulfate, powdered gourd, precipitated calcium carbonate, calcium bicarbonate, kansui stone, alumina white, silica, hydrous fine silica (white carbon), ultrafine anhydrous silica (aerosil), silica sand, talc, precipitated magnesium carbonate, bentonite, clay, kaolin, and yellow earth.

[0072] Furthermore, examples of plastic pigments include "Grandol PP-1000" and "PP-2000S" manufactured by DIC Corporation.

[0073] As the pigments used in the present invention, inorganic oxides such as titanium oxide and zinc oxide as white pigments, and carbon black as black pigments are more preferred because they are excellent in durability, weather resistance and design properties.

[0074] The mass proportion of the pigment used in the present invention is 1 to 400 parts by mass, and more preferably 10 to 300 parts by mass, relative to 100 parts by mass of the solid content of the adhesive composition of the present invention, as this provides excellent adhesion, blocking resistance, etc.

[0075] (Adhesion promoter) The adhesive composition used in the present invention may also contain an adhesion promoter, such as a silane coupling agent, a titanate coupling agent, an aluminum coupling agent, or an epoxy resin.

[0076] Examples of silane coupling agents include aminosilanes such as γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, N-β(aminoethyl)-γ-aminopropyltrimethoxysilane, N-β(aminoethyl)-γ-aminopropyltrimethyldimethoxysilane, and N-phenyl-γ-aminopropyltrimethoxysilane; epoxysilanes such as β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, and γ-glycidoxypropyltriethoxysilane; vinylsilanes such as vinyltris(β-methoxyethoxy)silane, vinyltriethoxysilane, vinyltrimethoxysilane, and γ-methacryloxypropyltrimethoxysilane; hexamethyldisilazane, γ-mercaptopropyltrimethoxysilane, and the like.

[0077] Examples of titanate coupling agents include tetraisopropoxytitanium, tetra-n-butoxytitanium, butyl titanate dimer, tetrastearyl titanate, titanium acetylacetonate, titanium lactate, tetraoctylene glycol titanate, titanium lactate, and tetrastearoxytitanium.

[0078] Examples of aluminum-based coupling agents include acetoalkoxyaluminum diisopropylate.

[0079] Examples of epoxy resins include epoxydized oils and fats, such as epoxidized soybean oil, which is generally available on the market; various epoxy resins such as epibis type, novolac type, β-methyl epichlorohydrin type, cyclic oxirane type, glycidyl ether type, glycidyl ester type, polyglycol ether type, glycol ether type, epoxidized fatty acid ester type, polyvalent carboxylic acid ester type, aminoglycidyl type, and resorcin type; and compounds such as triglycidyl tris(2-hydroxyethyl)isocyanurate, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, acrylic glycidyl ether, 2-ethylhexyl glycidyl ether, phenyl glycidyl ether, phenol glycidyl ether, pt-butylphenyl glycidyl ether, adipic acid diglycidyl ester, o-phthalic acid diglycidyl ester, glycidyl methacrylate, and butyl glycidyl ether. However, it is preferable to keep the amount to a minimum.

[0080] Examples of additives that can be used other than those mentioned above include leveling agents, inorganic fine particles such as colloidal silica and alumina sol, polymethyl methacrylate-based organic fine particles, defoamers, anti-sagging agents, wetting and dispersing agents, viscosity adjusters, UV absorbers, metal deactivators, peroxide decomposers, flame retardants, reinforcing agents, plasticizers, lubricants, rust inhibitors, fluorescent brighteners, inorganic heat ray absorbers, flame retardants, antistatic agents, dehydrating agents, known and commonly used thermoplastic elastomers, tackifiers, phosphoric acid compounds, melamine resins, and reactive elastomers. The content of these additives can be appropriately adjusted within a range that does not impair the function of the adhesive composition used in the present invention.

[0081] These additives can be used by mixing with either the oil or fat (A) containing an acid anhydride group or the hardener (H), or by blending as a third component at the time of application.

[0082] (Laminate) The laminate of the present invention is a laminate obtained by laminating a first substrate, an adhesive layer, and a second substrate in this order. Specifically, the laminate is obtained by bonding the first substrate, which is a film, paper, or the like, and the second substrate using the adhesive of the present invention by a dry lamination method or a non-solvent lamination method.

[0083] (First substrate, second substrate) The first substrate and the second substrate can be appropriately selected according to the desired application without any particular limitation, but the adhesive of the present invention can maximize its effect when it is a plastic film. For example, plastic films are mainly used as substrates for packaging materials for food, medicine, detergent, etc., which are the main applications of the present invention. In addition, these plastic films may be appropriately provided with layers according to the desired application, such as a vapor deposition layer of metal such as aluminum or metal oxide such as silica or alumina, a functional coating layer, a printed layer, or a primer layer for facilitating the provision of a printed layer or a vapor deposition layer. On the other hand, a laminate using a reactive adhesive other than the adhesive of the present invention may be used, but there is a possibility that the recyclability may be poor.

[0084] (film) There is no particular limitation on the film, and a film can be appropriately selected according to the application. For example, for food packaging, polyolefin films such as polyethylene terephthalate (PET) film, polystyrene film, polyamide film, polyacrylonitrile film, polyethylene film (LLDPE: low density polyethylene film, HDPE: high density polyethylene film) and polypropylene film (CPP: non-oriented polypropylene film, OPP: biaxially oriented polypropylene film), polyvinyl alcohol film, ethylene-vinyl alcohol copolymer film, etc. can be mentioned.

[0085] The film may be one that has been subjected to a stretching treatment. As a stretching method, a typical method is to melt-extrude a resin into a sheet shape by an extrusion film forming method or the like, and then perform simultaneous biaxial stretching or sequential biaxial stretching. In the case of sequential biaxial stretching, it is common to first perform longitudinal stretching and then transverse stretching. Specifically, a method is often used in which longitudinal stretching utilizing the speed difference between rolls and transverse stretching using a tenter are combined.

[0086] As described above, a film laminated with a vapor-deposited layer of a metal such as aluminum, or a metal oxide such as silica or alumina, or a barrier film containing a gas barrier layer of polyvinyl alcohol, ethylene-vinyl alcohol copolymer, vinylidene chloride, etc. may be used in combination. By using such a film, a laminate having a barrier property against water vapor, oxygen, alcohol, inert gas, volatile organic compounds (fragrances), etc. can be obtained.

[0087] The film surface may be subjected to various surface treatments such as flame treatment and corona discharge treatment as necessary so that an adhesive layer free from defects such as film breakage and repellency is formed.

[0088] Alternatively, the laminate of the present invention can be obtained by applying the adhesive of the present invention as an adhesive auxiliary (anchor coating agent) to a film using a laminator, carrying out a curing reaction, and then laminating a polymer material melted by an extruder (extrusion lamination method). As the film, the same films as those used in the above-mentioned dry lamination method and non-solvent lamination method can be used. As the polymer material to be melted, polyolefin resins such as low-density polyethylene resin, linear low-density polyethylene resin, and ethylene-vinyl acetate copolymer resin are preferred.

[0089] More specifically, the laminate has the following structure: (1) Base film 1 / adhesive layer 1 / sealant film (2) Base film 1 / adhesive layer 1 / metal-deposited unstretched film (3) Base film 1 / adhesive layer 1 / metal-deposited stretched film (4) Transparent vapor-deposited stretched film / adhesive layer 1 / sealant film (5) Base film 1 / adhesive layer 1 / base film 2 / adhesive layer 2 / sealant film (6) Base film 1 / adhesive layer 1 / metal-deposited stretched film / adhesive layer 2 / sealant film (7) Base film 1 / adhesive layer 1 / transparent vapor-deposited stretched film / adhesive layer 2 / sealant film (8) Base film 1 / adhesive layer 1 / metal layer / adhesive layer 2 / sealant film (9) Base film 1 / adhesive layer 1 / base film 2 / adhesive layer 2 / metal layer / adhesive layer 3 / sealant film (10) Base film 1 / adhesive layer 1 / metal layer / adhesive layer 2 / base film 2 / adhesive layer 3 / sealant film These include, but are not limited to, the following:

[0090] Examples of the base film 1 used in the configuration (1) include OPP film, PET film, nylon film, etc. In addition, the base film 1 may be coated with a coating for the purpose of improving the gas barrier property and the ink receptivity when a printing layer is provided, which will be described later. Examples of commercially available base films 1 with coatings include K-OPP film and K-PET film. The adhesive layer 1 is a cured coating film of the adhesive of the present invention. Examples of sealant films include CPP film and LLDPE film. A printing layer, which will be described later, may be provided on the surface of the base film 1 on the adhesive layer 1 side (when a coating is used as the base film 1, the surface of the coating layer on the adhesive layer 1 side). The printing layer is formed by a general printing method that has been used for printing on polymer films using various printing inks such as gravure ink, flexo ink, offset ink, stencil ink, and inkjet ink.

[0091] Examples of the base film 1 used in structures (2) and (3) include an OPP film and a PET film. The adhesive layer 1 is a cured coating of the adhesive of the present invention. As the metal-vapor-deposited unstretched film, a VM-CPP film obtained by depositing a metal such as aluminum on a CPP film can be used, and as the metal-vapor-deposited stretched film, a VM-OPP film obtained by depositing a metal such as aluminum on an OPP film can be used. As in structure (1), a printed layer, which will be described later, may be provided on the surface of the base film 1 on the adhesive layer 1 side.

[0092] Examples of the transparent vapor-deposited stretched film used in the structure (4) include films obtained by vapor-depositing silica or alumina on OPP film, PET film, nylon film, etc. For the purpose of protecting the inorganic vapor-deposited layer of silica or alumina, a film with a coating on the vapor-deposited layer may be used. The adhesive layer 1 is a cured coating of the adhesive of the present invention. Examples of the sealant film include the same as those in the structure (1). A printed layer, which will be described later, may be provided on the surface of the transparent vapor-deposited stretched film on the adhesive layer 1 side (when a film with a coating on the inorganic vapor-deposited layer is used, the surface of the coating layer on the adhesive layer 1 side). The method of forming the printed layer is the same as in the structure (1).

[0093] The base film 1 used in the structure (5) may be a PET film or the like. The base film 2 may be a nylon film or the like. At least one of the adhesive layer 1 and the adhesive layer 2 is a cured coating film of the adhesive of the present invention. The sealant film may be the same as that in the structure (1). As in the structure (1), a printing layer described later may be provided on the surface of the base film 1 on the adhesive layer 1 side.

[0094] Examples of the base film 1 in the structure (6) include those similar to those in the structures (2) and (3). Examples of the metal-vapor-deposited stretched film include a VM-OPP film or a VM-PET film in which a metal such as aluminum is vapor-deposited on an OPP film or a PET film. At least one of the adhesive layer 1 and the adhesive layer 2 is a cured coating film of the adhesive of the present invention. Examples of the sealant film include those similar to those in the structure (1). As in the structure (1), a printed layer, which will be described later, may be provided on the surface of the base film 1 on the adhesive layer 1 side.

[0095] The base film 1 in the structure (7) may be a PET film or the like. The transparent vapor deposition stretched film may be the same as that in the structure (4). At least one of the adhesive layers 1 and 2 is a cured coating film of the adhesive of the present invention. The sealant film may be the same as that in the structure (1). As in the structure (1), a printed layer described later may be provided on the surface of the base film 1 on the adhesive layer 1 side.

[0096] The base film 1 in the structure (8) may be a PET film or the like. The metal layer may be an aluminum foil or the like. At least one of the adhesive layers 1 and 2 is a cured coating film of the adhesive of the present invention. The sealant film may be the same as that in the structure (1). As in the structure (1), a printed layer described later may be provided on the surface of the base film 1 on the adhesive layer 1 side.

[0097] In the structures (9) and (10), the base film 1 may be a PET film or the like. The base film 2 may be a nylon film or the like. The metal layer may be an aluminum foil or the like. At least one of the adhesive layers 1, 2, and 3 is a cured coating film of the adhesive of the present invention. The sealant film may be the same as that in the structure (1). As in the structure (1), a printed layer, which will be described later, may be provided on the surface of the base film 1 on the adhesive layer 1 side.

[0098] When the laminate of the present invention contains at least one of a metal vapor deposition film, a transparent vapor deposition film, and a metal layer, the adhesive layer in contact with the metal vapor deposition layer, the transparent vapor deposition layer, and the metal layer is preferably a cured coating film of the adhesive of the present invention.

[0099] The adhesive of the present invention is usually used as a two-liquid adhesive. Therefore, it is preferable to mix the oil (A) containing an acid anhydride group with the curing agent (H) immediately before use. As described above, the compounding ratio is preferably in the range of 0.5 to 1.5, more preferably 0.8 to 1.25, in terms of the molar ratio of the acid anhydride group of (A) to the functional group reactive with the acid anhydride group of (H) (acid anhydride group / functional group reactive with acid anhydride group). If the compounding ratio of (A) to (H) is within the above range, a coating having excellent adhesive strength can be obtained. In addition, when the curing agent (H) contains an amine compound (C), the amount of (C) used is preferably in the range of 0.05 to 0.7, more preferably 0.1 to 0.5, in terms of the molar ratio of the nitrogen of (C) to the acid anhydride group of (A) (nitrogen / acid anhydride group). If the amount of (C) used is within the above range, an adhesive cured product having excellent adhesive strength can be obtained while ensuring a suitable pot life. When used as a two-component adhesive like this, the oil or fat containing an acid anhydride group (A) is sometimes referred to as the main component, and the hardener (H) as the hardener.

[0100] When the adhesive of the present invention is a solvent-based adhesive, the adhesive of the present invention is applied to a film material as a substrate using a roll such as a gravure roll, and the organic solvent is evaporated by heating in an oven or the like, and then the other substrate is laminated to obtain the laminate of the present invention. After lamination, it is preferable to carry out an aging treatment. The aging temperature is preferably room temperature to 80°C, and the aging time is preferably 12 to 240 hours.

[0101] When the adhesive of the present invention is a solventless type, the adhesive of the present invention, which has been preheated to about 40°C to 100°C, is applied to the film material as the substrate using a roll such as a gravure roll, and the other substrate is immediately laminated to obtain the laminate of the present invention. After lamination, it is preferable to carry out an aging treatment. The aging temperature is preferably room temperature to 70°C, and the aging time is preferably 6 to 240 hours.

[0102] When the adhesive of the present invention is used as an adhesion promoter, the adhesion promoter of the present invention is applied to a film material serving as a substrate using a roll such as a gravure roll, the organic solvent is evaporated by heating in an oven or the like, and then a molten polymer material is laminated using an extruder to obtain the laminate of the present invention.

[0103] The amount of adhesive to be applied is adjusted as appropriate. For example, in the case of a solvent-based adhesive, the solid content is 1 g / m 2 More than 10g / m 2 Less than 1 g / m 2 More than 5g / m 2 Adjust the amount of adhesive applied so that it is as follows: For a solvent-free adhesive, the amount of adhesive applied is, for example, 1 g / m 2 More than 10g / m 2 Less than 1 g / m 2 More than 5g / m 2 The following is the result.

[0104] When the adhesive of the present invention is used as an adhesive auxiliary, the coating amount is, for example, 0.03 g / m 2 More than 0.09g / m 2 The solid content is as follows:

[0105] (Printing layer) The printing layer is a layer on which characters, figures, symbols, and other desired patterns are printed. There is no particular limitation on the printing method or printing ink, and any known printing method or printing ink can be used. Printing inks using gravure printing, flexographic printing, lithographic offset printing, inkjet recording printing, and the like are often used for the film used as the substrate. Printing inks that combine these printing methods with methods of curing with active energy rays such as ultraviolet rays (UV), LEDs, and electron beams (EB), or methods of curing with heat, and the like, are also used. In addition, depending on the solvent used, they may be referred to as water-based inks or organic solvent-based inks.

[0106] Specific examples include gravure printing ink and flexographic printing ink (in some industries, gravure printing ink and flexographic printing ink are referred to as liquid printing ink), ultraviolet-curable ink for lithographic offset printing, electron-beam-curable ink for lithographic offset printing, ultraviolet-curable ink for inkjet recording and printing, and electron-beam-curable ink for inkjet recording and printing.

[0107] Among them, packaging materials that require recycling often have a printed layer using liquid ink such as gravure ink or flexographic ink. The laminate may be provided at any position. In this specification, liquid ink is a general term for solvent-based ink used in gravure printing or flexographic printing. It may be an ink that contains a resin, a colorant, and a solvent as essential components, or it may be a so-called clear ink that contains a resin and a solvent but does not substantially contain a colorant.

[0108] The resin used in the liquid ink is not particularly limited, and examples thereof include acrylic resin, polyester resin, styrene resin, styrene-maleic acid resin, maleic acid resin, polyamide resin, polyurethane resin, vinyl chloride-vinyl acetate copolymer resin, vinyl chloride-acrylic copolymer resin, ethylene-vinyl acetate copolymer resin, vinyl acetate resin, polyvinyl chloride resin, chlorinated polypropylene resin, cellulose-based resin, epoxy resin, alkyd resin, rosin-based resin, rosin-modified maleic acid resin, ketone resin, cyclized rubber, chlorinated rubber, butyral, petroleum resin, etc., and one or more of them can be used in combination. Preferably, at least one or two or more selected from polyurethane resin, vinyl chloride-vinyl acetate copolymer resin, and cellulose-based resin are used.

[0109] Colorants used in liquid inks include inorganic pigments such as titanium oxide, red iron oxide, antimony red, cadmium red, cadmium yellow, cobalt blue, Prussian blue, ultramarine, carbon black, and graphite; organic pigments such as soluble azo pigments, insoluble azo pigments, azo lake pigments, condensed azo pigments, copper phthalocyanine pigments, and condensed polycyclic pigments; and extender pigments such as calcium carbonate, kaolin clay, barium sulfate, aluminum hydroxide, and talc.

[0110] The organic solvent used in the liquid ink preferably does not contain an aromatic hydrocarbon-based organic solvent. More specifically, examples of the organic solvent include alcohol-based organic solvents such as methanol, ethanol, n-propanol, isopropanol, and butanol, ketone-based organic solvents such as acetone, methyl ethyl ketone, and methyl isobutyl ketone, ester-based organic solvents such as methyl acetate, ethyl acetate, propyl acetate, and butyl acetate, aliphatic hydrocarbon-based organic solvents such as n-hexane, n-heptane, and n-octane, and alicyclic hydrocarbon-based organic solvents such as cyclohexane, methylcyclohexane, ethylcyclohexane, cycloheptane, and cyclooctane, and these may be used alone or in combination of two or more.

[0111] (Primer layer) A primer layer can be provided to facilitate fixation of the printed layer to the plastic film substrate and to facilitate peeling of the printed layer in a treatment using an alkaline solution, which is currently the most widely used recycling treatment. A primer layer containing a urethane resin is particularly preferred as the primer layer.

[0112] <Urethane resin (A)> The urethane resin (PA) suitable for the primer layer used in the present invention is made of a reaction product obtained by reacting (crosslinking / curing reaction) an aromatic polyester polyol (a1) with a polyisocyanate (a2). The urethane resin (PA) may contain, in addition to the aromatic polyester polyol (a1) and the polyisocyanate (a2), another polyol (a3), or may be a reaction product of the aromatic polyester polyol (a1), the polyisocyanate (a2), and the other polyol (a3).

[0113] <<Aromatic polyester polyol (a1)>> The aromatic polyester polyol (a1) can be produced, for example, by subjecting an aromatic dicarboxylic acid (a1-1) and a polyol (a1-2) to an esterification reaction.

[0114] Examples of the aromatic dicarboxylic acid (a1-1) that can be used when producing the aromatic polyester polyol (a1) include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, orthophthalic 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, as well as their acid anhydrides or ester-forming derivatives; aromatic hydroxycarboxylic acids such as p-hydroxybenzoic acid and their ester-forming derivatives; and sulfonic acid group-containing aromatic dicarboxylic acids such as 5-sulfoisophthalic acid and their ester-forming derivatives.

[0115] In addition to the aromatic dicarboxylic acid (a1-1), an aliphatic carboxylic acid or an alicyclic carboxylic acid can be used in combination. For example, an aliphatic dicarboxylic acid such as succinic acid, succinic anhydride, adipic acid, suberic acid, azelaic acid, sebacic acid, dimer acid, maleic anhydride, or fumaric acid, an alicyclic dicarboxylic acid such as 1,4-cyclohexanedicarboxylic acid, or an anhydride or ester-forming derivative thereof can be used. These can be used alone or in combination of two or more kinds.

[0116] Examples of the polyol (a1-2) that can be used include ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, dipropylene glycol, 1,4-butanediol, 1,3-butanediol, 1,2-butanediol, 2,3-butanediol, 1,5-pentanediol, 1,5-hexanediol, 2,5-hexanediol, 1,6-hexanediol, 1,7-heptanediol, and neopentyl glycol.

[0117] Specifically, the aromatic dicarboxylic acid (a1-1) and the polyol (a1-2) can be reacted, if necessary, in the presence of a catalyst in a reaction vessel purged with an inert gas such as nitrogen under normal pressure or reduced pressure. The reaction is preferably carried out at a temperature in the range of 100°C to 300°C.

[0118] Examples of the catalyst that can be used include acetates of alkali metals or alkaline earth metals, and compounds containing zinc, manganese, cobalt, antimony, germanium, titanium, tin, zirconium, etc. Among these, it is preferable to use tetraalkyl titanates and tin oxalate, which are effective in transesterification reactions and polycondensation reactions.

[0119] When producing the urethane resin (PA), other polyols (a3) ​​and the like can also be used in combination with the aromatic polyester polyol (a1) and the polyisocyanate (a2).

[0120] As the other polyol (a3), polyols similar to the above polyol (a1-2) can be used, such as relatively low molecular weight polyols such as ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, dipropylene glycol, 1,4-butanediol, 1,3-butanediol, 1,2-butanediol, 2,3-butanediol, 1,5-pentanediol, 1,5-hexanediol, 2,5-hexanediol, 1,6-hexanediol, 1,7-heptanediol, and neopentyl glycol.

[0121] <<Polyisocyanate (a2)>> As the polyisocyanate (a2) that reacts with the polyol (a1) to form the urethane resin (PA), for example, aromatic diisocyanates such as phenylene diisocyanate, tolylene diisocyanate, diphenylmethane diisocyanate, and naphthalene diisocyanate, and aliphatic or alicyclic structure-containing diisocyanates such as hexamethylene diisocyanate, lysine diisocyanate, cyclohexane diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, xylylene diisocyanate, and tetramethylxylylene diisocyanate can be used alone or in combination of two or more. Among them, it is more preferable to use one or more selected from the group consisting of isophorone diisocyanate, tolylene diisocyanate, hexamethylene diisocyanate, and dicyclohexylmethane diisocyanate from the viewpoint of improving the adhesion to the substrate and the deinking property of the resulting primer layer.

[0122] The urethane resin (PA) can be produced, for example, in the absence of a solvent or in the presence of an organic solvent, by reacting the aromatic polyester polyol (a1), the polyisocyanate (a2), and, if necessary, the polyol (a3), and, if necessary, a chain extender. When the organic solvent is used, it is preferable to remove the organic solvent by a method such as distillation when dispersing the urethane resin (PA) in the aqueous medium (S).

[0123] Examples of organic solvents that can be used when producing the urethane resin (PA) include ketones such as acetone and methyl ethyl ketone; ethers such as tetrahydrofuran and dioxane; acetates such as ethyl acetate and butyl acetate; nitriles such as acetonitrile; dimethylformamide and N-methylpyrrolidone, which can be used alone or in combination of two or more.

[0124] The chain extender that can be used when producing the urethane resin (PA) can be used for the purpose of increasing the molecular weight of the urethane resin (PA) and improving the durability of the resulting film or the like. As a chain extender that can be used when producing the urethane resin (PA), polyamines and other compounds containing active hydrogen atoms can be used.

[0125] Examples of polyamines include diamines such as ethylenediamine, 1,2-propanediamine, 1,6-hexamethylenediamine, piperazine, 2,5-dimethylpiperazine, isophoronediamine, 4,4'-dicyclohexylmethanediamine, 3,3'-dimethyl-4,4'-dicyclohexylmethanediamine, and 1,4-cyclohexanediamine; N-hydroxymethylaminoethylamine, N-hydroxyethylaminoethylamine, N-hydroxypropylaminopropylamine, N-ethylaminoethylamine, and N-methylaminopropylamine; Benzene triamine, dipropylene triamine, triethylenetetramine; hydrazine, N,N'-dimethylhydrazine, 1,6-hexamethylenebishydrazine; succinic dihydrazide, adipic dihydrazide, glutaric dihydrazide, sebacic dihydrazide, isophthalic dihydrazide; β-semicarbazidopropionic hydrazide, 3-semicarbazido-propyl-carbazic acid ester, semicarbazido-3-semicarbazidomethyl-3,5,5-trimethylcyclohexane may be used, and it is preferable to use ethylenediamine.

[0126] Other active hydrogen-containing compounds that can be used include, for example, glycols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, hexamethylene glycol, neopentyl glycol, sucrose, methylene glycol, glycerin, and sorbitol; phenols such as bisphenol A, 4,4'-dihydroxydiphenyl, 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxydiphenyl sulfone, hydrogenated bisphenol A, and hydroquinone; and water.

[0127] The chain extender can be used when reacting the aromatic polyester polyol (a1) with the polyisocyanate (a2) or after the reaction. The chain extender can also be used when dispersing the urethane resin (PA) in the aqueous medium (S) to make it aqueous.

[0128] <<Characteristics of urethane resin (PA)>> The concentration of aromatic rings derived from raw material monomers of aromatic dicarboxylic acid (a1-1) in the urethane resin (PA) is 1 mmol / g or more. The aromatic ring concentration can be determined by calculating the number of moles of aromatic rings contained in 1 g of the urethane resin (PA). The specific calculation method will be described later. From the viewpoint of improving the adhesion to the substrate and deinking ability of the resulting primer layer, the aromatic ring concentration is preferably 1.5 mmol / g or more, and more preferably 2 mmol / g or more, and from the viewpoint of good film-forming properties of the primer layer, the aromatic ring concentration is preferably 6 mmol / g or less, and more preferably 5 mmol / g or less.

[0129] The ester bond concentration in the urethane resin (PA) is 1 mmol / g or more. The ester bond concentration is the percentage of ester bonds contained in 1 g of the urethane resin (PA). It can be determined by calculating the number of moles of the group. The specific calculation method will be described later. From the viewpoint of improving the adhesion to the substrate and the deinking ability of the obtained primer layer, the ester bond concentration is preferably 2 mmol / g or more, and more preferably 4 mmol / g or more, and from the viewpoint of good blocking resistance of the primer layer, the ester bond concentration is preferably 9 mmol / g or less, and more preferably 7 mmol / g or less.

[0130] The acid value of the urethane resin (PA) is 8 to 45 mg KOH / g. The acid value is the amount of acid in 1 g of resin calculated by titrating the acid with an alkali, converted into mg of potassium hydroxide, according to JIS K0070. If the acid value is 8 mgKOH / g or more, the aqueous dispersion stability can be improved, and is preferably 15 mgKOH / g or more, and more preferably 20 mgKOH / g or more.If the acid value is 45 mgKOH / g or less, the adhesion to the polyester substrate can be well ensured, and is preferably 40 mgKOH / g or less, and more preferably 30 mgKOH / g or less.

[0131] The value obtained by dividing the mass of the raw material monomer of the polyisocyanate (a2) contained in 1 g of the urethane resin (PA) by the NCO equivalent weight of the raw material monomer of the polyisocyanate (a2) is preferably 1.0 to 6.0 mmol / g. If the value is 1.0 mmol / g or more, the substrate adhesion and deinking property of the resulting primer layer can be improved, and it is more preferable that the value is 1.5 mmol / g or more, and more preferable that the value is 1.8 mmol / g or more. If the value is 6.0 mmol / g or less, the film-forming property of the primer layer can be ensured, and it is more preferable that the value is 5.0 mmol / g or less, and more preferable that the value is 4.0 mmol / g or less.

[0132] The weight average molecular weight of the urethane resin (PA) is preferably 10,000 to 100,000. From the viewpoints of blocking resistance to the substrate, hydrolysis resistance stability of the resin, etc., the weight average molecular weight of the urethane resin (PA) is preferably 20,000 or more, more preferably 30,000 or more. Moreover, from the viewpoints of low viscosity during aqueous dispersion, productivity, etc., the weight average molecular weight is preferably 80,000 or less, more preferably 60,000 or less.

[0133] In the present invention, the weight average molecular weight refers to a value measured by gel permeation chromatography (GPC) under the following conditions. Measurement equipment: High-speed GPC equipment (Tosoh Corporation "HLC-8220GPC") Column: The following columns manufactured by Tosoh Corporation were used in series connection. "TSKgelG5000" (7.8mmI.D. x 30cm) x 1 "TSKgelG4000" (7.8mmI.D. x 30cm) x 1 "TSKgelG3000" (7.8mmI.D. x 30cm) x 1 "TSKgelG2000" (7.8mmI.D. x 30cm) x 1 Detector: RI (differential refractometer) Column temperature: 40℃ Eluent: tetrahydrofuran (THF) Flow rate: 1.0mL / min Injection volume: 100 μL (sample concentration 0.4% by mass in tetrahydrofuran solution) Standard sample: Prepare a calibration curve using the following standard polystyrene.

[0134] [Standard polystyrene] "TSKgel Standard Polystyrene A-500" manufactured by Tosoh Corporation "TSKgel Standard Polystyrene A-1000" manufactured by Tosoh Corporation "TSKgel Standard Polystyrene A-2500" manufactured by Tosoh Corporation "TSKgel Standard Polystyrene A-5000" manufactured by Tosoh Corporation "TSKgel Standard Polystyrene F-1" manufactured by Tosoh Corporation "TSKgel Standard Polystyrene F-2" manufactured by Tosoh Corporation "TSKgel Standard Polystyrene F-4" manufactured by Tosoh Corporation "TSKgel Standard Polystyrene F-10" manufactured by Tosoh Corporation "TSKgel Standard Polystyrene F-20" manufactured by Tosoh Corporation "TSKgel Standard Polystyrene F-40" manufactured by Tosoh Corporation "TSKgel Standard Polystyrene F-80" manufactured by Tosoh Corporation "TSKgel Standard Polystyrene F-128" manufactured by Tosoh Corporation "TSKgel Standard Polystyrene F-288" manufactured by Tosoh Corporation "TSKgel Standard Polystyrene F-550" manufactured by Tosoh Corporation

[0135] The glass transition temperature of the urethane resin (PA) is preferably 0 to 110°C.

[0136] <Aqueous medium (S)> The urethane resin (PA) is preferably present in an aqueous medium. Examples of the aqueous medium (S) that serves as a solvent include water, organic solvents that are miscible with water, and mixtures thereof. Examples of organic solvents that are miscible with water include alcohols such as methanol, ethanol, n- and isopropanol; ketones such as acetone and methyl ethyl ketone; polyalkylene glycols such as ethylene glycol, diethylene glycol, and propylene glycol; alkyl ethers of polyalkylene glycol; and N-methyl-2-pyrrolidone. In the present invention, only water may be used, or a mixture of water and an organic solvent miscible with water may be used, or only an organic solvent miscible with water may be used. From the viewpoint of safety and environmental load, only water or a mixture of water and an organic solvent miscible with water is preferred, and only water is particularly preferred.

[0137] When dispersing the urethane resin (PA) in the aqueous medium (S), a machine such as a homogenizer can be used as necessary.

[0138] The aqueous urethane resin composition suitable for the primer layer used in the present invention contains urethane resin (PA) in the range of preferably 5% to 50% by mass, more preferably 10% to 25% by mass, based on the total amount of the aqueous urethane resin composition, and the aqueous medium (S) in the range of preferably 50% to 95% by mass, more preferably 75% to 90% by mass, based on the total amount of the urethane resin composition.

[0139] <Other additives> The aqueous urethane resin composition suitable for the primer layer used in the present invention may contain various additives, such as a film-forming assistant, a crosslinking agent, a curing accelerator, a plasticizer, an antistatic agent, a wax, a light stabilizer, a flow regulator, a dye, a leveling agent, a rheology control agent, an ultraviolet absorber, an antioxidant, a photocatalytic compound, an inorganic pigment, an organic pigment, and an extender pigment, as required.

[0140] Among the additives, the emulsifier and leveling agent may cause a decrease in the durability of the obtained film, etc., so when high durability is required for the film, etc., it is preferable to use them in an amount of 5 mass % or less based on the total amount of the aqueous urethane resin composition.

[0141] In addition, the aqueous urethane resin composition suitable for the primer layer used in the present invention can be used in combination with various crosslinking agents to form a film with excellent durability, etc. Examples of the crosslinking agent that can be used include isocyanate-based crosslinking agents, epoxy-based crosslinking agents, amino-based crosslinking agents, aziridine-based crosslinking agents, silane coupling agent-based crosslinking agents, carbodiimide-based crosslinking agents, and oxazolidine-based crosslinking agents. The crosslinking agent is preferably used in an amount of 30% by mass or less, and more preferably 20% by mass or less, based on the total amount of the urethane resin (PA) from the viewpoints of improving adhesion to the substrate, improving deinking properties, etc. The crosslinking agent is preferably mixed and used immediately before coating the aqueous urethane resin composition of the present invention.

[0142] (Primer layer) The aqueous urethane resin composition suitable for the primer layer used in the present invention can be applied onto the above-mentioned substrate to form a primer layer. The aqueous urethane resin composition of the present invention can be applied to a substrate by using a known printing method such as gravure printing, flexographic printing, etc. When printing, the composition is diluted with an aqueous solution, for example, a diluting solvent obtained by mixing water with an alcohol-based organic solvent such as ethyl alcohol, isopropyl alcohol, or normal propyl alcohol, to a viscosity and concentration suitable for the gravure printing method or the flexographic printing method, and is supplied to each printing unit either alone or in a mixture.

[0143] In addition, the method for applying the aqueous urethane resin composition onto a substrate can be an inline coating method in which the aqueous urethane resin composition is applied during a substrate stretching process (e.g., a biaxial stretching process) and then a further stretching process is performed, or an offline coating method in which the aqueous urethane resin composition is applied and dried after the substrate stretching process (e.g., a biaxial stretching process) to form a primer layer.

[0144] A printing layer made of a printing ink composition can be formed on the primer layer. The primer layer can be easily removed by treatment with an alkaline solution. Since the primer layer can be easily peeled off from the substrate, the printed layer formed on the primer layer can also be easily removed from the substrate.

[0145] (other layers) In the laminate of the present invention, in applications that do not require recycling, in addition to the above-mentioned laminates (1) to (10), other films and substrates may be included. As the other substrates, in addition to the above-mentioned stretched films, unstretched films, and transparent vapor deposition films, porous substrates such as paper, wood, and leather, which will be described later, can also be used. The adhesive used when bonding the other substrates may be the adhesive of the present invention or may not be the adhesive.

[0146] The paper can be made of any known paper base material without any particular limitation. Specifically, the paper is made by a known paper machine using natural fibers for papermaking such as wood pulp, 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 obtained by chemically modifying these pulps. As the type of pulp, chemical pulp, ground pulp, chemi-ground pulp, thermomechanical pulp, etc., made by sulfate cooking method, acidic / neutral / alkaline sulfite cooking method, soda salt cooking method, etc., can be used.

[0147] In addition, various commercially available high-quality papers, coated papers, backing papers, impregnated papers, cardboards, paperboards, and the like can also be used. Furthermore, a printed layer may be provided on the outer or inner surface of the paper layer, if necessary.

[0148] The laminate of the present invention can be suitably used for various applications, such as packaging materials for food, medicines, and daily necessities; paper tableware such as lid materials, paper straws, paper napkins, paper spoons, paper plates, and paper cups; wall materials, roofing materials, solar cell panel materials, packaging materials for batteries, window materials, outdoor flooring materials, lighting protection materials, automotive parts, signs, stickers, and other outdoor industrial applications; decorative sheets used in simultaneous injection molding decoration methods, and packaging materials for liquid laundry detergents, liquid kitchen detergents, liquid bath detergents, liquid bath soaps, liquid shampoos, liquid conditioners, and the like.

[0149] <Packaging material> The laminate of the present invention can be used as a multi-layer packaging material for protecting foods, medicines, etc. When used as a multi-layer packaging material, the layer structure can be changed depending on the contents, the environment of use, and the form of use. In addition, the packaging material of the present invention may be appropriately provided with an easy-opening treatment or a resealing means.

[0150] The packaging material of the present invention is obtained by using the laminate of the present invention, overlapping the surfaces of the sealant films of the laminates so that they face each other, and then heat-sealing the peripheral edge to form a bag. Examples of the bag-making method include folding or overlapping the laminate of the present invention so that the surfaces of the inner layers (the surfaces of the sealant films) face each other, and heat-sealing the peripheral edge, for example, by a side seal type, a two-sided seal type, a three-sided seal type, a four-sided seal type, an envelope seal type, a grooving seal type, a pleated seal type, a flat bottom seal type, a square bottom seal type, a gusset type, or other heat seal type. The packaging material of the present invention can take various forms depending on the contents, the environment of use, and the form of use. Self-supporting packaging materials (standing pouches) are also possible. Heat sealing can be performed by known methods such as bar seal, rotary roll seal, belt seal, impulse seal, high frequency seal, and ultrasonic seal.

[0151] The packaging material of the present invention is filled with contents through its opening, and the opening is then heat-sealed to produce a product using the packaging material of the present invention. The contents to be filled include, for example, foods such as rice crackers, bean snacks, nuts, biscuits, cookies, wafers, marshmallows, pies, semi-dried cakes, candies, snacks, and other confectioneries, bread, snack noodles, instant noodles, dried noodles, pasta, aseptically packaged cooked rice, porridge, porridge, packaged rice cakes, and cereal foods, and other staple foods, pickles, boiled beans, natto, miso, frozen tofu, tofu, nametake mushrooms, konjac, wild vegetable processed products, jams, peanut cream, salads, frozen vegetables, and potato processed products, livestock processed products such as hams, bacon, sausages, chicken processed products, and corned beef, and fish hams, These include processed seafood products such as sausages, fish paste products, kamaboko, nori, tsukudani, bonito flakes, shiokara, smoked salmon, and spicy cod roe; fruit pulp such as peaches, mandarin oranges, pineapples, apples, pears, and cherries; vegetables such as corn, asparagus, mushrooms, onions, carrots, radishes, and potatoes; cooked foods such as hamburger steaks, meatballs, seafood fries, gyoza, croquettes, and other frozen and chilled prepared foods; dairy products such as butter, margarine, cheese, cream, instant creamy powder, and infant formula; liquid seasonings, retort curry, and pet food.

[0152] In addition, the composition can be used as a packaging material for various non-food items, such as tobacco, disposable hand warmers, medicines such as infusion packs, liquid laundry detergent, liquid kitchen detergent, liquid bath detergent, liquid bath soap, liquid shampoo, liquid conditioner, cosmetics such as lotion and milky lotion, vacuum insulation materials, batteries, etc.

[0153] (Method for separating and recovering laminate) The laminate of the present invention can be separated into its respective substrates and recovered by treatment using an alkaline solution, which is currently the most widely used recycling treatment. For example, the laminate can be immersed in an alkaline solution while being heated and stirred at 20 to 90° C., whereby the laminate can be separated and recovered.

[0154] The alkaline solution used in the separation and recovery method is preferably an aqueous sodium hydroxide solution, an aqueous potassium hydroxide solution, etc. The aqueous sodium hydroxide solution or the aqueous potassium hydroxide solution has a concentration of preferably 0.5% by mass to 10% by mass, and more preferably 1% by mass to 5% by mass. The pH is preferably 10 or more.

[0155] The alkaline solution may also contain a water-soluble organic solvent. Examples of the water-soluble organic solvent include methyl alcohol, ethyl alcohol, propyl alcohol, isopropyl alcohol, ethylene glycol monomethyl ether (methyl cellosolve), ethylene glycol monoethyl ether (cellosolve), ethylene glycol monobutyl ether (butyl cellosolve), ethylene glycol dibutyl ether, diethylene glycol monomethyl ether (methyl carbitol), diethylene glycol dimethyl ether, diethylene glycol monoethyl ether (carbitol), diethylene glycol diethyl ether (diethyl carbitol), diethylene glycol monobutyl ether (butyl carbitol), diethylene glycol dibutyl ether, triethylene glycol monomethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, methylene dimethyl ether (methylal), propylene glycol monobutyl ether, tetrahydrofuran, acetone, diacetone alcohol, acetonyl acetone, acetyl acetone, ethylene glycol monomethyl ether acetate (methyl cellosolve acetate), and diethylene glycol monomethyl ether acetate (methyl carbitol acetate). Examples of such an acidic monomer include diethylene glycol monoethyl ether acetate (carbitol acetate), ethyl hydroxyisobutyrate, and ethyl lactate, which may be used alone or in combination of two or more kinds.

[0156] The content of the water-soluble organic solvent in the alkaline solution is preferably 30% by mass to 70% by mass, and more preferably 40% by mass to 60% by mass.

[0157] The alkaline solution may also contain a water-insoluble organic solvent. Specific examples of the water-insoluble organic solvent include alcohol solvents such as n-butanol, 2-butanol, isobutanol, and octanol, aliphatic hydrocarbon solvents such as hexane, heptane, and normal paraffin, aromatic hydrocarbon solvents such as benzene, toluene, xylene, and alkylbenzene, halogenated hydrocarbon solvents such as methylene chloride, 1-chlorobutane, 2-chlorobutane, 3-chlorobutane, and carbon tetrachloride, ester solvents such as methyl acetate, ethyl acetate, and butyl acetate, ketone solvents such as methyl isobutyl ketone, methyl ethyl ketone, and cyclohexanone, and ether solvents such as ethyl ether and butyl ether, which may be used alone or in combination of two or more.

[0158] The alkaline solution may contain a surfactant, such as various anionic surfactants, nonionic surfactants, cationic surfactants, and amphoteric surfactants, of which anionic surfactants and nonionic surfactants are preferred.

[0159] Examples of the anionic surfactant include alkylbenzenesulfonates, alkylphenylsulfonates, alkylnaphthalenesulfonates, higher fatty acid salts, sulfate salts of higher fatty acid esters, sulfonates of higher fatty acid esters, sulfate salts and sulfonates of higher alcohol ethers, higher alkyl sulfosuccinates, polyoxyethylene alkyl ether carboxylates, polyoxyethylene alkyl ether sulfates, alkyl phosphates, and polyoxyethylene alkyl ether phosphates. Specific examples of these include dodecylbenzenesulfonates, isopropylnaphthalenesulfonates, monobutylphenylphenol monosulfonates, monobutylbiphenylsulfonates, and dibutylphenylphenol disulfonates.

[0160] Examples of nonionic surfactants include polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl ethers, polyoxyethylene fatty acid esters, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene sorbitol fatty acid esters, glycerin fatty acid esters, polyoxyethylene glycerin fatty acid esters, polyglycerin fatty acid esters, sucrose fatty acid esters, polyoxyethylene alkylamines, polyoxyethylene fatty acid amides, fatty acid alkylol amides, alkyl alkanol amides, acetylene glycol, oxyethylene adducts of acetylene glycol, polyethylene glycol polypropylene glycol block copolymers, and the like. Among these, polyoxyethylene nonylphenyl ether, polyoxyethylene octylphenyl ether, polyoxyethylene dodecylphenyl ether, polyoxyethylene alkyl ethers, polyoxyethylene fatty acid esters, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, fatty acid alkylol amides, acetylene glycol, oxyethylene adducts of acetylene glycol, and polyethylene glycol polypropylene glycol block copolymers are preferred.

[0161] Other surfactants that can be used include silicone surfactants such as polysiloxane oxyethylene adducts; fluorine-based surfactants such as perfluoroalkyl carboxylates, perfluoroalkyl sulfonates, and oxyethylene perfluoroalkyl ethers; and biosurfactants such as spiculisporic acid, rhamnolipids, and lysolecithin.

[0162] These surfactants can be used alone or in combination of two or more. When a surfactant is added, the amount of the surfactant added is preferably in the range of 0.001 to 2 mass %, more preferably 0.001 to 1.5 mass %, and even more preferably 0.01 to 1 mass %, based on the total amount of the alkaline solution.

[0163] The target laminate is immersed in the alkaline solution, for example in a treatment tank, in a state where the alkaline solution is heated to 20 to 90°C. At this time, heating or ultrasonic waves may be applied. There is no particular limitation on the heating method, and known heating methods using heat rays, infrared rays, microwaves, etc. may be used. In addition, ultrasonic vibration may be applied, for example, by attaching an ultrasonic vibrator to the treatment tank and applying ultrasonic vibration to the alkaline solution.

[0164] The alkaline solution is preferably stirred during the immersion. Examples of the stirring method include a method of mechanically stirring the dispersion of the laminate contained in the treatment tank with a stirring blade, a method of water flow stirring with a water flow pump, and a method of bubbling with an inert gas such as nitrogen gas. The above-mentioned methods may be used in combination to efficiently peel off the multilayer film.

[0165] The time for immersing the laminate in the alkaline solution varies depending on the structure of the laminate, but is generally in the range of 2 minutes to 48 hours. If the immersion time is less than 2 minutes, the adhesive layer may not completely peel off from the laminate and may remain partially. The number of times for immersing in the alkaline solution may be one time or several times.

[0166] In most cases, the laminate is provided with a printed ink layer for displaying the trade name and the like and for providing decorativeness in addition to the adhesive, but the printed ink layer can also be peeled off or dissolved in the step of immersing in the alkaline solution. In some cases, a metal foil or a vapor-deposited film such as aluminum is laminated, but in the present invention, the metal foil or vapor-deposited film can also be peeled off or dissolved.

[0167] It is presumed that the alkaline solution used in the separation and recovery method acts on the interface between the laminate and the adhesive or printing ink, significantly reducing the adhesive strength, thereby causing interfacial peeling between the laminate and the adhesive or printing ink. Normally, a coating film after crosslinking of a reactive adhesive or the like hardly dissolves in any solution, but in the present invention, it is not dissolved but rather causes interfacial peeling, so it is presumed that efficient separation and recovery can be performed in a short time.

[0168] (Recycled plastics) The laminate of the present invention can be separated into each substrate as described above, or the laminate or packaging of the present invention can be processed directly by various known recycling plastic processing methods to produce recycled plastic. As an example of a specific embodiment, recycled plastic can be obtained by a production method including a step of crushing the laminate of the present invention separated into each substrate, or the laminate or packaging of the present invention, a step of melting and kneading the crushed film pieces, and a step of pelletizing the melted and kneaded mixture.

[0169] The crusher used for crushing (grinding) is not particularly limited and any known crusher may be used. The crushed film pieces are physically blended by melt kneading, solvent cast blending, latex blending, polymer complex, etc. In particular, the melt kneading method is common. Examples of kneading devices include tumblers, Henschel mixers, rotary mixers, super mixers, ribbon tumblers, V blenders, etc. The film pieces are melt kneaded by such kneading devices and then pelletized. A single-screw or multi-screw extruder is generally used for melt kneading pelletization, and the film pieces may be charged as they are, or may be charged after being compressed and reduced in volume with or without heating. In addition to these extruders, Banbury mixers, rollers, co-kneaders, blast mills, Prabender blastographs, etc. can also be used, which are operated batchwise or continuously. Alternatively, the film pieces may be used as molding resins and melt kneaded in the heating cylinder of a molding machine without melt kneading. EXAMPLES

[0170] The contents and effects of the present invention will be described in more detail below with reference to examples. In the examples, "parts" refers to "parts by mass."

[0171] Production Example 1 [Synthesis of fats and oils containing acid anhydride groups (A-1)] In a flask equipped with a stirrer, a thermometer, and a nitrogen gas inlet tube, 1,000 parts of tung oil was charged and heated to 100° C. Next, 250 parts of maleic anhydride was added in five portions, and the mixture was allowed to react for another 3 hours to obtain an oil (A-1) containing an acid anhydride group.

[0172] Production Example 2 [Synthesis of fats and oils containing acid anhydride groups (A-2)] In a flask equipped with a stirrer, a thermometer, and a nitrogen gas inlet tube, 1000 parts of linseed oil and 100 parts of maleic anhydride were charged and heated to 180° C. After reacting at 180° C. for 2 hours, 125 parts of maleic anhydride was added, and the mixture was heated to 200° C. and further reacted for 3 hours to obtain an oil (A-2) containing an acid anhydride group.

[0173] Production Example 3 [Synthesis of fats and oils containing acid anhydride groups (A-3)] In a flask equipped with a stirrer, a thermometer, and a nitrogen gas inlet tube, 800 parts of soybean oil, 225 parts of maleic anhydride, and 0.5 parts of phosphoric acid were charged and heated to 180° C. After reacting at 180° C. for 3 hours, the temperature was lowered to 100° C., 200 parts of tung oil was added, and the reaction was continued for another 3 hours to obtain an oil (A-3) containing an acid anhydride group.

[0174] Production Example 4 [Synthesis of polyester polyol (B3-1)] In a polyester reaction vessel equipped with a stirrer, thermometer, nitrogen gas inlet tube, rectification tube, water separator, etc., 124 parts of ethylene glycol, 216 parts of diethylene glycol, 150 parts of neopentyl glycol, 590 parts of adipic acid, 70 parts of "Tsuno Dim 216" (a mixture of monool, diol, and triol of dimer acid, mainly composed of dimer acid diol, manufactured by Tsuno Food Industry Co., Ltd.), and 0.1 parts of tetraisopropyl titanate were charged, and the temperature at the top of the rectification tube was gradually heated so as not to exceed 100°C, and the internal temperature was maintained at 240°C. When the acid value became 2.0 (mg-KOH / g) or less, the esterification reaction was terminated, and polyester polyol (B3-1) was obtained. The hydroxyl value was 149 (mg-KOH / g).

[0175] Production Examples 5 to 6 [Synthesis of polyester polyols (B3-2) to (B3-3)] Except for changing the raw materials used as shown in Table 1, the same procedure as in Production Example 4 was carried out to obtain polyester polyols (B3-2) to (B3-3).

[0176] [Table 1]

[0177] In Table 1, blank spaces indicate no blend.

[0178] Production Example 7 [Synthesis of acid-modified polyester polyol (B-1)] In a polyester reaction vessel equipped with a stirrer, a thermometer, a nitrogen gas inlet tube, a rectification tube, etc., 1000 parts of the polyester polyol (B3-1) obtained in Production Example 4 and 20 parts of trimellitic anhydride were charged and reacted at an internal temperature of 170° C. for 4 hours to obtain an acid-modified polyester polyol (B-1). The hydroxyl value was 141 (mg-KOH / g) and the acid value was 13.3 (mg-KOH / g).

[0179] Production Examples 8 to 9 [Synthesis of Acid-Modified Polyester Polyols (B-2) to (B-3)] Except for changing the raw materials used as shown in Table 2, the same procedures as in Production Example 7 and Production Example 4 were carried out to obtain polyester polyols (B-2) to (B-3).

[0180] [Table 2]

[0181] Production Example 10 [Preparation Examples of Curing Agents (H-2) to (H-5) and (H-H1)] Various compounds were mixed in the ratios shown in Table 3 to prepare curing agents (H-2) to (H-5) and a comparative curing agent (H-H1).

[0182] [Table 3]

[0183] In Table 3, blanks indicate that no compound was used. The abbreviations are as follows: PK-400GD: Sannix PK-400GD (Sanyo Chemical Industries, Ltd., bifunctional polypropylene glycol, molecular weight 417) Gly: Glycerin T-403: Jeffamine T-403 (Huntsman (USA) trifunctional polyether polyamine, molecular weight 440) EDP-300: Adeka Polyether EDP-300 (Adeka Corporation, polypropylene glycol containing two tertiary amines in the molecule, molecular weight 300, OHV 750) EDP-450: Adeka Polyether EDP-450 (Adeka Corporation, polypropylene glycol containing two tertiary amines in the molecule, molecular weight 450, OHV 500)

[0184] Production Example 11 [Synthesis of polyisocyanate compound (E)] A flask equipped with a stirrer, a thermometer, and a nitrogen gas inlet tube was charged with 50 parts of Lupranate MI (a 50 / 50 mixture of 4,4'-diphenylmethane isocyanate and 2,4-diphenylmethane diisocyanate manufactured by BASF INOAC Polyurethanes) and heated to 60°C. 50 parts of a 20 / 30 (weight ratio) mixture of polypropylene glycol with a molecular weight of 1000 and polypropylene glycol with a molecular weight of 2000 was gradually added in four portions, and the mixture was then heated to 80°C and reacted for another 5 hours to obtain a polyisocyanate compound (E). The NCO% of the obtained polyisocyanate compound (E) was 13.8%.

[0185] Production Example 12 [Synthesis of polyurethane resin (PU) for deinking primer] In a polyester reaction vessel equipped with a stirrer, a thermometer, a nitrogen gas inlet tube, a distillation tube, etc., 320 g of terephthalic acid, 320 parts of isophthalic acid, 130 parts of ethylene glycol, and 230 parts of diethylene glycol were charged, and the temperature at the top of the distillation tube was gradually heated so that it did not exceed 100°C, and the internal temperature was maintained at 240°C. When the acid value became 2.0 (mg-KOH / g) or less, the esterification reaction was terminated to obtain a polyester polyol (P). The aromatic ring concentration was 3.8 mmol / g, the ester bond group concentration was 8.9 mmol / g, and the hydroxyl value was 49 (mg-KOH / g). Next, 740 parts of polyester polyol (P), 200 parts of isophorone diisocyanate, and 60 parts of 2,2'-dimethylolpropionic acid were charged into a four-neck flask equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen gas inlet tube, and the mixture was reacted at 75°C for 8 hours under a nitrogen stream to obtain a polyurethane resin (PU). In the polyurethane resin (PU), the aromatic ring concentration derived from the raw material monomer of aromatic dicarboxylic acid was 2.8 mmol / g, the ester bond group concentration was 6.6 mmol / g, and the acid value was 25 mg KOH / g. Ammonia was used as a neutralizing agent, and the mixture was neutralized to a neutralizing agent / acid equivalent ratio of 1.05, and then diluted with water to obtain an aqueous dispersion of polyurethane resin.

[0186] (Method of manufacturing the composition for primer layer) The composition for the primer layer was prepared by mixing 100 parts of the urethane resin (PU) with 3 parts of "Bayhydur Ultra BU3100" manufactured by Covestro, and then diluting the mixture with isopropyl alcohol (IPA) to a solid content of 10%.

[0187] (Method of manufacturing substrate with primer layer) The primer layer composition was printed on a stretched polypropylene (sometimes abbreviated as OPP) film that had been gravure-printed solidly with white printing ink (DIC's "Finart R794 White") using a gravure printing machine (manufactured by DIC Engineering Co., Ltd.) equipped with a gravure plate having a plate depth of 22 μm. The film was then dried at 100° C. for 10 minutes and then left at room temperature for 1 day to obtain a substrate 1 with a primer layer.

[0188] Examples and Comparative Examples (Examples 1 to 6 and Comparative Examples 1 to 3) According to the formulations in Tables 4 and 5, an oil or fat (A) containing an acid anhydride group and a curing agent (H) were blended to prepare adhesive compositions, and various evaluations were performed.

[0189] (Method of manufacturing laminate) (1) Manufacturing method of OPP / CPP laminate Using a laminator with a lamination speed set to 250 m / min, each prepared adhesive composition was applied to an oriented polypropylene (sometimes abbreviated as OPP) film that had been gravure-printed solidly with white printing ink (DIC "Finart R794 White") at a coating amount of 1.8 g / m2 solids. 2 A laminate was produced by laminating an OPP film / white printing ink layer / adhesive layer / CPP film layer by applying the coating so that the thickness of the coating was approximately 100 μm, laminating it with a non-oriented polypropylene (sometimes abbreviated as CPP) film, and curing it at 40°C for 4 days. This structure is abbreviated as OPP / CPP. (2) Manufacturing method of substrate 1 / CPP laminate Using a laminator with a lamination speed set to 250 m / min, each prepared adhesive composition was applied to the substrate 1 in an amount of 1.8 g / m2 (solid content). 2 A laminate was produced by laminating a substrate 1 / white printing ink layer / adhesive layer / CPP film layer by applying the coating so that the thickness of the coating was approximately 100 μm, laminating the substrate with a non-oriented polypropylene (sometimes abbreviated as CPP) film, and curing the substrate at 40° C. for 4 days. This structure is abbreviated as substrate 1 / CPP. (3) Manufacturing method of NK / PBS laminate Using a laminator with a lamination speed set to 250 m / min, each prepared adhesive composition was applied to Naturflex NK (a biodegradable film manufactured by Futamura Chemical Co., Ltd.) in an amount of 1.8 g / m2 solids. 2 The adhesive was applied so that the thickness of the adhesive layer was approximately 100 μm, and the adhesive layer was laminated with a PBS film (polybutylene succinate, manufactured by Mitsubishi Chemical Corporation) and cured at 40° C. for 4 days to produce a laminate consisting of Naturflex NK / adhesive layer / PBS film layer. This structure is abbreviated as NK / PBS. (4) Manufacturing method of the film for biodegradability evaluation Using a laminator with a lamination speed set to 250 m / min, each prepared adhesive composition was applied onto a polyethylene terephthalate film in an amount of 1.8 g / m2 (solid content). 2 The coating was then cured at 40°C for 4 days to prepare a film for evaluating biodegradability.

[0190] (Adhesive strength) The obtained laminate was aged at 40° C. for 4 days, and then a test piece having a width of 15 mm was prepared and the T-peel strength was measured at 25° C. and a peel rate of 300 mm / min. 4: Adhesive strength>1.2N 3: Adhesive strength 0.8~1.2N (practical level) 2: Adhesive strength 0.5~0.8N 1: Adhesive strength <0.5N

[0191] (Recycling test) Test pieces measuring 2 cm x 2 cm were cut from the laminates of OPP / CPP configuration for Examples 1 to 4, and from the laminates of Base material 1 / CPP configuration for Examples 5 and 6. The test pieces were immersed in 50 g of an alkaline solution of 2% sodium hydroxide at 70°C (the solvent for the alkaline solution is shown in the table) and stirred at 400 rpm. The time it took for each laminate to peel off and whether or not the adhesive layer peeled off from the CPP film were measured.

[0192] (Laminate peeling) 5: Peeled off within 15 minutes (very good) 4: Peeled off within 30 minutes (Excellent) 4 or above is desirable 3: Peeled off within 1 hour 2: Peeled off within 2 hours 1: No peeling even after 2 hours

[0193] (Peeling of adhesive layer) The adhesive was evaluated based on the ratio of adhesive remaining on the CPP film (residual rate). The residual rate of adhesive was calculated by measuring the IR of the film after the test with FT-IR and calculating the height of the absorption peak of the ester bond at 1740 cm-1 based on the IR measurement result of the film before the test. 5: Less than 5% (Excellent) 4:5~20% (practical level) 3: 20-60% (not suitable for practical use) 2: 60~80% 1:>80%

[0194] (biodegradable) Compost decomposition was measured using the biodegradability evaluation film according to a method in accordance with JIS K6953-1:2011. *Culture temperature: 58℃, culture period: 28 days *Evaluation criteria: 5: Compost decomposition rate of 50% or more 4: Compost decomposition rate is between 40% and 50% 3: Compost decomposition rate is between 25% and 40% 2: Compost decomposition rate: 15% to 25% (lower practical limit) 1: Compost decomposition rate is less than 15% (not suitable for practical use)

[0195] The results are shown in Tables 4 and 5.

[0196] [Table 4]

[0197] [Table 5]

[0198] As a result, Examples 1 to 6 not only had the necessary adhesive strength, but also had excellent releasability and biodegradability, whereas the Comparative Example was inferior in both releasability and biodegradability.

Claims

1. A biodegradable adhesive composition comprising an oil (A) containing an acid anhydride group and a curing agent (H), the curing agent (H) containing an acid-modified polyester polyol having an acidic group in the polyol molecule obtained by adding trimellitic anhydride to the hydroxyl group of a polyester polyol, and a tertiary amine-containing polyol.

2. 2. The biodegradable adhesive composition according to claim 1, wherein the oil (A) containing an acid anhydride group is a maleic anhydride modified vegetable oil (A1).

3. The biodegradable adhesive composition according to claim 1, wherein the blending ratio of the oil (A) containing an acid anhydride group to the curing agent (H) is in the range of 0.5 to 1.5 in terms of the molar ratio of the acid anhydride group of the oil (A) containing an acid anhydride group to the functional group reactive with the acid anhydride group of the curing agent (H) (acid anhydride group / functional group reactive with an acid anhydride group).

4. A laminate comprising a first substrate, an adhesive layer, and a second substrate laminated in this order, the adhesive layer being a biodegradable adhesive composition according to any one of claims 1 to 3.

5. 5. The laminate according to claim 4, wherein the first substrate or the second substrate is made of a urethane resin (PA) which is a reaction product of an aromatic polyester polyol (a1) containing an aromatic dicarboxylic acid (a1-1) as a raw material monomer and a polyisocyanate (a2), the urethane resin (PA) having an aromatic ring concentration derived from the raw material monomer of the aromatic dicarboxylic acid (a1-1) of 1 mmol / g or more, the urethane resin (PA) having an ester bond group concentration of 1 mmol / g or more, and the urethane resin (PA) having an acid value of 8 to 45 mgKOH / g, and a primer layer and a printed layer containing the urethane resin.

6. A packaging material obtained by forming the laminate according to claim 4 into a bag shape.

7. A packaging material obtained by forming the laminate according to claim 5 into a bag shape.

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