Two-component curable adhesive, laminate, packaging material

Abstract

Provided are: a two-part curable adhesive which contains a polyol composition (X) containing a polyester polyol compound (A), and also contains a polyisocyanate composition (Y) containing a polyisocyanate compound (B), wherein the number-average molecular weight of the polyester polyol compound (A) is within the range of 500-20,000, and one or more compounds among the polyester polyol compound (A) and the polyisocyanate compound (B) are a reaction product of an aliphatic alcohol which has a quaternary carbon atom and a hydroxyl group having a valance of three or higher; a multilayer body; and a package.

Description

Technical Field

[0001] The present invention relates to a two-component curable adhesive for lamination, and to a laminate and a packaging material that are biodegradable and recyclable with an alkaline treatment solution.

Background Art

[0002] Since many synthetic resins do not easily decompose in the natural environment, the deterioration of the natural environment due to synthetic resins has become a problem. For example, discarded synthetic resins are broken or scraped by the sun's ultraviolet rays and waves in the ocean, and ultimately become microplastics, destroying and polluting the environment of marine animals and plants. In response to the social problem of global environmental degradation caused by the large-scale disposal of such synthetic resins, there is an increasing demand for sustainable product groups (packaging materials, films, etc.) made of recyclable materials or resins that are biodegradable in any environment (seawater, fresh water, soil, compost, etc.).

[0003] Conventional general packaging materials are often multi-layer laminates of a metal foil such as an aluminum foil or a metal vapor deposition film and a plastic film such as polyethylene, polypropylene, vinyl chloride, polyester, or nylon, using a two-component curable adhesive for lamination composed of a polyol composition and a polyisocyanate composition (see, for example, Patent Document 1). Not only plastic films, but also polyols, polyisocyanates, or their cured products are all synthetic resins. It is urgent to separate and reuse the synthetic resins in these wastes, or to devise ways to impart degradability (biodegradability) in the natural environment.

[0004] On the other hand, currently, whether to separate and reuse synthetic resins in waste, or to bury them in the soil expecting biodegradability, varies depending on the operation by countries and local governments. Furthermore, consumers who use packaging materials often discard the laminated packaging materials after use without judging whether they are recyclable or biodegradable. Therefore, there is a demand for laminated packaging materials that are recyclable and biodegradable.

[0005] As a two-component curable adhesive for laminates composed of a biodegradable polyol composition and a polyisocyanate composition, for example, a polyester polyol (AB) which is a reaction product of a hydroxyl group component (A) containing a diol (a) having a branched structure and a carboxylic acid component (B) containing an aliphatic dicarboxylic acid (b) having 2 to 12 carbon atoms and having a specific number average molecular weight, an adhesive containing a polyester polyol which is a polymer of lactide (C) and a cyclic monomer (D) is known (see, for example, Patent Document 2).

[0006] As a method for separating and recovering a laminated film capable of easily separating a laminated film laminated with a reactive adhesive mixed in plastic-based composite waste into a single-layer film, for example, it is known to contain a compound having an acidic group in the reactive adhesive used (see, for example, Patent Document 3).

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0008] The problem to be solved by the present invention is to provide a two-component curable adhesive for laminates, a laminate having biodegradability and recyclability with an alkali treatment liquid, and a packaging material, which have sufficient performance as a laminate adhesive for packaging materials, and are excellent in biodegradability and detachability when immersed in an alkaline aqueous solution.

Means for Solving the Problems

[0009] The inventors have found that a two-component curable adhesive containing a polyol composition (X) containing a specific polyester polyol compound (A) and a polyisocyanate composition (Y) containing a polyisocyanate compound (B) solves the above problems.

[0010] That is, the present invention provides a two-component curable adhesive containing a polyol composition (X) containing a polyester polyol compound (A) and a polyisocyanate composition (Y) containing a polyisocyanate compound (B), wherein the number average molecular weight of the polyester polyol compound (A) is in the range of 500 to 20,000, and either or both of the polyester polyol compound (A) and the polyisocyanate compound (B) are reaction products of an aliphatic alcohol having a quaternary carbon atom and having a hydroxyl group with a valence of 3 or more.

[0011] The present invention also provides a laminate including a first substrate, a second substrate, and an adhesive layer disposed between the first substrate and the second substrate, wherein the adhesive layer is a cured coating film of the two-component curable adhesive described above.

[0012] The present invention also provides a packaging material using the laminate described above.

[0013] The present invention also provides a method for recycling a laminate, including a step of immersing a laminate including a first substrate, a second substrate, and an adhesive layer disposed between the first substrate and the second substrate, wherein the adhesive layer is a cured coating film of the two-component curable adhesive described above, in a peeling liquid to separate the laminate into each layer, and a step of recovering each separated layer.

Effects of the Invention

[0014] According to the present invention, it is possible to provide a two-component curable adhesive for laminating, which has sufficient performance as a laminate adhesive for packaging materials, is excellent in biodegradability and removability when immersed in an aqueous alkali solution, and a biodegradable and recyclable laminate obtained using the adhesive can be provided by an alkali treatment liquid.

Mode for Carrying Out the Invention

[0015] <Adhesive> The adhesive of the present invention is a two-component curable adhesive containing a polyol composition (X) containing a polyester polyol compound (A) and a polyisocyanate composition (Y) containing a polyisocyanate compound (B), wherein the number average molecular weight of the polyester polyol (A) is in the range of 500 to 20,000, and either or both of the polyester polyol compound or the polyisocyanate compound (B) is a reaction product of an aliphatic alcohol having a quaternary carbon atom and having a hydroxyl group of trivalent or higher. Hereinafter, the adhesive of the present invention will be described in detail.

[0016] (Polyol Composition (X)) (Polyester Polyol Compound (A)) The polyol composition (X) used in the adhesive of the present invention contains a polyester polyol compound (A).

[0017] The polyester polyol compound (A) has a number average molecular weight in the range of 500 to 20,000. Being in this range provides excellent degradability under composting conditions. Among them, the range of 2000 to 10000 is still more preferable. The number average molecular weight in this specification is a value measured by gel permeation chromatography (GPC) under the following conditions.

[0018] Measuring device: HLC-8320GPC manufactured by Tosoh Corporation Column: TSKgel 4000HXL, TSKgel 3000HXL, TSKgel 2000HXL, TSKgel 1000HXL manufactured by Tosoh Corporation Detector: RI (Differential Refractometer) Data processing: Multi-station GPC-8020modelII manufactured by Tosoh Corporation Measuring conditions: Column temperature 40°C Solvent: Tetrahydrofuran Flow rate: 0.35 ml / min Standard; Monodisperse polystyrene Sample; A 0.2 mass% tetrahydrofuran solution in terms of resin solid content, filtered through a microfilter (100 μl)

[0019] Examples of the polyester polyol compound (A) used in the present invention include the following. Polyester obtained by ring-opening polymerization reaction of cyclic ester compounds such as propiolactone, butyrolactone, ε-caprolactone, σ-valerolactone, β-methyl-σ-valerolactone, etc., and aliphatic polyhydric alcohols such as glycol, glycerin, trimethylolpropane, pentaerythritol, etc. as raw materials, and polyester polyol (1) which is the reaction product thereof; Polyester polyol (2) obtained by reacting a bifunctional polyol such as glycol, dimer diol, or bisphenol, and a polyvalent carboxylic acid as raw materials; Polyester polyol (3) obtained by reacting a trifunctional or tetrafunctional aliphatic polyhydric alcohol and a polyvalent carboxylic acid as raw materials; Polyester polyol (4) obtained by reacting a bifunctional polyol, the trifunctional or tetrafunctional aliphatic polyhydric alcohol, and a polyvalent carboxylic acid as raw materials; Polyester polyol (5) which is a polymer of a hydroxyl acid such as dimethylolpropionic acid or castor oil fatty acid;

[0020] Alternatively, a polyester polyether polyurethane polyol obtained by reacting at least one of these polyester polyols (1) to (5) with a polyether polyol and an isocyanate compound; Polyester polyurethane polyol obtained by polymerizing polyester polyols (1) to (5) with an isocyanate compound to increase the molecular weight; etc. The polyester polyol compound (A) may be used alone or in combination of a plurality thereof.

[0021] Examples of the polyol used as a raw material for the polyester polyol compound (A) include glycols such as ethylene glycol, 1,2-propanediol, 1,2-butanediol, 1,2-pentanediol, 1,2-hexanediol, 1,2-heptanediol, 1,2-octanediol, 1,2-nonanediol, 1,2-decanediol, 1,3-propanediol, 2-methyl-1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, dimethylbutanediol, butylethylpropanediol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, bishydroxyethoxybenzene, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol;

[0022] trivalent or tetravalent polyhydric aliphatic alcohols such as glycerin, trimethylolethane, trimethylolpropane, pentaerythritol; bisphenols such as bisphenol A, bisphenol F, hydrogenated bisphenol A, hydrogenated bisphenol F; dimer diol; polyether polyols obtained by addition polymerization of alkylene oxides such as ethylene oxide, propylene oxide, butylene oxide, styrene oxide, epichlorohydrin, tetrahydrofuran, cyclohexylene in the presence of polymerization initiators such as the glycols, trivalent or tetravalent aliphatic polyhydric alcohols; polyether urethane polyols obtained by further increasing the molecular weight of the polyether polyol with an isocyanate compound; castor oil-based polyols such as castor oil, dehydrated castor oil, castor oil hydrogenated product castor oil, and 5 to 50 mol adducts of castor oil with alkylene oxide, and mixtures thereof, etc. can be mentioned.

[0023] Examples of the polybasic carboxylic acid used as a raw material for the polyester polyol compound (A) include aromatic polybasic acids such as phthalic acid, terephthalic acid, isophthalic acid, phthalic anhydride, 1,4-naphthalenedicarboxylic acid, 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 2,3-naphthalenedicarboxylic anhydride, naphthoic acid, trimellitic acid, trimellitic anhydride, pyromellitic acid, pyromellitic anhydride, biphenyldicarboxylic acid, 1,2-bis(phenoxy)ethane-p,p'-dicarboxylic acid, benzophenonetetracarboxylic acid, benzophenonetetracarboxylic dianhydride, 5-sodium sulfoisophthalic acid, tetrachlorophthalic anhydride, and tetrabromophthalic anhydride; methyl esterified products of aromatic polybasic acids such as dimethyl terephthalic acid and dimethyl 2,6-naphthalenedicarboxylate;

[0024] aliphatic polybasic acids such as malonic acid, succinic acid, succinic anhydride, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, fumaric acid, maleic acid, maleic anhydride, and itaconic acid; dimer acid (a liquid fatty acid mainly composed of a C36 dibasic acid produced by dimerization of a C18 unsaturated fatty acid using vegetable oil-based fats and oils and containing a monobasic acid and a tribasic acid); alkyl esterified products of aliphatic polybasic acids such as dimethyl malonate, diethyl malonate, dimethyl succinate, dimethyl glutarate, dimethyl adipate, diethyl pimelate, diethyl sebacate, dimethyl fumarate, diethyl fumarate, dimethyl maleate, and diethyl maleate;

[0025] alicyclic polybasic acids such as 1,1-cyclopentanedicarboxylic acid, 1,2-cyclopentanedicarboxylic acid, 1,3-cyclopentanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, tetrahydrophthalic anhydride, 4-methylhexahydrophthalic anhydride, hexahydrophthalic anhydride, cyclohexane-1,2,4-tricarboxylic acid-1,2-anhydride, hymic anhydride, and het acid anhydride; etc. One or more of them can be used in combination.

[0026] Among the polyol and the polyvalent carboxylic acid, the polyester polyol obtained by reacting an aliphatic polyol and an aliphatic polyvalent carboxylic acid can be preferably used because it has better biodegradability. As the aliphatic polyol, 1,2-alkanediol is particularly preferable. Examples of the 1,2-alkanediol include the aforementioned 1,2-propanediol, 1,2-butanediol, 1,2-pentanediol, 1,2-hexanediol, 1,2-heptanediol, 1,2-octanediol, 1,2-nonanediol, 1,2-decanediol, and the like.

[0027] In the present invention, among them, it is preferable to use 1,2-propanediol, diethylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,9-nonanediol, or 2-methylpropanediol, and adipic acid is preferable as the aliphatic polyvalent carboxylic acid. In particular, the combinations of diethylene glycol and adipic acid, 1,2-propanediol and adipic acid, 1,2-butanediol and adipic acid, and 1,2-pentanediol and adipic acid are particularly excellent in biodegradability. The total amount of these aliphatic polyol and aliphatic polyvalent carboxylic acid is preferably used so that the total weight is 50 to 100% by weight based on the total weight of the polyester polyol.

[0028] The hydroxyl value of the polyester polyol compound (A) is preferably in the range of 5 to 250 mgKOH / g, more preferably 5 to 100 mgKOH / g or more, and even more preferably 5 to 50 mgKOH / g or less. The hydroxyl value can be measured by the method described in JIS-K0070.

[0029] In the present invention, the polyol composition (X) may contain various polyols other than the polyester polyol compound (A). Examples of such various polyols include polymer polyols selected from polyether polyols, polyurethane polyols, polyether (polyurethane) polyols, acrylic polyols, polycarbonate polyols, polyhydroxyl alkanes, castor oil, or mixtures thereof. 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 initiators. Examples of polyether ester polyols include polyether ester polyols obtained by reacting dibasic acids such as terephthalic acid, isophthalic acid, phthalic anhydride, adipic acid, azelaic acid, sebacic acid, dimer acid, or their dialkyl esters or mixtures thereof with the above polyether polyols.

[0030] Polyurethane polyols are polyols having a urethane bond in one molecule. For example, reaction products of polyether polyols having a number average molecular weight of 200 to 20,000 and organic polyisocyanates, with an NCO / OH ratio of less than 1, preferably less than 0.9, can be mentioned. As the organic polyisocyanate, the polyisocyanate compounds described below, particularly diisocyanate compounds, can be used.

[0031] Examples of the polycarbonate polyol 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.

[0032] When the adhesive of the present invention is used as a solvent-free type, the viscosity of the polyol composition (X) is adjusted to a range suitable for the nonsolvent lamination method. As an example, the viscosity at 30 to 80°C is adjusted to be in the range of 100 to 5000 mPas, more preferably 100 to 3000 mPas. The viscosity of the polyol composition (X) can be adjusted by the skeleton of the polyester polyol compound (A) and plasticizers or the like described later. When adjusting with the skeleton of the polyester polyol compound (A), for example, the viscosity can be decreased by using polypropylene glycol or a polyester polyol obtained by reacting an aliphatic carboxylic acid and a polyol. Alternatively, the viscosity can be increased by using a polyester polyol obtained by reacting an aromatic carboxylic acid and a polyol.

[0033] When the adhesive of the present invention is used as a solvent type, the viscosity of the polyol composition (X) is adjusted to a viscosity suitable for coating by diluting with a solvent.

[0034] When the polyester polyol compound (A) used in the present invention is a reaction product of an aliphatic alcohol having a quaternary carbon atom and having a trivalent or higher hydroxyl group, examples of the aliphatic alcohol having a quaternary carbon atom and having a trivalent or higher hydroxyl group include trifunctional or tetrafunctional polyhydric alcohols such as trimethylolpropane, trimethylolethane, trimethylolbutane, and pentaerythritol.

[0035] Specific examples of the polyester polyol compound (A) which is a reaction product of an aliphatic alcohol having a quaternary carbon atom and having a trivalent or higher hydroxyl group include, for example, · A polyester polyol compound which is a reaction product of trimethylolpropane, diethylene glycol, adipic acid · A polyester polyol compound which is a reaction product of trimethylolpropane, diethylene glycol, adipic acid and isophthalic acid · A polyester polyol compound which is a reaction product of trimethylolpropane, diethylene glycol, adipic acid, isophthalic acid and trimellitic anhydride · A polyester polyol compound which is a reaction product of trimethylolpropane, diethylene glycol, adipic acid, isophthalic acid and pyromellitic anhydride · A polyester polyol compound which is a reaction product of trimethylolpropane, diethylene glycol, adipic acid, isophthalic acid and phthalic anhydride · A polyester polyol compound which is a reaction product of trimethylolpropane, diethylene glycol, adipic acid, isophthalic acid and succinic anhydride · A polyester polyol compound which is a reaction product of trimethylolpropane, 1,2-propanediol and adipic acid · A polyester polyol compound which is a reaction product of trimethylolpropane, 1,2-propanediol, adipic acid and isophthalic acid · A polyester polyol compound which is a reaction product of trimethylolpropane, 1,2-propanediol, adipic acid, isophthalic acid and trimellitic anhydride · A polyester polyol compound which is a reaction product of trimethylolpropane, 1,2-propanediol, adipic acid, isophthalic acid, and pyromellitic dianhydride · A polyester polyol compound which is a reaction product of trimethylolpropane, 1,2-propanediol, adipic acid, isophthalic acid, and phthalic anhydride · A polyester polyol compound which is a reaction product of trimethylolpropane, 1,2-propanediol, adipic acid, isophthalic acid, and succinic anhydride · A polyester polyol compound which is a reaction product of trimethylolpropane, diethylene glycol, 1,2-propanediol, and adipic acid · A polyester polyol compound which is a reaction product of trimethylolpropane, diethylene glycol, 1,2-propanediol, adipic acid, and isophthalic acid · A polyester polyol compound which is a reaction product of trimethylolpropane, diethylene glycol, 1,2-propanediol, adipic acid, isophthalic acid, and trimellitic anhydride · A polyester polyol compound which is a reaction product of trimethylolpropane, diethylene glycol, 1,2-propanediol, adipic acid, isophthalic acid, and pyromellitic dianhydride · A polyester polyol compound which is a reaction product of trimethylolpropane, diethylene glycol, 1,2-propanediol, adipic acid, isophthalic acid, and phthalic anhydride · A polyester polyol compound which is a reaction product of trimethylolpropane, diethylene glycol, 1,2-propanediol, adipic acid, isophthalic acid, and succinic anhydride Examples include the above.

[0036] Further, the polyester polyol compound (A) is preferably acid-modified and exhibits more excellent biodegradability. Specifically, the acid-modified polyester polyol compound (A) is a polyol having an acidic group in the polyol molecule. Examples of the acidic group include a carboxyl group, a phosphate group, etc. Among them, a carboxyl group is preferable in terms of ease of production. As a method for producing the acid-modified polyester polyol compound (A), there is no particular limitation, but a method of adding an acid anhydride group-containing compound to the hydroxyl group of various polyols to introduce a carboxyl group is preferably used. Examples of the acid anhydride group-containing compound to be added to various polyols include trimellitic anhydride, phthalic anhydride, hexahydrophthalic anhydride, succinic anhydride, maleic anhydride, pyromellitic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, etc. Among them, the use of trimellitic anhydride is preferred. It can also be produced by adjusting the composition so as to have both a hydroxyl group and a carboxyl group.

[0037] The acid value of the polyester polyol compound (A) is not particularly limited, but it is preferably 5 to 50 mgKOH / g, more preferably 10 to 30 mgKOH / g. If the acid value is within this range, the biodegradability is further improved. The acid value can be measured by the method described in JIS-K0070.

[0038] In addition to the polyester polyol compound (A) which is a reaction product of an aliphatic alcohol having a quaternary carbon atom and having a trivalent or higher hydroxyl group, preferred specific embodiments of the polyester polyol compound (A) include, for example, polyester polyol (A) using diethylene glycol, adipic acid, and phthalic acid as reaction raw materials, etc.

[0039] (Polyisocyanate composition (Y)) The polyisocyanate composition (Y) contains a polyisocyanate compound (B) having a plurality of isocyanate groups. The polyisocyanate compound (B) is not particularly limited, and includes aromatic diisocyanates, araliphatic diisocyanates, aliphatic diisocyanates, alicyclic diisocyanates, and burette bodies, nurate bodies, adduct bodies, allophanate bodies, carbodiimide-modified bodies, polymeric bodies, uretdione-modified bodies of these diisocyanates, urethane prepolymers obtained by reacting these polyisocyanates with polyols, etc. These can be used alone or in combination of a plurality.

[0040] Examples of aromatic diisocyanates include, but are not limited to, 2,2'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, polymethylene polyphenyl polyisocyanate (also referred to as polymeric MDI or crude MDI), 1,3-phenylene diisocyanate, 4,4'-diphenyldiisocyanate, 1,4-phenylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4'-toluidine diisocyanate, 2,4,6-triisocyanate toluene, 1,3,5-triisocyanate benzene, dianisidine diisocyanate, 4,4'-diphenyl ether diisocyanate, 4,4',4''-triphenylmethane triisocyanate, etc.

[0041] Aromatic aliphatic diisocyanate means an aliphatic isocyanate having one or more aromatic rings in the molecule, and examples include, but are not limited to, m- or p-xylylene diisocyanate (alias: XDI), α,α,α',α'-tetramethylxylylene diisocyanate (alias: TMXDI), etc.

[0042] Examples of aliphatic diisocyanates include, but are not limited to, trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate (alias: HDI), pentamethylene diisocyanate, 1,2-propylene diisocyanate, 2,3-butylene diisocyanate, 1,3-butylene diisocyanate, dodecamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, etc.

[0043] Examples of the alicyclic diisocyanate include, but are not limited to, 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate, isophorone diisocyanate (also known as IPDI), 1,3-cyclopentane diisocyanate, 1,3-cyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, methyl-2,4-cyclohexane diisocyanate, methyl-2,6-cyclohexane diisocyanate, 4,4'-methylenebis(cyclohexyl isocyanate), 1,4-bis(isocyanatomethyl)cyclohexane, etc.

[0044] As the polyol used for the synthesis of the urethane prepolymer, the same ones as those exemplified as the polyol composition (X) can be used. Since it is possible to increase the adhesive strength while reducing the viscosity of the adhesive, it is preferable to use at least one of polyalkylene glycol or polyester polyol.

[0045] As the polyalkylene glycol, those having a number average molecular weight in the range of 200 to 6,000 are preferable. The polyester polyol is preferably obtained by reacting a polyalkylene glycol with an aliphatic polycarboxylic acid having 2 to 30 carbon atoms. Further, as the raw material alcohol component of the polyester polyol, a polyhydric alcohol having 3 or more functional groups such as glycerin, trimethylolpropane, and pentaerythritol may be used in a proportion of 10% by mass or less in the polyol component.

[0046] For the soft packaging substrate, polyisocyanates obtained by reacting an aromatic polyisocyanate with a polyalkylene glycol having a number average molecular weight in the range of 200 to 6,000 and polyisocyanates obtained by reacting an aromatic polyisocyanate with a polyester polyol having a number average molecular weight in the range of 200 to 3,000 are preferable because they can impart appropriate flexibility to the cured product. Those having an isocyanate content of 5 to 20% by mass by titration method (using di-n-butylamine) are preferable because they have an appropriate resin viscosity and excellent coatability.

[0047] On the other hand, for a hard substrate, a polyisocyanate obtained by reacting an aromatic polyisocyanate with a polyester polyol having a number average molecular weight in the range of 200 to 3,000, an aromatic polyisocyanate, a polyester polyol having a number average molecular weight in the range of 200 to 3,000, and a mixture of a polyalkylene glycol having a number average molecular weight in the range of 200 to 6,000 are preferably reacted because they have excellent adhesion strength. Those having an isocyanate content of 5 to 20% by mass according to a conventional method (using di-n-butylamine) are also preferable because they have an appropriate resin viscosity and excellent coatability.

[0048] When the polyisocyanate compound (B) is a urethane prepolymer, the equivalent ratio [NCO] / [OH] of the isocyanate group to the hydroxyl group used in the reaction is preferably in the range of 1.2 to 10.0 because the viscosity of the adhesive is in an appropriate range and the coatability is good.

[0049] When the adhesive of the present invention is a solvent-free type, the viscosity of the polyisocyanate composition (Y) is adjusted to a range suitable for the non-solvent lamination method. As an example, the viscosity at 30 to 80 ° C is adjusted to be in the range of 500 to 5000 mPas, more preferably 500 to 3000 mPas. The viscosity of the polyisocyanate composition (Y) can be adjusted, for example, by the blending amount of the urethane prepolymer and the blending amount of the low molecular weight isocyanate compound.

[0050] When the adhesive of the present invention is used as a solvent type, the viscosity of the polyisocyanate composition (Y) is adjusted to a viscosity suitable for coating by diluting with a solvent.

[0051] When the polyisocyanate compound (B) used in the present invention is a reaction product of an aliphatic alcohol having a quaternary carbon atom and having a trivalent or higher hydroxyl group, examples of the aliphatic alcohol having a quaternary carbon atom and having a trivalent or higher hydroxyl group include trimethylolpropane, trimethylolethane, trimethylolbutane, pentaerythritol and the like.

[0052] Specific examples of the polyisocyanate compound (B) which is a reaction product of an aliphatic alcohol having a quaternary carbon atom and having a hydroxyl group with a valence of 3 or more include, for example, (1) A polyisocyanate compound which is a reaction product of trimethylolpropane and hexamethylene diisocyanate (2) A polyisocyanate compound which is a reaction product of trimethylolpropane and toluene diisocyanate (3) A polyisocyanate compound which is a reaction product of trimethylolpropane and isophorone diisocyanate (4) A polyisocyanate compound which is a reaction product of trimethylolpropane and xylylene diisocyanate and the like.

[0053] In the present invention, it is essential that either or both of the polyester polyol compound (A) and the polyisocyanate compound (B) are reaction products of an aliphatic alcohol having a quaternary carbon atom and having a hydroxyl group with a valence of 3 or more. Among them, it is preferable that the polyisocyanate compound (B) is a reaction product of an aliphatic alcohol having a quaternary carbon atom and having a hydroxyl group with a valence of 3 or more because better biodegradability can be obtained.

[0054] (Aromatic ring and / or aliphatic ring) In the present invention, in order for the two-component curable adhesive of the present invention to exhibit good adhesion performance, it is preferable that the polyol composition (X) and / or the polyisocyanate composition (Y), which are components of the adhesive, contain an aromatic ring and / or an aliphatic ring. As a method for introducing these aromatic rings and / or aliphatic rings into the adhesive composition, for example, a method of using the polyol or the polyvalent carboxylic acid having an aromatic ring and / or an aliphatic ring as the polyol and the polyvalent carboxylic acid which are raw materials of the polyester polyol compound (A) can be mentioned. Further, when the polyester polyol compound (A) is a polyester polyurethane polyol, a polyisocyanate having an aromatic ring and / or an aliphatic ring may be used as the polyisocyanate used in the urethanization reaction, and there is no particular limitation. Also, as the polyisocyanate compound (B), a polyisocyanate having an aromatic ring and / or an aliphatic ring can be used.

[0055] On the other hand, if the content of the aromatic ring and / or aliphatic ring becomes too high, it tends to be inferior in biodegradability and detachability when immersed in an alkaline aqueous solution. Therefore, in the present invention, the more preferable content of the aromatic ring and / or aliphatic ring is preferably 0.63 to 2.8 meq / g, and most preferably 0.65 to 2.0 meq / g, based on the total mass of the adhesive of the present invention. In the present invention, the content of the aromatic ring and / or aliphatic ring is determined by the following formula.

[0056] Content of aromatic ring and aliphatic ring in total mass of adhesive (meq / g) = (Aromatic ring (eq) + Aliphatic ring (eq)) / (Weight of polyol composition (X) (solid content) (g) + Weight of polyisocyanate composition (Y) (solid content) (g)) × 1000

[0057] (Concentration of urethane bond) In the present invention, from the viewpoints of biodegradability under compost conditions and releasability when immersed in an alkaline aqueous solution, it is preferable that the total of the urethane bond concentration and the urea bond concentration with respect to the total mass (solid content) of the adhesive of the present invention is 0.1 to 2.0 meq / g. More preferably, the total of the urethane bond concentration and the urea bond concentration is 0.2 to 1.0 meq / g. The urethane bond concentration and the urea bond concentration are values calculated by the following formulas. In the formulas, OH represents a hydroxyl group and NCO represents an isocyanate group.

[0058] Urethane bond concentration in the total mass of the adhesive (meq / g) = OH (eq) / [weight of polyol composition (X) (solid content) (g) + weight of polyisocyanate composition (Y) (solid content) (g)] × 1000

[0059] Urea bond concentration in the total mass of the adhesive (meq / g) = ([NCO (eq) - OH (eq)] / 2) / [weight of polyol composition (X) (solid content) (g) + weight of polyisocyanate composition (Y) (solid content) (g)] × 1000

[0060] OH (eq) = (polyol hydroxyl value (solid content) / 56.1) × (weight of polyol composition (X) (solid content) / 1000)

[0061] NCO (eq) = (NCO% (solid content) / 4202) × (weight of polyisocyanate composition (Y) (solid content))

[0062] (Amount of aliphatic polyhydric alcohol having a quaternary carbon atom and a trivalent or higher hydroxyl group in the total mass of the adhesive) In the present invention, when the content of an aliphatic alcohol having a quaternary carbon atom and a trivalent or higher hydroxyl group in the total mass of the adhesive increases, the biodegradability tends to increase, which is preferable. The "amount of aliphatic alcohol having a quaternary carbon atom and a trivalent or higher hydroxyl group in the total mass of the adhesive (mmol / g)" is a value calculated by the following formula, and it is preferably contained in an amount of 0.05 to 1.0 mmol / g, and most preferably 0.1 to 0.5 mmol / g, based on the total mass of the adhesive of the present invention.

[0063] Amount of aliphatic alcohol having a quaternary carbon atom and a trivalent or higher hydroxyl group in the total mass of the adhesive (mmol / g) = Amount of aliphatic alcohol having a quaternary carbon atom and a trivalent or higher hydroxyl group (mol) / [Weight of polyol composition (X) (solid content) (g) + Weight of polyisocyanate composition (Y) (solid content) (g)] × 1000

[0064] In the present invention, it is preferable to balance the content of the aromatic ring and / or aliphatic ring in the total mass of the adhesive of the present invention, the urethane bond concentration, and the amount of aliphatic alcohol having a quaternary carbon atom and a trivalent or higher hydroxyl group.

[0065] (Other components (D) of the adhesive) The adhesive of the present invention may contain components other than the above-described components. The other components (D) may be contained in either or both of the polyol composition (X) or the polyisocyanate composition (Y), or may be prepared separately and mixed with the polyol composition (X) and the polyisocyanate composition (Y) immediately before coating the adhesive for use. Hereinafter, each component will be described.

[0066] (Dehydration condensate (C) of hydroxy acid) The adhesive of the present invention can contain a compound produced by intramolecular dehydration condensation of a molecule having a hydroxy group and a carboxyl group (hydroxycarboxylic acid). Examples of the compound include lactone and lactide. Among them, the use of lactide is preferable because good biodegradability can be imparted. Examples of lactones include cyclic lactone compounds such as ε-caprolactone, γ-butyrolactone, γ-valerolactone, δ-valerolactone, and the like. Lactide is a cyclic compound having two ester bonds in a molecule formed by dehydration condensation of the hydroxy group and carboxyl group of two molecules of hydroxy acid. Specifically, for example, glycolide, 3,6-dimethyl-1,4-dioxane-2,5-dione (derived from 2-hydroxypropionic acid (lactic acid)), 1,6-dioxacyclodecane-2,7-dione (derived from 4-hydroxybutanoic acid), and the like can be mentioned. Among these, so-called lactide derived from lactic acid may be an optically active substance, and there are L-lactide, D-lactide, and meso-lactide. Among these, L-lactide and meso-lactide are preferable because they are not only easily available but also derived from plant raw materials, and thus can not only have biodegradability but also have a high biomass degree. Polyester having a lactic acid skeleton can be decomposed by an enzyme secreted from microorganisms in the soil, and thus the environmental load can be reduced.

[0067] The dehydration condensate (C) of hydroxy acid is preferably contained in an amount of 1 to 10% by mass based on the total amount of the solid content of the adhesive of the present invention, and biodegradability can be achieved within this range. More preferably, it is 2 to 5% by mass. If the addition amount of lactide is too large, it will cause a decrease in adhesive performance, which is not preferable. The dehydration condensate (C) of hydroxy acid may be contained in either one of the polyol composition (X) or the polyisocyanate composition (Y), or may be contained in both, but from the viewpoint of storage stability, it is preferably contained in the polyol composition.

[0068] (Catalyst) The adhesive of the present invention can contain a metal-based catalyst, an amine-based catalyst, an aliphatic cyclic amide compound, etc. as a catalyst.

[0069] Examples of metal catalysts include metal complex catalysts, inorganic metal catalysts, and organometallic catalysts. Examples of metal complex catalysts include acetylacetonate salts of metals selected from the group consisting of Fe (iron), Mn (manganese), Cu (copper), Zr (zirconium), Th (thorium), Ti (titanium), Al (aluminum), and Co (cobalt), such as iron acetylacetonate, manganese acetylacetonate, copper acetylacetonate, zirconia acetylacetonate, and the like.

[0070] Examples of inorganic metal catalysts include those selected from Sn, Fe, Mn, Cu, Zr, Th, Ti, Al, Co, and the like.

[0071] Examples of organometallic catalysts include organozinc compounds such as zinc octylate, zinc neodecanoate, and zinc naphthenate; organotin compounds such as stannous diacetate, stannous dioctoate, stannous dioleate, stannous dilaurate, dibutyltin diacetate, dibutyltin dilaurate, dioctyltin dilaurate, dibutyltin oxide, and dibutyltin dichloride; organonickel compounds such as nickel octylate and nickel naphthenate; organocobalt compounds such as cobalt octylate and cobalt naphthenate; organobismuth compounds such as bismuth octylate, bismuth neodecanoate, and bismuth naphthenate; titanium compounds such as tetraisopropyl titanate, dibutyltitanium dichloride, tetrabutyl titanate, butoxytitanium trichloride; titanium chelate complexes having at least one kind of aliphatic diketone, aromatic diketone, or alcohol having 2 to 10 carbon atoms as a ligand; and the like.

[0072] Examples of amine catalysts include triethylenediamine, 2-methyltriethylenediamine, quinuclidine, 2-methylquinuclidine, N,N,N’,N’-tetramethylethylenediamine, N,N,N’,N’-tetramethylpropylenediamine, N,N,N’,N”,N”-pentamethyldiethylenetriamine, N,N,N’,N”,N”-pentamethyl-(3-aminopropyl)ethylenediamine, N,N,N’,N”,N”-pentamethyldipropylenetriamine, N,N,N’,N’-tetramethylhexamethylenediamine, bis(2-dimethylaminoethyl)ether, dimethylethanolamine, dimethylisopropanolamine, dimethylaminoethoxyethanol, N,N-dimethyl-N’-(2-hydroxyethyl)ethylenediamine, N,N-dimethyl-N’-(2-hydroxyethyl)propylenediamine, bis(dimethylaminopropyl)amine, bis(dimethylaminopropyl)isopropanolamine, 3-quinuclidinol, N,N,N’,N’-tetramethylguanidine, 1,3,5-tris(N,N-dimethylaminopropyl)hexahydro-S-triazine, 1,8-diazabicyclo[5.4.0]undecene-7, N-methyl-N’-(2-dimethylaminoethyl)piperazine, N,N’-dimethylpiperazine, dimethylcyclohexylamine, N-methylmorpholine, N-ethylmorpholine, 1-methylimidazole, 1,2-dimethylimidazole, 1-isobutyl-2-methylimidazole, 1-dimethylaminopropylimidazole, N,N-dimethylhexanolamine, N-methyl-N’-(2-hydroxyethyl)piperazine, 1-(2-hydroxyethyl)imidazole, 1-(2-hydroxypropyl)imidazole, 1-(2-hydroxyethyl)-2-methylimidazole, 1-(2-hydroxypropyl)-2-methylimidazole, and the like.

[0073] Examples of aliphatic cyclic amide compounds include δ-valerolactam, ε-caprolactam, ω-enantholactam, η-capryllactam, β-propiolactam, and the like. Among these, ε-caprolactam is effective for promoting curing.

[0074] (Acid anhydride) The adhesive of the present invention can contain, as acid anhydrides, alicyclic acid anhydrides, aromatic acid anhydrides, unsaturated carboxylic acid anhydrides, etc., and one or more of them can be used in combination. More specifically, for example, phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, benzophenone tetracarboxylic anhydride, dodecenyl succinic anhydride, polyadipic anhydride, polyazelainic anhydride, polysebacic anhydride, poly(ethyl octadecanedioic acid) anhydride, poly(phenyl hexadecanedioic acid) anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, hexahydrophthalic anhydride, methyl hymic anhydride, trialkyltetrahydrophthalic anhydride, methylcyclohexenedicarboxylic anhydride, methylcyclohexenetetracarboxylic anhydride, ethylene glycol bistrimellitate dianhydride, het acid anhydride, nadic acid anhydride, methyl nadic acid anhydride, 5-(2,5-dioxotetrahydro-3-furanyl)-3-methyl-3-cyclohexane-1,2-dicarboxylic anhydride, 3,4-dicarboxy-1,2,3,4-tetrahydro-1-naphthalene succinic dianhydride, 1-methyl-dicarboxy-1,2,3,4-tetrahydro-1-naphthalene succinic dianhydride, etc. can be mentioned.

[0075] Also, those obtained by modifying the above-mentioned compounds with glycols may be used as the acid anhydrides. Examples of glycols that can be used for modification include alkylene glycols such as ethylene glycol, propylene glycol, and neopentyl glycol; polyether glycols such as polyethylene glycol, polypropylene glycol, and polytetramethylene ether glycol. Furthermore, copolymerized polyether glycols of two or more of these glycols and / or polyether glycols can also be used.

[0076] (Coupling agent) The adhesive of the present invention can contain, as coupling agents, silane coupling agents, titanate-based coupling agents, aluminum-based coupling agents, etc.

[0077] Examples of the silane coupling agent 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; and hexamethyldisilazane, γ-mercaptopropyltrimethoxysilane, and the like.

[0078] Examples of the titanate coupling agent include, for example, tetraisopropoxytitanium, tetra-n-butoxytitanium, butyl titanate dimer, tetrastearyl titanate, titanium acetylacetonate, titanium lactate, tetraoctylene glycol titanate, titanium lactate, tetrastearoxytitanium, and the like.

[0079] Examples of the aluminum coupling agent include, for example, acetoalkoxyaluminum diisopropylate and the like.

[0080] (Pigment) The adhesive of the present invention has no particular limitation on the pigment, and can contain extender pigments, white pigments, black pigments, gray pigments, red pigments, brown pigments, green pigments, blue pigments, metallic powder pigments, luminescent pigments, pearlescent pigments and other organic pigments and inorganic pigments described in the Paint Raw Material Handbook 1970 Edition (edited by the Japan Paint Industry Association), and further plastic pigments and the like.

[0081] Examples of extender pigments include precipitated barium sulfate, rice powder, precipitated calcium carbonate, calcium bicarbonate, gypsum, alumina white, silica, hydrated fine silica powder (white carbon), ultrafine anhydrous silica (aerosil), silica sand, talc, precipitated magnesium carbonate, bentonite, clay, kaolin, loess, and the like.

[0082] Specific examples of organic pigments include various insoluble azo pigments such as benzidine yellow, Hansa yellow, and Lake Red 4R; soluble azo pigments such as Lake C, Carmine 6B, and Bordeaux 10; various (copper) phthalocyanine-based pigments such as phthalocyanine blue and phthalocyanine green; various chlorine-based dye lakes such as rhodamine lake and methyl violet lake; various mordant dye-based pigments such as quinoline lake and Fast Sky Blue; various vat dye-based pigments such as anthraquinone-based pigments, thioindigo-based pigments, and perinone-based pigments; various quinacridone-based pigments such as Shin Kacya Red B; various dioxazine-based pigments such as dioxazine violet; various condensed azo pigments such as chromophthal; and aniline black, among others.

[0083] Examples of inorganic pigments include various chromates such as lead yellow, zinc chromate, and molybdate orange; various ferrocyanide compounds such as ultramarine; various metal oxides such as titanium oxide, zinc white, Mapico yellow, iron oxide, red iron oxide, chromium oxide green, and zirconium oxide; various sulfides or selenides such as cadmium yellow, cadmium red, and mercury sulfide; various sulfates such as barium sulfate and lead sulfate; various silicates such as calcium silicate and ultramarine; various carbonates such as calcium carbonate and magnesium carbonate; various phosphates such as cobalt violet and manganese violet; 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.

[0084] Examples of the plastic pigment include "Grandol PP-1000", "PP-2000S", etc. manufactured by DIC Corporation.

[0085] The pigment to be used may be appropriately selected according to the purpose. For example, since it is excellent in durability, weather resistance, and designability, it is preferable to use inorganic oxides such as titanium oxide and zinc white as the white pigment, and it is preferable to use carbon black as the black pigment.

[0086] As an example, the blending amount of the pigment is 1 to 400 parts by mass with respect to 100 parts by mass of the total solid content of the polyol composition (X) and the polyisocyanate composition (Y), and it is more preferably 10 to 300 parts by mass in order to make the adhesiveness and blocking resistance better.

[0087] (Plasticizer) The adhesive of the present invention can contain, for example, phthalate plasticizers, fatty acid plasticizers, aromatic polycarboxylic acid plasticizers, phosphoric acid plasticizers, polyol plasticizers, epoxy plasticizers, polyester plasticizers, carbonate plasticizers, etc. as the plasticizer.

[0088] Examples of the phthalate plasticizers include phthalate ester plasticizers such as dimethyl phthalate, diethyl phthalate, dibutyl phthalate, diisobutyl phthalate, dihexyl phthalate, diheptyl phthalate, di-(2-ethylhexyl) phthalate, di-n-octyl phthalate, dinonyl phthalate, diisononyl phthalate, didecyl phthalate, diisodecyl phthalate, ditridecyl phthalate, diundecyl phthalate, dilauryl phthalate, distearyl phthalate, diphenyl phthalate, dibenzyl phthalate, butyl benzyl phthalate, dicyclohexyl phthalate, octyl decyl phthalate, dimethyl isophthalate, di-(2-ethylhexyl) isophthalate, diisooctyl isophthalate, etc., and tetrahydrophthalate ester plasticizers such as di-(2-ethylhexyl) tetrahydrophthalate, di-n-octyl tetrahydrophthalate, diisodecyl tetrahydrophthalate, etc.

[0089] Examples of fatty acid plasticizers include adipic acid plasticizers such as di-n-butyl adipate, di-(2-ethylhexyl) adipate, diisodecyl adipate, diisononyl adipate, di(C6-C10 alkyl) adipate, and dibutyl diglycol adipate; azelaic acid plasticizers such as di-n-hexyl azelate, di-(2-ethylhexyl) azelate, and diisooctyl azelate; sebacic acid plasticizers such as di-n-butyl sebacate, di-(2-ethylhexyl) sebacate, and diisononyl sebacate; maleic acid plasticizers such as dimethyl maleate, diethyl maleate, di-n-butyl maleate, and di-(2-ethylhexyl) maleate; fumaric acid plasticizers such as di-n-butyl fumarate and di-(2-ethylhexyl) fumarate; itaconic acid plasticizers such as monomethyl itaconate, monobutyl itaconate, dimethyl itaconate, diethyl itaconate, dibutyl itaconate, and di-(2-ethylhexyl) itaconate; stearic acid plasticizers such as n-butyl stearate, glycerin monostearate, and diethylene glycol distearate; oleic acid plasticizers such as butyl oleate, glyceryl monooleate, and diethylene glycol monooleate; citric acid plasticizers such as triethyl citrate, tri-n-butyl citrate, acetyltriethyl citrate, acetyltributyl citrate, and acetyltri-(2-ethylhexyl) citrate; ricinoleic acid plasticizers such as methyl acetyl ricinoleate, butyl acetyl ricinoleate, glyceryl monoricinoleate, and diethylene glycol monoricinoleate; and other fatty acid plasticizers such as diethylene glycol monolaurate, diethylene glycol diperargonate, and pentaerythritol fatty acid ester.

[0090] Examples of aromatic polycarboxylic acid plasticizers include trimellitic acid plasticizers such as tri-n-hexyl trimellitate, tri-(2-ethylhexyl) trimellitate, tri-n-octyl trimellitate, triisooctyl trimellitate, triisononyl trimellitate, tridecyl trimellitate, triisodecyl trimellitate, etc.; and pyromellitic acid plasticizers such as tetra-(2-ethylhexyl) pyromellitate, tetra-n-octyl pyromellitate, etc.

[0091] Examples of phosphoric acid plasticizers include triethyl phosphate, tributyl phosphate, tri-(2-ethylhexyl) phosphate, tributoxyethyl phosphate, triphenyl phosphate, octyldiphenyl phosphate, cresyldiphenyl phosphate, cresylphenyl phosphate, tricresyl phosphate, trixylenyl phosphate, tris(chloroethyl) phosphate, tris(chloropropyl) phosphate, tris(dichloropropyl) phosphate, tris(isopropylphenyl) phosphate, etc.

[0092] Examples of polyol plasticizers include glycol plasticizers such as diethylene glycol dibenzoate, dipropylene glycol dibenzoate, triethylene glycol dibenzoate, triethylene glycol di-(2-ethylbutyrate), triethylene glycol di-(2-ethylhexoate), dibutyl methylene bisthioglycolate, etc.; and glycerin plasticizers such as glycerol monoacetate, glycerol triacetate, glycerol tributyrate, etc.

[0093] Examples of epoxy plasticizers include epoxidized soybean oil, epoxy butyl stearate, epoxy di-2-ethylhexyl hexahydrophthalate, epoxy diisodecyl hexahydrophthalate, epoxy triglyceride, epoxy octyl oleate, epoxy decyl oleate, etc.

[0094] Examples of polyester plasticizers include adipic acid-based polyesters, sebacic acid-based polyesters, phthalic acid-based polyesters, and the like.

[0095] Examples of carbonate plasticizers include propylene carbonate and ethylene carbonate.

[0096] In addition, other plasticizers include partially hydrogenated terphenyl, adhesive plasticizers, and polymerizable plasticizers such as diallyl phthalate, acrylic monomers, and oligomers. These plasticizers can be used alone or in combination of two or more.

[0097] (Form of the adhesive) The adhesive of the present invention may be in either a solvent type or a solventless type. The "solvent type" adhesive referred to in the present invention means a form used in the so-called dry lamination method, in which after the adhesive is applied to a substrate and then heated in an oven or the like to volatilize the organic solvent in the coating film, it is bonded to another substrate. Either one or both of the polyol composition (X) and the polyisocyanate composition (Y) contain an organic solvent capable of dissolving (diluting) the components of the polyol composition (X) and the components of the polyisocyanate composition (Y) used in the present invention.

[0098] Examples of organic solvents include esters such as methyl acetate, ethyl acetate, butyl acetate, dimethyl carbonate, and cellosolve acetate; ketones such as acetone, methyl ethyl ketone, isobutyl ketone, and cyclohexanone; ethers such as tetrahydrofuran and dioxane; aromatic hydrocarbons such as toluene and xylene; halogenated hydrocarbons such as methylene chloride and ethylene chloride; dimethyl sulfoxide, dimethyl sulfonamide, and the like.

[0099] In this specification, the "solventless" adhesive refers to a form of adhesive used in the so-called non-solvent lamination method, which is a method of bonding to another substrate without going through the process of heating with an oven or the like to volatilize the solvent after applying the adhesive to the substrate, without substantially containing a highly soluble organic solvent such as ethyl acetate or methyl ethyl ketone as described above for the polyol composition (X) and the polyisocyanate composition (Y). When a trace amount of organic solvent remains in the polyol composition (X) and the polyisocyanate composition (Y) because the components of the polyol composition (X) and the polyisocyanate composition (Y) and the organic solvent used as a reaction medium during the production of their raw materials cannot be completely removed, it is understood that it substantially does not contain an organic solvent. Further, when the polyol composition (X) contains a low molecular weight alcohol, since the low molecular weight alcohol reacts with the polyisocyanate composition (Y) to become a part of the coating film, there is no need to volatilize it after coating. Therefore, such a form is also treated as a solventless adhesive, and the low molecular weight alcohol is not regarded as an organic solvent.

[0100] The adhesive of the present invention is preferably used by being formulated so that the ratio [NCO] / [OH] of the number of moles [NCO] of isocyanate groups contained in the polyisocyanate composition (Y) to the number of moles [OH] of hydroxyl groups contained in the polyol composition (X) is 0.8 to 5.0, preferably 1.0 to 5.0.

[0101] (Biodegradability) The two-component curable adhesive of the present invention exhibits biodegradability. In the present invention, the biodegradability is a value determined by a method conforming to JIS K6953 1:2011. Specifically, the culture temperature is 58°C and the culture period is 28 days for evaluation. Under these conditions, the compost decomposition rate of the two-component curable adhesive of the present invention under compost conditions is more preferably 20% or more, further preferably 30% or more, and particularly preferably 40% or more.

[0102] <Laminate> The laminate of the present invention is obtained by laminating a plurality of base materials (films or papers) using the adhesive of the present invention by a dry lamination method or a non-solvent lamination method. There is no particular limitation on the film to be used, and a film suitable for the application can be appropriately selected. For example, for food packaging, polyethylene terephthalate (PET) film, polystyrene film, polyamide film, polyacrylonitrile film, polyethylene film (LLDPE: low-density polyethylene film, HDPE: high-density polyethylene film, MDOPE: uniaxially stretched polyethylene film, OPE: biaxially stretched polyethylene film), polypropylene film (CPP: unstretched polypropylene film, OPP: biaxially stretched polypropylene film), and other polyolefin films, polyvinyl alcohol film, ethylene-vinyl alcohol copolymer film, etc. can be mentioned.

[0103] Also, it is preferable to use a biomass film formed of a material containing a biomass-derived component. Biomass films are sold by various companies, and for example, sheets such as those listed in the list of biomass-certified products described by the Japan Organic Resources Association, a general incorporated foundation, can be used.

[0104] Specifically, well-known biomass films include those made from ethylene glycol derived from biomass. Ethylene glycol derived from biomass is made from ethanol (biomass ethanol) produced from biomass as a raw material. For example, biomass-derived ethylene glycol can be obtained by a method of producing ethylene glycol via ethylene oxide from biomass ethanol by a conventionally known method. Also, commercially available biomass ethylene glycol may be used, and for example, biomass ethylene glycol commercially available from Indiaglycol Co., Ltd. can be preferably used.

[0105] For example, as an alternative to polyethylene terephthalate films using conventional petroleum-based raw materials, films containing biomass polyesters such as those using ethylene glycol derived from biomass as the diol unit and dicarboxylic acids derived from fossil fuels as the dicarboxylic acid unit, biomass polyethylene terephthalate, etc. are known.

[0106] For the dicarboxylic acid unit of the biomass polyester, dicarboxylic acids derived from fossil fuels are used. As the dicarboxylic acid, aromatic dicarboxylic acids, aliphatic dicarboxylic acids, and their derivatives can be used without limitation. In addition to the above diol component and dicarboxylic acid component, a copolymer polyester may also be used in which a copolymerization component is added as a third component, such as at least one polyfunctional compound selected from the group consisting of bifunctional oxycarboxylic acids, polyhydric alcohols having three or more functional groups, polycarboxylic acids having three or more functional groups and / or their anhydrides, and oxycarboxylic acids having three or more functional groups, for forming a crosslinked structure.

[0107] Also, for example, as an alternative to polyolefin-based films using conventional petroleum-based raw materials, biomass polyolefin-based films such as biomass polyethylene-based films containing a polyethylene-based resin using ethylene glycol derived from biomass as a raw material, biomass polyethylene - polypropylene-based films, etc. are known. The polyethylene-based resin is not particularly limited except that a part of the raw material uses the ethylene glycol derived from biomass, and examples include homopolymers of ethylene, copolymers of ethylene and α-olefins with ethylene as the main component (ethylene-α-olefin copolymers containing 90 mass% or more of ethylene units), etc. These can be used alone or in combination of two or more.

[0108] The α-olefin constituting the copolymer of ethylene and α-olefin is not particularly limited, and examples thereof include α-olefins having 4 to 8 carbon atoms such as 1-butene, 4-methyl-1-pentene, 1-hexene, and 1-octene. Known polyethylene resins such as low-density polyethylene resin, medium-density polyethylene resin, and linear low-density polyethylene resin can be used. Among them, from the viewpoint of making it less likely to cause damage such as perforation or breakage even when the films rub against each other, linear low-density polyethylene resin (LLDPE) (a copolymer of ethylene and 1-hexene, or a copolymer of ethylene and 1-octene) is preferred, and the density is 0.910 to 0.925 g / cm 3 A linear low-density polyethylene resin which is is more preferred.

[0109] As for biomass films, those using biomass raw materials classified by the biomass plastic degree defined in ISO16620 or ASTM D6866 are also on the market. Radiocarbon 14C exists in the atmosphere at a ratio of 1 in 1012, and this ratio does not change even in atmospheric carbon dioxide. Therefore, this ratio does not change even in plants that have fixed this carbon dioxide by photosynthesis. For this reason, the carbon of plant-derived resins contains radiocarbon 14C. In contrast, the carbon of fossil fuel-derived resins contains almost no radiocarbon 14C. Therefore, by measuring the concentration of radiocarbon 14C in the resin with an accelerator mass spectrometer, the content ratio of plant-derived resins in the resin, that is, the biomass plastic degree, can be determined.

[0110] Examples of plant-derived low-density polyethylene, which is a biomass plastic having a biomass plastic degree of 80% or more, preferably 90% or more, as defined in ISO16620 or ASTM D6866, include "SBC818", "SPB608", "SBF0323HC", "STN7006", "SEB853", "SPB681", etc. under the trade name of Braskem. Films using these as raw materials can be preferably used.

[0111] In addition, films and sheets containing starch, which is a biomass raw material, or polylactic acid are also known. These can be appropriately selected and used according to the intended application.

[0112] The biomass film may be a laminate in which a plurality of biomass films are laminated, or a laminate of a conventional petroleum-based film and a biomass film. These biomass films may be either unstretched films or stretched films, and their manufacturing methods are not limited.

[0113] In addition, films having biodegradability are also preferable. Films and sheets containing starch, which is the aforementioned biomass raw material, or polylactic acid are known to have biodegradability. These can be appropriately selected and used according to the intended application.

[0114] The film may be subjected to a stretching treatment. As a stretching treatment method, it is common 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 general to first perform a longitudinal stretching treatment and then a transverse stretching. Specifically, a method that combines longitudinal stretching using the speed difference between rolls and transverse stretching using a tenter is often used.

[0115] If necessary, various surface treatments such as flame treatment or corona discharge treatment may be performed on the film surface so as to form an adhesive layer without defects such as film breakage or peeling.

[0116] Alternatively, a film laminated with a vapor deposition 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 such as polyvinyl alcohol, ethylene-vinyl alcohol copolymer, or vinylidene chloride may be used. By using such a film, a laminate having barrier properties against water vapor, oxygen, alcohol, inert gas, volatile organic compounds (scent), etc. can be obtained.

[0117] As the paper, a known paper base material can be used without particular limitation. Specifically, it is manufactured by a known paper-making machine using natural fibers for papermaking such as wood pulp, etc., but the papermaking conditions are not particularly defined. 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 pulp obtained by chemically modifying these pulps. As the type of pulp, chemical pulp such as kraft pulping method, acidic / neutral / alkaline sulfite pulping method, soda salt pulping method, ground pulp, chemiground pulp, thermomechanical pulp, etc. can be used. Also, various commercially available high-quality papers, coated papers, backing papers, impregnated papers, cardboard papers, and paperboards can be used.

[0118] As a more specific configuration of the laminate, (1) Substrate film 1 / Adhesive layer 1 / Sealant film (2) Substrate film 1 / Adhesive layer 1 / Unstretched metallized film (3) Substrate film 1 / Adhesive layer 1 / Stretched metallized film (4) Transparent vapor-deposited stretched film / Adhesive layer 1 / Sealant film (5) Substrate film 1 / Adhesive layer 1 / Substrate film 2 / Adhesive layer 2 / Sealant film (6) Substrate film 1 / Adhesive layer 1 / Stretched metallized film / Adhesive layer 2 / Sealant film (7) Substrate film 1 / Adhesive layer 1 / Transparent vapor-deposited stretched film / Adhesive layer 2 / Sealant film (8) Substrate film 1 / Adhesive layer 1 / Metal layer / Adhesive layer 2 / Sealant film (9) Substrate film 1 / Adhesive layer 1 / Substrate film 2 / Adhesive layer 2 / Metal layer / Adhesive layer 3 / Sealant film (10) Substrate film 1 / Adhesive layer 1 / Metal layer / Adhesive layer 2 / Substrate film 2 / Adhesive layer 3 / Sealant film etc. can be mentioned, but it is not limited thereto.

[0119] As the base material 1 used in the structure (1), there are MDOPE film, OPE film, OPP film, PET film, nylon film, various biodegradable base materials, for example, paper, cellophane film, etc. Also, as the base material 1, one with a coating applied for the purpose of improving gas barrier properties and ink receptivity when providing the printing layer described later may be used. Examples of commercially available base material films 1 with a coating applied include K-OPP film and K-PET film. The adhesive layer 1 is a cured coating film of the adhesive of the present invention. As the sealant film, there are CPP film, LLDPE film, gas barrier heat seal film, various biodegradable base materials, for example, polybutylene succinate, polylactic acid, etc. On the surface of the base material 1 on the side of the adhesive layer 1 (when using a base material film 1 with a coating applied, the surface of the coating layer on the side of the adhesive layer 1) or the surface opposite to the adhesive layer 1, a printing layer described later may be provided. The printing layer is formed by a general printing method that has been conventionally used for printing on polymer films and paper using various printing inks such as gravure ink, flexo ink, offset ink, screen ink, inkjet ink, etc.

[0120] As the base material 1 used in the structures (2) and (3), there are MDOPE film, OPE film, OPP film, PET film, paper, etc. The adhesive layer 1 is a cured coating film of the adhesive of the present invention. As the metal vapor deposition unoriented film, there are CPP film, LLDPE film, VM-CPP film obtained by vapor depositing a metal such as aluminum on a gas barrier heat seal film, VM-LLDPE film, etc. As the metal vapor deposition oriented film, VM-MDOPE film, VM-OPE film, VM-OPP film obtained by vapor depositing a metal such as aluminum on MDOPE film, OPE film, OPP film can be used. Similar to the structure (1), a printing layer may be provided on any surface of the base material 1.

[0121] Examples of the transparent vapor-deposited and stretched film used in the structure (4) include films obtained by vapor-depositing silica or alumina on an MDOPE film, an OPE film, an OPP film, a PET film, a nylon film, etc. For the purpose of protecting the inorganic vapor-deposited layer of silica or alumina, a film with a coating applied on the vapor-deposited layer may also be used. The adhesive layer 1 is a cured coating film of the adhesive of the present invention. Examples of the sealant film are the same as those in the structure (1). A printing layer may be provided on the surface of the transparent vapor-deposited and stretched film on the side of the adhesive layer 1 (in the case of using a film with a coating applied on the inorganic vapor-deposited layer, the surface of the coating layer on the side of the adhesive layer 1). The method of forming the printing layer is the same as that in the structure (1).

[0122] Examples of the base material 1 used in the structure (5) include a PET film, paper, etc. Examples of the base material 2 include a nylon film, etc. 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 are the same as those in the structure (1). Similar to the structure (1), a printing layer may be provided on any surface of the base material 1.

[0123] Examples of the base material 1 in the structure (6) are the same as those in the structures (2) and (3). Examples of the metal vapor-deposited and stretched film include VM-MDOPE film, VM-OPE film, VM-OPP film, and VM-PET film obtained by vapor-depositing a metal such as aluminum on an MDOPE film, an OPE film, 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 are the same as those in the structure (1). Similar to the structure (1), a printing layer may be provided on any surface of the base material 1.

[0124] Examples of the base material 1 in the structure (7) include a PET film, paper, etc. Examples of the transparent vapor-deposited and stretched film are the same as those 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. Examples of the sealant film are the same as those in the structure (1). Similar to the structure (1), a printing layer may be provided on any surface of the base material 1.

[0125] Examples of the base material 1 of the structure (8) include a PET film, paper, etc. Examples of the metal layer include an aluminum foil, etc. At least one of the adhesive layers 1 and 2 is a cured coating film of the adhesive of the present invention. Examples of the sealant film are the same as those of the structure (1). Similarly to the structure (1), a printing layer may be provided on either surface of the base material 1.

[0126] Examples of the base material 1 of the structures (9) and (10) include a PET film, paper, etc. Examples of the base material 2 include a nylon film, etc. Examples of the metal layer include an aluminum foil, etc. At least one layer of the adhesive layers 1, 2, and 3 is a cured coating film of the adhesive of the present invention. Examples of the sealant film are the same as those of the structure (1). Similarly to the structure (1), a printing layer may be provided on either surface of the base material 1.

[0127] The adhesive of the present invention is usually used as a two-component adhesive. Therefore, it is preferably mixed and used with the polyol composition (X) and the polyisocyanate composition (Y) immediately before use. The mixing ratio is as described above. The ratio [NCO] / [OH] of the number of moles of isocyanate groups [NCO] contained in the polyisocyanate composition (Y) to the number of moles of hydroxyl groups [OH] contained in the polyol composition (X) is preferably 0.8 to 5.0, more preferably 1.0 to 5.0.

[0128] When the adhesive of the present invention is a solvent type, the adhesive of the present invention is applied to the film material serving as the base material using a roll such as a gravure roll, and after volatilizing the organic solvent by heating in an oven or the like, the other base material is laminated to obtain the laminate of the present invention. It is preferable to perform an aging treatment after lamination. The aging temperature is preferably from room temperature to 80°C, and the aging time is preferably from 12 to 240 hours.

[0129] When the adhesive of the present invention is a solventless type, the adhesive of the present invention preliminarily heated to about 40°C to 100°C is applied to the film material serving as the base material using a roll such as a gravure roll, and then the other base material is immediately laminated to obtain the laminate of the present invention. It is preferable to perform an aging treatment after lamination. The aging temperature is preferably room temperature to 70°C, and the aging time is preferably 6 to 240 hours.

[0130] The coating amount of the adhesive is adjusted as appropriate. In the case of a solvent-based adhesive, as an example, the solid content is 1 g / m 2 or more and 10 g / m 2 or less, preferably 2 g / m 2 or more and 5 g / m 2 or less. In the case of a solventless adhesive, the coating amount of the adhesive is, as an example, 1 g / m 2 or more and 5 g / m 2 or less, preferably 1 g / m 2 or more and 3 g / m 2 or less.

[0131] (Printing layer) The printing layer is a layer on which characters, figures, symbols, and other desired patterns are printed. The printing method and printing ink are not particularly limited, and known printing methods and printing inks can be used. Gravure printing inks, flexographic printing inks (in the industry, gravure printing inks and flexographic printing inks are sometimes referred to as liquid printing inks), ultraviolet curable inks for lithographic offset printing, electron beam curable inks for lithographic offset printing, ultraviolet curable inks for inkjet recording printing, electron beam curable inks for inkjet recording printing, etc. are often used for the film used as the above-mentioned base material. In addition, printing inks combined with these printing methods and methods of curing with active energy rays such as ultraviolet rays (UV), LEDs, and electron beams (EB), or methods of curing with heat are also used. Also, depending on the solvent used, there may be a way of saying aqueous ink or organic solvent-based ink.

[0132] Specifically, gravure printing inks, flexographic printing inks (in the industry, gravure printing inks and flexographic printing inks are sometimes referred to as liquid printing inks), ultraviolet curable inks for lithographic offset printing, electron beam curable inks for lithographic offset printing, ultraviolet curable inks for inkjet recording printing, electron beam curable inks for inkjet recording printing, etc. can be mentioned.

[0133] In addition to the above-described configurations (1) to (10), the laminate of the present invention may further include other films or base materials. As other base materials, in addition to the above-described stretched film, unstretched film, and transparent vapor-deposited film, porous base materials such as paper, wood, and leather described later can also be used. The adhesive used when bonding other base materials may or may not be the adhesive of the present invention.

[0134] The "other layer" may contain known additives and stabilizers, such as antistatic agents, easy-adhesion coating agents, plasticizers, lubricants, antioxidants, and the like. Further, the "other layer" may be one in which the surface of the film is subjected to corona treatment, plasma treatment, ozone treatment, chemical treatment, solvent treatment, etc. as a pretreatment in order to improve the adhesion when laminated with other materials.

[0135] <Packaging material> The packaging material of the present invention is formed into a bag shape by molding the above-described laminate and heat-sealing it to form a packaging material. Examples of the form of the packaging material include various types such as three-side seal bags, four-side seal bags, gusset packaging bags, pillow packaging bags, bottomed containers of the gable top type, Tetra Classic, Bruck type, tube containers, paper cups, and lid materials. Further, an easy-opening treatment or resealing means may be appropriately provided on the packaging material of the present invention.

[0136] The packaging material of the present invention can be industrially used mainly as a packaging material for filling foods, detergents, and pharmaceuticals. As the contents to be filled, for example, as foods, confectioneries such as rice confectioneries, bean confectioneries, nuts, biscuits / cookies, wafers, marshmallows, pies, semi-cooked cakes, candies, snack foods, staples such as bread, snack noodles, instant noodles, dried noodles, pasta, aseptic packed rice, congee, oatmeal, mochi, cereal foods, pickles, boiled beans, natto, miso, frozen tofu, tofu, shiitake mushrooms, konjac, processed wild vegetables, jams, peanut creams, salads, frozen vegetables, processed agricultural products such as processed potatoes, processed livestock products such as hams, bacon, sausages, processed chicken, and corned beef, processed fishery products such as fish ham / sausage, fishery processed products, kamaboko, nori, tsukudani, bonito flakes, salted fish, smoked salmon, spicy cod roe, fruits such as peaches, oranges, pineapples, apples, pears, and strawberries, vegetables such as corn, asparagus, mushrooms, onions, carrots, daikon radishes, and potatoes, frozen prepared foods represented by hamburgers, meatballs, fried fish, gyoza, and croquettes, cooked foods such as chilled prepared foods, dairy products such as butter, margarine, cheese, cream, instant creamy powder, and formula milk for baby care, liquid seasonings, retort curries, pet foods, etc. can be mentioned.

[0137] Also, as non-foods, it can be used as various packaging materials such as tobacco, disposable hand warmers, pharmaceuticals such as infusion packs, liquid laundry detergents, kitchen liquid detergents, bath liquid detergents, bath liquid soaps, liquid shampoos, liquid conditioners, cosmetics such as lotions and milky lotions, vacuum insulation materials, and batteries.

[0138] <Method for Separating and Recycling Laminated Body> The laminated body of the present invention and the packaging material using the laminated body can be separated and recovered into each base material by a treatment using an alkaline solution, which is the most common recycling treatment at present. For example, it can be separated and recovered by a recycling method having a step of separating the laminated body into each layer by immersing the laminated body in a peeling liquid such as an alkaline solution while heating and stirring the laminated body at 20 to 90 °C, and a step of recovering each separated layer.

[0139] The alkali solution used in the separation and recovery method is preferably an aqueous solution of sodium hydroxide, an aqueous solution of potassium hydroxide, or the like. The aqueous solution of sodium hydroxide or the aqueous solution of potassium hydroxide is preferably an aqueous solution having a concentration of 0.5% by mass to 10% by mass, more preferably an aqueous solution having a concentration of 1% by mass to 5% by mass. The pH is preferably 10 or more.

[0140] The alkali solution may 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, acetonylacetone, acetylacetone, ethylene glycol monomethyl ether acetate (methyl cellosolve acetate), diethylene glycol monomethyl ether acetate (methyl carbitol acetate), diethylene glycol monoethyl ether acetate (carbitol acetate), ethyl hydroxyisobutyrate, and ethyl lactate. These can be used alone or in combination of two or more.

[0141] The content of the water-soluble organic solvent in the alkali solution is preferably 30% by mass to 70% by mass, more preferably 40% by mass to 60% by mass.

[0142] The alkaline solution may contain a water-insoluble organic solvent. 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; ether solvents such as ethyl ether and butyl ether. These can be used alone or in combination of two or more.

[0143] The alkaline solution may contain a surfactant. Examples of the surfactant include various anionic surfactants, nonionic surfactants, cationic surfactants, and amphoteric surfactants. Among these, anionic surfactants and nonionic surfactants are preferred.

[0144] Examples of the anionic surfactant include alkylbenzene sulfonates, alkylphenyl sulfonates, alkylnaphthalene sulfonates, higher fatty acid salts, sulfate esters of higher fatty acid esters, sulfonates of higher fatty acid esters, sulfate esters 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 thereof include dodecylbenzene sulfonate, isopropylnaphthalene sulfonate, monobutylphenylphenol monosulfonate, monobutylbiphenyl sulfonate, and dibutylphenylphenol disulfonate.

[0145] Examples of nonionic surfactants include polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenyl 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 alkyl amines, polyoxyethylene fatty acid amides, fatty acid alkanolamides, alkyl alkanolamides, acetylene glycols, oxyethylene adducts of acetylene glycols, polyethylene glycol polypropylene glycol block copolymers, etc. Among these, polyoxyethylene nonyl phenyl ether, polyoxyethylene octyl phenyl ether, polyoxyethylene dodecyl phenyl ether, polyoxyethylene alkyl ether, polyoxyethylene fatty acid ester, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, fatty acid alkanolamide, acetylene glycol, oxyethylene adduct of acetylene glycol, polyethylene glycol polypropylene glycol block copolymer are preferred.

[0146] As other surfactants, silicone surfactants such as polyoxyethylene adducts of polysiloxanes; fluorine surfactants such as perfluoroalkyl carboxylates, perfluoroalkyl sulfonates, oxyethylene perfluoroalkyl ethers; biosurfactants such as spiculisporic acid, rhamnolipid, lysophosphatidylcholine, etc. can also be used.

[0147] These surfactants can be used alone or in combination of two or more. When adding a surfactant, the addition amount is preferably in the range of 0.001 to 2% by mass, more preferably 0.001 to 1.5% by mass, and even more preferably in the range of 0.01 to 1% by mass based on the total amount of the alkaline solution.

[0148] The alkaline solution preferably contains terpene compounds. Examples of terpene compounds include monoterpenes such as α-pinene, β-pinene, limonene, β-farnesene, α-terpinene, γ-terpinene, ocimene, myrcene, camphene, terpinolene, sylvestrene, sabinene, caryophyllene, tricyclene, and fenchene; sesquiterpenes such as longifolene, caryophyllene, bisabolene, santalene, gingerene, curcumene, cadinene, sesquiborneol, and cedrene; diterpenes such as cembrene, podocarpene, miltirene, phyllocladene, and totarene; etc. Terpene hydrocarbons,

[0149] monoterpene alcohols such as β-citronellol, geraniol, nerol, linalool, terpineol, carpeol, twinol, pinocamphoneol, and fenchyl alcohol; sesquiterpene alcohols such as farnesol, nerolidol, cadinol, eudesmol, guaiol, bachulalcohol, carotol, lanceol, and kesso glycol; diterpene alcohols such as phytol, sclareol, manool, hinokitiol, feruginol, and totarol; etc. Terpene alcohols,

[0150] terpene aldehydes such as citronellal, citral, cyclocitral, safranal, farnal, and perillyl aldehyde,

[0151] monoterpene ketones such as dagetone, ionone, iron, carvomentone, carbotanacetone, piperitenone, tuyon, and carone; sesquiterpene ketones such as cyperone, elemol, and zerumbone; diterpene ketones such as sugiol and ketomanoyl oxide; etc. Terpene ketones.

[0152] These can be used alone or in combination of two or more. It is preferable to use terpene hydrocarbons, and more preferably to use limonene.

[0153] The content of the terpene compound can be adjusted as appropriate. As an example, it is preferably 0.1% by mass or more and 90% by mass or less of the alkaline solution, more preferably 1% by mass or more, and still more preferably 5% by mass or more. Also, the content of the terpene compound is more preferably 50% by mass or less of the alkaline solution.

[0154] In the treatment tank, the laminate is immersed in an alkaline solution heated to 20 to 90°C. The heating method is not particularly limited, and known heating methods such as by heat rays, infrared rays, microwaves, etc. can be adopted. Vibration by ultrasonic waves may be applied during immersion. For example, a method of attaching an ultrasonic vibrator to the treatment tank and applying ultrasonic vibration to the alkaline solution can be adopted.

[0155] When the laminate is immersed, it is preferable that the alkaline solution is stirred. Examples of the stirring method include a method of mechanically stirring the dispersion of the laminate accommodated in the treatment tank with a stirring blade, a method of stirring the water flow with a water flow pump, a bubbling method with an inert gas such as nitrogen gas, etc., and these methods may be used in combination to efficiently peel the laminate.

[0156] The time for immersing the laminate in the alkaline solution generally ranges from 2 minutes to 48 hours, although it depends on the composition of the laminate. If the immersion time is less than 2 minutes, there is a risk that the adhesive layer may not be completely peeled from the laminate and a part may remain. The number of times of immersion in the alkaline solution may be once or divided into several times.

[0157] In most cases, the laminate is provided with a printing ink layer for displaying a product name or the like and imparting decorativeness in addition to the adhesive. However, by immersing the laminate in the alkaline solution, the printing ink layer can also be peeled or dissolved. Also, the laminate may have a metal foil or vapor deposition film such as aluminum laminated thereon, and in the present invention, the metal foil or vapor deposition film can also be peeled or dissolved.

[0158] The alkaline solution used in the separation and recovery method is presumed to cause interfacial peeling between the laminate and the adhesive or printing ink by acting on the interface between the laminate and the adhesive or printing ink and significantly reducing the adhesive force. Although the cured coating film of a normal reaction-type adhesive or the like hardly dissolves in any solution, in the present invention, dissolution is not achieved, but interfacial peeling is caused, so it is presumed that separation and recovery can be efficiently performed in a short time.

[0159] (Recycled plastic) Each base material obtained by separating and recovering the laminate or package using the two-component curable adhesive of the present invention by the above separation and recovery method can be processed by various known recycled plastic processing methods to produce recycled plastic. Alternatively, when there are no special requirements for the hue and the like of the obtained recycled plastic, the laminate or package using the two-component curable adhesive of the present invention can be directly processed by various known recycled plastic processing methods to produce recycled plastic.

[0160] As an example of a specific embodiment, a method for producing recycled plastic can be obtained by a production method having a step of separating the laminate of the present invention into each base material, or a step of crushing the laminate or package of the present invention, a step of melt-kneading the crushed film pieces, and a step of pelletizing the melt-kneaded kneaded product.

[0161] The crusher used during crushing (pulverization) may be a known crusher and is not particularly limited. The crushed film pieces are physically blended by melt-kneading, solvent-cast blending, latex blending, polymer complexing, etc. In particular, the melt-kneading method is common. Examples of the apparatus for kneading include a tumbler, Henschel mixer, rotary mixer, super mixer, ribbon tumbler, V blender, etc. After melt-kneading with such a kneading apparatus, it is pelletized. For melt-kneading pelletization, a single-screw or multi-screw extruder is generally used, and it may be fed as it is in the form of film pieces, or after being subjected to heat or non-heat compression volume reduction treatment. Further, in addition to these extruders, a Banbury mixer, roller, co-kneader, blast mill, Brabender plastograph, etc. can also be used, and these are operated batchwise or continuously. Also, instead of melt-kneading, a method of using it as a molding resin and performing melt-kneading in the heating cylinder of a molding machine may be used.

Example

[0162] Hereinafter, the present invention will be described in more detail with specific synthesis examples and examples, but the present invention is not limited to these examples. In the following examples, "parts" and "%" represent "parts by mass" and "mass %", respectively, unless otherwise specified.

[0163] <Synthesis of polyol> (Synthesis Example 1) Into a polyester reaction vessel equipped with a stirrer, nitrogen gas introduction tube, rectification tube, and water separator, 41.8 parts of diethylene glycol (DEG), 43.2 parts of adipic acid (AA), 15 parts of isophthalic acid (IPA), and 50 ppm of titanium tetraisopropoxide (TIPT) were charged, and it was gradually heated under a nitrogen stream so that the temperature at the upper part of the rectification tube did not exceed 100 °C, and the internal temperature was maintained at 230 °C. After the acid value fell below the specified value, the reaction was continued for another 1 hour. The pressure was reduced to 30 mmHg, and when it reached 2 mgKOH / g or less, the reaction was terminated to obtain polyester polyol A-1.

[0164] (Synthesis Example 2) After obtaining a polyester polyol in the same manner as in Synthesis Example 1, 2 parts of trimellitic anhydride were added at 190 °C to obtain A-5.

[0165] (Synthesis Examples 3 to 11) Except for changing the compounding amounts as shown in Table 1, polyester polyols A-2 to A-4, A-6 to A-11 were obtained in the same manner as in Synthesis Example 1 or Synthesis Example 2. Table 1 shows the raw materials and physical property values of the polyols. The blank spaces represent non-blending.

[0166]

Table 1

[0167] (Preparation of Adhesive) The polyol composition (X) and the polyisocyanate composition (Y) were mixed in the compounding ratios shown in Table 2 to prepare the adhesives of Examples 1 to 10 and Comparative Examples 1 to 3.

[0168] (Compost Biodegradability Evaluation) (Method 1) A two-component curable adhesive (solid content: 3 g / m 2 ) formulated in combinations of Examples or Comparative Examples was coated on a polyethylene terephthalate film and aged at 50 °C for 72 hours to obtain a coating film for biodegradability evaluation. Since the adhesive alone had high adhesiveness and could not maintain the coating film shape, it was evaluated as a thin film on the polyethylene terephthalate film. The compost degradability was measured by a method conforming to JIS K6953-1:2011. *Cultivation temperature: 58 °C, Cultivation period: 28 days *Evaluation criteria: A: Compost decomposition rate of 40% or more B: Compost decomposition rate of 30% or more and less than 40% C: Compost decomposition rate of 20% or more and less than 30% D: Compost decomposition rate of 10% or more and less than 20% (practical lower limit) E: Compost decomposition rate of less than 10%

[0169] (Method 2) In Method 1 for evaluating the compost biodegradability, the compost biodegradability of the adhesives of Examples 3 and 5 to 10 was measured in the same manner as Method 1, except that the polyethylene terephthalate film was replaced with single-sided kraft paper (manufactured by Nippon Paper Industries Co., Ltd., Capital Wrap).

[0170] (Method 3) In Method 1 for evaluating the compost biodegradability, the compost biodegradability of the adhesives of Example 1, Examples 3 and 5 to 10 was measured in the same manner as Method 1, except that the polyethylene terephthalate film was replaced with a biodegradable sealant film: polybutylene succinate film (manufactured by Mitsubishi Chemical Corporation, BioPBS TM FD92).

[0171] <Delamination evaluation> A biaxially oriented polypropylene film (manufactured by Toyobo Co., Ltd., P2161 OPP film) and an unoriented polypropylene film (manufactured by Toyobo Co., Ltd., P1128 CPP film) were coated with a two-component curable adhesive (solid content: 3 g / m 2 ) prepared by combining them in the combinations of Examples or Comparative Examples, and laminated to obtain a laminate. The laminate obtained above was cut into pieces of 20 mm × 20 mm to obtain test pieces. The test pieces were immersed in a release agent heated to 70°C and stirred at 400 rpm. After immersion, the test pieces were taken out, washed and dried with ion-exchanged water, and the peeling area (%) of the adhesive was examined by color development with neocarmin. When it was completely peeled, it was 100%. The immersion time was 3 hours. As the release liquid, a solution prepared by dissolving 2 parts of sodium hydroxide in a mixed solution of 48 parts of water and 50 parts of ethanol was used. A (optimal): peeling area is 100% B (excellent): peeling area is less than 90 - 100% C (good): peeling area is less than 80 - 90% D (acceptable): peeling area is less than 70 - 79% E (unacceptable): peeling area is less than 70%

[0172] <Adhesive strength evaluation> (Method 1) Cellophane film (manufactured by Futamura Chemical Co., Ltd.; NATUREFLEX NP 23μm) and PBS film (manufactured by Mitsubishi Chemical Corporation; BioPBS film 30μm) as a sealant film were compounded in a combination of examples or comparative examples with a two-component curable adhesive (solid content: 3 g / m 2 ), laminated at 50°C for 72 hours to obtain a laminate. At an ambient temperature of 25°C, using a tensile testing machine manufactured by Shimadzu Corporation, the peeling speed was set to 300 mm / min, and the peak of the tensile strength when both ends of the adhesive strength measurement sample were pulled was defined as the adhesive strength. The unit of the adhesive strength is N / 15 mm. *Evaluation criteria: A (best): Adhesive strength is 2.0 N or more B (good): Adhesive strength is 1.5 N or more and less than 2.0 N C (fair): Adhesive strength is 1.0 N or more and less than 1.5 N D (passable): Adhesive strength is 0.5 N or more and less than 1.0 N (practical lower limit) E (unacceptable): Adhesive strength is less than 0.5 N (not suitable for practical use)

[0173] (Method 2) In Method 1 for evaluating the adhesive strength, the cellophane film was replaced with single-sided bleached kraft paper (manufactured by Nippon Paper Industries Co., Ltd., Capital Wrap), and the adhesive strength of the laminate was measured in the same manner as Method 1 except that the coating amount of the two-component curable adhesive was (solid content: 5 g / m 2 ).

[0174] The results are shown in Table 2. The blank spaces represent non-formulation.

[0175]

Table 2

[0176] In Table 2, the abbreviations are as follows. HDI-TMP: Sumidule HT manufactured by Covestro (adduct of hexamethylene diisocyanate (HDI) and trimethylolpropane (TMP). Trimethylolpropane is an aliphatic alcohol having a quaternary carbon atom and a hydroxyl group with a valence of 3 or more) TDI-TMP: Desmodul L-75 manufactured by Covestro (adduct of toluene diisocyanate (TDI) and trimethylolpropane (TMP). Trimethylolpropane is an aliphatic alcohol having a quaternary carbon atom and a hydroxyl group with a valence of 3 or more HDI-nurate: Sumidule N3300 manufactured by Covestro (nurate of hexamethylene diisocyanate (HDI)) HDI-Biuret: Duranate 24A-100 manufactured by Asahi Kasei (biuret of hexamethylene diisocyanate (HDI))

[0177] As a result, the two-component curable adhesives of Examples 1 to 10 exhibited excellent compost biodegradability and delamination properties while maintaining a practically sufficient adhesive strength. On the other hand, Comparative Examples 1 to 3 were examples where neither the polyester polyol compound (A) nor the polyisocyanate compound (B) was a reaction product of an aliphatic alcohol having a quaternary carbon atom and a hydroxyl group with a valence of 3 or more, and they were inferior in compost biodegradability and delamination properties.

Claims

1. A biodegradable two-component curable adhesive comprising a polyol composition (X) containing a polyester polyol compound (A) and a polyisocyanate composition (Y) containing a polyisocyanate compound (B), wherein the number average molecular weight of the polyester polyol compound (A) ranges from 500 to 20,000, the polyester polyol compound (A) is a reaction product obtained by using an aliphatic polyol, an aliphatic alcohol having a quaternary carbon atom and a hydroxyl group of trivalent or higher, a polyvalent carboxylic acid, and an acid anhydride group-containing compound as part of the raw materials, the acid value of the polyester polyol compound (A) is 5 to 50 mgKOH / g, the polyisocyanate compound (B) is a nurate body and / or an adduct body of a diisocyanate, a biodegradable two-component curable adhesive, characterized in that the content of an aromatic ring and / or an aliphatic ring in the total mass of the two-component curable adhesive is 0.63 to 2.8 meq / g.

2. The biodegradable two-component curable adhesive according to claim 1, wherein the aliphatic polyol in the polyester polyol compound (A) is diethylene glycol, 1,2-propanediol, 1,2-butanediol, 1,2-pentanediol, 1,2-hexanediol, 1,2-heptanediol, 1,2-octanediol, 1,2-nonanediol, and / or 1,2-decanediol, and the polyvalent carboxylic acid is an aliphatic polyvalent carboxylic acid and / or an aromatic polybasic acid.

3. The biodegradable two-component curable adhesive according to claim 1, wherein the polyisocyanate compound (B) is a nurate body and / or an adduct body of an aromatic diisocyanate and / or an aliphatic diisocyanate.

4. The biodegradable two-component curable adhesive according to claim 1, wherein the polyisocyanate compound (B) is a nurate body and / or an adduct body of hexamethylene diisocyanate and / or tolylene diisocyanate.

5. The biodegradable two-component curable adhesive according to claim 1, wherein the amount of the aliphatic alcohol having a quaternary carbon atom and a hydroxyl group of trivalent or higher in the total mass of the two-component curable adhesive is 0.05 to 1.0 mmol / g.

6. The biodegradable two-component curable adhesive according to claim 1, which contains a dehydration condensate (C) of a hydroxycarboxylic acid.

7. A laminate comprising a first substrate, a second substrate, and an adhesive layer disposed between the first substrate and the second substrate, wherein the adhesive layer is a cured coating film of the biodegradable two-component curable adhesive according to any one of claims 1 to 6.

8. A packaging material using the laminate according to claim 7.

9. A method for recycling a laminate, comprising a step of immersing a laminate including a first substrate, a second substrate, and an adhesive layer disposed between the first substrate and the second substrate, wherein the adhesive layer is a cured coating film of the biodegradable two-component curable adhesive according to any one of claims 1 to 6, in a stripping liquid to separate the laminate into each layer, and a step of recovering each separated layer.

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