Material recycling method

Abstract

To provide a recycling method for separating and recovering a material part (a1) from a treating object (a) which is a composite material composed of at least one or more chemical parts (a2) and at least one or more material parts (a2).SOLUTION: By adjusting the molar ratio X / Y to 0.002 or more and the molar ratio Z / Y to 0.3 or more and 30 or less in the treatment liquid containing the catalyst (b), the nucleophilic agent (c), and the solvent (d) (where X+Y+Z=100 when the respective molar fractions are Xmol%, Ymol%, and Zmol%), the urethane bond contained in the treatment target (a) can be decomposed at a temperature lower than that in the related art, particularly at a temperature of lower than 100°C, and the material part (a2) remaining without being decomposed can be separated and recovered.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for recycling materials to be treated.

[0002] In the present invention, the "processing target" refers to a target having at least one or more chemical parts and at least one or more material parts. In addition, a series of operations in the present invention is abbreviated as "processing." Here, the "chemical part" refers to a component bound via a specific chemical bond. That is, in the present invention, it refers to a component that can be decomposed under conditions in which a specific catalyst, nucleophile, and solvent are appropriately combined and at a temperature of less than 100°C (hereinafter, such reaction conditions may be abbreviated as "the reaction conditions of the present invention"). The "material part" refers to a component that is not bound via a specific chemical bond, i.e., a component that remains undecomposed under the reaction conditions of the present invention.

[0003] In the present invention, the term "decomposition" refers to a process of causing a nucleophilic substitution reaction at the specific chemical bond to separate the compound into components derived from two or more constituent elements. Hereinafter, such a chemical reaction will be abbreviated as a "decomposition reaction." Therefore, in the present invention, "decomposition" does not include a case in which only the chemical part contained in the target to be treated is simply dissolved in a solvent without being separated into components derived from two or more constituent elements. In the reaction conditions of the present invention, the specific chemical bond that undergoes the nucleophilic substitution reaction is at least one selected from a urethane bond, an ester bond, and a carbonate bond. On the other hand, nucleophilic substitution reaction does not occur in a urea bond or an amide bond. Therefore, for example, when a urethane bond and an amide bond coexist in the treatment target, the urethane bond can be selectively decomposed, while the amide bond remains undecomposed, allowing material recycling of the material part having the amide bond.

[0004] More specifically, the present invention relates to a recycling method involving separation and recovery of the material part from the object to be treated. Here, the processing target in the present invention is composed of at least two or more components, namely, the chemical part and the material part, and therefore takes the form of a complex. The term "complex" refers to a physical combination of two or more different components. In other words, it refers to a complex in which the chemical part and the material part are not bonded via a chemical bond. Taking the structure of a typical PET bottle as an example, a composite in which two or more different components are physically combined would be the bottle body and cap, or the bottle body and label, which are not combined via chemical bonds. On the other hand, a bottle body made of polyethylene terephthalate that has been partially chemically modified corresponds to a composite in which two or more different components are chemically combined. Such a composite in which the chemical part and the material part are chemically bonded is not included in the composite of the present invention.

[0005] In the present invention, "separation and recovery" does not simply refer to a physical operation, but also includes an operation of recovering the material part, i.e., the component of the complex that remains undecomposed, by a decomposition reaction under the reaction conditions of the present invention.

[0006] Completely decomposing the chemical parts in the complex into the smallest monomer units and purifying the decomposition products to remove impurities not only requires a lot of energy but is also time-consuming. Therefore, "recycling" in this invention refers to treating the composite to a state where it can be reused as a resource. In other words, the purpose is to reduce the energy consumption and labor required for recycling. It is sufficient to decompose the composite to an extent that the material parts can be separated and recovered, and the main focus is on reusing the material parts as resources (material recycling). Hereinafter, decomposition intended for material recycling will be abbreviated as "material recycling decomposition." As long as the material parts can be separated and recovered from the composite, it is not necessary for all of the chemical parts to be decomposed. Material recycling also includes separation and recovery of the chemical parts from the composite due to partial decomposition of the chemical parts, which weakens their interaction with the material parts. On the other hand, in the present invention, it is not essential to decompose the chemical parts by chemically treating the composite and reuse the components resulting from the chemical parts and the components resulting from the catalyst as resources (chemical recycling). However, chemical recycling that aims to reduce energy consumption and shorten the process is not excluded. Hereinafter, among decompositions, decompositions intended for chemical recycling will be abbreviated as "chemical recycling decomposition" to distinguish it from the material recycling decomposition. The solvent used in the present invention can be recovered and reused by distillation or the like. [Background technology]

[0007] Plastics are inexpensive and highly durable materials. Due to their convenience, polyethylene terephthalate (PET) in particular has been widely used in a wide range of applications, including fibers, films, and bottles, and its production and consumption have rapidly increased over the past few decades. However, despite its durability, PET is not easily biodegradable, leading to the filling of landfills around the world and the resulting marine pollution caused by microplastics, which is a major social issue in terms of environmental destruction. Given this background, there is a need for the development of recycling technologies for PET and other plastic waste. Compared to Europe and the United States, Japan has a higher proportion of thermal recycling, which utilizes the heat energy generated during incineration, but there are concerns about global warming due to carbon dioxide emissions. As a result, much research has been conducted into chemical recycling of polyester products, i.e., methods of chemically converting polyester products into monomers, recovering them, and reusing these monomers.

[0008] Patent Document 1 discloses a method for continuously producing aromatic dimethyl dicarboxylic acid and dihydric alcohol, which are monomer components of aromatic polyester such as PET, from the aromatic polyester using supercritical alcohol, but requires high temperatures of 300°C or higher.

[0009] Patent Document 2 discloses a method for producing dimethyl terephthalate by depolymerizing polyester with alkylene glycol and then transesterifying it with methanol. The method is characterized by the use of a specific calcium-containing catalyst, which allows the second-stage transesterification reaction to be carried out at temperatures between 35°C and 90°C. The first-stage depolymerization reaction is carried out in excess alkylene glycol heated to 120-230°C. Furthermore, in order to reduce the amount of methanol used in the second-stage transesterification reaction, it is preferable to concentrate the depolymerized liquid obtained after the depolymerization reaction by distilling and evaporating a portion of the alkylene glycol from the depolymerized liquid. Furthermore, it has been shown that the purity of dimethyl terephthalate can be increased by separating the resulting dimethyl terephthalate crystals into solids and liquids using solid-liquid separation means such as centrifugation, or by purifying the resulting crude dimethyl terephthalate by distillation when a highly pure product is desired. Therefore, the recycling process involves a large number of steps, consuming a lot of energy. Considering the effective use of limited resources, a method with many steps is not desirable, and it is also desirable to reduce energy consumption.

[0010] In contrast to these prior art documents, research has already been conducted into methods for decomposing polyesters at temperatures below 100°C. Patent Document 3 discloses a process for converting polyethylene terephthalate or poly(ethylene glycol-co-1,4-cyclohexanedimethanol terephthalate) into terephthalic acid esters by depolymerization. The process includes contacting the polyester with a solvent for swelling, an alcoholic solvent, and a substoichiometric amount of alkoxide. In particular, the examples use dichloromethane or dimethyl sulfoxide as the solvent for swelling the polyester, methanol as the alcoholic solvent, and a substoichiometric amount of sodium methoxide as the alkoxide, and demonstrate that polyethylene terephthalate is converted to dimethyl terephthalate at 50 to 60°C.

[0011] Research is also underway into methods for decomposing polycarbonate resins with high reactivity, even under mild conditions with little environmental impact. Patent Document 4 discloses a method for producing bisphenols by decomposing a polycarbonate resin in the presence of an alkyl ester, an aliphatic alcohol, and a catalyst. In particular, it is disclosed that the aliphatic alcohol is any one selected from the group consisting of methanol, ethanol, butanol, and ethylene glycol. It also discloses that the catalyst is any one selected from the group consisting of alkali metal hydroxides, alkali metal alkoxides, alkali metal carbonates, alkali metal oxides, alkylamines, and pyridines. It also discloses that the decomposition temperature is 150°C or lower.

[0012] Meanwhile, although research is also being conducted into the decomposition of polyurethane materials, the majority of the decomposition occurs under high temperature conditions of 100°C or higher. Patent Document 5 discloses a method for decomposing waste urethane resin, filled with a uniformly dispersed reinforcing material, into monomers using a decomposing agent whose main component is alcohol. In particular, the method for decomposing reinforcing-material-filled urethane resin involves carrying out decomposition treatment at a temperature of 240 to 350°C for 1 to 30 minutes using 5 to 20 parts by weight of the decomposing agent per 100 parts by weight of the waste urethane resin.

[0013] In recent years, methods for decomposing polyurethane materials under milder conditions have also been reported. Patent Document 6 discloses a method for decomposing polymer compounds having a specific conjugated structure under mild conditions. Specifically, the decomposition method involves cleaving the main chain of the polymer compound through a conjugate substitution reaction with a nucleophilic agent, which is a compound that generates carboxylate ions, thiolate ions, amide ions, alkoxide ions, or phenolate ions. Furthermore, in the examples, the polymer compound is decomposed by stirring at room temperature for 24 hours in N,N-dimethylformamide solvent or without solvent. However, since the method is limited to polymer compounds having a conjugated structure, it cannot be said to be a general-purpose decomposition method.

[0014] Patent Document 7 discloses a method for producing recycled reinforcing fibers, which includes a step of treating a fiber-reinforced resin material containing reinforcing fibers and a resin component with a treatment liquid containing a solvent, and dissolving at least a portion of the resin component in the treatment liquid. The resin component is not particularly limited, and may be, for example, either a thermosetting resin or a thermoplastic resin, and various resin types are exemplified. It also indicates that acidic and basic substances can be used as catalysts, and that the catalyst content in the treatment solution can be 10% by weight or more and 50% by weight or less. It also indicates that various solvents can be used, and that one type can be used alone or two or more types can be used in combination. Here, "dissolution" is not limited to the direct dissolution of the resin component itself in the treatment solution, but also includes the decomposition of the resin component to generate a reaction product, which then dissolves in the treatment solution. In other words, the purpose is to "dissolve" various types of resins using a strongly acidic or strongly basic treatment solution containing a large amount of catalyst, and the selectivity of the decomposable resin type is not taken into consideration.

[0015] Most products used daily are not composed of a single compound but are in the form of a complex. Among these, urethane components are useful in that they contribute to adhesion with other components and can impart flexibility. Examples include cushioning for chairs and sofas, heat insulating materials for building materials, synthetic leather, urethane masks, articles coated with urethane paints, and laminated packaging films bonded with urethane adhesives. In particular, the manufacturing process of laminated packaging films generates a large amount of scrap material called "edges" where no adhesive is applied. Furthermore, a large amount of scrap material is left over after molding according to the product size. Currently, these scrap materials are discarded in large quantities without being recycled. Patent Document 8 discloses a method for recycling such multilayer films, including a plastic layer primarily composed of polyester (PET), polypropylene (PP), and polyethylene (PE) and an aluminum layer. Specifically, the aluminum in the multilayer film waste is selectively dissolved to induce layer separation, and the difference in specific gravity is used to separate the film into a PP / PE mixture layer and a PET layer. Furthermore, to increase the purity of the PET separated by the difference in specific gravity, an organic solvent is used to extract the PP and PE contained in the PET layer, thereby separating the main components of the multilayer film into PET, a PP / PE mixture, and the aluminum component. However, because a strong alkaline aqueous solution such as a sodium hydroxide solution is used to dissolve the aluminum layer, multiple water washings are required, which means that the number of steps required to recycle each constituent film of the multilayer film is large and consumes a lot of energy.

[0016] Urethane paints are also used in a wide range of applications, including construction, vehicles, and industrial applications. Traditionally, paint protects objects and repaints them as needed, extending their life cycle. However, little attention has been paid to the material recycling of coated objects, and they have often been disposed of as waste. Patent Document 9 discloses a method for recovering insoluble matter from a composite containing at least a cured resin that is soluble in a treatment liquid and an insoluble matter that is not soluble in the treatment liquid. It is disclosed that the treatment liquid preferably contains benzyl alcohol as a solvent and tripotassium phosphate as a catalyst. However, the use of highly solvent solvents has the disadvantage of easily damaging the substrate and shortening the life cycle of resources. There are also concerns about how to dispose of the solvents and the adverse effects on worker health. [Prior art documents] [Patent documents]

[0017] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-039908 [Patent Document 2] Japanese Patent Application Laid-Open No. 2012-131729 [Patent Document 3] Special Publication No. 2020-533395 [Patent Document 4] Japanese Patent Application Publication No. 2023-124421 [Patent Document 5] Japanese Patent Application Publication No. 7-145262 [Patent Document 6] Japanese Patent Application Publication No. 2022-168399 [Patent Document 7] International Publication No. 2022 / 118756 Brochure [Patent Document 8] Japanese Patent Application Laid-Open No. 2006-205160 [Patent Document 9] Japanese Patent Application Laid-Open No. 2013-234240 Summary of the Invention [Problem to be solved by the invention]

[0018] The present invention has been made in view of the above-mentioned background, and aims to provide a method for recycling materials to be treated that have constituent components containing specific chemical bonds. More specifically, the present invention aims to provide a recycling method involving separation and recovery of material parts from a composite having at least one or more chemical parts and at least one or more material parts. Here, the chemical part has at least one urethane bond, and also includes the case where it has at least one ester bond and / or carbonate bond in addition to at least one urethane bond. Hereinafter, complexes having components containing a urethane bond, an ester bond, or a carbonate bond as the main component may be abbreviated as "urethane complex," "ester complex," and "carbonate complex," respectively. [Means for solving the problem]

[0019] As shown in the above-mentioned prior art documents, it is known that the decomposition reaction of an ester composition or a carbonate composition can be promoted at a temperature of less than 100°C by combining the specific catalyst, nucleophile, and solvent used in the present invention. Meanwhile, the present inventors conducted extensive research to solve the above problems and found that the decomposition reaction of a urethane composition can also be promoted by further adjusting the combination of a specific catalyst, nucleophile, and solvent. They also found that the decomposition reaction of a urethane composition can be promoted at temperatures lower than those of conventional techniques, particularly at temperatures below 100°C. According to the present invention, the decomposition reaction of a urethane composition can be promoted without relying on a specific structure such as a conjugated structure.

[0020] Furthermore, the present inventors have found that the above-mentioned object can be achieved by applying the present invention to a composite. More specifically, the present inventors have found that, when the molar fractions of a treatment solution containing a specific catalyst, a nucleophile, and a solvent are X mol%, Y mol%, and Z mol%, respectively, relative to the total (where X + Y + Z = 100), by adjusting the molar ratio X / Y to 0.002 or more and the molar ratio Z / Y to 0.3 to 30, the decomposition reaction of a treatment target containing a component having at least one urethane bond (excluding those having a conjugated structure) proceeds at temperatures greater than 40°C and less than 100°C, thereby completing the present invention. Furthermore, the present inventors have found that, as a condition for higher catalytic activity, the decomposition reaction proceeds even at temperatures greater than 20°C and less than 40°C by adjusting the composition of the treatment solution so that the molar ratio X / Y is 0.10 or more and the molar ratio Z / Y is 0.3 to 30, both inclusive.

[0021] The treatment target (a) in the present invention can be exemplified by various targets as described below, but is preferably a composite having at least one chemical part (a1) and at least one material part (a2). That is, the chemical part (a1) is a composite containing a component having a specific chemical bond selected from the group consisting of a urethane bond, an ester bond, and a carbonate bond. More specifically, the chemical part (a1) is a composite containing a component having at least one urethane bond. Even more specifically, examples include a laminate film for packaging and a coated article. As the catalyst (b) in the present invention, various metal salts and nitrogen-containing organic base compounds can be used as described below, and are not particularly limited, but for example, at least one selected from the group consisting of alkali metal hydroxides, alkali metal alkoxides, and nitrogen-containing organic base compounds can be selected for implementation. More specifically, sodium hydroxide, sodium methoxide, and 1,5,7-triazabicyclo[4.4.0]dec-5-ene can be mentioned as examples. The nucleophilic agent (c) in the present invention is not particularly limited and at least one of various agents can be selected as described below, but is preferably a monohydric alcohol having 1 to 8 carbon atoms. More specifically, methanol can be given as an example. The solvent (d) in the present invention is not particularly limited and at least one of various solvents can be selected as described below, but is preferably an aliphatic and / or aromatic hydrocarbon solvent such as n-hexane, cyclohexane, mineral spirits, toluene, xylene, solvent naphtha, etc. More specifically, toluene can be given as an example. [Effects of the Invention]

[0022] According to the present invention, material recycling is possible through the decomposition reaction of the target material. More specifically, recycling is possible through the separation and recovery of material parts in the target composite material. This can also contribute to reducing carbon dioxide emissions. In particular, the decomposition reaction can be carried out at temperatures below 100°C, thereby reducing the energy consumption required for the decomposition reaction. Furthermore, in the present invention, it is sufficient to decompose the material part of the composite to an extent that it can be separated and recovered. Therefore, there is no need to completely decompose the chemical part of the composite down to the smallest monomer unit and then purify the decomposition product to remove impurities. This reduces the energy consumption and labor required for the series of processing steps. Furthermore, by adjusting the reaction conditions, damage to the material part being separated and recovered can be reduced, allowing for advantageous advances in material recycling. [Brief explanation of the drawings]

[0023] [Figure 1] FIG. 1 is a flow diagram of the process of the present invention. [Figure 2] 1 is a structural diagram of an apparatus for carrying out the present invention; [Figure 3] 1 shows the results of GPC in Reference Example 1-A of the present invention. [Figure 4]1 shows the results of GPC for Reference Example 4-A of the present invention and Comparative Reference Example 1-A.

[0024] In the GPC results, the horizontal axis represents retention time (minutes). Figures 3 and 4 show the results of multiple GPCs with the retention times aligned. DETAILED DESCRIPTION OF THE INVENTION

[0025] In the present invention, the nucleophilic substitution reaction of a specific chemical bond contained in the chemical part of the treatment target (a) can be carried out under conditions containing a catalyst (b), a nucleophile (c), and a solvent (d). The blending ratio of each of these components can be appropriately changed within the range in which the nucleophilic substitution reaction proceeds. Each component used in the present invention will be described in detail below, focusing on the composition of the "treatment liquid" containing the catalyst (b), the nucleophile (c), and the solvent (d). The molar fractions of the catalyst (b), the nucleophile (c), and the solvent (d) in the treatment liquid are X mol%, Y mol%, and Z mol%, respectively (X + Y + Z = 100). The raw materials exemplified in the following description do not limit the configuration of the present invention, and may be modified within the scope of the present invention.

[0026] <Processing target (a)> The treatment object (a) in the present invention is a complex composed of at least one or more chemical parts (a1) and at least one or more material parts (a2). Two or more types of treatment objects (a) can be mixed and used. Here, the chemical part (a1) is a component having at least one specific chemical bond (urethane bond, ester bond, carbonate bond). The material part (a2) does not inhibit the decomposition reaction of the chemical part (a1).

[0027] The following are examples of urethane composites, i.e., composites in which the target of treatment (a) of the present invention has a constituent component containing a urethane bond as a main component. Examples include soft urethane foams used for cushioning materials for chairs and sofas, bed mattresses, carpet backings, etc.; rigid urethane foams used for heat insulation materials, surfboard cores, etc.; thermoplastic urethane elastomers used as components of shoe soles, cable coverings, and decorative films; synthetic leathers; elastic fibers used in clothing; and paints and adhesives containing non-foam materials such as urethane resins as components.

[0028] The following are examples of ester composites, i.e., composites in which the target of treatment (a) of the present invention has a component containing an ester bond as a main component, such as polyester composites for food trays, fibers, adhesives, pressure-sensitive adhesives, inks, and coating films. To explain the polyester composite more specifically using the structure of a typical PET bottle as an example, it is composed of a bottle body, a cap, and a label. Here, the bottle body (main component: polyethylene terephthalate) corresponds to the chemical part (a1), and the cap (main component: polyethylene and / or polypropylene) and the label (main component: polystyrene) correspond to the material part (a2). These can be said to be composites in which two or more different components are physically combined without chemical bonding. In recent years, products in which PET bottles are compounded with polyamide resin to impart gas barrier properties have been adopted for wine and other beverages, but the present invention can be applied to such composites that physically contain additional substances. Since the present invention cannot decompose amide bonds, in the above example, polyethylene terephthalate, the raw material of PET bottles, decomposes, while the polyamide resin remains undecomposed. Similarly, examples of composites in which two or more different constituent components are physically combined without chemical bonding include those in which a vapor deposition layer is provided on the surface of a polyester product, and those in which a coloring component is mixed to impart a design. In either case, the ester component can be decomposed by applying the present invention.

[0029] Examples of carbonate composites, i.e., composites in which the target of treatment (a) of the present invention has a component containing a carbonate bond as a main component, are as follows: Examples include construction materials; transparent components for vehicles such as automobile window glass, headlight covers, and motorcycle windshields; eyeglass lenses; optical recording media such as optical disks; and resins for paints and adhesives.

[0030] Although the above examples have been given, there are no particular limitations on the shape or form of the object (a) to be treated in the present invention. For example, it can be in the form of a lump, fiber, film, pellet, etc. However, in order to achieve the object of the present invention of separating and recovering a material part (a2) from the object (a) to be treated and recycling the separated and recovered material part (a2), it is necessary to sufficiently react the treatment liquid containing the catalyst (b), nucleophile (c), and solvent (d) used in the present invention with the object (a) to be treated. To achieve this, it is preferable to process the object (a) to increase its surface area. It is also possible to use it without processing, but this would require a longer treatment time and consume more energy. Furthermore, since the present invention is intended for recycling, it is preferable to suppress the influence of impurities on the decomposition reaction, and it is preferable to wash and dry the object to be treated (a) before use. In particular, when considering material recycling, the object to be treated (a) may be contaminated with various types of dirt, such as dirt caused by dust and soil, oily dirt caused by fingerprints, sebum, and food, and dirt caused by organisms such as mold and algae, so it is preferable to provide a washing and drying step as a pretreatment.

[0031] <Chemical Part (a1)> The chemical part (a1) in the present invention is a component having at least one specific chemical bond (urethane bond, ester bond, carbonate bond). Therefore, components that do not contain the specific chemical bond but have other chemical bonds, such as ether bonds, amide bonds, imide bonds, urea bonds, azo bonds, carbon-carbon bonds, carbon-hydrogen bonds, carbon-halogen bonds, silicon-silicon bonds, etc., are not decomposed under the reaction conditions of the present invention and are therefore not included in the chemical part (a1). However, if a molecule contains the specific chemical bond, it is included in the chemical part (a1) even if other chemical bonds coexist in the same molecule. On the other hand, the material part (a2) is a component that does not contain the specific chemical bond. In the case of acrylic resins, polyvinyl acetate, partially saponified polyvinyl alcohol, etc., the main chain skeleton is not cleaved under the reaction conditions of the present invention, but the ester bonds in the side chain skeleton undergo transesterification, and therefore, these are included in the chemical part (a1).

[0032] To give a specific example of a resin composition used in a packaging laminate adhesive, a polyurethane composition consisting of a polyol composition and a polyisocyanate composition is generally used as the resin composition. Various compositions such as polyester polyol, polyether polyol, and polycarbonate polyol are used as the polyol composition depending on the application of the laminate film. That is, resin compositions such as polyester polyurethane, polyether polyurethane, and polycarbonate polyurethane are used as the adhesive. The adhesive may be water-based, solvent-based, or solventless, and may be one-component or multi-component. The adhesive layer may be formed by any of room temperature curing, heat curing, moisture curing, oxidative polymerization curing, and active energy ray curing.

[0033] When a PET film is included as a constituent film of a laminate film, the PET film corresponds to the chemical part (a1). Also, when an ink layer in a laminate film is formed containing any of a urethane bond, an ester bond, and a carbonate bond, the ink layer corresponds to the chemical part (a1). The components (decomposition products) and catalyst residues obtained by these decomposition reactions may be further decomposed by chemical recycling and reused as resources. On the other hand, nylon films, aluminum foils, vapor-deposited layers, etc. are not subject to the decomposition reaction under the reaction conditions of the present invention, and therefore do not fall under the category of the chemical part (a1).

[0034] <Material Part (a2)> Of the treatment target (a) in the present invention, the material part (a2) is a component that does not undergo decomposition under the reaction conditions of the present invention. More specifically, it is a component that does not contain any of urethane bonds, ester bonds, or carbonate bonds. That is, the material part (a2) is a component that does not inhibit the decomposition reaction of the chemical part (a1). Furthermore, it is a component whose composition is not chemically changed by the solvent (d). However, even if affected by swelling or dissolution by the solvent (d), components that can be recovered by volatilization of the solvent are included in the material part (a2).

[0035] The following is a more detailed explanation of the case where the treatment object (a) is a packaging laminate film. Examples include polyolefin films such as low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), high-density polyethylene (HDPE), biaxially oriented polypropylene (OPP), and unoriented polypropylene (CPP); metal films such as aluminum foil (AL); nylon (NY) films; cellulose films; polyphenylsulfide (PPS) films; polyimide (PI) films; vinyl chloride films; and fluororesin films such as PTFE. Paper films and polystyrene (PS) sheets can also be used. These films and sheets may have a vapor-deposited layer formed on them. They may also be colored. They may also be blends of multiple components or be produced by coextrusion or other methods.

[0036] There are no particular limitations on the method of use of the adhesive used in the packaging laminate film, and it can be used in a general lamination adhesive manner. Examples include a non-solvent lamination method in which the adhesive is heated to achieve an appropriate viscosity, and a dry lamination method in which a dilution solvent or other compounded adhesive is added to adjust the coating viscosity to an appropriate level. An active energy ray curable adhesive may also be used. The coating amount is 1 to 10 g / m2 in a dry state. 2 The temperature range is generally within this range, but it may be changed as appropriate depending on the type of each constituent film and the required performance depending on the application of the packaging laminate film. An aging period may also be set. For example, aging can be set at 20°C or higher and 50°C or lower for 2 days or higher and 5 days or lower.

[0037] In light of the above, a more specific embodiment of the composite (a) to which the present invention is preferably applied is a laminate film having the following configuration. Hereinafter, the polyester polyurethane adhesive will be abbreviated as "AD1" and the polyether polyurethane adhesive will be abbreviated as "AD2." However, AD2 does not contain an ester bond.

[0038] (Example 1)OPP / AD2 / CPP While AD2 containing a urethane component undergoes a decomposition reaction, OPP film and CPP film remain undecomposed according to the present invention and can therefore be separated and recovered. (Example 2) PET / AD1 / AL / AD1 / CPP PET film containing ester components and AD1 containing ester and urethane components undergo a decomposition reaction. Aluminum foil and CPP film remain undecomposed by the present invention and can be separated and recovered. (Example 3) PET / AD1 / AL / AD1 / NY / AD1 / CPP PET film containing ester components and AD1 containing ester and urethane components undergo a decomposition reaction. Aluminum foil, nylon film, and CPP film remain undecomposed by the present invention and can be separated and recovered. (Example 4) NY / AD1 / PE AD1, which contains ester and urethane components, undergoes a decomposition reaction. Nylon film and PE film remain undecomposed by the present invention, and can be separated and recovered.

[0039] Thus, the decomposition reaction according to the present invention is believed to lower the molecular weight of the cured adhesive film in the laminate film, weakening its interaction with the substrate. Furthermore, because the treatment is carried out in a solvent, the solvent can more easily penetrate into the areas where the interaction is weakened, which is believed to be advantageous for the separation and recovery of the substrate. Furthermore, the reaction conditions of the present invention do not impose excessive stress on the substrate, thereby suppressing deterioration of each component film that is separated and recovered. Specifically, discoloration, deterioration, deformation, etc. can be suppressed, making the film suitable for material recycling.

[0040] As described above, the case where the object to be treated (a) is a laminate film for packaging has been described as an example, but the present invention is not limited to this example. The present invention can also be applied to other objects such as coated articles, composite containers, home appliances, electrical and electronic parts, fiber-reinforced plastics, and textile products. Examples of the article to be coated include a multi-layer coating applied to a plastic bumper, and a powder coating applied to a metal part. Examples of composite containers include containers for beverages, cosmetics, paints, etc. These can be used even with caps or labels attached. Since the parts of home appliances and electrical / electronic components are bonded together with adhesives, they can be handled in the same way as packaging laminate films. Examples of fiber-reinforced plastics include glass fiber-reinforced plastics (GFRP), carbon fiber-reinforced plastics (CFRP), aramid fiber-reinforced plastics (AFRP), etc. Because they are lightweight and highly durable, they are used, for example, as building materials for bathtubs, washbasins, and other items, as well as for sporting goods such as golf clubs and tennis rackets, and as exterior materials for aircraft, automobiles, and other items. Examples of textile products include yarns, fabrics, clothing, bedding, rugs, curtains, towels, etc. These can also be applied with display labels, buttons, and zippers attached.

[0041] <Catalyst (b)> As the catalyst (b) of the present invention, metal salts and nitrogen-containing organic basic compounds can be suitably used. These catalysts can be used alone or in combination of two or more.

[0042] Examples of metal salts that can be used include hydroxides, carbonates, fatty acid salts, and alkoxides of alkali metals; hydroxides, carbonates, fatty acid salts, alkoxides, and oxides of alkaline earth metals; and hydroxides, carbonates, fatty acid salts, and alkoxides of transition metals. It is particularly preferable to use hydroxides and alkoxides of alkali metals. These catalysts can be used alone or in combination of two or more.

[0043] Examples of alkali metal hydroxides include lithium hydroxide, sodium hydroxide, and potassium hydroxide. Of these, sodium hydroxide is particularly preferred.

[0044] Examples of alkali metal alkoxides include lithium methoxide, lithium ethoxide, lithium tert-butoxide, sodium methoxide, sodium ethoxide, sodium tert-butoxide, potassium methoxide, potassium ethoxide, and potassium tert-butoxide. Of these, it is particularly preferable to use sodium methoxide.

[0045] Examples of nitrogen-containing organic base compounds include trimethylamine, triethylamine, tributylamine, pyrazole, imidazole, N-methylimidazole, benzimidazole, N-methylbenzimidazole, triazoles, benzotriazole, pyridine, quinoline, isoquinoline, triazines, 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD), 1,8-azabicyclo[5.4.0]undec-7-ene (DBU), and 1,3-dimesitylimidazol-2-ylidene. Among these, TBD is particularly preferred.

[0046] <Nucleophile (c)> As the nucleophilic agent (c) of the present invention, an alcohol can be used. Alternatively, an amine can be used. Among these, a monohydric alcohol having 1 to 8 carbon atoms is particularly preferred. The nucleophilic agent (c) is characterized by undergoing proton abstraction by the catalyst (b) to generate an anion, which then performs a nucleophilic attack on a urethane bond, an ester bond, or a carbonate bond, and is distinguished from the solvent (d) described below.

[0047] Examples of monohydric alcohols having 1 to 8 carbon atoms include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol (n-butanol), 2-butanol, tert-butanol, 2-ethylhexanol, and benzyl alcohol. Also usable are glycol monoalkyl ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol monohexyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, butylene glycol monomethyl ether, and butylene glycol monobutyl ether. These may be used alone or in combination of two or more. Among these, primary alcohols are preferred, and methanol is particularly preferred.

[0048] Examples of polyhydric alcohols having 1 to 8 carbon atoms include dihydric alcohols such as 1,2-ethanediol (ethylene glycol), 1,2-propanediol (propylene glycol), 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 2-methyl-1,2-propanediol, 1,2-hexanediol, 1,6-hexanediol, 2,5-hexanediol, 2-methyl-2,4-pentanediol, 1,2-cyclohexanediol, 1,3-cyclohexanediol, 1,4-cyclohexanediol, 1,8-octanediol, 2-ethyl-1,3-hexanediol, 1,2-benzenedimethanol, 1,3-benzenedimethanol, and 1,4-benzenedimethanol; and trihydric or higher alcohols such as trimethylolpropane, glycerin, erythritol, xylitol, and sorbitol.

[0049] The amine is not particularly limited, and monoamines and polyamines can be used. Amino alcohols can also be used. Examples of monoamines include primary amines such as n-butylamine, tert-butylamine, n-octylamine, 2-ethylhexylamine, aminomethylcyclohexane, and benzylamine; secondary amines such as di-n-butylamine, dioctylamine, di(2-ethylhexyl)amine, pyrrolidine, piperidine, and pyrrole; and tertiary amines such as triethylamine, tri-n-butylamine, tri-n-octylamine, and tri-2-ethylhexylamine. Examples of polyamines include ethylenediamine, 1,4-diaminobutane, 1,6-diaminohexane, 1,8-diaminooctane, 1,3-bisaminomethylcyclohexane, 1,4-bisaminomethylcyclohexane, 4-aminopiperidine, isophoronediamine, p-phenylenediamine, 2,4-tolylenediamine, 4,4'-diaminodiphenylmethane, diethylenetriamine, N,N'-dimethylethylenediamine, N,N'-dimethyl-1,2-diaminobutane, N,N'-dimethyl-1,4-diaminobutane, and piperazine. Examples of amino alcohols include aminoethanol, aminoethylethanolamine, dimethylaminoethanol, N,N-diethylethanolamine, N,N-dimethylethanolamine, N-ethyldiethanolamine, triethanolamine, and the like.

[0050] <Solvent (d)> The solvent (d) of the present invention can be appropriately selected as long as it does not inhibit the decomposition for material recycling, and examples thereof include aliphatic and / or aromatic hydrocarbon solvents such as n-hexane, cyclohexane, mineral spirits, toluene, xylene, and solvent naphtha; ketone solvents such as methyl ethyl ketone and methyl isobutyl ketone; ester solvents such as ethyl acetate, n-butyl acetate, isobutyl acetate, and ethylene glycol monomethyl ether acetate; carbonate solvents such as dimethyl carbonate and ethyl methyl carbonate; ether solvents such as dioxane, diethyl ether, and tetrahydrofuran; amide solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, and N-methyl-2-pyrrolidone; chlorine-containing solvents such as dichloromethane and trichloroethylene; sulfur-containing solvents such as dimethyl sulfoxide; and nitrogen-containing solvents such as acetonitrile and benzonitrile. These may be used alone or in combination of two or more. However, the use of alcohol-based or glycol ether-based solvents as the solvent (d) is excluded. For reasons described below, it is preferable to use an aliphatic and / or aromatic hydrocarbon solvent, and it is particularly preferable to use cyclohexane, toluene, or xylene.

[0051] The solvent (d) may be distilled and reused. However, in order to reduce the energy consumption required for the distillation operation, the boiling point of the solvent (d) is preferably 200°C or lower, more preferably 150°C or lower, and even more preferably 120°C or lower. However, if the boiling point of the solvent (d) is 40°C or lower, the reaction temperature cannot be increased, resulting in a longer reaction time. Also, the catalyst (b) is more likely to be deactivated, making it necessary to increase the amount of the catalyst (b) added.

[0052] The nucleophilic substitution reaction in the present invention is believed to be initiated by an anion generated by proton abstraction from the nucleophile (c) by the catalyst (b). That is, the amount of the catalyst (b) added contributes to the catalytic activity of the nucleophilic substitution reaction, and it is important to adjust the molar ratio of the catalyst (b) to the nucleophile (c). Specifically, the molar ratio X / Y of the catalyst (b) to the nucleophile (c) in the treatment liquid is preferably 0.002 or more, more preferably 0.01 or more, and even more preferably 0.10 or more. By setting the molar ratio within this range, the decomposition of the urethane composition can be achieved at temperatures below 100°C. Note that, when the decomposition of the urethane composition is to proceed in a low temperature range of 20°C or more to 40°C or less, it is necessary to further increase the catalytic activity, and the molar ratio X / Y is preferably 0.10 or more, and more preferably 0.20 or more. The amount of catalyst (b) added can be varied as appropriate depending on the size and shape of the object to be treated (a) and the reaction temperature. However, adding a large amount of catalyst (b) is undesirable because it increases costs. Furthermore, since the basicity of the treatment solution increases depending on the amount of catalyst (b) added, for example, if the material part (a2) contains aluminum, there is a risk of aluminum being deteriorated, which is undesirable from the viewpoint of material recycling. The molar ratio X / Y is preferably 1.0 or less, and more preferably 0.50 or less. On the other hand, adding a small amount of catalyst (b) may result in insufficient decomposition reaction due to deactivation.

[0053] In order to reduce the activation energy required for the nucleophilic substitution reaction in the present invention, it is preferable to use an aprotic solvent as the solvent (d). Although solvents with low polarity can be used, non-polar solvents such as n-hexane are thought to have poor compatibility with the anion generated by the proton abstraction of the nucleophile (c) by the catalyst (b), resulting in a decrease in catalytic activity. Since the nucleophilic agent (c) can also act as a protic polar solvent, it is important to adjust the molar ratio of the solvent (d) to the nucleophilic agent (c). Specifically, the molar ratio Z / Y of the solvent (d) to the nucleophilic agent (c) in the treatment solution is preferably 0.3 to 30, more preferably 0.5 to 25. Within this range, the amount of the solvent (d) added can be adjusted appropriately depending on the size and shape of the object to be treated (a). It can also be adjusted appropriately depending on the reaction apparatus. The contact area of ​​the object to be treated (a) with the solvent (d) is increased by processing it to an appropriate size. However, if the amount of the solvent (d) added is small, the contact with the catalyst (b) and the nucleophile (c) becomes insufficient, making it difficult for the decomposition reaction to proceed. If the amount of nucleophile (c) added is small, the decomposition reaction can be resumed by adding more nucleophile (c).

[0054] <Other ingredients (e)> In addition to the above (a) to (d), other components such as a desiccant and a component that is not involved in decomposition for material recycling may be included. These do not limit the configuration of the present invention, and may be added as appropriate within the scope of the present invention.

[0055] <Desiccant> Desiccants include physical desiccants and chemical desiccants, which can be used alone or in combination of two or more.

[0056] Physical desiccants include those that utilize the increased water and / or moisture transport path due to the matrix structure inside the desiccant, and those that utilize physical interactions such as adsorption of water and / or moisture with the desiccant.Specific examples include silica gel, molecular sieves, zeolites, and activated carbon.

[0057] Chemical desiccants include those that adsorb moisture and / or humidity through chemical reactions. Specific examples include metal oxides such as calcium oxide, barium oxide, and magnesium oxide; metal salts such as sodium sulfate, calcium sulfate, magnesium sulfate, calcium chloride, magnesium chloride, sodium carbonate, and potassium carbonate; diphosphorus pentoxide; silane compounds such as vinyltrimethoxysilane, dimethyldimethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, tetramethoxysilane, tetraethoxysilane, diphenyldimethoxysilane, and phenyltrimethoxysilane; and orthoester compounds such as methyl orthoformate, ethyl orthoformate, methyl orthoacetate, and ethyl orthoacetate.

[0058] The decomposition for material recycling of the present invention preferably proceeds at a temperature of 20° C. or higher but lower than 100° C., preferably 30° C. or higher but lower than 90° C., and more preferably 40° C. or higher but lower than 80° C. Although the decomposition for material recycling proceeds at temperatures below 20° C., the catalytic activity is insufficient. Furthermore, although the decomposition for material recycling proceeds at temperatures above 100° C., this is not preferable from the viewpoint of energy costs.

[0059] The material recycling decomposition of the present invention can be carried out under normal pressure or reduced pressure, but may also be carried out under pressure. The reaction time may be a time sufficient for separating and recovering material part (a2) from the treatment target (a), and may be, for example, 0.5 to 72 hours. If the interaction between the chemical part (a1) in the treatment target (a) and the material part (a2) is reduced by decomposition under the reaction conditions of the present invention, separation and recovery of the material part (a2) becomes easier. Therefore, the decomposition of the chemical part (a1) may be stopped before it has completely progressed.

[0060] Each step of the present invention will be described in detail below. Note that the steps illustrated in the following description are representative examples and may be modified within the scope of the present invention.

[0061] <Step 1: Pretreatment> Although pretreatment of the treatment target (a) in the present invention is not necessarily required before subjecting it to treatment, it is preferable to minimize the impact of impurities on the decomposition reaction. Therefore, it is preferable to separate components that can be easily physically separated in advance. Furthermore, since the treatment target (a) may be contaminated with various types of dirt, such as dirt caused by dust and soil, oily dirt caused by fingerprints, sebum, and food, and dirt caused by organisms such as mold and algae, it is preferable to include a washing and drying step as pretreatment. The shape or form of the object to be treated (a) is not particularly limited, and it can be in the form of, for example, a lump, fiber, film, pellet, etc. However, in order to achieve the object of the present invention of separating and recovering a material part (a2) from the object to be treated (a) and recycling the separated and recovered material part (a2), it is necessary to allow the catalyst (b), nucleophile (c), and solvent (d) used in the present invention to act sufficiently on the object to be treated (a). Therefore, it is preferable to process the object to be treated (a) to increase its surface area according to the size of the tank shown in Figure 2. It is also possible to repeat the series of steps, but it is preferable to wash and dry the bath before use in order to prevent secondary reactions. The following explanation will be given using a standing pouch for detergent or the like (typical film configuration: nylon film / polyether polyurethane adhesive / polyethylene film) as an example. If the pouch has a spout or a zipper for sealing, these may be removed. However, the present invention can be applied even if these accessories are not removed. It is preferable to process the laminate film constituting the pouch, such as by cutting it, depending on the size of the tank to be used. It is also preferable to wash and dry the pouch so that no content components or dirt components remain on the outer surface of the bottle.

[0062] <Step 2: Preparation> The target substance (a), nucleophile (c), and solvent (d), which have been pretreated as necessary, are added to the tank. The solvent (d) may be new or may be regenerated by distillation. However, when regenerating the solvent (d) by distillation, it is preferable to add a desiccant to adjust the water content. If the water content is high, the catalyst may be easily deactivated. Here, it is preferable to determine the amount of the solvent (d) to be added so that the object to be treated (a) is sufficiently immersed. The amount to be added may also be adjusted appropriately depending on the size of the tank.

[0063] <Step 3: Decomposition reaction> A catalyst (b) is added and the reaction is carried out at a predetermined temperature. The state of the object to be treated (a) in the tank is visually confirmed to evaluate the progress of decomposition for material recycling, and the reaction time can be adjusted accordingly. Specifically, the evaluation can be carried out by checking whether or not there is any remaining solid matter or whether or not there is any change in form. A portion of the tank can also be sampled for evaluation. Taking the example of a standing pouch for detergent, etc., as the decomposition of the cured film of polyether polyurethane adhesive progresses, the nylon film and the polyethylene film separate. Because these films have different specific gravities, changes in appearance occur as the decomposition progresses. The chemical part (a1) in the target (a) does not need to be completely decomposed, but only needs to be decomposed to the extent that the material part (a2) can be separated and recovered. Also, the progress of the material recycling decomposition can be restarted by adding the catalyst (b) or the nucleophilic agent (c).

[0064] <Step 4: Separation and recovery of catalyst residue and chemical part (a1)> When the catalyst residue or decomposition product resulting from the chemical part (a1) generated in the step 3 is in a solid state, it can be separated by ordinary filtration or hot filtration. The filter used for the filtration operation is not particularly limited, and the size and material can be selected appropriately. When the catalyst residue or decomposition product resulting from the chemical part (a1) generated in the step 3 is in a liquid state, it cannot be separated by a filtration operation. Therefore, it can be separated, for example, by a method of concentration and recrystallization or a method of extraction, but is not limited to these methods. To explain using the example of a standing pouch for detergent or the like, this step corresponds to the separation and recovery of catalyst residues and decomposition products generated by the decomposition reaction of the cured adhesive film. In the present invention, chemical recycling of these decomposition products, i.e., decomposition and purification for reuse as resources, is not essential, but chemical recycling decomposition for the purpose of reducing energy consumption and shortening the process is not excluded.

[0065] <Step 5: Separation and recovery of material part (a2)> The material part (a2) of the target (a) remains after step 4. If multiple material parts (a2) are mixed, they can be further separated according to previously reported methods, such as separation by specific gravity or dissolution in a specific solvent. Taking the example of a stand-up pouch for detergent, nylon film and polyethylene film fall into material part (a2). These films have different specific gravities, so they can be separated and recovered by immersing them in water.

[0066] <Embodiment of reaction device> Next, referring to FIG. 2, one embodiment of a reactor having a tank 1 (X) and a tank 2 and / or a path 10 (Y) will be described, but various types of reactors can be adopted and implemented.

[0067] The object to be treated (a) is placed in Tank 1 (X), which is surrounded by a filter that does not allow any solids to pass through, and the catalyst (b), nucleophile (c), and solvent (d) are placed in Tank 2 and / or Path 10 (Y), and (a) to (d) are mixed so that they come into contact with each other. Here, the object to be treated (a) in Tank 1 cannot pass through the filter surrounding Tank 1, but as the material recycling decomposition progresses, the structure is such that only the decomposition products dissolved in the reaction solution can pass through Tank 1. A heater 4 can be placed in Tank 2 as needed to adjust the reaction temperature.

[0068] Examples of mixing methods include stirring with a ceramic rotor, mechanical stirring with a stirring blade, and mixing by circulation. The example in Figure 2 shows an example of stirring using a stirring blade 5 at the tip of a rotating shaft connected to a motor 3. The liquid in the tank 2 and the liquid in a line 10 connected to the tank 2 are circulated by a pump 9 placed along the line, and in this example, a flow rate adjusting valve 6, a pressure gauge 7, and a filtration device 8 are placed in parallel along the line 10. The materials of the equipment used for recycling, such as the tank 1 (X), the tank 2 and / or the path 10 (Y), can be selected appropriately as long as they do not impede recycling. [Example]

[0069] The present invention will be explained in more detail below with reference to examples, but the present invention is not limited to the following examples.

[0070] In the examples shown below, the following raw materials were used unless otherwise specified. <Processing target (a)> The laminate film used had the following structure: Configuration 1:OPP / AD2 / CPP Configuration 2: NY / AD2 / CPP Configuration 3:AL / AD2 / NY Configuration 4: PET / AD1 / NY / AD1 / PE Configuration 5:PET / AD1 / NY / AD1 / AL / AD1 / CPP Here, AD1 and AD2 represent adhesives. AD1: Adlock RN-920 / HN-920 (manufactured by Rock Paint Co., Ltd.) was used as a polyester polyurethane adhesive. The cured film of this adhesive contains ester bonds and urethane bonds. AD2: Adlock RN-230 / HN-230 (manufactured by Rock Paint Co., Ltd.) was used as a polyether polyurethane adhesive. The main component, Adlock RN-230, contains urethane bonds but no ester bonds. The details of each constituent film are as follows: OPP film: Toyobo Co., Ltd., Pylen Film-OT P2241, thickness 25 μm CPP film: Toyobo Co., Ltd., Pylen Film-CT P1146, thickness 60 μm PET film: Toyobo Ester Film E5102, 12 μm thick, manufactured by Toyobo Co., Ltd. Nylon (NY) film: Unitika Ltd., Emblem ONBC-RT, thickness 15 μm Aluminum foil (AL): Toyo Aluminum Co., Ltd., thickness 20 μm PE film: RM Tocello Co., Ltd., TUX-FC-S, thickness 60 μm <Catalyst (b)> Sodium methoxide: Fujifilm Wako Pure Chemical Industries, Ltd., Wako First Grade Lithium methoxide: manufactured by Tokyo Chemical Industry Co., Ltd. Potassium methoxide: Fujifilm Wako Pure Chemical Industries, Ltd. Sodium tert-methoxide: manufactured by Tokyo Chemical Industry Co., Ltd. Sodium hydroxide: Kanto Chemical Co., Ltd., Grade 1 Potassium hydroxide: Kanto Chemical Co., Ltd. Calcium hydroxide: Special grade manufactured by Kanto Chemical Co., Ltd. 1,5,7-Triazabicyclo[4.4.0]dec-5-ene (TBD): manufactured by Tokyo Chemical Industry Co., Ltd. Sulfuric acid: Kishida Chemical Co., Ltd., special grade <Nucleophile (c)> Methanol: Fujifilm Wako Pure Chemical Industries, Ltd., ultra-dehydrated grade Ethanol: Fujifilm Wako Pure Chemical Industries, Ltd., ultra-dehydrated grade Isopropyl alcohol: Fujifilm Wako Pure Chemical Industries, Ltd., ultra-dehydrated grade n-Butanol: Fujifilm Wako Pure Chemical Industries, Ltd., special grade t-Butanol: Fujifilm Wako Pure Chemical Industries, Ltd., special grade Benzyl alcohol: manufactured by Tokyo Chemical Industry Co., Ltd. Ethylene glycol monobutyl ether: Tokyo Chemical Industry Co., Ltd. <Solvent (d)> Toluene: Special grade manufactured by Kanto Chemical Co., Ltd. Xylene: Fujifilm Wako Pure Chemical Industries, Ltd., special grade Methylcyclohexane: manufactured by Tokyo Chemical Industry Co., Ltd. n-Hexane: Special grade manufactured by Kanto Chemical Co., Ltd. Dimethyl carbonate: Kanto Chemical Co., Ltd., special grade MEK: Fujifilm Wako Pure Chemical Industries, Ltd. Dichloromethane: Special grade manufactured by Kanto Chemical Co., Ltd. Acetonitrile: Fujifilm Wako Pure Chemical Industries, Ltd., special grade N,N-Dimethylformamide (DMF): Special grade manufactured by Kanto Chemical Co., Ltd. <filter> · 0.5mm mesh, stainless steel

[0071] The method for producing a laminate film will be explained using the example of composition 1: OPP / AD2 / CPP. The dry coating amount is 4 g / m2 using a bar coater. 2 After applying AD2 to an OPP film and drying it, a CPP film was attached to the OPP film and nipped on a hot plate at 60° C. Then, the film was aged at 40° C. for 3 days. For other compositions, the dry coating weight should be 1 to 10 g / m depending on the type of film used and the intended use of the laminate film. 2 The range was adjusted appropriately.

[0072] [Evaluation Method] <GPC (Gel Permeation Chromatography)> The weight average molecular weight in the present invention is a value in terms of polystyrene by GPC. For example, the measurement conditions in the following examples are as follows: the temperature of the column (KF-805L×2 manufactured by Showa Denko K.K.) is 35°C, tetrahydrofuran (THF) is used as the eluent, the flow rate is 1.0 mL / min, detection is performed with a RI detector (differential refractometer), and the sample concentration is 0.3 mass%.

[0073] <FT-IR (Fourier Transform Infrared Spectroscopy)> For FT-IR, IRPrestige-21 manufactured by Shimadzu Corporation was used.

[0074] <Separation Rate> In the examples shown below, unless otherwise specified, the evaluation results were shown according to the following criteria. For laminate films composed of various film configurations, the degree of separation and recovery of each constituent film corresponding to the material part (a2), the remaining adhesive on each constituent film, and the damage to each constituent film were comprehensively judged visually. From the perspective of promoting the recycling of the composite, it is preferable that the material part (a2) is sufficiently separated from the treatment target (a). Therefore, ○△ or more was regarded as passing. 〇: Residual unseparated film less than 10%, no residual adhesive 〇△: Residual unseparated film 10% or more and less than 30%, almost no residual adhesive △: Residual unseparated film 30% or more and less than 70%, with residual adhesive ×: Residual unseparated film 70% or more, with residual adhesive ※: Damage to the constituent film (see the table annotation for details)

[0075] [Preliminary Study 1]​​​​​Rockbond J RU-40 (manufactured by Rock Paint Co., Ltd.) was used, which contains urethane bonds and ester bonds. [Main component of the polyether polyurethane adhesive (hereinafter referred to as AD4) used for verification] It was synthesized using the following manufacturing method. It contains urethane bonds and ether bonds, but does not contain ester bonds or carbonate bonds.

[0076] [AD4 main ingredient manufacturing method] Three polyalkylene glycols with different molecular weights, aromatic bifunctional isocyanate monomers, and a tin catalyst were added to a reaction vessel equipped with a nitrogen inlet tube, a stirrer, and a condenser. The mixture was allowed to react for 4 hours at an internal temperature of 80°C while stirring. FT-IR analysis confirmed that the absorption of the isocyanate group had completely disappeared, yielding the main component of AD4. The weight-average molecular weight was 3,800. The composition of the main component of AD4 can be schematically represented as in Chemical Formula 1 below. That is, it contains urethane bonds and ether bonds as chemical bonds other than carbon-carbon bonds (in the formula, R represents an aliphatic or aromatic hydrocarbon. R1, R2, and R3 represent aliphatic hydrocarbons. m1, m2, and m3 represent integers of 1 or greater. n1, n2, and n3 represent integers of 0 or 1, with one being 0 and the remaining two being 1. For example, when n3=0, n1=n2=1, indicating that no ether chain resulting from R3 is included).

[0077] [ka]

[0078] The degree of decomposition of the treatment object (a) was judged from the results of GPC before and after the reaction. Specifically, it was evaluated based on the change in molecular weight of the treatment object (a) according to the following criteria. <Evaluation criteria for the degree of decomposition> ○: Peaks derived from components before decomposition have disappeared, and peaks derived from constituent components have been detected. ○△: Peaks derived from the components before decomposition have almost disappeared, and peaks derived from the constituent components are detected. △: The peaks derived from the components before decomposition have become slightly sharper, but remain. △×: Peaks derived from constituent components are detected, but do not change significantly from the peaks derived from the components before decomposition. ×: No change from the peaks derived from the components before decomposition.

[0079] [Reference example 1-A] To a tank containing the main component of AD4 (6.00 parts by weight) as the treatment target (a), sodium methoxide (0.33 parts by weight) as the catalyst (b) and methanol (9.73 parts by weight) as the nucleophile (c) were added. Toluene (83.94 parts by weight) as the solvent (d) was added and stirred at 65°C for 2 hours. The molar ratio of the catalyst (b), nucleophile (c), and solvent (d) was 0.02:1:3. After the reaction was completed, the reaction solution was filtered, but no filtration residue was obtained. The filtrate was dried and the resulting components were analyzed by GPC. As shown in Figure 3, the peaks derived from the components before decomposition disappeared, and peaks derived from the constituent components were detected. The retention times of these peaks almost coincided with the peak retention times of the polyalkylene glycols that were the raw materials for the main component of AD4 (the degree of decomposition was evaluated as ○). From the above, it was determined that the urethane bond in the main component of AD4 had undergone a nucleophilic substitution reaction, i.e., the main component of AD4 had decomposed. Hereinafter, when an alkali metal alkoxide is used as the catalyst (b), the example will be suffixed with "A."

[0080] [Reference example 1-B] The molar ratio of the catalyst (b), the nucleophile (c), and the solvent (d) was fixed, and the main component of AD4 was treated in the same manner as in Example 1-A, unless otherwise specified, except that the catalyst (b) was changed to sodium hydroxide based on Reference Example 1-A. After the reaction was completed, the reaction solution was filtered, but no filtration residue was obtained. The filtrate was dried and the obtained components were analyzed by GPC. The results were the same as those shown in Figure 3, and it was determined that the main component of AD4 had decomposed (the degree of decomposition was evaluated as ○). Hereinafter, when a hydroxide is used as the catalyst (b), the example will be suffixed with "B."

[0081] [Reference examples 2-A, 3-A, 2-B, 3-B] In Reference Example 2-A, the molar ratio of the catalyst (b), the nucleophile (c), and the solvent (d) was fixed, and the treatment object (a) was changed to PET pellets based on Reference Example 1-A. Unless otherwise specified, the treatment was carried out in the same manner as Reference Example 1-A. After the reaction was complete, the reaction solution was filtered, but no filter residue was obtained. The filtrate was washed with water, and the organic layer was dried to obtain a solid. When the resulting components were analyzed by FT-IR, the peaks due to polyethylene terephthalate disappeared, and peaks due to dimethyl terephthalate were observed. Therefore, it was determined that the ester bonds in the polyethylene terephthalate had undergone alcoholysis, i.e., the PET pellets had decomposed. In Reference Example 3-A, when the reaction temperature was changed to 20°C based on Reference Example 2-A, the peak due to polyethylene terephthalate disappeared and a peak due to dimethyl terephthalate was observed, as in Reference Example 2-A. Therefore, it was determined that the PET pellets were decomposed even at 20°C. In Reference Examples 2-B and 3-B, the treatments were the same as in Reference Examples 2-A and 3-A, respectively, except that the catalyst (b) was changed to sodium hydroxide, unless otherwise specified. It was determined that the PET pellets decomposed when sodium hydroxide was used as catalyst (b), just as when sodium methoxide was used.

[0082] [Reference Example 4-A, Comparative Reference Example 1-A] In Reference Example 4-A, the molar ratio of the catalyst (b), the nucleophile (c), and the solvent (d) was fixed, and the treatment object (a) was changed to the main agent of AD3 based on Reference Example 1-A, except that the treatment was carried out in the same manner as Reference Example 1-A unless otherwise specified. After the reaction was completed, the reaction solution was filtered, but no filtration residue was obtained. The filtrate was dried and the resulting components were analyzed by GPC. As shown in Figure 4, the peaks due to the main component of AD3 disappeared, and peaks due to the constituent components were detected (the degree of decomposition was evaluated as ○). In addition, based on the results of Reference Examples 2-A and 3-A, it was determined that the ester bond contained in the main component of AD3 had also decomposed. On the other hand, in Comparative Reference Example 1-A, when the reaction temperature was changed to 20°C based on Reference Example 4-A, the peak due to the main component AD3 disappeared, but a broader peak remained in the higher molecular weight region than in Reference Example 4-A, as shown in Figure 4. Considering the results of Reference Examples 2-A and 3-A, it is thought that at 20°C, the urethane bond did not undergo nucleophilic substitution reaction, and only the ester bond did. In other words, it can be said that the nucleophilic attack on the urethane bond by nucleophile (c) proceeds more slowly than the nucleophilic attack on the ester bond.

[0083] [Reference Example 4-B, Comparative Reference Example 1-B] In Reference Example 4-B and Comparative Reference Example 1-B, the treatments were the same as in Reference Example 4-A and Comparative Reference Example 1-A, respectively, except that catalyst (b) was changed to sodium hydroxide, unless otherwise specified. When sodium hydroxide was used as catalyst (b), urethane bonds and ester bonds decomposed at 65°C, as in the case of using sodium methoxide, but at 20°C, only ester bonds decomposed and urethane bonds did not decompose.

[0084] [Table 1] <Preliminary study 2>

[0085] Next, the reaction conditions of the present invention were applied to the processing object (a) and the material part (a2). [Reference Examples 5 to 11, Comparative Reference Examples 3 to 4] Unless otherwise specified, the same procedure as in Reference Example 1 was carried out, except that the treatment object (a) and material part (a2) shown in Table 2 were used. A treatment solution (94.00 parts by weight) was used relative to the total of the treatment object (a) and material part (a2) (6.00 parts by weight). The composition of the treatment solution was fixed (the molar ratio of catalyst (b), nucleophile (c), and solvent (d) was 0.02:1:3).

[0086] In Reference Example 5, the treatment object (a) was a mixture of the main agent of AD4 and PET pellets. After the reaction was completed, the reaction solution was filtered, but no filtration residue was obtained. As in Reference Example 1, the mixture was analyzed by GPC and FT-IR, and it was determined that decomposition had also progressed in the mixed system of the urethane composition and the ester composition (the degree of decomposition was evaluated as ○).

[0087] In Reference Example 6, the treatment object (a): a mixture of the main agent of AD4 and the material part (a2): a nylon film. After the reaction was completed, the reaction solution was filtered, and only a nylon film was obtained. The nylon film obtained was not altered. Meanwhile, the filtrate was dried and the obtained components were analyzed by GPC, and it was determined that the main component of AD4 had decomposed, as in Reference Example 1 (the degree of decomposition was evaluated as ○). In Comparative Reference Examples 3 and 4, decomposition was attempted using only nylon film. In Comparative Reference Example 3, the reaction time was extended to 4 hours, and in Comparative Reference Example 4, the reaction temperature was raised to 110° C., but no change was observed in the nylon film. Therefore, it is considered that decomposition of amide bonds does not proceed under the reaction conditions of the present invention. Furthermore, even in a mixed system of the target (a) and the material part (a2), it can be said that the material part (a2) does not inhibit the decomposition of urethane bonds contained in the target (a).

[0088] In Reference Example 7, the treatment object (a) was a mixture of the main agent AD4 and nylon-composite PET. Here, the nylon-composite PET was a composite of PET pellets and Nylon-MXD6 (a crystalline polyamide obtained by polycondensation reaction of metaxylenediamine and adipic acid, manufactured by Mitsubishi Gas Chemical Company, Inc.) in a weight ratio of 95:5. The reaction solution was filtered, and the remaining unreacted nylon-composite PET was removed from the resulting residue. FT-IR analysis of the residue detected amide bonds originating from nylon-MXD6. Therefore, the processing object (a) and the material part (a2) It was also confirmed that decomposition proceeded in the synthetic system (degree of decomposition was rated as ○).

[0089] In Reference Example 8, decomposition was attempted using only a polycarbonate plate (PC plate). After the reaction was completed, the reaction solution was filtered, but no filter residue was obtained. The filtrate was dried and the resulting components were analyzed by GPC. The peaks derived from the components before decomposition disappeared, and peaks derived from the constituent components were detected. The retention times of these peaks almost coincided with the peak retention times of bisphenol A, the raw material for PC boards. From the above, it was determined that the carbonate bonds of the PC boards underwent a nucleophilic substitution reaction with methanol, and decomposition proceeded all the way to the raw material, bisphenol A. In Reference Example 9, the treatment object (a) was a mixture of the main agent of AD4 and PC board. After the reaction was completed, the reaction solution was filtered, but no filtration residue was obtained. As in Reference Example 5, decomposition of the urethane bond also progressed in the mixed system of the urethane composition and the carbonate composition (the degree of decomposition was evaluated as ○).

[0090] In Reference Examples 10 and 11, the treatment object (a): a mixture of the main agent of AD4 and the material part (a2): a PE film or aluminum foil was used. After the reaction was completed, the reaction solution was filtered, and only a PE film and an aluminum foil were obtained. These films were not altered. Meanwhile, the filtrate was dried and the resulting components were analyzed by GPC. As in Reference Example 1, it was determined that the main component of AD4 had decomposed (the degree of decomposition was evaluated as ○ in both cases).

[0091] [Table 2]

[0092] Table 1 lists the weight fraction and molar fraction of each component. Unless otherwise specified, the following discussion will be based on Reference Example 1, using the treatment target (a) (6.00 parts by weight) and treatment solution (94.00 parts by weight) and the molar ratios of the catalyst (b), nucleophile (c), and solvent (d) that make up the treatment solution. Furthermore, as shown in Table 2, the cases are divided according to the type of catalyst (b), with Pattern A representing sodium methoxide and Pattern B representing sodium hydroxide.

[0093] <1. Comparison of catalyst (b)> Based on the results of the above preliminary investigation, each component was investigated. First, the types of catalyst (b) were compared.

[0094] [Example 1-A] A laminate film of structure 1 (OPP / AD2 / CPP) was used as the treatment object (a). It was stirred for two hours at 65°C in a treatment solution containing sodium methoxide as the catalyst (b), methanol as the nucleophile (c), and toluene as the solvent (d). The cured film of adhesive AD2, the chemical part (a1) in the treatment object (a), decomposed and dissolved in the toluene. The reaction solution was filtered and washed with water, yielding OPP and CPP films. In other words, the OPP and CPP films, the material parts (a2) in the treatment object (a), were separated and recovered. No adhesive AD2 remained on these films, and no deterioration was observed. The separation rate was rated as ○. Similarly, when the laminated films of Configuration 2: NY / AD2 / CPP and Configuration 3: AL / AD2 / NY were examined, each constituent film could be separated and recovered in both cases. Furthermore, no adhesive AD2 remained in the separated and recovered films, and no deterioration was observed. The separation rate was rated ○.

[0095] [Examples 1-A-2 to 1-A-4] Unless otherwise specified, the laminate films of the above-mentioned structures 1 to 3 were treated in the same manner as in Example 1-A, except that the catalyst (b) was changed to a metal alkoxide of an alkali metal shown in Table 3. Regardless of the type of metal alkoxide of an alkali metal used as the catalyst (b), each of the constituent films could be separated and recovered. Furthermore, no adhesive AD2 remained in the separated and recovered film, and no deterioration was observed. The separation rate was evaluated as ○.

[0096] [Examples 1-B, 1-B-2, Comparative Example 1] In Examples 1-B and 1-B-2, the laminate films of the above-mentioned structures 1 to 3 were treated in the same manner as in Example 1-A, unless otherwise specified, except that the catalyst (b) was changed to sodium hydroxide and potassium hydroxide, respectively. Regardless of the type of alkali metal hydroxide used as the catalyst (b), each of the constituent films could be separated and recovered. Furthermore, no adhesive AD2 remained in the separated and recovered films, and no deterioration was observed. The separation rate was evaluated as ○. On the other hand, in Comparative Example 1, the laminate films of the above-mentioned structures 1 to 3 were treated in the same manner as in Example 1-B, except that the catalyst (b) was changed to calcium hydroxide. However, it was not possible to separate and recover each of the constituent films for any of the laminate films. This is thought to be due to the fact that when an alkaline earth metal hydroxide is used as the catalyst (b), the catalytic activity is lower than when an alkali metal hydroxide is used.

[0097] [Example 1-C] Except for changing the catalyst (b) to TBD, the laminate films of the above-mentioned structures 1 to 3 were treated in the same manner as in Example 1-A unless otherwise specified. Regardless of the type of alkali metal hydroxide used as the catalyst (b), each of the constituent films could be separated and recovered. Furthermore, no adhesive AD2 remained in the separated and recovered films, and no deterioration was observed. The separation rate was evaluated as ○.

[0098] Comparative Example 2 The laminate films of the above structures 1 to 3 were treated in the same manner as in Example 1-A, except that the catalyst (b) was changed to sulfuric acid. However, it was not possible to separate and recover the individual constituent films for the laminate films except for structure 1. In Example 1-A, it is believed that the nucleophilic substitution reaction of the urethane bond proceeds starting from proton abstraction from the nucleophile (c) by sodium methoxide. On the other hand, when sulfuric acid is used as a catalyst, it is believed that such proton abstraction is less likely to occur, making it difficult for the nucleophilic substitution reaction of the urethane bond to proceed.

[0099] Comparative Example 3 Unless otherwise specified, the laminate films of the above structures 1 to 3 were treated in the same manner as in Example 1-A, except that the catalyst (b) was not added. In all the laminate films, it was not possible to separate and recover the respective constituent films. It is believed that when the catalyst (b) was not added, proton abstraction from the nucleophile did not occur, and therefore the nucleophilic substitution reaction of the urethane bond did not proceed.

[0100] [Table 3]

[0101] <2. Comparison of nucleophiles (c)> Next, the types of nucleophiles (c) were compared.

[0102] [Examples 2 to 7] Unless otherwise specified, the laminate films of the above-mentioned compositions 1 to 3 were treated in the same manner as in Example 1, except that the nucleophilic agent (c) was changed to the alcohols shown in Table 4. In all cases except for Examples 4 and 5, in which n-butanol or t-butanol was used as the nucleophilic agent (c), each constituent film could be separated and recovered. Furthermore, no adhesive AD2 remained in the separated and recovered film, and no deterioration was observed. The separation rate was evaluated as ○. On the other hand, in Examples 4 and 5, the constituent films containing nylon film could not be separated and recovered for the aforementioned constituents 2 and 3. The reason for this is unclear, but it is thought that this is due to the fact that nylon has an amide bond, and therefore has an affinity for highly polar substances such as methanol, but a low affinity for n-butanol or t-butanol.

[0103] Comparative Example 4 Unless otherwise specified, the laminate films of the above-mentioned compositions 1 to 3 were treated in the same manner as in Example 1, except that the nucleophilic agent (c) was not added. However, in all the laminate films, it was not possible to separate and recover the individual constituent films. Here, methanol was not added as the nucleophilic agent (c), but when sodium methoxide was used as the catalyst (b) (Comparative Example 4-A), it could be decomposed by moisture in the air to produce methanol. However, since the amount of methanol that could be produced was small, it is thought that the nucleophilic substitution reaction of the urethane bond proceeded, and it was insufficient to separate and recover each constituent film. On the other hand, when sodium hydroxide was used as the catalyst (b) (Comparative Example 4-B), methanol could not be produced even when moisture in the air acted on it, and it is thought that the nucleophilic substitution reaction of the urethane bond did not proceed.

[0104] [Table 4]

[0105] <3. Comparison of solvents (d)> Next, the types of solvent (d) were compared.

[0106] [Examples 8 to 10] Unless otherwise specified, the laminate films of the above-mentioned compositions 1 to 3 were treated in the same manner as in Example 1, except that the solvent (d) was changed to a hydrocarbon solvent shown in Table 5. In Example 8, in which xylene was used as the solvent (d), and in Example 9, in which methylcyclohexane was used, each of the constituent films could be separated and recovered. Furthermore, no adhesive AD2 remained in the separated and recovered films, and no deterioration was observed. The separation rate was evaluated as ○. In Example 10, which used n-hexane, it was expected that separation would not proceed smoothly due to the low polarity of n-hexane and its poor compatibility with the anion generated by the proton abstraction of the nucleophile (c) by the catalyst (b). However, surprisingly, only the laminate film of the above-mentioned structure 1 was evaluated as × in separation rate, while only the laminate films of the above-mentioned structures 2 and 3 were evaluated as ○ in separation rate. Although the reason for this is unclear, it is thought that nylon, which has an amide bond, has a high affinity with highly polar methanol but a low affinity with n-hexane, which makes it easy for methanol to localize on the nylon film surface, facilitating the nucleophilic substitution reaction of the urethane bond.

[0107] [Examples 11 to 13] Unless otherwise specified, the laminate films of Configurations 1 to 3 were treated in the same manner as in Example 1, except that the solvent (d) was changed to a non-hydrocarbon solvent shown in Table 5. When a non-hydrocarbon solvent was used, it was not possible to separate and recover the constituent films of the laminate film of Configuration 1, and the separation rate was evaluated as x. This is thought to be due to the fact that hydrocarbon solvents have an affinity for hydrocarbon films, whereas non-hydrocarbon solvents have a low affinity for hydrocarbon films, making it difficult for the nucleophilic substitution reaction of the urethane bond to proceed.

[0108] [Example 14] When the solvent (d) was changed to dichloromethane and the laminate films of the above structures 1 to 3 were treated in the same manner as in Example 1, the separation and recovery of each constituent film of the laminate film of the above structure 1 was insufficient, and the separation rate was evaluated as △. The separation and recovery of each constituent film of the laminate film of the above structures 2 to 3 was possible, and the separation rate was evaluated as ○. As in Examples 11 to 13, this is thought to be due to the low affinity between dichloromethane and hydrocarbon-based films. In addition, dichloromethane has a low boiling point, and its boiling point only rises to 40°C when heated, which is thought to be due to the fact that sufficient catalytic activity was not obtained. In Example 14, the amount of catalyst was increased five times compared to the results of the above study, and the constituent films of the laminated film of Structure 1 were separated and recovered, and the separation rate was improved to a rating of ○.

[0109] Comparative Example 5 The laminate films of the above structures 1 to 3 were treated in the same manner as in Example 1, except that the solvent (d) was not added. However, it was not possible to separate and recover any of the laminate films. This is thought to be because methanol also acts as a protic solvent, stabilizing the anion generated by the catalyst (b) abstracting the proton of the nucleophile (c), thereby increasing the activation energy required to proceed with the nucleophilic substitution reaction of the urethane bond. Furthermore, deterioration of the aluminum foil was observed in the laminate film containing aluminum foil according to the third embodiment. This is thought to be due to the fact that the catalyst concentration was increased because the solvent (d) was not included.

[0110] [Table 5]

[0111] <4. Comparison of reaction temperatures> Next, the reaction temperature was compared.

[0112] [Comparative Examples 6 to 7] As shown in Table 6, the laminate films of the above-mentioned compositions 1 to 3 were treated in the same manner as in Example 1, except that the reaction temperature was changed to 20°C or 40°C, unless otherwise specified. In all the laminate films, it was not possible to completely separate and recover each of the constituent films. The separation rates were evaluated as fair to poor. It is believed that the catalytic activity could not be sufficiently increased in the low temperature range of 20°C to 40°C.

[0113] [Examples 15 to 20] Unless otherwise specified, the laminate films of the above structures 1 to 3 were treated in the same manner as in Example 1, except that the reaction temperature was set to 20°C, 40°C, and 65°C, and the amount of catalyst (b) added was changed as shown in Table 6. As the amount of catalyst added increased, the evaluation of the separation rate improved from △ to ○. However, when sodium methoxide was used as the catalyst (b), if the amount of catalyst added was too large, deterioration of the aluminum foil was observed in the laminate film of the above structure 3 containing aluminum foil (Examples 18-A to 20-A).

[0114] [Table 6]

[0115] <5. Comparison of the composition of processing solutions> Next, the compositions of the treatment solutions were compared.

[0116] [Examples 21 to 27, Comparative Examples 8 to 9] Unless otherwise specified, laminate films of the structures 1 to 3 were treated in the same manner as in Example 1, except that the molar ratio of the catalyst (b) and the nucleophile (c) was fixed and the molar ratio of the solvent (d) was changed as shown in Table 7. The separation rate clearly differed depending on the molar ratio Z / Y of the solvent (d) and the nucleophile (c). It is believed that the nucleophilic substitution reaction of the urethane bond proceeds starting from an anion generated when the catalyst (b) abstracts a proton from the nucleophile (c). However, when the molar ratio Z / Y is large, i.e., when the amount of the solvent (d) is high relative to the amount of the nucleophile (c), it is believed that the separation rate deteriorates due to the influence of a decrease in the concentration of the anion. On the other hand, when the molar ratio Z / Y is small, that is, when the amount of the solvent (d) is small relative to the amount of the nucleophile (c), the proportion of the nucleophile (c) acting as a protic solvent becomes relatively large, which is thought to have increased the activation energy of the nucleophilic substitution reaction on the urethane bond, thereby causing a deterioration in the separation rate.

[0117] [Table 7]

[0118] [Examples 28 to 33, Comparative Examples 10 to 12] The molar ratio of the catalyst (b) was fixed, and the total molar ratio of the nucleophile (c) and the solvent (d) was fixed. The molar ratios of the nucleophile (c) and the solvent (d) were changed as shown in Table 8. The laminate films of the configurations 1 to 3 were treated in the same manner as in Example 1, unless otherwise specified. The separation rate clearly differed depending on the molar ratio Z / Y of the solvent (d) and the nucleophile (c). This is thought to be due to the same reasons discussed in Examples 21 to 27 and Comparative Examples 8 and 9.

[0119] [Table 8]

[0120] [Examples 33 to 35, Comparative Example 13] The laminate films of the structures 1 to 3 were treated in the same manner as in Example 1, except that the molar ratio of the nucleophile (c) and the solvent (d) was fixed and the molar ratio of the catalyst (b) was changed as shown in Table 9, unless otherwise specified. At 65°C, even when the catalyst amount was 1 / 10 and 1 / 2 of that in Example 1, the separation rates were evaluated as Good and Good (Examples 34 and 35). On the other hand, as shown in Examples 17 and 20, when the amount of catalyst (b) added increased, deterioration of the aluminum foil was observed in Configuration 3, which includes aluminum foil. From the above, in order to promote material recycling, it is necessary to set the amount of catalyst appropriately.

[0121] [Table 9]

[0122] As shown in the results in Tables 3 to 9, a treatment solution containing a specific catalyst (b), a nucleophile (c), and a solvent (d) was prepared for a treatment object (a) having at least one urethane bond, and the molar ratio of the catalyst (b) and the solvent (d) to the nucleophile (c) was set within a specific range, thereby enabling the decomposition of the urethane bond.

[0123] <6. Comparison of processed object (a)> Finally, the following three types of treatment object (a) were compared. (1) Configuration 4: PET / AD1 / NY / AD1 / PE laminate film (2) Configuration 5: PET / AD1 / NY / AL / AD1 / CPP laminate film (3) Painted object: Multi-layer paint film applied to a plastic bumper

[0124] The coated article was prepared in the following manner. [Preparation of the object to be coated] A polypropylene-based bumper (PP bumper) was coated with Resin Parts Eco Primer II Clear (Rock Paint Co., Ltd., 051-4F55) to a thickness of 5-10 μm and dried at room temperature for 30 minutes. On top of that, Hi-Lock ECO Z Black / Hi-Lock ECO Hardener (Rock Paint Co., Ltd., 073-5250 / 073-5110, acrylic polyurethane paint) was coated to a thickness of 30-35 μm and dried at room temperature for 30 minutes. Eco-Lock Hyper Clear S / Eco-Lock Hardener (Standard Type) (Rock Paint Co., Ltd., 149-6150 / 149-6120) was coated on top to a thickness of 45-55 μm and dried at 60°C for 30 minutes to produce a multi-layer coating. The coating was cut to fit into the tank to obtain coating pieces.

[0125] [Examples 36 to 40, Comparative Examples 13 to 14] The treatment was carried out in the same manner as in Table 7, except that the above (1) to (3) were used as the treatment object (a). In Examples 36 to 40, the molar ratio X / Y was 0.002 or more, and the molar ratio Z / Y was in the range of 0.3 to 30. When the laminate film of the above-mentioned configuration 4 was used, the PET film and AD1 were decomposed, and the NY film and PE film could be separated and recovered. No deterioration was observed in any of the separated and recovered films. When the laminate film of the above-mentioned configuration 5 was used, the PET film and AD1 were decomposed, and the NY film, aluminum foil, and CPP film were separated and recovered. No deterioration was observed in any of the separated and recovered films. When the above-mentioned coated article was used, the urethane resin component in the coating was decomposed, and the PP bumper could be separated and recovered without any remaining coating. No deterioration was observed in the separated and recovered PP bumper. On the other hand, in Comparative Examples 13 and 14, the molar ratio X / Y was 0.002 or more, but the molar ratio Z / Y was outside the range of 0.3 to 30, and decomposition of the urethane bond was insufficient in any of (1) to (3).

[0126] [Table 10]

[0127] [Examples 41 to 44, Comparative Example 15] The treatment was carried out in the same manner as in Table 8, except that the above (1) to (3) were used as the treatment object (a). In Examples 41 to 44, the molar ratio X / Y was 0.002 or more and the molar ratio Z / Y was in the range of 0.3 to 30, and the results were similar to those of Examples 36 to 40. On the other hand, in Comparative Example 15, the molar ratio X / Y was 0.002 or more, but the molar ratio Z / Y was outside the range of 0.3 to 30, and decomposition of the urethane bond was insufficient in any of (1) to (3).

[0128] [Table 11] [Examples 45 to 48] The treatment was carried out in the same manner as in Table 9, except that the above (1) to (3) were used as the treatment object (a). In Examples 41 to 44, the molar ratio X / Y was 0.002 or more and the molar ratio Z / Y was in the range of 0.3 to 30, and the results were similar to those of Examples 36 to 44. However, under conditions where the amount of catalyst was large as in Example 48, deterioration of the aluminum foil was observed in Configuration 5, which included the aluminum foil. On the other hand, in Comparative Example 16, the molar ratio X / Y was 0.002 or more, but the molar ratio Z / Y was outside the range of 0.3 to 30, and decomposition of the urethane bond was insufficient in any of (1) to (3).

[0129] [Table 12]

[0130] As shown above, even for laminate films with multiple films stacked on top of each other and coated articles, it was possible to separate and recover the material part (a2) from the treatment object (a) under the reaction conditions of the present invention. [Explanation of symbols]

[0131] 1 tank 2 tanks 3 motors 4 Heater 5 Mixing blades 6 valves 7. Pressure gauge 8. Filtration equipment 9. Pump

Claims

1. A recycling method involving decomposition of urethane bonds in a treatment object (a) using a treatment liquid, comprising: The treatment target (a) is a complex composed of a chemical part (a1) and a material part (a2), The chemical part (a1) is a component having at least one urethane bond (excluding those having a conjugated structure), the material part (a2) is not bonded to the chemical part (a1) via a chemical bond, the treatment liquid contains a catalyst (b), a nucleophilic agent (c), and a solvent (d); When the molar fractions of the catalyst (b), the nucleophilic agent (c), and the solvent (d) relative to the total amount are X mol %, Y mol %, and Z mol %, respectively (where X + Y + Z = 100), the molar ratio X / Y is 0.002 or more, and the molar ratio Z / Y is 0.3 or more and 30 or less, decomposition of the urethane bond proceeds at a temperature higher than 40°C and lower than 100°C; The material part (a2) remaining without being decomposed from the treatment object (a) is separated and recovered. Recycling methods.

2. A recycling method involving decomposition of urethane bonds in a treatment object (a) using a treatment liquid, comprising: The treatment target (a) is a complex composed of a chemical part (a1) and a material part (a2), The chemical part (a1) is a component having at least one urethane bond (excluding those having a conjugated structure), the material part (a2) is not bonded to the chemical part (a1) via a chemical bond, the treatment liquid contains a catalyst (b), a nucleophilic agent (c), and a solvent (d); When the molar fractions of the catalyst (b), the nucleophilic agent (c), and the solvent (d) relative to the total amount are X mol %, Y mol %, and Z mol %, respectively (where X + Y + Z = 100), the molar ratio X / Y is 0.10 or more, and the molar ratio Z / Y is 0.3 or more and 30 or less; decomposition of the urethane bond proceeds at a temperature of 20°C or higher and lower than 100°C, The material part (a2) remaining without being decomposed from the treatment object (a) is separated and recovered. Recycling methods.

3. the chemical part (a1) is a component having at least one urethane bond (excluding those having a conjugated structure), Furthermore, it is characterized in that it has at least one ester bond and / or carbonate bond. The recycling method according to claim 1 or 2.

4. The catalyst (b) is at least one selected from the group consisting of alkali metal hydroxides, alkali metal alkoxides, and nitrogen-containing organic basic compounds. The recycling method according to claim 1 or 2.

5. The catalyst (b) is at least one selected from the group consisting of sodium hydroxide, sodium methoxide, and 1,5,7-triazabicyclo[4.4.0]dec-5-ene. The recycling method according to claim 4.

6. The nucleophilic agent (c) is a monohydric alcohol having 1 to 8 carbon atoms. The recycling method according to claim 1 or 2.

7. The nucleophilic agent (c) includes at least one selected from the group consisting of methanol, ethanol, isopropyl alcohol, benzyl alcohol, and ethylene glycol monobutyl ether. The recycling method according to claim 6.

8. The solvent (d) contains an aliphatic and / or aromatic hydrocarbon solvent. The recycling method according to claim 1 or 2.

9. The solvent (d) contains at least one selected from the group consisting of cyclohexane, toluene, and xylene. The recycling method according to claim 8.

10. The treatment object (a) is at least one selected from the group consisting of a packaging laminate film, a coated article, a composite container, a home appliance, an electric / electronic part, a fiber-reinforced plastic, and a textile product. The recycling method according to claim 1 or 2.

11. The treatment object (a) does not contain a component having an amide bond and does not contain a metal component. The recycling method according to claim 1 or 2.

12. At least three steps: A step of carrying out a decomposition reaction; A step of separating and recovering the catalyst residue and the chemical part (a1); A step of separating and recovering the material part (a2); characterized in that it comprises The recycling method according to claim 1 or 2.

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