Method for separating and recovering plastic film, and method for producing recycled plastic pellet

Abstract

To provide a method for easily separating and recovering a base material (plastic film) constituting a laminate, consisting of at least two base materials laminated together, and a method for producing high-quality recycled plastic pellets using plastic crushed material recovered by the method, in the laminate, which can improve a peelability of the laminate.SOLUTION: A method for separating and recovering a laminate having at least an adhesive layer and a removable primer layer between a resin substrate A and a resin substrate B includes steps of: (1) crushing the laminate; (2) immersing the laminate in a cleaning solution containing an inorganic base; and (3) separating the crushed laminate into a single layer of crushed plastic by agitating the crushed laminate in the presence of a liquid.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a method for separating and recovering plastic films, and a method for producing recycled plastic pellets using the plastic crushed materials recovered by the method.

Background Art

[0002] Currently, the recycling rate of separately collected plastic waste is 9% of the total plastics produced globally. Among the 91% of plastics that become waste, 12% are incinerated, and 79% are landfilled or leaked into the environment (Non-Patent Document 1). One of the reasons for the low recycling rate is the difficulty of the separation and collection system. In order to recycle plastics, it is necessary to separate and recover waste plastics in which different plastic materials such as polyethylene (PE) and polypropylene (PP) are integrated, by material. However, many plastic products, including laminated films, have different plastic materials adhered and laminated, making it difficult to separate and recover them by material. Therefore, there is a strong demand for the construction of a recycling system that can easily separate and recover waste plastics.

[0003] In addition, recycled plastic products are difficult to return to the same products from a cost perspective, and basically deteriorate every time they are recycled, so they have to be reborn as products with lower quality. The reason for the deterioration of the quality of recycled plastics is that inks and pigments are mixed in plastics as impurities. However, since many plastic products are printed on their surfaces, it is difficult to decolorize them in the recycling process, and as a result, recycled plastic products are colored. Recycled plastics containing pigments and inks not only have significantly low commercial value due to coloring, but in fact, they can only become plastics that have deteriorated physically with impurities as the starting point, and a recycling method for producing high-quality recycled plastics is also demanded.

[0004] In response to such problems, Patent Document 1 proposes a method of separating and recycling valuable components by dissolving an aluminum layer of a crushed multilayer film with an alkali, separating the multilayer film by a specific gravity difference, and further selectively melting it in a solvent. Patent Document 2 proposes a process of crushing, ink removal, rinsing, and drying a printed film, but both processes are long and complicated.

[0005] In addition, Patent Document 3 provides a method of removing ink from a film in a printed roll state using a solvent and a non-abrasive cloth, and Patent Document 4 provides a method of removing ink from a film in a printed roll state using a solvent, a brush, and a wiper blade. However, these methods only produce a non-printed film with the ink removed from the film in the roll state.

[0006] Especially in recent years, with the diversification of packaging materials, there is an increasing demand for the high functionality of packaging materials, the improvement of the adhesion of the ink film to the plastic substrate, and the high design quality of printed matter. Therefore, the types of packaging materials and inks have become more diverse. At the same time, it has become more difficult to peel the ink layer (printing layer). For example, in a laminate in which a plurality of films are laminated via an adhesive layer, or a laminate in which a printing layer is provided on a film and then another film or the like is laminated via an adhesive layer, it is difficult to separate the laminate. Also, in the case of a laminated film with a printing layer provided between a plurality of films (reverse printing), since separating a plurality of films is required to remove the printing layer, it becomes more difficult to peel the printing layer. In response to such problems, a packaging material is known in which a detachable primer layer is provided on a substrate, and the printing layer formed on the primer layer can be removed. For example, Patent Document 5 discloses a packaging material having excellent detachability of a printing substrate and capable of removing a printing layer, which includes a first substrate, a primer layer, a printing layer, and a second substrate in this order.

[0007] However, in order to separate and recover a laminate of a plurality of films and recycle it as high-quality recycled plastic, an improvement in the peelability of the laminate is desired.

Prior Art Documents

Non-Patent Documents

[0008]

Non-Patent Document 1

Patent Documents

[0009]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Summary of the Invention

Problems to be Solved by the Invention

[0010] In the prior art, in the method for separating a laminated film, after the step of dry-crushing the laminated film, an ink removal or separation step is carried out. That step is common, and the process is long and complicated. Further, with the prior art method, it is difficult to recycle laminated films with various configurations, which reduces the quality and commercial value of recycled plastics.

[0011]

[0012] ​Therefore, the problem to be solved by the present invention is to provide a method capable of improving the peelability of a laminate in which at least two base materials are laminated, easily separating and recovering the base materials (plastic films) constituting the laminate, and a method for producing high-quality recycled plastic pellets using the plastic crushed materials recovered by the method.

Means for Solving the Problem

[0013] As a result of intensive research to solve the above-described problems, the present inventors have found an easy method for separating and recovering a laminate having at least two base materials, which includes a step 1 of crushing the laminate, a step 2 of immersing the laminate in a cleaning liquid, and a step 3 of separating the laminate by stirring the crushed laminate in the presence of a liquid, and can recycle the laminate into a high-quality recycled raw material.

[0014] That is, the present invention provides a method for separating and recovering a laminate having at least an adhesive layer and a release primer layer between a resin base material A and a resin base material B, which includes a step 1 of crushing the laminate, a step 2 of immersing the laminate in a cleaning liquid containing an inorganic base, and a step 3 of separating the laminate into single-layer plastic crushed materials by stirring the crushed laminate in the presence of a liquid.

[0015] The present invention also provides a method for producing recycled plastic pellets, in which the plastic crushed materials separated by the method described above are recovered layer by layer, and the recovered materials are melted and then formed by a molding machine.

Effects of the Invention

[0016] According to the present invention, a laminate in which at least two base materials are laminated can be separated into single layers, and the crushed single-layer films can be easily recovered, sorted, and reused. According to the method of the present invention, in a plastic laminate having various structures such as a laminated film in which two base materials are laminated via an adhesive layer and a printing layer is further provided between a plurality of films (reverse printing), the plastic laminate can be separated into single layers, and the printing layer can be easily peeled off. That is, since the film can be separated into single layers and the printing layer can be easily peeled off, the separation and recovery method of the plastic laminate can be facilitated, and the recovered plastic can be reused as a high-quality recycled plastic raw material.

Embodiments for Carrying Out the Invention

[0017] <Regarding Step 1> The method for separating and recovering the laminate of the present invention includes Step 1 of crushing the laminate. In Step 1, the method of crushing the laminate is not particularly limited and can be performed by a known method. Further, the crushing may be performed in an air atmosphere in which no liquid such as a solvent is present, or in water or a cleaning liquid. When performing crushing in an air atmosphere, a dry crusher can be used. Further, when performing crushing in water or a cleaning liquid, a wet crusher capable of performing pressure feeding simultaneously with crushing can be used. When a wet crusher is used, the laminate can be efficiently crushed, and the laminated plastic film can be peeled off into each layer.

[0018] By crushing the laminate in Step 1, it becomes easier to completely peel the laminate into single layers in Step 2 and Step 3 described later. In Step 1, it is sufficient that the laminate is crushed, and the crushed laminate may be in a state where at least a part such as an end is partially peeled, or each layer may be completely peeled, or each layer may not be peeled.

[0019] The long side of the laminate crushed in Step 1 is preferably 1 mm to 30 mm, more preferably 1 mm to 20 mm, and even more preferably 1 mm to 10 mm. When within the above range, in Step 2 of immersing the laminate in the cleaning liquid, the time for the treatment liquid to penetrate from the end face to the center of the fluff is shortened, and the laminate can be easily peeled into a complete single layer.

[0020] In terms of shortening the time for the treatment liquid to penetrate from the end face to the center of the fluff, it is more preferable that holes or cuts are formed in the crushed laminate. The diameter of the holes or the length of the cuts is preferably 0.5 mm or more, more preferably 0.8 mm or more, and even more preferably 1.0 mm or more.

[0021] (Dry crusher) The dry crusher used in Step 1 is not particularly limited. For example, jaw crusher, impact crusher, cutter mill, stamp mill, ring mill, roller mill, jet mill, hammer mill, colloid mill, rotary cutter, microcollider, macrocollider, ball mill, power mill, pin mill, pneumatic pulverizer (jet mill), shear friction type pulverizer, cutter type pulverizer, impact type pulverizer (hammer mill, ball mill), roll type pulverizer, homogenizer, ultrasonic crusher, etc., and known technologies for pulverizing solids or cutting films can be applied. In order to prevent the base material or the printing layer from softening due to frictional heat during crushing and the cross-section of the laminate from fusing, it is preferable to flow cooling water at 40°C or lower through the laminate or the crushing device and perform crushing in a cooled state so that the temperature does not exceed 100°C.

[0022] The dry crusher can be preferably used when separating and recovering a plastic film with a printed layer provided on the film surface (front printing) or a plastic film with a printed layer and a coating layer covering the printed layer provided on the film surface. It can also be preferably used when performing separation and recovery from Step 1 to Step 4. The printed layer applied to the plastic film is a printing layer for imparting display such as product names and decorativeness, and is often printed using a gravure printing machine, a flexographic printing machine, an offset printing machine, an inkjet printing machine, etc., with organic solvent-based printing ink, water-based or active energy ray-curable ink. In such a plastic film provided with such a printed layer, when using a dry crusher in Step 1, the laminate and the printed surface are not completely separated. However, in the present invention, in Steps 2 and 3 described later, the base material (film) constituting the laminate can be separated, and further, the base material (film) and the printed surface can be completely separated. In a laminate in which the printed layer is provided between a plurality of films (back printing), in addition to the dry crusher, a wet crusher can be used.

[0023] (Wet crusher) The wet crusher used in Step 1 is not particularly limited, but a wet crusher capable of simultaneously crushing, dispersing, mixing, and pumping solids in a liquid is preferable. Specifically, those having a mechanism for crushing solids in a liquid by shear force and / or frictional force are preferable, and crushers having a mechanism for crushing and pumping a laminate are preferable. Examples of such wet crushers include wet crushing pumps, colloid mills, attrition mills, and beating machines.

[0024] (Wet crushing pump) The wet crushing pump preferably has a mechanism for crushing solids with a fixed blade and a rotating blade while pumping the solids in a liquid. A more preferable mechanism is a mechanism in which the solids are crushed in three stages by a combination of four components: a cutting blade, a crushing impeller, a shroud ring, and a grid.

[0025] With a wet crushing pump, the laminate is crushed in three stages. The laminate is roughly cut by the cutting edge of the fixed blade and the edge of the inlet of the crushing impeller of the rotating blade, then agitated and pumped by the axial-flow type crushing impeller, and part of the laminate hits the blade part of the shroud ring of the fixed blade and is cut. The laminated film that has passed through the crushing impeller is further finely crushed and agitated between the grids, pressurized by the pressurizing impeller through the grids, and pumped to the next process.

[0026] The pumping speed is not particularly limited, but considering the peeling of the printing layer and the peeling and separation efficiency when separating the laminate into each layer, it is preferably 0.03 m 3 / min or more. The upper limit of the pumping speed is not particularly limited, and the standard operating speed of the device, for example, 1.4 m 3 / min is sufficient to peel the ink and separate the laminate into single layers.

[0027] The grid shape is not particularly limited. Since the grid diameter is related to the size of the laminate after crushing, the grid diameter is preferably 0.1 to 50 mm, and more preferably 1 to 20 mm considering the crushing efficiency and the size of the laminate after crushing.

[0028] Specific examples of wet crushing pumps include the KD series of Husqvarna Zenoah, the Sankatta series of Nikuni, the Disintegrator series of Furukawa Machinery Systems, the Ink Crusher series and Refiner of Aikawa Iron Works, the Scatter of Sanwa Hydrotech, and the Trigonal manufactured by Nippon Coke.

[0029] (Colloid mill) The colloid mill used in the present invention is a machine used to reduce the particle size in a dispersion system in which particles are suspended in a liquid. The colloid mill consists of a combination of a rotor and a stator, and the rotor rotates at high speed with respect to the fixed stator. It is used to reduce the particle size in the liquid by the high level of shear generated by the high-speed rotation.

[0030] The crushing section of the colloid mill consists of a frustum-shaped rotor with a tooth shape and a stator, and the rotor and the stator have a tapered shape that becomes narrower as they approach the discharge port. The laminate is subjected to repeated strong shearing, compression, and impact in a ring-shaped gap that becomes narrower as it approaches the discharge port and is crushed.

[0031] The specific colloid mill is not particularly limited as long as it is a disperser generally called a colloid mill, and examples include the colloid mill MK series of IKA, the WCM series of Iwaki, the PUC colloid mill series of Mounttech, and the Cavitron of Eurotech.

[0032] (Grinding machine) The grinding machine preferably has a mechanism for crushing solids introduced between the upper and lower sets of mortars while rotating them in the liquid by shear or friction, and it is preferable that the solids can be ground into fine powder while flowing water.

[0033] The size of the crushed material can be adjusted by adjusting the distance between the upper and lower sets of mortars, but it is usually finely ground to 500 μm or less, preferably 300 μm or less, more preferably 200 μm or less. By reducing the size of the crushed material in this way, each layer of the plastic film becomes separated into a single layer, and the storage space for the crushed material can be reduced, making inventory management easier. Also, when producing recycled plastic from the crushed material, it can be directly fed into a kneader without passing through a compressor or the like, thus simplifying the process. On the other hand, the lower limit of the size of the crushed material is preferably 10 μm or more, preferably 30 μm or more, more preferably 50 μm or more in order to facilitate recovery.

[0034] The rotation speed and the water flow speed are not particularly limited.

[0035] Examples of specific grinding machines include the Super Mass Colloider manufactured by Masayuki Sangyo Co., Ltd.

[0036] As described above, the wet crusher can be preferably used when separating and recovering a laminate in which a printed layer is provided between a plurality of films (reverse printing).

[0037] In most cases, the reverse-printed laminate is provided with a printed layer for displaying product names and the like and imparting decorativeness in addition to the adhesive. The printed layer is often printed using a gravure printing machine, a flexographic printing machine, an offset printing machine, an inkjet printing machine, etc., with organic solvent-based printing ink, aqueous or active energy ray-curable ink. In such a laminate provided with a printed layer, in order to more efficiently peel and remove the printed layer, the laminate may be crushed in a cleaning liquid containing a cleaning component and a peeling component in water. By crushing the laminate in a cleaning liquid containing a cleaning component and a peeling component in water, it is possible to simultaneously perform the peeling and removal of the printed layer provided on the laminate and the single-layer separation of the laminate. For example, gravure ink and flexo ink are the most commonly used inks for laminates including those for food packaging. However, in the wet crushing process using a cleaning liquid, the printing can also be peeled off, which is efficient. In addition, the laminate may have a metal foil or vapor deposition film such as aluminum laminated thereon. In the present invention, the metal foil or vapor deposition film can also be peeled or dissolved. As already described above, by crushing in the presence of a liquid, each layer constituting the laminate may be peeled into single layers, or a part of the crushed laminate may be in a partially peeled state. Also, the printed layer provided on the laminate does not have to be completely removed from the laminate in Step 1, and may be partially adhered, or may not be removed from the printed layer.

[0038] When using a wet crusher in Step 1, crushing may be performed using water as a solvent, or a cleaning liquid containing a cleaning or peeling component such as an inorganic base or a surfactant, or other components in water. As the cleaning liquid, one obtained by appropriately combining one or more of the following components in water can be used.

[0039] (Inorganic base) As the aqueous cleaning liquid that can be used in Step 1, one containing an inorganic base in water can be used. Specific examples of the inorganic base include sodium hydroxide and potassium hydroxide. These inorganic bases are contained at a concentration of 0.1 to 10% by weight, preferably 0.1% to 5% by weight, based on the total amount of the aqueous cleaning liquid. Also, the pH is preferably 10 or more.

[0040] (Surfactant) As the aqueous cleaning liquid that can be used in Step 1, one containing a surfactant in water can be used. The surfactant is not particularly limited, and known surfactants can be used. For example, anionic surfactants, nonionic surfactants, amphoteric surfactants, cationic surfactants, etc. can be mentioned.

[0041] Generally, examples of nonionic surfactants include polyoxyalkylene alkyl ethers, polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenyl ethers, polyoxyethylene fatty acid esters, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene sorbitol fatty acid esters, glycerin fatty acid esters, polyoxyethylene glycerin fatty acid esters, polyglycerin fatty acid esters, sucrose fatty acid esters, polyoxyethylene alkyl amines, polyoxyethylene fatty acid amides, fatty acid alkanolamides, alkyl alkanolamides, acetylene glycols, oxyethylene adducts of acetylene glycols, polyethylene glycol polypropylene glycol block copolymers, etc. Among these, polyoxyethylene nonyl phenyl ether, polyoxyethylene octyl phenyl ether, polyoxyethylene dodecyl phenyl ether, polyoxyethylene alkyl ether, polyoxyethylene fatty acid ester, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, fatty acid alkanolamide, acetylene glycol, oxyethylene adduct of acetylene glycol, polyethylene glycol polypropylene glycol block copolymer can be mentioned.

[0042] In the present invention, it is preferable that the aqueous cleaning solution contains 60% by weight or more of water and at least one nonionic surfactant selected from polyoxyalkylene alkyl ethers, polyoxyethylene alkyl ethers and / or polyoxyethylene alkyl phenyl ethers in an amount of 0.01% to 5% by weight.

[0043] Preferably, it is an aqueous cleaning solution containing 60% by weight or more of water and 0.01% to 5% by weight of a polyoxyalkylene alkyl ether surfactant containing at least one compound represented by the general formula (1).

[0044] R 1 -O-[CH 2 -CH(X 1 )-O]n 1 -H (1) In the general formula (1), R 1 represents a linear or branched alkyl group, alkenyl group or octylphenol group, n 1 represents the average number of added moles, and X 1 represents hydrogen or a short-chain alkyl group.

[0045] More preferably, among the general formula (1), R 1 is preferably a linear or branched alkyl group or alkenyl group having 10 or more carbon atoms. The larger the number of carbon atoms exceeds 10, the better the ink stripping property, which is preferable. Specific examples of the number of carbon atoms include a decyl group having 10 carbon atoms, a lauryl group having 12 carbon atoms, a tridecyl group having 13 carbon atoms, a myristyl group having 14 carbon atoms, a cetyl group having 16 carbon atoms, an oleyl group having 18 carbon atoms, and a stearyl group.

[0046] As specific products, among the Neugen series, DSK NL-Dash series, DKS-NL series manufactured by Daiichi Kogyo Seiyaku Co., Ltd., the Nonion series manufactured by NOF Corporation, the Emulgen series manufactured by Kao Corporation, the Leox series, Leocol series, and Lionol series manufactured by Lion Corporation, etc., among the nonionic surfactants represented by the general formula (1), R1 If the number of carbon atoms shown is 10 or more, it is applicable, but it is not limited thereto.

[0047] The HLB value of the polyoxyalkylene alkyl ether surfactant represented by the general formula (1) is not particularly limited. However, when the purpose is to recover the printing layer or the adhesive layer as a film, it is preferably less than 12.5. When the purpose is to recover it in powder form, it is preferably 12.5 or more. Here, the HLB value refers to a value representing the degree of affinity of the surfactant for water and oil (organic compounds insoluble in water), and is defined by the Griffin method (HLB value = 20 × sum of the formula weights of the hydrophilic part / molecular weight).

[0048] Among the nonionic surfactants represented by the general formula (1), R 1Specific surfactants with 10 or more carbon atoms and an HLB value of less than 12.5 shown by [the company name] include, for Daiichi Kogyo Seiyaku Co., Ltd., Neugen XL-41, Neugen LF-40X, Neugen TDS-30, Neugen TDS-50, Neugen TDS-70, Neugen TDX-50, Neugen SD-30, Neugen SD-60, DKS NL-15, DKS NL-30, DKS NL-40, DKS NL-50, DKS NL-60, DKS NL-70, Neugen ET-83, Neugen ET-102, DSK Dash400, DSK Dash403, DSK Dash404, DSK Dash408, Neugen LP-55, Neugen LP-70, Neugen ET-65, Neugen ET-95, Neugen ET-115, Neugen ET-69, Neugen ET-89, Neugen ET-109, Neugen ET-129, Neugen ET-149; for NOF Corporation, Nonion K-204, Persoft NK-60, Nonion P-208, Nonion P-210, Nonion E-202, Nonion E-202S, Nonion E-205, Nonion E-205S, Nonion S-202, Nonion S-207, Nonion EH-204, Nonion ID-203, Nonion HT-505, Nonion HT-507, Nonion HT-510, Nonion HT-512; for Kao Corporation, Emulgen 102KG, Emulgen 103, Emulgen 104P, Emulgen 105, Emulgen 106, Emulgen 108, Emulgen 210P, Emulgen 404, Emulgen 408, Emulgen 409PV, Emulgen 705, Emulgen 707; for Lion Corporation, Leox CL-30, Leox CL-40, Leox CL-50, Leox CL-60, Leocol NL-30C, Leocol TD-50, Leocol TD-70, Leocol SC-50, Leocol SC-70, etc. can be exemplified, but are not limited thereto.

[0049] Among the nonionic surfactants represented by the general formula (1), specific surfactants in which R1 represents a linear or branched alkyl group or alkenyl group having 10 or more carbon atoms and the HLB value is 12.5 or more include, for Daiichi Kogyo Seiyaku Co., Ltd., Neugen XL-61, Neugen XL-6190, Neugen XL-70, Neugen XL-80, Neugen XL-100, Neugen XL-140, Neugen XL-160, XL-400D, Neugen XL-1000, Neugen LF-60X, Neugen LF-80X, Neugen LF-100X, Neugen TDS-80, Neugen TDS-100, Neugen TDS-120, Neugen TDS-200D, Neugen TDS-500F, Neugen TDX-80, Neugen TDX-80D, Neugen TDX-100D, Neugen TDX-120D, Neugen SD-70, Neugen SD-80, Neugen SD-110, Neugen SD-150, DKS NL-80, DKS NL-90, DKS NL-100, DKS NL-110, DKS NL-180, DKS NL-250, DKS NL-450F, DKS NL-600F, Neugen ET-160, Neugen ET-170, Neugen ET-190, DSK Dash410, Neugen LP-80, Neugen LP-100, Neugen LP-180, Neugen ET-135, Neugen ET-165, Neugen ET-159, Neugen ET-189; for NOF Corporation, Nonion K-220, Nonion K-230, Nonion K-2100W, Persoft NH-90C, Persoft NK-100, Persoft NK-100C, Nonion P-210, Nonion P-213, Nonion E-212, Nonion E-215, Nonion E-230, Nonion S-215, Nonion S-220, Nonion B-250, Nonion ID-206, Nonion ID-209, Dispanol TOC, Nonion HT-515, Nonion HT-518; for Kao Corporation, Emulgen 109P, Emulgen 120, Emulgen 123P, Emulgen 130K, Emulgen 147, Emulgen 150, Emulgen 220, Emulgen 320P, Emulgen 350, Emulgen 420, Emulgen 430, Emulgen 709, Emulgen 1108, Emulgen 1118S-70, Emulgen 1135S-70, Emulgen 1150S-60, Emulgen 4085, Emulgen 2020G-HA,Examples of Emulgen 2025G, manufactured by Lion Corporation, include, but are not limited to, Leox CL-90, Leox CL-230, Leocol TD-90, Leocol TD-90D, Leocol TDA-90-25, Leocol TDN-90-80, Leocol TD-120, Leocol TD-200, Leocol TDA-400-75, Leocol SC-80, Leocol SC-90, Leocol SC-120, Leocol SC-150, Leocol SC-200, Leocol SC-300, and Leocol SC-400.

[0050] When R in the general formula (1) 1 is an octylphenol group, octylphenol ethoxylate is preferred.

[0051] Specific products include, but are not limited to, the TRITON (registered trademark) series of Dow Chemical Company, the Igepal CA series of Rhodia, the Nonidet P series of Shell Chemicals, and the Nikkol OP series of Nikko Chemicals.

[0052] Specifically, as the amphoteric surfactant, a betaine-type amphoteric surfactant is preferred, and more preferably, it contains an amphoteric surfactant having an alkyl carboxybetaine skeleton or an alkylamidocarboxybetaine skeleton containing at least one compound represented by the general formula (2a).

[0053] R1-R2-N + (CH 3 ) 2 CH 2 COO - (2a) (In the general formula (2a), R1 represents hydrogen or C(=O)R3-NH- (where R3 represents a linear or branched alkyl group or alkenyl group), and R2 represents an alkylene group or alkenylene group.) In the general formula (2a), R1 preferably represents a hydrogen atom. The compound represented by the general formula (2a) is preferably an amphoteric surfactant having an alkyl carboxy betaine skeleton represented by the general formula (2a-1).

[0054] C n H 2n+1 N + (CH 3 ) 2 CH 2 COO - (2a-1) (In the general formula (2a-1), n represents the average number of added moles.) In the general formula (2a-1), n is preferably 8 or more, preferably 10 or more, and preferably 11 or more.

[0055] Specific products corresponding to the general formula (2a) include, among others, Nisshin Anon BDF (registered trademark)-R, Nisshin Anon BDF (registered trademark)-SF, Nisshin Anon BDC-SF, Nisshin Anon BDL-SF manufactured by Nippon Oil Co., Ltd.; Amorgen CB-H, Amorgen HB-C manufactured by Daiichi Kogyo Seiyaku Co., Ltd.; Recabion B-200, Recabion B-300 manufactured by Shin Nippon Rika Co., Ltd.; Obazoline CAB-30, Obazoline ISAB manufactured by Toho Chemical Industry Co., Ltd. Specific products corresponding to the general formula (1a-1) include, among others, Amorgen S, Amorgen S-H, Amorgen K manufactured by Daiichi Kogyo Seiyaku Co., Ltd.; Anhitole 20BS, Anhitole 24B, Anhitole 86B manufactured by Kao Corporation; Nisshin Anon BF, Nisshin Anon BL, Nisshin Anon BL-SF manufactured by Nippon Oil Co., Ltd.; Recabion A-100, Recabion A-200, Recabion A-700 manufactured by Shin Nippon Rika Co., Ltd.; Obazoline LB, Obazoline LB-SF manufactured by Toho Chemical Co., Ltd., but are not limited thereto.

[0056] In addition, the betaine-type amphoteric surfactant may have an imidazolinium betaine skeleton. Specific products corresponding thereto include, among others, Nisshin Anon GLM-R, Nisshin Anon GLM-R-LV manufactured by Nippon Oil Co., Ltd.; Anhitole 20Y-B manufactured by Kao Corporation, but are not limited thereto.

[0057] As the amphoteric surfactant, a surfactant represented by the following general formula (2b) may also be used.

[0058] R4-(NHC 2 H 4 ) nb -N(R5) 2 (2b) (In the general formula (2b), R4 represents a linear or branched alkyl group or alkenyl group, nb represents an integer of 0 to 5, and R5 represents hydrogen, -CH 2 COONa or -CH 2 COOH. However, the two R5s may be the same or different, and at least one R5 represents -CH 2 COONa.) In the general formula (2b), R4 preferably represents a linear alkyl group, and the number of carbon atoms of R4 is preferably 8 or more, preferably 10 or more, and preferably 12 or more.

[0059] Specific products corresponding to the general formula (2b) include, but are not limited to, Nissan Anon LG-R and Nissan Anon LA manufactured by NOF Corporation.

[0060] As the amphoteric surfactant, an amine oxide type surfactant represented by the following general formula (2c) may also be used.

[0061] R6-N + (CH 3 ) 2 O - (2c) (In the general formula (2c), R6 represents a linear or branched alkyl group or alkenyl group.) In the general formula (2c), R6 preferably represents a linear alkyl group as in R4 in the general formula (2b), and the number of carbon atoms of R4 is preferably 8 or more, preferably 10 or more, and preferably 12 or more.

[0062] Specific products corresponding to the general formula (2c) include, but are not limited to, Amogen AOL manufactured by Daiichi Sankyo Co., Ltd. and Unichol 20N manufactured by Kao Corporation.

[0063] Specifically, as the cationic surfactant, a cationic surfactant having a quaternary ammonium skeleton is preferable, and more preferably, a cationic surfactant having a quaternary ammonium skeleton containing at least one compound represented by the general formula (3a).

[0064] R1-N + (R2R3)-R4 (3a) (In the general formula (3a), R1 represents a linear or branched alkyl group or a linear or branched alkenyl group, and -CH in the alkyl group or alkenyl group 2 - may be substituted with -C(=O)-, -NH- or -C(=O)-NH-. R2 and R3 represent a hydrogen atom, a linear or branched alkyl group or a linear or branched alkenyl group, and R4 represents a hydrogen atom, a linear or branched alkyl group, a linear or branched alkenyl group or a phenyl group, and the terminal -CH in the alkyl group or alkenyl group 3 - may be substituted with a carboxy group or a phenyl group.) In the general formula (3a), R1 is preferably a long-chain alkyl group or alkenyl group in order to further enhance the peelability of the ink, specifically preferably an alkyl group or alkenyl group having 8 to 30 carbon atoms, preferably an alkyl group having 10 to 25 carbon atoms, and preferably an alkyl group or alkenyl group having 12 to 22 carbon atoms. The alkyl group or alkenyl group may be linear or branched, but is preferably linear, and more preferably a linear alkyl group.

[0065] R1 may have at least one or more -CH in the alkyl group or alkenyl group 2 - substituted with -C(=O)-, -NH- or -C(=O)-NH-. Among them, at least one or more -CH in the alkyl group or alkenyl group 2- is preferably substituted with -C(=O)-NH- or -NH-C(=O), and one -CH in the alkyl group 2 - is preferably substituted with -C(=O)-NH- or -NH-C(=O), and more preferably has an amidopropyl skeleton in R1.

[0066] R2 and R3 preferably represent a linear or branched alkyl group or a linear or branched alkenyl group, and preferably represent a linear or branched alkyl group. Among them, it preferably represents a linear alkyl group having 1 to 3 carbon atoms, and more preferably represents a methyl group.

[0067] R4 preferably represents a linear or branched alkyl group, a linear or branched alkenyl group or a phenyl group, and more preferably represents a linear or branched alkyl group. Also, the terminal -CH in the alkyl group or alkenyl group 3 is preferably substituted with a carboxy group or a phenyl group.

[0068] R4 preferably has 1 to 8 carbon atoms, preferably 1 to 5 carbon atoms, preferably 1 to 3 carbon atoms, and more preferably represents 1 or 2.

[0069] When R4 represents a methyl group, R2 and R3 also preferably represent a methyl group, and the general formula (3a) preferably represents an alkyltrimethylammonium skeleton.

[0070] Also, when R4 represents an ethyl group, the terminal -CH in the ethyl group 3 is preferably substituted with a carboxy group or a phenyl group. That is, R4 preferably represents -CH 2 -(C(=O)OH or preferably represents a benzyl group. The compound represented by the general formula (3a) is preferably a cationic surfactant having a quaternary ammonium skeleton represented by the general formula (3a-1).

[0071] C n H2n+1 N + (CH 3 ) 2 R4 (3a-1) (In general formula (3a-1), n represents the average number of added moles, and R4 has the same meaning as R4 in general formula (3a) described in claim 3.) In general formula (3a-1), the number of carbon atoms indicated by n is preferably 8 or more. The more the number of carbon atoms exceeds 8, the better the ink releasability, which is preferable. Specific examples of the number of carbon atoms include an octyl group having 8 carbon atoms, a nonyl group having 9 carbon atoms, a decyl group having 10 carbon atoms, an undecyl group having 11 carbon atoms, a lauryl group having 12 carbon atoms, a tridecyl group having 13 carbon atoms, a myristyl group having 14 carbon atoms, a pentadecyl group having 15 carbon atoms, a cetyl group having 16 carbon atoms, an oleyl group having 18 carbon atoms, and a stearyl group.

[0072] Preferred groups for R4 are the same as those in general formula (3a). These cationic surfactants with a quaternary ammonium skeleton are preferably in the form of a quaternary ammonium skeleton salt formed with a halogen, preferably forming a salt with Cl - and more preferably forming a salt with Br - and still more preferably forming a salt with I - and preferably forming a salt with it. The quaternary ammonium skeleton salt formed with a halogen is considered to improve the ink releasability because it promotes the hydrolysis of the ink film by the nucleophilic action of the halogen.

[0073] Among them, compounds of the alkyltrimethylammonium chloride type, dialkyldimethylammonium chloride type, and alkylbenzalkonium chloride type are preferable.

[0074] Specific products corresponding to the general formula (3a) or (3a-1) include, among those manufactured by Nippon Oil Co., Ltd., Nissan Cation MA, Nissan Cation SA, Nissan Cation BB, Nissan Cation FB, Nissan Cation PB-300, Nissan Cation ABT2-500, Nissan Cation AB, Nissan Cation AB-600, Nissan Cation VB-M Flakes, Nissan Cation VB-F, Nissan Cation 2-DB-500E, Nissan Cation 2-DB-800E, Nissan Cation 2ABT, Nissan Cation 2-OLR, Nissan Cation F 2 -50R, and Nissan Cation M 2 -100R. Among those manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., Cationogen TML, Cationogen TMP, Cationogen TMS, Cationogen DDM-PG, Cationogen BC-50, and Cationogen TBB can be mentioned. Among those manufactured by Kao Corporation, Cotamine 24P, Cotamine 86P Conc., Cotamine 60W, Cotamine 86W, Sanizol C, and Sanizol B-50 can be mentioned. Among those manufactured by Lion Corporation, Lipgard C-50, Lipgard T-28, Lipgard T-30, Lipgard T-50, Lipgard T-800, Lipgard 16-29, Lipgard 16-50E, Lipgard 18-63, Lipgard 22-80, Lipgard CB-50, Lipgard 210-80E, Lipgard 2C-75, Lipgard 2HP-75, Lipgard 2HP Flakes, Lipgard 2HT-75, Lipgard 2HT Flakes, Lipgard 20-75l, Lipgard 41-50, TMAC-50, TPAH-40, TBAB-50A, TBAB-100A, TBAH-40, Lipgard PH-100, BTMAC-50, BTMAC-100A, BTEAC-50, BTEAC-100A, BTBAC-50A, etc. can be mentioned, but the invention is not limited thereto.

[0075] In addition, the cationic surfactant preferably contains at least one compound represented by a primary to secondary alkanolamine skeleton, and preferably contains at least one compound represented by a monoalkanolamine skeleton.

[0076] As the primary monoalkanolamine, it is preferably a lower alkanol having 1 to 4 carbon atoms. Specifically, monoethanolamine, 2-aminoisobutanol, etc. can be mentioned. As the secondary monoalkanolamine, N-methylethanolamine, 2-ethylaminoethanol, isopropanolamine, etc. can be mentioned, but substances other than those exemplified can also be used as appropriate. These monoalkanolamine-based compounds can be used alone or in appropriate combinations of two or more, and can also be used after being mixed with water. These cationic surfactants having a monoalkanolamine skeleton are preferably in the form of monoalkanolamine salts that form salts with halogens, and preferably form salts with Cl - It is preferable to form a salt.

[0077] These surfactants can be used alone or in combination of two or more. The addition amount is preferably in the range of 5% by weight or less, and preferably 2% by mass or less, based on the total amount of the aqueous cleaning solution. The lower limit value of the surfactant is not particularly limited and may be 0% by mass, but when the surfactant is contained, it is preferably 0.1% by mass or more.

[0078] (Water-insoluble alcohol) As the cleaning solution that can be used in Step 1, one containing a water-insoluble primary alcohol in water can be used. The water-insoluble primary alcohol is preferably contained in an amount of 20% by weight or less based on water.

[0079] Examples of the water-insoluble primary alcohol include butan-1-ol, pentan-1-ol, hexan-1-ol, heptan-1-ol, octan-1-ol, nonan-1-ol, decan-1-ol, undecan-1-ol, dodecan-1-ol, tridecan-1-ol, tetradecan-1-ol, pentadecan-1-ol, hexadecan-1-ol, heptadecan-1-ol, octadecan-1-ol, nonadecan-1-ol, icosan-1-ol, heneicosan-1-ol, docosan-1-ol, tricosan-1-ol, tetracosan-1-ol, pentacosan-1-ol, hexacosan-1-ol, heptacosan-1-ol, octacosan-1-ol, nonacosan-1-ol, triacontan-1-ol, polycosanol, 2-methylpropan-1-ol, and benzyl alcohol. Among them, butan-1-ol and benzyl alcohol are preferred.

[0080] (Water-soluble alcohol) As the cleaning liquid that can be used in Step 1, a liquid containing a water-soluble primary alcohol in water can be used. Examples of the water-soluble primary alcohol include methanol, ethanol, and propan-1-ol, and a mixture of them arbitrarily mixed as industrial alcohol can also be used. The water-soluble primary alcohol is preferably contained in an amount of 20% by weight or more based on water.

[0081] (Water-insoluble glycol ether-based organic solvent) As the cleaning liquid that can be used in Step 1, a liquid containing a water-insoluble glycol ether-based organic solvent in water can be used. The water-insoluble glycol ether-based organic solvent is preferably an aqueous cleaning liquid contained in an amount of 20% by weight or less based on water.

[0082] Examples of the water-insoluble glycol ether-based organic solvent include aromatic glycol ethers.

[0083] (Aromatic glycol ether solvent) As the cleaning liquid that can be used in Step 1, one containing an aromatic glycol ether solvent in water can be used. Examples of the aromatic glycol ether solvent include, for example, as examples of aromatic glycol ethers, ethylene glycol monophenyl ether (phenoxyethanol), ethylene glycol monobenzyl ether, ethylene glycol dibenzyl ether, diethylene glycol monophenyl ether, diethylene glycol diphenyl ether, propylene glycol monophenyl ether, and the like. Examples of ester-based glycol ethers include ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol mono-n-butyl ether acetate, diethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate, dipropylene glycol monomethyl ether acetate, and the like. Among them, ethylene glycol monophenyl ether (phenoxyethanol) is more preferable.

[0084] (Water-soluble glycol ether-based organic solvent) As the cleaning liquid that can be used in Step 1, one containing a water-soluble glycol ether-based organic solvent in water can be used. The water-soluble glycol ether-based organic solvent is preferably an aqueous cleaning liquid containing 20% by weight or more with respect to water.

[0085] Examples of the water-soluble glycol ether-based organic solvent include, for example, alkylene glycol alkyl ethers.

[0086] (Water-soluble alkylene glycol alkyl ether solvent) R 1 -O-[CH 2 -CH(X)-O]n 1 -R 2 (4) (In General Formula (4), R 1 is an alkyl group having 1 or more carbon atoms, R 2 is an alkyl group having 1 or more carbon atoms or hydrogen, and n 1n represents an integer of 1 to 3, and X represents hydrogen or a methyl group.) Among the alkylene glycol alkyl ethers represented by the general formula (4), more preferably, they are water-soluble alkylene glycol alkyl ethers.

[0087] Examples of the alkylene glycol alkyl ether represented by the general formula (4) include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dipropyl ether, ethylene glycol methyl ethyl ether, ethylene glycol methyl propyl ether, ethylene glycol ethyl propyl ether, ethylene glycol monobutyl ether, ethylene glycol - tert - butyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dipropyl ether, diethylene glycol methyl ethyl ether, diethylene glycol methyl propyl ether, diethylene glycol ethyl propyl ether, triethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, propylene glycol dimethyl ether, propylene glycol diethyl ether, etc. These alkylene glycol alkyl ethers can be used alone or in combination of two or more as appropriate, and can also be used after being mixed with water. There is no particular problem as long as the content of the alkylene glycol alkyl ether is 20% by weight or more, but when water is the medium, 30% by weight or more is preferable, and 40% by weight or more is most preferable. On the other hand, the upper limit may be 100% by weight, but from the viewpoints of environmental impact and safety, it is preferable to use water as the medium.

[0088] Among the water-soluble alkylene glycol alkyl ethers represented by the general formula (4), more preferred are the alkylene glycol monoalkyl ethers represented by the general formula (5).

[0089] R 2 -O-[CH 2 -CH(X)-O]n 2 -H (5) (In the general formula (5), R 2 represents an alkyl group having 1 or more carbon atoms, n 2 represents an integer of 1 to 3, and X represents hydrogen or a methyl group.) Examples of the water-soluble alkylene glycol alkyl ether represented by the general formula (5) include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monobutyl ether, ethylene glycol - tert-butyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, diethylene glycol monobutyl ether, triethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, etc.

[0090] Furthermore, in the aqueous cleaning liquid containing the water-soluble alkylene glycol alkyl ether represented by the general formula (5), in terms of maintaining the peelability even in a composition in which the content ratio of water is greatly exceeding 50% by weight, R 2 is an alkyl group having 3 or more carbon atoms, n 2 is 1 to 3, and X 2 is preferably hydrogen or a methyl group.

[0091] Specifically, examples thereof include ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, ethylene glycol - tert - butyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, triethylene glycol monobutyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, etc. These alkylene glycol alkyl ethers can be used alone or in appropriate combinations of two or more, and can also be used after being mixed with water.

[0092] Furthermore, among these, diethylene glycol monobutyl ether, ethylene glycol - tert - butyl ether, and propylene glycol monopropyl ether are particularly preferred from the viewpoints of environmental characteristics, flammability, and defoaming properties.

[0093] (Water - soluble monoalkanolamine - based organic solvent) As the cleaning liquid that can be used in Step 1, one containing a water - soluble alkanolamine - based organic solvent in water can be used. The water - soluble alkanolamine - based organic solvent is preferably an aqueous cleaning liquid containing 20% by weight or more with respect to water. Primary to secondary monoalkanolamines having a boiling point of 150 - 200°C can be contained in an amount of 10% to 50% by weight based on the total amount of the cleaning liquid.

[0094] Examples of the primary monoalkanolamine include monoethanolamine, 2 - amino - isobutanol, isopropanolamine, etc. Examples of the secondary monoalkanolamine include N - methylethanolamine, 2 - ethylaminoethanol, dimethylaminoethanol, etc. However, in the case of primary to secondary monoalkanolamines, substances other than the exemplified ones can also be appropriately used as long as the boiling point is within 150 - 200°C. Also, these monoalkanolamine - based compounds can be used alone or in appropriate combinations of two or more, and can also be used after being mixed with water.

[0095] (Defoaming agent) The water used in Step 1 may contain an antifoaming agent. In Step 1, a large amount of foam may be generated during the stirring or crushing process, and if the foam remains, it may overflow during the laminate recovery process. Also, in the laminate crushing process, if a large amount of foam is entrained in the cleaning liquid, the laminate may not be crushed to the desired size.

[0096] As compounds generally used as antifoaming agents, water-soluble organic solvents or nonionic surfactants with a low HLB value in the range of 1 to 3 are used. However, silicone-based compounds are particularly preferred compounds in terms of high defoaming ability. Among them, emulsion-type or self-emulsifying silicone compounds are preferred.

[0097] Specific antifoaming agents include, as self-emulsifying types, X-50-1176, KS-530, and KS-537 manufactured by Shin-Etsu Chemical Co., Ltd. Examples of emulsion types include KM-7750D, KM-7752, KM-98 manufactured by Shin-Etsu Chemical Co., Ltd., FS Antifoam 025, FS Antifoam 80, FS Antifoam 92, FS Antifoam 93, DKQ1-1183, DKQ1-1247 manufactured by Nagase ChemteX Corporation, etc., but are not limited thereto.

[0098] The antifoaming agent may be used alone or in combination of two or more. It is preferably in the range of 0.01 to 5% by weight, more preferably in the range of 0.02 to 4% by weight, and even more preferably in the range of 0.03 to 3% by weight in the cleaning liquid usable in Step 1.

[0099] (Liquid temperature) The liquid temperature of the water or cleaning liquid used in Step 1 is not particularly limited as long as the liquid state can be maintained, but usually it is preferably carried out at a liquid temperature of 15 to 90°C. When using an aqueous cleaning liquid with a surfactant or the like added to water, it is preferable to adjust the liquid temperature according to the type of surfactant. The optimal temperature with excellent cleaning effect varies depending on the type of surfactant. For example, 40°C or higher is preferable, 65°C or higher is preferable, and 85°C or higher is preferable. On the one hand, when it is desired to enhance the crushability of the laminate, that is, to crush the laminate into finer pieces, it is preferable that the liquid temperature is not too high. Thus, a temperature of 40°C or lower is preferred, a temperature of 30°C or lower is more preferred, and a temperature of 20°C or lower is most preferred. Since the smaller the size of the laminate after crushing, the larger the cross-sectional area, in Step 2, each layer constituting the laminate can easily swell into a single layer.

[0100] <Regarding Step 2> The method for separating and recovering the laminate of the present invention includes Step 2 of immersing the crushed laminate in Step 1 in a cleaning liquid. In Step 2, each layer, printing layer, and primer layer constituting the laminate can easily swell.

[0101] (Immersion time) In Step 2, the immersion time is preferably a time sufficient for the crushed laminate to swell sufficiently. Specifically, it is preferably 30 minutes or longer. More specifically, it is in the range of 30 minutes to 48 hours. If the lower limit is less than 30 minutes, it becomes difficult to swell sufficiently in Step 2. On the other hand, if the upper limit exceeds 48 hours, it takes too much time for the separation and recovery of the present invention.

[0102] Also, the immersion time can be appropriately adjusted by combining the liquid temperature and stirring described below. The higher the liquid temperature, the shorter the immersion time required. When constructing a practical recycling system, it is preferable to set the upper limit of the immersion time to about 4 hours while heating the liquid temperature. For example, when immersing at room temperature, sufficient swelling can be achieved by immersing for 24 hours or longer. When the liquid temperature is 40°C, sufficient swelling can be achieved by immersing for 16 hours. When the liquid temperature is 75°C, sufficient swelling can be achieved by immersing for 2 hours.

[0103] (Temperature) In Step 2, the liquid temperature of the cleaning liquid is not particularly limited as long as the liquid state can be maintained. If the liquid temperature is at room temperature, heating is not required, so CO 2It is preferable as it can contribute to emission reduction. On the other hand, when prioritizing efficiency as a practical recycling system, a method of shortening the immersion time while heating the liquid temperature is also preferable. That is, usually, it is preferable to carry out at a liquid temperature of 15 to 90°C. When using an aqueous cleaning liquid with a surfactant or the like added to water, it is preferable to adjust the liquid temperature according to the type of surfactant. The optimal temperature with excellent cleaning effect varies depending on the type of surfactant, but 40°C or higher is preferable, 50°C or higher is preferable, and 60°C or higher is preferable. The upper limit of the liquid temperature is not particularly limited as long as the liquid state can be maintained, but usually 90°C or lower is preferable.

[0104] (Stirring) In step 2, stirring is not essential and may be optional, but it is more efficient to swell when stirred. It is preferable to keep the stirring speed at a level where foaming or the like is unlikely to occur even without adding an antifoaming agent.

[0105] The equipment and method for stirring when stirring are not particularly limited, and known methods can be used. Specifically, there are a device equipped with a motor with stirring blades capable of stirring the cleaning liquid in a container, a device equipped with a device for generating ultrasonic waves, a device capable of shaking the entire container, a wet crusher, etc. The wet crusher can be the same as the crusher described in step 1.

[0106] (Cleaning liquid) The cleaning liquid used in step 2 can also be used as it is the cleaning liquid used when using the wet crusher in step 1. Specifically, it is preferable to use a cleaning liquid containing water, the inorganic base described in step 1, and the surfactant described in step 1.

[0107] Also, the cleaning liquid used in Step 2 may preferably contain an appropriate amount of an organic solvent. As the organic solvent, for example, it is preferable to contain one or more water-soluble alcohols and water-soluble solvents having a flash point of 21°C or higher. By using a water-soluble solvent in the cleaning liquid, hydroxide ions generated from the inorganic base contained in the cleaning liquid are less likely to be hydrated, so the nucleophilicity of the hydroxide ions increases, and also, since the reaction of peeling the printing layer can proceed in a hydrophobic field environment, it is effective for peeling the peeling primer layer and the ink film.

[0108] As the water-soluble solvent having a flash point of 21°C or higher, a water-soluble solvent among the organic solvents corresponding to Class II petroleum and Class III petroleum specified in the Fire Service Act is preferable. For example, diethylene glycol butyl ether, propylene glycol propyl ether, and 3-methoxy-3-methyl-1-butanol are preferable.

[0109] Also, examples of the water-soluble alcohols include alcohols specified in the Fire Service Act. Specifically, these include methanol, ethanol, 1-propyl alcohol, 2-propyl alcohol, etc., and these may be used alone or in combination.

[0110] Also, as the organic solvent, it may preferably contain the water-insoluble alcohols and water-insoluble glycol ether-based organic solvents described in Step 1. Among them, butan-1-ol, benzyl alcohol, and ethylene glycol monophenyl ether (phenoxyethanol) are particularly preferable.

[0111] In Step 2, by sufficiently swelling the laminate crushed in Step 1, the laminate can be easily and completely peeled into a single layer even with only water in Step 3. In particular, when the laminate has a printing layer, it is difficult to make the laminate colorless depending on the type of ink and the composition of the plastic film. However, in the present invention, by performing Step 1 and Step 2, a base layer for peeling at least a part of each layer of the laminate or making it easier to peel is created, and in Step 3 described below, the laminate is separated into a single layer and the printing layer is peeled off. Therefore, the printing layer can be easily peeled off regardless of the type of ink and the composition of the laminate.

[0112] In particular, from the viewpoint of the peelability of the printing layer, the cleaning liquid used in Step 2 preferably contains a large amount of a water-soluble solvent in the cleaning liquid. Specifically, the water-soluble solvent is preferably 30% by mass or more, preferably 40% by mass or more, preferably 50% by mass or more, preferably 60% by mass or more, preferably 70% by mass or more, preferably 80% by mass or more, preferably 90% by mass or more, and preferably 95% by mass or more.

[0113] In addition, the cleaning liquid used in Step 2 preferably contains an inorganic base. Specific examples of the inorganic base include sodium hydroxide and potassium hydroxide. These inorganic bases are preferably contained at a concentration of 0.1 to 10% by weight based on the total amount of the ink cleaning liquid, and a concentration of 0.1% by weight to 5% by weight is more preferable. Also, the pH is preferably 10 or more, preferably 11 or more, and more preferably 12 or more. Since sodium hydroxide is hardly soluble in an organic solvent, it is preferable to use a cationic surfactant in combination when using sodium hydroxide. Specifically, a cleaning liquid containing sodium hydroxide, a cationic surfactant, a water-insoluble aromatic glycol ether solvent, and a water-soluble alcohol or a water-soluble alkanolamine solvent can be mentioned. On the other hand, when using potassium hydroxide, since it is easily soluble in an organic solvent, it is not necessary to use a cationic surfactant in combination. Specifically, for example, a cleaning liquid containing potassium hydroxide and a water-soluble alcohol or an aromatic glycol ether solvent can be mentioned.

[0114] In addition, the cleaning liquid used particularly in Step 2 may contain water. By containing water in the cleaning liquid of Step 2, the working stability and environmental stability in Step 2 can be improved.

[0115] In addition, the cleaning liquid used particularly in Step 2 may contain a surfactant. The surfactant is not particularly limited, and known surfactants can be used. For example, anionic surfactants, nonionic surfactants, amphoteric surfactants, cationic surfactants, etc. can be mentioned. Specific types of these surfactants can be the same as those described as surfactants that can be contained in water in Step 1. In the cleaning liquid of Step 2, the surfactant can be used alone or in combination of two or more. The addition amount is preferably in the range of 5% by weight or less, and preferably 2% by mass or less, based on the total amount of the cleaning liquid. The lower limit value of the surfactant is not particularly limited and may be 0% by mass, but when the surfactant is contained, it is preferably 0.01% by mass or more.

[0116] <Regarding Step 3> The method for separating and recovering the laminate of the present invention has Step 3 of separating the laminate by stirring the crushed and swollen laminate in the presence of a liquid after going through the above-mentioned Step 1 and Step 2.

[0117] (Stirring) In Step 3, the equipment and method for stirring, when stirring is required, are not particularly limited, and known methods can be used. Specifically, examples include an apparatus equipped with a motor with stirring blades capable of stirring the cleaning liquid in a container, an apparatus equipped with an apparatus for generating ultrasonic waves, an apparatus capable of shaking the entire container, and a wet crusher. The wet crusher can be the same as the crusher described in Step 1, and any crusher can be used as long as it can crush the laminate crushed in Step 1 while stirring in the presence of a liquid. By crushing the laminate while stirring it in the presence of a liquid in Step 3, the peeling of the adhesive layer and the release primer layer provided between the resin base material A and the resin base material B can be promoted. Further, when there is a printing layer between the resin base material A and the resin base material B, the removal of the printing layer, the adhesive layer, and the release primer layer can be promoted.

[0118] Step 3 preferably includes a step in which the laminate crushed in Step 1 passes through a clearance of 30 mm or less. The clearance is more preferably 20 mm or less, and even more preferably 10 mm or less. By passing through a clearance of 10 mm or less, a high shear force can be applied to the plastic film. For example, it has the effect of rubbing off ink from a laminate in which the printing layer is provided exposed, or the effect of applying shear stress to a laminate in which the printing layer is provided between a plurality of films, and can promote the peeling of the laminate.

[0119] Since the wet crusher has a mechanism for crushing with a fixed blade and a rotating blade, the clearance can be easily controlled according to its operating conditions. The smaller the clearance, the higher the shear force that can be applied to the laminate. However, the smaller the clearance, the more likely the laminate is to become clogged, and the faster the liquid temperature of water or the cleaning liquid rises. Therefore, it is preferably 0.1 mm or more.

[0120] The clearance through which the laminate passes is specifically provided by a method of applying high shear with a clearance of a predetermined size or less. For example, controlling the size gap between the inner wall of the tank of the treatment tank that stirs the laminate and / or water and the stirring blade to be a predetermined size or less, installing a baffle plate at a distance of a predetermined size or less from the tank wall, designing the laminate and / or water to pass through a screen having holes with a diameter of a predetermined size or less, passing between two rolls with a gap of a predetermined size or less, sandwiching the laminate using a ball mill or the like and causing the media to collide with each other, providing a fixed blade outside the rotating blade like a homogenizer and controlling the gap between the rotating blade and the fixed blade to be a predetermined size or less, etc. can be designed.

[0121] The shear rate in Step 3 is preferably 2,000 s -1 or more. The higher the shear rate, the higher the effect of scraping off the ink from the laminate and the effect of applying shear stress to the laminate in which the printed layer is provided between a plurality of films, so the upper limit is not limited.

[0122] Note that the shear rate (D) referred to here is defined by the following formula. D = v / Δy v: flow velocity (m / s), calculated as v = π × R × (n / 60) π: pi R: diameter of the rotating blade (m) n: rotational speed of the rotating blade (rpm) Δy: clearance (m), here refers to the gap between the rotating blade and the fixed blade (m).

[0123] The larger the diameter of the fixed blade of the wet crusher, the higher the flow velocity. Therefore, the larger the size of the fixed blade of the wet crusher, the more preferable. The narrower the clearance, the higher the shear rate. Therefore, the narrower the clearance, the more preferable. The blade design of the fixed blade and the rotating blade preferably has a shape in which at least some of the blades are arranged in the radial direction. The blades arranged in the radial direction are preferably inclined 2 to 60° from the radial direction. More preferably, it is 5 to 45°. When a plurality of cutting tools are arranged in parallel on the rotary blade, the blade width of the rotary blade is preferably 0.5 to 5.0 mm, the groove width between the blades is preferably 0.5 to 5.0 mm, and the height of the blade is preferably 1.0 to 5.0 mm.

[0124] In step 3, the stirring Froude number (Fr) is preferably 10 or more. The higher the stirring Froude number, the higher the effect of scraping off the ink from the laminate and the effect of applying shear stress to the laminate in which the printed layer is provided between a plurality of films, so the upper limit is not limited. Note that the stirring Froude number (Fr) referred to here is defined by the following formula. Fr ={(n / 60) 2}×R / g n: Rotation speed of the rotary blade (rpm) R: Diameter of the rotary blade (m) g: Acceleration due to gravity = 9.8 (m / s 2 )

[0125] Since step 3 is a step of peeling off an adhesive, a printed layer, etc. from the laminate swollen in the presence of a liquid, it is preferable to use a wet crusher capable of obtaining a high shearing force and / or a high frictional force. Examples of such wet crushers include the KD series of Husqvarna Zenoah, the Sankatta series of Nikuni, the Disintegrator series of Furukawa Machinery Systems, the Ink Crusher series and refiners of Aikawa Iron Works, the Scatter of Sanwa Hydrotech, the Trigonal made by Nippon Coke, the Alkali Cleaning / Washing and Deinking Equipment made by Nippon Seam, and the Shears Cutter series of Washing and Crushing Machines.

[0126] In step 3, known dispersing equipment using media such as beads and rods can be used. Examples of the disperser with media include dispersers having stirring blades such as Disper and turbine blades, paint shakers, roll mills, ball mills, vibration mills, attritors, sand mills, bead mills, etc. As the media to be used, it is preferable to use salts, glass beads, zirconia beads, etc. The spherical diameter of the beads to be used is preferably 0.5 to 35 mm, more preferably 5 to 30 mm, and even more preferably 10 mm to 25 mm. Examples of the medium material include steel, zirconia, alumina, stainless steel, glass, etc. If the medium diameter is less than 0.5 mm, it is difficult to handle, and it becomes difficult to recover the medium mixed with plastic pieces. If it exceeds 35 mm, handling becomes easy, but the processing time becomes extremely long, causing a decrease in productivity. The residence time in the disperser is preferably 0.5 to 30 minutes. The diameter of the rod to be used is preferably 35 mm or less, more preferably 24 mm, and even more preferably 19 mm or less. Examples of the rod material include steel, zirconia, alumina, stainless steel, etc. If the rod diameter is less than 12 mm, it is difficult to handle, and it becomes difficult to twist and mix in the disperser. If it exceeds 35 mm, the number of contacts with the laminate within a predetermined time decreases, and the processing time becomes extremely long, causing a decrease in productivity.

[0127] The filling rate of the beads and rods to be used is preferably 60% or less, more preferably 45% or less, and even more preferably 30% or less. If the filling rate is 80% or more, the number of contacts with the laminate increases, but the energy applied to the laminate is small, and it takes time to peel the printed layer and the adhesive layer. If the filling rate is 10% or less, the number of contacts with the laminate decreases, and the processing time becomes extremely long, causing a decrease in productivity. Examples of the disperser with the medium include the Star Mill manufactured by Ashizawa Fine Tech Co., Ltd., the MSC-MILL and SC-MILL manufactured by Mitsui Mining Co., Ltd., the Attritor MA01SC, the Apex Mill manufactured by Hiroshima Metal & Machinery Co., Ltd., the Vibration Mill manufactured by Central Chemical Machinery Co., Ltd., the Nano Glen Mill, Pico Glen Mill, Pure Glen Mill, Mega Capper Glen Mill, Cera Power Glen Mill, Dual Glen Mill, AD Mill, Twin AD Mill, Basket Mill, Twin Basket Mill, the Apex Mill and Ultra Apex Mill and Super Apex Mill manufactured by Kotobuki Industries Co., Ltd., etc.

[0128] The stirring time in Step 3 is not particularly limited as long as the laminate can be stirred. Although it varies depending on the stirring equipment and method used, it is preferably 0.5 minutes or more, more preferably 3 minutes or more, and still more preferably 5 minutes or more in order to perform sufficient stirring. On the other hand, the upper limit of the stirring time is not particularly limited, but it is preferably 60 minutes or less, and more preferably 30 minutes or less.

[0129] (Ink removability) The ink removability of the plastic crushed material after Step 3 is preferably 50% or more, more preferably 75% or more, and particularly preferably 90% or more.

[0130] The ink removability is measured as follows.

[0131] After washing and drying the plastic crushed material (plastic film pieces) after the stirring step of Step 3, the ink removability of the printed portion is determined by calculating the area through image processing of a photograph taken using an optical microscope and obtaining the ink removal rate using the following formula. Ink removal rate (%) = (1 - Area of ink adhesion after washing / Area of ink adhesion before washing) × 100

[0132] (Surface roughness) The surface roughness of the plastic crushed material (plastic film pieces) after Step 3 is preferably 0.7 μm or more. By making the surface roughness of the crushed material 0.7 μm or more using the wet crushing equipment as described above, the laminate can be separated into a single layer, and not only the printed layer provided on the surface of the laminate but also the printed layer provided between the laminates can be removed. Therefore, the recovered crushed material is suitable as a raw material for manufacturing high-quality recycled plastic. The surface roughness of the crushed material is preferably 0.7 μm or more, more preferably 0.8 μm or more, and still more preferably 0.9 μm or more. On the other hand, the upper limit is not particularly limited and can be appropriately adjusted according to the conditions of the wet crushing equipment. The surface roughness of the film is determined by measuring the surface roughness Sa of 500 μm × 600 μm using a white interference microscope manufactured by Rhombus Systems. Since Sa is a value indicating the entire in-plane area rather than a value obtained from a cross-section like Ra, the evaluation range is wider and the overall surface roughness can be evaluated.

[0133] (Size of plastic crushed material (film pieces)) The size of the plastic film pieces after Step 3 is preferably 20 mm or less, more preferably 10 mm or less, and even more preferably 5 mm or less in the length direction of the long side. Also, the size in the short side direction is preferably 20 mm or less, preferably 10 mm or less, preferably 5 mm or less, and preferably 3 mm or less. There is no particular limitation on the lower limit of the size of the crushed material, but if it is too small, the recoverability will decrease, so the length in the long side direction is preferably 1 mm or more.

[0134] (Volume ratio of film pieces after Step 1 and after Step 3) When the film volume after Step 1 is set to 1, the volume after Step 3 is preferably at least 1 or less, more preferably 0.99 or less, and even more preferably 0.8 or less. Since Step 3 is a step of cleaning the film surface, the smaller the film is compared to its original size during cleaning, the better the rubbing and washing are indicated.

[0135] (Liquid) The liquid used in Step 3 is, for example, water or a cleaning liquid. As the cleaning liquid, a cleaning liquid containing the cleaning components exemplified in Step 2 can be used, and the preferred examples of the cleaning liquid are the same as the preferred cleaning liquid examples shown in Step 2. From the viewpoint of suppressing equipment deterioration (such as corrosion), the pH of the liquid is preferably 12.0 or less, more preferably 8.0 or less, and even more preferably the liquid is water. In Step 3, the separated plastic crushed materials in a single layer are such that olefins with a low specific gravity float in water, while compositions containing a heavy specific gravity printing layer or adhesive layer sink. Immediately after Step 3, they may be partially mixed and floating, and it is preferable to proceed with specific gravity separation using a specific gravity separator manufactured by Nippon Seam Co., Ltd. etc.

[0136] (Recovery Equipment) In Step 3, the separated plastic crushed materials in a single layer can be recovered layer by layer. The equipment and methods for recovering the plastic crushed materials are not particularly limited, and for example, a filter press, a centrifuge, an automatic scraping bar screen, an inclined wire screen, a rotary drum screen, etc. can be used. The recovery equipment is preferably equipment that can separate plastic crushed materials with a short side direction of 1 μm or more using various filters including meshes and non-woven fabrics.

[0137] <Regarding Step 4> The method for separating and recovering the laminated plastic film of the present invention preferably includes Step 4 of finishing and washing the plastic crushed material film by stirring the plastic crushed material film recovered layer by layer in a rinse liquid after going through the above-mentioned Steps 1, 2, and 3.

[0138] (Stirring) In Step 4, the equipment and methods for stirring when stirring are not particularly limited, and known methods can be used. Specifically, there are devices equipped with a motor with stirring blades that can stir the cleaning liquid in a container, devices equipped with devices that generate ultrasonic waves, devices that can shake the entire container, wet crushers, kneaders, etc. The wet crusher can be the same as the crusher described in Steps 1 and 3.

[0139] (Rinse Liquid) The rinse liquid used in Step 4 can also be directly used as the cleaning liquid used when using the wet crusher in Step 1. Specifically, it may preferably contain an appropriate amount of an organic solvent. As the organic solvent, for example, it is preferable to contain one or more water-soluble alcohols and water-soluble solvents having a flash point of 21°C or higher. By using a water-soluble solvent in the rinse liquid, it is effective for peeling the ink film slightly remaining on the surface of the plastic film piece after Step 3. As the water-soluble solvent having a flash point of 21°C or higher, a water-soluble solvent among the organic solvents corresponding to Class II petroleum and Class III petroleum defined in the Fire Service Act is preferable. Further, as the water-soluble alcohols, alcohols defined in the Fire Service Act can be mentioned. Specifically, as Class II petroleum and Class III petroleum, 3-methoxy-3-methyl-1-butanol, diethylene glycol monobutyl ether, propylene glycol propyl ether, N-methylethanolamine, 2-ethylaminoethanol, isopropanolamine can be mentioned, and as alcohols, methanol, ethanol, 1-propyl alcohol, 2-propyl alcohol, etc. can be mentioned. Industrial ethanol containing these may be used alone or in combination.

[0140] Further, as the organic solvent, it may preferably contain the water-insoluble alcohols and water-insoluble glycol ether-based organic solvents described in Step 1. Among them, butan-1-ol, benzyl alcohol, ethylene glycol monophenyl ether (phenoxyethanol) are particularly preferable.

[0141] In particular, from the viewpoint of the peelability of the printed layer, the rinse liquid used in Step 4 preferably contains a large amount of a so-called water-soluble solvent containing alcohols in the cleaning liquid. Specifically, the water-soluble solvent is preferably 30% by mass or more, preferably 40% by mass or more, preferably 50% by mass or more, preferably 60% by mass or more, preferably 70% by mass or more, preferably 80% by mass or more, preferably 90% by mass or more, preferably 95% by mass or more.

[0142] In Step 4, when using a rinse solution mainly composed of a so-called water-soluble solvent containing alcohols that do not intentionally contain water, inorganic salts can be used.

[0143] (Inorganic salts) The inorganic salts used in the present invention may be those that can be used as grinding aids, and there are no particular limitations. However, from the perspective of removing inorganic salts in subsequent steps, it is preferably water-soluble to such an extent that 10 g or more dissolves in 100 g of water at normal temperature. Also, it is preferably insoluble to such an extent that no more than 10 mg dissolves in 100 g of the above-mentioned water-soluble organic solvent at normal temperature, and more preferably substantially insoluble in the organic solvent. Specifically, examples include sodium chloride, potassium chloride, calcium chloride, sodium sulfate, potassium sulfate, aluminum sulfate, etc., with sodium chloride, potassium chloride, sodium sulfate, and potassium sulfate being more preferred. The above inorganic salts can be used alone or in combination of two or more.

[0144] When using inorganic salts as grinding aids, the inorganic salts are preferably 100 to 2000% by mass, more preferably 300 to 1500% by mass, based on 100 of the plastic film. Also, the amount of the rinse solution is 5000 to 50000% by mass, preferably 10000 to 40000% by mass, based on 100 of the plastic film. The more inorganic salts there are with respect to the plastic film, the higher the peeling effect of the remaining printed layer, and the less the amount of the solvent at that time, the higher the effect.

[0145] When using inorganic salts as grinding aids, the treatment temperature is 120°C or lower, particularly preferably 20 to 70°C. The treatment time is preferably about 5 minutes to 3 hours.

[0146] The device for kneading a mixture of plastic crushed film pieces, inorganic salts (grinding aids), and water-soluble organic solvents that have undergone Process 3 may be any device that can mechanically grind plastic film pieces. As a specific example, a kneader can be cited. In addition to this, a paint shaker, a paint conditioner, batch kneaders such as the Super Mixer manufactured by Kawata Co., Ltd., the FM Mixer manufactured by Nippon Coke Co., Ltd., and the Trimix manufactured by Inoue Manufacturing Co., Ltd., and continuous kneaders such as the KCK Mill manufactured by Asada Iron Works Co., Ltd. can also be used. Devices other than these can also be used.

[0147] (Laminate) The laminate separated and recovered according to the present invention is a laminate having at least an adhesive layer and a release primer layer between a resin base material A and a resin base material B. In such a laminate, a laminate in which a printing layer is provided exposed on the resin base material surface (front printing), a laminate in which the printing layer is provided between a plurality of films (back printing), etc., generally laminates distributed as food packaging materials or packaging materials for daily necessities, etc., various types of laminates having resin layers discarded by recycling, etc. can be separated and recovered without particular limitation. That is, the separation and recovery method of the present invention is characterized in that there is no particular need for reclassification and they can be processed together.

[0148] In addition, for example, for containers such as PET bottles, a shrink label which is a laminated film formed in a cylindrical shape is used to give indications such as product names and decorativeness. At the time of recycling, consumers often peel off the shrink label and discard the PET bottle body and the shrink label separately. However, in the separation and recovery method of the present invention, even when the PET bottle body and the shrink label are integrated, the shrink label can be separated from the PET bottle body and the shrink label can be separated into each single-layer film.

[0149] Laminates laminated with a reactive adhesive often have an adhesive layer made of the reactive adhesive laminated between at least two resin film layers or metal foil or vapor deposition film layers. Specifically, in the laminate, if the resin film layer is expressed as (F), the metal foil layer of the metal foil or vapor deposition film layer is expressed as (M), and the adhesive layer such as the reactive adhesive is expressed as (AD), the following configurations can be considered as specific embodiments of the laminate, but of course it is not limited thereto. The description of the primer layer is omitted in the following specific configurations, but it is provided at an arbitrary position between two resin film layers (F). The primer layer preferably has one surface in contact with the adhesive layer and the other surface in contact with the resin film layer (F).

[0150] Note that one of the resin film layers (F) is a resin base material A and the other is a resin base material B. When there are three or more resin film layers (F), any one of the resin film layers (F) is a resin base material A, and the resin film layer (F) closest to the resin base material A is a resin base material (B). (F) / (AD) / (F), (F) / (AD) / (F) / (AD) / (F), (F) / (AD) / (M) / (AD) / (F), (F) / (AD) / (M), (F) / (AD) / (M) / (F), (F) / (AD) / (F) / (AD) / (M) / (AD) / (F), (F) / (AD) / (M) / (AD) / (F) / (AD) / (F), (M) / (AD) / (F) / (AD) / (M), (AD) / (F) / (AD) / (M), (AD) / (F) / (AD) / (F) / (AD), etc.

[0151] In the laminate of the present invention, more specifically, the following first configuration and second configuration can be mentioned.

[0152] <First Configuration> The first configuration is a laminate - type laminate in which an adhesive layer and a release primer layer are laminated between at least a resin base material A and a resin base material B. Between one of the resin base material A or the resin base material B and the adhesive layer, there is a release primer layer in contact with them, and the other of the resin base material A or the resin base material B does not contact the primer layer. Examples of such a configuration are as follows. ·(1 - 1) Substrate A / Adhesive layer / Primer layer / Substrate B ·(1 - 2) Substrate A / Primer layer / Adhesive layer / Substrate B By providing the primer layer between the adhesive layer and the substrate, the peeling of the laminate can be promoted.

[0153] Further, the laminate of the present invention may further have a printing layer, a barrier coat layer, a paper layer, an oxygen - absorbing layer, an anchor coat layer, a metal layer such as an aluminum foil, etc. For example, when having a printing layer, there are configurations of (1 - 3) and (1 - 4) in which the printing layer is provided on the surface of the laminate, and configurations of (1 - 5) and (1 - 6) in which the printing layer is provided on the surface opposite to the surface on which the primer layer is provided in the adhesive layer. ·(1 - 3) Printing layer / Substrate A / Adhesive layer / Primer layer / Substrate B ·(1 - 4) Printing layer / Substrate A / Primer layer / Adhesive layer / Substrate B ·(1 - 5) Substrate A / Printing layer / Adhesive layer / Primer layer / Substrate B ·(1 - 6) Substrate A / Primer layer / Adhesive layer / Printing layer / Substrate B The configurations of (1-5) and (1-6) above are such that the printing layer is provided between two base materials, making it difficult to peel off the printing layer. However, in the laminate of the present invention, by quickly peeling off the two base materials, the inner layer to be peeled off can be quickly exposed, and the peelability of the printing layer can be improved. In addition, in the conventional laminate, the peeling of the printing layer was promoted by providing a peeling treatment between the base material and the printing layer. However, when a primer layer is provided between the base material and the adhesive layer as in the laminate configuration of the present invention, the laminate can be peeled off more quickly than in the configuration where a primer layer is provided between the base material and the printing layer. That is, in order to promote the peeling of the laminate, it is efficient to provide a primer layer between the base material and the adhesive layer. Therefore, excellent peelability can be exhibited with a simple laminate configuration without having a primer layer between the base material and the printing layer as in (1-5) and (1-6) above.

[0154] In the above (1-1) to (1-6), the base material B often refers to a film formed on the surface of the laminate on the side opposite to the base material A. However, in some cases, it is not limited to the film arranged on the surface, and there may be cases where the base material A and / or the base material B exist between layers, and there may also be cases where a plurality of base materials A and / or base materials B are provided in the laminate. For example, the following configurations can be mentioned. ·(1-1-1) Base material A / Adhesive layer 1 / Primer layer / Base material B / Primer layer / Adhesive layer 2 / Sealing film ·(1-1-2) Base material A / Adhesive layer 1 / Primer layer / Base material B / Adhesive layer 2 / Sealing film ·(1-2-1) Base material A / Primer layer / Adhesive layer 1 / Base material B / Primer layer / Adhesive layer 2 / Sealing film ·(1-2-2) Base material A / Primer layer / Adhesive layer 1 / Base material B / Adhesive layer 2 / Sealing film ·(1-3-1) Printing layer / Base material A / Adhesive layer 1 / Primer layer / Base material B / Primer layer / Adhesive layer 2 / Sealing film ·(1-4-1) Printing layer / Base material A / Primer layer / Adhesive layer 1 / Base material B / Primer layer / Adhesive layer 2 / Sealing film ·(1-5-1) Substrate A / Printing layer / Adhesive layer 1 / Primer layer / Substrate B / Primer layer / Adhesive layer 2 / Sealant film ·(1-5-2) Substrate A / Printing layer / Adhesive layer 1 / Primer layer / Substrate B / Primer layer / Adhesive layer 2 / Metal layer / Adhesive layer 3 / Sealant film ·(1-5-3) Substrate A / Printing layer / Adhesive layer 1 / Metal layer / Adhesive layer 2 / Primer layer / Substrate B / Primer layer / Adhesive layer 3 / Sealant film ·(1-6―1) Substrate A / Primer layer / Adhesive layer 1 / Printing layer / Substrate B / Primer layer / Adhesive layer 2 / Sealant film ·(1-6-2) Substrate A / Primer layer / Adhesive layer 1 / Printing layer / Substrate B / Primer layer / Adhesive layer 2 / Metal layer / Adhesive layer 3 / Sealant film As the structure of the laminate of the first configuration, the above aspects are listed, but it is not limited thereto.

[0155] <Second configuration> As the second configuration, in a laminate type laminate in which an adhesive layer and a release primer layer are laminated at least between a resin substrate A and a resin substrate B, between one of the resin substrate A or the resin substrate B and the adhesive layer, there is a release primer layer in contact with these, and between the other of the resin substrate A or the resin substrate B and the adhesive layer, there is a printing layer and a second primer layer. That is, in the adhesive layer, there are a printing layer and a second release primer layer on the surface opposite to the surface on which the release primer layer is provided, and these are provided between the resin substrate A and the resin substrate B.

[0156] In the laminate of the second configuration, the primer layer provided between the adhesive layer and the substrate promotes the peeling of the laminate, and the second primer layer provided on the resin substrate that becomes the printing surface promotes the peeling of the printing layer.

[0157] When it is desired to further improve the peelability of the printing layer and / or the adhesive layer, it is preferable to adopt the second configuration. In this configuration, depending on the surfactant of the cleaning agent used in Step 2, the peeling state of the printing layer and / or the adhesive layer can be controlled. Specifically, when a nonionic surfactant with an HLB of less than 12.5 is used in Step 2, the printing layer and / or the adhesive layer can be recovered in the form of a film. On the other hand, when a nonionic surfactant with an HLB of 12.5 or more is used, the printing layer and / or the adhesive layer can be recovered in the form of powder. When performing specific gravity separation in a liquid after Step 3 described later, it is preferable that the printing layer and / or the adhesive layer can be recovered in the form of a film. In the case of a film, it separates and precipitates from the resin base material (plastic crushed material), but in the case of powder, it easily enters between the plastic crushed materials, making separation difficult. In the second configuration, when a nonionic surfactant with an HLB of 12.5 or more is used, the size of the powder recovered in Step 3 is 1 mm or less. On the other hand, the size of the film recovered using a nonionic surfactant with an HLB of less than 12.5 is close to that of the laminate crushed in Step 1, and its long side is 1 mm to 30 mm.

[0158] Specific examples of the laminate with the second configuration include the following. ·(2-1) Substrate A / Primer layer 2 / Printing layer / Adhesive layer / Primer layer / Substrate B ·(2-2) Substrate A / Primer layer / Adhesive layer / Printing layer / Primer layer 2 / Substrate B Similar to the first laminate, the laminate with the second configuration may further have a barrier coat layer, a paper layer, an oxygen absorption layer, an anchor coat layer, a metal layer such as an aluminum foil, etc. Also, Substrate A and Substrate B are not limited to the films arranged on the surface, and there may be cases where Substrate A and / or Substrate B exist between layers, and there may also be cases where a plurality of Substrate A and / or Substrate B are provided in the laminate. For example, the following configurations can be cited. ·(2-1-1) Substrate A / Primer layer 2 / Printing layer / Adhesive layer 1 / Primer layer / Substrate B / Primer layer / Adhesive layer 2 / Sealant film ·(2-1-2) Substrate A / Primer layer 2 / Printing layer / Adhesive layer 1 / Primer layer / Substrate B / Primer layer / Adhesive layer 2 / Metal layer / Adhesive layer 3 / Sealant film ·(2-1-3) Substrate A / Primer layer 2 / Printing layer / Adhesive layer 1 / Metal layer / Adhesive layer 2 / Primer layer / Substrate B / Primer layer / Adhesive layer 3 / Sealant film ·(2-1-4) Substrate A / Primer layer 2 / Printing layer / Adhesive layer 1 / Primer layer / Substrate B / Adhesive layer 2 / Sealant film ·(2-2―1) Substrate A / Primer layer / Adhesive layer 1 / Printing layer / Primer layer 2 / Substrate B / Primer layer / Adhesive layer 2 / Sealant film ·(2-2-2) Substrate A / Primer layer / Adhesive layer 1 / Printing layer / Primer layer 2 / Substrate B / Primer layer / Adhesive layer 2 / Metal layer / Adhesive layer 3 / Sealant film ·(2-2―3) Substrate A / Primer layer / Adhesive layer 1 / Printing layer / Primer layer 2 / Substrate B / Adhesive layer 2 / Sealant film As the structure of the laminate, the above aspects are listed, but it is not limited thereto.

[0159] (Coat layer) There may be a functional coat layer on the outermost surface of the above laminate film structure. The coat layer may be colorless or colored. The coat layer may be provided in contact with the substrate, or may be provided via an inorganic vapor deposition layer or the like in contact with the substrate. The coat layer may be in a form in which different coat layers are laminated. There is no particular limitation on the thickness of the coat layer, but preferably it is 0.1 μm or more and 100 μm or less, more preferably 0.1 μm or more and 10 μm or less, and still more preferably 1 μm or more and 5 μm or less.

[0160] The functional coat layer is formed for various purposes. Typical functions include hard coat, silicone-based release, IR cut, waterproof and moisture-proof, antibacterial, UV cut, heat dissipation, photocatalyst, weather resistance, antifogging, fingerprint-resistant and antifouling, self-healing, water and oil repellency, etc.

[0161] The laminated film targeted by this separation and recovery method may further have a paper layer, an oxygen absorption layer, an anchor coat layer, a printing layer, a primer layer for desorption provided to facilitate the peeling of the ink, and the like.

[0162] (Primer layer) The laminate of the present invention has a primer layer between the resin substrate A and the resin substrate B. By having a primer layer in the laminate, the peelability can be further improved in Steps 2 and 3. By providing a primer layer, the recyclability of the film can be improved, and the quality of the recycled plastic can also be improved. In particular, by providing a desorption primer layer as a layer in contact with the substrate and the adhesive layer, the laminated film can be separated into single-layer films, and when having a printing layer, the peeling of the printing layer can be facilitated.

[0163] The printing ink is printed on the resin substrate that becomes the substrate film layer (F1) in the laminate, then the reactive adhesive is applied to the printed surface, and it is often laminated with another substrate film (F1), a sealant layer (F2), a metal foil, or a metal foil layer (M) of a vapor deposition film layer to form a laminate. In a laminate having this layer structure, it is also possible and preferable to provide a primer layer on the substrate film layer (F1) that becomes the printing surface or between the substrate film (F1) and the adhesive layer (AD). Since the primer is easily dissolved or hydrolyzed by an alkaline solution, it preferably contains a resin having an acidic group, and it becomes possible to easily separate the laminated film printed with the ink and then laminated with an adhesive into single-layer films.

[0164] The primer may be provided on the sealant layer (F2), or may be provided on both F1 and F2. If primers are provided on both F1 and F2, the separation into single-layer films can be made even easier.

[0165] For the primer layer, a resin or a low-molecular compound having an acidic group can be used alone. Also, a resin having no acidic group can be used by mixing with a resin or a low-molecular compound having an acidic group. Examples of the resin having an acidic group include resins having an acid value such as rosin-modified maleic acid resin and rosin-modified fumaric acid resin, polymerizable monomers having a carboxyl group such as acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, cinnamic acid or their acid anhydrides, polymerizable monomers having a sulfonic acid group such as sulfonated styrene, polymerizable monomers having a sulfonamide group such as vinylbenzenesulfonamide, etc., (meth)acrylic resins, styrene-(meth)acrylic resins, styrene-(anhydrous)maleic acid resins, terpene-(anhydrous)maleic acid resins, etc. which are radical copolymers obtained by copolymerizing polymerizable monomers having an acidic group, and acid-modified polyolefin resins, etc. These can be used alone or in combination of two or more.

[0166] In addition, for the primer layer, a low-acid-value resin having film-forming property at normal temperature can be used by mixing with one or more low-molecular compounds having an acidic group.

[0167] Examples of the low-molecular compound having an acidic group include saturated fatty acids, unsaturated fatty acids, hydroxy acids, aromatic carboxylic acids, dicarboxylic acids, tricarboxylic acids, oxocarboxylic acids, carboxylic acid derivatives, acid anhydrides, etc. These can be used alone or in combination of two or more.

[0168] Examples of saturated fatty acids include lauric acid, myristic acid, palmitic acid, margaric acid, stearic acid, etc.; examples of unsaturated fatty acids include oleic acid, linoleic acid, linolenic acid, arachidonic acid, eicosapentaenoic acid, docosahexaenoic acid, sorbic acid, etc.; examples of hydroxy acids include lactic acid, malic acid, citric acid, etc.; examples of aromatic carboxylic acids include benzoic acid, phthalic acid, isophthalic acid, terephthalic acid, salicylic acid, gallic acid, mellitic acid, cinnamic acid, etc.; examples of dicarboxylic acids include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, fumaric acid, maleic acid, etc.; examples of tricarboxylic acids include aconitic acid, etc.; examples of oxocarboxylic acids include pyruvic acid, oxaloacetic acid, etc.; examples of carboxylic acid derivatives include amino acids, nitrocarboxylic acids; examples of acid anhydrides include trimellitic anhydride, pyromellitic anhydride, etc. These can be used singly or as a mixture of two or more of them.

[0169] Examples of the resin having film-forming properties at normal temperature include various synthetic resins, such as polyester, copolymers of polyvinyl chloride or vinyl chloride and other unsaturated double bond-containing monomers, homopolymers of (meth)acrylic acid esters or copolymers of (meth)acrylic acid esters and other unsaturated double bond-containing monomers, polystyrene or copolymers of styrene monomers and other unsaturated double bond-containing monomers, ketone-formaldehyde condensates and their hydrogenated products, polyfunctional epoxy resins, polyvinyl acetals, polyurethanes, etc. These can be used alone or in combination of one or more selected from these. Examples of polyfunctional epoxy compounds include bisphenol A novolak type epoxy resin, bisphenol F novolak type epoxy resin, bisphenol S novolak type epoxy resin, biphenyl type epoxy resin, naphthalene type epoxy resin, etc.

[0170] When using the resin with a low acid value and film-forming property at normal temperature by mixing one or more low-molecular compounds having acidic groups, the addition amount may be appropriately determined within a range that does not impair the printing suitability or coating suitability of the primer solution, but is generally preferably in the range of 0.5 to 50% by weight, more preferably in the range of 1.0 to 30% by weight based on the solid content of the primer solution.

[0171] When the object to be printed is, for example, polypropylene (PP), as the resin having film-forming property, at least one thermoplastic resin that is solid at 50°C and is selected from the group consisting of a ketone-formaldehyde condensate and its hydrogenated product, polyester, vinyl chloride-vinyl acetate copolymer, and polyvinyl acetal, which have good adhesion to PP by themselves, is preferably used. As such a ketone-formaldehyde condensate and its hydrogenated product, Evonik Degussa Japan Co., Ltd.'s TEGO (registered trademark) VariPlus series (SK, A P, etc.), as polyester, Toyobo Co., Ltd.'s BYRON (registered trademark) series (BYRON 200, etc.), as vinyl chloride-vinyl acetate copolymer, Nisshin Chemical Kogyo Yuyu Co., Ltd.'s Solvain (registered trademark) series (Solvain AL, etc.), and as polyvinyl acetal, Sekisui Chemical Co., Ltd.'s Esrec (registered trademark) series (Esrec KS-10, etc.) can be mentioned.

[0172] To form a primer layer on a substrate, the solution adjusted using each of the above components is applied to the substrate and dried. The coating amount is about 0.1 to 5 μm (dry thickness), but if it is less than 0.1, it is difficult to apply uniformly, and if it exceeds 5 μm, it is uneconomical and not practical. Coating is performed by ordinary coating methods, for example, gravure, letterpress, flexo, roll coater, reverse coater, spray method, etc. The formation of the primer layer and the printing thereon may be continuous (inline) or the formation of the primer layer and printing may be performed separately.

[0173] When printing is carried out inline immediately after primer coating using a printing machine such as roll-to-roll, depending on the re-dissolvability of the resin used for the primer layer in the ink solvent and the glass transition point (Tg) of the resin itself, so-called blocking occurs where the printed surface adheres to the back surface of the substrate. To prevent such blocking, transparent particles with a particle size of 0.1 μm to 10 μm such as silica and titanium oxide may be mixed into the primer solvent at about 0.005 to 5% with respect to the total amount of the primer as an anti-blocking agent.

[0174] Also, for the purpose of preventing blocking, the resin solution with a high acid value used for the primer may be neutralized in advance with ammonia or the like before coating to prevent re-dissolvability in the solvent contained in the printing ink.

[0175] The acid value of the compound having the acidic group is not particularly limited, but is preferably 150 mgKOH / g or more.

[0176] In the laminated film using the aforementioned primer layer, when the printing design is based on white, almost no white ink is used in the printing layer, and the film laminated with the adhesive may be difficult to peel off with a low-temperature or low-concentration alkaline solution. In that case, the peelability of the printing layer can be further improved by introducing a medium layer used in the printing ink between the primer layer and the white ink layer, or between the white ink layer and the adhesive layer.

[0177] Among them, in the present invention, a primer layer containing a urethane resin or polyvinyl alcohol is preferred, and it is more preferably formed using a composition containing a urethane resin or polyvinyl alcohol having an acid value of 8 to 45 mgKOH / g.

[0178] As a preferred embodiment of the primer layer-forming composition, a primer layer-forming composition of a first embodiment which is an aqueous urethane resin composition and a primer layer-forming composition of a second embodiment containing polyvinyl alcohol can be mentioned. Hereinafter, the primer layer-forming compositions of these embodiments will be described.

[0179] <<Composition for forming primer layer of the first aspect>> As a first aspect of the composition for forming a primer layer, a composition for forming a primer layer comprising an aqueous urethane resin composition can be mentioned.

[0180] The aqueous urethane resin composition according to the present invention contains a urethane resin (A) and an aqueous medium (B).

[0181] The aqueous urethane resin composition according to the present invention is a dispersion of a urethane resin (A) obtained by reacting an aromatic polyester polyol (a1) containing an aromatic dicarboxylic acid (a1-1) as a raw material monomer with a polyisocyanate (a2) and, if necessary, a chain extender or the like in an aqueous medium (B).

[0182] The aromatic ring concentration derived from the raw material monomer of the aromatic dicarboxylic acid (a1-1) in the urethane resin (A) is, for example, 1 mmol / g or more.

[0183] The ester bond group concentration in the urethane resin (A) is, for example, 1 mmol / g or more.

[0184] The acid value of the urethane resin (A) is, for example, 8 to 45 mgKOH / g.

[0185] <<<Urethane resin (A)>>> The urethane resin (A) is a general term for polymer compounds having a urethane bond (-NHCOO-), and in the present invention, it is composed of a reaction product obtained by reacting an aromatic polyester polyol (a1) and a polyisocyanate (a2) (crosslinking and curing reaction).

[0186] The urethane resin (A) may further contain another polyol (a3) in addition to the aromatic polyester polyol (a1) and the polyisocyanate (a2), and may be a reaction product of the aromatic polyester polyol (a1), the polyisocyanate (a2), and the other polyol (a3).

[0187] - Aromatic polyester polyol (a1)- The aromatic polyester polyol (a1) can be produced, for example, by subjecting an aromatic dicarboxylic acid (a1-1) and a polyol (a1-2) to an esterification reaction.

[0188] Examples of the aromatic dicarboxylic acid (a1-1) that can be used when producing the aromatic polyester polyol (a1) include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, orthophthalic acid, 1,4-naphthalenedicarboxylic acid, 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, naphthalic acid, biphenyldicarboxylic acid, 1,2-bis(phenoxy)ethane-P,P'-dicarboxylic acid, and their acid anhydrides or ester-forming derivatives; aromatic hydroxycarboxylic acids such as p-hydroxybenzoic acid and their ester-forming derivatives; and sulfonic acid group-containing aromatic dicarboxylic acids such as 5-sulfoisophthalic acid and their ester-forming derivatives.

[0189] In addition to such aromatic dicarboxylic acids (a1-1), aliphatic carboxylic acids and alicyclic carboxylic acids can be used in combination. Examples include aliphatic dicarboxylic acids such as succinic acid, succinic anhydride, adipic acid, suberic acid, azelaic acid, sebacic acid, dimer acid, maleic anhydride, fumaric acid; alicyclic dicarboxylic acids such as 1,4-cyclohexanedicarboxylic acid; and their anhydrides or ester-forming derivatives. These can be used alone or in combination of two or more.

[0190] Examples of the polyol (a1-2) that can be used include ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, dipropylene glycol, 1,4-butanediol, 1,3-butanediol, 1,2-butanediol, 2,3-butanediol, 1,5-pentanediol, 1,5-hexanediol, 2,5-hexanediol, 1,6-hexanediol, 1,7-heptanediol, neopentyl glycol, etc.

[0191] Specifically, an aromatic dicarboxylic acid (a1-1) and a polyol (a1-2) can be reacted under normal pressure or reduced pressure in a reaction vessel substituted with an inert gas such as nitrogen in the presence of a catalyst as necessary. The reaction is preferably carried out in the range of 100°C to 300°C.

[0192] As the catalyst, for example, acetates of alkali metals or alkaline earth metals, compounds containing zinc, manganese, cobalt, antimony, germanium, titanium, tin, zirconium, etc. can be used. Among them, it is preferable to use tetraalkyl titanate or tin oxalate effective for transesterification reaction, polycondensation reaction, etc.

[0193] When producing the urethane resin (A), an aromatic polyester polyol (a1), a polyisocyanate (a2), and other polyols (a3) etc. can also be used in combination.

[0194] As the other polyol (a3), the same polyols as the above polyol (a1-2) can be used, and for example, relatively low molecular weight polyols such as ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, dipropylene glycol, 1,4-butanediol, 1,3-butanediol, 1,2-butanediol, 2,3-butanediol, 1,5-pentanediol, 1,5-hexanediol, 2,5-hexanediol, 1,6-hexanediol, 1,7-heptanediol, neopentyl glycol can be used.

[0195] - Polyisocyanate (a2) - Examples of the polyisocyanate (a2) that reacts with the polyol (a1) to form the urethane resin (A) include aromatic diisocyanates such as phenylenediisocyanate, tolylene diisocyanate, diphenylmethane diisocyanate, and naphthalene diisocyanate, and aliphatic or aliphatic cyclic structure-containing diisocyanates such as hexamethylene diisocyanate, lysine diisocyanate, cyclohexane diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, xylylene diisocyanate, and tetramethylxylylene diisocyanate. These can be used alone or in combination of two or more. Among them, it is more preferable to use one or more selected from the group consisting of isophorone diisocyanate, tolylene diisocyanate, hexamethylene diisocyanate, and dicyclohexylmethane diisocyanate from the viewpoints of improving the substrate adhesion and peelability of the resulting primer layer.

[0196] The urethane resin (A) can be produced, for example, by reacting the aromatic polyester polyol (a1), the polyisocyanate (a2), the polyol (a3) as needed, and a chain extender as needed in the absence of a solvent or in the presence of an organic solvent. When the organic solvent is used, it is preferable to remove the organic solvent by a method such as distillation as needed when dispersing the urethane resin (A) in the aqueous medium (B).

[0197] Examples of the organic solvent that can be used in the production of the urethane resin (A) include ketones such as acetone and methyl ethyl ketone; ethers such as tetrahydrofuran and dioxane; acetate esters such as ethyl acetate and butyl acetate; nitriles such as acetonitrile; dimethylformamide, N-methylpyrrolidone, etc. These can be used alone or in combination of two or more.

[0198] The chain extender that can be used in the production of the urethane resin (A) can be used for the purpose of increasing the molecular weight of the urethane resin (A) and improving the durability of the resulting film or the like.

[0199] As the chain extender that can be used when producing the urethane resin (A), polyamines, other active hydrogen atom-containing compounds, etc. can be used.

[0200] Examples of polyamines include diamines such as ethylenediamine, 1,2-propanediamine, 1,6-hexamethylenediamine, piperazine, 2,5-dimethylpiperazine, isophoronediamine, 4,4'-dicyclohexylmethanediamine, 3,3'-dimethyl-4,4'-dicyclohexylmethanediamine, 1,4-cyclohexanediamine; N-hydroxymethylaminoethylamine, N-hydroxyethylaminoethylamine, N-hydroxypropylaminopropylamine, N-ethylaminoethylamine, N-methylaminopropylamine; diethylenetriamine, dipropylenetriamine, triethylenetetramine; hydrazine, N,N'-dimethylhydrazine, 1,6-hexamethylenebishydrazine; succinic acid dihydrazide, adipic acid dihydrazide, glutaric acid dihydrazide, sebacic acid dihydrazide, isophthalic acid dihydrazide; β-semicarbazidopropionic acid hydrazide, 3-semicarbazidopropyl-carbazinic acid ester, semicarbazide-3-semicarbazidomethyl-3,5,5-trimethylcyclohexane can be used, and ethylenediamine is preferably used.

[0201] Examples of other active hydrogen-containing compounds include glycols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, hexamethylene glycol, neopentyl glycol, sucrose, methylene glycol, glycerin, sorbitol; phenols such as bisphenol A, 4,4'-dihydroxydiphenyl, 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxydiphenyl sulfone, hydrogenated bisphenol A, hydroquinone, and water, etc. can be used.

[0202] The chain extender can be used when reacting the aromatic polyester polyol (a1) and the polyisocyanate (a2), or after the reaction. Also, when dispersing the urethane resin (A) in an aqueous medium (B) to make it aqueous, a chain extender can also be used.

[0203] -Properties of the urethane resin (A)- The aromatic ring concentration derived from the raw material monomer of the aromatic dicarboxylic acid (a1-1) in the urethane resin (A) is preferably 1 mmol / g or more.

[0204] Such aromatic ring concentration is determined by calculating the number of moles of aromatic rings contained in 1 g of the urethane resin (A).

[0205] The specific calculation method will be described later.

[0206] From the viewpoints of improving the substrate adhesion and peelability of the resulting primer layer, etc., the aromatic ring concentration is preferably 1.5 mmol / g or more, more preferably 2 mmol / g or more, and from the viewpoints of good film-forming properties of the primer layer, etc., it is preferably 6 mmol / g or less, more preferably 5 mmol / g or less.

[0207] The ester bond group concentration in the urethane resin (A) is preferably 1 mmol / g or more. Such ester bond group concentration is determined by calculating the number of moles of ester bond groups contained in 1 g of the urethane resin (A). The specific calculation method will be described later.

[0208] From the viewpoints of improving the substrate adhesion and peelability of the resulting primer layer, etc., the ester bond group concentration is preferably 2 mmol / g or more, more preferably 4 mmol / g or more, and from the viewpoints of good blocking resistance of the primer layer, etc., it is preferably 9 mmol / g or less, more preferably 7 mmol / g or less.

[0209] The acid value of the urethane resin (A) is preferably 8 to 45 mgKOH / g. The acid value is the value obtained by converting the amount of acid in 1 g of the resin, which is calculated by titrating the acid with an alkali, into milligrams of potassium hydroxide, and is the value obtained according to JIS K0070.

[0210] If the acid value is 8 mgKOH / g or more, the water dispersion stability can be improved, preferably 15 mgKOH / g or more, more preferably 20 mgKOH / g or more. If the acid value is 45 mgKOH / g or less, the adhesion to the substrate can be ensured to be good, preferably 40 mgKOH / g or less, more preferably 30 mgKOH / g or less.

[0211] The value obtained by dividing the mass of the raw material monomer of the polyisocyanate (a2) contained in 1 g of the urethane resin (A) by the NCO equivalent weight of the raw material monomer of the polyisocyanate (a2) is preferably 1.0 to 6.0 mmol / g.

[0212] If such a value is 1.0 mmol / g or more, the adhesion and peelability of the obtained primer layer to the substrate can be improved, more preferably 1.5 mmol / g or more, still more preferably 1.8 mmol / g or more. If it is 6.0 mmol / g or less, the film-forming property of the primer layer can be ensured, more preferably 5.0 mmol / g or less, still more preferably 4.0 mmol / g or less.

[0213] The weight average molecular weight of the urethane resin (A) is preferably 10,000 to 100,000. From the viewpoints of blocking resistance to the substrate, hydrolysis resistance stability of the resin, etc., the weight average molecular weight of the urethane resin (A) is preferably 20,000 or more, more preferably 30,000 or more. Also, from the viewpoints of reducing the viscosity during water dispersion, productivity, etc., it is preferably 80,000 or less, more preferably 60,000 or less.

[0214] In the present invention, the weight average molecular weight was measured by the gel permeation chromatography (GPC) method. The measurement conditions are as described above.

[0215] The glass transition temperature of the urethane resin (A) is preferably from 0 to 110 °C.

[0216] <<<aqueous medium (B)>>> Examples of the aqueous medium (B) that serves as a solvent for the urethane resin (A) include water, organic solvents miscible with water, and mixtures thereof.

[0217] Examples of the organic solvents miscible with water include alcohols such as methanol, ethanol, n- and isopropanol; ketones such as acetone and methyl ethyl ketone; polyalkylene glycols such as ethylene glycol, diethylene glycol, and propylene glycol; alkyl ethers of polyalkylene glycols; and N-methyl-2-pyrrolidone.

[0218] In the present invention, only water may be used, or a mixture of water and an organic solvent miscible with water may be used, or only an organic solvent miscible with water may be used. From the viewpoints of safety and environmental load, only water or a mixture of water and an organic solvent miscible with water is preferable, and only water is particularly preferable.

[0219] When the urethane resin (A) is dispersed in water in the aqueous medium (B), a machine such as a homogenizer can be used as necessary.

[0220] The aqueous urethane resin composition of the present invention preferably contains the urethane resin (A) in the range of 5% by mass to 50% by mass, more preferably in the range of 10% by mass to 25% by mass, based on the total amount of the aqueous urethane resin composition. Further, the aqueous medium (B) preferably contains in the range of 50% by mass to 95% by mass, more preferably in the range of 75% by mass to 90% by mass, based on the total amount of the urethane resin composition.

[0221] <<<other additives>>> In the aqueous urethane resin composition according to the present invention, various additives such as a film-forming aid, a crosslinking agent, a curing accelerator, a plasticizer, an antistatic agent, a wax, a light stabilizer, a flow regulator, a dye, a leveling agent, a rheology control agent, an ultraviolet absorber, an antioxidant, a photocatalytic compound, an inorganic pigment, an organic pigment, and an extender pigment can be used as needed.

[0222] Among the additives, emulsifiers and leveling agents may cause a decrease in the durability of the resulting film or the like. Therefore, when high durability is required for the film or the like, it is preferably used in a range of 5% by mass or less based on the total amount of the aqueous urethane resin composition.

[0223] In addition, in the aqueous urethane resin composition of the present invention, various crosslinking agents can be used in combination to form a film or the like having excellent durability.

[0224] Examples of the crosslinking agent include isocyanate-based crosslinking agents, epoxy-based crosslinking agents, amino-based crosslinking agents, aziridine-based crosslinking agents, silane coupling agent-based crosslinking agents, carbodiimide-based crosslinking agents, and oxazolidine-based crosslinking agents.

[0225] From the viewpoints of improving the adhesion to the substrate and the peelability, etc., the crosslinking agent is preferably used in a range of 30% by mass or less, more preferably in a range of 20% by mass or less based on the total amount of the urethane resin (A). Further, the crosslinking agent is preferably mixed and used immediately before coating the aqueous urethane resin composition of the present invention.

[0226] <<Composition for forming a primer layer of the second aspect>> As a second aspect of the composition for forming a primer layer, a composition for forming a primer layer containing polyvinyl alcohol can be mentioned.

[0227] The primer layer containing polyvinyl alcohol is preferably a resin layer containing at least 25% by mass of polyvinyl alcohol. Hereinafter, the resin layer containing polyvinyl alcohol may be referred to as a PVA resin layer.

[0228] Polyvinyl alcohol is a colorless powder obtained by saponifying polyvinyl acetate. It is a water-soluble thermoplastic resin and serves as the raw material for the synthetic fiber vinylon. Generally, it may also be abbreviated as Poval or PVA. Examples of commercially available products include Poval manufactured by Kuraray Co., Ltd., Elvanol, Exceval, Gosenol manufactured by Mitsubishi Chemical Corporation, and Nippon Vinyl Poval Co., Ltd.

[0229] The saponification degree of polyvinyl alcohol is determined by the ratio of vinyl groups in polyvinyl acetate substituted with hydroxyl groups, and it is preferably 90% or more. Examples of polyvinyl alcohol with a saponification degree of 90% or more include, but are not limited to, the following commercially available products.

[0230] Poval "3-98, 5-98, 28-98, 60-98, 27-96" manufactured by Kuraray Co., Ltd., Elvanol "71-30, 90-50, T-25, T-66" manufactured by Kuraray Co., Ltd., Exceval "AQ-4104, HR-3010, RS-2117, RS-1717" manufactured by Kuraray Co., Ltd., Gosenol "N-300, NL-05, A-300, AL-06R" manufactured by Mitsubishi Chemical Corporation, Nippon Vinyl Poval Co., Ltd. "JC-25, JC-33, JC-40, JF-02, JF-03, JF-04, JF-05, JF-10, JF-17, JF-17L, JF-22, JM-17, JM-17L, JM-23, JM-26, JM-33, JT-05, JT-13Y", etc.

[0231] The composition for forming a primer layer containing polyvinyl alcohol can be obtained by mixing the above-described aqueous medium (B) with polyvinyl alcohol (C).

[0232] In addition, the resin composition containing polyvinyl alcohol according to the present invention can contain various additives, etc. as necessary. The additives are, for example, as described in the above <<<Other Additives>>> column.

[0233] By applying the composition for forming a primer layer of the present invention onto a substrate, a detachable primer layer can be formed. The primer layer can be easily detached by treatment with an alkaline solution.

[0234] (Adhesive layer) As the adhesive used for the adhesive layer, any adhesive that can be used in general lamination methods may be used. Examples of lamination methods include dry lamination and wet lamination using a solvent-based adhesive for lamination, and non-solvent lamination using a solvent-free adhesive for lamination.

[0235] Examples of the solvent-based or solvent-free adhesive for lamination include one-component or two-component curable or non-curable types of vinyl resins, (meth)acrylic resins, polyamide resins, polyester resins, polyether resins, polyurethane resins, epoxy resins, rubber resins, and other adhesives.

[0236] The solvent used for the solvent-based adhesive for lamination is not particularly limited, and for example, a (organic) solvent-based adhesive diluted with an organic solvent, an aqueous-type adhesive diluted with an aqueous solvent, an emulsion-type adhesive, etc. can be used.

[0237] From the viewpoints of curing speed and adhesive strength, a two-component curable polyurethane resin adhesive, a solvent-based or solvent-free two-component curable adhesive composed of a polyol and an isocyanate compound, is often used.

[0238] The solvent-based or solvent-free adhesive for lamination can be applied, for example, by a direct gravure roll coating method, a gravure offset roll coating method, a kiss coating method, a reverse roll coating method, a fountain method, a transfer roll coating method, or other methods.

[0239] The laminate of the present invention exhibits excellent effects even in a laminated film laminated with a reactive adhesive that is difficult to peel. As the reactive adhesive, any commercially available reactive adhesive can be separated and recovered without particular limitation. Among them, the so-called two-component type of a polyisocyanate composition and a polyol composition, or a one-component type reactive adhesive of polyisocyanate is particularly preferable because it can exhibit particularly effective effects.

[0240] <<Reactive Adhesive Polyisocyanate Composition>> The polyisocyanate composition used in a general reactive adhesive is a composition containing a polyisocyanate compound as a main component, and any polyisocyanate compound known as a polyisocyanate compound for reactive adhesives can be used without particular limitation. Examples of specific polyisocyanate compounds include polyisocyanates having an aromatic structure in the molecular structure such as tolylene diisocyanate, diphenylmethane diisocyanate, polymeric diphenylmethane diisocyanate, 1,5-naphthalene diisocyanate, triphenylmethane triisocyanate, xylylene diisocyanate, etc.; compounds obtained by modifying a part of the isocyanate groups (NCO groups) of these polyisocyanates with carbodiimide; polyisocyanates having an alicyclic structure in the molecular structure such as isophorone diisocyanate, 4,4'-methylenebis(cyclohexyl isocyanate), 1,3-(isocyanatomethyl)cyclohexane, etc.; linear aliphatic polyisocyanates such as 1,6-hexamethylene diisocyanate, 1,5-pentamethylene diisocyanate, lysine diisocyanate, trimethylhexamethylene diisocyanate, etc.; compounds obtained by modifying a part of the NCO groups of these polyisocyanates with carbodiimide; Isocyanurate forms of the above various polyisocyanates; allophanate forms derived from the above various polyisocyanates; biuret forms derived from the above various polyisocyanates; adduct forms obtained by modifying the above various polyisocyanates with trimethylolpropane; polyisocyanates that are reaction products of the above various polyisocyanates and the polyol component described below, etc. can be mentioned.

[0241] <<Reactive Adhesive Polyol Composition>> The polyol composition used in general reactive adhesives is a composition containing a polyol compound as the main component, and any polyol compound known as a polyol compound for reactive adhesives can be used without particular limitation. Examples of specific polyol compounds include, for example, ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, methylpentanediol, dimethylbutanediol, butylethylpropanediol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, bishydroxyethoxybenzene, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, triethylene glycol and other glycols; glycerin, trimethylolpropane, pentaerythritol and other trifunctional or tetrafunctional aliphatic alcohols; bisphenol A, bisphenol F, hydrogenated bisphenol A, hydrogenated bisphenol F and other bisphenols; dimer diol, and polymer polyols selected from polyester polyols, polyether polyols, polyurethane polyols, polyether ester polyols, polyester (polyurethane) polyols, polyether (polyurethane) polyols, polyester amide polyols, acrylic polyols, polycarbonate polyols, polyhydroxyl alkanes, castor oil or mixtures thereof can be mentioned.

[0242] Among them, since it is easily dissolved or hydrolyzed by an alkaline solution, it is preferable that any of the constituent components of the reactive adhesive has an ester bond, and it can be easily separated into a single-layer film in a short time in the immersion treatment in the alkaline solutions in Step 2 and Step 3.

[0243] When any of the components of the reactive adhesive has an ester bond, specifically, it refers to a polyol composition having a polyol compound such as a polyester polyol, a polyether ester polyol, a polyester (polyurethane) polyol, or an acrylic polyol having an ester bond, or a reactive adhesive containing either or both of a polyisocyanate composition having a polyisocyanate compound which is a reaction product of the polyol compound having the ester bond and the various polyisocyanates.

[0244] In addition to the polyol composition and the polyisocyanate composition, a reactive adhesive to which a resin or a low molecular compound having an acidic group is added can also be preferably used. As the resin or the low molecular compound having an acidic group, it can be easily mixed with the polyol composition and the polyisocyanate composition which are the main components of the reactive adhesive (in this case, a solvent described later may be used if necessary), and any resin or low molecular compound having an acid value can be used without particular limitation.

[0245] Examples of the resin having an acidic group include resins having an acid value such as rosin-modified maleic acid resin and rosin-modified fumaric acid resin; radical copolymers such as (meth)acrylic resin, styrene-(meth)acrylic resin, styrene-(anhydrous)maleic acid resin, and terpene-(anhydrous)maleic acid resin obtained by copolymerizing a polymerizable monomer having an acidic group such as a polymerizable monomer having a carboxyl group such as acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, cinnamic acid, or their acid anhydrides, a polymerizable monomer having a sulfonic acid group such as sulfonated styrene, and a polymerizable monomer having a sulfonamide group such as vinylbenzenesulfonamide; and acid-modified polyolefin resins, etc. These can be used alone or in combination of two or more.

[0246] Examples of the low molecular weight compound having an acidic group include saturated fatty acids, unsaturated fatty acids, hydroxy acids, aromatic carboxylic acids, dicarboxylic acids, tricarboxylic acids, oxocarboxylic acids, carboxylic acid derivatives, acid anhydrides, etc., and these can be used alone or in combination of two or more.

[0247] Examples of the saturated fatty acids include lauric acid, myristic acid, palmitic acid, margaric acid, stearic acid, etc.; examples of the unsaturated fatty acids include oleic acid, linoleic acid, linolenic acid, arachidonic acid, eicosapentaenoic acid, docosahexaenoic acid, sorbic acid, etc.; examples of the hydroxy acids include lactic acid, malic acid, citric acid, etc.; examples of the aromatic carboxylic acids include benzoic acid, phthalic acid, isophthalic acid, terephthalic acid, salicylic acid, gallic acid, mellitic acid, cinnamic acid, etc.; examples of the dicarboxylic acids include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, fumaric acid, maleic acid, etc.; examples of the tricarboxylic acids include aconitic acid, etc.; examples of the oxocarboxylic acids include pyruvic acid, oxaloacetic acid, etc.; examples of the carboxylic acid derivatives include amino acids, nitrocarboxylic acids, etc.; examples of the acid anhydrides include trimellitic anhydride, pyromellitic anhydride, etc., and these can be used alone or in combination of two or more.

[0248] The acid value of the resin or low molecular weight compound having the acidic group is not particularly limited, but is preferably 150 mgKOH / g or more.

[0249] It is preferable that at least one of the glass transition point, softening point, and melting point of the resin or low molecular weight compound having the acidic group is 100°C or higher.

[0250] In addition, additives such as pigments, silane coupling agents, titanate coupling agents, coupling agents such as aluminum-based ones, adhesion promoters such as epoxy resins, leveling agents, inorganic fine particles such as colloidal silica and alumina sol, organic fine particles of polymethyl methacrylate, defoamers, sag prevention agents, wetting dispersants, viscosity modifiers, ultraviolet absorbers, metal deactivators, peroxide decomposers, flame retardants, reinforcing agents, plasticizers, lubricants, rust preventives, fluorescent brighteners, inorganic heat ray absorbers, flameproofing agents, antistatic agents, dehydrating agents, etc. may also be used in the reactive adhesive.

[0251] Also, reactive adhesives include dry laminating adhesives diluted with highly soluble organic solvents for dilution, solventless laminating adhesives containing almost no organic solvents for dilution, aqueous adhesives with water as the diluent, etc. Any of these adhesives can be peeled off by the separation and recovery method of the present invention. Specifically, highly soluble organic solvents for dilution include toluene, xylene, methylene chloride, tetrahydrofuran, methyl acetate, ethyl acetate, n-butyl acetate, acetone, methyl ethyl ketone (MEK), cyclohexanone, toluol, xylol, n-hexane, cyclohexane, etc. Among them, toluene, xylene, methylene chloride, tetrahydrofuran, methyl acetate, and ethyl acetate are particularly known as highly soluble organic solvents. Aqueous adhesives can use water and organic solvents having an affinity for water as diluents.

[0252] In the reactive adhesive, the blending ratio of the two-component type of the polyisocyanate composition and the polyol composition is the recommended blending ratio for commercial products. Generally, the equivalent ratio of isocyanate groups in the polyisocyanate composition to hydroxyl groups in the polyol composition [isocyanate group / hydroxyl group] is often in the range of 1.0 to 5.0. Of course, there may be cases where it is blended and used in other ranges.

[0253] The one-component adhesive of the reactive adhesive is used by applying the polyisocyanate composition alone to a film, and the isocyanate groups contained in the polyisocyanate composition react with moisture in the air and crosslink to be used as a laminating adhesive.

[0254] In a laminated film laminated with a reactive adhesive, the reactive adhesive is, for example, after mixing the reactive adhesive, applied to a resin base material, and then another resin base material is laminated on the coated surface, and then it is almost always cured and crosslinked through an aging process or the like.

[0255] Among them, the reactive adhesive preferably contains a resin or a low molecular compound having the acidic group. In a two-component reactive adhesive of a polyisocyanate composition and a polyol composition, it is preferable from the viewpoint of stability that the resin or the low molecular compound having the acidic group is blended in the polyol composition. The addition amount may be appropriately determined within a range that does not impair the adhesiveness and curability of the reactive adhesive, but is preferably in the range of 0.5 to 50% by weight, more preferably in the range of 1.0 to 30% by weight, based on the solid content of the polyol composition.

[0256] The coating amount of the adhesive is appropriately adjusted. In the case of a solvent-based adhesive, as an example, the solid content is 1 g / m 2 or more and 10 g / m 2 or less, preferably 2 g / m 2 or more and 5 g / m 2 or less. In the case of a solvent-free adhesive, the coating amount of the adhesive is, as an example, 1 g / m 2 or more and 5 g / m 2 or less, preferably 1 g / m 2 or more and 3 g / m 2 or less. The acid value of the resin or the low molecular compound having the acidic group is not particularly limited, but is preferably 150 mgKOH / g or more.

[0257] As described above, the alkaline solution used in this separation and recovery method is presumed to cause interfacial peeling by acting on the interface between the laminated film and the adhesive or the printing ink and significantly reducing the adhesive force. On the other hand, since the solubility of the alkaline solution itself is also high, the uncrosslinked printing layer also dissolves. Further, even when the printing layer itself is crosslinked, in the present invention, since interfacial peeling is caused, it is presumed that separation and recovery can be efficiently performed in a short time.

[0258] (Printing layer) The printing layer is a layer on which characters, figures, symbols, other desired patterns, etc. are printed. The printing method and printing ink are not particularly limited, and known printing methods and printing inks can be used. The printing layer is, for example, a printing ink printed using a gravure printing machine, a flexographic printing machine, an offset printing machine, an inkjet printing machine, etc., and using an organic solvent-based printing ink, an aqueous type or an active energy ray-curable ink. It may be a printing layer for multicolor printing using a plurality of ink types. In the present invention, by passing through Step 1 and Step 2, the printing layer can be peeled off regardless of the type of ink.

[0259] Printing inks to which a resin having an acidic group or a low molecular compound having an acidic group is added can also be preferably used. As the resin or low molecular compound having an acidic group, it can be easily mixed with the binder resin, organic solvent, etc. which are the main components of the printing ink, and any resin or low molecular compound having an acid value can be used without particular limitation.

[0260] As the resin or low molecular compound having an acidic group, the compounds described in the primer layer can be used.

[0261] Among others, the printing ink preferably contains a resin having an acidic group or a low molecular compound having an acidic group. The addition amount may be appropriately determined within a range that does not impair the printability of the printing ink, but is preferably in the range of 0.5 to 50% by weight, more preferably in the range of 1.0 to 30% by weight, based on the solid content of the printing ink.

[0262] The location where the printing layer is provided is not particularly limited. For example, the printing layer may be provided on the outermost layer of the laminated film, or may be between the resin film layer (F) and the adhesive layer (AD). When there is a printing layer between the resin film layer (F) and the adhesive layer (AD) (reverse printing), since the printing and the adhesive layer are more firmly bonded, it becomes more difficult to peel the printing layer, but the ink layer can be effectively peeled even in the configuration of reverse printing by the method of the present invention.

[0263] The printing layer can be a layer that displays any pattern, design, text, symbol, etc. for the purpose of imparting decoration or aesthetic sense, indicating contents, expiration date, and manufacturer or seller. The printing layer may be a solid printing layer without patterns, designs, text, symbols, etc. The method for forming the printing layer is not particularly limited and can be formed using known pigments and / or dyes. Preferably, the printing layer can be formed using printing ink containing pigments and / or dyes. The printing layer may have a single-layer structure or a multi-layer structure. The thickness of the printing layer is preferably 0.1 to 10 μm, more preferably 1 to 5 μm.

[0264] The printing layer may also contain pigment derivatives and / or resin-based dispersants as dispersants for colorants. These may be used alone, but it is preferable to use them in combination because the dispersion stability and stability over time are further improved.

[0265] For example, in the case of a plastic film structure of (F1) / INK / (AD) / (M) / (F2) or (F1) / INK / (AD) / (F2), since the printing layer exists between the layers constituting the plastic film and the printing layer and the adhesive layer are more firmly bonded, it is a plastic film structure that is difficult to separate into single layers and remove the printing layer. However, if in Step 1, a part of the F2 film is peeled off or the F2 is made into a crushed material that is easily peeled off to promote the peeling effect of the primer layer, then in Step 2, the remaining layer structure can be easily peeled off and the printing layer can be removed.

[0266] (Resin substrate A, resin substrate B) In the laminate structure, it is preferable to use films as the resin base material A and the resin base material B. The film material is not particularly limited, and examples thereof include polyethylene terephthalate (PET) film, polystyrene film, polyamide film, nylon film, polyacrylonitrile film, polyethylene film (OPE: biaxially stretched polyethylene film, LLDPE: low density polyethylene film, HDPE: high density polyethylene film), and polyolefin films such as polypropylene film (CPP: unstretched polypropylene film, OPP: biaxially stretched polypropylene film), polyvinyl alcohol film, ethylene-vinyl alcohol copolymer film, and cellophane.

[0267] Also, as these films, films laminated with an inorganic vapor deposition layer such as metal oxides such as silica and alumina can also be used. Specific examples include OPE films, OPP films, PET films, and nylon films having a silica vapor deposition layer, and OPE films, OPP films, PET films, and nylon films having an alumina vapor deposition layer.

[0268] When being aware of a single-material package, as the film, a film made of a thermoplastic resin mainly composed of an olefin resin can be used. As the resin base material A and / or the resin base material B, it is preferable to use a polyolefin resin, which may be a biaxially or uniaxially stretched film or an unstretched film. It is preferable that at least one of the resin base material A and the resin base material B is a biaxially or uniaxially stretched polyolefin film. Specifically, as the olefin resin, polyethylene such as low-density polyethylene, medium-density polyethylene, high-density polyethylene, linear (linear) low-density polyethylene, polypropylene, ethylene-propylene copolymer, α-olefin polymer, ethylene-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer, ethylene-acrylic acid copolymer, ethylene-methyl methacrylate copolymer, ethylene-ethyl acrylate copolymer, cyclic olefin resin, ionomer resin, polyolefin resins such as polymethylpentene; modified olefin resins obtained by modifying olefin resins with acrylic acid, methacrylic acid, maleic anhydride, fumaric acid and other unsaturated carboxylic acids can be mentioned.

[0269] The resin base material A and / or B may be a sealant film, a metal layer such as an aluminum foil, a non-stretched metal vapor deposition film, a stretched metal vapor deposition film, a stretched transparent vapor deposition film, etc. In the case of these vapor deposition films, the primer layer of the present invention may be provided on the vapor deposition surface or the non-vapor deposition surface. For example, in the above-described laminate configuration, the resin base material A and / or B and the resin film layer (F), when classified by the required role, function as a base film layer (F1) or a sealant layer (F2) that becomes a heat-sealing site when forming a packaging material.

[0270] For example, as the resin film serving as the base film layer (F1), examples include polyolefin films such as low-density polyethylene, high-density polyethylene, linear low-density polyethylene, OPP (biaxially oriented polypropylene), CPP (unoriented polypropylene), polyester films such as polyethylene terephthalate (PET), polybutylene terephthalate, polyamide films such as nylon 6, nylon 6,6, meta-xylene adipamide (N-MXD6), biodegradable films such as polylactic acid, polyacrylonitrile-based films, poly(meth)acrylic-based films, polystyrene-based films, polycarbonate-based films, ethylene-vinyl acetate copolymer saponified product (EVOH)-based films, polyvinyl alcohol-based films, polyvinylidene chloride, such as K-coated products, and films containing pigments in these. Transparent vapor-deposited films vapor-deposited with alumina or silica, etc. may also be used for these films.

[0271] Also, various surface treatments such as flame treatment, corona discharge treatment, or chemical treatments such as release primers may be performed on the surface of the film material.

[0272] As the flexible polymer film serving as the sealant layer (F2), polyolefin films such as polyethylene film, polypropylene film, ethylene-vinyl acetate copolymer, ionomer resin, EAA resin, EMAA resin, EMA resin, EMMA resin, and films of biodegradable resins are preferred. In general terms, CPP (unoriented polypropylene) film, VMCPP (aluminum-deposited unoriented polypropylene film), LLDPE (linear low-density polyethylene), LDPE (low-density polyethylene), HDPE (high-density polyethylene), VMLDPE (aluminum-deposited low-density polyethylene film), films containing these pigments, etc. may be mentioned. Various surface treatments such as flame treatment, corona discharge treatment, or chemical treatments such as release primers may be performed on the surface of the film.

[0273] The film thickness of the film is not particularly limited and may be appropriately selected within the range of 0.1 to 300 μm from the viewpoints of moldability and transparency. Preferably, it is in the range of 0.3 to 100 μm. If it is less than 0.1 μm, the strength will be insufficient, and if it exceeds 300 μm, the rigidity will become too high and processing may become difficult.

[0274] From the viewpoint of recycling, it is preferable that the layer structure is as simple as possible. However, from the viewpoint of the flowability of the packaging material, printing for displaying the contents, description, and name of the product of the packaging material is often necessary. The base material is also often printed.

[0275] From the viewpoint of reusing as a recycled base material, the base material preferably includes a polyolefin resin film such as polyethylene or polypropylene.

[0276] Examples of the metal foil layer (M) include foils of metals with excellent ductility such as gold, silver, copper, zinc, iron, lead, tin, and their alloys, steel, stainless steel, and aluminum. Examples of the paper layer include natural paper and synthetic paper. The first and second sealant layers may be formed of the same materials as the above-mentioned sealant layer.

[0277] Other layers may contain known additives and stabilizers, such as antistatic agents, non-reactive adhesive layers, easy-adhesion coating agents, plasticizers, lubricants, antioxidants, etc.

[0278] The resin base material A and the resin base material B are appropriately selected according to the usage mode of the laminate. For example, combinations of biaxially stretched base material / uniaxially stretched base material, biaxially stretched base material / non-stretched base material, uniaxially stretched base material / non-stretched base material, biaxially stretched base material / biaxially stretched base material, and uniaxially stretched base material / uniaxially stretched base material are preferable.

[0279] <Particle size distribution of the detached ink components> The median diameter (D50) of the detached ink component is preferably 1 μm or more. When the median diameter of the detached ink layer component is 1 μm or more, reattachment of the detached ink component to the substrate can be suppressed, and a colorless recycled material can be obtained. The median diameter of the detached ink component is preferably 5 μm or more, more preferably 10 μm or more, still more preferably 15 μm or more, and particularly preferably 20 μm or more.

[0280] The span value A of the detached ink component represents the particle size distribution width of the detached printing layer component. The larger the numerical value, the wider the particle size distribution width, and there is a tendency to contain fine printing layer components that are likely to reattach to the substrate. The span value A is preferably 10 or less, more preferably 8 or less, and even more preferably 5 or less. When the span value is 10 or less, reattachment of the detached printing layer can be suppressed, which is preferable.

[0281] In the present invention, the median diameter (D50) and the span value A of the printing layer component detached from the resin substrate are measured by a laser diffraction particle size distribution measuring device. The span value A is represented by the following formula.

[0282] A=(D90-D10) / D50 D10: Cumulative 10% diameter of the volume-based particle size distribution obtained by laser diffraction particle size distribution measurement of the detached ink component D90: Cumulative 90% diameter of the volume-based particle size distribution obtained by laser diffraction particle size distribution measurement of the detached printing layer component <Manufacturing method of molding material> By melt-kneading the crushed plastic film recovered by the above-described separation and recovery method, molding pellets can be produced. In the melt-kneading step, various additives and the like are added as necessary, and after mixing with a Henschel mixer, tumbler, disperser, etc., kneading and dispersion are performed using a kneader, roll mill, twin-screw extruder, single-screw extruder, rotor-type twin-screw kneader, etc. Thereby, a recycled resin which is a resin composition is obtained. The shape of the recycled resin is not particularly limited, and it may be in the form of pellets, powder, granules, or beads. It is preferable to use a twin-screw extruder in the melt-kneading step. The molding material can further contain a masterbatch. The masterbatch is not particularly limited as long as it has compatibility with the recycled resin. Generally, a material obtained by kneading a thermoplastic resin such as a polyethylene resin or polypropylene resin and a colorant can be used. The thermoplastic resin contained in the masterbatch may be used alone or in combination of two or more. The masterbatch may contain, within a range that does not inhibit the effects of the present invention, metal soaps of alkali metals, alkaline earth metals or zinc, hydrotalcite, nonionic surfactants, cationic surfactants, anionic surfactants, amphoteric surfactants, antistatic agents, flame retardants such as halogen-based, phosphorus-based or metal oxides, lubricants such as ethylene bisalkylamide, antioxidants, ultraviolet absorbers, fillers, peroxides.

[0283] <Molded article> By heat-molding the molding material obtained by the above-described production method, a molded body can be obtained. The heat-molding method is not particularly limited, and examples include injection molding, extrusion molding, blow molding, and compression molding. The molding material produced using the resin base material recovered by the separation and recovery method of the present invention is of high quality because the printed layer is detached and reattachment of the adhesive component is further suppressed, and it can be used in various fields such as home appliances, stationery, automotive parts, toys and sports goods, materials for medical and construction / building materials.

[0284] Additives that can be used in the manufacturing process of the recycled pellets obtained by the separation and recovery method of the present invention include at least one antioxidant selected from the group consisting of phenolic and phosphorus-based antioxidants, at least one lubricant selected from fatty acid amide-based, alkylene fatty acid amide-based, metal soap-based, and ester-based lubricants, hindered amine-based weather stabilizers, waxes with an acid value of 5 mg KOH / g or less, at least one antistatic agent selected from fatty acid sulfonates and fatty acid ester-based antistatic agents, and at least one peroxide selected from organic peroxides for modifying polypropylene, and the like. Examples of phenolic antioxidants include 2,6-di-t-butyl-p-cresol, butylated hydroxyanisole, 2,6-di-t-butyl-4-ethylphenol, 2,2'-methylene-bis-(4-methyl-6-t-butylphenol), 2,2'-methylene-bis-(4-ethyl-6-t-butylphenol), 4,4'-thiobis-(3-methyl-6-t-butylphenol), 4,4'-butylidene-bis-(3-methyl-6-t-butylphenol), 3,9-bis[{1,1-dimethyl-2-{β-(3-t-butyl-4-hydroxy-5-methylphenyl)propionyloxy}ethyl}2,4,8,10-tetraoxaspiro]5,5-undecane, 1,1,3-tris-(2-methyl-4-hydroxy-5-t-butylphenyl)butane, 1,3,5-trimethyl-2,4,6-tris(3,5-di-t-butyl-4-hydroxybenzyl)benzene, tetrakis-{methylene-3-(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate}methane, and bis{(3,3'-bis-4'-hydroxy-3'-t-butylphenyl)butyric acid}glucol ester. Examples of phosphorus-based antioxidants include triphenyl phosphite, diphenyl isodecyl phosphite, phenyl diisodecyl phosphite, 4,4'-butylidene-bis-(3-methyl-6-t-butylphenyl-di-tridecyl) phosphite, cyclic neopentanetetrayl bis(octadecyl phosphite), tris diphenyl phosphite, diisodecyl pentaerythritol diphosphite, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 10-(3,5-di-t-butyl-4-hydroxybenzyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 10-decyloxy-9,10-dihydro-9-oxa-10-phosphaphenanthrene, cyclic neopentanetetrayl bis(2,4-di-t-butylphenyl) phosphite, cyclic neopentanetetrayl bis(2,6-di-t-methylphenyl) phosphite, and 2,2-methylenebis(4,6-t-butylphenyl) octyl phosphite.

[0285] These antioxidants may be used alone or in combination of two or more. The addition amount of the antioxidant is preferably 0.01 to 1% by mass, more preferably 0.03 to 0.5% by mass, based on the mass of the molding material. When the addition amount is 0.01% by mass or more, it is preferable in terms of antioxidant property, and when it is 1% by mass or less, it is preferable in terms of processability.

[0286] Examples of fatty acid amide lubricants include aliphatic monocarboxylic acid amides such as lauric acid amide, palmitic acid amide, oleic acid amide, stearic acid amide, erucic acid amide, behenic acid amide, ricinoleic acid amide, and hydroxystearic acid amide; N-substituted aliphatic monocarboxylic acid amides such as N-oleoyl oleic acid amide, N-oleoyl stearic acid amide, and N-stearyl oleic acid amide; aliphatic biscarboxylic acid amides such as methylene bisstearic acid amide and ethylene bisstearic acid amide; N,N'-ethylene-bis-oleylamide, N,N'-ethylene bisstearic acid amide, and N,N'-methylene bisstearic acid amide.

[0287] Examples of metal soap lubricants include metal salts of higher fatty acids such as calcium stearate, magnesium stearate, barium stearate, zinc stearate, aluminum stearate, lithium stearate, calcium laurate, magnesium laurate, barium laurate, zinc laurate, aluminum laurate, and lithium laurate, as well as calcium hydroxystearate, magnesium hydroxystearate, barium hydroxystearate, zinc hydroxystearate, aluminum hydroxystearate, and lithium hydroxystearate. These lubricants may be used alone or in combination of two or more. The addition amount of the lubricant is preferably 0.01 to 1% by mass, more preferably 0.03 to 0.5% by mass, based on the mass of the molding material. An addition amount of 0.01% by mass or more is preferable in terms of activity, and an addition amount of 1% by mass or less is preferable in terms of processability.

[0288] Examples of hindered amine light stabilizers include dimethyl succinate-1-(2-hydroxyethyl)-4-hydroxy-2,2,6,6-tetramethylpiperidine polycondensate, poly[{6-(1,1,3,3-tetramethylbutyl)amino-1,3,5-triazine-2,4-diyl}{(2,2,6,6-tetramethyl-4-piperidyl)imino}hexamethylene{{2,2,6,6-tetramethyl-4-piperidyl)imino}], N,N'-bis(3-aminopropyl)ethylenediamine-2,4-bis[N-butyl-N-(1,2,2,6,6-pentamethyl-4-piperidyl)amino]-6-chloro-1,3,5-triazine condensate, bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate, and bis(1,2,2,6,6-pentamethyl-4-piperidyl) 2-(3,5-di-t-butyl-4-hydroxybenzyl)-2-n-butylmalonate.

[0289] Examples of waxes with an acid value of 5 mgKOH / g or less include natural waxes and synthetic waxes. Examples of natural waxes include plant waxes such as carnauba wax, candelilla wax, rice wax, and wood rosin, animal waxes such as beeswax, lanolin, and whale rosin, mineral waxes such as montan wax, ozokerite, and ceresin, and petroleum waxes such as paraffin wax, microcrystalline wax, and petrolatum. Synthetic waxes include semi-synthetic waxes and fully synthetic waxes. Semi-synthetic waxes are those obtained by modifying natural waxes or natural wax-like materials through chemical treatments such as esterification, amidation, and neutralization using acidic waxes. Examples of synthetic waxes include synthetic hydrocarbons such as polyethylene wax, polypropylene wax, and polystyrene wax.

[0290] These waxes with an acid value of 5 mg KOH / g or less may be used alone or in combination of two or more. The addition amount of the wax with an acid value of 5 mg KOH / g or less is preferably 0.5 to 50% by mass, more preferably 1 to 30% by mass based on the mass of the molding material. When the addition amount is 0.5% by mass or more, it is preferable in terms of fluidity adjustment, and when it is 50% by mass or less, it is preferable in terms of processability.

[0291] Examples of the anionic surfactant-based antistatic agent include carboxylates such as alkali metal salts of higher fatty acids, sulfate esters such as higher alcohol sulfate esters and higher alkyl ether sulfate esters, sulfonates such as alkylbenzene sulfonates, alkyl sulfonates, and paraffin sulfonates, and phosphate esters such as higher alcohol phosphate esters.

[0292] Examples of the nonionic surfactant include polyethylene glycol type nonionic surfactants such as higher alcohol ethylene oxide adducts, fatty acid ethylene oxide adducts, higher alkylamine ethylene oxide adducts, and polypropylene glycol ethylene oxide adducts, fatty acid esters of polyethylene oxide or glycerin, fatty acid esters of pentaerythritol, fatty acid esters of sorbitol or sorbitan, alkyl ethers of polyhydric alcohols, and polyhydric alcohol type nonionic surfactants such as aliphatic amides of alkanolamines.

[0293] These antistatic agents may be used alone or in combination of two or more. The addition amount of the antistatic agent is preferably 0.05 to 1% by mass, more preferably 0.1 to 0.5% by mass based on the mass of the molding material. When the addition amount is 0.05% by mass or more, it is preferable in terms of antistatic property, and when it is 1% by mass or less, it is preferable in terms of transparency and low bleeding property.

[0294] Examples of the organic peroxide include dicumyl peroxide, di(2-t-butylperoxyisopropyl)benzene, 2,5-dimethyl-2,5-bis(t-butylperoxy)hexane, 2,5-dimethyl-2,5-bis(t-butylperoxy)hexyne-3, and the like.

[0295] These organic peroxides may be used alone, in combination of two or more, or those diluted with an inorganic filler may also be used.

[0296] In order to modify the physical properties of the recycled pellets obtained by the method for producing a recycled plastic film, at least one of acid-modified polypropylene having a melting point of 130°C or higher and a thermoplastic elastomer, or polyethylene of a metallocene catalyst having a density of 0.94 or less may be melt-kneaded.

[0297] The modification of the physical properties of the recycled pellets means changing the physical properties of the raw plastic pellets of the plastic film before recycling. The purpose of modifying the physical properties is that when producing recycled pellets from a film using film-grade plastic pellets, various physical property values are often insufficient if the recycled pellets are directly used as molding materials.

[0298] The items for modifying the physical property values are various, such as tensile strength, flexural strength, elongation at break, tensile modulus, flexural modulus, yield point stress, impact value, etc., but are not limited thereto.

[0299] Examples of commercially available acid-modified thermoplastic elastomers include, for example, maleic anhydride-modified isoprene rubber such as LIR-403 manufactured by Kuraray Co., Ltd., modified isoprene rubber such as LIR-410 manufactured by Kuraray Co., Ltd., carboxy-modified nitrile rubber such as Clinac 110, 221, 231 manufactured by Polysar Co., maleic anhydride-modified polybutene such as Nisseki Polybutene manufactured by Nippon Oil Corporation, ethylene methacrylic acid copolymer such as Nuclel manufactured by Mitsui DuPont Polychemicals Co., ethylene methacrylic acid copolymer such as Yukalon manufactured by Mitsubishi Chemical Corporation, maleic anhydride-modified ethylene-propylene rubber such as Toughmer M (MA8510) manufactured by Mitsui Chemicals, Inc., maleic anhydride-modified ethylene-propylene rubber such as TX-1215 manufactured by Mitsui Chemicals, Inc., maleic anhydride-modified ethylene-butene rubber such as Toughmer M (MH7020) manufactured by Mitsui Chemicals, Inc., HPR series (maleic anhydride-modified EEA) manufactured by Mitsui DuPont Polychemicals Co., Bondine (maleic anhydride-modified EEA) manufactured by Atofina, Toughtec (maleic anhydride-modified SEBS, M1943) manufactured by Asahi Kasei Corporation, Clayton (maleic anhydride-modified SEBS, FG1901X) manufactured by Clayton Polymer Co., Toughprene (maleic anhydride-modified SBS, 912) manufactured by Asahi Kasei Corporation, Septon (maleic anhydride-modified SEPS) manufactured by Kuraray Co., Ltd., Lexparl (maleic anhydride-modified EEA, ET-182G, 224M, 234M) manufactured by Nippon Polyolefins Co., Ltd., Auroren (maleic anhydride-modified EEA, 200S, 250S) manufactured by Nippon Paper Chemicals Co., Ltd., and maleic anhydride-modified polyethylene and the like.

[0300] Particularly preferred examples of the acid-modified thermoplastic elastomer include maleic anhydride-modified styrene-ethylene-butadiene-styrene copolymer. Examples of commercially available acid-modified styrene-ethylene-butylene-styrene block copolymer include Toughtec M1911, Toughtec M1913, Toughtec M1943 manufactured by Asahi Kasei Chemicals Corporation, and the like.

[0301] Examples of commercially available non-acid-modified thermoplastic elastomers include ethylene methacrylic acid copolymers such as Nucrel manufactured by Mitsui DuPont Polychemicals Co., Ltd., ethylene methacrylic acid copolymers such as Yukalon manufactured by Mitsubishi Chemical Corporation, α-olefin copolymers such as Toughmer manufactured by Mitsui Chemicals, Inc., SEBS such as Tuftec manufactured by Asahi Kasei Corporation, SBS manufactured by Kuraray Co., Ltd. such as Toughprene manufactured by Asahi Kasei Corporation, SEPS such as Septon, and EEA such as Lex Pearl manufactured by Nippon Polyolefins Co., Ltd.

[0302] In the melt-kneading process, for example, when using a single-screw or twin-screw extruder, general melt-kneading conditions can be used. The kneading temperature is preferably 180 to 260 °C, more preferably 190 to 250 °C, and even more preferably 200 to 240 °C. To form an even better melt-kneading state, the temperature on the raw material inlet side is preferably about -50 to -100 °C lower than the central part, and the temperature on the outlet side is also preferably about -50 to -100 °C lower than the central part. More preferably, it is preferable to gradually increase the temperature with an inclination from the raw material inlet temperature to the central part, and gradually decrease the temperature with an inclination from the central part to the outlet. In particular, when the set temperature of the extruder near the outlet from the central part is lower than the melting point of the plastic introduced, increasing the die temperature by about 5 to 10 °C higher than the melting point of the plastic makes it easier to form plastic strands.

[0303] If the central part temperature is 180 °C or lower, it is difficult to perform melt-kneading, and if it is 260 °C or higher, the physical properties of the produced recycled pellets will significantly deteriorate. The temperature immediately after film input is preferably 20 to 100 °C so that the film melts immediately and does not cause bridging.

[0304] The screw rotation is preferably 50 to 500 rpm, more preferably 180 to 400 rpm, and even more preferably 100 to 300 rpm. If the rotation speed is too low, it is difficult to form uniform recycled pellets during melting, and if it is too high, the physical properties of the produced recycled pellets will significantly deteriorate due to the heat generated during kneading.

[0305] The speed of feeding the crushed plastic film into the extruder is preferably 5 to 100 kg / h, more preferably 5 to 50 kg / h, and even more preferably 5 to 30 kg / h. The higher the feeding speed, the higher the resin pressure in the extruder, and a better kneading state can be formed. Therefore, when kneading the recycled pellets with virgin pellets or when kneading the recycled pellets with modified resin, additives, etc., it is preferable to increase the resin pressure. The resin pressure is preferably 1 to 30 MPa, more preferably 1 to 25 MPa, and even more preferably 1 to 20 MPa.

[0306] The melt mass flow rate (MFR) of the recycled pellets is preferably 2 to 50 g / 10 min, more preferably 3 to 40 g / 10 min, and even more preferably 5 to 30 g / 10 min. By having the melt mass flow rate within the above range, a recycled molding material suitable for various moldings such as injection molding and extrusion molding can be provided.

[0307] (Discoloration evaluation of recycled pellets) The plastic crushed material that has sequentially undergone Steps 1 to 4 was extruded at 200 °C with a twin-screw extruder and pelletized to obtain recycled pellets. The recycled pellets were heated and pressed at 200 °C with a hot press to create a pressed plate with a thickness of 1 mm. The pressed plate was measured for the color values L * , a * , b * using a spectrophotometer (manufactured by X-rite, X-rite eXact). For the raw material pellets of the plastic film, a pressed plate with a thickness of 1 mm was similarly created through a heating and pressing process, and the color difference ΔE was obtained using the following calculation formula. ΔE = ((L * x - L * y) 2 + (a * x - a * y) 2 + (b * x―b * y) 2 ) 1 / 2 x: Raw material pellets y: Recycled pellets ΔE is preferably 30 or less, more preferably 20 or less, still more preferably 10 or less, and even more preferably 5 or less. The recycled pellets indicate that the ink has been decolorized by the cleaning process so that there is no color difference from the raw material pellets, and they have high utility value as recycled pellets. Also, since many molded articles are melt-kneaded with a masterbatch containing a colorant, if the desired color tone can be obtained, ΔE can be used sufficiently as long as it is 30 or less.

[0308] When the recycled pellets are in the form of a film with a thickness of about 100 μm, the total light transmittance is preferably 30% or more, more preferably 50% or more, and even more preferably 70% or more. The higher the total light transmittance, the more it indicates that the ink has been decolorized by the cleaning process, and the higher the utility value as recycled pellets.

[0309] (Mixing of recycled pellets and unused pellets) In the melt-kneading process of the plastic crushed material with the printing layer removed, it can also be mixed with unused plastic pellets at an arbitrary ratio according to the purpose. For example, the mixing ratio in terms of weight conversion between the recycled pellets and the unused pellets is 99.5:0.5 to 50:50. From the perspective of recyclability, it is preferable to make the ratio of the recycled pellets as high as possible.

[0310] As the unused plastic pellets to be used at this time, at least one type of polypropylene selected from block polymers, random polymers, and homopolymers can be used. Also, it can be selected from acid-modified polypropylene, thermoplastic elastomers, and polyethylene using a metallocene catalyst, and these can also be used by mixing at least one type or more.

[0311] An example of a specific embodiment will be described for the method for separating and recovering the laminate of the present invention.

[0312] (1) Step 1 of crushing the laminate First, the laminate is sequentially fed into a dry crusher or a wet crusher (hereinafter simply referred to as a crusher) to obtain plastic crushed materials. At this time, the laminate may be fed into the crusher after being cut into plastic pieces of a size of about 20 cm square or 30 cm square. By going through the cutting process, the crushing in the crusher in the next step can be performed more efficiently. Known crushers can be used for cutting, such as impact crushers like hammer crushers and rotary crushers, shredders, cutters, and the like. The size and shape of the plastic film to be fed are not particularly limited, but the maximum length of the plastic pieces is preferably 50 cm or less, preferably 30 cm or less, preferably 20 cm or less, and preferably 10 cm or less.

[0313] When using a screen or mesh in the dry crusher in Step 1, the hole diameter is preferably 30 mm or less, more preferably 20 mm or less, and even more preferably 10 mm or less. When using a 10 mm screen or mesh, the size of the crushed film pieces is 0.5 to 10 mm on the long side. Since the immersion in the cleaning liquid in Step 2 is more likely to obtain an effect as the size of the crushed film is smaller, in Step 1, the smaller the crushing size, the better.

[0314] When using a wet crusher in Step 1, the laminate obtained by cutting the laminated film roll into a size of about 20 cm square or 30 cm square is drawn into the crushing part by the suction of the crusher and crushed to about 1 to 20 mm or about 5 to 20 mm, and then pumped to the next step at 0.03 m 3 / min. At this time, due to the high shear force received when the fed laminate is crushed, at least a part of each layer constituting the laminate is easily separated into single layers. When a printing layer is provided on the laminate, the printing layer is also easily peeled off and removed from the film due to the high shear force during crushing, and it is preferable that at least a part of the printing layer is peeled off.

[0315] Even if the object to be crushed is not a laminated film roll but an individual film bag recovered from the market, it can be directly fed into the crusher as it is, in the recovered state.

[0316] When using a grinder as the crusher to crush the laminate into powder, it is preferable to use a laminated film roll cut into a size of about 5 mm square. The laminate crushed by the grinder is crushed to about 10 - 500 μm.

[0317] The number of times of the crushing process in the above step 1 may be once or divided into several times.

[0318] (2) Step 2 of immersing the laminate in a cleaning liquid In step 2, the plastic crushed material crushed in step 1 may be immersed in the cleaning liquid by being left standing, or may be immersed and, if necessary, stirred using a known stirring device such as a homodyne disperser or a wet crusher similar to that in step 1. If the crushed laminate is surface-printed, the printing layer on the surface is sufficiently swollen, and if it is a laminate including back printing, the printing layer and the adhesive layer are swollen to pure components.

[0319] The liquid temperature and stirring time when immersing in the cleaning liquid are not particularly limited and can be appropriately adjusted according to various conditions such as the material of the used cleaning liquid and the composition of the plastic film.

[0320] (3) Step 3 of separating the laminate by stirring the crushed laminate in the presence of a liquid After swelling the plastic crushed material of the laminate by steps 1 and 2, it is stirred in the presence of a liquid to separate the plastic film. In the liquid after separation, single-layer films of each separated layer, and residues such as adhesives, printing inks, and metal foils are in a state of floating, precipitating, or dissolving. After taking these out of the liquid, they are separately recovered.

[0321] As an example of a specific method, for instance, in flotation separation, plastics with a low specific gravity such as polyolefins like polypropylene and polyethylene (floaters), polyester with a higher specific gravity than polyolefins, condensation synthetic films such as nylon, or heavy materials such as metal foils are separated, the heavy materials are removed, and then, if necessary, the plastics recovered in the further washing and dehydration process are washed and dehydrated, and plastics with different specific gravities are separated by centrifugation. For example, it can be separated into a plastic separation containing vinyl chloride resin with a specific gravity of 1 or more that sinks in water, polyethylene terephthalate, etc., and a plastic separation containing olefin resins such as polyethylene and polypropylene that do not contain vinyl chloride resin. Further separation is possible by changing the specific gravity by appropriately changing the blending ratio of the liquid used in flotation separation, for example, water and organic solvents or salts.

[0322] After roughly separating and recovering by specific gravity separation, advanced separation may be performed using electrostatic separation or the like that utilizes the inherent charging characteristics of plastics.

[0323] As an example of a specific method, it is a method of separating by dropping a pre-charged plastic mixture between parallel plate electrodes to which a voltage is applied. Combinations of plastics with a small specific gravity difference that are difficult to separate by specific gravity separation can also be separated.

[0324] (4) Step 4 of finally washing the printing layer remaining on the washed plastic crushed film in the rinse liquid After washing the printing layer from the plastic crushed material by laminating the plastic film through Step 1, Step 2, and Step 3, it is stirred in the rinse liquid, and in Step 3, the printing layer on the film surface that could not be removed is removed, greatly improving the quality of the recycled pellets.

[0325] In Step 4, in addition to known stirring devices such as a homodisper, and a wet crusher similar to that in Step 1, a paint shaker, a paint conditioner, so-called mixers and kneaders can also be used. Further, devices other than these can also be used.

[0326] (5) Recovery and reuse of cleaning solution (Step 5) The water, cleaning solution, and rinse solution used in Steps 1 to 4 are supplied to any one or more recycling machines selected from a filter, a centrifuge, and an ultrafiltration machine to recover them, and after removing solids, they are reused. While performing the wet crushing step and the specific gravity separation step in Steps 1 to 4, on the other hand, the water, cleaning solution, or the reuse process of the cleaning solution can be continuously operated to separate solids from the water, cleaning solution, and rinse solution.

[0327] (6) Drying of plastic separations (Step 6) The recovered plastic crushed material separated and recovered in Step 3 or 4 is dried by any one or more methods selected from vacuum heating drying, hot air drying, and pressure compression drying to remove residual moisture. As a pretreatment for producing the recycled pellets described later, briquettes may be produced using a pressure compressor such as a squeezing dehydrator manufactured by Nippon Seam Co., Ltd., a pellet mill manufactured by Oike Iron Works Co., Ltd., Stella manufactured by Elcom Co., Ltd., or a briquette machine, after or during the drying of the film pieces that are the recovered material. When a plastic film is pulverized into a powder using a grinder as a wet crusher, the crushed material is pulverized to about 10 to 500 μm, and since the density of the crushed material is high, the pressure compression step can be omitted. The density varies depending on the material constituting the pulverized material, but a higher density is preferable because it is easier to handle when passing through a kneader. Specifically, in the dry state, 0.03 kg or more is preferable, 0.05 kg or more is more preferable, 0.2 kg or more is more preferable, and 0.3 kg or more is even more preferable.

[0328] (7) Production of recycled pellets (Step 7) The film pieces or briquettes dried in Process 6 are put into a single-screw and twin-screw extruder to produce recycled pellets. When directly putting the film pieces into the extruder without going through the pressurization and compression process, a phenomenon called bridging where the ink pieces clog the inlet is likely to occur. To avoid bridging, the film pieces may be pressurized in the feeder section or pushed in with air. Also, to avoid bridging, the screws of the extruder body may use a twin-screw that rotates in opposite directions to each other, or may be pushed in using a side feeder. The kneader conditions are not particularly limited, but in order not to significantly deteriorate the resin performance before recycling, it is preferably operated at 180 to 260 °C.

Example

[0329] Hereinafter, the content and effects of the present invention will be described in more detail with examples, but the present invention is not limited to these examples. Also, “%” in the compositions of the following examples means “mass %”.

[0330] First, the primer compositions used in the examples and comparative examples were adjusted as follows.

[0331] [Adjustment of Primer Composition] Primer Composition 1 is as follows.

[0332] 100 parts of Urethane Resin 1 was diluted to a solid content of 10% with isopropyl alcohol (IPA) to obtain a primer-forming composition composed of an aqueous urethane resin composition.

[0333] <Urethane Resin 1> Urethane Resin 1 was synthesized as follows.

[0334] Into a four-necked flask equipped with a stirrer, thermometer, reflux condenser, and nitrogen gas inlet tube, 0.74 g of polyol a, 0.20 g of isophorone diisocyanate, and 0.06 g of 2,2'-dimethylolpropionic acid were charged in a ratio, and reacted at 75 °C for 8 hours under a nitrogen stream to obtain Urethane Resin 1.

[0335] Polyol a was prepared by mixing terephthalic acid (TPA) at 0.32 g, isophthalic acid (IPA) at 0.32 g, ethylene glycol (EG) at 0.13 g, and diethylene glycol (DEG) at 0.23 g and reacting them to produce an aromatic polyester polyol.

[0336] The composition and physical properties of polyol a are shown in Table 1 below.

[0337] The composition and physical properties of urethane resin 1 are shown in Table 2 below.

[0338]

Table 1

[0339]

Table 2

[0340] <Aromatic ring concentration (mmol / g) derived from the raw material monomer of aromatic dicarboxylic acid (a1-1)> Calculate the number of moles of aromatic rings contained in 1 g of urethane resin 1. It can be calculated based on the raw materials used in the synthesis of the aromatic polyester polyol and their blending amounts.

[0341] The mass of the raw material monomer of aromatic dicarboxylic acid (a1-1) contained in 1 g of urethane resin is obtained by dividing it by the molecular weight of the raw material monomer of aromatic dicarboxylic acid (a1-1).

[0342] <Ester bond group concentration (mmol / g)> Calculate the number of moles of ester bond groups contained in 1 g of urethane resin 1. It can be calculated based on the raw materials used in the synthesis of the aromatic polyester polyol and their blending amounts.

[0343] First, calculate the ester bond group concentration in 1 g of aromatic polyester polyol (a1) by the following formula (I). This formula (I) is a formula considering dehydration due to ester formation.

[0344]

Number

[0345] (In formula (I), a represents the number of moles of carboxylic acid in 1 g of aromatic polyester polyol (a1).) When the ester bond group concentration in 1 g of aromatic polyester polyol (a1) is determined, next, the product of the ester bond group concentration in 1 g of aromatic polyester polyol (a1) and the ratio of aromatic polyester polyol (a1) in 1 g of urethane resin is determined to calculate the ester bond group concentration in 1 g of urethane resin.

[0346] <Acid value (mgKOH / g)> The COOH groups contained in 1 g of urethane resin are determined by the number of mg of KOH required when titrated by the potassium hydroxide method.

[0347] <Urethane + urea functional group concentration (mmol / g)> The mass of the raw material monomer of polyisocyanate (a2) contained in 1 g of urethane resin is obtained by dividing by the NCO equivalent weight of the raw material monomer of polyisocyanate (a2).

[0348] <Weight average molecular weight> The weight average molecular weight is measured by gel permeation chromatography (GPC).

[0349] <Glass transition temperature (°C)> The glass transition temperature is measured by a differential scanning calorimeter.

[0350] <Polyol hydroxyl value> It is measured in accordance with the method described in JIS K1557-1.

[0351] The aromatic ring concentration described in Table 1 was determined as follows.

[0352] First, the aromatic ring concentration in 1 g of polyol a is calculated. ·Determine the mass ratio of the raw material monomer of the aromatic dicarboxylic acid (a1-1) containing an aromatic ring / the molecular weight of the monomer (when there are multiple raw material monomers of the aromatic dicarboxylic acid (a1-1), find the sum). ·{0.32 (terephthalic acid content of polyol a) / 166 (molecular weight of terephthalic acid) + 0.32 (isophthalic acid content of polyol a) / 166 (molecular weight of isophthalic acid)} × 1000 = 3.8 mmol / g Next, find the product of the aromatic ring concentration in 1 g of the aromatic polyester polyol (a1) and the ratio of the aromatic polyester polyol (a1) in 1 g of the urethane resin, and calculate the aromatic ring concentration in 1 g of the urethane resin. ·3.84 (aromatic ring concentration of polyol a) × 0.74 (content of polyol a in urethane resin 1) = 2.8 mmol / g The ester bond group concentration described in Table 1 was determined as follows.

[0353] Taking urethane resin 1 as an example for explanation.

[0354] First, calculate the ester bond group concentration in 1 g of polyol a.

[0355] If the number of moles of carboxylic acid in 1 g of the aromatic polyester polyol (a1) is a, then a is determined as follows. ·a = {0.32 (terephthalic acid content of polyol a) / 166 (molecular weight of terephthalic acid) + 0.32 (isophthalic acid content of polyol a) / 166 (molecular weight of isophthalic acid)} × 2 (two carboxylic acids are contained in the raw material monomer of the aromatic dicarboxylic acid (a1-1)) = 0.00771 Next, substitute the obtained a into the above formula (I). ·{a / (1 - a × 18 (amount of water to be dehydrated))} × 1000 = 8.9 mmol / g Next, find the product of the ester bond group concentration in 1 g of the aromatic polyester polyol (a1) and the ratio of the aromatic polyester polyol (a1) in 1 g of the urethane resin, and calculate the ester bond group concentration in 1 g of the urethane resin. 8.9 (ester bond group concentration of polyol a) × 0.74 (polyol a content in urethane resin 1) = 6.6 mmol / g The urethane + urea functional group concentrations shown in Table 2 were determined as follows. 0.2 (Isophorone diisocyanate content in urethane resin 1) ÷ 111.15 (NCO equivalent weight of isophorone diisocyanate) = 1.8 mmol / g Here, the NCO equivalent weight of isophorone diisocyanate is calculated by dividing the molecular weight of isophorone diisocyanate by 2, i.e., 222.3÷2=111.15.

[0356] The laminates used in the examples and comparative examples were prepared as follows.

[0357] (LAM1) PE / printed layer (white) / adhesive layer / detachable primer layer / PE The prepared primer-forming composition was solidly applied to a polyethylene film (25 μm, PE3K-H, manufactured by Futamura Chemical Co., Ltd.) using a gravure printing machine and dried at 90° C. for 1 minute to form a removable primer layer.

[0358] A urethane-based laminating ink (Finart R794 white S, manufactured by DIC Corporation) was adjusted to 15 seconds (25°C) using a Zahn Cup #3 manufactured by Rigo Co., Ltd., and printed solidly on a polyethylene film (PE3K-H, 25 μm, manufactured by Futamura Chemical Co., Ltd.) using a gravure printing press equipped with a gravure plate with a plate depth of 43 μm. The film was then passed through an oven at 70°C to dry and harden it, forming a printed layer.

[0359] Next, a urethane-based two-component curing type laminating adhesive was applied onto the printed layer, and the printed layer was bonded to the surface of the polyethylene film on which the above-mentioned removable primer layer was formed. Aging was performed for 5 days at 40°C to obtain LAM1 of PE / printed layer (white) / adhesive layer / detachable primer layer / PE. The following urethane-based two-component curing type laminating adhesive was used.

[0360] (LX510 / KW75) A mixture of 9 parts of DIC Corporation's DICDRY (registered trademark) LX-510 and 1 part of KW-75 was diluted with ethyl acetate, and the coating amount (solid content) was 4 g / m 2 using an RDS Meyer coating bar. After applying the adhesive, the solvent was dried with a dryer before laminating with a polyethylene film on which a release primer layer had been formed.

[0361] (LAM2) PE / Release primer layer / Printing layer (white) / Adhesive layer / Release primer layer / PE The adjusted primer-forming composition was applied in a solid state to a polyethylene film (PE3K-H, 25 μm, manufactured by Futamura Chemical Co., Ltd.) using a gravure printing press, dried at 90 °C for 1 minute to form a release primer layer. Next, a urethane-based laminating ink (DIC Corporation's Finart R794 white S) was adjusted to 15 seconds (25 °C) using a Rheonard cup #3 manufactured by Rheonard Co., Ltd., and printed in a solid state on the release primer layer forming surface of the polyethylene film on which the above release primer layer had been formed using a gravure printing press equipped with a gravure plate with a plate depth of 43 μm, and dried or cured by passing through an oven at 70 °C to form a printing layer.

[0362] Next, a urethane-based two-component curable laminating adhesive was applied on the printing layer and laminated with the release primer layer forming surface of the polyethylene film on which the above release primer layer had been formed. It was aged at 40 °C for 5 days to obtain LAM2 of PE / Release primer layer / Printing layer (white) / Adhesive layer / Release primer layer / PE. The same urethane-based two-component curable laminating adhesive as LAM1 was used.

[0363] (LAM3) PE / Releaseable primer layer / Printing layer (white) / Adhesive layer / PE The adjusted primer-forming composition was applied in a solid state to a polyethylene film (PE3K-H manufactured by Futamura Chemical Co., Ltd., 25 μm) using a gravure printing machine, dried at 90°C for 1 minute, and a release primer layer was formed. Next, a urethane-based laminating ink (FINAT R794 White S manufactured by DIC Corporation) was adjusted with a Zahn cup #3 manufactured by Liasei Co., Ltd. for 15 seconds (25°C), and was printed in a solid state on the release primer layer formation surface of the polyethylene film on which the above-mentioned release primer layer was formed using a gravure printing machine equipped with a gravure plate with a plate depth of 43 μm, and dried or cured by passing through an oven at 70°C to form a printed layer.

[0364] Next, a urethane-based two-component curable laminating adhesive was applied onto the printed layer and laminated with a polyethylene film (PE3K-H manufactured by Futamura Chemical Co., Ltd., 25 μm). It was aged at 40°C for 5 days to obtain LAM3 of PE / release primer layer / printed layer (white) / adhesive layer / PE. The following urethane-based two-component curable laminating adhesive was used.

[0365] (LX510 / KW75) A mixture of 9 parts of DICDRY (registered trademark) LX-510 and 1 part of KW-75, both manufactured by DIC Corporation, was diluted with ethyl acetate and applied with a RDS Mayer coating bar with an application amount (solid content) of 4 g / m 2 and the solvent was dried with a dryer after applying the adhesive and before laminating with the polyethylene film.

[0366] (LAM4) PE / printed layer (white) / adhesive layer / PE A urethane-based laminating ink (FINAT R794 White S manufactured by DIC Corporation) was adjusted with a Zahn cup #3 manufactured by Liasei Co., Ltd. for 15 seconds (25°C), and was printed in a solid state on a polyethylene film (PE3K-H manufactured by Futamura Chemical Co., Ltd., 25 μm) using a gravure printing machine equipped with a gravure plate with a plate depth of 43 μm, and dried or cured by passing through an oven at 70°C to form a printed layer.

[0367] Next, a urethane-based two-component curable laminate adhesive was applied onto the printing layer and laminated with a polyethylene film (PE3K-H manufactured by Futamura Chemical Co., Ltd., 25 μm). It was aged at 40°C for 5 days to obtain LAM4 of PE / printing layer (white) / adhesive layer / PE. The same urethane-based two-component curable laminate adhesive as LAM3 was used.

[0368]

Table 3

[0369] (Process 1: Crushing process) LAM1 to 4 were put into a dry crusher equipped with a screen with a hole diameter of 10 mm and crushed until the short side direction of the crushed film was about 5 to 10 mm and the long side direction was about 10 to 20 mm.

[0370] (Process 2: Immersion process) PRO_A: It was gently immersed in the cleaning solution at 40°C for 16 hours. PRO_B: It was put into the cleaning solution at 75°C for 120 minutes and stirred at 500 rpm using a three-one motor.

[0371] (Cleaning solution) Water, the surfactant shown in Table 2, and 2% by weight of sodium hydroxide were mixed to prepare the cleaning solution shown in Table 3. For the cleaning solution composition, the ingredients were added vertically, and water was added so that the total would reach 100% for any amount less than 100%.

[0372]

Table 4

[0373] Note that DSK NL-Dash 403 is a polyalkylalkylene lauryl ether in which the carbon number of R1 in the general formula (1) described above is 12, and its HLB value is 3.0.

[0374] In addition, Nonion E215 is a nonionic surfactant with an HLB value of 12.5 or more represented by the general formula (1).

[0375] Also, M2-100R is a cationic surfactant represented by the aforementioned general formula (1).

[0376]

Table 5

[0377] (Step 3 Stirring and Separation Step) pro_a: Using a vibration mill manufactured by Chuo Kakoki Co., Ltd., 50 g of the plastic film obtained in Step 2 was used, and in a 4 L container with 1 L of water, a rod with a diameter of 19 mm was used as the media, and it was operated for 1 minute at a filling rate of 30%. pro_b: Using a MightyBlender manufactured by Osaka Gas Chemical Co., Ltd., 10 g of the plastic film obtained in Step 2 was used, and in a 1 L container with 100 mL of water, it was operated at 19,000 rpm for 1 minute. pro_c: Using a paint conditioner, 10 g of the plastic film obtained in Step 2 was used, and in a 300 mL container with 100 mL of water, zirconia balls with a diameter of 4.8 mm were used as the media, and it was operated for 1 minute at a filling rate of 30%. pro_d: Using a cleaning crusher PFS-40 (grid mesh size = 5 mmΦ) manufactured by Nippon Seam Co., Ltd., 10 g of the plastic film obtained in Step 2 was used, and it was operated at a rotational speed of 600 rpm while supplying water at 15 L / min.

[0378] <Results> Regarding the laminate obtained above, plastic film pieces (plastic crushed materials) that had sequentially passed through Steps 1 to 3 were taken out, dried, and then the peel area (%) of the two laminated polyethylene films was examined. According to the peel area (%), ratings were given as follows. The higher the score, the better the peelability.

[0379] 1 point (peel area less than 10%) 2 points (peel area 10% or more and less than 50%) 3 points (peeling area: 50% or more to less than 100%) 4 points (peeling area: 100%) The results are shown in the following table.

[0380] Also, the following table describes the "way of peeling the printing layer / adhesive layer" for the plastic film pieces (plastic crushed materials) that have sequentially gone through Steps 1 to 3.

[0381] Film-like (the printing layer / adhesive layer peeled off in a lump with a certain degree of film state) Powdery (the printing layer / adhesive layer peeled off in powder form) - (the printing layer / adhesive layer remained without peeling off from the film)

[0382] [Table 6]

[0383] [Table 7]

[0384] [Table 8]

[0385] From these results, it was found that the examples of the present invention have an excellent effect on the peeling of the plastic film. Also, a configuration having a primer layer between the film (resin base material) and the printing layer like LAM4 was able to peel the printing layer existing between the plastic film layers. Furthermore, it was found that by using a surfactant-containing cleaning liquid with an HLB value of less than 12.5 as the cleaning liquid, the printing layer / adhesive layer can be peeled off in a film-like state.

[0386] In Examples 10 and 11, since the laminate used has a configuration in which the primer layer is provided only on one side of the plastic film, only the plastic film in contact with the primer layer was peeled off, and excellent peelability of the plastic film was confirmed.

Claims

1. A method for separating and recovering a laminate having at least an adhesive layer and a release primer layer between a resin substrate A and a resin substrate B, comprising: Step 1 of crushing the laminate; Step 2 of immersing the laminate in a cleaning liquid containing an inorganic base; Step 3 of separating the crushed laminate into single-layer plastic crushed materials by stirring the crushed laminate in the presence of a liquid A method for separating and recovering a laminate having the above steps.

2. The adhesive layer is selected from an ether-based adhesive or an ester-based adhesive The method for separating and recovering a laminate according to Claim 1.

3. There is further a printing layer between the resin substrate A and the resin substrate B The method for separating and recovering a laminate according to Claim 1 or 2.

4. One surface of the release primer layer is in contact with the adhesive layer, and the other surface is in contact with the resin substrate A or the resin substrate B The method for separating and recovering a laminate according to Claim 1 or 2.

5. The adhesive layer has a printing layer on the surface opposite to the surface on which the release primer layer is provided, The printing layer has a second release primer layer on the surface opposite to the surface on which the adhesive layer is provided The method for separating and recovering a laminate according to Claim 1 or 2.

6. The adhesive layer has a printing layer on the surface opposite to the surface on which the release primer layer is provided, The printing layer does not have a second release primer layer on the surface opposite to the surface on which the adhesive layer is provided The method for separating and recovering a laminate according to Claim 1 or 2.

7. In Step 2, The water content in the cleaning liquid is 60% by mass or more, It contains a nonionic surfactant, The nonionic surfactant contains at least one selected from polyoxyalkylene alkyl ether, polyoxyethylene alkyl ether, and / or polyoxyethylene alkyl phenyl ether The method for separating and recovering a laminate according to Claim 1 or 2.

8. By wet crushing treatment of crushing the crushed laminate in the presence of a liquid while stirring, Removing the adhesive layer and the release primer layer from the crushed laminate The method for separating and recovering a laminate according to Claim 1 or 2.

9. In Step 3, the average volume of the plastic crushed materials obtained by the wet crushing treatment is 0.99 times or less of the average volume of the crushed laminate in Step 1 The method for separating and recovering a laminate according to Claim 8.

10. The resin substrate A and / or the resin substrate B is a polyolefin resin Method for separating and recovering the laminate according to claim 1 or 2.

11. Method for producing recycled plastic pellets, which comprises recovering plastic crushed materials separated by the method of claim 1 or 2 for each single layer, melting the recovered materials, and then molding the melted materials by a molding machine.

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