Method for separating and recovering laminated materials

Abstract

The present invention aims to provide a method for separating and recovering laminates that can sufficiently separate laminates containing adhesive layers and remove ink. [Solution] A method for separating and recovering at least a base layer from a laminate comprising two or more layers including a base layer and at least one layer selected from the group consisting of a printing layer (A), an adhesive resin layer (B), and a sealant layer (C), comprising the steps of (1), (2), (3), (4), and (5), wherein in step (2), the total volume of the laminate and release agent is 1 m³ 3 The stirring power value per unit (the power used for stirring minus the power used for dry running) is 10 W / m². 3 The above describes the method for separating and recovering the laminated material.

Description

[Technical Field]

[0001] The present invention relates to a method for separating and recovering laminates. [Background technology]

[0002] Laminated plastic films have been widely used as packaging materials for food products, daily necessities, pharmaceuticals, industrial components, and more. To meet the required performance characteristics such as durability, long-term storage, and airtightness, plastic film packaging materials have been made highly functional by combining the functions of each layer through multilayering. For example, aromatic polyamide resin layers, ethylene-vinyl acetate copolymer saponified (EVOH) layers, and inorganic vapor-deposited film layers have been used from the perspective of gas barrier properties that are effective in reducing food waste; aliphatic polyamide resin layers and polyester resin layers have been used from the perspective of mechanical strength of the packaging material; and polyethylene resin layers with high heat sealability have been used from the perspective of airtightness. Furthermore, high functionality has been achieved by laminating multiple types of films with various functions using adhesive layers. On the other hand, in recent years, environmental problems have become more serious, and the reduction of environmental impact through the recycling of plastic films is being considered.

[0003] To recycle laminates (laminated films) made of plastic film, it is necessary to peel off and separate each layer, and technological development has been carried out for this purpose. For example, Patent Document 1 discloses a technology that uses a laminate that is suitable for use in industrial materials, agricultural materials and packaging materials, and has excellent recyclability as it can be separated and recovered. This laminate is characterized by having at least one layer that can be partially or completely dissolved by acid or alkaline aqueous solution treatment, and at least one polymer layer that can be recovered.

[0004] Patent Document 2 describes a method for efficiently separating and recovering plastics, aluminum, etc., from a mixed plastic, in which "ethylene glycol (EG) is used in a wet specific gravity differential separation liquid that does not dissolve the mixed plastic, and PO (polyolefin resin), PS (polystyrene), ABS (acrylonitrile-butadiene-styrene copolymer), PET (polyethylene terephthalate), PVC (polyvinyl chloride), and aluminum are separated at a heating temperature near their melting point (120~170°C), and then PVC, aluminum, etc. are separated by sedimentation with a water and ethylene glycol mixture. The EG is then separated and recovered. The technology disclosed states that any shortage is recycled and reused from the PET depolymerization process. Furthermore, PET, PVC, aluminum, etc. are depolymerized by heating at atmospheric pressure (170°C to 186°C) in EG and NaOH to produce terephthalate and EG. PVC is dechlorinated and hydrogen chloride becomes NaCl. Meanwhile, solid materials such as PO, PVC, and aluminum are dissolved in a solvent such as xylene, and the aluminum and solid materials are recovered by drying off the adhering solvent. Furthermore, the mixed solution of PO, terephthalate, and NaOH is heated and vacuum evaporated to separate the solvent, which is then recycled and reused, and washed with water to separate it into PO, terephthalate, and NaOH.

[0005] Patent Document 3 discloses a method for recycling a multilayer film containing a plastic layer mainly composed of polyester (PET), polypropylene (PP), and polyethylene (PE), and an aluminum layer. Furthermore, it discloses a method for separating and recycling valuable components from multilayer plastic films for packaging that are discarded without being recycled, using a selective dissolution step of aluminum, a specific gravity difference separation step, a selective extrusion step based on a melting point difference, and a selective dissolution step with an organic solvent. This method involves selectively dissolving the aluminum in the waste multilayer film to induce layer separation, separating it into a mixed layer of PP and PE and a PET layer using a specific gravity difference, and further separating the main components of the multilayer film into PET, a mixed layer of PP and PE, and an aluminum component by extracting the PP and PE contained in the PET layer using an organic solvent at 100°C or its boiling point to increase the purity of the PET separated by the specific gravity difference.

[0006] Patent Document 4 discloses a technique for separating a plastic laminate having two or more layers by crushing it in water or a detergent. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2001-58372 [Patent Document 2] Japanese Patent Publication No. 2006-110531 [Patent Document 3] Japanese Patent Publication No. 2006-205160 [Patent Document 4] International Publication No. 2021 / 230033 [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] However, Patent Documents 1-3 do not disclose methods for recycling molded articles (laminated articles, laminated films) containing adhesive layers, nor do they disclose techniques for dissolving adhesive layers. Furthermore, while Patent Document 4 can separate the printed layer of a plastic laminate, it does not adequately remove the ink components dissolved in the separation solution, which may lead to discoloration due to the ink when the laminate is reused.

[0009] This invention has been made in view of the above circumstances, and its objective is to provide a method for separating and recovering laminates that can sufficiently separate the laminate containing the adhesive layer and remove the ink. [Means for solving the problem]

[0010] The inventors of the present invention conducted diligent studies to achieve the above objectives and found that the above-mentioned problems could be solved by having a specific process during the separation and recovery of the laminate, thus completing the present invention as described below.

[0011] [1] Substrate layer and A method for separating and recovering at least a base material layer from a laminate composed of two or more layers including at least one layer selected from the group consisting of a printing layer (A), an adhesive resin layer (B), and a sealant layer (C). It has the following steps (1), (2), (3), (4), and (5). (2) In the step, the stirring power value per 1 m 3 of the total volume of the laminate and the release agent (P) (the value obtained by subtracting the power required for idling from the power applied for stirring) is 10 W / m 3 or more. A method for separating and recovering a laminate; (1) A step of pulverizing the laminate (2) A step of peeling each layer of the laminate using an alkaline release agent (P) containing a polar solvent (3) A step of washing the peeled layer pieces using a rinsing agent (Q) containing a polar solvent and / or a surfactant (4) A step of centrifuging the release agent and / or the rinsing agent remaining on the layer pieces peeled in the previous step using a separator (5) A step of sorting the layer pieces peeled in the previous step. [2] The method for separating and recovering a laminate according to [1], wherein the method for separating and recovering a laminate has the steps (1), (2), (4), (3), (4), and (5) in this order, and the temperature of the release agent (P) in the step (2) is 70°C or higher and 100°C or lower. [3] (3) In the step, the stirring power value per 1 m 3 of the total volume of the peeled layer pieces and the rinsing agent (Q) (the value obtained by subtracting the power required for idling from the power applied for stirring) is 10 W / m 3 or more. The method for separating and recovering a laminate according to [1] or [2]. [4] (2) In the step, the mass ratio of the laminate to the total mass of 100% by mass of the release agent (P) and the laminate is 3% by mass or more and 20% by mass or less. The method for separating and recovering a laminate according to any one of [1] to [3]. [5] The laminate includes a printing layer (A). The method for separating and recovering the laminate according to any one of [1] to [4], wherein the printing layer (A) contains at least one resin selected from the group consisting of an acrylic resin, a polyurethane resin, a polyester resin, and a polyamide resin, and a pigment. [6] The laminate includes an adhesive resin layer (B), The method for separating and recovering the laminate according to any one of [1] to [5], wherein the adhesive resin layer (B) contains at least one selected from the group consisting of a urethane resin, an ester resin, an epoxy resin, and an acrylic resin. [7] The method for separating and recovering the laminate according to any one of [1] to [6], wherein the base material layer contains at least one selected from the group consisting of a polyester resin, a polyolefin resin, and a polyamide resin. [8] The method for separating and recovering the laminate according to any one of [1] to [7], wherein the base material layer contains a polyamide resin. [9] The method for separating and recovering the laminate according to any one of [1] to [8], wherein the absolute value Δb* of the difference between the b* value of the base material layer separated and recovered by the method for separating and recovering the laminate and the b* value of the base material layer before the peeling treatment is 2.5 or less.

[10] The laminate includes a sealant layer (C), The method for separating and recovering the laminate according to any one of [1] to [9], wherein the sealant layer (C) contains a polyolefin resin.

[11] The method for separating and recovering the laminate according to any one of [1] to

[10] , wherein the sealant layer (C) contains a polyethylene resin.

[12] The method for separating and recovering the laminate includes separating and recovering the sealant layer (C), The method for separating and recovering the laminate according to any one of [1] to

[11] , wherein the absolute value Δa* of the difference between the a* value of the sealant layer (C) separated and recovered by the method for separating and recovering the laminate and the a* value of the sealant layer (C) before the peeling treatment is less than 2.5. [Effects of the Invention]

[0012] According to the method of the present invention, it is possible to provide a method for separating and recovering a laminate that can sufficiently separate the laminate containing an adhesive layer and remove the ink. [Modes for carrying out the invention]

[0013] <Separation and Recovery Method> This embodiment relates to a method for separating and recovering at least a base layer from a laminate consisting of two or more layers, including a base layer and at least one layer selected from the group consisting of a printing layer (A), an adhesive resin layer (B), and a sealant layer (C). The laminate separation and recovery method of this embodiment has the following steps (1), (2), (3), (4), and (5), and in step (2), the total volume of the laminate and release agent (P) is 1 m³ 3 The stirring power value per unit (the power used for stirring minus the power used for dry running) is 10 W / m². 3 That's all. (1) Process of crushing the laminate (2) A step of peeling off each layer of the laminate using an alkaline release agent (P) containing a polar solvent. (3) A step of washing the peeled layer with a rinse agent (Q) containing a polar solvent and / or a surfactant. (4) A step in which the release agent and / or rinsing agent remaining on the layer fragments removed in the previous step are centrifuged using a separator. (5) A step of separating the layer fragments that were peeled off in the previous step.

[0014] In this embodiment, by separating a laminate consisting of two or more layers and providing the above-described predetermined step when recovering at least the base layer, the adhesive resin layer (B) can be dissolved, allowing the layers constituting the laminate to be peeled off, and furthermore, the ink originating from the printed layer (A) can be sufficiently removed. As a result, at least the base layer can be recovered. In addition, if the laminate has a sealant layer, the sealant layer can also be recovered in addition to the base layer. Furthermore, there is little residual ink in the recovered base layer and / or sealant layer, and as a result, the color difference between the base layer and / or sealant layer before and after separation and recovery is suppressed. Thus, this embodiment relates to a recycling method that can separate and recover a laminate consisting of two or more layers, and the recovered base layer and / or sealant layer shows suppressed discoloration.

[0015] <Base material layer> The laminate used in this embodiment has a base layer. The base layer is a layer made of a resin film and preferably contains at least one selected from the group consisting of polyester resins, polyolefin resins, and polyamide resins. In particular, the base layer preferably contains a polyamide resin.

[0016] When a polyamide resin is used as the base layer, an adhesive layer may be provided when forming a laminate. In such cases, conventional techniques have made it impossible to separate the polyamide resin layer from the laminate. For example, when techniques such as those disclosed in Patent Documents 1 to 3 are applied to a laminate containing a polyamide resin layer, the polyamide resin is hydrolyzed by processes using acids and alkalis or processes using organic solvents at high temperatures of around 100°C to 186°C, resulting in oxidative degradation and making it difficult to reuse the polyamide resin layer. On the other hand, in this embodiment, by having a specific process during the separation and recovery of the laminate, it is possible to separate the laminate containing the adhesive layer, making it possible to reuse the polyamide resin layer.

[0017] The resin content in the base layer is preferably 50% by mass or more, more preferably 60% by mass or more, even more preferably 70% by mass or more, even more preferably 80% by mass or more, and particularly preferably 90% by mass or more, based on the total mass of the base layer. The resin content in the base layer may also be 100% by mass.

[0018] The thickness of the base material layer of the present invention is not particularly limited, but from the viewpoint of mechanical properties, processability, transparency, and handling when used as a packaging material, etc., 5 to 500 μm is preferred, 10 to 300 μm is more preferred, and 12 to 250 μm is even more preferred. If the total thickness is within the above range, the mechanical properties as a laminate (film) are good, and it becomes an excellent film as a packaging material. If the thickness of the base material layer is thinner than the above range, not only are the mechanical properties inferior, but the efficiency of separation and recovery is reduced because it adheres to the walls of the stirring tank, etc. during separation and recovery. Furthermore, if the thickness of the base material layer is thicker than the above range, not only are the processability, transparency, and handling properties inferior, but the load on the separation and recovery equipment increases, making stable separation and recovery difficult.

[0019] <Polyamide resin> The polyamide resin constituting the base layer is preferably an aliphatic polyamide resin (a). The base layer preferably contains aliphatic polyamide resin (a) as its main component. In this specification, "main component" means that the proportion of aliphatic polyamide resin (a) to the base layer is 50% by mass or more, more preferably 60% by mass or more, even more preferably 70% by mass or more, even more preferably 80% by mass or more, and particularly preferably 90% by mass or more. The content of aliphatic polyamide resin (a) in the base layer may also be 100% by mass.

[0020] Aliphatic polyamide resin (a) is a polyamide resin produced by ring-opening polymerization of various known lactams, and is a polyamide resin produced by condensation polymerization of known aliphatic diamines and aliphatic dicarboxylic acids. Examples of aliphatic polyamide resin (a) include polyamide 4, polyamide 6, polyamide 7, polyamide 11, polyamide 12, polyamide 46, polyamide 410, polyamide 510, polyamide 66, polyamide 610, polyamide 6 / 66, polyamide 6 / 610, polyamide 612, polyamide 6 / 612, polyamide 1010, etc. Among these, polyamide 6, polyamide 66, and polyamide 6 / 66 are preferred from the viewpoint of film-forming properties and versatility, and polyamide 6 is more preferred.

[0021] The base layer may contain other resin components in addition to the aliphatic polyamide resin (a). Examples of other resin components include thermoplastic elastomers. Examples of thermoplastic elastomers include styrene elastomers, vinyl chloride elastomers, olefin elastomers, polyester elastomers, polyamide elastomers, urethane elastomers, and acid-modified versions thereof. Among these, polyamide elastomers are preferred due to their high compatibility with the aliphatic polyamide resin (a), improved pinhole resistance of the film, and transparency. In this case, the content of the thermoplastic elastomer is preferably 50% by mass or less, more preferably 40% by mass or less, and even more preferably 30% by mass or less, based on the total mass of the base layer.

[0022] If the base layer mainly contains a polyamide resin, the base layer may also have a gas barrier layer in addition to the polyamide resin layer. The gas barrier layer is a layer containing a gas barrier resin (b), and such a gas barrier layer may be provided as a single layer or as multiple layers. If multiple gas barrier layers are provided, the resin composition of each layer may be different.

[0023] Examples of gas barrier resins (b) include polymetaxylylene adipamide (polyamide MXD6), metaxylylene / paraxylylene adipamide copolymers, and copolymers obtained by copolymerizing these with aromatic diamines, aromatic dicarboxylic acids, lactams, ω-aminocarboxylic acids, aromatic aminocarboxylic acids, etc. Among these, polymetaxylylene adipamide (polyamide MXD6) is preferred from the viewpoint of gas barrier properties and moldability.

[0024] Furthermore, ethylene-vinyl acetate copolymer saponified products can also be used as the gas barrier resin (b). Ethylene-vinyl acetate copolymer saponified products are copolymers obtained by saponifying a copolymer of ethylene and vinyl acetate with an alkaline catalyst or the like, and may further contain ethylene structural units, vinyl alcohol structural units (including unsaponified vinyl ester structural units), and structural units derived from the following comonomers. Examples of comonomers include α-olefins such as propylene, isobutene, α-octene, α-dodecene, and α-octadecene; hydroxyl group-containing α-olefins such as 3-buten-1-ol, 4-penten-1-ol, and 3-buten-1,2-diol, and hydroxyl group-containing α-olefin derivatives such as their esterified and acylated products; unsaturated carboxylic acids or their salts, partially alkyl esters, fully alkyl esters, nitriles, amides, or anhydrides; unsaturated sulfonic acids or their salts; vinylsilane compounds; vinyl chloride; styrene, etc.

[0025] Furthermore, as the gas barrier resin (b), ethylene-vinyl alcohol copolymers that have been post-modified by urethaneization, acetalization, cyanoethylation, oxyalkyleneization, etc., can also be used. These ethylene-vinyl alcohol copolymers may be used individually or as a mixture of two or more types.

[0026] The ethylene content in the ethylene-vinyl acetate copolymer saponified product and the ethylene-vinyl alcohol copolymer is not particularly limited, but from the viewpoint of film formation stability, it is preferably 5 mol% or more, more preferably 10 mol% or more, and particularly preferably 20 mol% or more. From the viewpoint of gas barrier properties, the upper limit of the ethylene content is preferably 48 mol% or less, more preferably 38 mol% or less, and even more preferably 35 mol% or less. Furthermore, the degree of saponification of the ethylene-vinyl acetate copolymer saponified product is preferably 96% or more, and more preferably 98% or more. When the ethylene content in the ethylene-vinyl acetate copolymer saponified product and the ethylene-vinyl alcohol copolymer in the gas barrier layer, and the degree of saponification in the ethylene-vinyl acetate copolymer saponified product are within the above ranges, an excellent balance between film formation and gas barrier properties is obtained, making it suitable for molding and processing.

[0027] When the substrate layer has a gas barrier layer, the gas barrier layer only needs to contain a gas barrier resin (b) as its main component, but may also contain other resin components. Examples of other resin components include thermoplastic elastomers. Examples of thermoplastic elastomers include styrene elastomers, vinyl chloride elastomers, olefin elastomers, polyester elastomers, polyamide elastomers, urethane elastomers, and acid-modified versions thereof. In this case, the content of other resin components is preferably 50% by mass or less, more preferably 40% by mass or less, and even more preferably 30% by mass or less, based on the total mass of the gas barrier layer.

[0028] <Polyester resin> The base layer may contain a polyester resin. In this case, examples of polyester resins include aliphatic polyester, aliphatic aromatic polyester, aromatic polyester, and the like.

[0029] Examples of aliphatic polyesters include polymers mainly composed of lactic acid, and copolymers of dicarboxylic acids (such as succinic acid and adipic acid) and diols (such as ethylene glycol and 1,4-butanediol). Examples of polymers mainly composed of lactic acid include homopolymers consisting only of lactic acid, copolymers obtained by copolymerizing lactic acid with monomers other than lactic acid, and mixtures thereof. Examples of monomers other than lactic acid include oxyacids (such as malic acid and glycolic acid), 3-hydroxybutyrate, 3-hydroxyvalylate, and caprolactone.

[0030] Examples of aliphatic aromatic polyesters include copolymers of dicarboxylic acids (such as succinic acid, adipic acid, and terephthalic acid) and diols (such as ethylene glycol and 1,4-butanediol). Specifically, examples include polyethylene terephthalate succinate, polybutylene adipate terephthalate, and polytetramethylene adipate terephthalate.

[0031] Examples of aromatic polyesters include polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate.

[0032] <Polyolefin resins> The base layer may contain a polyolefin resin. In this case, examples of polyolefin resins include polyethylene and polypropylene. Among these, polypropylene is preferred. The polyolefin resin may be acid-modified polypropylene obtained by graft-modifying polypropylene with an unsaturated carboxylic acid, an acid anhydride of an unsaturated carboxylic acid, an ester of an unsaturated carboxylic acid, etc. In addition, as the polyolefin resin, polypropylene resins such as homopolypropylene resin (PP), propylene-ethylene random copolymer, propylene-ethylene block copolymer, and propylene-α-olefin copolymer can be used.

[0033] <Optional ingredients> Various known additives can be mixed into the base layer. Examples include fillers, lubricants, antiblocking agents, antioxidants, heat stabilizers, light stabilizers, UV absorbers, colorants, antifogging agents, mold release agents, flame retardants, slip agents, tackifiers, and antistatic agents. In particular, antioxidants and heat stabilizers may be included in the base layer to prevent degradation.

[0034] The substrate layer may be surface-treated. Examples of surface treatments include corona treatment, low-pressure plasma treatment, atmospheric pressure plasma treatment, flame treatment, ion bombardment treatment, chemical treatment, and solvent treatment. When surface treatment is applied, it is preferable that the surface treatment is applied to the side on which the printed layer (A), etc., described later, is provided.

[0035] <Method for manufacturing the base layer> The resin film constituting the base layer may be a stretched film or an unstretched film. However, from the viewpoint of impact resistance, heat resistance, water resistance, dimensional stability, etc., the resin film is preferably a stretched film. The stretching method is not particularly limited, and any method is acceptable as long as a dimensionally stable film can be supplied, such as stretching by inflation, uniaxial stretching, or biaxial stretching.

[0036] A known method can be used for manufacturing the resin film. Preferably, the method includes a step of supplying the resin constituting the resin film to an extruder, melting it, and then extruding it. If the resin film is a multilayer film, it is preferable to include a step of supplying the resin constituting each layer to its respective extruder, melting it, and then co-extruding them. During extrusion, the molten resin is combined in a feed block, or a flat die or annular die of a multi-manifold, then co-extruded as a multilayer film, and finally rapidly cooled to obtain a flat or annular unstretched film. For example, the temperature of the extruder containing the polyamide resin is preferably 200 to 300°C.

[0037] To obtain a biaxially oriented film, an unstretched film is biaxially stretched in the direction of film flow (longitudinal direction, MD) and the width direction perpendicular to it (transverse direction, TD) using known methods such as tenter-type sequential biaxial stretching, tenter-type simultaneous biaxial stretching, or tubular-type simultaneous biaxial stretching. For example, when performing tenter-type sequential biaxial stretching on a polyamide resin film, the unstretched film is heated to a temperature range of 40 to 100°C, stretched longitudinally using a roll-type longitudinal stretcher, and then stretched transversely using a tenter-type transverse stretcher at a temperature range of 150 to 230°C. In the case of tenter-type simultaneous biaxial stretching or tubular-type simultaneous biaxial stretching, for example, the film can be produced by stretching in both the longitudinal and transverse directions simultaneously at a temperature range of 40 to 230°C.

[0038] The stretching ratio is preferably 1.5 to 5.0 times in the film's flow direction (longitudinal direction, MD) and width direction (transverse direction, TD), and more preferably 2.0 to 4.5 times in each direction. Having the stretching ratio in the biaxial stretching direction within this range promotes stretch orientation, resulting in good mechanical properties such as film strength.

[0039] Furthermore, to improve the dimensional stability of the film, the biaxially oriented film can be heat-set. The heat-set temperature is preferably 200 to 225°C, and more preferably 205 to 220°C. This makes it possible to obtain a biaxially oriented film with good dimensional stability at room temperature.

[0040] To alleviate the stress of crystallization shrinkage due to heat fixation, a relaxation treatment can be performed during heat fixation in the width direction by 0-15%, preferably 3-10%. After the relaxation treatment, re-stretching can be performed at a temperature of 140-200°C in the width direction by 2-9%, preferably 3-7%, and more preferably 4-7%. If the re-stretching temperature is within the above range, an appropriate stress during stretching can be obtained, resulting in uniform stretching and a more even lateral shrinkage rate in the width direction.

[0041] <Print layer (A)> The laminate used in this embodiment preferably has a printed layer (A). The printed layer (A) is provided in a position visible from the outside of the laminate for the purpose of displaying information about the contents, identifying the contents, improving concealment, or improving the design of the packaging bag. The printing method and printing ink are not particularly limited and are appropriately selected from known printing methods and printing inks, taking into consideration suitability for printing on the film, design such as color tone, adhesion, and safety as a container. The printed layer (A) preferably contains a resin such as polyvinyl resin, polyamide resin, polyester resin, acrylic resin, polyurethane resin, polyvinyl acetal resin, polyester urethane resin, cellulose ester resin, or alkyd resin as a binder. In particular, the printed layer (A) preferably contains at least one resin selected from the group consisting of acrylic resins, polyurethane resins, polyester resins, polyamide resins, vinyl chloride vinyl acetate copolymer resins, and nitrocellulose resins; more preferably contains at least one resin selected from the group consisting of acrylic resins, polyurethane resins, polyester resins, and polyamide resins; and even more preferably contains at least one resin selected from the group consisting of acrylic resins, polyurethane resins, and polyester resins.

[0042] Furthermore, the printed layer preferably contains a pigment or dye of an appropriate color as a coloring agent in addition to the resin described above. For the printing ink, it is preferable to use a colored ink containing the binder resin described above and a pigment or dye as a coloring agent.

[0043] Printing methods that can be used include, for example, gravure printing, offset printing, gravure-offset printing, flexographic printing, and inkjet printing. Among these, gravure printing is preferred from the viewpoint of productivity and high resolution of the image.

[0044] The thickness of the printed layer is not particularly limited as long as it can achieve design and opacity, but from the viewpoint of improving the applicability of the printing ink and suppressing deformation of the substrate layer due to resin shrinkage during drying, it is preferably 10 μm or less, more preferably 5 μm or less.

[0045] <Adhesive resin layer (B)> The laminate used in this embodiment preferably has an adhesive resin layer (B). The adhesive resin layer (B) is provided between the substrate layer and the sealant layer (C) described later. If the printed layer (A) described above is provided, it is preferable that the adhesive resin layer (B) is provided between the printed layer (A) and the sealant layer (C) described later.

[0046] A known adhesive resin can be used for the adhesive resin layer (B). Examples of adhesive resins include at least one selected from the group consisting of urethane resins, ester resins, epoxy resins, and acrylic resins, and it is preferable that the adhesive resin layer (B) contains at least one selected from the group consisting of urethane resins, ester resins, epoxy resins, and acrylic resins.

[0047] The thickness of the adhesive resin layer (B) is not particularly limited, but is preferably 1 to 10 μm, and more preferably 2 to 5 μm.

[0048] The adhesive resin layer (B) is preferably a coated layer formed by applying an adhesive. The adhesive application method and materials may be one-component or two-component. In addition, the adhesive may contain a crosslinking agent in addition to the adhesive resin.

[0049] As for the adhesive resin, it is preferable to use an ester-based adhesive from the viewpoint of interlayer adhesion. Furthermore, the adhesive is preferably a two-component system consisting of a polyol and a crosslinking agent. Examples of polyols include polyester-based, polyether-based, and acrylic-based polyols, and examples of crosslinking agents include aromatic isocyanates, aliphatic isocyanates, carbodiimides, and epoxy crosslinking agents. In this embodiment, it is preferable that the adhesive resin layer (B) is dissolved in the step of (2) peeling off each layer of the laminate using an alkaline release agent (P) containing a polar solvent, thereby peeling off each layer. For this reason, from the viewpoint of ease of dissolving the adhesive resin layer (B), it is preferable to use an adhesive made of a polyester-polyurethane system formed by crosslinking a polyester-based polyol and an aliphatic isocyanate.

[0050] The adhesive may contain an organic solvent or water to improve its application properties. Alternatively, the adhesive may be solvent-free.

[0051] The adhesive can be applied using methods such as gravure printing, roll coating, or T-die printing. Of these, gravure printing is preferable from the standpoint of productivity.

[0052] <Sealant layer (C)> The laminate used in this embodiment preferably has a sealant layer (C). There are no particular restrictions on the resin constituting the sealant layer (C), but known polyolefin resins such as polyethylene resins and polypropylene resins can be used.

[0053] In particular, the sealant layer (C) preferably contains a polyethylene resin. The polyethylene resin may be an ethylene homopolymer, a copolymer of ethylene and an α-olefin having 3 to 20 carbon atoms, and may be any of ultra-low density polyethylene, low density polyethylene, linear low density polyethylene, medium density polyethylene, or high density polyethylene. Among these, low density polyethylene and linear low density polyethylene are preferred as polyethylene resins from the viewpoint of heat sealability and versatility. These may be used individually or in mixtures of two or more types.

[0054] Polypropylene resins may be propylene homopolymers or copolymers of propylene and α-olefins having 2 to 20 carbon atoms. Among these, propylene-ethylene random copolymers are preferred from the viewpoint of heat sealability and versatility. These may be used individually or as a mixture of two or more.

[0055] The sealant layer (C) can be formed by known lamination methods. For example, a dry lamination method in which a film-like sealant layer is bonded to an adhesive resin layer (B), or an extrusion lamination method in which the above-mentioned polyethylene-based resin or polypropylene-based resin is heated and melted, extruded onto the substrate layer or adhesive resin layer (B), and bonded together can be employed. Among these, the dry lamination method is preferred.

[0056] The thickness of the sealant layer can be appropriately changed depending on the form and weight of the contents. If the contents are solid or lightweight, the thickness of the sealant layer may be thin, while if the contents are liquid or heavy, a thicker sealant layer is preferable. The thickness of the sealant layer is preferably, for example, 20 to 300 μm, and more preferably 25 to 200 μm.

[0057] <Other layers> The laminate used in this embodiment may have other layers in addition to the layers described above. Examples of other layers include a barrier layer. The barrier layer only needs to have the function of suppressing the intrusion of moisture and oxygen from the outside in order to protect the contents, and may be a metal foil, a metal vapor-deposited film, a metal oxide film, etc. For metal foil, it is formed by laminating it with an adhesive using a known method. Metal vapor-deposited films and metal oxide films are also formed on the substrate layer using known methods such as sputtering or vacuum deposition.

[0058] Other layers include antistatic layers, release layers, high refractive index layers, scattering layers, polarizing layers, heat-shielding layers, UV degradation prevention layers, hydrophilic layers, antifouling layers, anti-fogging layers, moisture-proof layers, photocatalytic layers, corrosion-resistant layers, fingerprint-resistant layers, hard layers, conductive layers, anti-glare layers, and diffusion layers. The separation and recovery method of the laminate according to this embodiment can separate and recover at least the base layer from the laminate, even if these other layers are provided.

[0059] <(1) Process of crushing the laminate> The method for separating and recovering the laminate according to this embodiment includes (1) a step of crushing the laminate (hereinafter also referred to as step (1)). In step (1), a dry or wet crusher is used to cut the laminate, which is in the form of a film, pouch, or other shape, to produce crushed material (fluff). As for the crusher, there are wet crushers that crush while adding moisture, and dry crushers that crush in a dry state. When the laminate is thin, it is preferable to crush it using a wet method, which has a cooling effect, so that the laminate is not cut while stretched due to the shear heat generated during crushing.

[0060] The laminate can be crushed using a known crusher, such as a film crusher. In the crusher, it is preferable that excessive heat is not applied to the molded body or fluff due to friction between the inside of the device and the molded body or fluff, so that the laminate and the crushed material (fluff) do not deteriorate due to heat.

[0061] There are no particular restrictions on the shape of the pulverized material (fluff), and it is generally irregular or polygonal. However, to prevent the fluff from becoming entangled, it is preferable that the length and width are roughly equal, and a roughly square shape is more preferable.

[0062] The crusher has a screen that regulates the size of the crushed pieces, and only the pieces that pass through the opening of the screen are collected as fluff. The shape of the opening of the screen is generally a round hole. The size of the round hole is important in determining the size of the fluff. From the viewpoint of the release agent (P) penetrating into the interior of the laminate from the cut edge of the laminate in the subsequent peeling process, the diameter of the opening of the screen is preferably 20 mm or less, and more preferably 15 mm or less. Also, from the viewpoint of minimizing the loss of fluff in the processes after centrifugation following peeling, the diameter of the opening of the screen is preferably 1 mm or more, and more preferably 3 mm or more. In other words, the long side of the obtained crushed material (fluff) is preferably 20 mm or less, more preferably 15 mm or less. Also, the long side of the crushed material (fluff) is preferably 1 mm or more, and more preferably 3 mm or more.

[0063] <(2) Step of peeling off each layer of the laminate using an alkaline release agent (P) containing a polar solvent> The method for separating and recovering a laminate according to this embodiment includes (2) a step of peeling off each layer of the laminate using an alkaline release agent (P) containing a polar solvent (hereinafter also referred to as step (2)). In step (2), it is preferable to use an apparatus equipped with a stirring tank for introducing and processing the release agent (P) and the laminate, and a stirrer for mixing, fluidizing, and stirring the release agent (P) and the laminate. In step (2), the laminate is immersed in the release agent (P) and further stirred to dissolve the printed layer (A), adhesive resin layer (B), various resins and additives, and separate at least the base layer from the laminate by peeling off each layer. If the laminate has a sealant layer (C), it is preferable that in step (2), the base layer and the sealant layer (C) are peeled off and separated, respectively.

[0064] In step (2), it is preferable that the laminate is firmly dispersed in the depth direction of the tank into which the release agent (P) is introduced. For this purpose, in step (2), the total volume of the laminate and the release agent (P) is 1 m 3 per unit stirring power value (value obtained by subtracting the power required for idling operation from the power applied for stirring) is preferably 10 W / m 3 or more, more preferably 11 W / m 3 or more, even more preferably 12 W / m 3 or more, still more preferably 15 W / m 3 or more, yet more preferably 20 W / m 3 or more, particularly preferably. On the other hand, when the stirring power value becomes high, the deterioration of the base material layer and the sealant layer may progress due to shear during stirring, not only causing a deterioration in quality such as the strength of the product after being used as a recycled material, but also the possibility that the base material layer and the sealant layer are crushed into microplastics during stirring. Therefore, the stirring power value is preferably 1200 W / m 3 or less, and more preferably 800 W / m 3 or less.

[0065] The stirring power value is an index of the force for peeling each layer of the laminate using the release agent (P), and is the power value required for stirring per 1 m 3 of the total volume of the laminate and the release agent (P) in step (2). Specifically, it is the value obtained by subtracting the power (W) required for idling operation from the power (W) applied for stirring 1 m 3 of the total volume of the laminate and the release agent (P). When calculating the stirring power value, measure the power when the laminate is introduced into the release agent (P) and the stirring blade is rotated, subtract the power during idling operation measured in advance, and divide the difference by the volume of the mixture of the introduced release agent and the laminate. Since the stirring power value varies depending on the flow state of the mixture of the release agent (P) and the laminate, the distribution state of the laminate, and other factors, and it is difficult to maintain a constant value, it is represented by the average value from the start to the end of the peeling process.

[0066] It is preferable that the laminate in the release agent (P) is well dispersed in the depth direction of the release agent (depth direction of the stirring tank). For example, it is preferable that the laminate in the release agent (P) moves in a circulating flow that penetrates from the center of the tank in the depth direction from the surface and then rises again from the wall side. If such a circulating flow is generated, it becomes easier to uniformly distribute the dissolved adhesive, printing ink, and various resins from the laminate into the release agent (P), and by uniformly dispersing the laminate in the release agent, the peeling performance is made uniform and the difficulty in peeling due to interference between laminates can be eliminated. In order to generate such a circulating flow, in this embodiment it is preferable to set the stirring power value (the value obtained by subtracting the power for dry running from the power for stirring) within a predetermined range.

[0067] In order to keep the stirring power value (the power required for stirring minus the power required for dry running) within a predetermined range, it is preferable to adjust the concentration of the laminate in the release agent (P). Specifically, in step (2), the mass ratio of the laminate to the total mass of the release agent (P) and the laminate (100% by mass) is preferably 3% by mass or more, and more preferably 5% by mass or more. Furthermore, the mass ratio of the laminate to the total mass of the release agent (P) and the laminate (100% by mass) is preferably 20% by mass or less, and more preferably 15% by mass or less.

[0068] Furthermore, in order to keep the stirring power value (the power required for stirring minus the power required for dry running) within a predetermined range, it is preferable to appropriately control the stirring conditions. For example, the rotation speed of the stirring blades can be appropriately controlled, the shape and number of stirring blades can be redesigned, the shape and number of baffles installed on the walls of the stirring tank can be redesigned, and the shape of the stirring tank itself can be redesigned. The stirring power value can also be adjusted by controlling the concentration of the laminate in the release agent (P).

[0069] In step (2), it is preferable to appropriately control the temperature of the release agent in order to further improve the peelability of each layer of the laminate. For example, the temperature of the release agent (P) in step (2) is preferably 70°C or higher, and more preferably 75°C or higher. Furthermore, the temperature of the release agent (P) is preferably 100°C or lower, and more preferably 95°C or lower. By setting the temperature of the release agent (P) above the lower limit, the peeling performance can be more effectively improved. Also, since the release agent contains water, by setting the temperature of the release agent (P) below the upper limit, it is possible to suppress changes in the component composition due to the boiling of water. It is preferable that the stirring tank has a temperature control mechanism using steam, hot water, electric heating, etc., and it is preferable that it has a mechanism that can adjust the temperature of the release agent to the optimal temperature for dissolution treatment and peeling treatment.

[0070] The immersion and stirring time in step (2) is preferably 1 to 5 hours, and more preferably 2 to 4 hours. The above time can be adjusted as appropriate, taking into account the stirring power value and stirring conditions.

[0071] <Removal agent (P)> The stripping agent (P) used in step (2) is an alkaline stripping agent containing a polar solvent. In particular, the stripping agent (P) preferably contains a polar solvent, a quaternary ammonium salt, and water.

[0072] Examples of polar solvents include diethylene glycol monobutyl ether, isopropanol, N-methyl-2-pyrrolidone, dimethylformamide, dimethyl sulfoxide, and benzyl alcohol. These may be used individually or in combination of two or more.

[0073] The content of the polar solvent is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 65% ​​by mass or more, based on the total mass of the release agent (P). On the other hand, the content of the polar solvent is preferably 90% by mass or less, more preferably 80% by mass or less, and even more preferably 75% by mass or less, based on the total mass of the release agent (P).

[0074] Examples of quaternary ammonium salts include dimethylbis(2-hydroxyethyl)ammonium hydroxide, monomethyltris(2-hydroxyethyl)ammonium hydroxide, trimethyl-2-hydroxyethylammonium hydroxide, and tetraalkylammonium hydroxides (such as tetramethylammonium hydroxide) whose pH in a 1% aqueous solution is 11.5 or higher.

[0075] The content of the above-mentioned quaternary ammonium salt is preferably 1% by mass or more, more preferably 3% by mass or more, and even more preferably 5% by mass or more, based on the total mass of the release agent (P). On the other hand, the upper limit of the content is preferably 20% by mass or less, more preferably 18% by mass or less, and even more preferably 15% by mass or less, based on the total mass of the release agent (P).

[0076] The release agent (P) can dissolve layers and / or films of polyester resins such as polyethylene terephthalate, layers and / or films of ethylene vinyl alcohol resins, printed layers, etc. On the other hand, layers and / or films of polyamide resins and layers and / or films of polyolefin resins do not dissolve in the release agent (P). Therefore, in step (2), the printed layer (A) and / or adhesive resin layer (B) of the laminate dissolve, while the base layer and / or sealant layer (C) of the laminate do not dissolve in the release agent (P), and these layers are peeled off. By appropriately changing the composition of the release agent (P), it is possible to separate and recover only one of the base layer or the sealant layer (C), or to separate and recover both the base layer and the sealant layer (C). In other words, the separation and recovery method in this embodiment is preferably a method of separating the laminate and recovering the polyamide resin and / or polyolefin resin.

[0077] It is preferable that the release agent (P) is substantially free of acidic components. Specifically, the acidic component content relative to the total mass of the release agent (P) is preferably 1% by mass or less, and more preferably 0.1% by mass or less. Thus, in this embodiment, since no acid is used for dissolution and peeling with the release agent (P), and no high-temperature heating process exceeding 100°C is performed, hydrolysis and deterioration of the substrate layer and sealant layer can be suppressed. As a result, it can be reused at the same level as new resin, which is called virgin pellets.

[0078] <(3) A step of washing the peeled layer using a rinse agent (Q) containing a polar solvent and / or a surfactant.> The method for separating and recovering the laminate according to this embodiment includes (3) a step of washing the peeled layer pieces using a rinse agent (Q) containing a polar solvent and / or a surfactant (hereinafter also referred to as step (3)). In step (3), an apparatus equipped with a stirring tank for introducing and processing the release agent and the base layer of the laminate, and a stirrer for mixing, fluidizing, and stirring the rinse agent (Q) and the base layer of the laminate, is used to immerse and stir the base layer and sealant layer that have been peeled off from the laminate in the rinse agent (Q) to wash away the release agent, the printed layer (A), the adhesive resin layer (B), dissolved resins and additives, and other contaminants adhering to the base layer and sealant layer.

[0079] In step (2), the substrate layer and sealant layer (C) can be separated by treating with a release agent (P), while the print layer (A), adhesive resin layer (B), etc., are dissolved in the release agent (P) used in step (2). In particular, the print layer (A) contains pigments and dyes, so these pigments and dyes tend to adhere to the surface of the substrate layer and sealant layer (C). Therefore, in step (3), the pigments, dyes, and adhesive resins can be removed by washing with a rinse agent (Q). This suppresses the adsorption of pigments, dyes, and adhesive resins onto the surface of the substrate layer and sealant layer (C) and causes discoloration. To improve the cleaning effect, it is preferable to add rinse agent (Q) in such a way that the concentration of pigments, dyes, adhesive resins, etc. contained in rinse agent (Q) is reduced.

[0080] In the cleaning tank, it is preferable that the detached substrate layer and sealant layer are well dispersed in the depth direction of the rinse agent (Q) (the depth direction of the cleaning tank). For example, it is preferable that the substrate layer and sealant layer move in the rinse agent (Q) in a circulating flow that penetrates from the surface in the depth direction from the center of the tank and then rises again from the wall side. If such a circulating flow is generated, it becomes easier to uniformly distribute the dissolved adhesive, printing ink, and various resins from the laminate into the rinse agent (Q), thereby equalizing the cleaning performance and eliminating the difficulty of cleaning due to interference between substrate layers. As a result, cleaning can be performed efficiently. In order to generate such a circulating flow, the stirring speed, the shape and number of stirring blades may be adjusted, or the shape of the tank itself may be appropriately designed.

[0081] In step (3), the total volume of the peeled layer fragments (substrate layer and sealant layer) and the rinse agent (Q) is 1 m³. 3 The stirring power value per unit (the power used for stirring minus the power used for dry running) is 10 W / m². 3 Preferably, it is 11 W / m 3 It is more preferable that the value be 12 W / m 3 It is even more preferable that the value be 15 W / m 3 It is even more preferable that the value be 20 W / m 3 The above is particularly preferable. On the other hand, if the stirring power value is too high, the shear during stirring may accelerate the deterioration of the base material layer and sealant layer, which not only leads to a decrease in the quality of the product after it has been used as recycled material, but it is also possible that the base material layer and sealant layer may be crushed into microplastics during stirring. For this reason, the stirring power value should be 1200 W / m 3 Preferably, it is 800W / m 3 The following is even more preferable. Note that the stirring power value fluctuates depending on the flow state of the mixture of the rinse agent (Q) and the peeled layer fragments, the distribution of the laminate, and other factors, making it difficult to maintain a constant value. Therefore, it is expressed as the average value from the start to the end of the peeling process.

[0082] In order to keep the stirring power value (the power required for stirring minus the power required for dry running) within a predetermined range, it is preferable to adjust the concentration of the detached layer fragments in the rinse agent (Q). Specifically, in step (3), the mass ratio of the detached layer fragments to the total mass of the rinse agent (Q) and the detached layer fragments (100% by mass) is preferably 3% by mass or more, and more preferably 5% by mass or more. Furthermore, the mass ratio of the detached layer fragments to the total mass of the rinse agent (Q) and the detached layer fragments (100% by mass) is preferably 20% by mass or less, and more preferably 15% by mass or less.

[0083] In step (3), the temperature of the rinse agent (Q) is preferably 10°C or higher, and more preferably 15°C or higher. Furthermore, the temperature of the rinse agent (Q) is preferably less than 70°C, and more preferably 60°C or lower. By setting the temperature of the rinse agent (Q) within the above range, the cleaning performance can be more effectively enhanced. The cleaning tank is preferably equipped with a temperature control mechanism using steam, hot water, electric heating, etc., and is preferably equipped with a mechanism that can adjust the temperature of the rinse agent to the optimal temperature for the cleaning process. In this embodiment, the processing temperatures of step (2) and step (3) are different, and the process when the processing temperature is 70°C or higher can be distinguished as the stripping process (step (2)), and the process when the processing temperature is less than 70°C can be distinguished as the cleaning process (step (3)).

[0084] The immersion and stirring time in step (3) is preferably 3 minutes or more, more preferably 5 minutes or more, and even more preferably 8 minutes or more. The immersion and stirring time is preferably 60 minutes or less, more preferably 30 minutes or less, and even more preferably 20 minutes or less. The above times can be adjusted as appropriate, taking into account the stirring power value and stirring conditions.

[0085] Step (3) may be performed only once or multiple times. If step (3) is performed multiple times, the rinse agent (Q) used in each step may be the same or of different types. For example, if step (3) is performed multiple times, it is more preferable that the first step (3) contains both the same polar solvent and the same quaternary ammonium salt as the release agent (P). Also, if step (3) is performed multiple times, the stirring power values ​​in each step may be different. For example, the stirring power value of the second and subsequent steps (3) may be smaller than the stirring power value of the first step (3).

[0086] <Rinse (Q)> The rinse agent (Q) used in step (3) is not particularly limited, but for example, a solution containing a polar solvent and / or a surfactant can be used. The rinse agent (Q) is preferably alkaline from the viewpoint of more effectively enhancing cleaning ability, and in this case, it is more preferably an alkaline solution containing a polar solvent. For example, if step (3) is provided multiple times, an alkaline solution containing a polar solvent may be used in the first step (3), and a solution containing a surfactant may be used in the second and subsequent steps (3). The solution containing the surfactant may be an alkaline solution, a neutral solution, or an acidic solution.

[0087] If the rinse agent (Q) is an alkaline solution containing a polar solvent, it is preferable that the rinse agent (Q) contains a polar solvent, a quaternary ammonium salt, and water. Examples of the polar solvent and quaternary ammonium salt include those listed for the release agent (P), and it is preferable that it contains either the same polar solvent or the same quaternary ammonium salt as the release agent (P), and more preferably both the same polar solvent and the same quaternary ammonium salt as the release agent (P). In this case, it is preferable that the compositions of the release agent (P) and the rinse agent (Q) are similar; for example, the ratio (composition) of the polar solvent, quaternary ammonium salt, and water is similar to each other, and the compositions of the release agent (P) and the rinse agent (Q) may be identical. By using a rinse agent (Q) with a composition similar to that of the release agent (P), it becomes easier to effectively remove the adhesive resin layer, printing layer, various resins, etc., dissolved in the release agent while preventing precipitation.

[0088] If the rinse agent (Q) is a solution containing a surfactant, an aqueous solution of a nonionic surfactant can be used. The nonionic surfactant is not particularly limited, but examples include polyoxyalkylene glycol fatty acid esters, polyalkylene glycol fatty acid esters, and polyoxyalkylene alkyl ethers. One nonionic surfactant may be used alone, or two or more may be used in combination. For example, from the viewpoint of cleaning performance, it is desirable that the nonionic surfactant be at least one selected from the group consisting of polyethylene glycol monooleate, polyethylene glycol monopalmitate, and polyethylene glycol monostearate. The concentration of the surfactant in the rinse agent (Q) is not particularly limited, but is preferably 0.01 to 5% by mass. Furthermore, if the rinse agent (Q) is a solution containing a surfactant, the solution containing the surfactant may be an alkaline solution, a neutral solution, or an acidic solution.

[0089] The rinse agent (Q) may contain both a polar solvent and a surfactant. For example, the rinse agent (Q) may be a neutral solution containing a polar solvent and a surfactant, or it may be an alkaline solution containing a polar solvent and a surfactant.

[0090] (4) A step in which the release agent and / or rinsing agent remaining on the layer fragments peeled off in the previous step are centrifuged using a separator. The method for separating and recovering the laminate according to this embodiment includes (4) a step of centrifuging the release agent and / or rinse agent remaining on the layer pieces peeled off in the previous step using a separator (hereinafter also referred to as step (4)). In step (4), for example, a centrifuge is used to centrifuge and remove the release agent and rinse agent remaining on the layer pieces peeled off in the previous step, as well as adhesives dissolved in the release agent and rinse agent, printing inks, various resins and additives, etc., together with the release agent and rinse agent.

[0091] There are two main types of centrifugal separation methods: continuous and batch. The continuous method involves continuously feeding the processing liquid into the centrifuge, and processing the liquid removal and discharge in parallel. The batch method involves placing a fixed amount of processing liquid into a basket and rotating it, repeating the process of "start-up-liquid removal-stop-discharge" as one cycle. When this cycle is stopped, the removed substrate layer and sealant layer adhere to the inner wall of the basket in a thick state; this thick adhered state is generally called the cake layer. There are no particular restrictions on the type of centrifuge used in process (4), but in the batch method, attention must be paid to the variation in the thickness of the cake layer in the basket produced in each batch.

[0092] It is preferable to have less release agent and rinse agent remaining in the substrate layer and sealant layer after centrifugation, as this reduces the leakage of the release agent and rinse agent itself, as well as the adhesives, printing inks, resins, and additives dissolved in the release agent and rinse agent, into subsequent processes.

[0093] The liquid content of the detached fluff obtained as a cake layer after centrifugation is preferably 35% by mass or less, and more preferably 30% by mass or less. The lower limit of the liquid content is not particularly limited and may be 0% by mass. The liquid content is calculated by the following method. First, 10 g of the detached fluff obtained as a cake layer after centrifugation is weighed out, its weight is recorded, and it is placed in a 500 mL beaker and washed several times with 2-propanol. The washed fluff is placed in a dryer set to 80°C and pre-dried for 3 hours, and then vacuum-dried in a vacuum dryer set to 90°C for 18 hours. The weight of the dried fluff is measured, and the liquid content is calculated from the fluff weight after centrifugation and the fluff weight after drying.

[0094] (5) Step of separating the layer fragments peeled off in the previous step. The method for separating and recovering the laminate according to this embodiment includes (5) a step of separating the layer fragments peeled off in the previous step (hereinafter also referred to as step (5)). In step (5), a sedimentation separation device such as a centrifuge is used to put the layer fragments peeled off in the previous step into a specific gravity separation liquid and separate the layer fragments peeled off in the previous step by resin type by sedimentation separation such as centrifugal sedimentation or gravity sedimentation. For example, if the base layer is composed of a polyamide resin and the sealant layer (C) is composed of a polyolefin resin, the polyamide resin and the polyolefin resin can be separated by specific gravity separation. Since the specific gravity of polyamide resin is 1.00 to 1.25 and the specific gravity of polyolefin resin is 0.870 to 0.970, it is desirable to use water as the specific gravity separation liquid, as it has a specific gravity of 1 and is easy to handle. On the other hand, the specific gravity of the specific gravity separation liquid may be adjusted within the range of 0.9 to 1.1. The water can be any clean water, such as tap water, industrial water, or well water. A surfactant may be used as an additive to the gravity separation solution to improve dispersibility by reducing surface tension.

[0095] After separation using the difference in specific gravity, the liquid phase components are dried using known methods. Drying methods include hot air drying, direct drying, and compression drying. If the laminate contains multiple types of polyamide resins, these multiple resins are separated together as polyamide resin fluff. Similarly, if the laminate contains multiple types of polyolefin resins, these multiple resins are separated together as polyolefin resin fluff.

[0096] <Other processes> In addition to steps (1) to (5), the method for separating and recovering the laminate in this embodiment may include a step of washing the layer pieces with a water-containing solution, more preferably water, in order to remove the release agent (P) and rinse agent (Q) used in steps (2) and (3) from the layer pieces. After washing the layer pieces with a water-containing solution, a step of (4) centrifugation may be included as needed. Note that the same washing conditions as in step (3) washing the peeled layer pieces may be used in the step of washing the layer pieces with a water-containing solution.

[0097] The separation and recovery method of the laminate according to this embodiment may include a step of processing the resin separated and recovered through the above-described step (5) into pellets or sheets. The resin recovered by the separation and recovery method of this embodiment can be reused at the same level as new resin, which is called virgin pellets or virgin film.

[0098] For example, recovered polyamide resin fluff can be melt-extruded at 200-300°C using an extruder, and recycled pellets made of polyamide resin can be produced using known methods such as the strand-cut method or the hot-cut method. Similarly, recovered polyolefin resin fluff can be melt-extruded at 100-250°C to produce recycled pellets made of polyolefin resin.

[0099] In this specification, the polyamide resin fluff recovered through the process described above, and the recycled pellets and films made using said fluff, may be referred to as polyamide resin (R1). Similarly, the polyolefin resin fluff recovered through the process described above, and the recycled pellets and films made using said fluff, may be referred to as polyolefin resin (R2).

[0100] <Preferred Embodiment> The method for separating and recovering the laminate according to this embodiment includes steps (1) to (5) described above. Each step may be performed only once or multiple times. In particular, it is preferable to perform the washing step (3) and the centrifugal separation step (4) multiple times. This makes it possible to recover resin of higher purity. When the washing step (3) is performed multiple times, the rinsing agent used for washing may be the same or different each time.

[0101] In a preferred embodiment, the process has steps (1), (2), (4), (3), (4), and (5) in this order. It is preferable to include a centrifugal separation step (4) after the stripping step (2) and the washing step (3), so that the stripping agent and rinsing agent used in each step can be removed before proceeding to the next step.

[0102] In this embodiment, steps (1), (2), (4), (3), (4), (3), (4), and (5) may be in this order. By providing the washing step (3) multiple times, a resin of higher purity can be recovered.

[0103] (color difference) In this embodiment, the substrate layer and sealant layer recovered through the process described above have minimal ink residue, and as a result, the color difference before and after separation and recovery is suppressed. Specifically, it is preferable that the substrate layer (polyamide resin (R1)) recovered in this embodiment shows less change in color difference compared to the polyamide resin before the stripping treatment. The color difference is measured by the reflection method in accordance with JIS Z8722 (2009). When measuring the color difference, 0.30 g of the recovered substrate layer or sealant layer fragments is packed into a quartz cell with a diameter of 35 mm and a height of 14 mm for measurement.

[0104] The brightness L* value of the polyamide resin (R1) is preferably 50.0 or higher, more preferably 55.0 or higher, even more preferably 60.0 or higher, and particularly preferably exceeding 65.0. Furthermore, the absolute value of the difference in brightness L* before and after separation and recovery (ΔL*) is preferably 35.0 or less, more preferably 30.0 or less, and even more preferably 25.0 or less. Within the specified range for the brightness L* value of the polyamide resin (R1) and the change in brightness L* (ΔL*), the polyamide resin (R1) exhibits excellent design properties and can be reused as packaging film, etc., for the same purposes as the polyamide film before separation and recovery.

[0105] The color a* value (a*) of the polyamide resin (R1) is preferably between -7.0 and 5.0, more preferably between -6.0 and 4.0, and even more preferably between -4.0 and 2.0. If the a* value falls within this range, the polyamide resin (R1) has excellent design properties and can be reused as packaging film, etc., for the same purposes as the polyamide film before separation and recovery.

[0106] The absolute value (Δa*) of the difference in color a* before and after separation and recovery of the polyamide resin (R1) is preferably 3.8 or less, more preferably less than 3.5, and even more preferably less than 3.0. Within this range of Δa*, the polyamide resin (R1) has excellent design properties and can be reused as packaging film, etc., for the same purposes as the polyamide film before the release treatment.

[0107] The color b* value (b*) of the polyamide resin (R1) is preferably between -4.0 and 6.0, more preferably between -3.0 and 5.0, and even more preferably between -2.0 and 4.0. If the b* value falls within this range, the polyamide resin (R1) has excellent design properties and can be reused as packaging film, etc., for the same purposes as the polyamide film before separation and recovery.

[0108] The absolute value (Δb*) of the difference in color b* before and after separation and recovery of the polyamide resin (R1) is preferably 10.0 or less, more preferably 5.0 or less, even more preferably less than 3.0, and particularly preferably less than 2.5. Within this range of Δb*, the polyamide resin (R1) has excellent design properties and can be reused as packaging film, etc., for the same purposes as the polyamide film before the release treatment.

[0109] In this embodiment, it is preferable that the recovered base material layer (polyamide resin (R1)) shows less change in the yellow index (YI), measured by the reflection method in accordance with JIS K7373 (2006), compared to the polyamide film before the separation and recovery treatment. The absolute value of the difference in the yellow index YI (ΔYI) before and after the separation and recovery of the polyamide resin (R1) is preferably less than 10.0, more preferably less than 7.0, and even more preferably less than 5.0. Within this range of ΔYI, the polyamide resin (R1) has excellent design properties and can be reused as a packaging film, etc., for the same purposes as the polyamide film before the release treatment.

[0110] Similarly, it is preferable that the sealant layer (polyolefin resin (R2)) recovered in this embodiment shows less change in color difference compared to the polyolefin resin before the stripping treatment. The method for measuring the color difference is the same as the method for measuring the color difference of the substrate layer (polyamide resin (R1)).

[0111] The brightness L* value of the polyolefin resin (R2) is preferably 50.0 or higher, more preferably 55.0 or higher, even more preferably 60.0 or higher, even more preferably 65.0 or higher, and particularly preferably exceeding 70.0. Furthermore, the absolute value of the difference in brightness L* before and after separation and recovery (ΔL*) is preferably 35.0 or less, more preferably 30.0 or less, and even more preferably 25.0 or less. Within the range of the brightness L* value of the polyolefin resin (R2) and the change in brightness L*, ΔL*, the polyolefin resin (R2) has excellent design properties and can be reused as packaging film, etc., for the same purposes as the polyolefin film before peeling treatment.

[0112] The color value (a*) of the polyolefin resin (R2) is preferably between -7.0 and 3.0, more preferably between -6.0 and 2.0, and even more preferably between -5.0 and 1.0. Within this range, the polyolefin resin (R2) has excellent design properties and can be reused as packaging film, etc., for the same purposes as the polyolefin film before release treatment.

[0113] The absolute value (Δa*) of the difference in color a* before and after separation and recovery of the polyolefin resin (R2) is preferably 4.0 or less, more preferably 3.5 or less, even more preferably less than 3.0, and particularly preferably less than 2.5. Within this range of Δa*, the polyolefin resin (R2) has excellent design properties and can be reused as packaging film, etc., for the same purposes as the polyolefin film before the release treatment.

[0114] The color b* value (b*) of the polyolefin resin (R2) is preferably between -5.0 and 5.0, more preferably between -4.0 and 4.0, and even more preferably between -3.0 and 3.0. If the b* value falls within this range, the polyolefin resin (R2) has excellent design properties and can be reused as packaging film, etc., for the same purposes as the polyolefin film before release treatment.

[0115] The absolute value (Δb*) of the difference in color b* before and after separation and recovery of the polyolefin resin (R2) is preferably 10.0 or less, more preferably 5.0 or less, even more preferably less than 3.0, and still more preferably less than 2.5. If Δb* is within this range, the polyolefin resin (R2) has excellent design properties and can be reused as packaging film, etc., for the same purposes as the polyolefin film before the peeling treatment.

[0116] In this embodiment, it is preferable that the recovered sealant layer (polyolefin resin (R2)) shows less change in the yellow index (YI), measured by the reflection method in accordance with JIS K7373 (2006), compared to the sealant layer (C) before the separation and recovery treatment. The absolute value (ΔYI) of the difference in the yellow index YI before and after the separation and recovery of the polyolefin resin (R2) is preferably less than 9.0, more preferably 8.5 or less, and even more preferably less than 8.0. Within this range of ΔYI, the polyolefin resin (R2) has excellent design properties and can be reused as packaging film, etc., for the same purposes as the polyolefin film before the peeling treatment. [Examples]

[0117] The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

[0118] <Raw materials and equipment> The abbreviations, components, and physical properties of the resins, release agents, and rinse agents used in the examples and comparative examples are as follows. The apparatus used in the examples and comparative examples is also as follows.

[0119] Substrate layer: Polyamide 6 film (manufactured by HYOSUNG, biaxially oriented film, 20 μm thick) Printing layer (A): Rio Alpha (manufactured by Toyo Ink Co., Ltd.) Adhesive resin layer (B): Contains 90 parts by mass of DIC Dry LX-500 (manufactured by DIC Corporation) and 10 parts by mass of KW-75(20) (manufactured by DIC Corporation) as a curing agent. Sealant layer (C): Linear low-density polyethylene SE620A (manufactured by Tamapoly Co., Ltd.)

[0120] The stripping agent (P) contains 70% by mass of N-methyl-2-pyrrolidone as a polar solvent, 5% by mass of dimethylbis(2-hydroxyethyl)ammonium hydroxide as a quaternary ammonium salt, and 25% by mass of water. Rinse agent (Q1): Contains 70% by mass of N-methyl-2-pyrrolidone as a polar solvent, 5% by mass of dimethylbis(2-hydroxyethyl)ammonium hydroxide as a quaternary ammonium salt, and 25% by mass of water. Rinse agent (Q2): Contains 0.2% by mass of polyethylene glycol monooleate and 99.8% by mass of water as surfactants.

[0121] Grinding equipment: Washing and grinding equipment PF-2000 manufactured by Nippon Seam Co., Ltd. Stripping and deinking device: Nippon Seam-made vortex water flow type washing and sorting device (500L stirring tank capacity, hot water temperature control mechanism, stirrer with multiple stirring blades, and multiple baffles on the wall of the stirring tank) Dehydration equipment: Washing and dehydrating machine manufactured by Nippon Seam Co., Ltd. Separation equipment: 500 mL beaker, magnetic stirrer

[0122] (Example 1) <Method for manufacturing laminates> Printing ink was prepared by diluting Rio Alpha (manufactured by Toyo Ink Co., Ltd.) with a mixed solvent of ethyl acetate, isopropyl alcohol, and methyl ethyl ketone. The viscosity of the printing ink needs to be finely adjusted for each color depending on the design and function of the printed material, but it was generally diluted with the mixed solvent to achieve a viscosity of 13-16 seconds on a Zahn cup #3. The printing ink was printed onto a substrate layer (polyamide 6 film, 20 μm thick) using a gravure printing press equipped with a gravure plate with a plate depth of 30 μm, and dried with hot air at 50°C to obtain a laminate consisting of a substrate layer (polyamide 6) / printed layer (A). Next, an adhesive resin layer (B) was applied to the printed layer (A) of the obtained laminate using a dry laminating machine, with a drying amount of approximately 3 g / m². 2 The material was applied and dried to achieve the desired result. Subsequently, a sealant layer (C) was bonded to obtain a laminate consisting of a base layer (polyamide 6), a printed layer (A), an adhesive resin layer (B), and a sealant layer (C).

[0123] <Laminate crushing and fluff (F1) fabrication (Process (1))> Using a wet crushing device manufactured by Nippon Seam (equipped with a 5mm diameter circular screen), the laminated material was crushed while water at room temperature was introduced. Only materials that could pass through the screen opening were selected to obtain the laminated fluff (F1).

[0124] <Laminate exfoliation and fluff (F2) fabrication (Process (2))> A release agent (P) was added to the stirring tank of a spiral water flow type washing and sorting apparatus manufactured by Nippon Seam (stirring tank capacity 500L, stirrer with multiple stirring blades, and multiple baffles on the wall of the stirring tank), and the temperature of the release agent (P) was adjusted to 80°C using a hot water temperature control mechanism provided in the stirring tank. Next, a laminate fluff (F1) was added to the stirring tank and immersed, and the release agent (P) and the laminate fluff (F1) were mixed, fluidized, and stirred for 3 hours using the stirrer provided in the stirring tank. This dissolved the printed layer (A) and the adhesive resin layer (B), and by peeling off each layer, the base layer and sealant layer (C) were separated from the laminate, and a fluff (F2) was obtained in which the resin (R1) constituting the base layer and the resin (R2) constituting the sealant layer (C) were mixed. In the preparation of fluff (F2), 475 kg of release agent (P) and 25 kg of laminated fluff (F1) were used, so that the mass ratio of the laminate to the total weight of 500 kg was 5% by mass. At this time, the stirring power value expressed per unit volume, obtained by subtracting the power required for dry running from the power required for stirring, was 13.0 W / m 3 The stirring power values ​​were obtained by taking a 1-minute moving average to remove noise components. Furthermore, throughout the series of experiments, the stirring power values ​​tended to be roughly proportional to the fifth power of the rotational speed.

[0125] <Removal of release agent (centrifugation) and preparation of fluff (F3) (step (4))> Using a washing and dewatering machine manufactured by Nippon Seam, the release agent (P) remaining in the fluff (F2) obtained in the above process was removed by centrifugal separation to obtain fluff (F3) in which resin (R1) and resin (R2) were mixed. The fluff (F2) was loaded into the washing and dewatering machine by manual batch processing.

[0126] <Cleaning of the laminate and fabrication of fluff (F4) (Process (3))> A swirling water flow type washing and sorting device (500L capacity) manufactured by Nippon Seam was used. Rinse agent (Q1) was added to the stirring tank, and fluff (F3), which was a mixture of resin (R1) and resin (R2), was added and immersed. Using the stirrer provided in the stirring tank, the rinse agent (Q1) and fluff (F3) were mixed, fluidized, and stirred for 10 minutes to wash off the release agent (P) adhering to the surface of the fluff. In this way, fluff (F4), which was a mixture of resin (R1) and resin (R2), was obtained. In preparing fluff (F4), 475 kg of rinse agent (Q1) and 25 kg of fluff (F3) were used, so that the mass ratio of fluff (F3) was 5% of the total weight of 500 kg.

[0127] <Removal of rinse agent (centrifugation) and preparation of fluff (F5) (step (4))> Using a washing and dewatering machine manufactured by Nippon Seam, the rinse agent (Q1) remaining in the fluff (F4) obtained in the above process was removed by centrifugal separation, and a fluff (F5) in which resin (R1) and resin (R2) were mixed was obtained. The fluff (F4) was loaded into the washing and dewatering machine by manual batch processing.

[0128] <Cleaning of the laminate and fabrication of fluff (F6) (Process (3))> In a swirling water flow type washing and sorting device (500L capacity) manufactured by Nippon Seam, rinse agent (Q2) was added to the stirring tank, and fluff (F5), which was a mixture of resin (R1) and resin (R2), was added and immersed. Using the stirrer provided in the stirring tank, the rinse agent (Q2) and fluff (F5) were mixed, fluidized, and stirred for 10 minutes to wash off the rinse agent (Q1) adhering to the surface of the fluff, and fluff (F6), which was a mixture of resin (R1) and resin (R2), was obtained. In the preparation of fluff (F6), 475 kg of rinse agent (Q2) and 25 kg of fluff (F5) were used, so that the mass ratio of the laminate was 5% by mass to a total weight of 500 kg.

[0129] <Removal of rinse agent (centrifugation) and preparation of fluff (F7) (step (4))> Using a washing and dewatering machine manufactured by Nippon Seam, the rinse agent (Q2) remaining in the fluff (F6) obtained in the above process was removed by centrifugal separation to obtain fluff (F7) in which resin (R1) and resin (R2) were mixed. The fluff (F6) was loaded into the washing and dewatering machine by manual batch processing.

[0130] <Separation of the base layer and production of fluffs (F8) made only of resin (R1) and fluffs (F9) made only of resin (R2) (Step (5))> 20g of fluff (F7), a mixture of resin (R1) and resin (R2), was placed in a 500mL beaker, and 500mL of distilled water was added. This mixture was stirred with a magnetic stirrer using a stirring bar for 30 seconds, then the stirring was stopped and the mixture was allowed to stand. Resin (R2) suspended in the water was collected by scooping it up with a net. Resin (R1) that settled in the water was collected by filtration. Fluff (F8) is a fluff made of resin (R1) (resin derived from the base layer), and fluff (F9) is a fluff made of resin (R2) (resin derived from the sealant layer).

[0131] (Example 2) Fluffs (F8) and (F9) were obtained in the same manner as in Example 1, except that the above-mentioned <removal of rinse agent (centrifugation) and preparation of fluff (F7) (step (4))> were not performed.

[0132] (Example 3) Fluffs (F8) and (F9) were obtained in the same manner as in Example 1, except that the above-mentioned <cleaning of the laminate and preparation of fluff (F6) (step (3))> and <removal of rinsing agent (centrifugation) and preparation of fluff (F7) (step (4))> were not performed.

[0133] (Example 4) Fluffs (F8) and (F9) were obtained in the same manner as in Example 1, except that the above-mentioned steps of <removal of rinse agent (centrifugation) and preparation of fluff (F5) (step (4))>, <cleaning of laminate and preparation of fluff (F6) (step (3))>, and <removal of rinse agent (centrifugation) and preparation of fluff (F7) (step (4))> were not performed.

[0134] (Example 5) In the above-described <Laminated material release and preparation of fluff (F2) (Step (2))>, 450 kg of release agent (P) and 50 kg of laminated fluff (F1) were used so that the mass ratio of the laminate was 10% by mass of the total weight of 500 kg. In the <Laminated material cleaning and preparation of fluff (F4) (Step (3))>, 450 kg of rinse agent (Q1) and 50 kg of fluff (F3) were used so that the mass ratio of the laminate was 10% by mass of the total weight of 500 kg. In the <Laminated material cleaning and preparation of fluff (F6) (Step (3))>, 450 kg of rinse agent (Q2) and 50 kg of fluff (F5) were used so that the mass ratio of the laminate was 10% by mass of the total weight of 500 kg. Fluff (F8) and fluff (F9) were obtained in the same manner as in Example 1, except that the stirring conditions in each step were as described in Table 1.

[0135] (Example 6) In the above-described <Laminated material release and preparation of fluff (F2) (Step (2))>, 450 kg of release agent (P) and 50 kg of laminated fluff (F1) were used so that the mass ratio of the laminate was 10% by mass of the total weight of 500 kg. In the <Laminated material cleaning and preparation of fluff (F4) (Step (3))>, 450 kg of rinse agent (Q1) and 50 kg of fluff (F3) were used so that the mass ratio of the laminate was 10% by mass of the total weight of 500 kg. In the <Laminated material cleaning and preparation of fluff (F6) (Step (3))>, 450 kg of rinse agent (Q2) and 50 kg of fluff (F5) were used so that the mass ratio of the laminate was 10% by mass of the total weight of 500 kg. Fluff (F8) and fluff (F9) were obtained in the same manner as in Example 2, except that the stirring conditions in each step were as described in Table 1.

[0136] (Example 7) In the above-described <Laminated structure peeling and preparation of fluff (F2) (Step (2))>, 450 kg of peeling agent (P) and 50 kg of laminated fluff (F1) were used so that the mass ratio of the laminate was 10% by mass of the total weight of 500 kg. In the <Laminated structure washing and preparation of fluff (F4) (Step (3))>, 450 kg of rinsing agent (Q1) and 50 kg of fluff (F3) were used so that the mass ratio of the laminate was 10% by mass of the total weight of 500 kg. Fluffs (F8) and (F9) were obtained in the same manner as in Example 3, except that the stirring conditions in each step were as described in Table 1.

[0137] (Example 8) In the above-described <Laminated structure peeling and preparation of fluff (F2) (Step (2))>, 450 kg of peeling agent (P) and 50 kg of laminated fluff (F1) were used so that the mass ratio of the laminate was 10% by mass of the total weight of 500 kg. In the <Laminated structure washing and preparation of fluff (F4) (Step (3))>, 450 kg of rinsing agent (Q1) and 50 kg of fluff (F3) were used so that the mass ratio of the laminate was 10% by mass of the total weight of 500 kg. Fluffs (F8) and (F9) were obtained in the same manner as in Example 4, except that the stirring conditions in each step were as described in Table 1.

[0138] (Example 9) In the above-described <Laminated structure peeling and preparation of fluff (F2) (Step (2))>, 425 kg of peeling agent (P) and 75 kg of laminated fluff (F1) were used so that the mass ratio of the laminate was 15% by mass of the total weight of 500 kg. In the <Laminated structure washing and preparation of fluff (F4) (Step (3))>, 425 kg of rinsing agent (Q1) and 75 kg of fluff (F3) were used so that the mass ratio of the laminate was 15% by mass of the total weight of 500 kg. In the <Laminated structure washing and preparation of fluff (F6) (Step (3))>, 425 kg of rinsing agent (Q2) and 75 kg of fluff (F5) were used so that the mass ratio of the laminate was 15% by mass of the total weight of 500 kg. Fluff (F8) and fluff (F9) were obtained in the same manner as in Example 1, except that the stirring conditions in each step were as described in Table 2.

[0139] (Example 10) In the above-described <Laminated material release and preparation of fluff (F2) (Step (2))>, 425 kg of release agent (P) and 75 kg of laminated fluff (F1) were used so that the mass ratio of the laminate was 15% by mass of the total weight of 500 kg. In the <Laminated material cleaning and preparation of fluff (F4) (Step (3))>, 425 kg of rinse agent (Q1) and 75 kg of fluff (F3) were used so that the mass ratio of the laminate was 15% by mass of the total weight of 500 kg. In the <Laminated material cleaning and preparation of fluff (F6) (Step (3))>, 425 kg of rinse agent (Q2) and 75 kg of fluff (F5) were used so that the mass ratio of the laminate was 15% by mass of the total weight of 500 kg. Fluff (F8) and fluff (F9) were obtained in the same manner as in Example 2, except that the stirring conditions in each step were as described in Table 2.

[0140] (Example 11) In the above-described <Laminated structure peeling and preparation of fluff (F2) (Step (2))>, 425 kg of peeling agent (P) and 75 kg of laminated fluff (F1) were used so that the mass ratio of the laminate was 15% by mass of the total weight of 500 kg. In the <Laminated structure washing and preparation of fluff (F4) (Step (3))>, 425 kg of rinsing agent (Q1) and 75 kg of fluff (F3) were used so that the mass ratio of the laminate was 15% by mass of the total weight of 500 kg. Fluffs (F8) and (F9) were obtained in the same manner as in Example 3, except that the stirring conditions in each step were as described in Table 2.

[0141] (Example 12) In the above-described <Laminated structure peeling and preparation of fluff (F2) (Step (2))>, 425 kg of peeling agent (P) and 75 kg of laminated fluff (F1) were used so that the mass ratio of the laminate was 15% by mass of the total weight of 500 kg. In the <Laminated structure washing and preparation of fluff (F4) (Step (3))>, 425 kg of rinsing agent (Q1) and 75 kg of fluff (F3) were used so that the mass ratio of the laminate was 15% by mass of the total weight of 500 kg. Fluffs (F8) and (F9) were obtained in the same manner as in Example 4, except that the stirring conditions in each step were as shown in Table 2.

[0142] (Comparative Example 1) Fluffs (F8) and (F9) were obtained in the same manner as in Example 1, except that the above-mentioned steps of <cleaning the laminate and preparing fluff (F4) (step (3))>, <removal of rinsing agent (centrifugation) and preparation of fluff (F5) (step (4))>, <cleaning the laminate and preparation of fluff (F6) (step (3))>, and <removal of rinsing agent (centrifugation) and preparation of fluff (F7) (step (4))> were not performed.

[0143] (Comparative Example 2) Fluffs (F8) and (F9) were obtained in the same manner as in Example 1, except that the above-mentioned steps of <removal of release agent and preparation of fluff (F3) (step (4))>, <cleaning of laminate and preparation of fluff (F4) (step (3))>, <removal of rinse agent (centrifugation) and preparation of fluff (F5) (step (4))>, <cleaning of laminate and preparation of fluff (F6) (step (3))>, and <removal of rinse agent (centrifugation) and preparation of fluff (F7) (step (4))> were not performed.

[0144] (Comparative Example 3) Fluffs (F8) and (F9) were obtained in the same manner as in Example 5, except that the above-mentioned steps of <Washing the laminate and preparing fluff (F4) (step (3))>, <Removal of rinsing agent (centrifugation) and preparing fluff (F5) (step (4))>, <Washing the laminate and preparing fluff (F6) (step (3))>, and <Removal of rinsing agent (centrifugation) and preparing fluff (F7) (step (4))> were omitted, and the stirring conditions in <Delamination of the laminate and preparing fluff (F2) (step (2))> were set to the conditions described in Table 3.

[0145] (Comparative Example 4) Fluffs (F8) and (F9) were obtained in the same manner as in Example 5, except that the above-mentioned steps of <Removal of release agent and preparation of fluff (F3) (step (4))>, <Washing of laminate and preparation of fluff (F4) (step (3))>, <Removal of rinsing agent (centrifugation) and preparation of fluff (F5) (step (4))>, <Washing of laminate and preparation of fluff (F6) (step (3))>, and <Removal of rinsing agent (centrifugation) and preparation of fluff (F7) (step (4))> were omitted, and the stirring conditions in <Laminate peeling and preparation of fluff (F2) (step (2))> were set to the conditions described in Table 3.

[0146] (Comparative Example 5) Fluffs (F8) and (F9) were obtained in the same manner as in Example 9, except that the above-mentioned steps of <Washing the laminate and preparing fluff (F4) (step (3))>, <Removal of rinsing agent (centrifugation) and preparing fluff (F5) (step (4))>, <Washing the laminate and preparing fluff (F6) (step (3))>, and <Removal of rinsing agent (centrifugation) and preparing fluff (F7) (step (4))> were omitted, and the stirring conditions in <Delamination of the laminate and preparing fluff (F2) (step (2))> were set to the conditions described in Table 3.

[0147] (Comparative Example 6) Fluffs (F8) and (F9) were obtained in the same manner as in Example 9, except that the above-mentioned steps of <Removal of release agent and preparation of fluff (F3) (step (4))>, <Washing of laminate and preparation of fluff (F4) (step (3))>, <Removal of rinsing agent (centrifugation) and preparation of fluff (F5) (step (4))>, <Washing of laminate and preparation of fluff (F6) (step (3))>, and <Removal of rinsing agent (centrifugation) and preparation of fluff (F7) (step (4))> were omitted, and the stirring conditions in <Laminate peeling and preparation of fluff (F2) (step (2))> were set to the conditions described in Table 3.

[0148] (Comparative Example 7) In Example 5, the above-mentioned steps of <Removal of release agent and preparation of fluff (F3) (step (4))>, <Washing of laminate and preparation of fluff (F4) (step (3))>, <Removal of rinse agent (centrifugation) and preparation of fluff (F5) (step (4))>, <Washing of laminate and preparation of fluff (F6) (step (3))>, and <Removal of rinse agent (centrifugation) and preparation of fluff (F7) (step (4))> were omitted, and the stirring conditions in <Laminate peeling and preparation of fluff (F2) (step (2))> were set to the conditions listed in Table 3. The stirring power value was 4.8 w / m 3 Only a certain amount could be obtained, and it was not possible to mix and stir the laminate fluff (F1) into the release agent (P).

[0149] <Measurement and Evaluation> <Agitation power value> The power was measured when a laminate or peeled layer was added to a release agent (P) or rinse agent (Q1, Q2) and the stirring blade was rotated. This power was then subtracted from the power measured during dry running (which had been measured beforehand), and the difference was divided by the volume of the mixture of release agent and laminate added to calculate the power.

[0150] <Liquid content> 10g of the fluff obtained in each step, in which the dehydrated resin (R1) and resin (R2) were mixed, was weighed out, its weight recorded, and then placed in a 500mL beaker and washed several times with 2-propanol. The washed fluff was placed in a dryer set to 80°C for 3 hours for pre-drying, and then vacuum-dried in a vacuum dryer set to 90°C for 18 hours. The weight of the dried fluff was measured, and the liquid content was calculated from the weight of the fluff after dehydrated treatment and the weight of the fluff after drying.

[0151] <Evaluation of separated and recovered material (Fluff F8: substrate layer)> <Color difference> The obtained substrate layer fluff (F8) was packed into a quartz cell, and the color difference was measured by the reflectance method using a Suga Test Instruments colorimeter in accordance with JIS Z8722 (2009). Colorimeter: Suga Test Instruments Co., Ltd. Color Meter, Model SM-T Quartz cell size: 35mm diameter, 14mm height Filling amount: 0.30g Measurement standard: Measurement is performed excluding specular reflection, based on the geometric conditions of JIS Z8722. Measurement conditions: C light source 2° field of view reflection Measurement hole diameter: Φ30mm The results measured under the above conditions were evaluated according to the following criteria. (L*) ○: L* exceeds 65.0 △: L* is between 50.0 and 65.0 ×: L* is less than 50.0 (a*) The color difference was measured for the substrate layer before it was formed into a laminate under the same conditions as above (reference example), and the absolute value (Δa*) of the difference between the a* value of the substrate layer before it was formed into a laminate and the a* value of the separated and recovered substrate layer was calculated and evaluated according to the following criteria. ○: Δa* is less than 3.0 △: Δa* is 3.0 or greater, but less than 3.5. ×:Δa*3.5 or more (b*) The color difference was measured for the substrate layer before it was formed into a laminate under the same conditions as described above (reference example). The absolute value (Δb*) of the difference between the b* value of the substrate layer before it was formed into a laminate and the b* value of the separated and recovered substrate layer was calculated and evaluated according to the following criteria. ○: Δb* is less than 2.5 △: Δb* is 2.5 or greater, and less than 3.0 ×: Δb* is 3.0 or greater

[0152] <Yellow Index (YI)> The obtained substrate layer fluff (F8) was packed into a quartz cell, and the yellow index was measured by reflection using a Suga Test Instruments colorimeter, model SM-T, in accordance with JIS K7373 (2006), and evaluated according to the following criteria. The yellow index was measured for the substrate layer before it was formed into a laminate under the same conditions as above (reference example). The absolute value of the difference between the YI value of the substrate layer before it was formed into a laminate and the YI value of the separated and recovered substrate layer (ΔYI) was calculated and evaluated according to the following criteria. ○: ΔYI is less than 5.0 △: ΔYI is 5.0 or greater, but less than 10.0 ×: ΔYI is 10.0 or greater

[0153] <Evaluation of separated and recovered material (Fluff F9: sealant layer (C))> <Color difference> The obtained fluff (F9) of the sealant layer was packed into a quartz cell, and the color difference was measured by the reflectance method using a Suga Test Instruments colorimeter in accordance with JIS Z8722 (2009). Colorimeter: Suga Test Instruments Co., Ltd. Color Meter, Model SM-T Quartz cell size: 35mm diameter, 14mm height Filling amount: 1.35g Measurement standard: Measurement is performed excluding specular reflection, based on the geometric conditions of JIS Z8722. Measurement conditions: C light source 2° field of view reflection Measurement hole diameter: Φ30mm The results measured under the above conditions were evaluated according to the following criteria. (L*) 〇: L* exceeds 70.0 △: L* is 60.0 or higher, and 70.0 or lower. ×: L* is less than 60.0 (a*) The color difference of the sealant layer (C) before it was formed into the laminate was measured under the same conditions as above (reference example), and the absolute value (Δa*) of the difference between the a* value of the sealant layer (C) before it was formed into the laminate and the a* value of the separated and recovered sealant layer (C) was calculated and evaluated according to the following criteria. ○: Δa* is less than 2.5 △: Δa* is 2.5 or greater, but less than 3.0. ×: Δa* exceeds 3.0 (b*) The color difference of the sealant layer (C) before it was formed into the laminate was measured under the same conditions as above (reference example), and the absolute value (Δb*) of the difference between the b* value of the sealant layer (C) before it was formed into the laminate and the b* value of the separated and recovered sealant layer (C) was calculated and evaluated according to the following criteria. ○: Δb* is less than 2.5 △: Δb* is 2.5 or greater, and less than 3.0 ×: Δb* exceeds 3.0

[0154] <Yellow Index (YI)> The obtained substrate layer fluff (F9) was packed into a quartz cell, and the yellow index was measured by reflection using a Suga Test Instruments colorimeter, model SM-T, in accordance with JIS K7373 (2006), and evaluated according to the following criteria. The yellow index was measured for the sealant layer (C) before it was formed into the laminate under the same conditions as above (reference example). The absolute value of the difference (ΔYI) between the YI value of the sealant layer (C) before it was formed into the laminate and the YI value of the separated and recovered sealant layer (C) was calculated and evaluated according to the following criteria. ○: ΔYI is less than 8.0 △: ΔYI is 8.0 or greater and less than 9.0 ×: ΔYI is 9.0 or higher

[0155] [Table 1]

[0156] [Table 2]

[0157] [Table 3]

Claims

1. A base layer and A method for separating and recovering a laminate, comprising a laminate consisting of two or more layers including at least one layer selected from the group consisting of a printed layer (A), an adhesive resin layer (B), and a sealant layer (C), wherein at least the substrate layer is separated and recovered. The process comprises the following steps (1), (2), (3), (4), and (5): (2) In step (2), the total volume of the laminate and release agent (P) is 1 m³. ３ The stirring power value per unit (the power used for stirring minus the power used for dry running) is 10 W / m². ３ The above describes the method for separating and recovering the laminate; (1) Step of crushing the laminate (2) A step of peeling off each layer of the laminate using an alkaline release agent (P) containing a polar solvent. (3) A step of washing the peeled layer with a rinse agent (Q) containing a polar solvent and / or a surfactant. (4) A step of centrifuging the release agent and / or rinsing agent remaining on the layer fragments peeled off in the previous step using a separator. (5) A step of separating the layer fragments that were peeled off in the previous step.

2. The method for separating and recovering the laminate according to claim 1, wherein the method for separating and recovering the laminate comprises steps (1), (2), (4), (3), (4), and (5) in this order, and the temperature of the release agent (P) in step (2) is 70°C or higher and 100°C or lower.

3. In step (3), the total volume of the peeled layer and the rinse agent (Q) is 1 m³. ３ The stirring power value per unit (the power used for stirring minus the power used for dry running) is 10 W / m². ３ The above describes the method for separating and recovering a laminate according to claim 1.

4. The method for separating and recovering a laminate according to claim 1, wherein in step (2), the mass ratio of the laminate to the total mass of the release agent (P) and the laminate is 3% by mass or more and 20% by mass or less.

5. The laminate includes a printed layer (A), The method for separating and recovering a laminate according to claim 1, wherein the printed layer (A) comprises at least one resin selected from the group consisting of acrylic resins, polyurethane resins, polyester resins, and polyamide resins, and a pigment.

6. The laminate includes an adhesive resin layer (B), The method for separating and recovering a laminate according to claim 1, wherein the adhesive resin layer (B) comprises at least one selected from the group consisting of urethane resin, ester resin, epoxy resin, and acrylic resin.

7. The method for separating and recovering a laminate according to claim 1, wherein the base layer comprises at least one selected from the group consisting of polyester resins, polyolefin resins, and polyamide resins.

8. The method for separating and recovering a laminate according to claim 7, wherein the base layer contains a polyamide resin.

9. The method for separating and recovering a laminate according to claim 1, wherein the absolute value Δb* of the difference between the b* value of the substrate layer separated and recovered by the method for separating and recovering the laminate and the b* value of the substrate layer before the peeling treatment is 2.5 or less.

10. The laminate includes a sealant layer (C), The method for separating and recovering a laminate according to claim 1, wherein the sealant layer (C) contains a polyolefin resin.

11. The method for separating and recovering a laminate according to claim 10, wherein the sealant layer (C) contains a polyethylene resin.

12. The method for separating and recovering the laminate includes separating and recovering the sealant layer (C), The method for separating and recovering a laminate according to claim 10, wherein the absolute value Δa* of the difference between the a* value of the sealant layer (C) separated and recovered by the method for separating and recovering the laminate and the a* value of the sealant layer (C) before the peeling treatment is less than 2.5.

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