Method for separating and recovering container and packaging materials

Abstract

The present invention provides a separation and recovery method that can efficiently separate the resin layer and the base material of a container or packaging material while suppressing entanglement between the resin layer and the base material in the peeling solution. [Solution] According to the present invention, a method for separating and recovering a container packaging material comprising a base layer and a thermoplastic resin layer bonded to the base layer by crushing the material and immersing it in a peeling solution, wherein the crushing of the container packaging material results in a width of 7 mm to 45 mm and an area of ​​49 mm 2 More than 2025mm 2 The following is a method for separating and recovering container and packaging materials, characterized by comprising: a crushing step of obtaining crushed material with an aspect ratio of 1:1 to 1:5; a peeling step of immersing the crushed material in a peeling solution with a specific gravity of 1.05 to 1.61; and a separation step of separating the material into a base layer and a resin layer.

Description

[Technical Field]

[0001] The present invention relates to a separation and recovery method for separating a base material layer and a thermoplastic resin layer of a container packaging material. [Background technology]

[0002] For food and pharmaceutical packaging, laminates are used, which are composites of multiple resin layers and metals, for aesthetic reasons and to protect the contents. For example, aluminum foil laminates, which are composites of aluminum foil and a thermoplastic resin layer, are used for aluminum packaging materials for pharmaceuticals and aluminum lids for yogurt containers. For transparent individual packaging of candy and other products, laminates are used, which are composites of polyethylene resin and other materials on a base material such as polyester film.

[0003] The base material is made of a rigid resin film or aluminum foil, chosen for its strength and puncture resistance. A thermoplastic resin layer, such as polyethylene, is then composited or laminated to preserve the freshness of the contents and prevent oxidation. In addition, printing or colored coatings are applied for aesthetic purposes and to indicate the contents.

[0004] However, with the recent rise in awareness of SDGs and the global environment, there is a demand for high recyclability in laminates including resin layers. However, the diverse combinations of materials and components, including the aforementioned resin layer, have been hindering the recycling of these laminates.

[0005] Therefore, various recycling methods are being considered in order to maintain the functionality of containers and packaging materials while also achieving a high degree of recyclability. For example, Japanese Patent Publication No. 2020-515655 (Patent Document 1) describes a method for separating the metal layer from the resin layer by using a separation fluid (separation solution) containing a mixture of water, short-chain carboxylic acid, phosphoric acid, and alkali metal hydroxide.

[0006] Furthermore, Japanese Patent Publication No. 2024-6854 (Patent Document 2) describes a method for separating and recovering laminates in which a laminate comprising a plastic substrate layer and a printed layer is immersed in a desorption liquid, and the printed layer components detached from the plastic substrate layer are desorbed such that the median diameter (D50) of the detached printed layer components on a volume basis is 1 μm or more, and the printed layer accounts for 0.01% or more by mass of the total mass of the desorption liquid, thereby suppressing the re-adhesion of the detached printed layer components to the substrate layer. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Special Publication No. 2020-515655 [Patent Document 2] Japanese Patent Publication No. 2024-6854 [Overview of the project] [Problems that the invention aims to solve]

[0008] However, the separation technique described in Patent Document 1 had the problem that even when using the peeling solution of Patent Document 1, the resin layer and aluminum foil constituting the container packaging material would become entangled, causing the aluminum foil to float together with the resin layer, making sufficient separation and recovery impossible. Furthermore, the separation technique described in Patent Document 2 had the problem that even when the container packaging material was detached such that the median diameter (D50) of the printed layer component based on volume was 1 μm or more, the printed layer would become too fine and simply float in the peeling solution, making it impossible to sufficiently separate the detached printed layer component from the plastic substrate layer vertically.

[0009] Therefore, the present invention aims to provide a separation and recovery method that can efficiently separate the resin layer and the base material layer of a container and packaging material while suppressing entanglement between the resin layer and the base material layer that constitute the container and packaging material in a peeling solution. [Means for solving the problem]

[0010] In order to solve the above problems, the inventors of the present invention have intensively studied the conditions related to the container packaging material such as the size for separating the resin layer and the base material layer of the container packaging material, and the conditions related to the stripping solution such as the composition. As a result, by controlling the crushing size of the container packaging material immersed in the stripping solution, the entanglement between the resin layer and the base material layer is suppressed, and by changing the specific gravity of the stripping solution, it has been found that the resin layer and the base material layer can be efficiently separated, and the present invention has been completed.

[0011] That is, according to the present invention, there is provided a method for separating and recovering a container packaging material including a base material layer and a thermoplastic resin layer adhered to the base material layer by crushing the container packaging material and immersing it in a stripping liquid to strip and separate it into the base material layer and the resin layer, wherein by crushing the container packaging material, a crushed product having a width of 7 mm or more and 45 mm or less, an area of 49 mm 2 or more and 2025 mm 2 or less, and an aspect ratio of 1:1 to 1:5 is obtained in a crushing step, the crushed product is immersed in a stripping solution having a specific gravity of 1.05 or more and 1.61 or less in a stripping step, and a separation step of separating by stripping into the base material layer and the resin layer is provided. A method for separating and recovering a container packaging material is provided.

[0012] In addition, in the separation and recovery method of the present invention, by using a stripping solution as shown below, the specific gravity of the stripping solution can be changed to facilitate the separation of the resin layer and the base material layer, and the reattachment of the stripped resin layer to the base material layer can be suppressed. Therefore, it is preferable. <Stripping solution (a)> In a stripping solution (a) containing at least one first acid selected from nitric acid and formic acid, one or more second acids selected from the group consisting of polyvalent carboxylic acids, hydroxy acids, polyvalent carboxylates and hydroxy carboxylates, and water, the content ratio of the first acid in the stripping solution (a) (mass%) divided by the content of the second acid in the stripping solution (a) (mass%) is a stripping solution (a) of 0.05 or more and 30 or less. <Stripping solution (b)> In the stripping solution (b) containing an ammonium salt composed of at least one of ammonium formate and ammonium acetate, one or more acids selected from the group consisting of nitric acid, sulfuric acid, phosphoric acid, formic acid and acetic acid, and water, the content ratio obtained by dividing the content (% by mass) of the ammonium salt in the stripping solution (b) by the content (% by mass) of the acid in the stripping solution (b) is 0.1 or more and 40.0 or less. The stripping solution (b), <Stripping solution (c)> Containing 1% by mass or more and 98% by mass or less of formic acid, 1% by mass or more and 98% by mass or less of a carboxylic acid ester composed of a formic acid ester having 9 or less carbon atoms and / or an acetic acid ester having 9 or less carbon atoms, 1% by mass or more and 90% by mass or less of water, and the sum of the contents of the formic acid and the carboxylic acid ester is 10% by mass or more and 99% by mass or less, and the sum of the contents of the formic acid, the carboxylic acid ester and water is 100% by mass or less. The stripping solution (c), <Stripping solution (d)> Containing a metal carboxylate, an acid and a polar solvent, the content of the metal carboxylate is 2% by mass or more and 50% by mass or less, and the pH at 25°C is 0.5 or more and 4 or less. The stripping solution (d), <Stripping solution (e)> The stripping solution (e) is an aqueous formic acid solution, or <Stripping solution (f)> The stripping solution (f) is an aqueous sodium hydroxide solution

[0013] In addition, in the separation and recovery method of the present invention, in the crushing step, in order to crush the container packaging material into a desired size, one or more methods selected from the group consisting of a cutting method, a sheet pelletizer method, a shredder method and a single-axis crushing method can be used.

Advantages of the Invention

[0014] According to the separation and recovery method of the present invention, while suppressing the entanglement between the resin layer and the base material layer constituting the container packaging material in the stripping solution, the resin layer and the base material layer of the container packaging material can be efficiently separated.

Brief Description of the Drawings

[0015] [Figure 1] This is a photograph showing the crushed specimen of Example 1 according to one embodiment of the present invention. [Figure 2] This is a photograph showing the crushed specimen of Example 16 according to one embodiment of the present invention. [Modes for carrying out the invention]

[0016] The following describes in detail a method for separating and recovering container and packaging materials according to one embodiment of the present invention. It should be noted that the present invention is not limited to the embodiments shown below, and various modifications are possible without departing from the technical spirit of the invention.

[0017] <Base material layer> In the present invention, the base material layer constituting the container packaging material is made of a heat-resistant material capable of withstanding heat sealing at 150°C to 250°C, such as aluminum foil, polyethylene terephthalate (PET), stretched polypropylene (OPP), cellophane, nylon, or paper. For example, the heat resistance of OPP can be achieved by stretching polypropylene resin to orient the crystals.

[0018] Among these materials, aluminum foil and PET, which do not contain water and have a specific gravity greater than 1, and therefore tend to settle in the separation solution, are more suitable for separation in this invention. Furthermore, the thickness of the base layer is not particularly limited as long as it is a material commonly used as a container or packaging material, and a thickness of 1 μm to 10 mm is preferably used.

[0019] <Thermoplastic resin layer> Thermoplastic resins (layers) used in containers and packaging materials include acrylic resins, polystyrene, ABS resins, vinyl chloride resins, vinyl acetate resins, polyethylene resins, unoriented polypropylene (CPP) resins, polyamide resins, polycarbonate, polyacetal, fluoropolymer resins, and blends of these resins, as well as copolymer resins and modified resins such as vinyl chloride-vinyl acetate copolymers, which include combinations of the monomers that make up these resins.

[0020] Among these resins, polyolefin resins such as polyethylene resin and unstretched polypropylene resin, which have a specific gravity of less than 1 and do not contain water, are more suitable for separation in the present invention because they easily float in the stripping solution.

[0021] The thermoplastic resin (layer) may be laminated on only one side of the substrate (layer), or on both sides. Furthermore, the thermoplastic resin (layer) may be a single layer, or multiple layers. The thickness of the thermoplastic resin layer is not particularly limited as long as it is a thickness commonly used for container and packaging materials; a thickness of 1 μm to 10 mm is preferably used.

[0022] <Containers and packaging materials> The container packaging material used in the present invention is a lid or other component for sealing or enclosing contents inside a container, and is a laminate comprising at least a base layer and a thermoplastic resin layer laminated on the base layer. The base layer is used to give the container packaging material rigidity and to provide strength, tear resistance, puncture resistance, etc., and may consist of one layer or two or more layers. Furthermore, when the container packaging material is used as a lid for a container as described above, the thermoplastic resin layer needs to be placed as the outermost layer in order to heat-seal the sealing surface that comes into contact with the container.

[0023] The base layer or the thermoplastic resin layer may be laminated by coating one of them, or by lamination via an adhesive or other adhesive. In addition, at least one of the base layer and the thermoplastic resin layer may be provided with an optional layer, such as a printed layer or a colored layer, and a primer coat or anchor coat may be applied to improve the adhesion between the colored layer, the base layer and the thermoplastic resin layer.

[0024] Any known method can be used to laminate a printed layer or a colored layer onto a substrate layer or a thermoplastic resin layer, or either of these. Examples include coating methods using coating agents such as roll coating, various gravure coatings, doctor blade coating, comma coater, spray coating, brush coating, spin coating method, bar coating method, flow coating method, dip coating method, or die coating method. Alternatively, a lamination method combining two or more of the above coating methods may be used. Furthermore, drying or heat treatment for reaction may be performed after coating.

[0025] Lamination methods are not particularly limited, but examples include dry lamination using two-component curing adhesives such as polyester urethane or polyester, co-extrusion, extrusion coating, extrusion lamination, heat sealing, or heat lamination using an anchor coating agent.

[0026] <Crushing process> In this invention, the crushing process involves a width of 7 mm to 45 mm and an area of ​​49 mm. 2 More than 2025mm 2 The following is a process for obtaining crushed material with an aspect ratio of 1:1 to 1:5. In other words, it can also be described as a process for crushing container packaging material to a specific size. Here, the specific size refers to the size of each piece, and it is not necessarily the case that all of the crushed material falls within the specified size range, but it is preferable that at least 50% by mass of the total crushed material falls within the specified size range. More preferably, it is particularly preferable that 75% by mass of the total crushed material falls within the specified size range.

[0027] In this invention, crushing refers to the process of crushing container packaging material into small pieces. The crushing method is not particularly limited, but can be selected from one or more methods such as cutting, sheet pelletizing, shredding, and uncoordinated crushing.

[0028] The cutting method, also known as the guillotine cutting method, can cut into square or rectangular pieces with an accuracy of ±0.3 mm. The guillotine blade can cut container packaging materials stacked up to a thickness of 100 mm using hydraulics. The sheet pelletizer takes the container packaging materials in stacks to a total thickness of about 1 mm, cuts the width direction of the container packaging materials with a fixed blade, cuts the length direction of the container packaging materials with a rotating blade, and finally cuts the container packaging materials into square or rectangular pieces.

[0029] The shredder system allows container packaging material to be fed in one sheet or up to 1 mm thick from a belt conveyor belt and cut into squares or rectangles using fixed blades. The single-shaft shredder allows container packaging material to be fed in stacks from a hopper to a total thickness of about 1 mm and shredded by rotating blades, repeatedly shredding and refeeding until it reaches a predetermined size.

[0030] The preferred shredding method ensures consistent shapes and dimensions, such as squares and rectangles, and, when shredding in layers, prevents the cut surfaces from crimping together. Therefore, manual cutting with a guillotine blade or an automatic continuous cutting method are preferred. Sheet pelletizers and shredders are also preferred as shredding methods for container packaging materials because they allow for sharp cutting with fixed blades. Furthermore, the uncoordinated shredding method is particularly suitable for shredding rigid container packaging materials, such as those using polyester film as a base material, as repeated shredding may cause bending.

[0031] In this invention, the crushed material obtained by crushing the container packaging material has a substantially geometric planar shape, a width of 7 mm to 45 mm, and an area of ​​49 mm². 2 More than 2025mm 2 The aspect ratio must be within the range of 1:1 to 1:5.

[0032] The term "roughly geometric planar shapes" here includes not only squares and rectangles, but also roughly triangles, roughly rectangular shapes, circles, stars, and irregular shapes that combine these. Roughly triangles and roughly rectangular shapes are not limited to triangles composed of three straight lines, such as equilateral triangles, isosceles triangles, and right triangles, or rectangles composed of four straight lines, such as squares, rectangles, rhombuses, and trapezoids, but also include shapes where one of the corners is rounded or missing, or where one of the sides is curved.

[0033] In this invention, the width and aspect ratio of the crushed material are defined using the Ferret minor axis and Ferret major axis, so that even irregularly shaped crushed material can be defined. Specifically, the crushed material of the container packaging is spread out on a plane, and a photograph of the planar field of view is taken. The size of the irregularly shaped crushed material is defined from the minor axis (Ferret minor axis) and major axis (Ferret major axis) of the equivalent ellipse that circumscribes the measurement target (container packaging material) in this binary image. That is, the width of the crushed material is determined by the Ferret minor axis, and the aspect ratio of the crushed material can be determined by the ratio of the Ferret minor axis to the Ferret major axis. The drawing of such an equivalent ellipse and the measurement of the Ferret minor axis and Ferret major axis can be performed using known image analysis software. For example, WinRoof2023 from Mitani Corporation can be suitably used as image analysis software.

[0034] The shape of the crushed material is preferably such that each interior angle is 90° or greater. For example, parts with interior angles of 90° or greater, such as the vertex angle of a triangle, are easily bent, and when bent, the bent portion remains in a state where the base material layer and the thermoplastic resin layer overlap and are sandwiched together even after peeling, making it difficult to separate the base material layer and the resin layer in the peeling process described later. Therefore, the shape of the container packaging material is preferably rectangular rather than approximately triangular.

[0035] The width dimension of the crushed material should be 7 mm or more and 45 mm or less. If the width of the crushed material is less than 7 mm, the crushed material is likely to be bent or folded. Therefore, the bent or folded crushed material is likely to trap air (bubbles) in the bent or folded part during stirring in the stripping solution, resulting in buoyancy and causing the base material layer and the thermally adhesive resin to float together, making it difficult to separate them from the resin layer. On the other hand, if the width of the crushed material exceeds 45 mm, the thermoplastic resin layer after peeling is likely to reattach to the base material layer while floating, making it difficult to separate and recover from the base material layer. Therefore, the width dimension of the crushed material is more preferably 15 mm or more and 35 mm or less, and even more preferably 15 mm or more and 20 mm or less.

[0036] The area of the crushed material is 49 mm 2 or more and 2025 mm 2 or less. According to Stokes' law, the terminal settling velocity is proportional to the square of the diameter of the crushed material when the crushed material is circular. Therefore, if the area is small, it becomes difficult to settle or float even if the specific gravity difference from the stripping solution exists. Therefore, if the area of the crushed material is less than 49 mm 2 , it becomes difficult to float and separate and recover the thermoplastic resin layer. On the other hand, if the area of the crushed material exceeds 2025 mm 2 , the thermoplastic resin layer after peeling is too large and contacts and gets entangled with the base material layer, resulting in the base material layer and the thermoplastic resin layer floating together and being unable to be separated. Therefore, the area of the crushed material is more preferably 49 mm 2 or more and 1125 mm 2 or less, and even more preferably 400 mm 2 or more and 1125 mm 2 or less.

[0037] The aspect ratio (width to length ratio) of the crushed material must be in the range of 1:1 to 1:5. If the aspect ratio of the crushed material exceeds 1:5, it becomes elongated, making it more prone to bending and folding. As a result, when crushed material that has bent or folded is stirred in the peeling solution, air (bubbles) is easily trapped in the bent or folded parts, creating buoyancy that causes the base material layer and thermoplastic resin layer to float together, making it difficult to separate the base material layer and the resin layer. From the viewpoint of suppressing the trapping of air (bubbles) in the crushed material, it is desirable that the width and length of the crushed material are close to each other, and therefore, an aspect ratio of the crushed material in the range of 1:1 to 1:2 is more preferable. In this invention, the shape and size of the crushed material within the above range after crushing can be controlled by adjusting the cutting interval, blade pitch, rotation speed, etc. during cutting.

[0038] <Peeling process> In the present invention, the peeling step is a process of immersing the crushed material in a peeling solution to separate the substrate layer from the thermoplastic resin layer. Therefore, the peeling solution needs to have the function of separating the substrate layer from the thermoplastic resin layer.

[0039] <Removal solution> Any peeling solution that can separate the base material layer and the thermoplastic resin layer of the container packaging material can be used in this invention. For example, any of the peeling solutions (a) to (f) shown below can be used.

[0040] · Stripping solution (a) The stripping solution (a) contains a first acid consisting of at least one of nitric acid and formic acid, one or more second acids selected from the group consisting of polycarboxylic acids, hydroxy acids, polycarboxylic acid salts and hydroxy salts, and water, wherein the content ratio obtained by dividing the content (mass%) of the first acid in the stripping solution (a) by the content (mass%) of the second acid in the stripping solution (a) is 0.05 or more and 30 or less.

[0041] The peeling solution (a) allows for the peeling of the resin layer from the laminate (container packaging material) while adjusting the peeling speed with the effect of the second acid, through the peeling effect of a first acid consisting of at least one of nitric acid and formic acid, and the protective effect of one or more second acids selected from the group consisting of polycarboxylic acids, hydroxy acids, polycarboxylic acid salts and hydroxy salts, on the substrate layer.

[0042] · Stripping solution (b) The stripping solution (b) contains an ammonium salt consisting of at least one of ammonium formate and ammonium acetate, one or more acids selected from the group consisting of nitric acid, sulfuric acid, phosphoric acid, formic acid, and acetic acid, and water, wherein the content ratio obtained by dividing the content (mass%) of the ammonium salt in the stripping solution (b) by the content (mass%) of the acid in the stripping solution (b) is 0.1 or more and 40.0 or less.

[0043] The peeling solution (b) can peel the resin layer from the laminate (container packaging material) while adjusting the peeling speed through the synergistic effect of the peeling effect of one or more acids selected from the group consisting of nitric acid, sulfuric acid, phosphoric acid, formic acid, and acetic acid, and the protective effect of the substrate layer by an ammonium salt consisting of at least one of ammonium formate and ammonium acetate.

[0044] · Stripping solution (c) The stripping solution (c) contains 1% to 98% by mass of formic acid, 1% to 98% by mass of carboxylic acid esters consisting of formic acid esters having 9 or fewer carbon atoms and / or acetate esters having 9 or fewer carbon atoms, 1% to 90% by mass of water, and the sum of the content of formic acid and the carboxylic acid esters is 10% to 99% by mass, and the sum of the content of formic acid, the carboxylic acid esters and water is 100% or less by mass.

[0045] In the peeling solution (c), the carboxylic acid ester in the solution penetrates into the resin layer in the crushed material, assisting in the peeling of the resin layer by formic acid, thereby easily separating the substrate layer from the resin layer.

[0046] · Stripping solution (d) The stripping solution (d) contains a metal carboxylate salt, an acid, and a polar solvent, wherein the content of the metal carboxylate salt is 2% by mass or more and 50% by mass or less, and the pH at 25°C is 0.5 or more and 4 or less.

[0047] In the stripping solution (d), a carboxylic acid is produced by the reaction of a carboxylic acid metal salt and an acid in solution, and the resulting carboxylic acid functions to strip the substrate layer from the resin layer.

[0048] · Stripping solution (e) The release solution (e) is an aqueous formic acid solution, and in the release solutions (a) to (d) above, the water and formic acid in the partially applied aqueous formic acid solution function to separate the resin layer from the substrate layer.

[0049] · Stripping solution (f) The release solution (f) is an aqueous sodium hydroxide solution, which functions to separate the resin layer from the substrate layer by breaking the bonds at the interface between the substrate layer and the resin layer.

[0050] <Separation process> In the present invention, the separation step is a process in which, after peeling off the substrate layer and the thermoplastic resin layer in the peeling step, the peeled substrate layer and the thermoplastic resin layer are selectively separated vertically in a solution by specific gravity separation. For example, the substrate layer, which is made of aluminum foil with a specific gravity of 2.7, will settle in a peeling solution with a specific gravity of 1.05 to 1.61, and the thermoplastic resin layer, such as polyethylene, will float in a peeling solution with a specific gravity of 1.05 to 1.61, allowing for selective separation.

[0051] In the separation process, the specific gravity of the release solution can be reduced by adding water, and its specific gravity can be increased by adding components of the release solution such as formic acid or ammonium formate. Furthermore, if the composition of the container packaging material is known in advance, an appropriate specific gravity of the release solution can be selected to separate the base layer and the thermoplastic resin layer, and the base layer and the thermoplastic resin layer can be separated using the specific gravity of the release solution without adding additional water or components of the release solution.

[0052] If the specific gravity of the thermoplastic resin layer is greater than that of the release solution, and both the substrate layer and the thermoplastic resin layer settle, it is possible to float only the thermoplastic resin layer by causing bubbles to adhere to or entangle with it through bubbling. In this case, since the substrate layer is rigid, has high strength against deformation, and is dense and thick, it will not float due to the effect of bubbles adhering to it through bubbling unless the thermoplastic resin layer adheres to or entangles with it in the solution. In the separation process, the peeling solution may be stirred or vibrated to promote separation after peeling. In this case, the adhesion between the substrate layer and the thermoplastic resin layer is loosened, and specific gravity separation is promoted.

[0053] In the separation process, if the specific gravity of the release solution falls below 1.05, the effect of specific gravity separation cannot be sufficiently obtained, and the thermoplastic resin layer cannot be floated. If the specific gravity of the release solution exceeds 1.61, the fluidity of the release solution deteriorates, making it difficult to separate the substrate layer from the resin layer. [Examples]

[0054] The separation and recovery methods of the examples and comparative examples according to the present invention were evaluated by the following methods, and will be described in detail below.

[0055] 1. Preparation of test specimens (container and packaging materials) [Test specimen 1] For the aluminum foil, 20 μm 1N30 material (manufactured by Toyo Aluminum Co., Ltd., hard foil) was used. Subsequently, a polyolefin-based white coating agent (manufactured by T&K TOKA: PPZ-C 96 white, solid content 34% by mass) was applied to the glossy side of the aluminum foil using a bar coater #8, and the weight after drying was 1.5 g / m². 2 The coating was applied in this manner and dried at 150°C for 1 minute. Next, a vinyl chloride vinyl acetate copolymer coating agent (Leader Corporation: LD#S837G Clear, solid content 21% by mass) was applied to the matte side of the aluminum foil using a bar coater #12, and the weight after drying was 3.0 g / m². 2 The container packaging material for test specimen 1 was prepared by applying the material in this manner and drying it at 150°C for 1 minute to form a thermoplastic resin layer. The layer structure of test specimen 1 is polyolefin (white) / aluminum foil / vinyl chloride vinyl acetate copolymer.

[0056] [Test specimen 2] A urethane adhesive (DICG Corporation: main component LX-500, solid content 60% by mass; hardener KW-75, solid content 75% by mass; 10 parts by mass, 1 part by mass, and 11 parts by mass of ethyl acetate, mixed until the color is uniform) was applied to the glossy side of the aluminum foil with a bar coater #14, and the weight after drying was 5.0 g / m². 2 The material was applied in the manner described above, and dried at 120°C for 1 minute to form a urethane resin adhesive layer. Next, a 30 μm thick polyethylene film (Toyobo Co., Ltd.: Rix L4100) was bonded to it using a small laminator at a nip temperature of 60°C and a speed of 5 m / min. Furthermore, a urethane resin adhesive layer was formed on the matte side of the aluminum foil in the same manner as on the glossy side, and a 30 μm thick polyethylene film (Toyobo Co., Ltd.: Rix L4100) was bonded to it. The container packaging material for test specimen 2 was then prepared by curing at 40°C for 3 days. The layer composition of test specimen 2 is polyethylene / urethane adhesive / aluminum foil / urethane adhesive / polyethylene.

[0057] [Test specimen 3] A urethane-based colored coating agent (DIC's Finart R793 White E1, diluted for 15 seconds in a Zaan Cup No. 3 with the dedicated solvent Finart Reducer No. 1) was applied to the corona-treated side of a 12μm thick polyethylene terephthalate film (Toyobo Co., Ltd.: E5100) using a bar coater #12. The weight after drying was 3.0g / m². 2 The surface was coated and dried at 50°C for 3 minutes. Subsequently, a urethane adhesive (DICG Corporation: main component LX-500, solid content 60% by mass; hardener KW-75, solid content 75% by mass; 10 parts by mass, 1 part by mass, and 11 parts by mass of the main component, hardener, and ethyl acetate, mixed until the color was uniform) was applied with a bar coater #14, resulting in a weight of 5.0 g / m² after drying. 2 The material was applied in this manner and dried at 80°C for 10 seconds to form a urethane resin adhesive layer. Next, a 30 μm thick polyethylene film (Toyobo Co., Ltd.: Rix L4100) was bonded to the material using a small laminator at a nip temperature of 60°C and a speed of 5 m / min, and then cured at 40°C for 3 days to produce the container packaging material for test specimen 3. The layer composition of test specimen 3 is polyethylene terephthalate / white urethane coloring / urethane adhesive / polyethylene.

[0058] [Test specimen 4] A urethane-based primer coating agent (DIC's Finart R Medium, diluted in Finart Reducer No. 1 with a dedicated solvent and Zahn Cup No. 3 for 15 seconds) was applied to the corona-treated side of a 12μm thick polyethylene terephthalate film (Toyobo Co., Ltd.: E5100) using a bar coater #6. The weight after drying was 1.0g / m². 2 The material was applied in this manner and dried at 50°C for 30 seconds. Furthermore, a urethane-based colored coating agent (DIC's Finart R793 White E1, diluted to 15 seconds in a Zaan Cup No. 3 with the dedicated solvent Finart Reducer No. 1) was applied with a Bar Coater #12, and the weight after drying was 3.0 g / m². 2The surface was coated and dried at 50°C for 3 minutes. Subsequently, a urethane adhesive (DICG Corporation: main component LX-500, solid content 60% by mass; hardener KW-75, solid content 75% by mass; 10 parts by mass, 1 part by mass, and 11 parts by mass of the main component, hardener, and ethyl acetate, mixed until the color was uniform) was applied with a bar coater #14, resulting in a weight of 5.0 g / m² after drying. 2 The material was applied in this manner and dried at 80°C for 10 seconds to form a urethane resin adhesive layer. Next, a 30 μm thick unoriented polypropylene film (Toyobo Co., Ltd.: Pyrene Film CT P1128) was bonded to it using a small laminator at a nip temperature of 60°C and a speed of 5 m / min, and cured at 40°C for 3 days to produce the container packaging material for test specimen 4. The layer composition of test specimen 4 is polyethylene terephthalate / primer / white urethane coloring / urethane adhesive / unstretched polypropylene.

[0059] [Test specimen 5] The paper is 55 g / m² 2 Single-sided coated paper (manufactured by Daio Paper Corporation, Ryuoh Coated Paper) was used. Next, polyethylene coating (manufactured by Sumitomo Chemical Co., Ltd., Sumikasen L705) was applied to the rough side of the paper to a thickness of 20 μm using a polyethylene melt extruder to form a thermoplastic resin layer, and the container packaging material for test specimen 5 was prepared. In other words, the layer structure of test specimen 5 is paper / polyethylene.

[0060] Table 1 shows the layer structure of the container packaging materials for test specimens 1 to 5. [Table 1]

[0061] 2. Preparation of the stripping solution [Peeling solution (a)] In a 1000 mL glass bottle (105 mm in diameter, 160 mm in height), 144.9 g of nitric acid (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., reagent grade, 69% by mass), 300 g of citric acid (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., Wako special grade), and 555.1 g of purified water (manufactured by AS ONE Corporation, ASSWS-20) were added and stirred at 40°C for 30 minutes to prepare a stripping solution (a) with a specific gravity of 1.24.

[0062] [Removal solution (a)-2] In a 1000mL glass bottle (105mm in diameter, 160mm in height), 39.5g of formic acid (manufactured by Asahi Chemical Industries, Ltd., reagent grade, 76% by mass), 1g of citric acid (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., Wako special grade), and 959.5g of purified water (manufactured by AS ONE, ASSWS-20) were added and stirred at 40°C for 30 minutes to prepare stripping solution (a)-2 with a specific gravity of 1.01.

[0063] [Peeling solution (b)] In a 1000 mL glass bottle (105 mm in diameter, 160 mm in height), 72.5 g of nitric acid (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., reagent grade, 69% by mass), 50 g of ammonium formate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., Wako special grade), and 878 g of purified water (manufactured by AS ONE, ASSWS-20) were added and stirred at 40°C for 30 minutes to prepare a stripping solution (b) with a specific gravity of 1.03.

[0064] [Peeling solution (c)] In a 1000 mL glass bottle (105 mm in diameter, 160 mm in height), 450 g of formic acid (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., reagent grade), 200 g of butyl acetate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., reagent grade), 250 g of purified water (manufactured by AS ONE Corporation, ASSWS-20), and 100 g of methyl ethyl ketone (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., reagent grade) were added and stirred at room temperature for 10 minutes to prepare a stripping solution (c) with a specific gravity of 1.06.

[0065] [Peeling solution (d)] In a 1000 mL glass bottle (105 mm in diameter, 160 mm in height), 281.3 g of sulfuric acid (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., reagent grade, 64% by mass), 500 g of sodium formate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., Wako special grade), and 471.9 g of purified water (manufactured by AS ONE Corporation, ASSWS-20) were added, and the mixture was stirred at 40°C for 30 minutes to prepare a stripping solution (d) with a specific gravity of 1.61.

[0066] [Removal solution (d)-2] In a 1000 mL glass bottle (105 mm in diameter, 160 mm in height), 109.4 g of sulfuric acid (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., reagent grade, 64% by mass), 100.0 g of sodium formate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., Wako special grade), and 790.6 g of purified water (manufactured by AS ONE, ASSWS-20) were added and stirred at 40°C for 30 minutes to prepare stripping solution (d)-2 with a specific gravity of 1.15.

[0067] [Removal solution (d)-3] In a 1000 mL glass bottle (105 mm in diameter, 160 mm in height), 343.8 g of sulfuric acid (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., reagent grade, 64% by mass), 600 g of sodium formate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., Wako special grade), and 365.6 g of purified water (manufactured by AS ONE, ASSWS-20) were added, and the mixture was stirred at 40°C for 30 minutes to prepare stripping solution (d)-3 with a specific gravity of 1.61.

[0068] [Peeling solution (e)] 100 g of formic acid (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., reagent grade) and 900 g of purified water (manufactured by AS ONE, ASSWS-20) were added to a 1000 mL glass bottle (105 mm in diameter and 160 mm in height), and the mixture was stirred at 40°C for 30 minutes to prepare a stripping solution (e) with a specific gravity of 1.02.

[0069] [Peeling solution (f)] In a 1000mL glass bottle (105mm in diameter, 160mm in height), 100g of sodium hydroxide (Fujifilm Wako Pure Chemical Industries, Ltd., granular, reagent grade) and 900g of purified water (AS ONE Corporation, ASSWS-20) were added and stirred at 40°C for 30 minutes to prepare a stripping solution (f) with a specific gravity of 1.02.

[0070] [Removal solution (f)-2] In a 1000 mL glass bottle (105 mm in diameter, 160 mm in height), 10 g of sodium hydroxide (Fujifilm Wako Pure Chemical Industries, Ltd., granular, reagent grade) and 990 g of purified water (AS ONE Corporation, ASSWS-20) were added and stirred at 40°C for 30 minutes to prepare stripping solution (f)-2 with a specific gravity of 1.00.

[0071] 3. Crushing process, peeling process <Sampling of crushed material> When a large quantity of crushed material was obtained, sampling of the crushed specimen was performed according to the incremental reduction method of JIS Z 8816:2001, unless otherwise specified. The incremental reduction method is: The sample was spread out on a flat surface (A4 size) in a rectangular shape with a uniform thickness. The spread-out sample was divided into 10 equal parts. One sample was randomly taken from each of the divided sections, and these were collected to form the test sample. To avoid any subjectivity, samples were taken from the topmost sample at the center point of each section.

[0072] [Example 1] Using a cutting machine (WOHLEBERG, 115MCS-3TY), test specimen 1 was cut into 20mm x 20mm squares to obtain 10 crushed test specimens. Next, the release solution (a) was heated to 70°C in a water bath, and the 10 crushed test specimens were immersed in it and left to stand for 1 hour. After that, the separation and recovery method of Example 1 was performed by rotating a stirring bar (Flon Chemical, NR3032-007, 50mm) in the release solution (a) at 20 rpm x 1 minute, and then letting it stand for 1 minute.

[0073] [Example 2] The separation and recovery method of Example 2 was performed under the same conditions as in Example 1, except that 10 pieces of crushed specimen material were used, which were obtained by cutting specimen 1 into 15 mm x 75 mm rectangles using a cutting machine (WOHLEBERG, 115MCS-3TY).

[0074] [Example 3] The separation and recovery method of Example 3 was performed under the same conditions as in Example 1, except that 10 pieces of crushed test specimen material were used, which were obtained by cutting test specimen 1 into 7 mm x 7 mm squares using a cutting machine (WOHLEBERG, 115MCS-3TY).

[0075] [Example 4] The separation and recovery method of Example 4 was performed under the same conditions as in Example 1, except that 10 pieces of crushed test specimen material were used, which were obtained by cutting test specimen 1 into 45 mm x 45 mm squares using a cutting machine (WOHLEBERG, 115MCS-3TY).

[0076] [Example 5] Using a cutting machine (WOHLEBERG, 115MCS-3TY), test specimen 1 was cut into 20mm x 20mm squares to obtain 10 crushed test specimens. Next, the peeling solution (a)-2 was heated to 70°C in a water bath, and the 10 crushed test specimens were immersed in it and left to stand for 1 hour. After that, a silicone tube with an outer diameter of 9mm and a thickness of 2mm was placed at the bottom of a 1000mL glass bottle, along the inner wall of the glass bottle, to form an annular shape with a diameter of approximately 100mm. Ten holes with a diameter of 2mm were drilled at equal intervals in the annular portion of the silicone tube, and a wire with a diameter of 1mm was inserted into the silicone tube to maintain the shape. Then, the separation and recovery method of Example 5 was performed by supplying air into the silicone tube at a flow rate of 25ml / min for 30 seconds (bubbling).

[0077] [Example 6] Using a cutting machine (WOHLEBERG, 115MCS-3TY), test specimen 1 was cut into 20mm x 20mm squares to obtain 10 crushed test specimens. Next, the release solution (d) was heated to 70°C in a water bath, and the 10 crushed test specimens were immersed in it and left to stand for 1 hour. After that, the separation and recovery method of Example 6 was performed by rotating a stirring bar (Flon Chemical, NR3032-007, 50mm) in the release solution (d) at 20 rpm x 1 minute, and then letting it stand for 1 minute.

[0078] [Example 7] Using a cutting machine (WOHLEBERG, 115MCS-3TY), test specimen 1 was cut into 25 mm x 50 mm rectangles, yielding 10 crushed test specimens. Next, the release solution (a) was heated to 70°C in a water bath, and the 10 crushed test specimens were immersed in it and left to stand for 1 hour. After that, the separation and recovery method of Example 7 was performed by rotating a stirring bar (Flon Chemical, NR3032-007, 50 mm) in the release solution (a) at 20 rpm x 1 minute, followed by standing for 1 minute.

[0079] [Example 8] Using a sheet pelletizer (Sanriki Seisakusho Co., Ltd., SGP-800), test specimen 1 was cut into 20 mm x 20 mm squares, yielding 10 crushed test specimens. The separation and recovery method of Example 7 was performed by rotating a stirring bar (Flon Chemical Co., Ltd., NR3032-007, 50 mm) at 20 rpm for 1 minute in the stripping solution (a), followed by standing for 1 minute. Next, the stripping solution (a) was heated to 70°C in a water bath, and the 10 crushed test specimens were immersed and left to stand for 1 hour. After that, the separation and recovery method of Example 8 was performed by rotating a stirring bar (Flon Chemical Co., Ltd., NR3032-007, 50 mm) at 20 rpm for 1 minute in the stripping solution (a), followed by standing for 1 minute.

[0080] [Example 9] Using a large shredder (Nakabayashi Co., Ltd., NIS type), test specimen 1 was cut into 15 mm x 30 mm rectangles, yielding 10 shredded test specimens. Next, the release solution (a) was heated to 70°C in a water bath, and the 10 shredded test specimens were immersed in it and left to stand for 1 hour. After that, the separation and recovery method of Example 9 was performed by rotating a stirring bar (Flon Chemical Co., Ltd., NR3032-007, 50 mm) in the release solution (a) at 20 rpm x 1 minute, and then letting it stand for 1 minute.

[0081] [Example 10] Using a cutting machine (WOHLEBERG, 115MCS-3TY), test specimen 1 was cut into 20mm x 20mm squares to obtain 10 crushed test specimens. Next, the release solution (b) was heated to 70°C in a water bath, and the 10 crushed test specimens were immersed in it and left to stand for 1 hour. After that, the separation and recovery method of Example 10 was performed by rotating a stirring bar (Flon Chemical, NR3032-007, 50mm) in the release solution (b) at 20 rpm x 1 minute, and then letting it stand for 1 minute.

[0082] [Example 11] Using a cutting machine (WOHLEBERG, 115MCS-3TY), test specimen 1 was cut into 20mm x 20mm squares to obtain 10 crushed test specimens. Next, the release solution (c) was heated to 70°C in a water bath, and the 10 crushed test specimens were immersed in it and left to stand for 1 hour. After that, the separation and recovery method of Example 11 was performed by rotating a stirring bar (Flon Chemical, NR3032-007, 50mm) in the release solution (c) at 20 rpm for 1 minute, and then letting it stand for 1 minute.

[0083] [Example 12] Using a cutting machine (WOHLEBERG, 115MCS-3TY), test specimen 1 was cut into 20mm x 20mm squares to obtain 10 crushed test specimens. Next, the release solution (d)-2 was heated to 70°C in a water bath, and the 10 crushed test specimens were immersed in it and left to stand for 1 hour. After that, the separation and recovery method of Example 12 was performed by rotating a stirring bar (Flon Chemical, NR3032-007, 50mm) in the release solution (d)-2 at 20 rpm for 1 minute, and then letting it stand for 1 minute.

[0084] [Example 13] Using a cutting machine (WOHLEBERG, 115MCS-3TY), test specimen 1 was cut into 20mm x 20mm squares to obtain 10 crushed test specimens. Next, the release solution (e) was heated to 70°C in a water bath, and the 10 crushed test specimens were immersed in it and left to stand for 1 hour. After that, a silicone tube with an outer diameter of 9mm and a thickness of 2mm was placed at the bottom of a 1000mL glass bottle, along the inner wall of the glass bottle, to form an annular shape with a diameter of approximately 100mm. Ten holes with a diameter of 2mm were drilled at equal intervals in the annular portion of the silicone tube, and a wire with a diameter of 1mm was inserted into the silicone tube to maintain the shape. Then, the separation and recovery method of Example 13 was performed by supplying air into the silicone tube at a flow rate of 25ml / min for 30 seconds (bubbling).

[0085] [Example 14] Using a cutting machine (WOHLEBERG, 115MCS-3TY), test specimen 2 was cut into 20mm x 20mm squares to obtain 10 crushed test specimens. Next, the release solution (c) was heated to 70°C in a water bath, and the 10 crushed test specimens were immersed in it and left to stand for 1 hour. After that, the separation and recovery method of Example 14 was performed by rotating a stirring bar (Flon Chemical, NR3032-007, 50mm) in the release solution (c) at 20 rpm for 1 minute, and then letting it stand for 1 minute.

[0086] [Example 15] Using a cutting machine (WOHLEBERG, 115MCS-3TY), test specimen 3 was cut into 20mm x 20mm squares to obtain 10 crushed test specimens. Next, the stripping solution (f) was heated to 70°C in a water bath, and the 10 crushed test specimens were immersed in it and left to stand for 1 hour. After that, the separation and recovery method of Example 15 was performed by rotating a stirring bar (Flon Chemical, NR3032-007, 50mm) in the stripping solution (c) at 20 rpm for 1 minute, and then letting it stand for 1 minute.

[0087] [Example 16] Test specimen 4 was crushed using a single-shaft shredder (Horai Co., Ltd., B03A-210LFE, 20mm x 20mm mesh) to obtain 10 fragments of the test specimen. Next, the stripping solution (f) was heated to 70°C in a water bath, and the 10 fragments of the test specimen were immersed in it and left to stand for 1 hour. Subsequently, the separation and recovery method of Example 16 was performed by rotating a stirring bar (Flon Chemical Co., Ltd., NR3032-007, 50 mm) in the stripping solution (f) at 20 rpm for 1 minute, followed by standing for 1 minute.

[0088] [Example 17] Using a cutting machine (WOHLEBERG, 115MCS-3TY), test specimen 5 was cut into 20mm x 20mm squares, yielding 10 crushed test specimens. Next, the release solution (f) was heated to 70°C in a water bath, and the 10 crushed test specimens were immersed in it and left to stand for 1 hour. After that, the separation and recovery method of Example 16 was performed by rotating a stirring bar (Flon Chemical, NR3032-007, 50mm) in the release solution (f) at 20 rpm for 1 minute, followed by standing for 1 minute.

[0089] [Comparative Example 1] The separation and recovery method for Comparative Example 1 was performed under the same conditions as for Example 1, except that 10 crushed specimens were used, which were obtained by cutting specimen 1 into 6 mm x 6 mm squares using a cutting machine (WOHLEBERG, 115MCS-3TY).

[0090] [Comparative Example 2] The separation and recovery method for Comparative Example 2 was performed under the same conditions as in Example 1, except that 10 pieces of crushed specimen material were used, obtained by cutting specimen 1 into 7 mm x 42 mm rectangles using a cutting machine (WOHLEBERG, 115MCS-3TY).

[0091] [Comparative Example 3] The separation and recovery method for Comparative Example 3 was performed under the same conditions as in Example 1, except that 10 crushed specimens were used, obtained by cutting specimen 1 into 47 mm x 47 mm squares using a cutting machine (WOHLEBERG, 115MCS-3TY).

[0092] [Comparative Example 4] Using a cutting machine (WOHLEBERG, 115MCS-3TY), test specimen 1 was cut into 20 mm x 20 mm squares to obtain 10 crushed test specimens. Next, the 10 crushed test specimens were immersed in the release solution (f)-2, which was heated to 70°C in a water bath, and left to stand for 1 hour. After that, the separation and recovery method of Comparative Example 4 was performed by rotating a stirring bar (Flon Chemical, NR3032-007, 50 mm) in the release solution (f)-2 at 20 rpm for 1 minute, and then letting it stand for 1 minute.

[0093] [Comparative Example 5] Using a cutting machine (WOHLEBERG, 115MCS-3TY), test specimen 1 was cut into 20 mm x 20 mm squares, yielding 10 crushed test specimens. Next, the stripping solution (d)-3 was heated to 70°C in a water bath, and the 10 crushed test specimens were immersed in it and left to stand for 1 hour. After that, the separation and recovery method of Comparative Example 4 was performed by rotating a stirring bar (Flon Chemical, NR3032-007, 50 mm) in the stripping solution (d)-3 at 20 rpm for 1 minute, followed by standing for 1 minute.

[0094] 4. Measurement of the shape of the crushed material (1) Image capture Ten crushed test specimens were photographed together with a JIS Class 1 steel ruler using a wide-angle camera (Apple smartphone (iPhone SE)) at 20mm f1.8 with an image size of 3024 x 4032 pixels. To ensure sharpness, the camera was focused from a height of 25mm to 30mm before being mounted on a smartphone tripod.

[0095] (2) Measurement of width, area, and aspect ratio of crushed test specimens by image analysis Image analysis was performed using WinRoof2023 (Mitani Corporation, Version: 6.7.1) following the procedure below. • The image's scale markings were read during calibration, and the image was synchronized with its actual size. The captured image was loaded and converted to a monochrome image. • Automatic binarization was performed using discriminant analysis. To remove noise, areas detected with a threshold of 10 or less were deleted in bulk using binary processing deletion mode. Based on the shape characteristics, the Ferret's short axis II, Ferret's long axis II, and area of ​​the crushed specimens were measured. In this invention, the width, area, and aspect ratio of the crushed test specimen were defined as follows. • Width: Ferret's minor diameter II as measured with WinRoof2023 • Area: Area measured using WinRoof2023 • Aspect ratio: The ratio of the short axis II to the long axis II of the ferret, as measured with WinRoof2023. Furthermore, Ferret diameter II refers to the major and minor axes of the Ferret ellipse, which are automatically adjusted so that the tilt of the object does not affect the measurement. In addition, in the case of a standard-shaped crushed material, as shown in one example, it was confirmed that the cutting dimensions (set value) matched the width, area, and aspect ratio obtained from image analysis, so the set value was used as the cutting dimensions of the test specimen. Figure 1 shows an example of the crushed test specimen from Example 1.

[0096] Furthermore, as in Example 16, the shape of the crushed material (width, area, aspect ratio) is not necessarily rectangular; circular or irregular shapes may be obtained. Table 2 shows the image analysis results. Figure 2 shows an example of the crushed test specimen from Example 16. [Table 2] * "Range" ... Test specimen crushed material width 7 mm to 45 mm, area 49 mm 2 That's all. 2025mm 2 Below, aspect ratios are 1:1 to 1:5

[0097] As shown in Table 2, the ferret diameters of the irregularly shaped crushed specimens in Example 16 ranged from 9 mm to 30 mm, the ferret diameters from 5 mm to 12 mm, and the area from 38 to 154 mm². 2The aspect ratio was between 1:1.4 and 1:3.7. Of the 10 items, 2 were "width between 7mm and 45mm, area of ​​49mm". 2 More than 2025mm 2 Although it falls outside the range of "below," the median values ​​are 14 mm in major diameter, 8 mm in minor diameter, and 58 mm in area. 2 The aspect ratio is 1:1.9, and the width is 7mm or more and 45mm or less, with an area of ​​49mm. 2 More than 2025mm 2 The following aspects fell within the range of "1:1 to 1:5". Thus, in the case of the irregularly shaped crushed specimens of Example 16, it was found that if at least 50% by mass of the total crushed material falls within the above-mentioned specific range, separation can be performed without problems in the evaluation of the separation and recovery method described later.

[0098] 5. Evaluation of the separation and recovery method The separation and recovery methods for Examples 1 to 16 and Comparative Examples 1 to 5 were evaluated according to the following criteria. Specifically, for Test Specimens 1 and 2, in which resin layers are laminated on both sides of the substrate layer, In the separation process, out of 10 crushed materials, 20 thermoplastic resin layers floated to the surface and 10 base material layers settled, separating them into upper and lower layers, which are designated as "A". In the separation process, out of 10 crushed materials, 14 to 18 thermoplastic resin layers floated to the surface, and 7 to 9 base material layers settled, separating them into upper and lower layers, which are designated as "B". In the separation process, out of 10 crushed materials, 10 to 14 thermoplastic resin layers floated to the surface, and 5 to 7 base material layers settled, separating them into upper and lower layers, which are designated as "C". In the separation process, if fewer than 10 thermoplastic resin layers float and fewer than 5 base material layers sink, or if the layers float or sink while entangled with either one of the layers, it is classified as "F" (unable to separate). It was evaluated as such.

[0099] Furthermore, for test specimens 3, 4, and 5, in which a resin layer is laminated on one side of the base material layer, In the separation process, out of 10 crushed materials, 10 thermoplastic resin layers floated to the surface and 10 base material layers settled, separating them into upper and lower layers, which are designated as "A". In the separation process, out of 10 crushed materials, 7 to 9 thermoplastic resin layers floated to the surface, and 7 to 9 base material layers settled, separating them into upper and lower layers, which are designated as "B". In the separation process, out of 10 crushed materials, 5 to 7 thermoplastic resin layers floated to the surface, and 5 to 7 base material layers settled, separating them into upper and lower layers, which are designated as "C". In the separation process, if fewer than 5 thermoplastic resin layers float and fewer than 5 base material layers sink, or if the layers float or sink while entangled with either one of the layers, it is classified as "F" (unable to separate). It was evaluated as such.

[0100] Table 3 shows the conditions for crushed material, immersion conditions for peeling solutions, and evaluation results for the separation and recovery methods in Examples 1-16 and Comparative Examples 1-5. Where there is a distribution in the width of the crushed material, the median value is shown as an example. [Table 3]

[0101] <Consideration> As shown in Table 1, the separation and recovery methods of Comparative Examples 1 to 5 all received an "F" rating, while the separation and recovery methods of Examples 1 to 17 received "A," "B," or "C" ratings. This indicates that the separation and recovery methods of Examples 1 to 17 can efficiently separate the container and packaging material into the resin layer and the base layer while suppressing entanglement between the thermoplastic resin layer, such as polyolefin, and the base material layer, such as aluminum foil, in the peeling solution.

[0102] More specifically, in Example 3 and Comparative Example 1, it was observed that when the width of the crushed material is less than 7 mm, air (bubbles) becomes entangled or trapped in the sediment (crushed material) and floats to the surface, making separation and recovery difficult. In Example 4 and Comparative Example 3, it was observed that when the width of the crushed material is greater than 45 mm, the peeled resin layer reattaches to the substrate layer, making separation and recovery difficult.

[0103] Furthermore, in Example 4 and Comparative Example 1, the area of ​​the crushed material was 49 mm². 2When the area becomes smaller than 2025 mm², the sediment (crushed material) has difficulty settling or floating, and evaluations such as in Example 4 indicate that the crushed material area is 2025 mm². 2 When the size exceeds a certain limit, it was observed that the resin layer after peeling becomes too large and entangles with the substrate layer, making separation and recovery difficult.

[0104] Furthermore, in Example 2 and Comparative Example 2, it was observed that when the aspect ratio of the crushed material exceeds 1:5, air (bubbles) becomes entangled or trapped in the elongated crushed material, causing it to float and making separation and recovery difficult. Also, in Example 6 and Comparative Example 5, it was observed that when the specific gravity of the peeling solution exceeds 1.61, the fluidity decreases, making separation and recovery difficult. Finally, in the evaluation of Comparative Example 4, it was observed that when the specific gravity of the peeling solution falls below 1.05, the resin layer settles together with the substrate layer, making separation and recovery difficult.

[0105] Furthermore, it was found that the crushing method for container packaging materials in the present invention is not limited to cutting, and other crushing methods such as sheet pelletizers, shredders, and uniaxial crushing methods, as shown in Examples 8, 9, and 16, can also be used. In addition, it was found that the layer structure of container packaging materials in the present invention is not limited as long as at least the thermoplastic resin layer is in close contact with the base material layer (see Examples 14, 15, and 16), and that resin layers such as PET resin or paper can be used as the base material (layer) (see Examples 15, 16, and 17).

[0106] As shown in Example 16, in the separation and recovery method of the present invention, the shape (width, area, aspect ratio) of the crushed material obtained by crushing the container packaging material does not necessarily have to be rectangular. It may be irregular in shape, or even if there is a variation in width, as long as the width is between 7 mm and 45 mm and the area is 49 mm 2 More than 2025mm 2 Furthermore, it was found that the resin layer and the base material layer can be separated and recovered from the container packaging material if the aspect ratio is within the range of 1:1 to 1:5.

[0107] As described above, according to the separation and recovery methods of Examples 1 to 17, the container packaging material, which includes a base layer and a thermoplastic resin layer bonded to the base layer, has a width of 7 mm to 45 mm and an area of ​​49 mm².2 More than 2025mm 2 It was found that by crushing the material so that the aspect ratio is 1:1 to 1:5, and then immersing the crushed material in a release solution with a specific gravity of 1.05 to 1.61 to separate it into a base layer and a resin layer, the container packaging material can be efficiently separated into a resin layer and a base layer while suppressing entanglement between the thermoplastic resin layer and the base layer in the release solution. [Explanation of Symbols]

[0108] 1. Crushed specimens of a standard (rectangular) shape. 2. Irregularly shaped crushed test specimens 3...scale

Claims

1. A method for separating and recovering a container packaging material comprising a base layer and a thermoplastic resin layer bonded to the base layer by crushing the material and immersing it in a release solution, wherein the base layer and the resin layer are separated. By crushing the container packaging material, the width is between 7 mm and 45 mm, and the area is 49 mm. ２ 2025mm or more ２ The following describes a crushing process to obtain crushed material with an aspect ratio of 1:1 to 1:5, A peeling step in which the crushed material is immersed in a peeling solution having a specific gravity of 1.05 or more and 1.61 or less, The system includes a separation step of peeling and separating the base material layer and the resin layer, and The substrate layer is formed from at least one selected from the group consisting of aluminum foil and polyethylene terephthalate (PET). The thermoplastic resin layer is formed from at least one selected from the group consisting of polyethylene, polypropylene, and vinyl chloride-vinyl acetate copolymer, and The aforementioned peeling solution <Removal solution (a)> A stripping solution (a) containing a first acid consisting of at least one of nitric acid and formic acid, one or more second acids selected from the group consisting of polycarboxylic acids and hydroxy acids, and water. <Removal solution (b)> A stripping solution (b) containing an ammonium salt consisting of at least one of ammonium formate and ammonium acetate, one or more acids selected from the group consisting of nitric acid, sulfuric acid, phosphoric acid, formic acid and acetic acid, and water. <Removal solution (c)> A stripping solution (c) comprising formic acid, a carboxylic acid ester consisting of a formic acid ester having 9 or fewer carbon atoms and / or an acetate ester having 9 or fewer carbon atoms, and water. <Removal solution (d)> A stripping solution (d) containing a metal carboxylic acid salt, an acid, and a polar solvent. <Removal solution (e)> A stripping solution (e) which is an aqueous solution of formic acid, or <Removal solution (f)> The stripping solution (f) is an aqueous solution of sodium hydroxide. A method for separating and recovering container and packaging materials, characterized by the above.

2. The separation and recovery method according to claim 1, wherein the crushing step comprises one or more methods selected from the group consisting of a cutting method, a sheet pelletizer method, a shredder method, and a single-shaft crushing method.

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