Method for separating aluminum foil laminate

Abstract

To provide a method for efficiently separating an aluminum foil laminate into an aluminum foil and a resin layer in a short time.SOLUTION: A method for separating an aluminum foil and a resin layer from an aluminum foil laminate having the aluminum foil and the resin layer has in order: a recess forming step of forming recesses in the aluminum foil laminate; a crushing step of crushing the aluminum foil laminate to obtain crushed pieces; and an immersion step of immersing the crushed pieces in a release agent solution, wherein the release agent solution has either a specific composition (release agent solution A) or a specific composition (release agent solution B).SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a method for separately recovering aluminum foil and resin from an aluminum foil laminate in which an aluminum foil and a resin are laminated.

Background Art

[0002] Conventionally, in applications where barrier properties are required to protect the contents from the external environment such as oxygen, water vapor, and ultraviolet rays, as packaging materials for food and pharmaceuticals, laminates in which resin layers are laminated on both sides of an aluminum foil have been widely used. Since a large amount of electric power is required for refining aluminum, it is known as a material with a very high recycling rate. On the other hand, in a laminate in which a resin layer is laminated on an aluminum foil, it has been difficult to separate the aluminum foil and the resin layer, so there has been a problem that recycling has not advanced. In contrast, for example, in Patent Document 1 (Japanese Unexamined Patent Application Publication No. 2014-19003), a composite material in which two or more thin film materials are laminated via an adhesive is crushed, brought into contact with a release agent solution to be peeled off, and then a plurality of specific gravity separation liquids having different specific gravities are used to separate the thin film materials.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the technique described in Patent Document 1, an alkaline release agent solution is used to swell and separate the adhesive that bonds the resin layer and the aluminum foil, and immersion for 4 to 30 hours is required. On the other hand, if aluminum is immersed in the alkaline release agent solution for a long time, the aluminum may dissolve and it may not be possible to sufficiently recover it as aluminum foil. That is, if the immersion time in the release agent solution is short, the aluminum foil cannot be separated, and if it is too long, the aluminum foil will dissolve. In any case, it was difficult to separate the aluminum foil from the aluminum foil laminate. Further, when immersing the crushed aluminum foil laminate in the release agent solution, if the crushed pieces are made smaller to facilitate separation, the influence of the viscous resistance received from the release agent solution becomes larger, and the sedimentation of the aluminum foil pieces separated from the crushed pieces and the floating of the resin pieces are difficult to proceed, so it was difficult to shorten the time required for separation. Therefore, an object of the present invention is to provide a method capable of efficiently separating the aluminum foil and the resin layer from the aluminum foil laminate in a short time while suppressing the elution of the aluminum foil.

Means for Solving the Problems

[0005] As a result of intensive research to solve such problems, it was found that the time required for separation can be shortened by providing recesses in the crushed pieces in advance and immersing them in a predetermined release agent solution. That is, the method for separating an aluminum foil laminate of the present invention is a separation method for separating an aluminum foil and a resin layer from an aluminum foil laminate having an aluminum foil and a resin layer, and includes a recess-providing step of providing recesses in the aluminum foil laminate, a crushing step of crushing the aluminum foil laminate to obtain crushed pieces, and an immersion step of immersing the crushed pieces in a release agent solution in this order.

[0006] Further, the release agent solution is (Release Agent Solution A) ammonium formate and ammonium acetate, with at least one ammonium salt consisting of 1.2% by mass or more and 75% by mass or less, one or more first acids selected from the group consisting of nitric acid, sulfuric acid, phosphoric acid, formic acid, and acetic acid, 2% by mass or more and 30% by mass or less, and water 23% by mass or more and 96.8% by mass or less. The total of the ammonium salt, the first acid, and the water is 100% by mass or less in the release agent solution A, and the content ratio obtained by dividing the content (% by mass) of the ammonium salt by the content (% by mass) of the first acid is 0.1 or more and 37.5 or less. (Release Agent Solution B) A second acid consisting of at least one of nitric acid and formic acid, 2% by mass or more and 35% by mass or less, one or more third acids selected from the group consisting of polycarboxylic acids, hydroxy acids, polycarboxylate salts, and hydroxycarboxylate salts, 0.1% by mass or more and 35% by mass or less, and water 40% by mass or more and 97.7% by mass or less. The total of the second acid, the third acid, and the water is 100% by mass or less in the release agent solution B, and the content ratio obtained by dividing the content (% by mass) of the second acid by the content (% by mass) of the third acid is 0.057 or more and 30 or less. It is either of these.

[0007] In the above recess-forming step, it is preferable to send the aluminum foil laminate to the crushing step using at least one pair of rolls, and form recesses in the aluminum foil laminate simultaneously with the feeding by the convex portions provided on the surface of at least one of the rolls.

[0008] The above recess-forming step is preferably a step of forming recesses in the aluminum foil laminate with a needle having a sharp tip of the convex portion.

[0009] The recess-forming step is preferably a step of forming recesses by at least one of through-holes and cuts that penetrate the aluminum foil laminate.

[0010] The crushing step is preferably a step of crushing the aluminum foil laminate into a rectangle with a side length of 1 mm or more and 50 mm or less.

[0011] It is preferable that the release agent solution A contains 10% by mass or less of one or more acids selected from the group consisting of polycarboxylic acids, hydroxy acids, polycarboxylate salts, and hydroxycarboxylate salts as the balance.

[0012] It is preferable that the release agent solution A contains 50% by mass or less of one or more organic solvents selected from the group consisting of ketones, ethers, alkylbenzenes, dioxolanes, cycloalkanes, and carboxylic acid esters.

[0013] It is preferable that the third acid in the release agent solution B is one or more selected from citric acid, tartaric acid, lactic acid, malic acid, maleic acid, phthalic anhydride, sodium citrate, and diammonium hydrogen citrate.

Advantages of the Invention

[0014] According to the present invention, by using the above-described release agent solution, the aluminum foil and the resin layer can be separated, and furthermore, since the release agent solution penetrates from the recess provided in the recessed portion forming step and easily spreads over the interface between the aluminum foil and the resin layer, the aluminum foil and the resin layer can be efficiently separated in a short time.

Brief Description of the Drawings

[0015]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Embodiments for Carrying Out the Invention

[0016] Hereinafter, embodiments of the present invention will be described in detail. The following description of the preferred embodiments is merely illustrative in nature and is not intended to limit the present invention, its applications, or its uses. (Method for Separating Aluminum Foil Laminates)

[0017] The method for separating an aluminum foil laminate of the present invention is a separation method for separating the aluminum foil and the resin layer from an aluminum foil laminate having an aluminum foil and a resin layer, and includes a recess-providing step of providing a recess in the aluminum foil laminate, a crushing step of crushing the aluminum foil laminate to obtain crushed pieces, and an immersion step of immersing the crushed pieces in a release agent solution. Further, the release agent solution contains (Release Agent Solution A) an ammonium salt composed of at least one of ammonium formate and ammonium acetate in an amount of 1.2% by mass or more and 75% by mass or less, one or more first acids selected from the group consisting of nitric acid, sulfuric acid, phosphoric acid, formic acid, and acetic acid in an amount of 2% by mass or more and 30% by mass or less, and water in an amount of 23% by mass or more and 96.8% by mass or less, and the total of the ammonium salt, the first acid, and the water is 100% by mass or less in the release agent solution A, and the content ratio obtained by dividing the content (% by mass) of the ammonium salt by the content (% by mass) of the first acid is 0.1 or more and 37.5 or less. (Release Agent Solution B) It contains a second acid consisting of at least one of nitric acid and formic acid in an amount of 2% by mass or more and 35% by mass or less, one or more third acids selected from the group consisting of polycarboxylic acids, hydroxy acids, polycarboxylate salts, and hydroxycarboxylate salts in an amount of 0.1% by mass or more and 35% by mass or less, and water in an amount of 40% by mass or more and 97.7% by mass or less. The total of the second acid, the third acid, and the water is 100% by mass or less in the release agent solution B, and the content ratio obtained by dividing the content (% by mass) of the second acid by the content (% by mass) of the third acid is 0.057 or more and 30 or less. is any of the following.

[0018] In the recess-forming step, it is preferable to send out the aluminum foil laminate to the crushing step using at least one pair of rolls, and form a recess in the aluminum foil laminate simultaneously with the feeding by the convex portion provided on at least one surface of the roll.

[0019] The recess-forming step is preferably a step of forming a recess in the aluminum foil laminate with a needle having a sharp tip of the convex portion.

[0020] The recess-forming step is preferably a step of forming a recess by at least one of a through hole and a cut that penetrates the aluminum foil laminate.

[0021] The crushing step is preferably a step of crushing the aluminum foil laminate into a rectangle with a side length of 1 mm or more and 50 mm or less.

[0022] It is preferable that the release agent solution A contains, as the balance, one or more acids selected from the group consisting of polycarboxylic acids, hydroxy acids, polycarboxylate salts, and hydroxycarboxylate salts in an amount of 10% by mass or less.

[0023] It is preferable that the release agent solution A contains one or more organic solvents selected from the group consisting of ketones, ethers, alkylbenzenes, dioxolanes, cycloalkanes, and carboxylic acid esters in an amount of 50% by mass or less.

[0024] It is preferable that the third acid in the release agent solution B is one or more selected from citric acid, tartaric acid, lactic acid, malic acid, maleic acid, phthalic anhydride, sodium citrate, and diammonium hydrogen citrate.

[0025] <Aluminum foil laminate> In the present invention, the aluminum foil laminate only needs to include at least an aluminum foil and a resin layer. The aluminum foil laminate may be not only one in which a single resin layer and a single aluminum foil are laminated, but also one in which aluminum foils are provided on both sides of a sheet-like resin layer. Further, the aluminum foil laminate may include any layer other than the aluminum foil and the resin layer. For example, such an arbitrary layer includes those provided with arbitrary layers used in general packaging materials, such as adhesives, paper, non-woven fabrics, anchor coats, printing layers, OP varnish layers, adhesives, anti-adhesion layers made of fine particles, and filling particles. Such an aluminum foil laminate is not limited to a sheet-like one, and may be a structure such as a bag, a tube, or a container.

[0026] <Aluminum foil> In the present invention, the aluminum foil refers to all aluminum foils generally used in currently available packaging materials, which may be made of not only pure aluminum but also aluminum alloys. The thickness of the aluminum foil used in the aluminum foil laminate is not particularly limited and can be arbitrarily set, but is preferably 5 μm or more and 100 μm or less, and more preferably 7 μm or more and 65 μm or less. Particularly when the aluminum foil is thick, there are fewer pinholes and tears during molding in the aluminum foil laminate, which is preferable. When the aluminum foil is thicker than 100 μm, the rigidity becomes too large and the flexibility of the aluminum foil laminate becomes poor, so there is a risk of heat seal unevenness due to rubbing or the like. When the aluminum foil is thinner than 5 μm, pinholes are likely to occur in the aluminum foil, and the function as a packaging material may deteriorate. To control the thickness of the aluminum foil within the above range, casting and rolling may be performed according to conventional methods. Further, heat treatment may be appropriately performed for the purpose of homogenizing the aluminum foil or the like. <Resin layer>

[0027] In the present invention, the resin layer is a layer made of resin that is laminated with the above aluminum foil. The resin layer may be provided on one side or both sides of the aluminum foil, and each resin layer may be a single layer, or may have a multilayer structure in which a plurality of resin layers are laminated. Further, in the present invention, when resin layers are laminated on both sides of the aluminum foil, the resin types and thicknesses of the resin layers formed on the other sides may be the same or different.

[0028] The resin layer may be a resin film or a resin coat layer. The type of resin can be appropriately selected according to the performance requirements such as printability, strength, and heat adhesiveness required for the packaging material. Particularly, in the present invention, the resin layer may have heat adhesiveness. By having heat adhesiveness in the resin layer, it becomes easy to form into a package by processing such as heat sealing.

[0029] Also, it is preferable that the resin layer is formed of two or more resin layers. When there are two or more resin layers, it becomes possible to compensate for characteristics that cannot be achieved by only one layer with other layers.

[0030] In the present invention, known resin materials can be used for the resin layer, and there is no particular limitation. Specifically, for example, one or more resins selected from known resins such as epoxy, nitrocellulose, polyvinyl butyral, phenolic resin, maleic acid resin, alkyd resin, chlorinated polypropylene resin, vinyl chloride-vinyl acetate copolymer resin, acrylic resin, and modified olefin resin can be used. Further, for example, one or more known adhesives selected from polyurethane-based adhesives, epoxy-based adhesives, acrylic-based adhesives, polypropylene-based adhesives, polyester-based adhesives, vinyl chloride-based adhesives, vinyl chloride-vinyl acetate copolymer-based adhesives, and modified olefin-based adhesives can be used. Furthermore, for example, known resin films made of one or more resins selected from polyethylene-based, polypropylene-based, polyester-based, polyamide (nylon)-based, (meth)acrylic-based, polyvinyl chloride-based, polystyrene-based, polyvinylidene chloride-based, saponified ethylene-vinyl acetate copolymer, polyvinyl alcohol, polycarbonate-based, polyvinyl acetate-based, and acetal-based can be used.

[0031] When laminating a resin film on an aluminum foil as the resin layer, known adhesion and lamination methods can be widely adopted for bonding the two, and there is no particular limitation. Specifically, examples include the dry lamination method using a two-component curable adhesive such as polyester urethane-based or polyester-based, the coextrusion method, the extrusion coating method, the extrusion lamination method, the heat seal method, or the heat lamination method using an anchor coating agent.

[0032] As a method of laminating a resin coating layer as a resin layer on an aluminum foil, any known method can be used. For example, 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, etc., can be used to apply a coating agent. Or a coating method combining two or more of the above coating methods may be used. Further, heat treatment for drying or reaction may be performed after coating.

[0033] In addition, the resin coating layer may be subjected to surface treatment such as ion plasma treatment, ion plating treatment, sputtering treatment, vapor deposition treatment, or plating treatment. Further, a method of laminating a resin coating layer combining one or more of the above coating methods and one or more surface treatment methods may be used.

[0034] In addition, for the resin coating layer of the aluminum foil, surface modification by plasma treatment, fatty acid, silane coupling agent, etc., and modified products formed using acids and / or alkalis, etc., can be preferably used, and there is no particular limitation.

[0035] In the present invention, the thickness of the resin layer can be appropriately determined according to the characteristics required for the package using the aluminum foil laminate. For example, per resin layer, it is preferably in the range of 1 μm or more and 250 μm or less. Also, the forming amount when coating the resin layer is not particularly limited, but it can be set in the range of 0.1 g / m 2 or more and 100 g / m 2 or less, preferably 1 g / m 2 or more and 10 g / m 2 or less, more preferably 1 g / m 2 or more and 5 g / m 2 or less can be adopted.

[0036] The separation method of the present invention successively includes a recess-providing step of providing a recess in the aluminum foil laminate described above, a crushing step of crushing the aluminum foil laminate to obtain crushed pieces, and an immersion step of immersing the crushed pieces in a release agent solution. Hereinafter, each step will be described in detail.

[0037] <Recess-providing step> The recess-providing step is a step of providing a recess in the aluminum foil laminate. The method of providing a recess in the aluminum foil laminate is not particularly limited, and methods such as laser, blade, needle, sandblasting, and press molding can be used. For example, preferably, there is a method of passing the aluminum foil laminate through a crusher provided with one or more pairs of rolls having convex portions provided on the surface of at least one of the rolls, and this method may be performed dry or wet. When performed wet, if it is performed in a release agent solution or the surface of the roll provided with convex portions is wetted with the release agent solution, the release agent solution can be driven into the inside of the aluminum foil laminate while providing the recess.

[0038] The shape of the convex portion provided on the roll surface is not particularly limited, but it is preferably a shape with a rounded tip or a pointed tip. When the tip of the convex portion is flat, fine punched chips are generated, which may reduce the recovery rate, make it difficult to separate the peeled aluminum foil pieces and resin pieces, and there is a risk that they may remain as foreign substances in each other even after separation. In particular, it is preferable to form a recess in the aluminum foil laminate with a needle having a pointed tip shape for the convex portion. Specific examples of the pointed tip shape include a needle shape, a conical shape, a polygonal pyramid shape, a blade shape, and a serrated shape. When the recess is to penetrate, the tip of these shapes may be rounded. When the recess is not to penetrate, since the convex portion is provided without strongly pressing it in, it is preferable that the convex portion has a sharp shape. The arrangement pattern of the convex portions may be appropriately arranged according to the pattern of the recesses, and may be regular or random. In order to provide at least one or more recesses in each crushed piece of the aluminum foil laminate, the interval between the convex portions is preferably smaller than the size of the crushed piece.

[0039] Also, in the recess-forming step, the aluminum foil laminate is sent to a subsequent pulverization step using at least a pair of rolls, and recesses are formed in the aluminum foil laminate simultaneously with the feeding by convex portions provided on the surface of at least one of the rolls. This is preferable. Thereby, while forming recesses in the aluminum foil laminate, the aluminum foil laminate can be sent to the next step, and it is not necessary to provide a separate device (such as a conveyor or a blower) only for sending the aluminum foil laminate to the next step.

[0040] Also, in the recess-forming step, it is preferable that the recesses are formed by at least one of through-holes penetrating the aluminum foil laminate and cuts. For example, as a method of forming through-holes penetrating the aluminum foil laminate, a method of making holes with a blade, a needle, or the like can be mentioned. As a method of making a cut in the aluminum foil laminate, a method of cutting a part of the aluminum foil laminate with a laser, a blade, or the like to provide a cut can be mentioned.

[0041] <Recess> In the recess forming process, the recesses provided in the aluminum foil laminate include not only non-through-shaped recesses such as depressions and grooves, but also those that penetrate the aluminum foil of the aluminum foil laminate, through holes and cuts that penetrate all layers of the aluminum foil laminate, etc. By using the release agent solution described later, the aluminum foil and the resin layer can be easily peeled off with little dissolution of the aluminum foil. Also, by previously providing recesses in the aluminum foil laminate, the release agent solution can easily penetrate into the resin layer from areas other than the edges of the crushed pieces, and the time required for peeling is shortened. Such recesses may penetrate the aluminum foil laminate, such as through holes and cuts, as long as they are sunken from the surface where the recesses are provided, or may not penetrate the aluminum foil laminate, such as non-through holes, groove shapes, and depression shapes. When the recess does not penetrate the aluminum foil laminate, it may be a recess that reaches the interface between the resin layer and the aluminum foil as shown in FIG. 3, or a recess that penetrates one resin layer but does not penetrate the other resin layer as shown in FIG. 4. As shown in FIGS. 1 and 2, when the hole-shaped recess 40 and the cut-shaped recess 50 penetrate the crushed pieces 10 of the aluminum foil laminate, the release agent solution can easily penetrate from both sides. On the other hand, when a cut-shaped recess 55 in the form of a groove that does not penetrate the crushed pieces 10 of the aluminum foil laminate is provided as shown in FIG. 3, the strength of the crushed pieces 10 is higher than when the recess penetrates the aluminum foil laminate, and even when mechanically stirred in the immersion process described later, deformation such as tearing or bending of the crushed pieces 10 is less likely to occur. Also, when cut-shaped recesses 55 that do not penetrate the aluminum foil laminate having resin layers 30 on both sides of the aluminum foil 20 are provided on both sides, it is preferable to shift the positions of the cut-shaped recesses 55 on both sides as shown in FIG. 4 to maintain the strength of the crushed pieces 10. When a non-penetrating cut-shaped recess 55 is provided in the aluminum foil laminate having an adhesive layer 60 between the aluminum foil 20 and the resin layer 30, as shown in FIG. 5, when it reaches both the interface between the aluminum foil 20 and the adhesive layer 60 and the interface between the resin layer 30 and the adhesive layer 60, the release agent solution can penetrate more easily.

[0042] When providing a concave portion in the form of a depression or a through-hole, at least one or more concave portions may be provided per one crushed piece, but it is more preferable that a plurality of concave portions are arranged in a regular or random pattern. As a specific number of the concave portions, in order to promote the penetration of the release agent solution, it is preferably 0.1 or more per 1 mm 2 and more preferably 1 or more. Also, from the viewpoint of the strength of the crushed piece, it is preferably 100 or less and more preferably 10 or less per 1 mm 2 . The size of the hole is not particularly limited, but it is preferably 0.1 μm or more and 100 μm or less in diameter, and more preferably 1 μm or more and 10 μm or less. When the diameter is 0.1 μm or more, the release agent solution easily penetrates. Also, when the diameter is 100 μm or less, curling at the edge of the hole is suppressed, and the peeled aluminum foil piece and the resin piece are less likely to be entangled. When providing a groove-shaped or notch-shaped concave portion, the length of the concave portion depends on the size of the crushed piece, but is preferably 0.2 mm or more and 30 mm or less, and more preferably 0.5 mm or more and 20 mm or less. Also, the interval between a plurality of substantially parallel concave portions is preferably 0.1 mm or more and 5 mm or less. The direction of the notch is not particularly limited, and may be parallel to each side of the crushed piece or may be an oblique direction such as a diagonal direction. Also, it may be only parallel in one direction, or a combination of notches in a plurality of intersecting directions may be used.

[0043] <Crushing process> The crushing process is a process of crushing the aluminum foil laminate. In the crushed pieces of the finely crushed aluminum foil laminate, it is time-consuming to individually provide recesses, and it is difficult to uniformly provide recesses when providing them in a batch. Therefore, the crushing process is carried out simultaneously with or after the recess-providing process. The shape of the crushed pieces by the crushing process is not particularly limited, but usually they can be made to have a certain size and it is difficult for end materials to occur, so it is preferable to finely cut them into a quadrilateral such as a rectangle by cutting. Also, it is preferable that the crushed pieces have little deformation such as bending. If the crushed pieces have no deformation such as bending and are flat or have a gentle bending degree of bending, the peeled resin piece and the aluminum foil piece are less likely to be entangled and are easy to separate.

[0044] The size of the crushed pieces is preferably such that, assuming a flattened state is regarded as a substantially rectangular shape such as a rectangle or a rounded rectangle, one side is 1 mm or more and 50 mm or less, and more preferably 10 mm or more and 50 mm or less. By setting the size of the crushed pieces to 1 mm or more, separation due to the difference in specific gravity between the peeled resin pieces and the aluminum foil pieces becomes easier. Also, by setting the size of the crushed pieces to 50 mm or less, it becomes possible to increase the filling amount of the crushed pieces in the peeling liquid. The crushing method is not particularly limited as long as it can crush the aluminum foil laminate into a predetermined size. For example, punching with a fixed blade, punching with a fixed blade provided on the surface of a rotating shaft (see Fig. 7), crushing with a rotating blade, etc. can be applied. In order to prevent deformation such as bending of the crushed pieces, punching with a fixed blade that can be trimmed by cutting or punching with a fixed blade provided on the surface of a rotating shaft is preferred. For such a crushing method, a known crusher can be employed.

[0045] Also, the crushing process may be performed intermittently after the above-described recessed portion forming process, or may be performed continuously. For example, as shown in Fig. 7, by using a crusher provided with a convex portion 90 on at least one surface of a roll 80 for feeding the aluminum foil laminate 70 into the crushing process, the aluminum foil laminate 75 provided with the hole-shaped recesses 40 is fed toward the rotating blade 100, passes between the rotating blades 100, and is crushed to obtain the crushed pieces 10.

[0046] <Immersion process> The immersion process is a process of immersing the crushed aluminum foil laminate in a peeling agent solution. By this process, it becomes easier to peel the aluminum foil pieces and the resin pieces from the crushed pieces. As the peeling agent solution to be immersed, as described later, a solution containing an acid, a carboxylic acid compound, and water is used.

[0047] In the immersion process, in order to promote peeling, stirring, ultrasonic irradiation, etc. may be performed. When stirring is performed, since there is a risk of deformation of the crushed pieces due to shear or entanglement of the crushed pieces with the stirring blades, a stirring method that does not use stirring blades, such as stirring by bubbling, is preferred. When separating the aluminum foil pieces and the resin pieces peeled in the release agent solution, after peeling, it is preferable to stop stirring and let it stand still in order to easily separate them by sinking the aluminum foil pieces and floating the resin pieces. The time for immersion in the release agent solution should be such that the dissolution of the aluminum foil does not progress and the aluminum foil and the resin layer can be peeled off. It is preferably 1 minute or more and 30 minutes or less, and more preferably 5 minutes or more and 15 minutes or less. If the immersion time in the release agent solution is less than 1 minute, there is a risk that peeling may not be sufficient. If it exceeds 30 minutes, the processing time becomes long and large-scale recycling may be difficult. Also, the liquid temperature of the release agent solution to be immersed is not particularly limited, but it is preferably 10°C or more and 90°C or less, and more preferably 25°C or more and 60°C or less. If the liquid temperature is less than 10°C, it takes time for peeling. If it exceeds 90°C, there is a risk that the dissolution of the aluminum foil will progress and the recovery rate will decrease. <Other processes>

[0048] Before immersion, it is preferable to perform optical sorting, magnetic sorting, eddy current sorting, etc. on the crushed pieces to remove foreign substances in advance.

[0049] The method for separating (sorting) the crushed pieces of the peeled resin layer (resin pieces) and the crushed pieces of the aluminum foil (aluminum foil pieces) is not particularly limited. For example, sedimentation separation, centrifugal separation using a wet cyclone, etc. can be mentioned. If the resin pieces are made of a resin with a small specific gravity such as polyolefin, when peeling progresses, the resin pieces will float on the liquid surface of the release agent solution while the aluminum foil pieces will sink, so they can be easily separated. When the specific gravity difference between the resin pieces and the release agent solution is small, they can be separated by redispersing them in a heavy liquid having an appropriate specific gravity after peeling.

[0050] <Release agent solution> As described later, a release agent solution having a specific composition is used in the dipping process. The release agent solution will be described in detail below.

[0051] The release agent solution used in the dipping process contains: (Release agent solution A) at least one ammonium salt composed of ammonium formate and ammonium acetate in an amount of 1.2% by mass or more and 75% by mass or less; one or more first acids selected from the group consisting of nitric acid, sulfuric acid, phosphoric acid, formic acid, and acetic acid in an amount of 2% by mass or more and 30% by mass or less; and water in an amount of 23% by mass or more and 96.8% by mass or less. The total of the ammonium salt, the first acid, and the water is 100% by mass or less in the release agent solution A, and the content ratio obtained by dividing the content (% by mass) of the ammonium salt by the content (% by mass) of the first acid is 0.1 or more and 37.5 or less. (Release agent solution B) a second acid composed of at least one of nitric acid and formic acid in an amount of 2% by mass or more and 35% by mass or less; one or more third acids selected from the group consisting of polycarboxylic acids, hydroxy acids, polycarboxylate salts, and hydroxycarboxylate salts in an amount of 0.1% by mass or more and 35% by mass or less; and water in an amount of 40% by mass or more and 97.7% by mass or less. The total of the second acid, the third acid, and the water is 100% by mass or less in the release agent solution B, and the content ratio obtained by dividing the content (% by mass) of the second acid by the content (% by mass) of the third acid is 0.057 or more and 30 or less. It is either of the above.

[0052] That is, by using either the release agent solution A or the release agent solution B, the aluminum foil and the resin layer can be efficiently separated from the aluminum foil laminate. The composition and the like of each release agent solution will be described in detail below.

[0053] (Release agent solution A) The above-described release agent solution A contains 1.2 mass% or more and 75 mass% or less of an ammonium salt composed of at least one of ammonium formate and ammonium acetate, 2 mass% or more and 30 mass% or less of one or more first acids selected from the group consisting of nitric acid, sulfuric acid, phosphoric acid, formic acid, and acetic acid, and 23 mass% or more and 96.8 mass% or less of water, and the total of the ammonium salt, the first acid, and the water is 100 mass% or less in the release agent solution A, and the content ratio obtained by dividing the content (mass%) of the ammonium salt by the content (mass%) of the first acid is 0.1 or more and 37.5 or less.

[0054] <First acid> The first acid used in the release agent solution A is one or more acids selected from the group consisting of nitric acid, sulfuric acid, phosphoric acid, formic acid, and acetic acid. Nitric acid is a strong acid with an acid dissociation constant pKa of -1.4 at 25°C. Nitric acid penetrates from the resin side or end face of the aluminum foil laminate and, when it eventually reaches the interface between the resin and the aluminum foil, it cleaves the bond between the functional groups on the aluminum foil surface and the resin surface. Thereafter, nitric acid reacts violently with aluminum and dissolves aluminum. Therefore, while nitric acid has the effect of peeling the resin layer from the aluminum foil, using nitric acid alone would lead to an undesirable result of eluting a large amount of aluminum foil. This is the same in the case of sulfuric acid, which is also a strong acid. Therefore, in the release agent solution A, by using the ammonium salt described below, the ammonium salt is adhered to the aluminum surface to suppress the elution of aluminum, and by adjusting the content ratio of the first acid and the ammonium salt to a specific range, both the peeling effect of the first acid and the effect of reducing the elution amount of aluminum by the ammonium salt can be exhibited.

[0055] Hydrochloric acid, which is a common inorganic acid along with nitric acid, is a strong acid like nitric acid and formic acid, but since it has chloride ions, using it as the first acid would cause the elution of aluminum to proceed more strongly. Therefore, hydrochloric acid is not suitable for peeling the aluminum foil laminate because, even if an ammonium salt is added, it reacts violently with aluminum and dissolves aluminum.

[0056] Phosphoric acid is an acid with a medium acid dissociation constant pKa of 2.2 between weak acids and strong acids. While it has a stripping effect similar to strong acids such as nitric acid and sulfuric acid, it will dissolve aluminum. Therefore, when using phosphoric acid, it is also necessary to add an ammonium salt as in the case of nitric acid to reduce the elution of aluminum.

[0057] Formic acid is different from strong acids such as hydrochloric acid and nitric acid. It does not react violently with aluminum foil and cause the disappearance of aluminum during the separation from the resin layer. Also, formic acid is a weak acid (pKa 3 - 7) with an acid dissociation constant pKa of 3.75. Among monovalent aliphatic carboxylic acids, it shows the strongest acidity and has the property that protons are easily dissociated. Therefore, in the stripping agent solution A, formate ions, etc. cut the adhesion between the aluminum interface and the resin layer interface, and further promote the separation of the aluminum foil and the resin layer.

[0058] Thus, formic acid has the effect of peeling the aluminum foil and the resin layer from the aluminum foil laminate. On the other hand, formic acid also has an undesirable effect of eluting aluminum, although not as much as nitric acid. Therefore, it is necessary to add an ammonium salt as in the case of nitric acid to reduce the elution of aluminum.

[0059] Acetic acid is a weak acid (pKa 3 - 7) with an acid dissociation constant pKa of 4.8. Therefore, acetic acid has a lower ability to cut the adhesion between the aluminum interface and the resin layer interface and separate the aluminum foil and the resin layer compared to formic acid and nitric acid. On the other hand, when ammonium formate or ammonium acetate exists in an acetic acid aqueous solution, the dissociated formate ions or acetate ions combine with the protons released by acetic acid to free formic acid or acetic acid, and such formic acid or acetic acid works advantageously to cut the adhesion between the aluminum interface and the resin layer interface. Therefore, although the elution of aluminum is small, the peeling of the aluminum foil and the resin layer by the first acid is promoted.

[0060] In the release agent solution A, the content of the first acid is 2% by mass or more and 30% by mass or less. If the content of the first acid is less than 2% by mass, there is a risk that the above-mentioned release effect cannot be sufficiently obtained. On the other hand, if the content of the first acid exceeds 30% by mass, the elution of aluminum will further progress, and there is a risk that the effect of reducing the elution amount of aluminum by the ammonium salt cannot be sufficiently obtained.

[0061] Also, the content of the first acid in the release agent solution A is such that the content ratio obtained by dividing the content of the ammonium salt (mass%) by the acid content (mass%) (hereinafter also referred to as the "ammonium salt / acid content ratio") is 0.1 or more and 37.5 or less, preferably 2 or more and 30 or less, more preferably 5 or more and 15 or less, and even more preferably 5 or more and 10 or less.

[0062] The release agent solution A needs to have an ammonium salt / acid content ratio of 0.1 or more and 37.5 or less. If the ammonium salt / acid content ratio exceeds 37.5, the effect of reducing the elution amount of aluminum by the ammonium salt (the protective effect of aluminum) will progress excessively, and the release effect by the first acid cannot be sufficiently obtained. On the other hand, if the ammonium salt / acid content ratio is less than 0.1, the release effects of nitric acid, sulfuric acid, phosphoric acid, formic acid, and acetic acid will progress excessively, resulting in the inconvenience that the elution amount of aluminum increases too much. Therefore, in the release agent solution A, the ammonium salt / acid content ratio is 0.1 or more and 37.5 or less, more preferably 0.2 or more and 4.5 or less, and even more preferably 0.3 or more and 1.0 or less.

[0063] The first acid in the release agent solution A may be composed of any one component (single component) of nitric acid, sulfuric acid, phosphoric acid, formic acid or acetic acid, or may be composed of a mixture of two or more acids selected from the group consisting of nitric acid, sulfuric acid, phosphoric acid, formic acid and acetic acid. When mixing formic acid, which is a weak acid, with nitric acid, which is a strong acid, formic acid also functions as a weak base and has the effect of suppressing the elution of aluminum. The mixing ratio of nitric acid, sulfuric acid, phosphoric acid, formic acid and acetic acid is not particularly limited as long as the ammonium salt / acetic acid content ratio is in the range of 0.1 or more and 37.5 or less, and can be freely set.

[0064] <ammonium salt> The ammonium salt used in the release agent solution A is an ammonium salt composed of at least one of ammonium formate and ammonium acetate. The effect of reducing the elution of aluminum by the ammonium salt is manifested because the ammonium ions and carboxylic acid ions of the ammonium salt generate hydrates with water (water molecules) described later and then adsorb on the surface of the aluminum foil.

[0065] The ammonium salt has not only the effect of reducing the elution amount of aluminum but also the effect of promoting peeling. Specifically, the formic acid or acetic acid of the ammonium salt is liberated by the protons released by an acid such as acetic acid, and the liberated acid promotes the separation of the resin and the aluminum foil. As described above, although formic acid and acetic acid are weak acids, they have the ability to peel the aluminum foil and the resin. Therefore, the ammonium salt plays a role of supplementing the acid component consumed during peeling with the acid liberated from the ammonium salt.

[0066] The content of the ammonium salt in the release agent solution A is 1.2% by mass or more and 75% by mass or less, more preferably 5 to 75% by mass, and even more preferably 5 to 45% by mass. If the content of the ammonium salt is less than 1.2% by mass, there is a possibility that the above-mentioned effect of reducing the elution amount of aluminum cannot be sufficiently obtained. On the other hand, if the content of the ammonium salt exceeds 75% by mass, the adhesion of the ammonium salt to the aluminum foil becomes excessive, and there is a possibility that the peeling effect between the aluminum foil and the resin layer cannot be sufficiently obtained.

[0067] In the present invention, the ammonium salt is ammonium formate and / or ammonium acetate. Since formic acid released from ammonium formate in the coexistence with the first acid has a greater peeling effect on the aluminum foil and the resin layer than acetic acid released from ammonium acetate in the coexistence with the first acid, it is more preferable to use ammonium formate as the ammonium salt.

[0068] Examples of salts other than ammonium salts include sodium salts and potassium salts that are alkali metal salts, and salts of polyvalent carboxylic acids and hydroxy acids such as calcium salts and ammonium salts. However, when using the above salts, when the aluminum separated and recovered from the aluminum laminate is melted and reused as an aluminum ingot, there is a risk that the metal will be mixed into the aluminum as an impurity.

[0069] For example, sodium, which is an alkali metal, is taken into aluminum as an impurity when heating and melting aluminum. Aluminum is usually cast with a high purity of 98 to 99.9% by mass and further rolled into an aluminum foil. Therefore, even if a very small amount of metal salt impurities are taken in, the purity and quality will deteriorate. Therefore, in the present invention, as the salt used to adjust (reduce) the elution amount of aluminum, it does not contain metal components such as alkali metals and alkaline earth metals other than aluminum, and decomposes during casting to form NO X An ammonium salt, which is a salt that becomes a gas such as CO2, is most preferable.

[0070] In the release agent solution A, the effect of reducing the elution amount of aluminum by the ammonium salt is exhibited because ammonium ions and carboxylate ions of the ammonium salt form hydrates with water (water molecules) described later and then adsorb on the surface of the aluminum foil. Since functional groups such as carboxyl groups, carbonyl groups, and hydroxyl groups exist on the surface of the aluminum foil, the reaction of the acid with aluminum is suppressed by the attachment of the above hydrates to these functional groups.

[0071] <Water> In the release agent solution A, water is contained in an amount of 23% by mass or more and 96.8% by mass or less. However, the total of the first acid, the ammonium salt, and water needs to be 100% by mass or less in the release agent solution.

[0072] When water is present in the release agent solution A, the ammonium salt forms a hydrate with water molecules, and the attachment of the hydrate to the surface of the aluminum foil exhibits the effect of reducing the elution amount of aluminum. Furthermore, the ammonium salt can be dissolved in water and can also dissociate the protons of the first acid in water. Therefore, the release agent solution A is preferably a release agent solution in which water is moderately present, and the amount of the water is 23% by mass or more and 96.8% by mass or less in the release agent solution A, more preferably 45% by mass or more and 90% by mass or less, and even more preferably 65% by mass or more and 90% by mass or less. When the amount of water is within the above range, the effect of reducing the elution amount of aluminum is made sufficient by sufficiently dissolving the ammonium salt in water, and furthermore, the release of the aluminum foil and the resin by the first acid can be effectively performed, which is preferable.

[0073] <Remainder> In the release agent solution A, when the total of the first acid, the ammonium salt, and water is less than 100% by mass, the remainder may contain one or more organic solvents selected from the group consisting of ketones, ethers, alkylbenzenes, dioxolanes, cycloalkanes, and carboxylic acid esters. This is because ketones, ethers, alkylbenzenes, dioxolanes, cycloalkanes, and carboxylic acid esters also penetrate into the resin layer and have the effect of promoting the release of the resin layer from the aluminum foil.

[0074] Examples of the ketone include acetone, methyl ethyl ketone, diethyl ketone, methyl propyl ketone, methyl isobutyl ketone, methyl amyl ketone, cyclohexanone, isophorone, acetophenone, benzophenone, etc. It is often used as a true solvent for the resin coating agent, and it is preferable to use methyl ethyl ketone from the viewpoint of excellent release solubility of the resin layer.

[0075] Ethers include, for example, dimethyl ether, ethyl methyl ether, diethyl ether, diphenyl ether, ethylene oxide, tetrahydrofuran (THF), furan, 1,4-dioxane, anisole, benzofuran, dibenzofuran, crown ether, etc. Considering the miscibility with water, it is preferable to use tetrahydrofuran (THF), furan or 1,4-dioxane.

[0076] Alkylbenzenes include, for example, xylene, toluene, ethylbenzene, cumene, p-cymene, etc. They are often used as true solvents for resin coating agents. From the perspective of excellent stripping solubility of the resin, it is preferable to use xylene or toluene.

[0077] Dioxolane specifically includes 1,3-dioxolane. Since it has high miscibility with water and can penetrate well into the resin layer, it can be preferably used.

[0078] Cycloalkanes include cycloalkanes having 5 to 12 carbon atoms such as cyclopentane, cyclohexane, methylcyclohexane, cycloheptane, cyclooctane, cyclododecane, etc. They are often used as true solvents for resin coating agents. From the perspective of excellent stripping solubility of the resin, it is preferable to use methylcyclohexane.

[0079] As the carboxylic acid ester, a carboxylic acid ester composed of a formate ester having 9 or less carbon atoms and / or an acetate ester having 9 or less carbon atoms can be used. Specifically, for example, methyl formate, ethyl formate, propyl formate, butyl formate, pentyl formate, hexyl formate, isoamyl formate, heptyl formate, octyl formate, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, pentyl acetate, hexyl acetate, heptyl acetate, etc. can be mentioned. These carboxylic acid esters are carboxylic acid derivatives that generate carboxylic acids in warm water, and are also preferably used because they exhibit the effect of reducing the elution amount of aluminum by adhering to the surface of the aluminum foil described later. In particular, butyl acetate, ethyl acetate, and isoamyl formate can be more preferably used because of their excellent solubility in resins.

[0080] Thus, when the release agent solution A contains additives of ketone, ether, alkylbenzene, dioxolane, cycloalkane, and carboxylic acid ester, it is not particularly limited as long as the content ratio of ammonium salt / acetic acid is 0.1 or more and 37.5 or less, but it is preferably 0.1% by mass or more and 50% by mass or less in the release agent solution A in total of the additives, and more preferably 0.1% by mass or more and 10% by mass or less in order to be uniformly mixed in the release agent solution A.

[0081] <Other additives> The release agent solution A contains an ammonium salt, a first acid, and water, and as long as the ammonium salt / acetic acid ratio is 0.1 or more and 37.5 or less, further addition of a polyvalent carboxylic acid can reduce further elution of aluminum.

[0082] Polycarboxylic acids adhere to the surface of the aluminum foil through carboxyl groups or hydroxyl groups and exhibit an effect of reducing the elution amount of aluminum, similar to ammonium salts. In particular, hydroxyacids such as tricarboxylic acids like citric acid and having a hydroxyl group preferably adhere to the aluminum foil after forming a hydrate, so that the elution amount of aluminum can be reduced. Polycarboxylic acids, whether dicarboxylic acids, tricarboxylic acids, or their salts, exhibit the same effect. In the case of salts, it is necessary to use ammonium salts that do not mix as impurities during aluminum dissolution. For example, as metal salts, there are sodium salts, potassium salts, calcium salts, etc., which are alkaline earth metals. However, when using metal salts, they cannot be applied because they are mixed as impurities other than aluminum during the production of aluminum ingots.

[0083] Polycarboxylic acids are one or more components selected from the group consisting of hydroxyacids, polycarboxylic acid salts, and hydroxyacid salts. For example, as hydroxyacids, lactic acid, citric acid, malic acid, tartaric acid, glycolic acid, mandelic acid, glyceric acid, salicylic acid, ascorbic acid, and gluconic acid can be applied. Among these, it is more preferable to apply citric acid, lactic acid, malic acid, tartaric acid, and gluconic acid, which are more likely to exhibit a chelating effect as described later. Also, as polycarboxylic acids, for example, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, phthalic acid, isophthalic acid, terephthalic acid, maleic acid, and fumaric acid, which are dicarboxylic acids, can be applied. For tricarboxylic acids, aconitic acid and trimesic acid can be applied. Among these, those having a structure in which carboxylic acids are close to each other, such as maleic acid, are more preferable because they are more likely to produce a chelating effect.

[0084] In the release agent solution A, the addition amount of polycarboxylic acid can be added within a range that does not impair the release action. For example, when adding polycarboxylic acid for the purpose of assisting the effect of reducing the elution amount of aluminum, it is preferably 10% by mass or less in the release agent solution A.

[0085] (Release Agent Solution B) The above release agent solution B contains 2% by mass or more and 35% by mass or less of a second acid composed of at least one of nitric acid and formic acid, 0.1% by mass or more and 35% by mass or less of one or more third acids selected from the group consisting of polyvalent carboxylic acids, hydroxy acids, polyvalent carboxylates, and hydroxy carboxylates, and 40% by mass or more and 97.7% by mass or less of water, and the total of the second acid, the third acid, and the water is 100% by mass or less in the release agent solution B, and the content ratio obtained by dividing the content (% by mass) of the second acid by the content (% by mass) of the third acid is 0.057 or more and 30 or less.

[0086] <Second Acid> In the above release agent solution B, the second acid is an acid composed of at least one of nitric acid and formic acid.

[0087] Nitric acid is a strong acid with an acid dissociation constant pKa of -1.4 at 25°C. Nitric acid penetrates from the resin side or the end face of the aluminum foil laminate and, when it reaches the interface between the resin and the aluminum foil, cuts the bond between the functional groups on the surface of the aluminum foil and the resin surface. After that, nitric acid reacts violently with aluminum and dissolves aluminum. Therefore, while nitric acid has the effect of peeling the resin and the aluminum foil, using nitric acid alone will lead to an undesirable result of eluting a large amount of aluminum foil. Therefore, in the release agent solution B, by using the third acid described below, the third acid is attached to the aluminum surface to suppress the elution of aluminum, and by adjusting the content ratio of nitric acid and the third acid to a specific range, both the peeling effect of nitric acid and the effect of reducing the elution amount of aluminum by the third acid can be expressed.

[0088] Hydrochloric acid, which is a common inorganic acid along with nitric acid, is also a strong acid like nitric acid and formic acid, but since it has chloride ions, using it as the second acid will further promote the elution of aluminum. Therefore, even if a third acid is added, hydrochloric acid will react violently with aluminum and dissolve aluminum, so it is not suitable for peeling the aluminum foil laminate.

[0089] Formic acid, unlike strong acids such as hydrochloric acid and nitric acid, does not react violently with aluminum foil and cause the disappearance of aluminum during separation from the resin layer. Also, formic acid is a weak acid (pKa 3 - 7) with an acid dissociation constant pKa of 3.75, but it exhibits the strongest acidity among monovalent aliphatic carboxylic acids and has the property that protons are easily dissociated. Therefore, in the release agent solution B, formate ions, etc. cut the adhesion between the aluminum interface and the resin layer interface, and further promote the separation of the aluminum foil and the resin layer.

[0090] Thus, formic acid has the effect of peeling the aluminum foil and the resin from the aluminum foil laminate. On the other hand, formic acid, although not as strong as nitric acid alone, also has an undesirable effect of eluting aluminum. Therefore, like nitric acid, it is necessary to add a third acid to reduce the elution of aluminum.

[0091] In the release agent solution B, the content of the second acid, which is the combined content of nitric acid and formic acid in the release agent solution B, is 2% by mass or more and 35% by mass or less. If the content of the second acid is less than 2% by mass, there is a risk that the above-mentioned peeling effect cannot be sufficiently obtained. On the other hand, if the content of the second acid exceeds 35% by mass, the elution of aluminum will further progress, and there is a risk that the effect of reducing the elution amount of aluminum by the third acid cannot be sufficiently obtained.

[0092] Therefore, the content of the second acid in the release agent solution B is not particularly limited as long as the content ratio (hereinafter, also referred to as "the content ratio of the second acid / the third acid"), which is the content of the second acid (% by mass) described below divided by the content of the third acid (% by mass), is 0.057 or more and 30 or less, but it is preferably 2% by mass or more and 35% by mass or less, more preferably 3% by mass or more and 10% by mass or less, and even more preferably 4% by mass or more and 10% by mass or less.

[0093] In the release agent solution B, the second acid needs to have a content ratio of the second acid / third acid of 0.057 or more and 30 or less. If the content ratio of the second acid / third acid is less than 0.057, the effect of reducing the elution amount of aluminum by the second acid (the protective effect of aluminum) will progress excessively, and the release effect by the second acid cannot be sufficiently obtained. On the other hand, if the content ratio of the second acid / third acid exceeds 30, the release effect of nitric acid or formic acid will progress excessively, and the inconvenience that the elution amount of aluminum will increase too much will also occur. Therefore, in the release agent solution B, the content ratio of the second acid / third acid is preferably 0.057 or more and 30 or less, more preferably 0.3 or more and 6.0 or less, and even more preferably 0.3 or more and 2.3 or less. Although the lower limit of the content ratio of the second acid / third acid is 0.057, it is the value of the content ratio obtained by dividing the lower limit of 2% by mass of the second acid by the upper limit of 35% by mass of the third acid, and strictly speaking, it is 2÷35 = 0.057143. In the present invention, for simplicity, the value of four digits or less after the decimal point is ignored, and 0.057 is simply set as the lower limit of the content ratio of the second acid / third acid.

[0094] The second acid may be composed of a single component of nitric acid or formic acid, or may be composed of a mixture of nitric acid and formic acid. When a weak acid, formic acid, is mixed with a strong acid, nitric acid, formic acid also functions as a weak base and has the effect of suppressing the elution of aluminum. The ratio of nitric acid to formic acid is not particularly limited as long as the content ratio of the second acid / third acid is within the range of 0.057 or more and 30 or less, and can be freely set.

[0095] <The second acid> The third acid used in the present invention means a polyfunctional acid or a polyfunctional acid salt, and specifically means a polycarboxylic acid, a hydroxy acid or a salt thereof. A typical example is citric acid. The effect of reducing the elution of aluminum by the third acid is exhibited because the hydroxyl group or carboxyl group of the third acid forms a hydrate with water (water molecules) described later and then adsorbs on the surface of the aluminum foil.

[0096] Citric acid is a hydroxy acid having three carboxyl groups and one hydroxyl group. These functional groups form hydrates and attach to the functional groups on the aluminum surface, thereby suppressing the reaction of aluminum with nitric acid or formic acid. Therefore, tartaric acid having two carboxyl groups and two hydroxyl groups, and lactic acid which is a hydroxy acid having one carboxyl group and one hydroxyl group also exhibit the same effects as citric acid. In addition, maleic acid which is a dicarboxylic acid, polycarboxylic acid derivatives (for example, fumaric anhydride), and polyfunctional acid salts which become polyfunctional acid ions when dissolved in water also exhibit the same effects.

[0097] In the release agent solution B, the content of the third acid in the release agent solution B is 0.1% by mass or more and 35% by mass or less. If the content of the third acid is less than 0.1% by mass, there is a possibility that the effect of reducing the elution amount of the above aluminum cannot be sufficiently obtained. Further, if the content of the third acid exceeds 35% by mass, the adhesion of the third acid to the aluminum foil becomes excessive, and there is a possibility that the peeling effect between the aluminum foil and the resin layer cannot be sufficiently obtained.

[0098] In the present invention, the third acid is composed of one or more components selected from the group consisting of polycarboxylic acids, hydroxy acids, polycarboxylic acid salts, and hydroxy acid salts. For example, examples of hydroxy acids include lactic acid, citric acid, malic acid, tartaric acid, glycolic acid, mandelic acid, glyceric acid, salicylic acid, ascorbic acid, gluconic acid, and the like. Among these, it is preferable to use citric acid, lactic acid, malic acid, tartaric acid, and gluconic acid which are likely to exhibit a chelating effect as described later.

[0099] Examples of polycarboxylic acids include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, phthalic acid, isophthalic acid, terephthalic acid, maleic acid, fumaric acid, etc., which are dicarboxylic acids. Examples of tricarboxylic acids include aconitic acid, trimesic acid, etc. Among these, those having a structure in which carboxylic acids are close to each other, such as maleic acid, are likely to produce a chelating effect and are preferably used.

[0100] In the present invention, as the third acid, salts of polyvalent carboxylic acids or hydroxy acids such as sodium salts, potassium salts, calcium salts, and ammonium salts of alkaline earth metals can be preferably used. Among these, it is preferable to use a salt that is not a metal salt such as diammonium hydrogen citrate. This is because aluminum separated and recovered from the aluminum laminate is usually dissolved and reused as an aluminum ingot. However, if the third acid is a metal salt containing sodium, calcium, or the like, there is a risk that the metal will be mixed into the aluminum as an impurity.

[0101] Further, if the third acid in the release agent solution B is a dicarboxylic acid derivative, for example, maleic anhydride, phthalic anhydride, phthalic acid ester, maleic acid ester, dimethyl adipate, dibutyl sebacate, diethyl glutarate, dimethyl fumarate, dioctyl adipate, glyoxylic acid can be used. Among these, substances that are easily hydrolyzed in warm water to form dicarboxylic acids are preferable, and for example, phthalic anhydride is preferably used.

[0102] The effect of reducing the elution amount of aluminum by the third acid in the release agent solution B is considered to be exhibited by physical adsorption, chemical adsorption, chelating effect, or the like. The chelating effect is exhibited when a complex is formed in such a way that a ligand having two or more coordination sites sandwiches a metal ion. Since the chelating effect involves a carboxyl group or a hydroxyl group in forming a complex structure, in order to exhibit the effect of the present invention, it is necessary to have a plurality of functional groups. Therefore, citric acid and tartaric acid, which are hydroxy acids, have both a hydroxyl group and a carboxyl group, and thus exhibit a large effect of reducing the elution amount of aluminum. In addition, polyvalent carboxylic acids having a plurality of carboxyl groups also exhibit the same effect.

[0103] <Water> In the release agent solution B, water is contained in an amount of 40% by mass or more and 97.7% by mass or less. However, the total of the second acid, the third acid, and water needs to be 100% by mass or less in the release agent solution B.

[0104] When water is present in the release agent solution B, the hydroxyl groups or carboxyl groups of the third acid form hydrates with water molecules, and the attachment of the hydrates to the surface of the aluminum foil exhibits the effect of reducing the elution amount of aluminum. In the third acid, polyfunctional acid salts such as polyvalent carboxylates and hydroxy acid salts are also dissolved in water, dissociated into polyfunctional acid ions and attached to the surface of the aluminum foil, so the effect of reducing the elution amount of aluminum is exhibited. Therefore, when the polyfunctional acid is a solid crystal, it is necessary to dissolve it in water. Accordingly, the release agent solution B is preferably a solution in which water is moderately present, and the amount of the water is 40% by mass or more and 97.7% by mass or less in the release agent solution B, more preferably 53.0% by mass or more and 97.7% by mass or less, and even more preferably 63% by mass or more and 91% by mass or less. When the amount of water is within the above range, when the third acid is a solid crystal, it is sufficiently dissolved in water to make the effect of reducing the elution amount of aluminum sufficient, and further, since the release of the aluminum foil and the resin layer by the second acid can be effectively performed, it is preferable.

[0105] <Remainder> In the release agent solution B, when the total of the second acid, the third acid, and water is less than 100% by mass, the remainder may contain one or more organic solvents selected from the group consisting of ketones, ethers, alkylbenzenes, dioxolanes, cycloalkanes, and carboxylic acid esters. This is because ketones, ethers, alkylbenzenes, dioxolanes, cycloalkanes, and carboxylic acid esters also penetrate into the resin layer and have the effect of promoting the release of the resin layer from the aluminum foil.

[0106] Examples of the ketone include acetone, methyl ethyl ketone, diethyl ketone, methyl propyl ketone, methyl isobutyl ketone, methyl amyl ketone, cyclohexanone, isophorone, acetophenone, benzophenone, etc. It is often used as a true solvent for the resin coating agent, and it is preferable to use methyl ethyl ketone from the viewpoint of excellent release solubility of the resin.

[0107] Ethers include, for example, dimethyl ether, ethyl methyl ether, diethyl ether, diphenyl ether, ethylene oxide, tetrahydrofuran (THF), furan, 1,4-dioxane, anisole, benzofuran, dibenzofuran, crown ether, etc. Considering the miscibility with water, it is preferable to use tetrahydrofuran (THF), furan or 1,4-dioxane.

[0108] Alkylbenzenes include, for example, xylene, toluene, ethylbenzene, cumene, p-cymene, etc. They are often used as true solvents for resin coating agents. From the perspective of excellent stripping solubility of the resin, it is preferable to use xylene or toluene.

[0109] Dioxolane specifically includes 1,3-dioxolane. It has high miscibility with water and can penetrate well into the resin layer, so it can be preferably used.

[0110] Cycloalkanes include cycloalkanes with 5 to 12 carbon atoms such as cyclopentane, cyclohexane, methylcyclohexane, cycloheptane, cyclooctane, cyclododecane, etc. They are often used as true solvents for resin coating agents. From the perspective of excellent stripping solubility of the resin, it is preferable to use methylcyclohexane.

[0111] As the carboxylic acid ester, 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 can be used. Specifically, for example, methyl formate, ethyl formate, propyl formate, butyl formate, pentyl formate, hexyl formate, isoamyl formate, heptyl formate, octyl formate, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, pentyl acetate, hexyl acetate, heptyl acetate, etc. can be mentioned. These carboxylic acid esters are carboxylic acid derivatives that generate carboxylic acids in warm water, and are preferably used because they exhibit an effect of reducing the elution amount of aluminum by adhering to the surface of the aluminum foil described later. In particular, butyl acetate, ethyl acetate, and isoamyl formate can be more preferably used because they are excellent in the solubility of the resin.

[0112] Thus, when the release agent solution B contains additives of ketone, ether, alkylbenzene, dioxolane, cycloalkane, and carboxylic acid ester, it is not particularly limited as long as the content ratio of the second acid / third acid is 0.057 or more and 30 or less, but it is preferable that the total of the additives is 0.1% by mass or more and 50% by mass or less in the release agent solution B, and more preferably 0.1% by mass or more and 10% by mass or less in total for the additives in order to be uniformly mixed in the release agent solution B.

[0113] <Other additives> In the release agent solution B, in the case of a monodentate ligand carboxylic acid such as formic acid or acetic acid, the chelate effect does not occur due to the physical structure, but a slight effect of reducing the elution amount of aluminum can be obtained due to the physical adsorption effect on aluminum. Therefore, as long as the second acid, the third acid, and water are contained and the content ratio of the second acid / third acid is 0.057 or more and 30 or less, further reduction of aluminum elution can be achieved by mixing acetic acid with the second acid.

[0114] The effect of reducing the elution amount of aluminum can also be achieved by using formates or acetates. Examples of these salts include sodium salts, potassium salts, calcium salts, and ammonium salts, which are alkaline earth metals. Among these, it is preferable to use salts that are not metal salts, such as ammonium formate and ammonium acetate. This is because aluminum separated and recovered from the aluminum laminate is usually dissolved and reused as aluminum ingots. However, if the third acid is a metal salt containing sodium, calcium, or the like, there is a risk that the metal will be mixed into the aluminum as an impurity. Therefore, when other additives are salts that are not metal salts as described above, the addition amount can be added within a range that does not impair the peeling action. For example, when adding for the purpose of assisting the effect of reducing the elution amount of aluminum, it is preferably 10% by mass or less in the separation solution.

[0115] In the release agent solution B, as other additives, additives such as a buffer solution can be added within a range that does not impair the peeling action. For example, the buffer solution can be expected to stabilize the pH of the separation solution. On the other hand, adding an excessive amount of the buffer solution may cause an excessive peeling effect. Therefore, in the release agent solution B, the addition amount of the buffer solution is preferably 3% by mass or less in the release agent solution B.

Examples

[0116] (Aluminum foil laminate) For the aluminum foil, a 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 Co., Ltd.: PPZ-C 96 white, solid content 34% by mass) was applied to the glossy side of the aluminum foil with a bar coater #8 so that the weight after drying was 1.5 g / m 2 and dried at 150°C for 1 minute. Next, a nitrocellulose-based coating agent (manufactured by DIC Graphics Co., Ltd.: TF842 805 black, solid content 29% by mass) was applied from above the white layer with a bar coater #3 so that the weight after drying was 0.5 g / m 2It was applied so as to achieve [a certain state], and dried at 150°C for 1 minute. Further, an epoxy-based overprint coating agent (manufactured by T&K TOKA Co., Ltd.: PT-OP varnish, solid content 33% by mass) was applied from above the ink layer with a bar coater #5, and the weight after drying was 1.5 g / m 2 It was applied so as to achieve [a certain state], and dried at 150°C for 1 minute to form an overprint layer. On the back side of the aluminum foil as well as on the shiny side, a white layer, an ink layer, and an overprint layer were applied, and a test piece with a resin layer formed on both sides having a structure of epoxy / nitrocellulose / polyolefin / aluminum foil / polyolefin / nitrocellulose / epoxy was produced.

[0117] A separating agent solution adjusted to be a separating agent solution corresponding to the separating agent solution A was used to implement the separation method of the present invention, and the following were taken as Examples 1 to 18. A separating agent solution having a composition different from both the separating agent solution A and the separating agent solution B, which is similar to the separating agent solution A, was adjusted or implemented by a method different from the separation method of the present invention, and the following were taken as Comparative Examples 1 to 9 and implemented respectively.

[0118] [Example 1] <Preparation of Separating Agent Solution, Implementation of Concave-Setting Process and Crushing Process> To a 100 mL glass bottle, 7.25 g of nitric acid (manufactured by Fujifilm Wako Pure Chemical Corporation, reagent special grade, 69% by mass), 5 g of ammonium formate (manufactured by Fujifilm Wako Pure Chemical Corporation, Wako special grade), and 87.8 g of purified water (manufactured by AS ONE Corporation, ASSWS-20) were added, and stirred at 40°C for 30 minutes to prepare a separating agent solution. Next, as the concave-setting process, on the entire surface of a 100 mm × 100 mm evaluation aluminum foil laminate, using a Thomson-type half-cut blade (high-speed steel, flat type, blade thickness 0.7 mm, blade angle 30 degrees), recesses were provided at intervals of 5 mm with parallel cuts so as not to cut the aluminum foil. This was done on both sides of the aluminum foil laminate. Next, as the crushing process, it was shredded into 20 mm × 20 mm rectangles to obtain crushed pieces.

[0119] <Implementation of Immersion Process and Evaluation of Peelability (Separation Effect)> 100 g of the prepared release agent solution was placed in a 100 mL glass bottle (mouth inner diameter × body diameter × height: φ31.9 × φ48.5 × 87 mm). Next, one rotor (manufactured by AS ONE, shape: tapered type, length 25 mm, diameter 8 mm, material: PTFE) was placed, and the opening of the glass bottle was covered with a lid so that the release agent solution would not evaporate. Further, the glass bottle containing the release agent solution was set in a six-unit heating and stirring driver (manufactured by AS ONE: HDBS-6), and it was warmed while stirring at 200 rpm until it reached 60°C. After confirming with a thermometer that the release agent solution had reached 60°C, the lid on the opening of the glass bottle was removed, the test piece was submerged in the release agent solution, and the lid was put back on.

[0120] Regarding the test piece, the time until the resin on both sides could be visually confirmed to peel off from the aluminum foil was measured. Those that peeled off within 10 minutes were designated as "A", those that peeled off within 30 minutes were designated as "B", those that peeled off within 60 minutes were designated as "C", and those that did not peel off even after exceeding 60 minutes were designated as "F", and the peelability (separation effect) of the release agent solution was evaluated. The results are shown in Table 1.

[0121] <Evaluation of Elution Property (Elution Amount Reduction Effect)> 100 mL of the release agent solution was measured and placed in a 100 mL glass bottle (mouth inner diameter 31.9 mm, body diameter 48.5 mm, height 87 mm). The glass bottle was placed in a heating and stirring driver (manufactured by AS ONE: HDBS-6), and it was heated so that the temperature of the release agent solution would reach 65°C. Next, an aluminum foil with a thickness of 20 μm (manufactured by Toyo Aluminum Co., Ltd.: 1N30 material, hard foil) cut into a square shape of 100 mm × 100 mm was gently folded into three layers so as not to have creases as much as possible, and then further folded into two layers to a size that would allow the whole to be immersed in the release agent solution. Each release agent solution was immersed under the conditions of 65°C for 60 minutes, and the weight residual ratio (%) of the aluminum foil was calculated by measuring the weight before and after immersion (see the following formula). (Formula) [Weight residual ratio (%) of aluminum foil] = [Weight of aluminum foil after immersion] / [Weight of aluminum foil before immersion] × 100

[0122] Also, in order to eliminate the influence on the weight residual ratio of trace components adhering to the surface of the aluminum foil before immersion in the release agent solution, the aluminum foil was previously immersed in methyl ethyl ketone (manufactured by Fuji Film Wako Pure Chemical Industries, Ltd.: reagent special grade) for 1 minute, the surface layer was gently wiped off with Nippon Paper Crecia paper wiper for degreasing and cleaning, and after being air-dried at room temperature for 15 minutes, it was measured. The weight of the aluminum foil after immersion in the release agent solution was measured after immersing the aluminum foil in the release agent solution, washing the aluminum foil with water, then immersing it in methyl ethyl ketone for 1 minute, taking it out, wiping off the surface layer with Nippon Paper Crecia paper wiper, and air-drying it at room temperature for 15 minutes.

[0123] Those with a weight residual ratio of the aluminum foil of 99% or more were rated as "A", those with a ratio of 97% or more and less than 99% were rated as "B", those with a ratio of 95% or more and less than 97% were rated as "C", and those with a ratio of less than 95% were rated as "F" to evaluate the elution property (effect of reducing the elution amount). The results are shown in Table 1. The peelability was A and the elution property was B.

[0124] [Example 2] The release agent solution was the same as in Example 1. Next, using a Thomson-type half-cut blade (high-speed steel, flat type, blade thickness 0.7 mm, blade angle 30 degrees), parallel cuts were provided at intervals of 2 mm on the entire surface of the 100 mm × 100 mm evaluation aluminum foil laminate so as not to cut the aluminum foil. This was done on both sides of the aluminum foil laminate. Next, it was shredded into 12 mm × 12 mm rectangles to obtain crushed pieces. Further, in the same manner as in Example 1, the immersion process was carried out, and the peelability and elution property were evaluated. These results are shown in Table 1. The peelability was A and the elution property was B.

[0125] [Example 3] The release agent solution was the same as in Example 1. Next, using a CO2 laser (400 W, wavelength 10.2 μm), parallel cuts were made at 5-mm intervals without cutting the aluminum foil, as shown in Fig. 6(a), over the entire surface of a 100-mm × 100-mm aluminum foil laminate for evaluation. This was done on both sides of the aluminum foil laminate. Next, it was cut into 50-mm × 50-mm rectangles to obtain crushed pieces. Further, in the same manner as in Example 1, the immersion step was carried out, and the peelability and elution properties were evaluated. The results are shown in Table 1. The peelability was A, and the elution property was B.

[0126] [Example 4] The release agent solution was the same as in Example 1. Next, using a commercially available cutter knife, cuts penetrating the aluminum foil laminate were made in a dashed line pattern at 5-mm intervals as shown in Fig. 6(b) over the entire surface of a 100-mm × 100-mm aluminum foil laminate for evaluation, with the interval between each dashed line being 2.5 mm in one direction. Next, it was cut into 20-mm × 20-mm rectangles to obtain crushed pieces. Further, in the same manner as in Example 1, the immersion step was carried out, and the peelability and elution properties were evaluated. The results are shown in Table 1. The peelability was B, and the elution property was B.

[0127] [Example 5] The release agent solution was the same as in Example 1. Next, using an iron needle, through-holes with a diameter of approximately 500 μm were provided at about 25 per cm 2 over the entire surface of a 100-mm × 100-mm aluminum foil laminate for evaluation. Next, it was cut into 20-mm × 20-mm rectangles to obtain crushed pieces. Further, in the same manner as in Example 1, the immersion step was carried out, and the peelability and elution properties were evaluated. The results are shown in Table 1. The peelability was C, and the elution property was B.

[0128] [Example 6] Into a 100 mL glass bottle, 17.39 g of nitric acid (manufactured by Fujifilm Wako Pure Chemical Corporation, reagent special grade, 69% by mass), 1.2 g of ammonium formate (manufactured by Fujifilm Wako Pure Chemical Corporation, Wako special grade), 3 g of diammonium hydrogen citrate (manufactured by Fujifilm Wako Pure Chemical Corporation, reagent special grade), and 78.4 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 release agent solution. Next, in the same manner as in Example 1, as a recess-providing step, parallel cuts were made at intervals of 5 mm using a Thomson-type half-cut blade on the entire surfaces of both sides of the aluminum foil laminate for evaluation to provide recesses, and as a crushing step, it was shredded into a 20 mm × 20 mm rectangle to obtain crushed pieces. Further, in the same manner as in Example 1, the immersion step was carried out, and the releasability and elution property were evaluated. These results are shown in Table 1. The releasability was A and the elution property was C.

[0129] [Example 7] Into a 100 mL glass bottle, 2.90 g of nitric acid (manufactured by Fujifilm Wako Pure Chemical Corporation, reagent special grade, 69% by mass), 75 g of ammonium formate (manufactured by Fujifilm Wako Pure Chemical Corporation, Wako special grade), and 22.1 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 release agent solution. Next, in the same manner as in Example 1, as a recess-providing step, parallel cuts were made at intervals of 5 mm using a Thomson-type half-cut blade on the entire surfaces of both sides of the aluminum foil laminate for evaluation to provide recesses, and as a crushing step, it was shredded into a 20 mm × 20 mm rectangle to obtain crushed pieces. Further, in the same manner as in Example 1, the immersion step was carried out, and the releasability and elution property were evaluated. These results are shown in Table 1. The releasability was C and the elution property was A.

[0130] [Example 8] Into a 100 mL glass bottle, 13.16 g of formic acid (manufactured by Asahi Chemical Industry Co., Ltd., reagent special grade, 76% by mass), 45 g of ammonium formate (manufactured by Fujifilm Wako Pure Chemical Corporation, Wako special grade), and 41.8 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 release agent solution. Next, in the same manner as in Example 1, as the recessed portion forming step, parallel cuts were made at intervals of 5 mm on the entire surfaces of both sides of the aluminum foil laminate for evaluation using a Thomson type half-cut blade to form recesses, and as the crushing step, it was shredded into a 20 mm × 20 mm rectangle to obtain crushed pieces. Further, in the same manner as in Example 1, the dipping step was carried out, and the peelability and elution properties were evaluated. These results are shown in Table 1. The peelability was B, and the elution property was B.

[0131] [Example 9] Into a 100 mL glass bottle, 2.90 g of nitric acid (manufactured by Fujifilm Wako Pure Chemical Corporation, reagent special grade, 69% by mass), 1.2 g of ammonium formate (manufactured by Fujifilm Wako Pure Chemical Corporation, Wako special grade), and 95.9 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 release agent solution. Next, in the same manner as in Example 1, as the recessed portion forming step, parallel cuts were made at intervals of 5 mm on the entire surfaces of both sides of the aluminum foil laminate for evaluation using a Thomson type half-cut blade to form recesses, and as the crushing step, it was shredded into a 20 mm × 20 mm rectangle to obtain crushed pieces. Further, in the same manner as in Example 1, the dipping step was carried out, and the peelability and elution properties were evaluated. These results are shown in Table 1. The peelability was C, and the elution property was C.

[0132] [Example 10] In a 100 mL glass bottle, 7.81 g of sulfuric acid (manufactured by Fujifilm Wako Pure Chemical Corporation, reagent special grade, 64% by mass), 5 g of ammonium formate (manufactured by Fujifilm Wako Pure Chemical Corporation, Wako special grade), and 87.2 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 release agent solution. Then, in the same manner as in Example 1, as a recess-providing step, parallel cuts were made at intervals of 5 mm using a Thomson-type half-cut blade on the entire surfaces of both sides of the aluminum foil laminate for evaluation to provide recesses, and as a crushing step, it was shredded into 20 mm × 20 mm rectangles to obtain crushed pieces. Further, in the same manner as in Example 1, the immersion step was carried out, and the peelability and elution property were evaluated. These results are shown in Table 1. The peelability was B and the elution property was C.

[0133] [Example 11] In a 100 mL glass bottle, 17.65 g of phosphoric acid (manufactured by Fujifilm Wako Pure Chemical Corporation, reagent special grade, 85% by mass), 5 g of ammonium formate (manufactured by Fujifilm Wako Pure Chemical Corporation, Wako special grade), and 77.4 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 release agent solution. Then, in the same manner as in Example 1, as a recess-providing step, parallel cuts were made at intervals of 5 mm using a Thomson-type half-cut blade on the entire surfaces of both sides of the aluminum foil laminate for evaluation to provide recesses, and as a crushing step, it was shredded into 20 mm × 20 mm rectangles to obtain crushed pieces. Further, in the same manner as in Example 1, the immersion step was carried out, and the peelability and elution property were evaluated. These results are shown in Table 1. The peelability was C and the elution property was A.

[0134] [Example 12] In a 100 mL glass bottle, 30.1 g of acetic acid (manufactured by Fujifilm Wako Pure Chemical Corporation, reagent special grade, 99.7% by mass), 5 g of ammonium formate (manufactured by Fujifilm Wako Pure Chemical Corporation, Wako special grade), and 64.9 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 release agent solution. Next, in the same manner as in Example 1, as a recess-providing step, parallel cuts were made at intervals of 5 mm using a Thomson-type half-cut blade on the entire surfaces of both sides of the aluminum foil laminate for evaluation to provide recesses, and as a crushing step, it was shredded into a 20 mm × 20 mm rectangle to obtain crushed pieces. Further, in the same manner as in Example 1, the immersion step was carried out, and the peelability and elution properties were evaluated. These results are shown in Table 1. The peelability was C, and the elution property was A.

[0135] [Example 13] In a 100 mL glass bottle, 6.58 g of formic acid (manufactured by Asahi Chemical Industry Co., Ltd., reagent special grade, 76% by mass), 5 g of ammonium formate (manufactured by Fujifilm Wako Pure Chemical Corporation, Wako special grade), and 88.4 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 release agent solution. Next, in the same manner as in Example 1, as a recess-providing step, parallel cuts were made at intervals of 5 mm using a Thomson-type half-cut blade on the entire surfaces of both sides of the aluminum foil laminate for evaluation to provide recesses, and as a crushing step, it was shredded into a 20 mm × 20 mm rectangle to obtain crushed pieces. Further, in the same manner as in Example 1, the immersion step was carried out, and the peelability and elution properties were evaluated. These results are shown in Table 1. The peelability was B, and the elution property was B.

[0136] [Example 14] In a 100 mL glass bottle, 7.25 g of nitric acid (manufactured by Fujifilm Wako Pure Chemical Corporation, reagent special grade, 69% by mass), 5 g of ammonium acetate (manufactured by Fujifilm Wako Pure Chemical Corporation, Wako special grade), and 87.8 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 release agent solution. Next, in the same manner as in Example 1, as a recess forming step, parallel cuts were made at intervals of 5 mm using a Thomson type half-cut blade on the entire surfaces of both sides of the aluminum foil laminate for evaluation to form recesses, and as a crushing step, it was shredded into a 20 mm × 20 mm rectangle to obtain crushed pieces. Further, in the same manner as in Example 1, the immersion step was carried out, and the peelability and elution property were evaluated. These results are shown in Table 1. The peelability was B and the elution property was B.

[0137] [Example 15] In a 100 mL glass bottle, 7.25 g of nitric acid (manufactured by Fujifilm Wako Pure Chemical Corporation, reagent special grade, 69% by mass), 2.5 g of ammonium acetate (manufactured by Fujifilm Wako Pure Chemical Corporation, Wako special grade), 2.5 g of ammonium formate (manufactured by Fujifilm Wako Pure Chemical Corporation, Wako special grade), and 87.8 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 release agent solution. Next, in the same manner as in Example 1, as a recess forming step, parallel cuts were made at intervals of 5 mm using a Thomson type half-cut blade on the entire surfaces of both sides of the aluminum foil laminate for evaluation to form recesses, and as a crushing step, it was shredded into a 20 mm × 20 mm rectangle to obtain crushed pieces. Further, in the same manner as in Example 1, the immersion step was carried out, and the peelability and elution property were evaluated. These results are shown in Table 1. The peelability was A and the elution property was B.

[0138] [Example 16] Into a 100 mL glass bottle, 2.9 g of nitric acid (manufactured by Fujifilm Wako Pure Chemical Corporation, reagent special grade, 69% by mass), 5.26 g of formic acid (manufactured by Asahi Chemical Industry Co., Ltd., reagent special grade, 76% by mass), 5 g of ammonium formate (manufactured by Fujifilm Wako Pure Chemical Corporation, Wako special grade), and 86.8 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 release agent solution. Then, in the same manner as in Example 1, as a recess-providing step, parallel cuts were made at intervals of 5 mm on the entire surfaces of both sides of the aluminum foil laminate for evaluation using a Thomson-type half-cut blade to provide recesses, and as a crushing step, it was shredded into a 20 mm × 20 mm rectangle to obtain crushed pieces. Further, in the same manner as in Example 1, the dipping step was carried out, and the peelability and elution properties were evaluated. These results are shown in Table 1. The peelability was A and the elution property was B.

[0139] [Example 17] Into a 100 mL glass bottle, 7.25 g of nitric acid (manufactured by Fujifilm Wako Pure Chemical Corporation, reagent special grade, 69% by mass), 5 g of ammonium formate (manufactured by Fujifilm Wako Pure Chemical Corporation, Wako special grade), 3 g of ethyl acetate (manufactured by Fujifilm Wako Pure Chemical Corporation, reagent special grade), and 84.8 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 release agent solution. Then, in the same manner as in Example 1, as a recess-providing step, parallel cuts were made at intervals of 5 mm on the entire surfaces of both sides of the aluminum foil laminate for evaluation using a Thomson-type half-cut blade to provide recesses, and as a crushing step, it was shredded into a 20 mm × 20 mm rectangle to obtain crushed pieces. Further, in the same manner as in Example 1, the dipping step was carried out, and the peelability and elution properties were evaluated. These results are shown in Table 1. The peelability was A and the elution property was C.

[0140] [Example 18] Into a 100 mL glass bottle, 7.25 g of nitric acid (manufactured by Fujifilm Wako Pure Chemical Corporation, reagent special grade, 69% by mass), 5 g of ammonium formate (manufactured by Fujifilm Wako Pure Chemical Corporation, Wako special grade), 3 g of methyl ethyl ketone (manufactured by Fujifilm Wako Pure Chemical Corporation, reagent special grade), and 84.8 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 release agent solution. Next, in the same manner as in Example 1, as a recessed portion forming step, parallel cuts were made at intervals of 5 mm on the entire surfaces of both sides of the aluminum foil laminate for evaluation using a Thomson type half-cut blade to form recesses, and as a crushing step, the laminate was shredded into 20 mm × 20 mm rectangles to obtain crushed pieces. Further, in the same manner as in Example 1, the dipping step was carried out, and the peelability and elution property were evaluated. The results are shown in Table 1. The peelability was A and the elution property was B.

[0141] [Comparative Example 1] Into a 100 mL glass bottle, 42.5 g of acetic acid (manufactured by Fujifilm Wako Pure Chemical Corporation, reagent special grade, 99.7% by mass), 3.5 g of sodium acetate (manufactured by Fujifilm Wako Pure Chemical Corporation, reagent special grade), 1.1 g of disodium hydrogen phosphate (manufactured by Fujifilm Wako Pure Chemical Corporation, reagent special grade), and 52.9 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 release agent solution. Next, in the same manner as in Example 1, as a recessed portion forming step, parallel cuts were made at intervals of 5 mm on the entire surfaces of both sides of the aluminum foil laminate for evaluation using a Thomson type half-cut blade to form recesses, and as a crushing step, the laminate was shredded into 20 mm × 20 mm rectangles to obtain crushed pieces. Further, in the same manner as in Example 1, the dipping step was carried out, and the peelability and elution property were evaluated. The results are shown in Table 1. The peelability was F and the elution property was A.

[0142] [Comparative Example 2] In a 100 mL glass bottle, 17.39 g of nitric acid (manufactured by Fuji Film Wako Pure Chemical Industries, Ltd., reagent special grade, 69% by mass) and 82.6 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 release agent solution. Next, in the same manner as in Example 1, as the recessed portion forming step, parallel cuts were made at intervals of 5 mm using a Thomson-type half-cut blade on the entire surfaces of both sides of the aluminum foil laminate for evaluation to form recesses, and as the crushing step, it was shredded into a 20 mm × 20 mm rectangle to obtain crushed pieces. Further, in the same manner as in Example 1, the immersion step was carried out, and the peelability and elution property were evaluated. These results are shown in Table 1. The peelability was A, and the elution property was F.

[0143] [Comparative Example 3] In a 100 mL glass bottle, 15.79 g of formic acid (manufactured by Asahi Chemical Industry Co., Ltd., reagent special grade, 76% by mass) and 84.2 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 release agent solution. Next, in the same manner as in Example 1, as the recessed portion forming step, parallel cuts were made at intervals of 5 mm using a Thomson-type half-cut blade on the entire surfaces of both sides of the aluminum foil laminate for evaluation to form recesses, and as the crushing step, it was shredded into a 20 mm × 20 mm rectangle to obtain crushed pieces. Further, in the same manner as in Example 1, the immersion step was carried out, and the peelability and elution property were evaluated. These results are shown in Table 1. The peelability was A, and the elution property was F.

[0144] [Comparative Example 4] In a 100 mL glass bottle, 18.75 g of sulfuric acid (manufactured by Fuji Film Wako Pure Chemical Industries, Ltd., reagent, 64% by mass) and 81.3 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 release agent solution. Next, in the same manner as in Example 1, as the recessed portion forming step, parallel cuts were made at intervals of 5 mm using a Thomson-type half-cut blade on the entire surfaces of both sides of the aluminum foil laminate for evaluation to form recesses, and as the crushing step, it was shredded into a 20 mm × 20 mm rectangle to obtain crushed pieces. Further, in the same manner as in Example 1, the immersion step was carried out, and the peelability and elution property were evaluated. These results are shown in Table 1. The peelability was F, and the elution property was F.

[0145] [Comparative Example 5] To a 100 mL glass bottle, 14.12 g of phosphoric acid (manufactured by Fujifilm Wako Pure Chemical Corporation, reagent special grade, 85% by mass) and 85.9 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 release agent solution. Then, in the same manner as in Example 1, as the recess-providing step, parallel cuts were made at intervals of 5 mm using a Thomson-type half-cut blade on the entire surfaces of both sides of the aluminum foil laminate for evaluation to provide recesses, and as the crushing step, it was shredded into a 20 mm × 20 mm rectangle to obtain crushed pieces. Further, in the same manner as in Example 1, the immersion step was carried out, and the peelability and elution properties were evaluated. These results are shown in Table 1. The peelability was F, and the elution property was F.

[0146] [Comparative Example 6] To a 100 mL glass bottle, 5 g of ammonium formate (manufactured by Fujifilm Wako Pure Chemical Corporation, Wako special grade) and 95.0 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 release agent solution. Then, in the same manner as in Example 1, as the recess-providing step, parallel cuts were made at intervals of 5 mm using a Thomson-type half-cut blade on the entire surfaces of both sides of the aluminum foil laminate for evaluation to provide recesses, and as the crushing step, it was shredded into a 20 mm × 20 mm rectangle to obtain crushed pieces. Further, in the same manner as in Example 1, the immersion step was carried out, and the peelability and elution properties were evaluated. These results are shown in Table 1. The peelability was F, and the elution property was A.

[0147] [Comparative Example 7] To a 100 mL glass bottle, 17.39 g of nitric acid (manufactured by Fujifilm Wako Pure Chemical Corporation, reagent special grade, 69% by mass), 1 g of ammonium formate (manufactured by Fujifilm Wako Pure Chemical Corporation, Wako special grade), and 81.6 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 release agent solution. Then, in the same manner as in Example 1, as the recess-providing step, parallel cuts were made at intervals of 5 mm using a Thomson-type half-cut blade on the entire surfaces of both sides of the aluminum foil laminate for evaluation to provide recesses, and as the crushing step, it was shredded into a 20 mm × 20 mm rectangle to obtain crushed pieces. Further, in the same manner as in Example 1, the immersion step was carried out, and the peelability and elution properties were evaluated. These results are shown in Table 1. The peelability was A, and the elution property was F.

[0148] [Comparative Example 8] In a 100 mL glass bottle, 1.45 g of nitric acid (manufactured by Fujifilm Wako Pure Chemical Corporation, reagent special grade, 69% by mass), 75 g of ammonium formate (manufactured by Fujifilm Wako Pure Chemical Corporation, Wako special grade), and 23.6 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 release agent solution. Next, in the same manner as in Example 1, as the indentation step, parallel cuts were made at intervals of 5 mm using a Thomson-type half-cut blade on the entire surfaces of both sides of the aluminum foil laminate for evaluation, and recesses were provided. As the crushing step, the laminate was shredded into 20 mm × 20 mm rectangles to obtain crushed pieces. Further, in the same manner as in Example 1, the immersion step was carried out, and the peelability and elution properties were evaluated. The results are shown in Table 1. The peelability was F and the elution property was A.

[0149] [Comparative Example 9] The procedure was the same as in Example 1 except that the indentation step was not carried out. Further, in the same manner as in Example 1, the immersion step was carried out, and the peelability and elution properties were evaluated. The results are shown in Table 1. The peelability was F and the elution property was B.

[0150]

Table 1

[0151] The separation method of the present invention was carried out by adjusting a release agent solution as a release agent solution corresponding to release agent solution B in Examples 19 to 43 below. A release agent solution having a composition different from both release agent solution A and release agent solution B, which is similar to release agent solution B, was adjusted or carried out by a method different from the separation method of the present invention in Comparative Examples 10 to 18 below, respectively.

[0152] [Example 19] <Preparation of Release Agent Solution, and Implementation of Indentation Step and Crushing Step> Into a 100 mL glass bottle, 14.49 g of nitric acid (manufactured by Fujifilm Wako Pure Chemical Corporation, reagent special grade, 69% by mass), 30 g of citric acid (manufactured by Fujifilm Wako Pure Chemical Corporation, Wako special grade), and 55.51 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 release agent solution. Next, in the same manner as in Example 1, as a recessed portion forming step, parallel cuts were made at intervals of 5 mm using a Thomson type half-cut blade on the entire surfaces of both sides of the aluminum foil laminate for evaluation, and recesses were provided. As a crushing step, it was shredded into 20 mm × 20 mm rectangles to obtain crushed pieces. Further, in the same manner as in Example 1, the immersion step was carried out, and the peelability and elution property were evaluated. These results are shown in Table 2. The peelability was A, and the elution property was A.

[0153] [Example 20] Into a 100 mL glass bottle, 14.49 g of nitric acid (manufactured by Fujifilm Wako Pure Chemical Corporation, reagent special grade, 69% by mass), 30 g of citric acid (manufactured by Fujifilm Wako Pure Chemical Corporation, Wako special grade), and 55.51 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 release agent solution. Next, parallel cuts were made at intervals of 2 mm using a Thomson type half-cut blade (high speed steel, flat type, blade thickness 0.7 mm, blade angle 30 degrees) on the entire surface of the 100 mm × 100 mm aluminum foil laminate for evaluation so as not to cut the aluminum foil. This was done on both sides of the aluminum foil laminate. Next, it was shredded into 12 mm × 12 mm rectangles to obtain crushed pieces. Further, in the same manner as in Example 1, the immersion step was carried out, and the peelability and elution property were evaluated. These results are shown in Table 2. The peelability was A, and the elution property was A.

[0154] [Example 21] Into a 100 mL glass bottle, 14.49 g of nitric acid (manufactured by Fujifilm Wako Pure Chemical Corporation, reagent special grade, 69% by mass), 30 g of citric acid (manufactured by Fujifilm Wako Pure Chemical Corporation, Wako special grade), and 55.51 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 release agent solution. Next, using a CO2 laser (400 W, wavelength 10.2 μm), parallel cuts were made at 5 mm intervals without cutting the aluminum foil as shown in Fig. 6(a) on the entire surface of a 100 mm × 100 mm aluminum foil laminate for evaluation. This was done on both sides of the aluminum foil laminate. Next, it was cut into rectangles of 50 mm × 50 mm to obtain crushed pieces. Further, in the same manner as in Example 1, the immersion process was carried out, and the peelability and elution properties were evaluated. The results are shown in Table 2. The peelability was A and the elution property was A.

[0155] [Example 22] Into a 100 mL glass bottle, 14.49 g of nitric acid (manufactured by Fujifilm Wako Pure Chemical Corporation, reagent special grade, 69% by mass), 30 g of citric acid (manufactured by Fujifilm Wako Pure Chemical Corporation, Wako special grade), and 55.51 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 release agent solution. Next, using a commercially available cutter knife, cuts penetrating the aluminum foil laminate were made in a dashed line pattern at 5 mm intervals as shown in Fig. 6(b) on the entire surface of a 100 mm × 100 mm aluminum foil laminate for evaluation, with the interval between each dashed line being 2.5 mm in one direction. Next, it was cut into rectangles of 20 mm × 20 mm to obtain crushed pieces. Further, in the same manner as in Example 1, the immersion process was carried out, and the peelability and elution properties were evaluated. The results are shown in Table 2. The peelability was B and the elution property was A.

[0156] [Example 23] Into a 100 mL glass bottle, 14.49 g of nitric acid (manufactured by Fujifilm Wako Pure Chemical Corporation, reagent special grade, 69% by mass), 30 g of citric acid (manufactured by Fujifilm Wako Pure Chemical Corporation, Wako special grade), and 55.51 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 release agent solution. Next, using an iron needle, about 25 pieces / cm 2, a through-hole with a diameter of about 500 μm was provided. Next, it was shredded into 20 mm × 20 mm rectangles to obtain crushed pieces. Further, in the same manner as in Example 1, the immersion step was carried out, and the peelability and elution property were evaluated. The results are shown in Table 2. The peelability was C and the elution property was A.

[0157] [Example 24] Into a 100 mL glass bottle, 14.49 g of nitric acid (manufactured by Fujifilm Wako Pure Chemical Corporation, special grade reagent, 69% by mass), 30 g of diammonium hydrogen citrate (manufactured by Fujifilm Wako Pure Chemical Corporation, special grade reagent), and 55.51 g of purified water (manufactured by AS ONE Corporation, ASSWS - 20) were added, and stirred at 40 °C for 30 minutes to prepare a release agent solution. Next, in the same manner as in Example 19, as the recess - forming step, parallel cuts were made at 5 - mm intervals using a Thomson - type half - cut blade on the entire surfaces of both sides of the aluminum foil laminate for evaluation to form recesses, and as the crushing step, it was shredded into 20 mm × 20 mm rectangles to obtain crushed pieces. Further, in the same manner as in Example 1, the immersion step was carried out, and the peelability and elution property were evaluated. The results are shown in Table 2. The peelability was A and the elution property was A. The peelability was A and the elution property was A.

[0158] [Example 25] Into a 100 mL glass bottle, 13.16 g of formic acid (manufactured by Asahi Chemical Industry Co., Ltd., special grade reagent, 76% by mass), 30 g of citric acid (manufactured by Fujifilm Wako Pure Chemical Corporation, Wako special grade), and 56.84 g of purified water (manufactured by AS ONE Corporation, ASSWS - 20) were added, and stirred at 40 °C for 30 minutes to prepare a release agent solution. Next, in the same manner as in Example 19, as the recess - forming step, parallel cuts were made at 5 - mm intervals using a Thomson - type half - cut blade on the entire surfaces of both sides of the aluminum foil laminate for evaluation to form recesses, and as the crushing step, it was shredded into 20 mm × 20 mm rectangles to obtain crushed pieces. Further, in the same manner as in Example 1, the immersion step was carried out, and the peelability and elution property were evaluated. The results are shown in Table 2. The peelability was A and the elution property was A.

[0159] [Example 26] In a 100 mL glass bottle, 8.70 g of nitric acid (manufactured by Fujifilm Wako Pure Chemical Corporation, reagent special grade, 69% by mass), 3 g of citric acid (manufactured by Fujifilm Wako Pure Chemical Corporation, Wako special grade), and 88.30 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 release agent solution. Then, in the same manner as in Example 19, as a recess - forming step, parallel cuts were made at 5 - mm intervals using a Thomson - type half - cut blade on the entire surfaces of both sides of the aluminum foil laminate for evaluation to form recesses, and as a crushing step, it was shredded into 20 mm × 20 mm rectangles to obtain crushed pieces. Further, in the same manner as in Example 1, the immersion step was carried out, and the peelability and elution property were evaluated. These results are shown in Table 2. The peelability was A, and the elution property was B.

[0160] [Example 27] In a 100 mL glass bottle, 4.35 g of nitric acid (manufactured by Fujifilm Wako Pure Chemical Corporation, reagent special grade, 69% by mass), 0.1 g of citric acid (manufactured by Fujifilm Wako Pure Chemical Corporation, Wako special grade), and 95.55 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 release agent solution. Then, in the same manner as in Example 19, as a recess - forming step, parallel cuts were made at 5 - mm intervals using a Thomson - type half - cut blade on the entire surfaces of both sides of the aluminum foil laminate for evaluation to form recesses, and as a crushing step, it was shredded into 20 mm × 20 mm rectangles to obtain crushed pieces. Further, in the same manner as in Example 1, the immersion step was carried out, and the peelability and elution property were evaluated. These results are shown in Table 2. The peelability was B, and the elution property was B.

[0161] [Example 28] In a 100 mL glass bottle, 3.95 g of formic acid (manufactured by Asahi Chemical Industry Co., Ltd., reagent special grade, 76% by mass), 0.1 g of citric acid (manufactured by Fujifilm Wako Pure Chemical Corporation, Wako special grade), and 95.95 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 release agent solution. Next, in the same manner as in Example 19, as a recess-providing step, parallel cuts were made at intervals of 5 mm on the entire surfaces of both sides of the aluminum foil laminate for evaluation using a Thomson-type half-cut blade to provide recesses, and as a crushing step, the laminate was shredded into 20 mm × 20 mm rectangles to obtain crushed pieces. Further, in the same manner as in Example 1, the immersion step was carried out, and the peelability and elution properties were evaluated. The results are shown in Table 2. The peelability was B and the elution property was A.

[0162] [Example 29] In a 100 mL glass bottle, 2.90 g of nitric acid (manufactured by Fujifilm Wako Pure Chemical Corporation, reagent special grade, 69% by mass), 35 g of citric acid (manufactured by Fujifilm Wako Pure Chemical Corporation, Wako special grade), and 62.10 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 release agent solution. Next, in the same manner as in Example 19, as a recess-providing step, parallel cuts were made at intervals of 5 mm on the entire surfaces of both sides of the aluminum foil laminate for evaluation using a Thomson-type half-cut blade to provide recesses, and as a crushing step, the laminate was shredded into 20 mm × 20 mm rectangles to obtain crushed pieces. Further, in the same manner as in Example 1, the immersion step was carried out, and the peelability and elution properties were evaluated. The results are shown in Table 2. The peelability was B and the elution property was A.

[0163] [Example 30] In a 100 mL glass bottle, 50.72 g of nitric acid (manufactured by Fujifilm Wako Pure Chemical Corporation, reagent special grade, 69% by mass), 15 g of citric acid (manufactured by Fujifilm Wako Pure Chemical Corporation, Wako special grade), 10 g of ammonium formate (manufactured by Fujifilm Wako Pure Chemical Corporation, Wako special grade), and 34.28 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 release agent solution. Then, in the same manner as in Example 19, as a recess-forming step, parallel cuts were made at intervals of 5 mm using a Thomson-type half-cut blade on the entire surfaces of both sides of the aluminum foil laminate for evaluation to form recesses, and as a crushing step, the laminate was cut into 20 mm × 20 mm rectangles to obtain crushed pieces. Further, in the same manner as in Example 1, the immersion step was carried out, and the peelability and elution properties were evaluated. The results are shown in Table 2. The peelability was A, and the elution property was A.

[0164] [Example 31] In a 100 mL glass bottle, 46.05 g of formic acid (manufactured by Asahi Chemical Industry Co., Ltd., reagent special grade, 76% by mass), 15 g of citric acid (manufactured by Fujifilm Wako Pure Chemical Corporation, Wako special grade), and 38.95 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 release agent solution. Then, in the same manner as in Example 19, as a recess-forming step, parallel cuts were made at intervals of 5 mm using a Thomson-type half-cut blade on the entire surfaces of both sides of the aluminum foil laminate for evaluation to form recesses, and as a crushing step, the laminate was cut into 20 mm × 20 mm rectangles to obtain crushed pieces. Further, in the same manner as in Example 1, the immersion step was carried out, and the peelability and elution properties were evaluated. The results are shown in Table 2. The peelability was A, and the elution property was B.

[0165] [Example 32] Into a 100 mL glass bottle, 2.90 g of nitric acid (manufactured by Fujifilm Wako Pure Chemical Corporation, reagent special grade, 69% by mass), 0.3 g of citric acid (manufactured by Fujifilm Wako Pure Chemical Corporation, Wako special grade), and 96.80 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 release agent solution. Then, in the same manner as in Example 19, as a recess-providing step, parallel cuts were made at intervals of 5 mm using a Thomson-type half-cut blade on the entire surfaces of both sides of the aluminum foil laminate for evaluation to provide recesses, and as a crushing step, it was shredded into a 20 mm × 20 mm rectangle to obtain crushed pieces. Further, in the same manner as in Example 1, the immersion step was carried out, and the peelability and elution properties were evaluated. These results are shown in Table 2. The peelability was B, and the elution property was B.

[0166] [Example 33] Into a 100 mL glass bottle, 2.90 g of nitric acid (manufactured by Fujifilm Wako Pure Chemical Corporation, reagent special grade, 69% by mass), 5.26 g of formic acid (manufactured by Asahi Chemical Industry Co., Ltd., reagent special grade, 76% by mass), 1 g of citric acid (manufactured by Fujifilm Wako Pure Chemical Corporation, Wako special grade), and 90.84 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 release agent solution. Then, in the same manner as in Example 19, as a recess-providing step, parallel cuts were made at intervals of 5 mm using a Thomson-type half-cut blade on the entire surfaces of both sides of the aluminum foil laminate for evaluation to provide recesses, and as a crushing step, it was shredded into a 20 mm × 20 mm rectangle to obtain crushed pieces. Further, in the same manner as in Example 1, the immersion step was carried out, and the peelability and elution properties were evaluated. These results are shown in Table 2. The peelability was A, and the elution property was A.

[0167] [Example 34] Into a 100 mL glass bottle, 8.70 g of nitric acid (manufactured by Fujifilm Wako Pure Chemical Corporation, reagent special grade, 69% by mass), 3 g of L(+)-tartaric acid (manufactured by Fujifilm Wako Pure Chemical Corporation, reagent special grade), and 88.30 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 release agent solution. Then, in the same manner as in Example 19, as a recess-providing step, parallel cuts were made at intervals of 5 mm using a Thomson-type half-cut blade on the entire surfaces of both sides of the aluminum foil laminate for evaluation to provide recesses, and as a crushing step, it was shredded into a 20 mm × 20 mm rectangle to obtain crushed pieces. Further, in the same manner as in Example 1, the dipping step was carried out, and the peelability and elution properties were evaluated. The results are shown in Table 2. The peelability was A and the elution property was B.

[0168] [Example 35] Into a 100 mL glass bottle, 8.70 g of nitric acid (manufactured by Fujifilm Wako Pure Chemical Corporation, reagent special grade, 69% by mass), 3.4 g of lactic acid (manufactured by Fujifilm Wako Pure Chemical Corporation, Wako special grade, 88.5%), and 87.91 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 release agent solution. Then, in the same manner as in Example 19, as a recess-providing step, parallel cuts were made at intervals of 5 mm using a Thomson-type half-cut blade on the entire surfaces of both sides of the aluminum foil laminate for evaluation to provide recesses, and as a crushing step, it was shredded into a 20 mm × 20 mm rectangle to obtain crushed pieces. Further, in the same manner as in Example 1, the dipping step was carried out, and the peelability and elution properties were evaluated. The results are shown in Table 2. The peelability was A and the elution property was B.

[0169] [Example 36] In a 100 mL glass bottle, 8.70 g of nitric acid (manufactured by Fujifilm Wako Pure Chemical Corporation, reagent special grade, 69% by mass), 3.0 g of malic acid (manufactured by Fujifilm Wako Pure Chemical Corporation, reagent special grade), and 88.30 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 release agent solution. Then, in the same manner as in Example 19, as a recess - forming step, parallel cuts were made at intervals of 5 mm using a Thomson - type half - cut blade on the entire surfaces of both sides of the aluminum foil laminate for evaluation to form recesses, and as a crushing step, the laminate was shredded into 20 mm × 20 mm rectangles to obtain crushed pieces. Further, in the same manner as in Example 1, the immersion step was carried out, and the peelability and elution properties were evaluated. The results are shown in Table 2. The peelability was A and the elution property was B.

[0170] [Example 37] In a 100 mL glass bottle, 8.70 g of nitric acid (manufactured by Fujifilm Wako Pure Chemical Corporation, reagent special grade, 69% by mass), 3.0 g of maleic acid (manufactured by Fujifilm Wako Pure Chemical Corporation, Wako special grade), and 88.30 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 release agent solution. Then, in the same manner as in Example 19, as a recess - forming step, parallel cuts were made at intervals of 5 mm using a Thomson - type half - cut blade on the entire surfaces of both sides of the aluminum foil laminate for evaluation to form recesses, and as a crushing step, the laminate was shredded into 20 mm × 20 mm rectangles to obtain crushed pieces. Further, in the same manner as in Example 1, the immersion step was carried out, and the peelability and elution properties were evaluated. The results are shown in Table 2. The peelability was A and the elution property was B.

[0171] [Example 38] Into a 100 mL glass bottle, 8.70 g of nitric acid (manufactured by Fujifilm Wako Pure Chemical Corporation, reagent special grade, 69% by mass), 3.0 g of phthalic anhydride (manufactured by Fujifilm Wako Pure Chemical Corporation, Wako special grade), and 88.30 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 release agent solution. Then, in the same manner as in Example 19, as a recess-providing step, parallel cuts were made at intervals of 5 mm using a Thomson-type half-cut blade on the entire surfaces of both sides of the aluminum foil laminate for evaluation to provide recesses, and as a crushing step, it was shredded into a 20 mm × 20 mm rectangle to obtain crushed pieces. Further, in the same manner as in Example 1, the immersion step was carried out, and the peelability and elution properties were evaluated. The results are shown in Table 2. The peelability was A and the elution property was B.

[0172] [Example 39] Into a 100 mL glass bottle, 8.70 g of nitric acid (manufactured by Fujifilm Wako Pure Chemical Corporation, reagent special grade, 69% by mass), 3.0 g of trisodium citrate (manufactured by Fujifilm Wako Pure Chemical Corporation, food additive), and 88.30 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 release agent solution. Then, in the same manner as in Example 19, as a recess-providing step, parallel cuts were made at intervals of 5 mm using a Thomson-type half-cut blade on the entire surfaces of both sides of the aluminum foil laminate for evaluation to provide recesses, and as a crushing step, it was shredded into a 20 mm × 20 mm rectangle to obtain crushed pieces. Further, in the same manner as in Example 1, the immersion step was carried out, and the peelability and elution properties were evaluated. The results are shown in Table 2. The peelability was A and the elution property was B.

[0173] [Example 40] Into a 100 mL glass bottle, 8.70 g of nitric acid (manufactured by Fujifilm Wako Pure Chemical Corporation, reagent special grade, 69% by mass), 1.5 g of citric acid (manufactured by Fujifilm Wako Pure Chemical Corporation, Wako special grade), 1.5 g of trisodium citrate (manufactured by Fujifilm Wako Pure Chemical Corporation, food additive), and 88.30 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 release agent solution. Then, in the same manner as in Example 19, as a recess-providing step, parallel cuts were made at intervals of 5 mm using a Thomson-type half-cut blade on the entire surfaces of both sides of the aluminum foil laminate for evaluation to provide recesses, and as a crushing step, the laminate was shredded into 20 mm × 20 mm rectangles to obtain crushed pieces. Further, in the same manner as in Example 1, the immersion step was carried out, and the releasability and elution property were evaluated. The results are shown in Table 2. The releasability was A, and the elution property was B.

[0174] [Example 41] Into a 100 mL glass bottle, 5.80 g of nitric acid (manufactured by Fujifilm Wako Pure Chemical Corporation, reagent special grade, 69% by mass), 1 g of citric acid (manufactured by Fujifilm Wako Pure Chemical Corporation, Wako special grade), 4 g of acetic acid (manufactured by Fujifilm Wako Pure Chemical Corporation, reagent special grade), and 89.20 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 release agent solution. Then, in the same manner as in Example 19, as a recess-providing step, parallel cuts were made at intervals of 5 mm using a Thomson-type half-cut blade on the entire surfaces of both sides of the aluminum foil laminate for evaluation to provide recesses, and as a crushing step, the laminate was shredded into 20 mm × 20 mm rectangles to obtain crushed pieces. Further, in the same manner as in Example 1, the immersion step was carried out, and the releasability and elution property were evaluated. The results are shown in Table 2. The releasability was A, and the elution property was A.

[0175] [Example 42] Into a 100 mL glass bottle, 2.90 g of nitric acid (manufactured by Fujifilm Wako Pure Chemical Corporation, reagent special grade, 69% by mass), 35 g of citric acid (manufactured by Fujifilm Wako Pure Chemical Corporation, Wako special grade), 10 g of butyl acetate (manufactured by Fujifilm Wako Pure Chemical Corporation, reagent special grade), and 52.10 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 release agent solution. Next, in the same manner as in Example 19, as a recess-forming step, parallel cuts were made at intervals of 5 mm using a Thomson-type half-cut blade on the entire surfaces of both sides of the aluminum foil laminate for evaluation to form recesses, and as a crushing step, the laminate was shredded into 20 mm × 20 mm rectangles to obtain crushed pieces. Further, in the same manner as in Example 1, the dipping step was carried out, and the releasability and elution property were evaluated. The results are shown in Table 2. The releasability was B and the elution property was A.

[0176] [Example 43] Into a 100 mL glass bottle, 2.90 g of nitric acid (manufactured by Fujifilm Wako Pure Chemical Corporation, reagent special grade, 69% by mass), 35 g of citric acid (manufactured by Fujifilm Wako Pure Chemical Corporation, Wako special grade), 10 g of methyl ethyl ketone (manufactured by Fujifilm Wako Pure Chemical Corporation, reagent special grade), and 52.10 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 release agent solution. Next, in the same manner as in Example 19, as a recess-forming step, parallel cuts were made at intervals of 5 mm using a Thomson-type half-cut blade on the entire surfaces of both sides of the aluminum foil laminate for evaluation to form recesses, and as a crushing step, the laminate was shredded into 20 mm × 20 mm rectangles to obtain crushed pieces. Further, in the same manner as in Example 1, the dipping step was carried out, and the releasability and elution property were evaluated. The results are shown in Table 2. The releasability was B and the elution property was A.

[0177] [Comparative Example 10] In a 100 mL glass bottle, 42.5 g of acetic acid (manufactured by Fujifilm Wako Pure Chemical Corporation, reagent grade, 99.7% by mass), 3.5 g of sodium acetate (manufactured by Fujifilm Wako Pure Chemical Corporation, reagent grade), 1.1 g of disodium hydrogen phosphate (manufactured by Fujifilm Wako Pure Chemical Corporation, reagent grade), and 52.9 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 release agent solution. Next, in the same manner as in Example 19, as the recess-providing step, parallel cuts were made at intervals of 5 mm using a Thomson-type half-cut blade on the entire surfaces of both sides of the aluminum foil laminate for evaluation to provide recesses, and as the crushing step, the laminate was shredded into 20 mm × 20 mm rectangles to obtain crushed pieces. Further, in the same manner as in Example 1, the immersion step was carried out, and the peelability and elution properties were evaluated. The results are shown in Table 2. The peelability was F and the elution property was A.

[0178] [Comparative Example 11] In a 100 mL glass bottle, 14.49 g of nitric acid (manufactured by Fujifilm Wako Pure Chemical Corporation, reagent grade, 69% by mass) and 85.51 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 release agent solution. Next, in the same manner as in Example 19, as the recess-providing step, parallel cuts were made at intervals of 5 mm using a Thomson-type half-cut blade on the entire surfaces of both sides of the aluminum foil laminate for evaluation to provide recesses, and as the crushing step, the laminate was shredded into 20 mm × 20 mm rectangles to obtain crushed pieces. Further, in the same manner as in Example 1, the immersion step was carried out, and the peelability and elution properties were evaluated. The results are shown in Table 2. The peelability was A and the elution property was F.

[0179] [Comparative Example 12] To a 100 mL glass bottle, 13.16 g of formic acid (manufactured by Asahi Chemical Industry Co., Ltd., reagent special grade, 76% by mass) and 86.84 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 release agent solution. Next, in the same manner as in Example 19, as a recess-providing step, parallel cuts were made at intervals of 5 mm using a Thomson-type half-cut blade on the entire surfaces of both sides of the aluminum foil laminate for evaluation to provide recesses, and as a crushing step, the laminate was shredded into 20 mm × 20 mm rectangles to obtain crushed pieces. Further, in the same manner as in Example 1, the immersion step was carried out, and the peelability and elution property were evaluated. The results are shown in Table 2. The peelability was A and the elution property was F.

[0180] [Comparative Example 13] To a 100 mL glass bottle, 27.78 g of hydrochloric acid (manufactured by Fujifilm Wako Pure Chemical Corporation, reagent special grade, 36% by mass) and 72.22 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 release agent solution. Next, in the same manner as in Example 19, as a recess-providing step, parallel cuts were made at intervals of 5 mm using a Thomson-type half-cut blade on the entire surfaces of both sides of the aluminum foil laminate for evaluation to provide recesses, and as a crushing step, the laminate was shredded into 20 mm × 20 mm rectangles to obtain crushed pieces. Further, in the same manner as in Example 1, the immersion step was carried out, and the peelability and elution property were evaluated. The results are shown in Table 2. The peelability was F and the elution property was F.

[0181] [Comparative Example 14] To a 100 mL glass bottle, 33.33 g of hydrogen peroxide (manufactured by Fujifilm Wako Pure Chemical Corporation, reagent special grade, 30% by mass) and 67.67 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 release agent solution. Next, in the same manner as in Example 19, as a recess-providing step, parallel cuts were made at intervals of 5 mm using a Thomson-type half-cut blade on the entire surfaces of both sides of the aluminum foil laminate for evaluation to provide recesses, and as a crushing step, the laminate was shredded into 20 mm × 20 mm rectangles to obtain crushed pieces. Further, in the same manner as in Example 1, the immersion step was carried out, and the peelability and elution property were evaluated. The results are shown in Table 2. The peelability was F and the elution property was A.

[0182] [Comparative Example 15] In a 100 mL glass bottle, 35 g of citric acid (manufactured by Fujifilm Wako Pure Chemical Corporation, Wako Special Grade, 99.5% by mass) and 65.0 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 release agent solution. Then, in the same manner as in Example 19, as the recess-providing step, parallel cuts were made at intervals of 5 mm using a Thomson-type half-cut blade on the entire surfaces of both sides of the aluminum foil laminate for evaluation to provide recesses, and as the crushing step, it was shredded into 20 mm × 20 mm rectangles to obtain crushed pieces. Further, in the same manner as in Example 1, the immersion step was carried out, and the peelability and elution property were evaluated. The results are shown in Table 2. The peelability was F and the elution property was A.

[0183] [Comparative Example 16] In a 100 mL glass bottle, 1.45 g of nitric acid (manufactured by Fujifilm Wako Pure Chemical Corporation, Reagent Special Grade, 69% by mass), 35 g of citric acid (manufactured by Fujifilm Wako Pure Chemical Corporation, Wako Special Grade), and 63.55 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 release agent solution. Then, in the same manner as in Example 19, as the recess-providing step, parallel cuts were made at intervals of 5 mm using a Thomson-type half-cut blade on the entire surfaces of both sides of the aluminum foil laminate for evaluation to provide recesses, and as the crushing step, it was shredded into 20 mm × 20 mm rectangles to obtain crushed pieces. Further, in the same manner as in Example 1, the immersion step was carried out, and the peelability and elution property were evaluated. The results are shown in Table 2. The peelability was F and the elution property was A.

[0184] [Comparative Example 17] To a 100 mL glass bottle, 5.80 g of nitric acid (manufactured by Fuji Film Wako Pure Chemical Industries, Ltd., reagent special grade, 69% by mass), 0.1 g of citric acid (manufactured by Fuji Film Wako Pure Chemical Industries, Ltd., Wako special grade), and 94.10 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 release agent solution. Next, in the same manner as in Example 19, as the recessed portion forming step, parallel cuts were made at intervals of 5 mm using a Thomson type half-cut blade on the entire surfaces of both sides of the aluminum foil laminate for evaluation, and recesses were provided. As the crushing step, the laminate was cut into 20 mm × 20 mm rectangles to obtain crushed pieces. Further, in the same manner as in Example 1, the immersion step was carried out, and the peelability and elution properties were evaluated. The results are shown in Table 2. The peelability was A and the elution property was F.

[0185] [Comparative Example 18] Except that the recessed portion forming step was not carried out, the same procedure as in Example 19 was followed. Further, in the same manner as in Example 1, the immersion step was carried out, and the peelability and elution properties were evaluated. The results are shown in Table 2. The peelability was F and the elution property was A.

[0186] [Table 2]

[0187] From the comparison of each of the examples and comparative examples in Table 1 and Table 2, it can be seen that in any of the embodiments, providing recesses in the crushed pieces promotes the peeling between the aluminum foil and the resin layer. From Examples 1 to 18 in Table 1, it can be seen that using an ammonium salt composed of at least one of ammonium formate and ammonium acetate further suppresses the elution of aluminum. Also, as in Examples 19 to 43 in Table 2, it can be seen that using one or more third acids selected from the group consisting of polyvalent carboxylic acids, hydroxy acids, polyvalent carboxylates, and hydroxycarboxylates also further suppresses the elution of aluminum.

[0188] As shown in the above results, (Release Agent Solution A) contains an ammonium salt consisting of at least one of ammonium formate and ammonium acetate in an amount of 1.2% by mass or more and 75% by mass or less, one or more first acids selected from the group consisting of nitric acid, sulfuric acid, phosphoric acid, formic acid, and acetic acid in an amount of 2% by mass or more and 30% by mass or less, and water in an amount of 23% by mass or more and 96.8% by mass or less. The total of the ammonium salt, the first acid, and the water is 100% by mass or less in the release agent solution A, and the content ratio obtained by dividing the content (% by mass) of the ammonium salt by the content (% by mass) of the first acid is 0.1 or more and 37.5 or less. (Release Agent Solution B) contains a second acid consisting of at least one of nitric acid and formic acid in an amount of 2% by mass or more and 35% by mass or less, one or more third acids selected from the group consisting of polycarboxylic acids, hydroxy acids, polycarboxylate salts, and hydroxycarboxylate salts in an amount of 0.1% by mass or more and 35% by mass or less, and water in an amount of 40% by mass or more and 97.7% by mass or less. The total of the second acid, the third acid, and the water is 100% by mass or less in the release agent solution B, and the content ratio obtained by dividing the content (% by mass) of the second acid by the content (% by mass) of the third acid is 0.057 or more and 30 or less. Any of these release agent solutions can be suitably used separately for the aluminum foil and the resin layer. Further, since these release agent solutions can easily penetrate from the recess provided in the recess forming step and spread over the interface between the aluminum foil and the resin layer, the aluminum foil and the resin layer can be efficiently separated in a short time.

[0189] The above-described embodiments are examples of the present invention, and the present invention is not limited to these examples. Well-known techniques, conventional techniques, or known techniques may be combined with or partially replaced in these examples. Further, modified inventions that can be easily conceived by those skilled in the art are also included in the present invention.

Explanation of Reference Numerals

[0190] 10 Fragment 20 Aluminum Foil 30 Resin Layer 40 Hole-shaped Recess 50, 55 Notch-shaped Recess 60 Adhesive Layer 70 and 75 Aluminum Foil Laminates 80 Rolls 90 Protrusions 100 Rotary Blades

Claims

1. A method for separating an aluminum foil and a resin layer from an aluminum foil laminate having an aluminum foil and a resin layer, A recessing step of providing a recess in the aluminum foil laminate; A crushing step of crushing the aluminum foil laminate to obtain crushed pieces; and an immersion step of immersing the crushed pieces in a stripping agent solution, The stripper solution comprises: (Stripper solution A) containing 1.2 mass % or more and 75 mass % or less of an ammonium salt consisting of at least one of ammonium formate and ammonium acetate, 2 mass % or more and 30 mass % or less of one or more first acids selected from the group consisting of nitric acid, sulfuric acid, phosphoric acid, formic acid and acetic acid, and 23 mass % or more and 96.8 mass % or less of water, wherein the total of the ammonium salt, the first acid and the water is 100 mass % or less in the stripper solution A, and a content ratio obtained by dividing the content (mass %) of the ammonium salt by the content (mass %) of the first acid is 0.1 or more and 37.5 or less, (Stripper solution B) containing 2% by mass or more and 35% by mass or less of a second acid consisting of at least one of nitric acid and formic acid, 0.1% by mass or more and 35% by mass or less of one or more third acids selected from the group consisting of polycarboxylic acids, hydroxy acids, polycarboxylic acid salts and hydroxy acid salts, and 40% by mass or more and 97.7% by mass or less of water, wherein the total of the second acid, the third acid and the water is 100% by mass or less in the stripper solution B, and a content ratio obtained by dividing the content (mass%) of the second acid by the content (mass%) of the third acid is 0.057 or more and 30 or less, 13. A separation method, comprising:

2. 2. The method according to claim 1, wherein the recessing step is a step of sending the aluminum foil laminate to the crushing step using at least one pair of rolls, and forming recesses in the aluminum foil laminate at the same time as sending it out by a convex portion provided on at least one surface of the roll.

3. The sorting method according to claim 1 , wherein the recessing step is a step of forming a recess in the aluminum foil laminate using a needle having a pointed tip.

4. The sorting method according to claim 1, wherein the recessing step is a step of forming a recess by at least one of a through hole and a slit penetrating the aluminum foil laminate.

5. The sorting method according to claim 1, wherein the crushing step is a step of crushing the aluminum foil laminate into rectangles each having a side length of 1 mm or more and 50 mm or less.

6. 2. The method according to claim 1, wherein the stripper solution A contains, as the balance, 10 mass% or less of one or more acids selected from the group consisting of polycarboxylic acids, hydroxy acids, polycarboxylic acid salts, and hydroxy acid salts.

7. 2. The method according to claim 1, wherein the stripper solution A contains 50 mass% or less of one or more organic solvents selected from the group consisting of ketones, ethers, alkylbenzenes, dioxolanes, cycloalkanes and carboxylates.

8. 2. The method according to claim 1, wherein the third acid in the stripper solution B is one or more selected from the group consisting of citric acid, tartaric acid, lactic acid, malic acid, maleic acid, phthalic anhydride, sodium citrate, and diammonium hydrogen citrate.

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