JP-2026075797-A - Separation solution for aluminum foil laminates and method for separating and recovering aluminum foil laminates using the same

Abstract

[Problem] To provide a separation solution for aluminum foil laminates that has sufficient ability to separate the aluminum foil laminate into resin and aluminum foil, while reducing the elution of aluminum foil into the separation solution and reducing impurities when the recovered aluminum foil is melted and cast, and a method for separating and recovering aluminum foil laminates using the same. [Solution] According to the present invention, a separation solution for aluminum foil laminates is provided, which contains an ammonium salt consisting of at least one of ammonium formate and ammonium acetate, one or more acids selected from the group consisting of nitric acid, sulfuric acid, phosphoric acid, formic acid, and acetic acid, and water, characterized in that the content ratio obtained by dividing the content of the ammonium salt (mass%) in the separation solution by the content of the acid (mass%) in the separation solution is 0.1 or more and 40.0 or less. [Selection Diagram] None

Inventors

• 東 直樹

Assignees

• 東洋アルミニウム株式会社

Dates

Publication Date

20260511

Application Date

20241023

Claims (5)

1. An ammonium salt consisting of at least one of ammonium formate and ammonium acetate, One or more acids selected from the group consisting of nitric acid, sulfuric acid, phosphoric acid, formic acid, and acetic acid, In a separation solution for aluminum foil laminates containing water, The separation solution is characterized in that the content ratio obtained by dividing the content (mass%) of the ammonium salt in the separation solution by the content (mass%) of the acid in the separation solution is 0.1 or more and 40.0 or less.
2. The content of the ammonium salt in the separation solution is 1.2% by mass or more and 75% by mass or less. The separation solution for aluminum foil laminates according to claim 1, characterized in that the acid content in the separation solution is 2% by mass or more and 30% by mass or less.
3. The separation solution for aluminum foil laminates according to claim 1, characterized in that the separation solution contains, as a remainder, 10% by 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.
4. The separation solution for aluminum foil laminates according to claim 3, characterized by containing 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 in the separation solution.
5. A process for preparing an aluminum foil laminate containing aluminum foil and resin, A process of crushing and/or cutting a laminate containing aluminum foil and resin using a crusher and/or cutter to obtain crushed and/or pulverized material, A method for separating and recovering an aluminum foil laminate, comprising the steps of: immersing the crushed material and/or the cut material in the separation solution described in any one of claims 1 to 4; and separating the aluminum foil and resin by allowing it to stand or stir at a temperature of 15°C to 99°C for a period of 1 second to 24 hours.

Description

This invention relates to a separation solution for aluminum foil laminates, in which a resin is laminated on at least one of the aluminum foils, for separating the aluminum foil from the resin, and to a method for separating and recovering the aluminum foil laminate using the same. Traditionally, laminates in which resin is laminated on at least one side of aluminum foil (hereinafter referred to as "aluminum foil laminates") have been widely used in applications requiring barrier properties, such as packaging materials for food and pharmaceuticals, to protect contents from external environmental factors like oxygen, moisture, and ultraviolet light. Furthermore, due to their excellent electrical properties and processability, aluminum foil laminates are also widely used in industrial applications such as electronic components. Furthermore, since the resin used in the lamination of aluminum foil laminates must meet various requirements such as heat sealing properties, strength, puncture resistance, and aesthetic appeal, many types of resins are used, including epoxy resins, olefin resins, nitrocellulose resins, vinyl chloride-vinyl acetate copolymer resins, and polyethylene resins. However, with the recent rise in awareness of SDGs and the global environment, there is a growing demand for high recyclability in resin-containing laminates. The diverse combinations of materials and components, including the aforementioned resins, have been hindering the recycling of these laminates. In particular, in the case of aluminum foil laminates containing aluminum foil, the difficulty in easily separating the aluminum foil from the resin has hindered recycling. Therefore, in order to utilize the properties of aluminum foil while also achieving high recyclability, methods are being considered to improve the separation properties between the aluminum foil and the laminated resin layer. For example, Japanese Patent Publication No. 47-034572 (Patent Document 1) discloses a method for separating the resin layer from the aluminum foil by dissolving at least a portion of the aluminum foil. Furthermore, Japanese Patent Publication No. 2021-526091 (Patent Document 2) discloses a method for separating the metal layer from the resin using a separation fluid (separation solution) containing a mixture of water, a carboxylic acid, a carboxylate salt, and a passivating agent. Japanese Patent Application Publication No. 47-034572Special Publication No. 2021-526091 The following describes in detail a separation solution for aluminum foil laminates according to one embodiment of the present invention and a method for separating and recovering aluminum foil laminates using the same. Note that the present invention is not limited to the embodiments shown below, and various modifications are possible without departing from the technical spirit of the invention. <Separation solution for aluminum foil laminates> The separation solution for aluminum foil laminates of the present invention is characterized in that it contains an ammonium salt consisting of at least one of ammonium formate and ammonium acetate, one or more acids selected from the group consisting of nitric acid, sulfuric acid, phosphoric acid, formic acid, and acetic acid, and water, wherein the content ratio obtained by dividing the content of the ammonium salt (mass%) in the separation solution by the content of the acid (mass%) in the separation solution is 0.1 or more and 40.0 or less. Furthermore, the method for separating an aluminum foil laminate into resin and aluminum foil according to the present invention is characterized by comprising the steps of: crushing, pulverizing, and/or cutting an aluminum foil laminate of any size so that the maximum length in a planar plane is between 1 mm and 50 mm to obtain crushed material, pulverized material, and/or cut material; and immersing the crushed material, pulverized material, and/or cut material in the above-mentioned separation solution for aluminum foil laminates, and separating them into aluminum foil and resin by standing or stirring at a temperature of 15°C to 99°C for a period of 1 second to 24 hours. The surface of aluminum foil is typically rich in functional groups such as carboxyl groups, carbonyl groups, and hydroxyl groups. These polar groups bond with the polar groups on the resin surface, creating a strong bond and forming an aluminum foil laminate. In this invention, one or more acids selected from the group consisting of nitric acid, sulfuric acid, phosphoric acid, formic acid, and acetic acid function to break the bond between the functional groups of the resin and the aluminum foil, thereby separating the aluminum foil from the resin. The components of the separation solution for aluminum foil laminates in this invention will be described in detail below. <Acid> The acid used in this invention is an acid consisting of at least one of nitric acid, sulfuric acid, phosphoric acid, formic acid, and acetic acid.