CN-122029021-A - Method for recycling laminated body

Abstract

The present invention provides a recycling method capable of easily and effectively recycling both a resin from a functional layer and a resin from a base material from a laminate having the functional layer and the base material, and suppressing burden on the environment. The recycling method of the laminate according to the embodiment of the present invention is a recycling method of recovering a resin from a functional layer and a resin from a base material from a laminate having the functional layer and the base material, wherein the laminate is brought into contact with an alkali compound in a solid state.

Inventors

• YAMADA YOSUKE
• KOTANI TOMOHISA
• OJI KATSUNARI
• YAMAMOTO AKIYOSHI
• Sichuan Bamboo Yujia

Assignees

• 日东电工株式会社

Dates

Publication Date

20260512

Application Date

20241015

Priority Date

20231016

Claims (14)

1. 1. A recycling method of a laminate, which is a recycling method of recovering a resin from a functional layer and a resin from a base material from a laminate having the functional layer and the base material, The method comprises the following steps: The laminate is brought into contact with an alkali compound in a solid state.
2. 2. The method for recycling a laminate according to claim 1, wherein, After the contacting, an organic solvent is added to a mixture comprising the laminate and the base compound.
3. 3. The method for recycling a laminate according to claim 2, wherein, The organic solvent is alcohol.
4. 4. The method for recycling a laminate according to claim 1, wherein, Mixing a mixture comprising the laminate and the alkali compound.
5. 5. The method for recycling a laminate according to claim 4, wherein, The kneading is performed by a kneading mechanism that imparts a shearing force to a mixture including the laminate and the alkali compound.
6. 6. The method for recycling a laminate according to claim 5, wherein, The kneading mechanism comprises a stirring blade and a reactor, wherein the ratio B1/D1 of the diameter B1 (mm) of the stirring blade to the diameter R1 (mm) of the reactor is 0.5 or more.
7. 7. The method for recycling a laminate according to claim 4, wherein, At least a part of the kneading is performed under reduced pressure.
8. 8. The recycling method of a laminated body according to claim 1, comprising: and a separation step of separating the resin from the functional layer from the resin from the base material.
9. 9. The method for recycling a laminate according to claim 8, wherein, In the separation step, the filter is used to separate the functional layer, and 90% by weight or more of the resin from the functional layer passes through the filter, but 90% by weight or more of the resin from the base material does not pass through the filter.
10. 10. The method for recycling a laminate according to claim 8, wherein, The separation step is a separation utilizing solubility in a liquid in which 90% by weight or more of the resin from the functional layer is dissolved and 90% by weight or more of the resin from the base material is not dissolved.
11. 11. The method for recycling a laminate according to claim 1, wherein, The functional layer is formed of an acrylic adhesive, and the resin from the functional layer is a hydrophilic polymer.
12. 12. The method for recycling a laminate according to claim 4, wherein, During the kneading, an alcohol is produced.
13. 13. The recycling method of a laminated body according to claim 12, comprising: An alcohol recovery step of recovering the alcohol produced during the kneading.
14. 14. The method for recycling a laminate according to claim 13, wherein, The alcohol recovery step is to recover the alcohol produced during the kneading under reduced pressure.

Description

Method for recycling laminated body Technical Field The present invention relates to a method for recycling a laminate. Background Adhesive tapes have been used in a large number for attaching labels and the like to articles and packaging materials, packaging materials, use in manufacturing processes of electronic components and optical components, masking applications, and the like. In particular, in recent years, the use of the adhesive tape in the manufacturing process of electronic components and optical components has increased, and a large amount of waste of the adhesive tape has been generated in the manufacturing site and the like. The waste of the adhesive tape is usually burned for disposal or brought to a waste disposal plant for disposal. However, such disposal is not preferable from the viewpoint of reducing environmental load and further from the viewpoint of recycling resources. Therefore, it is necessary to reduce the waste of the pressure-sensitive adhesive tape as much as possible in the above-described waste treatment and reuse the resources. As a method for reducing the disposal of such an adhesive tape, recycling of the raw material of the adhesive tape can be considered. If the recycling technology of the raw materials of the adhesive tape can be established, suppression of CO 2 emissions associated with, for example, exploitation of fossil resources is concerned, and a remarkable effect can be expected for solving the problem of climate change. As a material of the pressure-sensitive adhesive tape, a pressure-sensitive adhesive and a base material are typically exemplified. Typically, an adhesive tape is obtained by dissolving an additive such as a polymer (sometimes referred to as a base polymer) and a crosslinking agent, which corresponds to the purpose, in a solvent to prepare an adhesive composition, applying the adhesive composition to a substrate, and if necessary, heating/drying the substrate to cause a crosslinking reaction to proceed, thereby forming an adhesive on the substrate (for example, patent document 1). As a technique related to recycling of an adhesive tape, a method of removing a functional layer such as an adhesive layer from a base film having the functional layer has been reported (patent document 2). This method is reported to be a method of bringing a substrate film wound into a roll into contact with an alkaline treatment liquid in an alkaline treatment tank in a long form, and is characterized in that the substrate film is brought into contact with the alkaline treatment liquid in the alkaline treatment tank in a long form, not in a crushed form. However, this technique is not aimed at recycling the functional layer, but at recovering the base film from which the functional layer has been removed. That is, this has not been accomplished as a recycling system capable of recycling and regenerating both the functional layer and the base film. Further, since the alkaline treatment liquid used is an aqueous solution, the effect of removing the functional layer is low for the functional layer having low compatibility with water. As another technique related to recycling of the adhesive tape, a method of cleaning a laminated polyester film having a functional layer on the surface of the polyester film with a treatment liquid containing an alkaline agent and an alcohol, removing the functional layer, and recycling the polyester film from which the functional layer has been removed has been reported (patent document 3). In this method, the treatment liquid contains an organic solvent, so that the compatibility with the treatment liquid is improved even for a functional layer having low compatibility with water. However, there is room for improvement as a recycling technique from the viewpoint of environmental load due to CO 2 discharge from an organic solvent and the like. In addition, this technique is also aimed at recycling the polyester film from which the functional layer has been removed, rather than recycling the functional layer. That is, the present invention has not been completed as a recycling system capable of recycling and regenerating both the functional layer and the polyester film. Prior art literature Patent literature Patent document 1 Japanese patent application laid-open No. 2021-175796 Patent document 2 Japanese patent application laid-open No. 2020-90094 Patent document 3 Japanese patent application laid-open No. 2021-160350 Disclosure of Invention Problems to be solved by the invention The present invention aims to provide a recycling method capable of easily and effectively recycling both a resin from a functional layer and a resin from a base material from a laminate having the functional layer and the base material, and suppressing burden on the environment. Means for solving the problems The present inventors have conducted intensive studies to solve the above problems, and as a result, have focused on physical approaches. Among them, the