KR-20260062976-A - Resin recovery method

KR20260062976AKR 20260062976 AKR20260062976 AKR 20260062976AKR-20260062976-A

Abstract

The resin recovery method of the present invention is a method for recovering resin from a composite comprising a layer (A) comprising a non-hydrolyzable resin (a1) and a layer (B) comprising a hydrolyzable resin (b1), comprising a process (1) in which the composite is contacted with a subcritical fluid to decompose and/or separate the layer (A) and the layer (B) to obtain a solid resin (A) comprising a non-hydrolyzable resin (a2) and a solid resin (B) comprising a hydrolyzable resin (b2), wherein the non-hydrolyzable resin (a1) and the non-hydrolyzable resin (a2) are identical or differ only in molecular weight distribution, and the hydrolyzable resin (b1) and the hydrolyzable resin (b2) are identical or differ only in molecular weight distribution.

Inventors

다카마, 아키라
야마시타, 준
기미즈카, 유타
나리타, 가즈타카

Assignees

유비이 가부시키가이샤

Dates

Publication Date: 20260507
Application Date: 20240906
Priority Date: 20230908

Claims (13)

A method for recovering resin from a composite comprising a layer (A) containing a non-hydrolyzable resin (a1) and a layer (B) containing a hydrolyzable resin (b1), The method comprises a process (1) of contacting the above composite with a subcritical fluid to decompose and/or separate layers (A) and (B) to obtain a solid resin (A) made of a non-hydrolyzable resin (a2) and a solid resin (B) made of a hydrolyzable resin (b2). The above non-hydrolyzable resin (a1) and the above non-hydrolyzable resin (a2) are identical or differ only in molecular weight distribution, and The above hydrolyzable resin (b1) and the above hydrolyzable resin (b2) are identical or differ only in molecular weight distribution. Resin recovery method.
A resin recovery method according to claim 1, further comprising a recovery process (2) for separating and recovering the solid resin (A) and the solid resin (B) obtained in the process (1) through a filter.
A resin recovery method according to claim 1, further comprising a recovery process (2) for recovering the solid resin (A) and the solid resin (B) obtained in the process (1) by separating them based on the difference in specific gravity between the solid resin (A) and the solid resin (B).
A resin recovery method according to claim 1, wherein the number average molecular weight of the hydrolyzable resin (b1) is Mn1 and the number average molecular weight of the hydrolyzable resin (b2) is Mn2, and the ratio of Mn2 to Mn1 (Mn2/Mn1) is 0.15 or higher and Mn2 is 2300 or higher.
A resin recovery method according to claim 1, wherein in the process (1), the time for contacting the composite and the subcritical fluid is 1 to 60 minutes.
A resin recovery method according to claim 1, wherein the non-hydrolyzable resins (a1) and (a2) are polyolefin resins.
A resin recovery method according to claim 1, wherein the hydrolyzable resins (b1) and (b2) are polyamide resins or polyester resins.
A resin recovery method according to claim 1, wherein the composite is waste plastic.
A method for recovering resin from a molded body containing a hydrolyzable resin (b1), The method includes a process of contacting the above-mentioned molded body with a subcritical fluid to obtain a solid resin (B) made of a hydrolyzable resin (b2), and The above hydrolyzable resin (b1) and the above hydrolyzable resin (b2) are the same or have different molecular weight distributions. Resin recovery method.
A material recycled product comprising the above-mentioned non-hydrolyzable resin (a2) recovered by the resin recovery method described in any one of claims 1 to 8 in the raw material.
A material recycled product comprising the hydrolyzable resin (b2) recovered by the resin recovery method described in any one of claims 1 to 9 in the raw material.
A method for manufacturing a material recycled product, wherein the non-hydrolyzable resin (a2) recovered by the resin recovery method described in any one of claims 1 to 8 is used as a raw material for material recycling.
A method for manufacturing a recycled material product, wherein the hydrolyzable resin (b2) recovered by the resin recovery method described in any one of claims 1 to 9 is used as a raw material for material recycling.

Description

Resin recovery method The present invention relates to a method for recovering resin from a composite comprising a plurality of resins. Due to the growing interest in environmental issues and the effective use of resources, the reuse of resin products is being demanded. Resin products, such as films used in packaging, are generally composites of multiple resins, such as multilayer films. To reuse these composites, it is necessary to separate and recover the resins from the composite according to the type of resin. In Patent Document 1, a laminate of a polyolefin layer and a layer of foreign matter other than polyolefin selected from water-soluble foreign matter or hydrolyzable foreign matter is treated with water under specific pressure at 200 to 400°C, thereby dissolving only the foreign matter in water and recovering the polyolefin. In Patent Document 2, the organic material other than the polyolefin resin is hydrolyzed and the polyolefin resin is recovered by treating a polyolefin resin film containing an organic material other than the polyolefin resin with water under specific pressure and heating conditions of 200 to 350°C. In Patent Document 3, a solid composite material containing two or more organic polymer compounds is hydrolyzed using supercritical water as a solvent, and after separating the organic liquid and the organic solid, the organic solid is recovered, and the separated organic liquid is separated and recovered by material by boiling point separation. In Patent Document 4, a resin layer of a hydrolyzable polymer and a resin layer of a non-hydrolyzable polymer are decomposed and separated by a hydrothermal reaction under specific conditions, and the hydrolyzable polymer is hydrolyzed and separated and recovered as a monomer, while the non-hydrolyzable polymer is separated and recovered while maintaining its molecular weight. FIG. 1 is an example of a device for performing the resin recovery method of the present invention. A first aspect of the present invention is a resin recovery method from a composite comprising a layer (A) comprising a non-hydrolyzable resin (a1) and a layer (B) comprising a hydrolyzable resin (b1), comprising a process (1) in which the composite is contacted with a subcritical fluid to decompose and/or separate the layer (A) and the layer (B) to obtain a solid resin (A) composed of a non-hydrolyzable resin (a2) and a solid resin (B) composed of a hydrolyzable resin (b2), wherein the non-hydrolyzable resin (a1) and the non-hydrolyzable resin (a2) are identical or differ only in molecular weight distribution, and the hydrolyzable resin (b1) and the hydrolyzable resin (b2) are identical or differ only in molecular weight distribution. In this specification, the term "solid resin" refers to a resin that is solid at 25°C and 1 atm. <Process (1)> Process (1) contacts a composite comprising a layer (A) containing a non-hydrolyzable resin (a1) and a layer (B) containing a hydrolyzable resin (b1) with a subcritical fluid. In process (1), layers (A) and (B) are decomposed and/or separated, and a solid resin (A) consisting of a non-hydrolyzable resin (a2) and a solid resin (B) consisting of a hydrolyzable resin (b2) are obtained. Here, "constitutes" means that it does not include components not contained in the complex. Preferably, it means that it does not include anything other than trace impurities, and more preferably, it means that it "contains only." A composite refers to a structure in which layers comprising two or more types of resins or resin compositions are bonded together either directly or through an adhesive, and examples include laminates and bonded bodies. The composite comprises layers (A) and (B). Layers (A) and (B) may be adjacent or bonded, or they may not be adjacent. The composite may include layers other than layers (A) and (B) and other compositions. For example, the composite may optionally have an inorganic layer in addition to layers (A) and (B). In layer (A), it is preferable that the non-hydrolyzable resin (a1) is the main component, and in layer (B), it is preferable that the hydrolyzable resin (b1) is the main component. "In layer (A), the non-hydrolyzable resin (a1) is the main component" means that the non-hydrolyzable resin (a1) is included in the largest mass among the total components of the composition constituting layer (A), and in 100 mass% of the composition constituting layer (A), the non-hydrolyzable resin (a1) is included in 50 mass% or more, preferably 70 mass% or more, more preferably 95 mass% or more, and also includes an embodiment in which 100 mass%, that is, layer (A), contains only the non-hydrolyzable resin (a1). The same applies to "In layer (B), the hydrolyzable resin (b1) is the main component". A non-hydrolyzable resin is a resin in which the bonds within the resin are not hydrolyzed or are difficult to hydrolyze. A non-hydrolyzable thermoplastic resin is preferred, and examples include polyethylene resins such as low-den