Chemical recycling method of mixed waste polymer

Abstract

The present invention relates to a method for regenerating a polymer having a urethane functional group and / or a mixed material having an amide functional group, which is characterized in that: when a polymer is regenerated from a mixed material having a urethane functional group and / or an amide functional group, the urethane functional group and / or the amide functional group can be regenerated; the polymer of the mixed material can be brought into contact with one or more first compounds including one or more aromatic compounds having one or more alkoxy functional groups and one or more second compounds including one or more compounds having one or more alcohol functional groups in sequence or at the same time. Therefore, the polymer with the urethane functional group in the composite polymer is selectively dissolved, filtered and separated, and the separated polymer with the urethane functional group is independently depolymerized.

Description

TECHNICAL FIELD

[0001] The present invention relates to a method of chemically regenerating a mixed material polymer, characterized in that, when a mixed material polymer manufactured by randomly mixing or having a certain composition and structure of polymer compounds having different chemical structures is regenerated, a plurality of conditions in which only a specific polymer is selectively dissolved in the mixed material polymer are set, thereby constructing a series of processes in which only a part or a specific polymer is physically separated, and each polymer is separated, and then the separated polymer is depolymerized. BACKGROUND

[0002] A polymer synthesized using a raw material extracted from petroleum is a material that is inexpensive and has durability, and has the advantage of being easily molded and processed, and thus is used in the production of various products such as synthetic fibers or plastics. Due to the advantages as described above, the consumption of products using the synthetic polymer has rapidly increased in various fields of life over the past several decades. However, when the synthetic polymer waste, which is not properly treated after consumption through an environmentally unfriendly method, is disposed of, various environmental problems are caused, some of which are disposed of in the environment through landfill or the like, and are further decomposed into fine pieces and dispersed in various links of the ecosystem and accumulated in living organisms, and finally can be reabsorbed into the human body through, for example, fine dust, drinking water, and food, thereby directly threatening the health and living environment of humans.

[0003] In order to solve the problems as described above, various researches and efforts aimed at minimizing the accumulation or environmental impact of plastics, including the development of a new plastic material having a short decomposition period in a natural state, from the chemical decomposition of existing petroleum-based plastics to the physical regeneration and reprocessing of plastics, are being actively attempted. However, it is known that a material or physical recycling method in which a polymer material itself is washed and then reused, or in which only a part of the form or properties is changed and then reused, is difficult to manage the physical properties or quality, and thus the use and recycling times are limited. In contrast, a depolymerization method in which a used waste synthetic polymer product is chemically decomposed can produce a monomer corresponding to the raw material before synthesis, and even in the case of repeated recycling, a product of the same or similar quality to the initial material can be produced, and thus is highly focused as a realistic technology for constructing a recycling system of resources.

[0004] Depending on the type of polymer, the decomposition characteristics are different and the types and properties of products generated by decomposition are also different from each other, and thus, in order to recycle polymer products of mixed materials in which two or more types of polymers coexist, it is necessary to first perform a process of classifying them as single materials having uniform polymer structure characteristics. In particular, waste fibers discharged after consumption are generally discharged in the form of a mixture of a plurality of types of fibers or a blended material, and thus, in order to recycle them, it is necessary to perform a pretreatment process such as screening, separation, and impurity removal on each polymer within the waste fibers, and a series of recycling methods in which materials separated at each step can be effectively decomposed or treated.

[0005] In recent years, along with the development of functional fiber materials, the related fiber market has also grown, and in particular, the market for fibers based on polyurethane materials, which are referred to as Spandex, Elastan, and Lycra, has shown explosive growth. The polyurethane materials are also referred to by various names such as Elaspan, Acepora, Creora, INVIYA, ROICA, and Dorlastan depending on the manufacturing companies thereof.

[0006] The fibers of the polyurethane materials not only have excellent stretchability, but also have very excellent biocompatibility, and thus perfectly replace existing rubber materials, and compared to materials composed of a single material, fibers mixed and spun together with other synthetic fibers in order to improve their functionality are more widely used.

[0007] In addition to fibers in which polyurethane is added, fibers in which a plurality of materials are mixed with each other in order to improve their functionality or durability can also be used, and for example, mixed fibers manufactured by various combinations and methods using synthetic polymer materials such as polyester or nylon, or natural polymer materials such as cotton, cellulose, hemp, and wool obtained from vegetable or animal raw materials can be used. In addition to blended yarns in which two or more types of fibers are mixed with each other and spun in the industrial spinning process, very complex and diverse materials or forms such as mixed filament yarns in which fibers having different structures and properties are spun or woven into a single long fiber are manufactured and supplied to the market.

[0008] For the fibers of the mixed material, it is difficult to separate each material in the composition individually by only a simple separation technique or a physical screening technique commonly known, and thus becomes a factor that makes it more difficult to recycle the mixed waste fibers discharged after consumption. Recently, although research activities related to a technique of separating fibers according to the material by using optical or super-resolution optical technology are actively conducted, because the structure of the blended fiber itself is complex and the material and the composition are various, the classification itself can not be easy. In addition, even in the case where the classification is achieved, because the decomposition conditions or the chemical properties of the constituent substances are different from each other, there can be many limitations in recycling the material composed of various materials together.

[0009] As an example, in the case where each polymer is separated from the material composed of, for example, a polymer having an ester functional group such as a polyethylene terephthalate (PET) based plastic material or a polyester fiber, a polymer having a urethane functional group such as a polyurethane, or a polymer having an amide bond such as nylon, and depolymerization is simultaneously performed, because the appropriate depolymerization conditions of each polymer are different, not only the depolymerization efficiency of each polymer can be greatly decreased, but also a complex product in which products of depolymerization of each polymer are mixed, for example, a complex product in which various oligomers are mixed in addition to a product of depolymerization of a polymer having an ester functional group, i.e., bis-hydroxyethyl terephthalate (BHET), and a monomer of a polymer having a urethane functional group, i.e., a polyol, is generated, and a purification process of removing a part thereof or separating only a useful monomer and purifying it to high purity can require high energy consumption, and there can be many limitations in the purification technology itself.

[0010] Japanese Patent Publication No. 2014-058476 relates to a method of manufacturing raw material components of a polymer such as bis-hydroxy terephthalic acid, terephthalic acid, and dimethyl terephthalate at a high yield from polyester waste containing polyurethane as a main component, and claims a scheme of controlling the sum of the concentration of isocyanate groups and the concentration of amino groups to be 1000 ppm or less by a method such as dilution or washing of a mixture after a depolymerization reaction, but does not describe a method of separating or recycling polyurethane itself from the waste material individually.

[0011] Japanese Patent Publication No. 2019-035022 relates to a mixed fiber separation method that makes it possible to cause a first fiber that can contain a resin bonded by a urethane bond to be decomposed and maintain a fiber shape, and only cause a second fiber bonded by a beta-glycosidic bond, such as cotton fiber and hemp fiber, and a third fiber bonded by an amide bond to be decomposed and separated, in which the second fiber and the third fiber containing a beta-glycosidic bond and an amide bond are decomposed, but there is no description of selectively causing only a resin having a urethane bond or a resin having an amide bond to be dissolved and separated, and further decomposing a part of them into a raw material. In the case of directly decomposing without separating the polymer components as described above, the obtained product is in a state of being mixed with a plurality of compounds, and in order to chemically reuse it, efficient separation and purification techniques are required, and thus it is extremely poor in economy, and there can be limitations in the quality of the final raw material.

[0012] In addition, Japanese Patent Publication No. 2011-231279 proposes a method of only swelling, decomposing, dissolving, or peeling off a polyurethane from a mixed material in which a polyurethane layer is combined or fixed together with a base material that is not only composed of a polyurethane, i.e., a polypropylene sheet that cannot be decomposed by depolymerization, so that the base material can be separated without the decomposition product of the polyurethane being left or mixed into the base material. This is a method of reusing the base material with the purpose of removing the polyurethane, and is a method of removing the polyurethane, and proposes a method of decomposing and removing the polyurethane layer from the base material by adding a solution in which a solvent having a boiling point of 150°C or higher is mixed with an alkali metal carbonate or phosphate. The method is only limited to a method of removing the polyurethane from a separable material, i.e., a homopolymer resin that does not decompose when exposed to depolymerization conditions, using the principle that there is a significant difference in reactivity between the respective materials even when the materials are mixed with each other. In other words, the method is only applicable to a case where a mixture can be distinguished only as having reactivity or not having reactivity, and is not applicable to a material in which a blended fiber exists in a state of being spun or mixed together with a polyurethane, a nylon, and a polyester, all of which can simultaneously decompose by depolymerization, or two or more polymers having reactivity.

[0013] In the technology disclosed in the current patent literature, the range of reusable waste polymer materials can be limited, or the quality or performance effect of the product manufactured according to the corresponding technology is not significant, and thus the industrial application value can be low.

[0014] In contrast, the applicant has devised a method for selectively dissolving and extracting polymers with urethane and amide functional groups from polymers composed of ester functional groups, polymers with urethane functional groups, polymers with amide functional groups, and polymers composed of various other functional groups, such as some or all of a mixture of cotton, hemp, rayon, silk, acrylic, polyethylene, and polypropylene polymer materials. This method separates or isolates polymers with different chemical properties. Furthermore, experiments have verified that for polymers with urethane and ester functional groups separated from mixed waste polymers or waste fibers, no additional purification or washing process is required. Each polymer can be directly used as a raw material for depolymerization. Moreover, by applying a convenient and efficient low-temperature depolymerization method that allows for rapid decomposition even at low temperatures, the composition of each polymer can be chemically decomposed, thereby producing high-purity, high-yield recycled raw materials (or monomers), thus ultimately completing this invention. Summary of the Invention Technical issues

[0015] The present invention aims to achieve the reuse of waste polymers in mixed materials that are difficult to achieve using existing known separation or decomposition methods. Its purpose is to provide a composition that can be separated from other polymers by selectively dissolving the polymers with urethane functional groups and / or amide functional groups from a mixture of polymers physically mixed together, or blended materials produced in a fibrous manner, such as woven fabrics or knitted fabrics. This includes: a thermodynamic separation method that selectively separates the polymers with urethane functional groups and / or amide functional groups by adjusting the solubility of each polymer in the dissolved mixture; and a depolymerization method that produces renewable monomers or resynthetic raw materials by chemically decomposing the polymers with urethane functional groups and the polymers with urethane functional groups separated by the process.

[0016] Furthermore, the present invention aims to provide a chemical recycling method for a waste polymer material comprising, using the composition, a polymer material containing at least one of the polymers having urethane functional groups and polymers having amide functional groups; or a polymer material containing at least one of the polymers having urethane functional groups and polymers having amide functional groups, and from a polymer material containing, as part or all, natural and synthetic cellulose-based fibers such as cotton, hemp, and rayon; animal fibers such as silk; synthetic fibers such as acrylic, polyethylene, polypropylene, and polymers having ester functional groups; after selectively dissolving and separating the polymers having urethane functional groups and / or the polymers having amide functional groups from a polymer material containing, as part or all, the polymers that can be depolymerized, and then using the depolymerized polymers as reactants as single components, thereby producing a high-purity depolymerized product by applying a depolymerization reaction to the polymers. Technical solution

[0017] To address the aforementioned problem, the present invention provides a composition for selectively dissolving polymers having urethane functional groups and / or polymers having amide functional groups from a polymer of mixed materials, characterized in that: the polymer of mixed materials is a polymer of mixed materials containing polymers having urethane functional groups and polymers having amide functional groups; or a polymer of mixed materials containing one or more polymers selected from the polymers having urethane functional groups and polymers having amide functional groups, and one or more polymers selected from cotton, linen, rayon, silk, acrylic acid, polyethylene, polypropylene, and polymer materials having ester functional groups as part or all of the constituent components, the composition comprising: a first compound comprising one or more aromatic compounds having one or more alkoxy functional groups; and a second compound comprising one or more compounds having one or more alcohol functional groups.

[0018] As an embodiment of the present invention, the weight ratio of the first compound to the second compound in the composition can be 0.01 to 100.

[0019] Furthermore, the present invention provides a method for selectively dissolving a polymer having urethane functional groups and / or a polymer having amide functional groups from a polymer mixture, characterized in that: as a method for selectively dissolving a polymer having urethane functional groups and / or a polymer having amide functional groups from a polymer mixture, the polymer mixture is a polymer mixture having urethane functional groups and a polymer having amide functional groups; or one or more polymers selected from the polymer having urethane functional groups and the polymer having amide functional groups. A polymer mixture comprising one or more polymers selected from cotton, linen, rayon, silk, acrylic acid, polyethylene, polypropylene, and polymers having ester functional groups as part or all of its constituent components, wherein the polymer mixture is sequentially or simultaneously contacted with one or more first compounds comprising aromatic compounds having one or more alkoxy functional groups and one or more second compounds comprising compounds having one or more alcohol functional groups, thereby selectively dissolving polymers having urethane functional groups and / or polymers having amide functional groups from the polymer mixture.

[0020] As an embodiment of the dissolution method of the present invention, when the polymer of the mixed material does not contain a polymer having an amide functional group, the temperature range for selectively dissolving only the polymer having a urethane functional group can be 100 to 180°C. When both the polymer having a urethane functional group and the polymer having an amide functional group are present in the polymer of the mixed material, the temperature range for dissolving both the polymer having a urethane functional group and the polymer having an amide functional group can be 135°C to 180°C.

[0021] In another embodiment of the dissolution method of the present invention, the sequential contact may be first contact with a first compound, followed by contact with a second compound.

[0022] Furthermore, the mass of the first compound relative to the polymer mass of the mixed material can range from 0.1 to 1000 times, and the weight ratio of the first compound to the second compound can range from 0.01 to 100.

[0023] Furthermore, the present invention provides a polymeric material comprising a polymer having an ethyl carbamate functional group and a polymer having an amide functional group; or a method for regenerating a polymeric material comprising a polymeric material having one or more polymers selected from the polymers having an ethyl carbamate functional group and the polymers having an amide functional group, and a polymeric material having one or more polymers selected from cotton, hemp, rayon, silk, acrylic acid, polyethylene, polypropylene, and polymeric materials having ester functional groups as part or all of its constituent components, characterized in that it comprises: (a) mixing the polymeric material of the mixed material with a first compound comprising one or more aromatic compounds having one or more alkoxy functional groups and an aromatic compound comprising one or more aromatic compounds having one or more alkoxy functional groups. (a) contacting one or more second compounds of the alcohol functional group to selectively dissolve only the polymers having urethane functional groups and / or polymers having amide functional groups in the mixed polymer material; (b) filtering the mixed solution generated after the selective dissolution to separate the polymers having urethane functional groups and / or polymers having amide functional groups from the polymer material of the mixed material with a polymer material composed of polymers having ester functional groups and one or more polymers selected from cotton, hemp, rayon, silk, acrylic acid, polyethylene and polypropylene; and (c) a depolymerization reaction step of depolymerizing the polymers separated in the solid phase.

[0024] As an embodiment of the regeneration method of the present invention, the polymer depolymerized in step (c) may be a polymer having ester functional groups.

[0025] As another embodiment of the regeneration method of the present invention, after step (c), it may further include: (d) separating the polymer with urethane functional groups by adjusting the temperature of the separated mixture containing the polymer with urethane functional groups and the polymer with amide functional groups so that only the polymer with amide functional groups settles; and (e) a depolymerization reaction step of depolymerizing the separated polymer with urethane functional groups.

[0026] As another embodiment of the regeneration method of the present invention, it is characterized in that: after step (c), it may further include a depolymerization reaction step of depolymerizing the separated polymer having urethane functional groups.

[0027] As an embodiment of the regeneration method of the present invention, the depolymerization of the polymer having urethane functional groups in step (c) can be carried out by adding a catalyst for depolymerization of the polymer having urethane functional groups to the filtrate filtered in step (b).

[0028] As another embodiment of the regeneration method of the present invention, the catalyst for depolymerizing the polymer having urethane functional groups may be one or more selected from the group consisting of metal catalysts composed of alkali metal hydroxides, alkaline earth metal hydroxides, alkali metal acetates, alkaline earth metal acetates, alkali metal carbonates, alkali metal bicarbonates, alkaline earth metal carbonates, and alkali metal oxides; and organic compounds of guanidines or amines.

[0029] As another embodiment of the regeneration method of the present invention, the depolymerization of the polymer having urethane functional groups can be carried out in a temperature range of 100 to 180°C.

[0030] As another embodiment of the regeneration method of the present invention, in step (c), the depolymerization of the polymer containing the ester functional group can be carried out by one or more of the following methods: hydrolysis, glycolysis, methanolysis, ethanolysis, and ammonolysis.

[0031] As another embodiment of the regeneration method of the present invention, the feature is that: substances in the polymer separated into a solid phase in step (c) that have not undergone depolymerization can be separated from the reaction products by filtration or centrifugation. The effects of the invention

[0032] This invention provides a convenient and efficient method for separating polymer materials, which can selectively dissolve and extract polymers with urethane functional groups and / or amide functional groups from a mixture of polymers containing one or more polymers selected from natural and synthetic cellulose-based fibers such as cotton, hemp, and rayon; animal fibers such as silk; and synthetic fibers such as acrylic acid, polyethylene, polypropylene, and polymers with ester functional groups. Furthermore, the polymers can be separated separately by adjusting the solubility of the polymers with urethane functional groups and those with amide functional groups.

[0033] The compound used to separate a portion or specific polymer material from waste polymer materials of mixed materials exerts its effect by mixing one or more first compounds containing one or more aromatic compounds having one or more alkoxy functional groups and one or more second compounds containing one or more alcohol functional groups. It can be easily integrated with pretreatment processes for waste polymer materials of mixed materials that utilize only the first compound to remove dyes, pigments, and other hydrophobic organic and inorganic impurities. For example, a method can be provided that removes organic impurities in a first process using only the first compound, and then, in a subsequent second process, extracts and separates only polymers with urethane functional groups and / or polymers with amide functional groups from the waste polymer materials of mixed materials by adding the second compound.

[0034] Furthermore, in the separated mixture containing both polymers with urethane functional groups and polymers with amide functional groups, the temperature of the mixture can be adjusted to allow only the polymers with amide functional groups to settle, and the polymers with urethane functional groups can be extracted and separated from the filtrate using simple separation methods such as filtration. In the mixed solution from which the polymers with urethane functional groups have been extracted, depolymerization (based on alcoholysis) can be carried out simply by adding a depolymerization catalyst, yielding a renewable polyol feedstock with high purity.

[0035] Furthermore, when regenerating the polymer of the mixed material, the present invention can separate polymers having urethane functional groups and / or polymers having amide functional groups from the polymer of the mixed material, and separately perform depolymerization on polymers having urethane functional groups and polymers that can be depolymerized individually, such as polymers having ester functional groups. Different optimized conditions can be designed for efficient and rapid depolymerization of each polymer constituting the mixed material polymer. Therefore, it is possible to design an engineering process that enables the products obtained by depolymerization of each polymer to achieve high quality and high yield. Moreover, since the depolymerized products do not mix with each other, the purification process can also achieve the effect of minimizing unnecessary energy and material losses.

[0036] In particular, besides highly elastic polyurethane and nylon materials, this invention can also be used as a polymer fiber material comprising one or more polymers selected from cotton, linen, rayon, silk, acrylic, polyethylene, polypropylene, and polyester polymers as constituent components, such as the chemical recycling technology of blended fibers. Although the production and consumption of blended fibers continue to increase, because the material itself is processed into a complex and difficult-to-separate state similar to woven or knitted fabrics, most of the clothing discharged after use is currently disposed of through non-environmentally friendly methods such as landfill or incineration. By utilizing this invention, the discharged blended fibers can be chemically separated and the individual materials with different properties can be depolymerized and reduced back to their original state before synthesis. This not only simply improves the recycling rate of waste clothing but also contributes to achieving a circular economy in the clothing and fashion industry. Attached Figure Description

[0037] Figure 1 This is a conceptual diagram illustrating a method for regenerating a polymer material or blended fiber according to an embodiment of the present invention by separating and depolymerizing a polymer comprising a polymer having a urethane functional group and a polymer having an ester functional group, and which may also comprise a polymer of a blend material selected from cotton, linen, rayon, silk, acrylic, polyethylene, and polypropylene polymer materials, i.e., a synthetic polymer such as polyurethane or polyester.

[0038] Figure 2 This is a conceptual diagram illustrating a method for regenerating a polymer material or blended fiber that comprises a polymer having amide functional groups in addition to a polymer having urethane functional groups, according to one embodiment of the present invention.

[0039] Figure 3 The result is the selective dissolution of polyurethane by contacting the polymer material of the mixed material according to Example 1 with the first compound and the second compound, and the result is the shape of the polymer material of the mixed material observed by a stereomicroscope after contact times of (a) 5 minutes, (b) 10 minutes, (c) 30 minutes and (d) 180 minutes, respectively.

[0040] Figure 4 The chemical structure of polyester (raw material 2) in the polymer of raw material 1 and the location of protons are illustrated.

[0041] Figure 5 The chemical structure of polyurethane (raw material 3) in the polymer of raw material 1 and the location of protons are illustrated.

[0042] Figure 6 The nuclear magnetic resonance (NMR) hydrogen spectra were measured in the polymer materials of mixed materials, the single polymers constituting the polymer materials, and the polymers separated according to the method of Example 1. 1 H-NMR spectrum.

[0043] Figure 7 The infrared (IR) spectra of polyester and polyurethane polymers that can be separated from the polymer materials of the blend are illustrated.

[0044] Figure 8 This is a photograph illustrating the raw material of a polymer material from which colored impurities have been pre-removed from a mixed colored polymer material by applying different first compound temperatures.

[0045] Figure 9 The chemical structures and proton locations of polyols obtained by depolymerization after separating polyurethane from the polymer material of the mixed material, or raw materials used to synthesize spandex, are illustrated.

[0046] Figure 10 The nuclear magnetic resonance (NMR) hydrogen spectra were measured in the recycled polyols obtained by depolymerization of the separated polyurethanes and in polyols supplied by the reagent manufacturer. 1 H-NMR spectrum.

[0047] Figure 11 The infrared (IR) spectra of the recycled polyol obtained by depolymerization of the separated polyurethane and the polyol supplied by the reagent manufacturer are illustrated.

[0048] Figure 12 The process of separating and recycling individual polymers from nylon-polyurethane blends and the shapes of the products obtained at each step are illustrated.

[0049] Figure 13 The infrared (IR) spectra of the nylon-polyurethane blend polymer material and the nylon and polyurethane separated from it are illustrated.

[0050] Figure 14 The chemical structure of nylon and the location of protons are illustrated.

[0051] Figure 15 The 1H NMR spectrum was measured in polymer materials composed of nylon and polyurethane blends, as well as in the nylon and polyurethane separated from them. 1 H-NMR spectrum.

[0052] Figure 16It is the result of using a stereomicroscope to magnify and observe the steps of separating selectively soluble polymers from polymer materials of various mixed materials, and the application of insoluble polymers to fibrous materials that did not decompose after depolymerization.

[0053] Figure 17 These are magnified photographs taken using a stereomicroscope of acrylic acid and silk fibers within a polymer mixture, as well as acrylic acid and silk fibers recovered from the residual polymer after selective dissolution and depolymerization steps, and illustrations of the morphology of the recovered fibers themselves. Detailed Implementation

[0054] Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as commonly understood by one of ordinary skill in the art. Generally, the nomenclature used in this specification is that which is well-known and commonly used in the art.

[0055] Throughout this specification, when a part is described as "including" a certain element, unless otherwise expressly stated to the contrary, it does not mean that other elements are excluded, but rather that other elements may be included.

[0056] This invention provides a composition in which polymers having urethane functional groups and / or polymers having amide functional groups are selectively dissolved from a polymer material comprising one or more polymers having urethane functional groups and polymers having amide functional groups, and one or more polymers having cotton, linen, rayon, silk, acrylic, polyethylene, polypropylene, and ester functional groups.

[0057] Furthermore, the present invention provides a method for selectively dissolving polymers having urethane functional groups and / or polymers having amide functional groups from the polymer of the mixed material using the composition.

[0058] Furthermore, the present invention relates to a method for regenerating the polymer material of the mixed material, providing a method for regenerating the polymer material of the mixed material by selectively dissolving polymers having urethane functional groups and polymers having amide functional groups within the polymer of the mixed material and then filtering them, thereby separately separating polymers having amide functional groups and / or polymers having urethane functional groups from the polymer of the mixed material, and obtaining a high-purity / high-yield product by applying optimal depolymerization reaction conditions that conform to the type and characteristics of the polymers.

[0059] The polymer of the present invention refers to a polymer of mixed material containing polymers having urethane functional groups and polymers having amide functional groups; or a polymer of mixed material containing one or more polymers selected from the polymers having urethane functional groups and polymers having amide functional groups, and one or more polymers selected from cotton, linen, rayon, silk, acrylic, polyethylene, polypropylene, and polymers having ester functional groups as part or all of the constituent components; it may also include waste fibers of composite material composed of multiple polymer materials through manufacturing methods such as blending, fiber blending, and interlacing.

[0060] In this invention, the polymer having urethane functional groups can be a material with a high molecular weight structure, derived from polyols (or polyols) and possessing a soft structure and elastic resilience, and a molecular structure providing strong cohesion, bonded together by urethane bonds. This is also known as a polyurethane compound. The polymer having urethane functional groups can comprise polyurethanes with soft or rigid properties, and can be a foamed polyurethane manufactured by a foaming process to form bubbles, or a non-foamed polyurethane material mainly composed of a continuous polymer phase. It can contain polyethylene, high-density polyethylene, low-density polyethylene, polypropylene, polyethylene terephthalate, or combinations thereof, but is not limited to the polymer types described above. It can also be a mixture or copolymer of other known polymers, or a form containing various forms of organic and inorganic impurities.

[0061] As an example of the polymer having urethane functional groups, polyurethane is a polymer in the form of a multiblock copolymer containing urethane functional groups. It can be a polymer composed of hard segments (HS) with strong cohesiveness and thermodynamic stability that are adjacent to urethane bonds and have elasticity by forming soft segments (SS) that are flexible polymer chains, and has various types, forms and properties.

[0062] The hard segment (HS) constituting the polyurethane can be made of various forms of diisocyanate, but the most common are aromatic diisocyanates. Representative examples of aromatic diisocyanates that form the hard segment (HS) through polyurethane synthesis include monomolecular forms such as toluene diisocyanate (TDI), methylene diphenyl diisocyanate (MDI), and isophthalene diisocyanate (MXDI), as well as polymeric forms such as polyisocyanates, which are easily soluble in organic phases and thus easy to process. The soft segment (SS) constituting the flexible polymer chain of the polyurethane can be made of forms such as polyether polyols, polyester polyols, or poly(tetramethylene ether) glycol (PTMEG) (or polytetrahydrofuran (PolyTHF)).

[0063] Furthermore, the polymer with ester functional groups described in this invention can be a polymer formed by polycondensation of dicarboxylic acids and diols, wherein the dicarboxylic acid is selected from the group consisting of terephthalic acid, naphthalene dicarboxylic acid, diphenyl dicarboxylic acid, diphenyl ether dicarboxylic acid, diphenyl sulfone dicarboxylic acid, diphenoxyethane dicarboxylic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, decane dicarboxylic acid, cyclohexane dicarboxylic acid, trimellitic acid, pyromellitic acid, and combinations thereof, and the diol is selected from the group consisting of ethylene glycol, trimethylolpropionic acid, trimethylolpropionic acid, trimethylolpropionic acid, and combinations thereof. The group consisting of methyl glycol, 1,2-propanediol, tetramethylene glycol, neopentyl glycol, hexamethylene glycol, decamethylene glycol, dodecamethylene glycol, 1,4-cyclohexanediol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, dipropylene glycol, tripropylene glycol, tetrapropylene glycol, polypropylene glycol, di(tetramethylene) glycol, tri(tetramethylene) glycol, polytetramethylene glycol, pentaerythritol, 2,2-bis(4-β-hydroxyphenyl)propane, and combinations thereof.

[0064] For example, the polymer containing ester functional groups may be selected from polyethylene terephthalate (PET), polypropylene terephthalate (PPT), polyglycolic acid or polyglycolic acid (PGA), polylactic acid (PLA), polycaprolactone (PCL), polyhydroxyalkanoate (PHA), polyhydroxybutyrate (PHB), polyethylene adipate (PEA), polybutylene succinate (PBS), poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), polybutylene terephthalate (PBT), polytrimethylene terephthalate (PTT), polyethylene naphthalate (PEN), Vectran, and combinations thereof.

[0065] In this invention, the polymer having amide functional groups is a synthetic substance called nylon or polyamide, which is a polymer compound formed by amide bonds within its molecular structure. Examples of the polymer having amide functional groups include nylon 6, nylon 6,6, nylon 4,6, nylon 6,10, nylon 6,12, nylon 11, nylon 12, poly(m-phenylene adipamide) (MXD 6) nylon, and combinations thereof.

[0066] Next, with reference to the accompanying drawings, a method for regenerating a polymer comprising a polymer having urethane functional groups and / or a polymer having amide functional groups, and a polymer of a mixed material in which one or more polymers selected from cotton, linen, rayon, silk, acrylic, polyethylene, polypropylene, and polyester polymer materials are used as constituent components, and a composition for said method will be described in detail.

[0067] According to one embodiment of the present invention, in order to regenerate a polymer mixture having a urethane functional group and a polymer having an amide functional group; or a polymer mixture having one or more polymers selected from the urethane functional group and the amide functional group and one or more polymers selected from cotton, linen, rayon, silk, acrylic acid, polyethylene, polypropylene and polymers having ester functional groups as constituent components, a composition of polymers having urethane functional groups and polymers having amide functional groups selectively dissolved in the polymer mixture is used, the composition comprising: a first compound comprising one or more aromatic compounds having one or more alkoxy functional groups; and a second compound comprising one or more compounds having one or more alcohol functional groups.

[0068] The first compound may be derived from methoxybenzene, ethoxybenzene, butoxybenzene, 1,2-dimethoxybenzene, 1,3-dimethoxybenzene, 1,4-dimethoxybenzene, 1,2-diethoxybenzene, 1,3-diethoxybenzene, 1,4-diethoxybenzene, 1,2,3-trimethoxybenzene, 1,2,4-trimethoxybenzene, 1,3,5-trimethoxybenzene, 1,2,3-triethoxybenzene, 1,2,4-triethoxybenzene, 1,3,5-triethoxybenzene, 1,2,3,4-tetramethoxybenzene, 1,2,3,5-tetramethoxybenzene, 1,2,4,5-tetramethoxybenzene, 1-methoxy-2-methyl 1-Ethylbenzene, 1-methoxy-3-methylbenzene, 1-methoxy-4-methylbenzene, 1-ethyl-2-methoxybenzene, 1-ethyl-3-methoxybenzene, 1-ethyl-4-methoxybenzene, 1-ethoxy-2-methylbenzene, 1-ethoxy-3-methylbenzene, 1-ethoxy-4-methylbenzene, 1-ethoxy-2-ethylbenzene, 1-ethoxy-3-ethylbenzene, 1-ethoxy-4-ethylbenzene, 1-methoxy-2-propen-2-ylbenzene, 1-methoxy-3-propen-1-ylbenzene, 1-methoxy-3-propen-2-ylbenzene, 1-methoxy-4-propen-2-ylbenzene, 1-methoxy-4-[(E)] [-propenyl-1-yl]benzene (cis), 1-methoxy-4-[(E)-propenyl-1-yl]benzene (trans), methyl 2-ethoxybenzoate, methyl 3-ethoxybenzoate, methyl 4-ethoxybenzoate, ethyl 2-ethoxybenzoate, ethyl 3-ethoxybenzoate, ethyl 4-ethoxybenzoate, ethyl (E)-3-(4-hydroxy-3,5-dimethoxyphenyl)acrylate, ethyl 2-methoxybenzaldehyde, 3-methoxybenzaldehyde, 4-methoxybenzaldehyde, 2-ethoxybenzaldehyde, 3-ethoxybenzaldehyde, 4-ethoxybenzaldehyde, 2-propoxybenzaldehyde, 3-propoxybenzaldehyde, 2-propoxybenzaldehyde, 3-propoxybenzaldehyde, 4-propoxybenzaldehyde, 2-propoxybenzaldehyde, 3-propoxybenzaldehyde, 4-propoxybenzaldehyde, 2-propoxybenzaldehyde, 3-propoxybenzaldehyde, 4-propoxybenzaldehyde, 4-propoxybenzaldehyde Benzaldehyde, 2-butoxybenzaldehyde, 3-butoxybenzaldehyde, 4-butoxybenzaldehyde, 2-methoxybenzonitrile, 3-methoxybenzonitrile, 4-methoxybenzonitrile, 2-methoxybenzoic acid, 3-methoxybenzoic acid, 4-methoxybenzoic acid, 2,3-dimethoxybenzoic acid, 2,4-dimethoxybenzoic acid, 2,5-dimethoxybenzoic acid, 2,6-dimethoxybenzoic acid, 3,4-dimethoxybenzoic acid, 3,5-dimethoxybenzoic acid, 2,3-dimethoxy-4-methylbenzoic acid, 2,5-dimethoxy-4-methylbenzoic acid, 2,6-dimethoxy-4-methylbenzoic acid, 3,5-Dimethoxy-4-methylbenzoic acid, 2-ethoxybenzoic acid, 3-ethoxybenzoic acid, 4-ethoxybenzoic acid, 2-ethoxy-3-ethylbenzoic acid, 3-ethoxy-5-ethylbenzoic acid, 4-ethoxy-2-ethylbenzoic acid, 4-ethoxy-3-ethylbenzoic acid, 3-ethoxy-4-hydroxybenzoic acid, ethyl 2-methoxybenzoate, ethyl 3-methoxybenzoate, ethyl 4-methoxybenzoate, 2-hydroxy-3-methoxybenzoic acid, 2-hydroxy-4-methoxybenzoic acid, 2-hydroxy-5-methoxybenzoic acid, 2-hydroxy-6-methoxybenzoic acid, 2-hydroxy-4,5-dimethoxybenzoic acid, 2-hydroxy-4,6- Dimethoxybenzoic acid, 3-hydroxy-4-methoxybenzoic acid, 3-hydroxy-5-methoxybenzoic acid, 3-hydroxy-4,5-dimethoxybenzoic acid, 4-hydroxy-2-methoxybenzoic acid, 4-hydroxy-3-methoxybenzoic acid, 4-hydroxy-2,6-dimethoxybenzoic acid, 4-hydroxy-3,5-dimethoxybenzoic acid, 3,4-dihydroxybenzoic acid, 3-(4-hydroxy-3,5-dimethoxyphenyl)acrylic acid, 2-methoxyphenol, 3-methoxyphenol, 4-methoxyphenol, 2-methoxy-4-(propen-1-yl)phenol, 2-methoxy-4-propen-2-ylphenol, 4-methoxy-2-[(E)-propen-1- [4-hydroxy-2,6-dimethoxyphenol, 1-(4-methoxyphenyl)ethyl ketone, 2,3-dimethoxyphenol, 2,4-dimethoxyphenol, 2,5-dimethoxyphenol, 2,6-dimethoxyphenol, 3,4-dimethoxyphenol, 3,5-dimethoxyphenol, 2,6-dimethoxy-4-propen-2-ylphenol, 2-ethoxyphenol, 3-ethoxyphenol, 4-ethoxyphenol, 4-ethyl-2,5-dimethoxyphenol, 4-ethyl-2,6-dimethoxyphenol, 2-tert-butyl-4-methoxyphenol, 3-tert-butyl-4-methoxyphenol, 4-tert-butyl-2-methoxyphenol, 1-(4-hydroxy-2,6-dimethoxyphenyl)ethyl ketone, 1- (4-Hydroxy-3,5-dimethoxyphenyl) ethyl ketone, 2-hydroxy-3-methoxybenzaldehyde, 2-hydroxy-4-methoxybenzaldehyde, 2-hydroxy-5-methoxybenzaldehyde, 2-hydroxy-6-methoxybenzaldehyde, 3-hydroxy-2-methoxybenzaldehyde, 3-hydroxy-4-methoxybenzaldehyde, 3-hydroxy-5-methoxybenzaldehyde, 4-hydroxy-2-methoxybenzaldehyde, 4-hydroxy-3-methoxybenzaldehyde, 2-hydroxy-3,5-dimethoxybenzaldehyde, 2-hydroxy-4,6-dimethoxybenzaldehyde, 4-hydroxy-2,6-dimethoxybenzaldehyde, 4-hydroxy-3,5-dimethoxybenzaldehyde, 3-ethoxy-2-hydroxybenzaldehyde, Choose one or more compounds.

[0069] The second compound, as a monohydric or polyhydric alcohol, may be one or more compounds selected from straight-chain, branched, cyclic, or mixed forms of alcohols having 1 to 20 carbon atoms. The polyhydric alcohol may have two or more alcohol (OH) functional groups.

[0070] The first and second compounds, in addition to selectively dissolving polymers with urethane functional groups and / or polymers with amide functional groups, can also be used directly as compositions for depolymerizing individual polymers, such as polymers with ester functional groups and polymers with urethane functional groups.

[0071] Furthermore, when the weight ratio of the first compound relative to the second compound is within a specific range, the selective solubility efficiency of the polymer having urethane functional groups and the polymer having amide functional groups can be improved. In the composition that selectively dissolves the polymer having urethane functional groups and / or the polymer having amide functional groups, the weight ratio of the first compound relative to the second compound (weight (g) of the first compound / weight (g) of the second compound) is preferably from 0.01 to 100, more preferably from 0.1 to 10, and even more preferably from 0.5 to 2.

[0072] In the composition of polymers having urethane functional groups and / or polymers having amide functional groups that selectively dissolve into the polymer of the mixed material, the first compound and the second compound may be in a state of homogeneous mixing with each other, but the first compound and the second compound may also exist as a non-homogeneous unstable phase provided that the weight ratio range of the first compound / second compound is satisfied.

[0073] Furthermore, the present invention provides a method for selectively dissolving polymers having urethane functional groups and / or polymers having amide functional groups from a polymer mixture comprising one or more polymers selected from the polymers having urethane functional groups and the polymers having amide functional groups, and one or more polymers selected from cotton, hemp, rayon, silk, acrylic acid, polyethylene, polypropylene, and polymers having ester functional groups as constituent components.

[0074] The dissolution method is characterized in that: the polymer of the mixed material is sequentially or simultaneously contacted with one or more first compounds comprising aromatic compounds having one or more alkoxy functional groups and one or more second compounds comprising compounds having one or more alcohol functional groups, thereby selectively dissolving polymers having urethane functional groups and / or polymers having amide functional groups within the polymer of the mixed material.

[0075] The weight ratios of the first and second compounds are the same as those described in the composition description above, so they will not be repeated.

[0076] The first and second compounds may be substances that are solid at room temperature, preferably liquid when heated to the temperature range in order to selectively dissolve polymers having urethane functional groups and / or polymers having amide functional groups, and preferably at least one of the compounds is liquid and can dissolve the other compounds.

[0077] When the polymer of the mixed material is sequentially contacted with the first compound and the second compound, the second compound may be contacted with the polymer of the mixed material first. However, it is preferable to remove unwanted impurities by contacting the first compound with the composite polymer first. For example, by contacting the first compound with the polymer of the colored mixed material, a series of processes can be performed to first extract and remove pigments and other organic and inorganic impurities (such as dyes or pigments) contained in the polymer of the colored mixed material.

[0078] At this point, the mass of the first compound compared to the mass of the polymer in the mixed material can be in the range of 0.1 to 1000 times, and the temperature at which the first compound contacts the polymer in the mixed material can be between 100°C and 180°C. At temperatures below 100°C, incomplete extraction and removal of impurities may occur. At temperatures above 180°C, contamination of the mixture may occur due to the decomposition of impurities, or selective dissolution of subsequent polymers with urethane functional groups and / or amide functional groups due to the initial depolymerization of the polymer in the mixed material. This can lead to a decrease in the individual depolymerization performance of the separated polymers and the quality of the final product, further deteriorating the reusability of the polymer in the mixed material.

[0079] During the removal of impurities, purging with an inert gas such as nitrogen can be performed simultaneously, or the process can be carried out after prior purging. The contact time can be varied depending on the amount of polymer in the mixed material, the temperature at contact, and the amount of the first compound, but can range from 1 minute to 24 hours. Furthermore, to ensure smooth contact, the mixture of the first compound and the polymer in the mixed material can be stirred, and the first compound can be added initially or supplied in a continuous flow. Additionally, the first compound can be recovered from the extract generated during the impurity removal process using separation methods such as distillation, evaporation, and drying, and then resupplyed to the impurity removal process, or used when adjusting the amount of polymer relative to the first compound.

[0080] For compositions prepared by the process of removing impurities using the first compound described above, consisting of a polymer of a mixed material and a mixture of the first compound, a second compound can be added in place or after transfer to a separate process located outside, thereby performing a process for selectively dissolving polymers having urethane functional groups and / or polymers having amide functional groups. Without performing the impurity removal process described above, both the first and second mixtures can be added to the polymer of the mixed material simultaneously, thereby selectively dissolving polymers having urethane functional groups and polymers having amide functional groups. As described above, the weight ratio of the first compound relative to the second compound (weight (g) of the first compound / weight (g) of the second compound) needs to be adjusted to 0.01 to 100.

[0081] In the process of selectively dissolving polymers having urethane functional groups and / or polymers having amide functional groups from polymers of mixed materials, purging with an inert gas such as nitrogen can be performed simultaneously, or the process can be performed under conditions where purging has been performed in advance.

[0082] In the process of selectively dissolving polymers having urethane functional groups and / or polymers having amide functional groups from the polymer of the mixed material, the temperature can be maintained for 1 minute to 24 hours, during which stirring can be carried out in parallel to allow the first compound and the second compound to come into smooth contact with the polymer of the mixed material.

[0083] After selectively dissolving the polymers having urethane functional groups and / or the polymers having amide functional groups, the undissolved polymers having ester functional groups and polymers such as cotton, linen, rayon, silk, acrylic acid, polyethylene, and polypropylene can be separated from the mixed solution of the polymers having urethane functional groups and / or the polymers having amide functional groups dissolved by means of the first and second compounds. As a separation method, it can be performed by means such as filtration, centrifugation, or separation after settling; however, any means that can separate the undissolved polymers from the mixture can be used without limitation. The separation method can be performed in parallel with the process of selectively dissolving the polymers having urethane functional groups and the polymers having amide functional groups.

[0084] In cases where the polymer in the mixed material does not contain polymers with amide functional groups, in order to selectively dissolve only polymers with urethane functional groups, the prepared mixture containing the first and second compounds can be heated and maintained at a temperature range of 100°C to 180°C. Temperatures below 100°C may result in the polyurethane failing to dissolve, while temperatures above 180°C may cause depolymerization of the polymers within the mixed material, potentially leading to difficulties in recovering high-quality products due to various side reactions.

[0085] When both urethane functional groups and amide functional groups are present in the polymer of the mixed material and the two are selectively dissolved, the temperature range is preferably 135°C to 180°C, more preferably 140°C to 170°C, and even more preferably 150°C to 155°C.

[0086] During the dissolution process, a mixed solution is generated containing both a polymer with urethane functional groups and a polymer with amide functional groups. The temperature of the extracted mixed solution can be adjusted to allow only the polymer with amide functional groups to settle, and the polymer with amide functional groups and the polymer with urethane functional groups can be separated by a conventional solid-liquid separation method.

[0087] The temperature range within which only the polymer with amide functional groups settles by adjusting the temperature of the extracted mixed solution containing the dissolved polymer with urethane functional groups is preferably from 10°C to 130°C, more preferably from 25°C to 120°C, and even more preferably from 70°C to 100°C. When the temperature for settling the polymer with amide functional groups exceeds 130°C, the settling rate of the polymer with amide functional groups may slow down or complete settling may not occur. Conversely, if the solution is left at a temperature below 10°C for more than one day (24 hours), some of the polymer with urethane functional groups may also settle.

[0088] Furthermore, the present invention provides a depolymerization or regeneration method for reusing a polymer material comprising a blend of polymers having urethane functional groups and polymers having amide functional groups; or a blend of polymer materials comprising, in addition to polymers containing said polymers having urethane functional groups and polymers having amide functional groups, one or more polymers selected from cotton, hemp, rayon, silk, acrylic acid, polyethylene, polypropylene, and polymer materials having ester functional groups as constituent components.

[0089] The depolymerization method is characterized by comprising: (a) a polymer material comprising a mixture of a polymer having a urethane functional group and a polymer having an amide functional group; or a polymer material comprising a mixture of one or more polymers selected from the polymers having urethane functional groups and polymers having amide functional groups and one or more polymers selected from cotton, linen, rayon, silk, acrylic, polyethylene, polypropylene and polymers having ester functional groups as a constituent component, and a first compound comprising one or more aromatic compounds having one or more alkoxy functional groups and a compound comprising one or more alcohol functional groups. The steps include: (a) contacting the second compound above to selectively dissolve only the polymers having urethane functional groups and / or polymers having amide functional groups in the mixed polymer material; (b) filtering the mixed solution generated after the selective dissolution to separate the polymers having urethane functional groups and / or polymers having amide functional groups from the polymer material of the mixed material to a polymer material composed of polymers having ester functional groups and one or more polymers selected from cotton, hemp, rayon, silk, acrylic acid, polyethylene and polypropylene; and (c) a depolymerization reaction step of depolymerizing the polymers separated in the solid phase.

[0090] Furthermore, when the polymer of the mixed material contains both a polymer having a urethane functional group and a polymer having an amide functional group, the present invention may further include, after step (c), a step of separating the polymer having a urethane functional group by adjusting the temperature of the separated mixture containing the polymer having a urethane functional group and the polymer having an amide functional group so that only the polymer having an amide functional group settles; and further may include, a step of depolymerization reaction of the separated polymer having a urethane functional group, in which the polymer has a urethane functional group is depolymerized.

[0091] In the case where the polymer of the mixed material does not contain polymers with amide functional groups but contains polymers with urethane functional groups, step (d) may be omitted and the process may directly include: (e) a depolymerization reaction step of depolymerizing the separated polymers with urethane functional groups.

[0092] In one embodiment of the present invention, the polymer depolymerized in step (c) may be a polymer having ester functional groups. In this case, step (c) is characterized in that the depolymerization of the polymer having ester functional groups may be carried out by one or more of currently known depolymerization methods such as hydrolysis, glycolysis, methanolysis, ethanolysis, ammonolysis, and aminolysis.

[0093] In the case where the polymer separated into a solid phase in step (c) also contains substances that do not undergo depolymerization, the characteristic is that the substances that do not undergo depolymerization can be separated from the reaction products by relatively simple methods such as filtration or centrifugation.

[0094] Furthermore, one embodiment of the present invention is characterized in that the depolymerization of the polymer having urethane functional groups in step (e) can be carried out by adding a catalyst for depolymerization of the polymer having urethane functional groups to the filtered filtrate.

[0095] The catalyst for depolymerization may be one or more selected from the group consisting of metal catalysts such as alkali metal hydroxides, alkaline earth metal hydroxides, alkali metal acetates, alkaline earth metal acetates, alkali metal carbonates, alkali metal bicarbonates, alkaline earth metal carbonates, alkali metal oxides, or organic compounds such as guanidines or amines.

[0096] In the depolymerization composition, the total mass of the catalyst may be in the range of 0.001 to 0.1 times the mass of the polymer having urethane functional groups, and the depolymerization temperature may be in the temperature range of 100°C to 170°C, preferably in the temperature range of 140°C to 165°C.

[0097] When depolymerizing the polymer having urethane functional groups, the weight of the polymer having urethane functional groups may be from 1 wt% to 200 wt% compared to the total weight of the first compound and the second compound, and the weight ratio of the first compound to the second compound, i.e., the weight ratio of the first compound to the second compound, may be from 0.05 to 20, preferably from 0.1 to 10, and more preferably from 0.5 to 2.

[0098] In step (d), after the polymer with amide functional groups has settled, the first compound and / or the second compound may be added to the separated polymer solution with urethane functional groups to adjust the weight ratio of the first compound and / or the second compound to the polymer with urethane functional groups. However, for engineering convenience, it is preferable to perform the depolymerization reaction without adding the first compound and / or the second compound.

[0099] Next, a pretreatment and depolymerization method for chemically reusing mixed polymer materials according to one embodiment of the present invention will be described in more detail through examples, comparative examples, and experimental examples.

[0100] Raw Material 1

[0101] Raw material 1 is prepared by cutting a blended fiber (blended fiber) containing 86% polyester and 14% polyurethane (spandex) by weight into small square pieces with each side approximately 2 cm in size.

[0102] Raw Material 2

[0103] Raw material 2 is prepared by cutting colorless fibers containing 100% polyester into small square pieces with one side approximately 2 cm in size, as these fibers are colorless due to the absence of added dyes.

[0104] Raw Material 3

[0105] Raw material 3 was prepared by cutting spandex yarn, which is colorless due to the absence of added dyes and is composed of 100% polyurethane, into lengths of less than 1 cm.

[0106] Raw Material 4

[0107] Raw material 4 is prepared by cutting fibers containing 86% polyester and 14% polyurethane (spandex) by weight and doped with black dye (dye: Dystar Dianix Deep Black Plus, weight ratio: 2.0% owf) into small square pieces with one side of about 2cm.

[0108] Raw Material 5

[0109] Raw material 5 is prepared by cutting a blend of fibers containing 86% polyester and 14% polyurethane (spandex) by weight and doped with azo red dye (dye: Disperse Red 1, weight ratio: 1.5% owf) into small square pieces with one side of about 2 cm.

[0110] Raw Material 6

[0111] Raw material 6 is prepared by adding a mixture of polypropylene nonwoven fabric, cotton, and nylon to the fibers of raw material 1. The mixture comprises 64.5% polyester, 10.5% polyurethane, 10% polypropylene, 10% cotton, and 5% nylon by weight. The resulting material has a size of less than 3 cm on one side.

[0112] Raw Material 7

[0113] Raw material 7 is prepared by cutting fibers of a mixed material containing 75% nylon (nylon 6) and 25% polyurethane (spandex) by weight and doped with a light purple (lavender) alkaline dye (weight ratio: less than 2.0%) into small square pieces with one side of about 2 cm.

[0114] Raw Material 8

[0115] The material was prepared by cutting a mixed fiber containing 60% cotton, 30% rayon and 10% polyurethane into small square pieces with each side approximately 2cm in size, as raw material 8.

[0116] Raw Material 9

[0117] The material was prepared by cutting a mixed material fiber containing 75% cotton, 20% rayon and 5% polyurethane by weight into small square pieces with each side approximately 2cm in size, as raw material 9.

[0118] Raw Material 10

[0119] The material 10 was prepared by cutting a mixed material fiber containing 65% cotton, 32% rayon and 3% polyurethane by weight into small square pieces with one side of about 2cm.

[0120] Raw Material 11

[0121] Raw material 11 is prepared by cutting a blend of 60% polyester, 35% cotton and 5% polyurethane (the front side of the fiber is made of cotton-polyurethane material and the back side is made of polyester-polyurethane material) into small square pieces with one side of about 2 cm.

[0122] Raw Material 12

[0123] The material 12 was prepared by cutting a mixed material fiber containing 49% polyester, 44% Tencel and 7% polyurethane by weight into small square pieces with one side of about 2cm.

[0124] Raw Material 13

[0125] Raw material 13 was prepared by cutting a blend of fibers containing 54% polyester, 38% nylon (nylon 6,6) and 8% polyurethane by weight into small square pieces with one side approximately 2 cm in size.

[0126] Raw Material 14

[0127] Raw material 14 is prepared by adding 20% ​​of raw material 8, raw material 12 and 40% of raw material 13 by weight, and adding 10% of silk (silk) cut to a width of about 2 cm on one side and acrylic fiber respectively.

[0128] Selective dissolution of polyurethane from hybrid polymer materials

[0129] Example 1

[0130] (a) Selective dissolution of polyurethane: After preparing a mixed solvent using 35g of anisole as the first compound and 60g of ethylene glycol as the second compound, the solvent was placed in a 250ml autoclave manufactured under high pressure and heated, with the internal temperature maintained at 150°C using proportional-integral-derivative (PID) control. After the temperature stabilized, 10g of the fiber from the mixed material prepared as raw material 1 was added, and the mixture was stirred at a speed of 350rpm or higher using a top-mounted stirrer equipped with a polytetrafluoroethylene (PTFE) impeller. When the required fiber contact time was reached, the inlet of the container was opened and the fiber was removed using tweezers. After washing in approximately 50ml of ethanol solution prepared in a glass bottle, the fiber was transferred to a glass evaporating dish. The solution was then placed in a vacuum dryer maintained at low pressure (≤2mmHg) using a vacuum pump and at 60°C using an internal heater for drying for at least 12 hours.

[0131] (b) Determination of polyurethane content in the mixed polymer material: Polyurethane is dissolved from the mixed polymer fibers and discharged in liquid form by contact with a mixed solution composed of the first and second compounds. The polyurethane extraction ratio is estimated by determining the polyurethane content in the fiber sample. For this purpose, 30 mg of the mixed polymer fiber sample is uniformly dissolved in 0.7 ml of a solution composed of trifluoroacetic acid- d (Trifluoroacetic acid-) d TFA- d ) and dichloromethane d 2(dichloromethane- d After mixing the solvents of 2, CD2Cl2 and CD2Cl2 in a weight ratio of 1:10, the proton NMR spectrum was analyzed by nuclear magnetic resonance (NMR) spectroscopy (model: Bruker A VANCE II+500MHz). 1 The 1H-NMR spectrum was measured, and the polyurethane content was deduced from the relative area ratio of the observed characteristic peaks. Prior to this, the 1H NMR spectra of samples prepared according to different mass ratios of raw material 2 (100% polyester) and raw material 3 (100% polyurethane) (samples mixed with polyurethane at weight ratios of 0%, 4%, 8%, 12%, 16%, and 20%) were first analyzed. 1The ¹H-NMR spectra were measured, and the relative area ratios of the characteristic peak values ​​of polyester (δ(ppm) = 8.16, 4.79, 4.63, 4.19, 4.11) and polyurethane (δ(ppm) = 7.26, 7.19, 3.67, 3.47, 1.78, 1.70, 1.41, 1.30, 0.44, 0.14) were correlated with the mass ratio of the polymer composition to obtain calibration curves.

[0132] The proportion of polyurethane in the mixed polymer material that is selectively dissolved and removed is calculated using the following formula.

[0133] - PU extraction rate; X PU (%) = 100 - (M PU / M PU,0 ) × 100 (Formula 1)

[0134] In the formula, M PU,0 M is the initial mass of polyurethane within the mixed polymer material. PU It refers to the mass of polyurethane within a mixed polymer material that, although in contact with a mixed solution consisting of the first and second compounds, does not undergo selective dissolution.

[0135] (c) Separation and Recovery of Individual Polymers: Following process (b), after determining the point at which the selective dissolution of polyurethane is achieved through sufficient contact between the mixed solution of the first and second compounds and the polymer material in process (a), the fibers and the mixture containing dissolved polyurethane within the pressure vessel are filtered using polytetrafluoroethylene (PTFE) membrane filter paper (pore size 0.45 μm). Undissolved fibers remain on the filter paper, and the filtrate is transferred to a separating funnel to induce liquid-liquid phase separation. The separated phase consists of two layers: an upper organic solvent layer containing a high concentration of the first compound, and a lower hydrophilic solvent layer containing a high concentration of the second compound. Most of the dissolved polyurethane appears as a white, turbid solution, and phase separation occurs because it remains mixed with the organic solvent layer. Further phase separation is induced by adding excess hexane and water, thereby separating and removing the first and second compounds. After transferring the final separated product to a 50 ml flask, a rotary evaporator was used to remove the organic solvent present in the organic phase, thereby recovering the white solid polyurethane.

[0136] (d) Characteristic analysis of the separated polymers: For each separated polymer, in addition to performing the proton nuclear magnetic resonance spectroscopy described in process (b), 1 In addition to H-NMR spectroscopy analysis, a total reflectance infrared spectroscopy (ATR / FT-IR; Bruker ALPHA II) instrument was used to observe its structural properties. It was observed that the polyurethane dissolved due to contact with the mixed solution of the first and second compounds, and thus the polymer material remaining in the solid phase lost its elasticity. The shape changes of the woven fabric were then observed using a stereomicroscope (model: Olympus SZ61).

[0137] Example 2

[0138] Except that the amount of anisole added as the first compound was increased to 70g (twice), the individual polymers were separated from the polymer material of the mixed material by selective dissolution of polyurethane and their properties were analyzed in the same manner as in Example 1.

[0139] Comparative Example 1

[0140] In manufacturing the mixed solvent, except that anisole as the first compound and ethylene glycol as the second compound were not used simultaneously, but only 70g of anisole equivalent to the first compound was used, the individual polymers were separated from the polymer material of the mixed material by selective dissolution of polyurethane and their properties were analyzed in the same manner as in Example 1.

[0141] Comparative Example 2

[0142] In the preparation of the mixed solvent, except that anisole, which is the first compound, and ethylene glycol, which is the second compound, are not used simultaneously, only 70g of ethylene glycol, which is equivalent to the second compound, are used. The individual polymers are separated from the polymer material of the mixed material by selective dissolution of polyurethane and their properties are analyzed.

[0143] Table 1 shows, as a function of time, the proportion of polyurethane removed from the mixed polymer by selective dissolution after contacting a polymer raw material composed of polyester and polyurethane with a first compound and / or a second compound at a temperature of 150°C. The mixed polymer raw material 1 used here is a blended material in the form of a woven fabric made of polyester and polyurethane yarns woven in a cross-weft (horizontal) and warp (vertical) configuration. It is known that it is technically difficult to disassemble and further differentiate or physically separate this material. Therefore, this invention proposes a method for reuse by selectively and completely dissolving one component constituting the mixed material and converting it into other phases, followed by physical separation. The method of selectively dissolving polyurethane can be used, and as the solvent used here, it is more advantageous to use a mixture of compounds with two different chemical structures, as shown in Examples 1 and 2 of Table 1, compared to a single compound.

[0144] The first compound exhibits strong interactions with hard segments of a rigid structure that maintain strong cohesion and thermodynamic stability through their proximity to urethane bonds. The second compound, on the other hand, has a high affinity for soft segments that provide elasticity by forming flexible polymer chains. Therefore, the combined use of both compounds may yield more significant results. The first compound can be an aromatic compound with alkoxy functional groups that strongly interact with both the hard segments of the polyurethane and the urethane bonds. The second compound can be an alcohol compound that is expected to have a high thermodynamic affinity for the polyols constituting the soft segments, thereby significantly improving its solubility. The results in Table 1 specifically and fully illustrate the effects described above.

[0145] Table 1

[0146] Referring to the results of Comparative Examples 1 and 2, where only the first compound (anisole) or the second compound (ethylene glycol) was used as the extraction solvent to contact the polyester-polyurethane blend, it can be confirmed that although some selective dissolution of the polyurethane occurred after a contact time of 2 hours, the removal rate of polyurethane remained below 50%, with only a very limited amount dissolving, even under prolonged storage conditions. In contrast, in Examples 1 and 2, where a mixed solvent containing both anisole and ethylene glycol was used, selective dissolution of the polyurethane occurred rapidly. In particular, in Example 2, where anisole and ethylene glycol were added in a similar weight ratio, all the polyurethane dissolved rapidly within a contact time of 20 minutes. This indicates that a solvent containing both the first and second compounds is very effective for the selective dissolution of polyurethane.

[0147] Figure 3 The results are obtained by observing the shape of the mixed polymer material obtained in Example 1 according to the contact time using a stereomicroscope. As the contact time progressed, selective dissolution of polyurethane occurred in the mixed polymer material, which confirmed that the woven fabric gradually transformed into a loose fibrous structure due to the increasing mesh size, but the elasticity decreased significantly due to the increased polyester concentration.

[0148] exist Figure 4 as well as Figure 5 The chemical structures and proton positions of the polyester (raw material 2) and polyurethane (raw material 3), which are polymers that constitute the mixed material of raw material 1, are illustrated.

[0149] To confirm the structural characteristics of the polymer separated / recovered from the mixed polymer material (raw material 1) by means of selective dissolution of polyurethane according to the method of Example 1, proton nuclear magnetic resonance spectroscopy was performed on raw material 2 (polyester) and raw material 3 (polyurethane) having a single polymer component, as well as the separated polymer sample. 1 H-NMR) test. In Figure 6 The obtained spectra were compared and illustrated. It can be confirmed that the characteristic peaks of the separated / recovered polymers are highly consistent with the characteristic peaks of the single polymers (raw material 2 and raw material 3). This fully demonstrates that the method of Example 1 can very effectively separate polymer components from polymer materials of mixed materials through the selective dissolution of polyurethane.

[0150] <Selection of compounds effective for the selective dissolution of polyurethane>

[0151] Next, examples and comparative examples implemented to confirm the effectiveness of compound combinations in selectively dissolving polyurethane will be described.

[0152] (1) Variations of the first compound

[0153] Example 3

[0154] In the preparation of the mixed solvent, except that 1,2-dimethoxybenzene was used instead of anisole as the first compound, the individual polymers were separated from the polymer material of the mixed material by selective dissolution of polyurethane and their properties were analyzed in the same manner as in Example 1.

[0155] Example 4

[0156] In the preparation of the mixed solvent, except that 1,4-dimethoxybenzene was used instead of anisole as the first compound, the individual polymers were separated from the polymer material of the mixed material by selective dissolution of polyurethane and their properties were analyzed in the same manner as in Example 1.

[0157] Example 5

[0158] In the preparation of the mixed solvent, except that 1,3,5-trimethoxybenzene was used instead of anisole as the first compound, the individual polymers were separated from the polymer material of the mixed material by selective dissolution of polyurethane and their properties were analyzed in the same manner as in Example 1.

[0159] Example 6

[0160] In the preparation of the mixed solvent, except that ethoxybenzene was used instead of anisole as the first compound, the individual polymers were separated from the mixed polymer material by selective dissolution of polyurethane and their properties were analyzed in the same manner as in Example 1.

[0161] Example 7

[0162] In the preparation of the mixed solvent, except that guaiacol was used as the first compound instead of anisole, the individual polymers were separated from the polymer material of the mixed material by selective dissolution of polyurethane and their properties were analyzed in the same manner as in Example 1.

[0163] Comparative Example 3

[0164] In the preparation of the mixed solvent, except that p-xylene was used as the first compound instead of anisole, the individual polymers were separated from the mixed polymer material by selective dissolution of polyurethane and their properties were analyzed in the same manner as in Example 1.

[0165] In Examples 1, 3 to 7, and Comparative Example 3, the selective dissolution effect of polyurethane was compared when the type of the first compound was changed during the separation of individual polymers from a mixed polymer material. In all experimental examples, only the type of the first compound was changed for performance comparison while other conditions remained constant. It was confirmed that in the examples using compounds having at least one alkoxy functional group, the dissolution of polyurethane occurred very selectively and efficiently. In particular, 1,2-dimethoxybenzene (1,2-DMB) exhibited very efficient polyurethane dissolution performance in which alkoxy functional groups substituted onto aromatic rings were adjacent to each other. It can be speculated that this is because when multiple alkoxy functional groups are arranged in the same direction, the aromatic structure at the center of the hard segment within the polyurethane structure and the urethane bond at the bilaterally symmetrical position interact strongly with the alkoxy functional groups of 1,2-dimethoxybenzene (1,2-DMB).

[0166] Furthermore, Comparative Example 3 confirmed the effectiveness of using only an aromatic hydrocarbon compound, p-xylene, as the first compound to selectively dissolve polyurethane from the mixed material. p-xylene, with a boiling point of approximately 138°C, is a relatively stable and low-polarity good solvent, often used in conjunction with toluene for dissolving various polymers. It is a compound with a central aromatic ring and methyl groups on the outside of the substituents. Therefore, although structurally similar to 1,4-dimethoxybenzene used as the first compound in Example 4, the functional group directly substituted onto the aromatic ring is methyl rather than methoxy. It was confirmed that in Example 4 using 1,4-dimethoxybenzene, most of the polyurethane dissolved when the contact time with the mixed polymer material was maintained at 150°C for 2 hours. However, in Comparative Example 3, where p-xylene was used as the first compound, less than half of the polyurethane dissolved in the mixed solvent. This clearly demonstrates that simply combining solvents with high or expected affinity for the polymer is not necessarily effective for selectively dissolving polyurethane from the mixture.

[0167] Table 2

[0168] (2) Variations of the second compound

[0169] Example 8

[0170] In the preparation of the mixed solvent, except that diethylene glycol (DEG) was used as the second compound instead of ethylene glycol, the individual polymers were separated from the polymer material of the mixed material by selective dissolution of polyurethane and their properties were analyzed in the same manner as in Example 1.

[0171] Example 9

[0172] In the preparation of the mixed solvent, except that triethylene glycol (TEG) was used as the second compound instead of ethylene glycol, the individual polymers were separated from the polymer material of the mixed material by selective dissolution of polyurethane and their properties were analyzed in the same manner as in Example 1.

[0173] Example 10

[0174] In the preparation of the mixed solvent, except that 1-octanol was used as the second compound instead of ethylene glycol, the individual polymers were separated from the mixed polymer material by selective dissolution of polyurethane and their properties were analyzed in the same manner as in Example 1.

[0175] Comparative Example 4

[0176] In manufacturing the mixed solvent, except that n-decane was used as the second compound instead of ethylene glycol, the individual polymers were separated from the mixed polymer material by selective dissolution of polyurethane and their properties were analyzed, following the same method as in Example 1.

[0177] Table 3 compares the selective dissolution effect of polyurethane when the type of the second compound is changed during the separation of individual polymers from the mixed polymer material. In all the experimental examples in Table 3 (Examples 1, 8 to 10, and Comparative Example 4), only the type of the second compound was changed while other conditions remained constant for performance comparison. The results of Examples 1 and 8 to 10 confirm that polyurethane dissolution occurs very efficiently and selectively when a compound having at least one alcohol functional group (the second compound) and an aromatic compound having an alkoxy functional group (the first compound) are used in combination. Similar performance in selective dissolution of polyurethane was observed not only in the case where ethylene glycol with an alcohol functional group attached to the end of the hydrocarbon chain structure was used as the second compound (Example 1), but also in the case where diols such as diethylene glycol or triethylene glycol, which form larger molecular structures by combining multiple diols together, were used as the second compound (Examples 8 and 9). In particular, even in Example 10, where n-octanol, which has a long hydrocarbon chain structure but only one alcohol functional group at the end, was used as the second compound, the dissolution of polyurethane occurred very efficiently.

[0178] Furthermore, as another example of the second compound, it can be confirmed that when using decane, which has a similar chain length to n-octanol (Example 10) but is composed only of hydrocarbons and lacks alcohol functional groups, almost no polyurethane dissolution occurs. This confirms that, in order to improve the selective dissolution performance of polyurethane from mixed polymer materials, not only the selection of the first compound but also the selection of an appropriate second compound is crucial.

[0179] Table 3

[0180] Figure 7This is a comparison of representative information from the infrared (IR) spectra measured in the polyester and polyurethane separated by the embodiments described above, and in the starting materials, namely raw materials 2 and 3. To compare the structure and compositional characteristics of the polymers separated by the method of the embodiments, not only the polyester and polyurethane separated by the method of the embodiments, but also the spectra of raw materials 2 and 3, which are equivalent to single polymers, are illustrated. The polymers separated by the method of the embodiments exhibit a spectral morphology highly similar to that of the single polymers. This fully demonstrates that the method of selectively dissolving polyurethane and thereby separating the polymer composition according to the present invention, i.e., when the mixed polymer material is contacted with a solvent composed of a mixture of the first and second compounds for a certain period of time under heating, selective dissolution of polyurethane occurs, thereby allowing for very efficient separation of the polymer components constituting the mixed material. Because selective dissolution of polyurethane occurs rapidly with just simple contact, the individual polymers (polyester and polyurethane) constituting the mixed material can be perfectly separated from each other by a relatively simple and efficient method. <Influence of Extraction Temperature on the Selective Dissolution of Polyurethane>

[0181] Next, examples and comparative examples implemented to confirm the effect of extraction temperature on the selective dissolution of polyurethane will be described.

[0182] Comparative Example 5

[0183] In addition to maintaining the internal temperature of the container at 90°C and stirring for 24 hours, the individual polymers were separated from the mixed polymer material by selective dissolution of polyurethane and their properties were analyzed, following the same method as in Example 2.

[0184] Example 11

[0185] In addition to maintaining the internal temperature of the container at 100°C and stirring for 24 hours, the individual polymers were separated from the mixed polymer material by selective dissolution of polyurethane and their properties were analyzed, following the same method as in Example 2.

[0186] Comparative Example 6

[0187] In addition to maintaining the internal temperature of the container at 190°C and stirring for 1 hour, the individual polymers were separated from the mixed polymer material by selective dissolution of polyurethane and their properties were analyzed, following the same method as in Example 2.

[0188] Table 4 shows the results of confirming the dissolution rate of polyurethane at contact temperature when separating individual polymers from the polymer material of the mixed material by selective dissolution of polyurethane. It can be confirmed that when placed at a contact temperature of 100°C for more than 24 hours (Example 11), the dissolution of polyurethane occurs slowly but gradually. However, it can be confirmed that at a contact temperature of 90°C, which is further reduced by 10°C as shown in Comparative Example 5, the dissolution rate decreases sharply.

[0189] Furthermore, in Comparative Example 6, where a mixed solvent consisting of the first and second compounds was kept at a high temperature (190°C) and contacted with the polymer material of the mixed material, excessive color change (yellowing) was observed due to a significant increase in the deterioration and oxidation of the polyurethane, and polyester decomposition occurred. After exposure to the high temperature for approximately one hour, a portion of the liquid product (filtrate) was taken and analyzed using high-performance liquid chromatography (HPLC), confirming that the polyester itself underwent partial depolymerization. It was confirmed that the yield of the oligomers (including dimers) generated due to the depolymerization of the polyester was approximately 4.1%.

[0190] Table 4

[0191] <Impurity removal effect when applying the first compound and the second compound sequentially>

[0192] Next, examples and comparative examples will be described to confirm the impurity removal effect in polymer materials containing organic impurities in addition to polymers.

[0193] Comparative Example 7

[0194] Approximately 10g of the fiber containing the black dye-doped composite material prepared as raw material 4 was placed into a 250ml flask containing 70g of anisole (compound 1), which had been preheated and maintained at 90°C. The dye was then extracted by stirring at 300rpm for approximately 5 minutes using a magnetic stirrer. After removing the colored mixture due to the dissolved dye, the solution was transferred to 70g of anisole maintained at the same temperature for washing. This washing was repeated up to three times until no more dye dissolved into the anisole used for washing.

[0195] The color of the blended fibers was measured using a spectrophotometer (manufactured by Konica Minolta, model CM-3600A), and the result is denoted as L. a b Value. With L a b The values ​​represented are coordinates of a color space standardized by the International Commission on Illumination (CIE), where L... It represents brightness as a numerical value ranging from 0 (black) to 100 (white), while a and b These are numerical values ​​expressed as positive / negative values ​​based on the complementary color axes of red / green and yellow / blue, respectively. Furthermore, the variation in dyeing amount can be derived from the K / S value using the Kubelka-Munk formula, expressed as follows.

[0196] - K / S = (1-R) 2 / (2×R) (Formula 2)

[0197] Where K represents the absorption coefficient, S represents the scattering coefficient, and R represents the reflectance of monochromatic light. The K / S value, representing the apparent dye weight, can be calculated from the reflectance of the dyed material measured at the dye's maximum absorption wavelength.

[0198] After a solution consisting of fibers of a blend obtained through a washing process and approximately 70g of anisole was placed into a 200ml autoclave containing 35g of ethylene glycol equivalent to the second compound and heated to 150°C, the polymers were separated from the blend by selective dissolution of polyurethane and their properties were analyzed, following the same method as in Example 1.

[0199] Example 12

[0200] When removing dye impurities from the colored blended material fibers of raw material 4, except that the temperature of the anisole used as the first compound was maintained at 110°C, the dye impurities were removed in the same manner as in Comparative Example 7. Then, each polymer was separated from the polymer material of the blended material by selective dissolution of polyurethane and its properties were analyzed.

[0201] Example 13

[0202] When removing dye impurities from the colored blended material fibers of raw material 4, except that the temperature of the anisole used as the first compound was maintained at 130°C, the dye impurities were removed in the same manner as in Comparative Example 7. Then, each polymer was separated from the polymer material of the blended material by selective dissolution of polyurethane and its properties were analyzed.

[0203] Example 14

[0204] When removing dye impurities from the colored blended material fibers of raw material 4, except that the temperature of the anisole used as the first compound was maintained at 150°C, the dye impurities were removed in the same manner as in Comparative Example 7. Then, each polymer was separated from the polymer material of the blended material by selective dissolution of polyurethane and its properties were analyzed.

[0205] Example 15

[0206] Except that raw material 5, which is doped with red dye, was used instead of raw material 4 in the fiber as a colored blend material, and the temperature of the anisole used as the first compound was maintained at 150°C when removing dye impurities, the dye impurities were removed in the same way as in Comparative Example 7. Then, each polymer was separated from the polymer material of the blend material by selective dissolution of polyurethane and its properties were analyzed.

[0207] Comparative Example 8

[0208] Except that raw material 5, which is doped with red dye, was used instead of raw material 4 in the fiber used as a colored blend material, and the temperature of the anisole used as the first compound was maintained at 190°C when removing dye impurities, the dye impurities were removed in the same manner as in Comparative Example 7. Then, each polymer was separated from the polymer material of the blend material by selective dissolution of polyurethane and its properties were analyzed.

[0209] Table 5 records the color characteristics of fibers decolored by contact with the first compound. Figure 8 The photographs of the various fibers after decolorization are illustrated in the figure. It can be confirmed that partial decolorization occurred in Comparative Example 7, where the contact temperature with the first compound (anisole) was less than 100°C, but the K / S value was above 15, indicating a relatively high amount of dye residue. Selective dissolution of polyurethane was achieved by adding the second compound to the mixed polymer material containing the first compound, and dark impurities remained in the filtrate during filtration for separation from the polyester, which significantly affected the quality of the product obtained by subsequent depolymerization of the polyurethane.

[0210] Conversely, when decolorizing by contact with the first compound, maintaining the contact temperature above 100°C allows for effective decolorization. Furthermore, the addition of the second compound selectively dissolves the polyurethane, thereby obtaining a high-purity polymer as a depolymerization raw material. In Comparative Example 8, where decolorization was performed at excessively high temperatures, similar to Comparative Example 6 described above, where a mixed solvent consisting of the first and second compounds was maintained at 190°C and contacted with the polymer material, excessive color change (yellowing) was observed due to a significant increase in the deterioration and oxidation of the polyurethane.

[0211] Table 5

[0212] <Depolymerization reaction of mixed materials or polymers separated from them>

[0213] Example 16

[0214] (I) Depolymerization of Polyester: When separating the mixed material according to the method of Example 2, the polyurethane dissolved during the filtration process in step (c) was removed with the filtrate. Approximately 22.5 g of anisole (at a ratio of 4 moles of terephthalate monomer per mole in the polymer) and approximately 38.8 g of ethylene glycol (at a ratio of 12 moles of terephthalate monomer per mole in the polymer) were added to a three-necked flask, and then stirred with a magnetic stirrer after installing a reflux condenser at atmospheric pressure. When the reaction mixture reached the reflux temperature of the first compound (153°C), the catalytic reaction was initiated by adding approximately 0.20 g of potassium acetate catalyst. The reaction was carried out using a condenser with one end exposed to atmospheric pressure while maintaining the reaction temperature stably within ±1°C for 2 hours of continuous stirring. At the end of the reaction, a small amount of the reaction mixture was taken as a quantitative sample. The reaction yields of depolymerized monomers and dimers were determined using a high-performance liquid chromatograph (HPLC with a C18 column and a UV detector (λ=254nm)) calibrated with standard samples.

[0215] (ii) Analysis of depolymerization products: A methanol:water mixture of 70:30 (v / v) was used as the mobile phase for high-performance liquid chromatography (HPLC), and the total flow rate was maintained at 0.7 ml / min. For quantification, all reaction mixtures except for trace amounts of the sample were filtered through cellulose filter paper (pore size: 3 μm). Solid-phase compounds other than monomers, such as dimers, oligomers, and unreacted polymers, were obtained as solid components on the filter paper. The yields of the products within the reactants were calculated using the formula described below.

[0216] - Monomer yield, Y BHET (%) = M BHET / M0×100 (Formula 3)

[0217] - Yield of the dimer, Y Dimer (%) = M Dimer / M0×100 (Formula 4)

[0218] - Yield of oligomers, Y oligomer (%) = M oligomer / M0×100 (Formula 5)

[0219] - Yield of byproduct (MHET), Y MHET (%) = M MHET / M0×100 (Formula 6)

[0220] Among them, M BHET M Dimer M oligomer and M MHET M1 represents the number of moles of terephthalic acid ester functional groups in diethyl terephthalate (BHET), dimer, oligomer, and monoethyl terephthalate (MHET) obtained by high performance liquid chromatography (HPLC), while M0 represents the number of moles of repeating monomers in the polymer structure.

[0221] (iii) Recovery of depolymerization product: After adding 100 ml of distilled water to the depolymerization product, the reaction mixture containing the monomer was placed in a refrigerator at 4°C for 12 hours. Next, the crystallized solid phase was collected after removing a large amount of moisture using cellulose filter paper (pore size: 3 μm). The obtained solid component was then transferred to a vacuum dryer at 60°C for drying for at least 12 hours to obtain the monomer product.

[0222] In Example 16, a depolymerization reaction (alcoholization) was performed after further adding a catalyst and a reaction solvent to the polyester separated according to the method of Example 2 as described above. The product distribution of the depolymerization products obtained after a 2-hour reaction time during the depolymerization reaction of the separated polyester is shown in Table 6. Decomposition of the polyester fibers mainly occurred up to a 30-minute reaction time, while complete depolymerization was achieved after 2 hours, resulting in no unreacted polyester being detected. It is now known that the product yield after the alcoholysis reaction of polyester is determined by the reaction equilibrium between the monomer, bis(hydroxyethyl) terephthalate (BHET), and oligomers including dimers. It can be confirmed that the product yield values ​​obtained by the depolymerization reaction of the polyester separated from the mixed polymer material (Example 16) (Table 6) are highly similar to the product distribution obtained by the alcoholysis reaction of a single component (relatively pure polyethylene terephthalate (PET) sheets or polyester).

[0223] Table 6

[0224] The results of high-performance liquid chromatography (HPLC) analysis of the purity of the solid product obtained from the purification and recovery process of the depolymerization product in Example 16 (c) confirmed that a high-purity diethyl terephthalate (BHET) product with a purity of 99.2% was finally obtained.

[0225] Example 17

[0226] (I) Depolymerization of polyurethane: When separating the mixed material according to the method of Example 2, approximately 131g of the polyurethane-containing mixture separated into filtrate through the filtration process in (c) was added to a constant temperature bath filled with high-temperature methylphenyl silicone oil, which could be maintained at a certain temperature by means of a proportional-integral-derivative (PID) temperature controller. The mixture was stirred at 250 rpm until the temperature inside the reactor reached 150°C. After the temperature inside the reactor stabilized, the reaction was initiated by adding 0.2g of sodium hydroxide (KOH) as a catalyst. Total reflectance infrared spectroscopy (ATR / FT-IR; Bruker ALPHA II) was performed on the polyurethane of raw material 3, polytetrahydrofuran (PTHF) having the same structure as the polyol used to synthesize polyurethane (manufacturer: Sigma-Aldrich, number average molecular weight (Mn): ~2,000), and the regenerated polyol obtained by taking a portion of the reactants during the depolymerization process. The completion of depolymerization was determined by comparing the obtained spectra.

[0227] (ii) Recovery of reaction solvent

[0228] After the reaction was carried out by maintaining the temperature inside the reactor at 150°C for 2 hours, the reaction was terminated by separating the reactor from the oil thermostat. When the phase boundary region became clearly observable as the temperature dropped below 100°C, the unreacted ethylene glycol in the lower phase, along with most of the catalyst, was recovered using a separatory funnel. The organic compound separated into the upper phase was then transferred to a 100 ml evaporation flask of known empty weight for quantification.

[0229] (iii) Obtaining polyol products

[0230] A 100 ml evaporation flask containing the previously separated upper phase mixture was secured to a rotary evaporator and rotated at 150 rpm while in continuous contact with a water bath maintained at 65°C. The distillate was completely removed by evaporation under reduced pressure (10 torr) for approximately 1 hour. As a polyol product, 1 g of a pale yellow, highly viscous liquid residue remained in the rotary evaporator.

[0231] (iv) Characteristic analysis of polyol products

[0232] To analyze the bonding structure of the functional groups of the regenerated polyol finally produced according to the depolymerization and solvent separation process, Fourier transform infrared spectroscopy (FT-IR) analysis was performed on a portion of it after it was taken as an attenuated total reflectance (ATR) sample.

[0233] In addition, using nuclear magnetic resonance hydrogen spectroscopy (NMR) 1 1H-NMR was used to compare the structural properties of the polyol polymer (polytetrahydrofuran, PTHF) used in the synthesis of polyurethane and the regenerated polyol produced by depolymerization. 1 The H-NMR sample was prepared by uniformly mixing 30 mg of the sample into 0.7 ml of trifluoroacetic acid- d (Trifluoroacetic acid-) d TFA- d ) and dichloromethane- d 2(dichloromethane- d 2, CD2Cl2) is manufactured in a mixed solvent in a weight ratio of 1:10.

[0234] Example 18

[0235] Except that 15g of raw material 6 was used instead of raw material 1 as the colored mixed polymer material, the individual polymers were separated from the mixed polymer material by selective dissolution of polyurethane and their properties were analyzed, following the same method as in Example 2. When separating the mixed material according to the method of Example 2, approximately 13.3g of the polymer material remaining on the filter paper during filtration in (c) was used to carry out a depolymerization reaction according to the same method as in Example 16, thereby obtaining a depolymerized product containing the alcoholysis monomer (BHET, diethyl terephthalate).

[0236] During the filtration process following the reaction, solid compounds other than monomers, such as dimers, oligomers, and unreacted polymers, were recovered from the filter paper. Polypropylene, cotton, and nylon were also recovered simultaneously. The recovered polypropylene and cotton were nearly spherical in shape, similar to the initial form of raw material 6, and the recovered mass was approximately 3.7g, similar to the amount input.

[0237] Example 19

[0238] In Example 18, when separating the mixed material according to the method of Example 2, except that 0.2 g of potassium carbonate (K2CO3) was added as a catalyst to the filtrate containing polyurethane (approximately 131 g) separated by the filtration process in (c) to initiate the reaction instead of potassium hydroxide (KOH), the depolymerization reaction and analysis were carried out in the same manner as in Example 17. After removing the first and second compounds from the depolymerization product of the dissolved polyurethane, approximately 1.1 g of a light yellow recycled polyol product was obtained.

[0239] exist Figure 9 The diagram illustrates the structure and proton positions of the polyols that may be obtained during the depolymerization of polyurethane separated from the mixed polymer material of raw material 1. It also illustrates the general chemical structure of polytetrahydrofuran, the raw material for spandex, which is mainly used in blended fibers manufactured in a highly elastic manner in polyurethane.

[0240] Figure 10 The nuclear magnetic resonance (NMR) spectra of polyols obtained by depolymerizing polyurethane separated from mixed polymer materials (Examples 17 and 19) and polytetrahydrofuran (PTHF) reagents with a number average molecular weight of approximately 2,000 are 1H NMR spectra. 1The results were compared with those of H-NMR spectra. Highly similar spectra were observed, indicating that the polyol product obtained by depolymerization after separating polyurethane from the mixed polymer material has the same chemical structure as the raw material used to synthesize polyurethane, namely polytetrahydrofuran (PTHF).

[0241] Figure 11 The results are a comparison of infrared (IR) spectra obtained by attenuated total reflectance (ATR) analysis of a portion of the polyol products obtained by depolymerization prior to obtaining them (Examples 17 and 19) and polytetrahydrofuran (PTHF) supplied by the manufacturer. The polyol products obtained by depolymerization of polyurethane have characteristic peaks highly similar to those of polytetrahydrofuran (PTHF). Furthermore, weak characteristic peaks related to amine functional groups were observed in the products obtained by depolymerization of polyurethane. These peaks may represent urethane bonds that might be detected when trace amounts of amine impurities flow into the depolymerized product or when a portion of the oligomeric semi-finished product remains in the product due to incomplete decomposition of polyurethane. These trace impurities, even if removed or remaining during the synthesis of polyurethane, do not significantly affect the polymerization properties of the material during resynthesis.

[0242] <Separation and recycling of polyurethane and nylon from hybrid polymer materials>

[0243] Example 20 below illustrates an example of the process for separating and recycling polyurethane and nylon separately in a polymer material containing both nylon and polyurethane in a mixed material. Figure 2 The diagram illustrates the overall engineering process for separating polymer materials from a mixture, including the processes described above, and for the chemical reuse of depolymerizable polymers.

[0244] Example 20

[0245] Approximately 15g of a nylon (nylon 6)-polyurethane blend polymer material (raw material 7) was applied according to the method of Example 1, and dissolved in 70g of anisole (twice the amount used in Example 1) as the first compound. When applied to the heated mixture of the first and second compounds, not only the polyurethane but also the nylon was completely dissolved. Instead of filtering the solution containing the dissolved polyurethane and nylon at room temperature or simply by lowering the temperature as in step (c) of Example 1, a two-step filtration was performed. The solution containing the dissolved polyurethane and nylon was first filtered at a high temperature above 135°C. Unlike Example 18, maintaining a high temperature above 135°C during filtration resulted in all the solution passing through the filter paper. Next, the temperature of the filtrate was lowered by natural cooling, and nylon sedimentation occurred rapidly at a temperature below 130°C. After confirming that sedimentation no longer occurred, a second filtration was performed to separate the extract containing polyurethane and the solids containing nylon. Most of the dye was removed by washing the solids obtained in filter cake form with acetone, resulting in 11.3 g of nearly white nylon material. The mixture containing polyurethane was subjected to a depolymerization reaction in the same manner as in Example 17, yielding approximately 2.5 g of polyol as the final product.

[0246] exist Figure 12 The shapes of the polymer material of the nylon-polyurethane blend according to Example 20, as well as the intermediate and final products generated during the separation and recycling of each polymer according to the process of Example 20, are illustrated.

[0247] The separated polymers remained stable even after prolonged storage. A portion of the polyurethane-containing mixed solution obtained from the second filtration in Example 20 was taken, and the solvent was completely removed to obtain a high-viscosity substance, which was used as the polyurethane sample in the analysis. To observe the inflow of impurities or other polymer components within the separated polymers, Fourier transform infrared spectroscopy (FT-IR) and proton nuclear magnetic resonance spectroscopy (NMR) were performed on each product. 1 H-NMR analysis, the results are as follows: Figure 13 as well as Figure 15 As shown.

[0248] exist Figure 13In the Fourier transform infrared (FT-IR) spectrum of raw material 7, a mixed morphology of the characteristic peaks of nylon and polyurethane was observed. The spectra of the nylon and polyurethane separated into individual polymers exhibited patterns highly similar to the previously reported spectra and the spectra of polyurethane (or pure nylon) obtained in Example 2. However, it can be confirmed that due to the partial similarity in chemical structure between the two polymers, simply comparing their Fourier transform infrared (FT-IR) spectra is insufficient for quantitative analysis of the impurity content or contamination level within each polymer.

[0249] Figure 15 The proton nuclear magnetic resonance spectra were performed on the individual polymers separated by the selective dissolution process of raw material 7 and in Example 20. 1 The results were compared with those obtained by ¹H-NMR analysis. When comparing the spectra measured in raw material 7 and the separately separated polymer substances, unlike raw material 7, only distinct characteristic peaks representing the structures of each polymer were observed in the separated substances, and there were no overlapping characteristic peaks of other polymers. Furthermore, no peaks were detected simultaneously at any other location besides the solvent used for the determination, indicating that the polymers obtained through separation have high purity.

[0250] <Separation and depolymerization of single polymers from mixed polymer materials>

[0251] In Examples 21 to 27 below, examples are illustrated of how nylon or / and polyurethane are separated from a polymer material containing a mixture of nylon and / or polyurethane according to the method of Example 20, and the chemically recyclable polymer is depolymerized to produce recycled monomers or recycled raw materials.

[0252] Example 21

[0253] Except that raw material 8 was used in place of raw material 7, the residual polymer raw material obtained after separating the polyurethane by the same selective dissolution method as in Example 20, regardless of the presence of polyester, was exposed to depolymerization reaction conditions in the same manner as in Example 16. For each polymer product obtained, stereomicroscopy, Fourier transform infrared spectroscopy (FT-IR), and nuclear magnetic resonance spectroscopy (NMR) were used. 1 H-NMR was used to analyze the shape changes and compound structure of the polymer. Furthermore, for the separated mixture containing polyurethane, the depolymerization reaction was carried out using the same method as in Example 17.

[0254] Example 22

[0255] In addition to using raw material 9 instead of raw material 8, after separating the polyurethane by applying the same selective dissolution method as in Example 21, the individual isolates were depolymerized, and the individual products obtained were analyzed.

[0256] Example 23

[0257] In addition to using raw material 10 instead of raw material 8, after separating the polyurethane by applying the same selective dissolution method as in Example 21, the individual isolates were depolymerized, and the individual products obtained were analyzed.

[0258] Example 24

[0259] In addition to using raw material 11 instead of raw material 8, after separating the polyurethane by applying the same selective dissolution method as in Example 21, the individual isolates were depolymerized, and the individual products obtained were analyzed.

[0260] Example 25

[0261] In addition to using raw material 12 instead of raw material 8, after separating the polyurethane by applying the same selective dissolution method as in Example 21, the individual isolates were depolymerized, and the resulting products were analyzed.

[0262] Example 26

[0263] In addition to using raw material 13 instead of raw material 8, after separating polyurethane and nylon (nylon 6,6) by means of the same selective dissolution method as in Example 21, the separates were depolymerized and the resulting products were analyzed.

[0264] Example 27

[0265] In addition to using raw material 14 instead of raw material 8, after separating polyurethane and nylon by means of the same selective dissolution method as in Example 21, the separates were depolymerized and the resulting products were analyzed.

[0266] Through Examples 21 to 26, nylon and polyurethane can be separated with high purity through selective dissolution as in Example 20, while only polyester depolymerization occurs selectively during depolymerization of the residual polymer mixture. In the raw material compositions of these examples, fibers such as cotton, rayon, and Tencel do not dissolve in the mixed solvent composed of the first and second compounds, nor do they decompose through depolymerization (alcoholysis), thus being discharged in a solid phase while maintaining the polymer shape within the raw material.

[0267] exist Figure 16 The polymer obtained by selectively dissolving and depolymerizing fiber raw materials equivalent to raw materials 8 to 13 according to the methods of Examples 21 to 26 is illustrated in the figure. It is the result of magnified observation of the polymer after selective dissolution of nylon and polyurethane by selective dissolution with a mixed solvent composed of the first compound and the second compound, and the residual polymer obtained after exposure to the depolymerization conditions of polyester.

[0268] The polyurethane content of raw materials 8 to 10 is different. Depending on the initial polyurethane content, the elasticity after selective dissolution and the shape of the deformed polymer show significant differences. When raw material 8, containing a large amount of polyurethane, is used as the raw material (Example 21), the fibers with selectively removed urethane significantly lose elasticity, and large pores form in the urethane-removed portion. Conversely, when raw material 10, with a lower initial polyurethane content, is used (Example 22), even under selective dissolution and depolymerization conditions, because the polyurethane content in the raw material is low and it does not contain polyester, the fibers themselves do not undergo significant changes even when exposed to selective dissolution and depolymerization conditions.

[0269] When using raw material 11 (Example 24), as a fiber with the front and back sides made of different materials (each containing polyurethane, but the front side is made of cotton-urethane and the back side is made of polyester-urethane), it was confirmed that only a slight degree of deformation was observed when the polyurethane was extracted by selective dissolution. However, when the polymer with the polyurethane removed was applied to depolymerization conditions, the polyester completely decomposed, leaving only a substance with the same material (cotton) on both sides. This indicates that a polymer composed solely of cotton can ultimately be obtained.

[0270] When using raw material 12 (Example 25), other shapes of fiber structures were observed along with the removal of polyurethane. When the polyester was depolymerized by depolymerization, most of the polymers (polyurethane and polyester) that initially constituted the fibers were completely removed by selective dissolution and depolymerization, and only unreacted polymers (Tencel) in the form of loose long fibers were obtained.

[0271] When using raw material 13 (Example 26), after selectively dissolving and extracting polyurethane and nylon, a woven fabric made of polyester was obtained. Subsequently, when exposed to depolymerization conditions, all polymers decomposed without leaving any residue.

[0272] Example 27 is an example of using a polymer (raw material 14) that contains all the polymers included in the raw materials used in Examples 21 to 26, and further diversifies the composition by adding silk and acrylic fibers. As in the previous examples, nylon and polyurethane can be separated sequentially using a mixed solvent composed of the first and second compounds, and then depolymerization conditions can be applied to the residual polymer. The residual polymer compound contains all materials (cotton, rayon, and Tencel) that could not be separated or decomposed by selective dissolution and depolymerization in the previous examples, as well as the further added acrylic and silk fibers.

[0273] Figure 17 These are magnified photographs taken using a stereomicroscope, showing acrylic acid and silk fibers within raw material 14, as well as acrylic acid and silk fibers recovered from residual polymers, and illustrating the morphology of the residual fibers obtained after depolymerization. The acrylic fibers were supplied in a coarsely woven form, but during depolymerization, they became loosely entangled. In contrast, the silk retained fibers in almost the same form.

[0274] Using only the individual fibers (acrylic and silk) and measuring the ratio of the final fiber mass to the initial input mass, the result reached a level of over 95%. Considering that no erosion was observed in the polymer yarn itself, it can be inferred that this weight reduction is not due to a change in mass caused by the chemical decomposition of the polymer during selective dissolution or depolymerization, but rather equivalent to a physical loss occurring during the separation and depolymerization of the polymer. Therefore, it can be concluded that acrylic or silk fibers hardly dissolve in the mixed solvent composed of the first and second compounds, and will not exhibit reactivity in any subsequent depolymerization (alcoholysis) of the mixed polymer.

[0275] In the foregoing description, the embodiments illustrated in the accompanying drawings have been used to illustrate the present invention. However, these are merely exemplary embodiments, and those skilled in the art should understand that the invention can be implemented through various modifications and equivalent embodiments. Therefore, the scope of protection of the present invention should be defined by the appended claims.

Claims

1. A composition for selectively dissolving and separating polymers having urethane functional groups and / or polymers having amide functional groups from a polymer mixture, characterized in that: As a composition for selectively dissolving and separating polymers having urethane functional groups and / or polymers having amide functional groups from polymers of mixed materials The polymer in the hybrid material is a substance that is part or all of a polymer selected from polymers having urethane functional groups and polymers having amide functional groups, and one or more polymers selected from cotton, linen, artificial silk, silk, acrylic acid, polyethylene, polypropylene, and polymer materials having ester functional groups. The composition comprises: one or more first compounds selected from aromatic compounds having one or more alkoxy functional groups; and one or more second compounds selected from compounds having one or more alcohol functional groups.

2. The composition according to claim 1 for selectively dissolving and separating polymers having urethane functional groups and / or polymers having amide functional groups from polymers of mixed materials, characterized in that: The weight ratio of the first compound to the second compound is 0.01 to 100.

3. A method for selectively dissolving and separating polymers having urethane functional groups and / or polymers having amide functional groups from a polymer mixture, characterized in that: As a method for selectively dissolving and separating polymers having urethane functional groups and / or polymers having amide functional groups from a polymer blend, the polymer blend is a substance comprising part or all of one or more polymers selected from polymers having urethane functional groups and polymers having amide functional groups, and one or more polymers selected from cotton, linen, rayon, silk, acrylic acid, polyethylene, polypropylene, and polymer materials having ester functional groups. The polymer of the mixed material is brought into sequential or simultaneous contact with one or more first compounds selected from aromatic compounds having one or more alkoxy functional groups and one or more second compounds selected from compounds having one or more alcohol functional groups, thereby selectively dissolving polymers having urethane functional groups and / or polymers having amide functional groups from the polymer of the mixed material.

4. The method for selectively dissolving and separating polymers having urethane functional groups and / or polymers having amide functional groups from a polymer of mixed materials according to claim 3, characterized in that: When the polymer in the mixed material does not contain polymers with amide functional groups, the temperature range for selectively dissolving only polymers with urethane functional groups is 100 to 180°C.

5. The method for selectively dissolving and separating polymers having urethane functional groups and / or polymers having amide functional groups from a polymer of mixed materials according to claim 3, characterized in that: When both urethane functional groups and amide functional groups are present in the polymer of the mixed material, the temperature range for dissolving the polymers with urethane functional groups and amide functional groups is 135°C to 180°C.

6. The method for selectively dissolving and separating polymers having urethane functional groups and / or polymers having amide functional groups from a polymer of mixed materials according to claim 3, characterized in that: The sequential contact means first contacting the first compound, then contacting the second compound.

7. The method for selectively dissolving and separating polymers having urethane functional groups and / or polymers having amide functional groups from a polymer of mixed materials according to claim 3, characterized in that: The mass of the first compound relative to the polymer of the mixed material is in the range of 0.1 to 1000 times, and the weight ratio of the first compound to the second compound is in the range of 0.01 to 100.

8. A method for regenerating polymer materials with mixed materials, characterized in that: As a method for regenerating polymer materials as a composite material, The polymer of the hybrid material is a substance that comprises, as part or all of, a polymer selected from polymers having urethane functional groups and polymers having amide functional groups, and a polymer selected from cotton, linen, rayon, silk, acrylic acid, polyethylene, polypropylene, and polymer materials having ester functional groups. The regeneration method includes: (a) The step of contacting the polymer material of the mixed material with one or more first compounds selected from aromatic compounds having one or more alkoxy functional groups and one or more second compounds selected from compounds having one or more alcohol functional groups, thereby selectively dissolving only the polymers having urethane functional groups and / or polymers having amide functional groups in the mixed polymer material. (b) Filtering the mixed solution generated after the selective dissolution to separate polymers having urethane functional groups and / or polymers having amide functional groups from the polymer material of the mixed material; and (c) The depolymerization reaction step of depolymerizing the polymer separated in the solid phase.

9. The method for regenerating polymer materials with mixed materials according to claim 8, characterized in that: The polymer that is depolymerized in step (c) is a polymer with ester functional groups.

10. The method for regenerating polymer materials with mixed materials according to claim 9, characterized in that: Following step (c), the following is also included: (d) The step of separating the polymers with urethane functional groups by adjusting the temperature of the mixture containing both polymers with urethane functional groups and polymers with amide functional groups, so that only the polymers with amide functional groups settle; and the step of performing... The feature is that it further includes: (e) a depolymerization reaction step of depolymerizing the separated polymer having urethane functional groups.

11. The method for regenerating polymer materials with mixed materials according to claim 9, characterized in that: Following step (c), the process further includes a depolymerization reaction step of depolymerizing the isolated polymer having urethane functional groups.

12. The method for regenerating polymer materials of mixed materials according to claim 10 or claim 11, characterized in that: The depolymerization of the polymer having urethane functional groups is carried out by adding a catalyst for depolymerization of the polymer having urethane functional groups to the filtered filtrate.

13. The method for regenerating polymer materials with mixed materials according to claim 12, characterized in that: The polymer depolymerization catalyst having urethane functional groups is selected from one or more of the following groups: metal catalysts composed of alkali metal hydroxides, alkaline earth metal hydroxides, alkali metal acetates, alkaline earth metal acetates, alkali metal carbonates, alkali metal bicarbonates, alkaline earth metal carbonates, and alkali metal oxides; and organic compounds of guanidines or amines.

14. The method for regenerating polymer materials with mixed materials according to claim 11, characterized in that: The depolymerization of the polymer having urethane functional groups is carried out in a temperature range of 100 to 170°C.

15. The method for regenerating polymer materials with mixed materials according to claim 9, characterized in that: In step (c), the depolymerization of the polymer containing the ester functional group is carried out using one or more of the following methods: hydrolysis, glycolysis, methanolysis, ethanolysis, and ammonolysis.

16. The method for regenerating polymer materials with mixed materials according to claim 8, characterized in that: Substances that have not depolymerized in the polymer separated into a solid phase in step (c) are separated from the reaction products by filtration or centrifugation.

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