Method for selecting ester-functional polymers from mixtures of ester-functional polymers with other types of polymers

Abstract

The present invention relates to a method for separating an ester functional group-containing polymer from a polymer mixture containing an ester functional group-containing polymer and other types of polymers, and relates to a method for selectively removing and decolorizing a polymer mixture using an extractant that selectively extracts foreign matter that exhibits color only in the ester functional group-containing polymer, and then separating the decolorized polymer from other polymers that have not been decolorized by utilizing the color difference.

Description

[Technical field]

[0001] The present invention relates to a method for effectively separating an ester functional group-containing polymer from a polymer mixture in which an ester functional group-containing polymer is mixed with a different type of polymer, and more particularly, to a technology that enables a relatively simple and low-cost separation of an ester functional group-containing polymer from a polymer mixture through a method of removing only color-producing foreign substances contained in an ester functional group-containing colored polymer using a chemical extractant. [Background technology]

[0002] Synthetic polymers synthesized using raw materials extracted from petroleum are inexpensive and durable materials, and have the advantages of being easy to mold and process, and are used to produce a variety of products such as synthetic fibers and plastics. Due to these advantages, the consumption of products using synthetic polymers has increased dramatically in various areas of life for several decades. However, problems have arisen in that synthetic polymer waste that is not properly managed is left in the environment, causing environmental pollution, or is broken down into small fragments that float around the ecosystem and accumulate in organisms, eventually reentering the human body via fine dust, drinking water, food, etc.

[0003] In order to solve these problems, various research and efforts are being made to minimize the accumulation of plastics or reduce their environmental impact, including the development of new plastic substances with a short decomposition period in nature, from the chemical decomposition of existing petroleum-based plastics to the physical regeneration and reprocessing of plastics. Physical or physical recycling, which reuses polymer materials themselves or reuses them by changing only some of their characteristics, has limited applications because it is difficult to control their physical properties or quality. Chemical recycling technology, which depolymerizes waste synthetic polymer products discharged after use to produce monomers and uses them as polymerization raw materials to reproduce products of the same quality as the original materials, is attracting a lot of attention.

[0004] Since the depolymerization method of the synthetic polymer differs depending on the type of synthetic polymer, it is necessary to first classify waste polymer products, which are a mixture of various components, into a single substance having uniform polymer structure characteristics. In particular, in the case of waste textile products, this is even more necessary since waste textile products are often discharged in the form of a mixture of various types of fibers or in the form of a blended material.

[0005] Polymer products containing ester functional groups can be monomerized by depolymerization, and the monomers produced by decomposition can theoretically have the same properties as the raw materials input into the initial polymer synthesis. Depolymerization routes used industrially to recycle PET include hydrolysis, glycolysis, methanolysis, and ammonolysis, and various chemical depolymerization methods are used until a composite process is achieved that combines the advantages of each process.

[0006] Meanwhile, it is more common for polymer products to be used with color-producing substances such as dyes and pigments introduced for color expression, and these color-producing substances have a structure different from that of the polymer. The introduced color-producing substances remain even after the depolymerization of the polymer, and may affect the properties of the product, and are impurities that are difficult to remove, so it is preferable to remove these color-producing foreign substances before or after the depolymerization. As a color-producing foreign substance in a polymer, a dye has a very small particle size or a molecular form that is uniformly soluble in most solvents, and is used to dye fibers, leather, etc. through a coloring process. The dyes are classified into natural dyes obtained from plants, animals, or minerals, and artificial dyes that are artificially synthesized. Examples of artificial dyes include direct dyes, mordant dyes, reductive dyes, chromogenic dyes, disperse dyes, and reactive dyes. Dyes that are mainly applied to ester functional group-containing polymer materials are most typically azo-based and anthraquinone-based disperse dyes that can be classified according to their chemical structure.

[0007] The colored polymers containing ester functional groups as described above are known as waste resources that cause environmental problems because the colored dye molecules, which are color-producing foreign matter within the polymer, exist in the form of a complex with the polymer substrate, making it difficult to separate or remove the color-producing colored molecules by simple contact with water or an organic solvent. As a result, physical and chemical recycling is difficult, and most of the polymers are discarded or incinerated.

[0008] Therefore, it is necessary to develop a highly effective and economical separation technique for removing color-producing foreign matter from colored polymers containing ester functional groups. To achieve this, it is first necessary to separate the ester functional group-containing polymer from the discharged waste polymer mixture.

[0009] Existing classification methods for selecting polymers include physical separation methods that use differences in polymer density; spectroscopic classification methods that classify polymers according to their light absorption, diffusion, and reflection spectra due to their structure; and chemical classification methods that involve polymer decomposition, such as oxidation, reduction, hydrolysis, and electrolysis.

[0010] As prior art, International Publication No. WO2013 / 182801 discloses a method for separating fibers by utilizing the density difference between polyester and cotton, and China Publication No. CN104730004A and Autex Research Journal, 19(2), 201-209 (2019) disclose a method for identifying fibers by utilizing the difference in the diffuse reflectance spectrum of light due to the structure of the fiber. The methods of these prior documents have problems in that the measurement and classification methods applied for substance classification are highly influenced by the measurement environment or separation conditions, resulting in low accuracy, and various auxiliary equipment and complex processes are required to increase reliability, resulting in low utility value in terms of efficiency and cost. Summary of the Invention [Problem to be solved by the invention]

[0011] The present invention provides a method for separating an ester functional group-containing polymer from a colored polymer mixture, which contains an ester functional group-containing colored polymer and a different type of colored polymer, by selectively decolorizing only the ester functional group-containing polymer from the colored polymer mixture and separating the polymer from which color-producing foreign matter has been removed from the non-decolorized polymer by utilizing color differences, and an extractant for the selective decolorization.

[0012] The present invention also provides a method for separating all of the colorless and colored ester functional group-containing polymers from a molecular mixture in which the colorless and colored ester functional group-containing polymers are mixed. [Means for solving the problem]

[0013] In order to solve the above problems, the present invention provides an extractant for selectively eluting and removing foreign matter that exhibits color only in the ester functional group-containing polymer from a colored polymer mixture in which an ester functional group-containing colored polymer and a different type of colored polymer are mixed, the extractant comprising at least one of a compound represented by the following Chemical Formula 1 and a compound represented by the following Chemical Formula 2:

[0014] [ka]

[0015] In the above Chemical Formula 1, A 1 is selected from the group consisting of a carboxyl group, an aldehyde group, and a nitrile group; R 1 is any one selected from a hydroxyl group, a carboxyl group, an aldehyde group, a nitrile group, a linear or branched saturated hydrocarbon having 1 to 6 carbon atoms, a linear or branched unsaturated hydrocarbon having 1 to 6 carbon atoms, a cycloalkyl group having 4 to 6 carbon atoms, and an aryl group having 6 to 12 carbon atoms, and m is any integer selected from 0 to 5, and when m is 2 or more, R 1may be the same or different. n is an integer selected from 1 to 6. When n is 2 or more, A 1 may be the same or different from each other.

[0016] In addition, in the above-mentioned chemical formula 2, A 2 is at least one of an ester, an ether, and a carbonyl; R 2 is an alkyl group having 1 to 10 carbon atoms. n is an integer selected from 1 to 6, and when n is 2 or more, A 2 and R 2 may be the same or different. 1 The definitions of and m are the same as those of Chemical Formula 1.

[0017] In an embodiment of the present invention, the compound represented by Formula 1 or the compound represented by Formula 2 is 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, 1,2,4-triethoxybenzene, 1,3,5-triethoxybenzene, 1,2,3,4-trimethoxybenzene, 1,3,5-triethoxybenzene, 1,2,3,4-trimethoxybenzene, 1,3,5-triethoxybenzene, 1,2,3,4-trimethoxybenzene, 1,3,5-triethoxybenzene, 1,2,3,4-trimethoxybenzene, 1,3,5-triethoxybenzene, 1,3,5-triethoxybenzene, 1,3,5-triethoxybenzene, 1,3,5-trimethoxy ... Tetramethoxybenzene, 1,2,3,5-tetramethoxybenzene, 1,2,4,5-tetramethoxybenzene, 1-methoxy-2-methylbenzene, 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-methylbenzene Ethylbenzene, 1-methoxy-2-prop-2-enylbenzene, 1-methoxy-3-prop-1-enylbenzene, 1-methoxy-3-prop-2-enylbenzene, 1-methoxy-4-prop-2-enylbenzene, 1-methoxy-4-[(E)-prop-1-enyl]benzene(cis), 1-methoxy-4-[(E)-prop-1-enyl]benzene(trans), methyl benzoate, ethyl benzoate, butyl benzoate, propyl benzoate, methyl 2-ethoxybenzoate, methyl 3-ethoxybenzoate, methyl 4-ethoxybenzoate 2,3-Dimethoxybenzoic acid, 2,3-Dimethoxybenzoic acid, 2,4-Dimethoxybenzoic acid, 2,4-Dihydroxybenzoic acid, 2,5-Dimethoxy-4-methylbenzoic acid, 2,5-Dimethoxybenzoic acid, 2,5-Dihydroxybenzoic acid, 2,6-Dimethoxy-4-methylbenzoic acid, 2,6-Dimethoxybenzoic acid, 2,6-Dihydroxybenzoic acid, 2-Methoxybenzoic acid, 2-Ethoxy-3-ethylbenzoic acid, 2-Ethoxybenzoic acid, 2-Hydroxy-3-methoxybenzoic acid, 2-Hydroxy-4,5-dimethoxybenzoic acid, 2-Hydroxy-4,6-dimethoxybenzoic acid, 2-Hydroxy-4-methoxybenzoic acid, 2-Hydroxy-5-methoxybenzoic acid, 2-Hydroxy-6-methoxybenzoic acid, 2-Hydroxybenzoic acid, 3-(4-Hydroxy-3,5-dimethoxyphenyl)prop-2-ene Acid, 3,4-dimethoxybenzoic acid, 3,4-dihydroxybenzoic acid, 3,5-dimethoxy-4-methylbenzoic acid, 3,5-dimethoxybenzoic acid, 3-methoxybenzoic acid, 3-ethoxy-4-hydroxybenzoic acid, 3-ethoxy-5-ethylbenzoic acid, 3-ethoxybenzoic acid, 3-hydroxy-4,5-dimethoxybenzoic acid, 3-hydroxy-4-methoxybenzoic acid, 3-hydroxy-5-methoxybenzoic acid, 3-hydroxybenzoic acid, 4-methoxybenzoic acid, 4-ethoxy-2-ethyl Benzoic acid, 4-ethoxy-3-ethylbenzoic acid, 4-ethoxybenzoic acid, 4-hydroxy-2,6-dimethoxybenzoic acid, 4-hydroxy-2,6-dimethylbenzoic acid, 4-hydroxy-2-methoxybenzoic acid, 4-hydroxy-3,5-dimethoxybenzoic acid, 4-hydroxy-3,5-dimethylbenzoic acid, 4-hydroxy-3-methoxybenzoic acid, 4-hydroxybenzoic acid, ethyl 2-methoxybenzoic acid, ethyl 3-methoxybenzoic acid, ethyl 4-methoxybenzoic acid, 2,3-dimethyl 2-methoxyphenol, 2,4-dimethoxyphenol, 2,5-dimethoxyphenol, 2,6-dimethoxy-4-prop-2-enylphenol, 2,6-dimethoxyphenol, 2-[(E)-prop-1-enyl]phenol, 2-methoxy-4-(prop-1-enyl)phenol, 2-methoxy-4-prop-2-enylphenol, 2-methoxyphenol, 2-ethoxyphenol, 2-tert-butyl-4-methoxyphenol, 3,4-dimethoxyphenol, 3,5-Dimethoxyphenol, 3-Methoxyphenol, 3-Ethoxyphenol, 3-tert-Butyl-4-Methoxyphenol, 3-Prop-1-en-2-ylphenol, 4-(Prop-1-en-2-yl)phenol, 4-(Prop-2-en-1-yl)phenol, 4-Methoxy-2-[(E)-prop-1-enyl]phenol, 4-Methoxyphenol, 4-Ethoxyphenol, 4-Ethyl-2,3-dimethylphenol, 4-Ethyl-2,5-dimethoxyphenol, 4-Ethyl-2,6-dimethoxyphenol, 4-tert-butyl-4-methoxyphenol, t-Butyl-2-methoxyphenol, 1-(2-hydroxy-4,6-dimethylphenyl)ethanone, 1-(4-methoxyphenyl)ethanone, 1-(4-hydroxy-2,6-dimethoxyphenyl)ethanone, 1-(4-hydroxy-3,5-dimethoxyphenyl)ethanone, 1-(5-hydroxy-2,4-dimethylphenyl)ethanone, 1-phenylbutan-1-one, 1-phenylethanone, 1-phenylpropan-1-one, 2,3-dihydroxybenzaldehyde, 2,4-dihydroxybenzaldehyde, 2,5-dihydroxybenzaldehyde aldehyde, 2-methoxybenzaldehyde, 2-methylbenzaldehyde, 2-butoxybenzaldehyde, 2-ethoxybenzaldehyde, 2-hydroxy-3,5-dimethoxybenzaldehyde, 2-hydroxy-3-methoxybenzaldehyde, 2-hydroxy-4,6-dimethoxybenzaldehyde, 2-hydroxy-4-methoxybenzaldehyde, 2-hydroxy-5-methoxybenzaldehyde, 2-hydroxy-6-methoxybenzaldehyde, 2-hydroxybenzaldehyde, 3,4-dihydroxybenzaldehyde, 3,5-dihy hydroxybenzaldehyde, 3-methoxybenzaldehyde, 3-methylbenzaldehyde, 3-butoxybenzaldehyde, 3-ethoxy-2-hydroxybenzaldehyde, 3-ethoxybenzaldehyde, 3-hydroxy-2-methoxybenzaldehyde, 3-hydroxy-4-methoxybenzaldehyde, 3-hydroxy-5-methoxybenzaldehyde, 3-hydroxybenzaldehyde, 4-methoxybenzaldehyde, 4-methylbenzaldehyde, 4-butoxybenzaldehyde, 4-ethoxybenzaldehyde, 4-hydroxy-2,6-dimethoxybenzaldehyde, 4-hydroxy-2-methoxybenzaldehyde, 4-hydroxy-3,5-dimethoxybenzaldehyde, 4-hydroxy-3-methoxybenzaldehyde, 4-hydroxybenzaldehyde, benzaldehyde, 2,3-dihydroxybenzonitrile, 2,4-dihydroxybenzonitrile, 2,5-dihydroxybenzonitrile, 2,6-dihydroxybenzonitrile, 2-methoxybenzonitrile, 2-methylbenzonitrile, 2-hydroxybenzonitrile, 3,4-dihydroxybenzonitrile, 3-methoxybenzonitrile, 3-methylbenzonitrile, 3-hydroxybenzonitrile, 4-methoxybenzonitrile, 4-methylbenzonitrile, 4-acetylbenzonitrile, 4-hydroxybenzonitrile, benzonitrile, etc. It may be characterized as being one or more selected from the group consisting of.

[0018] The present invention also provides a method for separating an ester functional group-containing polymer from a colored polymer mixture in which an ester functional group-containing colored polymer and a different type of colored polymer are mixed, the method comprising the steps of: (a) contacting the polymer mixture in which an ester functional group-containing colored polymer and a different type of colored polymer are mixed with an extractant that extracts color-producing foreign matter to selectively decolorize the ester functional group-containing colored polymer; and (b) separating the decolorized polymer from the non-decolorized polymer in the step (a) by utilizing the difference in color between the polymer and the non-decolorized polymer.

[0019] In one embodiment of the present invention, the ester functional group-containing polymer is in the form of a fiber or a fabric, and the fabric may be a single ester functional group-containing polyester fiber, or a blended fabric containing an ester functional group-containing polyester fiber and at least one of polyethylene, polypropylene, polystyrene, polyvinyl chloride, cotton, linen, wool, rayon, acetate, acrylic, nylon, and spandex.

[0020] In one embodiment of the present invention, the colored polymer is a polymer that is colored by a foreign substance that exhibits one or more colors, and the polymer mixture includes color space coordinates (L * a * b * ) into two-dimensional (or planar) coordinates (L * X * ), the coordinate value L * is 60 or more, X * Polymers that satisfy the formula of 50 or less may be excluded. * is a * and b * This shows the square root of the sum of the squares of the values.

[0021] In another embodiment of the present invention, the decolorization process of step (a) may be performed in the range of 70 to 200°C.

[0022] In one embodiment of the present invention, the color space coordinates (L * a * b * ) into two-dimensional (or planar) coordinates (L * X * ), the coordinate value L * is 60 or more, X * can be characterized in that it satisfies 50 or less.

[0023] The present invention also provides a method for separating a polymer mixture containing a colorless ester functional group-containing polymer, the method comprising the steps of: (i) contacting a polymer mixture containing an ester functional group-containing polymer and a different type of polymer with a color-producing foreign matter to selectively stain only the ester functional group-containing polymer; (ii) excluding the colorless polymer from the polymer mixture by utilizing the color difference in the mixture after step (i); (iii) contacting the mixture after step (ii) with an extractant that extracts the color-producing foreign matter to selectively decolorize only the colored polymer containing the ester functional group; and (iv) separating the decolorized polymer from the non-decolorized polymer by utilizing the color difference.

[0024] In another embodiment of the present invention, the extractant in step (iii) may include one or more of the compound represented by Chemical Formula 1 and the compound represented by Chemical Formula 2.

[0025] In another embodiment of the present invention, in the step (ii), the color space coordinates (L * a * b * ) to two-dimensional coordinates (L * X * ), the coordinate value L * is 60 or more, X * is 50 or less, and the color space coordinates (L * a * b * ) to two-dimensional coordinates (L * X * ), the coordinate value L * is 60 or more, X * can select items that satisfy the criteria of 50 or less.

[0026] In another embodiment of the present invention, the dyeing in step (i) can be carried out by recovering and using a waste extractant mixed with the color-producing foreign matter obtained in the decolorization in step (iii). Effect of the Invention

[0027] In the present invention, by removing foreign matter that selectively exhibits color only in the ester functional group-containing polymer from a polymer mixture in which an ester functional group-containing polymer and a different type of polymer are mixed, the present invention has the effect of easily selecting the ester functional group-containing polymer from the polymer mixture by utilizing the color difference between the decolorized ester functional group-containing polymer and the other types of colored polymers that have not been decolorized.

[0028] In addition, the extractant according to the present invention is a solvent that is less harmful to the human body and does not cause serious physical / chemical changes to polymers other than those containing ester functional groups. It selectively acts only on polymers containing ester functional groups to rapidly elute colored substances at a relatively low temperature, making the decolorization process simple, economical, and environmentally friendly.

[0029] In addition, the waste extractant used in the decolorization process according to the present invention is recovered and reused in the initial dyeing process according to the present invention, thereby minimizing the generation of waste liquid in the process itself and improving process economy. [Brief description of the drawings]

[0030] [Figure 1] 1 shows the effect of the extractant according to one embodiment of the present invention, which shows the fibers decolorized by directly contacting each colored fiber with anisole as the extractant. [Diagram 2] 1 shows a comparison of color space coordinates (L*a*b*) of a fiber before and after bleaching treatment in two-dimensional coordinates (L*X*) according to an embodiment of the present invention. [Diagram 3] 1 shows the spectrum of a polyester fiber bleached according to an embodiment of the present invention, and shows a comparison of the spectrum according to the color of the fiber. [Figure 4] FIG. 1 shows a comparison of the decolorization effect of the indigo polyester fiber of raw material 2 by contact with the solvent and the color of the fiber after the solvent treatment when the decolorization process is performed using the solvents corresponding to Chemical Formula 1 and Chemical Formula 2 according to the present invention and the solvents not corresponding to the solvents as extractants. [Diagram 5] This shows the experimental results of a comparative example of the present invention, and illustrates the decolorization effect of the indigo polyester fiber of raw material 2 upon contact with a solvent in two-dimensional coordinates (L*X*). [Figure 6] 1 shows 13C NMR spectra for mixtures of ester functional group-containing polymers and the extractant of the present invention at different concentrations. [Figure 7] 1 shows 13C NMR spectra for various concentrations of mixtures of ester functional group-containing polymers and extractants not according to the present invention. [Figure 8] 1 shows 1H NMR spectra for mixtures of ester functional group-containing polymers and the extractant of the present invention at different concentrations. [Figure 9] 1 shows 1H NMR spectra for mixtures of varying concentrations of ester functional group-containing polymer and other forms of extractant not according to the present invention. [Figure 10] This shows the experimental results of a comparative example of the present invention, and compares the decolorization effect of the indigo polyester fiber of raw material 2 by contact with morpholine. [Figure 11] This paper shows the decolorization effect of 1-methylpyrrolidin-2-one and methylsulfinylmethane as extractants on ester functional group-containing polymers and other colored fibers. [Figure 12] Photographs of a colored fiber mixture before and after treatment with an extractant using a Soxhlet extractor and a photograph showing only the decolorized fibers in isolation. [Figure 13] 1 shows a spectrum of a fiber that satisfies reference coordinate values ​​among fibers decolorized using a Soxhlet extractor according to an embodiment of the present invention. [Figure 14]The optical spectra of colored fibers other than those containing ester functional groups and colorless fibers are shown together, and the optical spectra of the fibers are compared. [Figure 15] 1 is a photograph of fibers dyed according to an embodiment of the present invention and a comparative example. [Figure 16] 1 shows color space coordinates (L*a*b*) of fibers dyed according to an embodiment of the present invention and a comparative example, in two-dimensional coordinates (L*X*). [Figure 17] 1 shows color space coordinates (L*a*b*) of fibers dyed according to an embodiment of the present invention and a comparative example, in two-dimensional coordinates (L*X*). [Figure 18] FIG. 13 is a diagram showing the color change of a fiber when it is re-dyed with a waste extractant solution generated during the decolorization process and then decolorized again according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0031] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Generally, the nomenclature used herein is one that is well known and commonly used in the art.

[0032] Throughout this specification, when a part "comprises" a certain element, this means that it may further include other elements, rather than excluding other elements, unless specifically stated to the contrary.

[0033] In addition, throughout this specification, a colorless polymer refers to a polymer that does not have a color because it does not contain color-producing foreign matter, and is white or transparent in color, and a colored polymer refers to a polymer that contains color-producing foreign matter and has a color other than white.

[0034] Hereinafter, a method for selecting and separating only the ester functional group-containing colored polymer from a colored polymer mixture in which the ester functional group-containing colored polymer according to the present invention and a different type of colored polymer are mixed will be described in detail.

[0035] The method includes the steps of: (a) contacting a colored polymer mixture, in which an ester functional group-containing colored polymer and a different type of colored polymer are mixed, with an extractant containing at least one of a compound represented by the following formula 1 and a compound represented by the following formula 2, to decolorize only the ester functional group-containing colored polymer; and (b) separating the decolorized polymer from the non-decolorized polymer in the step (a) by utilizing the difference in color.

[0036] [ka]

[0037] In the above Chemical Formula 1, A 1 is selected from the group consisting of a carboxyl group, an aldehyde group, and a nitrile group; R 1 is any one selected from a hydroxy group, an ether group, an aldehyde group, a carboxyl group, a nitrile group, a linear or branched saturated hydrocarbon having 1 to 6 carbon atoms, a linear or branched unsaturated hydrocarbon having 1 to 6 carbon atoms, a cycloalkyl group having 4 to 6 carbon atoms, and an aryl group having 6 to 12 carbon atoms, and m is any integer selected from 0 to 5, and when m is 2 or more, R 1 may be the same or different. n is an integer selected from 1 to 6. When n is 2 or more, A 1 may be the same or different from each other.

[0038] In addition, in the above-mentioned chemical formula 2, A 2 may be selected from at least one of ester, ether and carbonyl; R 2 is an alkyl group having 1 to 10 carbon atoms. n is an integer selected from 1 to 6, and when n is 2 or more, A2 and R 2 may be the same or different. 1 The definitions of and m are the same as those of Chemical Formula 1.

[0039] The extractant in step (a) contains at least one of the compounds represented by Chemical Formula 1 and Chemical Formula 2, and is characterized in that at least one functional group is linked to an aromatic ring via a linker, and the functional group causes π-π interaction with an ester functional group-containing polymer or has hydrogen bonding power.

[0040] The extractant according to the present invention selectively removes color-producing substances only from the colored polymer containing ester functional groups in a mixture of various types of polymers, and does not have a significant effect on the color and shape of other different types of polymers, so that it is possible to selectively remove color-producing foreign substances from the colored polymer containing ester functional groups in a mixture of various types of polymers, thereby decolorizing the mixture.

[0041] Examples of the compound represented by Formula 1 or Formula 2 of the present invention include, but are not limited to, 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, 1,2,4-triethoxybenzene, 1,3,5-triethoxybenzene, 1,2,3 ,4-tetramethoxybenzene, 1,2,3,5-tetramethoxybenzene, 1,2,4,5-tetramethoxybenzene, 1-methoxy-2-methylbenzene, 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-prop-2-enylbenzene, 1-methoxy-3-prop-1-enylbenzene, 1-methoxy-3-prop-2-enylbenzene, 1-methoxy-4-prop-2-enylbenzene, 1-methoxy-4-[(E)-prop-1-enyl]benzene(cis), 1-methoxy-4-[(E)-prop-1-enyl]benzene(trans), methyl benzoate, ethyl benzoate, butyl benzoate, propyl benzoate, methyl 2-ethoxybenzoate, methyl 3-ethoxybenzoate, methyl 4-ethoxybenzoate 2,3-Dimethoxybenzoate, Ethyl 2-ethoxybenzoate, Ethyl 3-ethoxybenzoate, Ethyl 4-ethoxybenzoate, Ethyl (E) 3-(4-hydroxy-3,5-dimethoxyphenyl)prop-2-enoate, 2,3-dimethoxy-4-methylbenzoic acid, 2,3-dimethoxybenzoic acid, 2,4-dimethoxybenzoic acid, 2,4-dihydroxybenzoic acid, 2,5-dimethoxy-4-methylbenzoic acid, 2,5-dimethoxybenzoic acid, 2,5-dihydroxybenzoic acid, 2,6-dimethoxy-4-methylbenzoic acid, 2,6-dimethoxybenzoic acid, 2,6-Dihydroxybenzoic acid, 2-Methoxybenzoic acid, 2-Ethoxy-3-ethylbenzoic acid, 2-Ethoxybenzoic acid, 2-Hydroxy-3-methoxybenzoic acid, 2-Hydroxy-4,5-dimethoxybenzoic acid, 2-Hydroxy-4,6-dimethoxybenzoic acid, 2-Hydroxy-4-methoxybenzoic acid, 2-Hydroxy-5-methoxybenzoic acid, 2-Hydroxy-6-methoxybenzoic acid, 2-Hydroxybenzoic acid, 3-(4-Hydroxy-3,5-dimethoxyphenyl)prop-2-ene Acid, 3,4-dimethoxybenzoic acid, 3,4-dihydroxybenzoic acid, 3,5-dimethoxy-4-methylbenzoic acid, 3,5-dimethoxybenzoic acid, 3-methoxybenzoic acid, 3-ethoxy-4-hydroxybenzoic acid, 3-ethoxy-5-ethylbenzoic acid, 3-ethoxybenzoic acid, 3-hydroxy-4,5-dimethoxybenzoic acid, 3-hydroxy-4-methoxybenzoic acid, 3-hydroxy-5-methoxybenzoic acid, 3-hydroxybenzoic acid, 4-methoxybenzoic acid, 4-ethoxy-2-ethyl Benzoic acid, 4-ethoxy-3-ethylbenzoic acid, 4-ethoxybenzoic acid, 4-hydroxy-2,6-dimethoxybenzoic acid, 4-hydroxy-2,6-dimethylbenzoic acid, 4-hydroxy-2-methoxybenzoic acid, 4-hydroxy-3,5-dimethoxybenzoic acid, 4-hydroxy-3,5-dimethylbenzoic acid, 4-hydroxy-3-methoxybenzoic acid, 4-hydroxybenzoic acid, ethyl 2-methoxybenzoic acid, ethyl 3-methoxybenzoic acid, ethyl 4-methoxybenzoic acid, 2,3-dimethyl 2-methoxyphenol, 2,4-dimethoxyphenol, 2,5-dimethoxyphenol, 2,6-dimethoxy-4-prop-2-enylphenol, 2,6-dimethoxyphenol, 2-[(E)-prop-1-enyl]phenol, 2-methoxy-4-(prop-1-enyl)phenol, 2-methoxy-4-prop-2-enylphenol, 2-methoxyphenol, 2-ethoxyphenol, 2-tert-butyl-4-methoxyphenol, 3,4-dimethoxyphenol, 3,5-Dimethoxyphenol, 3-Methoxyphenol, 3-Ethoxyphenol, 3-tert-Butyl-4-Methoxyphenol, 3-Prop-1-en-2-ylphenol, 4-(Prop-1-en-2-yl)phenol, 4-(Prop-2-en-1-yl)phenol, 4-Methoxy-2-[(E)-prop-1-enyl]phenol, 4-Methoxyphenol, 4-Ethoxyphenol, 4-Ethyl-2,3-dimethylphenol, 4-Ethyl-2,5-dimethoxyphenol, 4-Ethyl-2,6-dimethoxyphenol, 4-tert-butyl-4-methoxyphenol, t-Butyl-2-methoxyphenol, 1-(2-hydroxy-4,6-dimethylphenyl)ethanone, 1-(4-methoxyphenyl)ethanone, 1-(4-hydroxy-2,6-dimethoxyphenyl)ethanone, 1-(4-hydroxy-3,5-dimethoxyphenyl)ethanone, 1-(5-hydroxy-2,4-dimethylphenyl)ethanone, 1-phenylbutan-1-one, 1-phenylethanone, 1-phenylpropan-1-one, 2,3-dihydroxybenzaldehyde, 2,4-dihydroxybenzaldehyde, 2,5-dihydroxybenzaldehyde aldehyde, 2-methoxybenzaldehyde, 2-methylbenzaldehyde, 2-butoxybenzaldehyde, 2-ethoxybenzaldehyde, 2-hydroxy-3,5-dimethoxybenzaldehyde, 2-hydroxy-3-methoxybenzaldehyde, 2-hydroxy-4,6-dimethoxybenzaldehyde, 2-hydroxy-4-methoxybenzaldehyde, 2-hydroxy-5-methoxybenzaldehyde, 2-hydroxy-6-methoxybenzaldehyde, 2-hydroxybenzaldehyde, 3,4-dihydroxybenzaldehyde, 3,5-dihy hydroxybenzaldehyde, 3-methoxybenzaldehyde, 3-methylbenzaldehyde, 3-butoxybenzaldehyde, 3-ethoxy-2-hydroxybenzaldehyde, 3-ethoxybenzaldehyde, 3-hydroxy-2-methoxybenzaldehyde, 3-hydroxy-4-methoxybenzaldehyde, 3-hydroxy-5-methoxybenzaldehyde, 3-hydroxybenzaldehyde, 4-methoxybenzaldehyde, 4-methylbenzaldehyde, 4-butoxybenzaldehyde, 4-ethoxybenzaldehyde, 4-hydroxy-2,6-dimethoxybenzaldehyde, 4-hydroxy-2-methoxybenzaldehyde, 4-hydroxy-3,5-dimethoxybenzaldehyde, 4-hydroxy-3-methoxybenzaldehyde, 4-hydroxybenzaldehyde, benzaldehyde, 2,3-dihydroxybenzonitrile, 2,4-dihydroxybenzonitrile, 2,5-dihydroxybenzonitrile, 2,6-dihydroxybenzonitrile, 2-methoxybenzonitrile, 2-methylbenzonitrile, 2-hydroxybenzonitrile, 3,4-dihydroxybenzonitrile, 3-methoxybenzonitrile, 3-methylbenzonitrile, 3-hydroxybenzonitrile, 4-methoxybenzonitrile, 4-methylbenzonitrile, 4-acetylbenzonitrile, 4-hydroxybenzonitrile, benzonitrile, etc. may be one or more selected from the group consisting of.

[0042] In addition, as an extractant for removing color-producing foreign matters from the colored ester functional group-containing polymer according to the present invention, among the compounds represented by Chemical Formula 1 and Chemical Formula 2, those having a melting point lower than the extraction temperature and existing in a liquid state can be used, and those having low viscosity and fluidity so that the diffusion of the color-producing foreign matters can occur quickly are preferred.

[0043] The ester functional group-containing polymer may be a polymer formed by condensation polymerization of a dicarboxylic acid and a dialcohol, wherein the dicarboxylic acid is selected from the group consisting of terephthalic acid, naphthalenedicarboxylic acid, diphenyldicarboxylic acid, diphenyletherdicarboxylic acid, diphenylsulfonedicarboxylic acid, diphenoxyethanedicarboxylic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, decanedicarboxylic acid, cyclohexanedicarboxylic acid, trimellitic acid, pyromellitic acid, and combinations thereof, and the dialcohol is selected from the group consisting of ethylene glycol, trimethylene glycol, 1,2-propanediol, tetramethylene glycol, tetramethylol ... and combinations thereof.

[0044] For example, the colored polymer containing ester functional groups can be selected from polyethylene terephthalate (PET), polypropylene terephthalate (PPT), polyglycolide or polyglycolic acid (PGA), polylactic acid (PLA), polycaprolactone (PCL), polyhydroxyalkanoate (PHA), polyhydroxybutyric acid (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.

[0045] The most common example of such ester-functional colored polymers is polyethylene terephthalate, where the starting materials for the preparation of the polymer are terephthalic acid or its derived monomers, and ethylene glycol.

[0046] The ester functional group-containing polymer may be used alone or in the form of a mixed resin mixed with a polymer other than the ester functional group-containing polymer, for example, a mixed polymer further containing one or more of plastic materials such as polyethylene, high density polyethylene, low density polyethylene, polypropylene, polystyrene, polyvinyl chloride, etc., and polymers such as cotton, hemp, wool, rayon, acetate, acrylic, nylon, spandex, etc. For reference, the other polymers to be mixed with the polyester functional group-containing polymer listed above as examples are merely examples and are not limited to those listed above.

[0047] The ester functional group-containing polymer may be in the form of all or a part of a material molded into a film, a bottle, or the like, or may be in the form of staple, filament, or a mixture thereof that is utilized for clothing or industrial purposes, or may be in the form of a raw thread, an amorphous body, or a woven fabric.

[0048] In the step (a), an extractant is directly contacted with the colored polymer mixture to dissolve and remove impurities that exhibit color only in the ester functional group-containing polymer from the mixture. The decolorization process in the step (a) can be repeated two or more times.

[0049] The step (a) can be carried out at 70 to 200° C., and more preferably at 120 to 150° C. If the temperature is less than 70° C., the dissolution rate is slow and the extraction effect may be limited, whereas if the temperature exceeds 200° C., the energy consumption may be very high.

[0050] In addition, the step (a) may be a method of effectively removing color-producing foreign matters by continuously refluxing the extraction mixture containing the color-producing foreign matters by heating the extraction mixture containing the color-producing foreign matters and condensing and cooling the vaporized extractant, which is then re-supplied, so that the liquid extractant is continuously contacted with the ester functional group-containing polymer.

[0051] In order to reflux only the extractant in the extraction mixture solution containing the color-producing foreign matter, the temperature of the heating section can be maintained at a temperature close to the boiling point of the extractant. The contact temperature between the polymer and the extractant (or the extraction temperature) can be determined depending on the amount of heat applied to the heating section and the reflux speed of the extractant, which can also affect the extraction performance. It may be preferable to perform the extraction so that the contact temperature between the polymer and the extractant is maintained at a temperature about 0 to 50°C lower than the boiling point of the extractant.

[0052] After the color-producing foreign matter is eluted from the ester functional group-containing colored polymer using the extractant, the extractant can be recovered from the extraction mixture containing the extractant and the color-producing foreign matter by at least one of evaporation and distillation.

[0053] The step (b) is a step of classifying the decolorized polymer from the non-decolorized polymer based on the color difference. In order to detect the color difference, not only a spectrophotometer but also a detector capable of simply distinguishing that the dye has been removed based on the color brightness or saturation can be used, and color coordinate values ​​such as RGB, HSV, CMYK, or Lab can be used.

[0054] It is more preferable that the color coordinate values ​​used to distinguish whether the material is bleached or not are based on a total reflection (SCI) measurement method including both specular light and diffuse light.

[0055] In this case, a process for detecting and automatically selecting the decolorized polymer can be configured according to the measured value and a criterion for determining whether or not decolorization has occurred. As described above, when the extractant of Formula 1 and / or Formula 2 according to the present invention is applied to a polymer mixture, decolorization occurs only in the polymer containing an ester functional group, so that only the polymer containing an ester functional group can be selectively selected.

[0056] The selected polymer can also be used in the recycling industry because it is decolorized by removing color-producing foreign substances (e.g., dyes) that are difficult to purify during the process of selecting only polymer resins containing high concentrations of ester functional groups from waste mixed polymer resins. For example, if the selected decolorized polymer is applied to the depolymerization reaction process of polymers containing ester functional groups, high-quality monomers can be produced without a costly purification process.

[0057] In another embodiment of the present invention, when a polymer mixture contains a colorless ester functional group-containing polymer, the selective decolorization method for the ester functional group-containing polymer can be applied to the colorless polymer by adding a process of dyeing the ester functional group-containing polymer as a method for selecting the colorless polymer.

[0058] This method is characterized by comprising the steps of: (i) contacting a polymer mixture containing an ester functional group-containing polymer and a different type of polymer with a color-producing foreign substance to selectively stain only the ester functional group-containing polymer; (ii) utilizing the color difference in the mixture after step (i) to remove colorless polymers from the polymer mixture; (iii) contacting the mixture after step (ii) with an extractant that extracts the color-producing foreign substance to selectively decolorize only the ester functional group-containing colored polymer; and (iv) separating the decolorized polymer from the undecolorized polymer by utilizing the color difference.

[0059] The step (i) is a step of contacting a polymer resin mixture containing a colorless polymer resin containing an ester functional group that does not take on a color with a disperse dye, etc., to dye the colorless polymer containing an ester functional group and convert it into a colored polymer. In this case, the dye must be a dye that selectively colors only the polymer containing an ester functional group, and may be, for example, an azo-based or anthraquinone-based disperse dye. The dye for coloring may be a new dye that has not been used, or may be a waste dye that has already been extracted from the colored polymer fiber containing an ester functional group by the extractant of the present invention.

[0060] The step (ii) is a step of excluding colorless polymers contained in the polymer resin mixture. Since the colorless polymers containing ester functional groups contained in the polymer mixture in the step (i) are colored, there are no colorless polymers containing ester functional groups in the step (ii), but there may be colorless polymers that do not contain ester functional groups. Therefore, the colorless polymers are excluded in the step (ii) by utilizing the color difference, so that only colored polymers are added to the step (iii).

[0061] Then, in step (iii), one or more of the extractants represented by Formula 1 and / or Formula 2 are used to selectively decolorize only the colored polymers containing ester functional groups in the polymer mixture. In step (iv), the polymers from which the dye has been removed are sorted based on their color differences, whereby only the polymers containing ester functional groups can be selectively classified from a mixture of various types of polymers.

[0062] The process of the present invention will be described in detail below through examples, comparative examples and experimental examples, which are representative examples according to the present invention and are not intended to limit the scope of the present invention.

[0063] Polymer raw materials containing ester functional groups raw material 1 A plain polyester fiber fabric that had not been dyed was cut to prepare a colorless polymer raw material having a square shape with one side measuring approximately 3 cm.

[0064] raw material 2 A plain polyester fiber fabric (dye weight ratio: 1.5% owf) dyed indigo blue using a disperse dye (dye: Dystar Dianix Blue ER 150%; CI Disperse Blue 56) was cut into pieces approximately 3 cm square on one side and prepared as a colored polymer raw material.

[0065] raw material 3 A plain polyester fiber fabric (dye weight ratio: 1.5% owf) dyed red using an azo disperse dye (CI Disperse Red 1) was cut and prepared as a colored polymer raw material with a square of approximately 3 cm on one side.

[0066] raw material 4 A plain polyester fiber fabric (dye weight ratio: 1.5% owf) dyed red using an anthraquinone disperse dye (CI Disperse Red 9) was cut and prepared as a colored polymer raw material with a square of approximately 3 cm on one side.

[0067] raw material 5 A blend of 82% polyester fiber and 18% spandex was dyed black using a disperse dye (dye: Dystar Dianix Deep Black Plus) (dye weight ratio: 1.5% owf) and cut into pieces to prepare a colored polymer raw material with a square shape of approximately 3 cm on one side.

[0068] Raw materials other than polymers containing ester functional groups raw material 6 An undyed plain nylon fiber fabric was cut to prepare a colorless polymer raw material having a square shape with one side measuring approximately 3 cm.

[0069] raw material 7 A plain nylon fiber fabric (dye weight ratio: 1.5% owf) dyed orange using an acid dye (dye: Dystar Telon Orange AGT 01; CI Acid Orange 116) was cut into pieces approximately 3 cm square on one side to prepare a colored polymer raw material.

[0070] raw material 8 An undyed plain wool fiber fabric was cut and prepared as a colorless polymer raw material having a square shape of about 3 cm on one side.

[0071] raw material 9 A plain wool fiber fabric (dye weight ratio: 1.5% owf) dyed orange using an acid dye (dye: Dystar Telon Orange AGT 01; CI Acid Orange 116) was cut into pieces approximately 3 cm square on one side to prepare a colored polymer raw material.

[0072] raw material 10 Undyed plain silk fiber fabric was cut and prepared as a colorless polymer raw material having a square shape of about 3 cm on one side.

[0073] raw material 11 Plain silk fiber fabric (dye weight ratio: 1.5% owf) dyed orange using an acid dye (dye: Dystar Telon Orange AGT 01; CI Acid Orange 116) was cut into pieces with a square shape measuring approximately 3 cm on one side, and prepared as a colored polymer raw material.

[0074] raw material 12 An undyed plain acrylic fiber fabric was cut and prepared as a colorless polymer raw material having a square shape of about 3 cm on one side.

[0075] raw material 13 A plain acrylic fiber fabric (dye weight ratio: 1.5% owf) that had been dyed yellow using a basic dye (Dystar Astrazon Golden Yellow GL-E 200%; CI Basic Yellow 28) was cut into pieces approximately 3 cm square on one side to prepare a colored polymer raw material.

[0076] raw material 14 An undyed plain cotton fabric was cut to prepare a colorless polymer raw material having a square shape with one side measuring approximately 3 cm.

[0077] raw material 15 A plain cotton fabric (dye weight ratio: 2.0% owf) that had been dyed yellow using a reactive dye (Dystar Remazol Golden Yellow RNL; CI Reactive Orange 107) was cut into pieces with a square shape measuring approximately 3 cm on one side, to prepare a colored polymer raw material.

[0078] raw material 16 An undyed plain rayon fiber fabric was cut to prepare a colorless polymer raw material having a square shape with one side measuring approximately 3 cm.

[0079] raw material 17 A plain rayon fiber fabric (dye weight ratio: 2.0% owf) that had been dyed yellow using a reactive dye (Dystar Remazol Golden Yellow RNL; CI Reactive Orange 107) was cut into pieces with a square shape measuring approximately 3 cm on one side, and prepared as a colored polymer raw material.

[0080] Comparison of reactivity depending on the type of polymer and extractant Example 1 About 0.1 g of the raw material 2 indigo (dye: Disperse Blue 56) polyester fiber was placed in a 50 ml vial containing 10.0 g of anisole (methoxybenzene) heated to 130°C in advance, and stirred for 10 minutes at 300 rpm using a magnetic stirrer. The polyester fiber was then removed using tweezers, immersed in 10.0 g of the same solvent (anisole) prepared in a 50 ml vial and maintained at 90°C for 1-2 seconds for cleaning, and then transferred to a glass evaporating dish. The fiber was then placed in a vacuum dryer maintained at 60°C under vacuum (≦2 mmHg) and dried for 12 hours or more to produce a fiber from which the dye had been removed.

[0081] The dye-removed fibers were measured using a spectrophotometer (manufacturer: Konica Minolta, model name: CM-3600A) to measure the color coordinates L * a * b * The value was measured. * a * b * The values ​​expressed as L are the coordinate values ​​of the color space standardized by the International Commission on Illumination (CIE). * is a number between 0 (black) and 100 (white) that represents the lightness. * and b * are values ​​expressed along the complementary color axes of red (+) / green (-) and yellow (+) / blue (-), respectively. The spectra of the fibers from which the dye was removed and the above raw materials 1 to 17 were measured using a near infrared spectrophotometer (NIR).

[0082] Example 2 Fibers were treated in the same manner as in Example 1, except that red (dye: Disperse Red 1) fiber of Raw Material 3 was used as the polyester fiber raw material.

[0083] Example 3 Fibers were treated in the same manner as in Example 1, except that raw material 4, red (dye: Disperse Red 9) fibers, were used as the polyester fiber raw material.

[0084] Example 4 The fibers were treated in the same manner as in Example 1, except that raw material 5, a black (dye: Dystar Dianix Deep Black Plus) fiber made by blending 82% polyester fiber and 18% spandex, was used as the raw material for the ester functional group-containing polymer fiber.

[0085] Example 5 Fibers were treated in the same manner as in Example 1, except that orange (dye: Acid Orange 116) nylon fiber of Raw Material 7 was used as the fiber raw material other than the ester functional group-containing polymer.

[0086] Example 6 Fibers were treated in the same manner as in Example 1, except that raw material 9, orange (dye: Acid Orange 116) wool fiber, was used as the fiber raw material other than the ester functional group-containing polymer.

[0087] Example 7 The fibers were treated in the same manner as in Example 1, except that orange (dye: Acid Orange 116) silk fibers (raw material 11) were used as the fiber raw material other than the ester functional group-containing polymer.

[0088] Example 8 The fibers were treated in the same manner as in Example 1, except that raw material 13, yellow (dye: Basic Yellow 28) acrylic fiber, was used as the fiber raw material other than the ester functional group-containing polymer.

[0089] Example 9 Fibers were treated in the same manner as in Example 1, except that raw material 15, yellow (dye: Reactive Orange 107) cotton fiber, was used as the fiber raw material other than the ester functional group-containing polymer.

[0090] Example 10 The fibers were treated in the same manner as in Example 1, except that raw material 17, yellow (dye: Reactive Orange 107) rayon fiber, was used as the fiber raw material other than the ester functional group-containing polymer.

[0091] Example 11 The fibers were treated in the same manner as in Example 1, except that ethyl benzoate was used as the extractant.

[0092] Example 12 The fibers were treated in the same manner as in Example 1, except that ethoxybenzene was used as the extractant.

[0093] Comparative Example 1 The fibers were treated in the same manner as in Example 1, except that triethyl phosphate was used as the extractant.

[0094] Comparative Example 2 The fibers were treated in the same manner as in Example 1, except that butyl butyrate was used as the extractant.

[0095] Comparative Example 3 The fibers were treated in the same manner as in Example 1, except that methoxycyclohexane was used as the extractant.

[0096] Comparative Example 4 The fibers were treated in the same manner as in Example 1, except that 1,4-xylene was used as the extractant.

[0097] Comparative Example 5 The fibers were treated in the same manner as in Example 1, except that morpholine was used as the extractant.

[0098] Comparative Example 6 The fibers were treated in the same manner as in Example 1, except that 1-methylpyrrolidin-2-one was used as the extractant.

[0099] Comparative Example 7 The fibers were treated in the same manner as in Example 1, except that methylsulfinylmethane was used as the extractant.

[0100] Comparative Example 8 Fibers were treated in the same manner as in Comparative Example 6, except that orange (dye: Acid Orange 116) nylon fiber of Raw Material 7 was used as the fiber raw material other than the ester functional group-containing polymer.

[0101] Comparative Example 9 Fibers were treated in the same manner as in Comparative Example 6, except that raw material 9, orange (dye: Acid Orange 116) wool fiber fabric, was used as the fiber raw material other than the ester functional group-containing polymer.

[0102] Comparative Example 10 The fibers were treated in the same manner as in Comparative Example 6, except that orange (dye: Acid Orange 116) silk fiber fabric (raw material 11) was used as the fiber raw material other than the ester functional group-containing polymer.

[0103] Comparative Example 11 Fibers were treated in the same manner as in Comparative Example 6, except that raw material 13, yellow (dye: Basic Yellow 28) acrylic fiber fabric, was used as the fiber raw material other than the ester functional group-containing polymer.

[0104] Comparative Example 12 Fibers were treated in the same manner as in Comparative Example 6, except that raw material 15 (yellow colored cotton fabric, dye: Reactive Orange 107) was used as the fiber raw material other than the ester functional group-containing polymer.

[0105] Comparative Example 13 The fibers were treated in the same manner as in Comparative Example 6, except that raw material 17, yellow (dye: Reactive Orange 107) rayon fabric, was used as the fiber raw material other than the ester functional group-containing polymer.

[0106] Comparative Example 14 Fibers were treated in the same manner as in Comparative Example 7, except that orange (dye: Acid Orange 116) nylon fiber of Raw Material 7 was used as the fiber raw material other than the ester functional group-containing polymer.

[0107] Comparative Example 15 Fibers were treated in the same manner as in Comparative Example 7, except that raw material 9, orange (dye: Acid Orange 116) wool fiber fabric, was used as the fiber raw material other than the ester functional group-containing polymer.

[0108] Comparative Example 16 The fibers were treated in the same manner as in Comparative Example 7, except that orange (dye: Acid Orange 116) silk fiber fabric (raw material 11) was used as the fiber raw material other than the ester functional group-containing polymer.

[0109] Comparative Example 17 Fibers were treated in the same manner as in Comparative Example 7, except that raw material 13, yellow (dye: Basic Yellow 28) acrylic fiber fabric, was used as the fiber raw material other than the ester functional group-containing polymer.

[0110] Comparative Example 18 The fibers were treated in the same manner as in Comparative Example 7, except that raw material 15, yellow (dye: Reactive Orange 107) cotton fiber fabric, was used as the fiber raw material other than the ester functional group-containing polymer.

[0111] Comparative Example 19 The fibers were treated in the same manner as in Comparative Example 7, except that raw material 17, yellow (dye: Reactive Orange 107) rayon fabric, was used as the fiber raw material other than the ester functional group-containing polymer.

[0112] Comparison of extractant effectiveness depending on fiber type FIG. 1 shows the degree to which dyes were removed by contacting ester functional group-containing colored polymer fibers and colored fibers other than ester functional group-containing polymer fibers with an extractant (anisole) according to Examples 1 to 10 of the present invention, and shows photographs of fibers that have undergone a decolorization process in which various types of fabrics are contacted with anisole heated to 130°C for 10 minutes under the conditions specified in Example 1 to extract dyes.

[0113] As shown in FIG. 1, after the decolorization process with anisole, the color-producing foreign matter in the ester functional group-containing polymer fiber was extracted, but the color-producing foreign matter in the fiber other than the ester functional group-containing polymer was not extracted.

[0114] Regarding the ester functional group-containing polymer fibers, the color of the fibers after bleaching was clearly brighter, regardless of the color of the starting raw material or the brightness, at a level that could be confirmed by visual inspection, and it was confirmed that there was almost no color change in fibers other than those made of ester functional group-containing polymers.

[0115] In Examples 1 to 10, the color space coordinates (L * a * b * ) are shown in Table 1. In Fig. 2, these are shown in two-dimensional coordinates (L * X * ) and plotted in plane coordinates.

[0116] [Table 1]

[0117] As shown in Table 1 above, the brightness values ​​measured by a spectrophotometer for the ester functional group-containing polymer fibers from which the dyes were removed in Examples 1 to 4 were very high, ranging from 78 to 86. The reason why the measured brightness did not reach 100 is due to the inherent characteristics of the measurement environment, which is due to the weaving characteristics of the fibers and the use of a dark surface as the background for fiber measurement. The a, which shows the complementary color axes of red / green and yellow / blue in the color coordinate system, * and b * The values ​​had very different values ​​for the original fibre colours, but for the bleached fibres they were below 17, showing a clear tendency towards neutral values.

[0118] On the other hand, as shown in Table 1 above, the brightness values ​​of the fibers (not polyester) after the bleaching process in Examples 5 to 10 measured by a spectrophotometer were 74.1 or less, which is almost the same as the brightness value of the initial raw material that has not been subjected to the bleaching process. * , b * The values ​​are also in the range of 26 to 89, which are relatively far from the neutral value, and it can be seen that the decolorization effect of the extractant acts only on the polyester functional group-containing polymer.

[0119] In the case of Example 4, the raw material was a polymer fiber made of a blend of polyester and spandex. The brightness value of the fiber before the bleaching process was about 16, which was very dark, but after the bleaching process, the brightness value was close to 78, and * and b *The values ​​of , and , respectively, were 1.2 and 5.0, and a clear dye removal effect was observed. These results clearly explain that the extractant proposed in the present invention can be used to remove color-producing foreign matter from ester functional group-containing polymer fibers in a blended form in which an ester functional group-containing polymer is mixed with other fibers, thereby improving the selection yield of the ester functional group-containing polymer. When expressing color in a blended fiber composed of a high concentration of ester functional group-containing polymer, disperse dyes are commonly used, which selectively dye only the ester functional group-containing polymer, so that the decolorization process according to the present invention can provide a method for effectively removing dyes and selecting a high concentration of ester functional group-containing polymer. In this case, the blended fiber containing a high concentration of ester functional groups may have a volume percentage of ester functional group-containing polymer of 30 volume % or more, preferably 50 volume %, and more preferably 80 volume % or more.

[0120] As shown in FIG. 2, the color space coordinates (L * a * b * ) into two-dimensional coordinate values, i.e., L * is the vertical axis, and a * and b * X expressed as the square root of the sum of the squares of each value * On the horizontal axis, L * is 60 or more, X * was observed to simultaneously satisfy values ​​of 50 or less.

[0121] From this, the color space coordinates of the fiber from which the dye has been removed (L * a * b * ) to two-dimensional coordinates (L * X * ) and discriminating the results, a relatively simple selection criterion can be presented, and it has been confirmed that this makes it possible to easily select polymer fibers containing ester functional groups.

[0122] FIG. 3 shows the difference in near-infrared spectrum of ester functional group-containing polymer fibers according to Examples 1 to 4 of the present invention. The color space coordinates (L * a * b * ) to two-dimensional coordinates (L * X * ), L * is 60 or more, X * is the result of measuring the spectrum using a near-infrared spectrophotometer after selecting fibers that simultaneously satisfy the range of 50 or less. When comparing the spectrum of fibers having coordinate values ​​that satisfy the above criteria, it can be seen that peaks with the same characteristics (corresponding to the characteristic peaks of polyester) are observed.

[0123] Comparison of decolorization effects depending on the type of extractant In Examples 1, 11, and 12 and Comparative Examples 1 to 5, the same conditions were applied except for the extractant used for decolorization in order to distinguish the decolorization effect due to different extractants, and raw material 2, indigo blue polyester fiber, was used as the fiber raw material. The temperature during the decolorization process was kept constant at 130°C.

[0124] FIG. 4 shows photographs of the fibers after the bleaching process in Examples 11 and 12 and Comparative Examples 1 to 5. Table 2 below shows the color space coordinates (L * a * b * ) and FIG. 5 shows the color space coordinates (L * a * b * ) is converted into two-dimensional plane coordinates.

[0125] [Table 2]

[0126] In the case of Example 1, the lightness (L *) is 85.5, and a indicates the complementary axis of the color * and b * The values ​​of 0.7 and 0.7 are close to the color coordinate values ​​of the colorless polyester fiber of Raw Material 1. It can be confirmed that ethyl benzoate and ethoxybenzene used in Examples 11 and 12 also act effectively in removing color-producing foreign matter, and the color coordinate values ​​of the fiber after bleaching are within the range indicating the standard for the dye removal effect proposed in the present invention.

[0127] In Comparative Examples 1 to 4, partial decolorization of the fibers was observed, but the amount of remaining dye was so large that it was easily visible to the naked eye, and the color coordinate values ​​of the fibers after the extraction agent treatment were also low in lightness (L * )55 or less, a * and b * Large negative deviations (green and blue) from the neutral value were observed.

[0128] When the extractant according to the present invention is brought into contact with a colored polymer fiber containing an ester functional group to remove the dye, the lightness (L * ) values ​​are all over 60, and the a * and b * The value of was measured to be almost close to the neutral value. The two-dimensional coordinate, i.e., the two-dimensional coordinate (L * X * ), the bleaching effect is L * is 60 or more, X * was observed in the range of 50 or less.

[0129] Methoxycyclohexane has a similar structure to anisole, which is one of the extractants according to the present invention, but the central functional group of the compound is changed to a saturated cycloalkane instead of an aromatic ring. When this was used as an extractant under the same conditions as in Example 1 (Comparative Example 3), as shown in Figure 5, it showed a much weaker dye removal effect than when anisole was used as an extractant (Example 1).

[0130] The color space coordinates (L * a * b * ) to two-dimensional coordinates (L * X * ), when the extractant having the chemical structure claimed in the present invention is used (Examples 11 and 12), the standard range (L * is 60 or more, X * In the case of Comparative Examples 1 to 4 in which a compound not having an aromatic ring structure as a central functional group was used as an extractant, the color coordinate values ​​of the fiber after bleaching were outside the standard range, indicating that the effect of the extractant was slight.

[0131] As mentioned above in the previous examples comparing the effects of extractants, when a substance having a chemical structure other than the extractant form (Chemical Formula 1 or Chemical Formula 2) claimed in the present invention was used as an extractant, the decolorization effect was observed to be low. This may be because the aromatic ring and the functional group bonded thereto interact with the ester functional group-containing polymer through pi bonds or hydrogen bonds.

[0132] Anisole (Example 1) and methoxycyclohexane (Comparative Example 3), which have the same carbon number and are classified into those in which a methoxy group is bonded to a hydrocarbon ring, or those in which the ring is configured as an unsaturated hydrocarbon structure (aromatic compounds) or a saturated hydrocarbon structure (cyclohexane), were added at different concentrations to the ester functional group-containing polymer, and the chemical shift change was observed using nuclear magnetic resonance (NMR) spectroscopy.

[0133] 13 Comparing the spectral results measured by C NMR (Figures 6 and 7), no chemical shifts were found in either case, implying that there was no significant change in the skeleton itself that constitutes the hydrocarbon compound.

[0134] For the ester-functionalized polymer in the sample containing each additive, 1Comparing the spectrum results measured by H NMR (FIGS. 8 and 9), when methoxycyclohexane was added as an extractant (Comparative Example 3), no chemical shift was observed, but when anisole was added as an additive (Example 1), a large downfield chemical shift occurred along with a change in the electron density of the hydrogen atoms constituting the terephthalate functional group and the methylene functional group.

[0135] This can be inferred from the fact that the extractant having the chemical formula structure claimed in the present invention exhibits high interaction with the ester functional group-containing polymer and heterogeneous molecules, and the addition of high concentrations of the extractant neutralizes the weak physical bond maintained between the dye and the polymer, from which point the de-dyeing of the fiber proceeds as the dye is irreversibly released from the polymer matrix.

[0136] The morpholine of Comparative Example 5 is L, which is the standard for selecting high purity polyester as claimed in the present invention. * is 60 or more, X * The dye removal effect was shown to be at a level that satisfied the condition of 50 or less. However, it was observed that morpholine reacted directly with the color-developing dye, causing a color change, and some of these components remained in the polymer matrix. Figure 10 shows the appearance of each solvent and the fiber after the dedying process of polyester fiber using anisole (methoxybenzene) used in Example 1 and morpholine in Comparative Example 5.

[0137] In both Example 1 and Comparative Example 5, raw material 2, indigo polyester fiber was used, but when morpholine was used, the indigo dye changed to a light orange color, and it was found that the changed dye component remained in the fiber after such a color change, taking on a faint orange color. In Comparative Example 5, the colored polyester fiber was decolorized, but this was due to a chemical change in the dye chromophore, which is different from the effect of the present invention in which decolorization proceeds due to the physical separation of the dye component from the polymer substrate.

[0138] Comparison of dedyeing effects using extractants and polymers Comparative Examples 6 to 19 are applied to the same extraction conditions as in Experimental Example 1 using compounds not having the chemical formula structure of the present invention, and are intended to explain the decolorizing effect on ester functional group-containing polymer fibers and fiber materials other than ester functional group-containing polymers. Table 3 below shows the types of polymers and extractants used in Comparative Examples 6 to 19, as well as the decolorizing effect of the extraction process in two-dimensional coordinates (L * , X * ) as shown.

[0139] [Table 3]

[0140] Figure 11 shows the morphology of fibers after extraction with extractants (1-methylpyrrolidin-2-one, methylsulfinylmethane) that do not have the chemical structure of the present invention but have a decolorizing effect on polymers containing ester functional groups. When 1-methylpyrrolidin-2-one and methylsulfinylmethane were used as extractants for various types of polymers, decolorization progressed in Comparative Examples 6 and 7, where polyester was used, and changes in the fibers were observed in the remaining cases, except for Comparative Examples 12, 13, and 18, where the extractants were used on fibers other than polyester. In particular, acrylic fibers were completely decomposed and could not be recovered.

[0141] The extractants used in Comparative Examples 6 to 19, which are not extractants having the structure of Formula 1 or Formula 2 according to the present invention, can exhibit a dedying effect on polymers containing ester functional groups, but may react with other types of polymers or dissolve to such an extent that they are difficult to apply to a sequential recycling process of polymers containing a mixture of multiple materials, and may also be difficult to apply to a sorting process for selectively separating and purifying polymers containing ester functional groups.

[0142] These results clearly explain that some of the compounds not having the structure of Formula 1 or Formula 2 claimed in the present invention are effective in dedying polymers containing ester functional groups, but are not suitable for use as extractants in the selection process according to the present invention.

[0143] De-dyeing experiments under mixed conditions of different types of polymers When the technology of the present invention is applied to an actual process, taking into consideration the fact that various types of polymers are mixed and treated with an extractant, the following experiment was carried out after mixing all the same raw materials as those used in Examples 1 to 10.

[0144] Example 13 The ester functional group-containing polymer fibers of raw materials 2 to 5 and the colored fibers other than the ester functional group-containing polymers of raw materials 7, 9, 11, 13, 15, and 17 (each 0.3 g) were mixed, and the fiber mixture was subjected to a de-dyeing treatment using a Soxhlet extraction method.

[0145] Anisole (methoxybenzene) (150 g) was used as the extractant, and the fibers after contact with the extractant were washed with ethanol, transferred to a glass evaporating dish, and placed in a vacuum dryer maintained at 80°C under vacuum (≦2 mmHg), and then dried for more than 12 hours.

[0146] The dye-removed fiber was measured using a spectrophotometer in the same manner as in Example 1 to determine the color space coordinates (L * a * b * ) and calculate the two-dimensional coordinate (L * X * ), L * Value is 60 or more, X * After classifying the fibers into those that satisfied the value of 50 or less and those that did not, the optical spectra of these were measured using a near-infrared spectrophotometer.

[0147] Fig. 12 is a diagram showing the color change of the colored fiber mixture before and after extraction with an extractant using a Soxhlet extractor. As shown in Fig. 12, when the fibers mixed in the Soxhlet extractor are contacted with the extractant, selective decolorization proceeds only in specific fibers (polyester fibers of raw materials 2 to 5).

[0148] The results of measuring the fiber after the extraction process shown in FIG. 12 using a spectrophotometer were plotted on two-dimensional coordinates (L* X * ), L * Value is 60 or more, X * Fibers that satisfied the value of 50 or less were selected and their spectra were measured using a near-infrared spectrophotometer. The results are shown in FIG.

[0149] As shown in Figure 13, the spectroscopic spectra of fibers having coordinate values ​​within the above specified range (which coincide with the spectrum in Figure 3) confirmed that all of them were polymers containing ester functional groups.

[0150] FIG. 14 shows the spectrum measured by a near-infrared spectrophotometer for fibers (nylon, wool, silk, acrylic, cotton, rayon) other than ester functional group-containing polymer fibers. When fibers that have not been decolorized are randomly selected and measured by a near-infrared spectrophotometer, one of the spectra shown in FIG. 14 is observed, not the spectrum shown in FIG. 3 or FIG. 13. This fully explains that the above-mentioned decolorization process of colored mixed fibers can very selectively and efficiently remove only the disperse dyes dyed on the ester functional group-containing fibers. As can be seen from FIG. 12, it explains that the dyes previously introduced into each waste fiber can be used as indicators for chemically sorting the ester functional group-containing polymers after the decolorization process. Therefore, this technology has the advantage that it is not necessary to add a separate new material for sorting after the decolorization process.

[0151] As can be seen from Figures 12 to 14, when decolorization treatment is performed using the extractant proposed in the present invention, it is possible to selectively decolorize only ester functional group-containing polymer fibers even under conditions in which fibers are mixed, and it has been confirmed that it is possible to classify and select ester functional group-containing polymer materials based only on clearly separable color discrimination criteria.

[0152] Method for preventing the selective rejection of colorless polymers by adding a dyeing process to the raw material Since the polymers discharged from waste materials include not only colored polymers but also white or transparent polymers, the following experiment was carried out to explore the possibility of sorting ester functional group-containing polymers from a polymer mixture in which colored and colorless polymers are mixed together.

[0153] Example 14 0.01 g of red disperse dye (Disperse Red 9) is added to a 30 ml vial containing 5.0 g of anisole and heated to 120°C. Approximately 0.1 g of the colorless polyester fiber of raw material 1 is added to a 30 ml vial containing anisole and red disperse dye (Disperse Red 9), and after being kept for 2 minutes, it is washed with ethanol. The washed fiber after dyeing is transferred to a glass evaporating dish and placed in a vacuum dryer maintained at 60°C under vacuum (≦2 mmHg), and then dried for 12 hours or more. The color space coordinates (L * a * b * ) to two-dimensional coordinates (L * , X * ) are shown in Table 4.

[0154] Comparative Example 20 Dyeing was carried out in the same manner as in Example 14, except that undyed nylon fiber of raw material 6 was used as the fiber raw material other than the ester functional group-containing polymer, and the color space coordinates (L * a * b * ) to two-dimensional coordinates (L * , X * ) are shown in Table 4.

[0155] Comparative Example 21 Dyeing was carried out in the same manner as in Example 14, except that undyed wool fiber of raw material 8 was used as the fiber raw material other than the ester functional group-containing polymer, and the color space coordinates (L * a * b * ) to two-dimensional coordinates (L * , X * ) are shown in Table 4.

[0156] Comparative Example 22 Dyeing was carried out in the same manner as in Example 14, except that undyed silk fiber of raw material 10 was used as the fiber raw material other than the ester functional group-containing polymer, and the color space coordinates (L * a * b * ) to two-dimensional coordinates (L * , X * ) are shown in Table 4.

[0157] Comparative Example 23 The fibers were dyed in the same manner as in Example 14, except that undyed acrylic fibers of raw material 12 were used as the fiber raw material other than the ester functional group-containing polymer, and the color space coordinates (L * a b * ) to two-dimensional coordinates (L * , X * ) are shown in Table 4.

[0158] Comparative Example 24 The fibers were dyed in the same manner as in Example 14, except that undyed cotton fibers of raw material 14 were used as the fiber raw material other than the ester functional group-containing polymer, and the color space coordinates (L * a * b * ) to two-dimensional coordinates (L * , X * ) are shown in Table 4.

[0159] Comparative Example 25 The fibers were dyed in the same manner as in Example 14, except that undyed rayon fiber of raw material 16 was used as the fiber raw material other than the ester functional group-containing polymer, and the color space coordinates (L * a * b * ) to two-dimensional coordinates (L * , X * ) are shown in Table 4.

[0160] [Table 4]

[0161] The mixed solution of red disperse dye and anisole used in Example 14 and Comparative Examples 20 to 25 simulates the waste extract containing disperse dye extracted from colored polyester fibers using an extractant. The extraction residue generated in the selective decolorization process previously described as Examples 1 to 10 only contains the disperse dye selectively extracted from polyester fibers, and is therefore different in color from the simulated solution. That is, the simulated mixed solution and the waste extract can have the same dyeing effect and dyeing principle in the re-dyeing process.

[0162] As shown in Figure 15, when visually inspected immediately after extracting the fibers from the vial, all of the fibers appeared to be dyed, but after washing with ethanol, most of the dye on the fibers other than polyester was removed.

[0163] FIG. 16 shows the color space coordinate values ​​shown in Table 4 as coordinates (L * X * 16. As shown in Fig. 16, when the dye-containing extractant is brought into contact with the fibers in the methods of Example 14 and Comparative Examples 20 to 25, it can be seen that the ester functional group-containing polymer fibers are selectively dyed, and it can be confirmed that the dyeing effect is insignificant for the other fibers.

[0164] Re-dyeing and bleaching using waste extractant generated after bleaching As described above, Example 15 and Comparative Examples 26 to 31 confirmed the possibility of using the waste extractant generated after the decolorization process included in the present invention to selectively dye ester functional group-containing polymers from white or transparent polymer mixtures contained in waste.

[0165] Example 15 The dyeing process was carried out under the same conditions as in Example 14 and Comparative Examples 20 to 25, except that anisole (hereinafter, waste extractant) containing residual disperse dyes generated after the decolorization process of the polymer mixture of Example 13 was used. The color space coordinates (L * a * b * ) to two-dimensional coordinates (L * , X * ) are shown in Table 5. Undyed polyester fiber of raw material 1 was used as the fiber raw material, and the fiber that was dyed and dried was subjected to a decolorization process under the same conditions as in Examples 1 to 10.

[0166] Comparative Example 26 The dyeing and decolorizing processes were carried out in the same manner as in Example 15, except that undyed nylon fiber of raw material 6 was used as the fiber raw material other than the ester functional group-containing polymer. The color change of the fiber after the dyeing process was measured using a spectrophotometer and expressed as color space coordinates (L * a * b * ) to two-dimensional coordinates (L * , X * ) are shown in Table 5.

[0167] Comparative Example 27 The dyeing and bleaching processes were carried out in the same manner as in Example 15, except that undyed wool fiber of raw material 8 was used as the fiber raw material other than the ester functional group-containing polymer. The color change of the fiber after the dyeing process was measured using a spectrophotometer in terms of color space coordinates (L * a * b * ) to two-dimensional coordinates (L * , X * ) are shown in Table 5.

[0168] Comparative Example 28 The dyeing and bleaching processes were carried out in the same manner as in Example 15, except that undyed silk fiber of raw material 10 was used as the fiber raw material other than the ester functional group-containing polymer. The color change of the fiber after the dyeing process was measured using a spectrophotometer in terms of color space coordinates (L * a * b *) to two-dimensional coordinates (L * , X * ) are shown in Table 5.

[0169] Comparative Example 29 The dyeing and decolorizing processes were carried out in the same manner as in Example 15, except that undyed acrylic fiber of raw material 12 was used as the fiber raw material other than the ester functional group-containing polymer. The color change of the fiber after the dyeing process was measured using a spectrophotometer and expressed as color space coordinates (L * a * b * ) to two-dimensional coordinates (L * , X * ) are shown in Table 5.

[0170] Comparative Example 30 The dyeing and bleaching processes were carried out in the same manner as in Example 15, except that undyed cotton fiber of raw material 14 was used as the fiber raw material other than the ester functional group-containing polymer. The color change of the fiber after the dyeing process was measured using a spectrophotometer to determine the color space coordinates (L * a * b * ) to two-dimensional coordinates (L * , X * ) are shown in Table 5.

[0171] Comparative Example 31 The dyeing and decoloring processes were carried out in the same manner as in Example 15, except that undyed rayon fiber of raw material 16 was used as the fiber raw material other than the ester functional group-containing polymer. The color change of the fiber after the dyeing process was measured using a spectrophotometer and expressed as color space coordinates (L * a * b * ) to two-dimensional coordinates (L * , X * ) are shown in Table 5.

[0172] [Table 5]

[0173] The waste extractant used in the dyeing process in Example 15 and Comparative Examples 26 to 31 is an extractant residual liquid generated in the selective decolorization process of the ester functional group-containing polymer from the polymer mixture previously described in Example 13, and contains only the disperse dye selectively extracted from the polyester fiber, so it only differs in color from the simulated solution. That is, the simulated mixed solution and the waste extractant can have the same dyeing effect and dyeing principle in the re-dyeing process.

[0174] FIG. 17 shows the color space coordinate values ​​shown in Table 5 as two-dimensional coordinates (L * X * 17. As shown in Fig. 17, when the waste extractant generated in the decolorization process is brought into contact with fibers according to the methods of Example 15 and Comparative Examples 26 to 31, it can be seen that the ester functional group-containing polymer fibers are selectively dyed, and it can be confirmed that the dyeing effect is insignificant for other fibers.

[0175] Figure 18 shows the color change of polyester fiber re-dyed and bleached by Example 15. As shown in Figure 16, when fibers are re-dyed and bleached by the methods of Example 15 and Comparative Examples 26 to 31, it is possible to recycle waste extractant to dye colorless ester functional group-containing polymer fiber, and the dye introduced from the waste extract can be effectively removed by the bleaching technique included in the present invention.

[0176] From this, it can be seen that by selectively dyeing colorless polymers containing ester functional groups contained in a waste polymer mixture and then removing the dye, it is possible to select polymers containing ester functional groups from a polymer mixture containing various types of polymers, regardless of whether they are colored or colorless, by the method of the present invention.

[0177] In addition, the residual extractant solution recovered from the chemical separation process of the present invention contains a high concentration of disperse dyes that can be dyed, so it can be reused in the dyeing process, making it possible to realize a very economical and environmentally friendly waste fiber recycling process.

[0178] As described above, the specific parts of the present invention have been described in detail. It is obvious to those skilled in the art that such specific techniques are merely preferred embodiments and do not limit the scope of the present invention. Therefore, the substantial scope of the present invention should be defined by the appended claims and their equivalents.

Claims

1. An extractant for selectively eluting and removing foreign matter that exhibits color only in the ester functional group-containing polymer from a colored polymer mixture in which an ester functional group-containing colored polymer and a different type of colored polymer are mixed, the extractant comprising: The extractant is an extractant for selectively eluting and removing impurities that selectively exhibit color only in an ester functional group-containing polymer from the polymer mixture, the extractant comprising at least one of a compound represented by the following Chemical Formula 1 and a compound represented by the following Chemical Formula 2: 【Chemistry 1】 (In the above Chemical Formula 1, A １ is selected from a carboxyl group, an aldehyde group, and a nitrile group; R １ is any one selected from a hydroxyl group, a carboxyl group, an aldehyde group, a nitrile group, a linear or branched saturated hydrocarbon having 1 to 6 carbon atoms, a linear or branched unsaturated hydrocarbon having 1 to 6 carbon atoms, a cycloalkyl group having 4 to 6 carbon atoms, and an aryl group having 6 to 12 carbon atoms, and m is any integer selected from 0 to 5, and when m is 2 or more, R １ may be the same or different, n is an integer selected from 1 to 6, and when n is 2 or more, A １ may be the same or different, In the above Chemical Formula 2, A ２ is at least one of an ester, an ether, and a carbonyl; R ２ is an alkyl group having 1 to 10 carbon atoms, n is an integer selected from 1 to 6, and when n is 2 or more, A ２ and R ２ may be the same or different, R １ The definitions of and m are the same as those of Chemical Formula 1.

2. The compound represented by Chemical Formula 1 or Chemical Formula 2 includes 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, 1,2,4-triethoxybenzene, 1,3,5-triethoxybenzene, 1,2,3,4-tetramethoxybenzene, 1,2, 3,5-tetramethoxybenzene, 1,2,4,5-tetramethoxybenzene, 1-methoxy-2-methylbenzene, 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-methyl 1-methoxy-2-prop-2-enylbenzene, 1-methoxy-3-prop-1-enylbenzene, 1-methoxy-3-prop-2-enylbenzene, 1-methoxy-4-prop-2-enylbenzene, 1-methoxy-4-[(E)-prop-1-enyl]benzene (cis), 1-methoxy-4-[(E)-prop-1-enyl]benzene (trans), methyl benzoate, ethyl benzoate, butyl benzoate, propyl benzoate, methyl 2-ethoxybenzoate, methyl 3-ethoxybenzoate, methyl 4-ethoxybenzoate ester, ethyl 2-ethoxybenzoate, ethyl 3-ethoxybenzoate, ethyl 4-ethoxybenzoate, ethyl (E) 3-(4-hydroxy-3,5-dimethoxyphenyl)prop-2-enoate, 2,3-dimethoxy-4-methylbenzoic acid, 2,3-dimethoxybenzoic acid, 2,4-dimethoxybenzoic acid, 2,4-dihydroxybenzoic acid, 2,5-dimethoxy-4-methylbenzoic acid, 2,5-dimethoxybenzoic acid, 2,5-dihydroxybenzoic acid, 2,6-dimethoxy-4-methylbenzoic acid, 2,6-dimethoxybenzoic acid, 2,6-Dihydroxybenzoic acid, 2-methoxybenzoic acid, 2-ethoxy-3-ethylbenzoic acid, 2-ethoxybenzoic acid, 2-hydroxy-3-methoxybenzoic acid, 2-hydroxy-4,5-dimethoxybenzoic acid, 2-hydroxy-4,6-dimethoxybenzoic acid, 2-hydroxy-4-methoxybenzoic acid, 2-hydroxy-5-methoxybenzoic acid, 2-hydroxy-6-methoxybenzoic acid, 2-hydroxybenzoic acid, 3-(4-hydroxy-3,5-dimethoxyphenyl)prop-2-ene Acid, 3,4-dimethoxybenzoic acid, 3,4-dihydroxybenzoic acid, 3,5-dimethoxy-4-methylbenzoic acid, 3,5-dimethoxybenzoic acid, 3-methoxybenzoic acid, 3-ethoxy-4-hydroxybenzoic acid, 3-ethoxy-5-ethylbenzoic acid, 3-ethoxybenzoic acid, 3-hydroxy-4,5-dimethoxybenzoic acid, 3-hydroxy-4-methoxybenzoic acid, 3-hydroxy-5-methoxybenzoic acid, 3-hydroxybenzoic acid, 4-methoxybenzoic acid, 4-ethoxy-2-ethyl Benzoic acid, 4-ethoxy-3-ethylbenzoic acid, 4-ethoxybenzoic acid, 4-hydroxy-2,6-dimethoxybenzoic acid, 4-hydroxy-2,6-dimethylbenzoic acid, 4-hydroxy-2-methoxybenzoic acid, 4-hydroxy-3,5-dimethoxybenzoic acid, 4-hydroxy-3,5-dimethylbenzoic acid, 4-hydroxy-3-methoxybenzoic acid, 4-hydroxybenzoic acid, ethyl 2-methoxybenzoic acid, ethyl 3-methoxybenzoic acid, ethyl 4-methoxybenzoic acid, 2,3-dimethyl 2-methoxyphenol, 2,4-dimethoxyphenol, 2,5-dimethoxyphenol, 2,6-dimethoxy-4-prop-2-enylphenol, 2,6-dimethoxyphenol, 2-[(E)-prop-1-enyl]phenol, 2-methoxy-4-(prop-1-enyl)phenol, 2-methoxy-4-prop-2-enylphenol, 2-methoxyphenol, 2-ethoxyphenol, 2-tert-butyl-4-methoxyphenol, 3,4-dimethoxyphenol, 3,5-dimethoxyphenol, 3-methoxyphenol, 3-ethoxyphenol, 3-tert-butyl-4-methoxyphenol, 3-prop-1-en-2-ylphenol, 4-(prop-1-en-2-yl)phenol, 4-(prop-2-en-1-yl)phenol, 4-methoxy-2-[(E)-prop-1-enyl]phenol, 4-methoxyphenol, 4-ethoxyphenol, 4-ethyl-2,3-dimethylphenol, 4-ethyl-2,5-dimethoxyphenol, 4-ethyl-2,6-dimethoxyphenol, 4-tert-butyl-4-methoxyphenol, t-Butyl-2-methoxyphenol, 1-(2-hydroxy-4,6-dimethylphenyl)ethanone, 1-(4-methoxyphenyl)ethanone, 1-(4-hydroxy-2,6-dimethoxyphenyl)ethanone, 1-(4-hydroxy-3,5-dimethoxyphenyl)ethanone, 1-(5-hydroxy-2,4-dimethylphenyl)ethanone, 1-phenylbutan-1-one, 1-phenylethanone, 1-phenylpropan-1-one, 2,3-dihydroxybenzaldehyde, 2,4-dihydroxybenzaldehyde, 2,5-dihydroxybenzaldehyde aldehyde, 2-methoxybenzaldehyde, 2-methylbenzaldehyde, 2-butoxybenzaldehyde, 2-ethoxybenzaldehyde, 2-hydroxy-3,5-dimethoxybenzaldehyde, 2-hydroxy-3-methoxybenzaldehyde, 2-hydroxy-4,6-dimethoxybenzaldehyde, 2-hydroxy-4-methoxybenzaldehyde, 2-hydroxy-5-methoxybenzaldehyde, 2-hydroxy-6-methoxybenzaldehyde, 2-hydroxybenzaldehyde, 3,4-dihydroxybenzaldehyde, 3,5-dihy hydroxybenzaldehyde, 3-methoxybenzaldehyde, 3-methylbenzaldehyde, 3-butoxybenzaldehyde, 3-ethoxy-2-hydroxybenzaldehyde, 3-ethoxybenzaldehyde, 3-hydroxy-2-methoxybenzaldehyde, 3-hydroxy-4-methoxybenzaldehyde, 3-hydroxy-5-methoxybenzaldehyde, 3-hydroxybenzaldehyde, 4-methoxybenzaldehyde, 4-methylbenzaldehyde, 4-butoxybenzaldehyde, 4-ethoxybenzaldehyde, 4-hydroxy-2,The extractant for selectively eluting and removing foreign matter that exhibits color only in the ester functional group-containing polymer from the polymer mixture according to claim 1, characterized in that the extractant is at least one selected from the group consisting of 6-dimethoxybenzaldehyde, 4-hydroxy-2-methoxybenzaldehyde, 4-hydroxy-3,5-dimethoxybenzaldehyde, 4-hydroxy-3-methoxybenzaldehyde, 4-hydroxybenzaldehyde, benzaldehyde, 2,3-dihydroxybenzonitrile, 2,4-dihydroxybenzonitrile, 2,5-dihydroxybenzonitrile, 2,6-dihydroxybenzonitrile, 2-methoxybenzonitrile, 2-methylbenzonitrile, 2-hydroxybenzonitrile, 3,4-dihydroxybenzonitrile, 3-methoxybenzonitrile, 3-methylbenzonitrile, 3-hydroxybenzonitrile, 4-methoxybenzonitrile, 4-methylbenzonitrile, 4-acetylbenzonitrile, 4-hydroxybenzonitrile, and benzonitrile.

3. A method for selecting an ester functional group-containing polymer from a colored polymer mixture comprising an ester functional group-containing colored polymer and a different type of colored polymer, the method comprising the steps of: (a) contacting a polymer mixture containing an ester functional group-containing colored polymer and a different type of colored polymer with an extractant that extracts color-producing foreign matter, thereby selectively decolorizing the ester functional group-containing colored polymer; (b) separating the decolorized polymer from the non-decolorized polymer in the step (a) by utilizing the color difference; a method for separating an ester functional group-containing polymer from the polymer mixture, comprising:

4. 4. The method for separating an ester functional group-containing polymer from a polymer mixture according to claim 3, wherein the ester functional group-containing polymer is in the form of a fiber or a fabric, and the fabric is a blend of an ester functional group-containing polyester fiber alone or a blend of an ester functional group-containing polyester fiber and at least one of polyethylene, polypropylene, polystyrene, polyvinyl chloride, cotton, hemp, wool, rayon, acetate, acrylic, nylon, and spandex.

5. The colored polymer is a polymer that is colored by a foreign substance that exhibits one or more colors, and the polymer mixture has color space coordinates (L ＊ a ＊ b ＊ ) into two-dimensional coordinates (L ＊ X ＊ (X ＊ is a ＊ and b ＊ When the coordinate value L is converted to the square root of the sum of the squares of the values, ＊ is 60 or more, X ＊ The method for selecting an ester functional group-containing polymer from the polymer mixture according to claim 3, wherein polymers satisfying a value of 50 or less are excluded.

6. 4. The method for separating an ester functional group-containing polymer from a polymer mixture according to claim 3, wherein the decolorization process in step (a) is carried out at a temperature in the range of 70 to 200°C.

7. The color space coordinates (L ＊ a ＊ b ＊ ) into two-dimensional coordinates (L ＊ X ＊ (X ＊ is a ＊ and b ＊ When the coordinate value L is converted to the square root of the sum of the squares of the values, ＊ is 60 or more, X ＊ The method for separating an ester functional group-containing polymer from a polymer mixture according to claim 3, wherein the ratio of the ester functional group-containing polymer to the ester functional group-containing polymer is 50 or less.

8. A method for selecting an ester functional group-containing polymer from a polymer mixture containing an ester functional group-containing polymer and a different type of polymer, comprising the steps of: (i) a step of contacting a color-producing foreign substance with a polymer mixture in which an ester functional group-containing polymer and a different type of polymer are mixed, thereby selectively dyeing only the ester functional group-containing polymer; (ii) removing colorless polymers from the mixture of polymers using color differences in the mixture after step (i); (iii) contacting the mixture obtained after step (ii) with an extractant capable of extracting color-producing foreign substances to selectively decolorize only the colored polymer containing ester functional groups; (iv) separating the decolorized polymer from the non-decolorized polymer by utilizing color difference.

9. In the step (ii), the color space coordinates (L ＊ a ＊ b ＊ ) into two-dimensional coordinates (L ＊ X ＊ (X ＊ is each a ＊ b ＊ When converted to the square root of the sum of the squares of the coordinate values, ＊ is 60 or more, X ＊ The method for selecting an ester functional group-containing polymer from the polymer mixture according to claim 8, further comprising excluding polymers that satisfy a value of 50 or less.

10. The color space coordinates (L ＊ a ＊ b ＊ ) into two-dimensional coordinates (L ＊ X ＊ (X ＊ is a ＊ b ＊ When the coordinate value L is converted to the square root of the sum of the squares of the values, ＊ is 60 or more, X ＊ The method for separating an ester functional group-containing polymer from a polymer mixture according to claim 8, wherein the ratio of the ester functional group-containing polymer to the ester functional group-containing polymer is 50 or less.

11. 9. The method for separating an ester functional group-containing polymer from a polymer mixture according to claim 8, wherein the dyeing in step (i) is carried out by recovering a waste extractant solution containing the color-producing foreign matter obtained in step (iii) and mixed therein.

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