KR102522806B1 - Agent for decolorization of colored polymer resins containing ester functional groups and method for decolorization the same - Google Patents

Abstract

The present invention relates to an extractant and a method for removing color-expressing foreign substances from a colored polymer containing an ester functional group, and more particularly, as represented by Formula 1 below, at least one alkyl group on an aromatic ring. is connected through a linker, and the linker relates to an extractant containing a hydrophobic organic compound having at least one oxygen and a method for removing a foreign substance expressing color from a colored polymer containing an ester functional group using the extractant. will be.
[Formula 1]

Description

Extraction agent for removing color-expressing foreign substances from colored polymers containing ester functional groups and method for removing the same

The present invention relates to an extractant for removing color-expressing foreign substances from a colored polymer containing an ester functional group and a method thereof, and more particularly, to effectively separate dyes from colored polyester fibers containing dyes. And an extractant for desorption and a method for eluting most of the dye from the polyester fiber by adding the extractant to the polyester fiber while maintaining the temperature in a specific range.

As the industry develops, the increased use of fibers and plastics is causing various environmental and social problems. Recently, in order to solve these problems, physical or chemical recycling technology that applies waste fibers or waste plastic materials discharged after use as raw materials has attracted high attention. Polymer materials containing ester functional groups among waste plastics and waste fibers have thermoplastic properties and can be converted into low-molecular materials through chemical reactions, and can be used in the recycling industry to manufacture recycled materials through physical and chemical recycling processes. , In general, most of the polymer materials discharged after consumption are contaminated with various foreign substances, and contamination of such foreign substances is pointed out as one of the biggest problems in the technology for recycling and increasing the polymer material.

Polymer resins containing ester functional groups as described above are very widely used in the form of materials into which color-expressing foreign substances are introduced, and dyes or pigments can be cited as representative examples. Unlike pigments that are dispersed and used in a solvent in the form of powder particles, dyes can be uniformly soluble in most solvents and can have a very small particle size or be in the form of molecules. Pigments are mostly applied to polymer resins by paint or printing methods, but dyes are used through a coloring process and are mostly used to dye textiles or leather. Dyes are again classified into natural dyes obtained from plants, animals, or minerals, and artificial dyes synthesized artificially. Examples of artificial dyes include direct dyes, mordant dyes, reducing dyes, chromogenic dyes, dispersible dyes, and reactive dyes. Dyes mainly applied to polymer materials containing ester functional groups can be classified by chemical structure. Azo-based and anthraquinone-based disperse dyes are most commonly used.

Foreign substances that express color in the polymer resin containing the ester functional group as described above are many of those manufactured so as not to be easily separated from everyday living environments or conditions of use in order to prevent discoloration during use or washing. In particular, dyes It is mainly used to express the color of polyester fiber through the coloring process, and since the dye molecule in the colored fiber exists in the form of a complex with the polymer substrate, it is easy to separate or remove the dye by simple contact with water or organic solvent. not.

As such, waste polyester resin containing a large amount of impurities that are difficult to separate is difficult to secure economic feasibility due to restrictions on the use and quality of recycled materials produced during physical and chemical recycling or the burden of the purification process for high added value of the product. . Therefore, colored waste polyester is one of polymers with very low utilization in the field of recycling or recycling, and is known as a waste resource that causes environmental problems because most of it is discarded or incinerated.

Therefore, it is necessary to develop a very effective and economical separation technology in removing color-expressing foreign substances from colored polymer resins containing ester functional groups. To this end, it is necessary to design a low-cost material that can effectively remove color-expressing foreign substances only by direct contact with a colored polymer resin containing an ester functional group, and to identify optimal conditions for a process using the same.

In addition, the polymer resin prepared through the above process may have some or trace impurities remaining, and in the process of adding high value through physical regeneration or chemical regeneration, the quality of the final product is improved through an easy and economical additional purification process before synthesizing the polymer material. In many cases, raw materials of the same or similar level are required.

Therefore, a material applied to remove foreign substances exhibiting color from a colored polymer resin containing an ester functional group must be inexpensive and low in hazard, and must not provide uneconomic factors for a regeneration process that can be performed sequentially.

On the other hand, conventional techniques for removing pigments from polymers containing ester functional groups include an adsorption method using a strong adsorbent such as activated carbon, a physical separation method such as filtration or distillation, and a chemical reaction such as oxidation, reduction, hydrolysis, or electrolysis. There are ways. These methods may be performed in parallel with a chemical depolymerization reaction or as a post-treatment process. U.S. Patent Publication Nos. 2015-0059103 A1 and 2009-0133200 A1 disclose techniques for removing dyes by directly applying an aromatic compound paraxylene as an extractant to a polymer containing an ester functional group, and Japanese Patent Publication No. 6659919 B2 discloses carbon A technique for removing dye by contacting polyester with an extractant containing 90% by mass or more of glycol monoether having 8 to 15 atoms is known, but due to the reversible dyeing property of the dye, the decolorization effect is often fragmentary. , The solvent itself used in the separation process is often harmful to the human body or expensive, and it is difficult to secure economic feasibility and produce eco-friendly products because the application temperature is very high.

In order to solve the above-mentioned problems, it is necessary to develop an extraction solvent that can effectively remove dyes from colored polymers containing ester functional groups, has relatively low harm to the human body and does not consume excessive energy, or a de-dyeing process using the same. The situation is.

US Patent Publication 2015-0059103 A1 (2015.03.05. Publication date) US Patent Publication 2009-0133200 A1 (2009.05.28. Publication date) Japanese Laid Open Patent Document 6659919 B2 (2020.03.04. Publication date)

The present invention was created to solve the above problems, by lowering the mutual attraction between a polymer containing an ester functional group and a dye dyed therein to induce separation from the matrix of the polymer, and a large amount of solvent to which the separated dye is added. An object of the present invention is to provide an extractant for removing color-expressing foreign substances from a polymer resin containing an ester functional group, which can suppress or minimize re-dyeing to the polymer resin by maintaining affinity.

In addition, the present invention is an extractant for removing foreign substances exhibiting color from a polymer resin containing an ester functional group, wherein at least one alkyl group is connected to an aromatic ring through a linker, and the linker is a hydrophobic hydrophobic having at least one oxygen. An object of the present invention is to provide an extractant for removing color-expressing foreign substances from a polymer resin containing an ester functional group, including a compound represented by an organic compound.

In addition, the present invention applies a method such as one-time simple extraction, repeated extraction, or continuous extraction by heating the extractant to a temperature of 100 to 200 ° C. and then directly contacting it with a polymer resin containing an ester functional group to change color. An object of the present invention is to provide a method for removing color-expressing foreign substances from a polymer resin containing an ester functional group, which separates foreign substances that express.

In addition, the present invention resupplies the vaporized extractant by heating the mixed extraction solution containing the dye to continuous reflux, and induces continuous contact with the polymer resin containing the ester functional group of the extractant in a certain volume, thereby effectively removing the dye. The purpose is to provide a method for removing foreign matter that expresses color from a polymer resin containing an ester functional group.

In addition, an object of the present invention is to provide a method for removing residual dye from a reaction product after applying chemical depolymerization to a polymer resin containing an ester functional group from which dye is removed and the extractant absorbed therein. there is. In addition, in the regeneration process of the polymer resin containing the ester functional group, the present invention has a characteristic that does not participate in a chemical depolymerization reaction and forms an unstable liquid-liquid phase with a hydrophilic solvent, which is a depolymerization reaction product, and includes an ester functional group. The purpose is to provide an extractant for removing foreign substances that express color from a polymer resin.

An extractant for removing color-expressing foreign substances from a colored polymer resin containing an ester functional group according to an embodiment of the present invention is characterized by comprising a compound represented by Formula 1 below.

[Formula 1]

(In Formula 1, R ₁ is any one selected from hydrogen, a hydroxy group, an aldehyde group, a carboxyl group, a C ₁ -C ₆ alkyl group, a C ₄ -C ₆ cycloalkyl group, and a C ₆ -C ₁₂ aryl group, n is any one integer from 0 to 5, and when n is 2 or more, R ₁ are the same or different, R ₂ is a C ₁ -C ₁₀ alkyl group, and m is any one of 1 to 6 It is an integer of, and when m is 2 or more, -OR ₂ are each the same or different.)

In addition, as an example of the extractant, the compound represented by Formula 1 is methoxy benzene, 1,2-dimethoxybenzene, 1,3-dimethoxybenzene, 1,4-dimethoxybenzene, 1,2 ,3-trimethoxybenzene, 1,2,4-trimethoxybenzene, 1,3,5-trimethoxybenzene, 1,2,3,4-tetramethoxybenzene, 1,2,3,5 -Tetramethoxybenzene, 1,2,4,5-tetramethoxybenzene, 2-methoxyphenol, 1,3-dimethoxy-2-hydroxybenzene, 4-hydroxy-3,5-dimethoxybenzo Iksan, 3-(4-hydroxy-3,5-dimethoxyphenyl)prop-2-enal, 4-hydroxy-3,5-dimethoxybenzaldehyde, 4-hydroxy-3,5-dime Toxyacetophenone, 3-(4-hydroxy-3,5-dimethoxyphenylprop-2-enoic acid, 4-ethyl-2,6-dimethoxyphenol, 4-hydroxy-3-methoxybenzaldehyde Hydroxy, 3-hydroxy-4-methoxybenzaldehyde, 2-hydroxy-3-methoxybenzaldehyde, 2-hydroxy-5-methoxybenzaldehyde, 2-hydroxy-4-methoxy Benzaldehyde, 3,4-dihydroxybenzaldehyde, 1-methoxy-4-[(E)-prop-1-enyl] benzene, 1-bromo-4-methoxybenzene, 2-tert -Butyl-4-methoxyphenol, ethoxybenzene, 1,3,5-trichloro-2-methoxybenzene, 1,3,5-tribromo-2-methoxybenzene, 4-(prop- 2-en-1-yl) phenol, 1-methoxy-4 (prop-2-en-1-yl) benzene, 5- (prop-2-en-1-yl) -2H-1,3 - from the group consisting of benzodioxole, 4-methoxy-2-[(E)-prop-1-enyl]phenol, 2-methoxy-4-(prop-2-en-1-yl)phenol It is characterized in that at least one selected.

In addition, as an embodiment of the extractant, the colored polymer resin containing the ester functional group is a polymer resin colored by a foreign substance expressing one or more colors, and the extractant has a basic shape of the polymer resin. It is characterized in that it selectively separates only foreign substances that express color without transforming.

In addition, as an embodiment of the extractant, the colored polymer resin containing the ester functional group, the polymer resin alone containing the ester functional group; Or a polymer resin containing an ester functional group and a mixed resin further comprising at least one of polyethylene, polypropylene, polystyrene and polyvinyl chloride, cotton, hemp, wool, rayon, acetate, acrylic, nylon and spandex. do.

In addition, in another embodiment of the present invention, in the method of removing color-expressing foreign substances from the colored polymer resin containing an ester functional group, the extractant is heated at 70 ° C to 200 ° C to obtain a colored color containing an ester functional group. By directly contacting the polymer resin, it is characterized in that the color-expressing foreign matter is eluted from the colored polymer resin containing an ester functional group.

In addition, as one embodiment of a method of removing color-expressing foreign substances from the polymer resin, in the elution of color-expressing foreign substances from the colored polymer resin containing an ester functional group using the extractant, the dye is included. The extracted extraction mixture is heated, and the extractant vaporized from it is continuously refluxed and resupplied, and the refluxed liquid extractant is characterized in that it maintains continuous contact with the polymer resin containing the ester functional group.

In addition, as an embodiment of a method of removing foreign substances expressing color from the polymer resin, the extractant and the colored polymer resin containing the ester functional group are contacted at a temperature 0 to 50 ° C. lower than the boiling point of the extractant. characterized by

In addition, as an embodiment of a method of removing foreign substances that express color from the polymer resin, the extractant is directly contacted with the colored polymer resin containing an ester functional group to express color from the colored polymer resin containing an ester functional group. After eluting the foreign matter, it is characterized in that the extraction agent is recovered from the extraction mixture containing the extraction agent and the foreign matter expressing the color in a manner including at least one of evaporation and distillation.

In addition, as an embodiment of a method of removing foreign substances that express color from the polymer resin, the extractant is directly contacted with the colored polymer resin containing an ester functional group to express color from the colored polymer resin containing an ester functional group. It is characterized in that, after eluting the foreign substances, the polymer resin containing the bleached ester functional group is chemically depolymerized without a separate extractant separation process.

In addition, as an embodiment of a method of removing color-expressing foreign substances from the polymer resin, after depolymerizing the polymer resin containing the decolored ester functional group, the remaining color present in the product according to the depolymerization reaction is removed. It is characterized in that the expressed foreign substances are separated through a liquid-liquid extraction process.

In addition, as an embodiment of a method for removing color-expressing foreign substances from the polymer resin, the extractant may be added before or after the depolymerization reaction, and when the extractant is added before the depolymerization reaction, the added It is characterized in that the ratio of the total number of moles of the extractant including the extractant is 0.1 to 50 per mole of the repeating unit of the polymer resin.

In addition, as an embodiment of a method of removing a foreign substance exhibiting color from the polymer resin, the liquid-liquid extraction process is characterized in that it is performed at a temperature range of 25 to 150 ℃.

When the dye is removed from the colored polymer resin containing an ester functional group by using the extractant according to the present invention, the mutual attraction between the extractant and the polymer resin is stronger than the mutual attraction between the dye and the polymer resin, so that the dye is bonded with the polymer resin. It has the effect of lowering or hindering the mutual attraction of the dyes to remove the dyes from the colored polymer resin containing the ester functional group very quickly and effectively than the extractants reported by the prior art.

In addition, the extractant according to the present invention can interfere with the strong interaction that exists between the dye and the polymer, as described above, and regulates the non-covalent mutual attraction such as π-overlap between the aromatic rings of the dye and the additive, hydrogen bonding force, etc. can be used

In addition, since the extractant according to the present invention has a characteristic that does not participate in the chemical depolymerization reaction in the regeneration process of the polymer resin containing an ester functional group after the decolorization process using the extractant, the extractant from the polymer resin after the decolorization process There is an effect that can be directly applied to the depolymerization reaction without a separate process for separating the

In addition, the extractant according to the present invention can induce liquid-liquid phase separation with a hydrophilic solvent, which is a depolymerization reaction product, by lowering the temperature after the chemical depolymerization reaction in the regeneration process of the polymer resin containing an ester functional group after the decolorization process using the extractant. From the formed liquid-liquid phase equilibrium, a trace amount of dye not extracted in the direct contact process between the polymer resin and the extractant is concentrated in the organic phase, and the depolymerization product is concentrated in the aqueous solution layer, so that the dye is easily removed from the depolymerization product. It has a separable effect.

In addition, since the extractant according to the present invention does not cause serious physical and chemical transformation of the polymer resin containing an ester functional group, there is an effect that can be used in the production of physically regenerated materials for expressing colors differently.

In addition, when the extractant according to the present invention decolorizes a dye from a colored polymer resin containing an ester functional group, it is possible to quickly decolorize at a relatively low temperature, thereby reducing energy consumption, and extracting agent through a separate separation process. are mostly recoverable and reusable.

In addition, since the extractant according to the present invention uses a solvent with low harmfulness to the human body as an extractant, an environmentally friendly and economical purification process can be implemented.

In addition, the dye removal method using the extractant according to the present invention does not require complicated process units and can be directly introduced into the depolymerization reaction raw material without separating the extractant from the polymer containing the bleached ester functional group. There is an effect of providing a chemical regeneration method capable of completely removing unextracted residual dye.

In addition, even when the decolorizing polymer resin or depolymerization product obtained from the technology according to the present invention is reused as a raw material for plastic or resin products by repolymerization, there are no restrictions on quality and use, so that perfect chemical recycling technology can be implemented. .

Figure 1 shows the effect of an extractant according to an embodiment of the present invention, showing a fiber decolored by contact with a colored polyester fiber and an extractant (anisole).
Figure 2 shows the effect of the extractant according to an embodiment of the present invention, showing the degree of discoloration of polyester fibers according to the temperature of the extractant.
Figure 3 is to compare and explain the effect of the extractant and other extractants according to an embodiment in the present invention, and shows a comparison of the chemical structure of the used compound and the degree of decolorization of the fiber prepared by applying them.
4 is a photograph showing an example of phase separation occurring in the process of purifying a reaction mixture prepared according to an embodiment of the present invention.

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. In general, the nomenclature used herein is one well known and commonly used in the art.

Throughout this specification, when a certain component is said to "include", it means that it may further include other components without excluding other components unless otherwise stated.

Hereinafter, an extractant and method for removing color-expressing foreign substances from a colored polymer containing an ester functional group according to an embodiment of the present invention will be described in detail.

First, the extractant according to an embodiment of the present invention is an extractant for removing foreign substances expressing color from a colored polymer resin containing an ester functional group, comprising at least one compound represented by Formula 1 below. characterized by

In the compound represented by Formula 1 below, at least one alkyl group is connected to an aromatic ring through a linker, and the linker has at least one oxygen.

[Formula 1]

In Formula 1, R ₁ is any one selected from hydrogen, a hydroxyl group, an aldehyde group, a carboxyl group, a C ₁ -C ₆ alkyl group, a C ₄ -C ₆ cycloalkyl group, and a C ₆ -C ₁₂ aryl group, n is any one integer from 0 to 5, and when n is 2 or more, R ₁ are the same or different, R ₂ is a C ₁ -C ₁₀ alkyl group, and m is any one of 1 to 6 It is an integer of , and when m is 2 or more, -OR ₂ is each the same or different.

In one embodiment of the present invention, the compound represented by Formula 1 is methoxy benzene, 1,2-dimethoxybenzene, 1,3-dimethoxybenzene, 1,4-dimethoxybenzene, 1,2,3 -Trimethoxybenzene, 1,2,4-trimethoxybenzene, 1,3,5-trimethoxybenzene, 1,2,3,4-tetramethoxybenzene, 1,2,3,5-tetra Methoxybenzene, 1,2,4,5-tetramethoxybenzene, 2-methoxyphenol, 1,3-dimethoxy-2-hydroxybenzene, 4-hydroxy-3,5-dimethoxybenzoic acid, 3-(4-hydroxy-3,5-dimethoxyphenyl)prop-2-enal, 4-hydroxy-3,5-dimethoxybenzaldehyde, 4-hydroxy-3,5-dimethoxyaceto Phenone, 3-(4-hydroxy-3,5-dimethoxyphenylprop-2-enoic acid, 4-ethyl-2,6-dimethoxyphenol, 4-hydroxy-3-methoxybenzaldehyde, 3-hydroxy-4-methoxybenzaldehyde, 2-hydroxy-3-methoxybenzaldehyde, 2-hydroxy-5-methoxybenzaldehyde, 2-hydroxy-4-methoxybenzaldehyde Hyde, 3,4-dihydroxybenzaldehyde, 1-methoxy-4-[(E)-prop-1-enyl] benzene, 1-bromo-4-methoxybenzene, 2-tert-butyl -4-methoxyphenol, ethoxybenzene, phenol, 1,3,5-trichloro-2-methoxybenzene, 1,3,5-tribromo-2-methoxybenzene, 4-(prop- 2-en-1-yl) phenol, 1-methoxy-4 (prop-2-en-1-yl) benzene, 5- (prop-2-en-1-yl) -2H-1,3 - Benzodioxol, 4-methoxy-2-[(E)-prop-1-enyl]phenol, 2-methoxy-4-(prop-2-en-1-yl)phenol, etc. obtained from nature It may be at least one selected from the group consisting of known or synthesized compounds.

In addition, as an extractant for removing color-expressing foreign substances from the colored polymer resin containing an ester functional group according to the present invention, among the compounds represented by Formula 1, those present in a liquid phase having a melting point lower than the extraction temperature may be used, and the dye It is advantageous to have low viscosity and fluidity so that diffusion can occur quickly.

In addition, the extractant according to the present invention is useful as an extractant for removing foreign substances such as colored pigments and dyes from a colored polymer resin containing an ester functional group, wherein the polymer containing an ester functional group is used alone or in a mixed resin. In addition, at least one of a plastic material such as polyethylene, high density polyethylene, low density polyethylene, polypropylene, polystyrene, polyvinyl chloride, etc., or a fiber such as cotton, hemp, wool, rayon, acetate, acrylic, nylon, spandex, etc. It may be in the form of a mixed polymer resin containing the ester functional group included. For reference, other polymers mixed with the polymer containing the ester functional group listed as examples are only examples and are not limited to those listed above.

In addition, in another embodiment of the present invention, a method for removing color-expressing foreign substances from a colored polymer containing an ester functional group is to heat the extractant according to the present invention at 70 ° C to 200 ° C to group the ester functional group. It may be characterized by eluting the dye by directly contacting the containing colored polymer resin. The elution process may extract the dye through a single or repeated process.

The extraction temperature of foreign matter exhibiting color from the colored polymer resin containing the ester functional group may be carried out at 70 to 200 ° C, but more preferably at 120 to 150 ° C. If the temperature is less than 70 ℃, the elution rate proceeds slowly and the effect of extraction may be limited, and if the temperature exceeds 200 ℃, the energy consumption may be very high.

In addition, according to one embodiment of the present invention, in separating the dye from the colored polymer resin containing an ester functional group using the extractant, the extraction mixture solution containing the dye is heated and the extractant vaporized therefrom is continuously It is refluxed and resupplied, so that the refluxed liquid extractant maintains continuous contact with the polymer resin containing an ester functional group, so that a method of effectively removing the dyed dye can be applied.

In addition, in order to reflux only the extraction agent in the extraction mixture containing the dye, the temperature of the heating unit may be maintained at a temperature close to the boiling point of the extraction agent. The contact temperature (or extraction temperature) between the polymer and the extractant may be determined by the amount of heat applied to the heater and the reflux rate of the extractant, which may affect extraction performance. It may be desirable to proceed with the extraction so that the contact temperature between the polymer and the extractant is maintained or controlled at a temperature lower than the boiling point of the extractant by about 0 to 50 ° C.

On the other hand, after the extraction process is completed, the polymer resin containing the decolorized ester functional group may be in a state in which the extractant is absorbed, and the residual extractant may be separated by a method such as evaporation or drying to obtain a decolorized polymer resin product, The extraction mixture containing the dye can be subjected to an additional evaporation or distillation process to recover most of the initially applied extractant.

In addition, when the polymer resin containing the ester functional group, which is decolorized after the extraction process, is used as a raw material for chemical depolymerization (eg, glycolysis), the extractant is absorbed in the raw material form without going through the above separation process. Depolymerization may also be performed by introducing it into a chemical reactor. The extractant does not directly participate in the depolymerization reaction, and the type or amount added should not have an adverse effect on the performance of the depolymerization reaction, and it may be advantageous to not form a thermodynamically unstable phase under reaction conditions.

In addition, the present invention can provide a method for separating a small amount of unextracted residual dye in the reaction product through a liquid-liquid extraction process after chemical depolymerization of a polymer resin containing a bleached ester functional group. .

At this time, a hydrophilic solvent including water may be additionally added to the reaction product for efficient separation of the dye and recovery of the monomer product. It is characterized by the fact that most of them are distributed.

The amount of the extractant can be adjusted by adding it before and after the depolymerization reaction. However, when added before the depolymerization reaction, the total sum of the extractant including the added extractant is a ratio of 0.1 to 50 moles per mole of the repeating unit of the polymer, preferably. may be adjusted so that the number of moles is 1 to 5 per mole of the repeating unit. If the addition amount of the extractant is added in a ratio of less than 0.1 moles per mole of the repeating unit of the polymer, the boundary region of the liquid-liquid phase equilibrium is unclear after the reaction is completed, so that the residual dye cannot be extracted into the organic phase, and 50 per mole of the repeating unit of the polymer When added in a molar ratio exceeding , the performance of the depolymerization reaction may deteriorate due to excessive dilution of the reactants.

The liquid-liquid extraction process may be carried out while maintaining the temperature in the range of 25 to 150 °C, more preferably in the range of 50 to 100 °C.

In addition, in the present invention, in order to additionally remove dyes or residual organic foreign substances in the depolymerization reaction product prepared as described above, the liquid-liquid extraction process may be repeated by separating only the aqueous layer and then further adding the extractant. .

In addition, methods such as heating, drying, distillation, and evaporation may be used to separate and concentrate foreign substances such as dyes while recovering an extractant from the organic phase separated and discharged in the liquid-liquid extraction process.

Hereinafter, the details of the process of the present invention will be described through Examples, Comparative Examples and Experimental Examples. This is a representative example related to the present invention, and it is revealed that the scope of application of the present invention cannot be limited only by this.

colored polyester raw material

raw material 1

A non-woven polyester fiber fabric (supplier: Changsarang, average thickness: 0.13 mm) dyed in navy using a disperse dye was cut to prepare a colored fiber raw material having a square size of about 3 cm on one side.

raw material 2

A colored fiber raw material having a square size of about 3 cm on one side was prepared by cutting a plain polyester fiber fabric (average thickness: 0.13 mm) dyed in red using a disperse dye.

raw material 3

A colored fiber raw material having a square size of about 3 cm on one side was prepared by cutting a plain polyester fiber fabric (average thickness: 0.13 mm) dyed black using a disperse dye.

raw material 4

A colored fiber raw material having a square size of about 3 cm on one side was prepared by cutting a plain polyester fiber fabric (average thickness: 0.13 mm) dyed purple using a disperse dye.

raw material 5

A colored fiber raw material having a square size of about 3 cm on one side was prepared by cutting a plain polyester fiber fabric (average thickness: 0.13 mm) dyed green using a disperse dye.

raw material 6

A colored fiber raw material having a square size of about 3 cm on one side was prepared by cutting a plain polyester fiber fabric (average thickness: 0.13 mm) dyed brown using a disperse dye.

Polyester waste fiber raw material

raw material 7

A dark navy fleece jacket made of 100% polyester, which was discarded after consumption, was washed twice using a surfactant, and then washed using excess ethanol and distilled water, respectively. After drying the washed clothing until no residual moisture remains, it was cut into pieces with a side size of 1 cm or less to prepare waste fiber raw materials.

Examples 1 to 16 and Comparative Examples 1 to 4

: Color change of polyester fiber according to polyester fiber raw material, type of extractant and extraction temperature

Example 1

About 1.0 g of the navy polyester fiber of the above raw material 1 was put into a 250 ml flask containing 100.0 g of anisole (methoxybenzene) heated and maintained at 150 ° C in advance and stirred at 300 rpm using a magnetic stirrer for 10 g. After stirring for a minute, take out the polyester fiber using tweezers, wash it by dipping it in 10.0 g of anisole at the same temperature prepared in a 50 ml vial bottle for 1 to 2 seconds, transfer it to a glass evaporation dish, and vacuum (≤ 2 mmHg) and then placed in a vacuum dryer maintained at 60 ° C., and then dried for 12 hours or more to prepare a decolored fiber. The color coordinates L* a* b* values of the decolored fibers were measured using a spectrophotometer (manufacturer: Konica Minolta model name: CM-3700D). The value expressed as L* a* b* is the coordinate value of the color space standardized by the International Commission on Illumination (CIE), and L* is expressed as 0 (black) to 100 (white) representing lightness. It is a numerical value, and a* and b* are numerical values expressed along the complementary axes of red (100)/green (-100) and yellow (100)/blue (-100), respectively.

Example 2

A decolorized fiber was prepared in the same manner as in Example 1, except that the red fiber of Raw Material 2 was used as a raw material for polyester fiber, and the L* a* b* value was measured using a spectrophotometer. did

Example 3

A decolorized fiber was prepared in the same manner as in Example 1, except that the black fiber of raw material 3 was used as a raw material for polyester fiber, and the L* a* b* value was measured using a spectrophotometer. measured.

Example 4

A decolorized fiber was prepared in the same manner as in Example 1, except that the purple fiber of Raw Material 4 was used as a raw material for polyester fiber, and the L* a* b* value was measured using a spectrophotometer. did

Example 5

A decolorized fiber was prepared in the same manner as in Example 1, except that the green fiber of raw material 5 was used as a raw material for polyester fiber, and the L* a* b* value was measured using a spectrophotometer. did

Example 6

A decolorized fiber was prepared in the same manner as in Example 1, except that the brown fiber of Raw Material 6 was used as a raw material for polyester fiber, and the L* a* b* value was measured using a spectrophotometer. did

Comparative Example 1

A decolorized fiber was prepared in the same manner as in Example 1, except that the temperature of anisole, an extractant, was maintained at 50 ° C during the extraction and washing process, and the L* a* b* value was obtained using a spectrophotometer. was measured.

Example 7

A decolorized fiber was prepared in the same manner as in Example 1, except that the temperature of anisole, an extractant, was maintained at 70 ° C during the extraction and washing process, and the L* a* b* value was obtained using a spectrophotometer. was measured.

Example 8

A decolored fiber was prepared in the same manner as in Example 1, except that the temperature of anisole, an extractant, was maintained at 90 ° C during the extraction and washing process, and the L* a* b* value was obtained using a spectrophotometer. was measured.

Example 9

A decolorized fiber was prepared in the same manner as in Example 1, except that the temperature of anisole, an extractant, was maintained at 110 ° C during the extraction and washing process, and the L* a* b* value was obtained using a spectrophotometer. was measured.

Example 10

A decolored fiber was prepared in the same manner as in Example 1, except that the temperature of anisole, an extractant, was maintained at 130 ° C. in the extraction and washing process, and the L* a* b* value was obtained using a spectrophotometer. was measured.

Comparative Example 2

Except for using the red fiber of raw material 2 as the raw material of the polyester fiber, a decolorized fiber was prepared in the same manner as in Comparative Example 1, and the L* a* b* value was measured using a spectrophotometer. did

Example 11

A decolorized fiber was prepared in the same manner as in Example 7, except that the red fiber of raw material 2 was used as a raw material for polyester fiber, and the L* a* b* value was measured using a spectrophotometer. did

Example 12

A decolorized fiber was prepared in the same manner as in Example 8, except that the red fiber of Raw Material 2 was used as a raw material for polyester fiber, and the L* a* b* value was measured using a spectrophotometer. did

Example 13

A decolorized fiber was prepared in the same manner as in Example 9, except that the red fiber of Raw Material 2 was used as the raw material of the polyester fiber, and the L* a* b* value was measured using a spectrophotometer. did

Example 14

A decolorized fiber was prepared in the same manner as in Example 10, except that the red fiber of raw material 2 was used as the raw material of the polyester fiber, and the L* a* b* value was measured using a spectrophotometer. did

Comparative Example 3

A decolored fiber was prepared in the same manner as in Example 10, except that para-xylene was used instead of anisole as an extractant, and L* a* b* values were measured using a spectrophotometer. did

Comparative Example 4

A decolorized fiber was prepared in the same manner as in Example 10, except that methoxycyclohexane was used instead of anisole as an extractant, and the L* a* b* value was measured using a spectrophotometer. .

Example 15

A decolored fiber was prepared in the same manner as in Example 10, except that 1,2-dimethoxybenzene was used instead of anisole as an extractant, and L* a was used using a spectrophotometer. *b* values were measured.

Example 16

A decolored fiber was prepared in the same manner as in Example 10, except that 1,4-dimethoxybenzene was used instead of anisole as an extractant, and L* a was used using a spectrophotometer. *b* values were measured.

Example 17

A decolored fiber was prepared in the same manner as in Example 10, except that ethoxybenzene was used instead of anisole as an extractant, and L* a* b* values were measured using a spectrophotometer.

Example 18

A decolored fiber was prepared in the same manner as in Example 10, except that guaiacol was used instead of anisole as an extractant, and L* a* b* values were measured using a spectrophotometer.

Experiment 1: Measurement of color change of polyester fibers upon contact with an extractant

In the present invention, as a means for removing organic foreign matter including color from a colored polyester resin, it is represented by Formula 1 (at least one alkyl group connected to an aromatic ring through a linker, and the linker having at least one oxygen) Among these compounds, anisole (methoxybenzene) has the simplest structure.

In order to use these compounds as extractants to remove organic foreign substances present in the form of complexes in polymer substrates, sufficient energy to overcome the mutual bonding force formed by them in the presence of extractants must be secured, and extraction is one of the easiest methods. A method of increasing the contact temperature between the agent and the polymer may be used.

1 shows fibers decolored by contact with colored polyester fibers and an extractant (anisole) according to Examples 1 to 6 of the present invention, polyester fibers containing various colors (raw materials 1 to 6) As in the extraction conditions shown in Example 1, the color of the fibers (Examples 1 to 6) prepared by contacting with anisole heated to 150 ° C. to extract the dye.

As shown in FIG. 1, most of the dye in the fiber was extracted after contact with the anisole extractant, and it can be confirmed with the naked eye that all fibers are bright white, which is difficult to distinguish after decolorization, regardless of the color and contrast of the fiber starting material. could

primary color of fibers division L a b Indigo raw material 1 19.1 1.6 -9.5 Example 1 82.6 0.7 0.8 Red raw material 2 41.9 53.9 18.2 Example 2 82.7 0.2 1.0 Black color raw material 3 19.0 0.8 -0.9 Example 3 83.4 -0.2 2.3 purple raw material 4 66.9 7.0 -14.6 Example 4 83.6 -0.1 -0.4 green raw material 5 53.6 -42.8 18.1 Example 5 84.4 -1.5 1.5 brown raw material 6 33.9 12.2 12.3 Example 6 82.2 -1.6 -0.5

In addition, [Table 1] shows the results of Examples 1 to 6, and a spectrophotometer was used for the fibers bleached through contact with colored polyester fibers and heated anisole, and the measured L* a *b* values are shown in comparison with Table 1.

As shown in [Table 1], the lightness values measured by the spectrophotometer for the fibers decolored according to Examples 1 to 6 showed values of 82 to 85. This is the result of using the dark surface as the background for textile measurement and fabric characteristics of the fiber. Among the color coordinates, the values of a and b, which represent the complementary axes of red/green and yellow/blue, had very different values in the case of the primary colors of fibers, but tended to be measured as values very close to 0 in the fibers after decolorization.

As described above, when anisole was used as a dye extractant for the colored polyester resin under the conditions of Example 1, it was found to have a very good decoloring effect even with a very short contact time (10 minutes).

Experiment 2: Measurement of property change of polyester fiber according to extraction temperature

Figure 2 shows the degree of discoloration of polyester fibers according to the extractant temperature according to Examples 1, 2, 7 to 14 and Comparative Examples 1 to 2 of the present invention, the same indigo and red polyester fibers at different temperatures After contacting the retained extractant (anisole) for 10 minutes, it is shown by comparing the degree of discoloration of the fibers prepared through drying.

As shown in Figure 2, when decolorized through contact with the extractant maintained at a temperature of 50 ℃ (Comparative Example 1 and Comparative Example 2), almost no change in color was found when confirmed with the naked eye. On the other hand, it was observed that the color faded when contacted with an extractant maintained at a temperature of 70 ° C or higher, and it was found that many dyes were rejected when using an extractant maintained at a temperature of 100 ° C or higher. In particular, when the extractant temperature was applied at 130 ° C. or higher (Examples 1, 2, 10 and 14), it was found that almost no colored organic matter remained on the treated fibers.

primary color of fibers division extraction temperature
(℃) L a b Dye removal rate (%) Indigo raw material 1 - 19.1 1.6 -9.5 - Comparative Example 1 50 19.3 1.4 -9.8 1.5 Example 7 70 20.0 1.4 -11.6 6.4 Example 8 90 30.4 -1.6 -25.5 51.1 Example 9 110 70.5 -5.5 -11.3 97.5 Example 10 130 82.0 0.4 0.1 100.0 Example 1 150 82.6 0.7 0.8 100.0 Red raw material 2 - 41.9 53.9 18.2 - Comparative Example 2 50 41.8 54.2 19.5 0.8 Example 11 70 43.5 55.9 19.6 5.6 Example 12 90 48.0 52.9 14.1 46.4 Example 13 110 77.0 10.8 0.6 96.8 Example 14 130 82.5 0.9 0.9 100.0 Example 2 150 82.7 0.2 1.0 100.0

[Table 2] shows the results of Examples 1, 2, 7 to 14 and Comparative Examples 1 to 2 of the present invention, and the color of each of the decolorized polyester fibers shown in FIG. 2 was measured using a spectrophotometer. Changes are measured and compared with color coordinates (L* a* b*) values.

As shown in [Table 2], in the case of fibers treated through contact with an extractant maintained at a low temperature of 50 ° C. or less, it was observed that no significant difference occurred in the values of L * a * b *.

In addition, when the fiber is in contact with the extractant maintained at a temperature range of 50° C. to 100° C., a gradual change in L* a* b* value indicating partial discoloration was observed.

In addition, when the temperature of the extractant used to extract the dye from the colored polyester resin exceeded 100 ° C, not only the value of lightness (L) increased significantly regardless of the raw material, but also the values of a and b representing the complementary axis were also positive or negative. Approaching the neutral value with no significant negative deviation was observed.

On the other hand, in [Table 2], the dye removal rate of the decolorized fiber according to the extraction temperature was calculated from the relative absorbance measured using a UV-visible spectrometer. A sample for measuring chromaticity (dye concentration = C _s ) was prepared by mixing and taking a portion of the extraction solution containing the dye obtained after extraction, and then diluting it 5 times with pre-quantified anisole, and the length of the penetration path (path length) was 10 mm After transferring to a cuvette, the absorbance ( A _s ) for each sample was measured at the wavelength at which maximum absorption occurs (λ _max ; 600 nm for the extract of raw material 1 and 512 nm for the extract of raw material 2) using a UV-visible spectrometer. measured. The maximum amount of dye that can be extracted from the fiber is the total extraction solution obtained after repeating the process of extracting by contacting anisole at 150 ° C. (Example 1 or Example 2) three times by applying the same mass of colored fiber as a raw material. Absorbance ₍ A _∞ ) was used as the standard.

The dye removal rate ( R ) of decolorized fibers according to the extraction temperature in [Table 2] can be calculated from the following equation using the absorbance values measured for each sample.

R (%) = ( C _∞ - C _s )/ C _∞ ×100 = ( A _∞ - A _s )/ A _∞ ×100

As shown in [Table 2], as a result of the dye removal rate calculation, when the temperature of the extractant for dye removal was maintained at 70 ° C. or higher and contacted, it was found that the dye was excluded from the colored polyester resin. It was found that the dominant extraction effect was expressed when using an extractant maintained at a temperature of 100 ° C or higher, and when using an extractant maintained at a temperature of 130 ° C or higher, most dye removal was achieved with a relatively short contact time (10 minutes). it was possible

Experiment 3: Measurement of dye removal effect according to extractant type

Next, when the type of extractant according to the present invention was modified through Examples 10, 15 to 18 and Comparative Examples 3 to 4, the degree of removal of colored foreign substances from colored polyester fibers was observed and extracted therefrom. I would like to compare and explain the effect of the offer.

As in Examples 10, 15 to 18 and Comparative Examples 3 to 4, the same conditions were applied except for the extractant so that the decolorization effect by different extractants could be easily distinguished. The temperature of the extractant was kept constant at 130 ° C, and the blue polyester fiber of Raw Material 1 was used as a polymer for decolorization.

Figure 3 is to compare and explain the effect of the extractant and other extractants according to an embodiment in the present invention, and shows a comparison of the chemical structure of the used compound and the degree of decolorization of the fiber prepared by applying them. The temperature of the extractant was kept constant at 130 ° C, and the blue polyester fiber of Raw Material 1 was used as a polymer for decolorization.

In addition, the following [Table 3] shows a comparison of color coordinate (L* a* b*) values measured using a spectrophotometer for each of the manufactured decolorized polyester fibers.

division extractant type L a b raw material 1 - 19.1 1.6 -9.5 Comparative Example 3 p-Xylene 54.5 -7.1 -21.0 Example 10 Anisole 82.6 0.7 0.8 Example 15 1,2-Dimethoxybenzene 77.6 -1.7 -2.9 Example 16 1,4-Dimethoxybenzene 79.7 0.0 -0.1 Example 17 Ethoxybenzene 71.5 -4.9 -10.1 Example 18 Guaicol 84.0 0.6 0.3 Comparative Example 4 Methoxycyclohexane 30.0 -2.0 -24.5

For reference, in some prior patents (US 7959807B2, US 2015/0059103A1), it is known that aromatic compounds such as paraxylene are useful as extractants for removing dyes from colored polyester resins. Paraxylene is a relatively stable non-polar hydrocarbon compound with a boiling point of about 138°C. Under the above-described extraction conditions, when paraxylene was applied as an extractant and decolorization was performed through contact with colored polyester fibers (Comparative Example 3), some partial discoloration was observed, but the remaining amount of dye could not be easily distinguished with the naked eye. could When measured using a spectrophotometer for the polyester fiber decolored by paraxylene, the lightness (L) showed a value of 55 or less, and the values of a and b, which represent the complementary color axis for color, were also large from the neutral value. Negative deviations (green and blue) were observed.

On the other hand, when the extractant presented in the present invention, that is, the extractant represented by Formula 1 (at least one alkyl group connected to an aromatic ring through a linker, and the linker having at least one oxygen) is used (Examples 10 and 15 to 18), very high dye extraction effects were observed under the same conditions.

In addition, the lightness (L) values measured by the spectrophotometer for the decolorized polyester fibers prepared through the extractant having the chemical form presented in the present invention all showed values of 70 or more, indicating the complementary color axis for color. The values of a and b were also mostly measured close to neutral values.

In addition, when 1,2-dimethoxybenzene (Example 15) and ethoxybenzene (Example 17) were applied among the examples for the extractant according to the present invention, the effect of decolorization was observed to be somewhat low, but the alkoxy group It is presumed that this is due to the steric hindrance of the compound structure resulting from the position and number of carbon atoms bonded to the aromatic ring.

Methoxycyclohexane has a structure similar to that of the additive according to the present invention, but is a compound modified with a saturated cycloalkane having the same number of carbon atoms as the aromatic ring, which is the central functional group of the compound. When this was applied under the same extraction conditions (Comparative Example 4), as shown in FIG. Looking at the color coordinates (L* a* b*) values measured from the spectrophotometer for the fibers manufactured by Raw Material 1 and Comparative Example 4 used, the coordinates shifted, but the color coordinate space occurred when decolorization proceeded. There was no significant vertical rise of the L value or a significant shift in the direction of the neutral value of the a and b values. Therefore, it can be seen that compounds other than the aromatic ring, which is the central functional group of the compound, have very little effect as an extractant.

Examples 19 to 22: Continuous dye extraction from polyester fiber raw materials

Example 19

About 6.0 g of navy polyester fiber of raw material 1 is put on a cylindrical filter paper (Whatman; pore size 10㎛) and put into a Soxhlet extractor with a volume of 250 ml, and a condenser for solvent reflux is connected to the top of the extractor. And at the bottom, a 500 ml round bottom flask filled with 250 g of anisole was connected, and the bottom flask was placed in a magnetic stirrer with a block heater and heated simultaneously with stirring (500 rpm). Extraction was performed for 1 hour from the point at which the anisole in the flask reached the boiling point, and the dye was continuously extracted into the flask. In order to observe the speed of extraction during the extraction process, about 0.3 ml of the mixed solution in the Soxhlet extractor and the flask was taken at intervals of 2.5 minutes, and then diluted 5 times with pre-quantified anisole to prepare a sample for measuring chromaticity, After transferring to a cuvette with a path length of 10 mm, a UV-Vis spectrophotometer (manufacturer: Thermo Scientific model name: GENESYS 180) was used for each sample at the wavelength at which maximum absorption occurs. Relative absorbance was measured. When the extraction time has elapsed 1 hour, the fibers are separated from the Soxhlet extractor, transferred to a glass evaporation dish, placed in a vacuum dryer maintained at 60° C. under vacuum (≤ 2 mmHg), and then dried for more than 12 hours to obtain a decolored product. After recovering the fiber, its weight was quantified using a high-precision balance. The decolored fibers were measured for L* a* b* values using a spectrophotometer.

Example 20

A bleached fiber was prepared in the same manner as in Example 19, except that the red fiber of Raw Material 2 was used as a raw material for polyester fiber. * Values were measured.

Example 21

A decolorized fiber was prepared in the same manner as in Example 19, except that the black fiber of Raw Material 3 was used as the raw material of the polyester fiber. The decolored fibers were measured for L* a* b* values using a spectrophotometer.

Example 22

A decolorized fiber was prepared in the same manner as in Example 19, except that the brown fiber of Raw Material 6 was used as a raw material for the polyester fiber. The decolored fibers were measured for L* a* b* values using a spectrophotometer.

Experiment 4: Results of continuous extraction of dyes using a Soxhlet extractor

In general, since most of the substances (dyes or pigments) added to give color to the polyester polymer resin have a high boiling point, only the extractant is vaporized from the mixed solution discharged in the state in which foreign substances are extracted, and the color to be treated By inducing re-contact or continuous contact with fibers, extraction performance can be improved using a limited amount of solvent, which can be applied to a continuous treatment process for decolorizing a large amount of raw materials.

In Examples 19 to 22, in order to observe the effect of decolorization by continuous extraction, decolorization of colored polyester fibers was performed using a Soxhlet extractor. The temperature of the heating part was adjusted to be maintained at or above the boiling point of the extractant so that only the extractant was refluxed from the mixed solution (including foreign matter and extractant) discharged during the extraction process so that re-contact with the fiber occurred continuously. During the extraction process, the temperature in the Soxhlet extractor was maintained at 125 to 135°C.

In the extraction process, the solution in the Soxhlet extractor and a portion of the solution in the heating flask are taken at intervals (2.5 minute intervals), and for a solution diluted 5 times with anisole, the wavelength at which maximum absorption occurs (λ _max ; raw material) 1 at 600 nm, raw material 2 at 512 nm, raw material 3 at 577 nm, and raw material 6 at 464 nm) to measure the time point at which dye extraction predominantly occurs.

As a result of the measurement, the time at which most dyes were removed was slightly different depending on the raw material, and was determined by the time and number of times the extraction solution was flushed from the Soxhlet extractor. In the case of the reddish fiber (raw material 2), most of the dye was removed after the extraction solution was discharged twice. In the case of 6), most of the dye was removed after the extraction solution was discharged three times.

Before extraction (m ₀ ) After extraction (m) division start
Raw material L a b L a b weight change,
Δ(%) Example 19 Raw material 1 (dark blue) 19.1 1.6 -9.5 82.7 0.2 1.2 2.5 Example 20 Raw material 2 (red) 41.9 53.9 18.2 82.3 0.1 0.7 3.0 Example 21 raw material 3 (black) 19.0 0.8 -0.9 83.5 -0.1 1.9 2.8 Example 22 Raw material 6 (brown) 33.9 12.2 12.3 81.4 -1.1 -0.8 2.0 Weight change: mass reduction rate of fiber according to dye removal [Δ=(m ₀ -m)/m ₀ × 100 (%)]

[Table 4] shows the color coordinate values measured for decolorized polyester fibers manufactured by using colored polyester fibers as raw materials and applying the condition that the extraction solution in the Soxhlet extractor is discharged at least 3 times within 1 hour. (L* a* b*) shows the change in weight.

As shown in [Table 4], the lightness (L) value measured by the spectrophotometer showed a value of 80 or more in all cases, and the absolute value of a and b values representing the complementary color axis for color was 2. measured at very small values that do not exceed

On the other hand, the amount of foreign matter including dyes dyed in the colored polyester fiber could be estimated by the weight loss of the fiber before and after extraction, and was measured as a mass corresponding to about 2 to 3% of the total weight of the colored fiber.

Examples 23 to 24 and Comparative Example 5: Polyester Fiber Depolymerization

Comparative Example 5

(a) Depolymerization reaction: About 10 g of raw material 7 prepared from waste navy polyester fibers and about 38.8 g of ethylene glycol, a dihydric alcohol polar solvent, were put into a 3-neck flask, and a reflux condenser was installed at atmospheric pressure. Stirring was started using a magnetic stirrer.

When the reaction mixture reached 197 ° C or the reflux temperature, about 0.114 g of zinc acetate catalyst was added to initiate the catalytic reaction, and the reaction mixture was continuously stirred for 2 hours while the reaction temperature was kept constant within ± 1 ° C. The reaction was carried out using a condenser exposed to

At the end of the reaction, a small amount of the reaction mixture was taken and prepared as a sample for quantification. The reaction yield of the depolymerized monomer and dimer was measured using high-performance liquid chromatography (HPLC with C18 column, UV detector (λ=254 nm)) calibrated with each standard sample.

As a mobile phase for HPLC analysis, a mixed solution with a volume ratio of methanol:water of 70:30 was used, and the total flow rate was maintained at 0.7 ml/min. All reaction mixtures, except for a small amount of samples taken for quantification, were filtered using a cellulose acetate filter paper (pore size: 0.45 μm). On the filter paper, solid compounds other than monomers, such as dimers, oligomers, and unreacted polymers, and some dyes were obtained as solid content.

The yield of the products in the reactants was calculated by the following equation.

- Yield of monomer, Y _BHET (%) = M _BHET / M ₀ × 100

- Yield of dimer, Y _Dimer (%) = M _Dimer /M ₀ × 100

- Yield of oligomer, Y _Oligomer (%) = M _Oligomer /M ₀ × 100

- Yield of by-product (MHET), Y _MHET (%) = M _MHET /M ₀ × 100

Here, M _BHET , M _Dimer , M _Oligomer , and M _MHET represent the number of moles of BHET, dimer, oligomer, and MHET determined by HPLC, respectively, and M ₀ represents the number of moles of repeating units in the input polymer structure.

(b) Recovery of depolymerization products: After leaving the reaction mixture solution containing the monomers or the aqueous phase extracted in Experimental Example 3 or Experimental Example 4 in a storage chamber maintained at 4° C. for 12 hours, the crystallized solid phase was physically filtered. After removing a large amount of moisture using the method, it was taken as a solid content.

This was again transferred to a vacuum dryer maintained at 60° C. and vacuum dried for 12 hours or more to obtain a depolymerization product (BHET) containing dye as an impurity.

(c) Depolymerization product chromaticity measurement: After taking about 200 mg of the obtained BHET, a 13 mm disc was spectroscopically analyzed using a pellet manufacturing mold (Pike Evacuable KBr Die Kit) and a hydraulic press (Hydraulic Press, Pike CrushIR) (applied pressure: 10 tons). It was prepared as a sample for colorimetric measurement.

For the analysis of the sample, the L* a* b* value of the sample was measured using the spectrophotometer described in Example 1.

Example 23

As in the method of Example 9, the navy polyester fiber raw material of raw material 7 was directly contacted with anisole maintained at a temperature of 110 ° C. for 10 minutes to extract the dye, and using anisole at the same temperature After washing once, 10 g of partially bleached fibers through vacuum drying were prepared as a raw material for depolymerization.

This was subjected to depolymerization and product recovery in the same manner as in Comparative Example 5 to obtain a BHET product, and L* a* b* values were measured using a spectrophotometer.

Example 24

As in the method of Example 9, the navy polyester fiber raw material of raw material 7 was directly contacted with anisole maintained at a temperature of 110 ° C. for 10 minutes to extract the dye, and using anisole at the same temperature as 1 A decolorized fiber that was not subjected to a drying process after being washed twice was prepared. From this, fibers corresponding to 10 g based on the weight of the decolorized fibers were taken as raw materials for the depolymerization reaction and put into a 3-neck flask together with ethylene glycol, and the total amount of anisole (methoxybenzene) was about 22.5 g. The reactants were prepared by adding as much as possible. When the reaction mixture was heated to reach the reflux temperature, the reaction was carried out in the same manner as in the depolymerization method of Comparative Example 5 (a), except that about 0.20 g of potassium acetate catalyst was added to initiate the catalytic reaction.

After completion of the reaction, about 200 g of distilled water at 95 to 100 ° C. was added to the filtrate obtained from the filtration. Thereafter, the mixture was transferred to a container maintained at a constant temperature of 75° C. and stirred, and the stirring was stopped after 1 hour to induce phase separation. After separating only the aqueous layer from the organic layer containing most of the dye and extractant, a BHET product was obtained through the same depolymerization product recovery method as in Comparative Example 5 (b), and the same method as in Comparative Example 5 (c) was applied. Pellets were prepared using a spectrophotometer, and L* a* b* values were measured.

Experiment 5: Comparison of chemical depolymerization reaction and product quality

In the above-described examples, an effective method for removing colored foreign substances from colored polyester raw materials by applying the extractant according to the present invention has been described. A polymer resin containing an ester bond from which color-expressing foreign substances are removed may be suitably used as a raw material for physical or chemical regeneration.

The following examples show a case where the colored polyester raw material itself is subjected to a generally known depolymerization reaction (glycolesis using a zinc acetate catalyst) (Comparative Example 5), partially decolorized polyester according to an example of the extraction method described above. When the ester raw material was applied to the same depolymerization reaction (Example 23) and when the raw material containing the extractant was added to the depolymerization reaction and the dye was additionally removed in the purification process (Example 24), the characteristics of the reaction that can proceed by each and to compare the quality of the final product that can be manufactured.

The performance of the reaction evaluated by quantitative analysis of the product after the depolymerization reaction and the color coordinate values (L* a* b*) measured using a spectrophotometer after pelletizing the prepared monomer are shown in [Table 6] below.

As the low-density polymer was applied as a raw material, depolymerization proceeded very rapidly in all cases, and it was observed that all fibers were decomposed within 30 minutes (conversion rate = 100%), but left for sufficient reaction time (2 hours). This allowed the reaction equilibrium to be reached.

division reaction
temperature Depolymerization reaction yield (%) Color coordinate values for monomers BHET dimer oligomer MHET L a b Comparative Example 5 197℃ 83.6 4.9 10.3 1.3 51.3 18.8 19.7 Example 23 197℃ 85.2 4.8 8.5 1.5 64.3 15.3 18.2 Example 24 153℃ 86.7 4.8 7.1 1.4 94.6 -0.2 0.4

In Comparative Example 5 to compare and explain the effects of the embodiments of the present invention, a dark navy polyester waste fiber raw material that had not undergone a bleaching process by an extractant was directly applied to the glycolysis reaction. The most commonly used zinc acetate catalyst was added to initiate the reaction at the reflux temperature of ethylene glycol (197° C.), and when the final reaction time was reached, it was determined that about 83.6% of BHET could be obtained.

The BHET product obtained in Comparative Example 5 showed a color completely different from that of the navy polyester fiber, which was the starting material, and the lightness (L) was about 51 , the values of a and b representing the complementary color axis were measured as positive values close to 20. This indicates that the dye, which is an impurity that develops color, is not easily removed in the purification process (physical filtration and recrystallization) of the product.

In Example 23, depolymerization was performed in the same manner as in Comparative Example 5, but decolorization polyester fiber in which some of the impurities were removed in advance through contact with anisole maintained at 110 ° C. for 10 minutes according to the extraction and washing process of Example 9. was applied as a raw material.

In Example 23, after 2 hours of depolymerization, the yield of BHET was measured to be 85.2%, which was slightly higher than that of Comparative Example 5. The color of the BHET prepared through the purification process became pale, but a high level of color was still observed due to residual foreign substances that were difficult to remove during the purification process. In the color coordinate values measured by a spectrophotometer after pelletizing, the brightness is about 64, and the a and b values representing the complementary color axis are about 15 and 18, which are slightly lower than those of the raw material without pretreatment (Comparative Example 5) Measured.

In Example 24, in the process of removing the color-expressing material using the extractant, the extractant was not removed and the amount was adjusted and applied to the depolymerization reaction. Reflux of the extractant (anisole) added to the reaction was carried out at a low temperature possible.

In Example 24, after 2 hours of depolymerization reaction, about 87% of BHET was obtained, which is higher than the previous two cases. After separating high molecular weight substances such as dimers and oligomers from the reactants obtained from depolymerization through physical filtration, adding water to purify the monomers, and lowering the temperature of the mixture to 100 ° C or less, thermodynamically unstable phase separation occurred. When the boundary regions of the phases were clear, it was easy to see that the residual dye was distributed in high concentration in the upper layer (organic phase layer), which is the main constituent of the extractant. The asymmetric distribution of the dye was visually identifiable, and an example of phase separation occurring during the purification process of the reaction mixture prepared according to the process of Example 24 is shown in FIG. 4 .

After taking the aqueous phase obtained by separating the organic phase in which the color-expressing substance is highly concentrated, it is left at low temperature (4 ℃) for a long time to proceed with the crystallization of the monomer, and after recovering it, it is dried to obtain high-purity BHET with a white color. Could. When the BHET obtained from the extraction process is contaminated by a color-expressing substance, a small amount of the extractant and water heated to 90 ° C. or higher are added again in a similar ratio to obtain a high-purity product, and the liquid-liquid extraction described above Most of the remaining foreign matter can be removed very effectively by using the method of repeating the process of

The obtained white BHET was manufactured into pellets and measured with a spectrophotometer. As a result, the brightness was close to about 95, and the a and b values were measured as samples having a color close to pure white with an absolute value of 0.5 or less.

When the series of procedures shown in Example 24 are applied to a commercial process for chemical regeneration of colored polyester, polyester polymer resin from which many color-expressing foreign substances have been removed through pretreatment can be applied as a raw material for depolymerization reaction, It is directly applied as a raw material in the chemical regeneration process without removing a separate extractant, so that the depolymerization reaction can be performed without reducing the yield, and after the reaction is completed, color-developing foreign substances can be effectively removed, so it is very economical to drastically lower the purification cost. It is expected that the phosphorus monomer manufacturing process can be implemented.

Having described specific parts of the present invention in detail above, it will be clear to those skilled in the art that these specific descriptions are only preferred embodiments, and the scope of the present invention is not limited thereby. . Accordingly, the substantial scope of the present invention will be defined by the appended claims and their equivalents.

Claims (12)

A material used for extraction to remove color-expressing foreign substances from a colored polymer resin containing an ester functional group and to improve the performance of the depolymerization reaction of the resin,
The material is used for extraction of a foreign material expressing a color from a colored polymer resin containing an ester functional group, characterized in that it comprises a compound represented by Formula 1 below, and then used for extraction of a colored polymer resin containing the ester functional group without separation. A material characterized in that it is used for depolymerization as it is and improves depolymerization reaction performance.
[Formula 1]

(In Formula 1, R ₁ is any one selected from hydrogen, a hydroxy group, an aldehyde group, a carboxyl group, a C ₁ -C ₆ alkyl group, a C ₄ -C ₆ cycloalkyl group, and a C ₆ -C ₁₂ aryl group, n is any one integer from 0 to 5, and when n is 2 or more, R ₁ are the same or different, R ₂ is a C ₁ -C ₁₀ alkyl group, and m is any one of 1 to 6 It is an integer of, and when m is 2 or more, -OR ₂ are each the same or different.)
According to claim 1,
The compound represented by Formula 1 is methoxybenzene, 1,2-dimethoxybenzene, 1,3-dimethoxybenzene, 1,4-dimethoxybenzene, 1,2,3-trimethoxybenzene, 1,2 ,4-trimethoxybenzene, 1,3,5-trimethoxybenzene, 1,2,3,4-tetramethoxybenzene, 1,2,3,5-tetramethoxybenzene, 1,2,4 ,5-tetramethoxybenzene, 2-methoxyphenol, 1,3-dimethoxy-2-hydroxybenzene, 4-hydroxy-3,5-dimethoxybenzoic acid, 3-(4-hydroxy-3 ,5-dimethoxyphenyl) prop-2-enal, 4-hydroxy-3,5-dimethoxybenzaldehyde, 4-hydroxy-3,5-dimethoxyacetophenone, 3-(4-hydroxy -3,5-dimethoxyphenyl prop-2-enoic acid, 4-ethyl-2,6-dimethoxyphenol, 4-hydroxy-3-methoxybenzaldehyde, 3-hydroxy-4-methoxy Benzaldehyde, 2-hydroxy-3-methoxybenzaldehyde, 2-hydroxy-5-methoxybenzaldehyde, 2-hydroxy-4-methoxybenzaldehyde, 3,4-dihydroxy Benzaldehyde, 1-methoxy-4-[(E)-prop-1-enyl]benzene, 1-bromo-4-methoxybenzene, 2-tert-butyl-4-methoxyphenol, ethoxy Benzene, 1,3,5-trichloro-2-methoxybenzene, 1,3,5-tribromo-2-methoxybenzene, 4-(prop-2-en-1-yl)phenol, 1 -Methoxy-4-(prop-2-en-1-yl)benzene, 5-(prop-2-en-1-yl)-2H-1,3-benzodioxole, 4-methoxy- 2-[(E)-prop-1-enyl] phenol, 2-methoxy-4-(prop-2-en-1-yl) phenol, characterized in that at least one selected from the group consisting of, ester functional group A material characterized in that it improves depolymerization reaction performance by being used as it is for depolymerization of the colored polymer resin containing the ester functional group without separation after being used for extraction of color-expressing foreign substances from the colored polymer resin containing.
According to claim 1,
The colored polymer resin containing the ester functional group is a polymer resin that is colored by a foreign substance expressing one or more colors, and the material used for the extraction and improvement of the depolymerization reaction performance of the resin has a basic shape of the polymer resin. Colored polymer containing the ester functional group without separation after being used for extraction of foreign matter expressing color from a colored polymer resin containing an ester functional group, characterized in that it selectively separates only foreign substances expressing color without transforming the A material characterized in that it is used for depolymerization of a resin and improves depolymerization reaction performance.
According to claim 1,
The colored polymer resin containing the ester functional group is a polymer resin alone containing the ester functional group; Or a polymer resin containing an ester functional group and a mixed resin further comprising at least one of polyethylene, polypropylene, polystyrene and polyvinyl chloride, cotton, hemp, wool, rayon, acetate, acrylic, nylon and spandex. The material used for the extraction and improvement of the depolymerization reaction performance of the resin is used for extraction of a foreign material expressing color from the colored polymer resin containing the ester functional group, and then the colored polymer resin containing the ester functional group without separation. A material characterized in that it is used for depolymerization as it is and improves depolymerization reaction performance.
It is used for the extraction of color-expressing foreign substances from the colored polymer resin containing the ester functional group of any one of claims 1 to 4, and then used as it is for depolymerization of the colored polymer resin containing the ester functional group without separation, resulting in a depolymerization reaction. By heating a material characterized by improving performance at 70 ° C to 200 ° C and directly contacting a colored polymer resin containing an ester functional group,
After eluting the color-expressing foreign matter from the colored polymer resin containing the ester functional group,
Characterized in that the polymer resin containing the decolorized ester functional group and the material are subjected to chemical depolymerization as raw materials for depolymerization without a separate separation process.
Method for depolymerizing colored polymer resins containing ester functional groups.
According to claim 5,
After being used for the extraction of color-expressing foreign substances from the colored polymer resin, it is used as it is for depolymerization of the colored polymer resin containing the ester functional group without separation, thereby improving the performance of the depolymerization reaction. The colored polymer containing the ester functional group is used In the elution of color-expressing foreign substances from the resin, the extraction mixture solution containing the dye is heated and used for extraction of color-expressing foreign substances from the colored polymer resin vaporized therefrom, and then the ester functional group is removed without separation. A substance that is used as it is for depolymerization of the colored polymer resin and improves the performance of the depolymerization reaction is continuously refluxed and resupplied, and is used for extracting foreign substances that exhibit color from the colored polymer resin in the refluxed liquid state, and then the material without separation. A colored polymer resin containing an ester functional group, characterized in that it is used as it is for depolymerization of the colored polymer resin containing an ester functional group so that a material improving the depolymerization reaction performance is maintained in continuous contact with the polymer resin containing an ester functional group. Depolymerization method.
According to claim 5,
After being used for extraction of color-expressing foreign substances from the colored polymer resin, it is used as it is for depolymerization of the colored polymer resin containing the ester functional group without separation, at a temperature 0 to 50 ° C. lower than the boiling point of the material that improves the depolymerization reaction performance. , After being used for extraction of color-expressing foreign substances from the colored polymer resin, it is used as it is for depolymerization of the colored polymer resin containing the ester functional group without separation, thereby improving the performance of the depolymerization reaction and the colored polymer containing the ester functional group A method for depolymerizing a colored polymer resin containing an ester functional group, characterized in that the resin is contacted.
delete delete According to claim 5,
After depolymerization of the polymer resin containing the decolorized ester functional group,
A method for depolymerizing a colored polymer resin containing an ester functional group, characterized in that the color-expressing foreign matter remaining in the product following the depolymerization reaction is separated through a liquid-liquid extraction process.
According to claim 5,
Before or after the depolymerization reaction, it is used for the extraction of color-expressing foreign substances from the colored polymer resin, and then used as it is for depolymerization of the colored polymer resin containing the ester functional group without separation, so that a substance improving the depolymerization reaction performance can be added. there is,
In the case of adding a substance that improves depolymerization reaction performance by being used for depolymerization of the colored polymer resin containing the ester functional group without separation after being used for extraction of color-expressing foreign substances from the colored polymer resin before the depolymerization reaction, A method for depolymerizing a colored polymer resin containing an ester functional group, characterized in that the ratio of the total sum of the materials, including the material, is 0.1 to 50 moles per mole of the repeating unit of the polymer resin.
According to claim 10,
The liquid-liquid extraction process,
A method for depolymerizing a colored polymer resin containing an ester functional group, characterized in that it is carried out at a temperature range of 25 to 150 ° C.

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