TW202222766A - Method for purifying bis-2-hydroxyethyl terephthalate and polyester resin containing the same - Google Patents

Abstract

The present disclosure relates to a method for purifying bis-2-hydroxyethyl terephthalate with high purity and a polyester resin containing the same.

Description

Method for purifying bis-2-hydroxyethyl terephthalate (BIS-2-HYDROXYETHYL TEREPHTHALATE) and polyester resin containing the bis-2-hydroxyethyl terephthalate

Field of Invention

The present disclosure relates to a method for purifying high-purity bis-2-hydroxyethyl terephthalate and a polyester resin containing the bis-2-hydroxyethyl terephthalate.

Background of the Invention

Polyethylene terephthalate (PET) can be recycled after use, and the recycling methods are mainly divided into physical recycling and chemical recycling. Physical recycling is washing PET and then pulverizing it into large particles or flakes for use, and chemical recycling is recycling PET monomer by chemical reaction. In chemical recycling, PET is decomposed into monomers by a chemical reaction, and the resulting monomers can be reused as raw materials for polyester production. The monomers produced by decomposition have the same chemical properties as the monomers used in the initial polymer synthesis.

PET can be prepared by the condensation of terephthalic acid (TPA) with ethylene glycol (EG) or by the reaction of dimethyl terephthalate (DMT) with EG. Both methods revolve around the polymerization to PET via the PET monomer bis(2-hydroxyethyl) terephthalate (BHET). In PET recycling, monomer BHET can be obtained by depolymerization of PET and EG. After separation and purification of the by-products from the depolymerization reaction, the BHET obtained from the depolymerization reaction can be used again for PET polymerization.

US Patent No. 9127136 attempts to separate and purify BHET by liquid chromatography using a mixed solvent of methanol and water. However, when the mixed solvent is used in the separation and purification process, there may be difficulties in the recovery process of the mixed solvent. Additionally, US Patent Nos. 3,120,560 and 3,268,575 use water, dichloroethane, hexanol, and the like as crystallization solvents for BHET purification. However, when dichloroethane is used as a solvent, crystallization occurs at a high temperature of 70°C or higher, and separation at a high temperature is required. Additionally, US Pat. No. 3,632,830 attempted purification by BHET crystallization using aromatic solvents such as benzene, toluene, and xylene. European Patent Publication No. EP0723951 attempts to purify BHET by crystallizing BHET obtained by filtration after depolymerization of PET.

Japanese Patent Laid-Open No. 2000-169623 discloses a BHET crystallization and purification method using ethylene glycol, but it is difficult to completely remove by-products, and the recycled polyester produced by this method will produce discolored low-quality polyester. In addition, Japanese Patent Laid-Open No. 2008-088096, No. 2000-053802, No. 2016-536291 etc. disclose the purification of BHET obtained by depolymerization of PET, but there are the following problems: purified BHET and production using the BHET The polyester has unsatisfactory color quality.

Therefore, when using conventional crystallization solvents in the process of purifying BHET by crystallization, the present inventors faced limitations in removing impurities in BHET and thus improving color, and continued intensive research. Therefore, it has been confirmed that when a single solvent, especially ethanol, is used as a crystallization solvent, it is possible to improve the color of purified BHET and polyester prepared by using purified BHET as a recovered raw material, thereby completing the present invention.

Summary of Invention [ Technical Problem]

In the present disclosure, a method for purifying high-purity bis-2-hydroxyethyl terephthalate and a polyester resin containing the bis-2-hydroxyethyl terephthalate are provided. [ Technical Solutions]

In order to solve the above problems, a method for purifying bis-2-hydroxyethyl terephthalate is provided, which comprises the following steps: 1) Mix bis-2-hydroxyethyl terephthalate and ethanol; 2) Inducing crystals from the mixture of step 1; and 3) The bis-2-hydroxyethyl terephthalate crystals produced in step 2 are recovered.

Hereinafter, the present invention will be described in detail with respect to each step. ( step 1)

Step 1 of the present disclosure is the step of mixing bis-2-hydroxyethyl terephthalate and ethanol.

Ethanol is the solvent used to purify bis-2-hydroxyethyl terephthalate. Specifically, among the alcohols, methanol reacts with bis-2-hydroxyethyl terephthalate during the purification process, producing by-products. However, it has been demonstrated that the ethanol used in the present disclosure does not react with bis-2-hydroxyethyl terephthalate during the purification process and, unlike the case with methanol, produces no by-products.

Although the bis-2-hydroxyethyl terephthalate to be purified is not particularly limited in this disclosure, bis-2-hydroxyethyl terephthalate obtained by depolymerization of polyester or polyester recovered after consumption is used. 2-hydroxyethyl ester.

In general, when bis-2-hydroxyethyl terephthalate is prepared using recycled PET collected after consumption, the PET is put into EG and depolymerized by boiling at high temperature, but it will change with terephthalic acid. The bis-2-hydroxyethyl esters together produce impurities such as dimers. Additionally, when EG is boiled at high temperature with uncontrolled oxygen, it turns yellow and discoloration chemicals may appear. Additionally, if the recycled PET collected after consumption is colored, excess pigments or dyes may be present. During depolymerization, these dyes and pigments actually dissolve in the EG and, if not properly purified, may mix with the bis-2-hydroxyethyl terephthalate formed.

Therefore, in order to remove substances other than bis-2-hydroxyethyl terephthalate in the purification process as described above, ethanol is used in the present disclosure, and thus the removal effect is significantly greater than that of using water as the solvent The situation is good.

Preferably, in step 1, ethanol is used as the sole solvent. The use of a single solvent means that any solvent other than ethanol that dissolves bis-2-hydroxyethyl terephthalate is not used. In detail, it has been proved that using ethanol as a single solvent is advantageous for removing impurities and improving color, compared to using a mixed solvent of water and alcohol.

When a mixed solvent of water and alcohol is used as the solvent for bis-2-hydroxyethyl terephthalate, the yield from the alcohol solvent may decrease because the solubility in alcohol is different from that in water within a certain temperature range. The solubility is relatively high. In addition, during the solid-liquid separation process, not only impurities but also small amounts of bis-2-hydroxyethyl terephthalate may dissolve together during the washing process. However, it has been confirmed that ethanol is easily separated from bis-2-hydroxyethyl terephthalate crystals in solid-liquid separation compared with water, and impurities and color-inhibiting substances are relatively easily separated from the alcohol solvent.

Preferably, in step 1, bis-2-hydroxyethyl terephthalate is mixed so that the concentration in ethanol is 0.1 to 1 kg/L.

Furthermore, preferably, step 1 is performed at 10 to 70°C. More preferably, step 1 is carried out at 20°C or higher, 30°C or higher or 40°C or higher and 70°C or lower or 65°C or lower.

At the same time, a step of filtering the mixture of step 1 may be added after performing step 1 in order to remove insoluble particles present in the mixture. In the case of the preparation of bis-2-hydroxyethyl terephthalate using recycled PET, the PET is depolymerized. Therefore, if the undepolymerized PET is not removed in the previous step, insoluble particles may be present, and thus can be removed by filtration. ( step 2)

Step 2 of the present disclosure is the step of inducing crystals from the mixture of Step 1 .

For crystallization, it is preferable to cool the mixture of step 1 if necessary, and it is preferable to cool the mixture of step 1 to 10°C to 30°C.

In addition, to induce crystals, seed crystals are preferably added to the mixture of step 1 . Thereby, the size of the crystals of bis-2-hydroxyethyl terephthalate to be produced can be increased, so that the solid-liquid separation can be effectively induced. Preferably, the seed crystals are bis-2-hydroxyethyl terephthalate crystals. These crystals may be bis-2-hydroxyethyl terephthalate crystals obtained by the purification method according to the present disclosure. ( step 3)

Step 3 of the present disclosure is a step of recovering the bis-2-hydroxyethyl terephthalate crystals produced in Step 2.

Recovery is not particularly limited as long as the produced crystals of bis-2-hydroxyethyl terephthalate are separated from the solution, and it is preferably performed by centrifugation.

In addition, optionally, the purification method according to the present disclosure may further include a step of washing or drying the recovered bis-2-hydroxyethyl terephthalate crystals. For washing, preferably ethanol is used, which is the solution previously used for separation. In addition, drying may be performed by a drying process, such as thermal drying, hot air drying, dehumidification drying, vacuum drying, and the like.

Meanwhile, in step 3, ethanol is the main component of the mother liquor remaining after the recovery of bis-2-hydroxyethyl terephthalate crystals. Therefore, after purification of the mother liquor, it can be recovered again in step 1 according to the present disclosure. Since the mother liquor contains impurities and the like, it is preferable to use the mother liquor after purification using activated carbon or zeolite. ( polyester copolymer )

In the present disclosure, a polyester copolymer is provided, wherein the polyester resin is prepared by making bis-2-hydroxyethyl terephthalate, dicarboxylic acid or derivatives thereof purified by the above purification method and containing ethylene glycol It is obtained by copolymerizing an alcohol and a diol of a comonomer, and the polyester copolymer has a structure in which a moiety derived from bis-2-hydroxyethyl terephthalate, a dicarboxylic acid or a derivative thereof The acid moiety of the compound and the diol moiety derived from the diol are repeated. Herein, the polyester copolymer includes 1 to 90 wt% of a moiety derived from bis-2-hydroxyethyl terephthalate. Definition of Terms

Copolymers according to the present disclosure relate to a copolymer prepared by copolymerizing a dicarboxylic acid or a derivative thereof with a diol containing ethylene glycol and a comonomer; and a polyester copolymer prepared by It is prepared by a copolymerization method in which bis-2-hydroxyethyl terephthalate purified by the above purification method participates in the reaction.

As used herein, the term "derived" refers to a moiety or unit derived from a specific compound contained in the product of a chemical reaction when the specific compound participates in the chemical reaction. Specifically, an acid moiety derived from a dicarboxylic acid or a derivative thereof and a diol moiety derived from a diol each refer to a repeating unit formed by an esterification reaction or a polycondensation reaction in a polyester copolymer. In addition, the moiety derived from bis-2-hydroxyethyl terephthalate refers to a repeating unit in the polyester copolymer formed by the esterification reaction in the copolymerization reaction. Dicarboxylic acid or its derivatives

As used in this disclosure, dicarboxylic acids or derivatives thereof refer to the main monomers that together with the diol component constitute the polyester copolymer. In detail, the dicarboxylic acid includes terephthalic acid, and the physical properties, such as heat resistance, chemical resistance, and weather resistance, of the polyester copolymer according to the present disclosure can be improved by the terephthalic acid. In addition, the terephthalic acid residue can also be formed from alkyl terephthalates, preferably dimethyl terephthalic acid.

In addition to terephthalic acid, the dicarboxylic acid component may further include an aromatic dicarboxylic acid component, an aliphatic dicarboxylic acid component, or a mixture thereof. In this case, the dicarboxylic acid components other than terephthalic acid preferably account for 1 to 30 wt % based on the total weight of the total dicarboxylic acid components.

The aromatic dicarboxylic acid component may be an aromatic dicarboxylic acid having 8 to 20 carbon atoms, preferably 8 to 14 carbon atoms, or a mixture thereof. Specific examples of aromatic dicarboxylic acids include isophthalic acid; naphthalenedicarboxylic acid, such as 2,6-naphthalenedicarboxylic acid; diphenyldicarboxylic acid; 4,4'-stilbene dicarboxylic acid; 2,5-furandicarboxylic acid; 2,5-thiophenedicarboxylic acid and its analogs, but not limited thereto. The aliphatic dicarboxylic acid component may be an aliphatic dicarboxylic acid component having 4 to 20 carbon atoms, preferably 4 to 12 carbon atoms, or a mixture thereof. Specific examples of aliphatic dicarboxylic acids include linear, branched, or cyclic aliphatic dicarboxylic acid components, including cyclohexanedicarboxylic acids such as 1,4-cyclohexanedicarboxylic acid and 1,3-cyclohexane dicarboxylic acid), phthalic acid, sebacic acid, succinic acid, isodecylsuccinic acid, maleic acid, fumaric acid, adipic acid, glutaric acid and azelaic acid, but not limited to this. Diol

The diol component used in the present disclosure refers to the main monomer constituting the polyester copolymer together with the above-mentioned dicarboxylic acid or its derivatives. In detail, the diol component contains ethylene glycol and a comonomer, and the comonomer includes cyclohexanedimethanol or isosorbide.

Ethylene glycol is a component that helps improve the transparency and impact strength of polyester copolymers. Preferably, ethylene glycol residues may be included in an amount of 5 to 100 moles based on 100 moles of residues of the total glycol component.

Cyclohexanedimethanol (such as 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol or 1,4-cyclohexanedimethanol) is helpful in improving the properties of the polyester copolymer to be prepared. Components for clarity and impact strength. Preferably, cyclohexanedimethanol residues may be included in an amount of 5 to 90 moles based on 100 moles of residues of the total diol component.

Isosorbide is used to improve the processability of the polyester copolymer to be prepared. Although the diol components of cyclohexanedimethanol and ethylene glycol improve the clarity and impact resistance of the polyester copolymer, to improve processability, the shear thinning characteristics should be improved and the crystallization rate should be reduced. However, it is difficult to achieve these effects using only cyclohexanedimethanol and ethylene glycol. When isosorbide is contained as the diol component, the shear thinning characteristics are improved and the crystallization rate is reduced while maintaining the clarity and impact strength, thereby improving the processability of the polyester copolymer to be prepared. Preferably, the isosorbide may contain isosorbide residues in an amount of 0.1 to 50 moles based on 100 moles of residues of the total glycol component.

Meanwhile, the molar ratio of the comonomer to ethylene glycol (comonomer:ethylene glycol) of the diol component used in the copolymerization of the polyester copolymer according to the present disclosure may preferably be 0.1:1 to 20:1. Herein, "molar ratio" means the molar ratio between components added in the copolymerization of the polyester copolymer. When the molar ratio is less than 0.1, there are problems in that the transparency and impact resistance of the polyester copolymer decrease. When the molar ratio is more than 20, more by-products are produced, which is a factor of quality deterioration of the polyester copolymer. Bis-2 -hydroxyethyl terephthalate

The bis-2-hydroxyethyl terephthalate purified by the above purification method is used as the main monomer constituting the polyester copolymer according to the present disclosure, wherein the polyester copolymer includes 1 to 90 wt % of p-benzene Residue of bis-2-hydroxyethyl dicarboxylate. When the residue of bis-2-hydroxyethyl terephthalate is less than 1 wt%, the content of the above-mentioned diols is relatively high, and thus more by-products derived from diol components, especially from ethylene glycol, are generated. By-products of diols, resulting in deterioration of the quality of polyester copolymers. In addition, when the residue of the recovered bis-2-hydroxyethyl terephthalate is more than 90 wt %, there are problems in that the color quality and transparency of the polyester copolymer are deteriorated. As used herein, "wt%" refers to the ratio based on the total weight of the polyester copolymer. polyester copolymer

Polyester copolymers according to the present disclosure can be prepared by copolymerizing the above-described bis-2-hydroxyethyl terephthalate, dicarboxylic acid or derivatives thereof, and ethylene glycol with comonomers. In this context, the copolymerization can be carried out by esterification reaction (step 1) and polycondensation reaction (step 2) in sequence.

The esterification reaction is carried out in the presence of an esterification reaction catalyst, and an esterification reaction catalyst containing a zinc-based compound may be used. Specific examples of zinc-based catalysts may include zinc acetate, zinc acetate dihydrate, zinc chloride, zinc sulfate, zinc sulfide, zinc carbonate, zinc citrate, zinc gluconate, and mixtures thereof. In addition, the amount of each starting material used is the same as described above.

The esterification reaction can be carried out at a pressure of 0 to 10.0 kg/cm ² and a temperature of 150 to 300°C. The conditions of the esterification reaction can be appropriately adjusted according to the specific characteristics of the polyester to be prepared, the ratio of each component or the process conditions. Specifically, the pressure may be 0 to 5.0 kg/cm ² , more preferably 0.1 to 3.0 kg/cm ² ; and the temperature may be 200 to 270°C, more preferably 240 to 260°C.

The esterification reaction can be carried out in a batch or continuous manner. The respective raw materials can be added individually or in the form of a slurry by mixing a solution of the diol component and the dicarboxylic acid component and the recovered bis-2-hydroxyethyl terephthalate. Alternatively, a diol component such as isosorbide, which is a solid component at room temperature, can be dissolved in water or ethylene glycol and then mixed with a dicarboxylic acid component such as terephthalic acid to form a slurry. Alternatively, after melting the isosorbide at 60°C or higher, a slurry can be prepared by mixing a dicarboxylic acid component, such as terephthalic acid, and other glycol components. Additionally, water can be added to the mixed slurry to help improve slurry fluidity.

The polycondensation reaction may be performed by reacting the esterified product at a temperature of 150 to 300° C. and a pressure of 600 to 0.01 mmHg for 1 to 24 hours.

The polycondensation reaction can be carried out at a temperature of 150 to 300°C, preferably 200 to 290°C, more preferably 260 to 280°C, and a reduced pressure of 600 to 0.01 mmHg, preferably 200 to 0.05 mmHg, more preferably 100 to 0.1 mmHg. The reduced pressure conditions of the polycondensation reaction enable removal of ethylene glycol, which is a by-product of the polycondensation reaction, from the system. Therefore, when the polycondensation reaction does not satisfy the reduced pressure condition of 400 to 0.01 mmHg, the removal of by-products may be insufficient. When the polycondensation reaction is carried out outside the temperature range of 150 to 300°C, that is, when the polycondensation reaction is carried out at a temperature of 150°C or lower, ethyl acetate, which is a by-product of the polycondensation reaction, cannot be effectively removed from the system. Diols, and thus, may reduce the intrinsic viscosity of the final reaction product, which adversely affects the physical properties of the polyester resin to be prepared. When the reaction is carried out at a temperature of 300° C. or higher, there is a high possibility that the appearance of the polyester resin to be prepared may be yellowed. The polycondensation reaction can be carried out for the time required to bring the intrinsic viscosity of the final reaction product to an appropriate level, such as an average residence time of 1 to 24 hours.

In addition, the polycondensation reaction may use a polycondensation catalyst, including titanium-based compounds, germanium-based compounds, antimony-based compounds, aluminum-based compounds, tin-based compounds, or mixtures thereof.

Examples of the titanium-based compound may include tetraethyl titanate, acetyl tripropyl titanate, tetrapropyl titanate, tetrabutyl titanate, 2-ethylhexyl titanate, octanediol titanate, lactic acid Titanate, triethanolamine titanate, acetylacetonate titanate, ethylacetate titanate, isostearyl titanate, titanium dioxide and the like. Examples of germanium-based compounds may include germanium dioxide, germanium tetrachloride, germanium ethylene glycol, germanium acetate, copolymers thereof, and mixtures thereof. Preferably, germanium dioxide can be used, and the germanium dioxide can be in crystalline or amorphous form. Ethylene glycol soluble germanium dioxide may also be used.

Meanwhile, the intrinsic viscosity of the polyester copolymer according to the present disclosure may be 0.50 to 1.0 dl/g, preferably 0.50 to 0.85 dl/g, and more preferably 0.55 to 0.80 dl/g. The method for measuring the intrinsic viscosity will be explained in detail in an example to be described later.

In addition, "(Hunter L value) - (Hunter b value)" (hereinafter referred to as plate color L-b) measured on a 6 mm thick sample of the polyester copolymer according to the present disclosure may be 87 or more, and more preferably 88 or more, 89 or more, or 90 or more. Additionally, the upper limit of the plate color L-b may be 100, and in the present disclosure, the plate color L-b may be 99 or less, 98 or less, 97 or less, 96 or less, or 95 or less. The method for measuring the plate color L-b will be explained in detail in an example to be described later.

In this disclosure, products comprising polyester copolymers are also provided. [ beneficial effect]

As described above, the purification method according to the present disclosure can purify high-purity bis-2-hydroxyethyl terephthalate, and the use of bis-2-hydroxyethyl terephthalate as the polyester copolymer allows good color quality.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

In the following, preferred examples are presented to aid understanding of the present invention. However, the following examples are only provided for easier understanding of the present invention, and the present invention is not limited thereto.

Bis-2-hydroxyethyl terephthalate (BHET) of commercial quality was used, and this bis-2-hydroxyethyl terephthalate was used in the following Preparation Examples, Examples and Comparative Examples. [ Preparation Example] Preparation Example 1 : Purification of bis-2 -hydroxyethyl terephthalate using ethanol

A 2 L jacketed reactor was charged with 500 g of BHET and 1 L of ethanol as solvent and heated to 60°C with stirring. When BHET was completely dissolved, it was maintained at 60°C for 1 hour. At this time, impurities not dissolved in the completely dissolved solution were filtered through a filter to remove impurities, and then the following process was performed.

The solution from which the insoluble substances were removed was cooled to room temperature (25°C), and 1 g of crystals obtained by primary crystallization using ethanol was added to induce crystallization, thereby obtaining BHET crystals. The obtained BHET crystals were separated from the mixed solution mixed with impurities through a filter, washed with ethanol and dried under reduced pressure during the separation process to obtain purified BHET. Preparative Example 2 : BHET purification using recovered solvent

In the same manner as in Preparative Example 1, the new BHET was purified five times each time. At this point, ethanol was recovered from each purification, treated with activated carbon, and then reused for each purification. Specifically, ethanol was recovered and treated with activated carbon in Preparation Example 1, and then used when the process of Preparation Example 1 was performed again. Comparative Preparation Example 1 : BHET purification using distilled water

BHET was purified and obtained in the same manner as in Preparation Example 1, except that distilled water was used instead of ethanol and heated to 75°C instead of 60°C with stirring. Comparative Preparation Example 2 : BHET purification using EG

BHET was purified and obtained in the same manner as in Preparation Example 1 except that ethylene glycol was used instead of ethanol.

The purity of the BHET obtained in the Examples and Comparative Examples was measured by HPLC analysis and is shown in Table 1 below. [Table 1] Example 1 Example 2 Comparative Example 1 Comparative Example 2 solvent Ethanol Ethanol treated with activated carbon distilled water EG BHET purity (%) 98.6 98.5 98.2 96.3 [ Example] Example 1

The bis-2-hydroxyethyl terephthalate (1269.7 g; hereinafter referred to as "r-BHET") prepared in Preparation Example 2, TPA (terephthalic acid; 2361.8 g), EG (ethylene glycol; 673.5 g), CHDM (1,4-cyclohexanedimethanol; 221.5 g) and ISB (isosorbide; 98.2 g) were placed in a 10 L reactor connected to a column and capable of A cooled condenser was performed, and GeO ₂ (1.0 g) as a catalyst, phosphoric acid (1.46 g) as a stabilizer, and cobalt acetate (0.7 g) as a colorant were added thereto.

Next, nitrogen gas was injected into the reactor to form a pressurized state, wherein the pressure of the reactor was 1.0 kgf/cm ² (absolute pressure: 1495.6 mmHg) higher than the normal pressure. Then, the temperature of the reactor was increased to 220°C over 90 minutes, maintained at 220°C for 2 hours, and then increased to 260°C over 2 hours. Subsequently, the esterification reaction was carried out until the mixture in the reactor became transparent under the naked eye, while maintaining the temperature of the reactor at 260°C. During this process, by-products flow through the column and condenser. When the esterification reaction was completed, nitrogen in the pressurized reactor was discharged to the outside to lower the pressure of the reactor to normal pressure, and then the mixture in the reactor was transferred to a 7 L reactor capable of performing vacuum reaction.

Next, the pressure of the reactor was lowered from normal pressure to 5 Torr (absolute pressure: 5 mmHg) over 30 minutes, and the temperature of the reactor was raised to 280° C. over 1 hour to perform a polycondensation reaction, while the The pressure of the reactor was maintained at 1 Torr (absolute pressure: 1 mmHg) or less. In the initial stage of the polycondensation reaction, the stirring rate is set to be high, but as the polycondensation reaction progresses or the temperature of the reactants rises above the set temperature, the viscosity of the reactants will increase, causing the stirring force to weaken. Adjust the stirring rate. The polycondensation reaction was carried out until the intrinsic viscosity (IV) of the mixture (melted) in the reactor became 0.55 dl/g. When the inherent viscosity of the mixture in the reactor reaches the desired level, the mixture is discharged out of the reactor and strands. This material was solidified with a cooling liquid and granulated to have an average weight of about 12 to 14 mg.

The particles were allowed to stand at 150°C for 1 hour to crystallize, and then placed in a 20 L solid phase polymerization reactor. Next, nitrogen gas was flowed into the reactor at a rate of 50 L/min. Here, the temperature of the reactor was increased from room temperature to 140°C at a rate of 40°C/hour and maintained at 140°C for 3 hours. Subsequently, the temperature was further increased to 200°C at a rate of 40°C/hour and maintained at 200°C. The solid-phase polymerization was carried out until the intrinsic viscosity (IV) of the particles in the reactor reached 0.70 dl/g to prepare a polyester copolymer. Example 2

r-BHET (3461.1 g), TPA (969.4 g), EG (12.1 g), CHDM (140.2 g) and ISB (113.7 g) prepared in Preparation Example 1 were placed in a 10 L reactor, which was A column and a condenser capable of cooling by water were connected, and GeO ₂ (1.0 g) as a catalyst, phosphoric acid (1.46 g) as a stabilizer, and cobalt acetate (0.7 g) as a colorant were added thereto.

Next, nitrogen gas was injected into the reactor to form a pressurized state, wherein the pressure of the reactor was 1.0 kgf/cm ² (absolute pressure: 1495.6 mmHg) higher than the normal pressure. Then, the temperature of the reactor was increased to 220°C over 90 minutes, maintained at 220°C for 2 hours, and then increased to 260°C over 2 hours. Subsequently, the esterification reaction was carried out until the mixture in the reactor became transparent under the naked eye, while maintaining the temperature of the reactor at 260°C. During this process, by-products flow through the column and condenser. When the esterification reaction was completed, nitrogen in the pressurized reactor was discharged to the outside to lower the pressure of the reactor to normal pressure, and then the mixture in the reactor was transferred to a 7 L reactor capable of performing vacuum reaction.

Next, the pressure of the reactor was lowered from normal pressure to 5 Torr (absolute pressure: 5 mmHg) over 30 minutes, and the temperature of the reactor was raised to 280° C. over 1 hour to perform a polycondensation reaction, while the The pressure is maintained at 1 Torr (absolute pressure: 1 mmHg) or less. In the initial stage of the polycondensation reaction, the stirring rate is set to be high, but as the polycondensation reaction progresses or the temperature of the reactants rises above the set temperature, the viscosity of the reactants will increase, causing the stirring force to weaken. Adjust the stirring rate. The polycondensation reaction was carried out until the intrinsic viscosity (IV) of the mixture (melted) in the reactor became 0.60 dl/g. When the inherent viscosity of the mixture in the reactor reaches the desired level, the mixture is discharged out of the reactor and divided into strands. This material was solidified with a cooling liquid and granulated to have an average weight of about 12 to 14 mg.

The particles were allowed to stand at 150°C for 1 hour to crystallize, and then placed in a 20 L solid phase polymerization reactor. Next, nitrogen gas was flowed into the reactor at a rate of 50 L/min. Here, the temperature of the reactor was increased from room temperature to 140°C at a rate of 40°C/hour and maintained at 140°C for 3 hours. Subsequently, the temperature was further increased to 200°C at a rate of 40°C/hour and maintained at 200°C. The solid-phase polymerization was carried out until the intrinsic viscosity (IV) of the particles in the reactor reached 0.95 dl/g to prepare a polyester copolymer. Example 3

r-BHET (4715.8 g), TPA (420.3 g) and CHDM (121.5 g) prepared in Preparation Example 1 were placed in a 10 L reactor connected with a column and capable of cooling by water. A condenser, and TiO ₂ /SiO ₂ copolymer (0.5 g) as a catalyst, phosphoric acid (1.46 g) as a stabilizer, Polysynthren Blue RLS (manufactured by Clarient, 0.016 g) as a blue toner, and Solvaperm Red BB (manufactured by Clarient, 0.004 g) as a red toner.

Next, nitrogen gas was injected into the reactor to form a pressurized state, wherein the pressure of the reactor was 0.5 kgf/cm ² (absolute pressure: 1127.8 mmHg) higher than the normal pressure. Then, the temperature of the reactor was increased to 220°C over 90 minutes, maintained at 220°C for 2 hours, and then increased to 260°C over 2 hours. Subsequently, the esterification reaction was carried out until the mixture in the reactor became transparent under the naked eye, while maintaining the temperature of the reactor at 260°C. During this process, by-products flow through the column and condenser. When the esterification reaction was completed, nitrogen in the pressurized reactor was discharged to the outside to lower the pressure of the reactor to normal pressure, and then the mixture in the reactor was transferred to a 7 L reactor capable of performing vacuum reaction.

Next, the pressure of the reactor was lowered from normal pressure to 5 Torr (absolute pressure: 5 mmHg) over 30 minutes, and the temperature of the reactor was raised to 275° C. over 1 hour to carry out the polycondensation reaction, while the The pressure is maintained at 1 Torr (absolute pressure: 1 mmHg) or less. In the initial stage of the polycondensation reaction, the stirring rate is set to be high, but as the polycondensation reaction progresses or the temperature of the reactants rises above the set temperature, the viscosity of the reactants will increase, causing the stirring force to weaken. Adjust the stirring rate. The polycondensation reaction was carried out until the intrinsic viscosity (IV) of the mixture (melted) in the reactor became 0.60 dl/g. When the inherent viscosity of the mixture in the reactor reaches the desired level, the mixture is discharged out of the reactor and divided into strands. This material was solidified with a cooling liquid and granulated to have an average weight of about 12 to 14 mg.

The particles were allowed to stand at 150°C for 1 hour to crystallize, and then placed in a 20 L solid phase polymerization reactor. Next, nitrogen gas was flowed into the reactor at a rate of 50 L/min. Here, the temperature of the reactor was increased from room temperature to 140°C at a rate of 40°C/hour and maintained at 140°C for 3 hours. Subsequently, the temperature was further increased to 210°C at a rate of 40°C/hour and maintained at 210°C. The solid-phase polymerization was carried out until the intrinsic viscosity (IV) of the particles in the reactor reached 0.80 dl/g to prepare a polyester copolymer. Example 4

r-BHET (795.8 g), TPA (3814.0 g), EG (1554.0 g) and CHDM (188.0 g) prepared in Preparation Example 2 were placed in a 10 L reactor connected with a column and capable of A condenser cooled by water, and thereto were added TiO ₂ /SiO ₂ copolymer (0.5 g) as a catalyst, phosphoric acid (1.46 g) as a stabilizer, and cobalt acetate (1.1 g) as a colorant.

Next, nitrogen gas was injected into the reactor to form a pressurized state, wherein the pressure of the reactor was 1.0 kgf/cm ² (absolute pressure: 1495.6 mmHg) higher than the normal pressure. Then, the temperature of the reactor was increased to 220°C over 90 minutes, maintained at 220°C for 2 hours, and then increased to 250°C over 2 hours. Subsequently, the esterification reaction was carried out until the mixture in the reactor became transparent under the naked eye, while maintaining the temperature of the reactor at 250°C. During this process, by-products flow through the column and condenser. When the esterification reaction was completed, nitrogen in the pressurized reactor was discharged to the outside to lower the pressure of the reactor to normal pressure, and then the mixture in the reactor was transferred to a 7 L reactor capable of performing vacuum reaction.

Next, the pressure of the reactor was lowered from normal pressure to 5 Torr (absolute pressure: 5 mmHg) over 30 minutes, and the temperature of the reactor was raised to 265° C. over 1 hour to carry out the polycondensation reaction, while the The pressure is maintained at 1 Torr (absolute pressure: 1 mmHg) or less. In the initial stage of the polycondensation reaction, the stirring rate is set to be high, but as the polycondensation reaction progresses or the temperature of the reactants rises above the set temperature, the viscosity of the reactants will increase, causing the stirring force to weaken. Adjust the stirring rate. The polycondensation reaction was carried out until the intrinsic viscosity (IV) of the mixture (melted) in the reactor became 0.55 dl/g. When the inherent viscosity of the mixture in the reactor reaches the desired level, the mixture is discharged out of the reactor and divided into strands. This material was solidified with a cooling liquid and granulated to have an average weight of about 12 to 14 mg.

The particles were allowed to stand at 150°C for 1 hour to crystallize, and then placed in a 20 L solid phase polymerization reactor. Next, nitrogen gas was flowed into the reactor at a rate of 50 L/min. Here, the temperature of the reactor was increased from room temperature to 140°C at a rate of 40°C/hour and maintained at 140°C for 3 hours. Subsequently, the temperature was further increased to 220°C at a rate of 40°C/hour and maintained at 220°C. The solid phase polymerization was carried out until the intrinsic viscosity (IV) of the particles in the reactor reached 0.85 dl/g to prepare a polyester copolymer. Example 5

r-BHET (2439.2 g), TPA (1471.5 g), EG (68.7 g) and CHDM (797.8 g) prepared in Preparation Example 1 were placed in a 10 L reactor connected with a column and capable of A condenser cooled by water, and thereto were added TiO ₂ /SiO ₂ copolymer (1.0 g) as a catalyst, phosphoric acid (1.46 g) as a stabilizer, and cobalt acetate (0.8 g) as a colorant.

Next, nitrogen gas was injected into the reactor to form a pressurized state, wherein the pressure of the reactor was higher than normal pressure by 2.0 kgf/cm ² (absolute pressure: 2231.1 mmHg). Then, the temperature of the reactor was increased to 220°C over 90 minutes, maintained at 220°C for 2 hours, and then increased to 255°C over 2 hours. Subsequently, the esterification reaction was carried out until the mixture in the reactor became transparent under the naked eye, while maintaining the temperature of the reactor at 255°C. During this process, by-products flow through the column and condenser. When the esterification reaction was completed, nitrogen in the pressurized reactor was discharged to the outside to lower the pressure of the reactor to normal pressure, and then the mixture in the reactor was transferred to a 7 L reactor capable of performing vacuum reaction.

Next, the pressure of the reactor was lowered from normal pressure to 5 Torr (absolute pressure: 5 mmHg) over 30 minutes, and the temperature of the reactor was raised to 285° C. over 1 hour to carry out the polycondensation reaction, while the The pressure is maintained at 1 Torr (absolute pressure: 1 mmHg) or less. In the initial stage of the polycondensation reaction, the stirring rate is set to be high, but as the polycondensation reaction progresses or the temperature of the reactants rises above the set temperature, the viscosity of the reactants will increase, causing the stirring force to weaken. Adjust the stirring rate. The polycondensation reaction was carried out until the intrinsic viscosity (IV) of the mixture (melted) in the reactor became 0.70 dl/g. When the inherent viscosity of the mixture in the reactor reaches the desired level, the mixture is discharged out of the reactor and divided into strands. This material was solidified with a cooling liquid and pelletized to have an average weight of about 12 to 14 mg to prepare a polyester copolymer. Example 6

r-BHET (1852.6 g), TPA (1816.1 g), EG (339.2 g) and CHDM (525.1 g) prepared in Preparation Example 2 were placed in a 10 L reactor connected with a column and capable of A condenser cooled by water, and GeO ₂ (1.0 g) as a catalyst, phosphoric acid (1.46 g) as a stabilizer, and cobalt acetate (1.0 g) as a colorant were added thereto.

Next, nitrogen gas was injected into the reactor to form a pressurized state, wherein the pressure of the reactor was 1.5 kgf/cm ² (absolute pressure: 1715.5 mmHg) higher than the normal pressure. Then, the temperature of the reactor was increased to 220°C over 90 minutes, maintained at 220°C for 2 hours, and then increased to 250°C over 2 hours. Subsequently, the esterification reaction was carried out until the mixture in the reactor became transparent under the naked eye, while maintaining the temperature of the reactor at 250°C. During this process, by-products flow through the column and condenser. When the esterification reaction was completed, nitrogen in the pressurized reactor was discharged to the outside to lower the pressure of the reactor to normal pressure, and then the mixture in the reactor was transferred to a 7 L reactor capable of performing vacuum reaction.

Next, the pressure of the reactor was lowered from normal pressure to 5 Torr (absolute pressure: 5 mmHg) over 30 minutes, and the temperature of the reactor was raised to 270° C. over 1 hour to carry out the polycondensation reaction, while the The pressure is maintained at 1 Torr (absolute pressure: 1 mmHg) or less. In the initial stage of the polycondensation reaction, the stirring rate is set to be high, but as the polycondensation reaction progresses or the temperature of the reactants rises above the set temperature, the viscosity of the reactants will increase, causing the stirring force to weaken. Adjust the stirring rate. The polycondensation reaction was carried out until the intrinsic viscosity (IV) of the mixture (melted) in the reactor became 0.80 dl/g. When the inherent viscosity of the mixture in the reactor reaches the desired level, the mixture is discharged out of the reactor and divided into strands. This material was solidified with a cooling liquid and pelletized to have an average weight of about 12 to 14 mg to prepare a polyester copolymer. Example 7

r-BHET (1132.4 g), TPA (2220.2 g), EG (265.4 g), CHDM (1284.0 g) and ISB (156.2 g) prepared in Preparation Example 1 were placed in a 10 L reactor, which was A column and a condenser capable of being cooled by water were connected, and GeO ₂ (1.0 g) as a catalyst, phosphoric acid (1.46 g) as a stabilizer, Polysynthren Blue RLS as a blue toner (by manufactured by Clarient, 0.013 g) and Solvaperm Red BB (manufactured by Clarient, 0.004 g) as a red toner.

Next, nitrogen gas was injected into the reactor to form a pressurized state, wherein the pressure of the reactor was 1.0 kgf/cm ² (absolute pressure: 1495.6 mmHg) higher than the normal pressure. Then, the temperature of the reactor was increased to 220°C over 90 minutes, maintained at 220°C for 2 hours, and then increased to 265°C over 2 hours. Subsequently, the esterification reaction was carried out until the mixture in the reactor became transparent under the naked eye, while maintaining the temperature of the reactor at 265°C. During this process, by-products flow through the column and condenser. When the esterification reaction was completed, nitrogen in the pressurized reactor was discharged to the outside to lower the pressure of the reactor to normal pressure, and then the mixture in the reactor was transferred to a 7 L reactor capable of performing vacuum reaction.

Next, the pressure of the reactor was lowered from normal pressure to 5 Torr (absolute pressure: 5 mmHg) over 30 minutes, and the temperature of the reactor was raised to 275° C. over 1 hour to carry out the polycondensation reaction, while the The pressure is maintained at 1 Torr (absolute pressure: 1 mmHg) or less. In the initial stage of the polycondensation reaction, the stirring rate is set to be high, but as the polycondensation reaction progresses or the temperature of the reactants rises above the set temperature, the viscosity of the reactants will increase, causing the stirring force to weaken. Adjust the stirring rate. The polycondensation reaction was carried out until the intrinsic viscosity (IV) of the mixture (melted) in the reactor became 0.65 dl/g. When the inherent viscosity of the mixture in the reactor reaches the desired level, the mixture is discharged out of the reactor and divided into strands. This material was solidified with a cooling liquid and pelletized to have an average weight of about 12 to 14 mg to prepare a polyester copolymer. Example 8

r-BHET (40.9 g), TPA (2643.1 g), EG (329.1 g), CHDM (1158.0 g) and ISB (587.0 g) prepared in Preparation Example 2 were placed in a 10 L reactor, which was A column and a condenser capable of being cooled by water were connected, and GeO ₂ (1.0 g) as a catalyst, phosphoric acid (1.46 g) as a stabilizer, Polysynthren Blue RLS as a blue toner (by manufactured by Clarient, 0.020 g) and Solvaperm Red BB (manufactured by Clarient, 0.008 g) as a red toner.

Next, nitrogen gas was injected into the reactor to form a pressurized state, wherein the pressure of the reactor was 0.5 kgf/cm ² (absolute pressure: 1127.8 mmHg) higher than the normal pressure. Then, the temperature of the reactor was increased to 220°C over 90 minutes, maintained at 220°C for 2 hours, and then increased to 260°C over 2 hours. Subsequently, the esterification reaction was carried out until the mixture in the reactor became transparent under the naked eye, while maintaining the temperature of the reactor at 260°C. During this process, by-products flow through the column and condenser. When the esterification reaction was completed, nitrogen in the pressurized reactor was discharged to the outside to lower the pressure of the reactor to normal pressure, and then the mixture in the reactor was transferred to a 7 L reactor capable of performing vacuum reaction.

Next, the pressure of the reactor was lowered from normal pressure to 5 Torr (absolute pressure: 5 mmHg) over 30 minutes, and the temperature of the reactor was raised to 275° C. over 1 hour to carry out the polycondensation reaction, while the The pressure is maintained at 1 Torr (absolute pressure: 1 mmHg) or less. In the initial stage of the polycondensation reaction, the stirring rate is set to be high, but as the polycondensation reaction progresses or the temperature of the reactants rises above the set temperature, the viscosity of the reactants will increase, causing the stirring force to weaken. Adjust the stirring rate. The polycondensation reaction was carried out until the intrinsic viscosity (IV) of the mixture (melted) in the reactor became 0.80 dl/g. When the inherent viscosity of the mixture in the reactor reaches the desired level, the mixture is discharged out of the reactor and divided into strands. This material was solidified with a cooling liquid and pelletized to have an average weight of about 12 to 14 mg to prepare a polyester copolymer. Example 9

r-BHET (3418.5 g), TPA (957.5 g), DMT (dimethyl terephthalate; 1119.0 g), EG (345.7 g), CHDM (221.5 g) and ISB (84.2 g) prepared in Preparation Example 1 were mixed with g) was placed in a 10 L reactor connected with a column and a condenser capable of cooling by water, and to which were added manganese (II) acetate tetrahydrate (1.5 _g ) and Sb as catalysts _O3 (1.8 g) and cobalt acetate (0.7 g) as colorant.

Next, nitrogen gas was injected into the reactor to bring the pressure of the reactor to normal pressure. Then, the temperature of the reactor was increased to 220°C over 90 minutes, maintained at 220°C for 2 hours, and then increased to 240°C over 2 hours. Subsequently, the esterification reaction was carried out until the mixture in the reactor became transparent under the naked eye, while maintaining the temperature of the reactor at 240°C. During this process, by-products flow through the column and condenser. When the esterification reaction was completed, nitrogen in the pressurized reactor was discharged to the outside to lower the pressure of the reactor to normal pressure, and then the mixture in the reactor was transferred to a 7 L reactor capable of performing vacuum reaction.

Next, the pressure of the reactor was lowered from normal pressure to 5 Torr (absolute pressure: 5 mmHg) over 30 minutes, and the temperature of the reactor was raised to 265° C. over 1 hour to carry out the polycondensation reaction, while the The pressure is maintained at 1 Torr (absolute pressure: 1 mmHg) or less. In the initial stage of the polycondensation reaction, the stirring rate is set to be high, but as the polycondensation reaction progresses or the temperature of the reactants rises above the set temperature, the viscosity of the reactants will increase, causing the stirring force to weaken. Adjust the stirring rate. The polycondensation reaction was carried out until the intrinsic viscosity (IV) of the mixture (melted) in the reactor became 0.60 dl/g. When the inherent viscosity of the mixture in the reactor reaches the desired level, the mixture is discharged out of the reactor and divided into strands. This material was solidified with a cooling liquid and granulated to have an average weight of about 12 to 14 mg.

The particles were allowed to stand at 150°C for 1 hour to crystallize, and then placed in a 20 L solid phase polymerization reactor. Next, nitrogen gas was flowed into the reactor at a rate of 50 L/min. Here, the temperature of the reactor was increased from room temperature to 140°C at a rate of 40°C/hour and maintained at 140°C for 3 hours. Subsequently, the temperature was further increased to 200°C at a rate of 40°C/hour and maintained at 200°C. The solid-phase polymerization was carried out until the intrinsic viscosity (IV) of the particles in the reactor reached 0.95 dl/g to prepare a polyester copolymer. Example 10

r-BHET (3461.1 g), TPA (969.4 g), IPA (isophthalic acid; 2262.0 g), EG (12.1 g), CHDM (140.2 g) and ISB (113.7 g) prepared in Preparation Example 2 were placed It was placed in a 10 L reactor connected with a column and a condenser capable of cooling by water, and GeO ₂ (1.0 g) as a catalyst and cobalt acetate (0.7 g) as a colorant were added thereto. .

Next, nitrogen gas was injected into the reactor to form a pressurized state, wherein the pressure of the reactor was 3.0 kgf/cm ² (absolute pressure: 2956.7 mmHg) higher than the normal pressure. Then, the temperature of the reactor was increased to 220°C over 90 minutes, maintained at 220°C for 2 hours, and then increased to 260°C over 2 hours. Subsequently, the esterification reaction was carried out until the mixture in the reactor became transparent under the naked eye, while maintaining the temperature of the reactor at 260°C. During this process, by-products flow through the column and condenser. When the esterification reaction was completed, nitrogen in the pressurized reactor was discharged to the outside to lower the pressure of the reactor to normal pressure, and then the mixture in the reactor was transferred to a 7 L reactor capable of performing vacuum reaction.

Next, the pressure of the reactor was lowered from normal pressure to 5 Torr (absolute pressure: 5 mmHg) over 30 minutes, and the temperature of the reactor was raised to 280° C. over 1 hour to perform a polycondensation reaction, while the The pressure is maintained at 1 Torr (absolute pressure: 1 mmHg) or less. In the initial stage of the polycondensation reaction, the stirring rate is set to be high, but as the polycondensation reaction progresses or the temperature of the reactants rises above the set temperature, the viscosity of the reactants will increase, causing the stirring force to weaken. Adjust the stirring rate. The polycondensation reaction was carried out until the intrinsic viscosity (IV) of the mixture (melted) in the reactor became 0.60 dl/g. When the inherent viscosity of the mixture in the reactor reaches the desired level, the mixture is discharged out of the reactor and divided into strands. This material was solidified with a cooling liquid and granulated to have an average weight of about 12 to 14 mg.

The particles were allowed to stand at 150°C for 1 hour to crystallize, and then placed in a 20 L solid phase polymerization reactor. Next, nitrogen gas was flowed into the reactor at a rate of 50 L/min. Here, the temperature of the reactor was increased from room temperature to 140°C at a rate of 40°C/hour and maintained at 140°C for 3 hours. Subsequently, the temperature was further increased to 190°C at a rate of 40°C/hour and maintained at 190°C. The solid-phase polymerization was carried out until the intrinsic viscosity (IV) of the particles in the reactor reached 1.0 dl/g to prepare a polyester copolymer. Comparative Example 1

Unpurified r-BHET (1269.7 g), TPA (2361.8 g), EG (673.5 g), CHDM (221.5 g) and ISB (98.2 g) were placed in a 10 L reactor connected with The column and condenser, which can be cooled by water, were added _GeO2 as catalyst (1.0 g) and phosphoric acid (1.46 g) as stabilizer.

Next, nitrogen gas was injected into the reactor to form a pressurized state, wherein the pressure of the reactor was 0.5 kgf/cm ² (absolute pressure: 1127.8 mmHg) higher than the normal pressure. Then, the temperature of the reactor was increased to 220°C over 90 minutes, maintained at 220°C for 2 hours, and then increased to 260°C over 2 hours. Subsequently, the esterification reaction was carried out until the mixture in the reactor became transparent under the naked eye, while maintaining the temperature of the reactor at 260°C. During this process, by-products flow through the column and condenser. When the esterification reaction was completed, nitrogen in the pressurized reactor was discharged to the outside to lower the pressure of the reactor to normal pressure, and then the mixture in the reactor was transferred to a 7 L reactor capable of performing vacuum reaction.

Next, the pressure of the reactor was lowered from normal pressure to 5 Torr (absolute pressure: 5 mmHg) over 30 minutes, and the temperature of the reactor was raised to 280° C. over 1 hour to perform a polycondensation reaction, while the The pressure is maintained at 1 Torr (absolute pressure: 1 mmHg) or less. In the initial stage of the polycondensation reaction, the stirring rate is set to be high, but as the polycondensation reaction progresses or the temperature of the reactants rises above the set temperature, the viscosity of the reactants will increase, causing the stirring force to weaken. Adjust the stirring rate. The polycondensation reaction was carried out until the intrinsic viscosity (IV) of the mixture (melted) in the reactor became 0.60 dl/g. When the inherent viscosity of the mixture in the reactor reaches the desired level, the mixture is discharged out of the reactor and divided into strands. This material was solidified with a cooling liquid and granulated to have an average weight of about 12 to 14 mg.

The particles were allowed to stand at 150°C for 1 hour to crystallize, and then placed in a 20 L solid phase polymerization reactor. Next, nitrogen gas was flowed into the reactor at a rate of 50 L/min. Here, the temperature of the reactor was increased from room temperature to 140°C at a rate of 40°C/hour and maintained at 140°C for 3 hours. Subsequently, the temperature was further increased to 200°C at a rate of 40°C/hour and maintained at 200°C. The solid-phase polymerization was carried out until the intrinsic viscosity (IV) of the particles in the reactor reached 0.70 dl/g to prepare a polyester copolymer. Comparative Example 2

Unpurified r-BHET (304.1 g), TPA (2640.8 g), EG (583.3 g), CHDM (1231.6 g) and ISB (25.0 g) were placed in a 10 L reactor connected with A column and a condenser capable of being cooled by water, to which were added Ge ₂ O (1.0 g) as a catalyst, phosphoric acid (1.46 g) as a stabilizer, Polysynthren Blue RLS (by Clarient) as a blue toner. manufactured, 0.012 g) and Solvaperm Red BB (manufactured by Clarient, 0.004 g) as a red toner.

Next, nitrogen gas was injected into the reactor to form a pressurized state, wherein the pressure of the reactor was 0.5 kgf/cm ² (absolute pressure: 1127.8 mmHg) higher than the normal pressure. Then, the temperature of the reactor was increased to 220°C over 90 minutes, maintained at 220°C for 2 hours, and then increased to 255°C over 2 hours. Subsequently, the esterification reaction was carried out until the mixture in the reactor became transparent under the naked eye, while maintaining the temperature of the reactor at 255°C. During this process, by-products flow through the column and condenser. When the esterification reaction was completed, nitrogen in the pressurized reactor was discharged to the outside to lower the pressure of the reactor to normal pressure, and then the mixture in the reactor was transferred to a 7 L reactor capable of performing vacuum reaction.

Next, the pressure of the reactor was lowered from normal pressure to 5 Torr (absolute pressure: 5 mmHg) over 30 minutes, and the temperature of the reactor was raised to 280° C. over 1 hour to perform a polycondensation reaction, while the The pressure is maintained at 1 Torr (absolute pressure: 1 mmHg) or less. In the initial stage of the polycondensation reaction, the stirring rate is set to be high, but as the polycondensation reaction progresses or the temperature of the reactants rises above the set temperature, the viscosity of the reactants will increase, causing the stirring force to weaken. Adjust the stirring rate. The polycondensation reaction was carried out until the intrinsic viscosity (IV) of the mixture (melted) in the reactor became 0.75 dl/g. When the inherent viscosity of the mixture in the reactor reaches the desired level, the mixture is discharged out of the reactor and divided into strands. This material was solidified with a cooling liquid and pelletized to have an average weight of about 12 to 14 mg to prepare a polyester copolymer. Comparative Example 3

r-BHET (3898.7 g), TPA (162.6 g), EG (81.0 g) and ISB (95.4 g) prepared in Preparation Example 1 were placed in a 10 L reactor connected with a column and capable of A condenser cooled by water, and thereto were added Ge ₂ O (1.0 g) as a catalyst, phosphoric acid (1.46 g) as a stabilizer, Polysynthren Blue RLS (manufactured by Clarient, 0.010 g) as a blue toner ) and Solvaperm Red BB (manufactured by Clarient, 0.003 g) as a red toner.

Next, nitrogen gas was injected into the reactor to form a pressurized state, wherein the pressure of the reactor was 0.1 kgf/cm ² (absolute pressure: 823.6 mmHg) higher than the normal pressure. Then, the temperature of the reactor was increased to 220°C over 90 minutes, maintained at 220°C for 2 hours, and then increased to 260°C over 2 hours. Subsequently, the esterification reaction was carried out until the mixture in the reactor became transparent under the naked eye, while maintaining the temperature of the reactor at 260°C. During this process, by-products flow through the column and condenser. When the esterification reaction was completed, nitrogen in the pressurized reactor was discharged to the outside to lower the pressure of the reactor to normal pressure, and then the mixture in the reactor was transferred to a 7 L reactor capable of performing vacuum reaction.

Next, the pressure of the reactor was lowered from normal pressure to 5 Torr (absolute pressure: 5 mmHg) over 30 minutes, and the temperature of the reactor was raised to 270° C. over 1 hour to carry out the polycondensation reaction, while the The pressure is maintained at 1 Torr (absolute pressure: 1 mmHg) or less. In the initial stage of the polycondensation reaction, the stirring rate is set to be high, but as the polycondensation reaction progresses or the temperature of the reactants rises above the set temperature, the viscosity of the reactants will increase, causing the stirring force to weaken. Adjust the stirring rate. The polycondensation reaction was carried out until the intrinsic viscosity (IV) of the mixture (melted) in the reactor became 0.65 dl/g. When the inherent viscosity of the mixture in the reactor reaches the desired level, the mixture is discharged out of the reactor and divided into strands. This material was solidified with a cooling liquid and granulated to have an average weight of about 12 to 14 mg.

The particles were allowed to stand at 150°C for 1 hour to crystallize, and then placed in a 20 L solid phase polymerization reactor. Next, nitrogen gas was flowed into the reactor at a rate of 50 L/min. Here, the temperature of the reactor was increased from room temperature to 140°C at a rate of 40°C/hour and maintained at 140°C for 3 hours. Subsequently, the temperature was further increased to 220°C at a rate of 40°C/hour and maintained at 220°C. The solid phase polymerization was carried out until the intrinsic viscosity (IV) of the particles in the reactor reached 0.85 dl/g to prepare a polyester copolymer. Comparative Example 4

The r-BHET solution (735.6 g), TPA (2724.3 g), EG (1239.0 g), CHDM (222.4 g) and ISB (98.7 g) prepared in Comparative Preparation Example 1 were placed in a 10 L reactor, the The reactor was connected with a column and a condenser capable of cooling by water, and Ge ₂ O (1.0 g) as a catalyst and phosphoric acid (1.46 g) as a stabilizer were added thereto.

Next, nitrogen gas was injected into the reactor to form a pressurized state, wherein the pressure of the reactor was 0.5 kgf/cm ² (absolute pressure: 1127.8 mmHg) higher than the normal pressure. Then, the temperature of the reactor was increased to 220°C over 90 minutes, maintained at 220°C for 2 hours, and then increased to 260°C over 2 hours. Subsequently, the esterification reaction was carried out until the mixture in the reactor became transparent under the naked eye, while maintaining the temperature of the reactor at 260°C. During this process, by-products flow through the column and condenser. When the esterification reaction was completed, nitrogen in the pressurized reactor was discharged to the outside to lower the pressure of the reactor to normal pressure, and then the mixture in the reactor was transferred to a 7 L reactor capable of performing vacuum reaction.

Next, the pressure of the reactor was lowered from normal pressure to 5 Torr (absolute pressure: 5 mmHg) over 30 minutes, and the temperature of the reactor was raised to 280° C. over 1 hour to perform a polycondensation reaction, while the The pressure is maintained at 1 Torr (absolute pressure: 1 mmHg) or less. In the initial stage of the polycondensation reaction, the stirring rate is set to be high, but as the polycondensation reaction progresses or the temperature of the reactants rises above the set temperature, the viscosity of the reactants will increase, causing the stirring force to weaken. Adjust the stirring rate. The polycondensation reaction was carried out until the intrinsic viscosity (IV) of the mixture (melted) in the reactor became 0.60 dl/g. When the inherent viscosity of the mixture in the reactor reaches the desired level, the mixture is discharged out of the reactor and divided into strands. This material was solidified with a cooling liquid and granulated to have an average weight of about 12 to 14 mg.

The particles were allowed to stand at 150°C for 1 hour to crystallize, and then placed in a 20 L solid phase polymerization reactor. Next, nitrogen gas was flowed into the reactor at a rate of 50 L/min. Here, the temperature of the reactor was increased from room temperature to 140°C at a rate of 40°C/hour and maintained at 140°C for 3 hours. Subsequently, the temperature was further increased to 200°C at a rate of 40°C/hour and maintained at 200°C. The solid-phase polymerization was carried out until the intrinsic viscosity (IV) of the particles in the reactor reached 0.70 dl/g to prepare a polyester copolymer. Comparative Example 5

r-BHET (2613.6 g), TPA (1708.1 g), EG (1103.7 g), CHDM (296.3 g) and ISB (105.2 g) prepared in Comparative Preparation Example 2 were placed in a 10 L reactor, and the reaction A pipe column and a condenser capable of cooling by water were connected to the device, and GeO ₂ (1.0 g) as a catalyst, phosphoric acid (1.46 g) as a stabilizer, and cobalt acetate (0.7 g) as a colorant were added thereto. .

Next, nitrogen gas was injected into the reactor to form a pressurized state, wherein the pressure of the reactor was 1.0 kgf/cm ² (absolute pressure: 1495.6 mmHg) higher than the normal pressure. Then, the temperature of the reactor was increased to 220°C over 90 minutes, maintained at 220°C for 2 hours, and then increased to 260°C over 2 hours. Subsequently, the esterification reaction was carried out until the mixture in the reactor became transparent under the naked eye, while maintaining the temperature of the reactor at 260°C. During this process, by-products flow through the column and condenser. When the esterification reaction was completed, nitrogen in the pressurized reactor was discharged to the outside to lower the pressure of the reactor to normal pressure, and then the mixture in the reactor was transferred to a 7 L reactor capable of performing vacuum reaction.

Next, the pressure of the reactor was lowered from normal pressure to 5 Torr (absolute pressure: 5 mmHg) over 30 minutes, and the temperature of the reactor was raised to 280° C. over 1 hour to perform a polycondensation reaction, while the The pressure is maintained at 1 Torr (absolute pressure: 1 mmHg) or less. In the initial stage of the polycondensation reaction, the stirring rate is set to be high, but as the polycondensation reaction progresses or the temperature of the reactants rises above the set temperature, the viscosity of the reactants will increase, causing the stirring force to weaken. Adjust the stirring rate. The polycondensation reaction was carried out until the intrinsic viscosity (IV) of the mixture (melted) in the reactor became 0.60 dl/g. When the inherent viscosity of the mixture in the reactor reaches the desired level, the mixture is discharged out of the reactor and divided into strands. This material was solidified with a cooling liquid and granulated to have an average weight of about 12 to 14 mg.

The particles were allowed to stand at 150°C for 1 hour to crystallize, and then placed in a 20 L solid phase polymerization reactor. Next, nitrogen gas was flowed into the reactor at a rate of 50 L/min. Here, the temperature of the reactor was increased from room temperature to 140°C at a rate of 40°C/hour and maintained at 140°C for 3 hours. Subsequently, the temperature was further increased to 200°C at a rate of 40°C/hour and maintained at 200°C. The solid-phase polymerization was carried out until the intrinsic viscosity (IV) of the particles in the reactor reached 0.95 dl/g to prepare a polyester copolymer. [ Experimental example ]

The physical properties of the polyester copolymers prepared in the Examples and Comparative Examples were evaluated as follows. 1) Residue composition

The composition (mol%) of residues derived from acids and diols in the polyester resin was confirmed by 1H-NMR spectroscopy using NMR at 25°C after dissolving the sample in _CDCl solvent at a concentration of 3 mg/mL Resonance equipment (JEOL, 600 MHz FT-NMR) was obtained. In addition, the residue of TMA was confirmed by quantitative analysis of the spectrum in which benzene-1 produced by the reaction of ethanol and TMA via ethanol decomposition was measured using gas chromatography (Agilent Technologies, 7890B) at 250°C, 2,4-triethylformate content. And, it was confirmed by the content (wt %) based on the total weight of the polyester resin. 2) Inherent viscosity

[式2]

(3)板色彩L-b After dissolving the polyester copolymer in ortho-chlorophenol (OCP) at a concentration of 0.12% at 150°C, the intrinsic viscosity was measured at 35°C in a constant temperature bath using an Ubbelohde viscometer. Specifically, the temperature of the viscometer was maintained at 35°C, and the time it took for the solvent to pass through certain internal sections of the viscometer (efflux time; t ₀ ) and the time it took for the solution to pass through the viscometer ( t). Subsequently, the specific viscosity is calculated by substituting t ₀ and t into Equation 1, and the intrinsic viscosity is calculated by substituting the calculated specific viscosity into Equation 2. [Formula 1]

[Formula 2]

(3) Board color Lb

Color and brightness of the samples were measured using a Varian Cary 5 UV/Vis/NIR spectrophotometer equipped with a diffuse reflectance accessory. Polyester resin specimens with a thickness of 6 mm were prepared and transmission data were obtained by an Illuminant D65 at an observer angle of 2°. This was processed in Grams/32 software using a color analysis device to calculate the Hunter L*a*b* value, and the result (L-b) obtained by subtracting the b value from the L value (L-b) is described in the table below.

The results are shown in Table 2 below. [Table 2] r-BHET CHDM ISB IV 6T Color Lb unit wt% mol% mol% dg/l - Example 1 30 8 2 0.70 93 Example 2 75 5 2 0.95 90 Example 3 89 4 0 0.80 87 Example 4 14 5 0 0.85 91 Example 5 50 30 0 0.70 90 Example 6 42 20 0 0.80 92 Example 7 twenty two 50 3 0.65 90 Example 8 1 50 15 0.80 88 Example 9 69 8 2 0.95 87 Example 10 75 5 2 1.00 88 Comparative Example 1 30 8 2 0.70 85 Comparative Example 2 7 50 1 0.75 82 Comparative Example 3 92 0 4 0.85 86 Comparative Example 4 16 8 1 0.70 82 Comparative Example 5 47 10 0 0.95 84

As shown in Table 2, polyester copolymers prepared using bis-2-hydroxyethyl terephthalate purified according to the present disclosure (Examples 1-8) had excellent color L-b values of 87 or greater. On the other hand, polyester copolymers prepared using unpurified or purified bis-2-hydroxyethyl terephthalate according to Comparative Preparation Examples 1 and 2 (Comparative Examples 1 to 5) had a color L-b lower than the above-mentioned value value.

Therefore, it was confirmed that the polyester has excellent color quality when the bis-2-hydroxyethyl terephthalate purified by the purification method according to the present disclosure is used as the monomer of the polyester resin.

(none)

Claims (13)

A method for purifying bis-2-hydroxyethyl terephthalate, comprising the following steps: 1) Mix bis-2-hydroxyethyl terephthalate and ethanol; 2) Inducing crystals from the mixture of step 1; and 3) The bis-2-hydroxyethyl terephthalate crystals produced in step 2 are recovered. As in the method of claim 1, Therein the bis-2-hydroxyethyl terephthalate is mixed so that one concentration in ethanol is 0.1 to 1 kg/L. As in the method of claim 1, Wherein this step 1 is carried out at 50 to 70°C. As in the method of claim 1, Wherein this step 2 is carried out by cooling the mixture of step 1 to 10°C to 30°C. As in the method of claim 1, Wherein this step 2 is carried out by adding a seed crystal to the mixture of step 1 to induce crystals. According to the method of claim 5, Wherein the seed crystal in step 2 is bis-2-hydroxyethyl terephthalate crystal. As in the method of claim 1, It further comprises a step of washing or drying the bis-2-hydroxyethyl terephthalate crystals recovered in step 3. As in the method of claim 1, Wherein the mother liquor recovered in step 3 was purified and then reused in step 1. A polyester copolymer obtained by purifying bis-2-hydroxyethyl terephthalate, dicarboxylic acid or derivatives thereof and containing ethylene glycol by the purification method as claimed in any one of claims 1 to 8 and comonomers are obtained by copolymerization of diols, and the polyester copolymer has a structure in which the moiety derived from the bis-2-hydroxyethyl terephthalate, derived from the dicarboxylic acid or its the acid moiety of the derivative and the diol moiety derived from the diol are repeating, wherein the polyester copolymer comprises 1 to 90 wt% of the moiety derived from bis-2-hydroxyethyl terephthalate. As in the polyester copolymer of claim 9, Wherein the comonomer is cyclohexanedimethanol or isosorbide. As in the polyester copolymer of claim 9, wherein the polyester copolymer has an intrinsic viscosity of one of 0.50 to 1.0 dl/g. As in the polyester copolymer of claim 9, Wherein the one of (Hunter L value) - (Hunter b value) measured on a 6 mm thick sample of the polyester copolymer was 87 or more. A product comprising the polyester copolymer of claim 9.