Polyester resin using recycled compounds and method for producing same

Abstract

The present invention relates to a polyester resin using recycled compounds and a method for producing the same. The present invention provides a method for producing a polyester resin of excellent quality while using recycled compounds as raw materials to minimize the use of petroleum-based compounds, which is advantageous for achieving environmental sustainability.

Description

[Technical Field]

[0001] The present invention relates to a polyester resin using a recycled compound and a method for producing the same. [Background technology]

[0002] A variety of methods have been proposed for the production of polyester resins. Among these, the most representative methods for industrial production of polyester resins are the direct esterification method between terephthalic acid and ethylene glycol (also known as the TPA method) and the transesterification method between dimethyl terephthalate and ethylene glycol (also known as the DMT method).

[0003] In the TPA method, excess ethylene glycol is used to react with terephthalic acid, and the esterification reaction proceeds for a long period of time under high temperature and pressure. During this process, the reaction between terephthalic acid and ethylene glycol produces the intermediate bis(2-hydroxyethyl) terephthalate (hereinafter, BHET). Prolonged esterification reaction under high temperature and pressure to produce the intermediate BHET consumes a lot of energy, and excess ethylene glycol that does not participate in the reaction is converted into the by-product diethylene glycol (DEG), resulting in a deterioration in the quality of the polyester resin.

[0004] The DMT method allows transesterification to proceed under milder conditions than the TPA method, but requires a long reaction time, limiting energy savings. Furthermore, methanol produced by the reaction of dimethyl terephthalate with ethylene glycol is a hazardous substance and is difficult to handle.

[0005] Meanwhile, recycling waste plastics has been attracting attention as a way to reduce dependence on fossil fuels and resolve environmental pollution issues through long-term low-carbon power generation strategies (LEDS). One proposed method involves depolymerizing polyethylene terephthalate (PET) or glycol-modified polyethylene terephthalate (PETG) to obtain chemically regenerated bis(2-hydroxyethyl) terephthalate (r-BHET), which can then be used as a raw material for the production of polyester resins.

[0006] However, when r-BHET is dissolved in water to produce polyester resins, r-BHET is converted into terephthalic acid and ethylene glycol by hydrolysis, and the polyester resins produced using this solution contain a large amount of by-products (e.g., diethylene glycol), resulting in a decrease in color quality.

[0007] Furthermore, when ethylene glycol is used to dissolve r-BHET for the production of polyester resins, excess ethylene glycol increases the production of the by-product diethylene glycol, resulting in a deterioration in the quality of the polyester resin.

[0008] Furthermore, if more ethylene glycol than necessary is applied to the reaction system, not only is it contrary to the environmental sustainability objective of minimizing the use of petroleum-based compounds, but energy consumption for removing the excess ethylene glycol increases, and if the excess ethylene glycol is not removed from the reaction system, it can cause process problems such as clogged pipes and reduced vacuum in the polyester resin production process.

[0009] Ultimately, the process of recycling waste plastics creates a contradiction in that carbon emissions increase, and there is also the limitation that it is difficult to produce high-quality polyester resins using recycled raw materials. Summary of the Invention [Problem to be solved by the invention]

[0010] The present invention seeks to provide a method for producing polyester resins of excellent quality while being advantageous in achieving environmental sustainability by using recycled compounds as raw materials and minimizing the use of petroleum-based compounds.

[0011] The present invention also provides a polyester resin obtained by the above-mentioned production method using a recycled compound as a raw material. [Means for solving the problem]

[0012] According to one embodiment of the invention, Heating the chemically regenerated bis(2-hydroxyethyl) terephthalate to prepare a melt; heating the composition comprising the melt and an esterification catalyst to form an oligomer; polycondensing the oligomer to prepare a polyester resin; A method for producing a polyester-based resin is provided, comprising:

[0013] According to another embodiment of the invention, The polyester resin obtained by the method for producing a polyester resin is provided by using a melt of chemically regenerated bis(2-hydroxyethyl) terephthalate.

[0014] The polyester resin and the method for producing the same according to the embodiment of the present invention will be described in more detail below.

[0015] Unless expressly stated otherwise herein, terminology is for the purpose of referring to particular embodiments only and is not intended to be limiting of the invention.

[0016] As used herein, the singular forms include the plural forms unless the context clearly dictates to the contrary.

[0017] As used herein, the meaning of "comprise" is to embody certain properties, regions, integers, steps, operations, elements and / or components, but does not exclude the presence or addition of other certain properties, regions, integers, steps, operations, elements, components and / or groups.

[0018] In this specification, the term "polyester-based resin" is used as a general term to include polyester homopolymers and polyester copolymers, i.e., the polyester-based resin may be a polyester homopolymer, a polyester copolymer, or a mixture thereof.

[0019] Chemically regenerated bis(2-hydroxyethyl) terephthalate (r-BHET) can be obtained by depolymerization (e.g., glycolysis) of waste plastics. When r-BHET is used as a raw material to produce polyester resins, dissolving r-BHET in water results in hydrolysis of r-BHET, converting it to terephthalic acid and ethylene glycol. The resulting polyester resins contain large amounts of by-products (e.g., diethylene glycol), resulting in poor color quality. Furthermore, dissolving r-BHET in ethylene glycol to produce polyester resins increases the production of the by-product diethylene glycol, resulting in poor quality of the polyester resin. Furthermore, adding more ethylene glycol than necessary to the reaction system not only violates environmental sustainability principles that aim to minimize the use of petroleum-based compounds, but also increases energy consumption to remove the excess ethylene glycol. Furthermore, if excess ethylene glycol is not removed from the reaction system, it can cause process problems such as pipe clogging and reduced vacuum during the polyester resin production process. Ultimately, this creates a contradiction in that carbon emissions increase during the process of recycling waste plastics, limiting the ability to produce high-quality polyester resins using recycled raw materials.

[0020] However, as a result of the research conducted by the present inventors, it has been found that the use of r-BHET melt in the production of polyester resins overcomes the limitations of the use of water or ethylene glycol and is advantageous in achieving environmental sustainability.

[0021] According to one embodiment of the invention, heating r-BHET to prepare a melt; heating the composition comprising the melt and an esterification catalyst to form an oligomer; polycondensing the oligomer to prepare a polyester resin; A method for producing a polyester-based resin is provided, comprising:

[0022] Hereinafter, each step included in the method for producing a polyester resin according to the embodiment will be described in detail.

[0023] First, a step of preparing a r-BHET melt is carried out.

[0024] The r-BHET melt is prepared by applying heat to solid r-BHET to convert it into a liquid state. Because the r-BHET melt does not contain water, hydrolysis of r-BHET can be prevented. Furthermore, because the r-BHET melt does not contain ethylene glycol, the use of petroleum-based compounds in the reaction system can be minimized.

[0025] The source of the r-BHET is not particularly limited, and it can be obtained by chemical recycling of polyethylene terephthalate (PET) or glycol-modified polyethylene terephthalate (PETG).

[0026] The melting point of r-BHET varies depending on its purity. Therefore, the heating temperature for preparing the r-BHET melt can be determined by taking into account the melting point of pure BHET (106°C to 109°C) and the temperature at which pure BHET begins to thermally decompose (203°C). For example, the heating temperature can be selected from the range of 109°C to 203°C. For the formation of the r-BHET melt, the heating temperature is preferably 109°C or higher. However, if the heating temperature is too high, r-BHET is converted into terephthalic acid and ethylene glycol by thermal decomposition. The polyester resin produced using the r-BHET contains a large amount of by-products (e.g., diethylene glycol) and suffers from poor color quality. Therefore, the heating temperature is preferably 203°C or lower.

[0027] The r-BHET melt is prepared by melting r-BHET in a melting facility and then introduced into a reactor. The melting facility may be a melting tank or a melting kneader. When preparing a polyester copolymer, the order in which the r-BHET melt and the co-reactant are introduced into the reactor is not particularly limited. For example, the r-BHET melt may be introduced into the reactor after the co-reactant is introduced. For another example, the co-reactant may be introduced into the reactor before the r-BHET melt is introduced.

[0028] Next, the composition containing the r-BHET melt and the esterification catalyst is heated to form oligomers.

[0029] According to one embodiment, the esterification catalyst may be phosphoric acid or an organic phosphate. As a non-limiting example, the esterification catalyst may be one or more compounds selected from the group consisting of phosphoric acid, triphenyl phosphate, trimethyl phosphate, triethyl phosphate, and triethyl phosphonoacetate.

[0030] The esterification catalyst may be added in an amount of 10 ppm to 500 ppm based on 1 kg of the final polyester resin.

[0031] According to one embodiment, the composition containing the r-BHET melt and the esterification catalyst may further contain one or more compounds selected from the group consisting of compounds having two or more carboxylic acid functional groups and compounds having two or more hydroxy functional groups.

[0032] The compound having two or more carboxylic acid functional groups and the compound having two or more hydroxy functional groups may be included in the composition as co-reactants.

[0033] The content of the co-reactant can be determined in consideration of the efficiency of the esterification reaction and the physical properties of the polyester resin. Preferably, the composition contains 0.01 to 9.5 moles of the co-reactant, or 0.1 to 9.5 moles, or 1 to 9 moles, or 2 to 9 moles, based on 1 mole of the r-BHET.

[0034] As the co-reactant, compounds known to be usable in the production of polyester resins can be used without any particular limitation.

[0035] Preferably, the compound having two or more carboxylic acid functional groups is phthalic acid, isophthalic acid, terephthalic acid, 2,6-naphthalenedicarboxylic acid, biphenyl-4,4'-dicarboxylic acid, 4,4'-cis-stilbenedicarboxylic acid, 2,5-furandicarboxylic acid, 2,5-thiophenedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, ethanedioic acid (oxalic acid), propanedioic acid (malonic acid), fumaric acid, maleic acid (maleic acid), or the like. The acid may be one or more compounds selected from the group consisting of pentanedioic acid (pentanedioic acid; glutaric acid), octanedioic acid (octanedioic acid; suberic acid), decanedioic acid (decanediol; sebacic acid), adipic acid, succinic acid, tricarboxylic acid, trimellitic acid, hemimellitic acid, hemimellitic anhydride, trimesic acid, and tricarballylic acid.

[0036] The compound having two or more hydroxy functional groups is ethylene glycol (ethylene glycol glycol), 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, cyclopentanediol, 1,4-cyclohexanediol, 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, 2,2,4-trimethyl-1,3-pentanediol,The surfactant may be one or more compounds selected from the group consisting of 3-pentanediol, polyethylene glycol, neopentyl glycol, dipropylene glycol, triethylene glycol, polypropylene glycol, hexylene glycol, pentaethylene glycol, polytetramethylene glycol, dihydroxybenzene, dihydroxy naphthalene, hydroxyquinol, glycerin, pentaerythritol, trimethylol propane, trimethylol ethane, and isosorbide.

[0037] The co-reactant may be added to the reactor in its original state, without being dissolved in water or an organic solvent. The co-reactant added to the reactor melts at the reaction temperature. If the co-reactant is added in the form of a solution dissolved in water or an organic solvent, the temperature of the reactor drops significantly, and additional energy is consumed to raise the temperature again. In particular, if the co-reactant is added in the form of a solution dissolved in water or an organic solvent, the effect of applying the r-BHET melt of the present invention may be hindered.

[0038] The reaction conditions for the step of producing the oligomer can be determined in consideration of the efficiency of the esterification reaction. Preferably, the step of producing the oligomer is carried out under a pressure of 1.0 kgf / cm. 2 ~3.0kgf / cm 2The esterification reaction may be carried out under a pressure of 100° C. or more and a temperature of 150° C. to 260° C. The time for the esterification reaction can be determined within an appropriate range depending on the amounts and ratios of the raw material compounds, and the temperature and pressure conditions.

[0039] The oligomer production step may be carried out in a batch reactor or a continuous reactor. The r-BHET melt and other raw materials are separately charged into the reactor. By-products (water) and by-reactants generated in the esterification reaction are preferably removed from the system under low vacuum or using a rectifying column.

[0040] Next, the oligomer is polycondensed to prepare a polyester resin.

[0041] The condensation polymerization may be carried out in the presence of a condensation polymerization catalyst. For example, the condensation polymerization may be carried out in the presence of one or more compounds selected from the group consisting of antimony triacetate, antimony trioxide, antimony tricarbonate, antimony glycolate, titanium oxide, titanium chelate compounds, tetra-n-propyl titanate, tetra-isopropyl titanate, tetra-n-butyl titanate, tetra-isobutyl titanate, butyl-isopropyl titanate, and germanium dioxide. The condensation polymerization catalyst may be added in an amount of 50 ppm to 600 ppm of antimony, titanium, or germanium atomic content per 1 kg of the final polyester resin.

[0042] The conditions for the polycondensation can be determined in consideration of the efficiency of the polycondensation reaction. Preferably, the polycondensation reaction may be carried out under a pressure of 0.01 torr to 10 torr and at a temperature of 150°C to 350°C. The time for the polycondensation reaction can be determined within an appropriate range depending on the amounts and ratios of the raw material compounds, and the temperature and pressure conditions.

[0043] As such, the polyester resin manufacturing method uses the recycled compound r-BHET as a raw material, minimizes the use of petroleum-based co-reactants, and reduces energy consumption, which is advantageous for achieving environmental sustainability. Furthermore, the polyester resin manufacturing method can prevent process problems (e.g., pipe clogging and reduced vacuum) caused by the use of excess ethylene glycol.

[0044] According to another embodiment of the invention, there is provided a polyester resin obtained by the method for producing a polyester resin using a melt of chemically recycled bis(2-hydroxyethyl) terephthalate.

[0045] The polyester resin is obtained by using chemically recycled bis(2-hydroxyethyl) terephthalate (hereinafter, referred to as r-BHET) as a raw material. Preferably, the polyester resin is obtained by the above-described production method.

[0046] The polyester resin can have excellent quality since it is obtained by using r-BHET as a raw material, minimizing the use of petroleum-based co-reactants.

[0047] For example, the polyester resin may have an intrinsic viscosity of 0.45 to 0.85 dL / g. The intrinsic viscosity of the polyester resin may be measured at room temperature (about 25°C) using a conventional device such as an Ostwald viscosimeter.

[0048] Specifically, the polyester resin may have an intrinsic viscosity of 0.45 dL / g or more, alternatively 0.50 dL / g or more, alternatively 0.55 dL / g or more, and 0.85 dL / g or less, alternatively 0.80 dL / g or less, alternatively 0.75 dL / g or less. Preferably, the polyester resin may have an intrinsic viscosity of 0.45 to 0.85 dL / g, alternatively 0.50 to 0.85 dL / g, alternatively 0.50 to 0.80 dL / g, alternatively 0.55 to 0.80 dL / g, alternatively 0.55 to 0.75 dL / g.

[0049] As another example, when an excess amount of ethylene glycol is used in the reaction system during the production of a polyester resin, the amount of diethylene glycol (DEG) produced as a by-product increases, resulting in a deterioration in the quality of the polyester resin.

[0050] However, the polyester-based resin according to an embodiment of the present invention can be produced without using more ethylene glycol than necessary in the reaction with the co-reactant in the reaction system, thereby minimizing the content of by-products contained in the polyester-based resin. Preferably, the polyester-based resin may contain the by-product diethylene glycol in an amount of less than 4.0 wt%, or 0.1 wt% to 4.0 wt%, or 0.5 wt% to 3.0 wt%, or 0.5 wt% to 2.0 wt%, or 0.5 wt% to 1.0 wt%, based on the weight of the polyester-based resin.

[0051] As another example, r-BHET is obtained from waste plastic through various chemical steps, and when it is used as a raw material to produce polyester resin, the color quality deteriorates.

[0052] However, the polyester resin has a L measured by a spectrophotometer on a test piece made of the polyester resin. * a * b *According to the color system (CIE LAB), color b is less than 6.0, or 3.0 to 5.5, or 3.0 to 5.0, or 3.5 to 5.0 * It can have a value.

[0053] Said L * a * b * In the color system, L * The value indicates the brightness. * If = 0, it is black, and L * If a = 100, it indicates white. * The value indicates whether the color is biased towards red or green. * If the value is negative, the color is biased towards green, and * If the value is positive, the color is biased towards red. * The value indicates whether the color is biased toward yellow or blue. * If the value is negative, the color is biased towards blue, and b * If the value is positive, the color is biased towards yellow. * value and b * The closer the value is to 0, the closer the color is to white. [Effects of the Invention]

[0054] The present invention provides a method for producing polyester resins of excellent quality while being advantageous in achieving environmental sustainability by using recycled compounds as raw materials and minimizing the use of petroleum-based compounds. DETAILED DESCRIPTION OF THE INVENTION

[0055] Preferred examples are presented below to aid in understanding the invention, but the following examples are merely for illustrative purposes and are not intended to limit the scope of the invention.

[0056] Example 1 r-BHET was melted using a melting facility to prepare a r-BHET melt.

[0057] 5.2 moles of the r-BHET melt was charged into an esterification reactor under heating, and phosphoric acid was added at 150° C. The phosphoric acid was added in an amount of 100 ppm based on 1 kg of the final polyester resin.

[0058] The temperature was raised to 180°C for 30 minutes, and the pressure was 1.0 kgf / cm 2 The esterification reaction was carried out at 180°C for 1 hour to form oligomers. During this process, by-products (water) and by-reaction products were removed from the system.

[0059] Next, the oligomer was subjected to polycondensation in a polycondensation reactor at 0.3 torr and 280°C in the presence of antimony trioxide to produce a polyester resin (intrinsic viscosity: 0.64 dL / g, polymerization time: 98 minutes). The antimony trioxide was added in an amount of 300 ppm antimony atom per kg of the final polyester resin.

[0060] Example 2 r-BHET was melted using a melting facility to prepare a r-BHET melt.

[0061] The r-BHET melt, adipic acid, and ethylene glycol were charged into an esterification reactor through separate inlets under heating (r-BHET 1.66 mol: adipic acid 7.50 mol: ethylene glycol 7.50 mol). Then, phosphoric acid was added at 150°C. The phosphoric acid was added at a phosphoric acid content of 100 ppm based on 1 kg of the final polyester resin.

[0062] The temperature was raised to 180°C for 30 minutes, and the pressure was 1.0 kgf / cm 2 The esterification reaction was carried out at 180°C for 2 hours to produce oligomers. During this process, by-products (water) and by-reaction products were removed from the system.

[0063] Next, the oligomer was subjected to polycondensation in a polycondensation reactor at 0.3 torr and 280°C in the presence of antimony trioxide to produce a polyester resin (intrinsic viscosity: 0.62 dL / g, polymerization time: 110 minutes). The antimony trioxide was added in an amount of 300 ppm antimony atom content based on 1 kg of the final polyester resin.

[0064] Example 3 r-BHET was melted using a melting facility to prepare a r-BHET melt.

[0065] The r-BHET melt, isophthalic acid, and ethylene glycol were charged into an esterification reactor through separate inlets under heating (r-BHET 3.08 mol: isophthalic acid 3.08 mol: ethylene glycol 3.08 mol). Then, phosphoric acid was added at 150°C. The phosphoric acid was added in an amount of 100 ppm based on 1 kg of the final polyester resin.

[0066] The temperature was raised to 180°C for 30 minutes, and the pressure was 1.0 kgf / cm 2 The esterification reaction was carried out at 180°C for 2 hours to produce an oligomer. During this process, by-products (water) and by-reaction products were removed from the system.

[0067] Next, the oligomer was subjected to polycondensation in a polycondensation reactor at 0.3 torr and 280°C to produce a polyester resin (intrinsic viscosity: 0.65 dL / g, polymerization time: 125 minutes). The antimony trioxide was added in an amount of 300 ppm of antimony atom per kg of the final polyester resin.

[0068] Example 4 r-BHET was melted using a melting facility to prepare a r-BHET melt.

[0069] The r-BHET melt, adipic acid, isophthalic acid, and ethylene glycol were charged into an esterification reactor through separate inlets under heating (r-BHET 2.10 mol: adipic acid 2.45 mol: isophthalic acid 2.44 mol: ethylene glycol 4.89 mol). Then, phosphoric acid was charged at 150°C. The phosphoric acid was added at a phosphoric acid content of 100 ppm based on 1 kg of the final polyester resin.

[0070] The temperature was raised to 180°C for 30 minutes, and the pressure was 1.0 kgf / cm 2 The esterification reaction was carried out at 180°C for 2 hours to produce an oligomer. During this process, by-products (water) and by-reaction products were removed from the system.

[0071] Next, the oligomer was subjected to polycondensation in a polycondensation reactor in the presence of antimony trioxide at 0.3 torr and 280°C to produce a polyester resin (intrinsic viscosity: 0.60 dL / g, polymerization time: 121 minutes). Antimony trioxide was added in an amount of 300 ppm antimony atom content based on 1 kg of the final polyester resin.

[0072] Example 5 r-BHET was melted using a melting facility to prepare a r-BHET melt.

[0073] The r-BHET melt, terephthalic acid, and neopentyl glycol were charged into an esterification reactor through separate inlets under heating (r-BHET 2.00 mol: terephthalic acid 4.66 mol: neopentyl glycol 4.66 mol). Then, phosphoric acid was added at 150°C. The phosphoric acid was added in an amount of 100 ppm based on 1 kg of the final polyester resin.

[0074] The temperature was raised to 180°C for 30 minutes, and the pressure was 1.0 kgf / cm 2 The esterification reaction was carried out at 180°C for 2 hours to produce an oligomer. During this process, by-products (water) and by-reaction products were removed from the system.

[0075] Next, the oligomer was subjected to polycondensation in a polycondensation reactor at 0.3 torr and 280°C to produce a polyester resin (intrinsic viscosity: 0.61 dL / g, polymerization time: 113 minutes). The antimony trioxide was added in an amount of 300 ppm of antimony atom per kg of the final polyester resin.

[0076] Example 6 r-BHET was melted using a melting facility to prepare a r-BHET melt.

[0077] The r-BHET melt, terephthalic acid, and isosorbide were charged into an esterification reactor through separate inlets under heating (r-BHET 2.00 mol: terephthalic acid 4.66 mol: isosorbide 4.66 mol). Then, phosphoric acid was added at 150°C. The phosphoric acid was added in an amount of 100 ppm based on 1 kg of the final polyester resin.

[0078] The temperature was raised to 180°C for 30 minutes, and the pressure was 1.0 kgf / cm 2 The esterification reaction was carried out at 180°C for 2 hours to produce an oligomer. During this process, by-products (water) and by-reaction products were removed from the system.

[0079] Next, the oligomer was subjected to polycondensation in a polycondensation reactor at 0.3 torr and 280°C to produce a polyester resin (intrinsic viscosity: 0.66 dL / g, polymerization time: 115 minutes). The antimony trioxide was added in an amount of 300 ppm of antimony atom per kg of the final polyester resin.

[0080] Example 7 r-BHET was melted using a melting facility to prepare a r-BHET melt.

[0081] The r-BHET melt, 2,5-furandicarboxylic acid, and ethylene glycol (2.09 mol of r-BHET, 4.89 mol of 2,5-furandicarboxylic acid, and 4.89 mol of ethylene glycol) were added to an esterification reactor through separate inlets under heating. Then, phosphoric acid was added at 150°C. The phosphoric acid was added in an amount of 100 ppm based on 1 kg of the final polyester resin.

[0082] The temperature was raised to 180°C for 30 minutes, and the pressure was 1.0 kgf / cm 2 The esterification reaction was carried out at 180°C for 2 hours to produce an oligomer. During this process, by-products (water) and by-reaction products were removed from the system.

[0083] Next, the oligomer was subjected to polycondensation in a polycondensation reactor at 0.3 torr and 280°C to produce a polyester resin (intrinsic viscosity: 0.65 dL / g, polymerization time: 112 minutes). The antimony trioxide was added in an amount of 300 ppm of antimony atom per kg of the final polyester resin.

[0084] Example 8 r-BHET was melted using a melting facility to prepare a r-BHET melt.

[0085] The r-BHET melt, terephthalic acid, and 1,4-cyclohexanedimethanol were charged into an esterification reactor through separate inlets under heating (r-BHET 2.00 mol: terephthalic acid 4.66 mol: 1,4-cyclohexanedimethanol 4.66 mol). Phosphoric acid was then added at 150°C. The phosphoric acid was added at a phosphoric acid content of 100 ppm per kg of the final polyester resin.

[0086] The temperature was raised to 180°C for 30 minutes, and the pressure was 1.0 kgf / cm 2 The esterification reaction was carried out at 180°C for 2 hours to produce an oligomer. During this process, by-products (water) and by-reaction products were removed from the system.

[0087] Next, the oligomer was subjected to polycondensation in a polycondensation reactor at 0.3 torr and 280°C to produce a polyester resin (intrinsic viscosity: 0.63 dL / g, polymerization time: 114 minutes). The antimony trioxide was added in an amount of 300 ppm of antimony atom per kg of the final polyester resin.

[0088] Comparative Example 1 r-BHET and water (W) were mixed to prepare an r-BHET solution with a concentration of 50 wt %.

[0089] The r-BHET solution (5.2 mol of r-BHET) was added to an esterification reactor under heating, and phosphoric acid was then added at 150° C. The phosphoric acid was added in an amount of 100 ppm based on 1 kg of the final polyester resin.

[0090] The temperature was raised to 180°C for 30 minutes, and the pressure was 1.0 kgf / cm 2 The esterification reaction was carried out at 180°C for 1 hour to form oligomers. During this process, by-products (water) and by-reaction products were removed from the system.

[0091] Next, the oligomer was subjected to polycondensation in a polycondensation reactor at 0.3 torr and 280°C in the presence of antimony trioxide to produce a polyester resin (intrinsic viscosity: 0.61 dL / g, polymerization time: 168 minutes). Antimony trioxide was added in an amount of 300 ppm antimony atom content based on 1 kg of the final polyester resin.

[0092] Comparative Example 2 r-BHET and water (W) were mixed to prepare an 80 wt % r-BHET solution.

[0093] The r-BHET solution (5.2 mol of r-BHET) was added to an esterification reactor under heating, and phosphoric acid was then added at 150° C. The phosphoric acid was added in an amount of 100 ppm based on 1 kg of the final polyester resin.

[0094] The temperature was raised to 180°C for 30 minutes, and the pressure was 1.0 kgf / cm 2 The esterification reaction was carried out at 180°C for 1 hour to form oligomers. During this process, by-products (water) and by-reaction products were removed from the system.

[0095] Next, the oligomer was subjected to polycondensation in a polycondensation reactor at 0.3 torr and 280°C in the presence of antimony trioxide to produce a polyester resin (intrinsic viscosity: 0.64 dL / g, polymerization time: 180 minutes). The antimony trioxide was added in an amount of 300 ppm of antimony atom per kg of the final polyester resin.

[0096] Comparative Example 3 r-BHET and ethylene glycol (EG) were mixed to prepare a 50 wt % r-BHET solution.

[0097] The r-BHET solution (5.2 mol of r-BHET) was added to an esterification reactor under heating, and phosphoric acid was then added at 150° C. The phosphoric acid was added in an amount of 100 ppm based on 1 kg of the final polyester resin.

[0098] The temperature was raised to 180°C for 30 minutes, and the pressure was 1.0 kgf / cm 2 The esterification reaction was carried out at 180°C for 1 hour to produce an oligomer. During this process, by-products (water) and by-reaction products were removed from the system.

[0099] Next, the oligomer was subjected to polycondensation in a polycondensation reactor at 0.3 torr and 280°C to produce a polyester resin (intrinsic viscosity: 0.68 dL / g, polymerization time: 165 minutes). The antimony trioxide was added in an amount of 300 ppm of antimony atom per kg of the final polyester resin.

[0100] Comparative Example 4 r-BHET and ethylene glycol (EG) were mixed to prepare an 80 wt % r-BHET solution.

[0101] The r-BHET solution (5.2 mol of r-BHET) was added to an esterification reactor under heating, and phosphoric acid was then added at 150° C. The phosphoric acid was added in an amount of 100 ppm based on 1 kg of the final polyester resin.

[0102] The temperature was raised to 180°C for 30 minutes, and the pressure was 1.0 kgf / cm 2 The esterification reaction was carried out at 180°C for 1 hour to produce an oligomer. During this process, the by-product (water) and by-reaction products were removed from the system.

[0103] Next, the oligomer was subjected to polycondensation in a polycondensation reactor at 0.3 torr and 280°C in the presence of antimony trioxide to produce a polyester resin (intrinsic viscosity: 0.64 dL / g, polymerization time: 180 minutes). The antimony trioxide was added in an amount of 300 ppm of antimony atom per kg of the final polyester resin.

[0104] Comparative Example 5 r-BHET and water (W) were mixed to prepare an r-BHET solution with a concentration of 50 wt %.

[0105] The r-BHET solution, adipic acid, and ethylene glycol (2.21 mol of r-BHET, 5.15 mol of adipic acid, and 5.15 mol of ethylene glycol) were added to the esterification reactor through separate inlets under heating. Then, phosphoric acid was added at 150°C. The phosphoric acid was added at a phosphoric acid content of 100 ppm based on 1 kg of the final polyester resin.

[0106] The temperature was raised to 180°C for 30 minutes, and the pressure was 1.0 kgf / cm 2 The esterification reaction was carried out at 180°C for 2 hours to produce an oligomer. During this process, by-products (water) and by-reaction products were removed from the system.

[0107] Next, the oligomer was subjected to polycondensation in a polycondensation reactor at 0.3 torr and 280°C to produce a polyester resin (intrinsic viscosity: 0.66 dL / g, polymerization time: 210 minutes). The antimony trioxide was added in an amount of 300 ppm of antimony atom per kg of the final polyester resin.

[0108] Comparative Example 6 r-BHET and water (W) were mixed to prepare a 50 wt % r-BHET solution.

[0109] The r-BHET solution, isophthalic acid, and ethylene glycol were charged into an esterification reactor through separate inlets under heating (r-BHET 1.19 mol: isophthalic acid 4.66 mol: ethylene glycol 4.66 mol). Then, phosphoric acid was charged at 150°C. The phosphoric acid was added in an amount of 100 ppm based on 1 kg of the final polyester resin.

[0110] The temperature was raised to 180°C for 30 minutes, and the pressure was 1.0 kgf / cm 2 The esterification reaction was carried out at 180°C for 2 hours to produce oligomers. During this process, by-products (water and methanol) and by-reactants were removed from the system.

[0111] Next, the oligomer was subjected to polycondensation in a polycondensation reactor at 0.3 torr and 280°C to produce a polyester resin (intrinsic viscosity: 0.63 dL / g, polymerization time: 193 minutes). The antimony trioxide was added in an amount of 300 ppm of antimony atom per kg of the final polyester resin.

[0112] Comparative Example 7 r-BHET and ethylene glycol (EG) were mixed to prepare a 50 wt % r-BHET solution.

[0113] The r-BHET solution, adipic acid, and ethylene glycol (2.21 mol of r-BHET, 5.15 mol of adipic acid, and 5.15 mol of ethylene glycol) were added to the esterification reactor through separate inlets under heating. Then, phosphoric acid was added at 150°C. The phosphoric acid was added at a phosphoric acid content of 100 ppm based on 1 kg of the final polyester resin.

[0114] The temperature was raised to 180°C for 30 minutes, and the pressure was 1.0 kgf / cm 2The esterification reaction was carried out at 180°C for 2 hours to produce an oligomer. During this process, by-products (water) and by-reaction products were removed from the system.

[0115] Next, the oligomer was subjected to polycondensation in a polycondensation reactor at 0.3 torr and 280°C in the presence of antimony trioxide to produce a polyester resin (intrinsic viscosity: 0.67 dL / g, polymerization time: 200 minutes). The antimony trioxide was added in an amount of 300 ppm of antimony atom per kg of the final polyester resin.

[0116] Comparative Example 8 r-BHET and ethylene glycol (EG) were mixed to prepare a 50 wt % r-BHET solution.

[0117] The r-BHET solution, isophthalic acid, and ethylene glycol were charged into an esterification reactor through separate inlets under heating (r-BHET 1.19 mol: isophthalic acid 4.66 mol: ethylene glycol 4.66 mol). Then, phosphoric acid was charged at 150°C. The phosphoric acid was added in an amount of 100 ppm based on 1 kg of the final polyester resin.

[0118] The temperature was raised to 180°C for 30 minutes, and the pressure was 1.0 kgf / cm 2 The esterification reaction was carried out at 180°C for 2 hours to produce oligomers. During this process, by-products (water and methanol) and by-reactants were removed from the system.

[0119] Next, the oligomer was subjected to polycondensation in a polycondensation reactor at 0.3 torr and 280°C to produce a polyester resin (intrinsic viscosity: 0.68 dL / g, polymerization time: 190 minutes). The antimony trioxide was added in an amount of 300 ppm of antimony atom per kg of the final polyester resin.

[0120] Comparative Example 9 r-BHET and water (W) were mixed to prepare an r-BHET solution with a concentration of 50 wt %.

[0121] The r-BHET solution, dimethyl terephthalate, and isosorbide were charged into an esterification reactor through separate inlets under heating (r-BHET 3.08 mol: dimethyl terephthalate 3.08 mol: isosorbide 3.08 mol). Then, phosphoric acid was added at 150°C. The phosphoric acid was added in an amount of 100 ppm based on 1 kg of the final polyester resin.

[0122] The temperature was raised to 180°C for 30 minutes, and the pressure was 1.0 kgf / cm 2 The esterification reaction was carried out at 180°C for 2 hours to produce oligomers. During this process, by-products (water and methanol) and by-reaction products were removed from the system.

[0123] Next, the oligomer was subjected to condensation polymerization in a condensation polymerization reactor at 0.3 torr and 280°C for 205 minutes to produce a polyester resin (intrinsic viscosity: 0.66 dL / g, polymerization time: 205 minutes). Antimony trioxide was added to give an antimony atom content of 300 ppm based on 1 kg of the final polyester resin.

[0124] Comparative Example 10 r-BHET and ethylene glycol (EG) were mixed to prepare a 50 wt % r-BHET solution.

[0125] The r-BHET solution, dimethyl terephthalate, and isosorbide were charged into an esterification reactor through separate inlets under heating (r-BHET 3.08 mol: dimethyl terephthalate 3.08 mol: isosorbide 3.08 mol). Then, phosphoric acid was added at 150°C. The phosphoric acid was added in an amount of 100 ppm based on 1 kg of the final polyester resin.

[0126] The temperature was raised to 180°C for 30 minutes, and the pressure was 1.0 kgf / cm 2 The esterification reaction was carried out at 180°C for 3 hours to produce oligomers. During this process, by-products (water and methanol) and by-reactants were removed from the system.

[0127] Next, the oligomer was subjected to polycondensation in a polycondensation reactor at 0.3 torr and 280°C for 213 minutes to produce a polyester resin (intrinsic viscosity: 0.63 dL / g, polymerization time: 213 minutes). The antimony trioxide was added in an amount of 300 ppm of antimony atom per kg of the final polyester resin.

[0128] Test Example 1) Intrinsic viscosity of polyester resin The intrinsic viscosity of the polyester resin was measured at room temperature (about 25° C.) using an Ostwald viscosimeter.

[0129] A sample of polyester resin dissolved in a solvent (2-chlorophenol) at a concentration of 0.4 g / 100 ml was transferred to an Ostwald viscometer. The number of seconds it took for the sample to fall was measured using the viscometer and an aspirator. The number of seconds it took for the solvent to fall was also measured in a similar manner. The intrinsic viscosity (IV) value of the polyester resin was calculated using the following equations 1 and 2. In the following equations, C is the concentration of the sample (g / 100 ml).

[0130] <Expression 1> Relative viscosity (RV) = [number of seconds for sample to fall] / [number of seconds for solvent to fall]

[0131] <Expression 2> Intrinsic viscosity (IV)=[1 / 4×(RV-1 / C)]+[3 / 4×(lnRV / C)]

[0132] 2) Diethylene glycol (DEG) content A 50 ml container was charged with 1 g of polyester resin and 3 ml of monoethanolamine, heated on a hot plate to completely dissolve the polyester resin, and then cooled to 100°C. A solution of 0.005 g of 1,6-hexanediol dissolved in 20 ml of methanol was added, followed by the addition of 10 g of terephthalic acid for neutralization. The resulting neutralized solution was filtered using a funnel and filter paper, and the diethylene glycol (DEG) content (wt%) of the filtrate was measured by gas chromatography (GC). GC analysis was performed using a Shimadzu Nexis GC-2030 GC analyzer, following the analyzer's manual.

[0133] 3) Color B * Measurement of values The polyester resin test piece was measured using a spectrophotometer (SE-2000, Nippon Denshoku Co.). * a * b * Color b according to the color system (CIE LAB) * The values ​​were measured.

[0134] [Table 1]

[0135] *AA: Adipic acid *EG: Ethylene glycol *IPA: Isophthalic acid *TPA: Terephthalic acid *NPG: Neopentyl glycol *ISB: Isosorbide *FDCA: 2,5-furandicarboxylic acid *CHDM: 1,4-cyclohexanedimethanol

[0136] [Table 2]

[0137] *AA: Adipic acid *EG: Ethylene glycol *IPA: Isophthalic acid *DMT: Dimethyl terephthalate *ISB: Isosorbide

[0138] Referring to the above examples and comparative examples, in the preparation method according to the examples, the content of by-products is low and the color b is close to 0 in a relatively short polycondensation reaction time. * It was confirmed that a polyester resin having the above values ​​could be obtained. Furthermore, in the manufacturing method of the example, since dimethyl terephthalate was not used, the harmful by-product methanol was not produced, and more ethylene glycol than necessary was not used in the reaction with the co-reactant in the reaction system, which was more advantageous in realizing environmental sustainability.

[0139] In contrast, the comparative example required a relatively long polycondensation reaction time, and produced a polyester resin with a high content of by-products and poor color quality.

[0140] Although the present invention has been described above using limited examples, the present invention is not limited thereto, and it goes without saying that various modifications and variations can be made by a person having ordinary skill in the art to which the present invention pertains within the technical spirit of the present invention and the scope of the claims set forth below.

Claims

1. Heating the chemically regenerated bis(2-hydroxyethyl) terephthalate to prepare a melt; heating the composition comprising the melt and an esterification catalyst to form an oligomer; polycondensing the oligomer to prepare a polyester resin; A method for producing a polyester resin, comprising:

2. The method for producing a polyester resin according to claim 1 , wherein the esterification reaction catalyst is phosphoric acid or an organic phosphate.

3. 2. The method for producing a polyester resin according to claim 1, wherein the composition comprising the melt and the esterification catalyst further comprises one or more co-reactants selected from the group consisting of compounds having two or more carboxylic acid functional groups and compounds having two or more hydroxy functional groups.

4. 4. The method for producing a polyester resin according to claim 3, wherein the composition comprises 0.01 mole to 9.5 moles of the co-reactant based on 1 mole of the chemically regenerated bis(2-hydroxyethyl) terephthalate.

5. The compound having two or more carboxylic acid functional groups includes phthalic acid, isophthalic acid, terephthalic acid, 2,6-naphthalenedicarboxylic acid, biphenyl-4,4'-dicarboxylic acid, 4,4'-cis-stilbenedicarboxylic acid, 2,5-furandicarboxylic acid, 2,5-thiophenedicarboxylic acid, and the like. acid), 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, ethanedioic acid, propanedioic acid, fumaric acid, maleic acid, pentanedioic acid, octanedioic acid, decanedioic acid, adipic acid, succinic acid 4. The method for producing a polyester resin according to claim 3, wherein the carboxylic acid is one or more compounds selected from the group consisting of carboxylic acid, tricarboxylic acid, trimellitic acid, hemimellitic acid, hemimellitic anhydride, trimesic acid, and tricarballylic acid.

6. The compound having two or more hydroxy functional groups includes ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, cyclopentanediol, 1 ,4-cyclohexanediol (1,4-cyclohexanediol), 1,2-cyclohexanedimethanol (1,2-cyclohexanedimethanol), 1,3-cyclohexanedimethanol (1,3-cyclohexanedimethanol), 1,4-cyclohexanedimethanol (1,4-cyclohexanedimethanol), 2,2,4-trimethyl-1,3-pentanediol (2,2,4-trimethyl-1,3-pentanediol, polyethylene glycol, neopentyl glycol, dipropylene glycol, triethylene glycol, polypropylene glycol, hexylene glycol, pentaethylene glycol, polytetramethylene glycol 5. The method for producing a polyester resin according to claim 3, wherein the hydroxybenzoate is at least one compound selected from the group consisting of hydroxybenzoates, hydroxybenzoates, hydroxynaphthalenes, hydroxyquinols, glycerin, pentaerythritol, trimethylolpropane, trimethylolethane, and isosorbide.

7. The step of preparing the oligomer is carried out under a pressure of 1.0 kgf / cm 2 ~3.0kgf / cm 2 2. The method for producing a polyester resin according to claim 1, wherein the process is carried out under a pressure of 1000 kJ / min and a temperature of 150°C to 260°C.

8. 10. The method of claim 1, wherein the step of preparing the polyester resin by condensation polymerization of the oligomer is performed under a pressure of 0.01 to 10 torr and a temperature of 150 to 350°C.

9. 2. The method for producing a polyester resin according to claim 1, wherein the condensation polymerization is carried out in the presence of one or more compounds selected from the group consisting of antimony triacetate, antimony trioxide, antimony tricarbonate, antimony glycolate, titanium oxide, a titanium chelate compound, tetra-n-propyl titanate, tetra-isopropyl titanate, tetra-n-butyl titanate, tetra-isobutyl titanate, butyl-isopropyl titanate, and germanium dioxide.

10. A polyester resin obtained by the method for producing a polyester resin according to claim 1, using a melt of chemically regenerated bis(2-hydroxyethyl) terephthalate.

11. The polyester resin according to claim 10, having an intrinsic viscosity of 0.45 to 0.85 dl / g.

12. 11. The polyester-based resin of claim 10, comprising less than 4.0 wt. % by weight of the by-product diethylene glycol, based on the weight of the polyester-based resin.

13. The L measured using a spectrophotometer for the test piece made of the polyester resin * a * b * Color b less than 6.0 according to the color system (CIE LAB) * The polyester resin according to claim 10, having a value.

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