Polyester copolymer having excellent strength and product comprising same

Abstract

The present application relates to a polyester copolymer having excellent strength and a product comprising the same. The polyester copolymer comprises residues of a dicarboxylic acid component comprising terephthalic acid and residues of a diol component comprising isosorbide, cyclohexanedimethanol, and a non-cyclic diol; the contents of the isosorbide residues, the cyclohexanedimethanol residues and the non-cyclic diol residues are 4 mol% to 20 mol%, 65 mol% to 85 mol% and 11 mol% to 31 mol% based on the total mole number of the diol component residues; the polyester copolymer satisfies the formula: 30 lt; (X * Y) / (Z * W) lt; x is the storage modulus (MPa) of the polyester copolymer at 40 DEG C, Y is the glass transition temperature (DEG C) of the polyester copolymer, Z is the melting point (DEG C) of the polyester copolymer, and W is the heat of fusion (J / g) of the polyester copolymer.

Description

[0001] This application is a divisional application of the application with the application number 202180072152.0 and the title “Polyester Copolymer with Excellent Strength and Product Containing the Same” filed on November 04, 2021. TECHNICAL FIELD

[0002] The present disclosure relates to a polyester copolymer with excellent strength, and a product containing the same. BACKGROUND

[0003] Polyesters have excellent mechanical strength, heat resistance, transparency, and gas barrier properties, and thus are most suitable as a material for beverage filling containers, packaging films, acoustic devices, video tapes, and the like, and are being used in large quantities. In addition, it is produced worldwide as an industrial material such as medical fibers or tire cords, and the like. Polyester sheets or polyester plates have good transparency and excellent mechanical strength, and thus are widely used as a material for boxes, cases, partitions, store shelves, protective plates, blister packs, building materials, interior and exterior materials, and the like.

[0004] Among them, polyesters are widely used to prepare food or beverage containers, but recently, there is a need for a polyester material that can be used in dishwashers and the like and withstand high pressure such as high pressure in a carbonated water container. Therefore, the polyester should have excellent pressure resistance properties and heat resistance properties. In general, the pressure resistance increases as the polyester has crystallinity and has a higher intrinsic viscosity, and as the crystallinity is higher, the stretch molding of the polyester is improved. For this reason, when preparing a polyester, isosorbide (ISB) is generally used as a monomer, but although ISB increases heat resistance, if ISB is contained in excess of a certain amount, the crystallinity can decrease.

[0005] Therefore, there is a demand for developing a polyester resin containing isosorbide as a monomer, but maintaining the crystallinity of the polyester and at the same time having excellent heat resistance. SUMMARY

[0006] TECHNICAL PROBLEM An object of the present application is to provide a polyester copolymer with excellent strength and heat resistance. Another object of the present application is to provide a product containing the same.

[0007] TECHNICAL SOLUTION In order to achieve this object, according to the present application, there is provided a polyester copolymer comprising: 1) a residue of a dicarboxylic acid component including terephthalic acid; and 2) a residue of a diol component including isosorbide, cyclohexanedimethanol, and an acyclic diol, wherein the copolymer comprises isosorbide residues, cyclohexanedimethanol residues, and acyclic diol residues at contents of 4 to 20 mol%, 65 to 85 mol%, and 11 to 31 mol%, respectively, based on the total moles of diol component residues, and satisfies the following mathematical formula 1: [mathematical formula 1] 30 < (X * Y) / (Z * W) < 1000 In the mathematical formula 1, X is a storage modulus (unit: MPa) of the polyester copolymer at 40℃, Y is a glass transition temperature (unit: ℃) of the polyester copolymer, Z is a melting point (unit: ℃) of the polyester copolymer, and W is a heat of fusion (unit: J / g) of the polyester copolymer.

[0008] Hereinafter, the present application will be explained in detail.

[0009] Definitions of terms The present disclosure relates to a polyester copolymer comprising: residues of a dicarboxylic acid component including terephthalic acid; and residues of a diol component including isosorbide, cyclohexanedimethanol, and acyclic diol.

[0010] As used herein, the term ‘residue’ means a specific portion or unit contained in a product of a chemical reaction and derived from the specific compound when the specific compound participates in the chemical reaction. Specifically, the ‘residue’ of the dicarboxylic acid component or the ‘residue’ of the diol component means a portion derived from the dicarboxylic acid component or the diol component in the polyester copolymer formed by esterification or polycondensation, respectively.

[0011] Dicarboxylic acid component The dicarboxylic acid component used herein means a main monomer constituting the polyester copolymer together with the diol component. In particular, the dicarboxylic acid includes terephthalic acid, and the properties of the polyester copolymer according to the present disclosure such as heat resistance, chemical resistance, weather resistance, and the like can be improved by the terephthalic acid.

[0012] In addition to terephthalic acid, the dicarboxylic acid component can include an aromatic dicarboxylic acid component, an aliphatic dicarboxylic acid component, or a mixture thereof. The dicarboxylic acid component can also include dimethyl terephthalate. In this case, it is preferable that the dicarboxylic acid component other than terephthalic acid is contained at a content of 1 to 30 wt% based on the total weight of the entire dicarboxylic acid component.

[0013] The aromatic dicarboxylic acid component can be an aromatic dicarboxylic acid or a mixture thereof having 8 to 20, preferably 8 to 14 carbon atoms. Examples of aromatic dicarboxylic acids include isophthalic acid, naphthalenedicarboxylic acids such as 2,6-naphthalenedicarboxylic acid and the like, biphenyl dicarboxylic acid, 4,4'-stilbene dicarboxylic acid, 2,5-furan dicarboxylic acid, 2,5-thiophene dicarboxylic acid and the like, but specific examples of aromatic dicarboxylic acids are not limited thereto. The aliphatic dicarboxylic acid component can be an aliphatic dicarboxylic acid or a mixture thereof having 4 to 20, preferably 4 to 12 carbon atoms. Examples of aliphatic dicarboxylic acids may include cyclohexanedicarboxylic acids such as 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid and the like, and straight-chain, branched or cyclic aliphatic dicarboxylic acids such as phthalic acid, sebacic acid, succinic acid, isodecylsuccinic acid, maleic acid, fumaric acid, adipic acid, glutaric acid, azelaic acid and the like, but specific examples of aliphatic dicarboxylic acids are not limited thereto.

[0014] Diol component The diol component used in this article refers to the main monomer that, together with the dicarboxylic acid component described above, constitutes the polyester copolymer. In particular, the diol component includes isosorbide, cyclohexanediol, and acyclic diols.

[0015] Isosorbide is used to improve the processing properties of the prepared polyester copolymer. Although the transparency and impact strength of the polyester copolymer are improved by the diol components of cyclohexanediol and acyclic diols, for better processing performance, shear flow properties should be improved and crystallization rate should be slowed, which is difficult to achieve using only cyclohexanediol and acyclic diols. Therefore, when isosorbide is included as a diol component, shear flow properties can be improved and crystallization rate can be slowed, while maintaining transparency and impact strength, thereby improving the processing properties of the prepared polyester copolymer. Preferably, isosorbide residues are included in an amount of 0.1 to 5 parts by weight based on 100 parts by weight of total diol component residues.

[0016] Cyclohexanediethanol (e.g., 1,2-cyclohexanediethanol, 1,3-cyclohexanediethanol, or 1,4-cyclohexanediethanol) is a component that contributes to the transparency and impact strength of the prepared polyester copolymer. Preferably, the cyclohexanediethanol residues are included in an amount of 30 to 70 parts by weight based on 100 parts by weight of total diol component residues.

[0017] Acyclic diols, together with cyclohexanediol, contribute to the transparency and impact strength of the prepared polyester copolymers. Acyclic diols are those whose structure does not contain rings, and preferably, they are C16-264-3 ... 2-10Alkylene glycols, more preferably ethylene glycol or diethylene glycol. Preferably, acyclic glycols are included in an amount of 5 to 25 parts by weight based on 100 parts by weight of total glycol component residues.

[0018] Furthermore, the polyester copolymers according to this disclosure comprise isosorbide residues, cyclohexanediol residues, and acyclic diol residues in amounts of 4 mol% to 20 mol%, 65 mol% to 85 mol%, and 11 mol% to 31 mol% respectively, based on the total molar number of diol component residues. When the copolymer comprises each diol component residue within the above-mentioned range, the polyester copolymers according to the present invention can exhibit excellent strength, high heat resistance, and high crystallinity.

[0019] Regarding the residue content of each diol component, the polyester copolymer according to this disclosure preferably satisfies the following mathematical formula 2: [Mathematical Formula 2] 0.04 ≤ (ISB) / (ISB+CHDM) ≤ 0.22 In mathematical formula 2, ISB represents the percentage of isosorbide residues in mol% based on the total moles of diol component residues. CHDM represents mol of cyclohexanediethanol residues based on the total molar number of diol component residues.

[0020] Mathematical Formula 2 relates to the content of isosorbide residues and cyclohexanediethanol residues, and when the ranges above are satisfied, the polyester copolymers according to this disclosure can have superior strength as well as higher heat resistance and crystallinity.

[0021] Polyester copolymer The polyester copolymers according to this disclosure can be prepared by copolymerizing the dicarboxylic acid component and the diol component described above. The copolymerization can be carried out by sequentially performing esterification and polycondensation.

[0022] Esterification is carried out in the presence of an esterification catalyst, and esterification catalysts including zinc-based compounds can be used. Specific examples of such zinc-based catalysts include zinc acetate, zinc acetate dihydrate, zinc chloride, zinc sulfate, zinc sulfide, zinc carbonate, zinc citrate, zinc gluconate, or mixtures thereof.

[0023] Esterification can be performed at 0 kg / cm 2 Up to 10.0 kg / cm 2 The esterification reaction is carried out under pressure and at temperatures ranging from 150°C to 300°C. The esterification reaction conditions can be appropriately controlled according to the specific properties of the polyester being prepared, the ratio of each component, or process conditions. Preferably, the esterification reaction can be carried out at 0 kg / cm³. 2Up to 5.0 kg / cm 2 More preferably 0.1 kg / cm 2 Up to 3.0 kg / cm 2 The pressure is 200°C to 300°C, more preferably 240°C to 280°C.

[0024] Furthermore, the esterification reaction can be carried out batchwise or continuously, and each raw material can be added separately, but preferably in the form of a slurry in which the dicarboxylic acid component and the trifunctional compound are mixed with the diol component. Alternatively, diol components that are solid at room temperature, such as isosorbide and the like, can be dissolved in water or ethylene glycol and then mixed with dicarboxylic acid components such as terephthalic acid and the like to form a slurry. Optionally, isosorbide can be melted at 60°C or higher and then mixed with dicarboxylic acid components such as terephthalic acid and the like, and other diol components to form a slurry. Additionally, water can be added to the mixed slurry to help improve its fluidity.

[0025] Furthermore, the polycondensation reaction can be carried out at a reduced pressure of 150°C to 300°C, preferably 200°C to 290°C; and 600 mmHg to 0.01 mmHg, preferably 200 mmHg to 0.05 mmHg, more preferably 100 mmHg to 0.1 mmHg. By applying reduced pressure conditions, the ethylene glycol byproducts of polycondensation can be removed from the system. Therefore, if the polycondensation reaction conditions do not fall within the range of 600 mmHg to 0.01 mmHg, the removal of byproducts may be insufficient. Moreover, if the polycondensation reaction occurs outside the temperature range of 150°C to 300°C, and if the reaction is carried out at a temperature below 150°C, the ethylene glycol byproducts of the polycondensation reaction may not be effectively removed from the system. Consequently, the intrinsic viscosity of the final reaction product may be low, and the properties of the prepared polyester copolymer may deteriorate. Furthermore, if the polycondensation reaction is carried out at a temperature above 300°C, it is more likely that the prepared polyester resin will yellow. In addition, the polycondensation reaction can be carried out for the required time until the intrinsic viscosity of the final reaction product reaches a suitable level, such as an average residence time of 1 to 24 hours.

[0026] Furthermore, the polycondensation reaction can be carried out using a polycondensation catalyst, which includes titanium-based compounds, germanium-based compounds, antimony-based compounds, aluminum-based compounds, tin-based compounds, or mixtures thereof.

[0027] Examples of titanium-based compounds include tetraethyl titanate, tripropyl titanate, tetrapropyl titanate, tetrabutyl titanate, 2-ethylhexyl titanate, octyl glycol titanate, titanate lactate, triethanolamine titanate, titanate acetylacetonate, ethyl acetoacetate titanate, isostearate titanate, titanium dioxide, and the like. Examples of germanium-based compounds include germanium dioxide, germanium tetrachloride, germanium glycol, germanium acetate, copolymers thereof, or mixtures thereof. Preferably, germanium dioxide can be used, and as such germanium dioxide, both crystalline and amorphous germanium dioxide can be used, and germanium dioxide soluble in ethylene glycol can also be used.

[0028] Furthermore, stabilizers, colorants, crystallizers, antioxidants, branching agents, etc., can be added to the product before the start of polycondensation or after the completion of polycondensation. However, the timing of introducing the additives described above is not limited to this, and they can be added at any time during the preparation steps of the polyester copolymer.

[0029] As stabilizers, phosphorus-based compounds such as phosphoric acid, trimethyl phosphate, triethyl phosphate, and the like can be used. The amount of stabilizer used (based on phosphorus content) ranges from 10 ppm to 200 ppm, depending on the weight of the final polyester copolymer. If the amount of stabilizer used is less than 10 ppm, the stabilizing effect may be insufficient, and therefore, there may be issues with yellowing of the polyester copolymer. Furthermore, if the amount of stabilizer used is greater than 200 ppm, it may not be possible to obtain the desired high degree of polymerization of the polyester copolymer.

[0030] Colorants are added to improve the color of the polyester copolymer. Anthraquinone-based compounds, pyrene-based compounds, azo-based compounds, methylene-based compounds, and the like can be used as organic compound colorants, and commercially available toners such as Polysynthren BlueRLS from Clarient, or Solvaperm Red BB from Clarient, and the like, can be used. The amount of organic compound colorant used can be controlled from 1 ppm to 50 ppm, depending on the final polyester copolymer being prepared. If the colorant content does not fall within the above range, the yellow color of the polyester copolymer may not be adequately masked, or its properties may deteriorate.

[0031] As a crystallizing agent, crystal nucleating agents, UV absorbers, polyolefin-based resins, polyamide resins, and the like can be used. As an antioxidant, hindered phenol-based antioxidants, phosphite-based antioxidants, thioether-based antioxidants, or mixtures thereof can be used. As a branching agent, conventional branching agents having three or more functional groups can be used, and for example, trimellitic anhydride, trimethylolpropane, trimellitic acid, or mixtures thereof can be used.

[0032] Furthermore, the polyester copolymers according to this disclosure can have an intrinsic viscosity of 0.60 dl / g to 1.30 dl / g, preferably 0.65 dl / g to 1.20 dl / g. Methods for measuring intrinsic viscosity will be illustrated in the examples described below.

[0033] Furthermore, the polyester copolymers according to this disclosure are characterized by satisfying the mathematical formula 1 described above. Mathematical formula 1 relates to each property of the polyester copolymers according to this disclosure, and the table illustrates that when the polyester copolymer satisfies mathematical formula 1, it exhibits excellent strength, high heat resistance, and crystallinity. In mathematical formula 1, the value of each parameter refers to a numerical value other than units. For example, when the storage modulus of the polyester copolymer according to this disclosure is 1900 MPa, X becomes 1900.

[0034] As described in the examples and comparative examples below, it can be demonstrated that there are significant differences in strength and crystallinity between cases that satisfy Mathematical Formula 1 and cases that do not satisfy Mathematical Formula 1.

[0035] Preferably, the polyester copolymer according to this disclosure has a storage modulus (X) of 1700 MPa to 2100 MPa. The method for measuring the storage modulus will be illustrated in the examples below.

[0036] Preferably, the polyester copolymer according to this disclosure has a glass transition temperature (γ) of 85°C to 115°C. Meanwhile, the method for measuring the glass transition temperature will be illustrated in the examples below.

[0037] Preferably, the polyester copolymer according to this disclosure has a melting point (Z) of 225°C to 270°C. The method for measuring the melting point will be illustrated in the examples below.

[0038] Preferably, the polyester copolymer according to this disclosure has a heat of fusion (W) of 1 J / g to 20 J / g. The method for measuring the heat of fusion will be illustrated in the examples below.

[0039] According to this disclosure, products comprising polyester copolymers are also provided.

[0040] Beneficial effects The polyester copolymers described above according to this disclosure have excellent strength and heat resistance, and therefore, a variety of containers made therefrom can be used in dishwashers and the like, and can withstand high pressures such as those in carbonated water containers. Detailed Implementation

[0041] In the following description, preferred embodiments are provided to better understand the invention. However, these embodiments are provided only for the purpose of better understanding the invention, and the scope of the invention is not limited thereto.

[0042] Example 1 Step 1) Esterification TPA (terephthalic acid; 2666.7 g), EG (ethylene glycol; 597.6 g), CHDM (1,4-cyclohexanediethanol; 1573.0 g), and ISB (isosorbide; 281.4 g) were added to a 10 L capacity reactor connected to a column and a water-cooled condenser. GeO2 (13.1 g) was added as a catalyst, phosphoric acid (8.7 g) as a stabilizer, Polysynthren Blue RLS (Clarient, 0.016 g) as a blue colorant, Solvaperm Red BB (Clarient, 0.004 g) as a red colorant, and trimellitic anhydride (0.4 g) as a branching agent.

[0043] Subsequently, nitrogen gas was added to the reactor to create a pressurized environment, wherein the pressure in the reactor was 1.0 kgf / cm² higher than atmospheric pressure. 2 Furthermore, the reactor temperature was raised to 220°C over 90 minutes and maintained at 220°C for 2 hours, then raised to 260°C over another 2 hours. The mixture in the reactor was then visually inspected while the reactor temperature was maintained at 260°C for esterification for 245 minutes, until the mixture became transparent. During this process, byproducts were discharged through a column and condenser. After esterification was complete, the nitrogen gas inside the pressurized reactor was vented to reduce the reactor pressure to atmospheric pressure, and the mixture was then transferred to a 7L capacity reactor capable of vacuum reaction.

[0044] Step 2) Polycondensation The pressure in a 7 L capacity reactor was reduced from atmospheric pressure to 5 Torr (absolute pressure: 5 mmHg) over 30 minutes, while simultaneously raising the reactor temperature to 265°C over 1 hour. Polycondensation was carried out while maintaining the reactor pressure at 1 Torr (absolute pressure: 1 mmHg) or less. At the start of polycondensation, the stirring speed was set to high, but could be appropriately controlled if, as polycondensation progressed, the stirring force decreased due to increased reactant viscosity or the reactant temperature rose above a predetermined level. Polycondensation continued until the intrinsic viscosity (IV) of the mixture (molten material) in the reactor reached 0.71 dl / g. If the intrinsic viscosity of the mixture in the reactor reached the desired level, the mixture was discharged from the reactor and formed into a filament, which was then solidified with a coolant and granulated to achieve an average weight of approximately 12 to 14 mg.

[0045] The granules were placed at 150°C for 1 hour to crystallize, and then added to a solid-state polymerization reactor with a capacity of 20 L. Nitrogen gas was then introduced into the reactor at a rate of 50 L / min. The reactor temperature was increased from room temperature to 140°C at a rate of 40°C / hour and maintained at 140°C for 3 hours, and then increased to 190°C at a rate of 40°C / hour and maintained at 190°C. Solid-state polymerization was carried out until the intrinsic viscosity (IV) of the granules in the reactor became 0.80 dl / g, thereby preparing a polyester copolymer.

[0046] Example 2 Step 1) Esterification TPA (2374.1 g), EG (150.7 g), CHDM (1482.8 g), and ISB (751.7 g) were added to a 10 L capacity reactor connected to a column and a water-cooled condenser. GeO2 (13.1 g) was added as a catalyst, phosphoric acid (8.7 g) as a stabilizer, Polysynthren Blue RLS (Clarient, 0.019 g) as a blue colorant, Solvaperm Red BB (Clarient, 0.004 g) as a red colorant, and high-density polyethylene (SKGeO centric Co., Ltd. YUZEX 2600S; 0.0038 g) as a crystallizer.

[0047] Subsequently, nitrogen gas was added to the reactor to create a pressurized environment, wherein the pressure in the reactor was 2.0 kgf / cm² higher than atmospheric pressure. 2Furthermore, the reactor temperature was raised to 220°C over 90 minutes and maintained at 220°C for 2 hours, then raised to 280°C after another 2 hours. The mixture in the reactor was then visually inspected while the reactor temperature was maintained at 280°C for esterification for 245 minutes, until the mixture became transparent. During this process, byproducts were discharged through a column and condenser. After esterification was complete, the nitrogen gas inside the pressurized reactor was vented to reduce the reactor pressure to atmospheric pressure, and the mixture was then transferred to a 7L capacity reactor capable of vacuum reaction.

[0048] Step 2) Polycondensation The pressure in a 7 L capacity reactor was reduced from atmospheric pressure to 5 Torr (absolute pressure: 5 mmHg) over 30 minutes, while the reactor temperature was simultaneously increased to 290°C over 1 hour. Polycondensation was carried out while maintaining the reactor pressure at 1 Torr (absolute pressure: 1 mmHg) or less. At the start of polycondensation, the stirring speed was set to high, but could be appropriately controlled if, as polycondensation progressed, the viscosity of the reactants increased, the stirring force decreased, or the temperature of the reactants rose above a predetermined level. Polycondensation continued until the intrinsic viscosity (IV) of the mixture (molten material) in the reactor became 0.65 dl / g. If the intrinsic viscosity of the mixture in the reactor reached the desired level, the mixture was discharged from the reactor and formed into filaments, which were then solidified with a coolant and granulated to an average weight of approximately 12 mg to 14 mg, thus preparing the polyester copolymer.

[0049] Example 3 Step 1) Esterification TPA (2375.9 g), EG (248.5 g), CHDM (1690.0 g), and ISB (417.9 g) were added to a 10 L capacity reactor connected to a column and a water-cooled condenser. GeO2 (13.1 g) was added as a catalyst, phosphoric acid (8.7 g) as a stabilizer, Polysynthren Blue RLS (Clarient, 0.019 g) as a blue colorant, and Solvaperm Red BB (Clarient, 0.004 g) as a red colorant.

[0050] Subsequently, nitrogen gas was added to the reactor to create a pressurized environment, wherein the pressure in the reactor was 1.0 kgf / cm² higher than atmospheric pressure. 2Furthermore, the reactor temperature was raised to 220°C over 90 minutes and maintained at 220°C for 2 hours, then raised to 270°C over another 2 hours. The mixture in the reactor was then visually inspected while the reactor temperature was maintained at 270°C for esterification for 245 minutes, until the mixture became transparent. During this process, byproducts were discharged through a column and condenser. After esterification was complete, the nitrogen gas inside the pressurized reactor was vented to reduce the reactor pressure to atmospheric pressure, and the mixture was then transferred to a 7L capacity reactor capable of vacuum reaction.

[0051] Step 2) Polycondensation The pressure in a 7 L capacity reactor was reduced from atmospheric pressure to 5 Torr (absolute pressure: 5 mmHg) over 30 minutes, while simultaneously raising the reactor temperature to 290°C over 1 hour. Polycondensation was carried out while maintaining the reactor pressure at 1 Torr (absolute pressure: 1 mmHg) or less. At the start of polycondensation, the stirring speed was set to rapid, but could be appropriately controlled if, as polycondensation progressed, the stirring force decreased due to increased reactant viscosity or if the reactant temperature exceeded a predetermined level. Polycondensation continued until the intrinsic viscosity (IV) of the mixture (molten material) in the reactor reached 0.74 dl / g. If the intrinsic viscosity of the mixture in the reactor reached the desired level, the mixture was discharged from the reactor and formed into a filament, which was then solidified with a coolant and granulated to achieve an average weight of approximately 12 mg to 14 mg.

[0052] The granules were placed at 150°C for 1 hour to crystallize, and then added to a solid-state polymerization reactor with a capacity of 20 L. Nitrogen gas was then introduced into the reactor at a rate of 50 L / min. The reactor temperature was increased from room temperature to 140°C at a rate of 40°C / hour and maintained at 140°C for 3 hours, and then increased to 200°C at a rate of 40°C / hour and maintained at 200°C. Solid-state polymerization was carried out until the intrinsic viscosity (IV) of the granules in the reactor became 0.95 dl / g, thereby preparing a polyester copolymer.

[0053] Example 4 Step 1) Esterification TPA (3127.4 g), EG (257.0 g), CHDM (2360.2 g), and ISB (302.6 g) were added to a 10 L capacity reactor connected to a column and a water-cooled condenser. GeO2 (16.4 g) was added as a catalyst, phosphoric acid (10.9 g) as a stabilizer, Polysynthren Blue RLS (Clarient, 0.020 g) as a blue colorant, Solvaperm Red BB (Clarient, 0.005 g) as a red colorant, and Irganox 1076 (0.5 g) as an antioxidant.

[0054] Subsequently, nitrogen gas was added to the reactor to create a pressurized environment, wherein the pressure in the reactor was 1.0 kgf / cm² higher than atmospheric pressure. 2 Furthermore, the reactor temperature was raised to 220°C over 90 minutes and maintained at 220°C for 2 hours, then raised to 240°C after another 2 hours. The mixture in the reactor was then visually inspected while the reactor temperature was maintained at 240°C for esterification for 245 minutes, until the mixture became transparent. During this process, byproducts were discharged through a column and condenser. After esterification was complete, the nitrogen gas inside the pressurized reactor was vented to reduce the reactor pressure to atmospheric pressure, and the mixture was then transferred to a 7L capacity reactor capable of vacuum reaction.

[0055] Step 2) Polycondensation The pressure in a 7 L capacity reactor was reduced from atmospheric pressure to 5 Torr (absolute pressure: 5 mmHg) over 30 minutes, while simultaneously raising the reactor temperature to 290°C over 1 hour. Polycondensation was carried out while maintaining the reactor pressure at 1 Torr (absolute pressure: 1 mmHg) or less. At the start of polycondensation, the stirring speed was set to rapid, but could be appropriately controlled if, as polycondensation progressed, the stirring force decreased due to increased reactant viscosity or if the reactant temperature exceeded a predetermined level. Polycondensation continued until the intrinsic viscosity (IV) of the mixture (molten material) in the reactor reached 0.68 dl / g. If the intrinsic viscosity of the mixture in the reactor reached the desired level, the mixture was discharged from the reactor and formed into a filament, which was then solidified with a coolant and granulated to achieve an average weight of approximately 12 to 14 mg.

[0056] The granules were placed at 150°C for 1 hour to crystallize, and then added to a solid-state polymerization reactor with a capacity of 20 L. Nitrogen gas was then introduced into the reactor at a rate of 50 L / min. The reactor temperature was increased from room temperature to 140°C at a rate of 40°C / hour and maintained at 140°C for 3 hours, and then increased to 220°C at a rate of 40°C / hour and maintained at 220°C. Solid-state polymerization was carried out until the intrinsic viscosity (IV) of the granules in the reactor became 1.0 dl / g, thereby preparing a polyester copolymer.

[0057] Example 5 Step 1) Esterification TPA (2548.0 g), EG (304.5 g), CHDM (1635.6 g), and ISB (425.8 g) were added to a 10 L capacity reactor connected to a column and a water-cooled condenser. GeO2 (13.1 g) was added as a catalyst, phosphoric acid (8.7 g) as a stabilizer, Polysynthren Blue RLS (Clarient, 0.020 g) as a blue colorant, Solvaperm Red BB (Clarient, 0.008 g) as a red colorant, and Irganox 1076 (0.4 g) as an antioxidant.

[0058] Subsequently, nitrogen gas was added to the reactor to create a pressurized environment, wherein the pressure in the reactor was 1.0 kgf / cm² higher than atmospheric pressure. 2 Furthermore, the reactor temperature was raised to 220°C over 90 minutes and maintained at 220°C for 2 hours, then raised to 255°C over another 2 hours. The mixture in the reactor was then visually inspected while the reactor temperature was maintained at 255°C for esterification for 245 minutes, until the mixture became transparent. During this process, byproducts were discharged through a column and condenser. After esterification was complete, the nitrogen gas inside the pressurized reactor was vented to reduce the reactor pressure to atmospheric pressure, and the mixture was then transferred to a 7L capacity reactor capable of vacuum reaction.

[0059] Step 2) Polycondensation The pressure in a 7 L capacity reactor was reduced from atmospheric pressure to 5 Torr (absolute pressure: 5 mmHg) over 30 minutes, while simultaneously raising the reactor temperature to 280°C over 1 hour. Polycondensation was carried out while maintaining the reactor pressure at 1 Torr (absolute pressure: 1 mmHg) or less. At the start of polycondensation, the stirring speed was set to rapid, but could be appropriately controlled if, as polycondensation progressed, the stirring force decreased due to increased reactant viscosity or if the reactant temperature exceeded a predetermined level. Polycondensation continued until the intrinsic viscosity (IV) of the mixture (molten material) in the reactor reached 0.70 dl / g. If the intrinsic viscosity of the mixture in the reactor reached the desired level, the mixture was discharged from the reactor and formed into a filament, which was then solidified with a coolant and granulated to achieve an average weight of approximately 12 mg to 14 mg.

[0060] The granules were placed at 150°C for 1 hour to crystallize, and then added to a solid-state polymerization reactor with a capacity of 20 L. Nitrogen gas was then introduced into the reactor at a rate of 50 L / min. The reactor temperature was increased from room temperature to 140°C at a rate of 40°C / hour and maintained at 140°C for 3 hours, and then increased to 220°C at a rate of 40°C / hour and maintained at 220°C. Solid-state polymerization was carried out until the intrinsic viscosity (IV) of the granules in the reactor became 1.2 dl / g, thereby preparing a polyester copolymer.

[0061] Example 6 Step 1) Esterification TPA (2382.2 g), EG (115.7 g), CHDM (1508.5 g), and ISB (398.1 g) were added to a 10 L capacity reactor connected to a column and a water-cooled condenser. GeO2 (12.4 g) was added as a catalyst, phosphoric acid (8.2 g) as a stabilizer, Polysynthren Blue RLS (Clarient, 0.027 g) as a blue colorant, Solvaperm Red BB (Clarient, 0.008 g) as a red colorant, and Irganox 1076 (0.38 g) as an antioxidant.

[0062] Subsequently, nitrogen gas was added to the reactor to create a pressurized environment, wherein the pressure in the reactor was 0.5 kgf / cm² higher than atmospheric pressure. 2Furthermore, the reactor temperature was raised to 220°C over 90 minutes and maintained at 220°C for 2 hours, then raised to 250°C over another 2 hours. The mixture in the reactor was then visually inspected while the reactor temperature was maintained at 250°C for esterification for 245 minutes, until the mixture became transparent. During this process, byproducts were discharged through a column and condenser. After esterification was complete, the nitrogen gas inside the pressurized reactor was vented to reduce the reactor pressure to atmospheric pressure, and the mixture was then transferred to a 7L capacity reactor capable of vacuum reaction.

[0063] Step 2) Polycondensation The pressure in a 7 L capacity reactor was reduced from atmospheric pressure to 5 Torr (absolute pressure: 5 mmHg) over 30 minutes, while simultaneously raising the reactor temperature to 290°C over 1 hour. Polycondensation was carried out while maintaining the reactor pressure at 1 Torr (absolute pressure: 1 mmHg) or less. At the start of polycondensation, the stirring speed was set to rapid, but could be appropriately controlled if, as polycondensation progressed, the stirring force decreased due to increased reactant viscosity or the reactant temperature exceeded a predetermined level. Polycondensation continued until the intrinsic viscosity (IV) of the mixture (molten material) in the reactor reached 0.72 dl / g. If the intrinsic viscosity of the mixture in the reactor reached the desired level, the mixture was discharged from the reactor and formed into a filament, which was then solidified with a coolant and granulated to achieve an average weight of approximately 12 to 14 mg.

[0064] The granules were placed at 150°C for 1 hour to crystallize, and then added to a solid-state polymerization reactor with a capacity of 20 L. Nitrogen gas was then introduced into the reactor at a rate of 50 L / min. The reactor temperature was increased from room temperature to 140°C at a rate of 40°C / hour and maintained at 140°C for 3 hours, and then increased to 205°C at a rate of 40°C / hour and maintained at 205°C. Solid-state polymerization was carried out until the intrinsic viscosity (IV) of the granules in the reactor became 1.1 dl / g, thereby preparing a polyester copolymer.

[0065] Example 7 Step 1) Esterification DMT (dimethyl terephthalate; 3126.6 g), EG (1229.1 g), CHDM (1740.6 g), and ISB (753.0 g) were added to a 10 L capacity reactor connected to a column and a water-cooled condenser. GeO2 (13.8 g) was added as a catalyst, phosphoric acid (9.1 g) as a stabilizer, Polysynthren Blue RLS (Clarient, 0.021 g) as a blue colorant, and Solvaperm Red BB (Clarient, 0.008 g) as a red colorant.

[0066] Nitrogen gas was then added to the reactor to bring the pressure to atmospheric pressure. The reactor temperature was then raised to 220°C over 90 minutes and maintained at 220°C for 2 hours, followed by a further increase to 240°C over 2 hours. The mixture in the reactor was then visually inspected while the temperature was maintained at 240°C for esterification for 245 minutes, until the mixture became transparent. During this process, byproducts were discharged through a column and condenser. After esterification, the mixture was transferred to a 7 L capacity reactor capable of vacuum reaction.

[0067] Step 2) Polycondensation The pressure in a 7 L capacity reactor was reduced from atmospheric pressure to 5 Torr (absolute pressure: 5 mmHg) over 30 minutes, while simultaneously raising the reactor temperature to 270°C over 1 hour. Polycondensation was carried out while maintaining the reactor pressure at 1 Torr (absolute pressure: 1 mmHg) or less. At the start of polycondensation, the stirring speed was set to high, but could be appropriately controlled if, as polycondensation progressed, the viscosity of the reactants increased, the stirring force decreased, or the temperature of the reactants rose above a predetermined level. Polycondensation continued until the intrinsic viscosity (IV) of the mixture (molten material) in the reactor became 0.70 dl / g. If the intrinsic viscosity of the mixture in the reactor reached the desired level, the mixture was discharged from the reactor and formed into a filament, which was then solidified with a coolant and granulated to achieve an average weight of approximately 12 mg to 14 mg.

[0068] The granules were placed at 150°C for 1 hour to crystallize, and then added to a solid-state polymerization reactor with a capacity of 20 L. Nitrogen gas was then introduced into the reactor at a rate of 50 L / min. The reactor temperature was increased from room temperature to 140°C at a rate of 40°C / hour and maintained at 140°C for 3 hours, and then increased to 200°C at a rate of 40°C / hour and maintained at 200°C. Solid-state polymerization was carried out until the intrinsic viscosity (IV) of the granules in the reactor became 1.0 dl / g, thereby preparing a polyester copolymer.

[0069] Example 8 Step 1) Esterification TPA (2420.6 g), IPA (isophthalic acid; 127.4 g), EG (304.5 g), CHDM (1635.6 g), and ISB (425.8 g) were added to a 10 L capacity reactor connected to a column and a water-cooled condenser. GeO2 (13.1 g) was added as a catalyst, phosphoric acid (8.7 g) as a stabilizer, Polysynthren BlueRLS (Clarient, 0.020 g) as a blue colorant, and Solvaperm Red BB (Clarient, 0.008 g) as a red colorant.

[0070] Subsequently, nitrogen gas was added to the reactor to create a pressurized environment, wherein the pressure in the reactor was 1.0 kgf / cm² higher than atmospheric pressure. 2 Furthermore, the reactor temperature was raised to 220°C over 90 minutes and maintained at 220°C for 2 hours, then raised to 260°C over another 2 hours. The mixture in the reactor was then visually inspected while the reactor temperature was maintained at 260°C for esterification for 245 minutes, until the mixture became transparent. During this process, byproducts were discharged through a column and condenser. After esterification was complete, the nitrogen gas inside the pressurized reactor was vented to reduce the reactor pressure to atmospheric pressure, and the mixture was then transferred to a 7L capacity reactor capable of vacuum reaction.

[0071] Step 2) Polycondensation The pressure in a 7 L capacity reactor was reduced from atmospheric pressure to 5 Torr (absolute pressure: 5 mmHg) over 30 minutes, while simultaneously raising the reactor temperature to 285°C over 1 hour. Polycondensation was carried out while maintaining the reactor pressure at 1 Torr (absolute pressure: 1 mmHg) or less. At the start of polycondensation, the stirring speed was set to rapid, but could be appropriately controlled if, as polycondensation progressed, the stirring force decreased due to increased reactant viscosity or the reactant temperature rose above a predetermined level. Polycondensation continued until the intrinsic viscosity (IV) of the mixture (molten material) in the reactor reached 0.70 dl / g. If the intrinsic viscosity of the mixture in the reactor reached the desired level, the mixture was discharged from the reactor and formed into a filament, which was then solidified with a coolant and granulated to achieve an average weight of approximately 12 mg to 14 mg.

[0072] The granules were placed at 150°C for 1 hour to crystallize, and then added to a solid-state polymerization reactor with a capacity of 20 L. Nitrogen gas was then introduced into the reactor at a rate of 50 L / min. The reactor temperature was increased from room temperature to 140°C at a rate of 40°C / hour and maintained at 140°C for 3 hours, and then increased to 200°C at a rate of 40°C / hour and maintained at 200°C. Solid-state polymerization was carried out until the intrinsic viscosity (IV) of the granules in the reactor became 1.2 dl / g, thereby preparing a polyester copolymer.

[0073] Comparative Example 1 Step 1) Esterification TPA (3417.6 g), EG (1314.8 g), and ISB (661.3 g) were added to a 10 L capacity reactor connected to a column and a water-cooled condenser. GeO2 (5.5 g) was added as a catalyst, phosphoric acid (3.0 g) as a stabilizer, Polysynthren Blue RLS (Clarient, 0.013 g) as a blue colorant, and Solvaperm Red BB (Clarient, 0.004 g) as a red colorant.

[0074] Subsequently, nitrogen gas was added to the reactor to create a pressurized environment, wherein the pressure in the reactor was 0.5 kgf / cm² higher than atmospheric pressure. 2Furthermore, the reactor temperature was raised to 220°C over 90 minutes and maintained at 220°C for 2 hours, then raised to 260°C over another 2 hours. The mixture in the reactor was then visually inspected while the reactor temperature was maintained at 260°C for esterification for 245 minutes, until the mixture became transparent. During this process, byproducts were discharged through a column and condenser. After esterification was complete, the nitrogen gas inside the pressurized reactor was vented to reduce the reactor pressure to atmospheric pressure, and the mixture was then transferred to a 7L capacity reactor capable of vacuum reaction.

[0075] Step 2) Polycondensation The pressure in a 7 L capacity reactor was reduced from atmospheric pressure to 5 Torr (absolute pressure: 5 mmHg) over 30 minutes, while simultaneously raising the reactor temperature to 275°C over 1 hour. Polycondensation was carried out while maintaining the reactor pressure at 1 Torr (absolute pressure: 1 mmHg) or less. At the start of polycondensation, the stirring speed was set to high, but could be appropriately controlled if, as polycondensation progressed, the viscosity of the reactants increased, the stirring force decreased, or the temperature of the reactants rose above a predetermined level. Polycondensation continued until the intrinsic viscosity (IV) of the mixture (molten material) in the reactor became 0.75 dl / g. If the intrinsic viscosity of the mixture in the reactor reached the desired level, the mixture was discharged from the reactor and formed into a filament, which was then solidified with a coolant and subsequently granulated to an average weight of approximately 12 mg to 14 mg, thus preparing the polyester copolymer.

[0076] Comparative Example 2 Step 1) Esterification TPA (2657.1 g), EG (793.9 g), CHDM (1498.2 g), and ISB (701.1 g) were added to a 10 L capacity reactor connected to a column and a water-cooled condenser. GeO2 (13.1 g) was added as a catalyst, phosphoric acid (8.7 g) as a stabilizer, Polysynthren Blue RLS (Clarient, 0.012 g) as a blue colorant, and Solvaperm Red BB (Clarient, 0.004 g) as a red colorant.

[0077] Subsequently, nitrogen gas was added to the reactor to create a pressurized environment, wherein the pressure in the reactor was 1.0 kgf / cm² higher than atmospheric pressure. 2Furthermore, the reactor temperature was raised to 220°C over 90 minutes and maintained at 220°C for 2 hours, then raised to 255°C over another 2 hours. The mixture in the reactor was then visually inspected while the reactor temperature was maintained at 255°C for esterification for 245 minutes, until the mixture became transparent. During this process, byproducts were discharged through a column and condenser. After esterification was complete, the nitrogen gas inside the pressurized reactor was vented to reduce the reactor pressure to atmospheric pressure, and the mixture was then transferred to a 7L capacity reactor capable of vacuum reaction.

[0078] Step 2) Polycondensation The pressure in a 7 L capacity reactor was reduced from atmospheric pressure to 5 Torr (absolute pressure: 5 mmHg) over 30 minutes, while simultaneously raising the reactor temperature to 285°C over 1 hour. Polycondensation was carried out while maintaining the reactor pressure at 1 Torr (absolute pressure: 1 mmHg) or less. At the start of polycondensation, the stirring speed was set to high, but could be appropriately controlled if, as polycondensation progressed, the viscosity of the reactants increased, the stirring force decreased, or the temperature of the reactants rose above a predetermined level. Polycondensation continued until the intrinsic viscosity (IV) of the mixture (molten material) in the reactor became 0.65 dl / g. If the intrinsic viscosity of the mixture in the reactor reached the desired level, the mixture was discharged from the reactor and formed into a filament, which was then solidified with a coolant and subsequently granulated to an average weight of approximately 12 mg to 14 mg, thus preparing the polyester copolymer.

[0079] Comparative Example 3 Step 1) Esterification TPA (2209.6 g), CHDM (1859.2 g), and ISB (252.6 g) were added to a 10 L capacity reactor connected to a column and a water-cooled condenser. GeO2 (12.8 g) was added as a catalyst, phosphoric acid (8.5 g) as a stabilizer, Polysynthren Blue RLS (Clarient, 0.012 g) as a blue colorant, and Solvaperm Red BB (Clarient, 0.004 g) as a red colorant.

[0080] Subsequently, nitrogen gas was added to the reactor to create a pressurized environment, wherein the pressure in the reactor was 2.0 kgf / cm² higher than atmospheric pressure. 2Furthermore, the reactor temperature was raised to 220°C over 90 minutes and maintained at 220°C for 2 hours, then raised to 250°C over another 2 hours. The mixture in the reactor was then visually inspected while the reactor temperature was maintained at 250°C for esterification for 245 minutes, until the mixture became transparent. During this process, byproducts were discharged through a column and condenser. After esterification was complete, the nitrogen gas inside the pressurized reactor was vented to reduce the reactor pressure to atmospheric pressure, and the mixture was then transferred to a 7L capacity reactor capable of vacuum reaction.

[0081] Step 2) Polycondensation The pressure in a 7 L capacity reactor was reduced from atmospheric pressure to 5 Torr (absolute pressure: 5 mmHg) over 30 minutes, while simultaneously raising the reactor temperature to 270°C over 1 hour. Polycondensation was carried out while maintaining the reactor pressure at 1 Torr (absolute pressure: 1 mmHg) or less. At the start of polycondensation, the stirring speed was set to high, but could be appropriately controlled if, as polycondensation progressed, the viscosity of the reactants increased, the stirring force decreased, or the temperature of the reactants rose above a predetermined level. Polycondensation continued until the intrinsic viscosity (IV) of the mixture (molten material) in the reactor became 0.70 dl / g. If the intrinsic viscosity of the mixture in the reactor reached the desired level, the mixture was discharged from the reactor and formed into a filament, which was then solidified with a coolant and granulated to achieve an average weight of approximately 12 mg to 14 mg.

[0082] The granules were placed at 150°C for 1 hour to crystallize, and then added to a solid-state polymerization reactor with a capacity of 20 L. Nitrogen gas was then introduced into the reactor at a rate of 50 L / min. The reactor temperature was increased from room temperature to 140°C at a rate of 40°C / hour and maintained at 140°C for 3 hours, and then increased to 200°C at a rate of 40°C / hour and maintained at 200°C. Solid-state polymerization was carried out until the intrinsic viscosity (IV) of the granules in the reactor became 0.95 dl / g, thereby preparing a polyester copolymer.

[0083] Comparative Example 4 Step 1) Esterification TPA (2377.9 g), CHDM (1835.9 g), and ISB (648.3 g) were added to a 10 L capacity reactor connected to a column and a water-cooled condenser. GeO2 (13.8 g) was added as a catalyst, phosphoric acid (9.1 g) as a stabilizer, Polysynthren Blue RLS (Clarient, 0.021 g) as a blue colorant, Solvaperm Red BB (Clarient, 0.004 g) as a red colorant, and Irganox 1076 (0.42 g) as an antioxidant.

[0084] Subsequently, nitrogen gas was added to the reactor to create a pressurized environment, wherein the pressure in the reactor was 1.0 kgf / cm² higher than atmospheric pressure. 2 Furthermore, the reactor temperature was raised to 220°C over 90 minutes and maintained at 220°C for 2 hours, then raised to 265°C over another 2 hours. The mixture in the reactor was then visually inspected while the reactor temperature was maintained at 265°C for esterification for 245 minutes, until the mixture became transparent. During this process, byproducts were discharged through a column and condenser. After esterification was complete, the nitrogen gas inside the pressurized reactor was vented to reduce the reactor pressure to atmospheric pressure, and the mixture was then transferred to a 7L capacity reactor capable of vacuum reaction.

[0085] Step 2) Polycondensation The pressure in a 7 L capacity reactor was reduced from atmospheric pressure to 5 Torr (absolute pressure: 5 mmHg) over 30 minutes, while simultaneously raising the reactor temperature to 275°C over 1 hour. Polycondensation was carried out while maintaining the reactor pressure at 1 Torr (absolute pressure: 1 mmHg) or less. At the start of polycondensation, the stirring speed was set to high, but could be appropriately controlled if, as polycondensation progressed, the stirring force decreased due to increased reactant viscosity or if the reactant temperature exceeded a predetermined level. Polycondensation continued until the intrinsic viscosity (IV) of the mixture (molten material) in the reactor reached 0.68 dl / g. If the intrinsic viscosity of the mixture in the reactor reached the desired level, the mixture was discharged from the reactor and formed into a filament, which was then solidified with a coolant and granulated to achieve an average weight of approximately 12 to 14 mg.

[0086] The granules were placed at 150°C for 1 hour to crystallize, and then added to a solid-state polymerization reactor with a capacity of 20 L. Nitrogen gas was then introduced into the reactor at a rate of 50 L / min. The reactor temperature was increased from room temperature to 140°C at a rate of 40°C / hour and maintained at 140°C for 3 hours, and then increased to 200°C at a rate of 40°C / hour and maintained at 200°C. Solid-state polymerization was carried out until the intrinsic viscosity (IV) of the granules in the reactor became 1.0 dl / g, thereby preparing a polyester copolymer.

[0087] Comparative Example 5 Step 1) Esterification TPA (2234.8 g), CHDM (1512.1 g), and ISB (825.5 g) were added to a 10 L capacity reactor connected to a column and a water-cooled condenser. GeO2 (12.9 g) was added as a catalyst, phosphoric acid (8.6 g) as a stabilizer, Polysynthren Blue RLS (Clarient, 0.020 g) as a blue colorant, Solvaperm Red BB (Clarient, 0.004 g) as a red colorant, and high-density polyethylene (SK GeOcentric YUZEX 2600S; 0.3950 g) as a crystallizer.

[0088] Subsequently, nitrogen gas was added to the reactor to create a pressurized environment, wherein the pressure in the reactor was 0.5 kgf / cm² higher than atmospheric pressure. 2 Furthermore, the reactor temperature was raised to 220°C over 90 minutes and maintained at 220°C for 2 hours, then raised to 260°C over another 2 hours. The mixture in the reactor was then visually inspected while the reactor temperature was maintained at 260°C for esterification for 245 minutes, until the mixture became transparent. During this process, byproducts were discharged through a column and condenser. After esterification was complete, the nitrogen gas inside the pressurized reactor was vented to reduce the reactor pressure to atmospheric pressure, and the mixture was then transferred to a 7L capacity reactor capable of vacuum reaction.

[0089] Step 2) Polycondensation The pressure in a 7 L capacity reactor was reduced from atmospheric pressure to 5 Torr (absolute pressure: 5 mmHg) over 30 minutes, while simultaneously raising the reactor temperature to 275°C over 1 hour. Polycondensation was carried out while maintaining the reactor pressure at 1 Torr (absolute pressure: 1 mmHg) or less. At the start of polycondensation, the stirring speed was set to rapid, but could be appropriately controlled if, as polycondensation progressed, the stirring force decreased due to increased reactant viscosity or if the reactant temperature exceeded a predetermined level. Polycondensation continued until the intrinsic viscosity (IV) of the mixture (molten material) in the reactor reached 0.70 dl / g. If the intrinsic viscosity of the mixture in the reactor reached the desired level, the mixture was discharged from the reactor and formed into a filament, which was then solidified with a coolant and granulated to achieve an average weight of approximately 12 to 14 mg.

[0090] The granules were placed at 150°C for 1 hour to crystallize, and then added to a solid-state polymerization reactor with a capacity of 20 L. Nitrogen gas was then introduced into the reactor at a rate of 50 L / min. The reactor temperature was increased from room temperature to 140°C at a rate of 40°C / hour and maintained at 140°C for 3 hours, and then increased to 200°C at a rate of 40°C / hour and maintained at 200°C. Solid-state polymerization was carried out until the intrinsic viscosity (IV) of the granules in the reactor became 0.98 dl / g, thereby preparing a polyester copolymer.

[0091] Comparative Example 6 Step 1) Esterification TPA (2612.0 g), EG (595.1 g), CHDM (1404.8 g), and ISB (160.8 g) were added to a 10 L capacity reactor connected to a column and a water-cooled condenser. GeO2 (12.4 g) was added as a catalyst, phosphoric acid (8.2 g) as a stabilizer, Polysynthren Blue RLS (Clarient, 0.011 g) as a blue colorant, Solvaperm Red BB (Clarient, 0.004 g) as a red colorant, and trimellitic anhydride (0.38 g) as a branching agent.

[0092] Subsequently, nitrogen gas was added to the reactor to create a pressurized environment, wherein the pressure in the reactor was 1.0 kgf / cm² higher than atmospheric pressure. 2Furthermore, the reactor temperature was raised to 220°C over 90 minutes and maintained at 220°C for 2 hours, then raised to 265°C over another 2 hours. The mixture in the reactor was then visually inspected while the reactor temperature was maintained at 265°C for esterification for 245 minutes, until the mixture became transparent. During this process, byproducts were discharged through a column and condenser. After esterification was complete, the nitrogen gas inside the pressurized reactor was vented to reduce the reactor pressure to atmospheric pressure, and the mixture was then transferred to a 7L capacity reactor capable of vacuum reaction.

[0093] Step 2) Polycondensation The pressure in a 7 L capacity reactor was reduced from atmospheric pressure to 5 Torr (absolute pressure: 5 mmHg) over 30 minutes, while the reactor temperature was simultaneously increased to 280°C over 1 hour. Polycondensation was carried out while maintaining the reactor pressure at 1 Torr (absolute pressure: 1 mmHg) or less. At the start of polycondensation, the stirring speed was set to high, but could be appropriately controlled if, as polycondensation progressed, the viscosity of the reactants increased, the stirring force decreased, or the temperature of the reactants rose above a predetermined level. Polycondensation continued until the intrinsic viscosity (IV) of the mixture (molten material) in the reactor reached 0.70 dl / g. If the intrinsic viscosity of the mixture in the reactor reached the desired level, the mixture was discharged from the reactor and formed into a filament, which was then solidified with a coolant and granulated to an average weight of approximately 12 mg to 14 mg, thus preparing the polyester copolymer.

[0094] Comparative Example 7 Step 1) Esterification TPA (2576.1 g), EG (327.1 g), CHDM (1430.2 g), and ISB (951.6 g) were added to a 10 L capacity reactor connected to a column and a water-cooled condenser. GeO2 (13.4 g) was added as a catalyst, phosphoric acid (8.9 g) as a stabilizer, Polysynthren Blue RLS (Clarient, 0.021 g) as a blue colorant, Solvaperm Red BB (Clarient, 0.004 g) as a red colorant, and high-density polyethylene (SKGeO centric YUZEX 2600S; 0.0041 g) as a crystallizer.

[0095] Subsequently, nitrogen gas was added to the reactor to create a pressurized environment, wherein the pressure in the reactor was 0.5 kgf / cm² higher than atmospheric pressure. 2Furthermore, the reactor temperature was raised to 220°C over 90 minutes and maintained at 220°C for 2 hours, then raised to 270°C over another 2 hours. The mixture in the reactor was then visually inspected while the reactor temperature was maintained at 270°C for esterification for 245 minutes, until the mixture became transparent. During this process, byproducts were discharged through a column and condenser. After esterification was complete, the nitrogen gas inside the pressurized reactor was vented to reduce the reactor pressure to atmospheric pressure, and the mixture was then transferred to a 7L capacity reactor capable of vacuum reaction.

[0096] Step 2) Polycondensation The pressure in a 7 L capacity reactor was reduced from atmospheric pressure to 5 Torr (absolute pressure: 5 mmHg) over 30 minutes, while the reactor temperature was simultaneously increased to 275°C over 1 hour. Polycondensation was carried out while maintaining the reactor pressure at 1 Torr (absolute pressure: 1 mmHg) or less. At the start of polycondensation, the stirring speed was set to high, but could be appropriately controlled if, as polycondensation progressed, the stirring force decreased due to increased reactant viscosity or the reactant temperature exceeded a predetermined level. Polycondensation continued until the intrinsic viscosity (IV) of the mixture (molten material) in the reactor reached 0.67 dl / g. If the intrinsic viscosity of the mixture in the reactor reached the desired level, the mixture was discharged from the reactor and formed into a filament, which was then solidified with a coolant and granulated to an average weight of approximately 12 mg to 14 mg, thus preparing the polyester copolymer.

[0097] Comparative Example 8 Step 1) Esterification TPA (2598.8 g), EG (223.2 g), CHDM (1668.3 g), and ISB (182.9 g) were added to a 10 L capacity reactor connected to a column and a water-cooled condenser. GeO2 (13.1 g) was added as a catalyst, phosphoric acid (8.7 g) as a stabilizer, Polysynthren Blue RLS (Clarient, 0.024 g) as a blue colorant, and Solvaperm Red BB (Clarient, 0.004 g) as a red colorant.

[0098] Subsequently, nitrogen gas was added to the reactor to create a pressurized environment, wherein the pressure in the reactor was 1.0 kgf / cm² higher than atmospheric pressure. 2Furthermore, the reactor temperature was raised to 220°C over 90 minutes and maintained at 220°C for 2 hours, then raised to 255°C over another 2 hours. The mixture in the reactor was then visually inspected while the reactor temperature was maintained at 255°C for esterification for 245 minutes, until the mixture became transparent. During this process, byproducts were discharged through a column and condenser. After esterification was complete, the nitrogen gas inside the pressurized reactor was vented to reduce the reactor pressure to atmospheric pressure, and the mixture was then transferred to a 7L capacity reactor capable of vacuum reaction.

[0099] Step 2) Polycondensation The pressure in a 7 L capacity reactor was reduced from atmospheric pressure to 5 Torr (absolute pressure: 5 mmHg) over 30 minutes, while simultaneously raising the reactor temperature to 270°C over 1 hour. Polycondensation was carried out while maintaining the reactor pressure at 1 Torr (absolute pressure: 1 mmHg) or less. At the start of polycondensation, the stirring speed was set to rapid, but could be appropriately controlled if, as polycondensation progressed, the stirring force decreased due to increased reactant viscosity or the reactant temperature exceeded a predetermined level. Polycondensation continued until the intrinsic viscosity (IV) of the mixture (molten material) in the reactor reached 0.68 dl / g. If the intrinsic viscosity of the mixture in the reactor reached the desired level, the mixture was discharged from the reactor and formed into a filament, which was then solidified with a coolant and granulated to achieve an average weight of approximately 12 to 14 mg.

[0100] The granules were placed at 150°C for 1 hour to crystallize, and then added to a solid-state polymerization reactor with a capacity of 20 L. Nitrogen gas was then introduced into the reactor at a rate of 50 L / min. The reactor temperature was increased from room temperature to 140°C at a rate of 40°C / hour and maintained at 140°C for 3 hours, and then increased to 200°C at a rate of 40°C / hour and maintained at 200°C. Solid-state polymerization was carried out until the intrinsic viscosity (IV) of the granules in the reactor became 1.0 dl / g, thereby preparing a polyester copolymer.

[0101] Comparative Example 9 Step 1) Esterification TPA (2809.0 g), EG (430.2 g), CHDM (1583.9 g), and ISB (222.4 g) were added to a 10 L capacity reactor connected to a column and a water-cooled condenser. GeO2 (13.8 g) was added as a catalyst, phosphoric acid (9.1 g) as a stabilizer, Polysynthren Blue RLS (Clarient, 0.021 g) as a blue colorant, and Solvaperm Red BB (Clarient, 0.004 g) as a red colorant.

[0102] Subsequently, nitrogen gas was added to the reactor to create a pressurized environment, wherein the pressure in the reactor was 2.0 kgf / cm² higher than atmospheric pressure. 2 Furthermore, the reactor temperature was raised to 220°C over 90 minutes and maintained at 220°C for 2 hours, then raised to 260°C over another 2 hours. The mixture in the reactor was then visually inspected while the reactor temperature was maintained at 260°C for esterification for 245 minutes, until the mixture became transparent. During this process, byproducts were discharged through a column and condenser. After esterification was complete, the nitrogen gas inside the pressurized reactor was vented to reduce the reactor pressure to atmospheric pressure, and the mixture was then transferred to a 7L capacity reactor capable of vacuum reaction.

[0103] Step 2) Polycondensation The pressure in a 7 L capacity reactor was reduced from atmospheric pressure to 5 Torr (absolute pressure: 5 mmHg) over 30 minutes, while the reactor temperature was simultaneously increased to 270°C over 1 hour. Polycondensation was carried out while maintaining the reactor pressure at 1 Torr (absolute pressure: 1 mmHg) or less. At the start of polycondensation, the stirring speed was set to high, but could be appropriately controlled if, as polycondensation progressed, the viscosity of the reactants increased, the stirring force decreased, or the temperature of the reactants rose above a predetermined level. Polycondensation continued until the intrinsic viscosity (IV) of the mixture (molten material) in the reactor became 0.72 dl / g. If the intrinsic viscosity of the mixture in the reactor reached the desired level, the mixture was discharged from the reactor and formed into a filament, which was then solidified with a coolant and granulated to an average weight of approximately 12 mg to 14 mg, thus preparing the polyester copolymer.

[0104] Comparative Example 10 Step 1) Esterification TPA (2555.9 g), EG (305.5 g), CHDM (1330.3 g), and ISB (629.4 g) were added to a 10 L capacity reactor connected to a column and a water-cooled condenser. GeO2 (12.8 g) was added as a catalyst, phosphoric acid (8.5 g) as a stabilizer, Polysynthren Blue RLS (Clarient, 0.016 g) as a blue colorant, and Solvaperm Red BB (Clarient, 0.004 g) as a red colorant.

[0105] Subsequently, nitrogen gas was added to the reactor to create a pressurized environment, wherein the pressure in the reactor was 1.0 kgf / cm² higher than atmospheric pressure. 2 Furthermore, the reactor temperature was raised to 220°C over 90 minutes and maintained at 220°C for 2 hours, then raised to 250°C over another 2 hours. The mixture in the reactor was then visually inspected while the reactor temperature was maintained at 250°C for esterification for 245 minutes, until the mixture became transparent. During this process, byproducts were discharged through a column and condenser. After esterification was complete, the nitrogen gas inside the pressurized reactor was vented to reduce the reactor pressure to atmospheric pressure, and the mixture was then transferred to a 7L capacity reactor capable of vacuum reaction.

[0106] Step 2) Polycondensation The pressure in a 7 L capacity reactor was reduced from atmospheric pressure to 5 Torr (absolute pressure: 5 mmHg) over 30 minutes, while the reactor temperature was simultaneously increased to 275°C over 1 hour. Polycondensation was carried out while maintaining the reactor pressure at 1 Torr (absolute pressure: 1 mmHg) or less. At the start of polycondensation, the stirring speed was set to high, but could be appropriately controlled if, as polycondensation progressed, the viscosity of the reactants increased, the stirring force decreased, or the temperature of the reactants rose above a predetermined level. Polycondensation continued until the intrinsic viscosity (IV) of the mixture (molten material) in the reactor reached 0.70 dl / g. If the intrinsic viscosity of the mixture in the reactor reached the desired level, the mixture was discharged from the reactor and formed into a filament, which was then solidified with a coolant and granulated to an average weight of approximately 12 mg to 14 mg, thus preparing the polyester copolymer.

[0107] Experimental Examples The properties of the copolymers prepared in the examples and comparative examples are evaluated as follows.

[0108] 1) Intrinsic viscosity: The polyester copolymer was dissolved in o-chlorophenol (OCP) at a concentration of 0.12% at 150°C, and then the intrinsic viscosity was measured using an Ubbelohde viscometer in a thermostat at 35°C.

[0109] 2) Storage Modulus: The polyester copolymers prepared in the Examples and Comparative Examples were made into samples with a length of 17.5 mm, a width of 13 mm, and a thickness of 0.8 mm. The samples were measured in single cantilever mode using a TA Instruments Q800 instrument at a temperature range of 40°C to 180°C, a temperature rise rate of 3°C / min, a frequency of 1 Hz, and an amplitude of 15 μm. The value measured at 40°C was determined as the storage modulus.

[0110] 3) Melting point and heat of fusion: Melting point and heat of fusion were measured using a Mettler Toledo DSC-1 instrument. Specifically, each polyester copolymer prepared in the examples and comparative examples was processed using an injection molding machine at a temperature of approximately 250°C to 270°C to obtain injection-molded products of flat samples with a thickness of 6 mm. Then, for the polyester copolymer injection-molded products, the melting point and heat of fusion were measured under nitrogen at a temperature rise rate of +5°C / min.

[0111] 4) Glass transition temperature: The glass transition temperature was measured using a TA Instruments Q800 instrument for each polyester copolymer prepared in the examples and comparative examples at a temperature rise rate of 3 °C / min and a frequency of 10 Hz.

[0112] 5) Melting point and heat of fusion: The melting point and heat of fusion were measured under nitrogen at a temperature rise rate of +10 °C / min for each polyester copolymer prepared in the examples and comparative examples using a Mettler toledo DSC1 instrument.

[0113] 6) Measurement of draw ratio: Each polyester copolymer prepared in the Examples and Comparative Examples was melt-extruded at 290°C to prepare an unstretched film with a thickness of 300 μm. This unstretched film was then stretched in the machine direction at a temperature 30°C higher than the glass transition temperature of each copolymer. Specifically, machine-directed stretching was performed at a rate of 750% / min, and the feasibility of stretching to 400% or greater was evaluated.

[0114] The results are shown in Table 1 below.

[0115] [Table 1]

[0116] In Table 1, in the cases of Comparative Examples 1, 2, 6, 7, 9, and 10, since the polymer is amorphous, there is no melting point or heat of fusion. Amorphous resins have lower storage modulus and tensile properties compared to crystalline resins, and therefore, insufficient strength and moldability. Furthermore, in the case of Comparative Example 5, the heat of fusion is too low, meaning it exhibits properties similar to amorphous resins. Additionally, it can be confirmed that in the case of Comparative Example 8, the glass transition temperature is too low, and therefore the heat resistance is low. Meanwhile, it can be confirmed that in the cases of Examples 1 to 8 according to this disclosure, the storage modulus is high and the glass transition temperature is high, and therefore the strength and heat resistance are excellent. Furthermore, in the cases of Examples 1 to 8 according to this disclosure, the melting point and heat of fusion are high, confirming that the polymer is crystalline.

[0117] Furthermore, a draw ratio of 400% or greater means that the polyester resin has high crystallinity, and the polyesters according to this disclosure all exhibit a draw ratio of 400% or greater, while in the cases of Comparative Examples 2, 5, 6, 7, 9 and 10, they exhibit low draw properties due to low crystallinity.

Claims

1. A polyester copolymer comprising: 1) residues of a dicarboxylic acid component including terephthalic acid; and 2) residues of a diol component including isosorbide, cyclohexanedimethanol, and an acyclic diol, wherein the copolymer comprises isosorbide residues, cyclohexanedimethanol residues, and acyclic diol residues at contents of 4 to 20 mol%, 65 to 85 mol%, and 11 to 31 mol%, respectively, based on the total moles of diol component residues, and satisfies the following mathematical formula 1: [mathematical formula 1] 30 < (X * Y) / (Z * W) < 1000 in the mathematical formula 1, X is a storage modulus (unit: MPa) of the polyester copolymer at 40℃, Y is a glass transition temperature (unit: ℃) of the polyester copolymer, Z is a melting point (unit: ℃) of the polyester copolymer, and W is a heat of fusion (unit: J / g) of the polyester copolymer. 2.The polyester copolymer according to claim 1, wherein the polyester copolymer satisfies the following mathematical formula 2: [mathematical formula 2] 0.04 ≤ (ISB) / (ISB+CHDM) ≤ 0.22 in the mathematical formula 2, ISB represents mol% of the isosorbide residues based on the total moles of the diol component residues, CHDM represents mol% of the cyclohexanedimethanol residues based on the total moles of the diol component residues. 3.The polyester copolymer according to claim 1, wherein the residues of the dicarboxylic acid component further include residues of one or more selected from the group consisting of dimethyl terephthalate, isophthalic acid, 2,6-naphthalene dicarboxylic acid, diphenyl dicarboxylic acid, 4,4’-stilbene dicarboxylic acid, 2,5-furan dicarboxylic acid, and 2,5-thiophene dicarboxylic acid. 4.The polyester copolymer according to claim 1, wherein the storage modulus (X) of the polyester copolymer is 1700 to 2100 MPa. 5.The polyester copolymer according to claim 1, wherein the glass transition temperature (Y) of the polyester copolymer is 85 to 115℃. 6.The polyester copolymer according to claim 1, wherein the melting point (Z) of the polyester copolymer is 225 to 270℃. 7.The polyester copolymer according to claim 1, wherein the heat of fusion (W) of the polyester copolymer is 1 to 20 J / g.

8. The polyester copolymer of claim 1, wherein the acyclic diol is C 2-10 alkylene glycol. 9.The polyester copolymer according to claim 1, wherein the acyclic diol is ethylene glycol or diethylene glycol.

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