POLYESTER COPOLYMER HAVING EXCELLENT STRENGTH, AND PRODUCT COMPRISING THE SAME

Abstract

The present disclosure relates to a polyester copolymer having excellent strength and heat resistance, and a product comprising the same.

Claims

1. A polyester copolymer comprising 1) residues of dicarboxylic acid components comprising terephthalic acid; and 2) residues of diol components comprising isosorbide, cyclohexanedimethanol, and non-cyclic diol, wherein the copolymer comprises the isosorbide residues, cyclohexanedimethanol residues, and non-cyclic diol residues respectively in the content of 4 to 20 mol %, 65 to 85 mol %, and 11 to 31 mol %, based on the total number of moles of the diol component residues, and satisfies the following Mathematical Formula 1:
30<(X*Y)/(Z*W)<1000  [Mathematical Formula 1] in the Mathematical Formula 1, X is storage modulus (unit: MPa) of the polyester copolymer at 40° C., Y is glass transition temperature (unit: ° C.) of the polyester copolymer, Z is melting point (unit: ° C.) of the polyester copolymer, and W is 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:
0.04≤(ISB)/(ISB+CHDM)≤0.22  [Mathematical Formula 2] in the Mathematical Formula 2, ISB denotes mol % of the isosorbide residues, based on the total number of moles of the diol component residues, CHDM denotes mol % of cyclohexanedimethanol residues, based on the total number of moles of the diol component residues.

3. The polyester copolymer according to claim 1, wherein the residues of dicarboxylic acid components further comprise residues of one or more selected from the group consisting of dimethyl terephthalic acid, isophthalic acid, 2,6-naphthalene dicarboxylic acid, diphenyl dicarboxylic acid, 4,4′-stilbene dicarboxylic acid, 2,5-furane dicarboxylic acid, and 2,5-thiophene dicarboxylic acid.

4. The polyester copolymer according to claim 1, wherein storage modulus (X) of the polyester copolymer is 1700 to 2100 MPa.

5. The polyester copolymer according to claim 1, wherein glass transition temperature (Y) of the polyester copolymer is 85 to 115° C.

6. The polyester copolymer according to claim 1, wherein melting point (Z) of the polyester copolymer is 225 to 270° C.

7. The polyester copolymer according to claim 1, wherein heat of fusion (W) of the polyester copolymer is 1 to 20 J/g.

8. The polyester copolymer according to claim 1, wherein the non-cyclic diol is C.sub.2-10 alkylenediol.

9. The polyester copolymer according to claim 1, wherein the non-cyclic diol is ethylene glycol or diethylene glycol.

Description

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0054] Hereinafter, preferable examples will be presented for better understanding of the invention. However, these examples are presented only for better understanding of the invention, and the scope of the invention is not limited thereby.

Example 1

[0055] Step 1) Esterification

[0056] Into a reactor with a capacity of 10 L to which a column, and a condenser that can be cooled by water are connected, TPA (terephthalic acid; 2666.7 g), EG (ethylene glycol; 597.6 g), CHDM (1,4-cyclohexanedimethanol; 1573.0 g), and ISB (isosorbide; 281.4 g) were added, and GeO2 (13.1 g) as a catalyst, phosphoric acid (8.7 g) as a stabilizer, Polysynthren Blue RLS (Clarient, 0.016 g) as blue toner, Solvaperm Red BB (Clarient, 0.004 g) as red toner, and trimellitic anhydride (0.4 g) as a branching agent were added.

[0057] Subsequently, nitrogen was added in the reactor to make a pressurized state where the pressure of the reactor is 1.0 kgf/cm.sup.2 higher than atmospheric pressure. Further, the temperature of the reactor was raised to 220° C. over 90 minutes, and maintained at 220° C. for 2 hours, and then, raised to 260° C. over 2 hours. And then, the mixture in the reactor was observed with the naked eye, and until the mixture became transparent, while maintaining the temperature of the reactor at 260° C., esterification was progressed for 245 minutes. During this process, by-products were discharged through the column and condenser. After the esterification was completed, nitrogen inside the reactor of a pressurized state was discharged outside to lower the pressure of the reactor to atmospheric pressure, and then, the mixture in the reactor was transferred to a reactor with a capacity of 7 L where a vacuum reaction can be progressed.

[0058] Step 2) Condensation Polymerization

[0059] The pressure of the reactor with a capacity of 7 L was lowered from atmospheric pressure state to 5 Torr (absolute pressure: 5 mmHg) over 30 minutes, and simultaneously, the temperature of the reactor was raised to 265° C. over 1 hour, and while maintaining the pressure of the reactor at 1 Torr (absolute pressure: 1 mmHg) or less, condensation polymerization was conducted. At the beginning of condensation polymerization, a stirring speed was set rapid, but if a stirring force decreases or the temperature of the reactant increases beyond predetermined temperature due to viscosity increase of the reactant with the progression of condensation polymerization, the stirring speed may be appropriately controlled. The condensation polymerization was progressed until intrinsic viscosity (IV) of the mixture (molten material) in the reactor became 0.71 dl/g. If the intrinsic viscosity of the mixture in the reactor reached a desired level, the mixture was discharged outside the reactor and stranded, and it was solidified with a coolant, and then, granulated such that the average weight became about 12 to 14 mg.

[0060] The particles were left at 150° C. for 1 hour to crystallize, and then, added into a solid state polymerization reactor with a capacity of 20 L. And then, nitrogen was flowed into the reactor at a speed of 50 L/min. Wherein, the temperature of the reactor was raised from a room temperature to 140° C. at a speed of 40° C./hour, and maintained at 140° C. for 3 hours, and then, raised to 190° C. at a speed of and maintained at 190° C. The solid state polymerization was progressed until intrinsic viscosity (IV) of particles in the reactor became 0.80 dl/g, thus preparing polyester copolymer.

Example 2

[0061] Step 1) Esterification

[0062] Into a reactor with a capacity of 10 L to which a column, and a condenser that can be cooled by water are connected, TPA (2374.1 g), EG (150.7 g), CHDM (1482.8 g), and ISB (751.7 g) were added, and GeO2 (13.1 g) as a catalyst, phosphoric acid (8.7 g) as a stabilizer, Polysynthren Blue RLS (Clarient, 0.019 g) as blue toner, Solvaperm Red BB (Clarient, 0.004 g) as red toner and high-density polyethylene (SK GeO centric Co., Ltd. YUZEX 2600S; 0.0038 g) as a crystallization agent were added.

[0063] Subsequently, nitrogen was added in the reactor to make a pressurized state where the pressure of the reactor is 2.0 kgf/cm.sup.2 higher than atmospheric pressure. Further, the temperature of the reactor was raised to 220° C. over 90 minutes, and maintained at 220° C. for 2 hours, and then, raised to 280° C. over 2 hours. And then, the mixture in the reactor was observed with the naked eye, and until the mixture became transparent, while maintaining the temperature of the reactor at 280° C., esterification was progressed for 245 minutes. During this process, by-products were discharged through the column and condenser. After the esterification was completed, nitrogen inside the reactor of a pressurized state was discharged outside to lower the pressure of the reactor to atmospheric pressure, and then, the mixture in the reactor was transferred to a reactor with a capacity of 7 L where a vacuum reaction can be progressed

[0064] Step 2) Condensation Polymerization

[0065] The pressure of the reactor with a capacity of 7 L was lowered from atmospheric pressure state to 5 Torr (absolute pressure: 5 mmHg) over 30 minutes, and simultaneously, the temperature of the reactor was raised to 290° C. over 1 hour, and while maintaining the pressure of the reactor at 1 Torr (absolute pressure: 1 mmHg) or less, condensation polymerization was conducted. At the beginning of condensation polymerization, a stirring speed was set rapid, but if a stirring force decreases or the temperature of the reactant increases beyond predetermined temperature due to viscosity increase of the reactant with the progression of condensation polymerization, the stirring speed may be appropriately controlled. The condensation polymerization was progressed until 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 a desired level, the mixture was discharged outside the reactor and stranded, and it was solidified with a coolant, and then, granulated such that the average weight became about 12 to 14 mg, thus preparing polyester copolymer.

Example 3

[0066] Step 1) Esterification

[0067] Into a reactor with a capacity of 10 L to which a column, and a condenser that can be cooled by water are connected, TPA (2375.9 g), EG (248.5 g), CHDM (1690.0 g), and ISB (417.9 g) were added, and GeO2 (13.1 g) as a catalyst, phosphoric acid (8.7 g) as a stabilizer, Polysynthren Blue RLS (Clarient, 0.019 g) as blue toner, and Solvaperm Red BB (Clarient, 0.004 g) as red toner were added.

[0068] Subsequently, nitrogen was added in the reactor to make a pressurized state where the pressure of the reactor is 1.0 kgf/cm.sup.2 higher than atmospheric pressure. Further, the temperature of the reactor was raised to 220° C. over 90 minutes, and maintained at 220° C. for 2 hours, and then, raised to 270° C. over 2 hours. And then, the mixture in the reactor was observed with the naked eye, and until the mixture became transparent, while maintaining the temperature of the reactor at 270° C., esterification was progressed for 245 minutes. During this process, by-products were discharged through the column and condenser. After the esterification was completed, nitrogen inside the reactor of a pressurized state was discharged outside to lower the pressure of the reactor to atmospheric pressure, and then, the mixture in the reactor was transferred to a reactor with a capacity of 7 L where a vacuum reaction can be progressed

[0069] Step 2) Condensation Polymerization

[0070] The pressure of the reactor with a capacity of 7 L was lowered from atmospheric pressure state to 5 Torr (absolute pressure: 5 mmHg) over 30 minutes, and simultaneously, the temperature of the reactor was raised to 290° C. over 1 hour, and while maintaining the pressure of the reactor at 1 Torr (absolute pressure: 1 mmHg) or less, condensation polymerization was conducted. At the beginning of condensation polymerization, a stirring speed was set rapid, but if a stirring force decreases or the temperature of the reactant increases beyond predetermined temperature due to viscosity increase of the reactant with the progression of condensation polymerization, the stirring speed may be appropriately controlled. The condensation polymerization was progressed until intrinsic viscosity (IV) of the mixture (molten material) in the reactor became 0.74 dl/g. If the intrinsic viscosity of the mixture in the reactor reached a desired level, the mixture was discharged outside the reactor and stranded, and it was solidified with a coolant, and then, granulated such that the average weight became about 12 to 14 mg.

[0071] The particles were left at 150° C. for 1 hour to crystallize, and then, added into a solid state polymerization reactor with a capacity of 20 L. And then, nitrogen was flowed into the reactor at a speed of 50 L/min. Wherein, the temperature of the reactor was raised from a room temperature to 140° C. at a speed of 40° C./hour, and maintained at 140° C. for 3 hours, and then, raised to 200° C. at a speed of and maintained at 200° C. The solid state polymerization was progressed until intrinsic viscosity (IV) of particles in the reactor became 0.95 dl/g, thus preparing polyester copolymer.

Example 4

[0072] Step 1) Esterification

[0073] Into a reactor with a capacity of 10 L to which a column, and a condenser that can be cooled by water are connected, TPA (3127.4 g), EG (257.0 g), CHDM (2360.2 g), and ISB (302.6 g) were added, and GeO2 (16.4 g) as a catalyst, phosphoric acid (10.9 g) as a stabilizer, Polysynthren Blue RLS (Clarient, 0.020 g) as blue toner, Solvaperm Red BB (Clarient, 0.005 g) as red toner and Irganox 1076 (0.5 g) as an antioxidant were added.

[0074] Subsequently, nitrogen was added in the reactor to make a pressurized state where the pressure of the reactor is 1.0 kgf/cm.sup.2 higher than atmospheric pressure. Further, the temperature of the reactor was raised to 220° C. over 90 minutes, and maintained at 220° C. for 2 hours, and then, raised to 240° C. over 2 hours. And then, the mixture in the reactor was observed with the naked eye, and until the mixture became transparent, while maintaining the temperature of the reactor at 240° C., esterification was progressed for 245 minutes. During this process, by-products were discharged through the column and condenser. After the esterification was completed, nitrogen inside the reactor of a pressurized state was discharged outside to lower the pressure of the reactor to atmospheric pressure, and then, the mixture in the reactor was transferred to a reactor with a capacity of 7 L where a vacuum reaction can be progressed

[0075] Step 2) Condensation Polymerization

[0076] The pressure of the reactor with a capacity of 7 L was lowered from atmospheric pressure state to 5 Torr (absolute pressure: 5 mmHg) over 30 minutes, and simultaneously, the temperature of the reactor was raised to 290° C. over 1 hour, and while maintaining the pressure of the reactor at 1 Torr (absolute pressure: 1 mmHg) or less, condensation polymerization was conducted. At the beginning of condensation polymerization, a stirring speed was set rapid, but if a stirring force decreases or the temperature of the reactant increases beyond predetermined temperature due to viscosity increase of the reactant with the progression of condensation polymerization, the stirring speed may be appropriately controlled. The condensation polymerization was progressed until intrinsic viscosity (IV) of the mixture (molten material) in the reactor became 0.68 dl/g. If the intrinsic viscosity of the mixture in the reactor reached a desired level, the mixture was discharged outside the reactor and stranded, and it was solidified with a coolant, and then, granulated such that the average weight became about 12 to 14 mg.

[0077] The particles were left at 150° C. for 1 hour to crystallize, and then, added into a solid state polymerization reactor with a capacity of 20 L. And then, nitrogen was flowed into the reactor at a speed of 50 L/min. Wherein, the temperature of the reactor was raised from a room temperature to 140° C. at a speed of 40° C./hour, and maintained at 140° C. for 3 hours, and then, raised to 220° C. at a speed of and maintained at 220° C. The solid state polymerization was progressed until intrinsic viscosity (IV) of particles in the reactor became 1.0 dl/g, thus preparing polyester copolymer.

Example 5

[0078] Step 1) Esterification

[0079] Into a reactor with a capacity of 10 L to which a column, and a condenser that can be cooled by water are connected, TPA (2548.0 g), EG (304.5 g), CHDM (1635.6 g), and ISB (425.8 g) were added, and GeO2 (13.1 g) as a catalyst, phosphoric acid (8.7 g) as a stabilizer, Polysynthren Blue RLS (Clarient, 0.020 g) as blue toner, Solvaperm Red BB (Clarient, 0.008 g) as red toner and Irganox 1076 (0.4 g) as an antioxidant were added.

[0080] Subsequently, nitrogen was added in the reactor to make a pressurized state where the pressure of the reactor is 1.0 kgf/cm.sup.2 higher than atmospheric pressure. Further, the temperature of the reactor was raised to 220° C. over 90 minutes, and maintained at 220° C. for 2 hours, and then, raised to 255° C. over 2 hours. And then, the mixture in the reactor was observed with the naked eye, and until the mixture became transparent, while maintaining the temperature of the reactor at 255° C., esterification was progressed for 245 minutes. During this process, by-products were discharged through the column and condenser. After the esterification was completed, nitrogen inside the reactor of a pressurized state was discharged outside to lower the pressure of the reactor to atmospheric pressure, and then, the mixture in the reactor was transferred to a reactor with a capacity of 7 L where a vacuum reaction can be progressed

[0081] Step 2) Condensation Polymerization

[0082] The pressure of the reactor with a capacity of 7 L was lowered from atmospheric pressure state to 5 Torr (absolute pressure: 5 mmHg) over 30 minutes, and simultaneously, the temperature of the reactor was raised to 280° C. over 1 hour, and while maintaining the pressure of the reactor at 1 Torr (absolute pressure: 1 mmHg) or less, condensation polymerization was conducted. At the beginning of condensation polymerization, a stirring speed was set rapid, but if a stirring force decreases or the temperature of the reactant increases beyond predetermined temperature due to viscosity increase of the reactant with the progression of condensation polymerization, the stirring speed may be appropriately controlled. The condensation polymerization was progressed until 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 a desired level, the mixture was discharged outside the reactor and stranded, and it was solidified with a coolant, and then, granulated such that the average weight became about 12 to 14 mg.

[0083] The particles were left at 150° C. for 1 hour to crystallize, and then, added into a solid state polymerization reactor with a capacity of 20 L. And then, nitrogen was flowed into the reactor at a speed of 50 L/min. Wherein, the temperature of the reactor was raised from a room temperature to 140° C. at a speed of 40° C./hour, and maintained at 140° C. for 3 hours, and then, raised to 220° C. at a speed of and maintained at 220° C. The solid state polymerization was progressed until intrinsic viscosity (IV) of particles in the reactor became 1.2 dl/g, thus preparing polyester copolymer.

Example 6

[0084] Step 1) Esterification

[0085] Into a reactor with a capacity of 10 L to which a column, and a condenser that can be cooled by water are connected, TPA (2382.2 g), EG (115.7 g), CHDM (1508.5 g), and ISB (398.1 g) were added, and GeO2 (12.4 g) as a catalyst, phosphoric acid (8.2 g) as a stabilizer, Polysynthren Blue RLS (Clarient, 0.027 g) as blue toner, Solvaperm Red BB (Clarient, 0.008 g) as red toner and Irganox 1076 (0.38 g) as an antioxidant were added.

[0086] Subsequently, nitrogen was added in the reactor to make a pressurized state where the pressure of the reactor is 0.5 kgf/cm.sup.2 higher than atmospheric pressure. Further, the temperature of the reactor was raised to 220° C. over 90 minutes, and maintained at 220° C. for 2 hours, and then, raised to 250° C. over 2 hours. And then, the mixture in the reactor was observed with the naked eye, and until the mixture became transparent, while maintaining the temperature of the reactor at 250° C., esterification was progressed for 245 minutes. During this process, by-products were discharged through the column and condenser. After the esterification was completed, nitrogen inside the reactor of a pressurized state was discharged outside to lower the pressure of the reactor to atmospheric pressure, and then, the mixture in the reactor was transferred to a reactor with a capacity of 7 L where a vacuum reaction can be progressed

[0087] Step 2) Condensation Polymerization

[0088] The pressure of the reactor with a capacity of 7 L was lowered from atmospheric pressure state to 5 Torr (absolute pressure: 5 mmHg) over 30 minutes, and simultaneously, the temperature of the reactor was raised to 290° C. over 1 hour, and while maintaining the pressure of the reactor at 1 Torr (absolute pressure: 1 mmHg) or less, condensation polymerization was conducted. At the beginning of condensation polymerization, a stirring speed was set rapid, but if a stirring force decreases or the temperature of the reactant increases beyond a predetermined temperature due to viscosity increase of the reactant with the progression of condensation polymerization, the stirring speed may be appropriately controlled. The condensation polymerization was progressed until 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 a desired level, the mixture was discharged outside the reactor and stranded, and it was solidified with a coolant, and then, granulated such that the average weight became about 12 to 14 mg.

[0089] The particles were left at 150° C. for 1 hour to crystallize, and then, added into a solid state polymerization reactor with a capacity of 20 L. And then, nitrogen was flowed into the reactor at a speed of 50 L/min. Wherein, the temperature of the reactor was raised from a room temperature to 140° C. at a speed of 40° C./hour, and maintained at 140° C. for 3 hours, and then, raised to 205° C. at a speed of and maintained at 205° C. The solid state polymerization was progressed until intrinsic viscosity (IV) of particles in the reactor became 1.1 dl/g, thus preparing polyester copolymer.

Example 7

[0090] Step 1) Esterification

[0091] Into a reactor with a capacity of 10 L to which a column, and a condenser that can be cooled by water are connected, DMT (dimethyl terephthalate; 3126.6 g), EG (1229.1 g), CHDM (1740.6 g), and ISB (753.0 g) were added, and GeO2 (13.8 g) as a catalyst, phosphoric acid (9.1 g) as a stabilizer, Polysynthren Blue RLS (Clarient, 0.021 g) as blue toner, and Solvaperm Red BB (Clarient, 0.008 g) as red toner were added.

[0092] Subsequently, nitrogen was added in the reactor to adjust the pressure of the reactor to atmospheric pressure. Further, the temperature of the reactor was raised to 220° C. over 90 minutes, and maintained at 220° C. for 2 hours, and then, raised to 240° C. over 2 hours. And then, the mixture in the reactor was observed with the naked eye, and until the mixture became transparent, while maintaining the temperature of the reactor at 240° C., esterification was progressed for 245 minutes. During this process, by-products were discharged through the column and condenser. After the esterification was completed, the mixture in the reactor was transferred to a reactor with a capacity of 7 L where a vacuum reaction can be progressed.

[0093] Step 2) Condensation Polymerization

[0094] The pressure of the reactor with a capacity of 7 L was lowered from atmospheric pressure state to 5 Torr (absolute pressure: 5 mmHg) over 30 minutes, and simultaneously, the temperature of the reactor was raised to 270° C. over 1 hour, and while maintaining the pressure of the reactor at 1 Torr (absolute pressure: 1 mmHg) or less, condensation polymerization was conducted. At the beginning of condensation polymerization, a stirring speed was set rapid, but if a stirring force decreases or the temperature of the reactant increases beyond a predetermined temperature due to viscosity increase of the reactant with the progression of condensation polymerization, the stirring speed may be appropriately controlled. The condensation polymerization was progressed until 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 a desired level, the mixture was discharged outside the reactor and stranded, and it was solidified with a coolant, and then, granulated such that the average weight became about 12 to 14 mg.

[0095] The particles were left at 150° C. for 1 hour to crystallize, and then, added into a solid state polymerization reactor with a capacity of 20 L. And then, nitrogen was flowed into the reactor at a speed of 50 L/min. Wherein, the temperature of the reactor was raised from a room temperature to 140° C. at a speed of 40° C./hour, and maintained at 140° C. for 3 hours, and then, raised to 200° C. at a speed of and maintained at 200° C. The solid state polymerization was progressed until intrinsic viscosity (IV) of particles in the reactor became 1.0 dl/g, thus preparing polyester copolymer.

Example 8

[0096] Step 1) Esterification

[0097] Into a reactor with a capacity of 10 L to which a column, and a condenser that can be cooled by water are connected, 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, and GeO2 (13.1 g) as a catalyst, phosphoric acid (8.7 g) as a stabilizer, Polysynthren Blue RLS (Clarient, 0.020 g) as blue toner, and Solvaperm Red BB (Clarient, g) as red toner were added.

[0098] Subsequently, nitrogen was added in the reactor to make a pressurized state where the pressure of the reactor is 1.0 kgf/cm.sup.2 higher than atmospheric pressure. Further, the temperature of the reactor was raised to 220° C. over 90 minutes, and maintained at 220° C. for 2 hours, and then, raised to 260° C. over 2 hours. And then, the mixture in the reactor was observed with the naked eye, and until the mixture became transparent, while maintaining the temperature of the reactor at 260° C., esterification was progressed for 245 minutes. During this process, by-products were discharged through the column and condenser. After the esterification was completed, nitrogen inside the reactor of a pressurized state was discharged outside to lower the pressure of the reactor to atmospheric pressure, and then, the mixture in the reactor was transferred to a reactor with a capacity of 7 L where a vacuum reaction can be progressed

[0099] Step 2) Condensation Polymerization

[0100] The pressure of the reactor with a capacity of 7 L was lowered from atmospheric pressure state to 5 Torr (absolute pressure: 5 mmHg) over 30 minutes, and simultaneously, the temperature of the reactor was raised to 285° C. over 1 hour, and while maintaining the pressure of the reactor at 1 Torr (absolute pressure: 1 mmHg) or less, condensation polymerization was conducted. At the beginning of condensation polymerization, a stirring speed was set rapid, but if a stirring force decreases or the temperature of the reactant increases beyond a predetermined temperature due to viscosity increase of the reactant with the progression of condensation polymerization, the stirring speed may be appropriately controlled. The condensation polymerization was progressed until 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 a desired level, the mixture was discharged outside the reactor and stranded, and it was solidified with a coolant, and then, granulated such that the average weight became about 12 to 14 mg.

[0101] The particles were left at 150° C. for 1 hour to crystallize, and then, added into a solid state polymerization reactor with a capacity of 20 L. And then, nitrogen was flowed into the reactor at a speed of 50 L/min. Wherein, the temperature of the reactor was raised from a room temperature to 140° C. at a speed of 40° C./hour, and maintained at 140° C. for 3 hours, and then, raised to 200° C. at a speed of 40° C. hour, and maintained at 200° C. The solid state polymerization was progressed until intrinsic viscosity (IV) of particles in the reactor became 1.2 dl/g, thus preparing polyester copolymer.

Comparative Example 1

[0102] Step 1) Esterification

[0103] Into a reactor with a capacity of 10 L to which a column, and a condenser that can be cooled by water are connected, TPA (3417.6 g), EG (1314.8 g), and ISB (661.3 g) were added, and GeO2 (5.5 g) as a catalyst, phosphoric acid (3.0 g) as a stabilizer, Polysynthren Blue RLS (Clarient, 0.013 g) as blue toner, and Solvaperm Red BB (Clarient, 0.004 g) as red toner were added.

[0104] Subsequently, nitrogen was added in the reactor to make a pressurized state where the pressure of the reactor is 0.5 kgf/cm.sup.2 higher than atmospheric pressure. Further, the temperature of the reactor was raised to 220° C. over 90 minutes, and maintained at 220° C. for 2 hours, and then, raised to 260° C. over 2 hours. And then, the mixture in the reactor was observed with the naked eye, and until the mixture became transparent, while maintaining the temperature of the reactor at 260° C., esterification was progressed for 245 minutes. During this process, by-products were discharged through the column and condenser. After the esterification was completed, nitrogen inside the reactor of a pressurized state was discharged outside to lower the pressure of the reactor to atmospheric pressure, and then, the mixture in the reactor was transferred to a reactor with a capacity of 7 L where a vacuum reaction can be progressed.

[0105] Step 2) Condensation Polymerization

[0106] The pressure of the reactor with a capacity of 7 L was lowered from atmospheric pressure state to 5 Torr (absolute pressure: 5 mmHg) over 30 minutes, and simultaneously, the temperature of the reactor was raised to 275° C. over 1 hour, and while maintaining the pressure of the reactor at 1 Torr (absolute pressure: 1 mmHg) or less, condensation polymerization was conducted. At the beginning of condensation polymerization, a stirring speed was set rapid, but if a stirring force decreases or the temperature of the reactant increases beyond a predetermined temperature due to viscosity increase of the reactant with the progression of condensation polymerization, the stirring speed may be appropriately controlled. The condensation polymerization was progressed until 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 a desired level, the mixture was discharged outside the reactor and stranded, and it was solidified with a coolant, and then, granulated such that the average weight became about 12 to 14 mg, thus preparing polyester copolymer.

Comparative Example 2

[0107] Step 1) Esterification

[0108] Into a reactor with a capacity of 10 L to which a column, and a condenser that can be cooled by water are connected, TPA (2657.1 g), EG (793.9 g), CHDM (1498.2 g), and ISB (701.1 g) were added, and GeO2 (13.1 g) as a catalyst, phosphoric acid (8.7 g) as a stabilizer, Polysynthren Blue RLS (Clarient, 0.012 g) as blue toner, and Solvaperm Red BB (Clarient, 0.004 g) as red toner were added.

[0109] Subsequently, nitrogen was added in the reactor to make a pressurized state where the pressure of the reactor is 1.0 kgf/cm.sup.2 higher than atmospheric pressure. Further, the temperature of the reactor was raised to 220° C. over 90 minutes, and maintained at 220° C. for 2 hours, and then, raised to 255° C. over 2 hours. And then, the mixture in the reactor was observed with the naked eye, and until the mixture became transparent, while maintaining the temperature of the reactor at 255° C., esterification was progressed for 245 minutes. During this process, by-products were discharged through the column and condenser. After the esterification was completed, nitrogen inside the reactor of a pressurized state was discharged outside to lower the pressure of the reactor to atmospheric pressure, and then, the mixture in the reactor was transferred to a reactor with a capacity of 7 L where a vacuum reaction can be progressed

[0110] Step 2) Condensation Polymerization

[0111] The pressure of the reactor with a capacity of 7 L was lowered from atmospheric pressure state to 5 Torr (absolute pressure: 5 mmHg) over 30 minutes, and simultaneously, the temperature of the reactor was raised to 285° C. over 1 hour, and while maintaining the pressure of the reactor at 1 Torr (absolute pressure: 1 mmHg) or less, condensation polymerization was conducted. At the beginning of condensation polymerization, a stirring speed was set rapid, but if a stirring force decreases or the temperature of the reactant increases beyond a predetermined temperature due to viscosity increase of the reactant with the progression of condensation polymerization, the stirring speed may be appropriately controlled. The condensation polymerization was progressed until 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 a desired level, the mixture was discharged outside the reactor and stranded, and it was solidified with a coolant, and then, granulated such that the average weight became about 12 to 14 mg, thus preparing polyester copolymer.

Comparative Example 3

[0112] Step 1) Esterification

[0113] Into a reactor with a capacity of 10 L to which a column, and a condenser that can be cooled by water are connected, TPA (2209.6 g), CHDM (1859.2 g), and ISB (252.6 g) were added, and GeO2 (12.8 g) as a catalyst, phosphoric acid (8.5 g) as a stabilizer, Polysynthren Blue RLS (Clarient, 0.012 g) as blue toner, and Solvaperm Red BB (Clarient, 0.004 g) as red toner were added.

[0114] Subsequently, nitrogen was added in the reactor to make a pressurized state where the pressure of the reactor is 2.0 kgf/cm.sup.2 higher than atmospheric pressure. Further, the temperature of the reactor was raised to 220° C. over 90 minutes, and maintained at 220° C. for 2 hours, and then, raised to 250° C. over 2 hours. And then, the mixture in the reactor was observed with the naked eye, and until the mixture became transparent, while maintaining the temperature of the reactor at 250° C., esterification was progressed for 245 minutes. During this process, by-products were discharged through the column and condenser. After the esterification was completed, nitrogen inside the reactor of a pressurized state was discharged outside to lower the pressure of the reactor to atmospheric pressure, and then, the mixture in the reactor was transferred to a reactor with a capacity of 7 L where a vacuum reaction can be progressed

[0115] Step 2) Condensation Polymerization

[0116] The pressure of the reactor with a capacity of 7 L was lowered from atmospheric pressure state to 5 Torr (absolute pressure: 5 mmHg) over 30 minutes, and simultaneously, the temperature of the reactor was raised to 270° C. over 1 hour, and while maintaining the pressure of the reactor at 1 Torr (absolute pressure: 1 mmHg) or less, condensation polymerization was conducted. At the beginning of condensation polymerization, a stirring speed was set rapid, but if a stirring force decreases or the temperature of the reactant increases beyond a predetermined temperature due to viscosity increase of the reactant with the progression of condensation polymerization, the stirring speed may be appropriately controlled. The condensation polymerization was progressed until 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 a desired level, the mixture was discharged outside the reactor and stranded, and it was solidified with a coolant, and then, granulated such that the average weight became about 12 to 14 mg.

[0117] The particles were left at 150° C. for 1 hour to crystallize, and then, added into a solid state polymerization reactor with a capacity of 20 L. And then, nitrogen was flowed into the reactor at a speed of 50 L/min. Wherein, the temperature of the reactor was raised from a room temperature to 140° C. at a speed of 40° C./hour, and maintained at 140° C. for 3 hours, and then, raised to 200° C. at a speed of and maintained at 200° C. The solid state polymerization was progressed until intrinsic viscosity (IV) of particles in the reactor became 0.95 dl/g, thus preparing polyester copolymer.

Comparative Example 4

[0118] Step 1) Esterification

[0119] Into a reactor with a capacity of 10 L to which a column, and a condenser that can be cooled by water are connected, TPA (2377.9 g), CHDM (1835.9 g), and ISB (648.3 g) were added, and GeO2 (13.8 g) as a catalyst, phosphoric acid (9.1 g) as a stabilizer, Polysynthren Blue RLS (Clarient, 0.021 g) as blue toner, Solvaperm Red BB (Clarient, 0.004 g) as red toner, and Irganox 1076 (0.42 g) as an antioxidant were added.

[0120] Subsequently, nitrogen was added in the reactor to make a pressurized state where the pressure of the reactor is 1.0 kgf/cm.sup.2 higher than atmospheric pressure. Further, the temperature of the reactor was raised to 220° C. over 90 minutes, and maintained at 220° C. for 2 hours, and then, raised to 265° C. over 2 hours. And then, the mixture in the reactor was observed with the naked eye, and until the mixture became transparent, while maintaining the temperature of the reactor at 265° C., esterification was progressed for 245 minutes. During this process, by-products were discharged through the column and condenser. After the esterification was completed, nitrogen inside the reactor of a pressurized state was discharged outside to lower the pressure of the reactor to atmospheric pressure, and then, the mixture in the reactor was transferred to a reactor with a capacity of 7 L where a vacuum reaction can be progressed

[0121] Step 2) Condensation Polymerization

[0122] The pressure of the reactor with a capacity of 7 L was lowered from atmospheric pressure state to 5 Torr (absolute pressure: 5 mmHg) over 30 minutes, and simultaneously, the temperature of the reactor was raised to 275° C. over 1 hour, and while maintaining the pressure of the reactor at 1 Torr (absolute pressure: 1 mmHg) or less, condensation polymerization was conducted. At the beginning of condensation polymerization, a stirring speed was set rapid, but if a stirring force decreases or the temperature of the reactant increases beyond a predetermined temperature due to viscosity increase of the reactant with the progression of condensation polymerization, the stirring speed may be appropriately controlled. The condensation polymerization was progressed until intrinsic viscosity (IV) of the mixture (molten material) in the reactor became 0.68 dl/g. If the intrinsic viscosity of the mixture in the reactor reached a desired level, the mixture was discharged outside the reactor and stranded, and it was solidified with a coolant, and then, granulated such that the average weight became about 12 to 14 mg.

[0123] The particles were left at 150° C. for 1 hour to crystallize, and then, added into a solid state polymerization reactor with a capacity of 20 L. And then, nitrogen was flowed into the reactor at a speed of 50 L/min. Wherein, the temperature of the reactor was raised from a room temperature to 140° C. at a speed of 40° C./hour, and maintained at 140° C. for 3 hours, and then, raised to 200° C. at a speed of and maintained at 200° C. The solid state polymerization was progressed until intrinsic viscosity (IV) of particles in the reactor became 1.0 dl/g, thus preparing polyester copolymer.

Comparative Example 5

[0124] Step 1) Esterification

[0125] Into a reactor with a capacity of 10 L to which a column, and a condenser that can be cooled by water are connected, TPA (2234.8 g), CHDM (1512.1 g), and ISB (825.5 g) were added, and GeO2 (12.9 g) as a catalyst, phosphoric acid (8.6 g) as a stabilizer, Polysynthren Blue RLS (Clarient, 0.020 g) as blue toner, Solvaperm Red BB (Clarient, 0.004 g) as red toner and high-density polyethylene (SK GeO centric YUZEX 2600S; 0.3950 g) as a crystallization agent were added.

[0126] Subsequently, nitrogen was added in the reactor to make a pressurized state where the pressure of the reactor is 0.5 kgf/cm.sup.2 higher than atmospheric pressure. Further, the temperature of the reactor was raised to 220° C. over 90 minutes, and maintained at 220° C. for 2 hours, and then, raised to 260° C. over 2 hours. And then, the mixture in the reactor was observed with the naked eye, and until the mixture became transparent, while maintaining the temperature of the reactor at 260° C., esterification was progressed for 245 minutes. During this process, by-products were discharged through the column and condenser. After the esterification was completed, nitrogen inside the reactor of a pressurized state was discharged outside to lower the pressure of the reactor to atmospheric pressure, and then, the mixture in the reactor was transferred to a reactor with a capacity of 7 L where a vacuum reaction can be progressed.

[0127] Step 2) Condensation Polymerization

[0128] The pressure of the reactor with a capacity of 7 L was lowered from atmospheric pressure state to 5 Torr (absolute pressure: 5 mmHg) over 30 minutes, and simultaneously, the temperature of the reactor was raised to 275° C. over 1 hour, and while maintaining the pressure of the reactor at 1 Torr (absolute pressure: 1 mmHg) or less, condensation polymerization was conducted. At the beginning of condensation polymerization, a stirring speed was set rapid, but if a stirring force decreases or the temperature of the reactant increases beyond a predetermined temperature due to viscosity increase of the reactant with the progression of condensation polymerization, the stirring speed may be appropriately controlled. The condensation polymerization was progressed until 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 a desired level, the mixture was discharged outside the reactor and stranded, and it was solidified with a coolant, and then, granulated such that the average weight became about 12 to 14 mg.

[0129] The particles were left at 150° C. for 1 hour to crystallize, and then, added into a solid state polymerization reactor with a capacity of 20 L. And then, nitrogen was flowed into the reactor at a speed of 50 L/min. Wherein, the temperature of the reactor was raised from a room temperature to 140° C. at a speed of 40° C./hour, and maintained at 140° C. for 3 hours, and then, raised to 200° C. at a speed of and maintained at 200° C. The solid state polymerization was progressed until intrinsic viscosity (IV) of particles in the reactor became 0.98 dl/g, thus preparing polyester copolymer.

Comparative Example 6

[0130] Step 1) Esterification

[0131] Into a reactor with a capacity to 10 L in which a column, and a condenser that can be cooled by water are connected, TPA (2612.0 g), EG (595.1 g), CHDM (1404.8 g), and ISB (160.8 g) were added, and GeO2 (12.4 g) as a catalyst, phosphoric acid (8.2 g) as a stabilizer, Polysynthren Blue RLS (Clarient, 0.011 g) as blue toner, Solvaperm Red BB (Clarient, 0.004 g) as red toner and trimellitic anhydride (0.38 g) as a branching agent were added.

[0132] Subsequently, nitrogen was added in the reactor to make a pressurized state where the pressure of the reactor is 1.0 kgf/cm.sup.2 higher than atmospheric pressure. Further, the temperature of the reactor was raised to 220° C. over 90 minutes, and maintained at 220° C. for 2 hours, and then, raised to 265° C. over 2 hours. And then, the mixture in the reactor was observed with the naked eye, and until the mixture became transparent, while maintaining the temperature of the reactor at 265° C., esterification was progressed for 245 minutes. During this process, by-products were discharged through the column and condenser. After the esterification was completed, nitrogen inside the reactor of a pressurized state was discharged outside to lower the pressure of the reactor to atmospheric pressure, and then, the mixture in the reactor was transferred to a reactor with a capacity of 7 L where a vacuum reaction can be progressed.

[0133] Step 2) Condensation Polymerization

[0134] The pressure of the reactor with a capacity of 7 L was lowered from atmospheric pressure state to 5 Torr (absolute pressure: 5 mmHg) over 30 minutes, and simultaneously, the temperature of the reactor was raised to 280° C. over 1 hour, and while maintaining the pressure of the reactor at 1 Torr (absolute pressure: 1 mmHg) or less, condensation polymerization was conducted. At the beginning of condensation polymerization, a stirring speed was set rapid, but if a stirring force decreases or the temperature of the reactant increases beyond a predetermined temperature due to viscosity increase of the reactant with the progression of condensation polymerization, the stirring speed may be appropriately controlled. The condensation polymerization was progressed until 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 a desired level, the mixture was discharged outside the reactor and stranded, and it was solidified with a coolant, and then, granulated such that the average weight became about 12 to 14 mg, thus preparing polyester copolymer.

Comparative Example 7

[0135] Step 1) Esterification

[0136] Into a reactor with a capacity of 10 L to which a column, and a condenser that can be cooled by water are connected, TPA (2576.1 g), EG (327.1 g), CHDM (1430.2 g), and ISB (951.6 g) were added, and GeO2 (13.4 g) as a catalyst, phosphoric acid (8.9 g) as a stabilizer, Polysynthren Blue RLS (Clarient, 0.021 g) as blue toner, Solvaperm Red BB (Clarient, 0.004 g) as red toner and high-density polyethylene (SK GeO centric YUZEX 2600S; 0.0041 g) as a crystallization agent were added.

[0137] Subsequently, nitrogen was added in the reactor to make a pressurized state where the pressure of the reactor is 0.5 kgf/cm.sup.2 higher than atmospheric pressure. Further, the temperature of the reactor was raised to 220° C. over 90 minutes, and maintained at 220° C. for 2 hours, and then, raised to 270° C. over 2 hours. And then, the mixture in the reactor was observed with the naked eye, and until the mixture became transparent, while maintaining the temperature of the reactor at 270° C., esterification was progressed for 245 minutes. During this process, by-products were discharged through the column and condenser. After the esterification was completed, nitrogen inside the reactor of a pressurized state was discharged outside to lower the pressure of the reactor to atmospheric pressure, and then, the mixture in the reactor was transferred to a reactor with a capacity of 7 L where a vacuum reaction can be progressed.

[0138] Step 2) Condensation Polymerization

[0139] The pressure of the reactor with a capacity of 7 L was lowered from atmospheric pressure state to 5 Torr (absolute pressure: 5 mmHg) over 30 minutes, and simultaneously, the temperature of the reactor was raised to 275° C. over 1 hour, and while maintaining the pressure of the reactor at 1 Torr (absolute pressure: 1 mmHg) or less, condensation polymerization was conducted. At the beginning of condensation polymerization, a stirring speed was set rapid, but if a stirring force decreases or the temperature of the reactant increases beyond a predetermined temperature due to viscosity increase of the reactant with the progression of condensation polymerization, the stirring speed may be appropriately controlled. The condensation polymerization was progressed until intrinsic viscosity (IV) of the mixture (molten material) in the reactor became 0.67 dl/g. If the intrinsic viscosity of the mixture in the reactor reached a desired level, the mixture was discharged outside the reactor and stranded, and it was solidified with a coolant, and then, granulated such that the average weight became about 12 to 14 mg, thus preparing polyester copolymer.

Comparative Example 8

[0140] Step 1) Esterification

[0141] Into a reactor with a capacity of 10 L to which a column, and a condenser that can be cooled by water, TPA (2598.8 g), EG (223.2 g), CHDM (1668.3 g), and ISB (182.9 g) were added, and GeO2 (13.1 g) as a catalyst, phosphoric acid (8.7 g) as a stabilizer, Polysynthren Blue RLS (Clarient, 0.024 g) as blue toner, and Solvaperm Red BB (Clarient, 0.004 g) as red toner were added.

[0142] Subsequently, nitrogen was added in the reactor to make a pressurized state where the pressure of the reactor is 1.0 kgf/cm.sup.2 higher than atmospheric pressure. Further, the temperature of the reactor was raised to 220° C. over 90 minutes, and maintained at 220° C. for 2 hours, and then, raised to 255° C. over 2 hours. And then, the mixture in the reactor was observed with the naked eye, and until the mixture became transparent, while maintaining the temperature of the reactor at 255° C., esterification was progressed for 245 minutes. During this process, by-products were discharged through the column and condenser. After the esterification was completed, nitrogen inside the reactor of a pressurized state was discharged outside to lower the pressure of the reactor to atmospheric pressure, and then, the mixture in the reactor was transferred to a reactor with a capacity of 7 L where a vacuum reaction can be progressed.

[0143] Step 2) Condensation Polymerization

[0144] The pressure of the reactor with a capacity of 7 L was lowered from atmospheric pressure state to 5 Torr (absolute pressure: 5 mmHg) over 30 minutes, and simultaneously, the temperature of the reactor was raised to 270° C. over 1 hour, and while maintaining the pressure of the reactor at 1 Torr (absolute pressure: 1 mmHg) or less, condensation polymerization was conducted. At the beginning of condensation polymerization, a stirring speed was set rapid, but if a stirring force decreases or the temperature of the reactant increases beyond a predetermined temperature due to viscosity increase of the reactant with the progression of condensation polymerization, the stirring speed may be appropriately controlled. The condensation polymerization was progressed until intrinsic viscosity (IV) of the mixture (molten material) in the reactor became 0.68 dl/g. If the intrinsic viscosity of the mixture in the reactor reached a desired level, the mixture was discharged outside the reactor and stranded, and it was solidified with a coolant, and then, granulated such that the average weight became about 12 to 14 mg.

[0145] The particles were left at 150° C. for 1 hour to crystallize, and then, added into a solid state polymerization reactor with a capacity of 20 L. And then, nitrogen was flowed into the reactor at a speed of 50 L/min. Wherein, the temperature of the reactor was raised from a room temperature to 140° C. at a speed of 40° C./hour, and maintained at 140° C. for 3 hours, and then, raised to 200° C. at a speed of and maintained at 200° C. The solid state polymerization was progressed until intrinsic viscosity (IV) of particles in the reactor became 1.0 dl/g, thus preparing polyester copolymer.

Comparative Example 9

[0146] Step 1) Esterification

[0147] Into a reactor with a capacity of 10 L to which a column, and a condenser that can be cooled by water are connected, TPA (2809.0 g), EG (430.2 g), CHDM (1583.9 g), and ISB (222.4 g) were added, and GeO2 (13.8 g) as a catalyst, phosphoric acid (9.1 g) as a stabilizer, Polysynthren Blue RLS (Clarient, 0.021 g) as blue toner, and Solvaperm Red BB (Clarient, 0.004 g) as red toner were added.

[0148] Subsequently, nitrogen was added in the reactor to make a pressurized state where the pressure of the reactor is 2.0 kgf/cm.sup.2 higher than atmospheric pressure. Further, the temperature of the reactor was raised to 220° C. over 90 minutes, and maintained at 220° C. for 2 hours, and then, raised to 260° C. over 2 hours. And then, the mixture in the reactor was observed with the naked eye, and until the mixture became transparent, while maintaining the temperature of the reactor at 260° C., esterification was progressed for 245 minutes. During this process, by-products were discharged through the column and condenser. After the esterification was completed, nitrogen inside the reactor of a pressurized state was discharged outside to lower the pressure of the reactor to atmospheric pressure, and then, the mixture in the reactor was transferred to a reactor with a capacity of 7 L where a vacuum reaction can be progressed.

[0149] Step 2) Condensation Polymerization

[0150] The pressure of the reactor with a capacity of 7 L was lowered from atmospheric pressure state to 5 Torr (absolute pressure: 5 mmHg) over 30 minutes, and simultaneously, the temperature of the reactor was raised to 270° C. over 1 hour, and while maintaining the pressure of the reactor at 1 Torr (absolute pressure: 1 mmHg) or less, condensation polymerization was conducted. At the beginning of condensation polymerization, a stirring speed was set rapid, but if a stirring force decreases or the temperature of the reactant increases beyond a predetermined temperature due to viscosity increase of the reactant with the progression of condensation polymerization, the stirring speed may be appropriately controlled. The condensation polymerization was progressed until 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 a desired level, the mixture was discharged outside the reactor and stranded, and it was solidified with a coolant, and then, granulated such that the average weight became about 12 to 14 mg, thus preparing polyester copolymer.

Comparative Example 10

[0151] Step 1) Esterification

[0152] Into a reactor with a capacity of 10 L to which a column, and a condenser that can be cooled by water are connected, TPA (2555.9 g), EG (305.5 g), CHDM (1330.3 g), and ISB (629.4 g) were added, and GeO2 (12.8 g) as a catalyst, phosphoric acid (8.5 g) as a stabilizer, Polysynthren Blue RLS (Clarient, 0.016 g) as blue toner, and Solvaperm Red BB (Clarient, 0.004 g) as red toner were added.

[0153] Subsequently, nitrogen was added in the reactor to make a pressurized state where the pressure of the reactor is 1.0 kgf/cm.sup.2 higher than atmospheric pressure. Further, the temperature of the reactor was raised to 220° C. over 90 minutes, and maintained at 220° C. for 2 hours, and then, raised to 250° C. over 2 hours. And then, the mixture in the reactor was observed with the naked eye, and until the mixture became transparent, while maintaining the temperature of the reactor at 250° C., esterification was progressed for 245 minutes. During this process, by-products were discharged through the column and condenser. After the esterification was completed, nitrogen inside the reactor of a pressurized state was discharged outside to lower the pressure of the reactor to atmospheric pressure, and then, the mixture in the reactor was transferred to a reactor with a capacity of 7 L where a vacuum reaction can be progressed.

[0154] Step 2) Condensation Polymerization

[0155] The pressure of the reactor with a capacity of 7 L was lowered from atmospheric pressure state to 5 Torr (absolute pressure: 5 mmHg) over 30 minutes, and simultaneously, the temperature of the reactor was raised to 275° C. over 1 hour, and while maintaining the pressure of the reactor at 1 Torr (absolute pressure: 1 mmHg) or less, condensation polymerization was conducted. At the beginning of condensation polymerization, a stirring speed was set rapid, but if a stirring force decreases or the temperature of the reactant increases beyond a predetermined temperature due to viscosity increase of the reactant with the progression of condensation polymerization, the stirring speed may be appropriately controlled. The condensation polymerization was progressed until 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 a desired level, the mixture was discharged outside the reactor and stranded, and it was solidified with a coolant, and then, granulated such that the average weight became about 12 to 14 mg, thus preparing polyester copolymer.

EXPERIMENTAL EXAMPLE

[0156] For the copolymers prepared in Examples and Comparative Examples, the properties were evaluated as follows. [0157] 1) Intrinsic viscosity: The polyester copolymer was dissolved in 150° C. orthohclorophenol (OCP) at the concentration of 0.12%, and then, intrinsic viscosity was measured using Ubbelohde viscometer in a 35° C. thermostat. [0158] 2) Storage modulus: The polyester copolymers prepared in Examples and Comparative Examples were made into specimens with a length of 17.5 mm, width of 13 mm, and thickness of 0.8 mm. The specimens were measured using Q800 equipment of TA Instruments, under conditions of temperature range of to 180° C., a temperature rise rate of 3° C./min, frequency of 1 Hz, and amplitude of 15 μm, in a single-cantilever mode, and a value measured at 40° C. was determined as storage modulus. [0159] 3) Melting point and heat of fusion: Using DSC1 equipment of Mettler toledo, melting point and heat of fusion were measured. Specifically, each polyester copolymer prepared in Examples and Comparative Examples was processed at a temperature of about 250 to 270° C. using injection molding machine to obtain an injection molded product of a flat plate specimen with a thickness of 6 mm, and then, for the polyester copolymer injection molded products, melting point and heat of fusion were measured at a temperature rise rate of +5° C./min, under nitrogen. [0160] 4) Glass transition temperature: Using Q800 equipment of TA Instruments, for each polyester copolymer prepared in Examples and Comparative Examples, glass transition temperature was measured at a temperature rise rate of 3° C./min, and a frequency of 10 Hz. [0161] 5) Melting point and heat of fusion: Using DSC1 equipment of Mettler toledo, for each polyester copolymer prepared in Examples and Comparative Examples, melting point and heat of fusion were measured at a temperature rise rate of +10° C./min, under nitrogen. [0162] 6) Measurement of draw ratio: Each polyester copolymer prepared in Examples and Comparative Examples was melt extruded at 290° C. to prepare a non-drawn film with a thickness of 300 μm. It was drawn in a machine direction at a temperature 30° C. higher than the glass transition temperature of each copolymer. Specifically, machine direction drawing was conducted at a rate of 750%/min, and it was evaluated whether or not drawing of 400% or more could be conducted.

[0163] The results were shown in the following Table 1.

TABLE-US-00001 TABLE 1 Glass Draw ratio Storage transition Melting Heat of of 400% IV modulus temperature point fusion or more Property Unit dl/g MPa ° C. ° C. J/g — factor.sup.1) Example 1 0.80 1900 90 232 5 ◯ 147.4 Example 2 0.65 1800 110 240 1 ◯ 825 Example 3 0.95 1830 100 250 16 ◯ 45.8 Example 4 1.0 1800 92 265 20 ◯ 31.2 Example 5 1.2 1900 100 237 10 ◯ 77.8 Example 6 1.1 2010 106 230 1 ◯ 926.3 Example 7 1.0 1930 100 235 12 ◯ 68.4 Example 8 1.2 1900 100 237 10 ◯ 77.8 Comparative 0.75 1900 95 — — ◯ — Example 1 Comparative 0.65 1750 97 — — X — Example 2 Comparative 0.95 1680 94 270 36 ◯ 16.2 Example 3 Comparative 1.0 1750 104 260 30 ◯ 23.3 Example 4 Comparative 0.98 1900 117 225 0.5 X 1976.0 Example 5 Comparative 0.70 1750 86 — — X — Example 6 Comparative 0.67 1680 118 — — X — Example 7 Comparative 1.0 1700 88 250 21 ◯ 28.5 Example 8 Comparative 0.72 1730 91 — — X — Example 9 Comparative 0.70 1650 104 — — X — Example 10 .sup.1)property factor = {(storage modulus)*(glass transition temperature)}/{(melting point)/(heat of fusion)}

[0164] In the Table 1, in the case of Comparative Examples 1, 2, 6, 7, 9 and since the polymers are non-crystalline, melting point and heat of fusion did not exist. Non-crystalline resin has lower storage modulus and drawing property compared to crystalline resin, and thus, has insufficient strength and moldability. Further, in the case of Comparative Example 5, heat of fusion is excessively low, meaning that it exhibits property similar to non-crystalline resin. Further, it can be confirmed that in the case of Comparative Example 8, glass transition temperature is excessively low, and thus, heat resistance is low. Meanwhile, it can be confirmed that in the case of Examples 1 to 8 according to the present disclosure, storage modulus is high and glass transition temperature is high, and thus, strength and heat resistance are excellent. Further, in the case of Examples 1 to 8 according to the present disclosure, melting point and heat of fusion are high, confirming that the polymers are crystalline.

[0165] Further, draw ratio of 400% or more means that polyester resin has high crystallinity, and polyesters according to the present disclosure all exhibited draw ratios of 400% or more, while in the case of Comparative Examples 2, 5, 6, 7, 9 and 10, due to low crystallinities, low drawing properties were exhibited.