COPOLYMERIZED POLYESTER RESIN, MOLDED PRODUCT, HEAT-SHRINKABLE FILM, AND FIBER

Abstract

The aim of the present invention is to provide a copolymerized polyester resin for solving the problem of die staining and foreign matter adhesion to the film etc. in the continuous production of the film etc.; and the problem of recycling property of the copolymerized polyester. This copolymerized polyester resin contains dicarboxylic acid and did as constituting components, wherein the copolymerized polyester resin contains terephthalic acid as a main component of a dicarboxylic acid component, and contains ethylene glycol as a main component of a diol component, wherein a content of diethylene glycol is from 7 to 30% by mole and a content of triethylene glycol is from 0.05 to 2% by mole when a total amount of the whole diol component is taken as 100% by mole, wherein a content of a cyclic dimer consisting of terephthalic acid and diethylene glycol is 7000 ppm or less, and wherein a content of a cyclic dimer consisting of terephthalic acid, diethylene glycol and triethylene glycol is 200 ppm or less.

Claims

1. A copolymerized polyester resin which contains dicarboxylic acid and diol as constituting components, wherein the copolymerized polyester resin contains terephthalic acid as a main component of a dicarboxylic acid component, and contains ethylene glycol as a main component of a diol component, wherein a content of diethylene glycol is from 7 to 30% by mole and a content of triethylene glycol is from 0.05 to 2% by mole when a total amount of the whole diol component is taken as 100% by mole, wherein a content of a cyclic dimer consisting of terephthalic acid and diethylene glycol is 7000 ppm or less, and wherein a content of a cyclic dimer consisting of terephthalic acid, diethylene glycol and triethylene glycol is 200 ppm or less.

2. The copolymerized polyester resin according to claim 1, wherein the copolymerized polyester resin has a color b value of from −5.0 to 10.0.

3. The copolymerized polyester resin according to claim 1, wherein the copolymerized polyester resin has a carboxyl end group concentration (AV) of from 8 to 25 eq/t, wherein the copolymerized polyester resin contains aluminum atom and phosphorus atom, wherein a content of the aluminum atom in the copolymerized polyester resin is 15 to 40 ppm, and wherein a molar ratio of the phosphorus atom to the aluminum atom in the copolymerized polyester resin is 1.8 to 2.6.

4. The copolymerized polyester resin according to claim 1, wherein, when a corrugated molded plate is prepared by molding the copolymerized polyester resin and a haze value is measured on an area of the corrugated molded plate having a thickness of 5 mm, the haze value is 10% or less.

5. A molded product, characterized in that, it contains the copolymerized polyester resin mentioned in claim 1.

6. A heat-shrinkable film, characterized in that, it contains the copolymerized polyester resin mentioned in claim 1.

7. A fiber, characterized in that, it contains the copolymerized polyester resin mentioned in claim 1.

Description

EXAMPLES

[0082] Hereunder, the present invention will be more specifically illustrated by Examples although the present invention shall not be limited thereto. The characteristic features of the copolymerized polyester resin wore measured by the following methods.

[0083] 1) Number-Average Molecular Weight

[0084] Number-average molecular weight was measured by Waters gel permeation chromatography using a mixed solvent of chloroform/hexafluoroisopropanol (ratio by volume=9/1) as a solvent and polystyrene as a calibration reference. The measured value converted in terms of polystyrene was obtained using a mixed solvent of chloroform/hexafluoroisopropanol (ratio by volume=9/1) as an eluting solution.

[0085] 2) Intrinsic Viscosity (IV) of the Copolymerized Polyester Resin

[0086] A sample (0.1 g) being dried at 60° C. for 24 hours was precisely weighed and dissolved in a mixed solvent of 25 mL of phenol/tetrachloroethane (in a ratio of 3/2 by mass). Its intrinsic viscosity was measured at 30° C. using an Ostwald viscometer.

[0087] 3) Content of T2D2

[0088] A copolymerized polyester resin (30 mg) was dissolved in 1 mL of a mixed liquid of hexafluoroisopropanol/chloroform (ratio by volume=1/9) followed by further diluting by addition of 4 mL of chloroform. Then, 10 mL of methanol was added thereto so as to precipitate the polymer. After that, centrifugal separation was conducted. A supernatant liquid after the centrifugal separation was concentrated and evaporated to dryness followed by re-dissolving in 0.4 mL of dimethylformamide so as to prepare a solution. This solution was used to determine the content of T2D2 by high-performance liquid chromatography.

[0089] Apparatus: Waters ACQUITY UPLC

[0090] Column: Waters BEH-C16 2.1×150 mm (manufactured by Waters)

[0091] 4) Content of T2D1TE1

[0092] Content of T2D1TE1 was measured by high-performance liquid chromatography in the same method as for the above measurement of the T2D2 content.

[0093] 5) Composition Ratio of the Copolymerizod Polyester Resin

[0094] A sample of the copolymerized polyester resin (about 5 mg) was dissolved in 0.7 ml of a mixed solution of chloroform-d and trifluoroacetic acid (ratio by volume: 9/1). Composition ratio was determined using .sup.1H-NMR (UNITY 50 manufactured by Varian).

[0095] 6) Color Tone

[0096] Color of chips of the copolymerized polyester resin was measured using a colorimeter (ZE-6000 manufactured by Nippon Denshoku) so as to determine the color b value.

[0097] 7) Haze Value

[0098] The copolymerized polyester resin was melted at 280° C. using an injection molding device (M-150C-DM manufactured by Meiki Seisakusho) and molded into a corrugated molded plate having a thickness of 2 to 11 mm at a mold temperature of 10° C. Haze value (%) was measured on an area of the corrugated molded plate having a thickness of 5 mm by a haze-meter (Model NDH2000 manufactured by Nippon Denshoru).

[0099] 8) Moldability Test (Evaluation of Sheet-Preparation Property)

[0100] A dried copolymerized polyester resin sample was placed into an extruder equipped with die for sheet, and sheets of about 0.5 mm thickness were continuously molded for two days. A state of adhesion of staining material on the die outlet and a state of the sheet surface were evaluated by naked eyes according to the following criteria.

[0101] (Evaluation Criteria)

[0102] oo: Almost no staining material was adhered on the die outlet and the surface state of the sheet was good.

[0103] O: Although the staining material was very slightly adhered on the die outlet, the surface state of the sheet was good.

[0104] Δ: The staining material was slightly adhered on the die outlet and foreign matter was slightly adhered on the sheet surface.

[0105] x: The staining material was significantly adhered on the die outlet and the foreign matter was significantly adhered on the sheet surface.

[0106] 9) DSC Measurement of the Copolymerized Polyester Resin

[0107] A sample was allowed to stand in a Yamato DP63 drier at 120° C. for 120 minutes. Then, this sample was heated at a rate of 20° C./min from −100° C. to 300° C., then cooled at a rate of 50° C./min down to −100° C., and then heated at a rate of 20° C./min from −100° C. to 300° C., using a differential scanning calorimeter (DSC). It was checked whether there were melting peaks during the two heating processes. When there was no melting peak in any of the two heating processes, the sample was judged as “o”. When there was a melting peak in at least one of the processes, the sample was judged as “x”.

[0108] 10) Evaluation of Thermal Stability: Parameter of Thermal Oxidative Decomposition (TD)

[0109] Dried chips (3 g) of the copolymerized polyester resin were placed in a test tube made of glass, and melted by being immersed in an oil bath of 280° C. for 120 minutes under a nitrogen atmosphere. TD was determined according to the following formulae.

[0110] [IV].sub.f1 after heating was measured. TD was determined as follows. Here, [IV].sub.1 and [IV].sub.f1 stand for IV (dL/g) before and after the heating test, respectively.

TD=0.245 {[IV].sub.f1.sup.−1.47−[IV].sub.i.sup.−1.47}

[0111] When the value of the parameter of thermal oxidative decomposition (TD) of the copolymerized polyester is small, the thermal stability is high.

Example 1

[0112] A slurry containing high purity terephthalic acid (TPA) as a dicarboxylic acid component and ethylene glycol (EG), diethylene glycol (DEG) and triethylene glycol (TEG) as glycol components was prepared with a molar ratio (G/A) of the total glycol components to the dicarboxylic component of 2.2. This slurry was continuously supplied to a first esterification reactor wherein a reacting product remains. After that, an esterification reaction was conducted with stirring under a condition wherein the pressure in the reactor was 0.15 MPa and the temperature was 257° C. so as to make the average retention time 3 hours. The resulting reaction product was transferred to a second esterification reactor, and an esterification reaction was conducted with stirring under a condition wherein the pressure in the reactor was 0.05 MPa and the temperature was 257° C. so as to make the average retention time 1 hour. The resulting esterification reaction product was transferred to a third esterification reactor, and an esterification reaction was conducted with stirring under a condition wherein the pressure in the reactor was 0.05 MPa and the temperature was 257° C.

[0113] To the resulting oligomer, diethylene glycol was added in an amount corresponding to 20% of the amount which was added before the esterification reaction, so as to achieve the aimed composition. Then, the resulting mixture was stirred for 15 minutes, so as to conduct the reaction.

[0114] Then, predetermined amounts of a solution of an aluminum compound (basic aluminum acetate) in ethylene glycol and a solution of a phosphorus compound (Irganox 1222: a compound of the above-mentioned chemical formula (4)) in ethylene glycol were added to this esterification reaction product. The resulting mixture was continuously supplied to the first polycondensation reactor, and a polycondensation reaction was conducted with stirring at 261° C. and 6.7 kPa for 1 hour; then, at 272° C. and 0.6 kPa for 1 hour with stirring in the second polycondensation reactor; and then, at 275° C. and 0.10 to 0.20 kPa for 1 hour with stirring in the final polycondensation reactor. After the polycondensation reaction, the reaction product was passed through a polymer filter, and the copolymerized polyester resin in a melted state was pulled out in a strand form from a nozzle of a die, cooled with water in a cooling bath, and cut into chips. The number-average molecular weight of the resulting copolymerized polyester resin was 19,000.

[0115] Result of the evaluations is shown in Table 1. The copolymerized polyester resin obtained in this Example was evaluated in view of sheet moldability by the method mentioned in 8). The moldability was good.

Example 2

[0116] A slurry containing highly pure cerephthalic acid (TPA) as a dicarboxylic acid component and ethylene glycol (EG) and diethylene glycol as glycol components was prepared with a molar ratio (G/A) of the total glycol components to the dicarboxylic component of 2.2. This slurry was continuously supplied to a first esterification reactor wherein the reacting substances previously remain. After chat, an esterification reaction was conducted with stirring under a condition wherein the pressure in the reactor was 0.15 MPa and the temperature was 257° C. so as to make the average retention time 3 hours. The resulting reaction product was transferred to a second esterification reactor, and an esterification reaction was conducted with stirring under a condition wherein the pressure in the reactor was 0.05 MPa and the temperature was 257° C. so as to make the average retention time 1 hour. The resulting esterification reaction product was transferred to a third esterification reactor, and an esterification reaction was conducted with stirring under a condition wherein the pressure in the reactor was 0.05 MPa and the temperature was 257° C.

[0117] To the resulting oligomer, diethylene glycol was added in an amount corresponding to 20% of the amount which was added before the esterification reaction, so as to achieve the aimed composition. Then, the resulting mixture was stirred for 15 minutes, so as to conduct the reaction.

[0118] Then, predetermined amounts of a solution of an aluminum compound (basic aluminum acetate) in ethylene glycol and a solution of a phosphorus compound (Irganox 1222: a compound of the above-mentioned chemical formula (4)) in ethylene glycol were added to this esterification reaction product. The resulting mixture was continuously supplied to the first polycondensation reactor, and a polycondensation reaction was conducted with stirring at 261° C. and 6.7 kPa for 1 hour; then, at 272° C. and 0.6 kPa for 1 hour with stirring in the second polycondensation reactor; and then, at 275° C. and 0.10 to 0.20 kPa for 1 hour with stirring in the final polycondensation reactor. After the polycondensation reaction, the reaction product was passed through a polymer filter, and the copolymerized polyester resin in a melted state was pulled out in a strand form from a nozzle of a die, cooled with water in a cooling bath, and cut into chips. The number-average molecular weight of the resulting copolymerized polyester resin was 20,000.

[0119] Result of the evaluations is shown in Table 1. The copolymerized polyester resin obtained in this Example was evaluated in view of sheet moldability by the method mentioned in 8). The moldability was good.

Examples 3 to 5

[0120] Copolymerized polyester resins were obtained in the same manner as in Example 2. Result of the evaluations is shown in Table 1. The copolymerized polyester resins obtained in these Examples were evaluated in view of sheet moldability by the method mentioned in 8). The moldability was good.

Example 6

[0121] A slurry containing highly pure terephthalic acid (TPA) as a dicarboxylic acid component, and ethylene glycol (EG) and diethylene glycol (DEG) as glycol components was prepared with a molar ratio (G/A) of the total glycol components to the dicarboxylic component of 1.6. This slurry was continuously supplied to a first esterification reactor wherein the reacting substances previously remain. After that, an esterification reaction was conducted with stirring under a condition wherein the pressure in the reactor was 0.15 MPa and the temperature was 257° C. so as to make the average retention time 3 hours. The resulting reaction product was transferred to a second esterification reactor, and an esterification reaction was conducted with stirring under a condition wherein the pressure in the reactor was 0.05 MPa and the temperature was 257° C. so as to make the average retention time 1 hour. The resulting esterification reaction product was transferred to a third esterification reactor, and an esterification reaction was conducted with stirring under a condition wherein the pressure in the reactor was 0.05 MPa and the temperature was 257° C.

[0122] To the resulting oligomer, diethylene glycol was added in an amount corresponding to 20% of the amount which was added before the esterification reaction, so as to achieve the aimed composition. Then, the resulting mixture was stirred for 15 minutes, so as to conduct the reaction.

[0123] Then, predetermined amounts of a solution of an aluminum compound (basic aluminum acetate) in ethylene glycol and a solution of a phosphorus compound (Irganox 1222: a compound of the above-mentioned chemical formula (4)) in ethylene glycol were added to this esterification reaction product. The resulting mixture was continuously supplied to the first polycondensation reactor, and a polycondensation reaction was conducted with stirring at 261° C. and 6.7 kPa for 1 hour; then, at 272° C. and 0.6 kPa for 1 hour with stirring in the second polycondensation reactor; and then, at 275° C. and 0.10 to 0.20 kPa for 1 hour with stirring in the final polycondensation reactor. After the polycondensation reaction, the reaction product was passed through a polymer filter, and the copolymerized polyester resin in a melted state was pulled out in a strand form from a nozzle of a die, cooled with water in a cooling bath, and cut into chips. The number-average molecular weight of the resulting copolymerized polyester resin was 20,000. The carboxyl end group concentration of the resulting copolymerized polyester resin was 24 eq/t. Result of the evaluations is shown in Table 1. The copolymerized polyester resin obtained in this Example was evaluated in view of sheet moldability by the method mentioned in 8). The moldability was good. The resin color was 4.5, and the evaluation of thermal stability was 0.10. Therefore, the resin color and the evaluation of thermal stability were slightly lowered.

Example 7

[0124] Terephthalic acid (TPA) (2414 parts by mass), ethylene glycol (EG) and diethylene glycol (DEG) were placed in an esterification reactor of 10 L volume equipped with a stirrer and a distillation condenser. Then, a solution of antimony trioxide and cobalt acetate as a catalyst in ethylene glycol was added thereto in such an amount that the resulting copolymerized polymer resin contains 250 ppm of antimony metal and 10 ppm of cobalt metal.

[0125] After that, the reaction system was gradually heated up to the final temperature of 240° C., and an esterification reaction was conducted for 180 minutes at the pressure of 0.25 MPa. After it was confirmed that no more distilled water came from the reaction system, the reaction system was returned to the ordinary pressure. To the resulting oligomer, diethylene glycol was added in an amount corresponding to 20% of the amount which was added before the esterification reaction, so as to achieve the aimed composition. Then, the resulting mixture was stirred for 15 minutes, so as to conduct the reaction. A solution of trimethyl phosphate in ethylene glycol was added thereto in such an amount that the resulting copolymerized polyester contains 50 ppm of the residual phosphorus atom.

[0126] The resulting oligomer was transferred to a polycondensation rector and the pressure was reduced together with gradual temperature rise so that the final temperature and pressure become 270° C. and 0.2 hPa, respectively. The reaction was continued until a torque value of a stirring blade corresponding to the intrinsic viscosity reached a desired value, and then the polycondensation reaction was finished. The resulting melted copolymerized polyester resin was pulled out in a strand from a pulling-out hole at a lower part of the polycondensation reactor, cooled with a water bath tank and cut into chips. The number-average molecular weight of the resulting copolymerized polymer resin was 19000. The resulting copolymerized polyester resin was subjected to a heating treatment in the same manner as in Example 1.

[0127] Result is shown in Table 1. The copolymerized polyester resin obtained in this Example was evaluated in view of sheet moldability by the method mentioned in 8). The moldability was good. There was a tendency that the haze of the corrugated molded plate and the thermal stability were a bit inferior. However, there was no problem.

Examples 8 and 9

[0128] Copolymerized polyester resins were obtained in the same manner as in Example 2. Result of the evaluations is shown in Table 1. The copolymerized polyester resins obtained in these Examples were evaluated in view of sheet moldability by the method mentioned in 8). The moldability was good. There was a tendency that the haze of the corrugated molded plate was a bit inferior. However, there was no problem.

Example 10

[0129] A slurry containing highly pure terephthalic acid (TPA) as a dicarboxylic acid component and ethylene glycol (EG) and diethylene glycol (DEG) as glycol components was prepared with a molar ratio (G/A) of the total glycol components to the dicarboxylic component of 2.2. This slurry was continuously supplied to a first esterification reactor wherein the reacting substances previously remain. After that, an esterification reaction was conducted with stirring under a condition wherein the pressure in the reactor was 0.15 MPa and the temperature was 257° C. so as to make the average retention time 4 hours. The resulting reaction product was transferred to a second esterification reactor, and an esterification reaction was conducted with stirring under a condition wherein the pressure in the reactor was 0.05 MPa and the temperature was 257° C. so as to make the average retention time 2 hours. The resulting esterification reaction product was transferred to a third esterification reactor, and an esterification reaction was conducted with stirring under a condition wherein the pressure in the reactor was 0.05 MPa and the temperature was 257° C.

[0130] To the resulting oligomer, diethylene glycol was added in an amount corresponding to 20% of the amount which was added before the esterification reaction, so as to achieve the aimed composition. Then, the resulting mixture was stirred for 15 minutes, so as to conduct the reaction.

[0131] Then, predetermined amounts of a solution of an aluminum compound (basic aluminum acetate) in ethylene glycol and a solution of a phosphorus compound (Irganox 1222: a compound of the above-mentioned chemical formula (4)) in ethylene glycol were added to this esterification reaction product. The resulting mixture was continuously supplied to the first polycondensation reactor, and a polycondensation reaction was conducted with stirring at 261° C. and 6.7 kPa for 1 hour; then, at 272° C. and 0.6 kPa for 1 hour with stirring in the second polycondensation reactor; and then, at 275° C. and 0.10 to 0.20 kPa for 1 hour with stirring in the final polycondensation reactor. After the polycondensation reaction, the reaction product was passed through a polymer filter, and the copolymerized polyester resin in a melted state was pulled out in a strand form from a nozzle of a die, cooled with water in a cooling bath, and cut into chips. The number-average molecular weight of the resulting copolymerized polyester resin was 19,000.

[0132] Result of the evaluations is shown in Table 1. The copolymerized polyester resin obtained in this Example was evaluated in view of sheet moldability by the method mentioned in 8). The moldability was good.

Example 11

[0133] A slurry containing highly pure terephthalic acid (TPA) as a dicarboxylic acid component and ethylene glycol (EG) and diethylene glycol (DEC) as glycol components was prepared with a molar ratio (G/A) of the total glycol components to the dicarboxylic component of 2.2. This slurry was continuously supplied to a first esterification reactor wherein the reacting substances previously remain. After that, an esterification reaction was conducted with stirring under a condition wherein the pressure in the reactor was 0.15 MPa and the temperature was 257° C. so as to make the average retention time 2.5 hours. The resulting reaction product was transferred to a second esterification reactor, and an esterification reaction was conducted with stirring under a condition wherein the pressure in the reactor was 0.05 MPa and the temperature was 257° C. so as to make the average retention time 0.8 hour. The resulting esterification reaction product was transferred to a third esterification reactor, and an esterification reaction was conducted with stirring under a condition wherein the pressure in the reactor was 0.05 MPa and the temperature was 257° C.

[0134] To the resulting oligomer, diethylene glycol was added in an amount corresponding to 20% of the amount which was added before the esterification reaction, so as to achieve the aimed composition. Then, the resulting mixture was stirred for 15 minutes, so as to conduct the reaction.

[0135] Then, predetermined amounts of a solution of an aluminum compound (basic aluminum acetate) in ethylene glycol and a solution of a phosphorus compound (Irganox 1222: a compound of the above-mentioned chemical formula (4)) in ethylene glycol were added to this esterification reaction product. The resulting mixture was continuously supplied to the first polycondensation reactor, and a polycondensation reaction was conducted with stirring at 261° C. and 6.7 kPa for 1 hour; then, at 272° C. and 0.6 kPa for 1 hour with stirring in the second polycondensation reactor; and then, at 275° C. and 0.10 to 0.20 kPa for 1 hour with stirring in the final polycondensation reactor. After the polycondensation reaction, the reaction product was passed through a polymer filter, and the copolymerized polyester resin in a melted state was pulled out in a strand form from a nozzle of a die, cooled with water in a cooling bath, and cut into chips. The number-average molecular weight of the resulting copolymerized polyester resin was 19,000.

[0136] Result of the evaluations is shown in Table 1. The copolymerized polyester resin obtained in this Example was evaluated in view of sheet moldability by the method mentioned in 8). The moldability was good. There was a tendency that the color tone, the haze of the corrugated molded plate and the thermal stability were a bit inferior. However, there was no problem.

Comparative Example 1

[0137] A slurry containing highly pure terephthalic acid (TPA) as a dicarboxylic acid component and ethylene glycol (EG) as a glycol component was prepared with a molar ratio (G/A) of the total glycol components to the dicarboxylic component of 2.0. This slurry was continuously supplied to a first esterification reactor wherein the reacting substances previously remain. After that, an esterification reaction was conducted with stirring under a condition wherein the pressure in the reactor was 0.17 MPa and the temperature was 255° C. so as to make the average retention time 3 hours. The resulting reaction product was transferred to a second esterification reactor, and an esterification reaction was conducted with stirring under a condition wherein the pressure in the reactor was 0.05 MPa and the temperature was 261° C. so as to make the average retention time 1 hour. The resulting esterification reaction product was transferred to a third esterification reactor, and an esterification reaction was conducted with stirring under a condition wherein the pressure in the reactor was 0.05 MPa and the temperature was 266 to 267° C. Then, predetermined amounts of a solution of an aluminum compound (basic aluminum acetate) in ethylene glycol and a solution of a phosphorus compound (Irganox 1222: a compound of the above-mentioned chemical formula (4)) in ethylene glycol were added to this esterification reaction product. The resulting mixture was continuously supplied to the first polycondensation reactor, and a polycondensation reaction was conducted with stirring at 268° C. and 4.7 kPa for 1 hour; then, at 270° C. and 0.57 kPa for 1 hour with stirring in the second polycondensation reactor; and then, at 274° C. and 0.17 kPa for 1 hour with stirring in the final polycondensation reactor. After the polycondensation reaction, the reaction product was passed through a polymer filter, and the copolymerized polyester resin in a melted state was pulled out in a strand form from a nozzle of a die, cooled with water in a cooling bath, and cut into chips. The number-average molecular weight of the resulting copolymerized polyester resin was 19,000. Result of the evaluations is shown in Table 1. The content of cyclic oligomer was not measured.

Comparative Example 2

[0138] A copolymerized polyester resin was synthesized using the same synthesis method as in Example 2 except that the amount of DEG was adjusted to 5% by mole. The resulting copolymerized polyester resin was evaluated. Since this copolymerized polyester resin contains little DEG, it was inferior in any of the evaluations. Result of the evaluations is shown in Table 1.

Comparative Example 3

[0139] A copolymerized polyester resin was synthesized using the same synthesis method as in Example 2 except that the amount of DEG was adjusted to 34% by mole. The resulting copolymerized polyester resin was evaluated. Since this copolymerized polyester resin contains abundant DEG, it was inferior in evaluation of sheet-preparation property and thermal stability Result of the evaluations is shown in Table 1.

Comparative Example 4

[0140] A copolymerized polyester resin was synthesized using the same synthesis method as in Example 2 except that the amount of DEG was adjusted to 19% by mole and the amount of TEG was adjusted to 2.5% by mole. The resulting copolymerized polyester resin was evaluated. Since this copolymerized polyester resin contains abundant TEG, it was inferior in any of the evaluations. Result of the evaluations is shown in Table 1.

Comparative Example 5

[0141] A slurry containing highly pure terephthalic acid (TPA) as a dicarboxylic acid component and ethylene glycol (EG) and diethylene glycol as glycol components was prepared with a molar ratio (G/A) of the total glycol components to the dicarboxylic component of 2.2. This slurry was continuously supplied to a first esterification reactor wherein the reacting substances previously remain. After that, an esterification reaction was conducted with stirring under a condition wherein the pressure in the reactor was 0.15 MPa and the temperature was 257° C. so as to make the average retention time 3 hours. The resulting reaction product was transferred to a second esterification reactor, and an esterification reaction was conducted with stirring under a condition wherein the pressure in the reactor was 0.05 MPa arid the temperature was 257° C. so as to make the average retention time 1 hour. The resulting esterification reaction product was transferred to a third esterification reactor, and an esterification reaction was conducted with stirring under a condition wherein the pressure in the reactor was 0.05 MPa and the temperature was 257° C.

[0142] Then, predetermined amounts of a solution of an aluminum compound (basic aluminum acetate) in ethylene, glycol and a solution of a phosphorus compound (Irganox 1222: a compound of the above-mentioned chemical formula (4)) in ethylene glycol were added to this esterification reaction product. The resulting mixture was continuously supplied to the first polycondensation reactor, and a polycondensation reaction was conducted with stirring at 261° C. and 6.7 kPa for 1 hour; then, at 272° C. and 0.6 kPa for 1 hour with stirring in the second polycondensation reactor; and then, at 275° C. and 0.10 to 0.20 kPa for 1 hour with stirring in the final polycondensation reactor. After the polycondensation reaction, the reaction product was passed through a polymer filter, and the copolymerized polyester resin in a melted state was pulled out in a strand form from a nozzle of a die, cooled with water in a cooling bath, and cut into chips. The number-average molecular weight of the resulting copolymerized polyester resin was 20,000. Since this copolymerized polyester resin contains abundant T2D1TE1 and T2D2, it was inferior in evaluation of sheet-preparation property and haze. Result of the evaluations is shown in Table 1.

TABLE-US-00001 TABLE 1 Items Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Example 9 Compositions terephthalic acid 100 100 100 100 100 100 100 100 100 of resins ethylene glycol 80.9 82.5 79.3 70.1 82.8 91.2 77.8 82.5 82.5 (mol %) diethylene glycol 18.0 17.0 20.0 29.0 17.0 8.2 21.0 17.0 17.0 triethylene glycol 1.1 0.5 0.7 0.9 0.2 0.6 1.2 0.5 0.5 Cyclic T2D2 5300 4800 5900 4900 3200 4000 5800 4600 5100 oligomer T2D1TE1 98 43 98 123 21 52 76 43 80 Physical number-average 20000 19000 18000 19000 19900 20000 19000 19000 19000 properties molecular weight of resins carboxyl end group 16 12 12 14 8 24 12 12 12 concentration (AV) (eq/t) color b value 2.3 2.2 3.0 3.0 2.3 4.5 2.3 2.2 2.2 Tg (° C.) 56 59 56 52 59 64 56 59 59 Amount of aluminum 30 30 30 30 30 35 — 45 10 remaining phosphorus 77 77 77 87 65 90 50 120 20 metal (ppm) antimony — — — — — — 250 cobalt — — — — — — 10 molar ratio of 2.2 2.2 2.2 2.5 1.9 2.2 — 2.3 1.7 phosphorus atom to aluminum atom Evaluation of sheet-preparation ∘ ∘∘ ∘ ∘∘ ∘ ∘∘ ∘∘ ∘ ∘ property Haze of corrugated molded plate (%) 4.3 4.4 1.5 4.3 1.0 4.8 9.8 9.5 4.5 DSC measurement ∘ ∘ ∘ ∘ ∘ ∘ ∘ ∘ ∘ Thermal TD 0.04 0.04 0.06 0.06 0.09 0.10 0.12 0.02 0.05 stability Comparative Comparative Comparative Comparative Comparative Items Example 10 Example 11 Example 1 Example 2 Example 3 Example 4 Example 5 Compositions terephthalic acid 100 100 100 100 100 100 100 of resins ethylene glycol 82.5 82.5 99.05 94.4 64.8 78.5 79.6 (mol %) diethylene glycol 17.0 17.0 0.90 5.0 34.0 19.0 20.0 triethylene glycol 0.5 0.5 0.05 0.6 1.2 2.5 0.4 Cyclic T2D2 4500 4200 — 6800 7700 7800 7200 oligomer T2D1TE1 30 43 — 180 230 250 210 Physical number-average 19000 19000 19000 19000 19000 19000 18000 properties molecular weight of resins carboxyl end group 3 30 12 15 19 10 12 concentration (AV) (eq/t) color b value 1.5 9.5 1.9 3.3 10.2 3.9 3.0 Tg (° C.) 58 59 78 72 48 58 56 Amount of aluminum 30 30 30 30 30 30 30 remaining phosphorus 77 77 77 77 77 77 77 metal (ppm) antimony — — — — — cobalt — — — — — molar ratio of 2.2 2.2 2.2 2.2 2.2 2.2 2.2 phosphorus atom to aluminum atom Evaluation of sheet-preparation ∘ ∘ x x x x x property Haze of corrugated molded plate (%) 4.5 9.9 30.0 16.0 4.6 16.5 10.1 DSC measurement ∘ ∘ x x ∘ ∘ ∘ Thermal TD 0.03 0.15 0.01 0.11 0.19 0.15 0.07 stability

INDUSTRIAL APPLICABILITY

[0143] The copolymerized polyester resin of the present invention is excellent in terms of transparency, color tone and moldability and, further, exhibits less stain of the molding die and less foreign matter adhesion to the molded product and film. Accordingly, the copolymerized polyester resin of the present, invention is excellent in economic efficiency and can give a molded product having high commercial value whereby it greatly contributes in industrial world.