KR20230028875A - Polyester copolymer and molded article comprising the same - Google Patents

Abstract

The present invention relates to a polyester copolymer having more improved heat resistance and moisture stability and excellent chromaticity, and a molded article including the same. The polyester copolymer includes: a dicarboxylic acid component residue including a terephthalic acid; and a diol component residue including isocarbide, cyclohexanedimethanol, and a diol having a fluorene ring, wherein the diol residue having a fluorene ring is included in a certain amount.

Description

Polyester copolymer and molded article comprising the same {Polyester copolymer and molded article comprising the same}

The present invention relates to a polyester copolymer having more improved heat resistance and moisture stability and excellent chromaticity, and a molded article including the same.

Since polyester has excellent mechanical strength, heat resistance, transparency, and gas barrier properties, it is widely used as various materials such as containers for filling various foods or beverages, packaging materials such as packaging films, various medical devices, or films for audio and video. there is.

Among them, polyester is widely used in the manufacture of containers for food or beverages, various medical devices, etc. In the case of such containers or medical devices, they are subject to high-temperature heat or large amounts of moisture for heating or disinfection in the process of use. are often exposed. For this reason, excellent heat resistance and water stability are required for polyesters used in the production of these molded articles.

In particular, since polyesters based on terephthalic acid and ethylene glycol, which are most widely used, are very vulnerable to high-temperature heat or moisture, in the production of these polyesters, various aliphatic or aromatic cyclic diols have been added to , Various attempts have been made to improve the heat resistance and moisture stability of the polyester.

As a representative example of such a heat-resistant polyester, a polyester prepared by additionally using isocarbide as a diol has been developed and used. When using such a child carbide, since it is possible to manufacture a polyester having high crystallinity and intrinsic viscosity, it is known to improve the heat resistance of the polyester.

However, such conventional heat-resistant polyesters may absorb a large amount of moisture due to the nucleophilicity and hydrogen bonding of isosorbide, particularly when exposed to high temperatures, and as a result, have a disadvantage in that moisture stability is not sufficient. In addition, due to the high crystallinity of the isosorbide, the conventional heat-resistant polyester often has an increased yellowness and haze, thereby degrading the quality of molded products.

Due to the problems of these existing heat-resistant polyesters, various attempts have been made to develop polyesters exhibiting improved heat resistance, excellent moisture stability, low yellowness and haze, etc. Polyester is not properly developed.

Accordingly, there is a continuous demand for development of heat-resistant polyesters exhibiting improved heat resistance, moisture stability, and low yellowness.

Accordingly, the present invention is to provide a polyester copolymer having more improved heat resistance and moisture stability, and excellent chromaticity, and a molded product including the same.

Accordingly, the present invention is a residue of a dicarboxylic acid component including terephthalic acid; and

Residues of diol components including isocarbide, cyclohexanedimethanol and diols having a fluorene ring;

Based on 100 mol% of the residues of the dicarboxylic acid component, the residue of the diol having a fluorene ring is included in an amount of 1 to 15 mol% to provide a polyester copolymer.

The present invention also provides a molded article comprising the polyester copolymer.

Hereinafter, polyester copolymers and molded articles according to specific embodiments of the invention will be described in more detail. First, in the following, some terms may be defined as follows.

First, unless otherwise specified in the present specification, terminology is only used to refer to a specific embodiment and is not intended to limit the invention. And, unless the meaning is clearly stated to the contrary, singular forms include plural forms. As used herein, the meaning of 'comprising' specifies specific characteristics, domains, integers, steps, operations, elements and/or components, and includes other specific characteristics, domains, integers, steps, operations, elements, components and/or groups. It does not exclude existence or addition.

In addition, in this specification, 'residue (of a certain component such as dicarboxylic acid or diol)' is included in the product of a chemical reaction when a specific component (compound) participates in a chemical reaction and is derived from the specific component. Means a certain part or unit. Specifically, each of the 'residue' of the dicarboxylic acid component or the 'residue' of the diol component is a portion derived from the dicarboxylic acid component or a diol component in a polyester copolymer formed by esterification or condensation polymerization. refers to the part derived from

On the other hand, the polyester copolymer according to one embodiment of the invention is a residue of a dicarboxylic acid component including terephthalic acid; and residues of a diol component including isocarbide, cyclohexanedimethanol, and a diol having a fluorene ring;

1 to 15 mol%, or 3 to 15 mol%, or 3 to 10 mol%, or 5 to 10 mol% of the residues of the diol having a fluorene ring, based on 100 mol% of the residues of the dicarboxylic acid component It is included in the amount of mol%.

The polyester copolymer of this embodiment is basically prepared by using isocarbide, which has been used in conventional heat-resistant polyester, as a diol component. Accordingly, the polyester copolymer of one embodiment may exhibit excellent heat resistance.

In addition, the present inventors continued research using various diol components to improve the high hygroscopicity, poor water stability, chromaticity and haze of the isocarbide-derived polyester. As a result of such continuous research, as a polyester is prepared using cyclohexanedimethanol and a diol having a fluorene ring, water stability, chromaticity and haze of the polyester are improved, while mechanical properties can be improved together. found out and completed the invention.

In particular, when the diol having a fluorene ring is additionally used in a predetermined amount, it is possible to improve moisture stability by lowering the hygroscopicity of polyester, and to solve the disadvantages caused by the crystallinity of isocarbide, thereby improving the yellowness and It was confirmed that the generation of haze can be lowered. However, if the residue content of the diol having a fluorene ring is too low, the improvement in water stability and chromaticity of the polyester copolymer is not sufficient, and if the content is too high, the impact strength of the polyester copolymer mechanical properties may deteriorate.

In addition, as the polyester copolymer of one embodiment further includes a residue of cyclohexanedimethanol, mechanical properties such as impact strength may be further improved.

As described above, the polyester copolymer of one embodiment contains a residue of a predetermined diol component, thereby solving the problems of existing heat-resistant polyesters and simultaneously satisfying excellent heat resistance, moisture stability, chromaticity and low haze, It can be used very preferably in the manufacture of food containers or medical devices requiring heat resistance.

Hereinafter, a polyester copolymer of one embodiment and a manufacturing method thereof will be described in more detail.

dicarboxylic acid component

In the copolymer of one embodiment, the dicarboxylic acid component means a main monomer constituting the polyester copolymer together with the diol component. In particular, the dicarboxylic acid includes terephthalic acid, and physical properties such as heat resistance, chemical resistance, and weather resistance of the polyester copolymer may be improved by terephthalic acid.

The dicarboxylic acid component may further include an aromatic dicarboxylic acid component, an aliphatic dicarboxylic acid component, or a mixture thereof in addition to terephthalic acid. In this case, dicarboxylic acid components other than terephthalic acid are preferably included in an amount of 30% by weight or less, or 1 to 30% by weight based on the total weight of all dicarboxylic acid components.

The aromatic dicarboxylic acid component may be an aromatic dicarboxylic acid having 8 to 20 carbon atoms, preferably 8 to 14 carbon atoms, or a mixture thereof. Examples of the aromatic dicarboxylic acid include naphthalene dicarboxylic acids such as isophthalic acid and 2,6-naphthalenedicarboxylic acid, diphenyl dicarboxylic acid, 4,4'-stilbendicarboxylic acid, 2, 5-furandicarboxylic acid, 2,5-thiophenedicarboxylic acid, etc., but specific examples of the aromatic dicarboxylic acid are not limited thereto. In addition, the aliphatic dicarboxylic acid component may be an aliphatic dicarboxylic acid component having 4 to 20 carbon atoms, preferably 4 to 12 carbon atoms, or a mixture thereof. Examples of the aliphatic dicarboxylic acid include cyclohexanedicarboxylic acids such as 1,4-cyclohexanedicarboxylic acid and 1,3-cyclohexanedicarboxylic acid, phthalic acid, sebacic acid, succinic acid, isodecylsuccinic acid, Linear, branched, or cyclic aliphatic dicarboxylic acids such as maleic acid, fumaric acid, adipic acid, glutaric acid, and azelaic acid may be included, but specific examples of the aliphatic dicarboxylic acids are not limited thereto.

diol ingredient

Meanwhile, in the polyester copolymer of one embodiment, the diol component means a main monomer constituting the polyester copolymer together with the dicarboxylic acid component described above. In particular, the diol component includes isosorbide, cyclohexanedimethanol, and a diol having a fluorene ring, and may include ethylene glycol, or ethylene glycol and diethylene glycol.

The child carbide is used to improve the heat resistance of the polyester copolymer of one embodiment. Such sorbide can improve the glass transition temperature and heat resistance of the polyester copolymer due to its crystallinity. However, such isocarbide exhibits high water absorption characteristics under high temperature, thereby lowering the water stability of the copolymer of the embodiment, and due to its crystallinity, yellowness and haze of the copolymer may be increased or processability may be lowered. there is.

Considering this point, the copolymer of one embodiment contains 10 to 30 mol%, or 15 to 29 mol%, or It may be included in an amount of 20 to 27 mol%. If the residue content of the isocarbide is too low, the heat resistance of the copolymer of one embodiment may not be sufficient, and if the content is too high, the water stability and processability of the copolymer are lowered, or yellowness and haze increase. can do.

On the other hand, the cyclohexanedimethanol, for example, 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol or 1,4-cyclohexanedimethanol, the transparency of the polyester copolymer of one embodiment , can contribute to the improvement of mechanical properties such as impact strength.

In this respect, the copolymer of one embodiment contains 30 to 60 mole%, or 35 to 60 mole%, or 40 to 60 mole% of the cyclohexanedimethanol residue based on 100 mole% of the residues of the dicarboxylic acid component. It may be included in an amount of 60 mol%. If the cyclohexanedimethanol residue content is too low, the copolymer of one embodiment may not have sufficient impact strength or transparency, and if the content is too high, heat resistance of the copolymer may not be sufficiently secured.

Additionally, the copolymer of one embodiment further includes a residue of a diol having a fluorene ring to improve its water stability and reduce yellowness and haze. As the diol having a fluorene ring, fluorene-dialkanol, for example, 9H-fluorene-9,9-di(C1-C3)alkanol can be used, and representatively 9H-fluorene-9, 9-dimethanol may be used.

The copolymer of one embodiment contains 1 to 15 mol%, or 3 to 15 mol%, or 3 to 10 mol of the residue of the diol having a fluorene ring, based on 100 mol% of the residue of the dicarboxylic acid component. %, or may be included in an amount of 5 to 10 mol%. If the residue content of the diol having a fluorene ring is too low, the improvement of water stability or chromaticity of the copolymer of one embodiment may not be sufficient, and if the content is too high, mechanical properties such as impact strength of the copolymer are lowered It can be.

Meanwhile, the above-described copolymer of one embodiment may further include ethylene glycol residues, ethylene glycol residues, and diethylene glycol residues in addition to the diol components described above. At this time, the residue of the diethylene glycol may be derived from diethylene glycol by additionally using it in the process of preparing the polyester copolymer, but may also be derived from the ethylene glycol bonded in the form of a dimer. .

Residues of such ethylene glycol, or residues of ethylene glycol and diethylene glycol may be included in the residues of the diol component in a residual amount excluding the content of the residues of the aforementioned isosorbide, cyclohexanedimethanol, and diol having a fluorene ring. For example, these residues may be included in an amount of 5 to 30 mol%, 10 to 30 mol%, or 5 to 20 mol% based on 100 mol% of the residues of the dicarboxylic acid component. If the content of residues such as ethylene glycol is too low, basic polymerization reactivity may not be sufficient in the process of preparing the copolymer of one embodiment, and if the content is too high, other properties such as heat resistance of the copolymer may not be sufficient. .

polyester copolymer

As described above, the polyester copolymer of one embodiment may exhibit improved heat resistance, moisture stability, mechanical properties, low yellowness and haze, as it includes the residue of the diol component in a specific composition. The excellent properties of these copolymers can be defined by each of the following physical properties.

First, the copolymer of the embodiment has an intrinsic viscosity measured using a viscometer in a thermostat at 35 ° C after dissolving the copolymer at a concentration of 0.12% by weight in orthochlorophenol (OCP) at 150 ° C. 0.5 to 1.0 dL/g, or 0.6 to 0.9 dL/g. Due to such high intrinsic viscosity and degree of polymerization, the copolymer of one embodiment may exhibit excellent mechanical properties and heat resistance.

In addition, the copolymer of one embodiment has a glass transition temperature (Tg) of 100 ° C or higher, or 100 to 150 ° C, or 105 to 130 ° C, or 110 to 125 ° C, measured by DSC based on the ^2nd peak. It can show excellent heat resistance.

In addition, the copolymer of one embodiment includes a certain amount of the diol residue having a fluorene ring, and thus may exhibit excellent moisture stability and moisture absorption resistance. Such excellent resistance to moisture absorption can be evaluated by a low degree of change in the glass transition temperature of the copolymer after maintaining the copolymer at high temperature and high humidity.

For example, the copolymer of one embodiment has a glass transition temperature (Tg2) measured after being stored in a hot air oven at 85° C. for 3 days in a water-immersed state, and a glass transition temperature measured before storage in the hot air oven. Hygroscopic resistance (ΔTg), defined as the difference in temperature (Tg1) (Tg1-Tg2), is 6°C or less. or 0 to 6°C. Or it can be measured and calculated as 1 to 5 ° C.

This may define that the copolymer of one embodiment exhibits excellent moisture absorption resistance and moisture stability under high temperature even after exposure to high temperature and high humidity, with a small degree of change in glass transition temperature and heat resistance.

In addition, the polyester copolymer of one embodiment described above has, for example, in a pellet state immediately after polymerization, 0.1 to 2, or 0.2 to 1.8. Alternatively, a low Color b value of 0.3 to 1.5 may be indicated. As a result, the copolymer of one embodiment may exhibit low yellowness and excellent chromaticity characteristics.

Manufacturing method of polyester copolymer

Meanwhile, the polyester copolymer of one embodiment described above may be prepared by copolymerizing the dicarboxylic acid component and the diol component described above. In this case, the copolymerization may be sequentially performed by an esterification reaction and a polycondensation reaction.

The esterification reaction is performed in the presence of an esterification reaction catalyst, and an esterification reaction catalyst containing a zinc-based compound may be used. Specific examples of such zinc-based catalysts include zinc acetate, zinc acetate dihydrate, zinc chloride, zinc sulfate, zinc sulfide, zinc carbonate, zinc citrate, zinc gluconate, or mixtures thereof.

The esterification reaction may be carried out at a pressure of 0 to 10.0 kg/cm 2 and a temperature of 150 to 300° C. The esterification reaction conditions may be appropriately adjusted according to the specific characteristics of the polyester to be produced, the ratio of each component, or process conditions. Preferably, the esterification reaction is carried out at a pressure of 0 to 5.0 kg/cm 2 , more preferably at a pressure of 0.1 to 3.0 kg/cm 2 ; And it may be carried out at a temperature of 200 to 300 ℃, more preferably 240 to 280 ℃.

In addition, the esterification reaction may be carried out in a batch or continuous manner, and each raw material may be separately introduced, but it is preferable to introduce a slurry in which a diol component is mixed with a dicarboxylic acid component. . In addition, a diol component such as isocarbide, which is solid at room temperature, may be dissolved in water or ethylene glycol and then mixed with a dicarboxylic acid component such as terephthalic acid to form a slurry. Alternatively, after isosorbide is melted at 60 ° C. or higher, a slurry may be prepared by mixing a dicarboxylic acid component such as terephthalic acid and other diol components. In addition, water may be additionally added to the mixed slurry to help increase the fluidity of the slurry.

In addition, the polycondensation reaction, 150 to 300 ℃, preferably 200 to 290 ℃; and 600 to 0.01 mmHg, preferably 200 to 0.05 mmHg, more preferably 100 to 0.1 mmHg. By applying the reduced pressure condition of the polycondensation reaction, glycol, which is a by-product of the polycondensation reaction, can be removed out of the system. Accordingly, when the polycondensation reaction is out of the reduced pressure condition range of 400 to 0.01 mmHg, removal of the by-product may be insufficient. there is. In addition, when the polycondensation reaction occurs outside the temperature range of 150 to 300 ° C., when the polycondensation reaction proceeds below 150 ° C., glycol, a by-product of the polycondensation reaction, cannot be effectively removed out of the system, resulting in low intrinsic viscosity of the final reaction product. The physical properties of the polyester resin may be deteriorated, and when the reaction proceeds at 300 ° C. or higher, the appearance of the polyester resin produced is likely to become yellow. In addition, the polycondensation reaction may proceed for a necessary time until the intrinsic viscosity of the final reaction product reaches an appropriate level, for example, an average residence time of 1 to 24 hours.

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

Examples of the titanium compound include tetraethyl titanate, acetyl tripropyl titanate, tetrapropyl titanate, tetrabutyl titanate, 2-ethylhexyl titanate, octylene glycol titanate, lactate titanate, and triethanolamine titanate. nate, acetylacetonate titanate, ethyl acetoacetic ester titanate, isostearyl titanate, titanium dioxide and the like. Examples of the germanium-based compound include germanium dioxide, germanium tetrachloride, germanium ethylene glycol oxide, germanium acetate, copolymers using these, or mixtures thereof. Preferably, germanium dioxide can be used, and both crystalline and amorphous germanium dioxide can be used, and glycol-soluble ones can also be used.

The polyester copolymer of one embodiment prepared by the above-described method exhibits excellent heat resistance, moisture stability, mechanical properties, and low yellowness and haze characteristics at the same time, so it can be used very preferably for the manufacture of various molded articles requiring heat resistance. can

Such molded articles may be various food/beverage containers, packaging materials, medical devices, or heat-resistant sheets for which heat resistance and moisture stability are particularly required.

Meanwhile, since the molded article may be manufactured according to a general molding and processing method of polyester, except that it is manufactured using the polyester copolymer of one embodiment, further description thereof will be omitted.

The above-described polyester copolymer according to the present invention exhibits improved heat resistance and stability, and exhibits low haze and yellowness characteristics and excellent mechanical properties, compared to conventional heat-resistant polyester copolymers.

Accordingly, these polyester copolymers can be very preferably used in the manufacture of various molded articles that are exposed to high temperature and high humidity and require heat resistance and moisture stability.

Hereinafter, a preferred embodiment is presented to aid understanding of the present invention. However, the following examples are only provided to more easily understand the present invention, and the content of the present invention is not limited thereby.

Examples 1 to 6

The polyester copolymers of Examples were prepared by the following method.

First, 100 mol% of dicarboxylic acid (terephthalic acid (TPA)) and diol (9H-fluorene-9,9-dimethanol ( FLDM), 1,4-cyclodimethanol (CHDM), and ethylene glycol (EG)) raw materials were added. At this time, the input content range of each diol based on 100 mol% of the dicarboxylic acid is as summarized in Table 1 below, and the input content of these dicarboxylic acids and diols is finally prepared in each example. The content ranges of dicarboxylic acid and diol residues in the polyester copolymer were the same.

Here, triethyl phosphate (TEP) as a phosphorus stabilizer and germanium dioxide (GeO2) as a catalyst were added in the contents of Table 1 based on the content of the central atom, respectively, and then the pressure was reduced to 2.0 kg with nitrogen. / cm 2 and reacted while raising the temperature of the reactor to 220 to 250 ° C.

The water generated at this time is flowed out of the system for esterification, and when the generation and outflow of water is completed, the reactants are transferred to a polycondensation reactor equipped with an agitator, a cooling condenser, and a vacuum system, at a pressure of 1 mmHg or less and a temperature of 250 to 280˚C. The polycondensation reaction proceeded, and when the intrinsic viscosity of the reactants reached the maximum value, the polymerization was terminated.

The polyester copolymers of Examples 1 to 6 were prepared through the above-described process, and their physical properties are shown in Table 1 below.

Content based on 100 mol% of TPA Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 diol ingredient FLDM (mole %) 3 5 5 10 10 15 ISB (mol%) 27 25 25 20 20 20 CHDM (mole %) 40 50 60 40 50 60 EG (mole %) 30 20 10 30 20 5 additive GeO2 (ppm) 250 250 250 250 250 250 TEP (ppm) 100 100 100 100 100 100 basic properties
(Chip) Intrinsic Viscosity (dL/g) 0.66 0.65 0.67 0.65 0.65 0.63 Pellet col b 1.5 0.8 1.2 0.5 0.3 0.6 2nd Tg (℃) 110 112 113 112 114 120 mechanical properties Izod impact strength (3.2T) 830 700 860 450 500 520 Water Immersion Test Whether haze occurs X X X X X X Hygroscopicity Tg(Δ) (℃) 4.7 4.0 4.3 3.8 3.5 3.3

Comparative Examples 1 to 4

Except for using 9H-fluorene-9,9-dimethanol (FLDM) or isocarbide (ISB) as a diol component and adding raw materials such as each diol, phosphorus stabilizer and catalyst according to the composition of Table 2 below Then, the polyester copolymers of Comparative Examples 1 to 4 were prepared in the same manner as in Examples 1 to 6, and their physical properties are shown in Table 2 below.

Content based on 100 mol% of TPA Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 diol ingredient FLDM (mole %) 0 0.5 17 20 ISB (mol %) 25 29.5 18 15 CHDM (mole %) 50 50 40 50 EG (mole %) 25 20 25 15 additive GeO2 (ppm) 250 250 250 250 TEP (ppm) 100 100 100 100 basic properties
(Chip) Intrinsic Viscosity (dL/g) 0.67 0.65 0.62 0.63 Pellet col b 2.5 2.8 1.2 0.5 2nd Tg (℃) 110 119 118 121 mechanical properties Izod impact strength (3.2T) 860 820 120 95 Water Immersion Test Whether haze occurs O O X X Hygroscopicity Tg(Δ) (℃) 12.0 10.5 2.5 2.0

Experimental Example

With respect to the copolymers prepared in the above Examples and Comparative Examples, physical properties were evaluated as follows, and the results are summarized in Tables 1 and 2 above.

1) Intrinsic viscosity: After dissolving a polyester copolymer at a concentration of 0.12% by weight in orthochlorophenol (OCP) at 150 ° C, it was measured using a Ubel rod-type viscometer in a constant temperature bath at 35 ° C.

2) Color b: For the polyester copolymer in a pellet state, Color b was measured by measuring the color of the specimen using Pacific Scientific's Colorgard System.

3) Glass transition temperature (Tg): The polyester resin was annealed at 300 ° C. for 5 minutes, cooled to room temperature, and the Tg was measured again at a heating rate of 10 ° C./min during 2nd Scan. .

4) IZOD impact strength: In accordance with ASTM D256, a specimen for measurement (the thickness of the specimen is 1/8” (3.2T)) is made and Izod notched at a temperature of 25℃ using an Izod impactor (Impact Tester, Yasuda equipment) The impact strength of the type was measured.

5) Haze (%): In accordance with JIS (Japanese Industrial Standards) K7136, the haze (%) of three different locations of the measured specimen was measured with a haze meter (device name: NDH2000, manufacturer: Nippon Denshoku (Japan)). By measuring, the average value of each measurement result was calculated as the result value.

In this haze measurement, a specimen for measurement (the thickness of the specimen was 1/4” (6.4T) was made and used, and after putting this specimen in a sealed container filled with water, it was stored for a long period of time (more than 9 days), and the number of days (1/3/6/9 days), specimens were taken out and the above haze was measured. Based on these measurement results, the following criteria were evaluated.

X: Less than 10% of the measured value when measuring Haze (%) after 9 days

O: 10% or more of the measured value when measuring Haze (%) after 9 days

6) Hygroscopicity (ΔTg, Tg1 (2nd Tg)-Tg2 (1st Tg))

The polyester copolymer sample in the chip state was put into a 20ml vial, filled with water, and stored in an 85° C. hot air oven for 3 days. Thereafter, by removing moisture from the surface as much as possible, Tg2 (1st Tg) was measured by DSC. Tg1 (2nd Tg) before storage in the hot air oven was measured, and moisture absorption resistance (ΔTg) was calculated as the difference between them (Tg1-Tg2).

ΔTg = Tg1 (2nd Tg) - Tg2 (1st Tg)

Tg1 (2nd Tg): 2nd Tg value measured without pretreatment after polymerization

Tg2 (1st Tg): 1st Tg value measured after pretreatment under conditions of high temperature and high humidity (after immersion in water, storage in a hot air oven at 85℃)

For reference, the Tg1 and Tg2 were measured under the same DSC equipment and elevated temperature conditions as the 3) glass transition temperature (Tg). However, in the case of 3) glass transition temperature (Tg) measurement, considering that the Tg value in the first scan may affect the thermal analysis result of the resin after polymerization, the thermal history remaining in the resin may affect the second The Tg value in the scan was taken, but in this hygroscopicity evaluation, Tg2 was calculated by confirming the Tg value in the first scan because it may be affected by thermal decomposition depending on the number of scans after pretreatment under high temperature and high humidity.

Referring to Tables 1 and 2, it was confirmed that the polyester copolymers of Examples exhibit high intrinsic viscosity, excellent heat resistance (high Tg), moisture absorption resistance and impact strength, and exhibit low color b values and haze.

On the other hand, it was confirmed that the polyester copolymer of Comparative Example had poor moisture absorption resistance or impact strength, or exhibited a high color b value and haze compared to Examples.

Claims (11)

residues of dicarboxylic acid components including terephthalic acid; and
Residues of diol components including isocarbide, cyclohexanedimethanol and diols having a fluorene ring;
Based on 100 mol% of the residues of the dicarboxylic acid component, the residues of the diol having a fluorene ring are included in an amount of 1 to 15 mol%.
The method of claim 1, wherein the residue of the dicarboxylic acid component is dimethyl terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, diphenyl dicarboxylic acid, 4,4'-stilbendicarboxylic acid , 2,5-furandicarboxylic acid, 2,5-thiophenedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid phthalic acid, sebacic acid, succinic acid, iso A polyester copolymer further comprising at least one residue selected from the group consisting of decylsuccinic acid, maleic acid, fumaric acid, adipic acid, glutaric acid and azelaic acid.
The polyester copolymer according to claim 1, wherein the diol having a fluorene ring includes 9H-fluorene-9,9-dialkanol.
The polyester copolymer according to claim 4, wherein the residue of the diol component further comprises a residue of ethylene glycol, or a residue of ethylene glycol and a residue of diethylene glycol.
The method of claim 4, based on 100 mol% of the residues of the dicarboxylic acid component,
The residue of the diol component is 10 to 30 mol% of the residue of the isocarbide, 30 to 60 mol% of the residue of the cyclohexanedimethanol, 1 to 15 mol% of the residue of the diol having a fluorene ring, and the A polyester copolymer comprising 5 to 30 mole % of ethylene glycol or residues of ethylene glycol and diethylene glycol.
According to claim 1, after dissolving the polyester copolymer at a concentration of 0.12% by weight in orthochlorophenol (OCP) at 150 ° C, the intrinsic viscosity measured using a viscometer in a constant temperature bath at 35 ° C is 0.5 to 1.0 dL/g polyester copolymer, The polyester copolymer according to claim 1, having a glass transition temperature (Tg) of 100 to 150 °C.
The method of claim 7, wherein the glass transition temperature (Tg2) measured after storing the polyester copolymer in a water-immersed state in a hot air oven at 85 ° C. for 3 days, and the glass transition temperature measured before storage in the hot air oven A polyester copolymer having moisture absorption resistance (ΔTg) defined as a difference in temperature (Tg1) (Tg1-Tg2) of 6°C or less.
The polyester copolymer according to claim 1, wherein the polyester copolymer in a pellet state immediately after polymerization has a Color b value of 0.1 to 2.
A molded article comprising the polyester copolymer of any one of claims 1 to 9.
The molded article according to claim 10, selected from the group consisting of food containers, packaging materials, medical devices and heat-resistant sheets.