Polyester resin and method for producing the same

Abstract

To provide a polyester resin that exhibits a high refractive index.SOLUTION: A polyester resin has a structural unit derived from a compound represented by the following formula (1) and a structural unit derived from a dicarboxylic acid compound [wherein two of R1 to R4 are hydrogen, and the other two of R1 to R4 are each independently a hydroxy C1-4 alkyl ether group].SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a polyester resin having structural units derived from a dibenzo[g,p]chrysene diol compound and a method for producing the same. [Background technology]

[0002] BACKGROUND ART For example, compounds having a dibenzo[g,p]chrysene skeleton and compounds having a fluorene skeleton are known as raw materials for optical resins used in the production of optical products such as optical films and optical lenses.

[0003] Substituted dibenzo[g,p]chrysene has attracted attention as a material with organic electroluminescence and semiconductor resist properties. Among polycyclic aromatic hydrocarbon compounds, dibenzo[g,p]chrysene is characterized by a helically twisted π-conjugated structure. By adjusting the structure of the dibenzo[g,p]chrysene skeleton, it is possible to manipulate optical and electronic properties such as good hole mobility, high quantum yield, and long excited-state lifetime. A method for producing substituted dibenzo[g,p]chrysene is disclosed, for example, in Patent Document 1.

[0004] Furthermore, compounds having a fluorene skeleton are known to have excellent functions such as a high refractive index and high heat resistance. A method for producing a compound having a fluorene skeleton is disclosed in, for example, Patent Document 2. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-227307 [Patent Document 2] Japanese Patent Application Laid-Open No. 2011-68624 Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present invention is to provide a polyester resin having a high refractive index. [Means for solving the problem]

[0007] The present inventors have found that a polyester resin having a structural unit derived from a dibenzo[g,p]chrysene compound having a specific structure has a high refractive index.

[0008] The present invention includes the following embodiments. [1] A structural unit derived from a compound represented by the following formula (1), [ka] [In the formula, R 1 ~R 4 Two of them are hydrogen, R 1 ~R 4 The other two of the groups are each independently hydroxy C 1-4 alkyl ether group] a structural unit derived from a dicarboxylic acid compound; A polyester resin having the formula: [2] The formula (1) is the following formula (1-1): [ka] [In the formula, R 1 ~R 4 The polyester resin according to [1], wherein the polyester resin is as described above. [3] The dicarboxylic acid compound is At least one aromatic dicarboxylic acid compound selected from the group consisting of dicarboxylic acids represented by the following formula (2) and esters thereof; [ka] wherein Z is a monocyclic or polycyclic aromatic ring. At least one fluorene-based dicarboxylic acid compound selected from the group consisting of dicarboxylic acids represented by the following formula (3) and esters thereof; [ka] [where, X 1 are each independently 1-8 an alkylene group] The polyester resin according to [1] or [2], [4] [3] The polyester resin according to [3], wherein Z in the formula (2) is a benzene ring, a naphthalene ring, or a binaphthalene ring. [5] a structural unit derived from the aromatic dicarboxylic acid compound; a structural unit derived from the fluorene-based dicarboxylic acid compound; The polyester resin according to [3] or [4], wherein the molar ratio of [6] A structural unit derived from an aliphatic diol compound represented by the following formula (4): [ka] [where, X 2 is C 2-8 an alkylene group] The polyester resin according to any one of [1] to [5], further comprising: [7] A structural unit derived from a compound represented by formula (1), a structural unit derived from the aliphatic diol compound; The polyester resin according to [6], wherein the molar ratio of [8] An optical film comprising the polyester resin according to any one of [1] to [7]. [9] An optical lens comprising the polyester resin according to any one of [1] to [7].

[10] A compound represented by the following formula (1), [ka] [In the formula, R 1 ~R 4 Two of them are hydrogen, R 1 ~R 4 The other two of the groups are each independently hydroxy C 1-4 alkyl ether group] a dicarboxylic acid compound; A method for producing a polyester resin, comprising a polymerization step of reacting

[11] The dicarboxylic acid compound is At least one aromatic dicarboxylic acid compound selected from the group consisting of dicarboxylic acids represented by the following formula (2) and esters thereof; [ka] wherein Z is a monocyclic or polycyclic aromatic ring. At least one fluorene-based dicarboxylic acid compound selected from the group consisting of dicarboxylic acids represented by the following formula (3) and esters thereof; [ka] [where, X 1 are each independently 1-8 an alkylene group] The method for producing a semiconductor device according to

[10] , comprising: [Effects of the Invention]

[0009] The present invention can provide a polyester resin having a high refractive index. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 shows the 1H-NMR spectrum of Compound A synthesized in Synthesis Example 1. [Figure 2] FIG. 2 shows the 13C-NMR spectrum of Compound A synthesized in Synthesis Example 1. [Figure 3] FIG. 3 shows the 1H-NMR spectrum of Compound B synthesized in Synthesis Example 2. [Figure 4] FIG. 4 shows the 13C-NMR spectrum of Compound B synthesized in Synthesis Example 2. [Figure 5] FIG. 5 shows the 1H-NMR spectrum of Compound C synthesized in Synthesis Example 3. [Figure 6] FIG. 6 shows the 13C-NMR spectrum of Compound C synthesized in Synthesis Example 3. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments of the present invention will be described in detail, but the present invention is not limited to these and various modifications are possible without departing from the gist of the present invention.

[0012] <Polyester resin> One embodiment of the present invention relates to a polyester resin having structural units derived from a dibenzo[g,p]chrysene diol compound and structural units derived from a dicarboxylic acid compound.

[0013] The polyester resin according to this embodiment has excellent moldability and a high refractive index, and is therefore suitable for producing optical products.

[0014] [Dibenzo[g,p]chrysene-based diol compounds] The polyester resin according to this embodiment has a structural unit derived from a dibenzo[g,p]chrysene-based diol compound. The dibenzo[g,p]chrysene-based diol compound is a compound represented by the following formula (1): [ka] [In the formula, R 1 ~R 4 Two of them are hydrogen, R 1 ~R 4 The other two of the groups are each independently hydroxy C 1-4alkyl ether group]

[0015] The compound represented by formula (1) has a high refractive index and high heat resistance, and therefore can be suitably used as an optical material.

[0016] In the formula (1), R 1 and R 2 is hydrogen and R 3 and R 4 is hydroxy C 1-4 An alkyl ether group is preferred.

[0017] In the formula (1), R 1 and R 3 is hydrogen and R 2 and R 4 is hydroxy C 1-4 An alkyl ether group is preferred.

[0018] In the formula (1), R 1 and R 4 is hydrogen and R 2 and R 3 is hydroxy C 1-4 An alkyl ether group is preferred.

[0019] In the formula (1), the hydroxy C 1-4 The alkyl ether group is a hydroxy C 2-3 An alkyl ether group is preferred, and a hydroxy C2 alkyl ether group is more preferred.

[0020] The above (1) is preferably the following formula (1-1) from the viewpoint of having a higher refractive index and higher heat resistance. [ka] [In the formula, R 1 ~R 4 is as stated above]

[0021] [Method of producing dibenzo[g,p]chrysene diol compounds] The compound represented by the formula (1) can be produced, for example, by a method including a reaction step of hydroxyalkylating a compound represented by the following formula (P1): [ka] [In the formula, R 5 ~R 8 Two of them are hydrogen, R 5 ~R 8 the other two are hydroxy groups]

[0022] Examples of the hydroxyalkylation method include a method in which the compound of formula (P1) is reacted with an alkylene carbonate, a halogenated alkanol, or an alkylene oxide.

[0023] The compound represented by the formula (1) (wherein R 1 ~R 4 In the case of producing the compound (I), two of which are hydroxy C1 alkyl ether groups, it is preferred to use 1-chloromethanol as the halogenated alkanol in the hydroxyalkylation.

[0024] The compound represented by the formula (1) (wherein R 1 ~R 4 In the case of producing the compound (C2 alkyl ether), it is preferred to use ethylene carbonate as the alkylene carbonate, 1-chloroethanol as the halogenated alkanol, or ethylene oxide as the alkylene oxide in the hydroxyalkylation.

[0025] The compound represented by the formula (1) (wherein R 1 ~R 4In the case of producing the compound (I), two of which are hydroxy C3 alkyl ether groups, it is preferred to use 1-chloropropanol as the halogenated alkanol or epichlorohydrin as the alkylene oxide in the hydroxyalkylation.

[0026] The compound represented by the formula (1) (wherein R 1 ~R 4 In the case of producing the compound (C4 alkyl ether), it is preferred to use 1-bromobutanol as the halogenated alkanol in the hydroxyalkylation.

[0027] The molar ratio of the compound represented by the formula (P1) to the alkylene carbonate, halogenated alkanol, or alkylene oxide is preferably 1.0:2.0-4.0, more preferably 1.0:2.0-3.0, and even more preferably 1.0:2.0-2.5.

[0028] The reaction step is preferably carried out in the presence of a base, such as potassium carbonate, sodium carbonate, lithium carbonate, triethylamine, diazabicycloundecene, and ethyldiisopropylamine.

[0029] The reaction step is preferably carried out in the presence of a solvent. Examples of the solvent include aromatic hydrocarbon solvents, halogenated solvents, amine solvents, amide solvents, alcohol solvents, nitrile solvents, ketone solvents, and ether solvents. The solvent may be used alone or in combination of two or more.

[0030] Examples of aromatic hydrocarbon solvents include benzene, toluene, and xylene.

[0031] Halogen-based solvents include, for example, methylene chloride, chloroform, and carbon tetrachloride.

[0032] Examples of amine solvents include pyridine, 4-methylpyridine, and 2,6-dimethylpyridine.

[0033] Examples of amide solvents include dimethylformamide, dimethylacetamide, N-methyl-2-pyrrolidone, and N,N'-dimethylpropyleneurea.

[0034] Examples of alcohol-based solvents include methanol, ethanol, isopropanol, butanol, and hexanol.

[0035] Examples of nitrile solvents include acetonitrile and propionitrile.

[0036] Examples of ketone solvents include acetone, cyclohexanone, cyclopentanone, methyl ethyl ketone, and methyl isopropyl ketone.

[0037] Examples of ether solvents include diethyl ether, tetrahydrofuran, methyl tert-Bu-ether, cyclopentyl methyl ether, and dioxane.

[0038] The reaction temperature in the reaction step is not particularly limited, but may be, for example, 20 to 200°C, 50 to 190°C, or 100 to 180°C.

[0039] From the viewpoint of synthesizing a compound having a higher refractive index and higher heat resistance, the (P1) is preferably the following formula (P1-1). [ka] [In the formula, R 5 ~R 8 is as stated above].

[0040] [Dicarboxylic acid compounds] The polyester resin according to this embodiment has structural units derived from a dicarboxylic acid compound (including dicarboxylic acids and their esters).

[0041] Examples of the dicarboxylic acid compound include: at least one aromatic dicarboxylic acid compound selected from the group consisting of dicarboxylic acids represented by the following formula (2) and esters thereof; [ka] wherein Z is a monocyclic or polycyclic aromatic ring; and At least one fluorene-based dicarboxylic acid compound selected from the group consisting of dicarboxylic acids represented by the following formula (3) and esters thereof: [ka] [where, X 1 are each independently 1-8 an alkylene group] Examples include:

[0042] The polyester resin according to the present embodiment may have only one of the structural units derived from the aromatic dicarboxylic acid compound and the structural units derived from the fluorene-based dicarboxylic acid compound, but preferably has both.

[0043] By including the structural units derived from the aromatic dicarboxylic acid compound, the refractive index of the polyester resin tends to increase. By including the structural unit derived from the fluorene-based dicarboxylic acid compound, the refractive index and heat resistance of the polyester resin tend to be increased.

[0044] Examples of Z in the formula (2) include a benzene ring, a naphthalene ring, and a binaphthalene ring.

[0045] Examples of the ester of the dicarboxylic acid represented by the formula (2) include C 1-6 Alkyl esters, C1-3 Only one of the carboxylic acids may be esterified, or both may be esterified.

[0046] In the formula (3), X 1 are each independently 1-8 It is an alkylene group. 1 are each independently 1-6 Alkylene group, C 1-4 Alkylene group, C 1-2 It may be an alkylene group or a C2 alkylene group.

[0047] Examples of the ester of the dicarboxylic acid represented by the formula (3) include C 1-6 Alkyl esters, C 1-3 Only one of the carboxylic acids may be esterified, or both may be esterified.

[0048] The molar ratio of the structural units derived from the aromatic dicarboxylic acid compound to the structural units derived from the fluorene-based dicarboxylic acid compound is preferably 20:80 to 80:20.The molar ratio can be determined by analysis using a nuclear magnetic resonance spectrometer.

[0049] [Aliphatic diol compounds] The polyester resin according to this embodiment may further include a structural unit derived from an aliphatic diol compound represented by the following formula (4). [ka] [where, X 2 is C 2-8 an alkylene group]

[0050] By including a structural unit derived from the aliphatic diol compound, the flexibility of the polyester resin tends to be increased.

[0051] In the formula (4), X 2 is C 2-8 It is an alkylene group. 2 is C 2-6 Alkylene group, C 2-4 Alkylene group, C 2-3 It may be an alkylene group or a C2 alkylene group.

[0052] The molar ratio of the structural units derived from the compound represented by formula (1) to the structural units derived from the aliphatic diol compound represented by formula (4) is preferably 99:1 to 50:50. The molar ratio can be determined by analysis using a nuclear magnetic resonance spectrometer.

[0053] [Polyester resin] The total of the structural units derived from the compound represented by formula (1), the structural units derived from the aromatic dicarboxylic acid compound, the structural units derived from the fluorene-based dicarboxylic acid compound, and the structural units derived from the aliphatic diol compound is preferably 70 to 100 mol %, more preferably 80 to 100 mol %, even more preferably 90 to 100 mol %, and particularly preferably 95 to 100 mol %, based on all the structural units constituting the polyester resin.

[0054] The polyester resin according to the present embodiment may contain additional structural units to the extent that they do not adversely affect the intended use. The additional structural units are not particularly limited, and any structural units known as structural units for polyester resins may be used.

[0055] The refractive index of the polyester resin according to this embodiment is preferably 1.68 to 1.78, more preferably 1.69 to 1.75, and even more preferably 1.70 to 1.72. Polyester resins exhibiting such refractive indices are particularly suitable for the production of optical products. The refractive index can be adjusted by changing the composition of the structural units constituting the polyester resin. For example, the refractive index of the polyester resin can be increased by increasing the proportion of a monomer compound exhibiting a high refractive index. The refractive index can be measured by the method described in the examples below.

[0056] The Abbe number of the polyester resin according to this embodiment is preferably 10 to 21, more preferably 12 to 19, and even more preferably 14 to 17. Since the Abbe number is usually inversely correlated with the refractive index, the Abbe number can be reduced by increasing the refractive index. The Abbe number can be measured by the method described in the examples below.

[0057] The glass transition temperature (Tg) of the polyester resin according to this embodiment is preferably 120 to 180°C, more preferably 130 to 170°C, and even more preferably 140 to 160°C. Polyester resins exhibiting such a Tg are particularly excellent in moldability. Tg can be adjusted by changing the composition of the structural units that make up the polyester resin. Tg can be measured by the method described in the examples below.

[0058] <Method of manufacturing polyester resin> One embodiment of the present invention relates to a method for producing a polyester resin, which includes a polymerization step of reacting a compound represented by the formula (1) with a dicarboxylic acid compound.

[0059] Examples of the dicarboxylic acid compound used in the production method according to this embodiment include at least one aromatic dicarboxylic acid compound selected from the group consisting of the dicarboxylic acid represented by the above formula (2) and its esters, and at least one fluorene-based dicarboxylic acid compound selected from the group consisting of the dicarboxylic acid represented by the above formula (3) and its esters. It is possible to use only one of the aromatic dicarboxylic acid compound and the fluorene-based dicarboxylic acid compound, but it is preferable to use both. Details of the aromatic dicarboxylic acid compound and the fluorene-based dicarboxylic acid compound are as described in the column of [Dicarboxylic Acid Compound].

[0060] In the production method according to this embodiment, the aliphatic diol compound represented by the above formula (4) may be further polymerized. Details of the aliphatic diol compound are as described in the column of [Aliphatic Diol Compound].

[0061] The polymerization reaction is preferably carried out in the presence of a transesterification catalyst. The transesterification catalyst is not particularly limited, and a catalyst generally used in the synthesis of polyester resins may be employed.

[0062] The temperature of the polymerization reaction is not particularly limited, but for example, it may be 200 to 350 °C, 240 to 300 °C, or 270 to 280 °C.

[0063] <Optical Product> One embodiment of the present invention relates to an optical product containing the polyester resin. Examples of the optical product include an optical film and an optical lens.

Examples

[0064] Hereinafter, the present invention will be described in more detail using examples and comparative examples, but the technical scope of the present invention is not limited thereto.

[0065] <Synthesis of Compounds> [Synthesis Example 1] (Synthesis of 3,14-bis(2-hydroxyethoxy)dibenzo[g,p]chrysene (Compound A)) Under an argon atmosphere, potassium carbonate (1.41 g, 10.2 mmol) and ethylene carbonate (1.12 g, 12.7 mmol) were added to a solution of 3,14-dihydroxydibenzo[g,p]chrysene (1.83 g, 5.08 mmol) in anhydrous N,N-dimethylformamide (50 mL). The reaction solution was reacted at 175°C, and then the reaction was stopped using 1 M aqueous hydrochloric acid at 0°C. The organic layer was separated, and the aqueous layer was extracted with ethyl acetate. The combined organic layer was washed with saturated brine, dried over sodium sulfate, concentrated to remove the solvent, and dried in vacuo to obtain 3.51 g of a crude product as a yellowish-white solid. Column purification using silica gel yielded 1.94 g (85%) of the target product as a whitish-yellow solid. Compound A 1 The H-NMR spectrum of compound A is shown in Figure 1. 13 The C-NMR spectrum is shown in Figure 2. [ka]

[0066] [Synthesis Example 2] (Synthesis of 3,11-bis(2-hydroxyethoxy)dibenzo[g,p]chrysene (Compound B)) Under an argon atmosphere, potassium carbonate (3.1 g, 22 mmol) and ethylene carbonate (2.5 g, 28 mmol) were added to a solution of 3,11-dihydroxydibenzo[g,p]chrysene (4.1 g, 11 mmol) in anhydrous N,N-dimethylformamide (100 mL). The reaction solution was reacted at 175°C, and then the reaction was stopped using a 3M aqueous hydrochloric acid solution at 0°C. The organic layer was separated, and the aqueous layer was extracted with ethyl acetate. The combined organic layer was washed with saturated brine, dried over sodium sulfate, concentrated to remove the solvent, and dried in vacuo to obtain 6.6 g of a crude product as a brown solid. 3.6 g (72%) of the target product was obtained as a white solid by filtration column purification using silica gel, and then white crystals (54%) were obtained by recrystallization. Compound B 1 The H-NMR spectrum of compound B is shown in Figure 3. 13 The C-NMR spectrum is shown in Figure 4. [ka]

[0067] [Synthesis Example 3] (Synthesis of 3,6-bis(2-hydroxyethoxy)dibenzo[g,p]chrysene (Compound C)) Under an argon atmosphere, potassium carbonate (2.1 g, 15 mmol) and ethylene carbonate (1.7 g, 19 mmol) were added to a solution of 3,6-dihydroxydibenzo[g,p]chrysene (2.7 g, 7.6 mmol) in anhydrous N,N-dimethylformamide (74 mL). After reacting the reaction solution at 175°C, the reaction was stopped using 3M aqueous hydrochloric acid at 0°C, the organic layer was separated, and the aqueous layer was extracted with ethyl acetate. The combined organic layer was washed with saturated brine, dried over sodium sulfate, concentrated to remove the solvent, and dried under vacuum to obtain 3.6 g of a crude product as a yellow-white solid. Purification was performed using a silica gel filtration column to obtain 2.8 g (83%) of the target product as a white solid, which was then recrystallized to obtain white crystals (55%). Compound C 1 The H-NMR spectrum of compound C is shown in Figure 5. 13 The C-NMR spectrum is shown in Figure 6. [ka]

[0068] [Comparative Synthesis Example 1] 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene (BPEF) (manufactured by Osaka Gas Chemicals Co., Ltd.) was used as Comparative Synthesis Example 1.

[0069] <Compound evaluation> The compounds of the above Synthesis Examples and Comparative Synthesis Examples were evaluated as follows.

[0070] [Refractive index nD] Measurement was performed using a refractometer (DR-M2 (circulating constant temperature water bath 60-C3) manufactured by Atago Co., Ltd.) at a temperature of 25°C and a wavelength of 589 nm (D line). Specifically, compound A was dissolved in DMSO to prepare solutions with concentrations of 10.0 mass%, 20.0 mass%, and 25.0 mass%, compound B was dissolved in NMP to prepare solutions with concentrations of 10.0 mass%, 20.0 mass%, and 30.0 mass%, and compound C was dissolved in NMP to prepare solutions with concentrations of 10.0 mass%, 20.0 mass%, and 25.0 mass%, and the refractive index of the obtained solutions was measured to prepare a calibration curve (approximate straight line), and the concentration was determined by extrapolating to 100 mass%.

[0071] [Heat resistance evaluation] Using a thermogravimetry-differential thermal analyzer (TG-DTA) (TG / DTA6200 manufactured by SII NanoTechnology Inc.), the temperature at which the sample lost 5% by mass was measured under conditions of a nitrogen atmosphere and a heating rate of 10°C / min.

[0072] [Evaluation results] [Table 1]

[0073] <Synthesis of polyester resin> [Example 1] The reactor was charged with Compound A (4.0 × 10 -3 mol), ethylene glycol (hereinafter referred to as "EG") (10.2 x 10 -3 mol), dimethyl 2,6-naphthalenedicarboxylate (hereinafter referred to as "DMN") (1.4 × 10 -3 mol), 9,9-di(2-methoxycarbonylethyl)fluorene (hereinafter referred to as "FDPM") (3.3 × 10 -3 mol), and manganese acetate tetrahydrate (9.6 × 10 -7 The mixture was gradually heated to melt while stirring under a nitrogen atmosphere, and after the temperature was raised to 250°C, the mixture was stirred for 3 hours to carry out an ester exchange reaction. -6mol) and germanium dioxide aqueous solution (14.5 × 10 -6 The mixture was stirred, and the temperature was gradually increased and the pressure reduced to 275°C and 0.4 kPa or less, while the ethylene glycol was removed. After the specified pressure reduction and temperature were reached, the mixture was stirred for 4 hours, and the contents were removed from the reactor to obtain polyester resin pellets. The molar ratio of compound A to EG was 85:15. FDPM was synthesized by using methyl acrylate instead of t-butyl acrylate in Example 1 of JP-A-2005-89422.

[0074] [Example 2] Polyester resin pellets were obtained in the same manner as in Example 1, except that compound A in Example 1 was changed to compound B obtained in Synthesis Example 2. The molar ratio of compound B to EG was 85:15.

[0075] [Example 3] Polyester resin pellets were obtained in the same manner as in Example 1, except that compound A in Example 1 was changed to compound C obtained in Synthesis Example 3. The molar ratio of compound C to EG was 85:15.

[0076] [Comparative Example 1] Polyester resin pellets were obtained in the same manner as in Example 1, except that compound A in Example 1 was changed to a compound represented by the following formula (X) (hereinafter referred to as "compound X"). The molar ratio of compound X to EG was 85:15. Compound X was synthesized according to the method described in Example 1 of JP-A No. 2023-10230. [ka]

[0077] Comparative Example 2 Polyester resin pellets were obtained in the same manner as in Example 1, except that compound A in Example 1 was changed to 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene (BPEF) (manufactured by Osaka Gas Chemicals Co., Ltd.). The molar ratio of BPEF to EG was 85:15.

[0078] [Example 4] The reactor was charged with Compound A (12.0 × 10 -3 mol), EG (34.4 × 10 -3 mol), FDPM (16.0 × 10 -3 mol), and manganese acetate tetrahydrate (3.2 × 10 -6 The mixture was gradually heated to melt while stirring under a nitrogen atmosphere, and after the temperature was raised to 250°C, the mixture was stirred for 3 hours to carry out an ester exchange reaction. -6 mol) and germanium dioxide aqueous solution (48.2 × 10 -6 The mixture was stirred, and the temperature was gradually increased and the pressure reduced to 275°C and 0.4 kPa or less, while the ethylene glycol was removed. After the specified pressure reduction and temperature were reached, the mixture was stirred for 4 hours, and the contents were removed from the reactor to obtain polyester resin pellets. The molar ratio of compound A to EG was 75:25.

[0079] Comparative Example 3 Polyester resin pellets were obtained in the same manner as in Example 4, except that compound A in Example 4 was changed to 9,9-bis[6-(2-hydroxyethoxy)-2-naphthyl]fluorene (BNEF).

[0080] <Evaluation of polyester resin> The polyester resins of the above examples and comparative examples were evaluated as follows.

[0081] [Polymer composition] The sample was dissolved in deuterated chloroform containing tetramethylsilane as an internal standard, and the NMR spectrum was measured using a nuclear magnetic resonance spectrometer (BRUKER "AVANCE III HD"). 1 The H-NMR spectrum was measured. For the obtained spectrum, the integral values ​​of the peaks derived from each monomer used in the polymerization were determined, and the proportion of each monomer component (structural unit) introduced into the polymer was calculated.

[0082] [Refractive index nD] The refractive indexes of the resin samples of Examples 1 to 3 and Comparative Examples 1 and 2 were measured as follows. The resin samples were heat-pressed at 200 to 240°C to form films with thicknesses of 200 to 300 μm. These films were cut into strips measuring 20 to 30 mm in length and 10 mm in width to obtain test pieces. The refractive index nD of the obtained test pieces at 589 nm (D line) was measured using a multi-wavelength Abbe refractometer ("DR-M4 (circulating constant temperature water bath 60-C3)" manufactured by Atago Co., Ltd.) at a measurement temperature of 20°C and diiodomethane as a contact liquid. The measurement results are shown in Table 2.

[0083] The refractive indexes of the resin samples of Example 4 and Comparative Example 3 were measured as follows. The samples were hot-pressed at 200 to 240°C to form test pieces with a thickness of approximately 1 mm. The refractive index nD of these test pieces was measured at a wavelength of 587.6 nm (D-line) using a Kalnew Precision Refractometer "KPR-3000" (manufactured by Shimadzu Device Manufacturing Co., Ltd.) at a measurement temperature of 20°C, using a contact liquid with a refractive index of 1.69 as the contact liquid for the test pieces. Similarly, the refractive indices nC and nF were measured in the same manner as for the refractive index nD, except that the measurement wavelengths were changed to 656.3 nm (C-line) and 486.1 nm (F-line). The measurement results are shown in Table 3.

[0084] [Abbe number] Using the test piece for measuring the refractive index nD at 589 nm (D line), the refractive indices nF and nC were measured in the same manner as for the refractive index nD, except that the measurement wavelength was changed to 486 nm (F line) or 656 nm (C line). The Abbe number was calculated from the obtained refractive indices nF, nD, and nC at each wavelength using the following formula. (Abbe number) = (nD-1) / (nF-nC)

[0085] [Glass transition temperature Tg] Using a differential scanning calorimeter (Seiko Instruments Inc., "DSC 6220"), the sample was placed in an aluminum pan and Tg was measured in the range of 30°C to 200°C in accordance with JIS K7121.

[0086] [Evaluation results] [Table 2]

[0087] [Table 3] [Industrial Applicability]

[0088] The polyester resin according to this embodiment can be suitably used for, for example, optical lenses, optical films, optical sheets, pickup lenses, holograms, films for liquid crystal displays, and films for organic EL displays. Furthermore, the polyester resin according to this embodiment can be suitably used for, for example, paints, antistatic agents, inks, adhesives, pressure-sensitive adhesives, resin fillers, charging trays, conductive sheets, protective films (protective films for electronic devices, liquid crystal members, etc.), electric and electronic materials (carrier transport agents, light-emitting bodies, organic photosensitive bodies, thermosensitive recording materials, hologram recording materials), resins for electric and electronic parts or devices (optical disks, inkjet printers, digital paper, organic semiconductor lasers, dye-sensitized solar cells, EMI shielding films, photochromic materials, organic EL elements, color filters, etc.), resins for mechanical parts or devices (automobiles, aerospace materials, sensors, sliding members, etc.), etc.

Claims

1. A structural unit derived from a compound represented by the following formula (1), 【Chemistry 1】 [In the formula, R 1 ~R 4 two of which are hydrogen, R 1 ~R 4 The other two of 1-4 an alkyl ether group] a structural unit derived from a dicarboxylic acid compound; A polyester resin having the formula:

2. The formula (1) is the following formula (1-1): 【Chemistry 2】 [In the formula, R 1 ~R 4 is as described above. The polyester resin according to claim 1.

3. The dicarboxylic acid compound is at least one aromatic dicarboxylic acid compound selected from the group consisting of dicarboxylic acids represented by the following formula (2) and esters thereof; 【Transformation 3】 wherein Z is a monocyclic or polycyclic aromatic ring. At least one fluorene-based dicarboxylic acid compound selected from the group consisting of dicarboxylic acids represented by the following formula (3) and esters thereof; 【Chemistry 4】 [In the formula, X 1 are each independently C 1-8 an alkylene group] The polyester resin of claim 1 , comprising:

4. The polyester resin according to claim 3 , wherein Z in the formula (2) is a benzene ring, a naphthalene ring, or a binaphthalene ring.

5. a structural unit derived from the aromatic dicarboxylic acid compound; a structural unit derived from the fluorene-based dicarboxylic acid compound; The polyester resin according to claim 3, wherein the molar ratio of

6. A structural unit derived from an aliphatic diol compound represented by the following formula (4): 【Transformation 5】 [In the formula, X 2 is C 2-8 an alkylene group] The polyester resin of claim 1 further comprising:

7. A structural unit derived from a compound represented by formula (1), a structural unit derived from the aliphatic diol compound; 7. The polyester resin according to claim 6, wherein the molar ratio of

8. An optical film comprising the polyester resin according to any one of claims 1 to 7.

9. An optical lens comprising the polyester resin according to any one of claims 1 to 7.

10. A compound represented by the following formula (1), 【Transformation 6】 [In the formula, R 1 ~R 4 two of which are hydrogen, R 1 ~R 4 The other two of 1-4 an alkyl ether group] a dicarboxylic acid compound; A method for producing a polyester resin, comprising a polymerization step of reacting

11. The dicarboxylic acid compound is at least one aromatic dicarboxylic acid compound selected from the group consisting of dicarboxylic acids represented by the following formula (2) and esters thereof; 【Transformation 7】 wherein Z is a monocyclic or polycyclic aromatic ring. At least one fluorene-based dicarboxylic acid compound selected from the group consisting of dicarboxylic acids represented by the following formula (3) and esters thereof; 【Transformation 8】 [In the formula, X 1 are each independently C 1-8 an alkylene group] The method of claim 10, comprising:

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