JPH07188401A - Polyester polymer and molded product thereof - Google Patents

Abstract

PURPOSE:To provide a novel polyester polymer having very small optical anisotropy and excellent moldability and dimensional stability by using an aliph. dicarboxylic acid, a particular dihydroxy compd., and an aliph. glycol. CONSTITUTION:This polyester polymer comprises an aliph. dicarboxylic acid (e.g. malonic acid or succinic acid) or its ester forming derivative, a dihydroxy compd. of the formula (wherein R1 represents a C2 to C4 alkylene group and R2 to R5 may be the same or different and represent each H or a C1 to C4 alkyl, aryl, or aralkyl group), e.g. 9,9-bis[4-(2-hydroxyethoxy)phenyl]-fluorene, and a C2 to C4 aliph. glycol. It has an intrinsic viscosity (as measured at 20 deg.C in a mixed solution of 60wt.% phenol and 40wt.% 1,1,2,2-tetrachloroethane) of not less than 0.3. Preferably, the polyester polymer is molded into a disk substrate, lens, sheet, film, tube, and fiber.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyester polymer and a molded product thereof, and more specifically, it has excellent transparency and heat resistance, has a very small optical anisotropy and is excellent in moldability and is an engineering plastic. In addition, the present invention relates to a polyester polymer containing 9,9-bis [4- (2-hydroxyethoxy) phenyl] fluorene, which is particularly suitable as a material for optical devices, and a molded product thereof.

[0002]

2. Description of the Related Art Conventionally, resins which are transparent and have excellent mechanical properties have been widely used as optical materials as engineering plastics. For example, polymethylmethacrylate (hereinafter abbreviated as PMMA) and polycarbonate (hereinafter P
(Abbreviated as C) and the like are used as optical materials for compact discs, laser discs, lenses, etc., and for transparent parts of automobiles. PMMA is often used because it has excellent transparency and small optical anisotropy, but it has high hygroscopicity and is liable to be deformed such as warp after molding and has poor morphological stability. On the other hand, PC has high heat resistance and excellent transparency, but it has problems such as poor fluidity and large birefringence of the molded product, and it cannot be said that it is sufficiently satisfactory as an optical material. Furthermore, in recent years, optical discs that record and reproduce information such as voice, images and characters using laser light have been rapidly developed,
There is a demand for a substrate material having higher performance optical characteristics.

Polyester copolymers have also been proposed as optical materials (Japanese Patent Publication No. 57-20864, Japanese Patent Publication No. 2-98845, Japanese Patent Publication No. 2-38428). However, these resins are not always satisfactory because they have insufficient optical characteristics.

Further, in Japanese Examined Patent Publication No. 3168121, 9,9-bis (4-hydroxyphenyl) fluorene,
Various polyesters composed of 2,2-bis (4-hydroxyphenyl) propane, terephthalic acid and isophthalic acid have been proposed. It is reported that the glass transition point of these resins is sufficiently high and the optical anisotropy when the film is stretched and evaluated is small. Further, U.S. Pat. No. 3,546,165 discloses that a polymer of 9,9-bis (4-hydroxyphenyl) fluorene and terephthalic acid or isophthalic acid can be obtained by the acid chloride method. To improve the moldability of this material, Japanese Patent Publication No. 4-22931
The publication discloses a heat resistant polyester using a mixture of 9,9-bis (4-hydroxyphenyl) fluorene, terephthalic acid, isophthalic acid and a fatty acid in a specific ratio.

However, these are all 9,9-bis (4-
(Hydroxyphenyl) fluorene is used,
The polymerization method at that time also requires special conditions. That is 9, 9
-Since there is a phenolic group at both ends of -bis (4-hydroxyphenyl) fluorene, it is very difficult to react unlike aliphatic alcohol, and therefore reaction at a higher temperature in the melt polymerization method. Conditions are required, and the thermal decomposition of the resulting polymer is likely to occur, resulting in coloration and poor quality. In addition, after the terminal group on the dicarboxylic acid side is converted to acid chloride, a uniform reaction is difficult under the conditions of using a polymerization method of dehydrochlorination in a solvent, and therefore, a compound having a large molecular weight distribution is generally obtained. It is said that the post-treatment of a large amount of the required catalyst compound is required, which complicates the manufacturing method and increases the cost. In addition, despite various improvements, the material obtained has a too high glass transition point, making injection molding difficult and moldability still unsatisfactory.

[0006]

DISCLOSURE OF INVENTION Problems to be Solved by the Invention As a result of intensive studies made by the present inventors in view of the drawbacks of the prior art, a new polyester polymer was found, and the present invention was completed. However, we provide a polyester copolymer that is excellent in transparency, mechanical and electrical properties, has extremely small optical anisotropy, and has excellent moldability and dimensional stability, and is suitable for engineering plastics, especially optical materials. There is. Still another object is to provide a polyester polymer and a molded product thereof which can be easily manufactured at low cost by industrial production.

[0007]

Means for Solving the Problems The above-mentioned object is to provide an aliphatic dicarboxylic acid or an ester-forming derivative thereof with a compound represented by the general formula (1):

[Chemical 2] (R ₁ is an alkylene group having 2 to 4 carbon atoms, R ₂ , R ₃ ,
R ₄ and R ₅ are hydrogen or an alkyl group having 1 to 4 carbon atoms, an aryl group, or an aralkyl group, which may be the same or different, and
A substantially linear polyester polymer comprising an aliphatic glycol having 2 to 4 carbon atoms, wherein the polyester polymer has an intrinsic viscosity (phenol 60% by weight, 1,
It is achieved by a polyester polymer characterized in that a 1,2,2, -tetrachloroethane 40% by weight mixed solution has a value of 0.3 or more) (measured at 20 ° C.).

The present invention will be described in detail below. As described above, the polyester polymer of the present invention contains the aliphatic dicarboxylic acid or its ester-forming derivative and the compound represented by the general formula (1)

[Chemical 3] (R ₁ is an alkylene group having 2 to 4 carbon atoms, R ₂ , R ₃ ,
R ₄ and R ₅ are hydrogen or an alkyl group having 1 to 4 carbon atoms, an aryl group or an aralkyl group, which may be the same or different) and a dihydroxy compound represented by It is a substantially linear polyester polymer composed of 2 to 4 aliphatic glycols.

The polyester polymer of the present invention has a glass transition temperature (Tg) of 70 ° C. to 12 from the viewpoint of the fluidity of the melt.
It is necessary to have an intrinsic viscosity of 0.3 or more at 0 ° C. And by changing the composition of 9,9-bis [4- (2-hydroxyethoxy) phenyl] fluorene according to the use,
It is possible to obtain an appropriate molded body. If the ratio of this dihydroxy compound to the total dihydroxy component is small, the molded body is likely to be deformed by heat, the heat resistance is lowered, and the stability of the molded body tends to be lowered.

The general formula (1) of the polyester

[Chemical 4] The use of a dihydroxy compound represented by and an aliphatic dicarboxylic acid as a copolymerization component is a key part of the present invention. With this combination, the optical anisotropy is obtained without impairing the moldability of the polyethylene terephthalate resin. It was found that the sex is reduced. For reduction of optical anisotropy,
The reason is not clear, but it is presumed that the particular molecular structure, that is, the structure in which the fluorene group is arranged in the vertical plane with respect to the main chain direction having two phenol groups, is considered to be due to this. Further, it is generally known that when an aromatic dicarboxylic acid such as terephthalic acid or isophthalic acid enters the main chain direction, the heat resistance is improved, but the optical anisotropy is increased. Therefore, the optical anisotropy was further reduced by using an aliphatic dicarboxylic acid. The magnitude of this optical anisotropy can be known by measuring the birefringence in a molded product molded using a polymer material. The birefringence of the molded product of this material is almost zero. This is a particularly important condition when forming an optical disk substrate, which is a high-density recording medium, particularly a magneto-optical disk.
The ratio (C is carrier: recording signal, N is noise: noise) can be reduced.

The polyester polymer of the present invention has an intrinsic viscosity of 0.3 or more measured at 20 ° C. in a mixed solution of 60% by weight of phenol and 40% by weight of 1,1,2,2-tetrachloroethane. , Preferably 0.4 to 0.8. If the intrinsic viscosity is less than 0.3, the mechanical strength of the molded product will be insufficient. However, if the intrinsic viscosity is 0.3 or more, a molded product having sufficient mechanical strength can be obtained. As the intrinsic viscosity increases, stress strain and molecular orientation are more likely to occur during molding, and thus the birefringence of the molded product tends to increase. For example, in molding an optical disk substrate, the intrinsic viscosity is lower than 0.35 to 0.
55, and those having a higher value of 0.6 to 0.8 for blow molding may be appropriately selected depending on the intended use. The polyester polymer having the desired intrinsic viscosity can be easily obtained by adjusting the polymerization conditions such as the molecular weight modifier, the polymerization time and the polymerization temperature.

Examples of the aliphatic dicarboxylic acid or the ester-forming derivative thereof used for the polyester polymer of the present invention include malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid and methyl. Examples thereof include malonic acid, ethylmalonic acid, methylsuccinic acid, 2,2-dimethylsuccinic acid, 2,3-dimethylsuccinic acid, 3-methylglutaric acid, 3,3-dimethylglutaric acid, and the like, and aliphatic dicarboxylic acids or ester-forming derivatives thereof. These may be used alone or in combination of two or more as required. However, when the number of methylene groups in the aliphatic dicarboxylic acid is large, the glass transition point becomes low. Therefore, in the present invention, the number of methylene groups in the aliphatic dicarboxylic acid is preferably 6 or less, more preferably 3 or less.

In the present invention, examples of the dihydroxy compound represented by the general formula (1) include 9,9-bis [4- (2-hydroxyethoxy) phenyl] fluorene and 9,9-bis [4- ( 2-hydroxyethoxy)-
3-methylphenyl] fluorene, 9,9-bis [4-
(2-Hydroxyethoxy) -3,5-dimethylphenyl] fluorene, 9,9-bis [4- (2-hydroxyethoxy) -3-ethylphenyl] fluorene, 9,9
-Bis [4- (2-hydroxyethoxy) -3,5-diethylphenyl] fluorene, 9,9-bis [4- (2
-Hydroxyethoxy) -3-propylphenyl] fluorene, 9,9-bis [4- (2-hydroxyethoxy) -3,5-dipropylphenyl] fluorene, 9,
9-bis [4- (2-hydroxyethoxy) -3-isopropylphenyl] fluorene, 9,9-bis [4-
(2-Hydroxyethoxy) -3,5-diisopropylphenyl] fluorene, 9,9-bis [4- (2-hydroxyethoxy) -3-n-butylphenyl] fluorene, 9,9-bis [4- (2 -Hydroxyethoxy)-
3,5-di-n-butylphenyl] fluorene, 9,9
-Bis [4- (2-hydroxyethoxy) -3-isobutylphenyl] fluorene, 9,9-bis [4- (2-
Hydroxyethoxy) -3,5-diisobutylphenyl] fluorene, 9,9-bis [4- (2-hydroxyethoxy) -3- (1-methylpropyl) phenyl] fluorene, 9,9-bis [4- (2 -Hydroxyethoxy) -3,5-bis (1-methylpropyl) phenyl]
Fluorene, 9,9-bis [4- (2-hydroxyethoxy) -3-phenylphenyl] fluorene, 9,9-
Bis [4- (2-hydroxyethoxy) -3,5-diphenylphenyl] fluorene, 9,9-bis [4- (2
-Hydroxyethoxy) -3-benzylphenyl] fluorene, 9,9-bis [4- (2-hydroxyethoxy) -3,5-dibenzylphenyl] fluorene, 9,
9-bis [4- (3-hydroxypropoxy) phenyl] fluorene 9,9-bis [4- (4-hydroxybutoxy) phenyl] fluorene and the like can be mentioned, and these can be used alone or in combination of two or more kinds. Is also good. Among these, 9,9-bis [4- (2-hydroxyethoxy) phenyl] fluorene is the most preferable in terms of optical characteristics and moldability.

For example, 9,9-bis [4- (2-hydroxyethoxy) phenyl] fluorene is obtained by adding ethylene oxide (hereinafter abbreviated as EO) to 9,9-bis (4-hydroxyphenyl) fluorene. Obtained. At this time, ethylene oxide is 1 in both hydroxyl groups of phenol.
2EO adducts (9,9-bis [4-
In addition to (2-hydroxyethoxy) phenyl] fluorene), 3EO adduct obtained by further adding a few molecules in excess, 4
Impurities such as EO adducts may be contained. 3EO, 4
If the amount of impurities such as EO increases, the heat resistance of the polyester polymer will decrease. At this time, the purity of the 2EO adduct may be 85% or more, preferably 95% or more.

In the present invention, as the aliphatic glycol, ethylene glycol, 1,3-propanediol,
1,2-propanediol, 1,4-butanediol,
1,2-butanediol, 1,3-butanediol,
Examples thereof include glycols such as 1,5-pentanediol, 1,4-pentanediol, 1,3-pentanediol, and alicyclic dimethanols such as cyclohexanedimethanol and cyclopentanedimethanol. Among them, ethylene glycol, 1,4-butylene glycol is preferable, and ethylene glycol is particularly preferable from the viewpoint of heat resistance. These may be used alone or in combination of two or more.

If desired, a dihydroxy compound having an aromatic ring in its main chain and side chain, such as 1,1-bis [4- (2-hydroxyethoxy) phenyl] -1-phenylethane, bis [4- ( A compound having an aromatic ring and sulfur in the main chain such as 2-hydroxyethoxy) phenyl] sulfone, or at least one other dihydroxy compound may be used in combination in an amount of 10 mol% of the total diol component.

The polyester polymer of the present invention is, for example,
It can be produced by selecting an appropriate method from known methods such as a transesterification method, a melt polymerization method such as a direct polymerization method, a solution polymerization method and an interfacial polymerization method. The reaction conditions of the polymerization catalyst and the like at that time may be the same as in the conventional case, and a known method can be used.

When a solution polymerization method, an interfacial polymerization method or the like is adopted in producing the polyester polymer of the present invention, acid chloride is generally used as an active species of an acid component, or methylene chloride or chloroform is used as a solvent. Etc., but chlorides and catalyst compounds that are by-products remain in the polymer, and this is generally not good for the quality of the product, so it is generally necessary to remove residual foreign substances after the polymerization step. . These are sheets, films, plates,
It lowers the operability in the molding process of fibers and the like, and also deteriorates the quality of the obtained molded body. For example, a large amount of thermal decomposition occurs during high temperature heating. When used as an optical material, a metal thin film such as a reflective film or a recording film is fixed to a plate or a substrate by a method such as vapor deposition or sputtering. However, when a large amount of chlorine is contained, the reflective film or the recording film is formed. Since it corrodes and reduces the life and reliability of the product, sufficient steps such as cleaning and filtering to remove residual foreign substances are necessary.

The polyester polymer of the present invention is particularly good when the melt polymerization method is used. That is, the compound of 9,9-bis [4- (2-hydroxyethoxy) phenyl] fluorene has a terminal group having a property very similar to that of an aliphatic glucose and has high reactivity. This is 9,9-bis (4-
It is significantly different from (hydroxyphenyl) fluorene. For this reason, there is no need to use a raw material called acid chloride, and therefore a production method that is essentially chlorine-free is possible, and the amount of catalyst used can be reduced under reaction conditions at high temperatures, and a method that has less residual foreign matter is possible. Became.

In order to produce the polyester polymer of the present invention by the transesterification method of the melt polymerization method, the dihydroxy component represented by the general formula (1) is 4 of the glycol component in the resin.
It is preferably 0 to 95 mol%. This is 95
If it is more than mol%, problems such as that the melt polymerization reaction does not proceed or the polymerization time becomes extremely long may occur. When the content is more than 95 mol%, it can be produced by a solution polymerization method or an interfacial polymerization method although there are problems in the above-mentioned steps. If it is less than 40 mol%, the glass transition point of the resin is lowered.

The polyester polymer of the present invention comprises a lubricant, a heat-resistant agent, an antistatic agent, an ultraviolet absorber, and
A pigment or the like can be added. When the polyester polymer of the present invention is used for an optical material, starting the raw material charging step, the polymerization step, the step of pelletizing the polymer,
Care should be taken to prevent dust from entering during injection molding or the step of molding into a sheet or film. In such a case, a class 1000 or less is preferable for a normal compact disc (hereinafter referred to as a CD), and a class 100 or less for a more advanced information recording.

Since the polyester polymer of the present invention is amorphous, it has excellent transparency, and since it has excellent melt viscoelastic properties, it has excellent moldability, and residual stress strain and molecular orientation occur during molding. In addition to being difficult, even if they remain, it has a property that the optical anisotropy is extremely small. Therefore, the transparent material and the optical material are extremely useful and well suited resins.

The polyester polymer molding of the present invention is prepared by using the above-mentioned polyester polymer by a conventionally known molding method, for example,
Injection molding, injection compression molding, transfer molding,
It can be obtained by a blow molding method, an extrusion molding method, a pressure molding method, a casting molding method, or the like. Upon molding, a more suitable molding method may be selected from these molding methods. For example, for optical disk substrates, lenses, general molded parts, etc., injection molding method and injection compression molding method are well compatible, and film, sheet, optical fiber, The extrusion molding method is suitable for fibers and the like. Blow molding is suitable for bottles and bags, and pressure molding and transfer molding are suitable for molding. Among them, the excellent properties of the polyester polymer of the present invention, transparency, low optical anisotropy, a molded product that requires heat resistance, that is, an injection compression molding method and an extrusion molding method are used to obtain an optical molded product. preferable.

An injection compression molding machine is well suited for molding an optical disk substrate, which is an example of an optical molded body, and by appropriately selecting molding conditions such as resin temperature, mold temperature and holding pressure, the disk substrate An excellent product having a small birefringence, an extremely uniform birefringence in the radial direction of the disk substrate, a thickness, a transfer property, and no warping can be obtained. Such molding conditions vary depending on the composition, the degree of polymerization, etc. and cannot be specified unconditionally, but the mold temperature is 20 ° C. or lower of the heat distortion temperature, that is, 60 ° C. or higher 10
It is preferably 0 ° C or lower. The resin temperature is 240 ° C or higher 3
It is preferably 60 ° C or lower. If the temperature is lower than 240 ° C., the fluidity and transferability of the resin deteriorate, and stress strain remains during molding to increase birefringence. On the other hand, if the temperature exceeds 360 ° C., thermal decomposition of the resin is likely to occur, which may cause deterioration of the strength of the molded product and coloring, and further, contamination of the mirror surface of the mold and stamper, and deterioration of the releasability.

[0025]

EXAMPLES The present invention will be specifically described with reference to the following examples. The intrinsic viscosity, glass transition temperature, and birefringence of the polymers in the examples were measured by the methods described below.

1. Intrinsic viscosity 60% by weight of phenol, 40% by weight of 1,1,2,2-tetrachloroethane in 50 ml of a mixed solution was added with the copolymer of 0.1%.
After melt | dissolving 15-0.5g at 80 degreeC, the viscosity was measured and determined at 20 degreeC.

2. Glass transition temperature About 10 mg of a sample was used for a differential scanning calorimeter (Rigaku Denki DSC-8230), and heating was performed at a temperature rising rate of 10 ° C./min for measurement. The glass transition temperature Tmg was determined according to JIS K 7121-1987.

3. Birefringence: A polarizing microscope manufactured by Carl Zeiss Co., Ltd., equipped with Ceralmon, Berek, and Brace Keller type compensator, 54
It was measured with 6 nm monochromatic light. The measurement piece is made of resin 240-3
Melt at 00 ° C, extrusion molding, diameter 30mm, thickness 1
mm-shaped disc-shaped test pieces are prepared, and the molded test pieces are press-molded at 160 to 240 ° C. to have a thickness of 80 to 150.
A film of μ was obtained. The resulting film is 4 x 40 mm
Was cut into strips to obtain measurement test pieces. Tmg + 10
The measurement test piece was stretched at 40% at 20% / sec at a temperature of ° C and then rapidly cooled to obtain a stretched film. The birefringence of these films was measured.

4. NMR Using an FT-NMR apparatus manufactured by Varian (300 MHz), a sample is dissolved in a mixed solvent (1: 1) of trifluoroacetic acid and chloroform, and tetramethylsilane is mixed as a standard to measure a proton NMR spectrum. did.

Example 1 With respect to 1 mol of dimethyl succinate, 9,9-
Bis [4- (2-hydroxyethoxy) phenyl] fluorene (0.7 mol) and ethylene glycol (2.2 mol) were used as raw materials, and calcium acetate 0.000 was used as a catalyst.
8 mol and 0.0002 mol of manganese acetate were used, and these were put into a reaction vessel and stirred under a conventional method.
The ester exchange reaction was carried out by gradually heating from 0 ° C to 245 ° C. After extracting a predetermined amount of methanol out of the system, 0.012 mol of germanium oxide as a polymerization catalyst and trimethyl phosphate 0.003 in order to prevent coloring.
18 mol and then gradually raise the temperature and reduce the pressure. While removing the generated ethylene glycol, raise the heating bath temperature to 2
The degree of vacuum was set to 90 ° C. and reached 1 Torr or less. This condition was maintained, the increase in viscosity was waited, the reaction was terminated after reaching a predetermined stirring torque (after about 2 hours), and the reaction product was extruded into water to obtain pellets.

This resin was melt-molded at 240 ° C. to obtain a disk-shaped sample, which was then pressed at 220 ° C. to give a thickness of 12
A 0 μ film was obtained. When stretched at 101 ° C., the birefringence was -1 × 10 ^-4 . NM of the sample of Example 5
The R spectrum is shown in FIG.

[Figure 1]

Examples 2 to 4 Pellets were produced in the same manner as in Example 1 except that the raw material composition ratio was changed. The results are shown in Table 1. All were uniformly transparent.

[Table 1]

Comparative Example 1 Ethylene glycol was added to 1 mol of all dicarboxylic acids.
Pellets were obtained in the same manner as in Example 1 except that 2.2 mol, calcium acetate 0.0008 mol, germanium oxide 0.0024 mol, and phosphoric acid trimethyl ester 0.0036 mol were used. The evaluation results of this polymer are shown in Table 1. It was found that Tmg was low, the heat resistance was poor, and the birefringence was large, which was not suitable for optical use.

Comparative Example 2 2.2 mol of ethylene glycol and 0.000 of calcium acetate based on 1 mol of dimethyl terephthalate.
Pellets were obtained in the same manner as in Example 1 except that 08 mol, germanium oxide 0.0024 mol, and phosphoric acid trimethyl ester 0.0036 mol were used as raw material compositions and additives. The physical properties of the obtained polymer are shown in Table 1.
An attempt was made to evaluate the birefringence in the same manner as a film, but the film became cloudy and could not be measured. Although this polymer can be used for special purposes, it is not suitable for the purpose of the present invention, which has heat resistance and is required to have optical transparency.

Comparative Example 3 In Example 1, when the stirring torque was low (1 Torr
The reaction was completed about 30 minutes after reaching (1) and the reaction product was extruded into water, but no pellet was formed. When the intrinsic viscosity of this resin was measured, it was 0.25. Further, as a comparative example, a film was prepared in the same manner as in Example 1 using a commercially available polycarbonate (Novarex AD3 manufactured by Mitsubishi Kasei Kogyo Co., Ltd.) to evaluate birefringence. The results are also shown in Table 1. Comparison between these Examples and Comparative Examples revealed that the product of the present invention is optically transparent, has very small birefringence, and is excellent in moldability and the like.

[0036]

As described above, the polyester polymer of the present invention can provide a molding material having excellent transparency, small optical anisotropy, moldability, dimensional stability and chemical resistance. It can be seen that it is industrially useful for optical materials such as plastic lenses, optical fibers, optical discs, fibers, films and sheets.

[Brief description of drawings]

FIG. 1 is an NM of a sample according to the present invention obtained in Example 5.
It is an R spectrum diagram.

[Procedure amendment]

[Submission date] July 8, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be amended] Title of invention

[Correction method] Change

[Correction content]

Title: Polyester polymer and molded article thereof

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location G02B 6/00 391 // C08L 67:00

Claims (2)

[Claims] 1. An aliphatic dicarboxylic acid or its ester-forming derivative and a compound represented by the general formula (1): (R ₁ is an alkylene group having 2 to 4 carbon atoms, R ₂ , R ₃ ,
R ₄ and R ₅ are hydrogen or an alkyl group having 1 to 4 carbon atoms, an aryl group, or an aralkyl group, which may be the same or different, and
A substantially linear polyester polymer comprising an aliphatic glycol having 2 to 4 carbon atoms, wherein the polyester polymer has an intrinsic viscosity (phenol 60% by weight, 1,
A polyester polymer having a 1,2,2, -tetrachloroethane 40% by weight mixed solution of 0.3 or more). 2. A disc substrate, a lens, a sheet, a film, a tube, the polyester polymer according to claim 1.
Alternatively, a polyester molded product obtained by molding into a fiber.