JP2843215B2 - Polyester polymer, molded product thereof, and method for producing molded product - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyester copolymer, and more particularly, it is excellent in transparency and heat resistance, has small optical anisotropy, and has excellent moldability. The present invention relates to a polyester copolymer that can be suitably used.

[0002]

2. Description of the Related Art In recent years, plastics have been actively applied to optical materials. Polymethyl methacrylate (hereinafter, PMMA) and polycarbonate (hereinafter, PC) are practically used as lenses and are commercially available. PCs are increasingly used to reduce the weight of transparent components in automobiles. In the field of optical recording, optical disks for recording and reproducing information such as sound, images, characters, and the like using laser light have been rapidly developed and sold. The base material is PMM
A, PC and other amorphous polyolefins (hereinafter referred to as AP
O) etc. are used.

[0003] Optical materials are required to have excellent transparency and heat resistance and to have low optical anisotropy. PMMA is excellent in transparency, has low optical anisotropy, but has high hygroscopicity, has a drawback of easily deforming such as warpage when formed into a molded product, and has insufficient heat resistance. PC has high heat resistance and excellent transparency, but has poor moldability and high optical anisotropy. APO has low optical anisotropy and is excellent in heat resistance and dimensional stability, but is not satisfactory in moldability and is expensive.

Polyester copolymers have also been proposed as materials for optical applications (JP-A-57-20864, JP-A-2-98845, JP-A-2-3842).
No. 8). However, these resins are not always satisfactory because of insufficient heat resistance and insufficient optical characteristics.

Japanese Patent Application Laid-Open No. Hei 3-168221 discloses 9,9-bis (4-hydroxyphenyl) fluorene,
Various polyesters comprising 2,2-bis (4-hydroxyphenyl) propane, terephthalic acid, and isophthalic acid have been proposed. The glass transition points of these materials are high enough,
It is also reported that the optical anisotropy when the film is evaluated for stretching is small. However, there is a problem that optical anisotropy due to stress distortion and molecular orientation of a molded product of an injection-molded substrate becomes large.To reduce these, the fluidity of the resin is improved, and a high resin temperature and Injection molding must be performed under high mold temperature conditions, and there are problems such as decomposition and coloring of the polymer and sink of the molded product, which are not always satisfactory.

In Japanese Patent Publication No. 4-22931, an aliphatic dicarboxylic acid is added to an acid component in addition to an aromatic dicarboxylic acid to improve the mechanical properties of a resin to form a film. However, there is no description of an attempt to use it as an optical material.

[0007] Similarly, in Japanese Patent Application Laid-Open No. 3-73902, an aliphatic dicarboxylic acid is added to an acid component to improve mechanical properties. Although there is a description of the optical anisotropy (birefringence) of the film formed by casting, there is no description in the case of injection molding, and it cannot be said that molding is still sufficient.

Further, both polyester materials disclosed in JP-B-4-22931 and JP-A-3-73902 have a phenolic hydroxyl group and a carboxyl group directly bonded to each other. It is easily decomposed and does not have sufficient moisture resistance.

[0009]

An object of the present invention is to provide a polyester polymer having excellent transparency, heat resistance, small optical anisotropy, and excellent moldability and dimensional stability. It is in.

[0010]

Means for Solving the Problems The present inventors have made intensive studies to achieve the above object, and as a result, the specific polyester polymer is transparent, heat-resistant, and has a low optical anisotropy. They were found to be small and excellent in moldability and dimensional stability, and completed the present invention.

That is, the present invention relates to an aromatic dicarboxylic acid or a diester derivative thereof and a compound represented by the general formula (1):

Embedded image (R ₁ is an alkyl group having 2 to 4 carbon atoms, R ₂ , R ₃ , R
₄ and R ₅ are each independently hydrogen or an alkyl group having 1 to 4 carbon atoms) and a polyether for an optical material comprising an aliphatic glycol having 2 to 4 carbon atoms.
Steroid polymer, dihydroxylation represented by general formula (1)
The compound is at least 10 mol% of the total glycol components in the resin.
A certain polyester polymer for optical material, and intrinsic viscosity
(Phenol 60% by weight, 1,1,2,2-tetrac
In a mixed solution of 40% by weight of loroethane at 20 ° C)
0.3 or more of the polyester polymer for an optical material is provided.
To offer. The present invention also relates to the polyester polymerization
Molding for optical body, and said optics by injection molding
It is intended to provide a method for producing a molded article for use.

Hereinafter, the present invention will be described in detail. The polyester for an optical material of the present invention comprises an aromatic dicarboxylic acid or a diester derivative thereof and a compound represented by the general formula (1):

Embedded image (R ₁ is an alkyl group having 2 to 4 carbon atoms, R ₂ , R ₃ , R
₄ and R ₅ are each independently a hydrogen or an alkyl group having 1 to 4 carbon atoms) and a polyester polymer for an optical material comprising an aliphatic glycol having 2 to 4 carbon atoms.

[0013] dihydroxy compound represented by the general formula of the polyester (1) is small, the optical disk is easily deformed by heat, it has insufficient heat resistance, since the large optical anisotropy, 10 moles %
Good.

[0014] Poriesueru polymers of the present invention, 60% by weight phenol, 1,1,2,2, - mixed solution of 40% by weight tetrachloroethane, with an intrinsic viscosity measured at 20 ° C. of 0.3 or more preferably Rukoto Oh, and more preferably from 0.4 to 0.8. If the value is 0.3 or more,
Excellent mechanical strength, and below 0.8, the molecular orientation during molding
This is because the flow rate of the molded article is small and the molded article has good fluidity.

In the present invention, the aromatic dicarboxylic acid is
Examples thereof include terephthalic acid and isophthalic acid, and terephthalic acid is particularly preferable.

In the present invention, the dihydroxy compound represented by the general formula (1) is 9,9-bis- (4-hydroxyethoxyphenyl) -fluorene, 9,9-bis-
(4-hydroxypropoxyphenyl) -fluorene,
9,9-bis- (4-hydroxybutoxyphenyl)-
There are fluorene and the like, and 9,9-bis- (4-hydroxyethoxyphenyl) -fluorene is particularly preferable.

9,9-Bis- (4-hydroxyethoxyphenyl) -fluorene is, for example, 9,9-bis-
It is obtained by adding ethylene oxide (hereinafter referred to as EO) to (4-hydroxyphenyl) -fluorene. On this occasion,
In addition to the 2EO adduct (9,9-bis- (4-hydroxyethoxyphenyl) -fluorene) in which ethylene oxide is added one molecule at a time to both hydroxyl groups of phenol, a 3EO adduct, which is further added in a few molecule excess, 4EO Impurities such as adducts may be included. When impurities such as 3EO and 4EO are increased, the heat resistance of the polyester polymer is lowered. At this time, the purity of the 2EO adduct was 85.
% Or more, but preferably 95% or more.

9,9-bis- (4-hydroxypropoxyphenyl) -fluorene and 9,9-bis- (4-hydroxybutoxyphenyl) -fluorene are, for example,
It can be obtained by reacting 9,9-bis- (4-hydroxyphenyl) -fluorene with 3-chloro-propan-1-ol and 4-chloro-propan-1-ol, respectively, under alkaline conditions. The purity at this time may be 85% or more, preferably 95% or more.

In the present invention, the aliphatic glycol is ethylene glycol, 1,3-propanediol, 1,2
-Propanediol, 1,4-butanediol 1,2-
Examples thereof include butanediol and 1,3-butanediol. Among them, ethylene glycol and 1,4-butanediol are preferable, and ethylene glycol is particularly preferable.

The polyester copolymer comprising the aromatic dicarboxylic acid or its diester derivative, the dihydroxy compound represented by the general formula (1) and the aliphatic glycol having 2 to 4 carbon atoms according to the present invention can be prepared by, for example, a transesterification method. It can be manufactured by selecting an appropriate method from known methods such as a melt polymerization method such as a direct polymerization method, a solution polymerization method, and an interfacial polymerization method. The reaction conditions for the polymerization catalyst and the like at this time may be the same as those in the related art, and a known method can be used.

In solution polymerization, interfacial polymerization and the like, acid chloride is generally used as an active species of an acid component, and methylene chloride, chloroform and the like are used as a solvent. When a polyester copolymer is used as an optical disk or a magneto-optical disk, a metal thin film such as a reflective film or a recording film is fixed to the substrate by a method such as vapor deposition and sputtering. Corrodes the film and recording film,
Since the life and reliability of an optical disk or a magneto-optical disk are reduced, a sufficient step of removing residual chlorine such as washing and filtration is required. As a polymerization method, a transesterification method in which chlorine is not mixed is more preferable.

In order to produce the polyester polymer of the present invention by the transesterification method, the dihydroxy component represented by the general formula (1) preferably accounts for 10 to 95 mol% of the glycol component in the resin. This is not a multi-than 95 mol%
In such a case , the melt polymerization reaction may not proceed or a sufficient degree of polymerization may not be easily achieved. Therefore, it is preferable to use a solution polymerization method or an interfacial polymerization method .

In the case of molding an optical material from the polyester copolymer for an optical material of the present invention, a step of starting a raw material charging step, a polymerization reaction, and a step of extruding the copolymer into a refrigerant to form a pellet or a sheet. Therefore, it is desired to take care that dust and the like do not enter. This cleanness is
Usually, it is 1000 or less for compact discs, and 100 or less for more advanced information recording.

Injection compression molding machines are usually well suited for molding optical disk substrates, and the molding conditions are particularly important for the mold surface temperature and the resin temperature. Although it cannot be specified unconditionally depending on the composition of the dihydroxy component and the degree of polymerization, the mold surface temperature is preferably from 50 ° C to 160 ° C, and the resin temperature at this time is preferably from 250 ° C to 350 ° C. good. When the mold surface temperature is 250 ° C. or lower, both the fluidity and transferability of the resin are poor, stress strain remains during injection molding, and the birefringence tends to increase. Not economic. Mold temperature is 160 ℃
When the value exceeds , the transferability is good, but it tends to be deformed when releasing. On the other hand, if the resin temperature exceeds 350 ° C., decomposition of the resin is liable to occur, which causes a reduction in the strength of the molded product and causes coloring, which is not preferable.

[0025]

As described above, the optical material of the present invention can provide an optical material having good transparency and heat resistance, excellent moldability, dimensional stability and chemical resistance, and is industrially useful. Things. Further, an optical disk substrate made of this material has low optical anisotropy and is industrially useful.

[0026]

The present invention will be specifically described below with reference to examples. The intrinsic viscosity, glass transition temperature, birefringence, total light transmittance , and transferability evaluation of the copolymers in the examples were measured by the following methods.

(1) Intrinsic viscosity The copolymer 0.1 was added to 50 ml of a mixed solution of 60% by weight of phenol and 40% by weight of 1,1,2,2-tetrachloroethane.
After dissolving 15 to 0.5 g at 80 ° C, the viscosity was measured and determined at 20 ° C.

(2) Glass Transition Temperature About 10 mg of a sample was measured using a differential scanning calorimeter (Rigaku Denki DSC-8230) at a heating rate of 10 ° C./min. The glass transition temperature Tmg and the extrapolated glass transition temperature end temperature Teg were determined as defined in JIS K ^7121-1987 .

(3) Birefringence A Clarmont, Berek, and Brace Keller compensator were mounted on a polarizing microscope of the Carl Zeiss company.
The measurement was performed using monochromatic light of 46 nm.

(3-1) Evaluation on Film A resin was melted at 260 to 300 ° C. and extruded to form a disc-shaped test piece having a diameter of 30 mm and a thickness of 1 mm. Press molding was performed at 240 ° C. to obtain a film having a thickness of 80 to 150 μ. The obtained film was cut into a strip of 4 × 40 mm to obtain a measurement test piece. Extrapolated glass transition end temperature The test specimen was stretched at 10% / sec by 40% at a temperature of Teg + 1 ° C., and then rapidly cooled to obtain a stretched film. The birefringence of these films was measured.

(3-2) Evaluation on Disk Thickness 1.2 mm, diameter 12 molded by injection compression molding machine
The retardation at a position 50 mm in the radial direction from the center of the 0 mm disk was measured.

(4) Total light transmittance A self-recording spectrophotometer (Hitachi U-
3400) in the wavelength range of 400 to 900 n, and the average value was shown.

(5) Evaluation of transferability Thickness 1.0 mm, 80 mm molded by injection compression molding machine
The groove shape of a φ disk plate (one side was a mirror surface, one side was a groove groove (a spiral having a spacing of 1.4 μm, a depth of 0.09 μm, and a width of 0.5 μm)) was evaluated with a microscope.

Hereinafter, "parts" in the examples means parts by weight. Example 1 38 parts of dimethyl terephthalate, 9,9-bis- (4-
(Hydroxyethoxyphenyl) -fluorene 35 parts,
Using 27 parts of ethylene glycol as a raw material, as a catalyst,
Using 0.042 parts of calcium acetate, these were charged into a reaction vessel, and stirred at 190 ° C. to 23 ° C. according to a conventional method.
The ester exchange reaction was performed by gradually heating to 0 ° C. After extracting a predetermined amount of methanol out of the system, 0.012 parts of germanium oxide, which is a polymerization catalyst, and 0.033 of trimethyl phosphate to prevent coloring, are added, and the temperature and pressure are gradually increased. The temperature of the heating tank is 280 ° C and the degree of vacuum is 1 Torr while removing ethylene glycol generated.
Get to: Maintaining this condition, waiting for the viscosity to rise, when the torque applied to the stirrer reaches a predetermined value,
The reaction was terminated, and the reaction product was extruded into water to obtain a pellet.

This copolymer had an intrinsic viscosity of 0.55 and a glass transition temperature of 124 ° C. The resin was melt molded at 290 ° C. to obtain a sample on a disk, and then pressed at 220 ° C. to obtain a 120 μm thick film. When stretched at 136 ° C., the birefringence was 41 × 10 ⁻⁴ . The disc obtained by injection molding at a mold temperature of 70 ° C. and a resin temperature of 280 ° C. had a retardation of 13 nm and a total light transmittance of 90%.

Example 2 The raw material composition was 26 parts of dimethyl terephthalate, 56 parts of 9,9-bis- (4-hydroxyethoxyphenyl) -fluorene and 18 parts of ethylene glycol, 0.028 parts of calcium acetate, and 0 parts of germanium oxide. .009
Parts and trimethyl phosphate were changed to 0.022 parts, and the process was carried out in the same manner to obtain pellets.

This copolymer had an intrinsic viscosity of 0.43 and a glass transition temperature of 150 ° C. The resin was melt molded at 290 ° C. to obtain a sample on a disk, and then pressed at 250 ° C. to obtain a 130 μm thick film. When stretched at 161 ° C., the birefringence was 12 × 10 ⁻⁴ . The disc obtained by injection molding at a mold temperature of 100 ° C. and a resin temperature of 310 ° C. had a retardation of 8 nm and a total light transmittance of 90%.

Examples 3 to 6, Comparative Example 1 After obtaining pellets in the same manner as in Example 1 except that the raw material composition ratio was changed, the resin was melt-molded at 260 to 310 ° C. After it was obtained, it was pressed at 220 to 250 ° C. to obtain a film having a thickness of 100 to 130 μ. In addition, a disk was obtained by injection molding at a mold temperature of 70 to 110 ° C and a resin temperature of 260 to 310 ° C. The results are shown in Table 1 .

Comparative Example 2 A commercially available optical disk grade polycarbonate resin was melt molded at 300 ° C. to obtain a sample on a disk.
Pressing was performed at 240 ° C. to obtain a 120 μm thick film.
When stretched at 148 ° C., the birefringence was 168 × 10 ⁻⁴ . The retardation of a disk obtained by injection molding at a mold temperature of 100 ° C. and a resin temperature of 310 ° C. is 30.
nm and the total light transmittance was 90%.

As is clear from Table 1 , Comparative Example 1 is not preferable as an optical material because it has low heat resistance, has crystallinity, and adversely affects moldability, thermal stability, and transparency. In Comparative Example 2, although generally used polycarbonate resin, it has a large optical anisotropy and may have a problem in moldability.

From the above, the optical material of the present invention has excellent transparency, heat resistance, excellent moldability, dimensional stability and chemical resistance, low optical anisotropy, and excellent optical properties. It turns out that it is a material.

[0042]

[Table 1]

──────────────────────────────────────────────────続 き Continued on the front page Examiner Satoshi Morikawa (56) References JP-A-3-73902 (JP, A) JP-A-3-281524 (JP, A) JP-A-63-152622 (JP, A) 57-192432 (JP, A) JP 4-22931 (JP, B2) (58) Field surveyed (Int. Cl. ⁶ , DB name) C08G 63/12-63/676

Claims (10)

(57) [Claims] 1. An aromatic dicarboxylic acid or a diester derivative thereof and a compound represented by the general formula (1): (R ₁ is an alkyl group having 2 to 4 carbon atoms, R ₂ , R ₃ , R
_4, and R ₅ is a dihydroxy compound represented by independently hydrogen or C 1 -C 4 alkyl group), a polyester polymer for optical science material carbon atoms ing from aliphatic glycols from 2 4. 2. Dihydroxylation represented by the general formula (1)
The compound is at least 10 mol% of the total glycol components in the resin.
The polyester polymer for an optical material according to claim 1. 3. Intrinsic viscosity (phenol 60% by weight, 1,
Mixed solution of 40% by weight of 1,2,2-tetrachloroethane
(Measured in liquid at 20 ° C.) is 0.3 or more
The polyester material for an optical material according to claim 1 or 2,
Coalescing. 4. A polyester polymer for an optical material according to claim 1-3 in which the aromatic dicarboxylic acid is characterized in that the terephthalic acid. 5. The method according to claim 1, wherein the dihydroxy compound represented by the general formula (1) is 9,9-bis- (4-hydroxyethoxyphenyl) -fluorene.
The polyester polymer for an optical material according to any one of the above . 6. aliphatic glycols optical material for polyester polymer according <br/> to claim 1-5, characterized in that the ethylene glycol. 7. The resin according to claim 1, wherein the molar ratio of the dihydroxy compound represented by the general formula (1) to the aliphatic glycol having 2 to 4 carbon atoms in the resin is from 10:90 to 95: 5. 7. The polyester polymer for an optical material according to any one of items 1 to 6 . 8. An optical molded article comprising the polyester polymer according to claim 1. 9. An optical disk substrate comprising the polyester polymer according to claim 1. 10. A method for producing a molded article for optical use, comprising injection-molding the polyester polymer according to claim 1.