JPH0652585B2 - Optical molded products - Google Patents

Description

The present invention relates to a molded article useful as an optical component in the field of optoelectronics such as an optical disc substrate, a plastic lens, a transparent electrode substrate for a display, etc.

[Conventional technology]

In recent years, various optoelectronic products utilizing the property of light in the field of information processing, such as an optical memory, a projection television, a liquid crystal, a display using an electroluminescence, etc., have been widely put into practical use. Various optical molded parts for optical transmission, such as optical disk substrates, plastic lenses, and transparent electrode substrates for display have begun to be used.

In the above various parts, it is strongly desired that the optical homogeneity (for example, the birefringence is small) and the deformation due to heat or moisture absorption be small. Particularly in an optical disk substrate, the difference in reflectance or transmittance is taken out as a signal output through the substrate, so that the quality of birefringence directly affects the signal-noise ratio. This problem is caused by a read-only optical disk, a permanent write optical disk,
This is common to erasable optical disks, optical cards, etc., but the effect is particularly remarkable in magneto-optical recording in which signals are read out by rotation of polarization (Kerr effect).

In addition, since the optical disk is used for writing and reading signals by narrowing the laser beam to 1 to 2 microns, the deformation of the substrate due to heat and moisture absorption should be minimized from the viewpoint of focus control.
It is necessary to have heat resistance and low hygroscopicity that do not cause deformation under the conditions of forming a recording layer of an optical disc (usually forming an inorganic thin film such as spattering) and storing conditions.

Plastics are considered to be suitable for optical molded products because they are light-transmissive and easy to mold, and because they are lightweight and are not easily destroyed by external forces such as impact, they are currently described above. It has never been developed to satisfy all the requirements of the above. For example, methacrylic resin, which has a low birefringence phenomenon, has problems in heat resistance and deformation due to moisture absorption, and it has excellent heat resistance such as polycarbonate, and resins with small deformation due to moisture absorption have a large birefringence phenomenon and optical homogeneity to polarized light. There is a drawback. From the background above,
There has been a strong demand for the development of an optical molding material that solves the above three problems.

[Object of the Invention]

An object of the present invention is to solve the above three problems, that is, to provide an optical molded article suitable for an optoelectronic product using a material having a small birefringence, an excellent heat resistance, and a low hygroscopicity. To do. This object can be achieved by the present invention described below.

[Disclosure of Invention]

The present invention is a structural unit represented by the following general formula (A) Having at least a structural unit represented by the following general formula (B) (In the above two formulas, X is a divalent hydrocarbon group having 1 to 8 carbon atoms, O, CO, S, SO or SO ₂ , and R ^{1 to} R ⁸ may be the same or different from each other, and are hydrogen or carbon. (Representing a hydrocarbon group of the number 1 to 5), which is a (co) polymer having two or more structural units (A) and (B) with respect to the total number of moles of the structural unit (A). It is an optical molded article formed by molding a (co) polymer having an occupied mole number of 5% or more.

Regarding the optical molded article of the present invention, The greatest point is that it is formed from a specific polycarbonate resin having the structural unit (A) represented by

In the resin, To produce a compound having the structural unit (A) represented by This can be achieved by using a bisphenol monomer represented by

The above-mentioned monomer can be obtained by various methods, for example, a method obtained by heating isopropenylphenols or a dimer thereof in the presence of an acid catalyst [for example, JP-A-54-76,564.
No. 5,853,651, US Pat. No. 4,334,106, US Pat. No. 3,288,864], a method of directly heating bisphenols in the presence of an acid catalyst [US Pat. No. 2,979,534] by dimerization of α-alkylstyrenes. A method is known in which the indane compound thus obtained is sulfonated and melted with an alkali [US Pat. No. 2,819,249, US Pat. No. 2,754,285].

Specific examples of the monomer include 1,1,3-trimethyl 3- (4'-hydroxyphenyl) 5-indanol,
1,1,3,4,6-pentamethyl 3- (3,5'-dimethyl 4'-hydroxyphenyl) 5-indanol,
1,1,3,4-tetramethyl 3- (3'-methyl 4 '
-Hydroxyphenyl) 5-indanol and the like can be mentioned, and one or more of these are used.

The above-mentioned polycarbonate resin is used as its constituent component. You may have the structural unit (B) represented by. The total number of moles of the structural units (A) and (B) constituting the polycarbonate resin is the number of moles of the structural unit (B) (hereinafter, m
Express with. ) May be in the range of 0 to less than 95. m is
When it is 95 or more, the birefringence is not sufficiently reduced, so that it is unsuitable, and it is particularly preferable that m is 85 or less.

Examples of the raw material that gives the structural unit (B) include 2,
2-bis (4'-hydroxyphenyl) propane, bis (4-hydroxyphenyl) methane, 2,2-bis (3'-methyl 4'-hydroxyphenyl) propane,
1,1-bis (4'-hydroxyphenyl) cyclohexane, bis (4'-hydroxyphenyl) diphenylmethane, 2,2-bis (3 ', 5'-dimethyl4'-hydroxyphenyl) propane, bis ( 3,5-dimethyl 4
-Hydroxyphenyl) methane, bis (4-hydroxyphenyl) ether, bis (4-hydroxyphenyl)
Bisphenols such as sulfide, bis (4-hydroxyphenyl) sulfoxide, bis (4-hydroxyphenyl) sulfone, bis (3,5-dimethyl 4-hydroxyphenyl) sulfone, bis (4-hydroxyphenyl) ketone There are several types, and one or more of these are used.

The polycarbonate resin used in the present invention is preferably a random copolymer in which the structural units (A) and (B) are randomly linked.

The polycarbonate resin used in the present invention is, for example, a method of reacting a mixture of bisphenols described above with phosgene in the presence of pyridine, phosgene or bisgene in a two-phase interface system consisting of an alkaline aqueous solution of a mixture of bisphenols and an organic solvent. It can be produced by a well-known method such as a method of reacting a chloroformate of phenols, a melt polymerization method of a mixture of diphenyl carbonate and bisphenols or a mixture of bisphenols with an acetic acid ester. (For example, H. Schnell “Chemistr
y and Physics of Polycarbonates. ”Interscience P
ublishers, New York-London-Sydney 1964) The polycarbonate resin used in the molded article of the present invention has a logarithmic viscosity η _inh. measured in the following manner in a mixed solvent of phenol / tetrachloroethane (weight ratio 6/4) _. Is 0.1
Those in the range of 2.0 are preferable. When η _inh. is less than 0.1, the mechanical strength of the resin is insufficient and a practical optical molding cannot be obtained. On the other hand, η _inh .
In the area larger than 0, the fluidity during processing becomes poor,
For example, it is difficult to obtain a precise molded product in injection molding and the molded product also has large birefringence, which is not preferable.

The logarithmic viscosity η _inh. Is 35 ° C. in a mixed solvent of phenol / tetrachloroethane (weight ratio 6/4) at a polymer concentration of 0.
A solution of 5 g / dl is used, which is calculated by the following formula.

[In the above formula, t is the flow time of the polymer solution, t ₀ is the flow time of only the solvent, and C is the polymer solution concentration (g / dl). The optical molded article of the present invention using the above-mentioned resin can be obtained by any known molding method such as injection molding, press molding and extrusion molding. In particular, injection molding is preferable for applications such as optical disc substrates with guide grooves and address signals, and plastic lenses with irregular shapes, and injection molding conditions are selected according to the melt viscosity characteristics (eg, melt index) of the resin obtained. However, it is usually molded at a resin temperature of 200 to 400 ° C.

In addition, sheet-shaped optical molded products can be continuously produced by extrusion molding, and transparent electrode substrates for display,
It can be used for optical cards, optical disk cover sheets, etc.

Further, the press molding can be applied to both a deformed product and a sheet, but in terms of productivity, it is inferior to the above two molding methods.

〔The invention's effect〕

The optical molded article of the present invention has extremely small birefringence, is excellent in heat resistance, and has a small warpage due to moisture absorption, and thus is very suitable for various optoelectronic products, in particular, optical disc substrates and transparent electrode substrates for display. is there.

〔Example〕

 Hereinafter, the present invention will be described more specifically with reference to examples.

Production Example 1 In a reactor equipped with a gas introduction pipe and a stirring device, 2,2-
11.41 parts by weight of bis (4'-hydroxyphenyl) propane, 13.42 parts by weight of 1,1,3-trimethyl 3- (4'-hydroxyphenyl) 5-indanol and p-t-
0.75 parts by weight of butylphenol was added together with 150 parts by weight of pure water to stir and suspend, and oxygen was completely removed from the system by passing a N ₂ stream. Then, 18.2 parts by weight of 45% sodium hydroxide solution was added, and the mixture was sufficiently stirred to completely dissolve the powder of the phenols, and cooled to room temperature (25 ° C). Further, add 100 parts by weight of dichloromethane, and continue stirring at room temperature for 1 hour.
1.9 parts by weight of gaseous phosgene was bubbled in at a constant rate for 2 hours. At 15 minutes and 30 minutes after the start of blowing phosgene, 4.0 parts by weight of 45% aqueous sodium hydroxide solution was added. After blowing phosgene, add 0.1 part by weight of triethylamine,
By stirring for 5 minutes, the reaction solution became very viscous, so 20 parts by weight of dichloromethane was added to adjust the viscosity.

After standing, the aqueous layer was separated and removed, the resin solution was washed twice with water, and the obtained resin solution was poured into a homomixer containing methanol to precipitate the resin under high-speed stirring. This was separated and dried to obtain a resin powder. Η _{inh. Of the} obtained powder _.
Is 0.53, and according to the IR and ¹ H-NMR spectra,
The molar ratio between the number of 2,2-bis (4'-hydroxyphenyl) propane residues and the number of 1,1,3-trimethyl-3- (4'-hydroxyphenyl) 5-indanol residues is 50:50.
It was confirmed to be a polycarbonate copolymer of.
^To determine the composition ratio by ¹ H-NMR, δ = 2,2′-bis (4′-hydroxyphenyl) propane residue was used.
1.70 ppm signal (S, CH ₃ groups) and 1,1,3-trimethyl 3- (4'-hydroxyphenyl) 5-indanol residue δ = 1.10 ppm (S, CH ₃ groups), δ = 1.39 ppm
(S, CH ₃ groups), δ = 2.34 ppm (dd, CH ₂ groups), and the integrated intensity measurement value of each signal was used.

Production Examples 2 to 7, 2,2-bis (4'-hydroxyphenyl) propane and 1,1,3-trimethyl 3- in Production Example 1
Table (4'-hydroxyphenyl) 5-indanol-
Example 1 was repeated except that it was used as shown in Example 1 to obtain a colorless resin powder. The η _{inh. Of the} obtained resin is as shown in Table 1, and it was confirmed by IR and ¹ H-NMR spectra that a carbonate polymer having the composition of the bisphenol used as a raw material was obtained. did.

Production Examples 8 to 14 Polymers of η _{inh. Described in} Table-2 were produced in the same manner as in Production Example 1 except that the types and amounts of bisphenols used in Production Example 1 were as shown in Table-2 _. Got

Since only trace amounts of unreacted bisphenol components were detected at the time of production, it is presumed that the bisphenol components (I) and (II) used as raw materials were carbonate polymers in the composition ratio.

Molding and Evaluation of Resin Each resin powder of the above Production Examples 1 to 14 was made into pellets by an extruder with a pelletizer (cylinder temperature 250 ° C.), and each pellet was dried at 110 ° C. for 4 hours and then injection molded. . A stamper with a mirror surface is attached to the mold, and the outer diameter is 120 m.
A disk-shaped molded product having an m and a thickness of 1.2 mm was obtained. The injection molding machine had a cylinder diameter of 30 mm, the injection pressure was 1000 kg, the mold gate was provided in the center of the disk, and the mold temperature was 80 ° C. The cylinder temperature at the time of injection molding was set according to each resin and is shown in Table-3.

The formed disc is punched to have an inner diameter of 15 mm to form a donut-shaped disc, and then aluminum is vacuum-deposited on one side to 600 mm.
Each sample was prepared by providing a reflection layer of angstrom (Sample Nos. 1 to 14), birefringence, sled under humidity environment,
The heat resistance was evaluated.

Sample numbers 1 to 6 and 8 to 14 are examples of the present invention, and sample number 7 is a comparative example.

For birefringence, a double-pass optical path difference was obtained using a reflective polarization microscope. For the sled in the humidity environment,
The sample was left to stand in a constant temperature and humidity chamber at 95 ° C% relative humidity for 24 hours, and immediately after taking out, it was left in a constant temperature and constant humidity chamber at 20 ° C and 60% relative humidity for 2 hours, and the displacement due to the sled was measured. For heat resistance, the deflection temperature under load was measured according to ASTM-D648. The above evaluation results are also shown in Table 3.

As a comparative example, methacrylic resin (trade name Acrypet VH manufactured by Mitsubishi Rayon Co., Ltd.) was injection molded in the same manner as above except that the mold temperature was set to 65 ° C., and an aluminum reflective layer was provided in the same manner for testing. Create a sample (Sample No. 15)
The evaluation was performed, and the results are also shown in Table-3.

From the results of the above Examples and Comparative Examples, it is apparent that the optical component of the present invention has a smaller birefringence than that of the conventional one, is excellent in heat resistance, and has a small warpage due to moisture absorption.

Claims (3)

[Claims] 1. A structural unit represented by the following general formula (A): Having at least a structural unit represented by the following general formula (B) (In the above two formulas, X is a divalent hydrocarbon group having 1 to 8 carbon atoms, O, CO, S, SO or SO ₂ , and R ^{1 to} R ⁸ may be the same or different from each other, and are hydrogen or carbon. (Representing a hydrocarbon group of the number 1 to 5), which is a (co) polymer having two or more structural units (A) and (B) with respect to the total number of moles of the structural unit (A). An optical molded product obtained by molding a (co) polymer having a molar number of 5% or more. 2. The optical molded product according to claim 1, wherein the optical molded product is an optical disk substrate. 3. The optical molded product according to claim 1, wherein the optical molded product is a transparent electrode substrate for a display.