JPH10109950A - Optical part - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an optical part useful for optical recording medium substrate, optical lens, etc., excellent in transparency, mechanical strength and heat resistance and low in double refraction, by using an aromatic polycarbonate containing a specific structural unit. SOLUTION: For this optical part, (A) an aromatic polycarbonate containing >=5mol%, preferably >=20mol% of a structural unit derived from (A1 ) a compound of the formula (R is methyl or phenyl), is used. The component A is obtained, for example, by reacting the component A1 and optionally the component A1 and another aromatic dihydroxy compound [e.g. a bis(hydroxyaryl) alkane] with a polycarbonate precursor such as a halogenated carbonyl compound, a haloformate compound or a carboxylic acid diester.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to an optical component. The optical component of the present invention has good transparency, mechanical strength, and heat resistance, and has low birefringence, and is useful as an optical disc substrate, a pickup lens, a plastic substrate for a liquid crystal cell, a prism, and the like. .

[0002]

2. Description of the Related Art Inorganic glass is used in a wide range of fields as a transparent material because of its excellent properties such as excellent transparency and small optical anisotropy. However,
There are problems such as being heavy and easy to break, poor productivity, and the like, and in recent years, transparent polymers have been actively developed in place of inorganic glass. As transparent polymers, for example, polymethyl methacrylate, polycarbonate, and the like are excellent in transparency and mechanical properties (for example, impact resistance, etc.), and are excellent in processability and moldability. For example, they are used for transparent parts and lenses of automobiles.

[0003] On the other hand, sound, images,
The use of optical disks for recording and reproducing information such as characters has been rapidly expanding in recent years. However, in an optical disc used as an information recording medium, not only is it transparent because a laser beam passes through the disc body, but also optical homogeneity is strongly required to reduce an error in reading information. . That is, for example, when a conventionally known polymer (for example, polycarbonate, polymethyl methacrylate, or the like) is used, thermal stress, molecular orientation, and the vicinity of the glass transition point generated in the process of cooling and flowing the resin at the time of molding the disk substrate. The birefringence occurs when the laser beam passes through the disk substrate due to residual stress caused by a change in volume of the laser beam. The large optical non-uniformity caused by the birefringence is a fatal defect for an optical component such as an optical disc substrate, for example, an error in reading recorded information occurs. In optical components such as the optical disk substrate, a material having higher optical characteristics, that is, a material having low birefringence and excellent transparency and heat resistance is required.

One of the methods for solving the above-mentioned problems is a low-birefringence polycarbonate using a spiro compound, such as a spirobiindanol alone or a copolymerization type polycarbonate of spirobiindanol and bisphenol A. (JP-A-63-31423)
No. 5). However, although the former polycarbonate has low birefringence, transparency and mechanical strength are poor,
Practically has a problem, and the latter polycarbonate increases transparency and mechanical strength by increasing the bisphenol A component, but increases the birefringence,
There is a problem that the range of use as an optical component is limited, and it has been strongly desired to solve these conflicting problems.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide an optical component which overcomes the above-mentioned problems and has good transparency, mechanical strength and heat resistance and low birefringence. It is.

[0006]

Means for Solving the Problems The present inventors have made intensive studies on the above problems, and as a result, have reached the present invention. That is, the present invention relates to an optical component made of an aromatic polycarbonate containing a structural unit derived from an aromatic dihydroxy compound represented by the general formula (1) (formula 2).

[0007]

Embedded image (Wherein, R represents a methyl group or a phenyl group)

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. The aromatic polycarbonate according to the present invention is an aromatic polycarbonate containing a structural unit derived from an aromatic dihydroxy compound represented by the general formula (1). )
And a copolymerized polycarbonate containing a structural unit derived from an aromatic dihydroxy compound represented by the formula:
The structural unit derived from the aromatic dihydroxy compound represented by the general formula (1) according to the present invention is represented by the general formula (1-
a) It is a structural unit represented by (Chemical Formula 3).

[0009]

Embedded image (Wherein, R represents a methyl group or a phenyl group)

The structural unit represented by the general formula (1-a) is
Bonds with the carbonyl group represented by the formula (2) to form an aromatic polycarbonate. — (C ＝ O) — (2) In the aromatic dihydroxy compound represented by the general formula (1) according to the present invention, R represents a methyl group or a phenyl group, and preferably represents a methyl group. The aromatic dihydroxy compound represented by the general formula (1) is suitably produced by a known method, for example, by reacting a phenol derivative with an acetophenone derivative in the presence of an acidic catalyst.

The aromatic polycarbonate according to the present invention comprises:
An aromatic polycarbonate containing a structural unit derived from the aromatic dihydroxy compound represented by the general formula (1) may be a homopolycarbonate or a copolymerized polycarbonate. When the aromatic polycarbonate of the present invention is a copolymerized polycarbonate,
It may be a copolymerized polycarbonate containing a structural unit containing a plurality of structural units represented by the general formula (1-a), and a structural unit represented by the general formula (1-a) It may be a copolymerized polycarbonate containing structural units containing structural units other than the above. The general formula (1-
When a structural unit other than the structural unit represented by a) is contained, the proportion occupied by the structural unit represented by the general formula (1-a) in all the structural units is not particularly limited.
It is at least 10 mol%, preferably at least 10 mol%, more preferably at least 20 mol%.

The aromatic polycarbonate according to the present invention comprises:
It may contain a structural unit derived from an aromatic dihydroxy compound other than the aromatic dihydroxy compound represented by the general formula (1). Specific examples of the aromatic dihydroxy compound include bis (4-hydroxyphenyl) methane,
1-bis (4'-hydroxyphenyl) ethane, 1,2-bis (4'-hydroxyphenyl) ethane, bis (4-hydroxyphenyl) phenylmethane, bis (4-hydroxyphenyl) diphenylmethane, bis (4-hydroxy Phenyl) -1-naphthylmethane, 1,1-bis (4′-hydroxyphenyl) -1-phenylethane, 2,2-bis (4′-hydroxyphenyl) propane [“bisphenol A”], 2- (4 '-
Hydroxyphenyl) -2- (3′-hydroxyphenyl) propane, 2,2-bis (4′-hydroxyphenyl) butane,
1,1-bis (4'-hydroxyphenyl) butane, 2,2-bis (4'-hydroxyphenyl) -3-methylbutane, 2,2-bis (4'-hydroxyphenyl) pentane, 3,3-bis (4'-hydroxyphenyl) pentane, 2,2-bis (4'-hydroxyphenyl) hexane, 2,2-bis (4'-hydroxyphenyl) octane, 2,2-bis (4'-hydroxyphenyl)- 4-methylpentane, 2,2-bis (4'-hydroxyphenyl) heptane, 4,4-bis (4'-hydroxyphenyl) heptane, 2,
2-bis (4'-hydroxyphenyl) tridecane, 2,2-bis (4'-hydroxyphenyl) octane, 2,2-bis (3'-
Methyl-4'-hydroxyphenyl) propane, 2,2-bis (3'-ethyl-4'-hydroxyphenyl) propane,
2-bis (3'-n-propyl-4'-hydroxyphenyl)
Propane, 2,2-bis (3'-isopropyl-4'-hydroxyphenyl) propane, 2,2-bis (3'-sec-butyl-4'-hydroxyphenyl) propane, 2,2-bis (3 ' −
tert-butyl-4′-hydroxyphenyl) propane, 2,2-bis (3′-cyclohexyl-4′-hydroxyphenyl) propane, 2,2-bis (3′-allyl-4′-hydroxyphenyl) propane, 2,2-bis (3'-methoxy-4 '
-Hydroxyphenyl) propane, 2,2-bis (3 ', 5'-dimethyl-4'-hydroxyphenyl) propane, 2,2-bis (2', 3 ', 5', 6'-tetramethyl-4 '-Hydroxyphenyl) propane, bis (4-hydroxyphenyl) cyanomethane, 1-cyano-3,3-bis (4'-hydroxyphenyl) butane, 2,2-bis (4'-hydroxyphenyl) hexafluoropropane, etc. Bis (hydroxyaryl) alkanes of

1,1-bis (4'-hydroxyphenyl) cyclopentane, 1,1-bis (4'-hydroxyphenyl) cyclohexane, 1,1-bis (4'-hydroxyphenyl) cycloheptane, 1,1 -Bis (3'-methyl-4'-hydroxyphenyl) cyclohexane, 1,1-bis (3 ', 5'-dimethyl-
4'-hydroxyphenyl) cyclohexane, 1,1-bis (3 ', 5'-dichloro-4'-hydroxyphenyl) cyclohexane, 1,1-bis (3'-methyl-4'-hydroxyphenyl) -4- Methylcyclohexane, 1,1-bis (4'-hydroxyphenyl) -3,3,5-trimethylcyclohexane, 2,
2-bis (4'-hydroxyphenyl) norbornane, 2,2-
Bis (hydroxyaryl) cycloalkanes such as bis (4'-hydroxyphenyl) adamantane, 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxy-3,
Bis (hydroxyaryl) ethers such as 3'-dimethyldiphenylether and ethylene glycol bis (4-hydroxyphenyl) ether, 4,4'-dihydroxydiphenylsulfide, 3,3'-dimethyl-4,4'-dihydroxydiphenylsulfide , 3,3'-Dicyclohexyl-
Bis (hydroxyaryl) sulfides such as 4,4'-dihydroxydiphenylsulfide, 3,3'-diphenyl-4,4'-dihydroxydiphenylsulfide, 4,4'-dihydroxydiphenylsulfoxide, 3,3'-dimethyl- Four,
Bis (hydroxyaryl) sulfoxides such as 4′-dihydroxydiphenylsulfoxide, bis (hydroxyaryl) sulfones such as 4,4′-dihydroxydiphenylsulfone, 4,4′-dihydroxy-3,3′-dimethyldiphenylsulfone, Bis (hydroxyaryl) ketones such as bis (4-hydroxyphenyl) ketone and bis (4-hydroxy-3-methylphenyl) ketone;

Further, 6,6'-dihydroxy-3,3,3 ', 3'
-Tetramethylspiro (bis) indane ["spirobiindanebisphenol"], 7,7'-dihydroxy-3,
3 ', 4,4'-tetrahydro-4,4,4', 4'-tetramethyl-2,2'-
Spirobi (2H-1-benzopyran), trans-2,3-
Bis (4'-hydroxyphenyl) -2-butene, 9,9-bis (4'-hydroxyphenyl) fluorene, 3,3-bis (4 '
-Hydroxyphenyl) -2-butanone, 1,6-bis (4'-
Hydroxyphenyl) -1,6-hexanedione, α, α,
α ', α'-tetramethyl-α, α'-bis (4-hydroxyphenyl) -p-xylene, α, α, α', α'-
Tetramethyl-α, α′-bis (4-hydroxyphenyl) -m-xylene, 4,4′-dihydroxybiphenyl, hydroquinone, resorcin and the like. Further, an aromatic dihydroxy compound containing an ester bond which can be produced, for example, by reacting 2 mol of bisphenol A with 1 mol of isophthaloyl chloride or terephthaloyl chloride is also useful. These may be used alone or in combination of two or more.

In the present invention, bis (hydroxyaryl) alkanes or bis (hydroxyaryl) cycloalkanes are preferred, and bis (hydroxyaryl) alkanes are more preferred, of which 2,2-bis (4'-hydroxy Phenyl) propane (bisphenol A) is more preferred. Furthermore, the aromatic polycarbonate according to the present invention is derived from the aromatic dihydroxy compound represented by the general formula (1) and other aromatic dihydroxy compounds other than the general formula (1) as long as the desired effect is not impaired. And a structural unit other than the carbonyl group represented by the formula (2).

Examples of such a structural unit include a structural unit derived from a bifunctional compound other than the above-mentioned aromatic dihydroxy compound, and a terminal group. Examples of the bifunctional compound include compounds such as an aliphatic dihydroxy compound, an aromatic dicarboxylic acid, an aliphatic dicarboxylic acid, an aromatic diamine, an aliphatic diamine, an aromatic diisocyanate, and an aliphatic diisocyanate. Examples of the structural unit other than the carbonyl group represented by the formula (2) include groups such as an imino group, an ester group, an ether group, an imide group, and an amide group.

In the aromatic polycarbonate used in the present invention, the terminal group is a hydroxy group, a haloformate group,
It may be a reactive terminal group such as a carbonate group, or may be an inert terminal group sealed with a molecular weight regulator. Here, as the molecular weight regulator, a monovalent hydroxy aromatic compound, an alkali metal or alkaline earth metal salt of a monovalent hydroxy aromatic compound, a haloformate compound of a monovalent hydroxy aromatic compound, a monovalent hydroxy aromatic compound Compound carbonate, monovalent carboxylic acid, 1
And alkali metal or alkaline earth metal salts of monovalent carboxylic acids, acid halides of monovalent carboxylic acids, esters of monovalent carboxylic acids, and the like.

Specific examples of the molecular weight regulator include the following compounds. Examples of the monovalent hydroxy aromatic compound include phenol, 4-tert-butylphenol, 2-cresol, 3-cresol, 4-cresol, 2-ethylphenol, 4-ethylphenol, 4-cumylphenol, and 4-phenylphenol ,
4-cyclohexylphenol, 4-n-octylphenol, 4-isooctylphenol, 4-nonylphenol, 4-methoxyphenol, 4-n-hexyloxyphenol, 4-isopropenylphenol, 2-
Chlorophenol, 3-chlorophenol, 4-chlorophenol, 2-bromophenol, 3-bromophenol, 4-bromophenol, 2,4-dichlorophenol, 2,4-dibromophenol, pentachlorophenol, pentabromophenol, β-naphthol, α
-Naphthol, 2- (4'-methoxyphenyl) -2-
(4 "-hydroxyphenyl) propane, etc. Examples of the alkali metal or alkaline earth metal salt of the monovalent hydroxyaromatic compound include sodium, potassium and calcium salts of the above-mentioned monovalent hydroxyaromatic compound. Examples of the haloformate derivative of the monovalent hydroxyaromatic compound include the above-mentioned monovalent hydroxyaromatic compounds such as chloroformate and bromoformate.

The monovalent carboxylic acids include acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, heptanoic acid, caprylic acid, 2,2-dimethylpropionic acid, 3-methylbutyric acid, 3,3-dimethylbutyric acid, 4-methylvaleric acid, 3,3
Aliphatic carboxylic acids such as dimethylvaleric acid, 4-methylcaproic acid, 2,4-dimethylvaleric acid, 3,5-dimethylcaproic acid, and phenoxyacetic acid; benzoic acid; 4-propoxybenzoic acid; 4-butoxybenzoic acid And benzoic acids such as 4-pentyloxybenzoic acid, 4-hexyloxybenzoic acid, and 4-octyloxybenzoic acid. Examples of the alkali metal or alkaline earth metal salt of a monovalent carboxylic acid include the sodium, potassium, and calcium salts of the above-described monovalent carboxylic acid. Examples of the acid halide derivative of a monovalent carboxylic acid include chlorides and bromides of the above-mentioned monovalent carboxylic acid.

The aromatic polycarbonate used in the present invention is obtained by reacting an aromatic dihydroxy compound represented by the general formula (1) with a carbonate precursor, and if desired, an aromatic dihydroxy compound represented by the general formula (1). The compound is produced by reacting a compound with another aromatic dihydroxy compound in combination with a carbonate precursor. A carbonate precursor is a compound that reacts with a hydroxy group of an aromatic dihydroxy compound to generate a carbonate bond, and examples thereof include a carbonyl halide compound, a haloformate compound, and a carbonic acid diester.

The production method is classified into the following methods according to the type of the compound used as the carbonate precursor. That is, (1) a method using a carbonyl halide compound or a haloformate compound as an aromatic dihydroxy compound and a carbonate precursor, and (2) a method using a carbonic acid diester as an aromatic dihydroxy compound and a carbonate precursor. The carbonyl halide compound includes carbonyl chloride (phosgene), carbonyl bromide, carbonyl iodide and mixtures thereof, trichloromethylchloroformate which is a dimer of carbonyl chloride, and bis (trichloromethane which is a trimer of carbonyl chloride. Methyl) carbonate and the like. Preferably, it is carbonyl chloride. The haloformate compound is a bis or monohaloformate compound, an oligomeric bis or monohaloformate compound, or a mixture thereof.

The above-mentioned production method (1) is a production method usually called a solution polymerization method or an interfacial polymerization method. The solution polymerization method is a method in which an aromatic dihydroxy compound and a carbonyl halide compound (for example, carbonyl chloride) are reacted in an organic solvent in the presence of an organic base such as pyridine. In the interfacial polymerization method, a reaction between an aromatic dihydroxy compound and an aqueous solution comprising an alkali metal or alkaline earth metal base and an organic solvent is carried out under an interface condition comprising an organic solvent, and a catalyst (for example, triethylamine This is a production method in which a polycondensation reaction is carried out in the presence of) In addition, the production method (2) is a method usually called a transesterification method, in which an aromatic dihydroxy compound and a carbonic acid diester (for example, diphenyl carbonate) are heated in a molten state or a solution state, if necessary, under the presence of a catalyst. It is a method of reacting below. The method for producing the aromatic polycarbonate according to the present invention is not particularly limited, and is produced by various known methods described above, for example, a known method selected from a transesterification method, an interfacial polymerization method, and a solution polymerization method. It is possible. Preferably, it is produced by the production method (1), and more preferably, by the interfacial polymerization method in the production method (1).

When the aromatic polycarbonate according to the present invention is produced as a copolymerized polycarbonate, the structure of the copolymerized polycarbonate may be alternating copolymerization, random copolymerization or block copolymerization. Is also good. The molecular weight of the aromatic polycarbonate according to the present invention is not particularly limited.
The weight average molecular weight as a standard polystyrene equivalent molecular weight measured by (gel permeation chromatography) is 5,000 to 100,000, preferably
10,000 to 90000, more preferably 15
000 to 80,000. The polydispersity index represented as a ratio between the weight average molecular weight and the number average molecular weight is not particularly limited, but is preferably
1.5 to 6.0, more preferably 2.0 to 5.0.
0, and more preferably 2.0 to 4.5.

The optical components made of the polycarbonate of the present invention include optical recording medium substrates such as optical disk substrates and magneto-optical disk substrates, optical lenses such as pickup lenses, and the like.
Various optical components such as a plastic substrate for a liquid crystal cell and a prism can be used. Polycarbonate according to the present invention is thermoplastic, injection molding in a molten state, extrusion molding,
Blow molding, impregnation with a filler or the like can be performed, and further, molding can be easily performed by various known molding methods such as compression molding and solution casting. The optical component of the present invention can be suitably manufactured by these known various molding methods (typically, injection molding and the like). When the optical component of the present invention is manufactured, the aromatic component according to the present invention is used. In addition to polycarbonate, it is also possible to use it as an optical component by blending it with an aromatic polycarbonate derived from 2,2-bis (4'-hydroxyphenyl) propane as long as the desired effect is not impaired. Further, it is also possible to manufacture an optical component in combination with another polymer. As such other polymers, polyethylene, polypropylene, polystyrene, ABS resin, polymethyl methacrylate, polytrifluoroethylene, polytetrafluoroethylene, polyacetal, polyphenylene oxide, polybutylene terephthalate, polyethylene terephthalate, polyamide, polyimide, polyamide imide, Examples thereof include polyetherimide, polysulfone, polyethersulfone, paraoxybenzoyl-based polyester, polyarylate, and polysulfide.

When manufacturing the optical component of the present invention,
For the polycarbonate according to the present invention, a pigment, a dye,
Heat stabilizers, antioxidants, ultraviolet absorbers, release agents, organic halogen compounds, alkali metal sulfonates, glass fibers, carbon fibers, glass beads, barium sulfate, TiO ₂
And other known additives. The optical component of the present invention thus obtained has excellent transparency, heat resistance, etc., and has low birefringence, and is very useful.

[0026]

EXAMPLES Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited to the following examples. In addition, the measurement of the molecular weight of the aromatic polycarbonate produced in each Production Example or Comparative Example was performed by the following method. Molecular weight: A 0.2% by weight solution of an aromatic polycarbonate in chloroform was subjected to GPC (gel permeation chromatography) [System manufactured by Showa Denko KK,
-11] to determine the weight average molecular weight (Mw). The measured value is a value in standard polystyrene conversion.

Production Example 1 A stirrer equipped with a lattice blade, a reflux condenser, and a dip tube for blowing phosgene were provided in a baffled flask having a content of 2 liters. In this flask, 145 g (0.50 mol)
Of 1,1-bis (4-hydroxyphenyl) -1-phenylethane, 56 g (1.40 mol) of sodium hydroxide, 2.58 g of 4-tert-butylphenol, and 600 ml of deionized water. To prepare an aqueous solution. Thereafter, 600 ml of dichloromethane was added to the aqueous solution to form a two-phase mixture. While stirring the two-phase mixture, 59.4 g (0.60 mol) of carbonyl chloride was supplied to the mixture at 9.9 g / min. Feeded at speed. After the supply of carbonyl chloride was completed, 0.08 g of triethylamine was added to the reaction mixture, and the mixture was further stirred and mixed for 90 minutes. Stirring was then stopped, the reaction mixture was separated, the dichloromethane phase was neutralized with aqueous hydrochloric acid and washed with deionized water until substantially no electrolyte was detected in the aqueous washing solution. Thereafter, dichloromethane was evaporated from the dichloromethane phase by evaporation to obtain an aromatic polycarbonate having a structure represented by the following formula (1-1) (formula 4) in a solid state. Weight average molecular weight is 5
It was 1,000.

[0028]

Embedded image

Production Example 2 Production Example 1 was repeated except that bis (4-hydroxyphenyl) -diphenylmethane was used instead of 1,1-bis (4-hydroxyphenyl) -1-phenylethane. By a method similar to the method described, a polycarbonate represented by the following formula (1-2) (Formula 5) was obtained in a solid state. The weight average molecular weight was 55,000.

[0030]

Embedded image

Production Example 3 A known polycarbonate was produced from bisphenol A and phosgene according to a conventional method (interfacial polymerization method). Contents 20
A 1 liter baffled flask was equipped with a stirrer equipped with a lattice blade, a reflux condenser, and a dip tube for blowing phosgene. In this flask, 1140 g (5.0 mol) of 2,2-
Bis (4'-hydroxyphenyl) propane, 560 g
(14.0 mol) sodium hydroxide, 25.8 g of 4
An aqueous solution was prepared by charging tert-butylphenol and 6 liters of deionized water. Thereafter, 6 liters of dichloromethane was added to the aqueous solution to form a two-phase mixture, and while stirring the two-phase mixture, 594 was added to the mixture.
g (6.0 mol) of carbonyl chloride was fed at a feed rate of 9.9 g / min. After the end of the supply of carbonyl chloride, 0.1.
81 g of triethylamine was added to the reaction mixture and stirred for another 90 minutes. Stirring was then stopped, the reaction mixture was separated, the dichloromethane phase was neutralized with aqueous hydrochloric acid and washed with deionized water until substantially no electrolyte was detected in the aqueous washing solution. Thereafter, dichloromethane was evaporated and distilled off from the dichloromethane phase to obtain a known bisphenol A / polycarbonate as a colorless solid. The weight average molecular weight was 50,000.

Production Example 4 A copolymer polycarbonate of bisphenol A and spirobiindanol was produced according to the method described in Example 7 of JP-A-63-314235. The weight average molecular weight was 44,800.

Examples 1 and 2 Each of the polycarbonates produced in Production Examples 1 and 2 was press-molded to produce a 1.2 mm-thick plate-like test piece. This test piece was subjected to an evaluation test according to the following method. The results are shown in Table 1 (Table 1). Comparative Examples 1 and 2 Test pieces were prepared in the same manner as in Examples 1 and 2 using each of the polycarbonates produced in Production Examples 3 and 4, and evaluated in the same manner. The results are shown in Table 1.

[Evaluation Methods] (1) Appearance: The transparency and optical surface condition of the test piece were visually observed and evaluated. ：: Colorless and transparent, good surface condition without cracks, cracks, surface roughness, etc. ×: Those with observed cracks, cracks, surface roughness, etc. (2) Total light transmittance (hereinafter referred to as transmittance): AST
The MD-1003 method was followed. (3) Birefringence: measured by an ellipsometer. (4) Heat resistance: After leaving in a hot-air drying group at 120 ° C. for 4 hours, a test piece was taken out, visually observed and evaluated. ：: No coloring, surface distortion, crack, etc. of the molded product ×: Coloring, surface distortion, crack, etc. of the molded product observed

[0035]

[Table 1] As is clear from Table 1, a molded product obtained by molding a polycarbonate containing a structural unit derived from an aromatic dihydroxy compound represented by the general formula (1) has good transparency, heat resistance, and the like. And has low birefringence.

Example 3 (Preparation and evaluation of optical disk) The polycarbonate produced in Production Example 1 was formed into pellets using an extruder with a pelletizer (cylinder temperature 250 ° C.). After drying the pellets at 110 ° C. for 4 hours,
Injection molding was performed at 280 ° C. That is, a stamper having a mirror surface was mounted on a mold to obtain a disk-shaped molded product having an outer diameter of 130 mm and a thickness of 1.2 mm. A central portion of the obtained molded product (base) was punched out so as to have an inner diameter of 15 mm to form a donut-shaped disk. Then, aluminum was vacuum-deposited on one side to provide a reflective layer having a thickness of 600 Å. The birefringence and BER (bit error rate) of the obtained optical disk were measured. The bit error rate was measured by using a laser beam having a wavelength of 780 nm, a linear velocity of 2 m / sec, and 0.8 mW, and the rate of occurrence of recording reading errors was measured. The results are shown in Table 2 (Table 2).

Example 4 Except for using the polycarbonate produced in Production Example 2,
An optical disk was manufactured and evaluated by a method similar to the method described in Example 3. The results are shown in Table 2.

Comparative Example 3 An optical disk was produced in the same manner as in Example 3 except that the polycarbonate produced in Production Example 3 was used. The results of measuring the birefringence and BER (bit error rate) of the obtained optical disk are shown in Table 2 below.

Comparative Example 4 An optical disk was produced in the same manner as in Example 3 except that the polycarbonate produced in Production Example 4 was used. The results of measuring the birefringence and BER (bit error rate) of the obtained optical disk are shown in Table 2 below.

[0040]

[Table 2] As is clear from Table 2, the optical disk of the present invention has an improved BER due to a decrease in birefringence as compared with an optical disk obtained by using existing polycarbonate.

Example 5 (Production of magneto-optical disk and evaluation of recording characteristics) The polycarbonate obtained in Production Example 1 was formed into pellets using an extruder with a pelletizer (cylinder temperature: 250 ° C). After drying the pellets at 110 ° C. for 4 hours,
Injection molding was performed. That is, a stamper having a mirror surface was mounted on a mold to obtain a disk-shaped molded product having an outer diameter of 130 mm and a thickness of 1.2 mm. On the obtained molded product (base),
Using an alloy target of Tb 23.5, Fe 64.2, Co 12.3 (atomic%), in a sputtering apparatus (RF sputtering apparatus, manufactured by Nihon Vacuum Co., Ltd.), a thickness of 1000
An Angstrom magneto-optical recording layer was formed. On this recording film, a protective film of inorganic glass having a thickness of 1000 Å was formed using the same sputtering apparatus as described above. Birefringence, CN ratio, BE of the obtained magneto-optical disk
R (bit error rate) and CN retention rate were measured. The CN ratio is as follows: write power 7 mW, read power 1 mW, carrier frequency 1 MHz, resolution bandwidth 3
The measurement was performed at 0 KHz. The CN retention was determined by measuring the CN after 30 days at 60 ° C. and 90% RH with respect to the initial CN ratio.
The degree of decrease in the ratio was shown as a percentage (%). The results are shown in Table 3 (Table 3).

Example 6 A magneto-optical disk was produced in the same manner as in Example 4 except that the polycarbonate produced in Production Example 2 was used. Birefringence of the obtained magneto-optical disk, CN
Table 3 shows the measurement results of the ratio, BER (bit error rate), and CN change rate.

Comparative Example 5 A magneto-optical disk was produced in the same manner as in Example 5 except that the polycarbonate produced in Production Example 3 was used. Birefringence of the obtained magneto-optical disk, CN
Table 3 shows the measurement results of the ratio, BER (bit error rate) and CN retention.

Comparative Example 6 A magneto-optical disk was produced in the same manner as in Example 5 except that the polycarbonate produced in Production Example 4 was used. Birefringence of the obtained magneto-optical disk, CN
Table 3 shows the measurement results of the ratio, BER (bit error rate) and CN retention.

[0045]

[Table 3] As is evident from Table 3, the magneto-optical disk of the present invention has a lower CN ratio and BER compared to a magneto-optical disk obtained from existing polycarbonate due to a decrease in birefringence.
And the CN retention is improved.

[0046]

According to the present invention, it is possible to provide an optical component having excellent transparency, heat resistance, etc., and low birefringence, which is very useful for applications such as an optical disk substrate and a pickup lens. became. In particular, an optical disc substrate obtained by using a polycarbonate containing a structural unit derived from the aromatic dihydroxy compound represented by the general formula (1) of the present invention has excellent optical recording characteristics and
It has excellent durability (heat resistance, moisture resistance, etc.).

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Keisuke Takuma 1190 Kasama-cho, Sakae-ku, Yokohama-shi, Kanagawa Prefecture Inside Mitsui Toatsu Chemical Co., Ltd. (72) Inventor Akihiro Yamaguchi 1190 Kasama-cho, Sakae-ku, Yokohama-shi, Kanagawa Mitsui Toatsu Chemical Inside the corporation

Claims (2)

[Claims] 1. An optical component comprising an aromatic polycarbonate containing a structural unit derived from an aromatic dihydroxy compound represented by the general formula (1) (Formula 1). Embedded image (Wherein, R represents a methyl group or a phenyl group) 2. The aromatic polycarbonate according to claim 1, wherein the structural unit derived from the aromatic dihydroxy compound represented by the general formula (1) is contained in an amount of 5 to 95 mol% based on all structural units. Item 1. The optical component according to Item 1.