JP2003137998A - Optical disk - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a base plate that can reduce electric charge when the discs are produced by injecting a aromatic polycarbonate and they are transported and has a small optical birefringence and to provide a direct read after write optical disk by using the base material. SOLUTION: A base plate for optical disks is produced by injecting an aromatic polycarbonate resin that is produced by transesterification reaction between an aromatic hydroxy compound and a carbonic diester and has a terminal structure represented by general formula (1) (wherein R<1> -R<5> are each independently H, F or a 1-20C perfluoroalkyl group except the case where all of the R<1> -R<5> are H) in an amount of 0.1-99 mol.% based on the total terminal structures and has a viscosity-average molecular weight of 10,000-23,000 carbonic diester. The draw type optical disks are produced by forming at least organic color recording layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disc which is a high density storage medium. In particular, the present invention relates to a write-once optical disc using an organic dye in the optical recording layer.

[0002]

2. Description of the Related Art An optical disk has been rapidly increasing in production in recent years as an information recording medium of low cost and high density recording capacity. In particular, a CD (compact disc), a DVD (digital versatile disc), or an optical disc called a CD-R (write-once compact disc) or a DVD-R (write-once digital versatile disc) having a function capable of additionally recording to these. Has a high capacity and its price is decreasing with the rapid spread. Therefore, the improvement of the signal characteristics and the productivity of the substrate are emphasized, and further high density is expected in the future.

CD which adopts an optical recording method using a laser
With DVDs and DVDs, data can usually be recorded only once,
Digital information is stored in the form of high optical density marks or pits against a reflective background and read by focused laser light. Further, a CD-R or a DVD-R usually has a recording layer made of a dye layer, and data can be additionally written only once.

In general, the material used for the optical disk substrate is a transparent thermoplastic amorphous resin such as polycarbonate, polymethylmethacrylate, amorphous polyolefin, etc., but it has strength, heat resistance, dimensional stability, low cost, etc. From the surface,
Polycarbonate is commonly used. In particular, a polycarbonate produced from an aromatic dihydroxy compound and a carbonic acid diester by an ester exchange method does not use toxic phosgene gas or an organic solvent, as compared with a polycarbonate produced by an interfacial method which has been widely used in the past. Therefore, the environmental load is small, and the manufacturing process is simplified as compared with the interfacial method, so that there is a great advantage that a product of stable quality can be obtained. Furthermore, it has the advantage of being able to convert the by-product generated by the transesterification reaction into the raw material monomer, and is suitable for resin for optical disk substrates because of its advantages such as environmental friendliness, stable quality, and low cost.

A disadvantage of the aromatic polycarbonate is that it has a poor meltability during injection molding due to its high melt viscosity. Therefore, the transferability of the signal is poor, and the birefringence due to the strain inside the substrate becomes large, which causes an error in the signal reproduction. By lowering the viscosity average molecular weight of polycarbonate, the melt viscosity at the time of molding is lowered, and by improving the fluidity, high density signals can be transferred to the substrate,
It is possible to reduce the birefringence generated by the strain inside the substrate. However, the viscosity average molecular weight of the optical polycarbonate currently used for the transparent substrate is 1
It is about 5,000, and if the molecular weight is further reduced, another problem such as reduction in strength of the substrate occurs. On the other hand, if the molecular weight is too high, the strength and heat resistance are improved, but the melt viscosity at the time of molding becomes high, which causes a decrease in transferability and an increase in birefringence. Therefore, it is necessary to develop an aromatic polycarbonate having an appropriate molecular weight and further reduced birefringence.

It is known that the injection-molded optical disk substrate manufactured by the transesterification method has a property of being easily charged to a negative polarity, as compared with the polycarbonate manufactured by the interfacial method (JP-A-11-279396). ). It is stated in this patent that if the surface of the optical disk substrate is negatively charged, dust in the air is likely to adhere and the wettability of the dye of the write-once type optical disk is deteriorated. Ideas for adding agents have been proposed. However, the use of an antistatic agent is not preferable because the addition of the antistatic agent to the polycarbonate causes a drawback that transparency is deteriorated and that it is easily decomposed when exposed to high temperature and high humidity for a long time. US Patent 6,
No. 022,943 is disclosed in US Pat. No. 6,140,4 by reducing the hydroxyl end of the polycarbonate.
No. 57 proposes a method of reducing charging by modifying the molecular end of a polycarbonate resin with a specific alkylphenol group. According to the method of these U.S. Patents, although it is effective in reducing the peeling charge from the stamper generated during the molding of the substrate, the charge generated by the friction with the air further generated during the transportation of the molded substrate is suppressed. No effect is seen.

In Japanese Unexamined Patent Publication (Kokai) No. 5-9283, the ends of an aromatic polycarbonate obtained by a transesterification method are sealed with an aliphatic hydrocarbon group and an aromatic hydrocarbon group,
A method for improving fluidity during melt molding has been proposed. According to the publication of the same patent, the aromatic hydrocarbon group used for end capping may be halogen-substituted, and specific examples thereof include bromo-containing aromatic groups such as bromocoumarone derivatives. No example is shown in which the end of the aromatic polycarbonate obtained by the transesterification method is capped with a bromo-containing aromatic group. Further, in the publication, as an effect of sealing the end, it is stated that improvement of fluidity prevents deterioration of transparency and hue while maintaining mechanical properties, but Nothing is said about the charge on injection molded substrates. Therefore, a method for sufficiently reducing the electrostatic charge of a molded substrate using the transesterification method polycarbonate has not been found to date. In particular,
When a CD-R or a DVD-R is manufactured, it is difficult to form a uniform dye recording layer on the substrate if the molded substrate is highly charged, so that it is possible to reduce the substrate charging.
Moreover, there is a demand for a technique for obtaining a substrate with few defects such as birefringence.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to provide an optical disc and a write-once optical disc having a small birefringence by reducing the charge of a substrate injection-molded by using an aromatic polycarbonate obtained by a transesterification method. To do.

[0009]

In order to solve the above-mentioned object, the inventors of the present invention have made earnest studies and, as a result, have found that the charging phenomenon of aromatic polycarbonate obtained by the transesterification method on an optical disk molding substrate is caused by the molecular terminal of the polycarbonate. We found that it is greatly affected by the structure,
The present invention has been accomplished by finding that the surface of an optical disk substrate injection-molded from an aromatic polycarbonate containing a specific amount is less likely to be charged, including during transportation after molding.

That is, the present invention is obtained by a transesterification reaction between an aromatic dihydroxy compound and a carbonic acid diester, and has the following general formula (1):

[0011]

[Chemical 2]

(In the formula, R ^{1 to} R ⁵ are each independently
It represents a hydrogen atom, a fluorine atom, or a perfluoroalkyl group having 1 to 20 carbon atoms. However, not all of R ^{1 to} R ⁵ are hydrogen atoms at the same time. ), The terminal structure represented by
An optical disk substrate formed by injection molding of an aromatic polycarbonate resin having a molar ratio to the total terminal structure of 0.1 to 99% and a viscosity average molecular weight of 10,000 to 23,000, and such a substrate were used. A write-once optical disc.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below. Aromatic Polycarbonate The aromatic polycarbonate according to the present invention is a polymer containing a repeating unit represented by the following general formula as a main component and a predetermined amount of the terminal group represented by the general formula (1).

[0014]

[Chemical 3]

(In the formula, W is a single bond, an alkylene group having 1 to 8 carbon atoms, an alkylidene group having 2 to 8 carbon atoms, and 5 to 5 carbon atoms.
15 cycloalkylene groups, C5-C15 cycloalkylidene groups, -O-, -S-, -CO-, -SO-,
And —SO ₂ — are each a divalent group selected from the group consisting of, and X and Y represent a halogen atom or a hydrocarbon group having 1 to 6 carbon atoms. p and q are integers of 0-2. X and Y and p and q may be the same or different. ).

The aromatic polycarbonate resin of the present invention has a viscosity average molecular weight of 10,000 to 23,000.
Must be within the range. Viscosity average molecular weight is 1
If it is less than 10,000, the strength of the substrate is remarkably lowered, and if it exceeds 23,000, the birefringence during injection molding is remarkably increased, which is not desirable. The viscosity average molecular weight should preferably be chosen between 13,000 and 18,000. The viscosity average molecular weight (M) used here is 2 for a solution using methylene chloride as a solvent, using an Ostwald viscometer.
The intrinsic viscosity (η) at 0 ° C. was measured, and Sc shown below was used.
It is calculated from the Hnell viscosity formula.

[0017]

[Equation 1] (η) = 1.23 × 10 ⁻⁴ M ^0.83

When the polycarbonate resin is a polymer mixture using two or more kinds of aromatic dihydroxy compounds, the viscosity average molecular weight of the polymer mixture is similarly determined using the above formula. Such an aromatic polycarbonate can be obtained by a transesterification reaction using an aromatic dihydroxy compound and a carbonic acid diester as raw materials in the presence of a transesterification catalyst. The aromatic dihydroxy compound used in the present invention is usually represented by the following general formula (2).

[0019]

[Chemical 4]

(In the formula, W is a single bond, an alkylene group having 1 to 8 carbon atoms, an alkylidene group having 2 to 8 carbon atoms, and 5 to 5 carbon atoms.
15 cycloalkylene groups, C5-C15 cycloalkylidene groups, -O-, -S-, -CO-, -SO-,
And —SO ₂ — are each a divalent group selected from the group consisting of, and X and Y represent a halogen atom or a hydrocarbon group having 1 to 6 carbon atoms. p and q are integers of 0-2. X and Y and p and q may be the same or different. ).

Examples of the aromatic dihydroxy compound represented by the general formula (3) include bis (4-hydroxyphenyl) methane, 2,2-bis (4-hydroxyphenyl) propane and 2,2-bis (4). -Hydroxy-3-methylphenyl) propane, 2,2-bis (4-hydroxy-3-t-butylphenyl) propane, 2,2-bis (4-hydroxy-3,5-dimethylphenyl) propane, 2, 2-bis (4-hydroxy-3,5-dibromophenyl) propane, 4,4-bis (4-hydroxyphenyl) heptane, 1,1-bis (4-hydroxyphenyl) cyclohexane, 4,4′-dihydroxybiphenyl , 3,3 ', 5,5'-tetramethyl-4,4'-
Examples thereof include dihydroxybiphenyl, bis (4-hydroxyphenyl) sulfone, bis (4-hydroxyphenyl) sulfide, bis (4-hydroxyphenyl) ether, and bis (4-hydroxyphenyl) ketone.
Particularly preferred is 2,2-bis (4-hydroxyphenyl) propane (hereinafter abbreviated as "bisphenol A"). These aromatic dihydroxy compounds may be used alone or as a mixture of two or more kinds.

The carbonic acid diester used in the present invention is usually represented by the following general formula (3).

[0023]

[Chemical 5]

(In the formula, A'is an aliphatic or aromatic hydrocarbon group having 1 to 18 carbon atoms which may have a substituent, and 2 '
The two A'may be the same or different. ). Examples of the carbonic acid diester represented by the general formula (3) include aliphatic carbonates such as dimethyl carbonate, diethyl carbonate and di-t-butyl carbonate, and aromatic carbonates such as diphenyl carbonate and biphenyl phenyl carbonate. However, diphenyl carbonate is particularly preferable. These carbonic acid diesters may be used alone or in combination of two or more.

For example, when bisphenol A is used as the aromatic dihydroxy compound and diphenyl carbonate is used as the carbonic acid diester, the amount of these raw materials used is 1.001 to 1.3 mol based on 1 mol of bisphenol A. , Preferably 1.0
It is preferably used in an amount of 2 to 1.20. When the molar ratio is less than 1.001, the number of terminal hydroxyl groups of the produced aromatic polycarbonate tends to increase, and the thermal stability of the polymer tends to deteriorate, and when the molar ratio is more than 1.3, the same conditions are satisfied. Under the conditions, the rate of the transesterification reaction is lowered, and it tends to be difficult to produce an aromatic polycarbonate having a desired molecular weight.

A transesterification catalyst is used in the transesterification reaction between the aromatic dihydroxy compound and the carbonic acid diester. An alkali metal compound and / or an alkaline earth metal compound is used as the catalyst, and a basic compound such as a basic boron compound, a basic phosphorus compound, a basic ammonium compound, or an amine compound is additionally used in combination. It is possible, but in terms of physical properties and handling,
It is particularly preferred that the alkali metal compounds and / or alkaline earth metal compounds are used alone.

[0027] The catalyst amount, the aromatic dihydroxy compound to 1 mol, is preferably used in a range of 1 × 10 ^-7 to 9 × 10 ^-7 mol, more preferably 1.5
In the range of × 10 ^over 7 to 8 × 10 ^-7 mol, particularly preferably in a range of 2 × 10 ^-7 to 7-× 10 ^-7 mol. If it is less than this amount, the polymerization activity required for producing a polycarbonate having a predetermined molecular weight and terminal hydroxyl group tends to not be obtained, and if it is more than this amount, the polymer hue deteriorates and the number of branches increases. Moldability tends to be impaired.

Examples of the alkali metal compound include sodium hydroxide, potassium hydroxide, lithium hydroxide, cesium hydroxide, sodium hydrogen carbonate, potassium hydrogen carbonate, lithium hydrogen carbonate, cesium hydrogen carbonate, sodium carbonate, potassium carbonate and carbonic acid. Lithium, cesium carbonate, sodium acetate, potassium acetate, lithium acetate, cesium acetate, sodium stearate, potassium stearate, lithium stearate, cesium stearate, sodium borohydride, potassium borohydride, lithium borohydride, hydride Cesium boron, sodium phenyl boride, potassium phenyl boride, lithium phenyl boride, cesium phenyl boride, sodium benzoate, potassium benzoate, lithium benzoate,
Cesium benzoate, disodium hydrogen phosphate, 2 potassium hydrogen phosphate, 2 lithium hydrogen phosphate, 2 cesium hydrogen phosphate, 2 sodium phenyl phosphate, 2 potassium phenyl phosphate, 2 lithium phenyl phosphate, 2 phenyl phosphate Cesium, sodium, potassium, lithium, cesium alcoholate, phenolate, bisphenol A
2 sodium salt, 2 potassium salt, 2 lithium salt, 2 cesium salt and the like.

As the alkaline earth metal compound,
For example, calcium hydroxide, barium hydroxide, magnesium hydroxide, strontium hydroxide, calcium hydrogen carbonate, barium hydrogen carbonate, magnesium hydrogen carbonate, strontium hydrogen carbonate, calcium carbonate, barium carbonate, magnesium carbonate, strontium carbonate, calcium acetate, acetic acid. Examples thereof include barium, magnesium acetate, strontium acetate, calcium stearate, barium stearate, magnesium stearate, and strontium stearate.

Specific examples of the basic boron compound include tetramethylboron, tetraethylboron, tetrapropylboron, tetrabutylboron, trimethylethylboron, trimethylbenzylboron, trimethylphenylboron, triethylmethylboron, triethylbenzylboron and triethylphenyl. Boron, tributylbenzylboron, tributylphenylboron, tetraphenylboron, benzyltriphenylboron, methyltriphenylboron, sodium salts such as butyltriphenylboron, potassium salts, lithium salts, calcium salts, barium salts, magnesium salts, or strontium. Salt etc. are mentioned.

Examples of the basic phosphorus compound include triethylphosphine, tri-n-propylphosphine, triisopropylphosphine, tri-n-butylphosphine, triphenylphosphine, tributylphosphine,
Alternatively, a quaternary phosphonium salt and the like can be mentioned.

Examples of the basic ammonium compound include tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, trimethylethylammonium hydroxide,
Trimethylbenzylammonium hydroxide, trimethylphenylammonium hydroxide, triethylmethylammonium hydroxide, triethylbenzylammonium hydroxide, triethylphenylammonium hydroxide, tributylbenzylammonium hydroxide, tributylphenylammonium hydroxide, tetraphenylammonium hydroxide, benzyltri Examples thereof include phenylammonium hydroxide, methyltriphenylammonium hydroxide, butyltriphenylammonium hydroxide and the like.

Examples of amine compounds include 4-aminopyridine, 2-aminopyridine, N, N-dimethyl-4-aminopyridine, 4-diethylaminopyridine,
2-hydroxypyridine, 2-methoxypyridine, 4-
Methoxypyridine, 2-dimethylaminoimidazole,
2-methoxyimidazole, imidazole, 2-mercaptoimidazole, 2-methylimidazole, aminoquinoline and the like can be mentioned.

The aromatic polycarbonate according to the present invention is characterized in that it has terminal groups of the structure represented by the general formula (1) in a range of 0.1 to 99% in terms of molar ratio to all terminal groups. When the terminal of the structure of the general formula (1) is less than 0.1 mol% with respect to all the terminal groups, the effect of preventing peeling charge during injection molding and transfer charge during transportation becomes small.
If it is 9 mol% or more, the wettability of the dye with respect to the substrate is deteriorated and the dye is repelled to cause a defective phenomenon called a bright defect. The range of the terminal group of the structure of formula (1) is more preferably 3 to 50 mol%, particularly preferably 5 to 3
It is in the range of 0 mol%.

The aromatic polycarbonate according to the present invention having such a terminal structure uses the above aromatic dihydroxy compound and carbonic acid diester in the reaction system in the transesterification reaction in the presence of a transesterification catalyst. The phenol represented by the following general formula (4) is 1 mol% or more, preferably 1.2, with respect to the aromatic dihydroxy compound.
It can be produced by allowing it to be present in an amount of at least mol%, more preferably at least 1.5 mol%.

[0036]

[Chemical 6]

(In the formula, R ^{1 to} R ⁵ each independently represent a hydrogen atom, a fluorine atom, or a perfluoroalkyl group having 1 to 20 carbon atoms, provided that all of R ^{1 to} R ⁵ are hydrogen at the same time. It cannot be an atom.)

The phenols represented by the general formula (4) include 2-fluorophenol, 3-fluorophenol,
4-fluorophenol, 2-trifluoromethylphenol, 3-trifluoromethylphenol, 4-trifluoromethylphenol, 2,4-difluorophenol, 3,
4-difluorophenol, 3,5-difluorophenol, 3,5-bis (trifluoromethyl) phenol, or a fluorine atom or C _n F _{2n + 1} (n is an integer of 1 to 20) Any of phenols substituted with 1 to 5 fluoroalkyl groups may be used. Among these phenols, 3,5-bis (trifluoromethyl) phenol is preferable in terms of physical properties and handling. Further, if the carbon number of the perfluoroalkyl group exceeds 20, the alkyl group is likely to be cleaved by heating, and the presence of the resulting fluorine atom may hinder the transesterification reaction, which is not preferable. . Such phenols may be added in advance together with the above-mentioned raw materials, and may be added during the reaction or at the end of the reaction, but when added during the reaction or at the end of the reaction, the viscosity increases. As a result, the mixing and dispersibility with the oligomer or polymer deteriorates, so it is preferable to add it together with the above raw materials in advance.

The transesterification reaction is generally carried out in a multi-step process of two or more steps. Specifically, the reaction of the first step was carried out under reduced pressure of 9.3 × 10 ^{4 to} 1.33 × 10 ³ Pa.
The reaction is carried out at a temperature of 20 to 260 ° C., preferably 180 to 240 ° C. for 0.1 to 5 hours, preferably 0.1 to 3 hours. Then, the reaction temperature is raised while increasing the degree of pressure reduction of the reaction system, and finally 240 to 32 under reduced pressure of 133 Pa or less.
The polycondensation reaction is carried out at a temperature of 0 ° C. The reaction may be performed in a batch system, a continuous system, or a combination of a batch system and a continuous system, and the apparatus used may be a tank type, a tube type,
Alternatively, any type of tower type may be used.

At the end of the polymerization reaction by transesterification of the aromatic dihydroxy compound and the carbonic acid diester, in order to deactivate the transesterification catalyst, a sulfonic acid compound or its precursor is added to the acidic compound or its precursor as a deactivator. More preferably, p-toluenesulfonic acid, methyl p-toluenesulfonate, butyl p-toluenesulfonate and the like are more preferable. These may be used alone or in combination of two or more.

The amount of addition of these acidic compounds or their precursors is 0.1 to 50 times, preferably 0.5 to 50 times the neutralization amount of the basic transesterification catalyst used in the polycondensation reaction.
It is used in the range of up to 30 times mol. The timing of adding the acidic compound or its precursor may be any time after the polycondensation reaction, and there is no particular limitation on the addition method, depending on the properties of the acidic compound or its precursor or desired conditions,
Any method such as a method of directly adding, a method of dissolving in a suitable solvent and a method of using a master batch in the form of pellets or flakes may be used. Further, to the aromatic polycarbonate of the present invention, additives such as a stabilizer, a UV absorber, a release agent and a coloring agent may be added within a range that does not impair the effects of the present invention.

Molded Substrate The optical disk such as CD, DVD or CD-R or DVD-R of the present invention is produced by injection molding of the aromatic polycarbonate having the above-mentioned specific end structure, and is formed into concentric circles called a groove. A molded substrate having a plurality of arranged guide grooves is used as a material. At the time of this injection molding, the shape of the submicron-sized pits and grooves pre-engraved on a predetermined stamper is the surface of a disk-shaped transparent molded substrate (referred to as "signal surface" in this specification). It is obtained by faithfully transferring to.

As a typical write-once optical disk such as a write- once optical disk CD-R or DVD-R, for example, a dye recording layer, a reflective layer, and a protective layer are laminated in this order on the above-mentioned molded substrate. In addition to the CD-R type optical disc having the configuration, a laminated body including a dye recording layer, a reflection layer, and a protective layer optionally provided on the molded substrate and a disc-shaped substrate (a dummy plate, the molded substrate may be used. And the recording layer is on the inner side with an adhesive, and a DVD-R type optical disc, and two write-once type optical disc substrates in which at least a dye recording layer is formed on the molded substrate. Recording layer (dye layer)
There is a DVD-R type optical disc having a structure in which both of them are on the inside by an adhesive. The thickness of the write-once type optical disc substrate having such a laminated structure is 0.
It is preferably 2 mm or more and 0.6 mm or less.

The substrate taken out from the molding machine is cooled by a cooling stage installed inside the clean booth. After that, the substrate is taken out from the cooling stage and conveyed to the dye solution coating step. The dye is usually applied by using a spin coating method to apply a dye solution in which an organic dye is dissolved in an organic solvent so as to fill the groove formed on the signal surface of the molded substrate. The spin coating method is generally carried out according to the following procedure using a spin coating device including a coating liquid applying device (dispensing nozzle), a spinner head, a shatterproof wall, and an exhaust device. First, the molded substrate is placed on the spinner head, and then, while rotating the spinner head by the drive motor, on the surface of the inner peripheral portion of the substrate, preferably within 2 to 3 mm from the innermost peripheral edge of the groove. The coating liquid is supplied to the position from the nozzle of the coating liquid applying device. The coating liquid supplied onto the substrate is radially cast on the outer peripheral side by centrifugal force to form a coating film. During the spin coat operation, a dry gas such as air is introduced through an opening (gas introduction part) provided above the shatterproof wall, the gas is circulated over the coating film, and exhausted from below the spin coater. . By the circulation of this gas, the solvent is removed from the coating film and the coating film is dried. If necessary, the substrate is put into a drying oven called baking to remove the residual solvent as completely as possible.

In the case of the write-once optical disc, the dye is
A dye having an absorption region in the laser light wavelength range (300 to 850 nm) is selected. Specifically, azo dyes, cyanine dyes, phthalocyanine dyes, azurenium dyes, squarylium dyes, polymethine dyes, pyrylium dyes, thiopyrylium dyes, indoaniline dyes, naphthoquinone dyes, anthraquinone dyes, triallylmethane dyes, aminium dyes, diimonium dyes, Examples thereof include metal chelate dyes composed of an azo ligand compound and a metal, metal complexes and the like, and mixtures thereof. Preferred are organic dyes of azo type, cyanine type and phthalocyanine type. These dyes have excellent signal sensitivity, are easily dissolved in a solvent, have good light resistance, and make it possible to obtain a high-quality write-once optical disc.

Specific examples of the organic solvent for the dye solution include esters such as butyl acetate and cellosolve acetate, ketones such as methyl ethyl ketone, cyclohexanone and methyl isobutyl ketone, dichloromethane, 1,
Chlorinated hydrocarbons such as 2-dichloroethane and chloroform, amides such as dimethylformamide, hydrocarbons such as cyclohexane, ethers such as tetrahydrofuran, ethyl ether and dioxane, ethanol,
Alcohols such as n-propanol, isopropanol, n-butanol, diacetone alcohol, 2,
Fluorine-based solvents such as 2,3,3-tetrafluoropropanol and glycol ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether and propylene glycol monomethyl ether can be exemplified. These solvents may be used alone or in combination of two or more in consideration of the solubility of the dye used. Preferred are fluorine-based solvents such as 2,2,3,3-tetrafluoropropanol, octafluoropentanol and dibutyl ether.

Further, as a reflection layer on the surface of the dye recording layer,
A thin film of Ag, Au, or the like is formed by a method such as a sputtering method. If necessary, the surface of the reflective layer may be coated with a protective film to obtain a laminate having the protective layer formed thereon. In the case of CD-R, it is formed of a single plate, but DVD-
In the case of R, high density can be achieved by bonding the above two substrates together.

[0048]

EXAMPLES The present invention will be described below according to examples, but the present invention is not limited to the scope of the following examples.
In the examples, all parts,% and ppm are based on weight unless otherwise specified. The methods for measuring the physical properties of aromatic polycarbonates in the following examples are as follows. Ratio of end groups of formula (1) in all end groups (unit: mol
%): 0.02 g of an aromatic polycarbonate sample was dissolved in 0.4 ml of chloroform and ¹ H-N was added at 30 ° C.
The number of terminal hydroxyl groups and the number of terminal phenyl groups were determined using MR (JNM-Al400 manufactured by JEOL Ltd.). Further, the total number of terminal groups was calculated by gel permeation chromatography (GPC manufactured by Shimadzu Corporation), and the following formula (i) was used to calculate the formula (1)
The ratio of the terminal groups of was determined.

[0049]

[Equation 2]   Ratio (mol%) of terminal groups of formula (1) = {(total number of terminal groups-number of terminal hydroxyl groups-terminal flux) Number of units) / Total number of end units} × 100 (i)

Example 1 (Preparation of aromatic polycarbonate) Equipped with condenser
In a stainless steel 20 liter vertical stirring reactor,
Bisphenol A 2283g (10.0 mol), diphe
Nyl carbonate 2290 g (10.7 mol), 3,5
-Bis (trifluoromethyl) phenol 89.7g
(0.39 mol, based on bisphenol A, 3.9 mol
%), 0.01N sodium hydroxide as a catalyst 0.7
ml (7 × 10 for 1 mol of bisphenol A) ^-6Mo
Was charged and the atmosphere was replaced with nitrogen. 220 this mixture
After melting the raw material monomer at 40 ℃ for 40 minutes, 220 ℃
/1.33 x 10^Four60 minutes at Pa, 240 ° C / 2.00
× 10³60 minutes at Pa, 40 at 270 ° C / 66.7 Pa
After reacting for minutes, butyl p-toluenesulfonate (touch)
2 times the molar amount of sodium hydroxide used as a medium
The amount) was added as a catalyst deactivator to terminate the reaction. That
As a result, an aromatic polycarbonate having a viscosity average molecular weight of 14,500
A nate was obtained and cut into a pellet with a cutter.
The viscosity average molecular weight (M
v), the structure of formula (1) and the proportion of end groups are shown in Table-1.
It was

(Production of Molded Substrate) The obtained pellets are
Injection molding was performed under the following conditions to obtain a molded substrate. Molding machine: Sumitomo Heavy Industries DISK3 Mold: 12cmφ CD, DVD mold Molding substrate thickness: 1.2mm Stamper groove depth: 160nm Stamper groove pitch: 0.80μm Maximum cylinder temperature of molding machine: 360 ° C Stamper Set temperature of the mold on which the is installed: 13
0 ° C. Injection time: 0.1 seconds Cooling time: 7.0 seconds Screw rotation speed: 360 rpm Screw diameter: 25 mm φ Mold clamping force: Injection, 20 T during holding pressure, 25 T during cooling

(Preparation of write-once type optical disk) The substrate molded under the above conditions was taken out from the mold and then cooled by 18 cooling stages. 50 of the obtained substrate
3m from the innermost circumference of the groove while rotating at rpm
A 5% solution of an azo dye, octafluoropentanol, was dropped from the nozzle onto the inner peripheral portion of the inside of m. The coating liquid supplied onto the substrate was radially cast on the outer peripheral side by increasing the rotation speed to 5000 rpm to form a coating liquid filled with grooves. Air was introduced through an opening (gas inlet) provided above the coater and exhausted from below the spin coater to volatilize the solvent. Then 9
The substrate was placed in a drying oven kept at 5 ° C. and dried for 15 minutes to remove the residual solvent, thus completing the formation of the dye recording layer. Then, Ag was sputtered on the surface of the dye recording layer and further coated with a protective film to obtain a CD-R write-once type optical disc.

Evaluation method: The voltage and birefringence of a substrate obtained by injection-molding a resin were measured by the following method, and the presence or absence of bright defects was measured for the write-once type optical disk. It was shown to. (1) Birefringence oak automatic birefringence measuring device (Oak Co., Ltd., trade name A
DR-130N), the light was made incident vertically on the substrate, and the measurement was performed using He-Ne laser light having a wavelength of 632.8 nm. The maximum absolute value at four points in the radial direction was defined as birefringence.

(2) Charge voltage Measure the charge voltage at a position 10 cm directly below the 18th cooling stage. Charge voltage measuring device is KSD-0 made by Kasuga Electric
102 was used. (3) Presence or absence of bright defect Visually observing the dye recording layer formed on the substrate after dye coating, and a part where the dye is partially thin is defined as a bright defect,
The presence or absence thereof was investigated.

Example 2 In Example 1, 3,5-bis (trifluoromethyl)
Example 1 except that 44.8 g (0.20 mol, 2.0 mol% based on bisphenol A) of phenol was used.
An optical disc was obtained in the same manner as in. The evaluation results are shown in Table-1.

Example 3 The procedure of Example 1 was repeated except that the cyanine dye solution was used instead of the azo dye solution.
I got an optical disc. The evaluation results are shown in Table-1.

Example 4 An optical disk was obtained in the same manner as in Example 1, except that the phthalocyanine dye solution was used instead of the azo dye solution. The evaluation results are shown in Table-1.

Example 5 In Example 1, the substrate thickness was changed to 0.6 mm instead of 1.2 mm, and the obtained substrate after dye coating and Ag sputtering and the substrate before dye coating were pasted with an acrylic adhesive. An optical disc was obtained in the same manner as in Example 1 except that they were combined. The evaluation results are shown in Table-1.

Example 6 In Example 1, 3,5-difluorophenol was mixed with 5
0.7 g (0.39 mol, relative to bisphenol A,
3.9 mol%)
I got an optical disc. The evaluation results are shown in Table-1.

Example 7 In Example 1, 3,5-bis (perfluorononyl)
An optical disk was obtained in the same manner as in Example 1 except that 401.7 g (0.39 mol, 3.9 mol% based on bisphenol A) of phenol was used. The evaluation results are shown in Table-1.

Comparative Example 1 In the production of aromatic polycarbonate in Example 1,
An optical disk was obtained in the same manner as in Example 1 except that 3,5-bis (trifluoromethyl) phenol was not used. The evaluation results are shown in Table-1.

Comparative Example 2 In Comparative Example 1, when the aromatic polycarbonate was produced,
An optical disk was obtained in the same manner as in Comparative Example 1 except that the reaction was performed at 290 ° C./60.0 Pa for 60 minutes in the final stage of the reaction. The evaluation results are shown in Table-1.

Comparative Example 3 In Example 1, 3,5-bis (trifluoromethyl)
An optical disk was obtained in the same manner as in Example 1 except that 0.036 g (0.00016 mol, 0.0016 mol% based on bisphenol A) of phenol was used. The evaluation results are shown in Table-1.

COMPARATIVE EXAMPLE 4 In Example 1, 3,5-bis (trifluoromethyl)
An optical disk was obtained in the same manner as in Example 1 except that 362.8 g (1.58 mol, 15.8 mol% based on bisphenol A) of phenol was used. Table of evaluation results
Shown in 1.

[0065]

[Table 1]

[0066]

EFFECTS OF THE INVENTION According to the present invention, a substrate produced by injection molding by using an aromatic polycarbonate having a fluorine atom introduced in the terminal group has a peeling charge because the releasability is improved when the substrate is peeled from the stamper. And at the same time the friction coefficient of the substrate surface is reduced, so that the charging due to the friction with the air generated during transportation is reduced, and as a result, it is possible to provide a substrate for an optical disc with less charging and a small birefringence of the substrate. it can. By using such a substrate, in particular, a write-once type optical disc having no bright defects can be manufactured.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G11B 7/24 526 B29K 69:00 // B29K 69:00 B29L 17:00 B29L 17:00 C08L 69:00 C08L 69:00 B41M 5/26 Y (72) Inventor Hiroyoshi Maruyama 5-6-2 Higashi-Hachiman, Hiratsuka-shi, Kanagawa Sanryo Engineering Plastics Co., Ltd. Technical Center (72) Haruhiko Kurokawa Higashi-Hachiman, Hiratsuka-shi, Kanagawa 5-6-2 Sanryo Engineering Plastics Co., Ltd. Technical Center F-term (reference) 2H111 EA03 EA12 EA22 FA37 FB42 FB43 FB45 4F071 AA50 AA81 AF30 AF31 AH19 BB05 BC03 4F206 AA28A AA28C AH79 JA07 JF01 JW01 AB01 A29A01 AE05 BB08A BB08B BB09A BB10A BB11A BB11B BB12A BB13A BD08 BD09A BE04 BE05A B F11 BF13 BF14A BG06X BG07X BG08X BG20X BH02 DB07 DB11 DB13 HC03 HC04A HC04C HC05A HC05B JA091 JA111 JA121 JA261 JB171 JC411 KC04 KE02 5D029 JA04 KA07 KC09 RA06

Claims (6)

[Claims] 1. A transesterification reaction between an aromatic dihydroxy compound and a carbonic acid diester, which is represented by the following general formula (1): (In the formula, R ^{1 to} R ⁵ each independently represent a hydrogen atom, a fluorine atom, or a perfluoroalkyl group having 1 to 20 carbon atoms, provided that all of R ^{1 to} R ⁵ are hydrogen atoms at the same time. Aromatic polycarbonate resin having a terminal structure represented by the formula (1) in a molar ratio of 0.1 to 99% based on the total terminal structure and a viscosity average molecular weight of 10,000 to 23,000. An optical disk substrate formed by injection molding. 2. The optical disk substrate according to claim 1, wherein the molar ratio of the terminal structure represented by the general formula (1) to the total terminal structure is in the range of 1 to 50%. 3. A write-once type optical disc having at least a dye recording layer formed on the optical disc substrate according to claim 1. 4. A dye recording layer by applying a dye solution in which an azo, cyanine or phthalocyanine organic dye is dissolved in an organic solvent to the signal surface of the optical disc substrate according to claim 1 or 2. Write-once type optical disc formed by forming. 5. An optical disc obtained from the optical disc substrate according to claim 1 or 2, wherein at least one substrate is provided with a dye recording layer, and the two substrates are formed with a dye recording layer. A write-once optical disc having a structure in which the optical disc is attached inside. 6. The aromatic polycarbonate resin according to claim 1 or 2.