JP2000319378A - Polycarbonate resin molding material for optical use and optical disk base made of the material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a polycarbonate resin molding material for optical use capable of keeping high reliability over a long period and improving the productivity of disk base by reducing the content of monofunctional phenols in a polycarbonate resin. SOLUTION: This polycarbonate resin contains <=50 ppm of monofunctional phenol (preferably alkyl-substituted or phenylalkyl-substituted phenols). The polycarbonate resin has a viscosity-average molecular weight of preferably 10,000-22,000. The optical disk base produced by using the molding material has extremely little generation of small white spots even after keeping under high-temperature and humidity condition over a long period and is useful as a base for DVD(digital versatile disk) such as CD-R, CD-RW and digital video disk.

Description

DETAILED DESCRIPTION OF THE INVENTION

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical polycarbonate resin molding material and an optical disk substrate capable of maintaining high reliability for a long period of time and improving substrate productivity.

[0001]

2. Description of the Related Art Optical disks for recording and reproducing information by irradiating a laser beam include digital audio disks (so-called compact disks), optical video disks (so-called laser disks), various write-once disks, magneto-optical disks, and phase-change disks. Changeable disks and the like have been put to practical use.

[0002] Among them, compact discs and laser discs are read-only (Read Only Memory).
(y: ROM) type optical disk. In these optical disks, pits corresponding to information signals are formed in an uneven shape on a transparent substrate, and an Al reflective layer is formed thereon with a thickness of 40 nm or more. In such an optical disc, an information signal is reproduced by detecting a change in reflectance caused by optical interference generated in the pit.

On the other hand, a write-once optical disc has an R (Recordable) on which arbitrary information can be written by a user.
e) type optical disk, a magneto-optical disk and a phase change type disk are RAMs (Random Access Memory) in which arbitrary information can be repeatedly written.
y) type optical disc.

That is, the R-type optical disk is composed of a write-once type recording layer on which an optical characteristic is irreversibly changed or an uneven shape is formed by irradiating a laser beam on a transparent substrate. As the recording layer, for example, a cyanine-based, phthalocyanine-based, or azo-based organic dye that is decomposed by heating by laser light irradiation, changes its optical constant, and causes deformation of the substrate due to volume change is used.

A magneto-optical disk allows a user to repeatedly write and erase information.
This is a rewritable optical disk that has a T
A perpendicular magnetization film having a magneto-optical effect (for example, the Kerr effect) such as a b-Fe-Co amorphous alloy thin film is formed. In this magneto-optical disk, recording pits are formed by magnetizing a small region of a perpendicular magnetization film upward or downward in response to an information signal. The information signal is reproduced by utilizing the fact that the rotation angle θk (Kerr rotation angle) of the linearly polarized light in the reflected light differs depending on the direction of magnetization of the perpendicular magnetization film.

A phase-change disk is a rewritable disk like a magneto-optical disk. For example, a phase-change disk exhibits a crystalline state in an initial state, and changes its phase to an amorphous state when irradiated with a laser beam. A phase change material or the like is used. In this recording layer, recording pits are formed by phase-changing a minute area in response to an information signal.
The information signal is reproduced by detecting a change in the reflectance between the amorphous portion corresponding to the pit and the other crystal region.

In such a magneto-optical disk or a phase-change disk, both sides of the recording layer are sandwiched between transparent dielectric layers for the purpose of preventing the recording layer from being oxidized and increasing the signal modulation degree due to multiple interference, and further thereon. In many cases, a four-layer structure in which Al reflective layers are stacked is adopted. In addition, as the dielectric layer, a silicon nitride film, a Zn—SiO ₂ mixed film, or the like is used.

Recently, studies on using such an optical disk for digital video recording have been actively conducted, and a digital versatile disk (DVD) has been developed as such an optical disk. This DVD has a diameter of 120 mm, which is the same as a CD, and records video information equivalent to one movie, so that it can be reproduced with image quality comparable to that of a current television.

[0009] In order to record such video information on an optical disk, a recording capacity of, for example, 6 to 8 times that of a CD is required. For this reason, in DVD, the laser wavelength is shortened to 635-650 nm compared to 780 nm in CD, and the numerical aperture NA of the objective lens is 0.45 in CD.
On the other hand, by increasing the recording pitch to 0.52 or 0.6, the track pitch and the shortest recording mark length of the pit are reduced, and the recording density is increased.

[0010] Of these, an increase in the numerical aperture NA of the objective lens reduces the allowable amount of warpage of the disk substrate. For this reason, in the case of DVD, the thickness of the substrate is reduced to 0.6 mm from 1.2 mm of the CD, whereby
The distance that the laser light passes through the disk substrate is shortened to compensate for the allowable amount of warpage (Nikkei Electronics, February 27, 1995 No. 630).
Then, as described in JP-A-6-274940, in order to compensate for a decrease in disk strength due to further thinning of the substrate, the substrate is further laminated on a recording layer formed on the substrate, so-called, Adhered structure is adopted. As the recording layer of the bonded optical disc, a ROM-type recording layer used in the above-described single-plate configuration,
Either the R-type recording layer or the RAM-type recording layer can be adopted.

Further, the bonded optical disk includes a single-sided bonded optical disk using only one surface thereof,
There is a double-sided bonded optical disk using both sides. For the optical disk substrates as described above, polycarbonate resins excellent in moldability, strength, light transmittance, moisture resistance, and the like are often used.

However, the polycarbonate resin having such excellent properties also has a disadvantage that it is easily hydrolyzed under high temperature and high humidity, and is liable to decrease in molecular weight and impact strength. Further, if the substrate is left under high temperature and high humidity for a long period of time, there is a disadvantage that minute white spots are generated on the substrate and the long-term reliability is impaired.

On the other hand, with the spread of optical disk substrates in recent years, there has been an increasing demand for improved substrate productivity. Resins contain various volatile components, and if molding is performed for a long period of time, various components accumulate on a mold, a stamper, and the like, leading to deterioration of substrate characteristics such as optical and mechanical characteristics.
Further, there is also a problem that the above various substrate characteristics are deteriorated by long-time molding. For this reason, continuous molding must be temporarily stopped in order to clean the mold and the stamper, which has had an adverse effect on the improvement in productivity.

[0014]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above problems, and as a result of intensive studies on the problems, it has been found that the content of monofunctional phenols in a polycarbonate resin is reduced. It has also been found that an optical disc can be obtained which can control deterioration of a substrate made of a polycarbonate resin extremely effectively and maintain high reliability for a long period of time. In addition, they have also found that the reduction of the monofunctional phenols leads to a reduction in volatile components at the same time, and that an optical polycarbonate resin molding material and an optical disk substrate that can improve substrate productivity can be obtained.

[0015]

The present invention is achieved by an optical polycarbonate resin molding material and an optical disk substrate comprising a polycarbonate resin having a monofunctional phenol content of 50 ppm or less.

In the present invention, CD-R, CD-R
W, MO, digital video disk, DVD-ROM,
Digital versatile discs (DVs represented by DVD-audio, DVD-R, DVD-RAM, etc.)
In order to obtain sufficient reliability as a substrate for an optical disk of D), particularly a disk substrate used for a high-density optical disk such as a DVD substrate, and to improve the substrate productivity, a molding material used for molding the substrate ( It is necessary that the content of monofunctional phenols in the aromatic polycarbonate resin) is 50 ppm or less. Here, the content of monofunctional phenols refers to those which are added as a terminal stopper during the polymerization reaction of the polycarbonate resin and remain as a simple substance in the resin, and those which are released from the raw materials during the polymerization reaction and are simplex in the resin. Shows the content of the remaining components.

When the content of monofunctional phenols is suppressed to 50 ppm or less, generation of minute white spots on the substrate and the number of times of cleaning the mold and the stamper can be minimized. Further, when a material having a monofunctional phenol content of more than 50 ppm is used, sufficient reliability and substrate productivity cannot be obtained. The content of monofunctional phenols is 50p
pm or less, preferably 30 ppm or less, more preferably 20 ppm or less can provide a certain effect. Most preferred is 10 ppm or less.

The polycarbonate resin used in the present invention is usually obtained by reacting a dihydric phenol with a carbonate precursor by an interfacial polymerization method or a melting method.
Representative examples of the dihydric phenol used here include hydroquinone, resorcinol, 4,4'-dihydroxydiphenyl, bis (4-hydroxyphenyl)
Methane, bis (4-hydroxy-3,5-dimethyl)
Phenyl @ methane, 1,1-bis (4-hydroxyphenyl) ethane, 1,1-bis (4-hydroxyphenyl) -1-phenylethane, 2,2-bis (4-hydroxyphenyl) propane (commonly known as bisphenol A) ),
2,2-bis {(4-hydroxy-3-methyl) phenyl} propane, 2,2-bis} (4-hydroxy-3,5
-Dimethyl) phenyl {propane, 2,2-bis} (3,
5-dibromo-4-hydroxy) phenyl} propane,
2,2-bis} (3-isopropyl-4-hydroxy)
Phenyl {propane, 2,2-bis} (4-hydroxy-3-phenyl) phenyl} propane, 2,2-bis (4-hydroxyphenyl) butane, 2,2-bis (4
-Hydroxyphenyl) -3-methylbutane, 2,2-
Bis (4-hydroxyphenyl) -3,3-dimethylbutane, 2,4-bis (4-hydroxyphenyl) -2-
Methylbutane, 2,2-bis (4-hydroxyphenyl) pentane, 2,2-bis (4-hydroxyphenyl) -4-methylpentane, 1,1-bis (4-hydroxyphenyl) cyclohexane, 1,1-bis (4-hydroxyphenyl) -4-isopropylcyclohexane, 1,1-bis (4-hydroxyphenyl) -3,3,
5-trimethylcyclohexane, 9,9-bis (4-hydroxyphenyl) fluorene, 9,9-bis {(4-
(Hydroxy-3-methyl) phenyl} fluorene, α,
α'-bis (4-hydroxyphenyl) -o-diisopropylbenzene, α, α'-bis (4-hydroxyphenyl) -m-diisopropylbenzene, α, α'-bis (4-hydroxyphenyl) -p-diisopropyl Benzene, 1,3-bis (4-hydroxyphenyl) -5,7
Dimethyladamantane, 4,4'-dihydroxydiphenylsulfone, 4,4'-dihydroxydiphenylsulfoxide, 4,4'-dihydroxydiphenylsulfide, 4,4'-dihydroxydiphenylketone, 4,
4'-dihydroxydiphenyl ether and 4,4 '
-Dihydroxydiphenyl ester and the like, and these can be used alone or in combination of two or more.

Bisphenol A, 2,2-bis {(4-hydroxy-3-methyl) phenyl} propane, 2,2-bis (4-hydroxyphenyl) butane,
2,2-bis (4-hydroxyphenyl) -3-methylbutane, 2,2-bis (4-hydroxyphenyl) -3,
3-dimethylbutane, 2,2-bis (4-hydroxyphenyl) -4-methylpentane, 1,1-bis (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane and α, α′-bis ( 4-hydroxyphenyl)
Homopolymers or copolymers obtained from at least one bisphenol selected from the group consisting of -m-diisopropylbenzene are preferred, and bisphenol A is particularly preferred.
And 1,1-bis (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane and bisphenol A, 2,2-bis {(4-hydroxy-3-methyl) phenyl} propane or α, α'-bis (4-
A copolymer with (hydroxyphenyl) -m-diisopropylbenzene is preferably used.

As the carbonate precursor, carbonyl halide, carbonate ester, haloformate and the like are used, and specific examples include phosgene, diphenyl carbonate and dihaloformate of dihydric phenol.

In producing the polycarbonate resin by reacting the dihydric phenol with the carbonate precursor by an interfacial polymerization method or a melting method, a catalyst, an antioxidant of the dihydric phenol and the like may be used as necessary. Is also good.
Further, the polycarbonate resin may be a branched polycarbonate resin obtained by copolymerizing a trifunctional or higher polyfunctional aromatic compound, or a polyester carbonate resin obtained by copolymerizing an aromatic or aliphatic bifunctional carboxylic acid,
Further, a mixture of two or more of the obtained polycarbonate resins may be used.

The reaction by the interfacial polymerization method is usually a reaction between dihydric phenol and phosgene, and is carried out in the presence of an acid binder and an organic solvent. As the acid binder, for example, an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide or an amine compound such as pyridine is used. As the organic solvent, for example, halogenated hydrocarbons such as methylene chloride and chlorobenzene are used. Further, for promoting the reaction, for example, a catalyst such as a tertiary amine such as triethylamine, tetra-n-butylammonium bromide, or tetra-n-butylphosphonium bromide, a quaternary ammonium compound, or a quaternary phosphonium compound may be used. it can. At that time, the reaction temperature is usually 0 to 40 ° C., the reaction time is preferably about 10 minutes to 5 hours, and the pH during the reaction is preferably maintained at 9 or more.

The reaction by the melting method is usually a transesterification reaction between a dihydric phenol and a carbonate ester,
This is carried out by a method in which a dihydric phenol and a carbonate ester are mixed while heating in the presence of an inert gas to distill off the resulting monofunctional phenols. The reaction temperature varies depending on the boiling point of the monofunctional phenols produced,
Usually, it is in the range of 120 to 350 ° C. In the latter stage of the reaction, the pressure of the system is reduced to about 10 to 0.1 Torr to facilitate the distillation of the monofunctional phenols formed. Since the monofunctional phenols generated during the reaction remain in the polycarbonate resin, a sufficient reaction time is required, and the reaction time is 1 to
It is about 4 hours.

Examples of the carbonate ester include an optionally substituted ester such as an aryl group having 6 to 10 carbon atoms, an aralkyl group or an alkyl group having 1 to 4 carbon atoms. Specific examples include diphenyl carbonate, ditolyl carbonate, bis (chlorophenyl) carbonate, m-cresyl carbonate, dinaphthyl carbonate, bis (diphenyl) carbonate, dimethyl carbonate, diethyl carbonate, dibutyl carbonate, and the like. Is preferred.

A polymerization catalyst can be used to increase the polymerization rate. Examples of the polymerization catalyst include sodium hydroxide, potassium hydroxide, alkali metal compounds such as sodium salt and potassium salt of dihydric phenol, and water. Alkaline earth metal compounds such as calcium oxide, barium hydroxide and magnesium hydroxide; nitrogen-containing basic compounds such as tetramethylammonium hydroxide, tetraethylammonium hydroxide, trimethylamine and triethylamine; alkoxides of alkali metals and alkaline earth metals Manganese, organic acid salts of alkali metals and alkaline earth metals, zinc compounds, boron compounds, aluminum compounds, silicon compounds, germanium compounds, organic tin compounds, lead compounds, osmium compounds, antimony compounds Compounds, titanium compounds, usually the esterification reaction, such as zirconium compounds, there can be used a catalyst used in the transesterification reaction. The catalyst may be used alone or in combination of two or more. The amount of the polymerization catalyst to be used is preferably 1 × 10 ⁻⁸ to 1 × 10 ⁸ per 1 mol of the starting dihydric phenol.
^-4 equivalents, more preferably 1 × 10 ^{−7 to} 5 × 10 ⁻⁴ equivalents.

In the polymerization reaction, in order to reduce the number of phenolic terminal groups, a terminal stopper other than monofunctional phenols, for example, bis (chlorophenyl) carbonate, bis (bromo) Compounds such as phenyl) carbonate, bis (nitrophenyl) carbonate, bis (phenylphenyl) carbonate, chlorophenylphenylcarbonate, bromophenylphenylcarbonate, nitrophenylphenylcarbonate, phenylphenylcarbonate, methoxycarbonylphenylphenylcarbonate and ethoxycarbonylphenylphenylcarbonate Is preferably added. Among them, 2-chlorophenylphenyl carbonate and 2-methoxycarbonylphenylphenyl are preferable, and 2-methoxycarbonylphenylphenyl is particularly preferably used.

In the polymerization reaction of the polycarbonate resin by the interfacial polymerization method, a monofunctional phenol is used as a terminal stopper. Monofunctional phenols are used as molecular terminators to control the molecular weight, and the resulting polycarbonate resin has a higher thermal stability than non-phenolic ones because the ends are blocked by groups based on monofunctional phenols. Is excellent. As such monofunctional phenols, monofunctional phenols represented by the following general formulas (1) to (3) can be shown.

[0028]

Embedded image [In the formula, A is a hydrogen atom or an alkyl group having 1 to 9 carbon atoms or a phenylalkyl group (1 carbon atom of the alkyl portion)
To 9), and r is an integer of 1 to 5, preferably 1 to 3].

[0029]

Embedded image

[0030]

Embedded image [Wherein, X represents -R-O-, -R-CO-O- or -R
—O—CO—, wherein R is a single bond or 1 carbon atom
Represents a divalent aliphatic hydrocarbon group of 10 to 10, preferably 1 to 5, and n represents an integer of 10 to 50. ]

Specific examples of the monofunctional phenol represented by the general formula (1) include, for example, phenol, isopropylphenol, p-tert-butylphenol,
-Cresol, p-cumylphenol and isooctylphenol.

The monofunctional phenols represented by the above general formulas (2) and (3) are phenols having a long-chain alkyl group or aliphatic polyester group as a substituent, and a phenol having a long-chain alkyl group or aliphatic polyester group is used. When the ends of the resin are blocked, they not only function as a terminator or a molecular weight regulator, but also improve the melt flowability of the resin and facilitate molding processing, as well as physical properties as a substrate, particularly of the resin. It has the effect of lowering the water absorption,
It is also preferably used because it has the effect of reducing the birefringence of the substrate.

The substituted phenols of the above general formula (2) are preferably those having n of 10 to 30, especially 10 to 26, and specific examples thereof include decylphenol, dodecylphenol, tetradecylphenol, hexadecylphenol and Octadecylphenol, eicosylphenol, docosylphenol, triacontylphenol and the like can be mentioned.

Further, as the substituted phenols of the above general formula (3), compounds wherein X is -R-CO-O- and R is a single bond are suitable, and n is 10-30, especially 10-10.
26 are preferred, examples of which include, for example, decyl hydroxybenzoate, dodecyl hydroxybenzoate, tetradecyl hydroxybenzoate, hexadecyl hydroxybenzoate, eicosyl hydroxybenzoate, docosyl hydroxybenzoate and tricontyl hydroxybenzoate. No.

Of these monofunctional phenols, monofunctional phenols represented by the above formula (1) are preferred, more preferably phenols substituted with alkyl or phenylalkyl, and particularly preferably p-tert.
-Butylphenol or p-cumylphenol.

These monofunctional phenolic terminal stoppers are desirably introduced at least 5 mol%, preferably at least 10 mol%, based on all terminals of the obtained polycarbonate resin. The terminal stoppers may be used alone or in combination of two or more.

The polycarbonate resin has a viscosity average molecular weight (M) of preferably 10,000 to 22,000, more preferably 12,000 to 20,000, and more preferably 13,000 to 20,000.
000 to 18,000 is particularly preferred. A polycarbonate resin having such a viscosity average molecular weight is preferable because sufficient strength is obtained as an optical material, and the melt fluidity during molding is good, and molding distortion is not generated. The viscosity average molecular weight referred to in the present invention is obtained by inserting the specific viscosity (η _sp ) obtained from a solution obtained by dissolving 0.7 g of a polycarbonate resin in 100 mL of methylene chloride at 20 ° C. into the following equation. η _sp /c=[η]+0.45×[η] ² c (where [η] is the intrinsic viscosity) [η] = 1.23 × 10 ^-4 M ^0.83 c = 0.7

The raw material polycarbonate resin is manufactured by a conventionally known method (interfacial polymerization method, melt polymerization method, etc.), and then subjected to alkali extraction or filtration in a solution state, or granulated raw material after granulation (desolvation). Is washed with a poor solvent and a non-solvent such as a ketone such as acetone, an aliphatic hydrocarbon such as hexane, and an aromatic hydrocarbon such as xylene to remove impurities and foreign matters such as low molecular weight components and unreacted components. Is preferred. Further, in the extrusion step (pelletizing step) of obtaining a pellet-like polycarbonate resin for use in injection molding, it is preferable to remove foreign matter by passing through a sintered metal filter having a filtration accuracy of 10 μm in a molten state. If necessary, it is also preferable to add additives such as a release agent such as a polyhydric alcohol fatty acid ester and an antioxidant such as a phosphorus compound. In any case, it is necessary to minimize the content of foreign materials, impurities, solvents and the like in the raw material resin before injection molding. As a method of reducing the content of monofunctional phenols, for example, after adding a monofunctional phenol, a catalyst is added and a sufficient reaction is performed, or a conventionally known ordinary method (solution polymerization method, melt polymerization method, etc.)
And then alkali extraction in a solution state, or granulation (desolvation) of the granular raw material, for example, ketones such as acetone, aliphatic hydrocarbons such as hexane, and polycarbonates such as aromatic hydrocarbons such as xylene It is preferable to remove by washing with a poor solvent and a non-solvent. These can also be combined. When an optical disk substrate is manufactured from the above polycarbonate resin, an injection molding machine (including an injection compression molding machine) is used. This injection molding machine may be a commonly used one. It is preferable to use a material made of a material having properties. Injection molding conditions include a cylinder temperature of 300 to 400 ° C and a mold temperature of 50 to
The temperature is preferably 140 ° C., whereby an optically excellent optical disk substrate can be obtained. The environment in the molding process
For the purposes of the present invention, it is preferred that it be as clean as possible. It is also important to sufficiently dry the material to be subjected to molding to remove water, and to take care not to cause stagnation which may cause decomposition of the molten resin. It is also important to take care not to use a substrate having an abnormality in birefringence, mechanical characteristics, etc. as a product or a test substrate.

The optical disc substrate made of the optical polycarbonate resin molding material according to the present invention has very little white spots even when kept under high temperature and high humidity conditions for a long time.
DR, CD-RW, MO, digital video disk,
DVD-ROM, DVD-audio, DVD-R, D
Digital versatile, represented by VD-RAM, etc.
It is excellent as a substrate of an optical disk of a disk (DVD), particularly a substrate of a DVD. The characteristics under the conditions of high temperature and high humidity are as follows. The disk is left in a constant temperature and humidity chamber controlled at a temperature of 80 ° C. and a relative humidity of 85% for 1000 hours, and has a size of 20 μm.
It is confirmed by checking the number of white spots generated above. The number of white spots generated on a disk obtained from the polycarbonate resin molding material according to the present invention was 2 per substrate having a diameter of 120 mm.
Or less, and preferably one or less.

[0040]

The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. The evaluation was performed according to the following method. (1) Monofunctional phenol content analysis Quantification was performed using high performance liquid chromatography (HPLC).

(2) Long-term reliability test Disk molding machine [DISK 3M manufactured by Sumitomo Heavy Industries, Ltd.]
III] optical disc substrate (diameter 120
mm, thickness 1.2 mm) at a temperature of 80 ° C and a relative humidity of 85.
%, The number of white spots having a size of 20 μm or more in the substrate was counted. This was performed for 25 optical disk substrates, and the average value was determined, and this was defined as the number of white spots.

(3) CD productivity test Injection molding machine, DISK3 M III manufactured by Sumitomo Heavy Industries, Ltd.
Attach a mold for exclusive use of CD to the mold, attach a stamper for pitted nickel CD to this mold, put the molding material into the hopper of the molding machine by automatic conveyance, cylinder temperature 340 ° C, mold temperature The molding was performed continuously at 70 ° C. After the start of continuous molding, the number of defective substrates produced increased due to abnormal birefringence and mechanical properties, and the number of molded substrates until the number of defective substrates per 100 units exceeded 10% was determined. The criteria for conforming product boards were as follows: the birefringence was ± 100 nm or less in a double pass, and the mechanical characteristics were ± 1.6 degrees in a radial warpage angle.

(4) DVD productivity test Injection molding machine, DISK3 M III manufactured by Sumitomo Heavy Industries, Ltd.
A mold for DVD is mounted on the mold, a pitted nickel DVD stamper is mounted on the mold, and the molding material is automatically fed into a hopper of a molding machine. The molding was continuously performed at 115 ° C., and the number of molded sheets was obtained in the same manner as in the CD productivity test. The criterion for judging the quality of a production board is that the birefringence is ± 100 nm or less in a double pass, and the mechanical properties are ±
The angle was set to within 0.8 degrees and the warp angle in the circumferential direction was set to within ± 0.3 degrees.

Example 1 A reactor equipped with a thermometer, a stirrer and a reflux condenser was charged with 219.4 parts of ion-exchanged water and 40% of a 48% aqueous sodium hydroxide solution.
After charging 2 parts, 57.5 parts (0.252 mol) of 2,2-bis (4-hydroxyphenyl) propane and 0.12 part of hydrosulfite were dissolved, 181 parts of methylene chloride was added, and the mixture was stirred. Phosgene 2 at 15-25 ° C
8.3 parts were blown in for 40 minutes. After completion of the phosgene blowing, 7.2 parts of a 48% aqueous sodium hydroxide solution and p
2.42 parts of -tert-butylphenol were added, stirring was started, 0.06 parts of triethylamine was added after emulsification, and the mixture was further stirred at 28 to 33 ° C for 10 minutes to complete the reaction.
After completion of the reaction, the product was diluted with methylene chloride, washed with water, acidified with hydrochloric acid, washed with water, and methylene chloride was evaporated by a kneader provided with an isolation chamber having a foreign-matter extraction port in a bearing portion.
A powder having a viscosity average molecular weight of 15,000 was obtained. 0.005% by weight of trisnonylphenyl phosphite and 0.03% by weight of glycerin monostearate are added to this powder.
Add-mix and vent-type twin-screw extruder [KT made by Kobe Steel Ltd.]
X-46] and melt-kneaded while degassing at a cylinder temperature of 240 ° C. to obtain pellets shown in Example 1 of Table 1 below.

CD and DV using these pellets
For the D substrate, a long-term reliability test and a productivity test were performed, and the number of white spots generated and the number of continuously formed sheets were obtained, respectively. The above results are shown in Table 1 together with the content of monofunctional phenols in the pellet.

Example 2 Raw material pellets were produced in the same manner as in Example 1 except that the stirring time at 28 to 33 ° C. was changed to 30 minutes, and CD and DVD substrates were formed and evaluated. The results are shown in Table 1 together with the content of monofunctional phenols in the pellet.

Example 3 10 L of acetone was added to 1 kg of the polycarbonate powder obtained in Example 1 and stirred at room temperature for 2 hours.
Raw material pellets were produced in the same manner as in Example 1 except that purified polycarbonate was obtained by drying under reduced pressure. Thereafter, CD and DVD substrates were formed in the same manner as in Example 1 and evaluated. The results are shown in Table 1 together with the content of monofunctional phenols in the pellet.

Example 4 Raw material pellets were produced in the same manner as in Example 3 except that the polycarbonate powder obtained in Example 2 was used, and CD and DVD substrates were molded and evaluated.
The results are shown in Table 1 together with the content of monofunctional phenols in the pellet.

Comparative Example 1 A powder was produced in the same manner as in Example 1 except that the reaction was terminated by stirring for 2 hours without adding triethylamine, and only water washing was carried out. Pellets shown in Comparative Example 1 were obtained from this powder in the same manner as in Example 1. Thereafter, CD and DVD substrates are formed in the same manner as in Example 1,
This was evaluated. The results are shown in Table 1 together with the content of monofunctional phenols in the pellet.

Comparative Example 2 Raw material pellets were produced in the same manner as in Example 1 except that stirring was continued for 3 hours without adding triethylamine, and CD and DVD substrates were formed and evaluated.
The results are shown in Table 1 together with the content of monofunctional phenols in the pellet. From these results, in order to obtain a highly reliable high-density optical disc substrate, it is necessary to reduce the content of monofunctional phenols contained in the optical polycarbonate resin molding material for substrate molding to 50 ppm or less. It is obvious.

[0051]

[Table 1]

[0052]

According to the molding material of the present invention, the content of monofunctional phenols contained in the material is as low as 50 ppm or less, high reliability can be maintained for a long time, and
An optical polycarbonate resin molding material and an optical disk substrate that can improve substrate productivity can be obtained. CD
The effects achieved by optical discs such as -R, CD-RW, MO, and digital versatile disc (DVD), especially DVDs, are also outstanding.

────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] June 22, 1999 (1999.6.2
2)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0026

[Correction method] Change

[Correction contents]

In the polymerization reaction, in order to reduce the number of phenolic terminal groups, a terminal stopper other than monofunctional phenols, for example, bis (chlorophenyl) carbonate, bis (bromo) Compounds such as phenyl) carbonate, bis (nitrophenyl) carbonate, bis (phenylphenyl) carbonate, chlorophenylphenylcarbonate, bromophenylphenylcarbonate, nitrophenylphenylcarbonate, phenylphenylcarbonate, methoxycarbonylphenylphenylcarbonate and ethoxycarbonylphenylphenylcarbonate Is preferably added. Among them, 2-chlorophenylphenyl carbonate and 2-methoxycarbonylphenylphenyl carbonate are preferable, and 2-methoxycarbonylphenylphenyl carbonate is particularly preferably used.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Aiko Hara 1-2-2 Uchisaiwaicho, Chiyoda-ku, Tokyo F-term in Teijin Chemicals Limited (reference) 4F071 AA50 AA81X AH14 BA01 BC03 BC07 4J029 AA09 AB01 AD01 AD10 AE05 HC03 KA02 KA03 5D029 KA07 KC17

Claims (5)

[Claims] 1. The monofunctional phenol content is 50 ppm.
An optical polycarbonate resin molding material comprising the following polycarbonate resin. 2. An optical polycarbonate molding material according to claim 1, wherein the polycarbonate resin has a viscosity average molecular weight of 10,000 to 22,000. 3. The polycarbonate resin molding material for optical use according to claim 1, wherein the monofunctional phenol is an alkyl-substituted or phenylalkyl-substituted phenol. 4. An optical disk substrate formed from the optical polycarbonate resin molding material according to claim 1. 5. A digital versatile resin formed from the optical polycarbonate resin molding material according to claim 1.
An optical disk substrate for a disk (DVD).