JP2002230829A - Optical disk substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical disk substrate nearly free from warpage and formed by using polycarbonate resin formed by copolymerization of specific aliphatic-aromatic monomers, having low water absorption, excellent fluidity and a small photoelastic modulus. SOLUTION: The optical disk substrate is formed by using the copolymer polycarbonate resin consisting of an aliphatic diol and a bivalent phenol having specific chemical structures in their molecular formulae.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an optical disk substrate formed of a specific aliphatic-aromatic copolymer polycarbonate resin. More particularly, the present invention relates to an optical disk substrate having low water absorption, excellent fluidity, and low warpage formed from a specific aliphatic-aromatic copolymer polycarbonate resin having a small photoelastic constant.

[0002]

2. Description of the Related Art Conventionally, 2,2-bis (4-hydroxyphenyl) propane (hereinafter referred to as bisphenol A).
Polycarbonate resins obtained by reacting a carbonate precursor with phenol are excellent in transparency, heat resistance, mechanical properties, and dimensional stability, and are therefore widely used as engineering plastics in many fields. Further, in recent years, utilization of the transparency as an optical material in the fields of optical disks, optical fibers, lenses, and the like has been developed, and in particular, it has been widely used as a material for substrates for information recording media in the field of optical disks.

However, the recent increase in the capacity of recorded information has made the requirements for the dimensional stability of optical discs for recording and reproducing information more and more severe, and the conventional polycarbonate resin obtained from bisphenol A has The demands are no longer being fully satisfied. In particular, an error caused by warpage of an optical disk caused by water absorption has become an important problem with precise control of dimensions of a molded product, and urgent improvement is required.

On the other hand, the polycarbonate resin obtained from bisphenol A has a disadvantage that the photoelastic constant is large due to the optical anisotropy of the benzene ring, and the birefringence of the molded product is large.
The birefringence can be improved to some extent depending on the molding conditions. That is, during the injection molding of the disk substrate, the resin is injected under low viscosity conditions to reduce the orientation of the resin, whereby a disk substrate with low optical anisotropy and small birefringence can be formed. Attempted.

However, there is a limit in reducing the birefringence of the disk only by the injection conditions, and a resin having a low photoelastic constant and a high fluidity is required by changing the structure of the polymer itself.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, and has good transparency, heat resistance and impact resistance, low water absorption and excellent fluidity. An object of the present invention is to provide an optical disk substrate having a small birefringence and a small warpage formed from a polycarbonate resin having a small photoelastic constant.

The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems. As a result, an optical disc substrate was formed using a copolymerized polycarbonate resin obtained by copolymerizing an aliphatic diol having a specific structure with a dihydric phenol. By doing so, it has been found that the above object can be achieved.

[0008]

According to the present invention, the following general formula [1]

[0009]

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And a structural unit represented by the following general formula [2]:

[0011]

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[In the above formula [2], R ¹ and R ² each independently represent a hydrogen atom, a halogen atom, a carbon atom of 1 to 1;
0 alkyl group, C1-C10 alkoxy group, C6-C20 cycloalkyl group, C6-C20 cycloalkoxy group, C6-C10 aryl group, C7-C20 aralkyl A aryloxy group having 6 to 10 carbon atoms and an aralkyloxy group having 7 to 20 carbon atoms, wherein m and n are each an integer of 0 to 4, and W is 5 carbon atoms.
~ 12 alicyclic hydrocarbon groups or

[0013]

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Preferably,

[0015]

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Wherein R ³ and R ⁴ are the same or different and each represent a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, and R ⁵ and R ⁶ are each independently a hydrogen atom or a carbon atom having 1 to 10 carbon atoms. 3 is an alkyl group, p is an integer of 4 to 7, R ⁷ and R ⁸ are each independently a hydrogen atom, a halogen atom or a carbon atom of 1;
To 3 alkyl groups. An optical disk substrate is provided which is formed from a copolymerized polycarbonate resin comprising the structural unit represented by the general formula [1] and having a molar fraction of 15 to 90 mol% of the structural unit represented by the general formula [1].

The aliphatic diol for deriving the structural unit represented by the above general formula [1] of the present invention may be a cis-form, a trans-form or a mixture of cis-trans-forms.
2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, and 1,4-cyclohexanedimethanol are exemplified. Among them, 1,4-cyclohexanedimethanol is preferred. These may be used alone or in combination of two or more.

Examples of the dihydric phenol for deriving the structural unit represented by the general formula [2] include, for example, 4,
4'-dihydroxybiphenyl, bis (4-hydroxyphenyl) methane, 1,1-bis (4-hydroxyphenyl) ethane, 1,1-bis (4-hydroxyphenyl) -1-phenylethane, 2,2-bis (4-hydroxyphenyl) propane, 2,2-bis (4-hydroxy-3-methylphenyl) propane, 1,1-bis (4
-Hydroxyphenyl) -3,3,5-trimethylcyclohexane, 2,2-bis (4-hydroxy-3,3 ′
-Biphenyl) propane, 2,2-bis (4-hydroxy-3-isopropylphenyl) propane, 2,2-bis (3-t-butyl-4-hydroxyphenyl) propane, 2,2-bis (4-hydroxy Phenyl) butane,
2,2-bis (4-hydroxyphenyl) octane,
2,2-bis (3-bromo-4-hydroxyphenyl)
Propane, 2,2-bis (3,5-dibromo-4-hydroxyphenyl) propane, 2,2-bis (3,5-dichloro-4-hydroxyphenyl) propane, 2,2-
Bis (3,5-dimethyl-4-hydroxyphenyl) propane, 2,2-bis (3-cyclohexyl-4-hydroxyphenyl) propane, 1,1-bis (3-cyclohexyl-4-hydroxyphenyl) cyclohexane,
Bis (4-hydroxyphenyl) diphenylmethane,
9,9-bis (4-hydroxyphenyl) fluorene,
9,9-bis (4-hydroxy-3-methylphenyl)
Fluorene, 1,1-bis (4-hydroxyphenyl)
Cyclohexane, 1,1-bis (4-hydroxyphenyl) cyclopentane, 4,4′-dihydroxydiphenyl ether, 4,4′-dihydroxy-3,3′-dimethyldiphenyl ether, 4,4′- Sulfonyldiphenol, 4,4'-dihydroxydiphenylsulfoxide, 4,4'-dihydroxydiphenylsulfide,
2,2′-dimethyl-4,4′-sulfonyldiphenol, 4,4′-dihydroxy-3,3′-dimethyldiphenylsulfoxide, 4,4′-dihydroxy-3,
3'-dimethyldiphenyl sulfide, 2,2'-diphenyl-4,4'-sulfonyldiphenol, 4,4 '
-Dihydroxy-3,3'-diphenyldiphenylsulfoxide, 4,4'-dihydroxy-3,3'-diphenyldiphenylsulfide, 1,3-bis {2- (4-
(Hydroxyphenyl) propyl} benzene, 1,4-bis {2- (4-hydroxyphenyl) propyl} benzene, 1,4-bis (4-hydroxyphenyl) cyclohexane, 1,3-bis (4-hydroxyphenyl) cyclohexane , 4,8-bis (4-hydroxyphenyl)
Tricyclo [5.2.1.0 ^2,6 ] decane, 4,4′-
(1,3-adamantandiyl) diphenol, 1,3
-Bis (4-hydroxyphenyl) -5,7-dimethyladamantane.

Among them, 1,1-bis (4-hydroxyphenyl) -1-phenylethane and 2,2-bis (4-
(Hydroxyphenyl) propane, 2,2-bis (4-hydroxy-3-methylphenyl) propane, 2,2-bis (3,5-dibromo-4-hydroxyphenyl) propane, 1,1-bis (4-hydroxy Phenyl) cyclohexane, 1,1-bis (4-hydroxyphenyl)-
3,3,5-trimethylcyclohexane, 4,4'-sulfonyldiphenol, 2,2'-dimethyl-4,4 '
-Sulfonyldiphenol, 9,9-bis (4-hydroxy-3-methylphenyl) fluorene, 1,3-bis {2- (4-hydroxyphenyl) propyl} benzene, 1,4-bis {2- (4 -Hydroxyphenyl) propyl} benzene is preferred, especially 2,2-bis (4-
Hydroxyphenyl) propane (BPA), 1,1-bis (4-hydroxyphenyl) cyclohexane,
4'-Sulfonyldiphenol, 9,9-bis (4-hydroxy-3-methylphenyl) fluorene is preferred. These may be used alone or in combination of two or more.

The aliphatic-aromatic copolymerized polycarbonate resin has a total molar fraction of all constituent units of 10%.
When it is 0 mol%, the molar fraction of the structural unit represented by the general formula [1] is 15 to 90 mol%, and
5 mol% is preferred. If it exceeds 90 mol%, the heat resistance may be reduced, and if it is less than 15 mol%, the fluidity of the polymer may be reduced, which is not preferable as a material for an optical disk substrate.

The polycarbonate resin of the present invention is used as an optical disk substrate material by dissolving 0.7 g of the resin in 100 ml of methylene chloride and having a specific viscosity of 0.2 at 20 ° C.
Those having a range of 1 to 0.7 are preferable, and those having a range of 0.2 to 0.6 are more preferable. A polycarbonate resin having a specific viscosity in such a range is preferable because an optical disk substrate having good melt fluidity, excellent moldability, and optically satisfactory strength can be obtained.

The flowability (Q value) of the polycarbonate resin of the present invention is preferably 25 × 10 ⁻³ cm ³ / s or more, more preferably 30 to 200 × 10 ⁻³ cm ³ / s.
Most preferably, it is 35 to 200 × 10 ⁻³ cm ³ / s.

The water absorption of the polycarbonate resin of the present invention is preferably 0.20% by weight or less, more preferably 0.18% by weight or less. If the content exceeds 0.20% by weight, the optical disk having the metal film formed on the surface of the optical disk substrate may be liable to warp due to water absorption. Particularly preferred water absorption is 0.15% by weight or less.

The polycarbonate resin of the present invention has a photoelastic constant of preferably 80 × 10 ⁻⁸ cm ² / N or less, more preferably 76 × 10 ⁻⁸ cm ² / N or less. When the photoelastic constant has a value within this range, the birefringence becomes small, and it is advantageously used particularly in high-density optical disks.

In order to produce the aliphatic-aromatic polycarbonate resin copolymer of the present invention, the aliphatic diol and the dihydric phenol are reacted with phosgene in the presence of an acid binder such as pyridine ( (Solution method) or a method in which a transesterification reaction is carried out under melting conditions using bisaryl carbonate (melting method).

Among them, in the solution method, pyridine, quinoline, dimethylaniline and the like are preferred as the acid binder, and pyridine is particularly preferred. These may be used alone or diluted with an organic solvent. As the organic solvent, hydrocarbons such as benzene, toluene and xylene, methylene chloride, chloroform, dichloroethane, chlorobenzene and halogenated hydrocarbons such as dichlorobenzene are used, and in particular, methylene chloride, chloroform, dichloroethane, chlorobenzene,
Halogenated hydrocarbons such as dichlorobenzene are preferred,
In particular, methylene chloride is most preferred. The amount of the acid binder to be used is generally 2 to 100 molar equivalents, preferably 2 to 50 molar equivalents, relative to phosgene. The reaction temperature is preferably from 0 to 40 ° C. The reaction time is usually several minutes to several days, preferably 10 minutes to 5 hours.

Further, monofunctional phenols can be used as a terminal stopper. Monofunctional phenols are commonly used as molecular terminators for molecular weight control, and the resulting polycarbonate resins are capped by groups based on monofunctional phenols, so that Excellent heat stability. Specific examples of such monofunctional phenols include, for example, phenol,
p-tert-butylphenol, p-cumylphenol and isooctylphenol. Also,
As other monofunctional phenols, phenols or benzoic acid chlorides having a long-chain alkyl group or aliphatic polyester group as a substituent, or long-chain alkyl carboxylic acid chlorides can be used.

These terminal stoppers are desirably introduced at least 5 mol%, preferably at least 10 mol%, based on all terminals of the obtained polycarbonate resin, and the terminal stopper is used alone or You may mix and use 2 or more types.

The melting method is carried out by mixing an aliphatic or aromatic diol with a carbonate ester while heating in the presence of an inert gas to distill off the alcohol or phenol formed. The reaction temperature depends on the boiling point of the alcohol or phenol to be produced, etc.
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 1330 to 13.3 Pa to facilitate the distillation of alcohol or phenol produced. The reaction time is usually about 1 to 4 hours.

Examples of the carbonate ester include an optionally substituted ester such as an aryl group having 6 to 12 carbon atoms, an aralkyl group or an alkyl group having 1 to 4 carbon atoms. Specifically, diphenyl carbonate, bis (chlorophenyl) carbonate, m-cresyl carbonate, dinaphthyl carbonate, bis (diphenyl)
Examples thereof include carbonate, dimethyl carbonate, diethyl carbonate, and dibutyl carbonate. Among them, diphenyl carbonate is preferable.

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 salts and potassium salts 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 , Organic acid salts of alkali metals and alkaline earth metals, zinc compounds, boron compounds, aluminum compounds, silicon compounds, germanium compounds, organotin compounds, lead compounds, osmium compounds, antimony compounds, manga 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 these polymerization catalysts to be used is preferably 1 × 10 ⁻⁹ to 1 ×, based on 1 mol of the starting dihydric phenol.
It is selected in the range of 10 ⁻³ equivalents, more preferably 1 × 10 ^{−8 to} 5 × 10 ⁻⁴ equivalents. Further, a molecular weight regulator, an antioxidant and the like may be added as necessary.

A catalyst deactivator can be added to the copolymerized polycarbonate resin obtained in the present invention. As the catalyst deactivator used in the present invention, known catalyst deactivators are effectively used. Among them, ammonium salts of sulfonic acid,
Phosphonium salts are preferred, and the above salts of dodecylbenzenesulfonic acid such as tetrabutylphosphonium dodecylbenzenesulfonate and the above salts of paratoluenesulfonic acid such as tetrabutylammonium paratoluenesulfonate are more preferred. As sulfonic acid esters, methyl benzenesulfonate, ethyl benzenesulfonate, butylbenzenesulfonate, octylbenzenesulfonate, phenylbenzenesulfonate, methyl paratoluenesulfonate, ethyl paratoluenesulfonate, butylparatoluenesulfonate, para Octyl toluenesulfonate, phenyl paratoluenesulfonate and the like are preferably used, and among them, tetrabutylphosphonium dodecylbenzenesulfonate is most preferably used.

The amount of the catalyst deactivator used is 0.5 to 50 mol, preferably 0.5 to 50 mol, per 1 mol of the polymerization catalyst selected from alkali metal compounds and / or alkaline earth metal compounds. It can be used at a ratio of 10 mol, more preferably at a ratio of 0.8 to 5 mol.

The optical disk substrate of the present invention can be obtained by molding the copolymerized polycarbonate resin by any method such as injection molding, compression molding, extrusion molding, etc. The optical disk substrate obtained by the injection molding method is excellent in productivity and suitable.

The optical disc substrate of the present invention generally comprises a polycarbonate resin having a resin temperature of 250 to 380 ° C.
It is obtained by injection molding at a mold temperature of 60 to 130 ° C., or obtained by laminating them.

A phosphorus heat stabilizer can be added to the copolymerized polycarbonate resin of the present invention, if necessary.
As the phosphorus-based heat stabilizer, phosphites and phosphates are preferably used. As the phosphite,
For example, triphenyl phosphite, trisnonylphenyl phosphite, tris (2,4-di-tert-butylphenyl) phosphite, tridecyl phosphite,
Trioctyl phosphite, trioctadecyl phosphite, didecyl monophenyl phosphite, dioctyl monophenyl phosphite, diisopropyl monophenyl phosphite, monobutyl diphenyl phosphite,
Monodecyl diphenyl phosphite, monooctyl diphenyl phosphite, bis (2,6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphite, 2,2-methylene bis (4,6-di-te
rt-butylphenyl) octyl phosphite, bis (nonylphenyl) pentaerythritol diphosphite, bis (2,4-di-tert-butylphenyl) pentaerythritol diphosphite, tetrakis (2
Examples thereof include triesters, diesters and monoesters of phosphorous acid such as 4-di-tert-butylphenyl) -4,4-diphenylenephosphonite. Of these, trisnonylphenyl phosphite, distearylpentaerythritol diphosphite, tris (2,4-di-t
(tert-butylphenyl) phosphite is preferred.

On the other hand, examples of the phosphoric acid ester used as a heat stabilizer include tributyl phosphate, trimethyl phosphate, tricresyl phosphate, triphenyl phosphate, trichlorophenyl phosphate, triethyl phosphate, diphenylcresyl phosphate, and diphenylmonoorthoxenyl. Phosphate, tributoxyethyl phosphate, dibutyl phosphate, dioctyl phosphate, diisopropyl phosphate and the like can be mentioned, and among them, triphenyl phosphate and trimethyl phosphate are preferable.

The phosphorus heat stabilizers may be used alone or in combination of two or more. The phosphorus-based heat stabilizer is 0.0% based on the copolymerized polycarbonate resin.
It is suitable to use in the range of 001 to 0.05% by weight.

To the copolymerized polycarbonate resin obtained in the present invention, an antioxidant generally known for the purpose of preventing oxidation can be added. Examples thereof include phenolic antioxidants, and specifically, for example, triethylene glycol-bis (3- (3-tert-butyl-
5-methyl-4-hydroxyphenyl) propionate), 1,6-hexanediol-bis (3- (3,5
-Di-tert-butyl-4-hydroxyphenyl) propionate, pentaerythritol-tetrakis (3
-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate), octadecyl-3- (3,
5-di-tert-butyl-4-hydroxyphenyl)
Propionate, 1,3,5-trimethyl-2,4,6
-Tris (3,5-di-tert-4-hydroxybenzyl) benzene, N, N-hexamethylenebis (3,5
-Di-tert-butyl-4-hydroxyhydrocinnamide), 3,5-di-tert-butyl-4-hydroxybenzylphosphonate diethyl ester, tris (3,5-di-tert-butyl-4-hydroxybenzyl) Isocyanurate, 3,9-bis {1,1-dimethyl-2- [β- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy] ethyl} -2,4,8,10- Tetraoxaspiro (5
5) Undecane and the like. The preferable range of the addition amount of these antioxidants is 0.0001 to 0.05% by weight based on the copolymerized polycarbonate resin.

Further, a higher fatty acid ester of a polyhydric alcohol can be added to the copolymerized polycarbonate resin obtained in the present invention, if necessary. By adding this higher fatty acid ester, the thermal stability of the copolymerized polycarbonate resin is improved, the fluidity of the resin at the time of molding is improved, and the releasability of the substrate from the mold after molding is improved, thereby improving the release. Deformation of the disk substrate due to defective mold can be prevented.
The higher fatty acid ester is preferably a partial ester or a whole ester of a polyhydric alcohol having 2 to 5 carbon atoms and a saturated fatty acid having 10 to 30 carbon atoms. Examples of the polyhydric alcohol include glycols, glycerol and pentaerythritol.

The higher aliphatic acid ester is added in an amount of 0.005 to 2% by weight, preferably 0.02 to 0.1% by weight, based on the weight of the copolymerized polycarbonate resin. is there. The addition amount in such a range is preferable because the effects described above are obtained and the surface of the mold is hardly stained.

Additives such as a light stabilizer, a colorant, an antistatic agent and a lubricant can be further added to the copolymerized polycarbonate resin obtained in the present invention as long as the transparency is not impaired. Further, other polycarbonate resins and thermoplastic resins can be added in small proportions within a range not to impair the object of the present invention.

The optical disk of the present invention covers a range from a compact disk for audio (recording density of about 650 MB per disk having a diameter of 12 cm) to a high-density disk. For example, 4.7 GB capacity recently
DVD-ROM, recordable / reproducible DVD-R, DVD
-A capacity of 4.7 GB is being realized also in RW and DVD-RAM. For a MO disk, 5.2 GB on both sides at 5.25 "size, and 1.3 GB on one side at 3.5"
Although the optical information recording medium of type B is on the market, a high-density optical recording medium having a diameter of about 6.5 GB or more, particularly 10 GB or more on one side in terms of a disk having a diameter of 12 cm corresponding to digital high-definition broadcasting is demanded. The optical disk substrate of the present invention has characteristics that can be sufficiently applied to these substrates.

The optical disk substrate of the present invention can be obtained by forming a metal thin film on at least one surface thereof. This metal includes aluminum, Tb, F
e, Co, Gd, SiN, ZnS-SiO 2, GeSb
There are Te, ZnS, and aluminum alloys, and aluminum is suitable. The thin film can be formed by means such as sputtering and vapor deposition. Means for forming these metal thin films can be performed by a method known per se.

[0045]

The present invention will be further described with reference to the following examples. Parts and% in the examples are parts by weight and% by weight. In addition, the measurement of each item was performed by the following method. (1) Specific viscosity Using methylene chloride as a solvent, polycarbonate resin 0.1.
It was measured at a concentration of 7 g / 100 ml. The measurement temperature was set to 20 ° C. (2) Q value Using a flow tester CFT-500C manufactured by Shimadzu Corporation, the volume flowing out of a 1.0 mm diameter nozzle from a 1.0 mm diameter nozzle at a temperature of 240 ° C. under a load of 100 kg was measured using a cylinder having a diameter of 10 mm and a length of 20 mm. did. (3) Photoelastic constant The photoelastic constant was measured using a 100 μm thick cast film with a photoelasticity measuring device PA-150 manufactured by Riken Kiki Co., Ltd. (4) Water absorption The water absorption after immersion in water at 23 ° C. for 24 hours was measured according to ASTM D-0570.

Example 1 43.2 parts by weight of 1,4-cyclohexanedimethanol (hereinafter referred to as "CHDM")
Bisphenol-A (hereinafter referred to as "BPA") 68.4
Parts by weight, 134.96 parts by weight of diphenyl carbonate (hereinafter, referred to as "DPC") and 0.18 parts by weight of tetramethylammonium hydroxide (hereinafter, referred to as "TMAH").
8 parts by weight of sodium hydroxide and 8 × 10 ^-4 parts by weight of sodium hydroxide were charged into a reaction vessel equipped with a stirrer, a still and a depressurizing apparatus, and after displacing with nitrogen, dissolved at 140 ° C. After stirring for 30 minutes, the internal temperature was gradually raised to 180 ° C. and the pressure was gradually reduced to 1.3 × 10 ⁴ P
The reaction was carried out at a for 30 minutes, and the formed phenol was distilled off. Then, the temperature was kept rising while maintaining the same pressure.
Phenol was distilled off for 0 minute, at 200 ° C. for 40 minutes, at 220 ° C. for 30 minutes, and further at 240 ° C. for 30 minutes to react. Thereafter, the pressure was slowly reduced to 1.3 × 10 ² Pa or less. The mixture was reacted under reduced pressure at 240 ° C. for 4 hours under stirring to obtain a copolymerized polycarbonate resin. In this resin,
To 100 parts of the resin, tris (2,4-di-ter
0.003 parts of t-butylphenyl) phosphite, 0.005 parts of trimethyl phosphate and 0.0045 parts of stearic acid monoglyceride were added. Next, a vent-type twin screw extruder [KT made by Kobe Steel Ltd.]
X-46], melt-kneaded while degassing at a cylinder temperature of 240 ° C, and pelletized. The pellets were prepared using M35BD-DM manufactured by Meiki Seisakusho Co., Ltd. at a resin temperature of 240 ° C., a mold temperature of 70 ° C., a cooling time of 15 seconds, and an injection speed of 150 mm / sec (filling time of 0.43 sec).
A disk substrate having a thickness of 0 mmφ and a thickness of 1.2 mmt was injection molded. Further, aluminum was evaporated on the disk substrate to obtain a disk. The warpage of this disk due to water absorption
It was much smaller than the disk obtained in Comparative Example 1. The evaluation results are shown in Table 1.

Example 2 25.9 parts by weight of CHDM, B
95.8 parts by weight of PA, 134.96 parts by weight of DPC and 0.18 part by weight of TMAH, sodium hydroxide 8 × 10
^A disc was obtained in the same manner as in Example 1, except that ^-4 parts by weight was used. The warpage of this disk due to water absorption was much smaller than that of the disk obtained in Comparative Example 1. In addition, the evaluation result was shown in Table 1.

Example 3 60.48 parts by weight of CHDM
9,9-bis (4-hydroxy-3-methylphenyl)
68.04 parts by weight of fluorene (hereinafter referred to as “BCF”), 134.96 parts by weight of DPC and 0.1% of TMAH
A disk was obtained in the same manner as in Example 1, except that 8 parts by weight and 8 × 10 ⁻⁴ parts by weight of sodium hydroxide were used. The warpage of this disk due to water absorption was much smaller than that of the disk obtained in Comparative Example 1. In addition, the evaluation result was shown in Table 1.

Example 4 25.3 parts by weight of CHDM, B
17.2 parts by weight of PA and 0.89 parts by weight of p-tert-butylphenol were charged into a reactor equipped with a thermometer and a stirrer,
After purging with nitrogen, the pyridine 20 is dried well in advance.
3 parts by weight and 563 parts by weight of methylene chloride were added and dissolved.
At 25 ° C., 28.6 parts by weight of phosgene was blown in with stirring over 100 minutes. After the injection of phosgene, the reaction was completed by stirring for about 10 minutes. After the reaction is completed, the product is diluted with methylene chloride, pyridine is neutralized and removed with hydrochloric acid, and then repeatedly washed with water until the conductivity becomes almost the same as ion-exchanged water.
Thereafter, the methylene chloride was evaporated to obtain a colorless powder.
This powder was pelletized by the same operation as in Example 1, and then a disk substrate was injection-molded. Further, aluminum was deposited on the disk substrate to obtain a disk. The warpage of this disk due to water absorption was much smaller than that of the disk obtained in Comparative Example 1. In addition, the evaluation result was shown in Table 1.

Example 5 25.3 parts by weight of CHDM
20.2 parts by weight of 1,1-bis (4-hydroxyphenyl) cyclohexane (hereinafter abbreviated as “BPZ”), p-te
0.89 parts by weight of rt-butylphenol, phosgene 2
8.6 parts by weight, pyridine 203 parts by weight, methylene chloride 5
Except that 64 parts by weight were used, the same operation as in Example 3 was performed to obtain a polycarbonate powder. This powder was pelletized by the same operation as in Example 1, and then a disk substrate was injection-molded. Further, aluminum was deposited on the disk substrate to obtain a disk. The warpage of the disk due to water absorption was smaller than that of the disk obtained in Comparative Example 1.
It was much smaller. In addition, the evaluation result was shown in Table 1.

Example 6 8.4 parts by weight of CHDM, BP
A8.0 parts by weight, 5.9 parts by weight of 4,4′-sulfonyldiphenol (hereinafter abbreviated as “BPS”), p-tert
-0.087 parts by weight of butylphenol, phosgene 13.
A polycarbonate powder was obtained in the same manner as in Example 3, except that 9 parts by weight, 95 parts by weight of pyridine, and 263 parts by weight of methylene chloride were used. This powder was used in Example 1
A pellet was formed by performing the same operation as described above, and then a disk substrate was injection-molded. Further, aluminum was deposited on the disk substrate to obtain a disk. The warpage of this disk due to water absorption was much smaller than that of the disk obtained in Comparative Example 1. In addition, the evaluation result was shown in Table 1.

Comparative Example 1 A bisphenol-A (BPA) type polycarbonate resin powder obtained by an interfacial polymerization method was pelletized by the same operation as in Example 1, and then a disk substrate was injection-molded. Aluminum was deposited on the disk substrate to obtain a disk. In addition, the evaluation result was shown in Table 1.

[0053]

[Table 1]

[0054]

The aliphatic-aromatic copolymerized polycarbonate resin of the present invention has low water absorption, excellent fluidity, and a small photoelastic constant. It is suitably used as a material for a high-density optical disk substrate, and the industrial effects achieved are outstanding.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Yoshihiko Imanaka 1-2-2 Uchisaiwai-cho, Chiyoda-ku, Tokyo Teijin Chemicals Limited F-term (reference) 4J029 AA09 AE05 BB10A BB12A BB12C BB13A BB13B BB16A BB18 BD06A BD07A BD09A BD09B BD09C BF14A BF14B BG08X BH02 DB07 DB11 DB13 HC01 HC04A HC05A HC05B 5D029 KA07 KA08 KC01 MA18

Claims (4)

[Claims] [Claim 1] The following general formula [1] And a structural unit represented by the following general formula [2]: [In the above formula [2], R ¹ and R ² are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, and a cycloalkyl having 6 to 20 carbon atoms. Group, a cycloalkoxy group having 6 to 20 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, an aryloxy group having 6 to 10 carbon atoms, an aralkyloxy group having 7 to 20 carbon atoms, Where m and n
Is an integer of 0 to 4, respectively, and W is an alicyclic hydrocarbon group having 5 to 12 carbon atoms or Wherein R ³ and R ⁴ are the same or different and represent a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, and R ⁵ and R ⁶
Are each independently a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, p is an integer of 4 to ^7, and R ⁷ and R ⁸ are each independently a hydrogen atom, a halogen atom or an alkyl group having 1 to 3 carbon atoms. is there. An optical disk substrate formed of a copolymerized polycarbonate resin comprising the structural unit represented by the general formula [1] and having a molar fraction of 15 to 90 mol% of the structural unit represented by the general formula [1]. 2. The optical disc substrate according to claim 1, wherein the general formula [1] is a structural unit derived from 1,4-cyclohexanedimethanol. 3. The compound of the general formula [2] is 2,2-bis (4-
Hydroxyphenyl) propane, 1,1-bis (4-hydroxyphenyl) cyclohexane, 4,4′-sulfonyldiphenol and 9,9-bis (4-hydroxy-
2. The optical disc substrate according to claim 1, wherein the optical disc substrate is a structural unit derived from at least one dihydric phenol selected from the group consisting of (3-methylphenyl) fluorene. 4. An optical disk having a metal thin film formed on at least one surface of the optical disk substrate according to claim 1.