JPH01101327A - Aromatic polycarbonate terpolymer - Google Patents

Abstract

PURPOSE:To obtain the titled copolymer, having specific glass transition temperature and photoelasticity constant, capable of remarkably improving CN ratio by reducing values of birefringence with excellent durability and useful as optical disks for recording information. CONSTITUTION:The aimed copolymer, obtained by bonding (A) 1-99mol.% at least two or more of 2,2-bis-(4-hydroxy-3-tertiary butyl)-2-phenylethane, 1,1,- bis-(4-hydroxy-3-tertiary butylphenyl)cyclohexane, etc., to (B) 1-30mol.% dihydric phenol, such as 2,2-bis-(4-hydroxy-3-methylphenyl)propane, through carbonate bonds and having >=130 deg.C glass transition temperature and <=60 Brewsters photoelasticity constant. The total amount of the components (A) and (B) is 100mol.%.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a polycarbonate material used in optical information recording discs that record signals using laser beams or read signals recorded by reflection or transmission of laser beams. It relates to original copolymers and is mainly used for optical discs.

(Prior art) DRAW (direct read) is a method in which a spot beam of a laser beam is applied to a disk, and signals are recorded in minute pits on the disk, or signals recorded by such pits are read out by detecting the amount of reflected or transmitted light of the laser beam.・After Light), Erasab
le-DRAW (erasable, direct read)
The after-write (after-write) type optical information recording/reproducing method can significantly increase the recording density, and is especially suitable for erasable
- With the DRAW type, it is also possible to erase and write records,
In addition, since the images and sound quality reproduced from them have excellent characteristics, it is expected that they will be widely put to practical use in recording and reproducing images and sound quality, recording and reproducing large amounts of information, etc.

The disks used in this recording/reproducing system are not only required to be transparent so that laser beams can pass through the disk body, but also to have optical homogeneity to reduce reading errors. Birefringence occurs when the laser beam passes through the disk body, mainly due to thermal stress generated during the cooling and flow process of the resin during disk body formation, residual stress due to molecular orientation and volume change near the glass transition point.

This large optical non-uniformity caused by birefringence is a fatal defect for optical discs.

(Problems to be Solved by the Invention) Birefringence, which is mainly caused by the thermal stress bimolecular orientation and residual stress generated during the cooling and flow process of the resin during disk molding, can be reduced by selecting the forming conditions. , although the birefringence of the resulting disc can be made considerably smaller,
It largely depends on the inherent birefringence of the molding resin itself, that is, the photoelastic constant.

(Means for solving the problem) Birefringence can be expressed by the following equation (1) as a product of a photoelastic constant and a residual stress.

nl-n2=C(al-a2) (1)
nl-n2: Birefringence σ1-σ2: Residual stress C: Photoelastic constant It is clear that if the photoelastic constant in equation (1) is made smaller, the birefringence of the disc obtained will be smaller even if the molding conditions are the same. Therefore, the inventors discovered that component (I) and component (II)
The present invention was based on the discovery that a resin with a small photoelastic constant can be obtained without impairing the mechanical properties of aromatic polycarbonate by copolymerizing a composition selected from dihydric phenols with carbonate bonds. .

(Structure of the invention) Component (I) is 1 to 99 mol%, other component (II) is 1
~30 mol% and the total of components I and II is 100 mol%
is an aromatic polycarbonate copolymer obtained by carbonate bonding of at least two or more of the following components and component II arbitrarily selected from one of the following dihydric phenols, the glass transition temperature of which is 1306C or higher and a photoelastic constant of 60 Brewsters (Bre
wsters, 10-12 m2/N) or less.

I: 2,2-bis-(4-hydroxy-3-tert-butyl)-2-phenylethane (A
)4.4'-dihydroxy-2,2,2-triphenylethane (B) 1.1. Bis-(4-hydroxy-3-tert-butylphenyl)cyclohexane (C)II: 1.
1-bis-(3,5-dimethyl-4-hydroxyphenyl)-bara-diisopropylbenzene (D)2.2-
Bis-(3,5-dimethyl-4-hydroxyphenyl)
Propane (E)2.2-bis-
(4-hydroxy-3-methylphenyl)propane
(F)2.2. Bis-(4-hydroxy-3,isopropylphenyl)propane
(G) (Effect of the invention) In this aromatic polycarbonate copolymer, the component (I
The content of the structural unit I) is preferably 3 to 30 mol%.

When the content of this structural unit exceeds 30 mol %, the long-term thermal stability of the resulting aromatic polycarbonate copolymer decreases, causing discoloration and deterioration due to heat. In addition, if it is less than 3 mol%, the component (I
No reduction in the photoelastic constant was observed due to the introduction of I).

The copolymer of the present invention has a viscosity average molecular weight of 13,000 to 50,0 in terms of bisphenol A-polycarbonate.
00 is preferred. If it is less than 13,000, the copolymer becomes brittle, and if it exceeds 50,000, the melt fluidity will be poor and the moldability will be poor. There are the following two methods for producing the polycarbonate copolymer of the present invention.

■Transesterification method For example, 2,2-bis-(4-hydroxy-3-tert-butyl)-2-phenylethane (A) and 1,1-bis-(4-hydroxy-3-tert-butyl phenyl ) Addition of a conventional carbonation catalyst to a slightly stoichiometrically equivalent excess of diphenyl carbonate to a mixture of cyclohexane (C) and 2,2-bis-(4-hydroxy-3-methylphenyl)propane (F) In the presence of about 16
The reaction was carried out for about 30 minutes at a temperature of 0 to 180°C, under normal pressure, and with an inert gas introduced, and the pressure was gradually reduced over a period of 2 hours until the final reaction temperature was increased to 10 Torr at a temperature of about 180 to 220°C.
r, the precondensation ends at 220'C. After that, 10To
rr, 30 minutes at 270°C, 5 Torr, 20 minutes at 270°C
0.5 Torr or less, preferably 0.5 Torr or less.
3 Torr~0. 1. at 270°C under a vacuum of ITorr.
After 5 hours to 2.0 hours, the condensation is allowed to proceed. In addition, as carbonation catalysts for carbonate bonding, alkali metal and alkaline earth metal catalysts such as lithium-based catalysts, potassium-based catalysts, sodium-based catalysts, calcium-based catalysts, and tin-based catalysts are suitable. Examples include lithium, lithium carbonate, potassium borohydride, potassium hydrogen phosphate, sodium hydroxide, sodium borohydride, calcium hydride, dibutyltin oxide, and stannous oxide. Among these, it is preferable to use a potassium-based catalyst.

■Phosgene method Three-loaf flask with stirrer, thermometer, gas inlet pipe,
Attach an exhaust pipe and add, for example, 2,2-bis-(4-hydroxy-3-tert-butyl)-2-phenylethane (A) and 1,1-bis-(4-hydroxy-3-tert-butyl). butylphenyl)cyclohexane (C) and 2,2
A pyridine solution of a mixture of -bis-(4-hydroxy-3-methylphenyl)propane (F) is added, and phosgene gas is introduced while stirring the mixture vigorously. Since phosgene is extremely poisonous, it must be operated in a strong fume hood. Additionally, a unit is installed at the exhaust end to decompose and detoxify excess phosgene with a 10% sodium hydroxide aqueous solution. Phosgene is introduced into the flask through an empty air washing bottle, an air washing bottle containing paraffin (count the number of ponds), and an empty air washing bottle. The glass introduction tube should be inserted above the stirrer, and the tip should be widened into a funnel shape to prevent it from becoming clogged by precipitated pyridine salt. As gas is introduced, pyridine hydrochloride precipitates and the contents become cloudy. Water cooling is performed so that the reaction temperature is 30°C or less. It becomes viscous as the condensation progresses.

Phosgene is passed through the mixture until the yellow color of the phosgene-hydrogen chloride complex no longer disappears. After the reaction is completed, methanol is added to precipitate the polymer, which is then filtered and dried.

The polycarbonate produced is methylene chloride, pyridine,
Because it dissolves in chloroform, tetrahydrofuran, etc.
These solutions are purified by reprecipitation with methanol. The polycarbonate copolymer thus obtained is useful for DRAW and Erasabie-DRAW type optical information recording discs that record signals using laser beams or read signals recorded by reflection or transmission of laser beams. be. EXAMPLES The present invention will be described below with reference to Examples, but the present invention is not limited to these Examples.

In addition, the viscosity average molecular weight shown in the following examples is determined using a methylene chloride solution of bisphenol A polycarbonate at 20°C and obtained as a relational expression between the intrinsic viscosity [r1] and the molecular weight Mv [r11= 1.11Kari0-4Mv0.82 [E, Mii
11er&O, Bayer; USP2,999,844
(1961)] is the molecular weight in terms of bisphenol A polycarbonate calculated from the intrinsic viscosity using the formula.

(Example) Example 1 207 parts by weight (50 m
o1%) and 1,1-bis-(4-hydroxy-3-tert-butylphenyl)cyclohexane (C) 116 parts by weight (30mol1%) and 2,2-bis-(4-hydroxy,3-methylphenyl) ) Propane (F) 62 parts by weight (
20 mo 1%) and 264 parts by weight of diphenyl carbonate were placed in a 31 molar flask, and after repeating degassing and N2 purge five times, they were melted in a silicon bath at 160° C. while nitrogen was introduced. Once melted, add a solution of potassium borohydride, which is a carbonation catalyst, dissolved in phenol (10-3 mo based on the total amount of bisphenol charged).
1% amount) was added, and the mixture was stirred and incubated at 160°C under N2 for 30 minutes. Next, the pressure was reduced to IQQTorr at the same temperature, and 30
Minutes.

After stirring, the pressure was further reduced to 5 Q Torr at the same temperature, and the mixture was reacted for 60 minutes. Next, the temperature was gradually raised to 220° C. and the reaction was carried out for 60 minutes, and 80% of the theoretical amount of phenol was distilled out through the reaction up to this point.

Thereafter, the pressure was reduced to 1 Q Torr at the same temperature, and the reaction was carried out for 30 minutes.The temperature was gradually raised to 270°C, and the reaction was carried out for 30 minutes.

Further, at the same temperature, the pressure was reduced to 5 Torr and the reaction was carried out for 30 minutes.
Almost the entire theoretical amount of phenol was distilled off to complete the precondensation. Next, the wires were recombined at the same temperature for 2 hours at 0.1 to Q and 3 Torr. After the product polymer was taken out and cooled under nitrogen, the solution viscosity was measured at 20° C. using dichloromethane as a solvent.

Viscosity average molecular weight Mv calculated from this value = 18,0
It was 00. Also, DSC (Differential Scanning Calorimeter; Perkin-Elme
r2C type), the glass transition point was found to be Tg=140°C. Furthermore, when the photoelastic constant is measured, C=28
Brewsters (10-12m)
2/N). The equipment used for the measurement was a DSC; Differential Scanning Calorimeter Perkin-E1mer 2C type, and the photoelastic constant was measured using a self-made one. ) was added with different magnitudes of tensile stress in the length direction, each value was substituted into the above equation (1), and the photoelastic constant was determined from the slope. Incidentally 2,2
- The photoelastic constant of the polycarbonate of vin(4-hydroxyphenyl)propane is C=82 Brewster's (B
Example 2 A three-necked flask is equipped with a stirrer, a thermometer, a gas inlet pipe, and an exhaust pipe. 2, in a 10% by weight aqueous solution of sodium hydroxide.
2. Bis-(4-hydroxy-3-tert-butyl)
-2-phenylethane (A) 207 t i parts (50
mo1%) and 1,1-bis-(4-hydroxy-3-tert-butylphenyl)cyclohexane (C) 116
ft parts (30 mo 1%) and 62 parts by weight (20 mo 1%) of 2,2-bis-(4-hydroxy-3-methylphenyl)propane (F) were dissolved, dichloromethane was added,
Phosgene gas was introduced while stirring the mixture vigorously.

Phosgene was introduced from the cylinder into the flask through an empty air wash bottle, a water filled air wash bottle, and an empty air wash bottle. The reaction temperature during introduction of phosgene gas was water-cooled to be 25° C. or lower. As the condensation progresses, the solution becomes viscous. Furthermore, after the reaction was completed, the reaction solution was poured into methanol, filtered, and washed with water repeatedly. Further, the produced polycarbonate was purified by reprecipitation with methanol from a dichloromethane solution. After purification and thorough drying, the solution viscosity was measured at 20°C using dichloromethane as a solvent. The viscosity average molecular weight calculated from this value was 19,000. Furthermore, when the same measurements as in Example 1 were performed, it was found that the glass transition point and photoelastic constant were the same as in Example 1.

Example 3 166 parts by weight of 2.2-bis-(4-hydroxy-3-tert-butyl)-2-phenylethane (40 mo1%
), 155 parts by weight (40 m
o1%), 1,1-bis-(3,5-dimethyl-4-hydroxyphenyl)-bala-diisopropylbenzene 9
Polymerization of ternary polycarbonate using 7 parts by weight (20 mo 1%) was performed in the same manner as in Example 1, and the viscosity average molecular weight was 18.000, and the photoelastic constant C = 28B.
The glass transition temperature Tg was 155°C.

Example 4 2.2-bis-(4-hydroxy-3-tert-butyl)-2-phenylethane 83 parts by weight (20 mo1%)
, 233 parts by weight (60 mo
1%), 2,2-bis-(3,5-dimethyl-4-hydroxyphenyl)propane 68 parts by weight (20mol1%)
Polymerization of ternary polycarbonate was carried out in the same manner as in Example 2, and the viscosity average molecular weight was 19.80.
0, photoelastic constant C=27 Brewsters,
The glass transition temperature Tg was 149°C.

Example 5 4.4; 139 parts by weight (40 mo 1%) of dihydroxy-2,2,2-dihydroxy-2,2,2-dihydroxy-(4-
155 parts by weight (40 mo1%) of hydroxy, 3-tert-butylphenyl) cyclohexane, 1,1-bis-
(3,5-dimethyl-4-hydroxyphenyl)-bara-diisopropylbenzene 97 parts by weight (20 mo1%)
Polymerization of ternary polycarbonate was carried out in the same manner as in Example 1, and the viscosity average molecular weight was 20,500.
, photoelastic constant C: 36 Brewsters, and glass transition temperature Tg=162°C.

Example 6 363 parts by weight (50 mo1%) of 4.4'-dihydroxy-2,2,2-dihydroxy-2,2,2-dimethylethane, 1,1-bis-(4
-Hydroxy-3-tert-butylphenyl) cyclohexane 78 parts by weight (20 mo1%), 2,2-bis-
Polymerization of ternary polycarbonate using 102 parts by weight (30 mo1%) of (3,5-dimethyl-4-hydroxyphenyl)propane was carried out in the same manner as in Example 2, and the viscosity average molecular weight was 21,000. Elastic constant C=
43 Brewsters, glass transition temperature Tg=1
The temperature was 70°C.

Example 7 4.4'-dihydroxy-2,2,2-) rifhenylethane 139 parts by weight (40 mo 1%), 1,1-bis-(
Ternary using 155 parts by weight (40 mo1%) of 4-hydroxy-3-tert-butylphenyl)cyclohexane and 61 parts by weight (20 mo1%) of 2,2-bis-(4-hydroxy-3-methylphenyl)propane. When the polycarbonate was polymerized in the same manner as in Example 1, the viscosity average molecular weight was 19,000, and the photoelastic constant C: 36.
Brewsters, glass transition temperature Tg=150°C
Met. Example 8 4.41 dihydroxy-2,2,2-triphenylethane 139 parts by weight (40 mo1%), 2,2-bis-(4
-Hydroxy-3-tert-butyl)-2-phenylethane 124 parts by weight (30 mo1%), 2,2-bis-
Polymerization of ternary polycarbonate using 112 parts by weight (30 mo1%) of (4-hydroxy-3-isopropylphenyl)propane was carried out in the same manner as in Example 2, and the viscosity average molecular weight was 17.500, and the photoelastic constant was C:3
7 Brewsters, glass transition temperature Tg=13
The temperature was 8°C.

Example 9 4 parts by weight of 4.4'-dihydroxy-2,2,2-)diphenylethane (50 mo1%), 2,2-bis-(
83 parts by weight (20 mo1%) of 4-hydroxy-3-tert-butyl)-2-phenylethane, 2,2-bis-
Polymerization of ternary polycarbonate using 102 parts by weight (30 mo1%) of (3,5-dimethyl-4-hydroxyphenyl)propane was carried out in the same manner as in Example 1, and the viscosity average molecular weight was 19.500. Elastic constant C=
45 Brewsters, glass transition temperature Tg=1
The temperature was 74°C.

Example 10 4.4'-dihydroxy-2,2,2-)diphenylethane 139 parts by weight (40 mo1%), 2,2-bis-(
166 parts by weight (40 mo1%) of 4-hydroxy-3-tert-butyl)-2-phenylethane, 97 parts by weight of 1,1-bis-(3,5-dimethyl,4-hydroxyphenyl)-para-diisopropylbenzene ( 20mo1%
) was used to polymerize a ternary polycarbonate in the same manner as in Example 2, and the viscosity average molecular weight was 21.50.
0, photoelastic constant C=38 Brewsters, and glass transition temperature Tg=170°C.

Example 11 4.4'-dihydroxy-2,2,2-triphenylethane 139 parts by weight (40 mo1%), 2,2-bis-(
166 parts by weight (40 mo1%) of 4-hydroxy-3-tert-butyl)-2-phenylethane, 6 parts of 2,2-bis-(4-hydroxy-3-methylphenyl)propane
When ternary polycarbonate was polymerized using 1 part by weight (20 mo1%) in the same manner as in Example 1, the viscosity average molecular weight was 20,000, and the photoelastic constant C: 39 B
The glass transition temperature was -158°C.

(Evaluation of recording properties) A recording film was attached to the polycarbonate copolymer produced as described above, and the optical recording properties were evaluated. That is, Example 1
The polycarbonate copolymer described in items 1 to 11 was molded into a mold with a diameter of 130 mm using an injection molding machine (manufactured by Awayo Seisakusho, Dynamelter).
A sputtering device (RF sputtering device, manufactured by Japan Vacuum Co., Ltd.) was formed using a Tb23.5Fe64.2co12.3 (atomic%) alloy target on this substrate. Inside, the magneto-optical recording film is formed with i, ooo shaped acid. On this recording film, inorganic glass protective films i and ooo described in Japanese Patent Application Laid-open No. 177449/1983 by the present applicant were formed using the same sputtering apparatus as above. The performance of the obtained magneto-optical disk is expressed as the CN ratio,
Evaluation was made based on BER and CN ratio change rate under conditions of 60° C. and 90 RH%. The results are shown in Table 1.

Table 1 (Note 1) CN ratio = writing power 7 mW (milliwatt), reading power 1 mW, carrier frequency IMHz,
Measured at 30KHz in the resolution band (Note 2) CN change rate (
%) = Degree of decrease in CN ratio after 30 days under conditions of 60°C and 90RH% relative to the initial CN ratio (Note 3) Comparative example = Using a conventionally known polycarbonate (Kijin Kasei Co., Ltd. AD-5503) substrate A magneto-optical disk was made using the same procedure as above.

(Effects) As is clear from the results in Table 1, the polycarbonate copolymer according to the present invention has a significantly improved CN ratio due to a decrease in birefringence value, and is also found to have excellent durability.

Claims (1)

[Claims] The following component (I) is 1 to 99 mol%, and the other component (II) is 1 to 99 mol%.
) is 1 to 30 mol% and the total of components I and II is 100%
In mole%, component I is at least two or more of the following and component II
is an aromatic polycarbonate copolymer obtained by carbonate bonding a composition arbitrarily selected from one of the following dihydric phenols, which has a glass transition temperature of 130°C or higher and a photoelastic constant of 60 Brew. Stars (B
rewsters, 10-12 m^2/N) or less. I: 2,2-bis-(4-hydroxy-3-tert-butyl)-2-phenylethane (A) 4,4'-dihydroxy-2,2,2-triphenylethane (B) 1,1- Bis-(4-hydroxy-3-tert-butylphenyl)cyclohexane (C) II: 1,1'-bis-(3,5-dimethyl-4-hydroxyphenyl)-para-diisopropylbenzene (D) 2, 2-bis-(3,5-dimethyl-4-hydroxyphenyl)propane (E) 2,2-bis-(4-hydroxy-3-methylphenyl)propane (F) 2,2-bis-(4-hydroxy -3-isopropylphenyl)propane (G)