JP2000327765A - Molding material for photorecording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a molding material for a photorecording medium which is excellent in moldability and low birefringence. SOLUTION: This molding material for a photorecording medium is made of a polycarbonate obtained by reacting 6,6'-dihydroxy-3,3,3',3'-tetramethyl-1,1'- spiroindane, 4,4'-[1,3-phenylene(1-methylethylidene)]bisphenol and a compound having three or more phenolic hydroxyl groups with a carbonate-forming compound and having a limiting viscosity of 0.3-0.5 dL/g.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to molding a polycarbonate resin optical recording medium having reduced moldability and reduced birefringence suitable for manufacturing optical recording media such as compact disks, laser disks, optical cards, MO disks, and the like. About the material.

[0002]

2. Description of the Related Art Bisphenol A type polycarbonate has recently been widely used as a base material for optical discs, taking advantage of its characteristics such as transparency, heat resistance, hydrolysis resistance and dimensional stability. However, there are some problems when using polycarbonate for optical disks.

Of the performance as an optical disk substrate, birefringence, which substantially weakens a laser beam used for reading and writing information, is the most important problem. For a material having a large birefringence, errors increase, and as a recording medium, Is inferior in reliability.

[0004] Various polycarbonate resin materials have been developed for the purpose of reducing the birefringence. (JP 6
However, in recent years, in the field of optical discs where the recording density has been increasing, the measures against birefringence cannot be said to be sufficient with these materials.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a molding material for an optical recording medium having both excellent moldability and low birefringence.

[0006]

Means for Solving the Problems The present inventors have made intensive studies to solve the conventional problems, and as a result, a branched polycarbonate resin derived from a specific bisphenol has low birefringence and good The present inventors have found that this is a high quality optical recording medium molding material having both moldability, and have completed the present invention.

[0007]

DETAILED DESCRIPTION OF THE INVENTION That is, the present invention relates to 6,6'-dihydroxy-3,3,3 ', 3'-tetramethyl-1,1'-spirobiindane, 4,4'-[1,3- Phenylene (1-methylethylidene)] bisphenol, and an optical recording medium comprising a polycarbonate having an intrinsic viscosity of 0.3 to 0.5 dl / g obtained by reacting a compound having a phenolic hydroxyl group having three or more functional groups with a carbonate-forming compound. Molding material.

Examples of the carbonate-forming compound include phosgene and bisaryl carbonates such as diphenyl carbonate, di-p-tolyl carbonate, phenyl-p-tolyl carbonate, di-p-chlorophenyl carbonate, and dinaphthyl carbonate.
These compounds can be used in combination of two or more.

The polycarbonate of the present invention is bisphenol A [2,2-bis (4-hydroxyphenyl) propane]
Known methods used in the production of polycarbonate from cellulose, such as a direct reaction between bisphenols and phosgene (phosgene method) or a transesterification reaction between bisphenols and bisaryl carbonate (ester exchange method). Can be adopted.

In the former phosgene method, 6,6′-dihydroxy-3,3,3 ′, 3′-tetramethyl-1,1′-spirobiindane is usually used in the presence of an acid binder and a solvent.
4,4 '-[1,3-phenylene (1-methylethylidene)] bisphenol and a compound having a phenolic hydroxyl group having three or more functional groups are reacted with phosgene. As the acid binder, for example, pyridine, hydroxides of alkali metals such as sodium hydroxide, potassium hydroxide and the like are used.
As the solvent, for example, methylene chloride, chloroform, chlorobenzene, xylene and the like are used. Further, a tertiary amine catalyst such as triethylamine and a catalyst such as a quaternary ammonium salt are used to promote the polycondensation reaction. To control the degree of polymerization, a monofunctional compound such as a phenol represented by phenol, pt-butylphenol, p-cumylphenol or the like is added as a molecular weight regulator. Further, if desired, a small amount of an antioxidant such as sodium sulfite or hydrosulfite may be added. The reaction is usually carried out at 0 to 150 ° C., preferably 5 to 150 ° C.
It is appropriate to be in the range of -40 ° C. The reaction time depends on the reaction temperature, but is usually 5 minutes to 10 hours, preferably 10 minutes to 2 hours. During the reaction, it is desirable to maintain the pH of the reaction system at 10 or more.

On the other hand, in the latter transesterification method,
6,6'-dihydroxy-3,3,3 ', 3'-tetramethyl-1,1'-
Spirobiindane, 4,4 '-[1,3-phenylene (1-methylethylidene)] bisphenol, and a compound having a phenolic hydroxyl group having three or more functional groups and a bisaryl carbonate are mixed and reacted at a high temperature under reduced pressure. .
At this time, a monofunctional compound such as pt-butylphenol and p-cumylphenol may be added as a molecular weight regulator. The reaction is usually performed at 150 to 350 ° C., preferably 200
The reaction is carried out at a temperature in the range of -300 ° C, and the degree of reduced pressure is preferably adjusted to 1 mmHg or less. Phenols derived from the bisaryl carbonate produced by the transesterification are distilled out of the system. The reaction time depends on the reaction temperature and the degree of pressure reduction.
About 6 hours. The reaction is preferably performed in an atmosphere of an inert gas such as nitrogen or argon. If desired, the reaction may be carried out by adding an antioxidant.

In the phosgene method and the transesterification method, 6,6 ′
-Considering the reactivity of dihydroxy-3,3,3 ', 3'-tetramethyl-1,1'-spirobiindane and 4,4'-[1,3-phenylene (1-methylethylidene)] bisphenol The phosgene method is more preferred.

Further, as the molecular weight regulator of the present invention, monohydric phenols are preferable, and specifically, butylphenol, octylphenol, nonylphenol, decanylphenol, tetradecanylphenol, heptadecanylphenol, octadecanylphenol Long-chain alkyl-substituted phenols, such as butyl hydroxybenzoate, octyl hydroxybenzoate, nonyl hydroxybenzoate, decanyl hydroxybenzoate, heptadecanyl hydroxybenzoate, etc .; long-chain alkyl esters of hydroxybenzoic acid; butoxyphenol, octyloxyphenol, nonyl Long-chain alkyloxy such as oxyphenol, decanyloxyphenol, tetradecanyloxyphenol, heptadecanyloxyphenol, and octadecanyloxyphenol Phenols are exemplified.

When the phosgene method is employed in the present invention, it is preferable to add a small amount of a quaternary ammonium salt in order to carry out the reaction efficiently after the completion of the phosgene blowing.
Specific examples include tetramethylammonium chloride, trimethylbenzylammonium chloride, triethylbenzylammonium chloride, tetraethylammonium bromide, and tetra-n-butylammonium iodide. Of these, trimethylbenzylammonium chloride and triethylbenzylammonium chloride are preferred. This quaternary ammonium salt, based on all bisphenols used,
Generally, 0.0005 to 5 mol% is preferably used. 4th
It is preferable to polymerize by adding a tertiary amine such as triethylamine and a molecular weight regulator 3 to 10 minutes after the addition of the quaternary ammonium salt. The addition amount of the tertiary amine is 0.01 to 1.0 mol% based on all bisphenols. The amount of the molecular weight modifier to be added is 3 to 10 mol% based on all bisphenols.

Examples of the compound having a phenolic hydroxyl group having three or more functional groups which act as a branching agent in the present invention include phloroglucin, 2,4,4'-trihydroxybenzophenone,
2,4,4'-trihydroxyfugenyl ether, 2,2-bis (2,4-dihydroxyphenyl) propane, 2,2 ', 4,4'-
Tetrahydroxydiphenylmethane, 2,4,4'-trihydroxydiphenylmethane, 2,4,6-tris (4-hydroxyphenyl) -2,6-dimethyl-heptene-3,2,4,6-tris (4-hydroxy Phenyl) -4,6-dimethyl-heptane-2,
2,6-bis (2-hydroxy-5-methylbenzyl) -4-methylphenol, 2,6-bis (2-hydroxy-5-isopropylbenzyl) -4-isopropylphenol, tetrakis (4-
Hydroxyphenyl) methane, α, α ', α "-tris (4-
(Hydroxyphenyl) -1,3,5-triisopropylbenzene, 4,4 ′-[1- [4- [1- (4-hydroxyphenyl) -1-methylethyl] phenyl] ethylidene] bisphenol,
1,1-tris (4-hydroxyphenyl) methane, 1,1,1-tris (4-hydroxyphenyl) ethane, 1,1,1-tris (4-hydroxyphenyl) propane, 1,1,1-tris (2-
Methyl-4-hydroxyphenyl) methane, 1,1,1-tris (2-methyl-4-hydroxyphenyl) ethane, 1,1,1-tris (3-methyl-4-hydroxyphenyl) methane, 1,1 ,
1-tris (3-methyl-4-hydroxyphenyl) ethane,
1,1,1-tris (3,5-dimethyl-4-hydroxyphenyl)
Methane, 1,1,1-tris (3,5-dimethyl-4-hydroxyphenyl) ethane, 1,1,1-tris (3-chloro-4-hydroxyphenyl) methane, 1,1,1-tris ( 3-chloro-4-hydroxyphenyl) ethane, 1,1,1-tris (3,5-dichloro-4-hydroxyphenyl) methane, 1,1,1-tris (3,5-
Dichloro-4-hydroxyphenyl) ethane, 1,1,1-tris (3-bromo-4-hydroxyphenyl) methane, 1,1,1-
Tris (3-bromo-4-hydroxyphenyl) ethane, 1,
1,1-tris (3,5-dibromo-4-hydroxyphenyl) methane, 1,1,1-tris (3,5-dibromo-4-hydroxyphenyl) ethane, 1,1,1-tris (3- Fluoro-4-hydroxyphenyl) methane, 1,1,1-tris (3-fluoro-4-hydroxyphenyl) ethane, 1,1,1-tris (3,5-difluoro-4-hydroxyphenyl) methane, 1 , 1,1-tris (3,5-difluoro-4-hydroxyphenyl) ethane,
Examples thereof include 1,1-tris (4-hydroxyphenyl) -1-phenylmethane. Among them, 1,1,1-tris (4-hydroxyphenyl) ethane, 4,4 ′-[1- [4- [1- (4-hydroxyphenyl) -1-methylethyl] phenyl] ethylidene]
Bisphenol and 2,4,6-tris (4-hydroxyphenyl) -2,6-dimethyl-3-heptene are most preferred from the viewpoint of reactivity and ease of handling.

Further, the compound having a trifunctional or higher phenolic hydroxyl group serving as a branching agent includes 6,6′-dihydroxy-3,3,3 ′, 3′-tetramethyl-1,1′-spirobiindane; It is preferable to add 0.2 to 3.0 mole parts of a compound having a phenolic hydroxyl group having three or more functional groups with respect to 100 mole parts in total of 4,4 '-[1,3-phenylene (1-methylethylidene)] bisphenol. . If the amount is less than 0.2 mol part, the effect of improving fluidity is low, and if it exceeds 3.0 mol part, the impact resistance becomes poor.

Further, according to the present invention, 6,6′-dihydroxy-3,3,3 ′, 3′-tetramethyl-1,1′-spirobiindane,
The molar ratio used with 4,4 ′-[1,3-phenylene (1-methylethylidene)] bisphenol is preferably from 1: 9 to 9: 1.
If the amount of 6,6′-dihydroxy-3,3,3 ′, 3′-tetramethyl-1,1′-spirobiindane is less than 10%, the heat resistance is lowered and the effect of improving birefringence becomes insufficient. When 6,6′-dihydroxy-3,3,3 ′, 3′-tetramethyl-1,1′-spirobiindane exceeds 90%, a high molecular weight substance having an intrinsic viscosity of 0.3 dl / g or more can be obtained. Becomes difficult.

The polycarbonate polymer synthesized by these reactions can be molded by a known molding method such as extrusion molding, injection molding, blow molding, compression molding, or wet molding. It is desirable that extrusion and injection molding can be easily performed, and in particular, in the case of precision molding for optical recording media, the intrinsic viscosity is preferably in the range of 0.3 to 0.5 dl / g.

The polycarbonate molding material for an optical recording medium of the present invention is preferably molded by injection molding. If the fluidity is too large or too small, there is a problem in moldability. For example, Koka type flow tester (280 ° C, 160kgf / c
m ² , nozzle diameter 1mm x 10mm) measurement, 15 ~ 90 × 10 ^-2 cc / sec
Is preferable. If the flow rate is less than 15 × 10 ^-2 cc / sec, the fluidity is poor and poor filling into the mold or a flow mark may occur.If the flow rate exceeds 90 × 10 ^-2 cc / sec, mold release failure or warpage is likely to occur. .

The polycarbonate molding material for an optical recording medium of the present invention must be highly refined as in the case of a general polycarbonate for an optical disk. Specifically, dust having a diameter of 50 μm or more is substantially not detected, dust having a diameter of 0.5 to 50 μm is 3 × 10 ⁴ or less, inorganic and organic residual chlorine is 2 ppm or less, residual alkali metal is 2 ppm or less, and residual hydroxyl group Purification is performed so as to satisfy the criteria as low as possible, such as 200 ppm or less, residual nitrogen amount 5 ppm or less, and residual monomer 20 ppm or less. In some cases, post-treatment such as extraction is performed to remove low molecular weight substances or remove solvents.

The polycarbonate molding material for an optical recording medium is provided with a hindered phenol-based or phosphite-based antioxidant; Lubricants and mold release agents such as ester, fatty acid, fatty acid glyceride, beeswax and other natural fats and oils; benzotriazole, benzophenone, dibenzoylmethane, and salicylate light stabilizers; polyalkylene glycol, fatty acid glyceride, etc. An antistatic agent or the like may be appropriately used in combination, and furthermore, it is also possible to mix and use the polycarbonate with a general polycarbonate for an optical recording medium arbitrarily from the viewpoint of cost and the like as long as the performance is not impaired. The molding temperature when the present molding material is injection-molded is preferably 280 to 380 ° C from the viewpoint of fluidity.

[0022]

Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

Example 1 6,6′- was added to 58 liters of an aqueous 8.8% (w / v) sodium hydroxide solution.
2.46 kg of dihydroxy-3,3,3 ', 3'-tetramethyl-1,1'-spirobiindane (hereinafter abbreviated as SPI, 8 mol), 4,4'-[1,3-
Phenylene (1-methylethylidene)] bisphenol 11.0
7 kg (hereinafter abbreviated as BPM, 32 mol), 244.8 g of 1,1,1-tris (4-hydroxyphenyl) ethane (hereinafter abbreviated as THPE, 0.
8 mol) and 10 g of hydrosulfite were added and dissolved.
To this, 36 liters of methylene chloride was added, and 5 kg of phosgene was blown in over 50 minutes while stirring at 15 ° C. After completion of the blowing, 5 g (0.022 mol) of triethylbenzylammonium chloride was added, and the mixture was vigorously stirred for 5 minutes to emulsify the reaction solution.
0 g (hereinafter abbreviated as PTBP, 3.8 mol) was added, and 20 ml of triethylamine (0.14 mol) was further added, followed by stirring for about 1 hour to carry out polymerization. The polymerization liquid was separated into an aqueous phase and an organic phase, the organic phase was neutralized with phosphoric acid, and the water washing was repeated until the conductivity of the washing liquid became 10 μS or less, to obtain a purified resin liquid. The obtained purified resin liquid was slowly dropped into 45 ° C. hot water under vigorous stirring to solidify the polymer while removing the solvent. The solid was filtered and dried to obtain a white powdery polymer. This polymer had an intrinsic viscosity [η] of 0.38 dl / g at a temperature of 20 ° C. in a solution having a concentration of 0.5 g / dl using methylene chloride as a solvent. As a result of analyzing the obtained polymer from an infrared absorption spectrum, absorption by a carbonyl group was observed at a position near 1770 cm ⁻¹ , and it was confirmed that the polymer had a carbonate bond. Also, almost no absorption derived from hydroxyl groups was observed at the position of 3650 to 3200 cm ^-1 . When the monomers in this polycarbonate were measured by GPC analysis, all the monomers were 20 ppm or less.

To the obtained polycarbonate powder, 300 ppm of stearic acid monoglyceride was added, and the mixture was treated with a vented 50 mm extruder equipped with a 50 μm polymer filter.
C. and extruded to form a melt pellet. The obtained pellets were obtained at a resin temperature of 350 ° C., a mold temperature of 100 ° C., and an injection pressure of 29.4 MPa, with an outer diameter of 120 mm and a thickness of 1.
A 2 mm disk was injection molded, and after being left indoors for 2 days, the birefringence at 30 ° oblique incidence was measured. For the extruded pellets, the flow value (Q value) was measured and used as a measure of molding fluidity. For the polycarbonate powder, a cast film having a thickness of 50 μm was prepared, a load of 300 to 1100 g was applied, and the photoelastic sensitivity was measured. The results are shown in Table 1.

Example 2 4.93 kg (16 mol) of SPI, 8.30 kg (24 mol) of BPM, and THPE
The procedure was performed in the same manner as in Example 1 except that 183.6 g (0.6 mol) and PTBP were changed to 510 g (3.4 mol). The intrinsic viscosity [η] of the obtained polymer was 0.35 dl / g, and this polymer was recognized as a polycarbonate polymer having the same structure as that of Example 1 except for the degree of branching by infrared absorption spectrum analysis or the like. Was. The results are shown in Table 1.

Example 3 6.16 kg (20 mol) of SPI, 6.92 kg (20 mol) of BPM and THPE
The procedure was performed in the same manner as in Example 1 except that 122.4 g (0.4 mol) and PTBP were changed to 450 g (3.0 mol). The intrinsic viscosity [η] of the obtained polymer was 0.33 dl / g. From infrared absorption spectrum analysis and the like, this polymer was recognized as a polycarbonate polymer having the same structure as that of Example 1 except for the degree of branching. Was. The results are shown in Table 1.

EXAMPLE 4 8.62 kg (28 mol) of SPI, 4.15 kg (12 mol) of BPM and THPE
The procedure was performed in the same manner as in Example 1 except that 61.2 g (0.2 mol) and PTBP were changed to 360 g (2.4 mol). The intrinsic viscosity [η] of the obtained polymer was 0.34 dl / g, and the polymer was recognized as a polycarbonate polymer having the following structural units from infrared absorption spectra and the like. The results are shown in Table 1.

Comparative Example 1 In place of the polycarbonate of Example 1, 2,2-bis (4-hydroxyphenyl) propane (hereinafter, referred to as a commercially available optical recording medium) was used.
BPA) type polycarbonate (Mitsubishi Gas Chemical Co., Ltd.)
Example 1 using H-4000 ([η] = 0.35dl / g).
The same test was performed. The results are shown in Table 1.

Comparative Example 2 Using only 12.32 kg (40 mol) of SPI without BPM and THPE,
The procedure was performed in the same manner as in Example 1 except that BP was changed to 360 g (2.4 mol). Due to poor reactivity with phosgene, polymerization did not proceed and physical properties could not be evaluated.

Comparative Example 3 Without using SPI and THPE, using 13.84 kg (40 mol) of only BPM,
The procedure was performed in the same manner as in Example 1 except that BP was changed to 288 g (1.92 mol). The intrinsic viscosity [η] of the obtained polymer is 0.35 dl / g
From the infrared absorption spectrum and the like, this polymer was confirmed to be a polycarbonate polymer having the following structural units.

Comparative Example 4 Without using BPM, using 12.32 kg (40 mol) of only SPI,
The procedure was performed in the same manner as in Example 1, except that 2.4 g (0.4 mol) and PTBP were changed to 360 g (2.4 mol). Due to poor reactivity with phosgene, polymerization did not proceed and physical properties could not be evaluated.

[0032]

[Table 1]

[Explanation of Table 1] Birefringence: Automatic ellipsometer manufactured by Mizojiri Optical Co., Ltd.
Measurement wavelength: 632.8 nm. Flow value (Q value): Shimadzu Corporation's high-grade flow tester is used. 280 ℃, 160kgf / cm ^2, the flow rate per unit time in the nozzle diameter 1 mm × 10 mm conditions. (Unit × 10 ^-2 cc / sec) Photoelastic sensitivity: 300-1100g on a 50μm cast film
At a wavelength of 632.8 mm with an ellipsometer.
Measure photoelastic sensitivity. SPI: 6,6'-dihydroxy-3,3,3 ', 3'-tetramethyl-1,
1'-spirobiindane BPM: 4,4 '-[1,3-phenylenebis (1-methylethylidene)] bisphenol BPA: 2,2-bis (4-hydroxyphenyl) propane THPE: 1,1,1-tris ( 4-hydroxyphenyl) ethane PTBP: p-tert-butylphenol BP component (a): Ratio of total bisphenol used in SPI (mol%) BP component (b): Ratio of BPM to total bisphenol used (mol%) ) Intrinsic viscosity: 0.5g / 100cc dichloromethane resin solution 20
The intrinsic viscosity [η] (dl / g) was determined at 0 ° C. and the Huggins constant of 0.45.

[0034]

According to the present invention, it is possible to provide a molding material for an optical recording medium having both excellent moldability and low birefringence. In particular,
It is suitable for rewritable optical disks and magneto-optical disks that require high-density recording and reliability.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G02B 1/04 G02B 1/04 G11B 7/24 526 G11B 7/24 526G (72) Inventor Noriaki Honda Osaka, Osaka 2-12 Jinshu-cho, Toyonaka City F-term (reference) 4J029 AA09 AB04 AB07 AC02 AD01 AE05 AE18 BD02 FA07 FC33 GA02 GA65 HA01 HC01 JA091 JC041 JC091 KB17 KB24 KB25 KE09 5D029 KA07 KC07

Claims (7)

[Claims] 1. A 6,6′-dihydroxy-3,3,3 ′, 3′-tetramethyl-1,1′-spirobiindane, 4,4 ′-[1,3-phenylene (1-methylethylidene)] Bisphenol, and 3
The intrinsic viscosity obtained by reacting a compound having a functional or higher phenolic hydroxyl group with a carbonate-forming compound has a limiting viscosity of 0.3.
A molding material for an optical recording medium, comprising a polycarbonate having a weight of 0.5 dl / g. (2) 6,6′-dihydroxy-3,3,3 ′, 3′-tetramethyl-1,1′-spirobiindane and 4,4 ′-[1,3-phenylene (1-methylethylidene) The molding material for an optical recording medium according to claim 1, wherein the molar ratio of the bisphenol to bisphenol is 1: 9 to 9: 1. (3) 6,6′-dihydroxy-3,3,3 ′, 3′-tetramethyl-1,1′-spirobiindane and 4,4 ′-[1,3-phenylene (1-methylethylidene) ] Total of bisphenol 1
2. The molding material for an optical recording medium according to claim 1, wherein a compound having a phenolic hydroxyl group having three or more functional groups is added in an amount of 0.2 to 3.0 mol parts per 100 mol parts. 4. The compound having a phenolic hydroxyl group having three or more functional groups is 1,1,1-tris (4-hydroxyphenyl).
Ethane, 4,4 '-[1- [4- [1- (4-hydroxyphenyl) -1-
Methylethyl] phenyl] ethylidene] bisphenol and 2,4,6-tris (4-hydroxyphenyl) -2,6-
2. The molding material for an optical recording medium according to claim 1, wherein the molding material is at least one selected from the group consisting of dimethyl-3-heptene. 5. In the presence of an aqueous alkali solution and an organic solvent,
6,6'-dihydroxy-3,3,3 ', 3'-tetramethyl-1,1'-spirobiindane, 4,4'-[1,3-phenylene (1-methylethylidene)] bisphenol, and trifunctional After blowing phosgene into the compound having the phenolic hydroxyl group, a quaternary ammonium salt is added to start the polycondensation reaction, and then a monohydric phenol serving as a molecular weight regulator is added,
2. The method for producing a molding material for an optical recording medium according to claim 1, wherein a tertiary amine polymerization catalyst is further added to accelerate the polycondensation. 6. The method for producing a molding material for an optical recording medium according to claim 5, wherein the molecular weight modifier and the tertiary amine are simultaneously added. 7. The method for producing a molding material for an optical recording medium according to claim 5, wherein the quaternary ammonium salt is triethylbenzylammonium chloride or trimethylbenzylammonium chloride.