JP2001055435A - Molding material for optical recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject molding material having the moldability suitable for producing optical recording media such as a compact disk or a laser disk compatible with low birefringence properties by composing the molding material of a specific polycarbonate specified two kinds of bisphenol compounds. SOLUTION: This molding material is composed of a polycarbonate prepared by reacting (A) a bisphenol compound represented by the formula (R1 to R4 are each H, a 1-5C alkyl, a 6-12C aryl, a 2-5C alkenyl, a 1-5C alkoxy or a 7-17C aralkyl) [e.g. 9,9-bis (4-hydroxyphenyl)fluorene] with (B) 4, 4'-[1, 3- phenylenebis(1-methylethylidene)]bisphenol and (C) a compound having a tri- or a polyfunctional phenolic hydroxyl group [e.g. 1,1,1-tris(4-hydroxyphenyl) ethane] and a carbonic ester-forming compound and has 0.3-0.5 dL/g intrinsic viscosity. The components A and B are preferably used in (1:9) to (9:1) molar ratio.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a compact disc, a laser disc (registered trademark), an optical card, and an MO card.
The present invention relates to a molding material for a polycarbonate resin optical recording medium having reduced moldability and reduced birefringence suitable for producing an optical recording medium such as a disk.

[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]

The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, a branched polycarbonate resin derived from a specific bisphenol has a low birefringence and a good birefringence. 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 a compound represented by the general formula (A):
Intrinsic viscosity obtained by reacting a bisphenol compound of formula (I), 4,4 '-[1,3-phenylenebis (1-methylethylidene)] bisphenol, a compound having a phenolic hydroxyl group having three or more functional groups with a carbonate-forming compound Is from 0.3 to 0.5 dl / g.

Embedded image (Wherein, R _{1 to} R ₄ are each independently a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, an aryl group having 6 to 12 carbon atoms,
Represents an alkenyl group having 2 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms or an aralkyl group having 7 to 17 carbon atoms. )

As the bisphenol compound of the general formula (A) of the present invention, specifically, 9,9-bis (4-hydroxyphenyl) fluorene, 9,9-bis (4-hydroxy-2-methylphenyl) Fluorene, 9,9-bis (4-hydroxy-3-methylphenyl) fluorene,
3,6-dimethyl-9,9-bis (4-hydroxyphenyl) fluorene, 9,9-bis (3-methoxy-4-
(Hydroxyphenyl) fluorene, 9,9-bis (3-
Ethoxy-4-hydroxyphenyl) fluorene, 9,
9-bis (3-ethyl-4-hydroxyphenyl) fluorene, 4,5-dimethyl-9,9-bis (4-hydroxyphenyl) fluorene, 9,9-bis (3-phenyl-4hydroxyphenyl) fluorene, Examples thereof include 3,6-dimethyl-9,9-bis (3-methyl-4-hydroxyphenyl) fluorene and 3,6-diphenyl-9,9-bis (4-hydroxyphenyl) fluorene. In particular, 9,9-bis (4-hydroxyphenyl) fluorene, 9,9-bis (4-hydroxy-2)
-Methylphenyl) fluorene and 9,9-bis (4-
(Hydroxy-3-methylphenyl) fluorene is preferred.

In the present invention, the bisphenol compound of the general formula (A) and 4,4 ′-[1,3-phenylenebis (1-methylethylidene)] bisphenol are used in a molar ratio of 1: 9 to 9: A ratio of 1 is preferred. If the content of the bisphenol compound of the general formula (A) is less than 10%, the fluidity becomes too high, which may cause problems in moldability, and at the same time the effect of improving birefringence becomes insufficient. On the other hand, when the bisphenol compound of the general formula (A) exceeds 90%, the fluidity becomes poor and molding becomes difficult.

In the present invention, the compound having a phenolic hydroxyl group having three or more functional groups acting as a branching agent includes:
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, a compound having a trifunctional or higher phenolic hydroxyl group serving as a branching agent is represented by the general formula (A):
And a compound having a phenolic hydroxyl group having three or more functional groups was defined as 0 relative to a total of 100 mol parts of a bisphenol compound of the formula (1) and bisphenols composed of 4,4 '-[1,3-phenylenebis (1-methylethylidene)] bisphenol. It is preferable to add 0.2 to 3.0 mole parts. 0.
If it is less than 2 mole parts, the fluidity improving effect is low, and if it exceeds 3.0 mole parts, the impact resistance becomes poor.

The polycarbonate of the present invention can be produced by a known method used for producing a polycarbonate from bisphenol A [2,2-bis (4-hydroxyphenyl) propane], for example, a direct reaction of bisphenols with phosgene (phosgene). Method) or a method of transesterification of a bisphenol with a diaryl carbonate (ester exchange method).

In the former phosgene method, the bisphenol compound of the general formula (A), 4,4 '-[1,3-phenylenebis (1-methylethylidene)] bisphenol is usually used in the presence of an acid binder and a solvent. And a compound having a phenolic hydroxyl group having three or more functions is 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 accelerate the polycondensation reaction. To control the degree of polymerization, a monofunctional compound of a phenol represented by phenol, pt-butylphenol, p-cumylphenol or the like is added as a molecular weight regulator.
Further, if necessary, a small amount of an antioxidant such as sodium sulfite or hydrosulfite may be added. The reaction is usually carried out at a temperature of 0 to 150 ° C, preferably 5 to 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,
A bisphenol compound of the general formula (A),
4 ′-[1,3-phenylenebis (1-methylethylidene)] bisphenol and a compound having a phenolic hydroxyl group having three or more functional groups are mixed with a diaryl carbonate, and reacted at a high temperature under reduced pressure. At this time, p
Monofunctional compounds of phenols such as -t-butylphenol and p-cumylphenol may be added as a molecular weight regulator. The reaction is usually performed at a temperature in the range of 150 to 350 ° C., preferably 200 to 300 ° C., and the degree of reduced pressure is preferably adjusted to 1 mmHg or less finally.
Phenols derived from the diaryl carbonate generated by the transesterification are distilled out of the system. The reaction time depends on the reaction temperature and the degree of vacuum,
It is usually about 1 to 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, the bisphenol compound of the general formula (A) and 4,4'-
[1,3-phenylenebis (1-methylethylidene)]
In consideration of the reactivity of bisphenol, the phosgene method is preferred.

Further, as the molecular weight regulator of the present invention, a monohydric phenol is 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.

In the present invention, when the phosgene method is employed, 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 exemplified. Is preferred. This quaternary ammonium salt is generally preferably used in an amount of 0.0005 to 5 mol% based on all bisphenols used. After addition of the quaternary ammonium salt, 3 to 1
After 0 minute, it is preferable to carry out polymerization by adding a tertiary amine such as triethylamine and a molecular weight regulator. The addition amount of the tertiary amine is 0.01 to the total bisphenols.
~ 1.0 mol%. The amount of the molecular weight modifier added is 3 to 10 mol% based on all bisphenols.

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. In particular, in the case of precision molding for an optical recording medium, 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 release agents such as ester, fatty acid, fatty acid glyceride, beeswax and other natural fats and oils; benzotriazole, benzophenone, dibenzoylmethane, salicylate and other light stabilizers; polyalkylene glycol, fatty acid glyceride, etc. An antistatic agent or the like may be appropriately used in combination, and furthermore, it is possible to use it arbitrarily by mixing it with ordinary polycarbonate for optical recording media within the range that does not impair the performance in terms of cost and the like. The molding temperature when the present molding material is injection-molded is preferably from 280 to 380 ° C from the viewpoint of fluidity.

[0022]

Next, the present invention will be described in more detail by way of examples, which should not be construed as limiting the present invention.

Example 1 58 liters of an 8.8% (w / v) aqueous sodium hydroxide solution
9,9-bis (4-hydroxyphenyl) fur
4.2 kg of oren (hereinafter abbreviated as BPFL, 12 mol)
And 4,4 '-[1,3-phenylenebis (1-methyl
9.69 Kg of bisphenol (BPM)
Abbreviation, 28 mol) and 1,1,1-tris (4-hydr
Roxyphenyl) ethane 122 g (hereinafter abbreviated as THPE)
0.4 mol) and 10 g of hydrosulfite
Added and dissolved. 36 liters of methylene chloride
Phosgene 5k while stirring at 15 ° C.
g over 50 minutes. After blowing, trie
5 g of tylbenzylammonium chloride (0.022
mol) and stirred vigorously for 5 minutes to emulsify the reaction solution.
And then 504 g of p-tert-butylphenol (hereinafter referred to as).
Lower PTBP, abbreviated to 3.36 mol), and 2
0 ml of triethylamine (0.14 mol) was added,
The mixture was stirred and polymerized for about 1 hour. Separate the polymerization liquid into aqueous and organic phases
Separate and neutralize the organic phase with phosphoric acid, the conductivity of the washing solution is 10μ
After repeated washing with water until it becomes S or less, a purified resin liquid is obtained.
Was. The obtained purified resin solution was stirred at 45 ° C. under strong stirring.
Drop the solvent slowly into warm water to remove the solvent and solidify the polymer.
It has become. After filtering the solid matter, it is dried to obtain a white powdery polymer.
Obtained. This polymer has a concentration of methylene chloride as a solvent.
Intrinsic viscosity of a 0.5 g / dl solution at a temperature of 20 ° C.
[Η] was 0.41 dl / g. The above polymerization obtained
As a result of analyzing the body from the infrared absorption spectrum, 1770
cm ^-1Absorption by carbonyl group was observed in the vicinity
It was confirmed that the compound had a carbonate bond. Ma
3650-3200cm^-1At the position
Little yield was observed. This polycarbonate
When the monomer in the sample was measured by GPC analysis,
Nomer was also 20 ppm or less.

To the obtained polycarbonate powder, 300 ppm of stearic acid monoglyceride was added, and the mixture was extruded at 300 ° C. using a vented 50 mm extruder equipped with a 50 μm polymer filter to form a melt pellet. The obtained pellets were heated at a resin temperature of 350 ° C, a mold temperature of 100 ° C,
And an injection pressure of 29.4 MPa, an outer diameter of 120 mm,
A disk having a thickness of 1.2 mm 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 polycarbonate powder, 50 μm
A thick cast film 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 7.0 kg (20 mol) of BPFL and 6.9 of BPFL
Change to 2kg (20mol), THPE 122g
(0.4 mol), 522 g of PTBP (3.48 mol)
Except having changed to l), it carried out similarly to Example 1. The intrinsic viscosity [η] of the obtained polymer was 0.38 dl / g, and it was confirmed by infrared absorption spectrum analysis and the like that this polymer had the same polycarbonate polymer structure as in Example 1 except for the polymerization ratio. . The results are shown in Table 1.

Example 3 9.8 kg (28 mol) of BPFL and 4.1 of BPM
Change to 5kg (12mol), THPE 61.2g
(0.2 mol), 504 g of PTBP (3.36 mol)
Except having changed to l), it carried out similarly to Example 1. The intrinsic viscosity [η] of the obtained polymer was 0.39 dl / g, and this polymer had a polycarbonate polymer structure equivalent to that of Example 1 except for the polymerization ratio and the degree of branching from infrared absorption spectrum analysis and the like. It was accepted. The results are shown in Table 1.

Example 4 Instead of BPFL, 9,9-bis (4-hydroxy-3
7.56 kg (hereinafter referred to as B)
(CFL, abbreviated as 20 mol) was performed in the same manner as in Example 2. The intrinsic viscosity [η] of the obtained polymer was 0.37 dl / g, and as a result of analysis by 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. Was. Also, almost no hydroxyl-derived absorption was observed at 3650 to 3200 cm ^-1 . When the monomers in this polycarbonate were measured by GPC analysis, all the monomers were 20 ppm or less. The results are shown in Table 1.

Comparative Example 1 Instead of the polycarbonate of Example 1, a 2,2-bis (4-hydroxyphenyl) propane (hereinafter abbreviated as BPA) type polycarbonate for commercial optical recording media (H-manufactured by Mitsubishi Gas Chemical Co., Ltd.) 4000, [η] = 0.35 dl / g)
And the same test as in Example 1 was performed. The results are shown in Table 1.

Comparative Example 2 BPFL and BCFL were not used and only BPM was 13.84K.
g (40 mol), and 288 g (1.92 g) of PTBP.
mol), the same procedure as in Example 1 was carried out.
The intrinsic viscosity [η] of the obtained polymer is 0.35 dl / g.
The polymer was confirmed to be a polycarbonate polymer from infrared absorption spectrum and the like. The results are shown in Table 1.

Comparative Example 3 14 kg (40 mol) of BPFL alone without using BPM
It carried out similarly to Example 1 except having used and changing PTBP to 366 g (2.44 mol). The reactivity of BPFL was poor, a large amount of unreacted monomer was generated, and molding was impossible due to insufficient strength. The results are shown in Table 1.

[0031]

[Table 1]

[Explanation of Table 1] Birefringence: Automatic ellipsometer manufactured by Mizojiri Optical Industry Co., Ltd.
Measurement wavelength 632.8nm. Photoelasticity sensitivity: 300 to 1100 for a 50 μm thick cast film
g was applied and the photoelastic sensitivity was measured at an ellipsometer wavelength of 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 ml / sec) BPFL: 9,9-bis (4-hydroxyphenyl) fluorene BCFL: 9,9-bis (4-hydroxy-3-methylphenyl) fluorene BPM: 4,4 '-[ 1,3-phenylenebis (1-methylethylidene)] bisphenol THPE: 1,1,1-tris (4-hydroxyphenyl) ethane BP component (a): Ratio of the general formula (A) to the total amount of bisphenol used (mol %) BP component (b): BP based on the total amount of bisphenol used
M ratio (mol%) Intrinsic viscosity: 0.5 g / 100 cc
The intrinsic viscosity [η] (dl / g) was determined at 0 ° C. and the Huggins constant of 0.45.

[0033]

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.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Noriaki Honda 2-12-12, Kanshu-cho, Toyonaka-shi, Osaka Prefecture F-term in Mitsubishi Gas Chemical Co., Ltd. Osaka Plant JC091 KB17 KB25 5D029 KA07 KC07

Claims (8)

[Claims] 1. A bisphenol compound of the general formula (A), 4,4 ′-[1,3-phenylenebis (1-methylethylidene)] bisphenol, a compound having a phenolic hydroxyl group having three or more functional groups, and a carbonate ester The intrinsic viscosity obtained by reacting with the forming compound is 0.3 to 0.5.
dl / g, a molding material for an optical recording medium comprising polycarbonate. Embedded image (Wherein, R _{1 to} R ₄ are each independently a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, an aryl group having 6 to 12 carbon atoms,
Represents an alkenyl group having 2 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms or an aralkyl group having 7 to 17 carbon atoms. ) 2. The bisphenol compound of the general formula (A) and 4,4 ′-[1,3-phenylenebis (1-
2. The molding material for an optical recording medium according to claim 1, wherein the molar ratio of the methylethylidene) to bisphenol is 1: 9 to 9: 1. 3. The bisphenol compound of the general formula (A) and 4,4 ′-[1,3-phenylenebis (1-
2. The 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 based on 100 mol parts of bisphenols composed of bisphenol. Molding materials. 4. The bisphenol compound represented by the general formula (A) is 9,9-bis (4-hydroxyphenyl) fluorene, 9,9-bis (4-hydroxy-3-
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 methylphenyl) fluorene and 9,9-bis (4-hydroxy-2-methylphenyl) fluorene. 5. 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-hydroxy Phenyl) -1-methylethyl] phenyl] ethylidene] bisphenol, and at least one selected from the group consisting of 2,4,6-tris (4-hydroxyphenyl) 2,6-dimethyl-3-heptene. Item 7. A molding material for an optical recording medium according to Item 1. 6. In the presence of an alkaline aqueous solution and an organic solvent,
Bisphenol compound of general formula (A), 4,4′-
[1,3-phenylenebis (1-methylethylidene)]
After blowing phosgene into bisphenol and a compound having a phenolic hydroxyl group having three or more functional groups, a quaternary ammonium salt is added to start a polycondensation reaction, and then a monohydric phenol serving as a molecular weight regulator is added. 2. The method according to claim 1, further comprising adding a tertiary amine polymerization catalyst to promote polycondensation. 7. The method for producing a molding material for an optical recording medium according to claim 6, wherein the molecular weight modifier and the tertiary amine are added simultaneously. 8. The method for producing a molding material for an optical recording medium according to claim 6, wherein the quaternary ammonium salt is triethylbenzylammonium chloride or trimethylbenzylammonium chloride.