JP3486989B2 - Molding material for optical recording media - Google Patents

Description

Detailed Description of the Invention

[0001]

The present invention relates to a compact disc,
The present invention relates to a molding material for a polycarbonate resin optical recording medium, which has excellent heat resistance and moldability suitable for producing an optical recording medium such as a laser disc and an MO disc, and has reduced birefringence.

[0002]

2. Description of the Related Art Bisphenol A type polycarbonate has recently come to be widely used as a base material for optical discs due to 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 disc substrate, birefringence, which substantially weakens the laser beam used for reading and writing information, is the most important problem, and errors with large birefringence increase the reliability as a recording medium. Is inferior.

Various polycarbonate resin materials have been developed for the purpose of reducing these birefringences. (JP-A-60-215020, JP-A-62-181115) However, these birefringences cannot be said to be sufficient for the current optical discs which require further reliability. Therefore, a polycarbonate-polystyrene copolymer (PC-PS) with further reduced birefringence has been developed. (JP-A-2
-29412) The birefringence of this copolymer is greatly improved as compared with the conventional one, but since polystyrene is used, there is a problem in heat resistance and its use is limited.
Further, recently, there has been a demand for reduction of birefringence at oblique incidence, which is difficult to improve under molding conditions.

On the other hand, as a modified polycarbonate, the existence of a polycarbonate having a fluorene structure having heat resistance and selective gas permeability is known. (JP-A-48
-64199, JP-A-63-182336, JP-A-6-
192411, JP-A-6-145327)

[0005]

In view of the above circumstances, the present invention is to provide a high-quality optical recording medium molding material having both low birefringence and heat resistance.

[0006]

As a result of intensive studies to solve the conventional problems, the inventors of the present invention have found that a polycarbonate resin having a specific fluorene structure has a good birefringence and heat resistance. The present invention has been completed and the present invention has been completed.

That is, the present invention has a constitutional unit represented by the following general formula (A) and a general formula (B) having a fluorene structure, and the constitutional unit of the general formula (A) is 5 mol% in all constitutional units. The present invention provides a molding material for an optical recording medium, which is made of polycarbonate and has an intrinsic viscosity of 0.30 to 0.50 dl / g in an amount of less than 20 mol% .

[0008]

[Chemical 4]

(In the formula, R _{1 to} R ₄ are each a hydrogen atom, a fluorine atom, a chlorine atom, a bromine atom, an alkyl group having 1 to 5 carbon atoms and an aryl group having 6 to 12 carbon atoms, each of which may have a substituent. A alkenyl group having 2 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, and an aralkyl group having 7 to 17 carbon atoms, and the substituent which may be present on any of the carbon atoms of these groups has 1 carbon atom. ~ 5
Is an alkyl group or alkenyl group, an alkoxy group having 1 to 5 carbon atoms, a halogen atom selected from fluorine, chlorine and bromine, and a dimethylpolysiloxy group. However, R _{1 to} R ₂
At least one of them is a group other than a hydrogen atom. )

[0010]

[Chemical 5]

(In the formula, each of R _{5 to} R ₈ is hydrogen, fluorine, chlorine, bromine, iodine, an alkyl group having 1 to 5 carbon atoms which may have a substituent, and an alkyl group having 6 to 12 carbon atoms. An aryl group, an alkenyl group having 2 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, and an aralkyl group having 7 to 17 carbon atoms,
Substituents which may be present on any of the carbons of these groups include an alkyl group or an alkenyl group having 1 to 5 carbon atoms and a carbon number of 1
To 5 alkoxy groups, halogens selected from fluorine, chlorine, bromine and iodine, and dimethylpolysiloxy groups. X
Is a kind of group represented below.

[0012]

[Chemical 6]

Here, R ₉ and R ₁₀ each represent hydrogen, an alkyl group having 1 to 5 carbon atoms which may have a substituent, an alkoxy group or an aryl group having 6 to 12 carbon atoms, or R
₉ and R ₁₀ represent a group which is bonded together to form a carbocycle or a heterocycle, and the substituent which the carbon of these groups may have is an alkyl group or an alkenyl group having 1 to 5 carbon atoms,
It is a halogen selected from an alkoxy group having 1 to 5 carbon atoms, fluorine, chlorine, bromine and iodine. a represents an integer of 0 to 20, b and c represent an integer of 1 to 100. )

The polycarbonate of the present invention can be produced by a known method used for producing a polycarbonate from bisphenol A, for example, a direct reaction between a dihydric phenol and phosgene (phosgene method), or a dihydric phenol and a bisaryl carbonate. A method such as the transesterification reaction (transesterification method) can be adopted.

In the phosgene method and the transesterification method, the phosgene method is preferred in consideration of the reactivity of the fluorene-containing dihydric phenol that induces the structure of the general formula (A).

In the former phosgene method, a dihydric phenol that induces the general formula (B) and a fluorene-containing dihydric phenol that induces the general formula (A) in the present invention are usually used in the presence of an acid binder and a solvent. React with phosgene.

As the acid binder, for example, pyridine and hydroxides of alkali metals such as sodium hydroxide and potassium hydroxide are used, and as the solvent, for example, methylene chloride, chloroform, chlorobenzene and xylene are used. To be Further, a catalyst such as a tertiary amine such as triethylamine or a quaternary ammonium salt is used to accelerate the polycondensation reaction.

To control the degree of polymerization, phenol, p-
A monofunctional compound such as t-butylphenol, p-cumylphenol or long-chain alkyl-substituted phenol is used as the molecular weight modifier. If desired, a small amount of an antioxidant such as sodium sulfite or hydrosulfite or a branching agent such as phloroglucin or isatin bisphenol may be added.

The reaction is usually 0 to 150 ° C., preferably 5 to
A temperature in the range of 40 ° C is suitable. The reaction time depends on the reaction temperature, but is usually 0.5 minutes to 10 hours, preferably 1 minute to 2 hours. Further, it is desirable to keep the pH of the reaction system at 10 or more during the reaction.

On the other hand, in the latter transesterification method, a fluorene-containing dihydric phenol that induces the general formula (A) is mixed with a dihydric phenol that derives the general formula (B) and a bisaryl carbonate, and the mixture is heated under reduced pressure at a high temperature. React at. The reaction is usually 150 to 350 ° C., preferably 200.
It is carried out at a temperature in the range of ˜300 ° C., and the degree of vacuum is finally set to preferably 1 mmHg or less, and the phenols derived from the bisaryl carbonate produced by the transesterification reaction are distilled out of the system. The reaction time depends on the reaction temperature and the degree of pressure reduction, but is usually 1 to 4
It's about time. The reaction is preferably carried out in an atmosphere of an inert gas such as nitrogen or argon. Also, if desired,
The reaction may be carried out by adding an antioxidant or a branching agent.

Specific examples of the dihydric phenol derived from the general formula (B) used for producing the polycarbonate in the present invention include biphenol, bis (4-hydroxyphenyl) methane and bis (4-hydroxyphenyl). ) Ether, bis (4-hydroxyphenyl) sulfone, bis (4-hydroxyphenyl) sulfoxide, bis (4-
Hydroxyphenyl) sulfide, bis (4-hydroxyphenyl) ketone, 1,1-bis (4-hydroxyphenyl) ethane, 2,2-bis (4-hydroxyphenyl) propane (bisphenol A; BPA), 2, 2-
Bis (4-hydroxyphenyl) butane, 1,1-bis (4
-Hydroxyphenyl) cyclohexane (bispheno-
Z; BPZ), 1,1-bis (4-hydroxyphenyl)-
3,3,5-trimethylcyclohexane, 2,2-bis (4-hydroxy-3,5-dibromophenyl) propane, 2,2-bis (4-hydroxy-3,5-dichlorophenyl) propane,
2,2-bis (4-hydroxy-3-bromophenyl) propane, 2,2-bis (4-hydroxy-3-chlorophenyl) propane, 2,2-bis (4-hydroxy-3-methylphenyl) propane, 2,2-bis (4-hydroxy-3,5-dimethylphenyl) propane, 1,1-bis (4-hydroxyphenyl) -1-phenylethane, bis (4-hydroxyphenyl) diphenylmethane, α, ω-bis [2- (p-hydroxyphenyl) ethyl] polydimethylsiloxane,
Examples include α, ω-bis [3- (o-hydroxyphenyl) propyl] polydimethylsiloxane. You may use these in combination of 2 or more types. Of these, it is particularly preferable to select from 2,2-bis (4-hydroxyphenyl) propane.

On the other hand, examples of the carbonic acid ester forming compound include phosgene, diphenyl carbonate, and di-
Examples thereof include bisallyl carbonates such as p-tolyl carbonate, phenyl-p-tolyl carbonate, di-p-chlorophenyl carbonate, and dinaphthyl carbonate. It is also possible to use two or more of these compounds in combination.

Specific examples of the fluorene-containing dihydric phenol for deriving the general formula (A) include compounds represented by the following structural formulas.

[0024]

[Chemical 7]

[0025] These sac Chi 9, 9- bis (4-hydroxy-3-methylphenyl) fluorene, etc. 3,6-dimethyl-9,9-bis (4-hydroxyphenyl) fluorene is preferred. It is also possible to use two or more of the above dihydric phenols in combination.

The polycarbonate polymer synthesized by these reactions can be molded by known molding methods such as extrusion molding, injection molding, blow molding, compression molding and wet molding, but as a molding material for optical recording media. It is desirable that extrusion and injection molding can be carried out easily, and particularly in precision molding for optical recording media, the intrinsic viscosity is preferably in the range of 0.30 to 0.50 dl / g.

The fluorene structural unit of the general formula (A) of the present invention is preferably 5 mol% or more and less than 20 mol% in all structural units in consideration of moldability, heat resistance and low birefringence. 15 m to make the refraction more clear
It is preferably ol% or more and less than 20 mol% . If the fluorene structural unit is less than 5 mol%, the birefringence will be too large, and if it is less than 15 mol%, the birefringence will be considerably improved, but it is not always sufficient. 20 mol% or more
It happens when it tends to cause an increase in birefringence by the glass transition temperature molding conditions by increasing narrows molding defects and molecular orientation
It

In the fluorene structural unit represented by the above general formula (A), when R ₃ and R ₄ have substituents, the glass transition temperature of the polymer is lowered and the fluidity is improved without impairing the birefringence. Good moldability. Especially R ₃ and R ₄
However, an alkyl group having 1 to 5 carbon atoms, an alkoxy group and the like are preferable.

The polycarbonate molding material for an optical recording medium of the present invention must be highly purified like the polycarbonate for a general optical disk. Specifically, dust with a diameter of 50 μm or more is not substantially detected, dust with 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, residual hydroxyl group. It is purified so as to meet the criteria such as 200 ppm or less, residual nitrogen content of 5 ppm or less, and residual monomer of 20 ppm or less as much as possible. In addition, post-treatment such as extraction may be carried out to remove low molecular weight substances and solvents.

Polycarbonate molding materials for optical recording media are used in order to secure the stability and mold releasability required during extrusion and injection molding, and if necessary, hindered phenol-based or phosphite-based antioxidants; silicon-based, fatty acids Lubricants and mold release agents such as ester type, fatty acid type, fatty acid glyceride type, beeswax and other natural oils and fats; benzotriazole type, benzophenone type, dibenzoylmethane type, salicylate type light stabilizers; polyalkylene glycol, fatty acid glyceride, etc. An antistatic agent or the like may be appropriately used in combination, and further, it may be optionally mixed with a general polycarbonate for an optical recording medium within a range that does not impair the performance in view of cost and the like. The molding temperature for injection molding the present molding material is preferably 280 to 360 ° C. from the viewpoint of fluidity.

[0031]

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

Synthesis Example 1 2,2-bis (4-hydroxyphenyl) propane (BP was added to 60 liters of an aqueous solution of 8.8% (w / v) sodium hydroxide.
A) 6.38 kg (28 mol) and 9,9-bis (4-hydroxyphenyl) fluorene (BPFL) 4.20 kg (1
2 mol) and 50 g of hydrosulfite were added and dissolved. To this, 36 liters of methylene chloride was added and stirred, and 5 kg of phosgene was added to 6 while maintaining the solution temperature at 15 ° C.
It was blown in over 0 minutes. After the completion of blowing, 0.39 kg (2.6 mol) of pt-butylphenol was added and vigorously stirred to emulsify the reaction solution. After emulsification, 20 ml of triethylamine was added, and the mixture was stirred for about 1 hour for polymerization. The polymerization liquid is separated into an aqueous phase and an organic phase, the organic phase is neutralized with phosphoric acid, and after repeatedly washing with pure water until the pH of the washing liquid becomes neutral,
The organic phase was filtered with a 0.5 μm filter. 47 liters of isopropanol was added to the organic phase to precipitate the polymer. After filtering the precipitate, it was dried with a clean dryer to obtain a powdery polymer. This polymer had an intrinsic viscosity [η] of 0.35 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.

The results of the obtained above polymer was analyzed from the infrared absorption spectrum, absorption by a carbonyl group near 1770 cm ^-1, observed absorption by ether bond near 1240 cm ^-1, to have a carbonate bond was confirmed . Further, almost no absorption derived from a hydroxyl group was observed at a position of 3650 cm ^{-1 to} 3200 cm ^-1 . 172ppm of residual phenolic OH by absorptiometry
Met. As a result of monomer analysis by GPC, both BPA and BPFL were 20 ppm or less. As a result, this polymer is recognized as a polycarbonate polymer having the following structure.

[0034]

[Chemical 8]

Synthesis Example 2 Instead of BPFL in Synthesis Example 1, 9,9-bis (3-methyl-4-hydroxyphenyl) fluorene 4.54 kg (12 mol)
The same procedure as in Synthesis Example 1 was carried out except that was used. The intrinsic viscosity [η] of the obtained polymer is recognized as a polycarbonate polymer having the following structure by 0.36 dl / g infrared absorption spectrum analysis and the like.

[0036]

[Chemical 9]

Synthesis Example 3 0.345 kg (0.23 mol) of pt-butylphenol
) Was carried out in the same manner as in Synthesis Example 1 except that it was changed to). The intrinsic viscosity [η] of the obtained polymer was 0.43 dl / g, and it was confirmed by infrared absorption spectrum analysis and the like that it was the same polycarbonate polymer as in Synthesis Example 1 except for the degree of polymerization.

Synthesis Example 4 7.75 kg (34 mol) of BPA and 2.10 kg of BPFL
The same procedure as in Synthesis Example 1 was repeated except that the amount was changed to (6 mol). The intrinsic viscosity [η] of the obtained polymer was 0.34 dl / g, and it was confirmed by infrared absorption spectrum analysis and the like that it was the same polycarbonate polymer as in Synthesis Example 1 except for the polymerization ratio.

Synthesis Example 5 BPA 8.66 kg (38 mol), BPFL 0.70 kg
The same procedure as in Synthesis Example 1 was repeated except that the amount was changed to (2 mol). The intrinsic viscosity [η] of the obtained polymer was 0.36 dl / g, and it was confirmed by infrared absorption spectrum analysis and the like that it was the same polycarbonate polymer as in Synthesis Example 1 except for the polymerization ratio.

Synthesis Example 6 5.70 kg (25 mol) of BPA and 5.25 kg of BPFL
The same procedure as in Synthesis Example 1 was repeated except that the amount was changed to (15 mol).
The intrinsic viscosity [η] of the obtained polymer was 0.37 dl / g, and it was confirmed by infrared absorption spectrum analysis and the like that it was the same polycarbonate polymer as in Synthesis Example 1 except for the polymerization ratio.

Synthesis Example 7 Instead of BPFL of Synthesis Example 1, 3,6-dimethyl-9,9
-Bis (4-hydroxyphenyl) fluorene 4.5k
The same procedure as in Synthesis Example 1 was carried out except that g (12 mol) was used.
The intrinsic viscosity [η] of the obtained polymer was 0.37 dl / g,
From the infrared absorption spectrum analysis and the like, this polymer is recognized as a polycarbonate polymer having the following structure.

[0042]

[Chemical 10]

Synthesis Example 8 5.02 kg (22 mol) of BPA and 6.30 kg of BPFL
The same procedure as in Synthesis Example 1 was carried out except that the amount was changed to (18 mol).
The intrinsic viscosity [η] of the obtained polymer was 0.36 dl / g, and it was confirmed by infrared absorption spectrum analysis and the like that it was the same polycarbonate polymer as in Synthesis Example 1 except for the polymerization ratio.

Synthesis Example 9 The procedure was carried out except that BPA was changed to 9.12 kg (40 mol), BPFL was not used, and p-heptadecanylphenol was changed to 0.86 kg (2.6 mol) instead of pt-butylphenol. The procedure was as in Example 1. The intrinsic viscosity [η] of the obtained polymer was 0.37 dl / g, which was confirmed by infrared absorption spectrum analysis to be a polycarbonate polymer having the following structure.

[0045]

[Chemical 11] n represents the degree of polymerization. (N≈31)

Reference Example 1 Synthesis Example 1 Polycarbonate powder and commercially available beeswax 10
00 ppm was added, and the mixture was extruded at 290 ° C. with a vented 50 mm extruder equipped with a 50 μm polymer filter to perform melt pelletization. The obtained pellets are heated to a resin temperature of 350.
At 120 ° C, mold temperature of 100 ° C, injection pressure of 300 kg / cm2, a disk with an outer diameter of 120 mm and a thickness of 1.2 mm was injection molded, and the birefringence at 30 ° C oblique incidence was left after being left indoors for 2 days. It was measured. Further, the glass transition temperature (Tg) of the extruded pellets was measured and used as a measure of heat resistance.

Reference Examples 2 to 7 Using the polycarbonate powders of Synthesis Examples 2 to 7, injection molded articles were molded in the same manner as in Example 1 and tested in the same manner as in Example 1.

Comparative Example 1 Instead of the polycarbonate of Synthesis Example 1, a BPA type polycarbonate for a commercial optical recording medium (H-4000 manufactured by Mitsubishi Gas Chemical Co., Inc., [η] = 0.35 dl / g) was used. The same test was performed.

Comparative Example 2 Instead of the polycarbonate used in Synthesis Example 1, a commercially available polycarbonate-polystyrene copolymer for optical recording media (ODX manufactured by Mitsubishi Gas Chemical Co., Inc., [η] = 1.08 dl / g) was used. The same test as 1 was performed.

Comparative Example 3 Using the polycarbonate powder of Synthesis Example 9, the same test as in Example 1 was conducted.

Comparative Example 4 The same test as in Example 1 was conducted using the polycarbonate powder of Synthesis Example 8.

The test results of Reference Examples 1 to 7 and Comparative Examples 1 to 4 are shown in Table 1.

[0053]

[Table 1]

Birefringence: Using an automatic ellipsometer manufactured by Mizojiri Optical Co., Ltd. Measurement wavelength 632.8nm. Glass transition temperature: Measured by DSC manufactured by Shimadzu Corporation. FL concentration: ratio of the general formula (A) constitutional unit to all constitutional units (mol%)

[0055]

INDUSTRIAL APPLICABILITY The present invention can provide a molding material for an optical recording medium which has both excellent heat resistance and low birefringence, and in particular, a rewritable optical disk and magneto-optical recording which require high density recording and reliability. Suitable for discs.

─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Kazuyuki Akahori 5-6-2 Higashi-Hachiman, Hiratsuka-shi, Kanagawa Mitsubishi Engineering Plastics Co., Ltd. Hiratsuka Technical Center (56) Reference JP-A-6-145492 (JP) , A) JP-A-6-25399 (JP, A) JP-A-7-109342 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C08G 64/00-64/42

Claims (3)

(57) [Claims] 1. A constitutional unit represented by the following general formula (A) and a general formula (B) having a fluorene structure, wherein the constitutional unit of the general formula (A) is 5 mol% in all constitutional units.
And less than 20 mol% and an intrinsic viscosity of 0.30
A molding material for an optical recording medium, which is made of polycarbonate having a content of 0.50 dl / g. [Chemical 1] (In the formula, R _{1 to} R ₄ are each a hydrogen atom, a fluorine atom, a chlorine atom, a bromine atom, and an alkyl group having 1 to 5 carbon atoms, an aryl group having 6 to 12 carbon atoms, and a carbon number, each of which may have a substituent. 2-5
Are alkenyl groups having 1 to 5 carbon atoms, and aralkyl groups having 7 to 17 carbon atoms, and the substituents which may be present on any of the carbons of these groups are alkyl groups having 1 to 5 carbon atoms or An alkenyl group, an alkoxy group having 1 to 5 carbon atoms,
A halogen atom selected from fluorine, chlorine and bromine, and a dimethylpolysiloxy group. However, of R _{1 and} R ₂ ,
At least one is a group other than a hydrogen atom. ) [Chemical 2] (In the formula, R _{5 to} R ₈ are each hydrogen, fluorine, chlorine, bromine, iodine, and each of which may have a substituent, and has 1 carbon atom.
To an alkyl group having 5 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, and an aralkyl group having 7 to 17 carbon atoms. Substituents that may have any of these have 1 to 5 carbon atoms.
And an alkenyl group, an alkoxy group having 1 to 5 carbon atoms, a halogen selected from fluorine, chlorine, bromine and iodine, and a dimethylpolysiloxy group. X is one of the groups shown below. [Chemical 3] Here, R ₉ and R ₁₀ each represent hydrogen, an alkyl group having 1 to 5 carbon atoms which may have a substituent, an alkoxy group or an aryl group having 6 to 12 carbon atoms, or R ₉ and R ₁₀ Represent groups forming a carbocycle or a heterocycle when they are bonded together, and the substituents which may be present on the carbon atoms of these groups are alkyl or alkenyl groups having 1 to 5 carbon atoms, or 1 to 5 carbon atoms. 5
Is a halogen selected from an alkoxy group, fluorine, chlorine, bromine and iodine. a is an integer of 0 to 20, b and c
Represents an integer of 1 to 100. ) 2. The general formula (B) is a structural unit derived from 2,2-bis (4-hydroxyphenyl) propane, and the general formula (A) is 9,9-bis (4-hydroxy-3-methylphenyl). ) Fluorene, 3,6-dimethyl-9,9-
The molding material for an optical recording medium according to claim 1, which has a structural unit derived from the group consisting of bis (4-hydroxyphenyl) fluorene. 3. The structural unit of general formula (A) is in all structural units.
The molding material for an optical recording medium according to claim 1, which is 15 mol% or more and less than 20 mol% .