JPH11165342A - Manufacture of polycarbonate molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a method for reducing an amount of a chlorine compound in a molding by suppressing a thermal oxidation deterioration at the time of melt molding, of a polycarbonate copolymer. SOLUTION: At least 80 mol.% of a total aromatic dihydroxy component contains (a) 1,1-bis (4-hydrophenyl)-3,3,5-trimethylcyclohexane (component (a)) and (b) at least one type of aromatic dihydroxy component (component (b)) selected from 4,4'-(m-phenylenediisopropylidene) diphenol and 2,3-bis (3-methyl-4- hydroxyphenyl)propane. In this case, to extrusion mold powder particles of a polycarbonate copolymer having a ratio of the component (a) to the component (b) is 99:1 to 20:80 by a molar ratio, the particles are contained in a storage container having a gas supply port and exhaust port, gas in the container is sucked to be removed, then an inert gas is introduced and sealed to the particles from the supply port, inert gas treated, and then supplied to an extruder.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for producing a polycarbonate molded article. More specifically, the present invention relates to a method for producing a polycarbonate molded article which sufficiently suppresses thermal oxidation deterioration during melt molding, has good thermal stability, and is suitable for optical materials having a very small amount of chlorine compounds.

[0002]

BACKGROUND OF THE INVENTION At least 8 of the wholly aromatic dihydroxy components
0 mol% is (a) 1,1-bis (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane (component a) and (b) 4,4 '-(m-phenylenediisopropylidene) diphenol (Component b) and component a
The polycarbonate copolymer composed of the component (b) and the component (b) in a molar ratio of 99: 1 to 20:80 has excellent transparency, mechanical properties, moldability, heat stability and the like suitable for optical materials. And low birefringence (Japanese Patent Application Laid-Open Nos. 8-81549 and 8-293128). However, it has been revealed that when oxygen is mixed or coexistently adsorbed during melt molding of this polycarbonate copolymer, thermo-oxidative degradation is severely caused. Conventionally, when a bisphenol A-based polycarbonate powder is melt-molded by a vented extruder, a method of devolatilizing a substance that induces thermal oxidative deterioration such as oxygen from the vent and an inert gas filling method are known ( JP-A-60-184
813, JP-A-60-184814, JP-A-9-31208). However, even if this method was applied to the above polycarbonate copolymer, thermal oxidation deterioration could not be sufficiently suppressed and improved.

On the other hand, in a solution method most frequently used as a method for producing polycarbonate, a halogen-based organic solvent, particularly methylene chloride, is used as a solvent.
The polycarbonate is obtained as a solution in methylene chloride,
It is necessary to separate and remove methylene chloride from this solution.
However, since methylene chloride has a strong affinity for polycarbonate, it is extremely difficult to sufficiently separate and remove it. If a halogen-based compound such as methylene chloride is mixed in or coexisted with the polycarbonate copolymer during melt molding, thermal decomposition is likely to be induced. Further, when polycarbonate is used as an optical disk substrate, a residual solvent such as methylene chloride may adversely affect the optical disk such as corroding a metal film. Furthermore, in recent years, due to the growing problems of the environment and safety, regulations on the residual amount of methylene chloride in polycarbonate molded products have become strict. Particularly, according to US standards, the allowable amount of chlorine elution in water stored in polycarbonate bottles is 0.005 ppm or less. It is a very strict regulation. Conventionally, various methods have been proposed for facilitating desolvation of polycarbonate (Japanese Patent Application Laid-Open Nos. 1-149827 and 7-2602).
No. 4), but the solvent removal is insufficient in each case.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method capable of sufficiently suppressing the thermal oxidation deterioration of the above polycarbonate copolymer during melt molding and reducing the amount of chlorine compounds in the molded product. To provide.

The inventor of the present invention has conducted intensive studies on the melt molding of the polycarbonate copolymer in order to achieve the above object. The body is stored in a storage container provided with a gas inlet and an exhaust port, and the gas in the storage container is suctioned and removed from the exhaust port. By replacing at least a part of the air contained in the granular material in the container with an inert gas and then supplying the air to the extruder, thermal oxidation deterioration during melt molding is significantly suppressed, and the thermal stability is reduced. Good,
In addition, it has been found that a polycarbonate molded article having an extremely small amount of a chlorine compound can be obtained.

[0006] Further studies based on this finding show that the powders subjected to the inert gas replacement treatment in the storage container are supplied to an extruder, and the powders and granules are present in a non-melting zone in the extruder. In the meantime, an inert gas is injected and devolatilized, while the polycarbonate copolymer is present in the melting zone in the extruder, water is injected and added, and the above effect is further enhanced by devolatilization. That is, the present invention has been completed.

[0007]

According to the present invention, at least 80 mol% of the wholly aromatic dihydroxy component contains (a) 1,1-
Bis (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane (component a) and (b) 4,4'-
At least one aromatic dihydroxy component (component b) selected from (m-phenylenediisopropylidene) diphenol and 2,2-bis (3-methyl-4-hydroxyphenyl) propane, and component a and component a In molding the granules of the polycarbonate copolymer having a molar ratio of 99: 1 to 20:80 by an extruder, the granules are provided with a gas supply port and an exhaust port. After the gas in the storage container is suctioned and removed from the exhaust port, an inert gas is sealed from the gas supply port with respect to the granular material, and an inert gas treatment is performed. And a method for producing a polycarbonate molded product.

[0008] The storage container of the granular material of the polycarbonate copolymer used in the present invention is provided with a gas supply port and an exhaust port. The gas supply port is preferably provided with a pressure adjusting valve for adjusting the pressure of the supply gas, and the exhaust port is preferably provided with a vacuum pump for suction and devolatilization. There is no particular limitation on the shape, material, thickness, and size of the storage container, and there is no particular problem as long as the storage container can withstand the suction devolatilization process and the gas sealing process. The volume is preferably up to about 50 times the exhaust capacity of the vacuum pump from the viewpoint of the efficiency of suction and devolatilization, and more preferably 0.3 to ³ m ³ .

[0009] The suction devolatilization process in the storage container is a process for removing air and chlorine compounds contained in the granular material in the storage container, and is usually performed by a vacuum pump connected to an exhaust port. The suction force is preferably set to a degree of vacuum of 50 Torr or less, and particularly preferably set to a degree of vacuum of 10 Torr or less. The suction time is maintained at a predetermined degree of vacuum, usually 1 minute or more, preferably about 5 minutes.

In the gas filling process performed after the suction devolatilization process, a gas inert to the granules of the polycarbonate copolymer is filled from the gas supply port, and the inside of the storage container is subjected to normal pressure or slight pressurization. It is preferable to make it into a state.
A pressure of about one atmosphere is desirable. This encapsulation rate of the inert gas need not be particularly limited, but from the perspective of holding the particle size of the powder particles, at least 0.05-1 M ³ / min is preferably about. The series of operations of the suction devolatilization process and the gas filling process in this storage container is at least once, preferably 2 to 5 times,
More preferably, it is repeated about 3 to 5 times.

In addition, as a processing method for continuously performing the suction devolatilization process and the gas filling process, the powdery granules are transferred to a storage container provided with a gas supply port, an exhaust port, and a device capable of continuous quantitative discharge. Here, the suction devolatilization process can be continuously performed by performing sequence control using a rotary valve.

After the suction devolatilization process and the gas filling process in the storage container are completed, it is preferable to keep the inert gas sealed state until the granular material in the storage container is subjected to the extrusion step. It is preferable to supply an inert gas. The gas used for the encapsulation treatment may be any gas that is inert to the powder of the polycarbonate copolymer. For example, nitrogen gas, carbon dioxide gas, a rare gas, or the like is used, and nitrogen gas is particularly preferably used. Further, it is preferable to use the filter after cleaning with a filter having an opening of about 0.5 to 0.1 μm from the viewpoint of preventing foreign matter from being mixed. In this way, by performing the suction devolatilization process and the gas filling process in the storage container, the air and chlorine compounds contained in the polycarbonate copolymer powder are replaced with the inert gas, and the extruder to be performed next is used. Thermal oxidative degradation during melt molding can be sufficiently suppressed and the amount of chlorine compounds in the resulting molded article can be reduced.

The extruder used in the present invention is preferably a twin-screw extruder having at least one vent in the non-melting zone and an injection port for the extruder in front of the vent. A gas inert to the granules is injected through at least one extruder inlet in the non-melting zone and devolatilized from the nearest vent behind the inlet. By doing so, it is possible to further sufficiently suppress the thermal oxidation deterioration during melt molding in the extruder, and to further reduce the amount of the chlorine compound in the obtained molded article. The injection amount of the inert gas per one extruder injection port in the non-melting zone is 1 to 1 with respect to the space volume of the extruder.
The amount is preferably 00 times / min, and the devolatilizing suction force from the vent behind the vent is preferably 50 Torr or less, particularly preferably 10 Torr or less. By the devolatilization from the vent in the non-melting zone, a stable extrusion operation in which the oxygen-containing gas does not flow in and the granules are not discharged out of the extruder is maintained. Sufficient effects can be obtained by performing the injection of the inert gas in the non-melting zone and the devolatilization suction from the vent once. Here, the inert gas to be injected is the same as described above, and is preferably an inert gas that has been subjected to a cleaning treatment.

In addition, a twin-screw extruder provided with at least one vent and at least one extruder inlet immediately before the at least one vent in the melting zone is used. Water in an amount of 0.2 to 4 parts by weight per part by weight,
Inject and add from at least one extruder inlet and 50 Torr from the nearest vent behind this inlet.
When devolatilization is performed at a degree of vacuum of r or less, thermal oxidation deterioration during melt molding in an extruder can be more sufficiently suppressed, and the amount of chlorine compounds in the obtained molded product can be further reduced, which is preferable. . In particular, it is preferable to add and inject from two or three injection ports for the extruder, and to devolatilize each of the vents closest to each of the injection ports at a vacuum of 50 Torr or less. It is particularly preferable to perform the process at a degree of vacuum of 10 Torr or less.

In particular, using a twin-screw extruder, the inert gas is injected into the non-melting zone and devolatilized and suctioned from the vent. The combined use of devolatilization and suction from can further sufficiently suppress thermal oxidation deterioration during melt molding in an extruder, and can further sufficiently reduce the amount of chlorine compounds in the obtained molded article. It is preferred.

If the number of vents is too large, the length of the extruder becomes longer and adverse effects such as burning of resin are likely to occur. Therefore, the total number of vents is suitably about 3 to 5. In addition, it is preferable that the transport line between the storage container for the granular material of the polycarbonate copolymer used in the present invention and the extruder is filled with an inert gas.

The polycarbonates targeted in the present invention are:
As the constituent aromatic dihydroxy component, component a is 1,1-bis (4-hydroxyphenyl) -3,3,5
Trimethylcyclohexane and 4,4 'as component b
At least one aromatic dihydroxy component selected from-(m-phenylenediisopropylidene) diphenol and 2,2-bis (3-methyl-4-hydroxyphenyl) propane at least one of the wholly aromatic dihydroxy components; 80
It is advantageously at least 90 mol%, preferably at least 90 mol%, and typically it is desirable to be a polycarbonate copolymer substantially formed by components a and b. When the proportion of the component a and the component b is less than 80 mol%, the properties as an optical material are unsatisfactory, which is not preferable.

Component a and component b are in a molar ratio of 9
9: 1 to 20:80, and 80:20 to 20:
The range of 80 is preferable, and the range of 80:20 to 30:70 is more preferable. The proportion of component a is greater than 99 mol%,
When the proportion of the component b is less than 1 mol%, the resulting copolymer has poor melt fluidity and causes molding defects, and it is difficult to obtain optically good molded products. When the ratio of the component a is 20
If it is less than mol% and the proportion of the component b is more than 80 mol%, the photoelastic constant of the obtained copolymer tends to increase, and the glass transition temperature tends to decrease.

In the polycarbonate copolymer used in the present invention, it is desirable that the component a and the component b account for at least 80 mol%, preferably at least 90 mol% of the wholly aromatic dihydroxy component. 20% by mole of component c) per total aromatic dihydroxy component
Below, preferably 10 mol% or less may be contained. The component c may be any component other than the component a and the component b, which is usually used as a dihydroxy component of polycarbonate. Examples of the component c include hydroquinone, resorcinol, 4,4'-biphenol, and 1,1.
-Bis (4-hydroxyphenyl) ethane, 2,2-bis (4-hydroxyphenyl) propane, 2,2-bis (3-methyl-4-hydroxyphenyl) propane,
2,2-bis (4-hydroxyphenyl) butane, 1,
1-bis (4-hydroxyphenyl) -1-phenylethane, 1,1-bis (4-hydroxyphenyl) cyclohexane, 2,2-bis (4-hydroxyphenyl) pentane, 4,4 ′-(p-phenyl Diisopropylidene) diphenol, 9,9-bis (4-hydroxyphenyl) fluorene, 1,1-bis (4-hydroxyphenyl) -4-isopropylcyclohexane and the like. Among them, 2,2-bis (4 -Hydroxyphenyl)
Propane, 2,2-bis (3-methyl-4-hydroxyphenyl) propane and 9,9-bis (4-hydroxyphenyl) fluorene are preferred.

The polycarbonate copolymer has a 0.7%
g is dissolved in 100 ml of methylene chloride and the specific viscosity measured at 20 ° C. is preferably 0.2 to 0.5.
Those having a range of 5 to 0.4 are more preferable. Specific viscosity is 0.
If it is less than 2, the molded product will be brittle, and if it is more than 0.5, the melt fluidity will be poor, and molding failure will occur, and it will be difficult to obtain optically good molded products.

The polycarbonate copolymer used in the present invention preferably has a water absorption of 0.2% by weight or less, as measured by ASTM D-0570, and 0.18% by weight or less.
More preferably, the amount is not more than%. If the water absorption exceeds 0.2% by weight, the optical disk having a metal film formed on the surface of an optical disk substrate on which the polycarbonate copolymer of the present invention is suitably used is likely to be warped by water absorption, causing a tracking error. It is not preferable because it becomes easy to perform. Particularly preferred water absorption is 0.15% by weight or less.

The oligomer content of the polycarbonate copolymer used in the present invention is preferably 10% or less, more preferably 7% or less, and particularly preferably 5% or less. The value of the oligomer content is a value measured using the following method and column. That is, Tosoh Corporation, TS
Kgel G2000HXL and G3000HXL columns were connected in series one by one, and chloroform was used as an eluent. After stabilizing at a flow rate of 0.7 ml / min, a retention time of a GPC chart measured by a method of injecting a chloroform solution of a polycarbonate copolymer was used. Is the ratio of the total of the oligomer peak areas after 19 minutes to the total peak area is the oligomer content, and this value is preferably 10% or less, more preferably 7% or less. If the oligomer content exceeds 7%, especially 10%, the mold surface may be contaminated during molding, which is not preferable, and the contamination tends to become more pronounced as the oligomer content increases. On the other hand, the oligomer is generated during the production process of the polycarbonate copolymer and cannot be completely reduced to zero (0).

The content of the oligomer may be not more than the above-mentioned content, and as long as the value is satisfied, it may be contained in a small proportion. When the oligomer is present in a small content of 0.1% or more, more preferably 0.15% or more, the melt fluidity is improved as compared with the oligomer having a small content. Thus, a particularly preferred oligomer content is in the range of 0.15-4%.
In order to control the oligomer content in the polycarbonate copolymer within the above range, it is necessary to complete the polymerization sufficiently so that a large amount of the oligomer is not contained in the copolymer, and it is necessary to optimize the catalyst and the polymerization conditions. It is required to be elected. When the oligomer content exceeds the above range, a treatment for removing the oligomer by means such as extraction is adopted. This extraction is performed by dropping a solution of the polycarbonate copolymer (for example, a methylene chloride solution) into a poor solvent or a non-solvent (for example, acetone or methanol) of the copolymer, or converting the copolymer into a poor solvent or a non-solvent. It can be carried out by means such as a method of extracting the oligomer by immersion.

The polycarbonate copolymer is an optical material,
In particular, since it is suitably used as an optical disk substrate, it is preferable that undissolved particles do not exist in a certain amount or more. That is, 20 g of the polycarbonate copolymer
Is dissolved in 1 liter of methylene chloride, and a liquid particle counter model 4100 manufactured by Hiac Leuco is used.
The undissolved particles having a diameter of 0.5 μm or more determined by a method of converting scattered light into scattered light of latex particles by a laser sensor method using Preferably 25.0
The number is 00 or less, more preferably 15,000 or less, particularly preferably 10,000 or less. 1 μm
It is preferable that the number of the undissolved particles is 900 or less.
More than 00 are more preferable. Further, it is preferable that undissolved particles having a size of 10 μm or more do not substantially exist. These polycarbonate copolymers having a small number of undissolved particles are preferable because they do not adversely affect the information pits written on the optical disk and have a reduced error rate.

In order to keep the amount of undissolved particles in the polycarbonate copolymer within the above range, means should be employed that does not allow undissolved particles to be mixed in or removed during the polymerization process and the granulation process. Such means include, for example, performing the operation in a clean room, using a granulator equipped with a device for removing undissolved particles (for example, a kneader having an isolation chamber having a foreign substance take-out port in the bearing), or sliding. Granulation may be performed by an apparatus (for example, a spray dryer type granulator) having a structure in which the moving part does not come into contact with the resin particles. Further, as another means for removing undissolved particles, a resin solution is filtered with a small opening filter (0.5 to 0.5).
1 μm) or a method of melting the resin and then removing solid particles with a metal filter (10 to 40 μm).

The polycarbonate copolymer used in the present invention is produced by a reaction means known per se for producing ordinary polycarbonate, for example, a method of reacting an aromatic dihydroxy component with a carbonate precursor such as phosgene or carbonic acid diester. Next, basic means of these manufacturing methods will be briefly described. In a reaction using, for example, phosgene as a carbonate precursor, the reaction is usually performed in the presence of an acid binder and a solvent. As the acid binder, for example, an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide or an amine compound such as pyridine is used.
As the solvent, for example, a halogenated hydrocarbon such as methylene chloride or chlorobenzene is used. For promoting the reaction, a catalyst such as a tertiary amine or a quaternary ammonium salt can be used. At that time, the reaction temperature is usually 0 to
40 ° C. and the reaction time is a few minutes to 5 hours.

The transesterification reaction using a carbonic acid diester as a carbonate precursor is a method in which a predetermined ratio of an aromatic dihydroxy component is stirred with a carbonic acid diester while heating under an inert gas atmosphere to distill off the produced alcohol or phenol. It is performed by The reaction temperature varies depending on the boiling point of the alcohol or phenol to be formed, but is usually in the range of 120 to 300 ° C. The reaction is completed while distilling off alcohol or phenols produced by reducing the pressure from the beginning. Further, a catalyst usually used in a transesterification reaction to promote the reaction can also be used. Examples of the carbonic acid diester used in the transesterification reaction include diphenyl carbonate, dinaphthyl carbonate, bis (diphenyl) carbonate, dimethyl carbonate, diethyl carbonate, dibutyl carbonate and the like. Of these, diphenyl carbonate is particularly preferred.

The polycarbonate copolymer used in the present invention is prepared by using a mixture of the components a and b and, if necessary, the component c as the aromatic dihydroxy component, according to a known reaction for forming a polycarbonate. can do. In the polymerization reaction, monofunctional phenols generally used as a terminal terminator can be used. Particularly in the case of reactions using phosgene as the carbonate precursor, monofunctional phenols are commonly used for molecular weight control as end-stoppers, and the resulting polycarbonate copolymers are based on monofunctional phenols at the ends. Because it is blocked by a group, it has better thermal stability than that which is not. Such a monofunctional phenol may be any one used as a terminal terminator for polycarbonate, and is generally a phenol or a lower alkyl-substituted phenol, and can be a monofunctional phenol represented by the following general formula. .

[0029]

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Wherein A is a hydrogen atom or a group having 1 to 9 carbon atoms;
It is preferably 1 to 8 aliphatic hydrocarbon groups, and r is 1 to
5, preferably an integer of 1 to 3. ]

Specific examples of the monofunctional phenols include phenol, p-tert-butylphenol, p-cumylphenol and isooctylphenol.

Further, other monofunctional phenols include:
Phenols or benzoic acid chlorides having a long-chain alkyl group or aliphatic polyester group as a substituent, or long-chain alkyl carboxylic acid chlorides can be used, and the ends of the polycarbonate copolymer are blocked using these. Then, they not only function as a terminal terminator or a molecular weight regulator, but also improve the melt fluidity of the resin, facilitate not only the molding process, but also the physical properties as a substrate. Particularly, it has an effect of lowering the water absorption of the resin, and has an effect of reducing the birefringence of the substrate, and is preferably used. These are represented by the following general formulas [Ia] to [I
-H].

[0033]

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[0034]

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[0035]

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[0036]

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[0037]

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[0038]

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[0039]

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[0040]

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[Wherein X is -RO-, -R-CO-
O- or -RO-CO-, wherein R is a single bond or a divalent aliphatic hydrocarbon group having 1 to 10 carbon atoms, preferably 1 to 5 carbon atoms; And n is an integer of 10 to 50. Q is a halogen atom or a monovalent aliphatic hydrocarbon group having 1 to 10, preferably 1 to 5 carbon atoms, p is an integer of 0 to 4, and Y is 1 to 10 carbon atoms, preferably 1 to 5 is a divalent aliphatic hydrocarbon group, W ¹ is a hydrogen ^{atom, -CO-R 13, -CO-} O
—R ¹⁴ or R ¹⁵ , wherein R ¹³ , R ¹⁴ and R ¹⁵ are each a monovalent aliphatic hydrocarbon group having 1 to 10 carbon atoms, preferably 1 to 5 carbon atoms, and 4 to 8 carbon atoms, preferably 5 to 6 monovalent alicyclic hydrocarbon group or 6 to 15 carbon atoms, preferably 6 to 1
2 represents a monovalent aromatic hydrocarbon group. a is an integer of 4 to 20, preferably 5 to 10, m is an integer of 1 to 100, preferably 3 to 60, particularly preferably 4 to 50, Z is a single bond or a carbon number of 1 to 10, Preferably 1 to 5
W ² is a hydrogen atom, a monovalent aliphatic hydrocarbon group having 1 to 10 carbon atoms, preferably 1 to 5 carbon atoms, and a carbon atom having 4 to 8, preferably 5 to 6 carbon atoms. A monovalent alicyclic hydrocarbon group or a monovalent aromatic hydrocarbon group having 6 to 15, preferably 6 to 12 carbon atoms. ]

Of these, preferred are the substituted phenols [Ia] and [Ib]. This [Ia]
As the substituted phenols, n is 10 to 30, especially 1
Those having 0 to 26 are preferred, and specific examples thereof include decylphenol, dodecylphenol, tetradecylphenol, hexadecylphenol, octadecylphenol, eicosylphenol, docosylphenol and triacontylphenol.
Further, as the substituted phenols of [Ib], X is -R
-CO-O-, and a compound in which R is a single bond is suitable, and n is 10 to 30, particularly 10 to 26. Specific examples thereof include decyl hydroxybenzoate and hydroxy. Dodecyl benzoate, tetradecyl hydroxybenzoate, hexadecyl hydroxybenzoate,
Eicosyl hydroxybenzoate, docosyl hydroxybenzoate and triacontyl hydroxybenzoate. In the substituted phenols or substituted benzoyl chlorides represented by the general formulas [Ia] to [Ig], the position of the substituent is generally preferably the p-position or the o-position, and a mixture of both is preferable. The monofunctional phenols,
It is desirable to introduce at least 5 mol%, preferably at least 10 mol%, to all terminals of the obtained polycarbonate copolymer. Monofunctional phenols may be used alone or in combination of two or more. You may.

In the polycarbonate copolymer used in the present invention, when 1,1-bis (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane is at least 80 mol% of the total aromatic hydroxy component. In some cases, the flowability of the resin may be reduced, and therefore, it is preferable to use substituted phenols or substituted benzoic chlorides represented by the general formulas [Ia] to [Ig] as a terminal stopper.

As the polycarbonate copolymer, those having a photoelastic constant of 60 × 10 ⁻¹³ cm ² / dyn or less, preferably 50 × 10 ⁻¹³ cm ² / dyn or less are advantageously used. If the value of the photoelastic constant is larger than the above value, the material is not suitable as an optical material, particularly an optical disk.

The glass transition point of the polycarbonate copolymer is preferably 120 ° C. or higher, more preferably 130 ° C. or higher, even more preferably 145 ° C. or higher. When the glass transition point is low, the heat resistance as an optical material, particularly as a disk substrate, is insufficient.

In the polycarbonate copolymer used in the present invention, when phosgene is used as a carbonate precursor and a chlorinated solvent such as methylene chloride is used as a solvent,
Some chlorine compounds remain. If the content of this chlorine compound is large, the molding die is corroded, the thermal stability of the polycarbonate copolymer is reduced, and when used as an optical disc substrate, the metal film is undesirably corroded. . Therefore, the content of chlorine compounds is 10
It is recommended that it be less than or equal to 7 ppm, preferably less than or equal to 7 ppm, particularly preferably less than or equal to 5 ppm. Here, the content of the chlorine compound means a value obtained by measuring the polycarbonate copolymer by a combustion method using a total organic halogen analyzer TOX10 manufactured by Mitsubishi Chemical Corporation.

The polycarbonate copolymer used in the present invention may be blended with a phosphorus compound to improve the thermal stability of the polycarbonate copolymer and to prevent a decrease in molecular weight and hue during molding. The phosphorus compound is at least one phosphorus compound selected from the group consisting of phosphorous acid, phosphoric acid, phosphonous acid, phosphonic acid and esters thereof, and is preferably represented by the following general formula [1]:
~ [4]

[0048]

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[0049]

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[0050]

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[0051]

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[0052] At least one phosphorus compound selected from the group consisting of: Here, R ^{1 to} R ¹² each independently represent a hydrogen atom, methyl, ethyl, propyl, isopropyl,
C1-C20 alkyl groups such as butyl, isobutyl, tert-butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, dodecyl, hexadecyl, octadecyl, and C6 carbon atoms such as phenyl, tolyl, and naphthyl
Represents an aryl group having from 15 to 15 or an aralkyl group having 7 to 18 carbon atoms such as benzyl and phenethyl. When two alkyl groups are present in one compound, the two
The two alkyl groups may combine with each other to form a ring.

Examples of the phosphorus compound represented by the above formula [1] include triphenyl phosphite, trisnonylphenyl phosphite, tris (2,4-di-tert-
Butylphenyl) phosphite, tridecyl phosphite, trioctyl phosphite, trioctadecyl phosphite, didecyl monophenyl phosphite, dioctyl monophenyl phosphite, diisopropyl monophenyl phosphite, monobutyl diphenyl phosphite, monodecyl diphenyl phosphite Phyte, monooctyldiphenylphosphite, bis (2,6-di-tert
-Butyl-4-methylphenyl) pentaerythritol diphosphite, 2,2-methylenebis (4,6-di-
tert-butylphenyl) octyl phosphite, bis (nonylphenyl) pentaerythritol diphosphite, bis (2,4-di-tert-butylphenyl)
Examples include pentaerythritol diphosphite, distearylpentaerythritol diphosphite, and the like. Examples of the phosphorus compound represented by the above formula [2] include tributyl phosphate, trimethyl phosphate, triphenyl phosphate, triethyl phosphate, and diphenyl monoorthoxenyl. Phosphate, dibutyl phosphate, dioctyl phosphate, diisopropyl phosphate and the like can be mentioned, and as the phosphorus compound represented by the above formula [3], tetrakis (2,4-di-tert-butylphenyl) -4,4-diphenylenephosphonite and the like And the compound represented by the above formula [4] includes:
For example, dimethyl benzene phosphonate, diethyl benzene phosphonate, dipropyl benzene phosphonate and the like can be mentioned.

Among them, trisnonylphenyl phosphite, tris (2,4-di-tert-butylphenyl)
Phosphite, distearylpentaerythritol diphosphite, trimethyl phosphate, triethyl phosphate and dimethyl benzenephosphonate are preferably used. The amount of the phosphorus compound is preferably 0.0001 to 0.05% by weight, more preferably 0.0005 to 0.02% by weight, and more preferably 0.001 to 0.01% by weight based on the polycarbonate copolymer. Particularly preferred. When the amount is within this range, a polycarbonate copolymer having more excellent thermal stability can be obtained.

The polycarbonate copolymer used in the present invention may be blended with a generally known antioxidant for the purpose of preventing oxidation. Examples thereof include phenolic antioxidants, and specifically, for example, triethylene glycol-bis [3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate], 1,6 -Hexanediol-bis [3- (3,5
-Di-tert-butyl-4-hydroxyphenyl) propionate], pentaerythritol-tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], octadecyl-3-
(3,5-di-tert-butyl-4-hydroxyphenyl) propionate, 1,3,5-trimethyl-2,
4,6-tris (3,5-di-tert-butyl-4-
(Hydroxybenzyl) benzene, N, N-hexamethylenebis (3,5-di-tert-butyl-4-hydroxy-hydrocinnamide), 3,5-di-tert-butyl-4-hydroxy-benzylphosphonate-diethyl Ester, tris (3,5-di-tert-butyl-
4-hydroxybenzyl) isocyanurate, 3,9-
Bis {1,1-dimethyl-2- [β- (3-tert-
Butyl-4-hydroxy-5-methylphenyl) propionyloxy] ethyl} -2,4,8,10-tetraoxaspiro (5,5) undecane. The preferred compounding amount of these antioxidants is 0.0001 to 0.05% by weight based on the polycarbonate copolymer.

Further, higher fatty acid esters of monohydric or polyhydric alcohols can be added to the polycarbonate copolymer used in the present invention, if necessary. By blending the higher fatty acid ester of the monohydric or polyhydric alcohol, the mold releasability from the mold at the time of molding the polycarbonate copolymer is improved. Deformation of the disk substrate and pit shift due to a mold defect can be prevented. There is also an advantage that the melt fluidity of the polycarbonate copolymer is improved. The higher fatty acid ester is preferably a partial ester or a whole ester of a monohydric or polyhydric alcohol having 1 to 20 carbon atoms and a saturated fatty acid having 10 to 30 carbon atoms.

The partial or total ester of a monohydric or polyhydric alcohol and a saturated fatty acid includes monoglyceride stearic acid, monosorbitate stearate, monoglyceride behenic acid, pentaerythritol monostearate, pentaerythritol tetrastearate, Propylene glycol monostearate, stearyl stearate, palmityl palmitate, butyl stearate, methyl laurate, isopropyl palmitate, 2-ethylhexyl stearate, etc., among which stearic acid monoglyceride and pentaerythritol tetrastearate are preferred Used.
The amount of the ester of the alcohol and the higher fatty acid is 0.01 to 2% by weight, preferably 0.015 to 0.5% by weight, based on the polycarbonate copolymer.
0.02 to 0.2% by weight is more preferred. When the amount is within the above range, the releasability from the mold at the time of molding the polycarbonate copolymer is improved, and the mold surface is preferably free from stains.

Additives such as a light stabilizer, a colorant, an antistatic agent and a lubricant can be further added to the polycarbonate copolymer used in the present invention as long as the transparency is not impaired.
Further, other polycarbonates and thermoplastic resins can be added in a small proportion as long as the object of the present invention is not impaired.

[0059]

The present invention will be described below with reference to examples. In the examples, parts and% are parts by weight and% by weight, respectively.

(1) Specific viscosity: 0.7 g of polymer was added to 100
Dissolved in ml of methylene chloride and measured at 20 ° C.

(2) Undissolved particles of methylene chloride: A solution prepared by dissolving 20 g of polycarbonate in 1 liter of methylene chloride was scattered by latex particles by a laser sensor method using a liquid particle counter model 4100 manufactured by Haiac Leuco. Calculated by

(3) Total light transmittance: ASTM D-10
03, using Nippon Denshoku Sigma 80.

(4) Thermal stability (change in hue and specific viscosity): After drying the sample pellets at 120 ° C. for 5 hours,
Using an injection molding machine [SG-150 manufactured by Sumitomo Heavy Industries, Ltd.]
A test piece (70 mm long, 50 mm wide, 2 mm thick) which was or was not retained for 10 minutes at a cylinder temperature of 340 ° C.
mm) were prepared, and the change in specific viscosity (△ η _SP ) and the change in hue (△ E) were measured. Hue change is JIS
According to Z-8730, Nippon Denshoku Co., Ltd. model Z-100
Each L, a, b value was measured using 1DP and calculated by the following equation.

[0064]

(Equation 1)

(5) Chlorine compound content: Measured by a combustion method using a chlorine ion analyzer TSX10 manufactured by Mitsubishi Chemical Corporation.

Example 1 (A) 929.2 parts of ion-exchanged water and 61.3 parts of a 48% aqueous sodium hydroxide solution were charged into a reactor equipped with a thermometer, a stirrer and a reflux condenser. -Bis (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane (hereinafter sometimes abbreviated as "bisphenol TMC") 39 parts, 4,4 '-(m-phenylenediisopropylidene) diphenol After dissolving 43.6 parts and 0.17 part of hydrosulfite, 637.9 parts of methylene chloride are added, and 32.4 parts of phosgene are added under stirring at 15 to 20 ° C. 4
It took 0 minutes to blow. After injection of phosgene, p-te
1.51 parts of rt-butylphenol and 15.6 parts of a 48% aqueous sodium hydroxide solution were added, and the mixture was emulsified by stirring. After that, 0.09 parts of triethylamine was added, and the mixture was stirred at 28 to 33 ° C for 1 hour to complete the reaction. . After the completion of the reaction, the product solution was subjected to ion exchange water flow rate of 1,000 ml with a centrifugal extractor equipped with a perforated plate [Ultrex EP-02 manufactured by Hitachi, Ltd.].
/ Min, reaction product solution flow rate 1,500 ml / min, 3,5
After centrifugation at 00 rpm, the methylene chloride phase was acidified with hydrochloric acid, and the centrifugation operation was repeated under the same conditions. When the conductivity of the aqueous phase became almost the same as that of ion-exchanged water, foreign matter was collected on the bearing. The methylene chloride is evaporated by a kneader provided with an isolation chamber having an outlet to remove bisphenol T
MC and bisphenol M in a molar ratio of 50:50,
Powdery colorless polymer 7 having a specific viscosity of 0.283
5.7 parts (97% yield) were obtained.

(B) The powdery polymer was dried at 120 ° C. for 5 hours, transferred to a storage container, and subjected to a suction devolatilization treatment for 30 minutes while maintaining a vacuum of 6.6 Torr by a vacuum exhaust device. Nitrogen gas at a pressure of 2 kgf / cm ² , which was cleaned with a filter having an aperture of 0.2 μm, was press-filled and returned to normal pressure, and then maintained at normal pressure for 10 minutes while press-filling a small amount of nitrogen gas. Further, the suction devolatilization treatment and the nitrogen gas injection filling treatment were each performed alternately four times.
Then, the powdery granules were subjected to a 4-vent 46 mmφ twin-screw extruder (the vent closest to the raw material supply port was vent A, and the vents B to D were sequentially directed toward the extrusion port. Injection ports A to D for extruder
And Vent A and extruder inlet A are in the non-melting zone and the remaining vents BD and extruder inlets BD
Are all in the melting zone) at a rate of 40 kg / h. Nitrogen gas, which had been cleaned with a filter having an opening of 0.2 μm in the amount shown in Table 1 (liter / hour), was injected from the inlet A for the extruder, and then the non-melting gas attached after the inlet A for the extruder was injected. 0.003% of tris (nonylphenyl) phosphite and 0.005% of trimethyl phosphate to the polymer from the additive inlet in the zone
And stearic acid monoglyceride were added in an amount of 0.045%. Subsequently, ion-exchanged water of the amount (parts / 100 parts of polymer) shown in Table 1 was injected from the injection ports B to D for the extruder, and the degree of vacuum (Torr) shown in Table 1 was injected from the vents A to D.
The pellet was extruded under reduced pressure in r). Table 2 shows the evaluation results of the obtained pellets.

[Examples 2 to 6] In Example 1 (B), the number of times of performing the suction devolatilization processing and the nitrogen gas injection processing, the degree of vacuum at that time, the injection of nitrogen gas from the injection port A, the injection port B To D, and the pellets were obtained in the same manner as in Example 1 except that the amounts of ion-exchanged water to be injected and the degrees of vacuum of the vents A to D were changed as shown in Table 1. Table 2 shows the evaluation results of the obtained pellets.

[Comparative Example 1] The suction devolatilization process and the nitrogen gas injection process in the storage container in Example 1 (B) were not performed.
Also, without extruding nitrogen gas and injecting water in a twin-screw extruder with a multi-stage vent, the pellets were extruded from vents A to D at a reduced degree of vacuum (Torr) shown in Table 1 and pelletized. Table 2 shows the evaluation results of the obtained pellets.

[Comparative Example 2] The suction devolatilization process and the nitrogen gas injection process in the storage container in Example 1 (B) were not performed.
In addition, without injecting nitrogen gas into the twin-screw extruder with a multi-stage vent, ion-exchanged water was injected and added in the amounts shown in Table 1 from the extruder inlets B to D, and at the same time, vents A to D were used as shown in Table 1.
The pellets were extruded while being evacuated to a vacuum at the described degree of vacuum. Table 2 shows the evaluation results of the obtained pellets.

Example 7 (A) A reactor equipped with a thermometer, a stirrer and a reflux condenser was charged with 965.1 parts of ion-exchanged water and 63.6 parts of a 48% aqueous sodium hydroxide solution. -Bis (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane (bisphenol TMC) 24.3 parts, 2,2-bis (3-methyl-4-hydroxyphenyl) propane (hereinafter abbreviated as "bisphenol C") 46.
9 parts and 0.18 part of hydrosulfite were dissolved, and 662.5 parts of methylene chloride was added.
At 5 ° C., 32.4 parts of phosgene were blown in over 40 minutes.
After the injection of phosgene was completed, 2 parts of p-tert-butylphenol and 16.2 parts of a 48% aqueous sodium hydroxide solution were added, and the mixture was emulsified by stirring. Then, 0.09 part of triethylamine was added, followed by stirring at 28 to 33 ° C for 1 hour. To complete the reaction. After completion of the reaction, the product solution was diluted with methylene chloride, washed with water, acidified with hydrochloric acid, and washed with water. When the conductivity of the aqueous phase became almost the same as that of ion-exchanged water, the methylene chloride was evaporated to obtain bisphenol TMC and bisphenol C. Of the powdery and colorless polymer having a molar ratio of 30:70 and a specific viscosity of 0.295 (yield 97%). Pelletization was carried out using this powdery polymer in the same manner as in Example 1 (B). Table 2 shows the evaluation results of the obtained pellets.
It was shown to.

[0072]

[Table 1]

[0073]

[Table 2]

[0074]

According to the present invention, at least 80 mol% of the wholly aromatic dihydroxy component having excellent transparency, mechanical properties, moldability, thermal stability and the like and low birefringence is characterized. (A) 1,1-bis (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane (component a) and (b) 4,4 '-(m-phenylenediisopropylidene) diphenol (component b) And the component a and the component b have a molar ratio in the range of 99: 1 to 20:80, and sufficiently suppress the thermal oxidation deterioration during melt molding of the polycarbonate copolymer. This makes it possible to extremely reduce the amount of the chlorine compound, is suitably used as an optical disc substrate, and has an outstanding industrial effect.

Claims (12)

[Claims] 1. The method of claim 1, wherein at least 8 of the wholly aromatic dihydroxy components are present.
0% by mole of (a) 1,1-bis (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane (component a) and (b) 4,4 '-(m-phenylenediisopropylidene) di It comprises at least one aromatic dihydroxy component (component b) selected from phenol and 2,2-bis (3-methyl-4-hydroxyphenyl) propane, and the ratio of component a to component b is 99: 1 to 20:
In molding the granules of the polycarbonate copolymer constituted in the range of 80 by an extruder, the granules are stored in a storage vessel provided with a gas supply port and an exhaust port, and the inside of the storage vessel is discharged from the exhaust port. A method for producing a polycarbonate molded article, wherein an inert gas is sealed into the powder and granules from a gas supply port after the gas is removed by suction, the inert gas is treated, and then supplied to an extruder. . 2. A suction force for removing gas in a storage container,
2. The method for producing a polycarbonate molded product according to claim 1, wherein the degree of vacuum is 50 Torr or less. 3. The amount of the inert gas sealed in the storage container is
The method for producing a polycarbonate molded product according to claim 1 or 2, wherein the amount is such that the pressure in the storage container is maintained at least at normal pressure. 4. The method for producing a polycarbonate molded article according to claim 1, wherein the suction removal of the gas and the filling of the inert gas in the storage container are alternately repeated at least twice each. 5. An extruder having at least one vent in a non-melting zone and an extruder inlet provided in front of the vent, wherein an inert gas is supplied to the supplied granular material. Is press-fitted from at least one extruder inlet in the non-melting zone and devolatilized from the vent nearest the inlet. Production method. 6. The method according to claim 5, wherein the extruder is a twin-screw extruder. 7. The extruder according to claim 5, wherein the amount of inert gas injected per extruder injection port in the non-melting zone of the extruder is 1 to 100 times / min with respect to the space volume of the extruder.
A method for producing the polycarbonate molded article according to the above. 8. The method for producing a polycarbonate molded product according to claim 5, wherein a devolatilizing suction force from a vent in a non-melting zone of the extruder has a degree of vacuum of 50 Torr or less. 9. An extruder in which at least one vent is provided in the melting zone and an extruder inlet is provided in front of the at least one vent, and the extruder is used per 100 parts by weight of the supplied granular material. An amount of 0.2 to 4 parts by weight of water is injected from at least one extruder inlet and devolatilized at a degree of vacuum of 50 Torr or less from a vent closest to the inlet. A method for producing a molded polycarbonate article according to any one of claims 1 to 8. 10. An extruder in which at least two vents are provided in the melting zone and an extruder inlet is provided in front of the at least two vents as an extruder.
0.2 to 4 parts by weight of water per part by weight is injected from each of the at least two extruder inlets and 50 Torr from the nearest vent after each inlet.
The method for producing a polycarbonate molded article according to any one of claims 1 to 8, wherein devolatilization is performed at the following degree of vacuum. 11. The molecular weight of the polycarbonate copolymer is as follows:
The production of a polycarbonate molded article according to any one of claims 1 to 10, wherein the specific viscosity measured at 20 ° C of a solution obtained by dissolving 0.7 g thereof in 100 ml of methylene chloride is in the range of 0.2 to 0.5. Method. 12. The undissolved particles measured in a methylene chloride solution of a polycarbonate copolymer have a particle-converted diameter of 0.5 μm or more per 40 g of a polycarbonate copolymer and 40,000 or less. Any one of
The method for producing a polycarbonate molded article according to the above item.