JP2002037878A - Method of producing aromatic polycarbonate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an industrial method of producing an aromatic polycarbonate by melt polycondensing process having excellent color and less discoloration and molecular weight degradation even at a high temperature exceeding 380 deg.C. SOLUTION: The method of producing an aromatic polycarbonate comprises polymerization in melt state of an aromatic dihydroxy compound and a diaryl carbonate, wherein the diaryl carbonate contains (1) 200 wt.ppm or less of water, (b) 1 wt.ppm or less of aluminum and (c) 1 wt.ppm or less of p- phenoxyphenyl phenyl carbonate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for producing an aromatic polycarbonate.

[0002]

2. Description of the Related Art In recent years, aromatic polycarbonates have been widely used in many fields as engineering plastics having excellent heat resistance, impact resistance and transparency. However, polycarbonates produced by the conventionally used phosgene method use toxic phosgene at the time of production and contain residual methylene chloride which affects the heat stability of the polycarbonate and mold corrosion during molding. In recent years, transesterification polycarbonate has been reviewed.

Since the transesterification polycarbonate generally has a poor color, it has long been required to improve the coloring. However, if the color at the time of polycarbonate production is only good, it cannot be said that the quality as a molding material is satisfied, and among polycarbonates, aromatic polycarbonate is inferior in molding fluidity, so a good molded appearance is required. In the use as a molding material for injection molding and the use as a molding material for a molded article requiring high transparency, molding is generally carried out at a higher temperature than ordinary resins.

In recent years, applications as molding materials for precision molded articles requiring particularly high transferability have been expanding, and aromatic polycarbonates with little coloring even when molded at a high temperature have been strongly desired. In optical disc applications that require high cycleability of molding, molding is performed particularly at high temperatures, so there were problems such as resin coloring and molecular weight reduction during molding interruption such as mold cleaning. . That is, 38
Even at a high temperature of 0 ° C. or higher, there has been a strong demand for an aromatic polycarbonate which is less colored and has a smaller decrease in molecular weight.

When an aromatic polycarbonate is produced by polymerization in a molten state from an aromatic dihydroxy compound and a diaryl carbonate by a transesterification method, the amount of a specific compound present in a raw material is specified from the viewpoint of improving the coloring of the product. Many applications have been filed. For example, Japanese Patent Application Laid-Open No. 5-262
No. 872 discloses that a chlorine content based on chloroformate is 30 pp as an impurity contained in carbonic acid diester.
m or less, JP-A-6-179744 discloses that phenyl salicylate, o-phenoxybenzoic acid and phenyl o-phenoxybenzoate are not substantially contained as a carbonic acid diester. Use of a diaryl carbonate having a benzophenone derivative content of 100 ppm or less;
In JP 2074, diaryl carbonate having an ester derivative of 100 ppm or less is used. In JP-A-8-59815, diphenyl carbonate containing substantially no phenyl o-methoxybenzoate and xanthone is used. In the publication, the abundance of a specific compound in the diaryl carbonate is defined, for example, using a carbonic acid diester that does not contain any of a salicylic acid derivative, a tin ion, and methylphenyl carbonate. Also, JP-A-8-10474
No. 7, the aromatic dihydroxy compound having a specific structure has an abundance of 10 wt ppm or more and 3 wt% or less;
JP-A-8-104748 discloses that the total content of a specific bisphenol A derivative, a bisphenol A isomer, a chroman organic compound, and trisphenol I is 100 pp.
The use of bisphenol A having a content of not less than 200 ppm and not more than 200 ppm and an iron content of not more than 0.1 ppm is disclosed in JP-A-11-310630.
The amount of a specific compound in an aromatic dihydroxy compound is specified, for example, by using

[0006] However, these inventions are not always sufficient for improving the color, and have failed to provide an aromatic polycarbonate which has little coloring even at a high temperature of 380 ° C or higher and has a small decrease in molecular weight.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide an aromatic polycarbonate produced by a melt polycondensation method, which has a good color, has little coloring even at a high temperature of 380 ° C. or higher, and has a small molecular weight. It is an object of the present invention to provide an industrially preferable production method of a suitable aromatic polycarbonate.

[0008]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, when producing an aromatic polycarbonate, the content of a specific component in diaryl carbonate was adjusted to a specific range. It has been found that the above object can be achieved by controlling the temperature, and the present invention has been completed.

That is, the present invention provides: (1) A method for producing an aromatic polycarbonate by polymerizing an aromatic dihydroxy compound and a diaryl carbonate in a molten state, wherein (a) the water content in the diaryl carbonate is 200 ppm by weight or less. And (b)
(C) an aluminum content of 1 ppm by weight or less;
A process for producing an aromatic polycarbonate, wherein the content of (p-phenoxyphenyl) (phenyl) carbonate is 1 ppm by weight or less;

(2) The diaryl carbonate is
(A) a water content of 200 ppm by weight or less;
(1) The fragrance according to (1), wherein the diaryl carbonate having an aluminum content of 1 ppm by weight or less is a diaryl carbonate stored in a stainless steel container in a molten state at a temperature of 80 to 190 ° C under a nitrogen atmosphere. (3) The method for producing an aromatic polycarbonate according to (2), wherein the container made of stainless steel is a container in which a liquid contact portion on an inner wall surface is subjected to a washing treatment with phenol.

In the production of an aromatic polycarbonate by a melt polymerization method, usually, the raw material diaryl carbonate is not completely 100% pure but is derived from the method for producing the diaryl carbonate or the method for storing the produced diaryl carbonate. Contains various compounds. Diaryl carbonate is rarely used immediately after production, and is used after transportation and storage, so clarifying the effects of compounds that are mixed or generated during storage is an industrial process for producing aromatic polycarbonates. Is particularly important in doing so.

As a result of diligent studies by the present inventors, water mixed by moisture absorption, aluminum which is a catalyst component used for producing diaryl carbonate, and diaryl carbonate formed when stored in a molten state (p-phenoxy) Surprisingly, by making the content of phenyl) (phenyl) carbonate below the specified value, the color of the aromatic polycarbonate product is improved, and the coloring and the molecular weight reduction at a high temperature of 380 ° C. or more are reduced. It has been found that the stability is significantly improved.

Hereinafter, the present invention will be described in detail. In the present invention, the aromatic dihydroxy compound is HO-
It is a compound represented by Ar-OH (wherein, Ar represents a divalent aromatic group). The aromatic group Ar is preferably, for example, -Ar ¹ -Y-Ar ^2- (wherein Ar ¹ and Ar
² independently represents a divalent carbocyclic or heterocyclic aromatic group having 5 to 70 carbon atoms, and Y represents 1 carbon atom.
Represents a divalent alkane group having ３０30. ) Is a divalent aromatic group.

In the divalent aromatic groups Ar ¹ and Ar ² , at least one hydrogen atom has another substituent which does not adversely affect the reaction, for example, a halogen atom, an alkyl group having 1 to 10 carbon atoms, It may be substituted by an alkoxy group, a phenyl group, a phenoxy group, a vinyl group, a cyano group, an ester group, an amide group, a nitro group or the like represented by Formulas 1 to 10. Preferable specific examples of the heterocyclic aromatic group include an aromatic group having one or more ring-forming nitrogen, oxygen or sulfur atoms.

The divalent aromatic groups Ar ¹ and Ar ² represent, for example, substituted or unsubstituted phenylene, substituted or unsubstituted biphenylene, and substituted or unsubstituted pyridylene. The substituent here is as described above. The divalent alkane group Y is, for example, an organic group represented by the following chemical formula 1.

[0016]

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(Wherein R ¹ , R ² , R ³ and R ⁴ each independently represent hydrogen, an alkyl group having 1 to 10 carbon atoms,
A cycloalkyl group having 5 to 10 ring carbon atoms, a carbocyclic aromatic group having 5 to 10 ring carbon atoms, and a carbocyclic aralkyl group having 6 to 10 carbon atoms. k is 3 to 1
Represents an integer of 1, R ⁵ and R ⁶ are individually selected for each X, and independently represent hydrogen or an alkyl group having 1 to 6 carbon atoms, and X represents carbon. R ¹ , R ² , R
^{In 3} , R ⁴ , R ⁵ and R ⁶ , other substituents such as a halogen atom, an alkyl group having 1 to 10 carbon atoms and 1 to 10 carbon atoms are used as long as one or more hydrogen atoms do not adversely affect the reaction.
May be substituted by an alkoxy group, phenyl group, phenoxy group, vinyl group, cyano group, ester group, amide group, nitro group or the like. Examples of such a divalent aromatic group Ar include those represented by the following chemical formula 2.

[0018]

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(Wherein R ⁷ and R ⁸ each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, and a cycloalkyl having 5 to 10 ring carbon atoms) An alkyl group or a phenyl group, m and n
Is an integer of 1 to 4, and when m is 2 to 4, each R ⁷ may be the same or different, and n is 2 to 4
In this case, each R ⁸ may be the same or different. In addition, the divalent aromatic group Ar is represented by -Ar ¹ -Z-Ar ^2-
May be indicated.

Wherein Ar ¹ and Ar ² are as described above,
Is a single bond or -O -, - CO -, - S -, - SO 2 -,
-SO -, - COO -, - CON (R 1) - represents a divalent group, such as. Here, R ¹ is as described above. Examples of such a divalent aromatic group Ar include those represented by the following chemical formula (3).

[0021]

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(Wherein R ⁷ , R ⁸ , m and n are as described above.) Further, specific examples of the divalent aromatic group Ar include a substituted or unsubstituted phenylene, a substituted or unsubstituted phenylene. Examples include substituted naphthylene, substituted or unsubstituted pyridylene, and the like. The aromatic dihydroxy compound used in the present invention may be a single kind or two or more kinds. A typical example of the aromatic dihydroxy compound is bisphenol A. The diaryl carbonate used in the present invention is
It is represented by the following formula 4.

[0023]

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(Wherein, Ar^Three, Ar^FourAre monovalent
Represents an aromatic group. ) Ar^ThreeAnd Ar^FourIs a monovalent carbocyclic or heterocyclic aromatic
Represents an Ar group ^Three, Ar^FourIn one or more water
Other substituents whose elemental atoms do not adversely affect the reaction, for example
For example, a halogen atom, an alkyl group having 1 to 10 carbon atoms,
Alkoxy groups of the formulas 1 to 10, phenyl groups, phenoxy
Group, vinyl group, cyano group, ester group, amide group, nitro
It may be substituted by a group such as b. Ar^Three
And Ar^FourCan be the same or different
May be.

Representative examples of the monovalent aromatic groups Ar ³ and Ar ⁴ include a phenyl group, a naphthyl group, a biphenyl group and a pyridyl group. These may be substituted with one or more substituents described above. Preferred examples of Ar ³ and Ar ⁴ include, for example, those shown in Chemical Formula 5 below.

[0026]

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Representative examples of diaryl carbonates include substituted or unsubstituted diphenyl carbonates represented by the following formula (6).

[0028]

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(Wherein R ⁹ and R ¹⁰ are each independently a hydrogen atom, an alkyl group having 1 to 10 carbon atoms,
An alkoxy group having 10; a cycloalkyl group having 5 to 10 ring carbon atoms; or a phenyl group;
When p is 2 or more, each R ⁹ may be different, and when q is 2 or more,
Each R ¹⁰ may be different. Among these diphenyl carbonates, unsubstituted diphenyl carbonate, ditolyl carbonate, di-t
Symmetric diaryl carbonates such as lower alkyl-substituted diphenyl carbonates such as -butylphenyl carbonate are preferred, but unsubstituted diphenyl carbonate, which is a diaryl carbonate having the simplest structure, is particularly preferred.

These diaryl carbonates may be used alone or in combination of two or more. In the present invention, the water content of the diaryl carbonate is 200 ppm by weight or less. Moisture is 200 weight p
When it is more than pm, the color of the product aromatic polycarbonate deteriorates, and it becomes easy to color at a high temperature of 380 ° C. or higher, and the molecular weight is greatly reduced. Although the reason is not clear, it is presumed that a combination of decomposition of the diaryl carbonate due to the presence of water and an isomerization reaction of the diaryl carbonate adversely affects the stability of the aromatic polycarbonate at high temperatures. The water in the diaryl carbonate is preferably
pm or less, more preferably 50 ppm by weight or less.
The lower limit of the water content is not particularly limited, and may be lower than 0.01 ppm by weight.
Even if the amount is less than 1 ppm by weight, the effect of improving the coloring and the molecular weight reduction of the aromatic polycarbonate at a high temperature is small.

As a method for controlling the amount of water in the diaryl carbonate to the above range, there are a method of avoiding moisture absorption during transportation and storage, and a method of absorbing moisture so that the upper limit is 200% by weight.
When the water content becomes higher than pm, a method of performing a dehydration operation by distillation or the like and then using it for polymerization of an aromatic polycarbonate may, for example, be mentioned. In the present invention, the aluminum content in the diaryl carbonate is 1 ppm by weight.
It is as follows. When the aluminum content is more than 1 ppm by weight, the color of the resulting aromatic polycarbonate deteriorates, and the product tends to be colored at a high temperature of 380 ° C. or higher, and the molecular weight is greatly reduced.

Although the reason for this is not clear, it is assumed that the presence of aluminum acts catalytically on the coloring reaction and the molecular weight reduction reaction of the aromatic polycarbonate at high temperatures. The aluminum content in the diaryl carbonate is preferably 0.5 ppm by weight or less, more preferably 0.1 ppm by weight or less. There is no particular lower limit on the aluminum content.
The aluminum content may be less than m, but if the aluminum content is less than 0.001 weight ppm, the effect of improving the coloring and the molecular weight reduction of the aromatic polycarbonate at high temperatures is small.

As a method for controlling the aluminum content within the above range, when producing a diaryl carbonate, an aluminum catalyst is not used at all, or after a diaryl carbonate is produced using an aluminum catalyst, the aluminum is subjected to a distillation operation, a washing operation, or the like. A method of reducing the content and the like can be mentioned. However, when producing a diaryl carbonate without using an aluminum catalyst at all, it is preferable that other catalyst components that deteriorate the quality of the product polycarbonate are not contained in the diaryl carbonate.

In the present invention, the content of (p-phenoxyphenyl) (phenyl) carbonate in the diaryl carbonate is 1 ppm by weight or less. (P-phenoxyphenyl) (phenyl) carbonate content is 1 weight p
If it is higher than pm, the color of the product aromatic polycarbonate deteriorates, and it becomes easy to color at a high temperature of 380 ° C or higher.

Although the reason for this is not clear,
(P-phenoxyphenyl) (phenyl) carbonate itself or (p-phenoxyphenyl) (phenyl)
It is presumed that the reaction product of the carbonate and the aromatic polycarbonate tends to be colored at high temperatures. The content of (p-phenoxyphenyl) (phenyl) carbonate in the diaryl carbonate is preferably 0.5 ppm by weight or less, more preferably 0.1 ppm by weight or less. The lower limit of the content of (p-phenoxyphenyl) (phenyl) carbonate is not particularly limited, and is 0.01 wt.
The content of (p-phenoxyphenyl) (phenyl) carbonate may be less than m, but from 0.01 ppm by weight of (p-phenoxyphenyl) (phenyl)
Even if the carbonate content is reduced, the effect of improving the coloring of the aromatic polycarbonate at high temperatures is small.

In producing an aromatic polycarbonate from an aromatic dihydroxy compound and a diaryl carbonate,
In order to be industrially preferred and to handle the diaryl carbonate, the diaryl carbonate is usually used after being stored in a molten state. In the present invention, the diaryl carbonate is preferably stored in a stainless steel container in a molten state at a temperature of 80 to 190 ° C. in a nitrogen atmosphere. When the storage container is made of carbon steel, (p-phenoxyphenyl)
The amount of (phenyl) carbonate produced may increase. Stainless steel is defined as a stainless steel handbook, pp. 13-21 (published by Nikkan Kogyo Shimbun, 5th edition), and contains 10 to 30% by weight of normal chromium as classified and classified as martensitic, ferritic, and austenitic. , Ferrite
Examples include austenitic stainless steel and the like, and Fe-based superalloys as shown in the table on page 547 of the Stainless Steel Handbook. Specific examples include SUS201, SUS2
02, SUS304, SUS304L, SUS316,
SUS316L, SUS347, SUS405, SUS
430, SUS403, SUS410, SUS431,
SUS440C, SUS630, Incoloy 800, Incoloy 801, Incoloy 802, Incoloy 80
7, Incoloy 901, LCN155, W545, V5
7, W545, D979, CG27, S590 and the like. Preferred specific examples are SUS304, SUS
304L, SUS316, SUS316L and the like, particularly preferably SUS304.

The liquid contact portion on the inner wall surface of the stainless steel container is preferably subjected to a washing treatment with phenol. When a stainless steel container washed with phenol is used, the amount of (p-phenoxyphenyl) (phenyl) carbonate produced can be particularly reduced. Although the reason for this is not clear, it is presumed that removal of oxygen adsorbed on the stainless steel surface with phenol prevents formation of (p-phenoxyphenyl) (phenyl) carbonate.

The storage is preferably carried out under a nitrogen atmosphere. When air is mixed in the storage container, the amount of (p-phenoxyphenyl) (phenyl) carbonate increases. The storage temperature is preferably in the range of 80 to 190 ° C., and if it is higher than 190 ° C., the amount of (p-phenoxyphenyl) (phenyl) carbonate formed tends to increase. If the temperature is lower than 80 ° C., it is not preferable because solidification occurs depending on the type of diaryl carbonate. A more preferred storage temperature range is from 85 to 160C, more preferably from 90 to 140C.

In the production of the aromatic polycarbonate in the present invention, the ratio of the aromatic dihydroxy compound and the diaryl carbonate to be used (the charge ratio) depends on the kind of the aromatic dihydroxy compound and the diaryl carbonate to be used, the polymerization temperature and other polymerization conditions. The diaryl carbonate is usually 0.9 to 2.5 mol, preferably 0.1 mol, per 1 mol of the aromatic dihydroxy compound.
It is used in a proportion of 95 to 2.0 mol, more preferably 0.98 to 1.5 mol.

The number average molecular weight of the aromatic polycarbonate obtained by the method of the present invention is usually 5,000 to 100,000.
And preferably in the range of 5,000 to 30,000. The method for producing the aromatic polycarbonate of the present invention comprises:
From the aromatic dihydroxy compound and diaryl carbonate as described above, a polycondensation is carried out by transesterification in a molten state while heating under reduced pressure and / or inert gas flow in the presence or absence of a catalyst. There is no particular limitation on the polymerization vessel. For example, a stirred tank reactor, a thin film reactor, a centrifugal thin film evaporation reactor, a surface-renewal twin-screw kneading reactor, a twin-screw horizontal stirring reactor, a wet-wall reactor, and a perforated plate that allows free-fall polymerization A reactor, a perforated plate reactor with a wire, which polymerizes while being dropped along a wire, or the like, is used alone or in combination. The polymerization can be performed either in a batch system or a continuous system. It is also preferable to use an extruder, a polymer mixer, or the like in combination with a polymerizer as a device for adding a stabilizer, an additive, and the like while the aromatic polycarbonate is in a molten state after the polymerization. The material of these polymerization vessels is not particularly limited, and is usually selected from stainless steel, nickel, glass lining and the like.

In the present invention, in producing the aromatic polycarbonate by reacting the aromatic dihydroxy compound with the diaryl carbonate, the reaction temperature is usually selected from the range of 50 to 350 ° C., preferably 100 to 300 ° C. It is. As the reaction proceeds, an aromatic monohydroxy compound is produced, and by removing this compound from the reaction system, the reaction rate can be increased. Therefore, by introducing an inert gas such as nitrogen, argon, helium, carbon dioxide or a lower hydrocarbon gas which does not adversely influence the reaction, the generated aromatic monohydroxy compound is removed together with these gases. And a method of performing the reaction under reduced pressure are preferably used. The preferred reaction pressure depends on the molecular weight, and is 10 mmH at the beginning of polymerization.
g to normal pressure, and 20 mmH
g, especially 10 mmHg or less, preferably 2 mmHg
It is more preferable to set the following.

The melt polycondensation reaction can be carried out without adding a catalyst, but is carried out in the presence of a catalyst, if necessary, to increase the polymerization rate. The polymerization catalyst is not particularly limited as long as it is used in this field, but hydroxides of alkali metals or alkaline earth metals such as lithium hydroxide, sodium hydroxide, potassium hydroxide and calcium hydroxide are used. Alkali metal salts, alkaline earth metal salts, quaternary ammonium salts of boron hydrides such as sodium borohydride and tetramethylammonium borohydride; alkalis such as lithium hydride, sodium hydride and calcium hydride Hydrogen compounds of metals or alkaline earth metals; alkoxides of alkali metals or alkaline earth metals such as lithium methoxide, sodium ethoxide, calcium methoxide; lithium phenoxide, sodium phenoxide, magnesium phenoxide, LiO-Ar-OLi, NaO-A -ONa
(Ar is an aryl group) alkali metal or alkaline earth metal aryloxide; alkali metal or alkaline earth metal organic acid salts such as lithium acetate, calcium acetate, sodium benzoate; zinc oxide, zinc acetate, zinc phenoxide Zinc compounds such as boron oxide, boric acid, sodium borate, trimethyl borate, tributyl borate, triphenyl borate, (R ¹ R ² R ³ R ⁴ ) N
Ammonium borate represented by B (R ¹ R ² R ³ R ⁴ ), (R
¹ R ² R ³ R ⁴ ) phosphonium borates represented by PB (R ¹ R ² R ³ R ⁴ ) (R ¹ , R ² , R ³ , and R ⁴ are as described in Chemical formula 1), and the like. Silicon compounds such as silicon oxide, sodium silicate, tetraalkylsilicon, tetraarylsilicon, diphenyl-ethyl-ethoxysilicon; germanium oxide, germanium tetrachloride;
Germanium compounds such as germanium ethoxide and germanium phenoxide; tin compounds combined with alkoxy or aryloxy groups such as tin oxide, dialkyltin oxide, dialkyltin carboxylate, tin acetate and ethyltin tributoxide, and organotin compounds Tin compounds; lead compounds such as lead oxide, lead acetate, lead carbonate, basic carbonate, alkoxide or aryloxide of lead and organic lead; quaternary ammonium salts, quaternary phosphonium salts, quaternary arsonium salts Onium compounds such as; antimony oxide, antimony compounds such as antimony acetate; manganese acetate, manganese carbonate,
Examples of the catalyst include manganese compounds such as manganese borate; zirconium acetate, zirconium oxide, zirconium alkoxide or aryloxide, and zirconium compounds such as zirconium acetylacetone.

When a catalyst is used, these catalysts may be used alone or in combination of two or more. The amount of these catalysts to be used is usually 10 ^-8 to 100 parts by weight of the starting material aromatic dihydroxy compound.
1 part by weight, preferably in the range of 10 ^-7 to 10 ^-1 part by weight.

[0044]

Embodiments of the present invention will be described below in detail. -Moisture: Analyzed by Karl Fischer method. -Aluminum content: ICP (high frequency inductively coupled plasma emission spectrometer; JY38PI manufactured by Seiko Instruments Inc.)
Analyzed using I). -(P-phenoxyphenyl) (phenyl) carbonate content: analyzed by gas chromatography. Coloring: A solution obtained by dissolving 1 g of a sample in 7 ml of methylene chloride is placed in a cell having an optical path length of 1 cm, and the solution is measured by a spectrophotometer.
The absorbance at nm was measured and used as an index of coloring.

The ease of coloring at a high temperature is determined by heating an aromatic polycarbonate at 380 ° C. for 30 minutes in a nitrogen atmosphere.
Evaluation was made based on the increase in the absorbance at 400 nm due to heating. -Number average molecular weight (Mn): Gel permeation chromatography (GPC) using tetrahydrofuran as a solvent Column: TSK-GEL, Tosoh Corporation
The molecular weight was measured by a production method, and determined using a reduced molecular weight calibration curve obtained by the following equation using standard monodispersed polystyrene. M _PC = 0.3591M _PS ^1.0388 (wherein, M _PC molecular weight of the aromatic polycarbonate, M _PS
Indicates the molecular weight of polystyrene. The ease of molecular weight reduction at high temperature was evaluated by heating the aromatic polycarbonate at 380 ° C. for 30 minutes in a nitrogen atmosphere and reducing the number average molecular weight by heating.

[0046]

Example 1 After diphenyl carbonate was produced from dimethyl carbonate and phenol using triphenoxyaluminum as a catalyst, side cutting was performed in the gas phase at the second stage from the top of the column under the conditions of a pressure of 1596 Pa, a number of distillation stages of 5, and a reflux ratio of 3. And stored in a SUS304 container at 110 ° C. for 100 hours under a nitrogen atmosphere. 0.1 wt ppm of water content in diphenyl carbonate after storage,
Aluminum content 0.4 wtppm, (p-phenoxyphenyl) (phenyl) carbonate content 0.1 wtp
pm. Using the diphenyl carbonate, an aromatic polycarbonate was produced by a process as shown in FIG.

The stirred tank type polymerization vessel 3 was operated in a batch manner, and the storage tank 10 and subsequent ones were continuously operated. Stirring tank type polymerization vessel 3 (capacity 200 liters), 17 (capacity 50 liters), 26
(Capacity 50 liters) are all equipped with stirring blades. Horizontal twin-screw stirring type polymerization vessel 35 (capacity 30 liters)
Has a biaxial stirring blade with L / D = 6 and a rotating diameter of 140 mm. The perforated-plate polymerization unit 42 with a wire has a pore size of 5
a SUS316L wire 44 having a diameter of 1 mm vertically from the center of the hole.
Is hung down to the liquid reservoir at the bottom of the polymerization vessel, and the height at which it falls is 8 m.

The stirring tank type first polymerization vessel 3 has a reaction temperature of 180
° C, reaction pressure normal pressure, seal nitrogen gas flow rate 1 liter / h
r. 80 kg of sufficiently degassed bisphenol A and the above-mentioned diphenyl carbonate (molar ratio to bisphenol A 1.10) and 7 mg of sodium hydroxide were charged into the first polymerization vessel 3 of the stirring tank, and the mixture was melt-mixed for 5 hours and melted. A total of 350 molten polymers were transferred from the transfer pipe 7 to the storage tank 10 by pressure feeding.

The storage tank 10 is maintained at normal pressure and 180 ° C. The molten polymer transferred to the storage tank 10 was continuously supplied to the stirring tank type second polymerization device 17 at 10 kg / hr by the plunger pump 14. In the stirred tank type first polymerization vessel 3,
Before the molten polymer in the storage tank 10 runs out, a molten polymer having a number average molecular weight of 350 is produced in the same manner as described above, and transferred to the storage tank 10 again. Thereafter, similarly, a molten polymer having a number average molecular weight of 350 was produced batchwise in the first polymerization tank 3 of the stirring tank type, and was continuously supplied to the storage tank 10. Stirred tank type 2
The polymerization reactor 17 has a reaction temperature of 235 ° C. and a reaction pressure of 100 mm.
Under the condition of Hg, when the liquid volume of the molten polymer reaches 20 liters, the molten polymer having a number average molecular weight of 850 is continuously supplied to the third polymerization vessel 26 with a gear pump so as to keep the liquid volume constant at 20 liters. did. The stirring tank type third polymerization vessel 26 has a reaction temperature of 245 ° C. and a reaction pressure of 6 mmH.
g, and when the liquid volume of the molten polymer reaches 20 liters, the molten polymer having a number average molecular weight of 2,300 is continuously supplied to the horizontal twin-screw stirring type polymerizer 35 by a gear pump so as to keep the liquid volume at 20 liters. did. In the horizontal twin-screw polymerization reactor 35, the reaction temperature is 270 ° C. and the reaction pressure is 6
Under the conditions of 7 Pa, when the liquid volume of the molten polymer reaches 10 liters, the number average molecular weight of 6100 is added to the perforated plate type polymerizer 42 with a wire so as to keep the liquid volume constant at 10 liters.
Was fed by a gear pump. In the perforated plate type polymerization reactor 42 with wire, the reaction temperature is 260 ° C. and the reaction pressure is 53 Pa. When the liquid volume of the molten polymer in the lower part of the polymerization reactor reaches 20 liters, the transfer piping is maintained so as to maintain the liquid volume of 20 liters. The number average molecular weight is 10,000 from the extraction port 51 through 50, and the absorbance at 400 nm is 0.002.
A color-excellent aromatic polycarbonate of No. 7 was extracted.

After the obtained aromatic polycarbonate was heated at 380 ° C. for 30 minutes in a nitrogen atmosphere, the increase in absorbance was 0.0005, and the decrease in number average molecular weight was 300. Was also difficult to wake up.

[0051]

Example 2 Except that the storage conditions were 145 ° C. and 300 hours, the same production, purification and storage as in Example 1 were carried out. The water content was 0.1 wt ppm and the aluminum content was 0.4 wt pp.
m, an aromatic polycarbonate was produced in the same manner as in Example 1 by using diphenyl carbonate having a content of (p-phenoxyphenyl) (phenyl) carbonate of 0.3 wt ppm, and having a number average molecular weight of 10,000 and an absorbance of 400 nm at 0.0029. An aromatic polycarbonate having good color was obtained. After the obtained aromatic polycarbonate was heated at 380 ° C. for 30 minutes in a nitrogen atmosphere, the amount of increase in absorbance was 0.1%.
[0006] The decrease in the number average molecular weight was 300, and it was difficult to discolor even at high temperatures, and the molecular weight was hardly reduced.

[0052]

Example 3 Except that the storage conditions were 165 ° C. and 800 hours, the same procedure as in Example 1 was carried out to produce, purify, and store a water content of 0.1 wt ppm and an aluminum content of 0.4 wt pp.
m, an aromatic polycarbonate was produced in the same manner as in Example 1 by using diphenyl carbonate having a (p-phenoxyphenyl) (phenyl) carbonate content of 0.5 ppm by weight, and having a number average molecular weight of 10,000 and an absorbance of 0.0035 at 400 nm of 0.0035. An aromatic polycarbonate having good color was obtained. After the obtained aromatic polycarbonate was heated at 380 ° C. for 30 minutes in a nitrogen atmosphere, the amount of increase in absorbance was 0.1%.
[0008] The decrease in the number average molecular weight was 500, and it was difficult to color even at a high temperature, and the molecular weight was hardly reduced.

[0053]

Embodiment 4 SUS3 whose inner wall surface has been washed with phenol
Except for storage in a container made of No. 04, prepared, purified and stored in the same manner as in Example 3, water content 0.1 wt ppm, aluminum content 0.4 wt ppm, (p-phenoxyphenyl)
An aromatic polycarbonate was produced in the same manner as in Example 1 using diphenyl carbonate having a (phenyl) carbonate content of 0.2 wt ppm, and a number average molecular weight of 10,000,
An aromatic polycarbonate having an excellent absorbance at 400 nm and an absorbance of 0.0028 was obtained. The amount of increase in absorbance after heating the obtained aromatic polycarbonate at 380 ° C. for 30 minutes in a nitrogen atmosphere is 0.0005, and the decrease in number average molecular weight is 300. Therefore, it is difficult to discolor even at a high temperature and the molecular weight is hardly reduced. Was.

[0054]

Example 5 The same procedure as in Example 1 was carried out except that the number of distillation stages was set to 3 and the reflux ratio was set to 0.8.
Weight ppm, aluminum content 0.7 weight ppm, (p
Phenoxyphenyl) (phenyl) carbonate using diphenyl carbonate with a content of 0.1 ppm by weight,
An aromatic polycarbonate was produced in the same manner as in Example 1, and the number average molecular weight was 10,000 and the absorbance at 400 nm was 0.003.
An aromatic polycarbonate having a good color was obtained. The amount of increase in absorbance after heating the obtained aromatic polycarbonate at 380 ° C. for 30 minutes under a nitrogen atmosphere is 0.0009,
The decrease in the number average molecular weight was 700, and it was difficult to color even at a high temperature, and the molecular weight was hard to decrease.

[0055]

Example 6 The procedure of Example 1 was repeated except that the number of distillation stages was 3 and the reflux ratio was 0.1.
0 weight ppm, aluminum content 0.9 weight ppm,
(P-phenoxyphenyl) (phenyl) carbonate An aromatic polycarbonate was produced in the same manner as in Example 1 by using diphenyl carbonate having a content of 0.1 wt ppm, and the number average molecular weight was 10,000, and the absorbance at 400 nm was 0.4.
Thus, an aromatic polycarbonate having a good color was obtained. The obtained aromatic polycarbonate was dried under nitrogen atmosphere.
The amount of increase in absorbance after heating at 80 ° C. for 30 minutes is 0.0
013, the decrease in the number average molecular weight was 900, and it was difficult to color even at a high temperature, and the molecular weight was hard to decrease.

[0056]

Example 7 Production, purification and storage were carried out in the same manner as in Example 1, except that the mixture was stored in an atmosphere of 0.5% by volume of oxygen and 99.5% by volume of nitrogen. 0.4 wt ppm, (p-phenoxyphenyl)
An aromatic polycarbonate was produced in the same manner as in Example 1 using diphenyl carbonate having a (phenyl) carbonate content of 0.9 wt ppm, and a number average molecular weight of 10,000,
A slightly colored aromatic polycarbonate with an absorbance at 400 nm of 0.004 was obtained. The amount of increase in absorbance after heating the obtained aromatic polycarbonate at 380 ° C. for 30 minutes under a nitrogen atmosphere is 0.002, and the decrease in number average molecular weight is 900, so that it is difficult to color at a high temperature and the molecular weight is hardly reduced. Was.

[0057]

[Comparative Example 1] Except not purifying by distillation, it was produced and stored in the same manner as in Example 1; moisture: 250 ppm by weight; aluminum content: 1.5 ppm by weight; (p-phenoxyphenyl) (phenyl) carbonate content: 0.1 ppm by weight. An aromatic polycarbonate was produced in the same manner as in Example 1 by using diphenyl carbonate of
A colored aromatic polycarbonate having an absorbance of 0 nm and 0.0049 was obtained. The amount of increase in absorbance after heating the obtained aromatic polycarbonate at 380 ° C. for 30 minutes in a nitrogen atmosphere is 0.0037, and the decrease in number average molecular weight is 1500.
It was easy to color at high temperature, and the molecular weight was significantly reduced.

[0058]

COMPARATIVE EXAMPLE 2 Except for storage under an atmosphere of 2% by volume of oxygen and 98% by volume of nitrogen, the same production, purification and storage as in Example 1 were carried out.
An aromatic polycarbonate was produced in the same manner as in Example 1 by using diphenyl carbonate having a content of 4 ppm by weight and (p-phenoxyphenyl) (phenyl) carbonate content of 1.2 ppm by weight, and a number average molecular weight of 10,000 and 400 n.
Thus, a colored aromatic polycarbonate having an absorbance at m of 0.0059 was obtained. The amount of increase in absorbance after heating the obtained aromatic polycarbonate at 380 ° C. for 30 minutes under a nitrogen atmosphere was 0.0044, the amount of decrease in number average molecular weight was 1,400, and it was easy to color at a high temperature, and the decrease in molecular weight was large. .

[0059]

According to the present invention, a high-quality aromatic polycarbonate having good color, little coloring even at a high temperature of 380 ° C. or more, and a small decrease in molecular weight can be produced by an industrially preferable method.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an example of the process of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Raw material supply port 2, 9, 19, 28, 36, 46 Vent port 3 Stirring tank type 1st polymerization machine 4, 18, 27, 39 Stirring shaft 5, 11, 20, 29, 47 Molten polymer 6, 12, 21 , 30, 37, 48 Discharge port 7, 13, 15, 24, 33, 40, 50 Transfer pipe 8, 16, 25, 34, 41 Supply port 10 Storage tank 14, 23, 32, 38, 49 Transfer pump 17 Stirring tank Type second polymerization device 22, 31, 45 Gas supply port 26 Stirring tank type third polymerization device 35 Horizontal twin-screw type polymerization device 42 Perforated plate type polymerization device with wire 43 Perforated plate 44 Wire 51 Product outlet

Claims (3)

[Claims] 1. A method for producing an aromatic polycarbonate by polymerization in a molten state from an aromatic dihydroxy compound and a diaryl carbonate, wherein the diaryl carbonate has (a) a water content of 200 ppm by weight or less; A method for producing an aromatic polycarbonate, wherein the content of aluminum is 1 ppm by weight or less, and the content of (c) (p-phenoxyphenyl) (phenyl) carbonate is 1 ppm by weight or less. 2. A diaryl carbonate having a water content of 200 ppm by weight or less and (b) a diaryl carbonate having an aluminum content of 1 ppm by weight or less in a stainless steel container in a nitrogen atmosphere under a nitrogen atmosphere of 80 to 19 ppm.
The method for producing an aromatic polycarbonate according to claim 1, wherein the diaryl carbonate is stored in a molten state at a temperature of 0 ° C. 3. The container made of stainless steel is a container whose inner wall surface has been subjected to a washing treatment with phenol.
A method for producing the aromatic polycarbonate according to the above.