JP2002053656A - Manufacturing method of aromatic polycarbonate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce an aromatic polycarbonate by a melt polycondensation method, which has good color, has little coloration even at a high temperature of 380 ° C. or higher, and has a small decrease in molecular weight. It provides an economically preferable production method. SOLUTION: In a method for producing an aromatic polycarbonate by polymerization in a molten state from an aromatic dihydroxy compound and a diaryl carbonate, the diaryl carbonate has (a) a water content of 200 ppm by weight or less; The content is 1 ppm by weight or less,
(C) The content of o-phenylene carbonate is 2 ppm by weight.
A method for producing an aromatic polycarbonate using:

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 applications as a molding material for injection molding and as a molding material for molded articles requiring high transparency, molding is generally carried out at a higher temperature than ordinary resins. The applications as required molding materials for precision molded products are expanding, and aromatic polycarbonates with little coloring even when molded at high temperatures are 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, there has been a strong demand for an aromatic polycarbonate which has little coloring and a small molecular weight reduction even at a high temperature of 380 ° C. or higher.

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

[0005] However, these inventions are not always sufficient to improve color, and furthermore, it has not been possible 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.

[0006]

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.

[0007]

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 relates to (1) a method for producing an aromatic polycarbonate which is polymerized in a molten state from an aromatic dihydroxy compound and a diaryl carbonate, wherein (a) water in the diaryl carbonate is 200%.
(B) the copper content is 1 ppm by weight or less, and (c) the o-phenylene carbonate content is 2 ppm or less.
A method for producing an aromatic polycarbonate, which is not more than ppm by weight, (2) a diaryl carbonate,
(A) a water content of 200 ppm by weight or less;
Diaryl carbonate having a copper content of 1 ppm by weight or less was placed in a stainless steel container under a nitrogen atmosphere at 80 to 19%.
(1) The method for producing an aromatic polycarbonate according to (1), wherein the diaryl carbonate is stored in a molten state at a temperature of 0 ° C .; The method for producing an aromatic polycarbonate according to (2), wherein the container has been subjected to a washing treatment. When producing an aromatic polycarbonate by a melt polymerization method, usually, the raw material diaryl carbonate is not 100% pure, and various compounds derived from the method for producing the diaryl carbonate or the method for storing the produced diaryl carbonate are used. It contains. 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, copper which is a catalyst component used for producing diaryl carbonate, and o-phenylene carbonate produced when diaryl carbonate is stored in a molten state. Surprisingly, the color of the product aromatic polycarbonate is improved, and the stability at high temperatures of 380 ° C. or higher and the stability against molecular weight reduction are remarkably improved. It became clear that

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, -A
r ¹ —Y—Ar ² — (wherein, Ar ¹ and Ar ² each independently represent a divalent carbocyclic or heterocyclic aromatic group having 5 to 70 carbon atoms, and Y represents 1 carbon atom To 30 divalent substituted or unsubstituted alkane groups.). In the divalent aromatic groups Ar ¹ and Ar ² , at least one hydrogen atom has another substituent that does not adversely influence the reaction, for example, a halogen atom, an alkyl group having 1 to 10 carbon atoms, 10 alkoxy groups, phenyl groups, phenoxy groups, vinyl groups, cyano groups, ester groups,
It may be substituted by an amide group, a nitro group or the like. 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 groups such as 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.

[0012]

Embedded image (Wherein R ¹ , R ² , R ³ and R ⁴ are each independently hydrogen,
C1-C10 alkyl group, C1-C10 alkoxy group, C5-C10 cycloalkyl group, C5-C10 carbocyclic aromatic group, C6-C1
Represents a carbocyclic aralkyl group of 0. k represents an integer of 3 to 11, R ⁵ and R ⁶ are individually selected for each X, and each independently represents hydrogen or an alkyl group having 1 to 6 carbon atoms, and X represents carbon. R ¹ , R ² ,
In R 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 carbon atom may be used as long as one or more hydrogen atoms do not adversely affect the reaction.
It may be substituted by 10 to 10 alkoxy groups, phenyl groups, phenoxy groups, vinyl groups, cyano groups, ester groups, amide groups, nitro groups and the like. Examples of such a divalent aromatic group Ar include those represented by the following chemical formula 2.

[0013]

Embedded image (Wherein, R ⁷ and R ⁸ are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a cycloalkyl group having 5 to 10 ring carbon atoms, or A phenyl group, m and n are integers of 1 to 4, and when m is 2 to 4, each R ⁷ may be the same or different, and when n is 2 to 4, And each R ⁸ may be the same or different.) Further, the divalent aromatic group Ar is -Ar ¹ -Z-Ar ²
— (Wherein, Ar ¹ and Ar ² are as described above, and Z is a single bond or —O—, —CO—, —S—, —SO ₂ —, and —SO
-, - COO -, - CON (R 1) - represents a divalent group, such as. Here, R ¹ is as described above. ) May be used. Such a divalent aromatic group Ar
Examples thereof include those shown in Chemical Formula 3 below.

[0014]

Embedded image  (Where R⁷, R⁸, M and n are as described above.
You. Further, specific examples of the divalent aromatic group Ar include substitution and substitution.
Or unsubstituted phenylene, substituted or unsubstituted naphthyl
And substituted or unsubstituted pyridylene. Book
The aromatic dihydroxy compound used in the present invention is a single kind
Or two or more types. Aromatic dihydroxy
Typical examples of the compound include bisphenol A.
It is. The diaryl carbonate used in the present invention is
It is represented by the following formula 4.

[0015]

Embedded image (Wherein, Ar ^3, Ar ⁴ represents a monovalent aromatic group, respectively.) Ar ³ and Ar ⁴ represent a monovalent carbocyclic or heterocyclic aromatic group, this Ar ^3, Ar ⁴ , in which one or more hydrogen atoms do not adversely affect the reaction, such as a halogen atom, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a phenyl group, and a phenoxy group. , A vinyl group, a cyano group, an ester group, an amide group, a nitro group, or the like. Ar ³
And Ar ⁴ may be the same or different. 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 Ar ³ and Ar ⁴
Examples thereof include, for example, those shown in Chemical Formula 5 below.

[0016]

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

[0017]

Embedded image (Wherein R ⁹ and R ¹⁰ each independently represent a hydrogen atom,
An alkyl group having 10 to 10, an alkoxy group having 1 to 10 carbon atoms, a cycloalkyl group having 5 to 10 ring carbon atoms or a phenyl group, p and q are integers of 1 to 5, p
There the case of two or more, may be each R ⁹ is different from each other, when q is 2 or more, each R ^{1 0} may be different from each other. 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. 20 moisture
If the content is more than 0 ppm by weight, the color of the product 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 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 1
It is at most 00 ppm by weight, more preferably at most 50 ppm by weight. There is no particular limitation on the lower limit of the water content,
The water content may be less than 0.01 ppm by weight, but if less than 0.01 ppm by weight, 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 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 dehydrating by distillation or the like when moisture is absorbed and becomes a water amount higher than the upper limit of 200 wt ppm. After performing the operation, a method used for the polymerization of the aromatic polycarbonate may, for example, be mentioned.

In the present invention, the copper content in the diaryl carbonate is 1 ppm by weight or less. When the copper content is more than 1 ppm by weight, the color of the product aromatic polycarbonate is deteriorated, and the product is easily 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 copper acts catalytically on the coloring reaction and the molecular weight reduction reaction of the aromatic polycarbonate at high temperatures. The copper content 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 copper content is not particularly limited, and the copper content may be less than 0.001 weight ppm. However, even if the copper content is less than 0.001 weight ppm, the coloring of the aromatic polycarbonate at a high temperature is performed. And the effect of improving molecular weight reduction is small. As a method of controlling the copper content within the above range, when producing the diaryl carbonate, no copper catalyst is used, or after the diaryl carbonate is produced using the copper catalyst, the copper content is reduced by a distillation operation, a washing operation, or the like. And the like. However, in the case of producing a diaryl carbonate without using any copper catalyst, 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 o-phenylene carbonate in the diaryl carbonate is 2 ppm by weight.
It is as follows. When the content of o-phenylene carbonate is more than 2 ppm by weight, the color of the product aromatic polycarbonate deteriorates, and the product tends to be colored at a high temperature of 380 ° C. or higher. Although the reason for this is not clear, o-
It is presumed that phenylene carbonate itself or a reaction product of o-phenylene carbonate and an aromatic polycarbonate tends to be colored at a high temperature. The content of o-phenylene carbonate in the diaryl carbonate is preferably 1 ppm by weight or less, more preferably 0.2 ppm by weight.
m or less. The lower limit of the content of o-phenylene carbonate is not particularly limited, and the content of o-phenylene carbonate may be less than 0.01 ppm by weight, but the content of o-phenylene carbonate may be less than 0.01 ppm by weight. The effect of improving the coloring of the aromatic polycarbonate at high temperatures is small.

When producing an aromatic polycarbonate from an aromatic dihydroxy compound and a diaryl carbonate,
For good industrial handling, the diaryl carbonate is usually used after it has been stored in the molten state. In the present invention, the diaryl carbonate is used in a stainless steel container in a nitrogen atmosphere at 80 to 190.
It is preferably stored in a molten state at a temperature of ° C. If the storage container is made of carbon steel,
The production amount of o-phenylene carbonate may increase. Stainless is the Stainless Steel Handbook No. 13-21
Stainless steel such as martensitic, ferritic, austenitic, ferritic-austenite, etc., usually containing 10 to 30% by weight of chromium as defined and classified on the page (published by Nikkan Kogyo Shimbun, fifth edition); Examples thereof include Fe-based superalloys as shown in the table on page 547 of the Stainless Steel Handbook. Specific examples include SUS201, SUS
202, SUS304, SUS304L, SUS31
6, SUS316L, SUS347, SUS405, S
US430, SUS403, SUS410, SUS43
1, SUS440C, SUS630, Incoloy 80
0, Incoloy 801, Incoloy 802, Incoloy 807, Incoloy 901, LCN155, W545,
V57, W545, D979, CG27, S590 and the like. Preferred specific examples are SUS304, S
US304L, SUS316, SUS316L, and the like, and particularly preferably, SUS304.

It is preferable that the liquid contact portion on the inner wall surface of the stainless steel container has been subjected to a washing treatment with phenol. When a stainless steel container washed with phenol is used, the amount of o-phenylene carbonate produced can be particularly reduced. Although the reason is not clear, it is presumed that the removal of oxygen adsorbed on the stainless steel surface with phenol prevents the production of o-phenylene carbonate. The storage is preferably performed under a nitrogen atmosphere. When air is mixed in the storage container, the amount of o-phenylene carbonate generated 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 o-phenylene 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 85 to 160 ° C, and still more preferably 90 to 14 ° C.
0 ° C.

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 type of the aromatic dihydroxy compound and the diaryl carbonate 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 1
00000, preferably 5000 to 300
00 range.

In the process for producing the aromatic polycarbonate of the present invention, the aromatic dihydroxy compound and the diaryl carbonate are heated under reduced pressure and / or inert gas flow in the presence or absence of a catalyst. This is a method in which polycondensation is performed by transesterification in a molten state, and the polymerization vessel is not particularly limited. 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 Reactor,
A perforated plate reactor with a wire or the like, which polymerizes while being dropped along a wire, is used, and a polymerizer combining these alone or in combination is used. 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 an aromatic polycarbonate by reacting an aromatic dihydroxy compound with a diaryl carbonate, the reaction temperature is usually 50 to 350 ° C, preferably 100 to 300 ° C.
Temperature range.

As the reaction proceeds, an aromatic monohydroxy compound is produced, and by removing this from the reaction system, the reaction rate can be increased. Therefore, nitrogen,
Introduce inert gases that do not adversely affect the reaction, such as argon, helium, carbon dioxide and lower hydrocarbon gas,
A method of removing the generated aromatic monohydroxy compound by accompanying these gases, a method of performing a reaction under reduced pressure, and the like are preferably used. The preferred reaction pressure is
It varies depending on the molecular weight.
The range of normal pressure is preferred, and in the late stage of the polymerization, it is preferably 20 mmHg or less, particularly preferably 10 mmHg or less, and more preferably 2 mmHg or less.

Although the melt polycondensation reaction can be carried out without adding a catalyst, it is carried out in the presence of a catalyst if necessary in order 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 ) ammonium borates represented by NB (R ¹ R ² R ³ R ⁴ ); (R ¹ R ² R ³ R ⁴ ) PB (R ¹ R ² R
³ R ⁴ ) represented by phosphonium borates (R ¹ , R
² , R ³ and R ⁴ are as described in the above formula 1. Compounds of boron such as silicon oxide, sodium silicate, tetraalkylsilicon, tetraarylsilicon, diphenyl-ethyl-ethoxysilicon;
Germanium compounds such as germanium oxide, germanium tetrachloride, germanium ethoxide, germanium phenoxide; tin oxide, dialkyltin oxide,
Tin compounds such as dialkyltin carboxylate, tin acetate, tin compounds bonded to alkoxy or aryloxy groups such as ethyltin tributoxide, and organic tin compounds; lead oxide, lead acetate, lead carbonate, basic carbonate,
Lead compounds such as alkoxides or aryloxides of lead and organolead; onium compounds such as quaternary ammonium salts, quaternary phosphonium salts and quaternary arsonium salts; antimony compounds such as antimony oxide and antimony acetate; acetic acid Examples of the catalyst include manganese compounds such as manganese, manganese carbonate, and manganese borate; zirconium acetate, zirconium oxide, zirconium alkoxide or zirconium compounds such as zirconium acetylacetone, and the like.

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.

[0028]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail with reference to embodiments of the present invention. -Moisture: Analyzed by Karl Fischer method. -Copper content: Analyzed using ICP (high frequency inductively coupled plasma emission spectrometer; JY38PII manufactured by Seiko Instruments Inc.). O-phenylene 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. Ease of coloring at high temperature: The aromatic polycarbonate was heated at 380 ° C. for 30 minutes in a nitrogen atmosphere, and the increase in the absorbance at 400 nm due to heating was evaluated. -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. -Easiness of molecular weight reduction at high temperature: The aromatic polycarbonate was heated at 380 ° C for 30 minutes in a nitrogen atmosphere, and evaluated by the amount of decrease in the number average molecular weight due to heating.

[0029]

Example 1 After diphenyl carbonate was prepared from dimethyl carbonate and phenol using diphenoxy copper as a catalyst, the pressure was 1596 Pa, the number of distillation stages was 5, and the reflux ratio was 3.
Under the condition of 0, side-cut in the gas phase of the second stage from the top of the column to purify by distillation, and in a SUS304 container under a nitrogen atmosphere,
Stored at 105 ° C for 100 hours. The water content of the diphenyl carbonate after storage is 0.1 wt ppm, and the copper content is 0.1 ppm.
4 wt ppm, o-phenylene carbonate content 0.1
It was ppm by weight. 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 first polymerization vessel 3 of the stirring tank type 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. 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
005, the amount of decrease in the number average molecular weight was 300, and it was difficult to discolor even at a high temperature, and the molecular weight was hardly reduced.

[0033]

Example 2 Except that the storage conditions were 143 ° C. and 300 hours, the same procedure as in Example 1 was carried out to produce, purify and store a water content of 0.1 wt ppm, a copper content of 0.4 wt ppm, and o-phenylene carbonate. Using diphenyl carbonate having a content of 0.3 wt ppm, an aromatic polycarbonate was produced in the same manner as in Example 1, and a number average molecular weight of 10,000, 400
An aromatic polycarbonate having a good color with an absorbance of 0.0029 nm was obtained. After the obtained aromatic polycarbonate was heated at 380 ° C. for 30 minutes in a nitrogen atmosphere, the increase in absorbance was 0.0006, and the decrease in number average molecular weight was 300.
It was difficult to be colored even at a high temperature, and the molecular weight was hardly reduced.

[0034]

Example 3 Except that the storage conditions were changed to 167 ° C. and 800 hours, the same production, purification and storage were carried out as in Example 1; water content 0.1 wt ppm, copper content 0.4 wt ppm, o-phenylene carbonate Using diphenyl carbonate having a content of 0.8 wt ppm, an aromatic polycarbonate was produced in the same manner as in Example 1, and the number average molecular weight was 10,000, 400
An aromatic polycarbonate having a good color with an absorbance of 0.0034 nm was obtained. After the obtained aromatic polycarbonate was heated at 380 ° C. for 30 minutes in a nitrogen atmosphere, the increase in absorbance was 0.0008, and the decrease in number average molecular weight was 500.
It was difficult to be colored even at a high temperature, and the molecular weight was hardly reduced.

[0035]

Embodiment 4 SUS3 whose inner wall surface has been washed with phenol
Except for storage in a container made of P.04, the same production, purification and storage as in Example 3 were carried out.
4 wt ppm, o-phenylene carbonate content 0.4
An aromatic polycarbonate was produced in the same manner as in Example 1 by using diphenyl carbonate in an amount of ppm by weight to obtain an aromatic polycarbonate having a number average molecular weight of 10,000 and an absorbance of 0.0028 at 400 nm and a good color. 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.

[0036]

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.
Aromatic polycarbonate was produced in the same manner as in Example 1 by using diphenyl carbonate having a weight ppm of copper, 0.7 weight ppm of copper, and 0.1 weight ppm of o-phenylene carbonate, and having a number average molecular weight of 10,000 and an absorbance of 400 nm. An aromatic polycarbonate having a good color of .0033 was obtained. The amount of increase in absorbance of the obtained aromatic polycarbonate after heating at 380 ° C. for 30 minutes in a nitrogen atmosphere is 0.0009, and the decrease in number average molecular weight is 700. Was.

[0037]

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.
An aromatic polycarbonate was produced in the same manner as in Example 1 by using diphenyl carbonate having 0 wt ppm, copper content of 0.9 wt ppm, and o-phenylene carbonate content of 0.1 wt ppm, and having a number average molecular weight of 10,000 and 400 nm.
Of an aromatic polycarbonate having a good absorbance of 0.0038 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 0.0013, and the decrease in number average molecular weight is 900, so that it is difficult to discolor even at a high temperature and the molecular weight is hardly reduced. Was.

[0038]

Example 7 Except for storage under an atmosphere of 0.5% by volume of oxygen and 99.5% by volume of nitrogen, the same production, purification and storage as in Example 1 were carried out. 0.
4 ppm by weight, o-phenylene carbonate content 1.8
An aromatic polycarbonate was produced in the same manner as in Example 1 by using diphenyl carbonate in a weight ppm, and a slightly colored aromatic polycarbonate having a number average molecular weight of 10,000 and an absorbance of 400 nm at 400 nm was obtained. The obtained aromatic polycarbonate is treated at 380 ° C. under nitrogen atmosphere for 30 minutes.
The amount of increase in absorbance after heating for one minute was 0.0019, and the amount of decrease in number average molecular weight was 900. Thus, coloring was difficult at high temperatures and the molecular weight was hardly reduced.

[0039]

COMPARATIVE EXAMPLE 1 Diphenyl carbonate prepared and stored in the same manner as in Example 1 except that distillation purification was not performed, using 250 ppm by weight of water, 1.5 ppm by weight of copper, and 0.1 ppm by weight of o-phenylene carbonate. An aromatic polycarbonate was produced in the same manner as in Example 1 to obtain a colored aromatic polycarbonate having a number average molecular weight of 10,000 and an absorbance of 0.0048 at 400 nm. The amount of increase in absorbance after heating the obtained aromatic polycarbonate at 380 ° C. for 30 minutes under a nitrogen atmosphere was 0.0036, the amount of decrease in number average molecular weight was 1500, and it was easy to color at a high temperature, and the decrease in molecular weight was large. .

[0040]

Comparative Example 2 Except for storage in an atmosphere of 2% by volume of oxygen and 98% by volume of nitrogen, manufactured, purified and stored in the same manner as in Example 1, having a water content of 0.1 wt ppm and a copper content of 0.4 wt. pp
m, o-phenylene carbonate content 2.4 wt ppm
An aromatic polycarbonate was produced in the same manner as in Example 1 by using diphenyl carbonate, and the number average molecular weight was 100.
A colored aromatic polycarbonate having an absorbance of 0.0058 at 00 and 400 nm was obtained. The amount of increase in absorbance after heating the obtained aromatic polycarbonate at 380 ° C. for 30 minutes in a nitrogen atmosphere was 0.0043, and the decrease in number average molecular weight was 1400. .

[0041]

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 flowchart showing an example of a process for producing an aromatic polycarbonate of the present invention.

[Explanation of symbols]

 1: Raw material supply port 2, 9, 19, 28, 36, 46: Vent port 3: Stirring tank type first polymerization device 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: Stirred tank type second polymerization unit 22, 31, 45: Gas supply port 26: Stirred tank type third polymerization unit 35: Horizontal biaxial stirring type polymerization unit 42: Perforated plate type with wire Polymerizer 43: Perforated plate 44: Wire 51: Product outlet

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4J029 AA09 AB04 AB07 AE01 BB10A BB10B BB12A BB12B BB12C BB13A BB13B BB13C BD09A BD09B BD09C BE05A BE05B BE07 BF14A BF14B BH01 BH02 DA10 DB07 DB05 DB10

Claims (3)

[Claims] 1. A method for producing an aromatic polycarbonate which is polymerized 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;
(B) A method for producing an aromatic polycarbonate, wherein the copper content is 1 ppm by weight or less and (c) the content of o-phenylene carbonate is 2 ppm by weight or less. 2. A diaryl carbonate comprising: (a) a water content of not more than 200 ppm by weight; and (b) a copper content of 1%.
2. The aromatic polycarbonate according to claim 1, wherein the diaryl carbonate having a weight of not more than ppm is a diaryl carbonate stored in a molten state at a temperature of 80 to 190 [deg.] C. under a nitrogen atmosphere in a stainless steel container. Law. 3. The method for producing an aromatic polycarbonate according to claim 2, wherein the stainless steel container is a container in which the liquid contact portion on the inner wall surface has been subjected to a washing treatment with phenol.