JP2002105192A - Method for producing aromatic polycarbonate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an industrially preferable method for producing a high- quality aromatic polycarbonate having an excellent color, slightly discoloring even at a high temperature of >=380 deg.C and having a slight reduction in molecular weight in producing an aromatic polycarbonate by a melt polycondensation method. SOLUTION: In this method for producing an aromatic polycarbonate from an aromatic dihydroxy compound and a diaryl carbonate by polymerization in a melt state, the method for producing the aromatic carbonate uses a diaryl carbonate having (a) <=200 wt.ppm water content, (b) <=1 wt.ppm titanium content and (c) <=1 wt.ppm o,p'-bis(phenoxycarboxyl)biphenyl content is used as the diaryl 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-8-1047
No. 47 discloses that the amount of an aromatic dihydroxy compound having a specific structure is 10% by weight or more and 3% by weight or less, and JP-A-8-104748 discloses that a specific bisphenol A derivative, a bisphenol A isomer, Total content of organic compound, trisphenol I is 100
Bisphenol A not less than 1000 ppm and not more than 1000 ppm
In JP-A-11-310630,
The content of the specific compound in the aromatic dihydroxy compound is defined, such as using bisphenol A having a chroman organic compound content of 200 ppm or less and an iron content of 0.1 ppm or less. However, these inventions are not always sufficient to improve color, and furthermore, it has not been possible to provide an aromatic polycarbonate which is less colored 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 method for producing a novel 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 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 of the diaryl carbonate is 2%.
Aromatic polycarbonate characterized by being not more than 00 ppm by weight, (b) having a titanium content of not more than 1 ppm by weight, and (c) having o, p'-bis (phenoxycarboxyl) biphenyl content of not more than 1 ppm by weight. Manufacturing method,
(2) Diaryl carbonate having a water content of 200 ppm by weight or less and (b) a diaryl carbonate having a titanium content of 1 ppm by weight or less under a nitrogen atmosphere in a stainless steel container at 80 to 190 ° C. (1) The method for producing an aromatic polycarbonate according to (1), which is a diaryl carbonate stored in a molten state at a temperature. (3) A stainless steel container is subjected to a washing treatment with phenol on a liquid contact portion on an inner wall surface. (2) The method for producing an aromatic polycarbonate according to (2), wherein the container is an applied container.

In the production of an aromatic polycarbonate by a melt polymerization method, usually, the raw material diaryl carbonate is not 100% pure, but is derived from the production method of the diaryl carbonate or the storage method of 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 intensive studies by the present inventors, it has been found that water mixed by moisture absorption, titanium which is a catalyst component used for producing a diaryl carbonate, and o, p 'generated when diaryl carbonate is stored in a molten state.
By setting the content of -bis (phenoxycarboxyl) biphenyl to a specific value or less, the color of the aromatic polycarbonate product is surprisingly improved, and coloring and molecular weight reduction at a high temperature of 380 ° C or higher are surprisingly achieved. It has been found that the stability against the phenomena 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 ,
One or more hydrogen atoms having no adverse effect on the reaction, for example, a halogen atom, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a phenyl group,
It may be substituted by a phenoxy group, vinyl group, cyano group, ester group, amide group, nitro group, or the like. Preferred specific examples of the heterocyclic aromatic group include 1
And an aromatic group having a plurality of ring-forming nitrogen atoms, oxygen atoms 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,
Is an organic group represented by

Embedded image

(Wherein R ¹ , R ² , R ³ , and R ⁴ each independently represent hydrogen, an alkyl group having 1 to 10 carbon atoms,
10 alkoxy groups, a cycloalkyl group having 5 to 10 ring carbon atoms, a carbocyclic aromatic group having 5 to 10 ring carbon atoms,
Represents a carbocyclic aralkyl group having 6 to 10 carbon atoms. k is 3
And R5 and R6 are individually selected for each X and independently of one another, hydrogen or C1
And X represents carbon. R ¹ ,
In R ² , R ³ , R ⁴ , R ⁵ and R ⁶ , other substituents as long as one or more hydrogen atoms do not adversely affect the reaction,
For example, those substituted by a halogen atom, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a phenyl group, a phenoxy group, a vinyl group, a cyano group, an ester group, an amide group, a nitro group, etc. May be. )

As such a divalent aromatic group Ar,
For example, those shown in the following chemical formula 2 can be mentioned.

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, and a cyclo group 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. ) Further, the divalent aromatic group Ar is -Ar ¹
-Z-Ar ² - may be one represented by. (Wherein, Ar ¹ and Ar ² are as described above, and Z is a single bond or −
O -, - CO -, - S -, - SO 2 -, - SO -, - C
^{OO -, - CON (R 1} ) - represents a divalent group, such as. Here, R ¹ is as described above. )

As such a divalent aromatic group Ar,
For example, those shown in Chemical Formula 3 below can be mentioned.

Embedded image (In the formula, R ⁷ , R ⁸ , m and n are as described above.)

Further, specific examples of the divalent aromatic group Ar include substituted or unsubstituted phenylene, substituted or unsubstituted naphthylene, and substituted or unsubstituted pyridylene. 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 represented by the following chemical formula 4.

Embedded image (In the formula, Ar ³ and Ar ⁴ each represent a monovalent aromatic group.)

Ar ³ and Ar ⁴ represent a monovalent carbocyclic or heterocyclic aromatic group. In Ar ³ and Ar ⁴ , one or more hydrogen atoms may have no adverse effect on the reaction. Substituents, for example, a halogen atom, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a phenyl group, a phenoxy group, a vinyl group, a cyano group, an ester group,
It may be substituted by an amide group, a nitro group or the like. Ar ³ and Ar ⁴ may be the same or different. Monovalent aromatic group Ar ³
And typical examples of 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 those represented by the following formula 5, respectively.

Embedded image

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

Embedded image (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 1 to 10 carbon atoms, a cycloalkyl group having 5 to 10 ring carbon atoms, or phenyl Represents a group, p and q are integers of 1 to 5,
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 the diphenyl carbonates,
Unsubstituted diphenyl carbonate, symmetric diaryl carbonates such as lower alkyl-substituted diphenyl carbonates such as ditolyl carbonate and di-t-butylphenyl carbonate are preferred, but unsubstituted diphenyl which is a diaryl carbonate having the simplest structure is particularly preferred. Carbonates are 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 titanium content in the diaryl carbonate is 1 ppm by weight or less. When the titanium 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 titanium catalytically acts on the coloring reaction and the molecular weight reduction reaction of the aromatic polycarbonate at high temperatures. The titanium content in the diaryl carbonate is preferably 0.5 wt.
pm or less, more preferably 0.1 ppm by weight or less. There is no particular limitation on the lower limit of the titanium content,
The titanium content may be less than 0.001 wt ppm, but if the titanium content is less than 0.001 wt ppm, 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 titanium content within the above range, when producing a diaryl carbonate,
A method in which a titanium catalyst is not used at all or a diaryl carbonate is produced using a titanium catalyst, and then the titanium content is reduced by a distillation operation, a washing operation, or the like. However, when the diaryl carbonate is produced without using any titanium 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, p'-bis (phenoxycarboxyl) biphenyl in the diaryl carbonate is 1 weight p.
pm or less. When the content of o, p'-bis (phenoxycarboxyl) biphenyl is more than 1 ppm by weight,
The color of the product aromatic polycarbonate deteriorates and 3
It becomes easy to color at a high temperature of 80 ° C. or higher.

Although the reason is not clear,
It is presumed that o, p'-bis (phenoxycarboxyl) biphenyl itself or a reaction product of o, p'-bis (phenoxycarboxyl) biphenyl and an aromatic polycarbonate tends to be colored at high temperatures. The content of o, p'-bis (phenoxycarboxyl) biphenyl 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 o, p'-bis (phenoxycarboxyl) biphenyl is not particularly limited, and is 0.01 wt.
The o, p'-bis (phenoxycarboxyl) biphenyl content may be less than m, but the o, p'-bis (phenoxycarboxyl) biphenyl content is less than 0.01 ppm by weight. The effect of improving coloring 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, the amount of o, p'-bis (phenoxycarboxyl) biphenyl 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.

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, particularly the amount of o, p'-bis (phenoxycarboxyl) biphenyl can be reduced. Although the reason for this is not clear, it is presumed that removal of adsorbed oxygen on the stainless steel surface with phenol prevents formation of o, p'-bis (phenoxycarboxyl) biphenyl. The storage is preferably performed under a nitrogen atmosphere. When air is mixed into the storage container, the amount of o, p'-bis (phenoxycarboxyl) biphenyl generated increases. Storage temperature is 80 ~
The temperature is preferably in the range of 190 ° C., and when it is higher than 190 ° C., o, p′-bis (phenoxycarboxyl)
The amount of biphenyl produced 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 preferable storage temperature range is 85 to 160 ° C, and further preferably 90 to 140 ° C.
° 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 an aromatic polycarbonate of the present invention, the aromatic dihydroxy compound and the diaryl carbonate are heated under reduced pressure and / or under an 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 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 generated. By removing this from the reaction system, the reaction rate can be increased. Therefore,
Introducing an inert gas such as nitrogen, argon, helium, carbon dioxide or lower hydrocarbon gas which does not adversely affect the reaction, and removing the generated aromatic monohydroxy compound with these gases. Alternatively, a method of performing the reaction under reduced pressure is preferably used. The preferred reaction pressure depends on the molecular weight, and is 10 mm at the beginning of polymerization.
Hg to normal pressure is preferable, and 20 mm
Hg or less, especially 10 mmHg or less, preferably 2 mmHg
g or less.

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 hydrides of boron and aluminum such as lithium aluminum hydride, sodium borohydride, tetramethylammonium borohydride; lithium hydride, sodium hydride , Calcium hydride and other alkali metal or alkaline earth metal hydrides; lithium methoxide, sodium ethoxide, calcium methoxide and other alkali metal or alkaline earth metal alkoxides; lithium phenoxide, sodium phenoxide, magnesium phenoxide Kishido, LiO-Ar-OLi, NaO-Ar-ONa (A
r 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, etc. Zinc compounds; boron oxide, boric acid, sodium borate, trimethyl borate, tributyl borate, triphenyl borate, (R ¹ R ² R ³ R ⁴ ) NB
Ammonium borates represented by ^{(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) phosphonium borates represented by (R ^1, R ² , R ³ , R ⁴
Is as described in Chemical Formula 1. ), Etc .; silicon compounds such as silicon oxide, sodium silicate, tetraalkylsilicon, tetraarylsilicon, diphenyl-ethyl-ethoxysilicon, etc .; germanium oxide, germanium tetrachloride, germanium ethoxide, germanium phenoxide, etc. Compounds of germanium: tin compounds such as tin oxide, dialkyltin oxide, dialkyltin carboxylate, tin acetate, ethyltin tributoxide, and other tin compounds combined with alkoxy or aryloxy groups, and tin compounds such as organotin compounds;
Lead compounds such as lead oxide, lead acetate, lead carbonate, basic carbonate, alkoxide or aryloxide of lead and organic lead; onium compounds such as quaternary ammonium salt, quaternary phosphonium salt and quaternary arsonium salt Antimony compounds such as antimony oxide and antimony acetate;
Manganese compounds such as manganese acetate, manganese carbonate and manganese borate; zirconium acetate, zirconium oxide, alkoxide or aryloxide of zirconium,
Catalysts such as zirconium compounds such as zirconium acetylacetone can be mentioned. 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 1 part by weight, preferably 10 to 10 parts by weight, based on 100 parts by weight of the aromatic dihydroxy compound as the raw material.
It is selected in the range of ^-7 to 10 ^-1 part by weight.

[0034]

Embodiments of the present invention will be described below in detail. -Moisture: Analyzed by Karl Fischer method. -Titanium content: Analyzed using ICP (high frequency inductively coupled plasma emission spectrometer; JY38PII manufactured by Seiko Instruments Inc.). O, p'-Bis (phenoxycarboxyl) biphenyl 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 high temperature is determined by heating the aromatic polycarbonate at 380 ° C. for 30 minutes in a nitrogen atmosphere,
The evaluation was based on the increase in absorbance of m.

Number average molecular weight (Mn): Measured by gel permeation chromatography (GPC) using tetrahydrofuran as a solvent {column: TSK-GEL, manufactured by Tosoh Corporation} and using standard monodisperse polystyrene. It was determined by using the reduced molecular weight calibration curve obtained by the following equation. 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.

[0036]

Example 1 After diphenyl carbonate was produced from dimethyl carbonate and phenol using tetraphenoxytitanium as a catalyst, the pressure was 1596 Pa, the number of distillation stages was 5, and the reflux ratio was 3.0. It was cut, purified by distillation, and stored in a SUS304 container under a nitrogen atmosphere at 110 ° C. for 100 hours. The water content of the diphenyl carbonate after storage was 0.1 wt ppm, the titanium content was 0.4 wt ppm, and the o, p'-bis (phenoxycarboxyl) biphenyl content was 0.1 wt ppm. 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 kept 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.

[0039]

Example 2 Except that the storage conditions were 145 ° 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 titanium content of 0.4 wt ppm, and o,
Using diphenyl carbonate having a p'-bis (phenoxycarboxyl) biphenyl content of 0.3 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 0.002.
Ninety-nine good color aromatic polycarbonates were obtained. The amount of increase in absorbance after heating the obtained aromatic polycarbonate at 380 ° C. for 30 minutes under a nitrogen atmosphere is 0.0006,
The decrease in the number average molecular weight was 300, and it was difficult to color even at a high temperature, and the molecular weight was hardly reduced.

[0040]

Example 3 Except that the storage conditions were changed to 165 ° C. and 800 hours, production, purification and storage were carried out in the same manner as in Example 1; water content: 0.1 wt ppm; titanium content: 0.4 wt ppm;
Using diphenyl carbonate having a p'-bis (phenoxycarboxyl) biphenyl content of 0.5 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 of 5 was obtained. After heating the obtained aromatic polycarbonate at 380 ° C. for 30 minutes under a nitrogen atmosphere, the amount of increase in absorbance was 0.0008,
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 hard to decrease.

[0041]

Embodiment 4 SUS3 whose inner wall surface has been washed with phenol
Except for storage in a container made of 04, manufactured, purified and stored in the same manner as in Example 3, water content 0.1 wtppm, titanium content 0.4 wtppm, o, p'-bis (phenoxycarboxyl) biphenyl content Using 0.2 wt ppm of diphenyl carbonate, 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 0.0028 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 0.0005, 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.

[0042]

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, titanium content 0.7 weight ppm, o, p'-
Bis (phenoxycarboxyl) biphenyl content 0.1
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 40033 at 400 nm and a good color. 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.

[0043]

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 wt ppm, titanium content 0.9 wt ppm, o, p '
-Bis (phenoxycarboxyl) biphenyl content
Using 1 ppm by weight of diphenyl carbonate, an aromatic polycarbonate was produced in the same manner as in Example 1 to obtain an aromatic polycarbonate having a number average molecular weight of 10,000 and an absorbance of 0.0038 at 400 nm and a good color. The obtained aromatic polycarbonate is treated at 380 ° C. under nitrogen atmosphere for 30 minutes.
After heating for one minute, the increase in absorbance was 0.0013, and the decrease in number average molecular weight was 900. Thus, coloring was difficult even at a high temperature, and the molecular weight did not easily decrease.

[0044]

Example 7 Except for storage in an atmosphere of 0.5% by volume of oxygen and 99.5% by volume of nitrogen, production, purification and storage were carried out in the same manner as in Example 1; water content: 0.1 wt ppm; titanium content: An aromatic polycarbonate was produced in the same manner as in Example 1 by using diphenyl carbonate having 0.4 wt ppm and o, p'-bis (phenoxycarboxyl) biphenyl content of 0.9 wt ppm, and having a number average molecular weight of 10,000 and 400.
A slightly colored aromatic polycarbonate with an absorbance at nm of 0.004 was obtained. After the obtained aromatic polycarbonate was heated at 380 ° C. for 30 minutes in a nitrogen atmosphere, the increase in absorbance was 0.002, and the decrease in number average molecular weight was 900.
It was difficult to be colored at high temperature, and the molecular weight was hardly reduced.

[0045]

Comparative Example 1 The same procedure as in Example 1 was carried out except that the product was not purified by distillation, the water content was 250 ppm by weight, and the titanium content was 1.
An aromatic polycarbonate was produced in the same manner as in Example 1 by using diphenyl carbonate having 5 ppm by weight and o, p'-bis (phenoxycarboxyl) biphenyl content of 0.1 ppm by weight, and having a number average molecular weight of 10,000 and 400 nm.
A colored aromatic polycarbonate having an absorbance of 0.0049 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 0.0037, 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. .

[0046]

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. The water content was 0.1 wt ppm and the titanium content was 0.4 wt. Aromatic polycarbonate was produced in the same manner as in Example 1 by using diphenyl carbonate having a ppm, o, p′-bis (phenoxycarboxyl) biphenyl content of 1.2 wt ppm, and a number average molecular weight of 10,000 and an absorbance of 40059 at 400 nm. 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
044, the amount of decrease in the number average molecular weight was 1,400, and coloring was easy at high temperatures, and the decrease in molecular weight was large.

[0047]

According to the present invention, a high-quality aromatic polycarbonate having good color, little coloration even at a high temperature of 380 ° C. or higher, 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 Outlet 7, 13, 15, 24, 33, 40, 50 Transfer piping 8, 16, 25, 34, 41 Supply 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

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4J029 AA10 BB12A BB12B BB12C BD08 BE07 BF14A BF14B BH01 BH02 DA10 DB11 DB13 HC05A HC05B HD03 HD05 KA02 KA03 KD02 KD09 KE05

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; b) the titanium content is not more than 1 ppm by weight;
(C) A method for producing an aromatic polycarbonate, wherein the content of o, p'-bis (phenoxycarboxyl) biphenyl is 1 ppm by weight or less. 2. A diaryl carbonate comprising: (a) a diaryl carbonate having a water content of 200 ppm by weight or less and (b) a diaryl carbonate having a titanium content of 1 ppm by weight or less,
2. 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 80 to 190 [deg.] C. under a nitrogen atmosphere in a stainless steel container. 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.