JP2002060481A - Method for manufacturing aromatic polycarbonate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an industrially preferred method for manufacturing a high quality aromatic polycarbonate which has a good color and, simultaneously, reduced discoloration even at a high temperature of >=380 deg.C and reduced lowering of the molecular weight in manufacturing the aromatic polycarbonate by the melt polycondensation method. SOLUTION: This method for manufacturing an aromatic polycarbonate by polymerizing an aromatic dihydroxy compound and a diaryl carbonate in a molten state comprises using, as the diaryl carbonate, the one having (a) a water content of <=200 wt.ppm, (b) a zinc content of <=1 wt.ppm, and (c) an o-phenylene carbonate content of <=2 wt.ppm.

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 phosgene method, which has been conventionally used, require the use of toxic phosgene at the time of production, residual chloride which affects the heat stability of the polycarbonate, mold corrosion during molding, and the like. It has problems such as containing methylene, and 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.

[0005] 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 high temperatures 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, there has been a strong demand for 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.

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 techniques are known.

For example, in Japanese Patent Application Laid-Open No. Hei 5-262873, the chlorine content based on chloroformate as an impurity contained in the carbonic diester is 30 ppm or less. In Japanese Patent Application Laid-Open No. Hei 6-179744, phenyl salicylate is used as the carbonic acid diester. , O-phenoxybenzoic acid and phenyl o-phenoxybenzoate are not substantially contained. JP-A-7-33866 discloses that a diaryl carbonate having a benzophenone derivative of 100 ppm or less is used, JP-A-7-62074. In the publication, 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; EP-06 The 7545A1 JP, salicylic acid derivatives, stannous ion, or the like using a carbonic acid diester without the one of methyl phenyl carbonate, defines a abundance of a particular compound in the diaryl carbonate.

In Japanese Patent Application Laid-Open No. 8-104747, the amount of an aromatic dihydroxy compound having a specific structure is 1%.
0 ppm by weight or more and 3% by weight or less;
No. 104748 discloses a specific bisphenol A derivative, a bisphenol A isomer, a chroman organic compound,
Total content of trisphenol I is 100 ppm or more and 10
Using bisphenol A that is not more than 00 ppm,
JP-A-11-310630 discloses the presence of a specific compound in an aromatic dihydroxy compound, 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. Specifies the amount.

However, these prior arts are not always enough to improve the color,
Even at the above-mentioned high temperatures, it was not possible to provide an aromatic polycarbonate with little coloration and little decrease in molecular weight.

[0011]

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.

[0012]

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 a method for producing an aromatic polycarbonate by polymerizing in a molten state from an aromatic dihydroxy compound and a diaryl carbonate,
The diaryl carbonate has (a) a water content of 200.
Weight ppm or less, and (b) zinc content is 1 weight ppm
(C) The method for producing an aromatic polycarbonate, wherein the content of o-phenylene carbonate is 2 ppm by weight or less.

In the present invention, the diaryl carbonate comprises (a) a water content of 200 ppm by weight or less;
(B) A diaryl carbonate having a zinc content of 1 ppm by weight or less is put in a stainless steel container, preferably a stainless steel container whose inner wall surface is wetted with phenol by a phenol treatment, under a nitrogen atmosphere. Preferably, it is a diaryl carbonate stored in the molten state at a temperature of 190 ° C.

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 intensive studies by the present inventors, water mixed by moisture absorption, zinc 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 aromatic polycarbonate product 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

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.

In the present invention, the aromatic dihydroxy compound is a compound represented by HO-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 a carbon number Represents a substituted or unsubstituted divalent alkane group having 1 to 30).

In the divalent aromatic groups Ar ¹ and Ar ² , at least one hydrogen atom has another substituent which does not adversely influence 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.

Preferred 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,
Is an organic group represented by

[0024]

Embedded image (Wherein, R ¹ , R ² , R ³ , and R ⁴ are each independently hydrogen, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, and cycloalkyl having 5 to 10 ring carbon atoms) A carbocyclic aromatic group having 5 to 10 carbon atoms and a carbocyclic aralkyl group having 6 to 10 carbon atoms, k represents an integer of 3 to 11, and R ⁵ and R ⁶ are each X And each independently represents hydrogen or an alkyl group having 1 to 6 carbons, X represents carbon, and R ¹ , R ² , R ³ , R ⁴ ,
In R ⁵ and R ⁶ , other substituents such as a halogen atom, for example, a halogen atom, so long as one or more hydrogen atoms do not adversely influence the reaction.
It may be substituted by 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, or the like. )

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

[0026]

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, Is 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
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).

[0029]

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.

[0033]

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

Ar^ThreeAnd Ar^FourIs a monovalent carbocyclic or
Represents an aromatic aromatic group, but this Ar ^Three, Ar^FourAt
One or more hydrogen atoms do not adversely affect the reaction
Substituents, for example, a halogen atom, an alkyl having 1 to 10 carbon atoms
A kill group, an alkoxy group having 1 to 10 carbon atoms, a phenyl group,
Phenoxy group, vinyl group, cyano group, ester group,
Even if it is substituted by
good. Ar^ThreeAnd Ar^FourMay be the same or different
It may be something.

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 represented by the following formula (5).

[0037]

Embedded image

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

[0039]

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 carbonate such as lower alkyl-substituted diphenyl carbonate 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 content of the diaryl carbonate is preferably 100 ppm by weight or less, more preferably 50 ppm by weight or less. The lower limit of the water content is not particularly limited, and the water content may be lower than 0.01 ppm by weight. The effect of improving 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 of 200 wt.
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 zinc content in the diaryl carbonate is 1 ppm by weight or less. When the zinc content is more than 1 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 for this is not clear, it is assumed that the presence of zinc acts catalytically on the coloring reaction and the molecular weight reduction reaction of the aromatic polycarbonate at high temperatures.

The zinc content of the diaryl carbonate is preferably 0.5 ppm by weight or less, more preferably 0.5 ppm by weight.
1 ppm by weight or less. The lower limit of the zinc content is not particularly limited, and the zinc content may be less than 0.001 ppm by weight, but the coloring of the aromatic polycarbonate at a high temperature even when the zinc content is less than 0.001 ppm by weight. And the effect of improving molecular weight reduction is small.

As a method for controlling the zinc content within the above range, when producing a diaryl carbonate, a zinc catalyst is not used at all, or after a diaryl carbonate is produced using a zinc catalyst, a distillation operation or a washing operation is performed. A method of reducing the content and the like can be mentioned. However, when the diaryl carbonate is produced without using any zinc 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 resulting 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, it is at most 0.2 ppm by weight. Also o-
The lower limit of the phenylene carbonate content is not particularly limited, and the o-phenylene carbonate content may be less than 0.01 wt ppm, but the aromatic polycarbonate may be less than 0.01 wt ppm even if the o-phenylene carbonate content is less than 0.01 wt ppm. Has little effect of improving coloring at high temperatures.

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-phenylene carbonate produced may increase. Stainless steel is the Stainless Steel Handbook 13
To 21 pages (published by Nikkan Kogyo Shimbun, 5th edition), such as martensitic, ferritic, austenitic, ferritic and austenitic stainless steels, usually containing 10 to 30% by weight of chromium as classified and classified. And Fe-based superalloys as shown in the table on page 547 of the Stainless Steel Handbook. As specific examples, SUS201,
SUS202, SUS304, SUS304L, SUS
316, SUS316L, SUS347, SUS40
5, SUS430, SUS403, SUS410, SU
S431, SUS440C, SUS630, Incoloy 800, Incoloy 801, Incoloy 802, Incoloy 807, Incoloy 901, LCN155, W54
5, V57, W545, D979, CG27, S590
And the like. A preferred example is SUS30
4, SUS304L, 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 o-phenylene carbonate produced can be particularly reduced. Although the reason is not clear, it is presumed that the removal of adsorbed oxygen on the stainless steel surface with phenol prevents the production of o-phenylene carbonate.

The storage is preferably carried out in a nitrogen atmosphere. When air, particularly oxygen, is mixed in the storage container, the amount of o-phenylene carbonate produced increases.

The storage temperature is preferably in the range of 80 to 190 ° C. 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 preferable storage temperature range is 85 to 160 ° C, and further preferably 90 to 1 ° C.
40 ° 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 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.

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, stirred tank type reactor, thin film reactor, centrifugal thin film evaporation reactor, surface renewal type twin screw kneading reactor, twin screw horizontal stirring reactor, wet wall type reactor, perforated plate type that polymerizes while free falling Reactor,
A perforated plate reactor with a wire or the like that polymerizes while being dropped along a wire is used, and a polymerizer alone or in combination thereof is used. The polymerization can be performed either in a batch system or a continuous system. In addition, as a device for adding a stabilizer, an additive, and the like while the aromatic polycarbonate is in a molten state after the polymerization, it is also a preferable method to use an extruder, a polymer mixer, or the like in combination with a polymerization device. 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 produced. By removing this compound 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 depends on the molecular weight, and it is 1,330 KPa
(10 mmHg) to normal pressure is preferable, and 2660 KPa (20 mmHg) or less, particularly 133
0 KPa (10 mmHg) or less is preferable, and 266 KP
a (2 mmHg) or less is more preferable.

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.

As the polymerization catalyst, those used in this field
Is not particularly limited as long as it is
Sodium hydroxide, potassium hydroxide, calcium hydroxide
Hydroxides of alkali metals or alkaline earth metals such as
Classes: Sodium borohydride, Tetramethyl borohydride
Alkali metal of hydride of boron such as luammonium
Salt, alkaline earth metal salt, quaternary ammonium salt; water
Lithium hydride, sodium hydride, calcium hydride
Any alkali metal or alkaline earth metal hydride
, Lithium methoxide, sodium ethoxide, cal
Alkali metal or alkaline earth such as sodium methoxide
Alkoxides of a class of metals; lithium phenoxide, nato
Lium phenoxide, magnesium phenoxide, Li
O-Ar-OLi, NaO-Ar-ONa (Ar is Ali
Alkali metal or alkaline earth metal
Aryloxides; lithium acetate, calcium acetate, ammonium chloride
Alkali metals or alkaline earths such as sodium benzoate
Metal salts of organic acids; zinc oxide, zinc acetate, zinc pheno
Zinc compounds such as oxides; boron oxide, boric acid, boric acid
Sodium citrate, trimethyl borate, tributyl borate,
Triphenyl borate, (R¹R^TwoR^ThreeR^Four) NB (R¹R^TwoR
^ThreeR^Four), An ammonium borate represented by (R)¹R^TwoR
^ThreeR^Four) PB (R¹R^TwoR^ThreeR^FourPhosphonium bo represented by)
Rate (R ¹, R^Two, R^Three, R^FourIs as described in Chemical Formula 1.
is there. Compounds of boron such as silicon oxide and silicic acid
Sodium, tetraalkyl silicon, tetraarylke
Silicon or diphenyl-ethyl-ethoxysilicon
Elemental compounds; germanium oxide, germanium tetrachloride
, Germanium ethoxide, germanium phenoxy
Compounds such as germanium; tin oxide, dialky
Rutin oxide, dialkyltin carboxylate, vinegar
Alkoxy groups such as tin oxalate and ethyltin tributoxide
Or a tin compound combined with an aryloxy group, an organotin
Tin compounds such as compounds; lead oxide, lead acetate, carbonic acid
Lead, basic carbonates, alkoxides of lead and organic lead or
Lead compounds such as aryloxide; quaternary ammonium
Salts, quaternary phosphonium salts, quaternary arsonium salts, etc.
Onium compounds: antimony oxide, antimony acetate
Antimony compounds such as manganese acetate, man carbonate
Manganese compounds such as cancer and manganese borate; acetic acid
Zirconium, zirconium oxide, zirconium al
Coxide or aryloxide, zirconium acetyla
Catalysts such as compounds of zirconium such as seton
I can do it.

When catalysts are 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.

[0063]

Embodiments of the present invention will be described below in detail. The measuring method in the example is as follows.

Water content was analyzed by the Karl Fischer method.

Zinc content: ICP (high frequency inductively coupled plasma emission spectrometer; JY38 manufactured by Seiko Instruments Inc.)
PII).

O-phenylene carbonate content: analyzed by gas chromatography.

Coloring: A solution prepared by dissolving 1 g of a sample in 7 ml of methylene chloride was placed in a cell having an optical path length of 1 cm, and the absorbance at 400 nm was measured with a spectrophotometer to obtain an index of coloring.

The ease of coloring at a high temperature can be 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): Measured by gel permeation chromatography (GPC) {column: TSK-GEL, manufactured by Tosoh Corporation} using tetrahydrofuran as a solvent, and using standard monodisperse polystyrene. It was determined by using the reduced molecular weight calibration curve obtained by the following equation.

[0070] 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 with which the molecular weight was reduced at high temperatures 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.

Example 1 After producing diphenyl carbonate from dimethyl carbonate and phenol using diphenoxyzinc as a catalyst, the gas phase in 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 3.0 was obtained. And then distilled and refined in a SUS304 container.
It was stored at 105 ° C. for 100 hours under a nitrogen atmosphere. Water content in diphenyl carbonate after storage 0.1 wt.
m, zinc content 0.4 wt ppm and o-phenylene carbonate content 0.1 wt ppm. Using the diphenyl carbonate, an aromatic polycarbonate was produced by a process as shown in FIG.

The first polymerization vessel 3 of the stirred tank type was operated in a batch manner, and the storage tank 10 and subsequent ones were continuously operated. Each of the stirring tank type polymerization vessels 3 (capacity 200 liters), 17 (capacity 50 liters), and 26 (capacity 50 liters) has a stirring blade. The horizontal twin-screw stirring type polymerization vessel 35 (capacity: 30 liters) has twin-screw stirring blades with L / D = 6 and a rotating diameter of 140 mm. The perforated plate type polymerization reactor 42 with a wire
A perforated plate 43 having 50 holes with a diameter of 5 mm is provided. A SUS316L wire 44 having a diameter of 1 mm is vertically suspended from the center of the hole to a liquid reservoir at the lower part of the polymerization vessel, and the height of the drop 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 fully degassed bisphenol A and the above-mentioned diphenyl carbonate (molar ratio of bisphenol A 1.10) were placed in a first polymerization vessel 3 of a stirred tank type.
7 mg of sodium hydroxide was charged and melt-mixed for 5 hours, and the molten polymer 5 having a number average molecular weight of 350 was 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 a transfer pump (plunger pump) 14. Stirred tank type 1
In the polymerization vessel 3, before the molten polymer 11 in the storage tank 10 runs out, a molten polymer having a number average molecular weight of 350 is produced by the same method 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.

The stirring tank type second polymerization vessel 17 has a reaction temperature of 23.
Under conditions of 5 ° C. and a reaction pressure of 13.3 MPa (100 mmHg), when the liquid volume of the molten polymer 20 reaches 20 liters, the stirring tank type third polymerization vessel 26 is kept at a constant number so as to keep the liquid volume at 20 liters. The molten polymer having a molecular weight of 850 was continuously supplied by a transfer pump (gear pump) 23.

The third polymerization reactor 26 of the stirring tank type has a reaction temperature of 24.
Under conditions of 5 ° C. and a reaction pressure of 798 KPa (6 mmHg), when the liquid volume of the molten polymer 29 reaches 20 liters, the horizontal twin-screw agitated polymerization vessel 35 is set to a number average molecular weight of 2300 so as to keep the liquid volume at 20 liters constant. Was continuously supplied by a transfer pump (gear pump) 32.

In the horizontal twin-screw polymerization reactor 35, the reaction temperature is 270 ° C. and the reaction pressure is 67 Pa. When the liquid volume of the molten polymer reaches 10 liters, a wire is attached so that the liquid volume is kept constant at 10 liters. A molten polymer having a number average molecular weight of 6,100 was supplied to the perforated plate type polymerization vessel 42 by a transfer pump (gear pump) 37.

In the perforated-plate type polymerization reactor 42 with a 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 number average molecular weight is 10,000 and 400 n from the outlet 51 through the transfer pipe 50 so as to maintain the liquid volume of 20 liters.
An aromatic polycarbonate having a good absorbance of 0.0027 m and a color of 0.0027 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.

Example 2 Storage conditions were 143 ° C., 300
Except for the time, it was produced, purified and stored in the same manner as in Example 1, with a water content of 0.1 wt ppm and a zinc content of 0.4 wt p
pm, o-phenylene carbonate content 0.3 weight pp
m diphenyl carbonate was used to produce an aromatic polycarbonate in the same manner as in Example 1, and the number average molecular weight was 10
An aromatic polycarbonate having an excellent absorbance at 000 and 400 nm and an absorbance of 0.0029 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. Was also difficult to wake up.

Example 3 Storage conditions were 167 ° C. and 800
Except for the time, it was produced, purified and stored in the same manner as in Example 1, with a water content of 0.1 wt ppm and a zinc content of 0.4 wt p
pm, o-phenylene carbonate content 0.8 wt pp
m diphenyl carbonate was used to produce an aromatic polycarbonate in the same manner as in Example 1, and the number average molecular weight was 10
An aromatic polycarbonate having a good color with an absorbance at 000 and 400 nm of 0.0034 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. Was also difficult to wake up.

(Example 4) The same procedure as in Example 3 was carried out except that the inner wall surface was stored in a SUS304 container having been subjected to a phenol-cleaning treatment.
m, an aromatic polycarbonate was produced in the same manner as in Example 1 using diphenyl carbonate having a zinc content of 0.4 wt ppm and an o-phenylene carbonate content of 0.4 wt ppm, and having a number average molecular weight of 10,000 and an absorbance of 400 nm. 0028 excellent aromatic polycarbonate 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. Was also difficult to wake up.

Example 5 The number of distillation stages was 3, and the reflux ratio was 0.
Except that it was 8, produced, purified and stored in the same manner as in Example 1.
Water content 20 wtppm, zinc content 0.7 wtppm,
Using diphenyl carbonate having an o-phenylene carbonate content of 0.1 wt ppm, an aromatic polycarbonate was produced in the same manner as in Example 1, and the number average molecular weight was 1,000.
An aromatic polycarbonate having good color and an absorbance of 0.0033 at 0 and 400 nm was obtained.

After the aromatic polycarbonate obtained was heated at 380 ° C. for 30 minutes in a nitrogen atmosphere, the increase in absorbance was 0.0009, and the decrease in number average molecular weight was 700. Was also difficult to wake up.

Example 6 The number of distillation stages was 3, and the reflux ratio was 0.
Except that it was 1, manufactured, purified and stored in the same manner as in Example 1,
Water content 150 weight ppm, zinc content 0.9 weight pp
m, o-phenylene carbonate content 0.1 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.
An aromatic polycarbonate having good color and an absorbance of 0.0038 at 00 and 400 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 0.0013, and the decrease in number average molecular weight was 900. Was also difficult to wake up.

(Example 7) Oxygen 0.5% by volume, nitrogen 9
Except for storage under an atmosphere of 9.5% by volume, it was manufactured, purified and stored in the same manner as in Example 1;
m, an aromatic polycarbonate was produced in the same manner as in Example 1 using diphenyl carbonate having a zinc content of 0.4 wt ppm and an o-phenylene carbonate content of 1.8 wt ppm, and having a number average molecular weight of 10,000 and an absorbance of 400 nm. A slightly colored aromatic polycarbonate of 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 0.0019, and the decrease in number average molecular weight was 900. Was also difficult to wake up.

(Comparative Example 1) Example 1 was conducted except that purification by distillation was not performed.
Aromatic polycarbonate was produced in the same manner as in Example 1 by using diphenyl carbonate produced and stored in the same manner as in Example 1 and using 250 ppm by weight of water, 1.5 ppm by weight of zinc and 0.1 ppm by weight of o-phenylene carbonate. , Number average molecular weight 10,000, absorbance at 400 nm
0048 of a colored aromatic polycarbonate were obtained.

After the obtained aromatic polycarbonate was heated at 380 ° C. for 30 minutes in a nitrogen atmosphere, the increase in absorbance was 0.0036, and the decrease in number average molecular weight was 1500. Was also big.

(Comparative Example 2) Production was performed in the same manner as in Example 1 except that the mixture was stored in an atmosphere of 2% by volume of oxygen and 98% by volume of nitrogen.
Using purified and stored diphenyl carbonate having a water content of 0.1 wt ppm, a zinc content of 0.4 wt ppm, and an o-phenylene carbonate content of 2.4 wt ppm,
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 0.005.
8 colored aromatic polycarbonates were obtained.

After the obtained aromatic polycarbonate was heated at 380 ° C. for 30 minutes in a nitrogen atmosphere, the increase in absorbance was 0.0043, and the decrease in number average molecular weight was 1,400. Was also big.

[0097]

As described above, according to the present invention, a high-quality aromatic polycarbonate having good color, less 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. Can be manufactured.

[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 AB05 AB07 AC01 AC02 AD01 AD10 BB10A BB10B BB12A BB12B BB12C BB13A BB13B BD09A BD09B BD09C BE07 BG07X BG08X BG08Y BG24X BH01 JA01 DBH31 JA01 JB171 JC091 JC631 JC711 JC731 JC751 JF021 JF031 JF041 JF131 JF141 JF181 JF331 JF361 JF371 JF381 JF471 JF541 KA03 KD01 KD07 KD09 KE05 LA06 LA10 LB01

Claims (3)

[Claims] 1. A method for producing an aromatic polycarbonate by polymerizing an aromatic dihydroxy compound and a diaryl carbonate in a molten state, wherein the diaryl carbonate has (a) a water content of 200 ppm by weight or less, and (b) A zinc content of 1 ppm by weight or less; (c)
A process for producing an aromatic polycarbonate, wherein the content of o-phenylene carbonate is 2 ppm by weight or less. 2. A diaryl carbonate having a water content of 200 ppm by weight or less and (b) a zinc content of 1 ppm by weight or less in a stainless steel container in a nitrogen atmosphere under a nitrogen atmosphere of 80 to 190 wt. 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 ° C. 3. The method for producing an aromatic polycarbonate according to claim 2, wherein the stainless steel container is a container whose inner wall surface has been subjected to a washing treatment with phenol.