JPH10139876A - Method for producing aromatic polycarbonate - Google Patents

Abstract

(57) [Problem] To obtain a high molecular weight aromatic polycarbonate excellent in quality such as hue and heat aging resistance. SOLUTION: In producing a polycarbonate using a carbonic acid diester / aromatic diol compound as a monomer, the resulting prepolymer has a viscosity average molecular weight of 10,000.
In the reaction stage of the polymerization tank reaching 0, the total molar ratio of each monomer consumed in the reaction in the polymerization tank before the polymerization tank and the unreacted monomer contained in the polymer in the polymerization tank (diester carbonate / dicarbonate) Aromatic diol compound)
Is controlled so as to be 1.010 to 1.050.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for continuously producing an aromatic polycarbonate using a plurality of polymerization tanks while controlling the supply amounts of the raw materials of the aromatic diol compound and the carbonic acid diester.

[0002]

2. Description of the Related Art Aromatic polycarbonate is a resin excellent in various strengths and excellent in transparency, and is used in a wide range of fields. As an industrial production method of this polycarbonate, an interfacial polymerization method in which bisphenol A and phosgene are reacted in a methylene chloride solvent is generally used, but this method requires the use of phosgene or methylene chloride which is industrially difficult to handle. Therefore, in recent years, without using these compounds, a method of producing a polycarbonate by transesterifying a carbonate diester such as diphenyl carbonate and an aromatic diol compound such as bisphenol A in a molten state without a solvent has been proposed, Some have been put to practical use.

[0003] In the reaction between diphenyl carbonate and bisphenol A, the viscosity of the reaction mixture increases as the molecular weight of the produced polymer (aromatic polycarbonate) increases. Therefore, this reaction is usually carried out using a multi-stage polymerization tank. (JP-A-2-153925,
No. 6-1557739). However, in each polymerization tank, it is necessary to carry out the reaction while discharging phenol by-produced by the transesterification reaction to the outside of the system. At this time, a small amount of the reaction raw material (monomer) is also discharged together with a small amount. There is a risk. Therefore, usually, diphenyl carbonate, which is a component on the side with a large amount of loss, is supplied to the first polymerization tank so as to exceed the stoichiometric ratio. However, the amount of raw monomer loss fluctuates depending on the reaction conditions such as the amount of catalyst, temperature, pressure, blade rotation speed, etc., or even if continuous operation is performed under the same reaction conditions, depending on the specifications of the phenol by-product discharge section. As a result, the physical properties of the finally obtained polymer fluctuate. In particular, when the ratio of diphenyl carbonate decreases, the hydroxyl group concentration at the polymer terminal increases, and it is difficult to obtain a polymer having good heat aging resistance.

There are some proposals for producing aromatic polycarbonates having excellent physical properties such as hue and heat aging resistance, but they are not always satisfactory.
For example, in Japanese Unexamined Patent Publication (Kokai) No. 6-1557739, a polymer having an intrinsic viscosity [η] of 0.2 at the inlet of the reactor is used.
A method is disclosed in which the reaction is added to at least one of the reactors having a dl / g (equivalent to a viscosity average molecular weight of 7,400) or more. In this method, the reaction is carried out under substantially high temperature and high vacuum conditions. Therefore, the ratio of the added terminator actually contributing to the reaction of the polymer terminal is apt to fluctuate, and there is a problem in stably controlling the amount of terminal hydroxyl groups. Only a polycarbonate having a hydroxyl group concentration can be obtained. JP-A-7-82368 discloses a method in which at least one monomer of a dihydroxy compound and a carbonic acid diester is sequentially added. However, it is only necessary to increase the molecular weight of the produced polymer and to optimally control the amount of terminal groups. No satisfactory product has been obtained in quality.

In Japanese Patent Application Laid-Open No. 3-252421, when the number average molecular weight (Mn) of the aromatic polycarbonate reaches 1,000 to 10,000 during the reaction for the purpose of controlling the terminal group weight and the molecular weight, Weight of aromatic polycarbonate (Wa), number average molecular weight (M
n), the ratio of hydroxyl group terminals to all terminal groups (OH%) and the ratio of aryl carbonate terminals (Ph
%), And when OH% is higher than a desired value, a predetermined amount of diaryl carbonate is added. When OH% is lower than a desired value, a predetermined amount of a dihydroxydiaryl compound is added. By doing so, the desired OH
A production method for obtaining a polycarbonate having% and Mn has been proposed. However, in this method, it is necessary to control the polymerization while analyzing the polymer generated during the reaction, and when the polymerization conditions fluctuate due to some fluctuations in the process operation, it is not possible to respond flexibly, and the method is stable. It is difficult to control the terminal group weight and the molecular weight.

[0006] Similarly, in JP-A-8-109251, similarly, the ratio of the OH group to the aryl carbonate terminal group in the intermediate carbonate produced is measured in a timely manner, followed by further addition of an aromatic dihydroxy compound or carbonate. Introduce diarylester to increase terminal OH groups to greater than 25% and 50%
Production methods have been proposed in which a certain ratio of OH end groups to aryl carbonate end groups is empirically established in the range below and further condensed. However, even in this method, it is necessary to analyze the polymer during the reaction, and monitoring by on-line infrared spectrum analysis measurement as shown in the patent publication lacks accuracy and cannot be sufficiently controlled.

Further, in Japanese Patent Application Laid-Open No. Hei 8-113637, the amount of by-product phenols or alcohols produced is continuously measured, and the temperature is 100 to 280 ° C. and the pressure is 10
After controlling the temperature and pressure in the range of Torr to 5 kg / cm ² G to produce a polycarbonate prepolymer,
Although a method for producing a polycarbonate by further reacting this is disclosed, a method for controlling the terminal group weight and the molecular weight to be satisfactory in quality is not disclosed here.

[0008]

SUMMARY OF THE INVENTION According to the present invention, when synthesizing an aromatic polycarbonate using diphenyl carbonate and bisphenol A using a multi-stage polymerization tank, the polymerization conditions are controlled by simple indices, and the hue and heat resistance are controlled. An object of the present invention is to provide a method for obtaining an aromatic polycarbonate having excellent aging properties and the like.

[0009]

Means for Solving the Problems The present inventors have conducted various studies in view of the above-mentioned circumstances, and as a result, have found that the amount of diphenyl carbonate, which is accompanied by loss of phenol by-produced, fluctuates more than expected. Focusing on the amount of the raw material monomer supplied to the first polymerization tank and the relationship between the amount of diphenyl carbonate lost in each polymerization tank and the hydroxyl group concentration at the polymer terminal, the viscosity average molecular weight of the produced polycarbonate prepolymer was 10,10. In the reaction stage of the polymerization tank reaching 000, the sum of each monomer consumed in the reaction in the polymerization tank before (including the polymerization tank) and the unreacted monomer contained in the polymer in the polymerization tank By controlling the molar ratio of, a condition for obtaining a polymer of stable quality was found, and the present invention was completed.

That is, the present invention provides an aromatic diol compound and a diester carbonate as monomers for a reaction raw material.
In the presence of a transesterification catalyst, the reaction is carried out using a plurality of polymerization tanks arranged in series, whereby the viscosity average molecular weight becomes 1
In a method for continuously producing 5,000 or more aromatic polycarbonates, in a reaction stage of a polymerization tank in which a viscosity average molecular weight of a produced polycarbonate prepolymer reaches 10,000, the reaction is consumed in a reaction in a polymerization tank before the polymerization tank. The total molar ratio (carbonic acid diester / aromatic diol compound) of each of the obtained monomers and the unreacted monomers contained in the polymer in the polymerization tank is 1.010 to 1.05.
Characterized in that it is controlled so as to be 0 and reacted.
An object of the present invention is to provide a method for producing an aromatic polycarbonate.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the method for producing an aromatic polycarbonate of the present invention will be described more specifically.
In the present invention, an aromatic diol compound and a carbonic acid diester are used as raw materials (monomers) for producing an aromatic polycarbonate. Aromatic diol compound: The aromatic diol compound used in the production of the present invention is a compound represented by the general formula (1).

[0012]

Embedded image

(Wherein A is a single bond, a substituted or unsubstituted linear, branched or cyclic divalent hydrocarbon group having 1 to 10 carbon atoms, and -O-, -S-, -CO -, -SO _2- , selected from the group consisting of divalent groups represented by
And Y are the same or different and are selected from halogen or a hydrocarbon group having 1 to 6 carbon atoms, and p and q are 0 or an integer of 1 to 2. )

Some representative examples include, for example, bis (4-hydroxyphenyl) methane, 2,2-bis (4
-Hydroxyphenyl) propane, 2,2-bis (4-
(Hydroxy-3-methylphenyl) propane, 2,2-
Bis (4-hydroxy-3-t-butylphenyl) propane, 2,2-bis (4-hydroxy-3,5-dimethylphenyl) propane, 2,2-bis (4-hydroxy-
3,5-dibromophenyl) propane, 4,4-bis (4
-Hydroxyphenyl) heptane, 1,1-bis (4-
Bisphenols such as hydroxyphenyl) cyclohexane; biphenols such as 4,4'-dihydroxybiphenyl, 4,4'-dihydroxy-3,3 ', 5,5'-tetramethylbiphenyl; bis (4-hydroxyphenyl) sulfone , Bis (4-hydroxyphenyl) sulfide, bis (4-hydroxyphenyl) ether, bis (4-hydroxyphenyl) ketone and the like. Among these, 2,2-bis (4-hydroxyphenyl) propane is preferable.

Two or more of these compounds can be used in combination (copolymer). When a branched aromatic polycarbonate is to be produced, a small amount of a trihydric or higher polyhydric phenol is copolymerized. You can also.

Carbonic acid diester; examples of the carbonic acid diester include dimethyl carbonate, diphenyl carbonate,
Examples include ditolyl carbonate, bis (4-chlorophenyl) carbonate, and bis (2,4,6-trichlorophenyl) carbonate.

Transesterification catalyst: In a melt polymerization reaction between an aromatic diol compound and a carbonic acid diester,
A transesterification catalyst is used. As such a transesterification catalyst, an alkali metal compound, an alkaline earth metal compound, a quaternary ammonium salt, and a phosphonium salt are used. Specific examples of such an alkali metal compound and an alkaline earth metal compound include alkali metal compounds. And organic acid salts, inorganic acid salts, oxides, hydroxides, hydrides or alcoholates of alkaline earth metals.

More specifically, the alkali metal compounds include sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium hydrogen carbonate, potassium hydrogen carbonate, lithium hydrogen carbonate, sodium carbonate, potassium carbonate, lithium carbonate, bisphenol A Disodium salt, dipotassium salt, dilithium salt, phenol sodium salt, potassium salt and lithium salt. In addition, cesium hydroxide, cesium carbonate, inorganic cesium salts such as cesium hydrogen carbonate, cesium acetate, organic acid cesium salts such as cesium stearate, cesium methylate, cesium alcoholate such as cesium ethylate, cesium phenolate, bisphenol A of bisphenol A And cesium salts of phenols such as cesium salts.

Further, as the alkaline earth metal compound, specifically, calcium hydroxide, barium hydroxide,
Examples include magnesium hydroxide, strontium hydroxide, calcium hydrogen carbonate, barium hydrogen carbonate, magnesium hydrogen carbonate, strontium hydrogen carbonate, calcium carbonate, barium carbonate, magnesium carbonate, strontium carbonate, and the like. These compounds are used alone or in combination.

In the present invention, a basic compound can be used as a catalyst together with the above-mentioned alkali metal compound and / or alkaline earth metal compound. Such basic compounds include, for example, nitrogen-containing basic compounds and phosphonium hydroxy compounds which are easily decomposable or volatile at high temperatures, rarely remain in the final aromatic polycarbonate, and do not adversely affect physical properties such as hue. And specifically, the following compounds.

Examples of the nitrogen-containing basic compound include ammonium hydroxides having an alkyl, aryl, araryl group and the like such as tetramethylammonium hydroxide (Me ₄ NOH) and tetraethylammonium hydroxide (Et ₄ NOH), trimethylamine, triethylamine Secondary amines represented by R ₂ NH (where R is an alkyl group such as methyl and ethyl, and an aryl group such as phenyl and toluyl);
Primary amines represented by NH ₂ (wherein R is as defined above), imidazoles such as 2-methylimidazole and 2-phenylimidazole, iminocarboxylic acid derivatives such as sodium nitrilotriacetate or salts thereof, or ammonia , tetramethyl ammonium borohydride (Me ₄ NBH _4), basic salts such as tetrabutylammonium borohydride (Bu ₄ NBH ₄₎ and the like.

Examples of the phosphonium hydroxide compound include tetraethylphosphonium hydroxide, tetrabutylphosphonium hydroxide, tetraphenylphosphonium hydroxide, methyltriphenylphosphonium hydroxide, allyltriphenylphosphonium hydroxide and the like.

In the case of an alkali metal compound and / or an alkaline earth metal compound, the amount of the catalyst used is usually from 1 × 10 ^-8 to 1 per mol of the aromatic diol compound.
It is used in an amount of × 10 ^-4 mol, preferably 1 × 10 ^-7 to 1 × 10 ^-5 mol. In the case of a basic compound, 1 × 10 ^-4 mol is usually used per 1 mol of the aromatic diol compound. ^-7 to 1
It is used in an amount of × 10 ^-1 mol, preferably 1 × 10 ^-6 to 1 × 10 ^-2 mol.

Next, a method for producing an aromatic polycarbonate according to the present invention will be described. In the present invention, any apparatus can be used as a reaction apparatus used for the reaction of the polymer. Normally, turbine blades, paddle blades, anchor blades, full zone blades (manufactured by Shinko Pantech Co., Ltd.), Sun Meller blades (manufactured by Mitsubishi Heavy Industries, Ltd.), Max Blend blades (manufactured by Sumitomo Heavy Industries, Ltd.), helical ribbons One or two or more vertical polymerization tanks equipped with blades, twisted lattice blades (manufactured by Hitachi, Ltd.), etc., followed by a horizontal uniaxial polymerization tank such as a disk type or a cage type, and HVR, SCR, N- SCR (Mitsubishi Heavy Industries, Ltd.), Vivolac (Sumitomo Heavy Industries, Ltd.)
Manufactured), glasses wings, lattice wings (Hitachi, Ltd.)
) Can be used in combination.

FIG. 1 shows an example of an apparatus used in the continuous polymerization method of the present invention. Bisphenol A is used as an example of an aromatic diol as a monomer of a reaction raw material, and diphenyl carbonate is used as an example of a diester carbonate compound. It will be described using FIG.

In FIG. 1, five polymerization tanks are installed in series. In the figure, 1 is a raw material introduction pipe, 2 is a transesterification catalyst introduction pipe, 3 is a by-product discharge pipe, 4, 4 ', 4 "and 4'" are vertical polymerization tanks, 5, 5 'and 5 ". Is a Max Blend stirring blade, and 6 is a double helical ribbon blade. Also,
Reference numeral 7 denotes a schematic horizontal sectional view of the horizontal polymerization tank. Reference numerals 8 and 9 denote lattice blades (the lattice blades 8 and 9 intersect at right angles). Reference numeral 10 denotes a first prepolymer extraction tube. Reference numeral 11 denotes a second prepolymer. A polymer outlet tube, 12 is a third prepolymer outlet tube, 13 is a fourth prepolymer outlet tube, and 14 is a final product polymer outlet tube.

In the reaction, first, a molten mixture of bisphenol A as an aromatic diol compound and diphenyl carbonate as a carbonic acid diester is introduced into the first polymerization tank 4 through a raw material introduction pipe 1 under an atmosphere of an inert gas such as nitrogen gas. And an alkali metal compound as a catalyst and / or
Alternatively, an alkaline earth metal compound and / or a basic compound is continuously supplied into the above-mentioned polymerization tanks through the catalyst introduction pipes 2, and in each polymerization tank, phenol by-produced is removed from the by-product discharge pipes 3. Meanwhile, the polymerization is carried out using three to seven stages of polymerization tanks (five units in FIG. 1).

The reaction conditions are as follows: temperature: 150 to 320
° C, pressure: normal pressure to 0.01 Torr, average residence time: 5
In each polymerization tank, in order to make the discharge of phenol by-produced with the progress of the reaction more effective, stepwise, within the above reaction conditions, at a higher temperature and a higher vacuum. Set to. In order to prevent deterioration of the hue and the like of the obtained polycarbonate, it is preferable to set the temperature as low as possible and the residence time as low as possible.

The ratio of diphenyl carbonate and bisphenol A supplied to the first polymerization tank is not particularly limited, but is usually in the range of 1.010 to 1.200. In the method of the present invention, in the reaction stage of the polymerization tank (the fourth tank in Examples 1 to 5) in which the viscosity average molecular weight of the produced prepolymer reaches 10,000, the polymerization tank before the polymerization tank (Example: (1 to 4 tanks), and the total ratio of the unreacted monomer contained in the polymer in the polymerization tank and the unreacted monomer contained in the polymer in the polymerization tank (carbonic acid diester / aromatic diol compound) is 1.010 to 1.0. It should be within the range of 050, preferably in the range of 1.020 to 1.050, and more preferably in the range of 1.020 to 1.045. In the reaction stage of the polymerization tank in which the viscosity average molecular weight of the produced polycarbonate prepolymer reaches 10,000, the monomers consumed in the reaction in the polymerization tank before the polymerization tank and the unreacted substances contained in the polymer in the polymerization tank If the total molar ratio of each monomer is less than 1.010, the viscosity average molecular weight is 15,000.
Even if the polymerization is advanced to the above-mentioned predetermined molecular weight, the hydroxyl group concentration at the terminal of the produced aromatic polycarbonate is not sufficiently reduced, and the quality such as heat aging resistance is inferior. On the other hand, if the molar ratio of these two components is more than 1.050, the reaction does not easily proceed, so that it takes a long time to reach a predetermined viscosity average molecular weight, and it is necessary to raise the polymerization temperature. ,For this reason,
The hue of the aromatic polycarbonate obtained is not good either.

The prepolymer has a viscosity average molecular weight of 10.0
Reaching to 00 is usually achieved in the third and subsequent polymerization tanks. In the reaction stage of the polymerization tank in which the viscosity average molecular weight of the produced prepolymer reaches 10,000, the monomer consumed in the reaction in the polymerization tank before the polymerization tank and the unreacted monomer contained in the polymer in the polymerization tank, respectively In order to control the total molar ratio (carbonic acid diester / aromatic diol compound) within the above range, in the entire polymerization area involved in the reaction until the viscosity average molecular weight is reached, the total amount of diphenyl carbonate and bisphenol A Supply amount [Measurement preparation; $ DPC (IN)
And ΣBPA (IN)] and the respective total losses (according to the measurement of the amount of effluent and its composition analysis; ΣDPC (OUT) and ΣBPA (OUT)) By understanding, the molar ratio of the monomer unit is calculated by the following formula:

[0031]

(Equation 1)

When the molar ratio is out of the above-mentioned control range, an additional component monomer is usually supplied additionally in the first polymerization tank. Adjustment is made by batch or divided supply in the tank and additional supply so that it is stable within the control range. Therefore, in order to minimize the loss of components other than phenol such as diphenyl carbonate, the multi-tube cylindrical type, double-tube type, coil type, spiral type, etc. Heat exchanger,
Alternatively, a condenser of a tray type, a packed tower type, or the like may be arranged as auxiliary equipment.

The prepolymer has a viscosity average molecular weight of 15.0
In order to reach the predetermined molecular weight of 00 or more, the reaction may be further advanced using polymerization tanks arranged in series, but the viscosity average molecular weight is higher than the polymerization tank at the time of reaching 10,000. In the subsequent polymerization tank, the amount of monomer loss is so small as to be almost negligible, so there is no need to consider the control range. The aromatic polycarbonate having a viscosity average molecular weight of 15,000 or more discharged from the final polymerization tank has a hue YI of 1.8 or less and a terminal hydroxyl group concentration of 1,4.
500 ppm or less, preferably 10 to 1,000 pp
It is a polymer which is excellent in quality such as hue and heat aging resistance.

The aromatic polycarbonate obtained in the present invention may be added to a conventional heat stabilizer, ultraviolet absorber, release agent, antistatic agent, slip agent, antiblocking agent, lubricant, antifogging agent, natural oil, synthetic oil, Additives such as wax, organic fillers and inorganic fillers may be added. Such an additive can be added to the aromatic polycarbonate in a molten state, or can be added by remelting the aromatic polycarbonate once pelletized. Note that remelting is preferably performed in an inert gas atmosphere.

[0035]

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples. The obtained aromatic polycarbonate was analyzed by the following measurement method. (1) Viscosity-average molecular weight (Mv) Using a Ubbelohde viscometer, the intrinsic viscosity [η] at 20 ° C. in methylene chloride was measured.
v) was determined. [Η] = 1.23 × 10 ⁻⁴ × (Mv) ^0.83

(2) Hue Using an injection molding machine J100SS-2 (manufactured by Nippon Steel Works), a square sheet having a thickness of 3 mm, a length of 100 mm and a width of 100 mm was obtained at a barrel temperature of 280 ° C. and a mold temperature of 90 ° C. Was injection molded. About this injection molded sheet,
Color tester (SC-1-C manufactured by Suga Test Instruments Co., Ltd.)
In (H), the tristimulus value XYZ, which is the absolute value of the color, was measured, and the YI value, which is an index of yellowness, was calculated by the following relational expression. YI = (100 / Y) × (1.28X-1.06Z) The larger the YI value, the more colored.

(3) Terminal hydroxyl group concentration Titanium tetrachloride / acetic acid method (Makromol. Chem. 88 , 215 (196)
Colorimetry was performed according to 5)). (4) Heat aging resistance The degree of hue deterioration of the injection-molded sheet after holding it for 240 hours in a gear oven (manufactured by TABAI) controlled at 140 ° C. in an air atmosphere is represented by ΔYI value (difference from initial YI value). ). Further, the total ratio of the monomer consumed in the polymerization in the polymerization tank before the polymerization tank and the unreacted monomer contained in the polymer in the polymerization tank, that is, the molar ratio of the monomer unit (DPC / BPA)
(Molar ratio) was specifically calculated according to the following equation.

[0038]

(Equation 2)

The composition analysis of DPC and BPA in the effluent was performed by gas chromatography (HEWLETT PACKARD 58).
90 Series II).

Example 1 In a nitrogen gas atmosphere, bisphenol A and diphenyl carbonate were mixed at a constant molar ratio (DPC / BPA molar ratio =
1.040) together with the adjusted melt mixture.
A first vertical stirring polymerization tank having a capacity of 100 L, equipped with the Max Blend impeller shown in FIG. 1 at a flow rate of 1.064 mol / h through a raw material introduction pipe and controlled at 210 ° C. under normal pressure and nitrogen atmosphere. The liquid level was kept constant while controlling the opening of a valve provided in the polymer discharge line at the bottom of the tank so that the average residence time was 30 minutes. At the same time as starting the supply of the raw material mixture, 2
A weight percent aqueous cesium carbonate solution was continuously supplied at a flow rate of 3.2 ml / hour (1 × 10 ⁻⁶ mol per mol of bisphenol A). The polymerization liquid discharged from the bottom of the tank continues to the second, third, and fourth (second and third tanks: Max blend blades,
Fourth tank: Double helical ribbon blade) 100 L vertical stirring polymerization tank and 150 L horizontal polymerization tank equipped with a fifth lattice blade are sequentially and successively supplied to the polymer outlet at the bottom of the fifth polymerization tank. The polycarbonate extracted from the sample was devolatilized and cooled, and then pelletized.

During the reaction, the liquid level was controlled so that the average residence time in each of the second to fifth polymerization tanks was 60 minutes.
At the same time, phenol by-produced was distilled off. At this time, the discharge amount of bisphenol A and diphenyl carbonate from 3 shown in FIG. 1 was measured. The reaction conditions in each of the second to fifth polymerization tanks are as follows.
00 Torr, 110 rpm), the third polymerization tank (240
° C, 15 Torr, 75 rpm), the fourth polymerization tank (270
C, 0.5 Torr, 25 rpm), the fifth polymerization tank (28
(0 ° C., 0.5 Torr, 10 rpm), conditions were set to high temperature, high vacuum, and low stirring speed as the reaction progressed. The viscosity average molecular weights of the respective polymers extracted from the third, fourth and fifth polymerization tanks at the time when each tank was stabilized stably were 4,800, 12,000 and 20,400, respectively.
At this time, the total molar ratio of the monomer consumed in the reaction in the polymerization tank before the fourth polymerization tank where the viscosity average molecular weight reached 10,000 and the unreacted monomer contained in the polymer in the polymerization tank (DPC / BPA) is 1.
0251 and a viscosity average molecular weight of 15,000.
The hue YI of the polycarbonate extracted from the fifth polymerization tank was 1.5 and the terminal hydroxyl group concentration was 940 ppm.
Met.

Example 2 In Example 1, the molten mixture in which the molar ratio of bisphenol A and diphenyl carbonate was adjusted to 1.060 (DPC / BPA) was adjusted to 404.996 mol /
Example 1 was repeated except that the mixture was continuously supplied to the first polymerization tank at the flow rate at the time.
The reaction was carried out under the same reaction conditions as described above to obtain a polycarbonate. The viscosity average molecular weights of the polymers extracted from the third, fourth and fifth polymerization tanks at the time when each tank was stabilized stably were 4,700, 10,300 and 18,100, respectively. At this time, the total ratio of the monomer consumed in the reaction in the polymerization tanks before the fourth polymerization tank whose viscosity average molecular weight reached 10,000 and the unreacted monomer contained in the polymer in the polymerization tank (DPC / BPA) is 1.0425
The hue YI of the polycarbonate extracted from the fifth reaction vessel having a viscosity average molecular weight of 15,000 or more was 1.4, and the terminal hydroxyl group concentration was 410 ppm.

COMPARATIVE EXAMPLE 1 In Example 1, 397.132 mol / mol of the melt mixture obtained by mixing and adjusting the molar ratio of bisphenol A to diphenyl carbonate to 1.020 (DPC / BPA) was used.
Example 1 was repeated except that the mixture was continuously supplied to the first polymerization tank at the flow rate at the time.
The reaction was carried out under the same reaction conditions as described above to obtain a polycarbonate. The viscosity average molecular weights of the polymers extracted from the third, fourth, and fifth polymerization tanks at the time when each tank was stably stabilized were 4,900, 13,400, 22,100, respectively. Molar ratio (DPC / BPA) of the total of the monomer consumed in the reaction in the polymerization tank before the fourth polymerization tank before the viscosity average molecular weight reached 10,000 and the unreacted monomer contained in the polymer in the polymerization tank Is 1.0073,
In addition, the fifth type having a viscosity average molecular weight of 15,000 or more.
The hue YI of the polycarbonate extracted from the polymerization tank was 1.6, and the terminal hydroxyl group concentration was 1,760 ppm. Although the viscosity average molecular weight was high, a polycarbonate having a sufficiently reduced terminal hydroxyl group concentration could not be obtained.

Examples 3 to 5 and Comparative Example 2 In Comparative Example 1, the monomers consumed in the reaction in the polymerization tanks before the fourth polymerization tank in which the viscosity average molecular weight reached 10,000 and the polymer in the polymerization tank were added. For the purpose of controlling the total ratio (DPC / BPA) of each of the unreacted monomers contained within the control range, diphenyl carbonate melted at 110 ° C. was introduced into the second to fourth polymerization tanks at a flow rate shown in Table 2. The polymerization was carried out under the same reaction conditions as in Comparative Example 1 except that additional supply was carried out to obtain a polycarbonate. Table 2 shows the polymerization conditions and the results.

Comparative Example 3 In Example 1, the melt mixture obtained by mixing and adjusting the molar ratio of bisphenol A to diphenyl carbonate to 1.075 (DPC / BPA) was combined with 305.959 mol / mol.
The reaction was carried out under the same reaction conditions as in Example 1 except that the mixture was continuously supplied to the first polymerization tank at the flow rate at the time, and the average residence time was 40 minutes in the first polymerization tank and 80 minutes in each of the second to fifth polymerization tanks. Then, a polycarbonate was obtained. At the time when each tank is stabilized stably,
The viscosity average molecular weights of the polymers extracted from the third, fourth, and fifth polymerization tanks are 5,300, 10,200, and 1,300, respectively.
It was 5,400. At this time, the viscosity average molecular weight was 10,
000, and the total ratio of the monomers consumed in the reaction in the polymerization tanks before the fourth polymerization tank and the unreacted monomers contained in the polymer in the polymerization tank (DPC /
(BPA) was 1.0576, and the hue YI of the polycarbonate extracted from the fifth polymerization tank having a viscosity average molecular weight of 15,000 or more was 2.3, and the terminal hydroxyl group concentration was 140 ppm. Although the terminal hydroxyl group concentration was low, the reaction took a long time to reach a predetermined viscosity average molecular weight, so that the hue YI was reduced.

Table 1 shows the polymerization conditions of Examples 1 to 5 and Comparative Examples 1 to 3, and Table 2 shows the DPC / BPA molar ratio, the viscosity average molecular weight of the prepolymer, and the physical properties of the produced polycarbonate. Show.

[0047]

[Table 1]

[0048]

[Table 2]

[0049]

According to the production of the aromatic polycarbonate according to the present invention, a high molecular weight aromatic polycarbonate having excellent quality such as hue and heat aging resistance can be obtained.

[Brief description of the drawings]

FIG. 1 is a flow sheet diagram of the manufacturing method of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Raw material introduction pipe 2 Catalyst introduction pipe 3 By-product discharge pipe 4 Vertical polymerization tank 5 Stirrer blade 7 Horizontal polymerization tank 10 Prepolymer extraction pipe 14 Final polymer extraction pipe

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor, Katsushige Hayashi 2-4-1-16 Hinagahigashi, Yokkaichi City, Mie Prefecture Inside Yokkaichi Plant, Sanrishi Gas Chemical Co., Ltd. 2-4-1-16 Sanyo Gas Chemical Co., Ltd. Yokkaichi Plant

Claims (4)

[Claims] 1. An aromatic diol compound as a reaction raw material monomer and a carbonic acid diester are reacted in the presence of a transesterification catalyst using a plurality of polymerization tanks arranged in series, whereby the viscosity average molecular weight is 15,000. In the above method for continuously producing an aromatic polycarbonate, in the reaction stage of the polymerization tank in which the viscosity average molecular weight of the produced polycarbonate prepolymer reaches 10,000, each of the components consumed in the reaction in the polymerization tank before the polymerization tank is used. The reaction is performed by controlling the total molar ratio of the monomer and the unreacted monomer contained in the polymer in the polymerization tank (carbonic acid diester / aromatic diol compound) to be 1.010 to 1.050. A method for producing an aromatic polycarbonate. 2. A flow rate of the carbonic acid diester and the aromatic diol compound supplied to the polymerization tank or the transfer pipe, and a discharge of the carbonic acid diester and the aromatic diol compound contained in the distillate discharged from the polymerization tank during the reaction operation. Measure the amount and molar ratio (carbonic acid diester / aromatic diol compound)
The method according to claim 1, wherein: 3. The method according to claim 1, wherein the number of polymerization tanks is 3 to 7. 4. The method according to claim 1, wherein the aromatic diol compound is bisphenol A and the carbonic acid diester is diphenyl carbonate.