JPH07268090A - Production of polycarbonate - Google Patents

Abstract

PURPOSE:To provide a production process wherein the diameters of the dispersed liquid drops in the emulsion are specified in the reaction, the coalescence and dispersion of the dispersed liquid drops are repeated to thereby accomplish the reaction within a short time, and a high-quality polycarbonate can be produced at a low production cost. CONSTITUTION:This production process is the one comprising reacting a polycarbonate oligomer with a dihydric phenol, which process comprises step A of introducing a mixture of an organic solvent solution of the polycarbonate oligomer with an alkaline aqueous solution of the dihydric phenol into a dispersion zone to form an emulsion having a diameter of a dispersed liquid drop of 100mum or below, step B of introducing the formed emulsion into an coalescence zone where the dispersed liquid drops coalesce for the dispersed liquid drops to coalesce and repeating a combination of steps A and B.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a polycarbonate, and more specifically, in the case of producing a polycarbonate by an interfacial polycondensation method, a reaction time is shortened and the production cost is reduced to obtain a high quality polymer. The present invention relates to a method for producing a polycarbonate.

[0002]

2. Description of the Related Art Generally, polycarbonate resins are widely produced by a so-called interfacial polycondensation method by reacting a dihydric or trihydric or higher polyhydric phenol with phosgene in the presence of an alkali. Regarding this interfacial polycondensation method, conventionally, various methods have been investigated in both batch method and continuous method, and as a method for efficiently producing a polycarbonate by the interfacial polycondensation method and obtaining a polymer having excellent quality, For example, there are methods described in JP-B-52-36554, JP-A-1-278528, and the like.

[0003]

However, in the production of polycarbonate by the interfacial polycondensation method including the above-mentioned method, the reaction between the chloroformate group (CF group) derived from phosgene and the hydroxyl group in the condensation reaction of the polycarbonate is not possible. If sufficient, CF groups remain, which decompose during thermoforming to generate hydrochloric acid, which adversely affects product quality. In order to suppress the above-mentioned drawbacks, it is attempted to prolong the reaction time in order to suppress the remaining CF group. However, if the reaction time is long, it takes a long time to switch the grades, which is efficient in polymer production. Not. In addition, there is a problem that the manufacturing cost becomes high because a large reactor is required.

[0004]

As a result of intensive studies in view of the above problems, the present inventors have paid attention to the droplet diameter of the emulsion formed during the reaction, set this as a specific value, and The present invention has been completed by finding that the reaction can be completed in a short time by repeating the above, and a high quality polycarbonate can be obtained. The droplets of such an emulsion are described in JP-A-4-266925, but there is no clear disclosure about the above-mentioned coalescence / dispersion, and the reaction time is a long time exceeding 2 hours. is there. There is no report on the relationship between the droplet size of the emulsion formed during the reaction as in the present invention and the reaction.

That is, the present invention relates to (1) a method of producing a polycarbonate by reacting a polycarbonate oligomer with a dihydric phenol, wherein a mixed solution of a solution of the polycarbonate oligomer in an organic solvent and an alkaline aqueous solution of the dihydric phenol is used. Step (A) of introducing the emulsion solution into the dispersion zone so that the diameter of the dispersion droplet becomes 100 μm or less, and introducing the emulsion solution into the coalescence zone where the dispersion droplets coalesce to form the dispersion droplet. A method for producing a polycarbonate, which comprises the step (B) of bringing together, and the reaction is carried out by repeating the steps (A) and (B), (2) a polycarbonate oligomer and a dihydric phenol In the method for producing a polycarbonate by reacting, a solution of a polycarbonate oligomer in an organic solvent and two Mixed solution of an aqueous alkaline solution of phenol was introduced into the line mixer, dispersed droplets diameter 10
It comprises a step (A) of forming an emulsion solution having a particle size of 0 μm or less and a step (B) of introducing the emulsion solution into a coalescence tank to coalesce the dispersed droplets thereof. And (3) are repeated to carry out the reaction.
The residence time of the mixed solution in the step (A) and the step (B) is 30 minutes or less, the method for producing a polycarbonate according to the above (1) or (2), (4) a polycarbonate oligomer and a dihydric phenol. In the method for producing a polycarbonate by reacting with a group of compounds, a mixed solution of a solution of a polycarbonate oligomer in an organic solvent and an aqueous alkali solution of a dihydric phenol is introduced into a line mixer to obtain a dispersion droplet diameter of 100 μm or less. As a solution, at least a part of the emulsion solution from the line mixer is introduced into the coalescence tank to coalesce the dispersed droplets of the emulsion solution, and then the coalesced emulsion solution is recycled into the line mixer. A method for producing a polycarbonate, characterized in that A method for producing a polycarbonate by reacting a turbo sulfonate oligomer dihydric phenols, a mixed solution of an aqueous alkaline solution of an organic solvent solution and dihydric phenols of the polycarbonate oligomer,
Introduced into a line mixer installed in two or more stages in series,
The diameter of dispersed droplets is 100 at each line mixer outlet.
Production of a polycarbonate, characterized in that an emulsion solution having a size of less than or equal to μm is used, and the residence time between each line mixer is set to 1 minute or more to cause the dispersed droplets in the emulsion solution to coalesce and to carry out the reaction. In the method, (6) a method of producing a polycarbonate by reacting a polycarbonate oligomer and a dihydric phenol, a part of a mixed solution of a solution of the polycarbonate oligomer in an organic solvent and an alkaline aqueous solution of the dihydric phenol is used in a reactor. Introduced into the mixer installed in the reactor,
An emulsion solution having a dispersed droplet diameter of 100 μm or less is prepared, and the emulsion solution from the mixer is circulated in the reactor to coalesce the dispersed droplets of the emulsion solution, and then the coalesced emulsion solution is A method for producing a polycarbonate, characterized in that an emulsion solution containing the same is recycled in the mixer to carry out a reaction, and (7) the emulsion is a water / oil type emulsion, wherein the above-mentioned (1) to (6) The method for producing a polycarbonate according to any one of 1) to 10).

The present invention will be described in more detail below. INDUSTRIAL APPLICABILITY In the production of polycarbonate (hereinafter sometimes abbreviated as PC), the present invention allows the reaction to proceed for a short time by setting the dispersed droplet diameter at the interfacial polycondensation reaction to 100 μm or less and repeating coalescence and dispersion. It is a method for producing a polycarbonate by which the reaction is completed to obtain a high-quality polycarbonate. In the present invention, a mixed solution of an organic solvent solution of a polycarbonate oligomer and an alkaline aqueous solution of a dihydric phenol is used as an emulsion solution having a dispersed droplet diameter of 100 μm or less in the step (A) including a dispersion zone. When the diameter of the dispersed droplets of the emulsion solution exceeds 100 μm, it is difficult to complete the reaction within a short time of 30 minutes, which is not preferable. It is preferable that the emulsion has a uniform droplet diameter over the entire reaction zone, and that the droplets are in a state of repeating coalescence and dispersion. Here, the dispersed droplet diameter indicates the average body area diameter on the dispersed phase side, and can be measured by sampling the emulsion and observing it with an optical microscope.

The droplets have a predetermined stirring power of the mixed solution or emulsion, that is, Pv of 0.1 kW / m ³ or more,
Preferably, it can be formed by stirring at 0.5 kW / m ³ or more. A stirring tank may be used to obtain such stirring power, but for example, the following line mixer is preferable in terms of efficiency. Pipeline homomixer (Special Kika Kogyo Co., Ltd.)
Made by Homomic Line Flow (Special Kika Kogyo Co., Ltd.)
Multi-line mixer (Satake Chemical Machinery Co., Ltd.)
Komatsu Sruzer Disintegrator (manufactured by Komatsu Zenoa Co., Ltd.) High Mixer (manufactured by Toray Co., Ltd.) Sulzer Mixer (Sumitomo Heavy Industries, Ltd.)
Kenix Static Mixer (Noritake Co., Ltd.) Orifice mixer

In the above reaction, if stirring power is not applied during the reaction, coalescence of the droplets progresses and the droplet diameter cannot be maintained. Therefore, in the present invention, for example, as shown in FIG. 2, (a) a method of using two or more mixers in multiple stages ((a) of FIG. 2), (b) a method of recycling the reaction mixture to the mixer. ((B) of FIG. 2) or (C) a method of providing the mixer in the reactor ((C) of FIG. 2) is preferably used to provide stirring. Specifically, as the method (a), for example, there is a mode in which two or more mixers are arranged in series and a pot or the like is arranged as a coalescing tank between the mixers. Also, (b)
In the method of (1), a single mixer that can give the required stirring power and a uniting tank such as a pot are provided in the recycling line as a uniting zone, or a means such as piping that can secure the required residence time is provided. Thus, a mode in which the reaction mixture is recycled can be mentioned. Further, as the method of (c), for example, a mixer having a required stirring power is provided in a mixed solution of a reactor containing a mixed solution of an organic solvent solution of a polycarbonate oligomer and an alkaline aqueous solution of a dihydric phenol, An example is a mode in which the mixed solution is circulated while continuously passing through a mixer to give a stirring power to make the inside of the reactor a coalescence zone.

On the other hand, in the present invention, in order to prevent the emulsion droplets from becoming finer during the reaction and making separation / purification difficult at the time of polymer recovery after the reaction, the emulsion solution is dispersed in the droplets. Is introduced into the coalescence zone where they coalesce, and a step (B) of coalescing the droplets is provided. Such coalescence of the liquid droplets can be performed by a method of retaining the droplets in a coalescence tank such as a pot or by appropriately securing retention time between the mixers. The conditions for dispersion and unity are:
Although it may be appropriately determined according to the degree of progress of the reaction, it is generally preferable to carry out the dispersion and coalescence twice or more, and the residence time for coalescence during stirring is 1 minute to allow sufficient coalescence to proceed. The above is preferable. Further, the coalescence is preferably performed in a laminar flow state. The above methods (b) and (c) are efficient because the dispersion and coalescence can be continuously performed. In the present invention, either the aqueous phase or the organic solvent phase may be a dispersed phase during the reaction, but coalescence easily proceeds and a sufficient amount of the required amount of dihydric phenol can be dissolved in the aqueous phase side. Therefore, it is preferable that the water / oil type emulsion, that is, the dispersed phase is an aqueous phase.

Since the interfacial polycondensation reaction of PC is an exothermic reaction, the reaction temperature is preferably 0 to 50 ° C., preferably 10 to 40 ° C. Such heat removal can be carried out by various conventionally known methods such as a method in which each raw material including PC oligomer is cooled in advance and the sensible heat thereof is used, and a method in which a reactor is provided with a jacket for cooling. When the method (b) is used, a method of providing a cooler in the recycling line is preferable in terms of efficiency. When the reaction temperature is higher than 50 ° C., decomposition of CF groups and side reactions due to the reaction increase, which is not preferable.

The reaction of the present invention can be completed by the above-mentioned method including the steps (A) and (B), but in order to further complete the reaction, a reactor such as a stirring tank or a pot is provided in the latter stage. You can The reaction mixture obtained can be recovered as a polymer by a known method after separating the organic solvent phase and the aqueous phase and washing to make a clear polycarbonate solution. Further, the obtained polymer can be further added with various additives or mixed with other resins to prepare a final product. That is, if desired, a heat stabilizer, a hindered phenol-based antioxidant, a phosphite-based antioxidant, an amine-based antioxidant, a benzotriazole-based antioxidant,
UV absorbers such as benzophenone series, light stabilizers such as hindered amine series, external lubricants such as aliphatic carboxylic acid ester series, paraffin series, flame retardants, flame retardant aids, release agents, antistatic agents, colorants, etc. You may mix | blend various additives, and also fillers, such as glass fiber, and various polymers.

A preferred example of the manufacturing method of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a schematic process drawing showing a preferred embodiment of the manufacturing method of the present invention. According to FIG. 1, PC oligomer A, dihydric phenol B, catalyst C optionally added, alkaline aqueous solution D and organic solvent E are introduced into the dispersion zone, that is, the step (A), and the line mixer 1 is used. An emulsion solution having a dispersed droplet diameter of 100 μm or less is prepared, the valve 6 is adjusted, and a necessary amount of the emulsion solution is introduced into the coalescence zone, that is, step (B) to coalesce the dispersed droplets in the coalescence tank 2. Then, the obtained emulsion solution is recycled to the step (A) again and the dispersed droplet diameter is adjusted to 100 μm or less by the line mixer 1. By repeating this, the reaction is performed, and after the reaction is completed, the obtained PC is introduced from the valve 6 into the final reaction tank 7 which is provided as needed, and additives and the like are added to further complete the reaction. After this, Polycarbonate F can be obtained.

The PC oligomer used in the method for producing a polycarbonate of the present invention can be generally synthesized using an aromatic dihydric phenol or an aliphatic dihydric hydroxy compound and phosgene in the presence of an alkali. There are various aromatic dihydric phenols used in the present invention, and examples thereof include compounds represented by the following general formula (I).

[0014]

[Chemical 1]

--O--, --CO--, --S--, --SO-- or --SO _2- , wherein R ¹ and R ² are each a hydrogen atom,
It is a monovalent hydrocarbon group or a halogen atom, R ³ and R ⁴ are hydrogen atoms or a monovalent hydrocarbon group, respectively, and R ⁵ is a divalent hydrocarbon group. Further, m and n each represent an integer of 1 to 4. )

Specific examples of such compounds include bis (4-hydroxyphenyl) methane; 1,1-bis (4
-Hydroxyphenyl) ethane; 2,2-bis (4-hydroxyphenyl) propane (commonly called bisphenol A); 2,2-bis (4-hydroxyphenyl) butane; 2,2-bis (4-hydroxyphenyl) octane; 2,2-bis (4-hydroxyphenyl) phenylmethane; 2,2-bis (4-hydroxy-1-methylphenyl) propane; 1,1-bis (4-hydroxy-t)
-Butylphenyl) propane; 2,2-bis (4-hydroxy-3-bromophenyl) propane; 2,2-bis (4-hydroxy-3,5-tetramethylphenyl) propane; 2,2-bis (4 -Hydroxy-3-chlorophenyl) propane; 2,2-bis (4-hydroxy-)
3,5-Tetrachlorophenyl) propane; 2,2-bis (4-hydroxy-3,5-tetrabromophenyl)
Bis (hydroxyaryl) alkanes such as propane, 1,1-bis (4-hydroxyphenyl) cyclopentane; 1,1-bis (4-hydroxyphenyl) cyclohexane; 1,1-bis (4-hydroxyphenyl)
Bis (hydroxyaryl) cycloalkanes such as -3,5,5-trimethylcyclohexane, 4,4-dihydroxydiphenyl ether; dihydroxyaryl ethers such as 4,4'-dihydroxy-3,3'-dimethylphenyl ether, 4 , 4'-dihydroxydiphenyl sulfide; 4,4'-dihydroxy-3,
Dihydroxydiaryl sulfides such as 3'-dimethyldiphenyl sulfide, 4,4'-dihydroxydiphenyl sulfoxide; 4,4'-dihydroxy-3,
Dihydroxyaryl sulfoxides such as 3′-dimethyldiphenyl sulfoxide; 4,4′-dihydroxydiphenyl sulfone; 4,4′-dihydroxy-3,
Examples thereof include dihydroxydiaryl sulfones such as 3′-dimethyldiphenyl sulfone.

There are various kinds of aliphatic dihydric hydroxy compounds. For example, butane-1,4-diol; 2,2-dimethylpropane-1,3-diol;
Hexane-1,6-diol; diethylene glycol;
Triethylene glycol; tetraethylene glycol;
Octaethylene glycol; dipropylene glycol;
N, N-methyldiethanolamine; cyclohexane-
1,3-diol; cyclohexane-1,4-diol; 1,4-dimethylolcyclohexane; p-xylylene glycol; 2,2-bis- (4-hydroxycyclohexyl) -propane and ethoxy of dihydric alcohol or phenol Or propoxylation products such as bis-oxyethyl-bisphenol A; bis-oxyethyl-tetrachlorobisphenol A or bis-
Oxyethyl-tetrachlorohydroquinone and the like can be mentioned.

Among the above-mentioned aromatic dihydric phenols or aliphatic dihydric hydroxy compounds, bisphenol A (BPA) is most preferable from the viewpoint of balance of physical properties of products and cost. Further, in order to impart heat resistance and flame retardancy to the polymer, trivalent or higher phenols may be used, or halogenophenols may be used to form an oligomer. Furthermore, monohydric phenols may be added and reacted in order to control the molecular weight.

Examples of such monohydric phenols include o
-N-butylphenol; m-n-butylphenol;
p-n-butylphenol; o-isobutylphenol; m-isobutylphenol; p-isobutylphenol; o-t-butylphenol; m-t-butylphenol; p-t-butylphenol; o-n-pentylphenol; m-n- Pentylphenol; p-n-pentylphenol; on-hexylphenol; m-
n-hexylphenol; pn-hexylphenol; o-cyclohexylphenol; m-cyclohexylphenol; p-cyclohexylphenol; o-phenylphenol; m-phenylphenol; p-phenylphenol; on-nonylphenol; m- n-
Nonylphenol; pn-nonylphenol; o-cumylphenol; m-cumylphenol; p-cumylphenol; o-naphthylphenol; m-naphthylphenol; p-naphthylphenol; 2,6-di-t-butylphenol 2,5-di-t-butylphenol;
2,4-di-t-butylphenol; 3,5-di-t-
Butylphenol; 2,5-dicumylphenol; 3,
5-dicumylphenol; formula

[0020]

[Chemical 2] As a compound represented by or a chroman derivative, for example,
formula

[0021]

[Chemical 3]

Examples include monohydric phenols such as Of these phenols, pt-butylphenol; p-cumylphenol; p-phenylphenol and the like are preferably used in the present invention. The PC oligomer can be produced by adding an organic solvent that dissolves the oligomer to the dihydric phenol and an aqueous alkaline solution of the monohydric phenol that is optionally used, and then blowing phosgene into the organic solvent. . Examples of the phosgene or phosgene derivative used in the above reaction include phosgene, triphosgene, bromophosgene, and bis (2,4,6-
Examples thereof include trichlorophenyl) carbonate, bis (2,4-dichlorophenyl) carbonate, bis (2-cyanophenyl) carbonate, and trichloromethyl chloroformate.

As the organic solvent, in addition to methylene chloride which is usually preferably used, for example, a chlorine-based solvent such as chloroform and chlorobenzene, a solvent such as dioxane and tetrahydrofuran, or a mixed solvent thereof can be used. These solvents may contain a poor solvent to the extent that the polymer does not precipitate. As such a poor solvent,
For example, aromatic compounds such as benzene, toluene and xylene, alkanes such as pentane, hexane, heptane and octane, ketones such as acetone and methyl ethyl ketone,
Alternatively, mixed solvents thereof may be mentioned, but methylene chloride (MC) is most preferable from the viewpoints of cost and availability.

The PC oligomer used in the present invention preferably has a number average molecular weight of 400 to 5,000, particularly preferably 500 to 4,000, and has a CF group concentration of 0.05 to 3.0 mol / liter. Especially 0.1-2.5
It is preferably mol / liter. If the number average molecular weight of the PC oligomer is less than 400, it is necessary to react a larger amount of dihydric phenol during the condensation reaction, which is not efficient, and if it exceeds 5000, the viscosity of the organic solvent phase becomes high. It is not preferable because it is difficult to form the droplet size. Further, when the CF group concentration exceeds 3.0 mol / liter, the heat generation of the reaction becomes large, so that it is difficult to sufficiently remove the heat, and when the CF group concentration is less than 0.05, the reaction rate decreases and the reaction time becomes longer than necessary. It becomes long and is not desirable

In the present invention, the CF group in the PC oligomer and the alkaline solution of the dihydric phenol are subjected to a condensation reaction to obtain a polycarbonate. As the alkali used, a strong alkali such as sodium hydroxide or potassium hydroxide is suitable. The dihydric phenol may be the same as or different from the one used in the production of the PC oligomer, but bisphenol A (B
PA) is preferably used. Further, in the present invention, it is preferable to add a small amount of a reducing agent such as hydrosulfite in order to prevent the deterioration of the solution. The amount of the dihydric phenol used may be about the same mole as the CF group in the PC oligomer, but in general, the CF group concentration / OH group concentration is 0.9 to 1.5 mol / mol, preferably 1.0. ~ 1.5 mol / mol. If this value is less than 0.9, CF groups tend to remain in the polymer, which is unfavorable for quality. If it exceeds 1.5, a large amount of dihydric phenol remains in the emulsion after the reaction, making separation and purification difficult. Is not preferable.

In the above reaction, it is preferable to use a catalyst in order to promote the reaction smoothly. Examples of usable catalysts include tertiary amines and quaternary ammonium salts, and specifically, triethylamine, tri-n-butylamine,
Examples include diethylaminopyridine and tetramethylammonium chloride. In the present invention, triethylamine (TEA) is particularly preferable. In the production method of the present invention, an alkali, an organic solvent or the like can be added separately. Since the alkali is supplied as an aqueous solution of dihydric phenol as described above, it is not always necessary to supply it separately, but the amount consumed by the decomposition of CF groups during the reaction is replenished,
Alternatively, it may be added for the purpose of maintaining the optimum pH during the reaction. Further, an organic solvent may be added separately for the purpose of lowering the viscosity of the system, but in consideration of the recovery of the solvent, it is preferable to use the same one as used for the oligomer production.

[0027]

EXAMPLES The present invention will be described more specifically below with reference to synthesis examples, examples and comparative examples. Synthesis Example 1 Production of PC Oligomer Bisphenol A (B
PA) was dissolved and adjusted to a concentration of 14.5% by weight. 40 liters / hour of this aqueous solution, 25% by weight of para-tert-butylphenol (PTBP) as a molecular weight regulator
A methylene chloride (MC) solution at a flow rate of 0.35 liters / hr and MC as a solvent at a flow rate of 18.5 liters / hr at 20 ° C.
Was introduced into a tubular reactor having an inner diameter of 6 mm and a length of 30 m immersed in the cooling tank, and phosgene was blown thereinto at a flow rate of 3.8 kg / Hr. The reaction liquid at the outlet is separated in a stationary separation tank
The phase C side was used as a PC oligomer. When the properties of the oligomer were measured, the number average molecular weight measured by a vapor pressure osmometer (VPO) was 820, and the CF group concentration was 0.72 mol /
It was liter.

Example 1 As shown in FIG. 1, the PC oligomer prepared in Synthesis Example 1 was dissolved in a caustic soda aqueous solution of 20 liter / Hr and 6% by weight to dissolve BPA as a dihydric phenol to a concentration of 14.5% by weight. The prepared aqueous solution was 11.5 L / Hr, and a 4 wt% aqueous solution of triethylamine (TEA) as a catalyst was 0.0.
4 L / Hr, 25 wt% caustic soda aqueous solution as an aqueous alkaline solution 0.8 L / Hr, and MC as an organic solvent at a flow rate of 13 L / Hr and an internal volume of 0.3
T.L. with 43 liters and 43φ and 48φ turbine blades.
K. It was supplied to a pipeline homomixer 2SL type (made by Tokushu Kika Kogyo Co., Ltd.) and polymerization was carried out at a rotation speed of 3000 rpm. The reaction mixture at the outlet of the pipeline homomixer was recycled to the inlet of the pipeline homomixer at a flow rate of 50 liter / Hr by a pump through a pot as a coalescence tank. When a part of the reaction mixture at the outlet of the pipeline homomixer was sampled and the phase of the emulsion was confirmed, it was water / oil type and the average droplet diameter of the dispersed phase formed was 38 μm. . When the average residence time was calculated from the pipe volume,
It was 18 minutes. Further, a reaction mixture in an amount equal to that of the supplied raw materials was received in a pot as a final reaction tank having a residence time of 5 minutes, then overflowed and taken out, and an aqueous phase was separated as a reaction finished product, and then the pH was adjusted to 13.5. The polymer solution was repeatedly washed using an aqueous solution of caustic soda, an aqueous solution of hydrochloric acid whose pH was adjusted to 1.5 and pure water. A white polycarbonate powder was obtained from the obtained clear polymer solution by pulverizing while evaporating MC which is a solvent. The viscosity average molecular weight (Mv) of the polycarbonate powder was 29800. The amount of chlorine derived from the CF groups remaining in the polymer was measured and found to be 1
It was below ppm and the residual OH group amount at the terminal was 0.5%, which was excellent in quality.

Examples 2 to 5 The same as Example 1 except that the agitation rotation speed of the pipeline homomixer and the average residence time by changing the recycling amount of the reaction mixture were changed as shown in Table 1. Each was carried out. As shown in Table 1, the obtained polycarbonate was excellent in quality as in Example 1. Comparative Examples 1 to 3 were carried out in the same manner as in Example 1 except that the stirring rotation speed of the pipeline homomixer and the average residence time by changing the recycling amount of the reaction mixture were changed as shown in Table 1. . In Comparative Example 2 and Comparative Example 3, the reaction mixture from the pipeline homomixer was directly received in a pot having a residence time of 55 minutes without being recycled, and the same operation was performed. The results are shown in Table 1.

[0030]

[Table 1]

* 1 Pv (kW / m ³ ): Calculated by the following formula. Pv = (ρ · n ³ / gc) × Np × (d ⁵ / F) ρ: Liquid density (kg / m ³ ) n: Rotational speed (rps) Np: Power number (-) (2SL type is the first turbine Is 1.4
The second turbine is 0.8) d: Turbine diameter (m) gc: Gravity conversion factor (kgm / kg · sec ² ) F: Total flow rate (m ³ / Hr) * 2 Droplet diameter (μm): Emulsion It was measured by taking a photograph with a microscope. * 3 Residence time (min): Calculated from the reactor and pipe volumes and the total flow rate until the raw materials were mixed and sampled.

[0032]

[Table 2]

* 4 Residual chlorine content (ppm by weight): The polymer was dissolved in MC, 4-p-nitrobenzyl-pyridine was added, and the absorbance was measured. * 5 Terminal OH group amount (%): Determined from the amount of absorbed protons using a nuclear magnetic resonance apparatus. * 6 Molecular weight: Using an Ubbelohde type viscous tube, the MC solution viscosity at 20 ° C. was measured to obtain the intrinsic viscosity [η] and calculated by the following formula. [Η] = 1.23 × 10 ⁻⁵ × Mv ^0.83 * 7 Aqueous phase separation time (min): The reaction mixture was added with 5 times the amount of MC.
The time when the amount of the separated aqueous phase reached 100% (calculated value) was calculated. * 8 Indicates the case where the above aqueous phase separation time takes 60 minutes or more.

Example 6 The reaction was carried out in the same manner as in Example 1, except that the addition amounts of the raw materials were the same and three pipeline homomixers 1 of the reactor were connected in series as shown in FIG. A pot 2 having a residence time of 5 minutes was provided at the outlet of each reactor to allow the reaction to proceed. The residence time calculated from the volume of the reactor and the pipe was 18 minutes, and the average droplet diameter of the reaction mixture at the outlet of each of the first, second, and third homomixers was 53 μm.
m, 42 μm and 28 μm. The viscosity average molecular weight (Mv) of the obtained polycarbonate is 28800.
The residual chlorine amount is 1 ppm or less, and the residual amount of the terminal OH group is
It was 1.2%, which was excellent in quality.

Examples 7 and 8 The same procedure as in Example 6 was carried out except that the rotation speed of each mixer was changed as shown in Table 2. As shown in Table 2, the obtained polycarbonate had excellent quality as in Example 6. Comparative Examples 4 to 6 Comparative Example 4 was performed in the same manner as in Example 6 except that the pot was bypassed and operated, and Comparative Example 5 was similarly performed except that the second and third mixers were stopped. Comparative Example 6 was carried out in the same manner except that the number of revolutions was changed as shown in Table 2. The results are shown in Table 2.

[0036]

[Table 3]

[0037]

[Table 4]

Example 9 In Example 1, the reactor as shown in FIG.
A homomixer with a turbine diameter of 99.6 mm (made by Tokushu Kika Kogyo Co., Ltd.) in a tank equipped with a 0 liter jacket 10.
The stirring tank 9 in which 1 was inserted in the vertical direction was used. At the upper part of the homomixer, there is a liquid flow-back plate 12, and the raw material is supplied from the lower part of the tank and overflowed from the upper part. The rotation speed of the stirrer was 3600 rpm, and the average residence time was 4.5 minutes calculated from the volume. The average droplet diameter was 95 μm at the reactor outlet. The viscosity average molecular weight (Mv) of the obtained polymer was 27400, the residual chlorine amount was 1 ppm or less, and the residual amount of terminal OH groups was 0.8%. Further, when the separability of the reaction mixture was examined, the time taken for the entire aqueous phase to separate was 10 minutes, and there was no problem at all.

[0039]

As described above, the reaction is completed in a short time by setting the droplet size of the emulsion formed during the reaction to a specific value and repeating coalescence / dispersion as in the production method of the present invention. It is possible to reduce the manufacturing cost and obtain a high quality polycarbonate.

[Brief description of drawings]

FIG. 1 is a schematic process drawing showing one embodiment of a manufacturing method of the present invention.

FIG. 2 is a diagram showing an example of a stirring system for carrying out the manufacturing method of the present invention.

3 is a schematic process diagram showing a reactor used in Example 6. FIG.

FIG. 4 is a schematic sectional view showing a reactor used in Example 9.

[Explanation of symbols]

 1 Line Mixer 2 Combined Tank 3,6 Valve 4 Pump 5 Cooler 7 Final Reaction Tank 8 Reactor 9 Stirring Tank 10 Jacket 11 Homomixer 12 Liquid Flowback Plate A PC Oligomer B Divalent Phenol C Solvent D Alkaline Aqueous Solution E Organic Solvent F Polycarbonate G Raw material

Claims (7)

[Claims] 1. A method for producing a polycarbonate by reacting a polycarbonate oligomer and a dihydric phenol, wherein a mixed solution of an organic solvent solution of the polycarbonate oligomer and an alkaline aqueous solution of the dihydric phenol is introduced into a dispersion zone to disperse the mixture. A step (A) of forming an emulsion solution having a droplet diameter of 100 μm or less, and a step (B) of introducing the emulsion solution into a coalescence zone where the dispersed droplets coalesce to coalesce the dispersed droplets. The method for producing a polycarbonate, comprising the steps of: (A) and (B). 2. A method for producing a polycarbonate by reacting a polycarbonate oligomer with a dihydric phenol, wherein a mixed solution of an organic solvent solution of the polycarbonate oligomer and an alkaline aqueous solution of the dihydric phenol is introduced into a line mixer for dispersion. The above-mentioned step (A) comprises the step (A) of forming an emulsion solution having a droplet diameter of 100 μm or less and the step (B) of introducing the emulsion solution into a coalescence tank to coalesce the dispersed droplets. And a step (B) are repeated to carry out the reaction. 3. The method for producing a polycarbonate according to claim 1, wherein the residence time of the mixed solution in step (A) and step (B) is 30 minutes or less. 4. A method for producing a polycarbonate by reacting a polycarbonate oligomer with a dihydric phenol, wherein a mixed solution of a solution of the polycarbonate oligomer in an organic solvent and an alkaline aqueous solution of the dihydric phenol is introduced into a line mixer for dispersion. An emulsion solution having a droplet diameter of 100 μm or less is introduced, and at least a part of the emulsion solution from the line mixer is introduced into a coalescence tank to coalesce dispersed droplets of the emulsion solution,
A method for producing a polycarbonate, wherein the combined emulsion solution is recycled into the line mixer to carry out a reaction. 5. A method for producing a polycarbonate by reacting a polycarbonate oligomer and a dihydric phenol, wherein a mixed solution of an organic solvent solution of the polycarbonate oligomer and an alkaline aqueous solution of the dihydric phenol is provided in two or more stages in series. It is introduced into the installed line mixer, and the dispersed droplet diameter is 1 at each line mixer outlet.
Production of a polycarbonate characterized in that an emulsion solution having a size of 00 μm or less is used, and the residence time between each line mixer is set to 1 minute or more to cause the dispersed droplets in the emulsion solution to coalesce to carry out a reaction. Method. 6. A method for producing a polycarbonate by reacting a polycarbonate oligomer and a dihydric phenol, wherein a part of a mixed solution of an organic solvent solution of the polycarbonate oligomer and an alkaline aqueous solution of the dihydric phenol is placed in a reactor. It is introduced into a mixer provided in the reactor to form an emulsion solution having a dispersed droplet diameter of 100 μm or less, and the emulsion solution from the mixer is circulated in the reactor to combine the dispersed droplets of the emulsion solution. A method for producing a polycarbonate, characterized in that after the reaction, the emulsion solution containing the combined emulsion solution is recycled into the mixer to carry out the reaction. 7. The method for producing a polycarbonate according to claim 1, wherein the emulsion is a water / oil type emulsion.