JP3056028B2 - Method for producing polycarbonate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing polycarbonate. Specifically, the molecular weight is increased,
The present invention relates to a method for producing a polycarbonate having excellent quality such as hydrolysis resistance.

[0002]

2. Description of the Related Art Generally, as a method for producing polycarbonate (hereinafter sometimes referred to as PC), a method of directly reacting an aromatic dihydroxy compound such as bisphenol A with phosgene ( An interfacial polycondensation method), or a method of transesterifying an aromatic dihydroxy compound such as bisphenol A with a carbonic acid diester such as diphenyl carbonate in a molten state (melting method) is known. In the method of manufacturing PC, the above-mentioned interfacial polycondensation method requires the use of toxic phosgene, the manufacturing equipment is corroded by chlorine-containing compounds such as hydrogen chloride and sodium chloride as by-products, and is mixed into the resin. There are various problems such as difficulty in separating impurities such as sodium hydroxide which adversely affect the physical properties of the polymer.

[0003] On the other hand, the melting method has an advantage that PC can be produced at a lower cost than the interfacial polycondensation method, but usually requires a long-time reaction at a high temperature of 280 to 310 ° C. In addition, it has a major drawback in that it cannot escape from the problem of resin coloring. In addition, a basic catalyst is often used in the production process, and the resulting PC
Has poor hydrolysis resistance. In such a melting method, various improved techniques have been proposed to reduce the coloring. For example, Japanese Patent Publication No. 61-399
No. 72 and JP-A-63-223036 disclose a method using a specific catalyst. Also, JP-A-61-151236 and JP-A-62-15871.
No. 9 discloses a method of adding an antioxidant at a later stage of the reaction. Japanese Unexamined Patent Publications Nos. 61-62522 and 2-153925 disclose process improvement techniques such as using a twin-screw vented kneading extruder and a horizontal stirring polymerization tank at the latter stage of the reaction. Have been. Further, Japanese Patent Application Laid-Open No. 2-175722 discloses a method for reducing the content of hydrolyzable chlorine in a monomer to a certain level or less. As a method for improving the hydrolysis resistance of PC, neutralization with a volatile acid such as dimethylsulfuric acid has been conventionally known.
A technique of neutralizing with an acid such as toluenesulfonic acid and neutralizing excess acid with epoxy (JP-A-4-1753)
No. 68) is also known. However, the quality problem as described above has not been completely solved, and a satisfactory P
The fact is that C has not yet been obtained. Therefore, an object of the present invention is to provide a method for producing a polycarbonate having a high molecular weight in a melting method and excellent in quality such as coloring property and hydrolysis resistance.

[0004]

In view of the above-mentioned situation, the present inventors have developed a method for producing a polycarbonate capable of efficiently producing a PC having no coloring and having excellent quality such as hydrolysis resistance. As a result of intensive studies, it has been found that the above problem can be solved by sequentially adding at least one monomer of a dihydroxy compound and a carbonic acid diester as a raw material in a method for producing PC by transesterification. That is, the present invention relates to a method for producing a polycarbonate from a dihydroxy compound (A) and a diester carbonate (B) by a transesterification method, wherein at least one monomer of the dihydroxy compound (A) and the diester carbonate (B) is used. Are sequentially added, and a method for producing a polycarbonate is provided.

Hereinafter, the present invention will be described in more detail. In the present invention, there are various dihydroxy compounds used as the component (A). For example, it is selected from aromatic dihydroxy compounds, aliphatic dihydroxy compounds, bisesters of aromatic dihydroxy compounds, bisesters of aliphatic dihydroxy compounds, carbonates of aromatic dihydroxy compounds, and carbonates of aliphatic dihydroxy compounds. At least one compound. The aromatic dihydroxy compound used as one of the components (A) has the general formula (I)

[0006]

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Wherein R is a halogen atom (eg, chlorine, bromine, fluorine, iodine) or an alkyl group having 1 to 8 carbon atoms (eg, methyl, ethyl, propyl, n-butyl, Isobutyl group, amyl group, isoamyl group, hexyl group, etc.).
They may be the same or different,
m is an integer of 0 to 4. Z is a single bond, an alkylene group having 1 to 8 carbon atoms or an alkylidene group having 2 to 8 carbon atoms (for example, methylene group, ethylene group, propylene group, butylene group, pentylene group, hexylene group, ethylidene group, isopropylidene group) Riden group etc.), carbon number 5-15
Cycloalkylene group or a cycloalkylidene group having 5 to 15 carbon atoms (e.g., cyclopentylene group, cyclohexylene group, cyclopentylidene group, etc. cyclohexylidene group), or -S -, - SO -, - SO 2 -, -O
-, -CO- bond or formula (II) or (II ')

[0008]

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[0009] The bond represented by And an aromatic dihydroxy compound represented by the formula: Examples of such an aromatic dihydroxy compound include bis (4-hydroxyphenyl) methane; 1,1-bis (4-hydroxyphenyl) ethane; and 2,2-bis (4-hydroxyphenyl) propane (commonly known as 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-dimethylphenyl) propane; 2,2-bis (4-hydroxy-3-chlorophenyl) propane;
2,2-bis (4-hydroxy-3,5-dichlorophenyl) propane; 2,2-bis (4-hydroxy-3,
Bis (hydroxyaryl) alkanes such as 5-dibromophenyl) propane; 1,1-bis (4-hydroxyphenyl) cyclopentane; 1,1-bis (4-hydroxyphenyl) cyclohexane; 1,1-bis (4 −
Bis (hydroxyaryl) cycloalkanes such as (hydroxyphenyl) -3,5,5-trimethylcyclohexane; 4,4-dihydroxydiphenyl ether;
Dihydroxyaryl ethers such as 4,4′-dihydroxy-3,3′-dimethylphenyl ether;
4'-dihydroxydiphenyl sulfide; 4,4'-
Dihydroxydiaryl sulfides such as dihydroxy-3,3'-dimethyldiphenyl sulfide;
4'-dihydroxydiphenylsulfoxide; 4,4 '
Dihydroxyarylsulfoxides such as -dihydroxy-3,3'-dimethyldiphenylsulfoxide;
4,4'-dihydroxydiphenyl sulfone; 4,4 '
Dihydroxydiarylsulfones such as -dihydroxy-3,3'-dimethyldiphenylsulfone, dihydroxybenzene, halogen- and alkyl-substituted dihydroxybenzenes, for example, 1,4-dihydroxy-2,5-dichlorobenzene; 1,4-dihydroxy-3- Methylbenzene and the like can be mentioned.

The aliphatic dihydroxy compound as one of the components (A) includes various 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-
Ethoxylated or propoxylated products of (4-hydroxycyclohexyl) -propane and dihydric alcohols or phenols, such as bis-oxyethyl-bisphenol A; bis-oxyethyl-tetrachlorobisphenol A or bis-oxyethyl-tetrachlorohydroquinone. Can be

Examples of bisesters of aromatic dihydroxy compounds, bisesters of aliphatic dihydroxy compounds, carbonates of aromatic dihydroxy compounds, and carbonates of aliphatic dihydroxy compounds used as component (A) include: The bisesters of the above compounds have the general formula (III)

[0012]

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[Wherein, R ¹ represents a residue obtained by removing two hydroxyl groups from the above-mentioned aliphatic dihydroxy compound, and R ² represents an alkyl group having 1 to 6 carbon atoms or a carbon atom having 4 to 4 carbon atoms.
A cycloalkyl group having 7 is shown. Represented by the general formula (IV)

[0014]

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[In the formula, Ar ¹ represents a residue obtained by removing two hydroxyl groups from the above aromatic dihydroxy compound, and R ² is the same as described above. A compound represented by the general formula (V):

[0016]

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[In the formula, Ar ² represents an aryl group, and R ¹ is the same as described above. Or a compound represented by the general formula
(VI)

[0018]

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Wherein Ar ¹ and Ar ² are the same as above. ] The compound represented by this is mentioned. Further, as the carbonates of the above compound, a compound of the general formula (VII)

[0020]

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Wherein R ¹ and R ² are as defined above. Represented by the general formula (VIII)

[0022]

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Wherein R ² and Ar ¹ are the same as above. Represented by the general formula (IX)

[0024]

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Wherein R ¹ and Ar ² are the same as above. Or a compound represented by the general formula (X)

[0026]

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Wherein Ar ¹ and Ar ² are the same as above. ] The compound represented by this is mentioned. In the present invention, the above compounds are appropriately selected and used as the dihydroxy compound of the component (A), and among these, bisphenol A, which is an aromatic dihydroxy compound, is preferably used. When bisphenol A is used, an adduct of bisphenol A and phenol or a mixture of the adduct and phenol can also be used. By using such an adduct, bisphenol A with high purity can be obtained, which is effective.

On the other hand, in the present invention, there are various carbonate diesters used as the component (B). For example, it is at least one compound selected from diaryl carbonate compounds, dialkyl carbonate compounds and alkylaryl carbonate compounds. The diaryl carbonate compound used as one of the components (B) has the general formula (XI)

[0029]

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Wherein Ar ² is the same as above. Or a compound represented by the general formula (X)

[0031]

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Wherein Ar ¹ and Ar ² are the same as above. ] It is a compound represented by these. Further, the dialkyl carbonate compound has the general formula (XII)

[0033]

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Wherein R ² is the same as above. Represented by the general formula (VIII)

[0035]

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Wherein R ² and Ar ¹ are the same as above. ] It is a compound represented by these. And the alkyl aryl carbonate compound has the general formula (XIII)

[0037]

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Wherein R ² and Ar ² are the same as above. Represented by the general formula (XIV)

[0039]

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Wherein R ² , Ar ¹ and Ar ² are the same as above. ] It is a compound represented by these. Here, examples of the diaryl carbonate compound include diphenyl carbonate, ditolyl carbonate, bis (chlorophenyl) carbonate, m-cresyl carbonate, dinaphthyl carbonate, bis (diphenyl) carbonate, and bisphenol A bisphenyl carbonate.
Examples of the dialkyl carbonate compound include diethyl carbonate, dimethyl carbonate, dibutyl carbonate, dicyclohexyl carbonate, and bisphenol A bismethyl carbonate. Examples of the alkylaryl carbonate compound include methyl phenyl carbonate, ethyl phenyl carbonate, butyl phenyl carbonate, cyclohexyl phenyl carbonate, and bisphenol A methyl phenyl carbonate. Among these, diphenyl carbonate is particularly preferred. In the present invention,
As the carbonic acid diester of the component (B), the above compounds are appropriately selected and used, and among them, diphenyl carbonate is preferably used.

The production method of the present invention comprises the above component (A),
A polycarbonate is produced by a transesterification reaction using the component (B) and other components. In the transesterification reaction, at least one of a dihydroxy compound as the component (A) and a carbonate diester as the component (B) is used. Are sequentially added. That is, for example, when one of the components (A) and (B) is successively added, and the component to be sequentially added is the diester carbonate (B), the required amount of the dihydroxy compound of the component (A) is reduced. On the other hand, the required amount of the carbonic acid diester of the component (B) is divided into a plurality of times and added sequentially. When the component to be sequentially added is the component (A), the procedure may be reversed.

Hereinafter, the procedure and conditions of the production method of the present invention will be specifically described. First, the dihydroxy compound of the component (A) and the carbonic acid diester of the component (B) are subjected to transesterification at a ratio such that the total amount of the carbonic acid diester is 1 to 1.5 times the molar amount of the dihydroxy compound. The amount of the carbonic acid diester is preferably 1.02 to 1.20 times the molar amount of the dihydroxy compound depending on the situation.

In carrying out the transesterification reaction in the present invention, the reaction temperature is not particularly limited, but is usually from 100 ° C.
330 ° C., preferably 180 ° C. to 300 ° C.
° C, more preferably 18 ° C as the reaction progresses.
A good method is to increase the temperature from 0 ° C to 300 ° C. When the transesterification reaction is less than 100 ° C., the progress of the reaction is slow,
If the temperature exceeds 330 ° C., thermal degradation of the polymer occurs, which is not preferable. The reaction pressure can be set according to the vapor pressure of the monomer to be used and the reaction temperature so that the reaction can be carried out efficiently. Further, the reaction time may be set to a target molecular weight, and is generally about 0.2 to 10 hours in total.

In the case where at least one of the component (A) and the component (B) of the starting monomer is added successively as in the present invention, the transesterification reaction is particularly preferably 5 to 60%.
It is carried out, and one of the components (A) and (B) of the raw material monomer is added in an amount of 1 to 8 of the charged amount to be added.
0% at the beginning of the reaction, then at the middle of the reaction in which the transesterification reaction is preferably carried out at 40-95%, more preferably at 60-95%, and preferably at 90-95%.
It is desirable to carry out the reaction separately in the latter half of the reaction in which the reaction is performed at 100%, more preferably at 95 to 100%. First, in the initial stage of the above reaction, one of the component (A) and the component (B) of the raw material monomer is added in an amount of 1 to 1 to be added.
In a system charged at a rate of 80%, preferably 5-60%, the reaction temperature is 150-260 ° C, preferably 180 ° C.
~ 240 ° C temperature range, reaction pressure 760 ~ 50mmH
g, preferably 760 to 200 mmHg. In the initial stage of the reaction,
When the reaction temperature is lower than 150 ° C., the transesterification reaction is not sufficient, and when the reaction temperature is higher than 260 ° C., the starting monomer may be deteriorated, which is not preferable. When the reaction pressure is 5
If it is less than 0 mmHg, distillation of the raw material monomer cannot be ignored, which is not preferable.

Next, in the middle stage of the reaction, the reaction temperature is 200-200.
300 ° C., preferably 210-260 ° C., reaction pressure 500-5 mmHg, preferably 400-10 mHg
Preferably, the reaction is carried out under conditions in the range of mHg. Furthermore, in the latter stage of the reaction, the reaction temperature is in the range of 200 to 300 ° C, preferably 210 to 260 ° C, and the reaction pressure is 500 to 500 ° C.
After carrying out the reaction under the condition of a pressure range of 5 mmHg, preferably 400 to 10 mmHg, the reaction temperature and the degree of vacuum are raised to a reaction temperature of 240 to 320 ° C, preferably 26 to 320 ° C.
Under the temperature range of 0 to 300 ° C. and the reaction pressure of 5 mmHg or less, preferably 1 mmHg or less, the remaining amount of the components added sequentially is added and reacted. In the present invention, in consideration of the influence on the quality such as the amount of residual monomer after the completion of the reaction, it is preferable to add the compound in the later stage of the reaction under the condition of decreasing the addition amount, for example, at a temperature of 250 ° C. or more and a pressure of 1 mmHg or less. preferable. When the present invention is carried out in a plurality of stages, particularly in a reaction of four or more stages, any of the initial stage, the middle stage and the late stage of the reaction can be further divided into a plurality of stages. It is preferable to carry out in two or more stages.

The above reaction is carried out in the absence of an inert solvent. If necessary, the reaction may be carried out in the presence of an inert solvent of 1 to 150% by weight of the obtained PC. Here, examples of the inert solvent include aromatic compounds such as diphenyl ether, halogenated diphenyl ether, diphenyl sulfone, benzophenone, polyphenyl ether, dichlorobenzene, and methylnaphthalene; gases such as carbon dioxide, nitrous oxide, and nitrogen; Various types such as chlorofluorohydrocarbons, alkanes such as ethane and propane, cycloalkanes such as cyclohexane, tricyclo (5,2,10) -decane, cyclooctane and cyclodecane, alkenes such as ethene and propene, and sulfur hexafluoride. No. When producing a polycarbonate by this transesterification reaction, the component (A) and the component (B)
In addition to the components, the following terminal stoppers can be used, if necessary. Specific examples of such a terminal capping agent include on-butylphenol; mn-butylphenol; pn-butylphenol; o-isobutylphenol; m-isobutylphenol; p-isobutylphenol; Mt-butylphenol; pt-butylphenol; on-pentylphenol; mn-pentylphenol;
n-pentylphenol; on-hexylphenol; mn-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;

[0047]

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Compounds represented by the following formulas and 2,5-dicumylphenol; 3,5-dicumylphenol, and chroman derivatives such as those represented by the formula

[0049]

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And other monohydric phenols. Among such phenols, although not particularly limited in the present invention, p-tert-butylphenol; p-cumylphenol; p-phenylphenol and the like are preferable. Also, the formula

[0051]

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And the like.

In the transesterification reaction, the amount of the terminal terminator comprising the above-mentioned monohydric phenol or the like is determined as follows:
With respect to 1 mole of the dihydroxy compound as the component (A),
When the content is in the range of 0.05 mol% to 10 mol%, the hydroxyl terminal of the obtained polycarbonate is sealed, so that a polycarbonate sufficiently excellent in heat resistance and water resistance can be obtained,
In addition, the polycondensation reaction rate is increased, which is preferable. Such a terminal terminator comprising a monohydric phenol or the like may be added in advance to the reaction system in its entirety. Alternatively, a part may be added to the reaction system in advance, and the remainder may be added as the reaction proceeds. Further, in some cases, the whole amount may be added to the reaction system after the transesterification reaction between the dihydroxy compound of (A) and the carbonic acid diester of (B) partially proceeds.

In the present invention, if necessary, a simple substance of an alkali metal or alkaline earth metal, an oxide, a hydroxide, an amide compound, an alcoholate, a phenolate, or a base such as ZnO, PbO, or Sb ₂ O _3. Metal oxide, organic titanium compound, soluble manganese compound, C
a, Mg, Zn, Pb, Sn, Mn, Cd, Co acetate or nitrogen-containing basic compound and boron compound, nitrogen-containing basic compound and alkali (earth) metal compound, nitrogen-containing basic compound and alkali ( (Earth) A catalyst such as a combined catalyst of a metal compound and a boron compound can be used. Further, in the present invention, if necessary, phloroglucin; trimellitic acid; 1,1,1-tris (4-hydroxyphenyl) ethane; 1- [α-methyl-α- (4′-hydroxyphenyl) ethyl] -4- [α ', α'-bis (4 "-hydroxyphenyl) ethyl] benzene;
α ′, α ″ -tris (4-hydroxyphenyl) -1,
3,5-triisopropylbenzene; isatin bis (o
-Cresol) can also be used as a branching agent.
In the present invention, an antioxidant can be used as needed. Specific examples include tris (nonylphenyl) phosphite, trisphenyl phosphite,
-Phosphorus antioxidants such as ethylhexyl diphenyl phosphite, trimethyl phosphite, triethyl phosphite, tricresyl phosphite, and triaryl phosphite.

In the present invention, as the reaction proceeds, phenols corresponding to the carbonic acid diester used,
Alcohols or their esters and inert solvents desorb from the reactor. These desorbed substances can be separated, purified and recycled for use, and it is preferable to have equipment for removing them. And the present invention can be carried out batchwise or continuously, and any device can be used. In the case of continuous production, it is preferable to use at least two or more reactors and set the above reaction conditions. Although the material of the reactor used in the present invention contains the above-mentioned metals, the structure thereof is not particularly limited, but it is sufficient that the reactor has a normal stirring function. However, since the viscosity increases in the latter stage of the reaction, those having a high viscosity type stirring function are preferable. Further, the shape of the reactor is not limited to a tank type, and may be an extruder type reactor or the like.

The PC obtained as described above may be granulated as it is, or may be formed using an extruder or the like. The PC obtained by the present invention can be used by blending known additives such as a plasticizer, a pigment, a lubricant, a release agent, a stabilizer, and an inorganic filler. Further, the obtained PC can be blended with a polymer such as polyolefin, polystyrene, polyester, polysulfonate, polyamide, and polyphenylene oxide. Particularly, OH group, COOH group, NH ₂
It is effective when used in combination with polyphenylene ether, polyether nitrile, terminal-modified polysiloxane compound, modified polypropylene, modified polystyrene or the like having a group or the like at the terminal.

[0057]

EXAMPLES The present invention will be described more specifically with reference to the following examples. The present invention is not limited by the following examples. Examples 1-4 and Comparative Example 1 Bisphenol A (BP) was placed in an ampoule tube having an inner diameter of 12 mm.
A) and diphenyl carbonate (DPC) were added in the amounts shown in Table 1 and nitrogen replacement was performed five times (step 1). Then, the temperature was raised and reacted at 180 ° C. for 1 hour.
Add A or DPC to the amount shown in Table 1 (Step 2), 2
The temperature was raised to 10 ° C and the degree of vacuum was set to 200 mmHg.
Incubate for 60 minutes. Here, BPA or DPC is first again
The amount shown in the table was added (Step 3), the temperature was raised to 240 ° C., and the degree of decompression was gradually increased to finally 15 mmHg.
The reaction time at 240 ° C. was 1 hour and 30 minutes. Further, here, BPA or DPC was added in the amount shown in Table 1 (step 4) and reacted at 270 ° C. and 1 mmHg for 2 hours 30 minutes. After the completion of the reaction in step 3 or 4, the product was sampled and the molecular weight Mw was measured. The results are shown in Table 1.

Example 5 Using a 100 ml three-necked flask (with a stirrer), the total amount of bisphenol A charged was 11.4 g (0.05%).
Mol), the total charge of diphenyl carbonate was 11.2.
The same operation as in Example 1 was carried out except that the amount was changed to 35 g (0.0525 mol). Viscosity average molecular weight (2 in Ubbelohde type viscosity tube)
The viscosity of the methylene chloride solution at 0 ° C. was measured, and the intrinsic viscosity was determined from this. [Η] = 1.23 × 10 ⁻⁵ × Mv
⁽ Calculated from ^0.83 ) was 16,300. In addition, after the polymer plate (thickness: 3 mm) obtained here was exposed to steam at 121 ° C. for 48 hours, the appearance was transparent and the hydrolysis resistance was good. After the completion of the reaction in step 3 or 4, the product was sampled and the molecular weight Mw was measured. The results are shown in Table 1.

[0059]

[Table 1]

[0060]

[Table 2]

[0061]

As described in detail above, in the transesterification reaction between the dihydroxy compound (A) and the diester carbonate (B) as in the present invention, by adding at least one monomer sequentially, the coloring property and the resistance to A polycarbonate having excellent quality such as hydrolyzability can be efficiently produced. Therefore, the present invention can be effectively and widely used as a method for industrially advantageously producing a polycarbonate by a transesterification method.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-4-239024 (JP, A) JP-A-2-251522 (JP, A) JP-A-64-16826 (JP, A) JP-A-62- 187725 (JP, A) JP-B 33-8300 (JP, B1) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08G 64/00-64/42

Claims (2)

(57) [Claims] 1. A process for producing a polycarbonate from an aromatic dihydroxy compound (A) and an aromatic diester (B) by a transesterification method, wherein (A)
Aromatic dihydroxy compound of the component and (B) at least one monomer of the aromatic carbonic acid diester of the component, S.
Sequential addition in early, middle and late stages of the terexchange reaction
And the monomer added at the beginning of the transesterification
A method for producing a polycarbonate, wherein the amount is 5 to 60% of the charged amount to be added . 2. A method for producing a polycarbonate from an aromatic dihydroxy compound (A) and an aromatic diester carbonate (B) by a transesterification method, wherein (A)
Aromatic dihydroxy compound of the component and (B) one of the monomers of aromatic carbonic acid diester of the component, Este
The initial, middle and late stages of the exchange reaction
Amount of monomer added at the beginning of transesterification
Is 5 to 60% of the charged amount to be added .