JPH1067850A - Production of polycarbonate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a polycarbonate which does not undergo discoloration such as yellowing and has excellent hue, heat resistance, water resistance and boiling-water resistance by specifying the chlorine content, sodium ion content and iron ion content of a starting material comprising an aromatic organic dihydroxy compound and a carbonic diester. SOLUTION: In producing a polycarbonate by melt-polycondensing an aromatic organic dihydroxy compound with a carbonic diester, the catalyst used is an alkali metal compound or an alkaline earth metal compound in an amount of 1×10<-8> to 1×10<-4> mol of the dihydroxy compound, the content of hydrolyzable chlorine contained in the dihydroxy compound and the diester is 0.05ppm or below, the content of sodium ions contained in these monomers is 0.1ppm or below, and the content of iron ions contained in the monomers is 0.1ppm or below.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a polycarbonate, and more particularly, to a method for producing a polycarbonate having an improved color tone.

[0002]

BACKGROUND OF THE INVENTION Polycarbonate is widely used because it has excellent mechanical properties such as impact resistance, and also has excellent heat resistance and transparency. As a method for producing such a polycarbonate, an aromatic organic dihydroxy compound such as bisphenol is directly reacted with phosgene (interfacial method), or an aromatic organic dihydroxy compound such as bisphenol and a carbonate such as diphenyl carbonate are used. A method of performing a transesterification reaction (polycondensation reaction) with a diester in a molten state is known.

When a polycarbonate is produced by a transesterification reaction between an aromatic organic dihydric compound and a carbonic acid diester, the aromatic organic dihydric compound and the carbonic acid diester are converted into a metal organic acid salt or an inorganic acid salt. Since the transesterification reaction is carried out in a molten state while heating under reduced pressure at a temperature of usually 250 to 330 ° C. using a catalyst such as an oxide, a hydroxide, a hydride or an alcoholate, it is compared with the above-mentioned interface method. Thus, polycarbonate can be produced at low cost. However, since the aromatic organic dihydroxy group compound and the carbonic acid diester are reacted in a molten state, the resulting polycarbonate is exposed to a high temperature for a long time, and has a serious problem of yellowing.

[0004] Therefore, the polycarbonate obtained by the above method cannot be used in fields requiring good transparency and color tone such as plastic glass or lenses.

The inventors of the present invention have made intensive studies to solve the above-mentioned problems, and found that an aromatic organic dihydroxy compound having a low content of a specific impurity and a carbonic acid diester should be polycondensed. And completed the present invention.

[0006]

SUMMARY OF THE INVENTION The object of the present invention is to solve the problems associated with the prior art as described above, and to provide a method for producing a polycarbonate capable of obtaining a polycarbonate having an improved color tone. It is an object.

[0007]

SUMMARY OF THE INVENTION The process for producing a polycarbonate according to the present invention comprises the steps of: (b) using an alkali metal compound or an alkaline earth compound as a catalyst when producing a polycarbonate by melt polycondensing an aromatic organic dihydroxy compound and a carbonic acid diester; The metal compound is used in an amount of 1 × 10 ⁻⁸ to 1 × 10 ⁻⁴ mol per 1 mol of the aromatic organic dihydroxy compound, and the total hydrolyzable chlorine content contained in the monomer is And an aromatic organic dihydroxy group compound and a carbonic acid diester having a sodium ion content and an iron ion content in the following ranges, respectively.

[0008] Hydrolyzable chlorine content: 0.5 ppm or less Sodium ion content: 0.1 ppm or less Iron ion content: 0.1 ppm or less

In the present invention, when producing polycarbonate, the total hydrolyzable chlorine content, sodium ion content and iron ion content contained in the aromatic organic dihydroxy group compound and the carbonic acid diester used as raw materials Is less than or equal to the specific value, it is possible to obtain a polycarbonate excellent in color tone, heat resistance, water resistance and boiling water resistance without coloring yellow or the like.

[0010]

DETAILED DESCRIPTION OF THE INVENTION Hereinafter, a method for producing a polycarbonate according to the present invention will be specifically described. In the present invention, when producing a polycarbonate, an aromatic organic dihydroxy group compound and a carbonic acid diester are used. The aromatic organic dihydroxy compound used in the present invention is represented by the following formula [I]

[0011]

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R ₁ and R ₂ are a hydrogen atom or a monovalent hydrocarbon group, and R ₃ is a divalent hydrocarbon group. The aromatic nucleus may have a monovalent hydrocarbon group. ).

Specific examples of such an aromatic organic dihydroxy group compound include bis (4-hydroxyphenyl) methane, 1,1-bis (4-hydroxyphenyl) ethane, 2,2-
Bis (4-hydroxyphenyl) propane, 2,2-bis (4-
(Hydroxyphenyl) butane, 2,2-bis (4-hydroxyphenyl) octane, bis (4-hydroxyphenyl) phenylmethane, 2,2-bis (4-hydroxy-1-methylphenyl) propane, 1,1-bis Bis (hydroxyaryl) such as (4-hydroxy-t-butylphenyl) propane and 2,2-bis (4-hydroxy-3-bromophenyl) propane
Alkanes, bis (hydroxyaryl) cycloalkanes such as 1,1-bis (4-hydroxyphenyl) cyclopentane, 1,1-bis (4-hydroxyphenyl) cyclohexane, 4,4′-dihydroxydiphenyl ether, Four'-
Dihydroxy aryl ethers such as dihydroxy-3,3'-dimethylphenyl ether, 4,4'-dihydroxydiphenyl sulfide, dihydroxy diaryl sulfides such as 4,4'-dihydroxy-3,3'-dimethyl diphenyl sulfide, 4, Dihydroxydiarylsulfoxides such as 4'-dihydroxydiphenylsulfoxide, 4,4'-dihydroxy-3,3'-dimethyldiphenylsulfoxide, 4,4'-dihydroxydiphenylsulfone, 4,4'-dihydroxy-3,3'- Dihydroxydiaryl sulfones such as dimethyldiphenyl sulfone are used. Of these, 2,2-bis (4-hydroxyphenyl) propane is particularly preferred.

Examples of the carbonic acid diester include diphenyl carbonate, ditolyl carbonate, bis (chlorophenyl) carbonate, m-cresyl carbonate, dinaphthyl carbonate, bis (diphenyl) carbonate, diethyl carbonate, dimethyl carbonate, dibutyl carbonate and dibutyl carbonate. Carbonate, dicyclohexyl carbonate and the like are used. Of these, diphenyl carbonate is particularly preferred.

These carbonic acid diesters may contain a dicarboxylic acid or a dicarboxylic acid ester. Examples of such a dicarboxylic acid or dicarboxylic acid ester include terephthalic acid, isophthalic acid, diphenyl terephthalate, and diphenyl isophthalate.

When the above-mentioned dicarboxylic acid or dicarboxylic acid ester is used in combination with carbonic acid diester,
Polyester polycarbonate is obtained, and the method for producing a polycarbonate of the present invention includes the method for producing a polyester polycarbonate.

In producing the polycarbonate in the present invention, the above-mentioned carbonic acid diester is used in an amount of 1.01 to 1.30 mol, preferably 1.02 to 1.20 mol per mol of the aromatic organic dihydroxy compound. Desirably, they are used in molar amounts.

In the present invention, the total hydrolyzable chlorine content contained in the above-mentioned aromatic organic dihydroxy compound and carbonic acid diester is 0.5 ppm or less.
As used herein, the term "hydrolyzable chlorine content" refers to the content of chlorine existing as an acid such as hydrochloric acid or a salt such as sodium chloride or potassium chloride, or an organic hydrolyzable chlorine such as phenylchloroformate. Means the quantity,
It can be measured by extracting the raw material with water and performing analysis such as ion chromatography.

If the total content of hydrolyzable chlorine contained in the above-mentioned aromatic organic dihydroxy group compound and carbonic acid diester exceeds 0.5 ppm, the hue of the polycarbonate is undesirably deteriorated.

Conventionally, aromatic organic dihydroxy compounds and carbonic acid diesters, particularly carbonic acid diesters obtained by the phosgene method, have been used in the reaction by distillation or recrystallization.
Simply by distillation, the content of hydrolyzable chlorine such as phenylchloroformate contained in the aromatic organic dihydroxy group compound and the carbonic acid diester, particularly the carbonic acid diester obtained by the phosgene method, should be less than the above value. Is generally difficult.

Such a hydrolyzable carbonic acid diester having a low chlorine content has a pH of 6.0 to 9.0, preferably 7.0 to 8.5, and more preferably 7.0 to 8.0.
0 and the temperature is 78-105 ° C, preferably 80-10 ° C.
It can be easily obtained by washing with hot water at 0 ° C, more preferably at 80 to 90 ° C.

Examples of the weakly basic solution used for washing the carbonic acid diester as described above include sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium carbonate, potassium carbonate, ammonium hydroxide, sodium hydrogencarbonate, and the like. Aqueous solutions such as potassium hydrogen carbonate and tetramethylammonium hydroxide are used. Among them, aqueous solutions such as sodium hydrogen carbonate, sodium carbonate, potassium hydrogen carbonate, potassium carbonate, sodium hydrogen carbonate, and potassium hydrogen carbonate are particularly preferable.

It is preferable that the carbonic diester is washed with the above-mentioned warm water and then further distilled. When a carbonic acid diester that does not depend on the phosgene method, for example, a carbonic acid diester obtained from dialkyl carbonate, is used, the effect of washing with warm water can be reduced to 0.5 ppm or less of hydrolyzable chlorine by distillation alone in some cases.

In the present invention, the total hydrolyzable chlorine content contained in the aromatic organic dihydroxy group compound and the carbonic acid diester is not more than 0.5 ppm as described above. The total sodium ion content in the group III organic dihydric compound and the carbonic acid diester is 0.1 ppm or less, and the iron ion content is 0.1 pp.
m. Thus, in addition to reducing the total hydrolyzable chlorine content in the aromatic organic dihydroxy group compound and the carbonic acid diester to 0.5 ppm or less, the sodium ion content to 0.1 ppm or less, By setting the ion content to 0.1 ppm, a polycarbonate without further coloring can be obtained.

The contents of sodium ions and iron ions contained in the aromatic organic dihydroxy compound and the carbonic acid diester are determined by atomic absorption analysis and inductively coupled plasma emission analysis.

In order to reduce the sodium ion content and iron ion content contained in the aromatic organic dihydroxy group compound and carbonic acid diester as described above to the above-mentioned values, purification such as distillation and recrystallization is performed. Adopt it.

In the present invention, when the polycarbonate is produced by melt polycondensation of the above-mentioned aromatic organic dihydroxy compound and a carbonic acid diester, a conventionally known catalyst or newly developed by the present inventors has been proposed. A catalyst can be used. For example, catalysts described in JP-B-36-694 or JP-B-36-13942, specifically, alkali metals such as lithium, sodium, potassium, magnesium, calcium, alkaline earth metals such as barium, Zinc, cadmium, tin, antimony,
Acetates, carbonates, borates, oxides, hydroxides, hydrides or alcoholates of metals such as lead, manganese, cobalt, nickel and the like are used, and a nitrogen-containing basic compound and boric acid or borate ester are used. , Phosphorus compounds and the like can also be used. These catalysts are used in an amount of 1 × 10 ^-6 to 1 × 10 ^-1 mol, preferably 1 × 10 ^-1 mol, per mol of the aromatic organic dihydroxy compound used as a raw material.
It is preferably used in an amount of ^-5 to 1 x 10 ^-2 mol.

Hereinafter, particularly preferred catalyst systems will be described in detail. In the present invention, when producing a polycarbonate by melt polycondensation of an aromatic organic dihydroxy group compound and a carbonic acid diester, (a) a nitrogen-containing basic compound (b) an alkali metal compound or an alkaline earth metal compound ( c) It is preferable to use a catalyst such as boric acid or borate ester.

(A) Specific examples of the nitrogen-containing basic compound include tetramethylammonium hydroxide (Me ₄ N
OH), tetraethylammonium hydroxide (Et ₄ N
OH), tetrabutylammonium hydroxide (Bu ₄ N
OH),

[0030]

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Tetraalkyl or aryl, araryl ammonium hydroxides, etc., trimethylamine, triethylamine, dimethylbenzylamine,
Tertiary amines such as triphenylamine; secondary amines represented by R ₂ NH (where R is an alkyl group such as methyl and ethyl; and aryl groups such as phenyl and toluyl); RNH ₂ (wherein R Are the same as above), or ammonia, tetramethylammonium borohydride (Me ₄ NBH ₄ ), tetrabutylammonium borohydride (Bu ₄ NBH ₄ ), tetrabutylammonium tetraphenylborate (Bu ₄ NBP
h _4), and basic salts such as tetramethylammonium tetraphenylborate (Me ₄ NBPh ₄₎ is used.

Of these, tetraalkylammonium hydroxides are particularly preferred. (b) As the alkali metal compound, specifically, sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium hydrogen carbonate, potassium hydrogen carbonate, lithium hydrogen carbonate,
Sodium carbonate, potassium carbonate, lithium carbonate, sodium acetate, potassium acetate, lithium acetate, sodium stearate, potassium stearate, lithium stearate, sodium borohydride, lithium borohydride, sodium borohydride, lithium bisphenol A, Salts such as sodium, potassium, sodium benzoate, potassium benzoate, lithium benzoate, disodium hydrogen phosphate, dipotassium hydrogen phosphate, and dilithium hydrogen phosphate are used.

As the alkaline earth metal compound (b), specifically, calcium hydroxide, barium hydroxide,
Magnesium hydroxide, strontium hydroxide, calcium bicarbonate, barium bicarbonate, magnesium bicarbonate, strontium bicarbonate, calcium carbonate, barium carbonate, magnesium carbonate, strontium carbonate, calcium acetate, barium acetate, magnesium acetate, strontium acetate, calcium stearate , Barium stearate, magnesium stearate, strontium stearate and the like are used.

(C) As boric acid or borate ester, boric acid or a compound of the general formula B (OR) _n (OH) _3-n (where R is an alkyl such as methyl and ethyl, an aryl such as phenyl and the like) And n is 1, 2, or 3).

Specific examples of such borate esters include trimethyl borate, triethyl borate, tributyl borate, trihexyl borate, triheptyl borate, triphenyl borate, tritolyl borate, and trinaphthyl borate. Is used.

When the above-mentioned (a) nitrogen-containing basic compound is used, 1 × 10 ^-6 to 1 × 10 ^-1 mol, preferably 1 × 10 ^-1 mol, per 1 mol of the aromatic organic dihydroxy compound is used. 1
0 ^-5 in an amount of to 1 × 10 ^-2 mol, (b) 1 × If alkali metal compound or alkaline earth metal compound is used
10 ^-8 to 1 × 10 ^-4 mol, preferably 1 × 10 ^-7 to 1 × 1
The amount of ^0-4 mol is particularly preferably 1 × 10 ^-7 to 1 × 10 ^-5.
Used in a molar amount, and (c) if boric acid or boric acid ester is used ^{1 × 10 -8 ~1 × 10 -} 1 mol preferably in an amount of 1 × 10 ^-7 ~1 × 10 ^-2 mol Particularly preferably, it is used in an amount of 1 × 10 ^-6 to 1 × 10 ^-4 mol.

(A) The amount of the nitrogen-containing basic compound is from 1 × 10 ^-6 to 1 × 10 per 1 mol of the aromatic organic dihydroxy compound.
^{An amount of -1} mol is preferable in that the transesterification reaction and the polymerization reaction proceed at a sufficient rate, and a polycarbonate excellent in hue, heat resistance, water resistance and the like can be obtained.

(B) the amount of the alkali metal compound or the alkaline earth metal compound is one of the aromatic organic dihydroxy compound 1
When the amount is 1 × 10 ⁻⁸ to 1 × 10 ⁻⁴ mol, the polymerization activity can be increased, and a polycarbonate excellent in hue, heat resistance and water resistance can be obtained.

(C) The amount of boric acid or boric acid ester is 1 × 10 5 per mole of aromatic organic dihydroxy compound.
^The molar ratio of ^-8 to 1 × 10 ^-1 mol is preferred in that a decrease in molecular weight after thermal aging hardly occurs and a polycarbonate excellent in hue, heat resistance and water resistance can be obtained.

Thus, (a) a nitrogen-containing basic compound and (b) an alkali metal compound or an alkaline earth metal compound,
(c) boric acid or borate esters (a) and (b),
(a) and (c), (b) and (c) or (a), (b) and (c)
The catalyst consisting of has a high polymerization activity and can produce a high molecular weight polycarbonate, and the obtained polycarbonate is excellent in heat resistance and water resistance, furthermore, the color tone is improved, and the transparency is excellent. .

In the present invention, the polycondensation reaction between the aromatic organic dihydroxy compound and the carbonic acid diester is carried out under the same conditions as the conventionally known polycondensation reaction between the aromatic organic dihydric compound and the carbonic acid diester. Specifically, the first-stage reaction is carried out at a temperature of 80 to 250 ° C, preferably 100 to 230 ° C, more preferably 120 to 190 ° C for 0 to 5 hours, preferably 0 to 4 hours. Preferably, the two are reacted at normal pressure for 0.25 to 3 hours. Next, the reaction temperature is increased while reducing the pressure of the reaction system, and the reaction between the aromatic organic dihydroxy compound and the carbonic acid diester is carried out. A polycondensation reaction between the hydroxyl compound and the carbonic acid diester is performed.

The reaction between the aromatic organic dihydroxy group compound and the carbonic acid diester as described above may be carried out continuously or batchwise. The reaction apparatus used for performing the above reaction may be a tank type, a tube type, or a tower type.

[0043]

According to the present invention, when producing a polycarbonate, the content of hydrolyzable chlorine (total chlorine content) contained in the aromatic organic dihydroxy compound and the carbonic acid diester used as the raw materials and the content of sodium ion and Since the iron ion content is set to a specific value or less, a polycarbonate excellent in color tone, heat resistance, water resistance, and boiling water resistance can be obtained without coloring yellow or the like.

[0044]

EXAMPLES The present invention will be described with reference to examples, but the present invention is not limited to these examples. The physical properties of the polycarbonate obtained in the following examples were measured as described below.

Intrinsic viscosity (IV): in methylene chloride (0.5 d
1 / g) at 20 ° C. using an Ubbelohde viscometer. Hue (b value): The Lab value of a 2 mm-thick press sheet was measured using the Nippon Denshoku Industries Co., Ltd. Colorand Color Defference Meter ND-1.
Measured by the transmission method using 001 DP and used as a measure of yellowness b
Values were used.

Heat aging test: 12 at 120 ° C. and 400 mmHg
4.5 g of the dried pellets was weighed in a Teflon Petri dish (40 mmφ), and a 250 ° C. gear oven (GHPS-212) was used.
Tabai Manufacturing Co., Ltd., air exchange rate 71.6 times / hour)
After holding for a time, it was gradually cooled to room temperature. This sample was formed into a 2 mm thick press sheet, and the hue (b
Values) and IV were measured.

Boiling water test: A dumbbell having a width of 5 mm and a length of 5 cm is punched out of a 0.5 mm thick press sheet, immersed in boiling water, taken out after one day, three days, and seven days. After taking out,
Within 1 hour, distance between chucks is 3 with Instron 1132
A tensile test was performed at 0 mm, a tensile speed of 50 mm / min, and a measurement range of 50 kg, and the elongation (%) was measured.

Press sheet preparation conditions: 120 ° C., 400
The pellets dried at 12 mmHg for 12 hours were preheated at 280 ° C. for 10 minutes, pressed at 280 ° C. for 5 minutes at 100 kg / cm ³ , and cold pressed at room temperature for 5 minutes.

Hydrolyzable chlorine content: 10 g of 5 g of raw material
Eluent (2.8 mM NaHCO ₃ /2.25 mM)
After adding 10 ml of Na ₂ CO ₃ , water was added and the mixture was stirred and extracted, and the chlorine content in the extract was measured by ion chromatography (Ion Chromatograph 2000i, manufactured by DIONEX).

Sodium content: Measured by an atomic absorption method (manufactured by Hitachi, 180-80) using a 20 g sample. Iron content: Inductively coupled plasma emission spectrometry (manufactured by Nippon Jarrell Ash Co., Ltd., NJA ICPA 57) using a 20 g sample.
Measured in 5).

[0051]

Comparative Example a Hydrolyzable chlorine content is 5.9 ppm
Diphenyl carbonate (manufactured by Bayer) at 80 ° C.
After washing with warm water having a pH of 7.0, distillation under reduced pressure
With a chlorine content of 0.3 ppm that can be hydrolyzed
A phenyl carbonate was obtained. Glass reactor in reaction vessel
The diphenyl car
Bonate 51.36 g (0.24 mol) and hydrolyzable salt
Bisphenol A with 0.2 ppm elemental content (GE) 45.6
g (0.2 mol) and boric acid H_ThreeBO_Three(Wako reagent special grade) 3.
1 mg (2.5 x 10^-Fourmol / BPA 1mol) and N_TwoUnder the atmosphere, 1
The mixture was stirred at 80 ° C. and 760 mmHg for 30 minutes. Then Tet
Lamethylammonium hydroxide Me_FourNOH
15% aqueous solution (Toyo Gosei Co., Ltd.) 30.4mg (Me_FourNOH 2.5
× 10^-Fourmol / BPA 1mol), sodium hydrogen carbonate NaHCO
_Three(0.42 mg (0.25 × 10 ^-Fourmol / BPA 1mol)
At 180 ° C. and N_TwoStir for 30 minutes under atmosphere
Then, a transesterification reaction was performed.

Thereafter, the temperature was raised to 210 ° C. and gradually increased to 200 ° C.
The pressure was reduced to mmHg, and the temperature was further increased to 240 ° C for 1 hour.
Reduce the pressure gradually to 150 mmHg for 20 minutes at 00 mmHg
Minutes, further reduced to 100 mmHg for 20 minutes, reduced to 15 mmHg for 0.5 hours, and then heated to 270 ° C.
Finally, the pressure was reduced to 0.5 mmHg and the reaction was carried out for 2.5 hours.
A polycarbonate having an IV of 0.55 dl / g was obtained. The b value of this polycarbonate was 1.3. Table 1 shows the results.

[0053]

Comparative Examples bc In Comparative Example a, the DPCs shown in Table 1 differing in the hydrolyzable chlorine content, sodium ion content and iron ion content by changing the degree of purification (recovery rate in vacuum distillation) of diphenyl carbonate. Then, polymerization was carried out by the method described in Comparative Example a to obtain a polycarbonate. Table 1 shows the results.

[0054]

Comparative Example d Polymerization was carried out in the same manner as in Comparative Example a, except that diphenyl carbonate obtained by distilling Eni manufactured from dimethyl carbonate was used in place of diphenyl carbonate manufactured by Bayer in Comparative Example a. Done. Table 1 shows the results.

[0055]

Comparative Example 1 Polymerization was carried out in the same manner as in Comparative Example a except that unpurified diphenyl carbonate was used. Table 1 shows the results.

[0056]

Comparative Example 2 Polymerization was carried out in the same manner as in Comparative Example a except that undistilled diphenyl carbonate from Eni was used instead of diphenyl carbonate from Bayer. Table 1 shows the results.

[0057]

[Table 1]

[0058]

Example 1 Diphenyl carbonate (manufactured by Bayer) having a hydrolyzable chlorine content of 5.9 ppm was washed twice with hot water at pH 7.0 at 80 ° C., and then distilled under reduced pressure to recover 90%. A diphenyl carbonate having a chlorine content of 0.1 ppm or less, which can be hydrolyzed at a high rate, was obtained. Using a glass reactor as the reaction vessel and using a stirring bar of Ni, 143.8 g (0.672 mol) of this diphenyl carbonate and bisphenol A having a hydrolyzable chlorine content of 0.1 ppm or less were used.
136.8 g (0.6 g by Nippon GE Plastics)
00 mol) and boric acid H ₃ BO ₃ , 3 mg aqueous solution 3.0 mg (H ₃ BO _3)
3 0.025 × 10 ^-4 mol / BPA 1 mol) under N ₂ atmosphere for 18
The temperature was raised to 0 ° C. Thereafter, 91.2 mg (Me ₄ NOH 2.5 × 10 ⁻⁴ mol / BPA 1 mol) of a 15% aqueous solution of tetramethylammonium hydroxide (Me ₄ NOH) (manufactured by Toyo Gosei Co., Ltd.) and a 0.1% aqueous solution of sodium hydroxide (NaOH) 24.0 mg (0.01
0 × 10 ^-4 mol / BPA 1 mol), and further added at 180 ° C.
_The mixture was stirred under _two atmospheres for 30 minutes to perform a transesterification reaction.

Thereafter, the temperature was raised to 210 ° C. and gradually increased to 200 ° C.
The pressure was reduced to mmHg, the temperature was further increased to 240 ° C. for 1 hour, and the temperature was increased to 200 mmHg for 20 minutes.
After reducing the pressure to 50 mmHg, the pressure was reduced to 15 mmHg for 20 minutes.
After reacting for 5 hours, the temperature was raised to 270 ° C.
The reaction was reduced to 5 mmHg for 2.5 hours. IV is 0.5
5 dl / g of polycarbonate was obtained almost quantitatively. The b value of this polycarbonate was 0.7. Table 2 shows the results.

[0060]

Examples 2 to 3 In Example 1, the DPC described in Table 2 having different hydrolyzable chlorine content, sodium ion content and iron ion content was obtained by changing the degree of purification (recovery rate in vacuum distillation) of diphenyl carbonate. Then, polymerization was carried out by the method described in Example 1 to obtain a polycarbonate. Table 2 shows the results.

[0061]

Example 4 Polymerization was carried out in the same manner as in Example 1, except that diphenyl carbonate produced from dimethyl carbonate as a raw material was distilled instead of diphenyl carbonate in Example 1. Table 2 shows the results.

[0062]

Example 5 In Example 1, sodium hydroxide (Na
OH) Instead of 0.1% aqueous solution, use sodium hydrogen carbonate (NaH
50.4 mg of 0.2% aqueous solution of CO ₃ (NaHCO ₃ 0.02 × 10 ^-4 mol /
Polymerization was carried out in the same manner as in Example 1, except that 1 mol of BPA was used. Table 2 shows the results.

[0063]

Example 6 In Example 1, sodium hydroxide (Na
OH) Instead of 0.1% aqueous solution, lithium stearate (C
₁₇H₃₅COOLi) 34.8mg of 1% aqueous solution (C₁₇H₃₅COOLi 0.02
× 10 ^-Fourmol / BPA 1 mol) was used in Example 1.
Polymerization was performed as described above. Table 2 shows the results.

[0064]

[Table 2]

[0065]

Example 7 In Example 1, sodium hydroxide (Na
OH) Instead of 0.1% aqueous solution

[0066]

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Polymerization was carried out in the same manner as in Example 1 except that (× 10 ⁻⁴ mol / BPA 1 mol) was used. Table 3 shows the results.

[0068]

Example 8 In Example 1, sodium hydroxide (Na
OH) 42.6 mg of 0.1% aqueous solution of sodium dihydrogen phosphate (Na ₂ HPO ₄ ) instead of 0.1% aqueous solution (Na ₂ HPO ₄ 0.005)
× 10 ^{- 4} except for using mol / a BPA 1 mol), polymerization was carried out by the method described in Example 1. Table 3 shows the results.

[0069]

Example 9 In Example 1, sodium hydroxide (Na
OH) Instead of 0.1% aqueous solution

[0070]

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Polymerization was carried out in the same manner as in Example 1 except that was used. Table 3 shows the results.

[0072]

Comparative Example 3 Polymerization was carried out in the same manner as in Example 1 except that unpurified diphenyl carbonate was used. Table 3 shows the results.

[0073]

Comparative Example 4 Polymerization was carried out in the same manner as in Example 1 except that diphenyl carbonate of Eni was used instead of diphenyl carbonate of Example 1. Table 3 shows the results.

[0074]

[Table 3]

Claims (1)

[Claims] 1. A process for producing a polycarbonate by melt-polycondensing an aromatic organic dihydroxy compound with a carbonic acid diester, wherein (b) an alkali metal compound or an alkaline earth metal compound is used as a catalyst. It is used in an amount of 1 × 10 ⁻⁸ to 1 × 10 ⁻⁴ mol per 1 mol of the compound, and the total hydrolyzable chlorine content, sodium ion content and iron ion content contained in the above monomer Using an aromatic organic dihydric compound and a carbonic acid diester, each having the following ranges: Hydrolyzable chlorine content: 0.5 ppm or less Sodium ion content: 0 0.1 ppm or less Iron ion content: 0.1 ppm or less