JPH0618868B2 - Method for producing polycarbonate - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION 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.

TECHNICAL BACKGROUND OF THE INVENTION AND PROBLEMS THEREOF Polycarbonate is widely used because it has excellent mechanical properties such as impact resistance, and also excellent heat resistance and transparency. As a method for producing such a polycarbonate, a method of directly reacting an aromatic organic dihydroxyl compound such as bisphenol with phosgene (interfacial method),
Alternatively, a method is known in which an aromatic organic dihydroxyl compound such as bisphenol and a carbonic acid diester such as diphenyl carbonate are transesterified (polycondensation reaction) in a molten state.

By the way, when a polycarbonate is produced by a transesterification reaction between an aromatic organic dihydroxyl compound and a carbonic acid diester, an aromatic organic dihydroxyl compound and a carbonic acid diester are treated with a metal organic acid salt, an inorganic acid salt, or an oxide. It is cheaper than the above-mentioned interfacial method because the transesterification reaction is carried out in the molten state while heating under reduced pressure at a temperature of 250 to 330 ° C. using a catalyst such as hydroxide, hydride or alcoholate. In addition, it has the advantage that polycarbonate can be produced. However, since the aromatic organic dihydroxyl 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, which causes a big problem that it is colored yellow.

For this reason, the polycarbonate obtained by the above method could not be used in the fields such as plastic glass and lenses where good color tone is required.

The present inventors have conducted extensive studies to solve the above problems, and found that it is sufficient to polycondense an aromatic organic dihydroxyl compound having a small content of specific impurities and a carbonic acid diester. The present invention has been completed.

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

SUMMARY OF THE INVENTION The first method for producing a polycarbonate according to the present invention is a method of producing a polycarbonate by melt polycondensation of an aromatic organic dihydroxyl compound and a carbonic acid diester. It is characterized by using an aromatic organic dihydroxy compound and a carbonic acid diester having a possible chlorine content in the following range.

Hydrolyzable chlorine content: 3 ppm or less Further, in the second method for producing a polycarbonate according to the present invention, in producing a polycarbonate by melt polycondensation of an aromatic organic dihydroxyl compound and a carbonic acid diester,
The total content of hydrolyzable chlorine contained in the above-mentioned monomers, the content of sodium ion and the content of iron ion in the following ranges, respectively, use an aromatic organic dihydroxyl compound and a carbonic acid diester. It has a feature.

Hydrolyzable chlorine content: 3 ppm or less Sodium ion: 1.0 ppm or less Iron ion: 1.0 ppm or less In the present invention, it is contained in the aromatic organic dihydroxyl compound and carbonic acid diester used as raw materials when producing a polycarbonate. The content of hydrolyzable chlorine that is less than or equal to a specific value, and further the content of sodium ions and iron ions contained in the raw material as described above is less than or equal to a specific value, so that the color tone does not change to yellow or the like, A polycarbonate excellent in heat resistance, water resistance and boiling water resistance can be obtained.

DETAILED DESCRIPTION OF THE INVENTION The method for producing a polycarbonate according to the present invention will be specifically described below.

In the present invention, when a polycarbonate is produced, an aromatic organic dihydroxyl compound and a carbonic acid diester are used.

The aromatic organic dihydroxyl compound used in the present invention,
The following formula [I] (Where X is -O -, - S -, - SO- or -SO ₂ - and is, R
₁ and R ₂ are hydrogen atoms or monovalent hydrocarbon groups, and R ₃ is a divalent hydrocarbon group. The aromatic nucleus is 1
It may have a valent hydrocarbon group. ) Is a compound represented by.

Specific examples of such aromatic organic dihydroxyl compounds include bis (4-hydroxyphenyl) methane, 1,1-bis (4-hydroxyphenyl) ethane, and 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 (4-hydroxy-t-butylphenyl) propane, 2,2-bis (4-hydroxy-3-bromophenyl)
Bis (hydroxyaryl) alkanes such as propane, 1,1-bis (4-hydroxyphenyl) cyclopentane, bis (hydroxyaryl) cycloalkanes such as 1,1-bis (4-hydroxyphenyl) cyclohexane,
Dihydroxy aryl ethers such as 4,4'-dihydroxydiphenyl ether and 4,4'-dihydroxy-3,3'-dimethylphenyl ether, 4,4'-dihydroxydiphenyl sulfide, 4,4'-dihydroxy-3,3 ' -Dihydroxy diaryl sulfides such as dimethyl diphenyl sulfide, 4,4'-dihydroxy diphenyl sulfoxide, dihydroxy diaryl sulfoxides such as 4,4'-dihydroxy-3,3'-dimethyl diphenyl sulfoxide, 4,4'-dihydroxy diphenyl sulfone , 4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfone and other dihydroxydiaryl sulfones are used.

Of these, 2,2-bis (4-hydroxyphenyl) propane is particularly preferable.

Specific 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, dicyclohexyl. Carbonate or the like is used.

Of these, diphenyl carbonate is particularly preferable.

Further, these carbonic acid diesters may contain a dicarboxylic acid or a dicarboxylic acid ester. Examples of such 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, a polyester polycarbonate is obtained. The method for producing a polycarbonate of the present invention also includes a method for producing this polyester polycarbonate.

In producing a polycarbonate according to the present invention, the amount of the carbonic acid diester is 1.01 to 1.30 mol, preferably 1.02 to 1.20 mol, per 1 mol of the aromatic organic dihydroxyl compound. It is desirable to be used in.

In the present invention, the total content of hydrolyzable chlorine contained in the above aromatic organic dihydroxyl compound and carbonic acid diester is 3 ppm or less, preferably 2 ppm or less, more preferably 1 ppm or less.

The term "hydrolyzable chlorine content" as used herein means the presence 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 quantity,
It can be measured by extracting the raw material with water and conducting an analysis such as ion chromatography.

If the total content of hydrolyzable chlorine contained in the aromatic organic dihydroxy compound and the carbonic acid diester exceeds 3 ppm, the hue of the polycarbonate is deteriorated, which is not preferable.

In the present invention, the content of hydrolyzable chlorine contained in the carbonic acid diester is particularly preferably 2 ppm or less, preferably 1 ppm or less, more preferably 0.5 ppm or less.

Conventionally, aromatic organic dihydroxyl compounds and carbonic acid diesters have been used for the reaction by distilling or recrystallizing the carbonic acid diesters obtained by the phosgene method. However, simply distilling the aromatic organic dihydroxyl compound and carbonic acid diester In particular, it is generally difficult to set the content of hydrolyzable chlorine such as phenylchloroformate contained in the carbonic acid diester obtained by the phosgene method to the above value or less.

The carbonic acid diester having a small hydrolyzable chlorine content has a pH of 6.0 to 9.0, preferably a pH of 7.0.
8.5 More preferably, the pH is 7.0 to 8.0, and the temperature can be easily obtained by washing with warm water having a temperature of 78 to 105 ° C, preferably 80 to 100 ° C, more preferably 80 to 90 ° C. .

Examples of the weakly basic solution used when washing the above carbonic acid diester include sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium carbonate, potassium carbonate, ammonium hydroxide, sodium hydrogen carbonate,
An aqueous solution of potassium hydrogen carbonate, tetramethylammonium hydroxide or the like is used, and among these, an aqueous solution of sodium hydrogen carbonate, sodium carbonate, potassium hydrogen carbonate, potassium carbonate, sodium hydrogen carbonate, potassium hydrogen carbonate or the like is particularly preferable.

After washing the carbonic acid diester with warm water as described above,
Further, it is preferable to use it after distillation.

Further, when a carbonic acid diester that does not depend on the phosgene method, for example, a carbonic acid diester obtained from a dialkyl carbonate, is used, the effect of washing with warm water can be suppressed to 2 ppm or less of hydrolyzable chlorine even by only distillation depending on the case.

Further, in the present invention, in addition to setting the total hydrolyzable chlorine content contained in the aromatic organic dihydroxyl compound and the carbonic acid diester to 3 ppm or less as described above, the aromatic organic dihydroxyl group described above is also added. The total sodium ion content in the compound and carbonic acid diester is 1.0 pp.
m preferably 0.8 ppm or less, more preferably 0.6 ppm
By further setting the iron ion content to 1.0 ppm or less, preferably 0.8 ppm or less, and more preferably 0.6 ppm or less, a polycarbonate without further coloring can be obtained.

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

To reduce the sodium ion content and the iron ion content contained in the aromatic organic dihydroxyl compound and the carbonic acid diester as described above to the above values or less, distillation,
Purification such as recrystallization may be adopted.

In the present invention, a conventionally known catalyst or a catalyst newly developed by the present inventors is used in producing a polycarbonate by melt polycondensation of the aromatic organic dihydroxyl compound and the carbonic acid diester as described above. be able to. For example, Japanese Patent Publication No. 36-694 or Japanese Patent Publication No. 3694
-13942, catalysts, specifically, alkali metals such as lithium, sodium and potassium, alkaline earth metals such as magnesium, calcium and barium, zinc, cadmium, tin, antimony, lead, manganese and cobalt. , Acetates, carbonates of metals such as nickel,
A borate, an oxide, a hydroxide, a hydride, an alcoholate, or the like is used, and a combination system of a nitrogen-containing basic compound and boric acid or borate ester, a phosphorus compound, or the like is also used.

These catalysts are preferably used in an amount of 10 ⁻⁶ to 10 ⁻¹ mol, preferably 10 ⁻⁵ to 10 ⁻² mol, based on 1 mol of the aromatic organic dihydroxyl compound used as a raw material.

The particularly preferred catalyst system is described in detail below.

In the present invention, in producing a polycarbonate by melt polycondensation of an aromatic organic dihydroxyl compound and a carbonic acid diester, (a) a nitrogen-containing basic compound and (b) an alkali metal compound or an alkaline earth metal compound (c ) Among boric acid or borate esters (a) and (b),
It is particularly preferable to use a catalyst consisting of (a) and (c), (b) and (c) or (a), (b) and (c).

Specific examples of the (a) nitrogen-containing basic compound include tetramethylammonium hydroxide (Me ₄ NOH), tetraethylammonium hydroxide (Et ₄ NOH), tetrabutylammonium hydroxide (Bu ₄ NOH) and trimethylbenzyl. Ammonium hydroxide Such as tetraalkyl or aryl, araryl ammonium hydroxides, tertiary amines such as trimethylamine, triethylamine, dimethylbenzylamine, triphenylamine, R ₂ NH (wherein R is alkyl such as methyl or ethyl, phenyl, toluyl) Secondary aryls such as aryl groups, etc., RN
Primary amines represented by H ₂ (where R is the same as above), or ammonia, tetramethylammonium borohydride (Me ₄ NBH ₄ ), tetrabutylammonium borohydride (Bu ₄ NBH ₄ ), tetrabutylammonium Tetraphenylborate (Bu ₄ NBPh ₄ ), Tetramethylammonium tetraphenylborate (Me ₄ NBP
A basic salt such as h ₄ ) is used.

Of these, tetraalkylammonium hydroxides are particularly preferable.

As the (b) 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 phenyl borohydride, lithium bisphenol A, Salts such as sodium, potassium, sodium benzoate, potassium benzoate, lithium benzoate, disodium hydrogen phosphate, dipotassium hydrogen phosphate, dilithium hydrogen phosphate and the like are used.

Further, as the (b) alkaline earth metal compound, specifically, calcium hydroxide, barium hydroxide, magnesium hydroxide, strontium hydroxide, calcium hydrogen carbonate,
Barium hydrogen carbonate, magnesium hydrogen carbonate, strontium hydrogen carbonate, calcium carbonate, barium carbonate, magnesium carbonate, strontium carbonate, calcium acetate, barium acetate, magnesium acetate, strontium acetate,
Calcium stearate, barium stearate, magnesium stearate, strontium stearate, etc. are used.

Examples of the boric acid or boric acid ester (c) include boric acid or the general formula B (OR) _n (OH) _3−n (wherein R is alkyl such as methyl or ethyl, aryl such as phenyl, and the like). Is 1, 2 or 3).

Specific examples of such boric acid ester include trimethyl borate, triethyl borate, tributyl borate,
Trihexyl borate, triheptyl borate, triphenyl borate, tritolyl borate, trinaphthyl borate and the like are used.

When the above-mentioned (a) nitrogen-containing basic compound is used, it is used in an amount of 10 mol with respect to 1 mol of the aromatic organic dihydroxy compound.
^-6 to 10 ^-1 mol, preferably 10 ^-5 to 10 ^-2 mol, and in the case of using (b) an alkali metal compound or an alkaline earth metal compound, 10 ^-8 to 10 ^-4 mol, preferably 10 ^{−. 7-10} especially preferred in an amount of ⁴ mol is used in ^{10-7 to 10-5} mol amount, and (c) if the boric acid or boric acid esters are used ^{10 -8} to
It is used in an amount of 10 ⁻¹ mol, preferably 10 ⁻⁷ to 10 ⁻² mol, particularly preferably 10 ⁻⁶ to 10 ⁻⁴ mol.

When the amount of the (a) nitrogen-containing basic compound is 10 ⁻⁶ to 10 ⁻¹ mol per 1 mol of the aromatic organic dihydroxyl compound,
It is preferable in that the transesterification reaction and the polymerization reaction proceed at a sufficient rate, and a polycarbonate excellent in hue, heat resistance and water resistance can be obtained.

When the amount of the (b) alkali metal compound or alkaline earth metal compound is 10 ⁻⁸ to 10 ⁻⁴ mol with respect to 1 mol of the aromatic organic dihydroxyl compound, the polymerization activity can be increased, and It is preferable in that a polycarbonate excellent in hue, heat resistance and water resistance can be obtained.

Further, when the amount of (c) boric acid or boric acid ester is 10 ^-8 to 10 ^-1 mol per 1 mol of the aromatic organic dihydroxyl compound, a decrease in molecular weight after heat aging is less likely to occur,
Further, it is preferable in that 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 boric acid ester (a) and (b), (a) and ( c),
The catalyst consisting of (b) and (c) or (a), (b) and (c) has a high polymerization activity and can form a high molecular weight polycarbonate, and the obtained polycarbonate is heat resistant. It also has excellent water resistance, improved color tone, and excellent transparency.

In the present invention, the polycondensation reaction between the aromatic organic dihydroxyl compound and the carbonic acid diester is carried out under the same conditions as the conventionally known polycondensation reaction conditions between the aromatic organic dihydroxyl compound and the carbonic acid diester. However, specifically, the reaction in the first step is carried out at 80 to 250 ° C., preferably 100 to 23 ° C.
0 ° C, more preferably 0 to 5 at a temperature of 120 to 190 ° C.
Time preferably 0 to 4 hours, more preferably 0.25 to
Both are reacted at atmospheric pressure for 3 hours. Then, the reaction system is decompressed and the reaction temperature is raised to carry out the reaction between the aromatic organic dihydroxyl compound and the carbonic acid diester, and finally 1 mmHg.
A polycondensation reaction between an aromatic organic dihydroxyl compound and a carbonic acid diester is carried out at a temperature of 240 to 320 ° C. under the following reduced pressure.

The above-mentioned reaction between the aromatic organic dihydroxyl compound and the carbonic acid diester may be carried out continuously or batchwise. Further, the reaction apparatus used for carrying out the above reaction may be a tank type, a tube type or a column type.

EFFECTS OF THE INVENTION In the present invention, when a polycarbonate is produced, the hydrolyzable chlorine content contained in the aromatic organic dihydroxyl compound and carbonic acid diester used as a raw material, and the total chlorine content is set to a specific value or less, and further Since the content of sodium ions and iron ions contained in raw materials such as is below a specific value, it is possible to obtain a polycarbonate excellent in color tone, heat resistance, water resistance and boiling water resistance without being colored yellow or the like. You can

The present invention will be described above with reference to examples, but the present invention is not limited to these examples.

Example The physical properties of the polycarbonates obtained in the following examples were measured as follows.

Intrinsic viscosity (IV): in methylene chloride (0.5 dl / g) 20 ° C
Was measured using an Ubbelohde viscometer.

Hue (b value): The Lab value of a 2 mm thick pressed sheet is compared with the Color and Color Defference Meter N of Nippon Denshoku Industries Co., Ltd.
It was measured by a transmission method using D-1001 DP, and b value was used as a measure of yellowness.

Heat aging test: 4.5 g of pellets dried at 120 ° C. and 400 mmHg for 12 hours were weighed in a Teflon Petri dish (40 mmφ), and then 250 ° C. gear oven (GHPS-212 Tabai Seisakusho,
After maintaining for 16 hours at an air substitution rate of 71.6 times / hour), the mixture was gradually cooled to room temperature. This sample was made into a 2 mm thick pressed sheet, and this sheet was used to obtain hue (b value) and IV.
Was measured.

Boiling water test: A 5 mm wide and 5 cm long dumbbell was punched out from a 0.5 mm thick press sheet and immersed in boiling water for 1 day.
Remove after 3 and 7 days. Within 1 hour after taking out, a tensile test was performed with an Instron 1132 at a chuck distance of 30 mm, a pulling speed of 50 mm / min, and a measuring range of 50 kg to measure elongation (%).

Press sheet preparation conditions: 120 ° C, 400 mmHg, pellets dried for 12 hours at 280 ° C, after preheating for 10 minutes, 280
It was pressed at 100 ° C./cm ³ for 5 minutes at 0 ° C. and cold pressed for 5 minutes at room temperature.

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

Sodium content: Measured by an atomic absorption method (Hitachi, 180-80) using a sample of 20 g.

Iron content: Inductively coupled plasma emission spectrometry using a sample of 20 g (Nippon Jarrell Ash, NJA ICPA 57
It was measured in 5).

Example 1 Diphenyl carbonate (manufactured by Bayer) having a hydrolyzable chlorine content of 5.9 ppm was washed with warm water having a pH of 7.0 at 80 ° C., and then distilled under reduced pressure to hydrolyze at a recovery rate of 90%. Diphenyl carbonate with a possible chlorine content of 0.3 ppm was obtained. A glass reactor was used as the reaction vessel, and the diphenyl carbonate 51.
36g (0.24mol) and hydrolyzable chlorine content 0.2pp
45.6 g (0.2 mol) of m bisphenol A (manufactured by GE)
And boric acid H ₃ BO ₃ (Wako reagent special grade) 3.1 mg (2.5 × 1
0 ^-4 mol / BPA 1 mol) under N ₂ atmosphere at 180 ° C for 76
The mixture was stirred at 0 mmHg for 30 minutes. Then, tetramethylammonium hydroxide Me ₄ NOH 15% aqueous solution (manufactured by Toyo Gosei Co., Ltd.) 30.4 mg (Me ₄ NOH 2.5 × 10 ⁻⁴ mol / BPA)
1 mol) and sodium hydrogencarbonate NaHCO ₃ (0.42 mg of Wako reagent special grade (0.25 × 10 ^-4 mol / BPA 1 mol),
Further, the mixture was stirred at 180 ° C. under N ₂ atmosphere for 30 minutes to carry out a transesterification reaction.

After that, the temperature is raised to 210 ° C, the pressure is gradually reduced to 200 mmHg, the temperature is further raised to 240 ° C for 1 hour, and the pressure is increased to 200 mmHg for 2 hours.
0 minutes, gradually reduce the pressure to 150 mmHg, 20 minutes, 10 more minutes
20 minutes after decompression to 0 mmHg, decompression to 15 mmHg and 0.5
After reacting for a period of time, the temperature is raised to 270 ° C. and finally 0.5
The pressure was reduced to mmHg and the reaction was performed for 2.5 hours. IV is 0.5
A polycarbonate of 5 dl / g was obtained. The b value of this polycarbonate was 1.3.

The results are shown in Table 1.

Examples 2 to 3 In Example 1, DPCs shown in Table 1 having different hydrolyzable chlorine content, sodium ion content and iron ion content were obtained by changing the degree of purification of diphenyl carbonate (recovery rate under reduced pressure distillation). Polymerization was carried out by the method described in Example 1 to obtain a polycarbonate.

The results are shown in Table 1.

Example 4 In Example 1, dimethyl carbonate was used as a raw material instead of Bayer diphenyl carbonate.
Polymerization was carried out by the method described in Example 1 except that diphenyl carbonate produced by Eni was used.

The results are shown in Table 1.

Comparative Example 1 Polymerization was carried out by the method described in Example 1 except that crude diphenyl carbonate was used in Example 1.

The results are shown in Table 1.

Comparative Example 2 Polymerization was carried out by the method described in Example 1, except that in Example 1, undistilled diphenyl carbonate from Eni was used instead of using diphenyl carbonate from Bayer.

The results are shown in Table 1.

Example 5 Diphenyl carbonate (manufactured by Bayer) having a hydrolyzable chlorine content of 5.9 ppm was washed twice with warm water having a pH of 7.0 at 80 ° C., and then distilled under reduced pressure to obtain a recovery rate of 90%. Hydrolyzable diphenyl carbonate having a chlorine content of 0.1 ppm or less was obtained. A glass reactor was used as a reaction vessel, and 143.8 g (0.672 mol) of this diphenyl carbonate was used in a system in which the stirring rod was made of Ni, and bisphenol A having a hydrolyzable chlorine content of 0.1 ppm or less (manufactured by Nippon GE Plastics (136. 8 g (0.600 mol) and boric acid H ₃ BO ₃ , 3% aqueous solution 3.0 mg (H ₃ BO ₃ 0.025 × 10
^-4 mol / BPA 1 mol) was heated to 180 ° C. under N ₂ atmosphere. Thereafter, 91.2 mg of a 15% aqueous solution of tetramethylammonium hydroxide (Me ₄ NOH) (manufactured by Toyo Gosei Co., Ltd.)
(Me ₄ NOH 2.5 × 10 ^-4 mol / BPA 1 mol), sodium hydroxide (NaOH) 0.1% aqueous solution 24.0 mg (0.010 × 10 ^-4 mol / B)
PA 1mol) was added and the temperature was further increased to 180 ° C under N ₂ atmosphere 3
After stirring for 0 minutes, transesterification reaction was carried out.

After that, the temperature is raised to 210 ° C, the pressure is gradually reduced to 200 mmHg, and the temperature is further raised to 240 ° C for 1 hour under the conditions,
20 minutes at 00 mmHg, then gradually depressurize to 150 mmHg for 20 minutes, depressurize to 15 mmHg and react for 0.5 hours, then raise the temperature to 270 ° C. and finally depressurize to 0.5 mmHg to 2.5 Reacted for hours. A polycarbonate having an IV of 0.55 dl / g was obtained almost quantitatively. The b value of this polycarbonate was 0.7.

The results are shown in Table 2.

Examples 6 to 7 In Examples 5, DPCs shown in Table 2 having different hydrolyzable chlorine content, sodium ion content, and iron ion content were obtained by changing the degree of purification of diphenyl carbonate (recovery rate under reduced pressure distillation). Polymerization was carried out by the method described in Example 5 to obtain a polycarbonate.

The results are shown in Table 2.

Example 8 Example 5 was repeated, except that diphenyl carbonate produced from dimethyl carbonate as a raw material was distilled instead of diphenyl carbonate in Example 5.
Polymerization was carried out by the method described in.

The results are shown in Table 2.

Example 9 In Example 5, sodium hydroxide (NaOH) 0.1%
Sodium bicarbonate (NaHCO ₃ ) 0.2% instead of aqueous solution
Aqueous solution 50.4 mg (NaHCO ₃ 0.02 × 10 ^-4 mol / BPA 1 mol)
Polymerization was carried out by the method described in Example 5 except that was used.

The results are shown in Table 2.

Example 10 In Example 5, sodium hydroxide (NaOH) 0.1%
Lithium stearate (C ₁₇ H ₃₅ COOL
i) 14.8% aqueous solution 34.8 mg (C ₁₇ H ₃₅ COOLi 0.02 × 10 ^-4 mol
Polymerization was carried out by the method described in Example 5, except that / BPA (1 mol) was used.

The results are shown in Table 2.

Example 11 In Example 5, sodium hydroxide (NaOH) 0.1%
Sodium benzoate instead of aqueous solution 0.2% aqueous solution 43.2 mg Polymerization was carried out by the method described in Example 5 except that was used.

The results are shown in Table 3.

Example 12 In Example 5, sodium hydroxide (NaOH) 0.1%
Sodium dihydrogen phosphate (Na ₂ HPO ₄ ) instead of aqueous solution
0.1% aqueous solution 42.6 mg (Na ₂ HPO ₄ 0.005 × 10 ^-4 mol / BP
Polymerization was carried out by the method described in Example 5, except that A 1 mol) was used.

The results are shown in Table 3.

Example 13 In Example 5, sodium hydroxide (NaOH) 0.1%
Disodium salt of bisphenol A instead of aqueous solution 0.2% tetrahydrofuran solution 39.9 mg Polymerization was carried out by the method described in Example 5 except that was used.

The results are shown in Table 3.

Comparative Example 3 Polymerization was carried out by the method described in Example 5 except that crude diphenyl carbonate was used in Example 5.

The results are shown in Table 3.

Comparative Example 4 Instead of using the diphenyl carbonate of Example 5, En
Polymerization was carried out by the method described in Example 5 except that undistilled diphenyl carbonate manufactured by Company i was used.

The results are shown in Table 3.

Claims (3)

[Claims] 1. When melt-polycondensing an aromatic organic dihydroxyl compound and a carbonic acid diester to produce a polycarbonate, the total hydrolyzable chlorine content contained in the above-mentioned monomers is within the following range. Method for producing a polycarbonate characterized by using an aromatic organic dihydroxyl compound and a carbonic acid diester in: Hydrolyzable chlorine content: 3 ppm or less 2. A carbonic acid diester as a raw material is adjusted to pH 6.0.
~ 9.0 and washed with warm water at 78-150 ° C to increase the hydrolyzable chlorine content of the carbonic acid diester to 1 pp.
The manufacturing method according to claim 1, wherein the manufacturing method is m or less. 3. When producing a polycarbonate by melt-polycondensing an aromatic organic dihydroxyl compound and a carbonic acid diester, the total hydrolyzable chlorine content, sodium ion content and Method for producing a polycarbonate characterized by using an aromatic organic dihydroxy compound and a carbonic acid diester, each having an iron ion content in the following range: Hydrolyzable chlorine content: 3 ppm or less Sodium ion: 1 0.0ppm or less Iron ion: 1.0ppm or less