JP2000219733A - Aromatic polycarbonate - Google Patents

Abstract

(57) [Problem] To provide an aromatic polycarbonate which is excellent in transparency and color tone because of little inclusion of a crystallized substance. A number average molecular weight of 5 produced by a transesterification process between an aromatic dihydroxy compound and a carbonic acid diester is disclosed.
300 or more aromatic polycarbonates, wherein 220
An aromatic polycarbonate having a crystallinity of 10% or less after isothermal crystallization at 20 ° C. under normal pressure and nitrogen for 20 hours.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention provides an aromatic polycarbonate which is produced by a transesterification method between an aromatic dihydroxy compound and a carbonic acid diester, and which is excellent in transparency and color tone because of little inclusion of crystallized substances. It is about doing.

[0002]

2. Description of the Related Art Aromatic polycarbonate is generally an amorphous polymer, and is used as a transparent material taking advantage of its characteristics. The so-called transesterification method for producing a polycarbonate by polycondensing a carbonic acid diester and an aromatic dihydroxy compound has a relatively simple process as compared with the phosgene method (interfacial polymerization method), and requires less operation and cost. In addition to being able to demonstrate the advantage, toxic phosgene,
The use of a halogen-based solvent such as methylene chloride is excellent in terms of environmental protection.

However, in the production by the transesterification method,
The catalyst or oligomer used as a crystal nucleus and the polymer is exposed to a temperature higher than the glass transition temperature for a long time, so that the crystal may easily grow. The grown crystal causes problems such as blocking a manufacturing apparatus, mixing into a product, lowering the transparency of the product, and increasing errors during recording / reproduction in optical applications. Regarding prevention of crystal formation when starting the polymerization equipment,
Japanese Patent Application Laid-Open No. H10-147637 discloses that a temperature rising rate of a polymerization apparatus is set to a specific range. In addition, Japanese Patent Application Laid-Open No. 6-65365 discloses that the temperature of a heating medium in a polymerization tank is set to a specific temperature range in order to reduce coloring of a polymer. However, these proposed methods have been insufficient to suppress the generation of crystals generated during long-time operation and to obtain a polymer having a good color tone.

[0004]

SUMMARY OF THE INVENTION The present invention is excellent in transparency due to less inclusion of crystallized substances than in the transesterification method between an aromatic dihydroxy compound and a carbonic acid diester,
It is another object of the present invention to provide an aromatic polycarbonate excellent in color tone.

[0005]

Means for Solving the Problems The present inventors have found that in a product,
In particular, as a result of diligent studies on the causes of optical materials such as optical discs that reduce the transparency and cause recording / reproducing errors, the prevention of microcrystals or crystal nuclei from being mixed into the polymer and the crystallization of the polymer It has been found that by setting the degree to a specific value or less, an aromatic polycarbonate excellent in transparency and color tone can be obtained, and the present invention has been completed.

That is, the present invention relates to an aromatic polycarbonate having a number average molecular weight of 5300 or more, particularly a number average molecular weight of 5300 to 9000, produced by a transesterification method between an aromatic dihydroxy compound and a carbonic acid diester. The present invention provides an aromatic polycarbonate having a crystallinity of 10% or less after an isothermal crystallization treatment at normal pressure and under nitrogen for 20 hours.

[0007] The present invention also provides a number average molecular weight (Mn) of 30.
The temperature (T: unit ° C) of a pipe through which an aromatic polycarbonate having a molecular weight of 00 or more and less than 5300 passes is determined by the molecular weight (Mn).
Accordingly, the present invention provides an aromatic polycarbonate characterized by being produced within a temperature range represented by the following formula (1) and at a temperature of 240 ° C. or more and 320 ° C. or less. 3.6 × 10 ⁵ ≦ (−4 Mn ² + 4.2 × 10 ⁴ Mn−5.0 × 10 ⁷ ) / (T−140) ≦ 5.4 × 10 ⁵ (1)

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described specifically. The aromatic polycarbonate of the present invention has a number average molecular weight of 5300 or more, and at 220 ° C., normal pressure,
10% crystallinity after isothermal crystallization treatment under nitrogen for 20 hours
It must be: Preferably, the degree of crystallinity is 5% or less, more preferably 3% or less. In such a polycarbonate, foreign matter such as a crystallized substance or a crystal nucleus is extremely little mixed. Therefore, when formed into a molded product or sheet, a product having extremely excellent transparency can be obtained. In addition, when used for an optical disk substrate or the like, recording / reproducing errors are significantly reduced, so that it is particularly preferable. As a material for such an optical application, a number average molecular weight of 5300 to 900 is used.
0 is preferred. When the number average molecular weight is less than 5300, the mechanical strength is insufficient, which is not preferable. For optical applications,
When the number average molecular weight exceeds 9000, the fluidity is lowered and the birefringence is increased.

Here, the degree of crystallinity is the degree of crystallinity after a predetermined isothermal crystallization treatment, and can be determined by measuring the heat of fusion and setting the heat of fusion of a complete crystal to 100% (J. Po.
Lym. Sci. Polym. Lett. Ed., 8, 645 (1970)). Further, the predetermined isothermal crystallization treatment is carried out by maintaining at a normal pressure and a temperature of 220 ° C. for 20 hours under a nitrogen atmosphere of a nitrogen seal or a nitrogen flow. In practice, it is general that the polymer is contained in a glass container or a metal pan of a DSC device, and the crystallization treatment is performed.

[0010] Crystals mixed into the aromatic polycarbonate are generated from crystal nuclei, microcrystals, and other foreign matter which promotes crystal formation. Of these foreign matters, a large one is provided with a filter in each part of the manufacturing process by a known method. Can be removed. However, since the crystal nucleus is very fine, it cannot be sufficiently filtered by a filter alone. Even if an apparently transparent polymer is obtained, if crystal nuclei are mixed, crystals gradually grow over time after molding into a product, and the transparency of the product is lost. Such crystal nuclei tend to grow when a polymer having a specific molecular weight is subjected to a long-term thermal history in a specific temperature range. During the production process, by controlling the temperature of the piping where the polymer is most likely to stay at a specific value according to the number average molecular weight, it is possible to suppress the formation of crystals and to keep the color tone of the polymer favorable. That is, the temperature of the pipe through which the aromatic polycarbonate having a number average molecular weight (Mn) of 3000 or more and less than 5300 passes (T:
Unit) according to the number average molecular weight of the following formula (1)
Within the temperature range indicated by, and at least 240 ° C and 320 ° C
It is preferable to maintain the following. 3.6 × 10 ⁵ ≦ (−4 Mn ² + 4.2 × 10 ⁴ Mn−5.0 × 10 ⁷ ) / (T−140) ≦ 5.4 × 10 ⁵ (1)

In the equation (1), "(-4Mn^Two +4.
2 × 10^Four Mn-5.0 × 10⁷ ) / (T-140) "
Is 5.4 × 10^Five Exceeds the pipe temperature
The molecular weight is too low compared to the average molecular weight, and crystals are easily formed.
May cause a decrease in product transparency and blockage of piping.
It will be cool. 3.6 × 10^Five If less than the relative pipe temperature
Too high, causing polymer coloration
I don't. "(-4Mn ^Two + 4.2 × 10^Four Mn-5.0
× 10⁷ ) / (T-140) ”is 3.9 × 1
0^Five More preferably, 4.1 × 10^Five Above is particularly preferred
No. The upper limit is 5.1 × 10^Five The following is preferable,
4.7 × 10^Five The following are particularly preferred. Number average molecular weight is 3
Oligomers less than 000 do not form crystals at high temperatures
Or, if formed, the crystals melt in the subsequent polymerization process
You. When the number average molecular weight is 5300 or more, the crystal growth rate is slow.
Therefore, no crystals are formed, or
The crystals melt during the polymerization process. However, the number average molecular weight is
With an aromatic polycarbonate of 3000 or more and less than 5300
Is within the range satisfying the expression (1) because the crystal growth rate is high.
If not maintained at the pipe temperature, remarkable crystals will
The rimer is colored.

In the present invention, a pipe to be temperature-controlled is provided between the first reactor and the last reactor, if necessary, with another reactor and / or a preheating tank, a hold tank (temporary storage tank) or the like. This is a pipe through which a polymer having a number average molecular weight of 3,000 or more and less than 5,300 passes through the pipes connected via the intermediate tank. Further, in the present invention, not only the pipe itself, but also valves, pumps, and the like provided in the middle of the pipe,
The parts that come into contact with the passing polymer, such as bypass pipes, pressure gauges, flow meters, and other measurement devices provided for analysis and emergency use, should be considered in the same way as the pipes themselves and subject to temperature control. preferable. Further, in the present invention, the temperature of the pipe refers to the temperature of the outer wall surface of the pipe through which the polymer passes. If the piping is heated with a heating medium, generally
It becomes almost equal to the heating medium temperature. The temperature can be easily measured by a commonly used method.

[0013] Since the pipes usually have no forced stirring equipment and the flow path tends to be complicated, the polymer is more likely to stay as compared with the reaction tank having the stirring equipment. Crystals are easily generated. Therefore, the piping is designed in consideration of the diameter, length, surface roughness, curvature, etc. so that the stagnation portion is not formed as much as possible, and the structure is such that the piping surface is uniformly heated and kept warm so that there is no low-temperature portion. It is preferable to adopt a material that suppresses and eliminates the generation of crystals and crystal nuclei.

The method of heating the pipe may be any known method, such as heating with a heating medium using oil or steam, or electric heating with a casting heater. In addition, as long as the pipe temperature can be maintained, only the heat retention may be used. The material of these pipes is not particularly limited, but is generally made of stainless steel, for example, SUS30.
4, SUS304L, SUS310S, SUS316,
SUS316L and the like. The pipe surface may be subjected to various treatments, for example, buff polishing, electrolytic polishing, acid treatment, heat treatment, various plating, coating treatment and the like.

As raw materials for producing the aromatic polycarbonate according to the present invention, a carbonic acid diester and an aromatic dihydroxy compound are used. The carbonic acid diester is represented by the formula (2).

[0016]

Embedded image

(Wherein A and A ′ each have 1 to 18 carbon atoms)
Is an aliphatic group or an aromatic group which may be substituted, and A and A ′ may be the same or different. )

Specific examples of the carbonic diester represented by the formula (2) include, for example, substituted diphenyl carbonates such as dimethyl carbonate, diethyl carbonate, di-t-butyl carbonate, diphenyl carbonate and ditolyl carbonate. Preferred are diphenyl carbonate and substituted diphenyl carbonate, with diphenyl carbonate being particularly preferred. These carbonic acid diesters may be used alone or in combination of two or more.

A dicarboxylic acid or a dicarboxylic acid ester may be used in an amount of preferably 50% or less, more preferably 30% by mole or less, together with the above-mentioned carbonic acid diester. As such a dicarboxylic acid or dicarboxylic acid ester, terephthalic acid, isophthalic acid, diphenyl terephthalate, diphenyl isophthalate and the like are used. When such a carboxylic acid or a carboxylic acid ester is used in combination with a carbonic acid diester, a polyester carbonate is obtained.

The aromatic dihydroxy compound as another raw material is represented by the formula (3).

[0021]

Embedded image

(Wherein B is a divalent hydrocarbon group having 1 to 15 carbon atoms, a halogen-substituted divalent hydrocarbon group,
-S- group, -SO ₂ - group, -SO- group, -O- group, or -
X represents a CO- group, and X represents a halogen atom, having 1 to 14 carbon atoms.
Alkyl group, aryl group having 6 to 18 carbon atoms, 1 carbon atom
Oxyalkyl group or oxyaryl group having 6 to 18 carbon atoms. m is 0 or 1, y is 0 to 4
Is an integer. )

Examples of the aromatic dihydroxy compound represented by the formula (3) include 2,2-bis (4-hydroxyphenyl) propane [= bisphenol A] and 2,2-bis
Bis (4-hydroxy-3,5-dimethylphenyl) propane, 2,2-bis (4-hydroxy-3,5-diethylphenyl) propane, 2,2-bis (4-hydroxy- (3,5-diphenyl) ) Phenyl) propane, 2,
2-bis (4-hydroxy-3,5-dibromophenyl) propane, 2,2-bis (4-hydroxyphenyl) pentane, 2,4′-dihydroxy-diphenylmethane, bis (4-hydroxyphenyl) methane, bis ( 4-hydroxy-5-nitrophenyl) methane, 1,
1-bis (4-hydroxyphenyl) ethane, 3,3-
Bis (4-hydroxyphenyl) pentane, 1,1-bis (4-hydroxyphenyl) cyclohexane, bis (4-hydroxyphenyl) sulfone, 2,4′-dihydroxydiphenylsulfone, bis (4-hydroxyphenyl) sulfide, 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxy-3,3'-dichlorodiphenyl ether, 4,4'-dihydroxy-
Examples thereof include 2,5-diethoxydiphenyl ether. Among these, 2,2-bis (4-hydroxyphenyl) propane is preferable. These aromatic dihydroxy compounds may be used alone or in combination of two or more.
Can be used.

The mixing ratio of the carbonic acid diester and the aromatic dihydroxy compound is determined by the desired molecular weight of the aromatic polycarbonate and the terminal hydroxyl group content. The amount of terminal hydroxyl groups greatly affects the thermal stability and hydrolysis stability of the product polycarbonate, and must be 1,000 ppm or less in order to have practical physical properties. Therefore, it is common to use a carbonate diester in an equimolar amount or more with respect to 1 mole of the aromatic dihydroxy compound, and 1.01 to 1.30 mole, preferably 1.01 to 1.30 mole.
Preferably, it is used in an amount of 1.20 mol.

When an aromatic polycarbonate is produced by the transesterification method, a transesterification catalyst is usually used. As the transesterification catalyst, an alkali metal compound and / or an alkaline earth metal compound are mainly used, and a basic compound such as a basic boron compound, a basic phosphorus compound, a basic ammonium compound, or an amine compound is supplementarily used. It is also possible to use together. These catalysts may be used alone or in combination of two or more.

The amount of the catalyst is usually 1 × 10 ⁻⁸ to 1 × 10 ⁻⁵ mol per mol of the aromatic dihydroxy compound. If less than this amount, the given molecular weight,
The polymerization activity required for a long period of time to produce a polycarbonate having a terminal hydroxy group cannot be obtained. If the amount is larger than this amount, the polymer hue deteriorates, and the amount of foreign substances due to the generation of gel tends to increase. In particular, alkali metal compounds and / or
When an alkaline earth metal compound is used, the amount of the metal is preferably in the range of 1 × 10 ⁻⁸ to 2 × 10 ⁻⁶ mol, particularly preferably in the range of 0.5 × 10 ⁻⁷ to 1 × 10 ⁻⁶ mol. preferable.

As the alkali metal compound, lithium,
Inorganic alkali metal compounds such as sodium, potassium, rubidium and cesium hydroxides, hydrogen carbonates, carbonates, acetates, hydrogen phosphates and phenyl phosphates; organic acids such as stearic acid and benzoic acid; methanol And organic alkali metal compounds such as salts with alcohols such as ethanol, phenolic acid, and phenols such as bisphenol A.

Examples of the alkaline earth metal compound include inorganic alkaline earth metal compounds such as beryllium, calcium, magnesium, strontium and barium hydroxides, hydrogen carbonates, carbonates and acetates, organic acids, alcohols and the like. Organic alkaline earth metal compounds such as salts with phenols and the like can be mentioned.

Specific examples of the basic boron compound include tetramethyl boron, tetraethyl boron, tetrapropyl boron, tetrabutyl boron, trimethylethyl boron, trimethylbenzyl boron, trimethylphenyl boron, triethylmethyl boron, triethylbenzyl boron, triethylphenyl Hydrides such as boron, tributylbenzylboron, tributylphenylboron, tetraphenylboron, benzyltriphenylboron, methyltriphenylboron, butyltriphenylboron,
Examples thereof include a sodium salt, a potassium salt, a lithium salt, a calcium salt, a magnesium salt, a barium salt, and a strontium salt.

Examples of the basic phosphorus compound include triethylphosphine, tri-n-propylphosphine, triisopropylphosphine, tri-n-butylphosphine, triphenylphosphine, tributylphosphine, and the like.
Alternatively, quaternary phosphonium salts and the like can be mentioned.

Examples of the basic ammonium compound include tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, trimethylethylammonium hydroxide,
Trimethylbenzylammonium hydroxide, trimethylphenylammonium hydroxide, triethylmethylammonium hydroxide, triethylbenzylammonium hydroxide, triethylphenylammonium hydroxide, tributylbenzylammonium hydroxide, tributylphenylammonium hydroxide, tetraphenylammonium hydroxide, benzyltrimoxide Phenylammonium hydroxide, methyltriphenylammonium hydroxide, butyltriphenylammonium hydroxide and the like.

Examples of the amine compound include 4-aminopyridine, 2-aminopyridine, N, N-dimethyl-4-aminopyridine, 4-diethylaminopyridine,
2-hydroxypyridine, 2-methoxypyridine, 4-
Methoxypyridine, 2-dimethylaminoimidazole,
Examples include 2-methoxyimidazole, imidazole, 2-mercaptoimidazole, 2-methylimidazole, aminoquinoline and the like.

The aromatic polycarbonate of the present invention is produced in two or more steps. Generally, reaction temperature 1
The reaction is carried out at a temperature of 40 to 320 ° C. for a reaction time of 0.1 to 5 hours while the monophenol compound by-produced is continuously removed from the line while increasing the degree of pressure reduction from normal pressure. If necessary, an inert gas such as nitrogen can be passed. Also,
A fractionation tower may be provided in the reactor to return the raw materials accompanying the monophenol compound to the reaction tank. Finally, a polycondensation reaction is performed at a temperature of 250 to 320 ° C. under a reduced pressure of 2 mmHg or less to increase the molecular weight to a number average molecular weight of 14,000 or more.

The reaction system may be a batch system, a continuous system, or a combination of a batch system and a continuous system. The apparatus to be used may be any of a tank type, a tube type, and a tower type. For example, a vertical polymerization tank equipped with various stirring blades, a horizontal single-axis polymerization tank, and / or a horizontal two-axis polymerization tank A type polymerization tank or the like can be used.

The reaction is preferably carried out under substantially oxygen-free condition. For example, before starting the operation, the inside of the raw material adjusting tank, the reactor and the piping are replaced with an inert gas such as nitrogen gas.
Usually, a molten mixture of an aromatic dihydroxy compound and a carbonic acid diester is fed to a vertical reactor. The catalyst may be supplied directly to the first reaction tank on a separate line from the raw material, or may be supplied in a state of being mixed with the raw material by a static mixer or the like in a pipe before entering the first reaction tank. . If necessary, a solvent for dissolving or suspending the catalyst is used. Preferred solvents include water, acetone, phenol and the like.

The liquid supply port is preferably located at the liquid phase on the side wall of the reaction vessel, and the discharge port is preferably located at the bottom of the reaction vessel. Further, the method of continuously extracting the reaction solution from each tank is performed by a method suitable for the physical properties of the reaction solution, such as a method using a head, a method using a pressure difference, a method using a liquid sending pump such as a gear pump, or the like. Is preferred.

After completion of the polymerization, the produced aromatic polycarbonate is usually recovered as pellets.
In order to remove low molecular weight components such as monomers and by-products remaining in the resin, it is also possible to pass through a vent-type extruder.

When a catalyst such as an alkali metal compound is used, an acidic compound, particularly a sulfur-containing acidic compound, is used in an amount of 0.5 to 10 equivalents to the catalyst metal in order to neutralize the catalyst remaining in the polycarbonate. , Preferably 1 to 5 equivalents can be added. That is, usually 0.01 to 2
0 ppm, preferably 0.1 to 10 ppm, more preferably 3 to 7 ppm is added.

Examples of the sulfur-containing acidic compound include sulfonic acid, sulfinic acid and ester derivatives thereof, and specifically, p-toluenesulfonic acid, benzenesulfonic acid and dodecylbenzenesulfonic acid, methyl and ethyl thereof. , Butyl, t-butyl, octyl, dodecyl, phenyl, benzyl, esters such as phenethyl,
Examples include benzenesulfinic acid, toluenesulfinic acid, and naphthalenesulfonic acid. Of these compounds,
An ester of p-toluenesulfonic acid or an ester of benzenesulfonic acid is preferred, and two or more of these compounds may be used. Furthermore, it is preferable to use an alkali metal salt of these compounds in combination with these compounds, because the dispersibility is improved and the deactivating effect is enhanced. As the amount used together,
It is preferable to use the alkali metal salt in an amount of about 0.3 to 3 times the weight of the non-alkali metal salt.

[0040] The sulfur-containing acidic compound can be added to the polycarbonate by any method.
For example, a sulfur-containing acidic compound can be added to or dispersed in a polycarbonate in a molten or solid state, either directly or diluted with a diluent. Specifically, it can be supplied and mixed in a polycondensation reactor, a transfer line from the reactor, and an extruder, and is usually supplied into an extruder.
Further, after mixing with polycarbonate, pellets, flakes, powders or the like of polycarbonate or another kind of polymer by a mixer or the like, the mixture can be supplied to an extruder and kneaded. Among the above, it is preferable to add the stock solution of the sulfur-containing acidic compound to the polycarbonate flakes, mix them with a mixer or the like, and then add them as a master batch. Further, at the time of addition, it is preferable to control the addition amount with high accuracy using a weight feeder or the like.

In the case of performing a decompression treatment by venting with an extruder, or adding water, a heat stabilizer, a release agent, a dye, a pigment, an ultraviolet absorber, an antistatic agent, an antifogging agent, an organic / inorganic filler, and the like. When adding, these addition and treatment may be performed simultaneously with the sulfur-containing acidic compound, but it is preferable to add and knead the sulfur-containing acidic compound first.

[0042]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to Examples, but the present invention is not limited to the following Examples. The analysis was performed by the following method.

(1) Number average molecular weight (Mn) Measurement was performed using GPC (gel permeation chromatography). The calibration curve was created using standard monodisperse polystyrene. (Measurement conditions) GPC: HLC-8020 (Tosoh Corporation) Detector: Differential refractometer RI-8010 (Tosoh Corporation) Column: TSK-GEL GMH _HR (Tosoh Corporation) Solvent: Tetra Hydrofuran Temperature: 25 ° C Flow rate: 1 ml / min Conversion formula: Mpc = 0.3591 (Mps) ^1.0388 (Mpc and Mps are the molecular weights of polycarbonate and polystyrene, respectively)

(2) Hue After the polycarbonate resin was dried in a nitrogen atmosphere at 120 ° C. for 6 hours or more, an injection molded product having a thickness of 3 mm was produced using a J-100 injection molding machine manufactured by Japan Steel Works, Ltd. Machine S
The YI value was measured by C-1.

(3) Crystallinity Approximately 4 g of the polymer in a molten state after the production was placed in a test tube, and heated at 220 ° C. for 20 hours using an aluminum block bath under a nitrogen seal to carry out isothermal crystallization. The crystallinity is
Heat of fusion of sample crystal obtained by DSC (ΔH)
And the heat of fusion of perfect crystals (26.2 cal / g) (J. Po.
Lym.Sci.Polym.Lett.Ed., 8,645 (1970)) Crystallinity (%) = (ΔH / 26.2) × 100

Production Example 1 Under a nitrogen gas atmosphere, bisphenol A and diphenyl carbonate were mixed at a fixed molar ratio (DPC / BPA = 1.06).
The melt-mixed product at 140 ° C. prepared and mixed in 5) is mixed with 14
The polymer was continuously supplied to the first vertical stirring polymerization tank controlled at 210 ° C. under normal pressure and nitrogen atmosphere through a raw material introduction pipe heated to 0 ° C., and the polymer at the bottom of the tank was adjusted so that the average residence time was 60 minutes. The liquid level was kept constant while controlling the opening of the valve provided in the discharge line. At the same time as the supply of the raw material mixture was started, an aqueous cesium carbonate solution was continuously supplied as a catalyst at a flow rate of 1 × 10 ⁻⁶ mol per 1 mol of bisphenol A.

The polymerization solution discharged from the bottom of the tank was successively and continuously supplied to the second, third, and fourth vertical polymerization tanks and the fifth horizontal polymerization tank. During the reaction, the average residence time in each tank was 60
The liquid surface level was controlled so as to obtain minute amounts, and at the same time, phenol produced as a by-product was distilled off. The polymerization conditions of each reaction tank between the second and the fifth are respectively the second polymerization tank (210 ° C., 100 ° C.).
Torr), third polymerization tank (240 ° C., 15 Torr),
As the reaction progressed in the fourth polymerization tank (260 ° C., 0.5 Torr) and the fifth polymerization tank (270 ° C., 0.5 Torr), conditions were set to high temperature, high vacuum, and low stirring speed. Polycarbonate was produced at 50 kg / Hr and operated continuously for 300 hours.

[0048] Production Example 2 Catalyst phenyl phosphate disodium 1 × 10 ^-6 mol to use relative to bisphenol A1 mole as the bisphenol A and diphenyl carbonate in a constant molar ratio (DPC / BPA = 1.04) After mixing and preparing, each reaction tank condition was set to the first polymerization tank (220 ° C., 100 Torr).
r) Second polymerization tank (240 ° C., 15 Torr), third polymerization tank (265 ° C., 0.5 Torr), fourth polymerization tank (280
° C, 0.5 Torr), the fifth polymerization tank (280 ° C, 0.2 Torr)
The reaction was carried out in the same manner as in Production Example 1 except that the reaction pressure was changed to Torr).

Examples 1 to 6 and Comparative Examples 1 to 3 During the polymerization in Production Examples 1 and 2, the temperature of the piping between the reaction tanks was controlled with oil according to Table 1. Polymerization 1
After 00 hours and 240 hours, whether or not crystals were mixed in the final product was determined by molding an injection sheet of 100 × 100 × 3 mm, visually observing the degree of whitening due to the mixed crystals, and measuring the hue. . The crystallinity after isothermal crystallization was measured from the heat of fusion with a differential scanning calorimeter (DSC). The results are shown in Table 1.

[0050]

[Table 1]

[0051]

According to the present invention, it is possible to obtain a transesterified aromatic polycarbonate which prevents crystallized products from being mixed into a product, and is excellent in transparency and color tone.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Michio Kawai 1 Tohocho, Yokkaichi City, Mie Prefecture Inside Yokkaichi Office of Mitsubishi Chemical Corporation (72) Inventor Katsushige Hayashi 2-4-1 Hinagahigashi, Yokkaichi City, Mie Prefecture (72) Inventor Yuji Takeda 2-4-1, Hinagahigashi, Yokkaichi City, Mie Prefecture F-term (reference) 4J029 AA10 AB04 AC01 AD01 AD10 AE03 AE05 BB12A BB13A BB13B BB13C BD09A BF14A BG08X BG24X BH01 BH02 DA03 DB07 DB13 HA01 HC04A HC05A JA091 JA121 JA251 JB131 JB171 JC091 JC231 JC261 JC551 JC581 JC631 JC731 JF021 JF031 JF041 JF051 JF121 JF131 JF141 JF151 JF161 KB05 KD01 KD07 KD09 KE02 KE05 KH01 KH05 KJ05 LB04

Claims (3)

[Claims] 1. A number average molecular weight of 5 produced by a transesterification method between an aromatic dihydroxy compound and a carbonic acid diester.
300 or more aromatic polycarbonates, wherein 220
An aromatic polycarbonate having a crystallinity of 10% or less after isothermal crystallization at 20 ° C. under normal pressure and nitrogen for 20 hours. 2. A number average molecular weight (Mn) of 3,000 to 530.
The temperature (T: unit ° C) of the pipe through which the aromatic polycarbonate less than 0 passes is set within the temperature range represented by the following formula (1), and more than 240 ° C and less than 320 ° C according to the molecular weight (Mn). The aromatic polycarbonate according to claim 1, wherein the aromatic polycarbonate is produced while being maintained. 3.6 × 10 ⁵ ≦ (−4 Mn ² + 4.2 × 10 ⁴ Mn−5.0 × 10 ⁷ ) / (T−140) ≦ 5.4 × 10 ⁵ (1) 3. The aromatic polycarbonate according to claim 1, wherein the number average molecular weight is from 5300 to 9000.