JP3348473B2 - Aromatic polycarbonate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aromatic polycarbonate known as an engineering plastic and a method for producing the same. More specifically, the present invention relates to a high-quality aromatic polycarbonate excellent in color tone and a method for producing the same.

[0002]

2. Description of the Related Art Aromatic polycarbonate resins have excellent impact resistance as engineering plastics.
Widely used for applications that take advantage of dimensional stability and transparency. Industrial production methods include an interface method in which a dihydroxydiaryl compound such as bisphenol is reacted with phosgene, and a transesterification method in which a dihydroxydiaryl compound such as bisphenol is reacted with a diaryl carbonate such as diphenyl carbonate in a molten state (melting method). Law) is known.

[0003]

As a method for producing a diaryl carbonate such as diphenyl carbonate, many methods have been studied for transesterification of a dialkyl carbonate in the presence of phenol.
According to 1-172852, it is described that in these methods, by-product impurities having a boiling point close to that of diaryl carbonate are mixed in diaryl carbonate. Japanese Patent Application Laid-Open No. 4-100824 discloses that when producing an aromatic polycarbonate by a melting method, the xanthone content is 10 p.
A method using a diaryl carbonate that is not more than pm is described. However, it has been difficult to say that these techniques have established a sufficient technique for coloring an aromatic polycarbonate. Further, regarding the coloring of the aromatic polycarbonate, the influence of the material of the reactor has also been suggested. According to U.S. Pat. No. 4,383,092,
It has been proposed to color the aromatic polycarbonate by lining the liquid contact part of the reactor with glass or tantalum, nickel or chromium. On the other hand, Japanese Patent Application Laid-Open No. 4-332726 describes that a material having an iron component of 20% or less is used for a liquid contact part of a reactor. However, these metals were not substantial because they were expensive to use as reactor materials.

[0004]

Means for Solving the Problems The present inventors have conducted intensive studies to develop a high-quality aromatic polycarbonate having excellent color tone, and as a result, have found that an aromatic polycarbonate resin having a benzophenone derivative and an ester derivative of 100 ppm or less is used. As a result, they have found that the above problem can be solved, and have reached the present invention.

Hereinafter, the present invention will be described in detail. As the aromatic dihydroxy compound used as a raw material in the present invention, those represented by the general formula (I) are used.

[0006]

Embedded image

In the general formula (I), R ¹ and R ² each independently represent a hydrogen atom, a halogen, an alkyl group, an alkenyl group or an optionally substituted aryl group;

[0008]

Embedded image

(However, R ³ and R ⁴ each independently represent a hydrogen atom,
An alkyl group having 1 to 12 carbon atoms or 6 to 1 carbon atoms
Represents up to 2 aryl groups),

[0010]

Embedded image

(Cycloalkylene group; n is an integer from 2 to 4), -O-, -CO-, -S-, -SO- and the like. Particularly preferred are bis (4-hydroxyphenyl) methane, 1,1-bis (4-hydroxyphenyl) ethane, 1,1-bis (4-hydroxyphenyl) propane, 2,2-bis (4-hydroxy Phenyl) propane, 1,1-bis (4-hydroxyphenyl) butane, 2,2-bis (4-hydroxyphenyl)
Butane, 1,1-bis (4-hydroxyphenyl) pentane, 2,2-bis (4-hydroxyphenyl) pentane, 3,3-bis (4-hydroxyphenyl) pentane, 2,2-bis (4-hydroxy Phenyl) -4-methylpentane, 2,2-bis (3-methyl-4-hydroxyphenyl) propane, 2,2-bis (3-ethyl-
4-hydroxyphenyl) propane, 2,2-bis (3
-Isopropyl-4-hydroxyphenyl) propane,
2,2-bis (3-sec-butyl-4-hydroxyphenyl) propane, 2,2-bis (3-phenyl-4-hydroxyphenyl) propane, 2,2-bis (4-hydroxyphenyl) hexafluoropropane , Screw (4-
(Hydroxyphenyl) phenylmethane, 1,1-bis (4-hydroxyphenyl) -1-phenylethane,
1,1-bis (4-hydroxyphenyl) -1-phenylpropane, bis (4-hydroxyphenyl) diphenylmethane, bis (4-hydroxyphenyl) dibenzylmethane, 1,1-bis (4-hydroxyphenyl) -cyclo Pentane, 1,1-bis (4-hydroxyphenyl) -cyclohexane, 4,4′-dihydroxydiphenylether, 4,4′-dihydroxydiphenylsulfide, 4,4′-dihydroxydiphenylsulfoxide, 4,4′-dihydroxydiphenylsulfone And phenolphthalein. These aromatic dihydroxy compounds may be used alone or as a mixture.

The diaryl carbonate used in the present invention includes diphenyl carbonate, bis (p-chlorophenyl) carbonate, bis (o-chlorophenyl) carbonate, bis (2,4-dichlorophenyl) carbonate, bis (p-nitrophenyl) Examples thereof include carbonate, bis (o-nitrophenyl) carbonate, bisallyl carbonate of bisphenol A, and polycarbonate oligomer having a phenyl carbonate group at a terminal. Preferably, it is diphenyl carbonate. Usually, these carbonate diesters are used in an amount of 1 to 1.7 mol, preferably 1.05 to 1.5 mol, per 1 mol of the aromatic dihydroxy compound.

The content of the benzophenone derivative and the ester derivative in the aromatic polycarbonate shown in the present invention is 100 ppm or less, preferably 20 ppm or less, and more preferably 10 ppm or less. If the amounts of the benzophenone derivative and the ester derivative are above this range, the aromatic polycarbonate will be colored yellow. The benzophenone derivative of the present invention is a compound represented by the general formula (II).

[0014]

Embedded image (Wherein, R ^{5 to} R ¹⁴ each independently represent a hydrogen atom, a halogen,
Hydroxyl group, alkyl group, alkenyl group, optionally substituted aryl group, alkyloxy group, alkenyloxy group,
And a phenyloxy group which may be substituted. )

Specific examples of this include benzophenone, 3
-Methylbenzophenone, 3-vinylbenzophenone,
2,4-dimethoxybenzophenone, 4,4'-dimethoxybenzophenone, 2,2 ', 4,4'-tetrachlorobenzophenone, 2,3,4-trihydroxybenzophenone, 2,3,4,4'-tetrahydroxy Benzophenone and the like can be mentioned, and those having a higher removal effect include 2-hydroxybenzophenone, 3-hydroxybenzophenone, 4-hydroxybenzophenone, 2-hydroxy-4-methoxyxy, wherein the benzophenone derivative is mono- or dihydroxybenzophenone. Benzophenone, 2,4-dihydroxybenzophenone, 2,2′-dihydroxybenzophenone, 2,
4'-dihydroxybenzophenone, 4,4'-dihydroxybenzophenone and the like. Among them, 2,
It is preferable to remove 2'-dihydroxybenzophenone from the viewpoint of improving the color tone of the aromatic polycarbonate.
The ester derivative that deteriorates the color tone of the aromatic polycarbonate is a compound represented by the general formula (III).

[0016]

Embedded image (In the formula, R ^{5 to} R ¹⁴ represent the same groups as in the formula (II).)

Specific examples include phenyl 2-hydroxybenzoate (phenyl salicylate) and phenyl 4-hydroxybenzoate, such as phenyl 2-methylbenzoate, phenyl 3-methylbenzoate, and 4-methylbenzoic acid. Phenyl ester, 2,4-dihydroxybenzoic acid phenyl ester, 2-methylbenzoic acid-2,4-dihydroxyphenyl ester, 2-methoxybenzoic acid-4-methylphenyl ester, 2-methoxybenzoic acid-4-hydroxyphenyl ester , 2
-Hydroxybenzoic acid-4-hydroxyphenyl ester, 2,4-dihydroxybenzoic acid-4-hydroxyphenyl ester, 3-hydroxybenzoic acid-4-hydroxyphenyl ester, and the like. Examples include 2-hydroxybenzoic acid phenyl ester and 4-hydroxybenzoic acid phenyl ester.

These benzophenone derivatives and ester derivatives may have a molecular weight of less than 1,000, and may be a dimer, a trimer or the like. In order to suppress coloring, the aromatic polycarbonate preferably has a retained oxygen concentration of 100 ppm or less, more preferably 50 ppm or less. If the residual oxygen concentration exceeds 100 ppm, adverse effects such as deterioration of color tone, for example, when left in the air for a long time, or during molding, occur. The aromatic polycarbonate of the present invention has a viscosity average molecular weight of 10,000 or more, and preferably 20% or less, more preferably 10% or less, of the terminal of the polycarbonate. When the hydroxyl group terminal exceeds 20%, heat resistance and hydrolysis resistance are adversely affected, which is not preferable.

If necessary, a monosubstituted phenol as a terminal blocking group may be added to the aromatic polycarbonate of the present invention. Monofunctional phenols used for such purposes include those represented by the general formula (IV)

[0020]

Embedded image

There is a compound represented by the formula: Specific examples include cresol, methoxyphenol, tert-butylphenol, amylphenol, hexylphenol, octylphenol, cumylphenol, phenylphenol and the like. These monofunctional phenols may be added at the beginning of the polymerization or after the transesterification reaction at the beginning of the polymerization is completed.

In the process for producing an aromatic polycarbonate resin according to the present invention, a trifunctional or higher polyfunctional compound such as phloroglucin or 1,1,1-tris (4-hydroxyphenyl) -ethane is added to form a branched polycarbonate resin. It is also possible to use Further, an aromatic polyester polycarbonate resin can be obtained by adding a dicarboxylic acid such as terephthalic acid or isophthalic acid.

The transesterification catalyst which can be used in the present invention is:
Specifically, in addition to phenolates, carbonates, acetates, hydroxides, hydrides of alkali metals or alkaline earth metals, phosphorus compounds such as phenylphosphoric acid, phenylphosphorous acid and metal salts thereof, and tetramethylammonium Ammonium such as tetraphenylboronate, tetraphenylphosphonium-tetraphenylboranate, phosphonium borate salt catalyst, tetramethylammonium hydroxide, tetrabutylammonium hydroxide,
Ammonium hydroxides such as trimethylbenzylammonium hydroxide; quaternary ammonium salts such as dimethylphenylbenzylammonium chloride and benzyltributylammonium chloride; amines and salts thereof such as triethylamine, 2-methylimidazole and dimethyl-4-aminopyridine; Acid derivatives or salts thereof are exemplified.

Among these, an iminocarboxylic acid derivative or a salt thereof is particularly preferable, and may be used alone, or may be used in combination with the other catalyst described above. The iminocarboxylic acid derivative is a compound having a group represented by the general formula (V) in the molecule.

[0025]

Embedded image

(In the formula, n represents an integer of 1 to 3.) Specifically, iminodiacetic acid, iminodipropionic acid, N-
Methyliminodiacetic acid, iminodicarboxylic acid type compounds such as phenyliminodiacetic acid, nitrilotriacetic acid, nitrilotricarboxylic acid type compounds such as nitrilotripropionic acid, ethylenediaminetetraacetic acid, ethylenediaminetetrapropionic acid, propylenediaminetetraacetic acid, cyclohexanediamine Examples thereof include diaminetetracarboxylic acid type compounds such as tetraacetic acid, xylylenediaminetetraacetic acid, and glycol ether diaminetetraacetic acid, diethylenetriaminepentaacetic acid, and trimethylenetetraminehexaacetic acid.

As the metal salt of the above iminocarboxylic acid derivative, salts of various metals can be used. For example, alkali metals such as lithium, sodium and potassium can be used.
Alkaline earth metals such as beryllium, magnesium, calcium, barium, zinc, cadmium, copper, tin,
Metal salts such as lead, manganese, cobalt, nickel and the like can be mentioned.

The amount of the iminocarboxylic acid derivative or its metal salt used is about 1 × 10 −6 to 1 mol%, preferably 1 × 10 −5 mol%, based on the total amount of the aromatic dihydroxy compound used as the raw material. About 1.times.10@-2 mol%. If the amount of the catalyst is too small, the polymerization rate becomes slow, which causes coloring. Further, even if used in an excessively large amount, it may cause adverse effects on coloring, thermal stability, hydrolysis resistance and the like.

In the process for producing an aromatic polycarbonate resin of the present invention, the polycarbonate resin can be produced in a single step using a tank reactor. It is preferable to synthesize a prepolymer having a low melt viscosity by using a tank type reactor in the polycondensation step, and to increase the molecular weight of the prepolymer in the post-polycondensation step. In the post-polycondensation step, a production method having a small heat history is preferable. Examples of such a production method include a method using a horizontal twin-screw self-cleaning high-viscosity reactor, a solid-phase polymerization method, and the like. In particular, a method using a horizontal two-axis self-cleaning high-viscosity reactor is preferable.

The reaction temperature in the pre-polycondensation step is usually 1
The temperature ranges from 40 ° C. to 320 ° C., and the pressure ranges from normal pressure to 0.0001 Torr. In this step, a polycarbonate prepolymer having a viscosity average molecular weight of 5,000 to 20,000 is obtained. When the molecular weight of the prepolymer is lower than 5,000, it takes a long time to increase the molecular weight in the post-polycondensation step, which is disadvantageous in terms of productivity. If the molecular weight of the prepolymer exceeds 20,000, it must be performed at a high temperature of 330 ° C. or higher in order to prevent the melt viscosity from increasing when producing in a tank-type reactor, which is disadvantageous in terms of color tone. Become.

In order to suppress a side reaction that adversely affects the color tone, a diaryl carbonate 3
It is preferable that the reaction temperature is not raised to 240 ° C. or more when 000 ppm or more remains, and it is further preferable that the reaction temperature is not raised to 250 ° C. or more when 1000 ppm or more of the diaryl carbonate remains. After the phenol content was distilled at least 90% of the theoretical distillation amount (twice moles of the aromatic dihydroxy compound), the reaction temperature was raised to 240 ° C.
Preferably, the reaction temperature is raised to 25% after the phenol content is distilled at 95% or more of the theoretical distillation amount.
The temperature is preferably set to 0 ° C. or higher.

When the degree of polymerization is further increased by using a horizontal twin-screw self-cleaning reactor in the post-polycondensation step, the prepolymer obtained in the first step may be fed directly in a molten state. Alternatively, the pelletized product may be fed again after being melted again by an extruder or the like.

Here, the horizontal two-axis self-cleaning reaction apparatus used in the present invention has two horizontal rotating shafts rotating in the same direction, and rotates together with the rotating shaft in a direction perpendicular to the horizontal rotating shaft. Having a stirring plate attached to the The phases of the respective stirring plates are shifted from each other, and the resins attached to the stirring plates are stirred without stagnation because they rotate while maintaining a slight gap therebetween, and the surface is renewed (self-cleaning property). The cross-sectional shape of the stirring plate is
Examples include a disk type, a hollow disk type, a convex lens type, a bar type, a window frame type, a pseudo-triangular type, and the like, but are not necessarily limited in the present invention.

The reaction temperature in the post-polycondensation step is as follows:
240 ° C to 350 ° C, preferably 250 ° C to 300 ° C
And the pressure is 10 Torr or less, preferably 2 Torr or less. In addition, the horizontal reactor used in the present invention has a larger internal volume than a screw-type twin-screw extruder, and can control the resin extrusion performance depending on the shape and mounting position of the stirring plate. It is possible to increase the residence time. Typically, the residence time is 1
It is 0 minute to 90 minutes, preferably 15 minutes to 60 minutes. In the subsequent polycondensation step, the aromatic polycarbonate obtained after the reaction using a horizontal reaction apparatus has a viscosity average molecular weight of 15,
000-60,000.

In the reactor, the material of the portion in contact with the reaction mixture is a metal or alloy having an iron content of 25% by weight or more, or a nickel and / or copper content of 70% by weight or more. Some are used. The aromatic polycarbonate resin obtained in the present invention can be added with a known heat stabilizer as needed to improve its heat stability. Examples of such heat stabilizers include phosphorus-based heat stabilizers such as phosphite triester, benzenephosphonic acid, and acid phosphate, and antioxidants such as hindered phenol.

The aromatic polycarbonate resin obtained in the present invention may be modified with other resins, if necessary, fillers such as glass fibers and carbon fibers, flame retardants, UV absorbers, and the like. A release agent or a coloring agent may be added. The polycarbonate resin produced by the method of the present invention can produce a high quality aromatic polycarbonate resin having excellent color tone without any problem due to residual methylene chloride. Therefore, the polycarbonate resin can be widely used as a general engineering plastic material such as a sheet or a lens, a use for an optical component such as a compact disc or an optical disc, a use for a transparent component such as an automobile, and a housing for various devices. Is also very advantageous.

[0037]

The present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the present invention. (1) Viscosity average molecular weight (Mv) Intrinsic viscosity [η] (dl) of methylene chloride solution at 20 ° C.
/ g) was measured using an Ubbelohde viscosity tube, and the viscosity average molecular weight was calculated using the following equation.

[0038]

(1) [η] = 1.23 × 10 ⁻⁴ (Mv) ^0.83 (2) Color tone of polymer The color tone of the pellet was measured using a color computer (SM Color Computer, model SM-, manufactured by Suga Test Instruments Co., Ltd.).
The evaluation was made based on the b value measured by the reflection method in 4). The larger the b value, the higher the yellow tint. As a sample having a good color tone, the b value is 1.5 or less, preferably, the b value is 1.
0 or less. (3) Content of benzophenone derivative or benzoate derivative in diphenyl carbonate was measured by high performance liquid chromatography.

(4) Oxygen Concentration An eggplant flask containing 3 g of an aromatic polycarbonate was attached to the column, and the temperature was raised from room temperature to 200 ° C. under aeration with helium. The amount of oxygen in the sample was quantified from the peak area. (5) Hydroxyl Terminal Concentration The terminal OH group was measured using ¹³ C-NMR, and the hydroxyl terminal concentration was calculated as a ratio (%) to the total terminal group concentration. Reference Example (Purification of diphenyl carbonate) 80 kg of diphenyl carbonate was stirred and melted at 100 ° C for 1 hour in a nitrogen stream, and then heated to around 140 ° C. Subsequently, the pressure was reduced to 3 Torr and distillation purification was performed.

At this time, by changing the distillation temperature at 3 Torr, the removal amounts of 2,2′-dihydroxybenzophenone and 2-hydroxybenzoic acid phenyl ester (phenyl salicylate) were respectively adjusted, and the content of each component was adjusted. The amount of diphenyl carbonate shown in the examples and comparative examples was obtained. For example, when the distillation temperature was set to 140 ° C., purified diphenyl carbonate having a content of 2,2′-dihydroxybenzophenone and 2-hydroxybenzoic acid phenyl ester of 10 ppm was obtained in a yield of 94%. .

Example 1 4566 g (20.0 mol) of bisphenol A, 10 ppm of diphenyl carbonate (2,2'-dihydroxybenzophenone (hereinafter, component A)) and phenyl 2-hydroxybenzoate (phenyl salicylate) (hereinafter, B
Ingredient) contains 10 ppm) 4584 g (21.4 mol)
And 0.022 g of trilithium nitrilotriacetate (monohydrate)
(0.001 mol) in a 30 l tank reactor (SUS31)
6L: Fe67wt%, Cr18wt%, Ni12wt%, Mo3wt
%, C0.03 wt%), and after the atmosphere was replaced with nitrogen, the temperature was gradually increased. Stirring was started after the reaction mixture was dissolved, and this time was defined as the polymerization start time (temperature in the tank: 180 ° C.). Thereafter, the temperature was further raised to 270 ° C., and the pressure was gradually reduced. The generated phenol was distilled off to continue the reaction. At this time, the phenol amount was 97% of the theoretical distillate amount (3.5 l).
(3.4 l) After distilling, the reaction temperature was raised to 250 ° C. or higher. Finally, the inside of the tank was maintained at 1 Torr and 270 ° C., and the polymerization was completed in a total polymerization time of 4 hours. After the inside of the tank was restored, the strand was extruded into a water tank and pelletized by a cutter. The obtained polymer was colorless and transparent, and had a viscosity average molecular weight of 16,700 (having a hydroxyl terminal concentration of 9.0%). The color tone was 0.10 in b value, and the content of the A component and the B component in this polymer was 15 ppm, respectively.
It was 7 ppm. Oxygen concentration in polymer is 36ppm
Met.

Example 2 Polymerization was carried out in the same manner as in Example 1 except that diphenyl carbonate containing 60 ppm of the component A and 60 ppm of the component B was used. The obtained polymer was colorless and transparent, and had a viscosity average molecular weight of 15,800 (having a hydroxyl terminal concentration of 11.5%). The color tone was 0.30 in b value, and the content of the A component and the B component in this polymer was 80 ppm and 50 ppm, respectively. The oxygen concentration in the polymer was 52 ppm.

Example 3 Polymerization was carried out in the same manner as in Example 1 except that diphenyl carbonate containing 10 ppm of the component A and 80 ppm of the component B was used. The obtained polymer was colorless and transparent, and had a viscosity average molecular weight of 17,000 (having a hydroxyl terminal concentration of 8.8%). The color tone was 0.20 in b value, and the content of the A component and the B component in the polymer was 30 ppm and 60 ppm, respectively. The oxygen concentration in the polymer was 55 ppm.

Example 4 Nickel 200 (Ni 99.5 wt%, C 0.0
Polymerization was carried out in the same manner as in Example 1 except that 5 wt%) was used. The obtained polymer was colorless and transparent, and had a viscosity average molecular weight of 17,000 (having a hydroxyl terminal concentration of 13.9).
%)Met. The color tone was 0.13 in b value, and the content of each of the A component and the B component in the polymer was 1
6 ppm and 5 ppm. The oxygen concentration in the polymer was 46 ppm.

Example 5 To 100 parts by weight of the prepolymer polymerized in Example 1 was added 0.03 parts by weight of diphenyl phosphonate as a heat stabilizer, and the mixture was melted at 270 ° C. with a twin-screw extruder to obtain a horizontal 2 Shaft self-cleaning high-viscosity reactor (2 l internal volume, reaction temperature 270 ° C, vacuum degree 0.2 Torr, rotation speed 60 rpm)
And extracted with a gear pump at 2.5 kg / h. The residence time was 30 minutes. The obtained polymer was colorless and transparent, and had a viscosity average molecular weight of 27,800 (having a hydroxyl terminal concentration of 5.0%). The color tone was 0.32 in b value, and the content of the A component and the B component in this polymer was 23 ppm and 3 ppm, respectively. The oxygen concentration in the polymer was 71 ppm.

Example 6 Polymerization was carried out in the same manner as in Example 1 except that 0.28 g (0.001 mol) of trisodium nitrilotriacetate (monohydrate) was used as a catalyst. The obtained polymer was colorless and transparent, and had a viscosity average molecular weight of 16,300 (having a hydroxyl terminal concentration of 9.2%). The color tone was 0.18 in b value, and the content of the A component and the B component in this polymer was 17 ppm and 6 ppm, respectively. The oxygen concentration in the polymer was 88 ppm.

Comparative Example 1 4566 g (20.0 mol) of bisphenol A, diphenyl carbonate (10 ppm of component A and 10 ppm of component B)
4584 g (21.4 mol), and 0.022 g (0.001 g) of trilithium nitrilotriacetate (monohydrate).
(1 mol) was charged into a 30 l tank reactor (SUS316L), and the temperature was gradually increased after purging with nitrogen. Stirring was started after the reaction mixture was dissolved, and this time was defined as the polymerization start time (temperature in the tank: 180 ° C.). Thereafter, the temperature was further raised to 270 ° C., and the pressure was gradually reduced. The generated phenol was distilled off to continue the reaction. At this time, the reaction temperature was raised to 250 ° C. or higher after 80% (2.8 l) of the phenol amount was distilled out of the theoretical distillation amount (3.5 l). Finally, the inside of the tank was maintained at 1 Torr and 270 ° C., and the polymerization was completed in a total polymerization time of 4 hours. After the inside of the tank was restored, the strand was extruded into a water tank and pelletized by a cutter. The obtained polymer is yellowish and has a viscosity average molecular weight of 15,900.
(The concentration of hydroxyl group terminals was 25.5%). The color tone was 5.20 in b value, and the content of the A component and the B component in this polymer was 140 ppm and 100 pp, respectively.
m. The oxygen concentration in the polymer was 126 ppm.

Comparative Example 2 Polymerization was carried out in the same manner as in Comparative Example 1 except that diphenyl carbonate containing 80 ppm of the component A and 100 ppm of the component B was used. The obtained polymer was yellowish and had a viscosity average molecular weight of 16,700 (having a hydroxyl terminal concentration of 22.4%). In addition, the color tone is 4.
The content of the A component and the B component in the polymer was 120 ppm and 60 ppm, respectively. The oxygen concentration in the polymer was 163 ppm.

[0049]

According to the process for producing an aromatic polycarbonate according to the present invention, there is no problem due to residual methylene chloride.
Since a high-quality aromatic polycarbonate resin having excellent color tone can be produced, it can be used for a wide range of applications.

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Hidekazu Shoji 1000 Kamoshita-cho, Midori-ku, Yokohama-shi, Kanagawa Prefecture Mitsubishi Chemical Research Institute (56) References JP-A-5-125170 (JP, A) 4-72327 (JP, A) JP-A-4-142329 (JP, A) Patent 3296030 (JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08G 64/00-64/42

Claims (9)

(57) [Claims] 1. An aromatic polycarbonate wherein each of a benzophenone derivative and an ester derivative is 100 ppm or less. 2. An aromatic polycarbonate having a benzophenone derivative and an ester derivative having a molecular weight of less than 1,000, each of which is 100 ppm or less. 3. The aromatic polycarbonate according to claim 1, which is produced by a transesterification reaction between an aromatic dihydroxy compound and a diaryl carbonate. 4. The aromatic polycarbonate according to claim 1, which is produced by transesterification of an aromatic dihydroxy compound and a diaryl carbonate with an iminocarboxylic acid derivative or a salt thereof as a catalyst. 5. The aromatic polycarbonate according to claim 1, wherein the benzophenone derivative is mono- or dihydroxybenzophenone. 6. The aromatic polycarbonate according to claim 5, wherein the benzophenone derivative is 2,2'-dihydroxybenzophenone. 7. An aromatic polycarbonate according to claim 1, wherein the ester derivative is phenyl hydroxybenzoate. 8. The aromatic polycarbonate according to claim 1, which has an oxygen concentration of 100 ppm or less. 9. The aromatic polycarbonate according to claim 1, wherein the viscosity average molecular weight is 10,000 or more and the hydroxyl terminal is 20% or less among the terminals of the polycarbonate.