JPH07238158A - Aromatic polycarbonate and its production - Google Patents

Abstract

PURPOSE:To obtain a high-quality aromatic polycarbonate excellent in hue without any problem caused by residual methylene chloride. CONSTITUTION:This aromatic polycarbonate is desirably prepared by the transesterification reaction of an aromatic dihydroxy compound with a diaryl carbonate and has a total content of products of decomposition, decomposition/ condensation and rearrangement of the aromatic dihydroxy compound of 100ppm or below and a viscosity-average molecular weight of 10000 or above.

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 engineering plastic and a method for producing the same. More particularly, it relates to a high quality aromatic polycarbonate having an excellent color tone and a method for producing the same.

[0002]

2. Description of the Related Art Aromatic polycarbonates are widely used as engineering plastics for applications that make use of their excellent impact resistance, dimensional stability and transparency. As an industrial production method, an interfacial method of reacting an aromatic dihydroxy compound such as bisphenol with phosgene, or a transesterification method of reacting an aromatic dihydroxy compound such as bisphenol with a carbonic acid diaryl ester such as diphenyl carbonate in a molten state ( Melting method)
It has been known.

Generally, when an aromatic polycarbonate is produced by a transesterification method, an aromatic dihydroxy compound and a carbonic acid diaryl ester, which are raw materials, are treated with a metal organic acid salt, inorganic acid salt, oxide, hydroxide, With a catalyst such as hydride or alcoholate, 240-33
The transesterification reaction is carried out in the molten state while heating under reduced pressure at a temperature of 0 ° C. Therefore, as compared with the above-mentioned interfacial method, since no solvent is used, there is an advantage that the aromatic polycarbonate can be produced at low cost.

[0004]

However, in the transesterification method, since the aromatic dihydroxy compound and the carbonic acid diaryl ester are reacted in a molten state, the resulting polycarbonate is exposed to a high temperature for a long time, resulting in a yellow color. There was a big problem of coloring. For example, Japanese Patent Application Laid-Open No. 63-2101126 describes that it is important not to include impurities that cause discoloration of the resin and a decrease in the molecular weight when the polycarbonate is subjected to a high temperature treatment (280 to 350 ° C.). Also, "polycarbonate resin", Nikkan Kogyo Shimbun, 1969, 14
It is described on page 5 that the thermal decomposition of polycarbonate is promoted by the presence of impurities and unreacted bisphenol A. However, these methods have not been able to sufficiently improve the color tone of polycarbonate.

[0005]

Means for Solving the Problems As a result of intensive studies to develop a high-quality aromatic polycarbonate having an excellent color tone, the present inventors have found that decomposition products, decomposition condensation products and rearranged products of aromatic polycarbonate are 100 ppm or less. Therefore, the present invention has been accomplished by finding out that the above problems can be solved by using an aromatic polycarbonate resin having a viscosity average molecular weight of 10,000 or more, and finding out a method thereof.

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

[0007]

[Chemical 1]

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 aryl group which may be substituted, and X is

[0009]

[Chemical 2]

(However, R ³ and R ⁴ are each independently a hydrogen atom,
Represents an alkyl group having 1 to 12 carbon atoms or an aryl group having 6 to 12 carbon atoms),

[0011]

[Chemical 3]

(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 and 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 , Bis (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'-dihydroxydiphenyl ether, 4,4'-dihydroxydiphenyl sulfide, 4,4'-dihydroxydiphenyl sulfoxide, 4,4'-dihydroxydiphenyl sulfone , Phenolphthalein and the like. These aromatic dihydroxy compounds may be used alone or as a mixture. Of these, preferably
It is 2,2-bis (4-hydroxyphenyl) propane.

The total amount of decomposed products, decomposed condensates and rearranged products of the aromatic dihydroxy compound in the aromatic polycarbonate of the present invention is 100 ppm or less, preferably 50 ppm or less, more preferably 30 ppm or less, particularly preferably 20 ppm or less. If the total amount of decomposed products, decomposed condensates and rearranged products of the aromatic dihydroxy compound is more than 100 ppm, the aromatic polycarbonate is colored yellow.

The decomposed product, decomposed condensate and rearranged product of the aromatic dihydroxy compound of the present invention are generally compounds produced by decomposition, decomposed condensation or rearrangement of an aromatic dihydroxy compound due to thermal history during the production of aromatic polycarbonate. And examples thereof include bisphenols, trisphenols, chromanes, indanes and the like. As a specific example, 2- (3-hydroxyphenyl) -2- (4
-Hydroxyphenyl) propane, 2- (3-hydroxyphenyl) -2- (4-hydroxyphenyl) propane, 2,2-bis (3-hydroxyphenyl) propane, 2- (2-hydroxyphenyl) -2- ( 3-hydroxyphenyl) propane, 2,2-bis (2-hydroxyphenyl) propane, 2,2-bis (4-hydroxyphenyl) ethane, 2- (3-methyl-4-hydroxyphenyl) -2- (4 -Hydroxyphenyl) propane, 2- (2-methyl-4-hydroxyphenyl) -2
-(4-hydroxyphenyl) propane, 2- (2-methyl-4-hydroxyphenyl) -2- (3-methyl-
4-hydroxyphenyl) propane, 2,2-bis (2
-Methyl-4-hydroxyphenyl) propane, 2,2
-Bis (3-methyl-4-hydroxyphenyl) propane, 2,4-bis (2- (4-hydroxyphenyl) propyl) phenol (hereinafter, compound 1), 2- (2-
(4-Hydroxyphenyl)) propyl) -2- (4-
Hydroxyphenyl) propane, 1,3-bis (4-hydroxyphenyl) -2,3-dimethyl-1-butene (: compound 2), 2,4-bis (4-hydroxyphenyl) -4-methyl-1- Butene (: Compound 3), 2,
2-bis (4-hydroxyphenyl) -1-phenoxypropane (: compound 4), 2,4-bis (4-hydroxyphenyl) -4-methyl-1-phenoxypentane (: compound 5), 4-hydroxyphenyl -2- (4
-Hydroxyphenyl) propyl-5-phenoxy-1
-Pentene (: Compound 6), 1,1,3-trimethyl-
3- (4-hydroxyphenyl) -4-hydroxyindane (: compound 7), 1,1,3-trimethyl-3-
(4-Hydroxyphenyl) -5-hydroxyindane (: compound 8), 1,1,3-trimethyl-3- (4-
Hydroxyphenyl) -6-hydroxyindane (: compound 9), 1,1,3-trimethyl-3- (4-hydroxyphenyl) -7-hydroxyindane (: compound 1)
0), 2,2,4-trimethyl-4- (4-hydroxyphenyl) chroman (: compound 11), 2,4,4-trimethyl-2- (4-hydroxyphenyl) chroman (: compound 12), 2 , 2,4-trimethyl-4-
(4-hydroxyphenyl) -6- (2- (4-hydroxyphenyl) propyl) chroman (: compound 13) and the like.

Of these, 1,3-bis (4-hydroxyphenyl) -2,3-dimethyl-1-butene (:
Compound 2), 2,4-bis (4-hydroxyphenyl)
-4-Methyl-1-butene (: Compound 3), 2,2-bis (4-hydroxyphenyl) -1-phenoxypropane (: Compound 4), 1,1,3-trimethyl-3- (4
-Hydroxyphenyl) -5-hydroxyindane (:
It is highly effective to improve the color tone by suppressing the content of compound 8) and 2,2,4-trimethyl-4- (4-hydroxyphenyl) chroman (: compound 11).

The chemical structural formulas of compounds 1 to 13 are shown below.

[0017]

[Chemical 4]

Next, the carbonic acid diaryl ester used in the present invention includes diphenyl carbonate and bis (p
-Chlorophenyl) carbonate, bis (o-chlorophenyl) carbonate, bis (2.4-dichlorophenyl) carbonate, bis (p-nitrophenyl) carbonate, bis (o-nitrophenyl) carbonate, bisallyl carbonate of bisphenol A, phenyl carbonate at the end Examples thereof include a polycarbonate oligomer having a group. Diphenyl carbonate is preferred. Usually, these carbonic acid 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 aromatic polycarbonate of the present invention 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, there is a tendency for adverse effects such as deterioration of color tone when left in the air for a long time or during molding. If necessary, a mono-substituted phenol as a terminal blocking group may be added to the aromatic polycarbonate shown in the present invention. The monofunctional phenols used for such purposes include those represented by the general formula (II)

[0020]

[Chemical 5]

There is a compound represented by: Specific examples include cresol, methoxyphenol, tert-butylphenol, amylphenol, hexylphenol, octylphenol, cumylphenol and phenylphenol. 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 method for producing an aromatic polycarbonate of the present invention, phloroglucin and 1,1,1-tris (4
It is also possible to prepare a branched polycarbonate by adding a trifunctional or higher polyfunctional compound such as -hydroxyphenyl) -ethane. Furthermore, terephthalic acid or dicarboxylic acid such as isophthalic acid may be added to obtain an aromatic polyester polycarbonate.

The transesterification catalyst used in the present invention is
Specifically, tetramethylammonium-tetraphenylboranate, ammonium such as tetraphenylphosphonium-tetraphenylboranate, tetramethylammonium hydroxide, tetrabutylammonium hydroxide, ammonium hydroxide such as trimethylbenzylammonium hydroxide, dimethyl. Quaternary ammonium salts such as phenylbenzylammonium chloride and benzyltributylammonium chloride, triethylamine, 2-methylimidazole, dimethyl-
Amines such as 4-aminopyridine or salts thereof, nitrogen-containing basic compounds such as iminocarboxylic acid derivatives or salts thereof, alkali metal or alkaline earth metal phenolates, carbonates, acetates, hydroxides, hydrides, etc. Other examples include phosphorus compounds such as phenylphosphoric acid, phenylphosphorous acid and metal salts thereof, and phosphonium borane salt catalysts. Among them, iminocarboxylic acid derivatives or salts thereof,
Alternatively, ammonium such as tetramethylammonium-tetraphenylboranate and tetraphenylphosphonium-tetraphenylboranate, ammonium hydroxide such as tetramethylammonium hydroxide, tetrabutylammonium hydroxide and trimethylbenzylammonium hydroxide, dimethylphenylbenzylammonium chloride. , Nitrogen-containing basic compounds such as quaternary ammonium salts such as benzyltributylammonium chloride, and iminocarboxylic acid derivatives or salts thereof are particularly preferable. These may be used alone or in combination with the other catalysts mentioned above.

The iminocarboxylic acid derivative is a compound having a group represented by the general formula (III) in the molecule.

[0025]

[Chemical 6]

(In the formula, n represents an integer of 1-3.) 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, cyclohexane Diaminetetraacetic acid, xylylenediaminetetraacetic acid, diaminetetracarboxylic acid type compounds such as glycol ether diaminetetraacetic acid, diethylenetriaminepentaacetic acid, trimethylenetetraminehexaacetic acid, and the like, among which nitrilotriacetic acid, nitrilotripropionic acid Such nitrilotricarboxylic acid type compounds are preferable, and nitrilotriacetic acid is particularly preferable.

As the metal salt of the iminocarboxylic acid derivative, various metal salts of the above iminocarboxylic acid derivative can be used. For example, alkali metals such as lithium, sodium and potassium, beryllium, magnesium, calcium and barium can be used. Alkaline earth metals, zinc, such as
Examples thereof include metal salts such as cadmium, copper, tin, lead, manganese, cobalt and nickel. Among them, alkali metals such as lithium, sodium and potassium are preferable, and lithium and sodium are particularly preferable.

The amount of the iminocarboxylic acid derivative or metal salt thereof used is about 1 × 10 ^-9 to 1 mol%, preferably 1 × 10 ^-8 , based on the total amount of the aromatic dihydroxy compound used as a raw material. It is about 1 × 10 ^-2 mol%. When the amount of the catalyst is too small, the polymerization rate becomes slow, which causes coloring. Further, even if it is used in an excessively large amount, it becomes a factor which adversely affects coloring, thermal stability, hydrolysis resistance and the like.

Further, in order to further increase the polymerization activity in addition to the above transesterification catalyst, N, N, N ', N'-tetramethylethylenediamine, N, N, N', N'-tetramethyl-1,4 -Diaminobutane, N, N, N ', N'-tetramethylhexamethylenediamine, N, N, N',
N ", N" -pentamethyldiethylenetriamine, N,
N, N ', N ", N'", N '"-hexamethyltriethylenetetramine, triethylenediamine, hexamethylenetetramine, N, N', N", N "'-tetramethyl-
A polyamine compound such as 1,4,8,11-tetraazacyclotetradecane may be used as a cocatalyst.

In the method for producing an aromatic polycarbonate of the present invention, it is possible to produce a polycarbonate resin in a single step using a tank reactor, but especially when producing a high molecular weight polycarbonate resin, It is preferable to synthesize a prepolymer having a low melt viscosity in the condensation step using a tank-type reactor and to make the prepolymer have a high molecular weight in the post-polycondensation step. In the post-polycondensation step, a production method with a small heat history is preferable, and examples of such a production method include a method using a high-viscosity reactor and a solid-phase polymerization method. Among them, a method using a high-viscosity reactor is preferable, and a method using a horizontal biaxial self-cleaning high-viscosity reactor is particularly preferable.

The reaction temperature in the prepolycondensation step is usually 1
The temperature is in the range of 40 ° C. to 320 ° C., and the pressure is in the range of 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. When the molecular weight of the prepolymer exceeds 20,000, it is necessary to carry out at a high temperature of 330 ° C. or higher in order to prevent the melt viscosity from increasing during the production in the tank reactor, which is disadvantageous in terms of color tone. Become.

Further, in order to suppress the formation of decomposed products, decomposed condensates and rearranged products of the aromatic dihydroxy compound which adversely affects the color tone, the aromatic dihydroxy compound is in a state of 3 × 10 ⁴ ppm or less in the reaction solution. Then, the reaction temperature is preferably 240 ° C. or higher. That is, the raw material aromatic dihydroxy compound is sufficiently transesterified at a low reaction temperature such that the aromatic dihydroxy compound is not decomposed, decomposed and condensed, and rearranged, and the amount of the aromatic dihydroxy compound is kept at 240 ° C. or higher in a state as small as possible. Preferably. More preferably, the aromatic dihydroxy compound is 1 × 10 ⁴ ppm or less in the reaction solution, more preferably 5 × 10 ³ ppm or less, particularly preferably 3 × 1.
That is, the reaction temperature is set to 240 ° C. or higher in the state of 0 ³ ppm or lower. In addition, the charging ratio of the aromatic dihydroxy compound and the carbonic acid diaryl ester is appropriately set according to the catalyst, and the temperature, the degree of reduced pressure, and the like are appropriately set to allow the reaction between the aromatic dihydroxy compound and the carbonic acid diaryl ester. The amount of unreacted aromatic dihydroxy compound can be controlled to a small amount by advancing as much as possible at less than 240 ° C.

In the post-polycondensation step, the polymerization degree is further increased by using a high-viscosity reactor such as a horizontal biaxial self-cleaning reactor. At this time, the prepolymer obtained in the first step may be directly fed in the molten state, or the pelletized product may be fed again after being melted by an extruder or the like. Here, the horizontal type two-axis self-cleaning reaction device used in the present invention is, for example, two horizontal rotary shafts that rotate in the same direction and two horizontal rotary shafts attached to the horizontal rotary shaft so as to rotate together with the rotary shaft in the vertical direction. It has a stirring plate. Since the phases of the stirring plates are out of phase and rotate while keeping a slight gap between them, the resin attached to the stirring plates is stirred without staying and the surface is updated (self-cleaning property). Examples of the cross-sectional shape of the stirring plate include a disc type, a hollow disc type, a convex lens type, a rod type, a window frame type, and a pseudo triangle type, but the present invention is not necessarily limited thereto.

The reaction temperature in the post-polycondensation step is 2
The temperature is 40 ° C to 350 ° C, preferably 250 ° C to 300 ° C, and the pressure is 10 Torr or less, preferably 2 Torr or less. Further, the horizontal reactor used in the present invention has a large internal volume of the apparatus as compared with a screw type twin-screw extruder, and the resin extrusion performance can be controlled by the shape and mounting position of the stirring plate. It is possible to take a long residence time. Usually the residence time is 5 minutes to 120 minutes, preferably 15 minutes to 90 minutes. The viscosity average molecular weight of the aromatic polycarbonate obtained after the reaction using a horizontal reactor in the subsequent polycondensation step is 10,0.
00 or more, preferably 10,000 to 60,000, and more preferably 13,000 to 40,000.

Of the terminals of the aromatic polycarbonate, the terminal hydroxyl groups are preferably 20% or less, more preferably 10% or less. When the hydroxyl group end exceeds 20%, heat resistance and hydrolysis resistance are adversely affected. Also,
The aromatic polycarbonate obtained in the present invention may 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 triesters, benzenephosphonic acid, and acidic phosphoric acid esters, and antioxidants such as hindered phenols.

The aromatic polycarbonate obtained in the present invention may be modified with other resins, if necessary, or may be a filler such as glass fiber or carbon fiber, a flame retardant, and U.
You may add V absorber, a mold release agent, and a coloring agent.

[0037]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. (1) Viscosity average molecular weight (Mv) Intrinsic viscosity [η] (dl
/ g) was measured using an Ubbelohde viscosity tube, and the viscosity average molecular weight was calculated using the following formula.

[0038]

[Equation 1] [η] = 1.23 × 10 ⁻⁴ (Mv) ^0.83 (2) Color tone of polymer The color tone of the pellets is a color computer (SM color computer manufactured by Suga Test Instruments Co., Ltd., model SM-).
Evaluation was made by the b value measured by the reflection method in 4). The larger the b value is, the higher the yellowness is, and as a sample having a good color tone, the b value is 1.5 or less, preferably the b value is 1.0.
It is the following. (3) Content of bisphenol A in the reaction solution The reaction solution was taken out and rapidly cooled with liquefied nitrogen to obtain a coagulated product. The coagulated product was quantified by a gel permeation chromatography (GPC) method using a calibration curve of bisphenol A.

(4) Total content of decomposed products, decomposed condensates and rearranged products of bisphenol A in the polymer 10 g of the polymer was dissolved in 50 ml of methylene chloride, and 200 ml of acetone was added dropwise while stirring. After filtration, 50 ml of acetone was added to the precipitate for extraction, and the obtained extract and the above filtrate were combined and concentrated to obtain a concentrate.
Next, the concentrate is subjected to high performance liquid chromatography (HP
It was quantified by the LC) method using a calibration curve of the decomposed product, decomposed condensate and rearranged product of bisphenol A.

Decomposition products, decomposition condensation products and rearrangement products of bisphenol A include 1,3-bis (4-hydroxyphenyl) -2,3-dimethyl-1-butene (: compound 2) and 2,4-bis. (4-hydroxyphenyl) -4-
Methyl-1-butene (: compound 3), 2,2-bis (4
-Hydroxyphenyl) -1-phenoxypropane (:
Compound 4), 1,1,3-trimethyl-3- (4-hydroxyphenyl) -5-hydroxyindane (: Compound 8), 2,2,4-trimethyl-4- (4-hydroxyphenyl) chroman (: Compound 11) was used for quantification. (5) Hydroxyl terminal concentration The OH group at the terminal was measured using ¹³ C-NMR, and the hydroxyl terminal concentration was calculated as a ratio (%) to the total terminal group concentration.

Example 1 Bisphenol A 4566 g (20.0 mol), diphenyl carbonate 4584 g (21.4 mol) and trilithium nitrilotriacetate (monohydrate) 0.022 g (0.0
01 mol) in a 30 liter tank type reactor (SUS316
It was charged in L), the atmosphere was replaced with nitrogen, and then the temperature was gradually raised. After the reaction mixture was dissolved, stirring was started, and the time point was defined as the polymerization start time (internal temperature of 180 ° C.). The temperature inside the tank was raised to 210 ° C., and the pressure was gradually reduced and maintained at 200 Torr for 30 minutes. Thereafter, the temperature was further raised to 270 ° C., and the pressure was gradually reduced to distill off the produced phenol to continue the reaction. (Bisphenol A at a tank temperature of 240 ° C
The concentration was 2,700 ppm. ) Finally, keep the inside of the tank at 1 Torr and 270 ℃, total polymerization time 4
Polymerization was completed in a certain period of time, and after the pressure in the tank was restored, it was extruded in the form of a strand into the water tank to form pellets with a cutter. The obtained polymer is colorless and transparent, and has a viscosity average molecular weight of 15,
It was 700 (the hydroxyl group terminal concentration was 9.0%). Also,
The color tone was 0.20 in b value, and the total content of decomposed products, decomposed condensates and rearranged products of bisphenol A in this polymer was 30 ppm.

Example 2 Bisphenol A 4566 g (20.0 mol), diphenyl carbonate 4584 g (21.4 mol) and trilithium nitrilotriacetate (monohydrate) 0.022 g (0.0
01 mol) in a 30 liter tank type reactor (SUS316
It was charged in L), the atmosphere was replaced with nitrogen, and then the temperature was gradually raised. After the reaction mixture was dissolved, stirring was started, and the time point was defined as the polymerization start time (internal temperature of 180 ° C.). The temperature inside the tank was raised to 220 ° C., and the pressure was gradually reduced and maintained at 200 Torr for 30 minutes. Thereafter, the temperature was further raised to 270 ° C., and the pressure was gradually reduced to distill off the produced phenol to continue the reaction. (Bisphenol A at a tank temperature of 240 ° C
The concentration was 2,400 ppm. ) Finally, keep the inside of the tank at 1 Torr and 270 ℃, total polymerization time 4
Polymerization was completed in a certain period of time, and after the pressure in the tank was restored, it was extruded in the form of a strand into the water tank and pelletized by a cutter. The obtained polymer is colorless and transparent, and has a viscosity average molecular weight of 15,
It was 100 (the concentration of hydroxyl groups at the end was 10.2%). The color tone was 0.32 in terms of b value, and the total content of decomposed products, decomposed condensates and rearranged products of bisphenol A in this polymer was 80 ppm.

Example 3 To 100 parts by weight of the prepolymer polymerized in Example 1 was added 0.03 parts by weight of diphenylphosphonate as a heat stabilizer, and the mixture was melted in a twin screw extruder at 270 ° C. Shaft self-cleaning high-viscosity reactor (internal volume 2 liters, reaction temperature 270 ° C, vacuum degree 0.2 Torr, rotation speed 60)
rpm) and extracted with a gear pump at 1.4 kg / h. The residence time was 40 minutes. The obtained polymer is colorless and transparent, and has a viscosity average molecular weight of 28,800.
(The hydroxyl group terminal concentration was 5.0%). Further, the color tone was 0.27 in b value, and the total content of decomposed products, decomposed condensates and rearranged products of bisphenol A in this polymer was 3
It was 5 ppm.

Example 4 Polymerization was carried out in the same manner as in Example 3 except that the prepolymer polymerized in Example 2 was used. The obtained polymer was colorless and transparent, and the viscosity average molecular weight was 27,900 (hydroxyl group terminal concentration was 6.2%). Further, the color tone was 0.37 in b value, and the total content of decomposed products, decomposed condensates and rearranged products of bisphenol A in this polymer was 88 pp.
It was m.

Example 5 Bisphenol A 4566 g (20.0 mol), diphenyl carbonate 5998 g (28.0 mol) and trilithium nitrilotriacetate (monohydrate) 0.022 g (0.0
01 mol) in a 30 liter tank type reactor (SUS316
It was charged in L), the atmosphere was replaced with nitrogen, and then the temperature was gradually raised. After the reaction mixture was dissolved, stirring was started, and the time point was defined as the polymerization start time (internal temperature of 180 ° C.). The temperature inside the tank was raised to 220 ° C., and the pressure was gradually reduced and maintained at 200 Torr for 30 minutes. At 220 ° C., 1415 g (6.2 mol) of bisphenol A was added so that the molar ratio of diphenyl carbonate to bisphenol A was 1.07. Thereafter, the temperature was further raised to 270 ° C., and the pressure was gradually reduced to distill off the produced phenol to continue the reaction.
(The concentration of bisphenol A at the tank temperature of 240 ° C is 2,
It was 000 ppm. ) Finally, keep the inside of the tank at 1 Torr and 270 ℃, total polymerization time 4
Polymerization was completed in a certain period of time, and after the pressure in the tank was restored, it was extruded in the form of a strand into the water tank to form pellets with a cutter. The obtained polymer is colorless and transparent, and has a viscosity average molecular weight of 16,
It was 500 (the hydroxyl group terminal concentration was 9.6%). Also,
The color tone was 0.14 in b value, and the total content of decomposed products, decomposed condensates and rearranged products of bisphenol A in this polymer was 20 ppm.

Comparative Example 1 4566 g (20.0 mol) of bisphenol A, 4584 g (21.4 mol) of diphenyl carbonate and 0.022 g (0.03 g) of trilithium nitrilotriacetate (monohydrate).
01 mol) in a 30 liter tank type reactor (SUS316
It was charged in L), the atmosphere was replaced with nitrogen, and then the temperature was gradually raised. After the reaction mixture was dissolved, stirring was started, and the time point was defined as the polymerization start time (internal temperature of 180 ° C.). The temperature inside the tank was raised to 240 ° C., and the pressure was gradually reduced and maintained at 240 Torr for 30 minutes. (The concentration of bisphenol A was 40,000 ppm at the temperature of the inside of the tank of 240 ° C.) Thereafter, the temperature was further increased to 270 ° C, the pressure was gradually reduced, and the produced phenol was distilled off to continue the reaction. After that, while continuing to raise the temperature to 270 ° C,
The pressure was gradually reduced, the produced phenol was distilled off, and the reaction was continued. Finally, the inside of the tank was kept at 1 Torr and 270 ° C., the polymerization was completed in a total polymerization time of 4 hours, and after the pressure inside the tank was restored, it was extruded into strands into the water tank to form pellets with a cutter.
The obtained polymer was yellowish and had a viscosity average molecular weight of 14,900 (hydroxyl group terminal concentration was 25.5%). The color tone was 2.20 in b value, and the total content of decomposed products, decomposed condensates and rearranged products of bisphenol A in this polymer was 160 ppm.

Comparative Example 2 4566 g (20.0 mol) of bisphenol A, 4584 g (21.4 mol) of diphenyl carbonate and trilithium nitrilotriacetate (monohydrate) 0.022 g (0.0
01 mol) in a 30 liter tank type reactor (SUS316
It was charged in L), the atmosphere was replaced with nitrogen, and then the temperature was gradually raised. After the reaction mixture was dissolved, stirring was started, and the time point was defined as the polymerization start time (internal temperature of 180 ° C.). The temperature inside the tank was raised to 250 ° C., and the pressure was gradually reduced and maintained at 200 Torr for 30 minutes. (The concentration of bisphenol A at the time when the tank temperature was 240 ° C. was 45,000 ppm.) Thereafter, the temperature was further raised to 270 ° C., the pressure was gradually reduced, and the produced phenol was distilled off to continue the reaction. After that, while continuing to raise the temperature to 270 ° C,
The pressure was gradually reduced, the produced phenol was distilled off, and the reaction was continued. Finally, the inside of the tank was kept at 1 Torr and 270 ° C., the polymerization was completed in a total polymerization time of 4 hours, and after the pressure inside the tank was restored, it was extruded into strands into the water tank to form pellets with a cutter.
The obtained polymer was yellowish and had a viscosity average molecular weight of 14,900 (hydroxyl group terminal concentration was 25.5%). The color tone was 4.70 in b value, and the total content of decomposed products, decomposed condensates and rearranged products of bisphenol A in this polymer was 560 ppm.

Comparative Example 3 The amount of diphenyl carbonate charged was 4263 g (1
(9.9 mol), except that the same procedure as in Example 1 was carried out.
(However, the concentration of bisphenol A at a tank temperature of 240 ° C. was 150,000 ppm.) The obtained polymer was yellowish and had a viscosity average molecular weight of 12,400 (the hydroxyl group terminal concentration was 81.7). %)Met. Further, the color tone was 5.30 in b value, and the total content of decomposed products, decomposed condensates and rearranged products of bisphenol A in this polymer was 720 ppm.

[0049]

INDUSTRIAL APPLICABILITY The aromatic polycarbonate of the present invention has no problem due to residual methylene chloride, has an excellent color tone, and can be used in a wide range of applications. Further, the polycarbonate produced by the method of the present invention can produce a high-quality aromatic polycarbonate resin having an 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, an optical component such as a compact disc or an optical disc, a transparent component such as an automobile, a housing for various devices,
It is also extremely advantageous industrially.

Claims (8)

[Claims] 1. The total amount of decomposed products, decomposed condensates and rearranged products of an aromatic dihydroxy compound is 100 ppm or less,
An aromatic polycarbonate having a viscosity average molecular weight of 10,000 or more. 2. The aromatic polycarbonate according to claim 1, wherein hydroxyl groups have 20% or less of the terminals of the polycarbonate. 3. The aromatic polycarbonate according to claim 1 or 2, which is produced from an aromatic dihydroxy compound and a carbonic acid diaryl ester by a transesterification reaction. 4. When the aromatic polycarbonate resin according to claim 1 or 2 is produced by transesterification of an aromatic dihydroxy compound and a carbonic acid diaryl ester, the aromatic dihydroxy compound is added in an amount of 3 × 10 5 in a reaction solution. ^The reaction temperature is adjusted to 24
A process for producing an aromatic polycarbonate, which comprises carrying out a transesterification reaction at 0 ° C or higher. 5. The method for producing an aromatic polycarbonate according to claim 4, wherein the transesterification reaction is carried out by using a nitrogen-containing basic compound as the transesterification reaction catalyst. 6. The method for producing an aromatic polycarbonate according to claim 5, wherein the nitrogen-containing basic compound is an iminocarboxylic acid derivative or a salt thereof. 7. In producing an aromatic polycarbonate resin, a prepolymer having a viscosity average molecular weight of 5,000 to 20,000 is produced in a pre-polycondensation step using a tank reactor, and then in a post-polycondensation step. 7. The method for producing an aromatic polycarbonate according to claim 4, wherein the molecular weight is increased by a high-viscosity reactor or solid-state polymerization. 8. The method for producing an aromatic polycarbonate according to claim 7, wherein a horizontal biaxial self-cleaning type high viscosity reactor is used in the post-polycondensation step.