JP3352838B2 - Method for producing aromatic polycarbonate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing polycarbonate. More specifically, polymerization reaction rate, hue,
The present invention relates to a method for producing an aromatic polycarbonate having excellent heat resistance and the like.

[0002]

2. Description of the Related Art Polycarbonate is widely used because it has excellent mechanical properties such as impact resistance, and also has excellent heat resistance and transparency. As a method for producing such a polycarbonate, a method of directly reacting an aromatic dihydroxy compound such as bisphenol with phosgene (interface method), or a method in which an aromatic dihydroxy compound such as bisphenol and a diaryl carbonate such as diphenyl carbonate are melted. A method of transesterification (melting method) and the like are known.

Among such production methods, a method for producing a polycarbonate by a transesterification reaction between an aromatic dihydroxy compound and a diaryl carbonate will be described. This method uses a metal organic acid salt, an inorganic acid salt, or a catalyst as a catalyst. A method in which an aromatic dihydroxy compound and a diaryl carbonate are subjected to transesterification while being melted by heating, for example, finally to 250 to 330 ° C. under reduced pressure using an oxide, a hydroxide, a hydride or an alcoholate. is there.

This method has the advantage that polycarbonate can be produced at a lower cost than the above-mentioned interface method, but has the problem that the hue is unfavorable because the polymer is exposed to high temperatures for a long time. Was. Various catalysts have been proposed to improve such a hue, but are inferior to polycarbonates polymerized by the interface method and are not yet sufficient.

In the melt polymerization method, the reaction is carried out at high temperature and reduced pressure in the presence of a catalyst, so that the polymer is liable to be colored. A catalyst system in which a tetraalkylammonium hydroxy is combined with an alkali metal or an alkaline earth metal has been proposed. However, when an alkali metal compound is used, a component insoluble in a solvent such as methylene chloride, which is considered to have a branched structure, may be formed in the polymer depending on the reaction conditions. The generation of insolubles due to the branched structure becomes more pronounced as the degree of polymerization increases.

In some cases, the degree of polymerization of the obtained polycarbonate is greatly reduced during molding. Furthermore, since the resin is exposed to a high-temperature atmosphere, there are problems such as coloring, insolubilization, generation of foreign substances, and reduction in molecular weight due to oxidation reaction, other decomposition reactions, and side reactions.

[0007]

Accordingly, the present invention provides
It is an object of the present invention to provide a method for producing an aromatic polycarbonate which is free of coloring by a melt polymerization method, and which causes less coloring of a resin and generation of foreign matter during molding of the obtained polycarbonate.

[0008]

DISCLOSURE OF THE INVENTION The present invention is based on the finding that by conducting polymerization in the presence of a specific catalyst system, it is possible to produce a high molecular weight polycarbonate which is hardly colored and which is soluble in a solvent. Features.

That is, the present invention relates to a method for producing a polycarbonate by melt-polycondensing an aromatic dihydroxy compound and a diaryl carbonate, wherein (A) a nitrogen-containing basic compound, (B) an alkali metal compound and / or an alkaline earth compound. Metal-like compounds and (C) a cyclic aluminum compound represented by the following general formula:

[0010]

Embedded image

[Wherein, R _a , R _b and R _c each independently represent a monovalent hydrocarbon group having 1 to 20 carbon atoms. Wherein the reaction is carried out in the presence of a catalyst comprising an aromatic polycarbonate.

The aromatic dihydroxy compound that can be used in the present invention is not particularly limited, and examples thereof include a compound represented by the following formula (1).

[0013]

Embedded image

In the formula, X is

[0015]

Embedded image

## EQU1 ##

Here, R ₃ and R ₄ are the same or different and are a hydrogen atom, a halogen atom or a hydrocarbon group having 1 to 12 carbon atoms. As the hydrocarbon group, an aliphatic hydrocarbon group having 1 to 12 carbon atoms or an aromatic hydrocarbon group having 6 to 12 carbon atoms is preferable. Examples of such an aliphatic hydrocarbon group include an alkyl group and an alkenyl group, and examples include a methyl group, an ethyl group, and a propyl group. Examples of the aromatic hydrocarbon group include a substituted or unsubstituted phenyl group and a naphthyl group. Examples of the halogen atom include chlorine, bromine and iodine.

R ₅ is a divalent hydrocarbon group having 4 to 20 carbon atoms, such as an aliphatic hydrocarbon group such as an alkylene group and an alkenylene group, such as a butylene group and a pentylene group.

In the formula, R ₁ and R ₂ are the same or different and are a halogen atom or a monovalent hydrocarbon group having 1 to 12 carbon atoms. Examples of the hydrocarbon group include an aliphatic hydrocarbon group having 1 to 12 carbon atoms and an aromatic group having 6 to 12 carbon atoms. Examples of the aliphatic hydrocarbon group include an alkyl group and an alkenyl group, and more specifically, a methyl group, an ethyl group, and a propyl group. Examples of the aromatic group include a substituted or unsubstituted phenyl group and a naphthyl group. Examples of the halogen atom include chlorine, bromine and iodine.

In the formula, m and n are the same or different and represent 0 or an integer of 1 to 4. Specifically, the following compounds can be exemplified. Bis (4-hydroxyphenyl) methane, 1,1-bis (4-hydroxyphenyl)
Ethane, 2,2-bis (4-hydroxyphenyl) propane, 2,2-bis (4-hydroxyphenyl) butane, 2,2-bis (4-hydroxyphenyl) octane, bis (4-hydroxyphenyl) phenylmethane ,
2,2-bis (4-hydroxy-3-methylphenyl)
Propane, 1,1-bis (4-hydroxy-t-butylphenyl) propane, 2,2-bis (4-hydroxy-
Bis (hydroxyaryl) alkanes such as 3-bromophenyl) propane, bis (hydroxyaryl) cyclohexane such as 1,1-bis (4-hydroxyphenyl) cyclopentane and 1,1-bis (4-hydroxyphenyl) cyclohexane Alkanes, 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxy-3,
Dihydroxyaryl ethers such as 3'-dimethylphenyl ether; 4,4'-dihydroxydiphenylsulfide; dihydroxydiarylsulfides such as 4,4'-dihydroxy-3,3'-dimethyldiphenylsulfide;4,4'-dihydroxy Dihydroxydiarylsulfoxides such as diphenylsulfoxide and 4,4'-dihydroxy-3,3'-dimethyldiphenylsulfoxide;4,4'-dihydroxydiphenylsulfone;4,4'-dihydroxy-3,3'-dimethyldiphenylsulfone Dihydroxydiaryl sulfones, 9,9-bis (4-hydroxyphenyl)
And dihydroxydiaryls such as fluorene.

Of these, in particular, 2,2-bis (4-
(Hydroxyphenyl) propane (bisphenol A) is preferably used. These aromatic dihydroxy compounds can be used alone or in combination.

Diaryl carbonate has 6 to 2 carbon atoms.
The carbonate is not particularly limited as long as it has an optionally substituted aryl group of 0, and specifically, diphenyl carbonate, ditolyl carbonate, bis (chlorophenyl) carbonate, m-cresyl carbonate, dinaphthyl carbonate, bis (Diphenyl) carbonate and the like can be mentioned. The above diaryl carbonate is usually used in an amount of 1.0 to 1.30 mol, preferably 1.10 mol, per 1 mol of the aromatic dihydroxy compound.
Preferably, it is used in an amount of from 01 to 1.20 mol.

The catalyst used in the present invention comprises (A) a nitrogen-containing basic compound, (B) an alkali metal compound and / or an alkaline earth metal compound, and (C) a cyclic aluminum compound represented by the following general formula.

[0024]

Embedded image

[Wherein, R _a , R _b and R _c each independently represent a monovalent hydrocarbon group having 1 to 20 carbon atoms. ].

Specific examples of (A) the nitrogen-containing basic compound include tetramethylammonium hydroxide (Me
₄ NOH), tetraethylammonium hydroxide alkyl such (Et ₄ NOH), tetrabutylammonium hydroxide (Bu ₄ NOH), trimethylbenzylammonium hydroxide (phenyl _{-CH 2 (Me) 3 NOH)} , aryl, Aruariru group such as Tertiary amines such as trimethylamine, triethylamine, dimethylbenzylamine, and triphenylamine; R ₂ NH (where R is an alkyl group such as methyl and ethyl; and an aryl group such as phenyl and toluyl). RN), RN
Primary amines represented by H ₂ (where R is the same as above), imidazoles such as 2-methylimidazole and 2-phenylimidazole, and ammonium carboxylate such as tetramethylammonium acetate (Me ₄ NOCOCH ₃ ) Or tetramethylammonium borohydride (Me ₄ NBH ₄ ), tetrabutylammonium tetraphenyl borate (Bu ₄ NBP)
h _4), tetramethylammonium tetraphenylborate (Me ₄ NBPh ₄₎ may be mentioned basic salts such as.

Of these, ammonium hydroxides are preferred, and tetramethylammonium hydroxide (Me ₄ NOH) is particularly preferred. These compounds may be used alone or in combination of two or more.

(B) Alkali metal compounds and alkaline earth metal compounds include hydroxides, bicarbonates,
Carbonates, acetates, borohydrides, stearates, benzoates, salts with bisphenol, and the like.

Specific examples of the alkali metal compound include sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium hydrogen carbonate, potassium hydrogen carbonate, lithium hydrogen carbonate, sodium carbonate, potassium carbonate, lithium carbonate, sodium acetate, Potassium acetate, lithium acetate, sodium stearate, potassium stearate, lithium stearate, sodium benzoate, potassium benzoate, lithium benzoate, disodium hydrogen phosphate, dipotassium hydrogen phosphate, dilithium hydrogen phosphate, bisphenol A Disodium salt, dipotassium salt, dilithium salt, phenol sodium salt, potassium salt, lithium salt and the like.

Specific examples of the alkaline earth metal compound include calcium hydroxide, barium hydroxide, magnesium hydroxide, strontium hydroxide, calcium hydrogen carbonate, barium hydrogen carbonate, magnesium hydrogen carbonate, strontium hydrogen carbonate, Examples include calcium carbonate, barium carbonate, magnesium carbonate, strontium carbonate, calcium acetate, barium acetate, magnesium acetate, strontium acetate, calcium stearate, barium stearate, magnesium stearate, and strontium stearate. These compounds may be used alone or in combination of two or more.

(C) The cyclic aluminum compound has the following general formula

[0032]

Embedded image

Is a compound represented by the formula: Where R _a ,
R _b and R _c each independently represent a monovalent hydrocarbon group having 1 to 20 carbon atoms, a monovalent aliphatic hydrocarbon group having 1 to 12 carbon atoms, or a monovalent alicyclic group having 5 to 12 carbon atoms. Aromatic hydrocarbon groups and aromatic hydrocarbon groups having 6 to 20 carbon atoms are preferred. More preferably, R _a , R _b and R _c are each independently a monovalent aliphatic hydrocarbon group having 1 to 8 carbon atoms, a monovalent alicyclic hydrocarbon group having 5 to 8 carbon atoms, 6-12 aromatic hydrocarbon groups are preferred. Examples of the aliphatic hydrocarbon group include an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group, an octyl group, and a propenyl group, and an alkenyl group.Examples of the alicyclic hydrocarbon group include a cyclopentyl group and a cyclohexyl group. Examples of the group include a cycloalkyl group and the like, and examples of the aromatic group include a phenyl group and a naphthyl group which may be substituted. These compounds may be used alone or in combination of two or more.

Specific examples of the cyclic aluminum compound include the following compounds. In the following formula, Me is a methyl group, Et is an ethyl group, i-Pr is an isopropyl group,
n-Bu represents a normal butyl group, and Ph represents a phenyl group.

[0035]

Embedded image

The amount of these catalysts used is (A) 10 ^-6 to 10 ^-1 mol of nitrogen-containing basic compound, (B) alkali metal compound and / or alkaline earth compound per 1 mol of aromatic dihydroxy compound. Metal compound of 10 ^-8 to 10 ^-4
Mole, (C) 10 ^-9 to 10 ^-3
It is preferred to use it in the molar range. More preferably, (A) 10 ^-5 to 10 ^-3 mol of (A) a nitrogen-containing basic compound and (B) 10 ^-7 to 10 mol of an alkali metal compound and / or an alkaline earth metal compound per 1 mol of an aromatic dihydroxy compound. ^-5 mol The (C) cyclic aluminum compound is preferably used in the range of 10 ^-7 to 10 ^-5 mol.

[0038] When the ratio exceeds this range, coloring or branched components are liable to be formed. When the ratio is below this range, the effect of the catalyst is low, a sufficient reaction rate cannot be obtained, and the physical properties tend to deteriorate.

In the present invention, the method of charging the catalyst may be either solid or liquid, but is preferably a solution or suspension. The concentration of the solution or suspension may be a concentration that can be handled in a liquid state, and is preferably 30% by weight or less, more preferably 20% by weight or less. The concentration of oxygen dissolved in the solution or suspension is preferably 100 ppm or less, more preferably 50 ppm or less, even more preferably 10 ppm or less. If it exceeds this range, coloring or branched components are likely to be generated due to the influence of dissolved oxygen.

In the present invention, it is also preferable to add various stabilizers in a molten state at least one time before, during or after polymerization. Examples of the stabilizer include a sulfur-containing acidic compound and / or a derivative formed from the acidic compound, a phenol-based stabilizer, a thioether-based stabilizer, a phosphorus-based stabilizer, a hindered amine-based stabilizer, an epoxy compound, a salicylic acid-based ultraviolet absorber, Benzotriazole ultraviolet absorbers and the like can be mentioned.

Examples of the sulfur-containing acidic compound and / or the derivative formed from the acidic compound include sulfurous acid, sulfuric acid, sulfinic acid compounds, sulfonic acid compounds, and derivatives thereof. Specifically, as the sulfuric acid derivatives, dimethyl sulfate, diethyl sulfate, sulfuric acid,
Dipropyl sulfate, dibutyl sulfate, diphenyl sulfate, dimethyl sulfite, diethyl sulfite, diphenyl sulfite, sodium dodecyl sulfate, sodium hexadecyl sulfate, dimethyl butyl hexadecyl ammonium butyl sulfate, dimethyl ethyl hexadecyl ammonium ethyl sulfate, trimethyl hexadecyl ammonium methyl sulfate, etc. Can be mentioned.

Examples of the sulfinic acid compound include benzenesulfinic acid, toluenesulfinic acid, naphthalenesulfinic acid and the like. Examples of the sulfonic acid compound and its derivative include the following compounds. That is, benzenesulfonic acid, p
-Sulfonic acids such as toluenesulfonic acid, methylbenzenebenzenesulfonate, ethylbenzenebenzenesulfonate, butylbenzenesulfonate, octylbenzenesulfonate, phenylbenzenesulfonate, methyl p-toluenesulfonate, ethyl p-toluenesulfonate, p- Butyl toluenesulfonate, octyl p-toluenesulfonate, p-
Examples thereof include sulfonic acid esters such as phenyl toluenesulfonic acid, and ammonium sulfonic acid salts such as ammonium p-toluenesulfonate, tetrabutylphosphonium p-toluenesulfonate, and tetraphenylphosphonium dodecylbenzenesulfonate.

These compounds can be used alone or in combination. Of these, [B] pK
As the sulfur-containing acidic compound having an a value of 3 or less and a derivative formed from the acidic compound, a sulfonic acid compound or a derivative thereof is preferably used. In particular, benzenesulfonic acid, butylbenzenesulfonic acid, p-toluenesulfonic acid, Ethyl p-toluenesulfonate, butyl p-toluenesulfonate, sodium dodecyl sulfate, trimethylhexadecyl ammonium methyl sulfate, tetrabutylphosphonium p-toluenesulfonate, and tetraphenylphosphonium dodecylbenzenesulfonate are preferably used.

Examples of the phenolic stabilizer include, for example, n
-Octadecyl-3- (4-hydroxy-3 ', 5'-
Di-tert-butylphenyl) propionate, tetrakis [methylene-3- (3 ′, 5′-di-tert-butyl-4-
Hydroxyphenyl) propionate] methane, 1,
1,3-tris (2-methyl-4-hydroxy-5-t
-Butylphenyl) butane, distearyl (4-hydroxy-3-methyl-5-t-butyl) benzylmalonate, 4-hydroxydimethyl-2,6-di-t-butylphenol, and the like. They may be used alone or in combination of two or more.

As the thioether-based stabilizer, for example,
Dilauryl thiodipropionate, distearyl thiodipropionate, dimyristyl-3,3'-thiodipropionate, ditridecyl-3,3'-thiodipropionate, pentaerythritol-tetrakis- (β
-Lauryl-thiopropionate) and the like, and these may be used alone or as a mixture of two or more.

Examples of the phosphorus-based stabilizer include bis (2,4-di-t-butylphenyl) pentaerythrityl diphosphite, diphenyldecyl phosphite, and the like.
Arylalkyl phosphites such as phenylisooctyl phosphite and 2-ethylhexyldiphenyl phosphite; trimethyl phosphite, triethyl phosphite, tributyl phosphite, trioctadecyl phosphite, distearyl pentaerythrityl diphosphite, and tris (2-chloroethyl ) Phosphites, trialkyl phosphites such as tris (2,3-dichloropropyl) phosphite; tricycloalkyl phosphites such as tricyclohexyl phosphite; triphenyl phosphite, tricresyl phosphite, tris (ethylphenyl) Phosphite, tris (2,4-di-t
Tributyl phosphite, tris (hydroxyphenyl) phosphite and the like; triaryl phosphites such as trimethyl phosphate, triethyl phosphate, tributyl phosphate, trioctadecyl phosphate, distearyl pentaerythrityl phosphate, tris (2-chloroethyl) phosphate and the like; Trialkyl phosphates such as tricyclohexyl phosphate; triaryl phosphates such as triphenyl phosphate, tricresyl phosphate, tris (nonylphenyl) phosphate and 2-ethylphenyl diphenyl phosphate; They may be used or two or more kinds may be mixed.

The hindered amine stabilizers include
For example, bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, 8-benzyl-7,7,9,9
-Tetramethyl-3-octyl-1,2,3-triazaspiro [4,5] undecane-2,4-dione, tetrakis (2,2,6,6-tetramethyl-4-piperidyl) 1,2,3 And 4-butanetetracarboxylate. These may be used alone or as a mixture of two or more.

In the present invention, an epoxy compound can be used as a stabilizer. As such an epoxy compound, a compound having one or more epoxy groups in one molecule is used.

As such epoxy compounds, specifically, epoxidized soybean oil, epoxidized linseed oil, phenylglycidyl ether, t-butylphenylglycidyl ether, 3,4-epoxycyclohexylmethyl-
3 ', 4'-epoxycyclohexylcarboxylate, 3,4-epoxycyclohexylethylene oxide, cyclohexylmethyl-3,4-epoxycyclohexylcarboxylate, 3,4-epoxy-6-methylcyclohexylmethyl-6'-methylcyclohexylcarboxylate , Bisphenol-A diglycidyl ether, diglycidyl ester of phthalic acid, diglycidyl ether of hexahydrophthalic acid, diglycidyl ester of phthalic acid, diglycidyl ester of hexahydrophthalic acid, bis-epoxydicyclopentadienyl ether, Bis-epoxyethylene glycol, bis-epoxycyclohexyl adipate, butadiene diepoxide, tetraphenylethylene epoxide, octyl epoxy tartrate, epoxidation Li butadiene, 3,4-dimethyl-1,2-epoxycyclohexane, 3,5-dimethyl-1,2-epoxycyclohexane, 3-methyl -5-t-butyl-1,2-epoxycyclohexane,
Octadecyl-2,2-dimethyl-3,4-epoxycyclohexylcarboxylate, N-butyl-2,2-
Dimethyl-3,4-epoxycyclohexylcarboxylate, cyclohexyl-2-methyl-3,4-epoxycyclohexylcarboxylate, N-butyl-2,
2-dimethyl-3,4-epoxy-5-methylcyclohexylcarboxylate, octadecyl-3,4-epoxycyclohexylcarboxylate, 2-ethylhexyl-3 ′, 4′-epoxycyclohexylcarboxylate, 4,6-dimethyl-2 , 3-Epoxycyclohexyl-3 ′, 4′-epoxycyclohexylcarboxylate, 4,5-epoxytetrahydrophthalic anhydride, 3-t-butyl-4,5-epoxytetrahydrophthalic anhydride, diethyl-4,5-epoxy -Cis-1,
2-cyclohexyldicarboxylate, di-n-butyl-3-t-butyl-4,5-epoxy-cis-1,2
-Cyclohexyldicarboxylate and the like.

Specific examples of the salicylic acid ultraviolet absorber include phenyl salicylate and pt-butylphenyl salicylate. As the benzophenone-based ultraviolet absorber, 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone,
2,2'-dihydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, 2-hydroxy-4-methoxy-2'-
Carboxybenzophenone, 2-hydroxy-4-methoxy-5-sulfobenzophenone trihydrate, 2-
Hydroxy-4-n-octoxybenzophenone, 2,
2 ', 4,4'-tetrahydroxybenzophenone, 4
-Dodecyloxy-2-hydroxybenzophenone, bis (5-benzoyl-4-hydroxy-2-methoxyphenyl) methane, 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid and the like.

As the benzotriazole ultraviolet absorber, 2- (2'-hydroxy-5'-methylphenyl)
Benzotriazole, 2- (2′-hydroxy-3 ′,
5′-di-t-butylphenyl) benzotriazole,
2- (2'-hydroxy-3'-t-butyl-5'-methylphenyl) -5-chlorobenzotriazole, 2-
(2′-hydroxy-3 ′, 5′-di-tert-butyl-phenyl) -5-chlorobenzotriazole, 2- (2 ′
-Hydroxy-5'-octylphenyl) benzotriazole, 2- (2'-hydroxy-3 ', 5'-diamylphenyl) benzotriazole, 2- [2'-hydroxy-3'-(3 ", 4" , 5 ", 6" -tetrahydrophthalimidomethyl) -5'-methylphenyl] benzotriazole, 2,2'-methylenebis [4- (1,
1,3,3-tetramethylbutyl) -6- (2H-benzotriazol-2-yl) phenol].

Examples of the cyanoacrylate-based ultraviolet absorber include 2-ethylhexyl-2-cyano-3,3-diphenyl acrylate and ethyl-2-cyano-3,3-diphenyl acrylate.

When these compounds are melt-polycondensed with the above aromatic compound dihydroxy compound and diaryl carbonate to produce a polycarbonate, the reaction system has 10 to 40, preferably 15 to 15 carbon atoms as a terminal stopper.
To 40 to 40 mol%, preferably 0.5 to 7 mol%, based on the aromatic organic dihydroxy compound.
Mol%, more preferably 1 to 5 mol%.

As the phenols having 10 to 40 carbon atoms as described above, the following compounds are used. o-
m-butylphenol, p-cyclohexylphenol, o-phenylphenol, m-isobutylphenol, mn-nonylphenol, pt-butylphenol, om-pentylphenol, p-cumylphenol, pm-pentylphenol , O-naphthylphenol, pn-pentylphenol, mn-hexylphenol, 2,6-di-t-butylphenol,
2,4-di-t-butylphenol, 3,5-di-t-
Butylphenol, 2,6-dicumylphenol, 3,
5-Dicumylphenol, 2,2,2-trimethyl-4
Monohydric phenols such as monohydroxychroman derivatives such as-(hydroxyphenyl) chroman are used.

The catalysts used in the above-described amounts are preferably used because the polycondensation reaction can proceed at a sufficient speed and a high molecular weight polycarbonate can be produced with high polymerization activity.

In the presence of such a catalyst, the polycondensation reaction between the aromatic dihydroxy compound and the diaryl carbonate can be carried out under the same conditions as conventionally known polycondensation reactions.

Specifically, the first-stage reaction is carried out at 80 to 25.
0 ° C., preferably 100-230 ° C., more preferably 120-190 ° C., for 0-5 hours, preferably 0 ° C.
The aromatic dihydroxy compound and the diaryl carbonate are reacted under reduced pressure for 4 to 4 hours, more preferably 0 to 3 hours. Next, the reaction temperature is increased while increasing the degree of vacuum of the reaction system, and the reaction between the aromatic dihydroxy compound and the diaryl carbonate is performed. Finally, 5 mmHg or less,
Preferably under a reduced pressure of 1 mmHg or less, 240 to 320
A polycondensation reaction between an aromatic dihydroxy compound and a diaryl carbonate is performed at a temperature of ° C.

The above-mentioned polycondensation reaction may be carried out continuously or batchwise. The reaction apparatus used for performing the above reaction may be a tank type, a tube type, or a tower type.

The polycarbonate, a reaction product obtained as described above, usually has an intrinsic viscosity (methylene chloride solvent (weight ratio: 40/6) measured at 20 ° C.
0)) is from 0.1 to 1.0, preferably from 0.2 to 0.8.

In the present invention, the polycarbonate obtained as described above has ordinary heat stability, an ultraviolet absorber, a releasing agent, a coloring agent, an antistatic agent, a lubricant, and an antifogging agent as long as the object of the present invention is not impaired. , Natural oils, synthetic oils, waxes, organic fillers, inorganic fillers and the like.

[0060]

According to the present invention, it is possible to produce a polycarbonate having a good polymer color tone, suppressing side reactions, and producing less insoluble matter and foreign matter due to a branching reaction even when the degree of polymerization is increased. In addition, the branching reaction and other side reactions are also suppressed during the molding process, and the burn, coloring, insolubilization, and generation of foreign matter in the apparatus can be suppressed to a low level.

[0061]

The present invention will be described below with reference to examples. In the present invention, physical properties were measured according to the following methods. (I) Intrinsic viscosity [η]: Measured in methylene chloride at 20 ° C. with an Ubbelohte viscometer. (Ii) Foreign matter generation: The polymer obtained by treating the polymer in a SUS316 test tube under a nitrogen stream at 290 ° C. for 20 hours was pulverized. 5 g of polymer is 100 m in methylene chloride
and ultrasonically washed and dissolved. The obtained polymer solution was passed through a 1 micron Millipore filter at 0.5 kg / c.
It was filtered under m ² pressure. Filterability is "good" .... Filtering in less than 15 minutes, "Slightly poor" ... Filtering in 15-30 minutes, "Poor" .... Filtering time exceeds 30 minutes. evaluated. The number of black foreign substances on the filter was evaluated in three stages: “small”: less than 10; “medium”: 10 to 20; (Iii) Polymer color tone: (a) L / b: An injection molded plate having a thickness of 3 mm was molded at a cylinder temperature of 300 ° C and an injection pressure of 100 kg / cm2 at a mold temperature of 90 ° C, and the X, Y, and Z values were manufactured by Nippon Denshoku Industries. Color a
nd Color Difference Meter
L / b was measured by a transmission method using ND-1001DP. (B) Haze: NDH manufactured by Nippon Denshoku Industries Co., Ltd.
Measured at -200.

Examples 1 to 6 and Comparative Examples 1 to 4 Bisphenol A (228 parts), diphenyl carbonate (220 parts) and the catalysts of the types and amounts shown in Tables 1, 2 and 3 were mixed with a stirrer, a still and a depressurizer. The reaction vessel provided was charged with nitrogen and then melted at 140 ° C. After stirring for 30 minutes, the internal temperature was raised to 180 ° C., and the pressure was gradually reduced to 100 mm
Phenol reacting with Hg for 30 minutes was distilled off.

Further, the pressure was gradually reduced while the temperature was raised to 200 ° C., and the reaction was carried out while distilling out phenol at 50 mmHg for 30 minutes.

Further, the temperature was gradually raised to 220 ° C. and 30 mmHg, and the pressure was reduced.
0mmHg, 260 ° C 1mmHg, 270 ° C 1mm
The temperature was raised and reduced in the same manner as above until the temperature reached Hg or lower, and the reaction was continued. Finally, polymerization was carried out at the same temperature and pressure for 2 hours to produce a polycarbonate resin.

The physical properties of these polycarbonate resins are shown in Tables 1, 2 and 3.

[0066]

[Table 1]

[0067]

[Table 2]

[0068]

[Table 3]

The polycarbonate produced according to the present invention has a high polymerization rate, has little generation of insoluble foreign matters, and can be filtered quickly. On the other hand, according to Comparative Example 1, the polymerization activity was low and insufficient, and according to Comparative Examples 2 and 3, a large number of gel-like foreign matters were found on the filter during filtration. Was slow, and the hue was deteriorated.
In the polycarbonate produced according to the present invention, when the color tone evaluation injection molded plate was molded, once molding was completed and then molding was resumed, the number of visually observed black foreign matters was kept at a low level.

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Masanori Abe 2-1 Hinode-machi, Iwakuni-shi, Yamaguchi Prefecture Teijin Limited Iwakuni Research Center (56) References JP-A-7-2605 (JP, A) (58) ) Surveyed field (Int.Cl. ⁷ , DB name) C08G 64/00-64/42

Claims (1)

(57) [Claims] 1. A process for producing a polycarbonate by melt-polycondensing an aromatic dihydroxy compound and a diaryl carbonate, wherein (A) a nitrogen-containing basic compound, (B) an alkali metal compound and / or an alkaline earth metal compound, (C) a cyclic aluminum compound represented by the following general formula: [Wherein, R _a , R _b and R _c each independently have 1 to 2 carbon atoms.
Represents a monovalent hydrocarbon group of 0. Wherein the reaction is carried out in the presence of a catalyst comprising: