JPH07196783A - Production of aromatic polycarbonate - Google Patents

Abstract

PURPOSE:To obtain an aromatic polycarbonate, useful for electric devices, having a good color quality and a high heat resistance (a temperature of weight reduction by heat) by using sodium hydroxide having an iron content of not more than a prescribed value. CONSTITUTION:In this process for producing an aromatic polycarbonate by using (A) sodium hydroxide, (B) an aromatic dihydroxy compound, and (C) a precauser of a carbonate, sodium hydroxide containing not more than 2ppm, or preferably not more than 1ppm of iron is used as the component (A). Further, as the component (B), e.g. a compound of the formula (each of Ar<1>, Ar<2> and Ar<3> is a divalent aromatic group; X is a group connecting Ar<1> to Ar<2>), more concretely bis(4-hydroxyphenyl) methane, and as the component (C), carbonyl chloride (phosgene), are preferably used.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing polycarbonate. More specifically, from an aromatic dihydroxy compound and a carbonate precursor using caustic soda,
The present invention relates to a method for producing an aromatic polycarbonate having an excellent color tone.

[0002]

2. Description of the Related Art Conventionally, as a method of producing an aromatic polycarbonate, a method of producing an aromatic polycarbonate from an aromatic dihydroxy compound and a carbonate precursor using caustic soda has been known. By reacting a carbonate precursor such as phosgene with an aqueous caustic soda solution of an aromatic dihydroxy compound in the presence of an organic solvent to prepare a low molecular weight aromatic polycarbonate oligomer containing a haloformate group, and then polycondensing the oligomer. A method for producing a high-molecular-weight aromatic polycarbonate (interfacial polymerization method) has been disclosed [Interscience P
ublishing, "Encyclopedia of Polymer Science and Tec
hnology ", vol.10, Polycarbonate, p.710-764, (1969),
H. Schnell, "Chemistry and Physics of Polycarbonat
e ", Interscience Publishing, p. 9-76, (1964)].
However, the aromatic polycarbonate obtained by the interfacial polymerization method is often yellowish.

Generally, caustic soda used for producing polycarbonate is produced by electrolysis using industrial salt as a raw material by a method such as an ion exchange membrane method and a diaphragm method. For example, in the ion exchange membrane method, salt water is prepared from industrial salt purified using an asbestos diaphragm, and is produced by electrolysis together with chlorine gas and hydrogen gas. The caustic soda obtained by these methods is usually in the state of an aqueous solution, and the caustic soda aqueous solution obtained by the ion exchange membrane method usually gives caustic soda having a concentration of about 20 to 30%. The caustic soda aqueous solution obtained by the diaphragm method is
Usually, the concentration is about 10 to 12%. These caustic sodas are then concentrated in a vacuum evaporator to give an aqueous caustic soda solution having a concentration of about 45 to 50%. After that, these caustic soda aqueous solutions are heated to a temperature at which the caustic soda is melted to remove water, and then cooled and solidified. However, the caustic soda obtained by these methods contains a trace amount of iron,
Since other impurities are contained, when used when producing an aromatic polycarbonate, there is a problem that the produced aromatic polycarbonate is colored.

As a method for suppressing the inclusion of impurities in the reaction system when producing an aromatic polycarbonate, for example, an aromatic dihydroxy compound is reacted with phosgene in the presence of a solvent to produce an aromatic polycarbonate. At this time, phosgene obtained by reacting carbon monoxide with chlorine having a total sulfur concentration of 30 ppm (volume) or less as chlorine is used as phosgene (JP-A-1-275630), organic solvent. In the method for producing an aromatic polycarbonate using methylene chloride as a raw material and phosgene as a raw material, the polymerization is performed such that the concentration of carbon tetrachloride in phosgene and methylene chloride in the polymerization system satisfies the following formula. A method for producing an aromatic polycarbonate (JP-A-62-2973)
21), A + 5B <200 A: carbon tetrachloride concentration in phosgene (ppm) B: carbon tetrachloride concentration in methylene chloride (ppm) In the method for producing an aromatic polycarbonate using phosgene as a raw material, as a raw material phosgene, A method for producing an aromatic polycarbonate characterized in that phosgene having a carbon tetrachloride concentration of 200 ppm or less is introduced into a polymerization system to carry out polymerization (JP-A-62-297320) and the like are disclosed. However, even by these methods, an aromatic polycarbonate having an excellent color tone may not be obtained.

[0005]

SUMMARY OF THE INVENTION The present invention provides a method for solving the above-mentioned problems of the prior art. More specifically, it has excellent color tone and heat resistance (thermal weight reduction temperature).
A method for producing a high aromatic polycarbonate is provided.

[0006]

Means for Solving the Problems The inventors of the present invention diligently studied the cause of deterioration of color tone when producing an aromatic polycarbonate, and used an aromatic dihydroxy compound, caustic soda and a carbonate precursor to produce an aromatic polycarbonate. In the production, it was found that the iron carbonate contained in caustic soda deteriorates the color tone of the produced aromatic polycarbonate, and the heat resistance (the reduction in thermogravimetric weight) is lowered, and the present invention has been accomplished. That is, the present invention relates to a method for producing an aromatic polycarbonate from an aromatic dihydroxy compound and a carbonate precursor using caustic soda, and a method for producing an aromatic polycarbonate using caustic soda having an iron content of 2 ppm or less. Out.

The caustic soda used in the present invention has a content of iron of 2 ppm or less, preferably 1 ppm or less. It has been found that caustic soda generally contains a small amount of iron and other inorganic impurities, which deteriorates the color tone of the aromatic polycarbonate during the production of the aromatic polycarbonate. The present inventors investigated the relationship between the iron content in caustic soda and the color tone of the aromatic polycarbonate in order to improve the color tone of the aromatic polycarbonate. In general, solid caustic soda contains up to about 500 ppm of iron, and usually such iron content often occurs when concentrating caustic soda.

In order to use an aqueous solution of caustic soda having an iron content of 2 ppm or less, for example, the following method can be adopted. A: When the aqueous caustic soda solution is concentrated, a caustic soda aqueous solution or solid caustic soda obtained by using a glass lining or a concentrating tank made of a material such as titanium or a heating tube is used. B: The aqueous caustic soda solution obtained in the electrolytic cell is used without being concentrated. The caustic soda used in the production method of the present invention has an iron content of 2 ppm or less, but the iron content represents the iron content in the solid or aqueous caustic soda, and preferably 20 to 20 ppm. It represents the content of iron in a 50% by weight aqueous sodium hydroxide solution. By using such a caustic soda having a low iron content, the color tone of the present invention is excellent and the heat resistance (thermal weight reduction temperature) is high.
It becomes possible to produce an aromatic polycarbonate having a high viscosity.

The aromatic dihydroxy compound, carbonate precursor, tertiary amine, water, organic solvent, molecular weight modifier and branching agent used in the present invention will be described in detail below. The aromatic dihydroxy compound used in the production method of the present invention is a compound represented by the general formula (1) or (2). HO-Ar ¹ -X-Ar ² -OH (1) HO-Ar ³ -OH (2) (In the formula, Ar ¹ , Ar ² and Ar ³ are each a divalent aromatic group, and X is Ar ¹ In the general formula (1) or (2), which represents a linking group for connecting Ar ² , Ar ¹ , Ar ² and Ar
Each of ³ 's represents a divalent aromatic group, preferably a phenylene group. Further, the phenylene group may have a substituent, and as the substituent, a halogen atom, a nitro group,
Examples thereof include an alkyl group, a cycloalkyl group, an alkenyl group, an aralkyl group, an aryl group and an alkoxy group.

Ar ¹ and Ar ² are both p-phenylene group, m-phenylene group or o-phenylene group, or one is p-phenylene group and the other is m-phenylene group or o-phenylene group. It is preferable that both Ar ¹ and Ar ² are p-phenylene groups. Ar ³ is a p-phenylene group, m-phenylene group or o-phenylene group, and preferably a p-phenylene group or m-phenylene group. X is Ar ¹ and Ar ²
A linking group that binds a single bond or a divalent hydrocarbon group, and further -O-, -S-, -SO-, -SO.
It may be a group containing atoms other than carbon and hydrogen, such as _2- and -CO-. The divalent hydrocarbon group means, for example, an alkylidene group such as a methylene group, an ethylene group, a 2,2-propylidene group, a cyclohexylidene group, an alkylidene group substituted with an aryl group, an aromatic group or other It is a hydrocarbon group containing a saturated hydrocarbon group.

Specific examples of the aromatic dihydroxy compound include bis (4-hydroxyphenyl) methane, 1,1-bis (4'-hydroxyphenyl) ethane, 1,2-bis (4'-hydroxyphenyl) ethane, Bis (4-hydroxyphenyl) phenylmethane, bis (4-hydroxyphenyl) diphenylmethane, 1,1-bis (4'-hydroxyphenyl) -1-phenylethane, 2,2-bis (4'-hydroxyphenyl) propane ["Bisphenol A"], 2- (4'-
Hydroxyphenyl) -2- (3'-hydroxyphenyl) propane, 2,2-bis (4'-hydroxyphenyl) butane,
1,1-bis (4'-hydroxyphenyl) butane, 1,1-bis (4'-hydroxyphenyl) -2-methylpropane, 2,2-
Bis (4'-hydroxyphenyl) -3-methylbutane, 2,
2-bis (4'-hydroxyphenyl) pentane, 3,3-bis (4'-hydroxyphenyl) pentane, 2,2-bis (3'-
Methyl-4′-hydroxyphenyl) propane, 2,2-bis (3′-isopropyl-4′-hydroxyphenyl) propane, 2,2-bis (3′-sec-butyl-4′-hydroxyphenyl) propane, 2,2-bis (3'-tert-butyl-
4'-hydroxyphenyl) propane, 2,2-bis (3'-cyclohexyl-4'-hydroxyphenyl) propane, 2,
2-bis (3'-allyl-4'-hydroxyphenyl) propane, 2,2-bis (3 ', 5'-dimethyl-4'-hydroxyphenyl) propane, 2,2-bis (3'-chloro- 4'-hydroxyphenyl) propane, 2,2-bis (3 ', 5'-dichloro-4'-
Hydroxyphenyl) propane, 2,2-bis (3'-bromo-4'-hydroxyphenyl) propane, 2,2-bis (3 ',
5'-dibromo-4'-hydroxyphenyl) propane, 2,2
-Bis (hydroxyaryl) alkanes such as bis (4'-hydroxyphenyl) hexafluoropropane,

1,1-bis (4'-hydroxyphenyl) cyclopentane, 1,1-bis (4'-hydroxyphenyl) cyclohexane, 1,1-bis (4'-hydroxyphenyl) cycloheptane, 1,1 -Bis (3'-methyl-4'-hydroxyphenyl) cyclohexane, 1,1-bis (3 ', 5'-dimethyl-
4'-hydroxyphenyl) cyclohexane, 1,1-bis (3 ', 5'-dichloro-4'-hydroxyphenyl) cyclohexane, 1,1-bis (4'-hydroxyphenyl) -3,3,5-trimethyl Cyclohexane, 2,2-bis (4'-hydroxyphenyl) norbornane, bis (hydroxyaryl) cycloalkanes such as 2,2-bis (4'-hydroxyphenyl) adamantane, 4,4'-dihydroxydiphenyl ether, 3, Bis (hydroxyaryl) ethers such as 3'-dimethyl-4,4'-dihydroxydiphenyl ether and ethylene glycol bis (4-hydroxyphenyl) ether, 4,4'-dihydroxydiphenyl sulfide, 3,3'-
Dimethyl-4,4'-dihydroxydiphenyl sulfide, 3,
Bis (hydroxyaryl) sulfides such as 3 ', 5,5'-tetramethyl-4,4'-dihydroxydiphenyl sulfide, 4,4'-dihydroxydiphenyl sulfoxide, 4,4'
-Bis (hydroxyaryl) sulfoxides such as dihydroxy-3,3'-dimethyldiphenylsulfoxide, 4,4 '
-Bis (hydroxyaryl) sulfones such as dihydroxydiphenylsulfone, 4,4'-dihydroxy-3,3'-dimethyldiphenylsulfone, bis (4-hydroxyphenyl) ketone, bis (3-methyl-4-hydroxyphenyl) Bis (hydroxyaryl) ketones such as ketones,

Further, 6,6'-dihydroxy-3,3,3 ', 3'-
Tetramethyl spiro (bis) indan ["spirobiindane bisphenol"], 7,7'-dihydroxy-3,3 ', 4,
4'-tetrahydro-4,4,4 ', 4'-tetramethyl-2,2'-spirobi (2H-1-benzopyran), trans-2,3-bis (4'-hydroxyphenyl) -2-butene , 9,9-bis (4 '
-Hydroxyphenyl) fluorene, 1,6-bis (4'-hydroxyphenyl) -1,6-hexanedione, α, α,
α ', α'-tetramethyl-α, α'-bis (4-hydroxyphenyl) -p-xylene, α, α, α', α'-
Tetramethyl-α, α′-bis (4-hydroxyphenyl) -m-xylene, 4,4′-dihydroxybiphenyl, hydroquinone, resorcin and the like can be mentioned. Further, for example, an aromatic dihydroxy compound containing an ester bond which can be produced by reacting 2 mol of bisphenol A with 1 mol of isophthaloyl chloride or terephthaloyl chloride is also useful. These may be used alone or in combination of two or more. In the production method of the present invention, it is preferable to use bisphenol A from the viewpoint of easy availability and various physical properties of the produced aromatic polycarbonate.

Examples of the carbonate precursor used in the present invention include carbonyl halide compounds, mono- or bishaloformate derivatives of dihydroxy compounds, and oligomers of mono- or bishalomate derivatives of dihydroxy compounds. Specific examples include carbonyl halides such as carbonyl chloride (phosgene), carbonyl bromide, carbonyl iodide and mixtures thereof, trichloromethylchloroformate which is a dimer of phosgene, and bis which is a trimer of phosgene. A haloformate of a dihydroxy compound derived from a dihydroxy compound such as (trichloromethyl) carbonate, 2,2-bis (4'-chlorocarbonyloxyphenyl) propane and 1,2-bis (chlorocarbonyloxy) ethane and a carbonyl halide compound. Derivatives can be mentioned.

The relationship between the molar ratios of the aromatic dihydroxy compound, caustic soda, and the carbonate precursor used in the production of the aromatic polycarbonate by the production method of the present invention is as follows. Let β be the number of moles of 1 ≦ β / α,
Preferably, 1 ≦ β / α ≦ 2. When β is the equivalent of caustic soda, 4β-2α ≦ γ, preferably 4β-2α ≦ γ ≦ 4β-2α + 0.5α. When β / α is 1 or less, a hydroxy-terminated aromatic polycarbonate is obtained because the amount of the carbonyl halide compound is insufficient with respect to the aromatic hydroxy compound. When β / α is 2 or more, a carbonyl halide compound that does not participate in the reaction is produced. When γ is 4β-2α or less, a haloformate-terminated aromatic polycarbonate is obtained. When γ is 4β-2α or more, no particular advantage is found.

In the production method of the present invention, a catalyst may be used if desired. The catalyst used is 3
Examples thereof include secondary amines, quaternary ammonium salts, tertiary phosphines, quaternary phosphonium salts, nitrogen-containing heterocyclic compounds and salts thereof, imino ethers and salts thereof, and compounds having an amide group. A tertiary amine is preferable, a trialkylamine is more preferable, and a trialkylamine having an alkyl group of C _{1 to} C ₈ is further preferable. As a specific example, for example, triethylamine,
Examples thereof include tri-n-propylamine, diethyl-n-propylamine, tri-n-butylamine, N, N-dimethylcyclohexylamine and N, N-diethylcyclohexylamine.

In the production method of the present invention, caustic soda is usually used in the form of an aqueous solution, but if desired, water may be further added to carry out the reaction. The amount of water used in producing the aromatic polycarbonate is the sum of the amount of water contained in the aqueous solution of caustic soda and the amount of water to be added if desired, and the molar amount of the aromatic dihydroxy compound used in producing the aromatic polycarbonate. 0.5 to number
It is preferably 2.5 liters / mole, and 0.6 to
It is more preferably 2.2 liters / mole,
It is more preferably 7 to 2.0 liters / mole, and particularly preferably 0.8 to 1.8 liters / mole.

The organic solvent used in the production method of the present invention is substantially insoluble in water, inert to the reaction, and capable of dissolving the aromatic polycarbonate oligomer and / or the aromatic polycarbonate. It can be used as desired. As the organic solvent, dichloromethane, 1,2-dichloroethane, 1,2-dichloroethylene, trichloroethane, tetrachloroethane, aliphatic chlorinated hydrocarbons such as dichloropropane, chlorobenzene,
It is possible to use aromatic chlorinated hydrocarbons such as dichlorobenzene, or mixtures thereof. Further, it is also possible to use an organic solvent in which an aromatic hydrocarbon such as toluene, xylene and ethylbenzene, an aliphatic hydrocarbon such as hexane, heptane and cyclohexane is mixed with the chlorinated hydrocarbon or a mixture thereof. is there. Dichloromethane is preferred because of its excellent ability to dissolve an aromatic polycarbonate.

The amount of the organic solvent is usually preferably such that the concentration of the aromatic polycarbonate in the organic solvent solution of the aromatic polycarbonate at the end of the polycondensation reaction is about 5 to 35% by weight, and about 10 to 20% by weight. Is more preferable.
When the concentration of the aromatic polycarbonate in the organic solvent solution of the aromatic polycarbonate is extremely low, a large amount of the organic solvent is required, resulting in poor production efficiency. Further, when the concentration of the aromatic polycarbonate in the organic solvent solution of the aromatic polycarbonate is a concentration close to the saturated state, the viscosity of the organic solvent solution of the aromatic polycarbonate becomes very high, so that the efficiency of the interfacial polymerization reaction decreases. Problems such as deterioration of handleability after polymerization occur.

In the method for producing an aromatic polycarbonate of the present invention, a molecular weight modifier and a branching agent may be used if desired. The molecular weight modifier used if desired,
It is a compound having a function of controlling the molecular weight during the production of an aromatic polycarbonate, and a monovalent hydroxyaromatic compound is generally used. Specific examples include phenol, p-tert-butylphenol, p-cresol, p-cumylphenol, p-phenylphenol,
p-cyclohexylphenol, p-octylphenol, p-nonylphenol, p-methoxyphenol,
p-isopropenylphenol, o-chlorophenol, m-chlorophenol, p-chlorophenol, o
-Bromophenol, m-bromophenol, p-bromophenol, pentabromophenol, pentachlorophenol and the like. Phenol, p-cumylphenol or p-tert-butylphenol is preferable from the viewpoint of easy availability.

The aromatic polycarbonate of the present invention preferably has a weight average molecular weight of about 10,000 to about 100,000, more preferably about 30,000 to 70,000. The weight average molecular weight of the aromatic polycarbonate can be controlled by adjusting the amount of the molecular weight modifier used, if desired. It is also within the scope of the present invention to produce a branched aromatic polycarbonate by adding a branching agent if desired. The branching agent optionally added is an aromatic hydroxy group, a haloformate group,
Carboxyl groups, carbonyl halide groups, compounds having three or more reactive groups selected from active halogen atoms (may be the same or different), for example, phloroglucinol, 4,6-dimethyl-2,4,6- Tris (4'-hydroxyphenyl) -2-heptene, 4,6-dimethyl-2,4,6-tris (4'-hydroxyphenyl) heptane, 1,3,5-tris (
4'-hydroxyphenyl) benzene, 1,1,1-tris (4 '
-Hydroxyphenyl) ethane, 1,3,5-tris (4'-hydroxyphenylisopropyl) benzene, α, α, α '
-Tris (4'-hydroxyphenyl) -1-ethyl-4
-Isopropylbenzene, tris (4'-hydroxyphenyl) phenylmethane, 2,6-bis (2-hydroxy-5'-methylbenzyl) -4-methylphenol, trimesic acid trichloride, cyanuric chloride, 3,5- Examples thereof include dihydroxybenzoic acid and 5-hydroxyisophthalic acid.
The amount of the branching agent is adjusted according to the degree of branching of the desired branched aromatic polycarbonate, but usually it is 0.05 to 2. per mol of the aromatic dihydroxy compound.
It is preferably about 0 mol%.

The production method of the present invention is usually carried out at a temperature of about 10 ° C. to the boiling point of the organic solvent used in the reaction. Further, it is usually carried out under atmospheric pressure, and if desired, it can be carried out under atmospheric pressure or under atmospheric pressure. The production method of the present invention is usually carried out by mixing the reaction mixture. The mixing may be performed to such an extent that the separation of the organic phase and the aqueous phase is prevented, and is usually performed to such an extent that the organic phase and the aqueous phase are uniformly mixed. Normally, mixing is performed by a tank type stirrer, a static mixer,
The preferable mixing conditions performed using an orifice mixer or the like cannot be uniquely expressed depending on the shape of the reaction apparatus, the mixing efficiency, etc., but the preferable mixing conditions can be determined by a simple experiment. Further, the mixing does not always have to be a constant condition during the process of producing the aromatic polycarbonate, and for example, after producing a low molecular weight aromatic polycarbonate oligomer, the polycondensation reaction is efficiently performed by violently mixing conditions. You can also

The method for producing an aromatic polycarbonate of the present invention is carried out by reacting a caustic soda aqueous solution of an aromatic dihydroxy compound with a carbonyl halide compound under a two-phase interface condition of an organic solvent and water. The reaction between the carbonyl halide compound and the aromatic dihydroxy compound may be carried out batchwise under stirring in an aqueous solution of sodium hydroxide, or while the carbonyl compound is supplied to the caustic soda solution of the organic solvent and the aromatic dihydroxy compound. You can also Further, in a continuous manner, a carbonyl halide compound is contacted with a caustic soda aqueous solution of an aromatic dihydroxy compound in the presence of an organic solvent to form a low molecular weight aromatic polycarbonate oligomer, and then the aromatic polycarbonate oligomer is optionally present in the presence of a catalyst. It is also possible to perform polycondensation below.

The reaction mixture containing the aromatic polycarbonate produced according to the present invention is then subjected to post-treatment by continuous operation or batch operation, preferably continuous operation, to recover the aromatic polycarbonate. Work-up of the reaction mixture is
The organic solvent phase containing the aromatic polycarbonate and the aqueous phase are separated, and then the organic solvent phase containing the aromatic polycarbonate is washed with water or a dilute aqueous alkaline solution, if necessary, and further neutralized with a dilute aqueous acid solution. To do. Examples of the acid used here include mineral acids such as hydrochloric acid, sulfuric acid and phosphoric acid. After that, washing with water is further repeated until the electrolyte is substantially absent. Then, the organic solvent is removed from the washed organic solvent solution of the aromatic polycarbonate by a known method to recover the aromatic polycarbonate. As a method of removing the organic solvent from the organic solvent solution of the aromatic polycarbonate and recovering the aromatic polycarbonate, a method of removing the organic solvent by distillation or steam distillation, or an organic solvent that does not dissolve the aromatic polycarbonate (poor solvent) Can be added to an organic solvent solution of an aromatic polycarbonate to make the aromatic polycarbonate in a solid state, and the organic solvent is separated from the obtained organic solvent slurry of the aromatic polycarbonate by a method such as filtration.

More specifically, the aromatic polycarbonate is crystallized by distilling off a predetermined amount of the organic solvent from the organic solvent solution of the aromatic polycarbonate to bring the organic solvent solution of the aromatic polycarbonate into a saturated state. A method of pulverizing and then drying to remove the contained organic solvent, a method of immediately heating the aromatic polycarbonate in a molten state while pelletizing it by heating while removing the organic solvent directly from the organic solvent solution of the aromatic polycarbonate, A method of pulverizing a gel-like substance produced while removing the organic solvent by supplying the organic solvent solution of the aromatic polycarbonate to warm water, a poor solvent or non-solvent for the aromatic polycarbonate in the organic solvent solution of the aromatic polycarbonate, and water Is added, and the mixture is heated and concentrated to give a solid aromatic poly Method of obtaining carbonate as an aqueous slurry, obtaining an aromatic polycarbonate in a solid state as an aqueous slurry by adding an organic solvent solution of an aromatic polycarbonate to warm water containing powder of the aromatic polycarbonate and evaporating and distilling off the organic solvent Method, while the organic solvent solution of the aromatic polycarbonate is supplied into the warm water containing the powder of the aromatic polycarbonate and the poor solvent for the aromatic polycarbonate, the organic solvent is distilled off, and the solid state aromatic polycarbonate is made into a water slurry. A method of obtaining the same can be mentioned.

As the poor solvent or non-solvent for the aromatic polycarbonate used here, aromatic hydrocarbons such as toluene and xylene, aliphatic hydrocarbons such as pentane, hexane, octane, cyclohexane and methylcyclohexane, methanol, Examples thereof include alcohols such as ethanol, propanol, butanol, pentanol, and hexanol, acetone, methyl ethyl ketone, diethyl ketone, methyl isobutyl ketone, cyclohexanone, and other ketones, and ethyl acetate, butyl acetate, amyl acetate, and other esters.

The aromatic polycarbonate produced according to the present invention can be mixed with other polymers and used as a molding material. Other polymers include
Polyethylene, polypropylene, polystyrene, ABS
Examples thereof include resins, polymethylmethacrylate, polyphenylene oxide, polybutylene terephthalate, polyethylene terephthalate, polyamides, polyimides, polyamideimides, and polyethersulfone polyarylates. Aromatic polycarbonate produced by the production method of the present invention, alone or in combination with other polymers,
It is also possible to add known additives such as pigments, dyes, heat stabilizers, ultraviolet absorbers, release agents, flame retardants and the like. The aromatic polycarbonate produced according to the present invention, alone or in a state of being mixed with another polymer, is added with the above-mentioned additives, if desired, as a molding material, such as a chassis or housing material for electric equipment, electronic parts, automobile parts. It can be molded into a substrate of an information recording medium such as a compact disc, an optical material such as a lens of a camera or spectacles, a building material instead of glass, and the like. Aromatic polycarbonate produced by the production method of the present invention, injection molding in the molten state, extrusion molding,
Blow molding, impregnation with a filler and the like are possible, and can be easily molded by a known molding method.

[0028]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to the following examples. Table 1 (Table 1) shows Examples 1 to 3 and Comparative Examples 1 to 1.
The iron content of the caustic soda used in 4 and the physical properties of the obtained aromatic polycarbonate were summarized. The physical properties of each example and comparative example were measured by the following methods. -Molecular weight: A 0.2 wt% chloroform solution of aromatic polycarbonate was measured by GPC (gel permeation chromatography) [System-11 manufactured by Showa Denko KK] to obtain a weight average molecular weight. The measured values are standard polystyrene equivalent values. -Iron content in caustic soda: The iron content in caustic soda was measured by the atomic absorption method.・ 5% weight loss temperature: Thermobalance [DT manufactured by Shimadzu Corporation
G-40 series] at 10 ° C / min in air atmosphere. -YI value: The produced aromatic polycarbonate powder was formed into a press sheet having a thickness of 1 mm with a hot press machine, and the YI value was obtained with a color difference meter (manufactured by Suga Test Instruments Co., Ltd.).

Example 1 A baffled flask having an internal capacity of 10 liters was equipped with a stirrer having a Maxblend blade, a reflux cooling tube, and a dipping tube for blowing phosgene. 912g in this flask
(4.0 mol) bisphenol A, 20.64 g
(0.1376 mol, 3.4 with respect to bisphenol A
(4 mol%) p-tert-butylphenol, 4 liters of dichloromethane, 4 liters of deionized water were added to form a suspension, and a nitrogen purge was performed to remove oxygen in the flask. Next, 1.2 g of sodium hydrosulfite was added to the above suspension, and further about 30% by weight.
The caustic soda aqueous solution (containing 1 ppm or less of iron) was added to dissolve bisphenol A. In this two-phase mixture,
7.78 g of 466.9 g (4.72 mol) of phosgene
It was blown at the feeding rate of. After the phosgene feed was complete, 0.64 g of triethylamine was added and the reaction mixture was mixed for a further 60 minutes. Then, the reaction solution was allowed to stand, the organic phase was separated, neutralized with hydrochloric acid, and washed with deionized water until the electrolyte was exhausted. To the dichloromethane solution of the aromatic polycarbonate thus obtained, 2 liters of toluene and 5 liters of water were added.
Dichloromethane and toluene were distilled off by heating to 8 ° C to obtain a polycarbonate powder.

Examples 2 to 3 An aromatic polycarbonate was produced in the same manner as in Example 1 except that about 30% by weight of a caustic soda aqueous solution containing the amount of iron shown in Table 1 was used. The results are shown in Table-1.

Comparative Examples 1 to 4 An aromatic polycarbonate was produced in the same manner as in Example 1 except that an aqueous caustic soda solution containing about 30% by weight of iron as shown in Table 1 was used. The results are shown in Table-1.

[Table 1] As is clear from Table 1, the aromatic polycarbonate produced using caustic soda containing iron in a concentration within the range of the present invention is excellent in color tone and also has high heat resistance (thermal weight reduction temperature). I understand.

[0032]

By the manufacturing method of the present invention, the color tone is excellent,
Further, it has become possible to produce an aromatic polycarbonate having high heat resistance (thermal weight reduction temperature).

 ─────────────────────────────────────────────────── (72) Inventor Masakatsu Nakatsuka 1190 Kasama-cho, Sakae-ku, Yokohama-shi, Kanagawa Mitsui Toatsu Chemical Co., Ltd. (72) Akihiro Yamaguchi 1190 Kasama-cho, Sakae-ku, Yokohama, Kanagawa Mitsui Toatsu Chemical Within the corporation

Claims (1)

[Claims] 1. A method for producing an aromatic polycarbonate from an aromatic dihydroxy compound and a carbonate precursor using caustic soda, wherein the content of iron is 2
A method for producing an aromatic polycarbonate, which comprises using sodium hydroxide in an amount of ppm or less.