JPH07233253A - Production of aromatic polycarbonate - Google Patents

Abstract

PURPOSE:To produce an aromatic polycarbonate excellent in color tone and heat resistance. CONSTITUTION:This production process is one for producing an aromatic polycarbonate from an aromatic dihydroxy compound and a carbonate precursor in the presence of sodium hydrosulfite, wherein the sodium hydrosulfite used is one having a purity of 85wt.% or above.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing an aromatic polycarbonate.

[0002]

2. Description of the Related Art Conventionally, aromatic polycarbonate has been
It is known to be produced from an aromatic dihydroxy compound and a carbonate precursor. At this time, for the purpose of preventing coloration of the produced aromatic polycarbonate, for example, an antioxidant such as sodium hydrosulfite is used. Are used (eg US Pat. No. 3,028,365).
No., German Patent No. 971790). In general, because sodium hydrosulfite has a strong reducing property, it easily reacts with oxygen in the presence of moisture to be oxidatively decomposed. It is also known that an acidic substance is produced by self-decomposition. Therefore, conventionally, basic substances such as sodium carbonate, sodium sulfite, sodium silicate, sodium phosphate, and hexamine have been added as stabilizers to commercially available sodium hydrosulfite.

However, since the effects of these stabilizers are not sufficient, they are inevitably decomposed to some extent during storage, and those that have been opened need to be used promptly, which is a considerable limitation in use. There is. It is also disclosed that such a tendency is particularly noticeable in sodium hydrosulfite produced by sodium formate, sulfurous acid and sodium hydroxide, which is a so-called sodium formate method (Japanese Patent Publication No. 46-38408). Issue). Thus, since sodium hydrosulfite is extremely unstable, its purity may be significantly lowered depending on its storage condition. When an aromatic polycarbonate is produced using such low-purity sodium hydrosulfite, the obtained aromatic polycarbonate is colored and the heat resistance (5% weight loss temperature) of the obtained aromatic polycarbonate is remarkable. It turned out to fall.

[0004]

An object of the present invention is to provide a method for producing an aromatic polycarbonate which is excellent in color tone and heat resistance (5% weight loss temperature).

[0005]

Means for Solving the Problems The inventors of the present invention proceeded with an examination by paying attention to the above phenomenon, and produced an aromatic polycarbonate by using sodium hydrosulfite having a purity of 85% by weight or more. The aromatic polycarbonate has been found to be excellent in color tone and heat resistance (5% weight loss temperature), and has reached the present invention. That is, the present invention, in the presence of sodium hydrosulfite,
The present invention relates to a method for producing an aromatic polycarbonate using sodium hydrosulfite having a purity of 85% by weight or more when producing an aromatic polycarbonate from an aromatic dihydroxy compound and a carbonate precursor.

The sodium hydrosulfite used in the present invention is a sodium hydrosulfite having a purity of 85% by weight or more, preferably 90% by weight or more, more preferably 92% by weight or more. When an aromatic polycarbonate is produced by using sodium hydrosulfite having a purity lower than 85% by weight, the obtained aromatic polycarbonate is colored yellow and its heat resistance (5% weight loss temperature) is remarkably lowered. Tend. The method for producing sodium hydrosulfite used in the present invention is not particularly limited, and any known method such as so-called sodium formate method, amalgam method or zinc method may be used. For example, according to the sodium formate method, sodium hydrosulfite is produced by adding an aqueous solution of sodium hydroxide and anhydrous sulfite to an aqueous alcohol solution of sodium formate at an appropriate rate and reacting with heating while stirring. You can

The sodium hydrosulfite thus produced is usually stored in a sufficiently dry nitrogen atmosphere. Generally, the purity of commercially available sodium hydrosulfite is 90.0% by weight or more in the special issue and 85.0% by weight or more in the No. 1 according to JIS K-1476. Therefore, in the present invention, either the special issue or the special issue can be used. However, as described above, sodium hydrosulfite is very sensitive to the presence of slight moisture and oxygen, and once a decomposition product is generated, it accelerates the decomposition of sodium hydrosulfite. therefore,
Once opened, the purity may be significantly reduced even when stored in a sufficiently dry nitrogen atmosphere. In addition, even if it is not developed, the purity of the product that has been stored for a long period of time may be significantly reduced due to self-decomposition. In such a case, it is necessary to purify sodium hydrosulfite and adjust the purity of sodium hydrosulfite to a desired value before use.

The method for purifying sodium hydrosulfite is not particularly limited, and it can be purified by a known method, for example, the method disclosed in JP-B-46-18374. That is, low-purity sodium hydrosulfite, water, or, dissolved in water-alcohol, crystallized and collected sodium hydrosulfite dihydrate, water, or, with a saturated salt solution of alcohol water, Sodium hydrosulfite can be purified by heat-treating the free water in the presence of sodium chloride, which is required to substantially saturate the free water, and collecting the thus-formed anhydrous salt. The purity of sodium hydrosulfite is usually measured according to JIS K-1476. That is, the purity of sodium hydrosulfite can be determined by dissolving sodium hydrosulfite in a neutral formalin solution and then titrating it with an iodine solution using a starch solution as an indicator under acidic hydrochloric acid.

In the production method of the present invention, at least one aromatic dihydroxy compound, a carbonate precursor, and sodium hydrosulfite having a purity of 85% by weight or more are used. Examples of the manufacturing method of the present invention include "Encyclopedia of PolymerScience and Technolog".
y "vol.10, Polycarbonate, Interscience Publishing,
p.710-725 (1969), H. Schnell, "Chemistry and Physic.
s of Polycarbonate ", Interscience Publishing, p31-51
The method described in (1964), for example, the interfacial polymerization method can be used. That is, a method for producing an aromatic polycarbonate from an aromatic dihydroxy compound and a carbonate precursor in a two-phase mixed solvent of an organic solvent and an aqueous base solution containing sodium hydrosulfite having a purity of 85% by weight or more is applied. can do. At this time, it is preferable to use a molecular weight modifier.
Also, a polycarbonate-forming catalyst may be used if desired.

The aromatic dihydroxy compound used in the present invention includes compounds represented by the general formula (1) or the general formula (2). HO-Ar ¹ -X-Ar ² -OH (1) HO-Ar ³ -OH (2) (In the formula, Ar ¹ , Ar ² and Ar ³ represent a divalent aromatic group, and X represents Ar ¹ and Represents a linking group for connecting Ar ² ) In the general formulas (1) and (2), Ar ¹ , Ar ²
And Ar ³ each represent a divalent aromatic group, preferably a phenylene group, and the phenylene group may have a substituent. As the substituent, an alkyl group, a cycloalkyl group, an alkenyl group, an aryl group, an alkoxy group,
Examples thereof include a halogen atom and a nitro group. General formula (1)
In the above, both Ar ¹ and Ar ² are 1,4-phenylene group, 1,3-phenylene group or 1,2-phenylene group, or one is 1,4-phenylene group and one is 1, It is preferably a 3-phenylene group or a 1,2-phenylene group, and it is particularly preferable that both Ar ¹ and Ar ² are 1,4-phenylene groups. In the general formula (2), Ar ³ is a 1,4-phenylene group, a 1,3-phenylene group or a 1,2-phenylene group, and preferably,
It is a 1,4-phenylene group or a 1,3-phenylene group.

In the general formula (1), X is Ar ¹ and Ar ^2.
Is a linking group for connecting a single bond or a divalent hydrocarbon group, and further -O-, -S-, -SO-, -SO ₂
It may be a group containing an atom other than carbon and hydrogen, such as-or -CO-. Here, the divalent hydrocarbon group includes a saturated hydrocarbon group, for example, an alkylidene group such as a methylene group, an ethylene group, a 2,2-propylidene group and a cyclohexylidene group. It also includes a hydrocarbon group substituted with an aryl group or the like, and may be a hydrocarbon group containing an aromatic group or another unsaturated hydrocarbon group.

Specific examples of the aromatic dihydroxy compound include bis (4-hydroxyphenyl) methane and 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, 1,1-bis (4'-
Hydroxyphenyl) butane, 2,2-bis (4'-hydroxyphenyl) butane, 1,1-bis (4'-hydroxyphenyl) -3-methylbutane,

2,2-bis (4'-hydroxyphenyl)
Pentane, 2,2-bis (4'-hydroxyphenyl)-
4-methylpentane, 4,4-bis (4'-hydroxyphenyl) heptane, bis (3,5-dimethyl-4-hydroxyphenyl) methane, 2,2-bis (3'-methyl-
4'-hydroxyphenyl) propane, 2,2-bis (3 '
-Isopropyl-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,
Bis (hydroxyaryl) alkanes such as 2,2-bis (3 ′, 5′-dibromo-4′-hydroxyphenyl) propane and 2,2-bis (4′-hydroxyphenyl) hexafluoropropane,

1,1-bis (4'-hydroxyphenyl)
Cyclopentane, 1,1-bis (4'-hydroxyphenyl) cyclohexane, 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-trimethylcyclohexane, 1,1-bis (4'-hydroxyphenyl) cycloheptane, 2,2-bis (4'-hydroxyphenyl) norbornane, 2,2-bis (4 ' -Hydroxyphenyl) adamantane and other bis (hydroxyaryl) cycloalkanes, 4,4'-dihydroxydiphenyl ether, 3,3'-dimethyl-4,4'-dihydroxydiphenyl ether, ethylene glycol bis (4-hydroxyphenyl) ether, etc. Bis (hydroxyaryl)
Ethers,

4,4'-dihydroxydiphenyl sulfide, 3,3'-dimethyl-4,4'-dihydroxydiphenyl sulfide, 3,3'-dicyclohexyl-4,4'-dihydroxydiphenyl sulfide, 3,3'-diphenyl -4,4'-dihydroxydiphenyl sulfide, 3,
Bis (hydroxyaryl) sulfides such as 3 ', 5,5'-tetramethyl-4,4'-dihydroxydiphenyl sulfide, 4,4'-dihydroxydiphenyl sulfoxide, 3,3'-dimethyl-4,4'- Bis (hydroxyaryl) sulfoxides such as dihydroxydiphenyl sulfoxide, 4,4′-dihydroxydiphenyl sulfone,
Bis such as 3,3'-dimethyl-4,4'-dihydroxydiphenyl sulfone, 3,3'-diphenyl-4,4'-dihydroxydiphenyl sulfone, 3,3'-dichloro-4,4'-dihydroxydiphenyl sulfone (Hydroxyaryl) sulfones, bis (4-hydroxyphenyl) ketone, bis (3-methyl-4-hydroxyphenyl) ketone and other bis (hydroxyaryl) ketones,

Further, 6,6'-dihydroxy-2,2 ',
3,3'-Tetrahydro-3,3,3 ', 3'-tetramethyl-1,1'-spirobi (1H-indene) ["spirobiindanebisphenol"], 7,7-dihydroxy-
3,3 ′, 4,4′-tetrahydro-4,4,4 ′, 4′-tetramethyl-2,2′-spirobi (2H-1-benzopyran) [“spirobichroman”], 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) -1,4-xylene,
α, α, α ′, α′-tetramethyl-α, α′-bis (4′-hydroxyphenyl) -1,3-xylene, 4,
4′-dihydroxybiphenyl, 1,4-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, hydroquinone, resorcin and the like can be mentioned. Furthermore, for example,
Aromatic dihydroxy compounds containing an ester bond, which are produced by reacting 2 mol of bisphenol A with 1 mol of isophthaloyl chloride or terephthaloyl chloride are also useful. These may be used alone or in combination. Particularly preferably used aromatic dihydroxy compounds are bis (hydroxyaryl) alkanes and bis (hydroxyaryl) cycloalkanes, and among them, bisphenol A is preferable.

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 bishaloformate derivatives of dihydroxy compounds. Specific examples include carbonyl halide compounds such as carbonyl chloride (phosgene), carbonyl bromide, carbonyl iodide, carbonyl fluoride and mixtures thereof. In addition, trichloromethyl chloroformate, which is a dimer of phosgene, and bis (trichloromethyl) carbonate, which is a trimer of phosgene, are also included. Furthermore, dihydroxy compounds derived from dihydroxy compounds and carbonyl halide compounds such as 2,2-bis (4'-chlorocarbonyloxyphenyl) propane and 1,2-bis (4'-chlorocarbonyloxyphenyl) ethane. The haloformate derivative of can also be mentioned. In the production method of the present invention, for example, when a carbonyl halide compound is used as the carbonate precursor, the amount thereof is about 1.0 to about 1.3 times the molar amount of the aromatic dihydroxy compound. Is preferred. The carbonate precursor can be used in a gas state, a liquid state, or a solid state, or can be used as an organic solvent solution.

The organic solvent used in the present invention may be any solvent so long as it is substantially inert to water and inert to the reaction and dissolves the aromatic polycarbonate. . For example, aliphatic chlorinated substances such as dichloromethane, chloroform, 1,2-dichloroethane, 1,2-dichloroethylene, trichloroethane, tetrachloroethane and dichloropropane, or chlorinated carbonized substances such as aromatic chlorinated substances such as chlorobenzene and dichlorobenzene. Hydrogen or mixtures thereof can be mentioned as suitable organic solvents. Moreover, you may use the organic solvent which mixed these chlorinated hydrocarbons or those mixtures with aromatic hydrocarbons, such as toluene, xylene, and ethylbenzene, and aliphatic hydrocarbons, such as hexane, heptane, and cyclohexane. A particularly preferred organic solvent is dichloromethane.

The water used in the present invention is distilled water, ion-exchanged water, recovered water produced during the production of aromatic polycarbonate, or a mixture thereof. The amount of water used is usually about 0.5 to about 5 liters per 1 mol of the aromatic dihydroxy compound. When the base aqueous solution of the aromatic dihydroxy compound is prepared, the amount of water used may be the amount necessary to dissolve the aromatic dihydroxy compound and the base or more. For example, when the aromatic dihydroxy compound is bisphenol A, the amount of water is about 0.8 to about 2.2 liters per 1 mol of bisphenol A. The amount of the organic solvent and water used in the reaction may be any amount required to maintain the substantially homogeneous emulsified state of the reaction mixture, usually the volume ratio of the aqueous layer to the organic solvent layer. Is preferably about 0.4 to about 1.5: 1.

The base used in the present invention is preferably an alkali metal or alkaline earth metal base, for example,
Examples thereof include hydroxides of alkali metals or alkaline earth metals such as sodium hydroxide, potassium hydroxide and calcium hydroxide. These bases may be used alone or in combination. The amount of the base used is about 1.0 to 1.6 with respect to the amount of the aromatic dihydroxy compound.
It is preferably double equivalent. The base is usually used in the form of an aqueous solution, and it is preferable to dissolve the aromatic dihydroxy compound in this aqueous solution to prepare a basic aqueous solution of the aromatic dihydroxy compound and use it in the reaction.

In preparing a basic aqueous solution of an aromatic dihydroxy compound, sodium hydrosulfite is added for the purpose of preventing coloration. In the present invention, at this time, 85% by weight or more of sodium hydrosulfite is used. The amount of sodium hydrosulfite added is preferably about 0.01 to about 1.0% by weight, based on the amount of aromatic dihydroxy compound used.
More preferably about 0.03 to about 0.5% by weight.
The addition amount of the sodium hydrosulfite is 0.01
If the amount is less than 10% by weight, the effect of preventing the coloring of the basic aqueous solution of the aromatic dihydroxy compound is not sufficient, and the addition of 1.0% by weight or more does not change the effect of preventing the coloring.

In the production method of the present invention, a polycarbonate-forming catalyst (also called a polymerization catalyst) optionally used is a tertiary amine, a quaternary ammonium salt,
Examples thereof include a tertiary phosphine, a quaternary phosphonium salt, or a nitrogen-containing heterocyclic compound and its salt, imino ether and its salt, and a compound having an amide group. Preferred are tertiary amines such as triethylamine, tri-n-propylamine, diethyl-n-propylamine, tri-n-butylamine, N, N-dimethylcyclohexylamine, N, N-diethylcyclohexylamine, N. -Ethyl piperidine and the like can be mentioned. These polycarbonate-forming catalysts may be used alone or in combination. The amount of the polycarbonate-forming catalyst used is preferably about 0.0005 to about 1.5 mol% based on the number of moles of the aromatic dihydroxy compound.

In the production method of the present invention, it is preferable to use a molecular weight regulator. The molecular weight modifier is a compound having a function of controlling the molecular weight at the time of producing an aromatic polycarbonate, and is generally a monovalent aromatic hydroxy compound, a haloformate derivative of a monovalent aromatic hydroxy compound, a monovalent carboxylic acid. A monovalent carboxylic acid halide derivative or the like is used. Examples of monovalent aromatic hydroxy compounds include phenol, p-cresol, p-ethylphenol, p-tert-butylphenol, p-cumylphenol, p-cyclohexylphenol, p-octylphenol, 2,4-xylenol, p. -Methoxyphenol, p-hexyloxyphenol, p-chlorophenol, p-bromophenol, pentachlorophenol, pentabromophenol, p-phenylphenol, p-isopropenylphenol, 2,4-di (1-methyl-1) -Phenylethyl) phenol, β-
Naphthol, α-naphthol, p- (2 ', 4', 4 '
-Trimethylchromanyl) phenol, 2- (4'-methoxyphenyl) -2- (4 "-hydroxyphenyl)
Phenols such as propane, or their alkali metal salts or alkaline earth metal salts. The haloformate derivative of a monovalent aromatic hydroxy compound is the haloformate derivative of the above monovalent aromatic hydroxy compound.

The monovalent carboxylic acid is, for example, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, heptanoic acid, caprylic acid, 2,2-dimethylpropionic acid, 3-methylbutyric acid, 3,3-dimethylbutyric acid. , 4-methylvaleric acid, 3,
Fatty acids such as 3-dimethylvaleric acid, 2,4-dimethylvaleric acid, 4-methylcaproic acid and phenoxyacetic acid, or their alkali metal salts or alkaline earth metal salts, benzoic acid, p-methylbenzoic acid, p Benzoic acids such as -tert-butylbenzoic acid, p-butoxybenzoic acid, p-hexyloxybenzoic acid, p-octyloxybenzoic acid, p-phenylbenzoic acid and p-chlorobenzoic acid, or alkali metal salts thereof or It is an alkaline earth metal salt. 1
The divalent carboxylic acid halide derivative is, for example, the above monovalent carboxylic acid halide derivative. These may be used alone or in combination. Phenol, p-cumylphenol, or p-tert-butylphenol is particularly preferable.

Aromatic polycarbonates having various molecular weights can be produced by the production method of the present invention, but the produced aromatic polycarbonates have a weight average molecular weight (standard polystyrene conversion value) of about 10,000 to about 1.
What is 00000 is preferable, about 30,000 to about 7
It is more preferably 0000. Weight average molecular weight of aromatic polycarbonate (standard polystyrene equivalent)
Can be controlled by adjusting the amount of the molecular weight regulator used.

In the production method of the present invention, if desired,
A branched aromatic polycarbonate can be produced by adding a branching agent at the time of production. As a branching agent, three or more phenolic hydroxy groups,
Examples thereof include compounds having a haloformate group, a carboxyl group, a carbonyl halide group, and an active halogen atom. Specific examples of the branching agent include 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, α, α, α′-tris (4′-hydroxyphenyl) -1-ethyl-4-isopropylbenzene, tris (4-hydroxyphenyl) phosphine,
1,1,4,4-Tetrakis (4′-hydroxyphenyl) cyclohexane, 3,3 ′, 5,5′-tetrahydroxydiphenyl ether, 3,5-dihydroxybenzoic acid, 4-hydroxyisophthalic acid, 5-hydroxyphthal Acid, trimesic acid trichloride, cyanuric acid chloride and the like can be mentioned. These branching agents are
They may be used alone or in combination.
The amount of the branching agent used can be changed according to the degree of branching of the desired branched aromatic polycarbonate, and is usually about 0.
It is preferable to use about 05 to about 2.0 mol%.

The production method of the present invention is usually carried out at about 10 ° C. to the boiling temperature of the organic solvent used in the reaction. Also,
Usually, it is carried out under atmospheric pressure, but if desired, it may be carried out under pressure or under reduced pressure. The production method of the present invention may be carried out batchwise or continuously. The reactor used in the production method of the present invention is a known reactor such as a tank reactor, a tubular reactor or a packed tower, or a reactor in which these reactors are arbitrarily combined. The production method of the present invention, using these reactors, usually,
It is carried out by mixing the reaction mixture. The mixing may be performed to such an extent that the separation of the organic solvent layer and the water layer is prevented, and is performed to such an extent that the organic solvent layer and the water layer are uniformly mixed. Usually, mixing is performed using a tank-type stirring device, a static mixer, an orifice mixer, or the like. In addition, the mixing does not always have to be a constant condition during the production of the aromatic polycarbonate. For example, after producing a low molecular weight aromatic polycarbonate oligomer, the mixing conditions should be increased and the polycondensation reaction should be performed efficiently. You can also

The reaction mixture containing the aromatic polycarbonate produced by the method of the present invention is then purified by a batch operation or a continuous operation to recover the aromatic polycarbonate. For example, when an aromatic polycarbonate is produced by the interfacial polymerization method, the organic solvent layer containing the aromatic polycarbonate and the aqueous layer are separated, and if necessary, washed with water or a dilute aqueous base solution. Next, neutralization with a dilute aqueous acid solution is performed. The acid used at that time is
Mineral acids such as hydrochloric acid, sulfuric acid and phosphoric acid. Then, it is repeatedly washed with water until substantially no electrolyte is present.
Then, the organic solvent is removed from the solution of the aromatic polycarbonate in an organic solvent by a known method to recover the aromatic polycarbonate. The method for recovering the aromatic polycarbonate is to remove the organic solvent by distillation or steam distillation, add an organic solvent that does not dissolve the aromatic polycarbonate (poor solvent) to the organic solvent solution of the aromatic polycarbonate, and add the aromatic polycarbonate. There is a method of separating the organic solvent from the obtained organic solvent slurry of aromatic polycarbonate by a method such as filtration in a solid state.

More specifically, by distilling off the organic solvent from the organic solvent solution of the aromatic polycarbonate and bringing the organic solvent solution of the aromatic polycarbonate into a saturated state, the aromatic polycarbonate is crystallized and crushed. And then drying to remove the contained organic solvent, heating while removing the organic solvent from the organic solvent solution of the aromatic polycarbonate, and directly pelletizing the aromatic polycarbonate from the molten state, aromatic polycarbonate The method of pulverizing the resulting gel-like material while supplying the organic solvent solution of the above to warm water and removing the organic solvent, adding the poor solvent or non-solvent, and water to the organic solvent solution of the aromatic polycarbonate, Method of obtaining solid aromatic polycarbonate as a water slurry by heating and concentrating, aromatic polycarbonate A method of obtaining an aromatic polycarbonate in a solid state as a water slurry by adding an organic solvent solution of nate to warm water containing powder of aromatic polycarbonate and removing the organic solvent by evaporation, an organic solvent solution of aromatic polycarbonate And the like are supplied into warm water containing the powder of the aromatic polycarbonate and the poor solvent, the organic solvent is removed by evaporation, and the solid state aromatic polycarbonate is obtained as a water slurry.

Specific examples of the poor solvent or non-solvent include aromatic hydrocarbon solvents such as toluene and xylene, pentane, hexane, heptane, octane, cyclohexane,
Aliphatic hydrocarbon solvents such as methylcyclohexane, alcohol solvents such as methanol, ethanol, propanol, butanol, pentanol, hexanol, acetone, methyl ethyl ketone, diethyl ketone, metlisobutyl ketone, ketone solvents such as cyclohexanone, ethyl acetate, Examples thereof include ester solvents such as butyl acetate and amyl acetate. The aromatic polycarbonate produced by the method of the present invention may be a dye, a pigment, a heat stabilizer, an oxidant, by a known method, during or after the production of the aromatic polycarbonate, alone or in a mixture with another polymer. Inhibitor, hydrolysis stabilizer, UV absorber, mold release agent, organic halogen compound, alkali metal sulfonate, glass fiber,
One or more kinds of various additives such as carbon fiber, glass beads, barium sulfate and TiO ₂ may be added.

The aromatic polycarbonate produced by the method of the present invention can be used alone or as a mixture with another polymer as a molding material. Other polymers include polyethylene, polypropylene, polystyrene, ABS resin, polymethylmethacrylate, polytrifluoroethylene, polytetrafluoroethylene, polyacetal, polyphenylene oxide, polybutylene terephthalate, polyethylene terephthalate, polyamide, polyimide, polyamideimide, poly. Examples thereof include ether imide, polysulfone, polyether sulfone, paraoxybenzoyl-based polyester, polyarylate, and polysulfide.

The aromatic polycarbonate produced by the method of the present invention is soluble in a specific organic solvent (for example, a halogenated hydrocarbon solvent such as dichloromethane), and is cast from a solution of the aromatic polycarbonate in an organic solvent. Then, it can be processed into a molded product such as a film. Aromatic polycarbonate produced by the method of the present invention,
Thermoplastic, injection molding, extrusion molding from the melt,
It can be easily molded by a known method such as blow molding or lamination. The aromatic polycarbonate produced by the method of the present invention may be used alone or in a mixture with another polymer, and if desired, various additives may be added to the chassis or housing material of 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, or a building material instead of glass.

[0033]

EXAMPLES The present invention will be described in more detail with reference to examples below, but the present invention is not limited to the following examples. Each characteristic value was measured by the following method.・ Purity of sodium hydrosulfite: JIS K
According to -1476, that is, after dissolving sodium hydrosulfite in a neutral formalin solution, by titrating with an iodine solution using a starch solution as an indicator under hydrochloric acid acidity, the purity of sodium hydrosulfite (% by weight) ) Was asked. -Molecular weight: GPC [gel permeation chromatography, Showa Denko KK, GPC system-11]
Weight average molecular weight (standard polystyrene conversion value)
I asked. Color tone (YI value): A sufficiently dried powder of aromatic polycarbonate was used to prepare a press sheet (thickness: 1 mm) at 280 ° C using a hot press machine. The YI value (yellowness) of the obtained pressed sheet was determined by a transmission measurement method using a color difference meter (manufactured by Suga Test Instruments Co., Ltd.). The smaller the YI value, the smaller the degree of coloring. 5% weight loss temperature: DTA / TG [Thermobalance, manufactured by Shimadzu Corp., DTG-40 series] was used, and the temperature was raised at a rate of 10 ° C / min and the measurement was performed in an air atmosphere.

Example 1 A 10-liter baffled flask was equipped with a three-stage, six-blade stirrer and a reflux condenser. In this flask,
Bisphenol A 912 g (4.0 mol), p-tert-
Butylphenol 20.4 g (0.136 mol, 3.4 mol% based on bisphenol A), dichloromethane 4
1 liter and 4 liters of deionized water were added to make a suspension, and a nitrogen purge was performed to remove oxygen in the flask. Next, 1.2 g of sodium hydrosulfite having a purity of 85.0% by weight (0.13% by weight with respect to bisphenol A) and 436 g of caustic soda were added to the above suspension.
2.2 liter of an aqueous solution containing (10.9 mol) was supplied, and bisphenol A was dissolved at 15 ° C. Then, under stirring, 467 g (4.72 mol) of phosgene was added to this mixture.
For 30 minutes. During this time, the reaction temperature rose to 39 ° C., and reflux of dichloromethane was confirmed. After the introduction of phosgene, 0.32 g of triethylamine (0.08 mol% based on bisphenol A) was added, and the reaction solution was stirred for another 90 minutes to carry out a polymerization reaction. Then, the reaction solution was allowed to stand still, the organic layer 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, and the mixture was heated to 98 ° C. to distill off dichloromethane and toluene to obtain a powder of aromatic polycarbonate. It was The results of measuring the respective characteristic values of the obtained aromatic polycarbonate were as shown in Table 1 (Table 1).

Examples 2 to 4 Instead of using sodium hydrosulfite having a purity of 85.0% by weight in Example 1, the purity was 8%.
7.5 wt% sodium hydrosulfite (Example 2), 90.0 wt% sodium hydrosulfite (Example 3), and 94.5 wt% sodium hydrosulfite (Example 4) An aromatic polycarbonate was produced in the same manner as in Example 1 except that The results of measuring the respective characteristic values of the obtained aromatic polycarbonates are as shown in Table 1.

Comparative Examples 1-2 For comparison, in Example 1, the purity was 85.0% by weight.
Except that sodium hydrosulfite having a purity of 75.0% by weight (Comparative Example 1) and sodium hydrosulfite having a purity of 55.0% by weight (Comparative Example 2) were used in place of the sodium hydrosulfite of Comparative Example 2 Is
An aromatic polycarbonate was produced in the same manner as in Example 1. The results of measuring the respective characteristic values of the obtained aromatic polycarbonates are as shown in Table 1.

[0037]

[Table 1] From the above results, the aromatic polycarbonate produced by the method of the present invention has a lower degree of coloring than the aromatic polycarbonate produced using low-purity sodium hydrosulfite, and is excellent in color tone. ing. Moreover, since the 5% weight loss temperature is not substantially lowered, the heat resistance is also excellent.

[0038]

According to the present invention, color tone and heat resistance (5%
It has become possible to produce an aromatic polycarbonate having an excellent weight loss 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. An aromatic polycarbonate using sodium hydrosulfite having a purity of 85% by weight or more when producing an aromatic polycarbonate from an aromatic dihydroxy compound and a carbonate precursor in the presence of sodium hydrosulfite. Manufacturing method.