JPH0892380A - Method for concentrating aromatic polycarbonate solution - Google Patents

Abstract

(57) [Summary] [Structure] An aromatic polycarbonate organic solvent solution is concentrated under pressure at a temperature higher than the boiling point of the solution under normal pressure,
Method for concentrating an aromatic polycarbonate solution to obtain an aromatic polycarbonate organic solvent solution. [Effect] It is possible to obtain an aromatic polycarbonate organic solvent solution having an arbitrary concentration. In particular, an aromatic polycarbonate organic solvent solution having a concentration of 41% by weight or more, in which the aromatic polycarbonate in the organic solvent solution precipitates and / or the solution gels at a temperature below the boiling point of the solution at atmospheric pressure, which has been heretofore unobtainable Can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for concentrating an aromatic polycarbonate organic solvent solution and a method for producing an aromatic polycarbonate solid.

[0002]

There are various known methods for producing an aromatic polycarbonate in the presence of an organic solvent solution and water, but in any of the methods, the aromatic polycarbonate is organic at the end of the reaction. Obtained as a solvent solution. Aromatic polycarbonate is extruded,
For use in molding such as injection molding and rotation molding,
Even when used as a casting film, a solid state is desirable from the viewpoint of transportation and storage, and therefore it is necessary to concentrate the above solution and take it out as a solid.

Generally, an aromatic polycarbonate is obtained by concentrating and granulating the organic solvent solution with a kneader or a ruder. However, in order to perform concentration and granulation with one apparatus, a large apparatus is required, and it takes a long time, which is industrially disadvantageous. Therefore, many preconcentration methods have been conventionally proposed. For example, JP-A-62-203103
Japanese Patent Laid-Open No. 55-15645, Japanese Patent Laid-Open No. 3-1.
No. 74404, Japanese Patent Laid-Open No. 2-185530 and the like disclose a direct heating method using a plate fin type heat exchanger or a multi-tube heat exchanger. In these methods, since the solvent evaporates inside the heat exchanger, a part of the aromatic polycarbonate is deposited inside the heat exchanger, and the operation is stopped or the flow of the solution becomes irregular and the operation cannot be performed stably. And the like, and it is difficult to obtain an aromatic polycarbonate organic solvent solution concentrated to an arbitrary high concentration. JP-A-5
No. 295102 discloses a method of preventing precipitation of aromatic polycarbonate by pressurizing the inside of a heat exchanger system with an aromatic polycarbonate organic solvent solution head. However, there are problems that it takes a long time to concentrate, concentration distribution is likely to occur, and a film is formed on the liquid surface.

As shown in the above example, the aromatic polycarbonate organic solvent solution has a low thermal conductivity and also becomes highly viscous as it is concentrated, making uniform stirring difficult. for that reason,
There are problems that the solution is easily heated locally, a part of the aromatic polycarbonate is deposited, the concentration distribution is formed, and it is difficult to obtain a solution concentrated to an arbitrary high concentration. Further, since the aromatic polycarbonate organic solvent solution loses fluidity when it reaches the gelling concentration, an aromatic polycarbonate organic solvent solution having a concentration equal to or higher than the gelling concentration under normal pressure can be obtained by any method including the above method. There wasn't.

On the other hand, a method of obtaining a solid by heating and concentrating a low-concentration aromatic polycarbonate organic solvent solution (Japanese Patent Application Laid-Open No. 6-58242).
3-286436, Japanese Patent Laid-Open No. 2-45536, Japanese Patent Publication No. 2-46054, Japanese Patent Publication No. 3-4149.
Various publications have been proposed so far. However, since a low-concentration aromatic polycarbonate organic solvent solution foams violently at a high processing temperature, the liquid level of the solution rises and closes the decompression port or exhaust port of the concentrator. There are problems such as inclusion and low bulk density. In order to avoid these problems, all of the above methods keep the processing temperature low, and as a result require a long processing time, which is not always an industrially satisfactory technique.

Therefore, a method for stably concentrating an aromatic polycarbonate organic solvent solution to an arbitrary concentration, an aromatic polycarbonate organic solvent solution having a small amount of foaming, that is, a high concentration, and an aromatic having a short treatment time are used. A method for solidifying polycarbonate has been desired.

[0007]

Means for Solving the Problems As a result of intensive studies for solving the above-mentioned problems, the present inventors have surprisingly found that the aromatic polycarbonate organic solvent solution is higher than the boiling point of the solution at normal pressure under pressure. By concentrating at high temperature,
Ability to improve the fluidity of the solution and prevent local heating, obtain an aromatic polycarbonate organic solvent solution of any concentration, precipitate aromatic hydrocarbon or gel the solution even if concentrated above the gelling concentration at normal pressure I found that I didn't. Furthermore, the aromatic polycarbonate organic solvent solution concentrated to a high concentration has a small amount of foaming upon heating, and the processing time of various aromatic polycarbonate solid production methods by using the aromatic polycarbonate organic solvent solution concentrated to a high concentration. Can be significantly shortened,
It was found that the aromatic polycarbonate organic solvent solution concentrated to a concentration not lower than the gelling concentration becomes a gel-like substance in a short time when cooled, and the present invention has been completed.

That is, the present invention is obtained by a method for concentrating an aromatic polycarbonate, which comprises concentrating an aromatic polycarbonate organic solvent solution under pressure at a temperature higher than the boiling point of the solution under normal pressure, and the above method. The present invention relates to an aromatic polycarbonate organic solvent solution, and a method for producing an aromatic polycarbonate, which comprises producing an aromatic polycarbonate solid material from the aromatic polycarbonate organic solvent solution.

The present invention will be described in detail below. The aromatic polycarbonates used in the present invention are usually prepared by well known methods, for example from dihydric phenol carbonyl chloride or dihydric phenol bischloroformate.

The dihydric phenol used in the present invention is a compound represented by the general formula (1). HO-R-OH (1) (In the formula, R is a divalent aliphatic or alicyclic residue having 2 to 12, preferably 2 to 6 carbon atoms, or 6
A divalent aromatic group consisting of one or more aromatic nuclei having from 18 carbon atoms, which are either directly bonded to each other or optionally via a divalent bridging member. It means a group. In the present invention, the dihydric phenol is preferably represented by the general formula (2) or (3). HO-Ar1-X-Ar2-OH (2) HO-Ar3-OH (3) (In the formula, Ar1, Ar2, and Ar3 are each a monocyclic unsubstituted or halogen atom, a nitro group, an alkyl group, a cycloalkyl group, A divalent aromatic group having a substituent such as an alkenyl group, an aralkyl group, an aryl group or an alkoxy group,
X is a group that connects Ar1 and Ar2. )

In the above formula, Ar1, Ar2 and A
r3 is a monocyclic divalent aromatic group, that is, a phenylene group or a substituted phenylene group having a substituent, and the substituent is a halogen atom, a nitro group, an alkyl group, a cycloalkyl group, an alkenyl group, or an aralkyl group. Groups, aryl groups, alkoxy groups and the like. Ar1 and Ar2
Both are p-phenylene group, m-phenylene group or o-
It is preferable that one of the phenylene groups is a p-phenylene group and the other is a m-phenylene group or an o-phenylene group, and it is particularly preferable that both Ar1 and Ar2 are p-phenylene groups.

X is a group for connecting Ar1 and Ar2, which is a single bond or a divalent hydrocarbon group, and further -O-,
It may be a group containing an atom other than carbon and hydrogen, such as —S—, —SO—, —SO ₂ — and —CO—. The divalent hydrocarbon group includes a saturated hydrocarbon group, for example, an alkylidene group such as methylene, ethylene, 2,2-propylidene, and cyclohexylidene, but a group substituted with an aryl group is also included. Further, it may be a hydrocarbon group containing an aromatic group or other unsaturated hydrocarbon group.

Specific examples of the dihydric phenol include bis (4-hydroxyphenyl) methane and 1,1-bis (4
′ -Hydroxyphenyl) ethane, 1,2-bis (4 ′)
-Hydroxyphenylethane, bis (4-hydroxyphenyl) phenylmethane, bis (4-hydroxyphenyl) diphenylmethane, bis (4-hydroxyphenyl) -1-naphthylmethane, 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) isobutane, 2,2-bis (4
′ -Hydroxyphenyl) octane, 2,2-bis (3
′ -Methyl-4′-hydroxyphenyl) propane,
2,2-bis (3'-ethyl-4'-hydroxyphenyl) propane, 2,2-bis (3'-n-propyl-4)
′ -Hydroxyphenyl) propane, 2,2-bis (3
′ -Isopropyl-4′-hydroxyphenyl) propane, 2,2-bis (3′-sec-butyl-4′-hydroxyphenyl) propane, 2,2-bis (3′-te)
rt-butyl-4′-hydroxyphenyl) propane,
2,2-bis (3'-cyclohexyl-4'-hydroxyphenyl) propane, 2,2-bis (3'-allyl-
4'-hydroxyphenyl) propane, 2,2-bis (3'-methoxy-4'-hydroxyphenyl) propane, 2,2-bis (3 ', 5'-dimethyl-4'-hydroxyphenyl) propane, 2 , 2-bis (2 ', 3
′, 5 ′, 6′-Tetramethyl-4′-hydroxyphenyl) propane, 2,2- (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 (2 ', 6'-dibromo-3', 5'-dimethyl-4 '
-Hydroxyphenyl) propane, bis (4-hydroxyphenyl) cyanomethane, 1-cyano-3,3-bis (4'-hydroxyphenyl) butane, 2,2-bis (4'-hydroxyphenyl) hexafluoropropane, etc. Bis (hydroxyaryl) alkanes, 1,1-
Bis (4'-hydroxyphenyl) cyclopentane,
1,1-bis (4'-hydroxyphenyl) cyclohexane, 1,1-bis (4'-hydroxyphenyl)-
3,3,5-trimethylcyclohexane, 1,1-bis (4'-hydroxyphenyl) cycloheptane, 2,2
-Bis (hydroxyaryl) cycloalkanes such as bis (4'-hydroxyphenyl) adamantane, 4,4
Bis (hydroxyaryl) ethers such as ′ -dihydroxydiphenyl ether, 4,4′-dihydroxy-3,3′-dimethyldiphenyl ether, ethylene glycol bis (4-hydroxyphenyl) ether, 4,
4'-dihydroxydiphenyl sulfide, 4,4'-
Bis (hydroxyaryl) sulfides such as dihydroxy-3,3′-dimethyldiphenyl sulfide, 4,
4'-dihydroxydiphenyl sulfoxide, 4,4 '
-Bis (hydroxyaryl) sulfoxides such as -dihydroxy-3,3'-dimethyldiphenyl sulfoxide, 4,4'-dihydroxydiphenyl sulfone, 4,
Bis (hydroxyaryl) sulfones such as 4′-dihydroxy-3,3′-dimethyldiphenyl sulfone, bis (4-hydroxyphenyl) ketone, bis (hydroxyaryl) such as bis (4-hydroxy-3-methylphenyl) ketone ) Ketones, and further 6,6'-dihydroxy-3,3,3 ', 3'-tetramethylspiro (bis) indane [spiroindanbisphenol], trans-2,3-bis (4'-hydroxyphenyl) ) -2
-Butene, 9,9-bis (4'-hydroxyphenyl)
Fluorene, 3,3-bis (4'-hydroxyphenyl) -2-butanone, 1,6-bis (4'-hydroxyphenyl) -1,6-hexanedione, 1,1-dichloro-2,2-bis (4'-hydroxyphenyl) ethylene, 1,1-dibromo-2,2-bis (4'-hydroxyphenyl) ethylene, 1,1-dichloro-2,2-bis (5'-phenoxy-4'-hydroxy Phenyl) ethylene, 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 ′
-Dihydroxydiphenyl and the like. In addition to the above dihydric phenols, hydroquinone, resorcin, etc. are also used. You may use these individually or in mixture of 2 or more types. In the present invention, the dihydric phenol particularly preferably used is bisphenol A. Further, bisphenols containing an ester bond, which can be produced by reacting 2 mol of bisphenol A with 1 mol of isophthaloyl chloride or terephthaloyl chloride, are also useful.

In the present invention, the aromatic polycarbonate organic solvent solution means a conventional method for producing an aromatic polycarbonate, that is, an interfacial polymerization method [interscience publishing, "Incyclopedia of Polymer Science and Technology" 10, 710].
(1969), Chemistry and Physics of Polycarbonate "33 (1964) [Inte
rscience Publishing, “Ency
Clopedia of Polymer Science
ce and Technology "10,710
(1969), "Chemistry and Pys.
ics of Polycarbonate "33 (1
964)]], a dihydric phenol is converted into a carbonyl chloride or a bischloroformate composition of a dihydric phenol in the presence of an organic solvent capable of dissolving an aromatic polycarbonate in the presence of a small amount of a molecular weight modifier, and optionally a branching agent. It may be a homopolymer or copolymer solution of an aromatic polycarbonate obtained by reacting with a substance, or a solution obtained by appropriately diluting or concentrating the solution, or a solution prepared by another method.

In the present invention, the organic solvent used as the solvent of the aromatic polycarbonate organic solvent solution can be arbitrarily used as long as it dissolves the aromatic polycarbonate. Among them, dichloromethane, chloroform,
1,2-dichloroethane, 1,2-dichloroethylene,
Chlorinated hydrocarbons such as monochlorobenzene and dichlorobenzene or mixtures thereof are preferred. Dichloromethane, which has a low boiling point and dissolves aromatic polycarbonate well, is particularly preferable. The aromatic polycarbonate organic solvent solution used in the present invention is acetone, ketones such as methyl ethyl ketone, methanol, alcohols such as isopropanol, benzene, aromatics such as toluene, pentane, hexane, aliphatics such as heptane, Nitromethane, acetonitrile, water, etc. may be contained or added appropriately, and further, various additives used for the purpose of modifying the aromatic polycarbonate and the quality of the obtained aromatic polycarbonate are not adversely affected. There is no problem even if the third component is contained or appropriately added.

In the present invention, the aromatic polycarbonate organic solvent solution is concentrated under pressure at a temperature higher than the boiling point of the solution under normal pressure. In the present invention, the pressurizing method is not particularly limited, and for example, pressurization by vapor pressure of a solvent, pressurization by blowing an inert gas, or the like is possible.

In the present invention, the term "pressurized state" means that the pressure in the aromatic polycarbonate organic solvent solution or the evaporator is higher than normal pressure, preferably 2 kg / cm2 or more, more preferably 5 kg / cm2 or more, most preferably 10 kg.
/ Cm2 or more. The boiling point of the solution is raised by applying a pressure, it is possible to heat the aromatic polycarbonate organic solvent solution to a temperature higher than the boiling point of the solution at normal pressure, as a result, to improve the fluidity of the solution,
It is possible to suppress precipitation of aromatic polycarbonate in the solution or gelation of the solution. Here, the normal pressure in the present invention means a pressure when a pressurizing operation is not performed in particular, and includes a state where the pressure is slightly increased by the solution head pressure or the like.

In the present invention, the temperature for concentrating the aromatic polycarbonate organic solvent solution is higher than the boiling point of the solution at normal pressure, preferably 40 ° C. or higher than the boiling point of the solvent at normal pressure, and more preferably the solvent at normal pressure. Above the boiling point of 60 ° C., most preferably above 80 ° C. above the boiling point of the solvent at normal pressure and below the decomposition temperature of the solvent or aromatic polycarbonate. For example, when the solvent is dichloromethane, the temperature of the aromatic polycarbonate-dichloromethane solution is higher than 43 ° C, preferably 80
C. or higher, more preferably 100.degree. C. or higher, and most preferably 120.degree. C. or higher and 150.degree. C. or lower. As the temperature of the aromatic polycarbonate organic solvent solution is higher, the fluidity of the solution is improved, and further, the precipitation of the aromatic polycarbonate in the solution can be suppressed to a high concentration. The method for heating the aromatic polycarbonate organic solvent solution is not particularly limited, and examples thereof include a method of heating by passing a heat medium through the container jacket, a method of heating by a heat exchanger, and a method of contacting or mixing with hot water or steam under pressure. There are a method, a method of passing an inert gas heated under pressure, and the like.

In the present invention, the apparatus for concentrating the aromatic polycarbonate organic solvent solution is not particularly limited as long as it is an apparatus capable of heating the aromatic polycarbonate organic solvent solution under pressure, and may be a batch type or a continuous type. It may be. Examples of devices that can be used include a pressure vessel with a jacket, a pressure resistant centrifugal thin-film evaporator, a pressure vessel with a pressure resistant heat exchanger, a pressure resistant high viscosity reactor, and a pressure resistant horizontal twin-screw kneader. An example of a concentrating device that can be used in the present invention is shown in FIG.
However, the present invention is not limited thereto.

The concentration of the aromatic polycarbonate organic solvent solution obtained by the present invention is arbitrary and can be determined according to its application, but the gelling concentration is 90% by weight or more.
The following concentrations are preferable, for example, when the solvent is dichloromethane, a concentration of 41% by weight or more and 90% by weight or less is preferable. A low aromatic polycarbonate concentration in the solution is industrially disadvantageous, and in order to increase the aromatic polycarbonate concentration in the solution to more than 90% by weight, it is necessary to raise the temperature of the solution extremely, It is not preferable because it may cause decomposition or heat deterioration of the aromatic polycarbonate.

Here, the gelation of a solution means a state in which an aromatic polycarbonate organic solvent solution becomes cloudy and loses fluidity, and this gelled product is a soft or hard but brittle opaque white lump (Japanese Patent Publication No. 36-21033 gazette). Further, the gelling concentration refers to the concentration at which the aromatic polycarbonate in the organic solvent solution precipitates and / or the solution gels at a temperature equal to or lower than the boiling point of the solution at normal pressure. For example, when the solvent is dichloromethane, the aromatic concentration in the solution The group polycarbonate exhibits a concentration of 41% by weight. Since the aromatic polycarbonate exists in a solution in a supersaturated state at a concentration higher than the gelling concentration, the aromatic polycarbonate in the solution remains concentrated even if it is heated even during heating for a long period of time. Tend to precipitate and / or the solution gels.

The aromatic polycarbonate organic solvent solution having an arbitrary concentration and the aromatic polycarbonate organic solvent solution having a concentration higher than the gelling concentration obtained by the present invention can be used in a method for producing an aromatic polycarbonate solid. . For example, as a gelled product that is cooled and gelled under pressure, or as a sticky dough and / or gelled gel that is concentrated and cooled by flashing under reduced pressure, or is flashed under reduced pressure from pores. Any aromatic polycarbonate solid substance as a gelled product that is gelled by concentration and shearing force, or as a gelled product obtained by further standing or cooling or applying shearing force to the rice cake obtained by flashing under reduced pressure. Can be supplied to the manufacturing method.

In the present invention, the method for producing the aromatic polycarbonate solid material is not particularly limited, and any method can be used. INDUSTRIAL APPLICABILITY The present invention relates to a method for producing an aromatic polycarbonate solid, wherein the treatment temperature is improved and the time required for producing the aromatic polycarbonate solid is shortened, the method for producing an aromatic polycarbonate solid, and / or
Or, it brings about effects such as simplification of driving operation at the time of production, increase of treatment amount and the like, and further improvement of quality of the obtained aromatic polycarbonate solid such as improvement of bulk density and reduction of residual solvent amount. .

The present invention may be either batch-wise or continuous, and the concentration and solidification operations can be carried out by one or a plurality of devices. Industrially, continuous concentration and solidification are possible. It is preferable to carry out an operation of granulating (granulating or pelletizing after melting). Further, the aromatic polycarbonate solid matter obtained by the present invention may be subjected to operations such as sieving, pulverization, drying, dry granulation, pelletization by an extruder, etc., if necessary, depending on the production method and purpose of use. is there.

[0025]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to the following examples as long as the gist thereof is not exceeded. The number average molecular weight and the weight average molecular weight in the examples were measured in terms of polystyrene using GPC (gel permeation chromatography). Aromatic Polycarbonate The concentration of aromatic polycarbonate in the organic solvent solution is calculated from the concentration of the solution before concentration and the amount of solvent recovered at the time of concentration, or the aromatic polycarbonate organic solvent solution or its gel-like substance placed in a porcelain dish is dried. It was calculated from the change in weight before and after. The amount of residual solvent in the aromatic polycarbonate solid was calculated from the amount of change in weight of the obtained aromatic polycarbonate powder before and after drying, or quantified by gas chromatography.

Example 1 Bisphenol A was reacted with phosgene in the presence of dichloromethane and sufficiently purified to obtain a number average molecular weight of 20,0.
00, 15.0 wt% aromatic polycarbonate having a weight average molecular weight of 52,000-500 g of a dichloromethane solution was charged in a cylinder nitrogen (secondary pressure 12.5 kg /
cm ² ) and the internal pressure of the autoclave is 12.0 kg / c
while maintaining m ^2, and concentrated under stirring liquid temperature 120 ° C., it was drawn by occasionally pumping a concentrate was concentrated to the concentration. As a result, a dichloromethane solution having an arbitrary concentration up to an aromatic polycarbonate concentration of 77.3% by weight (calculated from the amount of dichloromethane flowing out) was obtained. These liquids maintained fluidity and could be withdrawn by pressure feeding. Note that the extracted liquid was further concentrated at 0.2 to 3.0% by weight because it was flushed by decompression at the outlet of the pipe. Further, when the concentration was further advanced and the aromatic polycarbonate concentration became 83.5% by weight or more, the contents solidified and could not be extracted. That is, under these conditions, it was possible to obtain an aromatic polycarbonate organic solvent solution having an arbitrary concentration, in particular, a gelling concentration which could not be obtained until now and up to about 80% by weight.

Example 2 The internal pressure of the autoclave was 7.0 kg / cm ² , and the liquid temperature was 80.
Example 1 was followed except that the temperature was ° C. As a result, a dichloromethane solution having an arbitrary concentration up to an aromatic polycarbonate concentration of 57.0% by weight was obtained. These liquids maintained fluidity and could be extracted by pressure feeding. Note that the extracted liquid was further concentrated at 0.2 to 3.0% by weight because it was flushed by decompression at the outlet of the pipe. Further, when the concentration was further advanced and the aromatic polycarbonate concentration became 66.6% by weight or more, the contents solidified and could not be extracted. That is, under these conditions, it was possible to obtain an aromatic polycarbonate organic solvent solution having an arbitrary concentration, particularly a gelling concentration which could not be obtained until now and up to about 60% by weight.

Comparative Example 1 The internal pressure of the autoclave was 1.0 kg / cm ² , and the liquid temperature was 42.
Example 1 was followed except that the temperature was ° C. As a result, a dichloromethane solution having an arbitrary concentration up to an aromatic polycarbonate concentration of 38.2% by weight (calculated from the amount of dichloromethane flowing out) was obtained. These liquids maintain fluidity,
It was possible to extract by pressure. The concentration of the extracted liquid was in agreement with the above value. Further, when the concentration was further advanced and the aromatic polycarbonate concentration became 44.8% by weight or more, the contents solidified and could not be extracted.

Example 3 Bisphenol A was reacted with phosgene in the presence of dichloromethane and sufficiently purified to obtain a number average molecular weight of 20,0.
00, 15.0 wt% of an aromatic polycarbonate having a weight average molecular weight of 52,000-500 g of a dichloromethane solution in the apparatus of Example 1 at an autoclave internal pressure of 3.0 kg /
While maintaining at cm ² , the solution was concentrated at a liquid temperature of 80 ° C with stirring to obtain a 53.0 wt% aromatic polycarbonate-dichloromethane solution. This solution was transferred to a Σ type kneader crusher (manufactured by Irie Shokai), which was maintained at a jacket temperature of 30 ° C and an internal pressure of 4.0 kg / cm ² through a pipe that kept warm, and it was kept under pressure 2
The mixture was cooled, kneaded, and ground for 0 minute to obtain an aromatic polycarbonate powder. The obtained aromatic polycarbonate powder is put into a porcelain dish and dried under reduced pressure at 120 Torr at 60 ° C. for 2 hours,
Further, after air-dried at 150 ° C. for 3 hours, the bulk density was measured and found to be 0.65 g / ml.

Comparative Example 2 The internal pressure of the autoclave was 1.0 kg / cm ² , and the liquid temperature was 43.
A solution of 36.0 wt% aromatic polycarbonate in dichloromethane was obtained according to Example 3 except that the temperature was changed to 0 ° C. When this solution was cooled and kneaded for 20 minutes in the same manner as in Example 3, the aromatic polycarbonate did not solidify and a sticky aromatic polycarbonate cake was obtained. 1 more mochi
When it was cooled, kneaded, and ground, an aromatic polycarbonate powder was obtained. The obtained aromatic polycarbonate powder was put into a porcelain dish, dried under reduced pressure at 120 Torr at 60 ° C. for 2 hours, and then air-dried at 150 ° C. for 3 hours, and then the bulk density was measured to be 0.65 g / ml. .

Example 4 Bisphenol A was reacted with phosgene in the presence of dichloromethane and sufficiently purified to obtain a number average molecular weight of 20,0.
00, 15.0 wt% of an aromatic polycarbonate having a weight average molecular weight of 52,000-500 g of a dichloromethane solution in the apparatus of Example 1 at an autoclave internal pressure of 3.0 kg /
While maintaining at cm ² , the solution was concentrated at a liquid temperature of 80 ° C under stirring to obtain a 51.0 wt% aromatic polycarbonate-dichloromethane solution. The liquid was kept warm and was flushed into a Σ type kneader crusher with a jacket temperature of 40 ° C and an internal pressure of 1.0 kg / cm ² and 200 g of nitrogen gas at 20 to 25 ° C.
The mixture was concentrated, kneaded and pulverized for 10 minutes while ventilating at a flow rate of / h to obtain an aromatic polycarbonate powder. The obtained aromatic polycarbonate powder is put into a porcelain dish and kept at 60 ° C. for 2 hours 12
It was dried under reduced pressure at 0 Torr and further dried under ventilation at 150 ° C. for 3 hours, and then the bulk density was measured to be 0.63 g / ml.
Met.

Comparative Example 3 The internal pressure of the autoclave was 1.0 kg / cm ² , and the liquid temperature was 43.
A solution of 36.0% by weight of aromatic polycarbonate-dichloromethane was obtained according to Example 4 except that the temperature was changed to 0 ° C. When this solution was concentrated and kneaded for 10 minutes in the same manner as in Example 4, the aromatic polycarbonate did not solidify, and a sticky aromatic polycarbonate cake was obtained. 2 more rice cakes
When the mixture was concentrated, kneaded and ground for 0 minute, an aromatic polycarbonate powder was obtained. The obtained aromatic polycarbonate powder was put in a porcelain dish, dried under reduced pressure at 120 Torr at 60 ° C. for 2 hours, and then air-dried at 150 ° C. for 3 hours, and then the bulk density was measured to be 0.64 g / ml. .

Example 5 Bisphenol A was reacted with phosgene in the presence of dichloromethane and sufficiently purified to obtain a number average molecular weight of 20,0.
00, 15 wt% of aromatic polycarbonate having a weight average molecular weight of 52,000-100 kg of dichloromethane solution in a pressure-resistant container with a jacket having an inner volume of 0.2 m ³ and an internal pressure of 1
The mixture was concentrated at a liquid temperature of 120 ° C. with stirring at 0.0 kg / cm ² , to obtain a 66.0 wt% aromatic polycarbonate-dichloromethane solution. This solution is used to pump 120
Through a jacketed pipe through which a heat medium of ℃ was passed, the dies were removed and flushed into the hopper of a ventless twin-screw extruder (Toyo Seiki Seisakusho, Labo Plastomill, model 30R150) and kneading and extruding without heating. Thus, 2.6 kg / h of a soft aromatic polycarbonate powder was obtained. Part of the obtained aromatic polycarbonate powder was put in a porcelain dish, dried under reduced pressure at 120 Torr at 60 ° C. for 2 hours, and then air-dried at 150 ° C. for 3 hours, and then the bulk density was measured to be 0.65 g / ml. Met.

Comparative Example 4 At the time of concentration, the internal pressure of the container was 1.0 kg / cm ² , and the liquid temperature was 40 ° C.
A aromatic polycarbonate 36.0 wt% -dichloromethane solution was obtained according to Example 5 except that When this solution was kneaded and extruded in the same manner as in Example 5, the aromatic polycarbonate did not solidify and a sticky aromatic polycarbonate cake was obtained.

Example 6 Bisphenol A was reacted with phosgene in the presence of dichloromethane and sufficiently purified to obtain a number average molecular weight of 20,0.
00, 15 wt% aromatic polycarbonate having a weight average molecular weight of 52,000-100 kg of dichloromethane solution was concentrated in a pressure-resistant container with a jacket having an inner volume of 0.2 m ³ at an internal pressure of 4.0 kg / cm ² and a liquid temperature of 60 ° C. under stirring. Then, a 45.0 wt% aromatic polycarbonate-dichloromethane solution was obtained. This solution is 120 ° C with a plunger pump.
Kneader (Kurimoto Iron Works Co., Ltd., SC Processor, model SCP-10
The hopper of 0) was continuously flushed and kneaded while being concentrated at a jacket temperature of 70 ° C. and a stirring rate of 20 rpm. By adjusting the supply amount, an aromatic polycarbonate powdery substance having a maximum of 10.3 kg / h was obtained. A part of the obtained aromatic polycarbonate powder was put into a porcelain dish, dried under reduced pressure at 120 Torr at 60 ° C. for 2 hours, and then air-dried at 150 ° C. for 3 hours, and then the bulk density was measured.
It was 0.57 g / ml.

Comparative Example 5 At the time of concentration, the internal pressure of the container was 1.0 kg / cm ² , and the liquid temperature was 40 ° C.
Aromatic polycarbonate 32.5 wt% -dichloromethane solution was obtained according to Example 6 except that This solution was kneaded according to Example 6 while concentrating it at a jacket temperature of 70 ° C. and a stirring rate of 20 rpm. By controlling the supply amount, a maximum of 5.8 kg / h of aromatic polycarbonate powder was obtained. When the amount supplied was more than this, the aromatic polycarbonate did not solidify and became a sticky dough.

Example 7 Bisphenol A was reacted with phosgene in the presence of dichloromethane and sufficiently purified to obtain a number average molecular weight of 18,0.
00, 15 wt% aromatic polycarbonate having a weight average molecular weight of 47,000-100 kg of dichloromethane solution in a pressure resistant container with a jacket having an inner volume of 0.2 m ³ and an internal pressure of 1
The mixture was concentrated at 0.0 kg / cm ² and a liquid temperature of 120 ° C. with stirring to obtain a 70.0 wt% aromatic polycarbonate-dichloromethane solution. This solution is used to pump 120
It is continuously supplied to a thin film evaporator (manufactured by Hitachi, Ltd., vertical tilted blade controller, heat transfer area 0.16 m ² ) decompressed by a vacuum pump through a jacketed pipe through which a heating medium of ℃ is passed.
Concentration and melting were performed at a jacket temperature of 280 ° C. When the solution supply rate was adjusted so that the molten aromatic polycarbonate acquisition rate was 5.0 kg / h, the internal pressure of the evaporator during stable operation was 120 Torr, and the residual dichloromethane amount in the obtained aromatic polycarbonate was 200 ppm.
Met.

Comparative Example 6 The pressure inside the container at the time of concentration was 1.0 kg / cm ² , and the liquid temperature was 40 ° C.
According to Example 7 except that the above, an aromatic polycarbonate 30.4 wt% -dichloromethane solution was obtained. This solution was concentrated and melted according to Example 7. When the solution supply rate was adjusted so that the molten aromatic polycarbonate acquisition rate was 5.0 kg / h, the evaporator internal pressure during stable operation was 7
It was 60 Torr, and the amount of residual dichloromethane in the obtained aromatic polycarbonate was 3500 ppm.

Example 8 Bisphenol A was reacted with phosgene in the presence of dichloromethane and sufficiently purified to obtain a number average molecular weight of 18,0.
00, 15 wt% aromatic polycarbonate having a weight average molecular weight of 47,000-100 kg of dichloromethane solution in a pressure resistant container with a jacket having an inner volume of 0.2 m ³ and an internal pressure of 1
The solution was concentrated at a liquid temperature of 150 ° C. with stirring at 4.0 kg / cm ² , to obtain 87.0 wt% aromatic polycarbonate-dichloromethane solution. This solution is supplied by a plunger pump to 150
Through a pipe with a jacket through which a heating medium of ℃ is passed, the hopper of a kneading extruder with 5 vents (KTX-46, manufactured by Kobe Steel Ltd.) is continuously flushed, and kneading and extruding at 280 ° C. under reduced pressure 40 kg / h of aromatic polycarbonate pellets were obtained.

Comparative Example 7 The pressure inside the container at the time of concentration was 1.0 kg / cm ² , and the liquid temperature was 40 ° C.
Aromatic polycarbonate 34.1 wt% -dichloromethane solution was obtained according to Example 8 except that When this solution was kneaded and extruded under reduced pressure according to Example 8, the aromatic polycarbonate dichloromethane solution vigorously foamed in the extruder and flowed out to the vent portion, and the vent portion was blocked, so that the operation was impossible.

Example 9 An aromatic polycarbonate powder was produced using the apparatus shown in FIG. Here, as the aromatic polycarbonate-dichloromethane solution, bisphenol A was reacted with phosgene in the presence of dichloromethane and sufficiently purified to obtain a number average molecular weight of 20,000 and a weight average molecular weight of 48.0.
A 20.0 wt% aromatic polycarbonate-dichloromethane solution of 00 was used. The above aromatic polycarbonate 2
25 kg / h of 0 wt% -dichloromethane solution was supplied to a thin film evaporator and concentrated under pressure heating to obtain 50 wt% of aromatic polycarbonate-dichloromethane solution 10
kg / h was obtained. The thin film evaporator has a heat transfer area of 0.
Use a pressure resistant thin film evaporator with a jacket of 38m ² (Hievarator made by Sakura Seisakusho), and use a jacket at 80 ℃.
The internal pressure was maintained at 4.1 kg / cm ² by passing a nitrogen gas under pressure through the heating medium. A 50% by weight aromatic polycarbonate-dichloromethane solution discharged from the thin film evaporator was supplied by a plunger pump through a jacketed pipe through which a heating medium at 80 ° C was passed into the granulation tank through pores with a diameter of 1.0 mm. did. As a granulation tank, a 0.1 m ³ jacketed stirring tank equipped with a stirrer with paddle blades was used, and the temperature of the water slurry in the granulation tank was kept at 50 ° C. by hot water flowing through the jacket, and dichloromethane was added under normal pressure. Was evaporated. 4.3 m ³ / h of water slurry in the granulation tank was extracted from the granulation tank, pulverized by a wet pulverizer (pipeline homomixer manufactured by Tokushu Kika Kogyo Co., Ltd.), and 100 kg / h was extracted as a product, The rest was returned to the granulation tank. Also, the amount of water slurry in the granulation tank is 40k.
g, 94 kg / h of make-up water was supplied to the granulation tank in order to maintain the concentration of the aromatic polycarbonate powder in the water slurry at 5% by weight. The temperature of the water slurry extracted as a product was raised to 80 ° C., dichloromethane was evaporated, and filtration and 140
Bulk density 0.56g / ml by drying at 6 ℃ for 6 hours
As a result, 5 kg / h of aromatic polycarbonate powder was obtained. The average residence time of the powder in the water slurry was 24 minutes.

Comparative Example 8 In Example 1, hot water of 50 ° C. was passed through the jacket portion of the thin film evaporator, and the inside of the thin film evaporator was kept at normal pressure.
7 kg / h was obtained, and the concentrate was supplied into the granulation tank through a pipe with a jacket through which warm water of 50 ° C. was passed and a diameter of 1.0 mm. 80 kg of water slurry in the granulation tank
Aromatic polycarbonate powder was produced according to Example 9 except that the aromatic polycarbonate-dichloromethane cake was attached to the inside of the stirring blade, the wet pulverizer, the pipe, etc., and the granulation tank was used. Aggregates were formed in the water slurry inside, and operation was impossible.

[0043]

According to the present invention, it is possible to obtain an aromatic polycarbonate organic solvent solution having an arbitrary concentration. In particular, aromatic polycarbonate in an organic solvent solution precipitates and / or the solution gels at a temperature below the boiling point of the solution at atmospheric pressure, which has been heretofore unobtainable. 41
It is possible to obtain an aromatic polycarbonate organic solvent solution having a concentration of not less than wt%. Furthermore, the aromatic polycarbonate organic solvent solution concentrated to an arbitrary concentration and the aromatic polycarbonate in a concentration higher than the concentration at which the aromatic polycarbonate in the organic solvent solution precipitates or the solution gels at a temperature below the boiling point of the solution under normal pressure. The polycarbonate organic solvent solution can be used in any method for producing an aromatic polycarbonate solid, and without changing the conventional production facilities for the aromatic polycarbonate solid, the processing temperature during the production of the aromatic polycarbonate solid can be increased. It is possible to improve and shorten the required time, simplify the production method of aromatic polycarbonate solids and / or the operation during production, increase the throughput, improve the quality of aromatic polycarbonate solids, etc. Is exceptional.

[Brief description of drawings]

FIG. 1 is a schematic diagram of a concentrating device that can be used in the present invention.

FIG. 2 is a schematic diagram of a concentrating device that can be used in the present invention.

FIG. 3 is a schematic diagram of a concentrating device that can be used in the present invention.

FIG. 4 is a schematic diagram of the concentrating device used in Example 1.

FIG. 5 is a schematic diagram of a concentrating device used in Example 9.

[Explanation of symbols]

11 Polycarbonate Organic Solvent Solution 12 Inert Gas for Pressurization 13 Pressure Vessel with Jacket and Stirrer 14 Concentrated Liquid 15 Recovery Solvent 16 Condenser 17 Exhaust System 21 Polycarbonate Organic Solvent Solution 22 Inert Gas for Press 23 Thin Film Evaporator 24 Concentrated Liquid 25 Recovery Solvent 26 Condenser 27 Exhaust system 31 Polycarbonate organic solvent solution 32 Inert gas for pressurization 33 Pressure vessel with jacket and agitator 34 Pump 35 Heat exchanger 36 Concentrated liquid 37 Collected solvent 38 Condenser 39 Exhaust system 41 Pressurizing nitrogen gas 42 Autoclave 43 Electric furnace 44 Concentrated liquid 45 Recovery solvent 46 Condenser 47 Exhaust system 51 Low-concentration aromatic polycarbonate-dichloromethane solution 52 Thin film evaporator 53 Granulating tank 54 Wet grinder 55 Aromatic polycarbonate powder-containing material Slurry (product) 56 dichloromethane 57 makeup water 58 pressurizing the nitrogen gas 59 dichloromethane - Nitrogen Gas

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shoji Obuchi 30 Asamu-cho, Omuta City, Fukuoka Prefecture Mitsui Toatsu Chemical Co., Ltd. (72) Masahiro Ota 30 Asamu-cho, Omuta City, Fukuoka Mitsui Toatsu Inside Chemical Co., Ltd.

Claims (7)

[Claims] 1. A method for concentrating an aromatic polycarbonate solution, which comprises concentrating an aromatic polycarbonate organic solvent solution under pressure at a temperature higher than the boiling point of the solution under normal pressure to obtain an aromatic polycarbonate organic solvent solution. 2. The aromatic polycarbonate organic solvent solution is concentrated under pressure at a temperature higher than the boiling point of the solution under normal pressure to obtain an aromatic polycarbonate organic solvent solution having a concentration not lower than the gelation concentration. Method for concentrating polycarbonate solution. 3. The aromatic polycarbonate organic solvent solution is concentrated at a temperature higher than the boiling point of the solution under atmospheric pressure at a pressure of at least 5.0 kg / cm ² , and the aromatic polycarbonate organic solvent has a concentration not lower than the gelling concentration. A method for concentrating an aromatic polycarbonate solution, which comprises obtaining a solvent solution. 4. An aromatic polycarbonate-dichloromethane solution is concentrated under pressure at a temperature of 60 ° C. or higher and 150 ° C. or lower to obtain an aromatic polycarbonate-dichloromethane solution having a concentration of 41% by weight or more of aromatic polycarbonate in the solution. A method for concentrating an aromatic polycarbonate solution, which comprises: 5. An aromatic polycarbonate organic solvent solution having a gelling concentration or higher. 6. An aromatic polycarbonate-dichloromethane solution having a concentration of 41% by weight or more of aromatic polycarbonate. 7. Claim 1 or claim 2 or claim 3.
Alternatively, an aromatic polycarbonate solid material is produced from the aromatic polycarbonate organic solvent solution obtained by the method according to claim 4, and a method for producing an aromatic polycarbonate.