JPH08269187A - Production of aromatic polycarbonate powder - Google Patents

Abstract

PURPOSE: To obtain the aromatic polycarbonate powder high in bulk density in an extremely short time, namely in a high treating ability, without using a special device. CONSTITUTION: In a method for producing the powder of an aromatic polycarbonate from an aromatic polycarbonate-dichloromethane solution obtained by an interfacial polymerization method, the improvement comprises feeding the aromatic polycarbonatedichloromethane solution having a polymer concentration of 40-90wt.% and a water content of <=500ppm and obtained by concentrating the polymerization solution in a pressed state at a temperature of 45-150 deg.C into a device having a kneading mechanism, concentrating the fed aromatic polycarbonatedichloromethane solution at a temperature below its boiling point, and simultaneously grinding the deposits to obtain the powder of the aromatic polycarbonate.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing an aromatic polycarbonate powder.

[0002]

There are various known methods for producing an aromatic polycarbonate in the presence of dichloromethane and water. In either method, the aromatic polycarbonate is treated as a dichloromethane solution at the end of the reaction. can get. Aromatic polycarbonate is preferably used in molding such as extrusion molding, injection molding, rotational molding, etc., and also as a casting film in the form of a powder from the viewpoint of its transportation and storage surfaces. Need to be collected. There are many proposals for this recovery method.

The first method is aromatic polycarbonate-
This is a so-called poor solvent precipitation method, in which a poor solvent such as alcohols and ketones is mixed with a dichloromethane solution to precipitate and recover the aromatic polycarbonate (Japanese Patent Publication No. 36-224).
47, Japanese Patent Publication No. 36-22448, Japanese Patent Publication No. 3
7-7000, Japanese Patent Publication No. 38-16347).

The second method is aromatic polycarbonate-
This is a so-called atomization method in which a dichloromethane solution is jetted into hot water, steam or hot air to obtain a solid (Japanese Patent Publication No. 36-11231, Japanese Patent Publication No. 40-3533, and Japanese Patent Publication No. 409843). ).

The third method is an aromatic polycarbonate-
This is a so-called gelation method in which a dichloromethane solution is concentrated to obtain a hard but fragile gel-like substance, which is crushed (Japanese Patent Publication No. 36-21033, Japanese Patent Publication No. 44-11031, and Japanese Patent Publication No. 45-9875). ).

Of these methods, the first method uses two or more kinds of solvents, and therefore requires a distillation operation when reusing the recovered solvent, which is industrially disadvantageous.
Further, the second method is disadvantageous in handling because the solid density of the obtained solid is low. Therefore, the third gelling method, which has a high bulk density of the obtained solid and is easy to operate, is excellent.

As a method for obtaining an aromatic polycarbonate solid substance by a gelation method, for example, a dichloromethane solution of an aromatic polycarbonate is concentrated in hot water and pulverized when it becomes a gel (Japanese Patent Publication No. 9875/1985). Japanese Patent Publication No. 3-34492, Japanese Patent Laid-Open No. 2-455.
No. 36) is proposed. However, in the above method, it is necessary to strictly control the concentration and concentrate for a long time in order to obtain a gelled product, and further, the aromatic polycarbonate-dichloromethane solution and the gel thereof are placed in an expensive stirrer for a highly viscous material. It is industrially disadvantageous because it is necessary to retain the substance for a long time.

In order to improve productivity, various special devices for crushing amorphous hard solids have also been proposed (Japanese Patent Publication No. 3-33729, Japanese Patent Publication No. 54-44312, and Japanese Patent Laid-Open No. 62-62). However, these special devices are expensive and industrially disadvantageous. Therefore, there has been a need for a method for industrially producing an aromatic polycarbonate powder in a short residence time without using a special device.

[0009]

Means for Solving the Problems As a result of intensive studies for solving the above-mentioned problems, the present inventors have surprisingly found that an aromatic polycarbonate-dichloromethane solution obtained by an interfacial polymerization method has a pressure of 45%. Aromatic polycarbonate-dichloromethane solution having a polymer concentration of 40% by weight or more, which could not be obtained stably, can be obtained by concentrating at a temperature of ~ 150 ° C, the polymer concentration is high, and the water content is specified. An aromatic polycarbonate-dichloromethane solution adjusted to an amount not more than the amount is concentrated at a temperature not higher than the boiling point of the aromatic polycarbonate-dichloromethane solution to give a very soft gel-like substance that can be crushed with a finger in an extremely short time. Is obtained, and further, by crushing this gel-like material, a special device can be used. Without it found that aromatic polycarbonate powder shaped body is obtained, and have completed the present invention.

That is, the present invention is a method for producing an aromatic polycarbonate powder from an aromatic polycarbonate-dichloromethane solution obtained by an interfacial polymerization method, wherein the polymer concentration in the solution is 40% by weight or more, and ,
Aromatic polycarbonate with a water content of 500 ppm or less-
An aromatic polycarbonate powder is obtained by pulverizing the precipitate while concentrating the dichloromethane solution at a temperature below the boiling point of the solution in an apparatus having a kneading mechanism, with an extremely short residence time, that is, high processing capacity. It is a method for producing an aromatic polycarbonate powder.

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 having 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-dichloromethane solution refers to a conventional method for producing an aromatic polycarbonate, that is, an interfacial polymerization method [interscience publishing, "in-cyclopydia solution".
Polymer Science and Technology "10,
710 (1969), Chemistry and Physics of Aromatic Polycarbonate "33 (196)
4) [Interscience Publishing
ng, "Encyclopedia of Polym
er Science and Technology
y ”10,710 (1969),“ Chemistry
and Physics of Polycarbon
ate "33 (1964)]], reacting a dihydric phenol with a carbonyl chloride or a bischloroformate composition of a dihydric phenol in the presence of dichloromethane, using a small amount of a molecular weight regulator and optionally a branching agent. The homopolymer or copolymer solution of the aromatic polycarbonate obtained by the above process, or a solution obtained by appropriately diluting or concentrating the solution may be used, or a solution prepared by another method may be used.

Dichloromethane used as a solvent in the present invention is 10% by weight or less of another solvent such as chloroform, carbon tetrachloride, 1,2-dichloroethane, 1,2.
-Dichloroethylene, 1,1,2-trichloroethane,
It may contain tetrachloroethane, monochlorobenzene, dichlorobenzene and the like.

Since the aromatic polycarbonate-dichloromethane solution obtained by the interfacial polymerization method contains an organic salt and / or an inorganic salt, it is desirable to perform sufficient purification before it is supplied to an apparatus having a concentration operation or a kneading mechanism.

In the present invention, the amount of water in the aromatic polycarbonate-dichloromethane solution supplied into the apparatus having a kneading mechanism is 500 ppm or less, preferably 200 p.
It is pm or less. When the amount of water in the solution exceeds 500 ppm, the time required for granulation is long, which is not industrially disadvantageous, and the particle size of the obtained powder is large and the bulk density is lowered, which is preferable. Absent. The aromatic polycarbonate-dichloromethane solution obtained by the interfacial polymerization method and the subsequent purification step usually contains several thousand to tens of thousands of pp.
Even if a sufficient amount of liquid separation operation is performed, it is impossible to make the amount of water in the solution not more than the solubility thereof.

Therefore, the aromatic polycarbonate-dichloromethane solution used in the present invention needs to be dehydrated in advance. In the present invention, the amount of water in the aromatic polycarbonate-dichloromethane solution is set to 5
There is no particular limitation on the method for adjusting the content to 00 ppm or less, and examples thereof include a method of dehydrating using molecular sieves, a method of diluting with a dehydrated organic solvent, and a method of dehydrating by azeotropic distillation of water and an organic solvent. Particularly, an industrially advantageous azeotropic dehydration method is preferable.

In the present invention, the concentration of the polymer in the aromatic polycarbonate-dichloromethane solution fed into the apparatus having a kneading mechanism is 40 to 90% by weight, preferably 5%.
It is 5 to 80% by weight. When the polymer concentration is lower than this range, a long residence time is required for the evaporation of dichloromethane, which lowers the treatment capacity, which is not preferable. Further, in order to obtain an aromatic polycarbonate-dichloromethane solution having a polymer concentration higher than this range, it is necessary to make the solution temperature at the time of concentration extremely high, and at such a temperature, dichloromethane is decomposed, which is not preferable.

The aromatic polycarbonate-dichloromethane solution having a polymer concentration of 40 to 90% by weight is the aromatic polycarbonate-dichloromethane solution under pressure at 45 to 15
It can be obtained by concentrating at a temperature of 0 ° C. The pressurizing method is not particularly specified, and, for example, pressurizing by vapor pressure of the solvent or pressurizing by blowing an inert gas can be performed.

The pressurized state means that the pressure in the aromatic polycarbonate-dichloromethane solution and / or the evaporator is higher than normal pressure, preferably 2 kg / cm ² or more, more preferably 5 kg / cm ² or more, most preferably 10 kg / cm ² or more.
It is at least kg / cm ² . The boiling point of the solution is raised by the pressurized state, it is possible to heat the aromatic polycarbonate-dichloromethane 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.

The normal pressure in the present invention means a pressure when no pressurizing operation is performed. The solution temperature at the time of concentration is 45 to 150 ° C, preferably 80 to 150 ° C, more preferably 100 to 150 ° C, and most preferably 120 to 15 ° C.
0 ° C. As the temperature of the aromatic polycarbonate-dichloromethane 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. However, the temperature of the solution is 1
When the temperature exceeds 50 ° C, the solvent dichloromethane is decomposed, which is not preferable.

The method for heating the aromatic polycarbonate-dichloromethane solution is not particularly limited, and examples thereof include a method of heating by passing a heat medium through the jacket of the container, a method of heating by a heat exchanger, and a method of contacting or mixing with hot water or steam. There is a method of ventilating a heated inert gas.

The apparatus for concentrating the aromatic polycarbonate-dichloromethane solution is not particularly limited as long as it can heat the aromatic polycarbonate-dichloromethane solution under pressure, and may be a batch type or a continuous type. . 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.

The aromatic polycarbonate-dichloromethane solution having a polymer concentration of 40% by weight or more is thickened even if it is heated even when it is heated, when it is concentrated or stored for a long time, and it is solid. Therefore, it is preferable to concentrate the aromatic polycarbonate in a short time and rapidly supply it to an apparatus having a kneading mechanism.

In the present invention, the aromatic polycarbonate-dichloromethane solution is under pressure at 45 to 150 ° C.
It is fed into an apparatus having a kneading mechanism while being kept at the temperature of. Since the aromatic polycarbonate-dichloromethane solution having a polymer concentration of 40% by weight or more thickens or gels as the temperature decreases, stable supply becomes difficult unless the temperature is maintained. Further, when the solution is supplied through the pores, crystallization is promoted because the aromatic polycarbonate-dichloromethane solution is subjected to strong shearing force,
The time required for gelation is shortened, and the residence time in an apparatus having a kneading mechanism can be further shortened.

The apparatus having a kneading mechanism in the present invention is not particularly limited as long as it can knead an aromatic polycarbonate-dichloromethane solution having a high concentration and a high solution viscosity, and a conventionally known one can be used. Since the gelled product of the aromatic polycarbonate-dichloromethane solution obtained in the process of the present invention has such hardness that it can be easily crushed with fingers,
The device used does not require a special crushing mechanism or a particularly large shear force or torque. The conventionally known ones include, for example, a kneader, a ruder, an internal mixer, a double planetary mixer, a crusher, a kneader extractor, K.K. R. C. Equipment such as a kneader, taper roll mill, and plastomill. When the present invention is used as a continuous process, it is more desirable to use a self-cleaning type kneader. A kneading machine with a self-cleaning type kneading machine, in which specially shaped paddles are arranged on two shafts that rotate in the same or different directions in a phase with a certain relationship, and the side surfaces of the mating paddles are scraped off from each other. The paddle shape and the phase thereof are, for example, U.S. Pat. Nos. 3,195,865 and 3,198,491, JP-B-60-54974, and JP-A-56-598.
24, JP-A-60-239211 and JP-A-60-1.
No. 01108, etc.

As the apparatus having a kneading mechanism in the present invention, the apparatus described in the above-mentioned patent publication, and further, KRC kneader manufactured by Kurimoto Iron Works, KEX extruder, SC processor, KRC-VP, eyeglass wing polymerization machine manufactured by Hitachi, Mitsubishi A twin-screw kneader represented by a heavy industry SCR reactor can also be used.

The stirring speed at the time of stirring and kneading in the present invention is not particularly limited, but it is desirable that the stirring speed is as high as possible. A high-concentration aromatic polycarbonate-dichloromethane solution forms a film on the surface of the solution in a very short time and inhibits the evaporation of dichloromethane. Therefore, in order to concentrate and gelate the solution in a short time, the solution surface should be rapidly updated. is necessary. The time required for gelation of a solution having a polymer concentration of 40% by weight or more depends on the liquid surface area, but it is usually reduced to about one half by doubling the stirring number.

The temperature below the boiling point of the solution in the present invention is a temperature at which bubbles are not generated in the aromatic polycarbonate-dichloromethane solution, and is usually several degrees higher than the boiling point of dichloromethane. The present invention is usually carried out under atmospheric pressure, but it is also possible to carry out under pressure or reduced pressure,
The temperature below the boiling point in this case is the temperature at which bubbles do not occur in the aromatic polycarbonate-dichloromethane solution under the pressure used. In particular, when the present invention is carried out under pressure, the viscosity of the aromatic polycarbonate-dichloromethane solution is lowered, so that the stirring and kneading becomes easier.

In the present invention, it is preferable to pass an inert gas having a temperature not higher than the boiling point of the solution through the surface and / or the liquid of the dichloromethane solution. The inert gas used in the present invention is a gas which is inert to air, nitrogen, argon, carbon dioxide, oxygen, hydrogen and the like, aromatic polycarbonate and the organic solvent used, and air or nitrogen is industrially preferable. By performing the aeration operation, the removal of the solvent from the aromatic polycarbonate-dichloromethane solution is promoted, and further, the heat of vaporization of the organic solvent cools the aromatic polycarbonate-dichloromethane solution to accelerate the gelation. However, when a remarkably vigorous aeration operation is performed or when a gas having a temperature higher than the boiling point of the solution is used, the surface of the liquid and the gelled product is locally dried, and the bulk density of the obtained aromatic polycarbonate powder decreases. Tend.

The amount of residual solvent in the aromatic polycarbonate powder obtained by the present invention is preferably 35 to 10% by weight. When the residual solvent amount is 35% by weight or more, the obtained aromatic polycarbonate powder may be solidified into a lump. Further, it takes a long time to reduce the residual solvent amount to less than 10% by weight, which is industrially disadvantageous. Furthermore, the amount of residual solvent in the obtained aromatic polycarbonate powder is 1
When it is 0% by weight or more, since the powdery material is not so hardened, the material hardly wears, and a device having a kneading mechanism, such as stainless steel, does not have such high wear resistance. Can be used.

Since many solvents remain in the aromatic polycarbonate powder obtained by the present invention, it is desirable to carry out a drying operation or pelletize with a vented extruder. Further, if necessary, the obtained powdery material may be subjected to sieving, pulverizing operation, dry granulation operation, etc. depending on the purpose.

In the present invention, the additive used for the aromatic polycarbonate can be added to the gelled product of the aromatic polycarbonate-dichloromethane solution and / or the aromatic polycarbonate-dichloromethane solution at any time. Additives are aromatic polycarbonate-dichloromethane solution and / or aromatic polycarbonate-
By adding it to the gelled product of the dichloromethane solution, it becomes possible to uniformly disperse the additive in the powder. Further, when an additive that improves the thermal stability of the aromatic polycarbonate is used, it is possible to suppress the deterioration of the color tone of the aromatic polycarbonate during the drying process.

The present invention may be of a batch type or a continuous type, and industrially it is preferable to continuously perform dehydration, concentration, kneading and pulverization.

[0038]

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). The amount of water in the aromatic polycarbonate-dichloromethane solution was quantified with a Karl Fischer moisture meter.
The concentration of the aromatic polycarbonate in the aromatic polycarbonate-dichloromethane solution was calculated from the weight change amount before and after the drying of the aromatic polycarbonate-dichloromethane solution placed in a porcelain dish. The amount of residual solvent in the aromatic polycarbonate powder 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 1 280 g of bisphenol A, 6.34 g of p-tert-butylphenol, 0.56 g of sodium hydrosulfite and 143 g of sodium hydroxide were dissolved in 1600 g of water, and phosgene was stirred with mixing the aqueous solution and 2080 g of dichloromethane. 145.6 g was fed over 1 hour. Then, 0.5 g of triethylamine, which is a polymerization catalyst, was added to the mixed solution, and the mixture was aged for 2 hours, the reaction solution was allowed to stand still, and a dichloromethane solution of aromatic polycarbonate was separated. A dichloromethane solution of this aromatic polycarbonate was mixed with 1 liter of a 0.1 N hydrochloric acid aqueous solution, and the mixture was stirred until a sufficient emulsified state was obtained to carry out a neutralization treatment. Then, the organic phase was again separated by static separation, mixed with 1 liter of pure water, stirred in the same manner, and washed with water. This water washing treatment was repeated until the organic phase was substantially free of salt. The organic phase that had been washed and purified with water was filtered to obtain a 15 wt% aromatic polycarbonate-dichloromethane solution having a number average molecular weight of 20,000 and a weight average molecular weight of 52400.
The amount of water in the obtained aromatic polycarbonate-dichloromethane solution was 7,000 ppm. The resulting aromatic polycarbonate-dichloromethane solution was subjected to reflux dehydration, and dehydrated until the water content in the aromatic polycarbonate-dichloromethane solution reached 3000 ppm. The aromatic polycarbonate - in dichloromethane apparatus shown in FIG. 1, the cylinder of nitrogen (secondary pressure 3.3 kg / cm ²⁾ while maintaining the internal pressure of the autoclave to 3.0 kg / cm ^2, under stirring liquid temperature 80 ° C. Concentrated, polymer concentration 53.0
A wt% (calculated from the amount of dichloromethane flowing out) aromatic polycarbonate-dichloromethane solution was obtained. This solution was transferred to a Σ type kneader crusher (manufactured by Irie Shokai) with a jacket temperature of 40 ° C through a pipe that kept the temperature at 40 r under normal pressure.
The mixture was stirred and kneaded at pm. The polymer concentration in the solution immediately after the supply was 54.2% by weight, and the water content was 230 ppm. There was no foaming due to boiling of the aromatic polycarbonate-dichloromethane solution in the kneader grinder. Two
After 0 minutes, the content became a powder, and the apparent bulk density of the aromatic polycarbonate powdery material after being air-dried in a dryer at 150 ° C. for 3 hours was 0.68 g / 1 ml.

Comparative Example 1 Water content in a solution obtained by the same operation as in Example 230p
pm, aromatic polycarbonate-dichloromethane solution with a polymer concentration of 54.2% by weight, jacket temperature 50 ℃
Transfer to the Σ type kneader crusher, and under normal pressure, 40 rpm
The mixture was kneaded with stirring. The aromatic polycarbonate-dichloromethane solution in the kneader grinder was foamed by boiling. After 15 minutes, the contents became a powder and 1 in the dryer
The apparent bulk density of the aromatic polycarbonate powdery material after air drying at 50 ° C. for 3 hours was 0.60 g / 1 ml.

Comparative Example 2 The amount of water in the solution was 1600 pp according to Example 1 except that the aromatic polycarbonate-dichloromethane solution having a water content of 7000 ppm in the solution was directly concentrated without performing reflux dehydration.
An aromatic polycarbonate-dichloromethane solution with m and a polymer concentration of 50.0% by weight was obtained. When this solution was stirred and kneaded for 20 minutes in the same manner as in Example 1, the content was not solidified and was a sticky rice cake-like shape. The content became a powder 35 minutes after the start of stirring and kneading, and the apparent bulk density of the aromatic polycarbonate powder after being dried by ventilation in a dryer at 150 ° C. for 3 hours was 0.44 g / 1 ml.

Comparative Example 3 According to Example 1, except that reflux dehydration was performed until the water content in the aromatic polycarbonate-dichloromethane solution reached 2000 ppm, the autoclave internal pressure was 1.0 kg / cm ² , and the liquid temperature was 43 ° C. Water content 260ppm in solution,
An aromatic polycarbonate-dichloromethane solution having a polymer concentration of 36.0% by weight was obtained. This liquid was stirred and kneaded for 20 minutes in the same manner as in Example 1, but did not solidify. The content turns into powder in 60 minutes after the start of stirring and kneading, and is dried at 150 ° C
The apparent bulk density of the aromatic polycarbonate powder after ventilation drying for 3 hours was 0.68 g / 1 ml.

Example 2 An aromatic polycarbonate-dichloromethane solution having a water content of 230 ppm and a polymer concentration of 54.2% by weight was stirred and kneaded according to Example 1 except that the stirring number of the kneader pulverizer was 60 rpm. After 14 minutes, the content became a powder, and the apparent bulk density of the aromatic polycarbonate powder after air-dried at 150 ° C. for 3 hours in a dryer was 0.67 g.
It was / 1 ml.

Example 3 According to Example 1, the concentration of water in the solution was 140 ppm and the polymer concentration was 76.7, except that the internal pressure of the autoclave was maintained at 12.0 kg / cm ² and the solution was concentrated at 120 ° C. under stirring.
A wt% aromatic polycarbonate-dichloromethane solution was obtained. When the mixture was stirred and kneaded in the same manner as in Example 1, the content became a powder after 11 minutes, and the apparent bulk density of the aromatic polycarbonate powder after air-dried at 150 ° C. for 3 hours in a dryer was 0.67 g / It was 1 ml.

Example 4 Bisphenol A was reacted with phosgene in the presence of dichloromethane and sufficiently purified to give a number average molecular weight of 20,000.
An aromatic polycarbonate 15% by weight-dichloromethane solution having a weight average molecular weight of 52,000 was obtained. The amount of water in the obtained aromatic polycarbonate-dichloromethane solution was 9000 ppm. The resulting aromatic polycarbonate-dichloromethane solution was subjected to reflux dehydration, and dehydrated until the water content in the aromatic polycarbonate-dichloromethane solution reached 2000 ppm. 15% by weight of the above aromatic polycarbonate-100 kg of dichloromethane solution
Was concentrated in a jacketed pressure-resistant container 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 to give an aroma of a polymer concentration of 45.0% by weight (calculated from the amount of dichloromethane flowing out). A group polycarbonate-dichloromethane solution was obtained. This solution is used to pump 120
Kneader (Kurimoto Iron Works, SC Processor, Model SCP-1
(00) was continuously supplied to the hopper and kneaded while being concentrated at a jacket temperature of 40 ° C. and a stirring rate of 40 rpm. In addition,
Immediately after the supply, the polymer concentration in the solution was 46.2% by weight, and the water content was 90 ppm. By adjusting the supply amount, a maximum of 9.6 kg / h of aromatic polycarbonate powder was obtained. A part of the obtained aromatic polycarbonate powder was dried by ventilation in a dryer at 150 ° C. for 3 hours, and the apparent bulk density was measured and found to be 0.69 g / 1 ml.

Example 5 A maximum of 17.0 kg / h of aromatic polycarbonate powder was obtained in the same manner as in Example 4 except that the kneader was agitated at 80 rpm. A part of the obtained aromatic polycarbonate powder was dried by ventilation in a dryer at 150 ° C. for 3 hours, and the apparent bulk density was measured and found to be 0.68 g / 1 ml.

Comparative Example 4 According to Example 4, except that the jacket temperature of the kneader was 70 ° C., an aromatic polycarbonate powder having a maximum of 18.1 kg / h was obtained. A part of the obtained aromatic polycarbonate powder was dried by ventilation in a dryer at 150 ° C. for 3 hours, and the apparent bulk density was measured to be 0.53 to 0.5.
It was 6 g / 1 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 having a polymer concentration of 32.5% by weight and a water content of 570 ppm according to Example 6 except that
A dichloromethane solution was obtained. This solution was kneaded according to Example 4 while concentrating it at a jacket temperature of 40 ° C. and a stirring rate of 40 rpm. By controlling the supply amount, a maximum of 5.8 kg / h of aromatic polycarbonate powder was obtained. A part of the obtained aromatic polycarbonate powder is dried in a dryer at 150 ° C. 3
After air-drying for an hour, the apparent bulk density was measured and found to be 0.58 g / 1 ml. When the amount supplied was more than this, the aromatic polycarbonate did not solidify and became a sticky dough.

[0049]

According to the present invention, it is possible to obtain an aromatic polycarbonate powder having a high bulk density with an extremely short residence time, that is, a high processing capacity, without using a special device.

 ─────────────────────────────────────────────────── ─── 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 (2)

[Claims] 1. A method for producing an aromatic polycarbonate powdery material from an aromatic polycarbonate-dichloromethane solution obtained by an interfacial polymerization method, wherein a pressure of 45 is applied.
~ Polymer concentration obtained by concentrating at a temperature of 150 ° C ~ 40 ~
An aromatic polycarbonate-dichloromethane solution having a water content of 90 wt% and 500 ppm or less is fed into an apparatus having a kneading mechanism, and the precipitate is crushed while concentrating at a temperature equal to or lower than the boiling point of the aromatic polycarbonate-dichloromethane solution. A method for producing an aromatic polycarbonate powder, which comprises obtaining an aromatic polycarbonate powder. 2. The method for producing an aromatic polycarbonate powder according to claim 1, wherein the water content in the aromatic polycarbonate-dichloromethane solution is dehydrated by azeotropic distillation of water and an organic solvent.