JP5368031B2 - Continuous production method of polycarbonate granules - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing polycarbonate resin granular materials stably, continuously, with good productivity, and in a simple method allowing easy start-up, the polycarbonate resin granular materials having an extremely small amount of residual organic solvents and a uniform particle size. <P>SOLUTION: The method for continuously producing polycarbonate granular materials includes continuously feeding an organic solvent solution of a polycarbonate resin as it is or in a state of an emulsion of the organic solvent solution and warm water to a kneader having a pulverizing mechanism under atmospheric pressure or reduced pressure, with warm water present therein and held at T to T+40&deg;C, and includes removing the organic solvent, where T (&deg;C) is the boiling point of the organic solvent. In the method for producing polycarbonate granular materials, the resulting polycarbonate granular material slurry is withdrawn from the kneader and pulverized by a wet grinder and then the ratio of the granular material slurry circulated to the kneader to that fed to the next step is set at a weight ratio of 100:1 to 1:1. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a continuous production method for polycarbonate resin granules. More specifically, the present invention relates to a method for continuously and stably producing a polycarbonate resin granule having an extremely small amount of residual organic solvent and having a uniform particle diameter by a simple method that can be easily started up.

  Polycarbonate resins are usually produced by a so-called interfacial polycondensation method in which an alkaline aqueous solution of dihydric phenol and phosgene are reacted in the presence of an organic solvent such as methylene chloride, and an organic solvent solution of the resulting polycarbonate resin (hereinafter referred to as a polycarbonate resin solution). After the organic solvent is removed from the powder, it is subjected to a granulating step to form a granular material, and then subjected to a drying step.

  As a method for obtaining a granule by removing an organic solvent from a polycarbonate resin solution, for example, a method of contacting a polycarbonate resin solution with hot water to form a gelled product and then pulverizing (Patent Documents 1, 2, etc.) is known. Yes.

  However, a large amount of organic solvent still remains in the granular material obtained by these methods, and it is difficult to sufficiently remove the residual organic solvent by ordinary drying. In order to further reduce the residual organic solvent, it is necessary to dry at a high temperature for a long time. The drying process becomes large or complicated, and still tens to hundreds of ppm of organic solvent remains.

  In addition, as a method for producing a polycarbonate resin granule having a small amount of residual organic solvent, a method of adding a non-solvent or a poor solvent to a polycarbonate resin solution obtained by reaction or a polycarbonate resin slurry in which the organic solvent remains, or an organic solvent remains The method (patent documents 3-6 etc.) of extracting the polycarbonate resin granular material to perform with a poor solvent is proposed.

  In these methods, although the organic solvent is sufficiently removed, a large amount of non-solvent or poor solvent remains, and this residual non-solvent or poor solvent is dried at a high temperature for a long time as well as normal drying. However, it is difficult to remove them sufficiently. Moreover, in order to use the recovered organic solvent again, a large amount of energy is required to purify and remove the used non-solvent and poor solvent.

  Also known is a method (Patent Documents 7, 8, etc.) in which a polycarbonate resin solution is supplied into a slurry liquid circulated with a wet pulverizer and heated while maintaining a suspended state.

  However, in these methods, in order to generate a suspended state, a strong stirring power is required, and the resin solution adheres and grows on the granulation tank wall, stirring blade, etc., and generates a solid solid matter. cause. Further, if the powdered body is not previously dispersed in warm water at the time of start-up, the resin solution adheres to the granulation tank wall, the stirring blade, etc., and the operation itself is difficult.

  On the other hand, as a method for granulating polycarbonate resin without using water, the polycarbonate resin granules are retained in the granulation tank in advance, and the granules are stirred in an atmosphere in which the organic solvent evaporates, and the organic solvent solution is added to the organic solvent solution. A method (e.g., Patent Documents 9 and 10) in which an organic solvent is evaporated while being in contact with a granular material has been proposed. However, it is necessary to prepare a granular material in advance, and since there is no water, there is a problem that heat transfer efficiency is poor and equipment is enlarged. Moreover, many organic solvents still remain in the granular material obtained by these methods, and it is difficult to sufficiently remove the residual organic solvent by ordinary drying.

  As a method of obtaining a granular material by removing an organic solvent from a polycarbonate resin solution, a method of removing the solvent indirectly by introducing it into a non-solvent such as water is more effective than removing the solvent directly from the resin solution. From the aspect, it is preferable. However, when the resin solution is poured into the water under stirring, the granular material that contains a large amount of organic solvent generated by crushing the lump that has adhered and grown to the granulation tank wall, stirring blade, etc. There is a problem that the concentration of the residual organic solvent in the product is increased by mixing in the product.

Japanese Patent Publication No. 45-009875 Japanese Patent Publication No. 04-001767 Japanese Patent Publication No.55-001298 JP-A 63-278929 JP-A-01-006020 Japanese Patent Publication No. 05-012371 Japanese Examined Patent Publication No. 63-054011 Japanese Patent Publication No. 03-04493 Japanese Patent No. 3196274 Japanese Patent No. 28888769

  An object of the present invention is to provide a method for continuously producing a polycarbonate resin granule having a very small amount of residual organic solvent stably and with good productivity by a simple method that can be easily started up. .

  As a result of earnest research that the present inventors have achieved the above object, the polycarbonate resin solvent solution is used as it is or in a kneader having a grinding mechanism at atmospheric pressure or under reduced pressure in the state of an emulsion of an organic solvent solution and warm water. In the process of continuously supplying, removing the organic solvent, and producing the polycarbonate granules, the produced polycarbonate granules slurry is extracted from the kneader and pulverized by a wet pulverizer, and part of the slurry is kneaded. The inventors have found that the above object can be achieved by a method that circulates in the above manner, and have reached the present invention.

That is, according to the present invention,
1. The polycarbonate resin organic solvent solution is continuously supplied to a kneader having a pulverizing mechanism under atmospheric pressure or reduced pressure, where the boiling point of the organic solvent is T (° C.) and hot water maintained at T to T + 40 ° C. is present. A method for producing a polycarbonate granule by removing an organic solvent, wherein the produced polycarbonate granule slurry is extracted from the kneader, pulverized by a wet pulverizer, and then circulated to the kneader out of the granule slurry. The ratio of the one to be supplied to the next step is 100: 1 to 1: 1 by weight, and the internal pressure of the kneader is in the range of -0.02 to 0 MPa in difference from atmospheric pressure. it, and the weight ratio (polycarbonate / water) with kneader polycarbonate resin granules and hot water of the polycarbonate granules which is a range of 0.1 to 1.0 How to continue production,
2. A polycarbonate resin organic solvent solution and warm water were continuously introduced into a dispersion tank and sheared to form an emulsion, and the emulsion was maintained at T to T + 40 ° C. with the boiling point of the organic solvent being T (° C.). A method for producing polycarbonate granules by continuously supplying to a kneader having a pulverization mechanism under atmospheric pressure or reduced pressure in the presence of warm water, and removing the organic solvent. After being extracted from the machine and pulverized by a wet pulverizer, the ratio of the granular slurry to the one circulating in the kneader and the one supplied to the next step is 100: 1 to 1: 1. it, the internal pressure of the kneader that the difference between the atmospheric pressure is in the range of -0.02～0MPa, and heavy with kneader polycarbonate resin granules and hot water Ratio (polycarbonate / water) continuous production method of the polycarbonate granules, characterized in that in the range of 0.1 to 1.0, and 3. The continuous production method of a polycarbonate granule according to the preceding item 1 or 2, wherein a kneader having grooves or protrusion-like teeth on a blade and / or barrel is used as the kneading machine,
Is provided.

  The polycarbonate resin used in the present invention is a resin usually used as an engineering resin, and is an aromatic polycarbonate resin obtained by reacting a dihydric phenol and a carbonate precursor. As the dihydric phenol used here, 2,2-bis (4-hydroxyphenyl) propane (commonly called bisphenol A) is preferably used. Examples of other dihydric phenols include bis (hydroxyaryl) alkanes such as bis (4-hydroxyphenyl) methane and bis (hydroxyaryl) cyclo such as 1,1-bis (4-hydroxyphenyl) cyclopentane. Examples include alkanes and 4,4-dihydroxydiphenyl, and halogenated bisphenols such as 2,2-bis (3,5-dibromo-4-hydroxyphenyl) propane.

  Examples of the carbonate precursor include carbonyl halide, diaryl carbonate, haloformate, and the like, and specifically, phosgene, diphenyl carbonate, dihaloformate of dihydric phenol, and the like.

  In producing the aromatic polycarbonate resin by reacting the dihydric phenol and the carbonate precursor, a catalyst, a molecular weight adjusting agent, an antioxidant or the like may be used as necessary. It may be a branched polycarbonate resin copolymerized with a trifunctional or higher polyfunctional aromatic compound, or a mixture of two or more aromatic polycarbonate resins.

Any molecular weight of the aromatic polycarbonate resin can be used, and it is not necessary to limit the molecular weight. For example, when the aromatic polycarbonate resin is obtained using bisphenol A as the dihydric phenol and phosgene as the carbonate precursor, The molecular weight is preferably 1.2 × 10 ^{4 to} 5.0 × 10 ⁴ in terms of viscosity average molecular weight.

The viscosity average molecular weight referred to in the present invention is first determined by using an Ostwald viscometer from a solution in which 0.7 g of polycarbonate resin is dissolved in 100 ml of methylene chloride at 20 ° C., with a specific viscosity (η _SP ) calculated by the following formula:
Specific viscosity (η _SP ) = (t−t ₀ ) / t ₀
[T ₀ is methylene chloride falling seconds, t is sample solution falling seconds]
The viscosity average molecular weight M is calculated from the determined specific viscosity (η _SP ) by the following formula.
η _SP /c=[η]+0.45×[η] ² c (where [η] is the intrinsic viscosity)
[Η] = 1.23 × 10 ⁻⁴ M ^0.83
c = 0.7

In addition, when measuring the viscosity average molecular weight of the polycarbonate resin of this invention, it can carry out in the following way. That is, the polycarbonate resin is dissolved in 20 to 30 times the weight of methylene chloride, and the soluble component is collected by celite filtration, and then the solution is removed and dried sufficiently to obtain a solid component soluble in methylene chloride. A specific viscosity (η _SP ) at 20 ° C. is determined from a solution obtained by dissolving 0.7 g of the solid in 100 ml of methylene chloride using an Ostwald viscometer, and the viscosity average molecular weight M is calculated by the above formula.

  The continuous production method of the aromatic polycarbonate resin granule of the present invention is extremely suitable for using an aromatic polycarbonate resin solution obtained by an interfacial condensation polymerization method using an organic solvent. That is, this invention is suitable for obtaining the granular material from the aromatic polycarbonate resin solution obtained by reacting dihydric phenol and phosgene in an organic solvent. The organic solvent used at this time is a good solvent for the aromatic polycarbonate resin and is a solvent immiscible with water.

  The organic solvent referred to in the present invention includes at least one good solvent as a main solvent, preferably 1,1,2,2-tetrachloroethane, methylene chloride, 1,2-ethylene dichloride, chloroform, 1,1. 2,2-trichloride ethane, 1,2-ethane dichloride, dioxane, tetrahydrofurane, dioxolane and the like can be used. Particularly preferably, methylene chloride (atmospheric pressure boiling point 40 ° C.) is used. As such an organic solvent, a solvent in which 90% by volume or more of the solvent is a good solvent is preferably used, and a solvent substantially consisting of a good solvent is particularly preferably used.

  In the present invention, the organic solvent used may contain a poor solvent that does not precipitate the polymer. Examples of such poor solvents include aliphatic hydrocarbons such as heptane, hexane and pentane, and aromatic hydrocarbons such as benzene, toluene and xylene.

  The polycarbonate resin solution obtained by the above-mentioned interfacial polycondensation method is usually filtered for removing insoluble impurities, and washed with water for removing water-soluble impurities and catalysts, and with acid washing or alkali washing as necessary. Etc. are performed.

  The polycarbonate resin solution having been subjected to the above treatment is then subjected to an operation of removing the solvent to obtain a polycarbonate resin granule. Under the present circumstances, the density | concentration of this polycarbonate resin solution is 5-30 weight% normally. If the concentration is within this range, the solution viscosity is appropriate, it is easy to handle in industrial production equipment, the solution is easy to wash, the filtration efficiency is good, and there are not too many organic solvents. When removing water, it does not require excessive energy and is advantageous in terms of economical production.

  Although the density | concentration of the polycarbonate organic solvent solution used by this invention is not restrict | limited in particular, Preferably it is 5 to 30 weight%, More preferably, it is 5 to 25 weight%. The purified resin solution can be used as it is or after concentration. In the present invention, the polycarbonate organic solvent solution is continuously supplied to a kneader having a pulverizing mechanism under atmospheric pressure or reduced pressure as it is or in an emulsion of the organic solvent solution and warm water.

  The internal pressure of the kneader may be any pressure as long as it is under atmospheric pressure or reduced pressure. However, the organic solvent can be easily removed by reducing the pressure, but the power of the blower or vacuum pump for reducing the pressure is excessive and disadvantageous in terms of energy. The conditions of slightly reduced pressure are applied. Specifically, the internal pressure of the kneader is preferably in the range of −0.02 to 0 MPa in difference from atmospheric pressure.

The volume ratio of the resin solution to form the emulsion and warm water varies depending on the type of polycarbonate resin, molecular weight, concentration in the resin solution, etc., but is usually 1: 0.2 to 3, preferably 1: 0.2-2. When there is too much quantity of warm water with respect to a resin solution, the fall of the slurry density | concentration at the time of granulation will be caused, and a grinding mechanism will not work effectively.
Any dispersion tank for forming an emulsion can be used as long as it can form an emulsion, and a normal stirring tank is sufficient.

An example of a kneader having a pulverizing mechanism used in the present invention is shown in the drawings.
FIG. 1 is a simplified cross-sectional view of a double-arm kneader, and FIG. 2 is a simplified side view of the sigma-type wing. This kneader is composed of a sigma type wing 1 installed in parallel and a barrel 2 with a jacket for housing it, and kneading is performed by rotating the wing. Further, as shown in FIG. 1, the kneader is provided with a protrusion 3 in the longitudinal direction of the barrel and a sawtooth protrusion 4 on the periphery of the sigma type blade 1. The sawtooth protrusion 4 has a shape as shown in FIG. 3, and the shape of the protrusion 3 formed on the inner surface of the barrel 2 has a cross section as shown in FIG. As the irregularities formed on the inner surface of the barrel 2, a number of protrusions may be provided as shown in FIG. 5 instead of the protrusions 3 shown in FIGS. 1 and 4. As such ridges and protrusions for grinding, the height is preferably about 3 to 20 mm, the pitch (teeth-to-teeth spacing) is about 3 to 20 mm, and the curvature radius of the tip is preferably about 1 to 5 mm. The clearance between the blade and the barrel is preferably 1 to 50 mm.

  If the temperature of the kneader is too low, the evaporation of the organic solvent will slow down and the granulation processing ability will decrease, or the dryness of the resin granules after granulation will deteriorate, and conversely the resin obtained if it is too high Since the bulk density of the granular material tends to be too small, it is necessary to keep the temperature of the hot water in the kneader in the temperature range of T to T + 40 ° C., where the boiling point of the organic solvent is T (° C.). The temperature range is preferably T + 2 ° C. to T + 32 ° C. For example, when methylene chloride is used as the organic solvent, the temperature is in the range of 40 to 80 ° C, and preferably in the temperature range of 42 to 72 ° C.

  It is not necessary to prepare a granular material in the kneader in the initial stage of startup, and it is sufficient to continuously supply a polycarbonate resin solution or an emulsion of an organic solvent solution and warm water to warm water, such as a kneader wall and a stirring blade. It is possible to move to stable continuous granulation without adhesion of resin mass to the surface.

  The weight ratio (polycarbonate / water) between the polycarbonate resin granules and the hot water in the kneader is preferably in the range of 0.1 to 1.0, particularly 0.15 to 0 in terms of stirring and slurry handling and grinding efficiency. A range of .8 is preferred. When the slurry concentration is too high, there is a problem in handling, and when it is too low, the pulverization efficiency of the kneader decreases. The ratio of the polycarbonate resin granular material and the hot water is adjusted by adjusting the ratio of the polycarbonate resin solution introduced into the kneader and the makeup water, the ratio of the polycarbonate resin solution supplied to the dispersion tank when forming the emulsion and the hot water, It is preferable to keep within the range.

  In the present invention, the water slurry of the polycarbonate granules grown from the kneader is extracted and pulverized by a wet pulverizer. As the wet pulverizer, any solid pulverizer can be used as long as it can pulverize the solid in the liquid. However, a wet pulverizer having a transport function is suitable. For example, a commercially available product is a disc manufactured by Huxburner Zenoa Co., Ltd. Integrator, Primix Co., Ltd. K. Examples include homomic line mills and trigonals manufactured by Mitsui Mining Co., Ltd. Further, it is possible to use a pump and a pulverizer in combination. In the case of using a pump, in addition to the above pulverizer, a hammer mill or feather mill manufactured by Hosokawa Micron Co., Ltd., a hammer mill or cutter mill manufactured by Nara Machinery Co., Ltd. may be used.

  The pulverization by the wet pulverizer is preferably performed until the average particle diameter of the polycarbonate granules in the pulverized slurry is about 0.4 to 4 mm, and preferably pulverized until the average particle diameter is about 0.5 to 3 mm. good. If the average particle size after pulverization is too large, the dryness of the resin granules deteriorates, so there is a problem of increasing the residual organic solvent concentration of the product. Conversely, if the average particle size is too small, wet pulverization The load on the machine becomes excessive, and not only a large amount of energy is required, but also the wet crusher may be blocked. In addition, the handleability of the product also deteriorates.

  Of the granular slurry subjected to the wet pulverization treatment, the ratio of the one circulating to the kneader and the one supplied to the next step is in the range of 100: 1 to 1: 1 by weight, preferably 50: 1 to 1. The range is 2: 1. If the ratio of circulation to the kneading machine is too small, the particles formed by the kneading machine become large, the load on the kneading machine and the wet pulverizer becomes large, and the problem that the drying property of the resin granule deteriorates also occurs. On the other hand, when the ratio of circulation to the kneader is too large, the liquid pump or the motor of the wet pulverizer becomes excessive, which is disadvantageous in terms of energy.

In order to obtain a polycarbonate granule from the polycarbonate granule slurry supplied to the next step, after evaporating the solvent in hot water at a temperature higher than the temperature at the time of granulation, the slurry is subjected to means such as inclination, filtration, and centrifugation. The granular material may be separated and dried.
Arbitrary stabilizers, additives, fillers and the like can be added to the polycarbonate resin granules thus obtained as required.

  According to the present invention, an extremely excellent polycarbonate resin granule having a small amount of residual solvent and having a uniform particle size and being easy to handle by ordinary drying can be stably produced by a simple method that can be easily started up. It can be manufactured continuously with good performance, and the industrial effect it produces is exceptional.

Examples of the present invention will be described below for further description. In the examples,% is% by weight, and the pressure is gauge pressure.
(1) Methylene chloride content: The chlorine content was measured with a total organic halogen analyzer [TOX manufactured by Mitsubishi Kasei Co., Ltd.] and converted to the amount of methylene chloride.
(2) Viscosity average molecular weight: Specific viscosity (η _sp ) was measured with an Ostwald viscometer at 20 ° C. using a solution obtained by dissolving 0.7 g of polycarbonate resin in 100 ml of methylene chloride, and calculated according to the following formula.
η _sp / C = [η] + K [η] ² C
[Η] = 1.23 × 10 ⁻⁴ M ^0.83
(In the formula, C is a concentration of 0.7, and K is a constant of 0.45)
(3) Average particle size: In accordance with the particle size measurement method of “Granulation Handbook” edited by Japan Powder Industry Association, Chapter 1, Chapter 2, 2 and 4, the samples were 13.2 mm, 8.0 mm, 4.75 mm. 2.8 mm, 1.7 mm, 1.0 mm, 0.71 mm, 0.5 mm, 0.3 mm, 0.18 mm A particle size distribution graph was created, and the particle size at which the cumulative weight reached 50% was determined and used as the average particle size.
(4) Bulk density: Put a polycarbonate resin sample into a metal cylinder of 100 cm ³ using a funnel, scrape off the excess, weigh it, determine the weight W (g) of the contents, and calculate by the following formula did.
Bulk density (g / cm ³ ) = W / 100

[Example 1]
It has a solution supply port, steam inlet, hot water inlet, steam outlet, and slurry outlet as a kneading machine, using a sigma-type double-armed 50 liter kneader with a blade diameter of 17 cm, and Huxburner Zenoah Co., Ltd. as a wet mill ) Disintegrator made.
A methylene chloride solution (concentration 16) of viscosity-average molecular weight 25,000 which was synthesized from bisphenol A and phosgene by a conventional method and purified in a kneader containing 40 kg of warm water of 45 ° C. and stirred at 150 rpm under atmospheric pressure. % By weight) was continuously supplied from the solution supply port at a rate of 47.7 liter / hr, and at the same time, steam at a pressure of 0.3 MPa and warm water at 45 ° C. were respectively 11.0 kg / hr and 9.5 liter / hr. Introduced at a speed of. In addition, the weight ratio (polycarbonate / warm water) of the polycarbonate granular material in the kneader after 6 hours and warm water was 0.51.

The water temperature is maintained at 45 ° C., the slurry is extracted from the slurry outlet of the kneader, wet pulverized using a wet pulverizer, and the slurry after wet pulverization is circulated to the kneader at 400 liters / hr, while 29. The water slurry of 8 liters / hr was continuously discharged, and at the same time, the evaporated methylene chloride was separated from the entrained water through the vapor discharge port to recover the methylene chloride. The amount of residual methylene chloride in the polycarbonate granules of the discharged water slurry was 23% by weight.
The discharged water slurry was separated into polycarbonate granules by a centrifugal dehydrator, and dried with hot air at 140 ° C. for 6 hours. The methylene chloride content of the granules after drying was 10.6 ppm, the average particle size was 1.3 mm, and the bulk density was 0.59 g / cm ³ .

[Example 2]
The same apparatus as in Example 1 was used, except that the temperature of the hot water stored in the kneader, the temperature of the supplied hot water, and the temperature of the kneader maintained during granulation were all set to 70 ° C. Polycarbonate granules were obtained.
The amount of water slurry discharged continuously was 29.0 liter / hr, the amount of residual methylene chloride in the polycarbonate granules of the discharged water slurry was 3.0% by weight, and the methylene chloride of the granules after drying The content was 4.0 ppm, the average particle size was 1.8 mm, and the bulk density was 0.35 g / cm ³ .

[Example 3]
Using the same apparatus as in Example 1, except that the amount of slurry extracted from the slurry outlet of the kneader is 130 liters / hr, and among the wet pulverized slurry, the amount of slurry circulated to the kneader is 100 liters / hr, In the same manner as in Example 1, polycarbonate granules were obtained.
The amount of water slurry discharged continuously is 30.0 liter / hr, the amount of residual methylene chloride in the polycarbonate granules of the discharged water slurry is 26% by weight, and the methylene chloride content of the granules after drying Was 45.0 ppm, the average particle size was 2.6 mm, and the bulk density was 0.64 g / cm ³ .

[Example 4]
In Example 1, a methylene chloride solution (concentration 8.5% by weight) of a polycarbonate having a viscosity average molecular weight of 30,000 synthesized and purified from bisphenol A and phosgene by a conventional method was continuously added at a rate of 90.0 l / hr. The conditions other than starting the introduction of water vapor at a pressure of 0.3 MPa and hot water at 45 ° C. at a rate of 15.8 kg / hr and 18.0 liters / hr, respectively, are implemented. In the same manner as in Example 1, polycarbonate granules were obtained.
The amount of water slurry discharged continuously is 45.5 liters / hr, the amount of residual methylene chloride in the polycarbonate granules of the discharged water slurry is 18% by weight, and the methylene chloride content of the granules after drying Was 30.5 ppm, the average particle size was 1.5 mm, and the bulk density was 0.56 g / cm ³ .

[Example 5]
In Example 1, a methylene chloride solution (concentration: 24.0% by weight) of a polycarbonate having a viscosity average molecular weight of 15,000 synthesized and purified from bisphenol A and phosgene by a conventional method was continuously added at a rate of 31.8 l / hr. In addition, the conditions other than the introduction of water vapor at a pressure of 0.3 MPa and hot water at 45 ° C. at a rate of 7.6 kg / hr and 9.5 liter / hr, respectively, are implemented. In the same manner as in Example 1, polycarbonate granules were obtained.
The amount of water slurry discharged continuously is 27.0 l / hr, the amount of residual methylene chloride in the polycarbonate granules of the discharged water slurry is 25% by weight, and the methylene chloride content of the granules after drying Was 6.6 ppm, the average particle size was 1.3 mm, and the bulk density was 0.62 g / cm ³ .

[Example 6]
It has a solution supply port, water vapor inlet port, hot water inlet port, steam outlet port and slurry outlet port as a kneading machine, using a sigma type double-armed 250 liter kneader with a blade diameter of 30 cm, and Huxburner Xenoah Co., Ltd. ) Disintegrator made.
A methylene chloride solution (concentration of 16) having a viscosity average molecular weight of 25,000, synthesized in a conventional manner from bisphenol A and phosgene in the above kneader containing 200 kg of warm water of 45 ° C. and stirred at 120 rpm under atmospheric pressure. % By weight) is continuously supplied from the solution supply port at a rate of 47.7 liter / hr, and at the same time, steam at a pressure of 0.3 MPa and hot water at 45 ° C. are supplied at a rate of 46 kg / hr and 48 liter / hr, respectively. Introduced. In addition, the weight ratio (polycarbonate / warm water) of the polycarbonate granular material in the kneader after 6 hours and warm water was 0.56.

While maintaining the water temperature at 45 ° C., withdrawing from the slurry outlet of the kneader, wet pulverizing using a wet pulverizer, 140 liters while circulating 5.2 m ³ / hr of the wet pulverized slurry to the kneader The water slurry of / hr was continuously discharged, and at the same time, the evaporated methylene chloride was separated from the entrained water through the vapor outlet to the condenser, and methylene chloride was recovered. The amount of residual methylene chloride in the polycarbonate granules of the discharged water slurry was 22% by weight.
The discharged water slurry was separated into polycarbonate granules by a centrifugal dehydrator, and dried with hot air at 140 ° C. for 6 hours. The dried granular material had a methylene chloride content of 12.5 ppm, an average particle size of 1.4 mm, and a bulk density of 0.60 g / cm ³ .

[Example 7]
Wet grinding using a 50 liter jacketed stirrer equipped with 6 turbine blades (blade diameter 16 cm) and two stirrer blades as a dispersion tank, and a sigma blade double arm 50 liter kneader with a blade diameter of 17 cm as a kneader A disintegrator manufactured by Huxburna Zenoah Co., Ltd. was used as the machine.
Chlorination of polycarbonate having a viscosity average molecular weight of 25,000 synthesized and purified from bisphenol A and phosgene by a conventional method in the above-mentioned dispersion tank stirred at 400 rpm under a pressure of 0.05 MPa and containing 40 kg of warm water of 45 ° C. A methylene solution (concentration: 16% by weight) was continuously supplied at a rate of 47.7 liter / hr, and at the same time, introduction of 45 ° C. hot water at a rate of 47.7 / hr was started to prepare an emulsion. Note that warm water was passed through the dispersion tank jacket, and the internal temperature of the dispersion tank was maintained at 45 ° C. Next, while controlling with a control valve so that the liquid level in the dispersion tank is constant, the prepared emulsion is derived from the emulsion outlet, and the derived emulsion is filled with 40 kg of warm water of 45 ° C. at 150 rpm under atmospheric pressure. The kneader was continuously fed to the stirring kneader, and at the same time, introduction of steam at a pressure of 0.3 MPa into the kneader at a rate of 10.6 kg / hr was started. In addition, the weight ratio (polycarbonate / warm water) of the polycarbonate granular material in the kneader after 6 hours and warm water was 0.18.

67. While maintaining the water temperature at 45 ° C., withdrawing the slurry from the slurry outlet of the kneader, performing wet pulverization using a wet pulverizer, and circulating 2000 l / hr of the wet pulverized slurry to the kneader, The water slurry of 0 liter / hr was continuously discharged, and at the same time, the evaporated methylene chloride was separated from the entrained water through the vapor discharge port to collect the methylene chloride. The amount of residual methylene chloride in the polycarbonate granules of the discharged water slurry was 15% by weight.
The discharged water slurry was separated into polycarbonate granules by a centrifugal dehydrator, and dried with hot air at 140 ° C. for 6 hours. The dried granular material had a methylene chloride content of 7.2 ppm, an average particle size of 1.3 mm, and a bulk density of 0.55 g / cm ³ .

[Example 8]
Using the same apparatus as in Example 7, polycarbonate granules were obtained in the same manner as in Example 7 except that the polycarbonate methylene chloride solution supplied to the dispersion tank was changed to 85.9 liter / hr. The amount of water slurry discharged continuously is 105.0 liters / hr, the amount of residual methylene chloride in the polycarbonate granules of the discharged water slurry is 13% by weight, and the methylene chloride content of the granules after drying Was 5.3 ppm, the average particle size was 1.4 mm, and the bulk density was 0.50 g / cm ³ .

[Comparative Example 1]
In place of the kneader used in Example 1, a 50 liter stirring tank equipped with three fowler blades (blade diameter 16 cm) and two stages of stirring blades was used, and 40 kg of 45 ° C. hot water was added and stirred at 250 rpm. The organic solvent solution and hot water were supplied in the same manner as in Example 1, but the adhesion to the stirring vessel wall and the stirring blade was severe, and operation was impossible.

[Comparative Example 2]
Instead of the kneader used in Example 7, a 50 liter stirring tank equipped with three fowler blades (blade diameter 16 cm) and two stages of stirring blades was used, and 40 kg of 45 ° C. warm water was added and stirred at 250 rpm. In the same manner as in Example 7, an organic solvent solution and warm water were supplied to the dispersion tank to prepare an emulsion, and the emulsion was supplied from the emulsion discharge outlet to the stirring tank while being controlled by a control valve so as to be constant. Although not as much as Comparative Example 1, the adhesion to the stirring vessel wall and the stirring blade was severe, and operation was impossible.

[Comparative Example 3]
Instead of the wet pulverizer used in Example 1, a slurry pump manufactured by Sanwa Hydrotech Co., Ltd. was used, and other conditions were the same as in Example 1, and polycarbonate granules were obtained. The amount of water slurry discharged continuously was 29.9 liters / hr, the amount of methylene chloride remaining in the polycarbonate granules of the discharged water slurry was 35% by weight, and the methylene chloride content of the granules after drying Was 2100 ppm, the average particle size was 5.5 mm, and the bulk density was 0.62 g / cm ³ .

[Comparative Example 4]
Using the apparatus used in Example 1, polycarbonate granules were obtained in the same manner as in Example 1 except that the amount of slurry circulated to the kneading machine was 25 liters / hr among the wet pulverized slurry. The amount of water slurry discharged continuously is 29.7 l / hr, the amount of methylene chloride remaining in the polycarbonate granules of the discharged water slurry is 26% by weight, and the methylene chloride content of the granules after drying Was 330 ppm, the average particle size was 4.2 mm, and the bulk density was 0.63 g / cm ³ .

It is the figure which showed simplified sectional drawing of an example of the kneading machine used for this invention. It is the figure which showed the simplified side view of the stirring blade of FIG. It is the figure which showed the partial side view of the serrated protrusion formed in the stirring blade. It is the figure which showed the partial side view of the protrusion formed in the barrel. It is the figure which showed the partial side view of the protrusion formed in the barrel.

Explanation of symbols

1. Stirring blade 1. Barrel 3. A protrusion formed on the barrel. Serrated protrusions P _{1 to} P ₃ formed on the periphery of the stirring blade. Intervals between protrusions and protrusion teeth and teeth R _{1 to} R ₃ . Curvature radius of protrusion tip and protrusion tip h _{1 to} h ₃ . Height of protrusions and ridges

Claims (3)

The polycarbonate resin organic solvent solution is continuously supplied to a kneader having a pulverizing mechanism under atmospheric pressure or reduced pressure, where the boiling point of the organic solvent is T (° C.) and hot water maintained at T to T + 40 ° C. is present. A method for producing a polycarbonate granule by removing an organic solvent, wherein the produced polycarbonate granule slurry is extracted from the kneader, pulverized by a wet pulverizer, and then circulated to the kneader out of the granule slurry. The ratio of the one to be supplied to the next step is 100: 1 to 1: 1 by weight, and the internal pressure of the kneader is in the range of -0.02 to 0 MPa in difference from atmospheric pressure. it, and the weight ratio (polycarbonate / water) with kneader polycarbonate resin granules and hot water of the polycarbonate granules which is a range of 0.1 to 1.0 Continued manufacturing method. A polycarbonate resin organic solvent solution and warm water were continuously introduced into a dispersion tank and sheared to form an emulsion, and the emulsion was maintained at T to T + 40 ° C. with the boiling point of the organic solvent being T (° C.). A method for producing polycarbonate granules by continuously supplying to a kneader having a pulverization mechanism under atmospheric pressure or reduced pressure in the presence of warm water, and removing the organic solvent. After being extracted from the machine and pulverized by a wet pulverizer, the ratio of the granular slurry to the one circulating in the kneader and the one supplied to the next step is 100: 1 to 1: 1. it, the internal pressure of the kneader that the difference between the atmospheric pressure is in the range of -0.02～0MPa, and heavy with kneader polycarbonate resin granules and hot water Ratio (polycarbonate / water) continuous process polycarbonate granules, characterized in that in the range of 0.1 to 1.0.   The continuous manufacturing method of the polycarbonate granular material of Claim 1 or 2 using the kneader which provided the groove | channel or the protrusion-shaped tooth | gear in the wing | blade and / or the barrel as the said kneading machine.

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