JP2011026471A - Continuous production method for polycarbonate granules - Google Patents

Abstract

[Problem] To provide a method for continuously producing a polycarbonate granule having an extremely small amount of residual organic solvent and having a uniform particle diameter in an efficient manner with high productivity.
A polycarbonate resin organic solvent solution and warm water are mixed with a static mixer under pressure to form an oil-in-water dispersion (O / W) emulsion, and the boiling point of the organic solvent at atmospheric pressure is T ( ℃) as a method of continuously supplying to a granulation tank maintained at T ℃ ~ T + 50 ℃, removing the organic solvent to produce polycarbonate granules, the Weber number (We) in the static mixer is 2 * 10 < ¹ > -2 * 10 < ⁴ >, The continuous manufacturing method of the polycarbonate granular material characterized by the above-mentioned.
[Selection figure] None

Description

  The present invention relates to a continuous production method for polycarbonate granules. More specifically, the present invention relates to a method for continuously producing a polycarbonate granule having an extremely small amount of residual organic solvent and having a uniform particle diameter in an efficient manner with good productivity.

  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.

  In order to improve these, a mixed solution of a polycarbonate resin solution and water is mixed at a high linear velocity or shear force to form a suspended state, and the resulting suspension is heated to remove the organic solvent, A method of granulating (Patent Documents 9, 10, etc.) has been proposed. However, there is a problem that a large amount of energy is required to obtain a high linear velocity or shear force. Moreover, the granular material obtained by these methods had a small bulk density and poor handleability.

  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. Alternatively, when a suspension in which a mixed solution of a polycarbonate resin solution and water is mixed at a high linear velocity or shear force, a large amount of energy is required to produce the suspension, and the product is bulky. There was a problem that the density decreased.

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. 3551211 Special table 2003-518536 gazette

  An object of the present invention is to provide a method for continuously producing a polycarbonate granule having very little residual organic solvent in an efficient manner, stably and with high productivity.

As a result of diligent research to achieve the above object, the present inventors have mixed an organic solvent solution of polycarbonate resin with hot water under high pressure, and an oil-in-water dispersion type (O / W) solution by a static mixer. This is a liquid dispersion (emulsion), which is continuously supplied to the granulation tank, and the organic solvent is removed to produce polycarbonate granules. The Weber number (We) in the static mixer is 2 × 10 ¹ to 2 By making it × 10 ⁴ , the inventors have found that the above object can be achieved, and have reached the present invention.

That is, according to the present invention,
1. The polycarbonate resin organic solvent solution and warm water are mixed with a static mixer under pressure to form an oil-in-water dispersion (O / W) emulsion, and the boiling point of the organic solvent at atmospheric pressure is T (° C.). A method of continuously supplying to a granulation tank maintained at T ° C. to T + 50 ° C. and removing an organic solvent to produce a polycarbonate granule having a Weber number (We) of 2 × 10 ^{1 in} a static mixer. A continuous production method of polycarbonate granules, characterized in that it is ˜2 × 10 ⁴ ,
2. The method for continuously producing a polycarbonate granule according to item 1 above, wherein the temperature of the oil-in-water dispersion (O / W) emulsion is in the range of T ° C to T + 80 ° C.
3. 3. The method for continuously producing polycarbonate granules according to item 1 or 2, wherein at least part of the produced polycarbonate granules is extracted, pulverized by a wet pulverizer, and then circulated into a granulation tank to produce polycarbonate granules. ,
4). 4. The continuous production method of a polycarbonate granule according to any one of items 1 to 3, wherein a kneader provided with grooves or protrusions on a blade and / or barrel is used as the granulation tank; After adjusting the water slurry of the polycarbonate granules obtained in the preceding items 1 to 4 to T + 20 ° C. to T + 60 ° C., dehydration is performed to separate and recover the polycarbonate granules, and the hot water separated from the granules is used for emulsion formation. The continuous manufacturing method of the polycarbonate granular material of any one of Claims 1-4 used as warm water,
Is provided.

  According to the present invention, it is possible to continuously produce an excellent polycarbonate granule having an extremely small residual solvent by normal drying and having a uniform particle size and easy to handle, in an efficient manner, with high productivity. The industrial effect is exceptional.

It is the figure which showed the simplified sectional drawing of an example of the kneading machine (kneader) used suitably by 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.

  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 its weight of methylene chloride, and the soluble component is collected by celite filtration. Then, the solution is removed and dried sufficiently to obtain a solid component of methylene chloride soluble component. 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 mixed with warm water by a static mixer under pressure, and the pressure at that time is a pressure at which the organic solvent does not evaporate. The temperature of the emulsion after mixing is preferably T ° C. to T + 80 ° C., where the boiling point of the organic solvent at atmospheric pressure is T (° C.). Therefore, the temperature of the hot water used is preferably T ° C to T + 80 ° C. For example, when methylene chloride is used as the organic solvent, a preferable temperature of hot water is in the range of 40 to 120 ° C, and a preferable temperature of the emulsion obtained after mixing is in the range of 40 to 120 ° C. The pressure is preferably in the range of 0.1 to 1.0 MPa. There are a method of heating the polycarbonate organic solvent solution before mixing, a method of heating water before mixing, and a method of heating the emulsion after mixing, in order to make the temperature of the emulsion a predetermined temperature. Therefore, the method of mainly heating the water before mixing is preferably used, and the method of heating the polycarbonate organic solvent solution before mixing and the emulsion after mixing is used supplementarily.

The formation condition of the oil-in-water dispersion (O / W) emulsion is preferably such that the Weber number (We) in a static mixer is 2 × 10 ¹ to 2 × 10 ⁴ , and 5 × 10 ¹ to 1 × 10. ⁴ is more preferable, and 1 × 10 ^{2 to} 5 × 10 ³ is particularly preferable.
The Weber number (We) here is expressed by the following formula.
We = (D · u ² · ρ) / σs
(D represents the mixer inner diameter [m], u represents the average linear velocity of the fluid [m / s], ρ represents the continuous phase density [kg / m ³ ], and σs represents the interfacial tension [N / m].)

When the Weber number is smaller than 2 × 10 ^1, there is a problem that mixing is insufficient and the concentration of the residual organic solvent in the granule as a product is increased. When the Weber number is further reduced, the resin solution adheres and grows on the granulation tank wall, the stirring blade, and the like, thereby causing a trouble of generating a massive solid. On the other hand, when the Weber number is larger than 2 × 10 ⁴ , excessive energy is required to produce an emulsion, which is not preferable. Further, when the Weber number is increased more than necessary and the droplets in the emulsion become extremely fine, there arises a problem that causes a reduction in the bulk density of the granular material as a product.

  The volume ratio of the organic solvent solution to warm water for forming the emulsion varies depending on the type of polycarbonate resin, the molecular weight, the concentration in the organic solvent solution, etc., but usually the volume ratio is preferably 1: 0.2 to 5, More preferably, it is 1: 0.2-3. If the amount of warm water relative to the organic solvent solution is too small, it is not suitable because it becomes a water-in-oil dispersion type (W / O) emulsion rather than an oil-in-water dispersion type (O / W) emulsion. When the amount is too large, the slurry concentration is lowered during granulation, and when a kneader and a wet pulverizer are used, the pulverization mechanism does not work effectively. Moreover, the load of the process which isolate | separates a granular material from a slurry becomes large, and is not preferable.

  Any static mixer that forms an emulsion can be used as long as it can form an emulsion. Specifically, a static mixer (Noritake Co., Ltd.), a high mixer (Toray Engineering Co., Ltd.), T. T. et al. K. ROSS LPD mixer (Primics Co., Ltd.) and the like.

  The organic solvent solution and warm water emulsion are preferably fed continuously to a granulation vessel controlled at a constant temperature and a constant pressure. There is no particular limitation on the method of feeding the organic solvent solution and the hot water emulsion into the granulation tank, and the organic solvent solution and the hot water emulsion may be added dropwise by a dropping method, a direct charging method, or a shower method.

  The internal pressure of the granulation tank may be any pressure under pressure, atmospheric pressure or reduced pressure. However, although the organic solvent can be easily removed by reducing the pressure, the power of the blower or vacuum pump for reducing the pressure becomes excessive, which is disadvantageous in terms of energy. Moreover, the diffusion of the organic solvent in the generated particles is promoted by pressurization, and there is an advantage that the concentration of the residual organic solvent is reduced. However, excessive pressurization is advantageous from the viewpoint of apparatus cost and heating energy. Absent. Usually, conditions of pressurization, atmospheric pressure, or slightly reduced pressure for increasing the organic solvent recovery rate are applied. Specifically, the internal pressure of the granulation tank is preferably in the range of -0.02 to 0.3 MPa.

  As the granulation tank, a stirring layer having a stirring blade or a kneader (kneader) having a grinding mechanism can be used. The kneader is more preferably used because it is not necessary to prepare the slurry in advance.

  An example of a kneader is shown in the drawing. 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 for the ridges and protrusions for grinding, the height is about 3 to 20 mm, the pitch (interval between teeth) is about 3 to 20 mm, and the curvature radius of the tip is about 1 to 5 mm. The clearance between the wing and the barrel is preferably 1 to 50 mm.

  If the temperature of the granulation tank is too low, the evaporation of the organic solvent will slow down and the granulation processing capacity will decrease, or the dryness of the resin granules after granulation will deteriorate, and conversely it will be obtained if it is too high Since the bulk density of the resin granules tends to be too small, it is necessary to maintain the temperature in the granulation tank (water temperature) within the temperature range of T to T + 50 ° C., where the boiling point of the organic solvent is T (° C.). There is. The temperature range is preferably T + 2 ° C. to T + 45 ° C. For example, when methylene chloride is used as the organic solvent, the temperature is in the range of 40 to 90 ° C, and preferably in the temperature range of 42 to 85 ° C.

  It is not necessary to prepare granular materials in advance in the granulation tank even in the early stage of startup, and it is sufficient to continuously supply an emulsion of an organic solvent solution and warm water to warm water, and to the granulation tank wall, stirring blades, etc. Transfer to stable continuous granulation is possible without adhesion of resin mass.

  The weight ratio (polycarbonate / water) of the polycarbonate granules in the granulation tank to the warm water is preferably in the range of 0.05 to 1.0, particularly 0.07 to in terms of stirring and slurry handling and grinding efficiency. A range of 0.8 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 and the wet pulverizer decreases. It is preferable that the ratio between the polycarbonate resin granular material and the warm water is kept within the above range by adjusting the ratio between the polycarbonate resin solution supplied to the static mixer and the warm water when forming the emulsion.

  In the present invention, it is preferable to extract the water slurry of the polycarbonate granules produced in the granulation tank and pulverize with 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. 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 granulation tank and the one supplied to the next step is preferably in the range of 100: 1 to 1: 1, more preferably 50: It is 1-2: 1. If the rate of circulation to the granulation tank is too small, the particles formed in the granulation tank will be large, the load on the granulation tank and the wet pulverizer will be large, and the dryness of the resin granules will deteriorate. appear. On the other hand, when the rate of circulation to the granulation tank is too large, the liquid pump or wet pulverizer motor becomes excessive, which is disadvantageous in terms of energy.

  To recover the polycarbonate granules from the water slurry of the polycarbonate granules supplied to the next step, T + 20, where the water slurry is higher than the temperature at the time of granulation, and the boiling point of the organic solvent at atmospheric pressure is T (° C.). After adjusting the temperature to ℃ to T + 60 ℃, and preferably evaporating the solvent in hot water (about 85 to 95 ℃), the polycarbonate granules may be separated and recovered by means such as tilting, filtration, and centrifugation. The specific temperature of the slurry is, for example, a temperature range of 60 to 100 ° C. when methylene chloride is used as the organic solvent.

The warm water separated from the granular material by means of tilting, filtration, centrifugation, etc. is preferably used as warm water for forming an emulsion. By adopting this method, the thermal energy possessed by the hot water is effectively reused, resulting in a very efficient system.
Arbitrary stabilizers, additives, fillers and the like can be added to the polycarbonate granules thus obtained as required.

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]
As a granulation tank, a 50 liter stirring tank having two stages of three fouler blades with a blade diameter of 16 cm is provided as a wet pulverizer, equipped with a solution supply port, a steam inlet, a hot water inlet, a steam outlet and a slurry outlet. A disintegrator manufactured by Huxburna Zenoah Co., Ltd. was used.
A methylene chloride solution of a viscosity-average molecular weight of 25,000, which was synthesized and purified from bisphenol A and phosgene by a conventional method in a static mixer manufactured by Noritake Co., Ltd. with an inner diameter of 8 mm and a length of 155 mm (temperature: 35 ° C., concentration) 16 wt%) and warm water at 50 ° C. were introduced at a rate of 100 liters / hr, respectively, to obtain an oil-in-water dispersion (O / W) emulsion. At this time, the Weber number (We) in the static mixer was 189, and the temperature of the emulsion was 46 ° C.
The obtained emulsion was continuously supplied from the solution supply port to the above stirring tank stirred at 150 rpm under atmospheric pressure, containing 40 kg of 45 ° C. warm water slurry containing 10% by weight of polycarbonate granules, and at the same time pressure 0.3 MPa of water vapor was introduced at a rate of 18.5 kg / hr, and the internal temperature of the stirring tank was maintained at 45 ° C. In addition, the weight ratio (polycarbonate / warm water) of the polycarbonate granule and warm water in the granulation tank after 6 hours was 0.18.
While maintaining the water temperature at 45 ° C., the slurry is extracted from the slurry outlet of the stirring tank, wet-pulverized using a wet pulverizer, and while circulating 4 m ³ / hr of the slurry after wet pulverization to the granulation tank, A water slurry of 138 liters / 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 16% by weight.
The discharged water slurry is put into hot water maintained at 95 ° C. under atmospheric pressure with stirring, heated and degassed for 1 hour, and then the polycarbonate granules are separated by a centrifugal dehydrator and dried in hot air at 140 ° C. for 6 hours. Went. The methylene chloride content of the granular material after drying was 8.5 ppm, the average particle size was 1.2 mm, and the bulk density was 0.57 g / cm ³ .

[Example 2]
Using the same apparatus as in Example 1, the temperature of the hot water for producing the emulsion is 95 ° C., and the rate of steam supplied at a pressure of 0.3 MPa to maintain the internal temperature of the stirring tank at 45 ° C. is 11.6 kg / hr. Except for the above, polycarbonate granules were obtained in the same manner as in Example 1.
The Weber number (We) in the static mixer during the preparation of the emulsion was 174, the amount of the water slurry continuously discharged was 128 liters / hr, and the amount of residual methylene chloride in the polycarbonate granules of the discharged water slurry was The methylene chloride content of the dried granule was 2.1 ppm, the average particle size was 1.4 mm, and the bulk density was 0.46 g / cm ³ .

[Example 3]
Using the same apparatus as in Example 1, the temperature of the hot water stored in the stirring tank was set to 70 ° C., and the rate of steam with a pressure of 0.3 MPa supplied to maintain the internal temperature of the stirring tank at 70 ° C. was 32.5 kg. A polycarbonate granule was obtained in the same manner as in Example 1 except that / hr.
The Weber number (We) in the static mixer during the preparation of the emulsion was 189, the amount of the water slurry continuously discharged was 141 liters / hr, and the amount of residual methylene chloride in the polycarbonate granules of the discharged water slurry was The methylene chloride content of the granules after drying was 3.6 ppm, the average particle size was 1.6 mm, and the bulk density was 0.40 g / cm ³ .

[Example 4]
The same granulation tank and wet pulverizer as in Example 1 were used, except that the static mixer was a static mixer manufactured by Noritake Company Limited with an inner diameter of 16.1 mm and a length of 320 mm. Polycarbonate granules were obtained.
The Weber number (We) in the static mixer during the preparation of the emulsion was 23, the amount of water slurry continuously discharged was 138 liter / hr, and the amount of residual methylene chloride in the polycarbonate granules of the discharged water slurry was The methylene chloride content of the granules after drying was 61.4 ppm, the average particle size was 1.3 mm, and the bulk density was 0.62 g / cm ³ .

[Example 5]
The same granulation tank and wet pulverizer as in Example 1 were used, except that the static mixer was a static mixer manufactured by Noritake Co., Ltd. with an inner diameter of 4.0 mm and a length of 160 mm. Polycarbonate granules were obtained.
The Weber number (We) in the static mixer at the time of emulsion preparation was 1510, the amount of water slurry continuously discharged was 137 liters / hr, and the amount of residual methylene chloride in the polycarbonate granules of the discharged water slurry was The methylene chloride content of the granules after drying was 4.2 ppm, the average particle size was 1.2 mm, and the bulk density was 0.47 g / cm ³ .

[Example 6]
It has a solution supply port, a water vapor inlet, a hot water inlet, a steam outlet and a 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 pulverizer ) Disintegrator made.
A methylene chloride solution of a viscosity-average molecular weight of 25,000, which was synthesized and purified from bisphenol A and phosgene by a conventional method in a static mixer manufactured by Noritake Co., Ltd. with an inner diameter of 8 mm and a length of 155 mm (temperature: 35 ° C., concentration) 16% by weight) and 50 ° C. warm water were introduced at a rate of 100 liters / hr and 50 liters / hr, respectively, to obtain an oil-in-water dispersion (O / W) emulsion. At this time, the Weber number (We) in the static mixer was 107, and the temperature of the emulsion was 43 ° C.
The emulsion was continuously supplied from the solution supply port to the above kneader containing 40 kg of warm water of 45 ° C. and stirred at 150 rpm under atmospheric pressure, and at the same time, steam at a pressure of 0.3 MPa was supplied at 18.8 kg / hr. Introduced at a rate, the internal temperature of the kneader was maintained at 45 ° C. In addition, the weight ratio (polycarbonate / hot water) of the polycarbonate granular material in the kneader after 6 hours and warm water was 0.32.
The water temperature was maintained at 45 ° C., the slurry was extracted from the slurry outlet of the kneader, wet pulverized using a wet pulverizer, and 2 m ³ / hr of the slurry after wet pulverization was circulated through the kneader to 89 liter / The water slurry of hr was continuously discharged, and at the same time, the evaporated methylene chloride was led from the vapor outlet to the condenser and separated from the accompanying water, and methylene chloride was recovered. The amount of residual methylene chloride in the polycarbonate granules of the discharged water slurry was 17% by weight.
The discharged water slurry is put into hot water maintained at 95 ° C. under atmospheric pressure with stirring, heated and degassed for 1 hour, and then the polycarbonate granules are separated by a centrifugal dehydrator and dried in hot air at 140 ° C. for 6 hours. Went. The dried granular material had a methylene chloride content of 11.7 ppm, an average particle size of 1.3 mm, and a bulk density of 0.58 g / cm ³ .

[Example 7]
Using the same apparatus as in Example 6, the temperature of the hot water for producing the emulsion is 95 ° C., and the rate of steam supplied at a pressure of 0.3 MPa to maintain the internal temperature of the stirring tank at 45 ° C. is 15.5 kg / hr. Except for the above, polycarbonate granules were obtained in the same manner as in Example 1.
The Weber number (We) in the static mixer at the time of emulsion preparation was 100, the amount of water slurry discharged continuously was 83 liters / hr, and the amount of residual methylene chloride in the polycarbonate granules of the discharged water slurry was The methylene chloride content of the granules after drying was 6.9 ppm, the average particle size was 1.5 mm, and the bulk density was 0.51 g / cm ³ .

[Example 8]
Using the same kneader and static mixer as in Example 6 and using a slurry pump manufactured by Sanwa Hydrotech Co., Ltd. instead of a wet pulverizer, the temperature of hot water for preparing the emulsion was 80 ° C., and the internal temperature of the kneader was A polycarbonate granule was obtained in the same manner as in Example 6 except that the steam supplied at a pressure of 0.3 MPa to maintain the temperature at 45 ° C was set to 16.7 kg / hr.
The Weber number (We) in the static mixer during the preparation of the emulsion was 102, the amount of the water slurry continuously discharged was 84 liters / hr, and the amount of residual methylene chloride in the polycarbonate granules of the discharged water slurry was The methylene chloride content of the granules after drying was 107.4 ppm, the average particle size was 2.8 mm, and the bulk density was 0.55 g / cm ³ .

[Example 9]
Using the same apparatus as in Example 1, the pressure of the stirring tank was set to 0.05 MPa, the temperature of the hot water stored in the stirring tank was set to 55 ° C., and the pressure supplied to maintain the internal temperature of the stirring tank at 55 ° C. was 0. A polycarbonate granule was obtained in the same manner as in Example 1 except that the rate of steam at 3 MPa was 22.3 kg / hr.
The Weber number (We) in the static mixer at the time of preparing the emulsion was 189, the amount of the water slurry continuously discharged was 138 liter / hr, and the amount of residual methylene chloride in the polycarbonate granules of the discharged water slurry was The methylene chloride content of the granule after drying was 5.1 ppm, the average particle size was 1.3 mm, and the bulk density was 0.49 g / cm ³ .

[Example 10]
As a granulation tank, a 250 liter stirring tank equipped with a solution supply port, a steam inlet, a hot water inlet, a steam outlet, and a slurry outlet, and having two stages of 3 fouler blades with a blade diameter of 28 cm is used as a wet pulverizer. A disintegrator manufactured by Huxburna Zenoah Co., Ltd. was used.
A methylene chloride solution (temperature 35 ° C., concentration) of a viscosity-average molecular weight 25,000 polycarbonate synthesized and purified from bisphenol A and phosgene by a conventional method in a static mixer manufactured by Noritake Co., Ltd. with an inner diameter of 5 mm and a length of 200 mm. 16% by weight) and warm water at 50 ° C. were introduced at a rate of 300 liters / hr, respectively, to obtain an oil-in-water dispersion type (O / W) emulsion. At this time, the Weber number (We) in the static mixer was 7000, and the temperature of the emulsion was 46 ° C.
The obtained emulsion was continuously supplied from the solution supply port to the above stirring tank that was stirred at 120 rpm under atmospheric pressure, containing 130 kg of 45 ° C. warm water slurry containing 10% by weight of polycarbonate granules, and at the same time pressure 0.3 MPa of water vapor was introduced at a rate of 50.6 kg / hr, and the internal temperature of the stirring tank was maintained at 45 ° C. In addition, the weight ratio (polycarbonate / warm water) of the polycarbonate granule in the granulation tank after 6 hours and warm water was 0.19.
While maintaining the water temperature at 45 ° C., the slurry is extracted from the slurry outlet of the stirring tank, wet-pulverized using a wet pulverizer, and while circulating 10 m ³ / hr of the slurry after wet pulverization to the granulation tank, A water slurry of 407 liters / 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 13% by weight.
The discharged water slurry is put into hot water maintained at 95 ° C. under atmospheric pressure with stirring, heated and degassed for 1 hour, and then the polycarbonate granules are separated by a centrifugal dehydrator and dried in hot air at 140 ° C. for 6 hours. Went. The dried granular material had a methylene chloride content of 3.3 ppm, an average particle size of 1.2 mm, and a bulk density of 0.37 g / cm ³ .

[Example 11]
Wet grinding using a 250 liter jacketed agitation tank equipped with a solution supply port, a steam inlet, a hot water inlet, a steam outlet and a slurry outlet as a granulation tank and having two stages of three fouller blades with a blade diameter of 28 cm A disintegrator manufactured by Huxburna Zenoah Co., Ltd. was used as the machine.
A methylene chloride solution (temperature 35 ° C.) of a viscosity-average molecular weight 25,000 polycarbonate synthesized and purified from bisphenol A and phosgene by a conventional method in a static mixer manufactured by Noritake Co., Ltd. with an inner diameter of 16.1 mm and a length of 320 mm. , Concentration of 16% by weight) and hot water separated from the granular material by a centrifugal dehydrator were introduced at a rate of 300 liters / hr, respectively, to form an oil-in-water dispersion (O / W) emulsion.
The obtained emulsion was continuously supplied from the solution supply port to the above stirring tank that was stirred at 120 rpm under atmospheric pressure, containing 130 kg of 45 ° C. warm water slurry containing 10% by weight of polycarbonate granules, and at the same time pressure 0.3 MPa of water vapor was introduced at a rate to maintain the internal temperature of the stirring tank at 45 ° C.
While maintaining the water temperature at 45 ° C., the slurry is extracted from the slurry outlet of the stirring tank, wet-pulverized using a wet pulverizer, and while circulating 10 m ³ / hr of the slurry after wet pulverization to the granulation tank, The water slurry was continuously discharged so that the level of the jacketed agitation tank was constant, and at the same time, the evaporated methylene chloride was separated from the entrained water through the steam outlet to the condenser, and methylene chloride was recovered.
The discharged water slurry was put into hot water maintained at 95 ° C. under atmospheric pressure with stirring, heated and degassed for 1 hour, and then the polycarbonate granules were separated by a centrifugal dehydrator.
The warm water separated from the granular material was introduced into the jacket of a jacketed stirring tank, and after heat exchange, it was used as warm water to be mixed with the polycarbonate resin organic solvent solution.
After 6 hours, the temperature of the hot water mixed with the polycarbonate resin organic solvent solution was 52 ° C., the Weber number (We) in the static mixer at this time was 215, the temperature of the emulsion was 47 ° C., and the pressure introduced into the granulation tank was 0 .3 MPa water vapor is 21.9 kg / hr, the weight ratio of polycarbonate granules in the granulation tank to warm water (polycarbonate / warm water) is 0.20, and the amount of residual methylene chloride in the polycarbonate granules in the discharged water slurry is It was 15% by weight.
The polycarbonate granules were dried with hot air at 140 ° C. for 6 hours. The dried granules had a methylene chloride content of 7.0 ppm, an average particle size of 1.2 mm, and a bulk density of 0.56 g / cm ³ .

[Comparative Example 1]
Using the same granulation tank as in Example 1, without using a static mixer, using a slurry pump manufactured by Sanwa Hydrotech Co., Ltd. instead of a wet pulverizer, synthesized from bisphenol A and phosgene by a conventional method, A purified methylene chloride solution of polycarbonate having a viscosity average molecular weight of 25,000 (temperature: 35 ° C., concentration: 16% by weight) was continuously added to the stirring tank containing 40 kg of warm water of 45 ° C. and stirred at 150 rpm under atmospheric pressure. Were supplied at a rate of 100 liters / hr from the solution supply port, and at the same time, steam at a pressure of 0.3 MPa and hot water at 50 ° C. were introduced at a rate of 18.4 kg / hr and 100 liters / hr, respectively. The adhesion to the stirring blade was severe, and operation was impossible.

[Comparative Example 2]
The same granulating tank and wet pulverizer as in Example 1 were used, except that the static mixer was a static mixer manufactured by Noritake Co., Ltd. having an inner diameter of 27.2 mm and a length of 550 mm. Polycarbonate granules were obtained.
The Weber number (We) in the static mixer at the time of emulsion preparation was 5, the amount of water slurry discharged continuously was 138 liter / hr, and the amount of residual methylene chloride in the polycarbonate granules of the discharged water slurry was The methylene chloride content of the granules after drying was 1630 ppm, the average particle size was 1.6 mm, and the bulk density was 0.62 g / cm ³ .

  The polycarbonate resin obtained by this invention is shape | molded and used according to various uses, such as a film, a sheet | seat, and a molded article.

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. Spacing between teeth of protrusions and ridges R _{1 to} R ₃ . Curvature radii of the protrusion tip and the protrusion tip h _{1 to} h ₃ . Height of protrusion and ridge

Claims (5)

The polycarbonate resin organic solvent solution and warm water are mixed with a static mixer under pressure to form an oil-in-water dispersion (O / W) emulsion, and the boiling point of the organic solvent at atmospheric pressure is T (° C.). A method of continuously supplying to a granulation tank maintained at T ° C. to T + 50 ° C. and removing an organic solvent to produce a polycarbonate granule having a Weber number (We) of 2 × 10 ^{1 in} a static mixer. A continuous production method of polycarbonate granule, characterized in that it is ˜2 × 10 ⁴ .   The process for continuously producing a polycarbonate granule according to claim 1, wherein the temperature of the oil-in-water dispersion (O / W) emulsion is in the range of T ° C to T + 80 ° C.   The polycarbonate granule according to claim 1 or 2, wherein at least a part of the produced polycarbonate granule is extracted, pulverized by a wet pulverizer, and then circulated into a granulation tank to produce the polycarbonate granule according to claim 1 or 2. Method.   The continuous manufacturing method of the polycarbonate granular material of any one of Claims 1-3 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 granulation tank.   The water slurry of the polycarbonate granules obtained in claims 1 to 4 is hydrothermally treated at T + 20 ° C. to T + 60 ° C., then dehydrated to separate and recover the polycarbonate granules, and the hot water separated from the granules is emulsified. The continuous manufacturing method of the polycarbonate granular material of any one of Claims 1-4 used as warm water for formation.

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