KR102530453B1 - Method for preparing granule polycarbonate - Google Patents

Abstract

The present invention relates to a method for producing granular polycarbonate. According to the present invention, granular polycarbonate particles having excellent physical properties can be obtained without using a stabilizer or a surfactant.

Description

Manufacturing method of granule polycarbonate {METHOD FOR PREPARING GRANULE POLYCARBONATE}

The present invention relates to a method for producing granular polycarbonate.

Polycarbonate is one of engineering plastics and is widely used in the plastics industry. The polycarbonate is excellent in transparency, impact resistance, mechanical strength, heat resistance, etc., and is applied in a wide range of fields such as transparent sheets, automobile bumpers, and optical disks.

These polycarbonates are usually prepared through a method of reacting a divalent aromatic hydroxy compound with phosgene or an exchange method of reacting a divalent aromatic hydroxy compound with a carbonic acid diester.

In the polycarbonate polymerization product prepared by the above method, in addition to the desired polycarbonate, catalyst components such as methylene chloride (CH ₂ Cl ₂ ) and triethylamine (TEA), which are organic solvents commonly used in polycarbonate production, and sodium chloride, sodium carbonate and Impurities such as salt components are present. Therefore, after the polycarbonate polymerization process, a series of purification processes are performed to remove impurities present in the polymer solution.

The polycarbonate polymer that has undergone the purification process is shaped into a powder form, flake form, granule form, etc. while undergoing a solvent removal process, and is finally made into a pellet form by thermal extrusion.

However, in the case of powder form, there is a problem of scattering during operation, and in the case of flake form, the weight compared to the volume is remarkably small, so it is inefficient in producing alloy products with other polymers, so it is usually processed into pellets and used. However, since it is exposed to high-temperature heat in order to be processed into pellets, there is a problem in that the physical properties of the original polycarbonate are lowered.

In order to solve this problem, a lot of research is being conducted to prepare polycarbonate having a granular form of high bulk density similar to pellets during the solvent removal process without heat exposure.

As a conventional purification method, a method using an antisolvent is described in US Patent No. 5196507A, US Patent No. 5726223A and the like. These documents disclose a method of obtaining solvent-free polycarbonate particles using an anti-solvent that is miscible with the solvent but does not dissolve the polycarbonate. However, according to the method disclosed in the above documents, there are problems such as the need to use a large amount of anti-solvent and the use of a stabilizer to obtain spherical polycarbonate particles.

US Patent No. 4546172A discloses a method for obtaining polymer particles using only water without an anti-solvent. However, in the case of this method, there is a problem in that the process time is long and the size of the particles is not uniform, so that an additional process such as grinding is required.

In addition, there is a method of producing polycarbonate particles by removing the solvent in a short time by methods such as spray drying or high-temperature steam injection, but the polycarbonate particles obtained by the above method have many internal voids, so that the bulk density of the particles is low. There is a downside problem.

US Patent No. 5196507A US Patent No. 5726223A US Patent No. 4546172A

An object of the present invention is to provide a method for producing granular polycarbonate, capable of obtaining granular polycarbonate particles having excellent physical properties without using a stabilizer or a surfactant.

In order to achieve the above object, the present invention

preparing a mixed solution by mixing a polymerization solution containing polycarbonate and an organic solvent with an anti-solvent solution containing water and a nitrile-based anti-solvent;

heating the mixed solution to remove the organic solvent; and

Drying or filtering the mixed solution to obtain granular polycarbonate particles,

A method for producing granular polycarbonate is provided.

According to the present invention, the organic solvent present in the polymerization reaction solution after the polymerization process of polycarbonate can be effectively removed. In particular, since the purification process does not have to be performed under high temperature and high vacuum conditions, energy consumption required for the purification process can be reduced.

In addition, spherical granular polycarbonate particles having excellent physical properties in terms of bulk density or particle size range can be obtained without using a surfactant, stabilizer, or polycarbonate powder for nucleation.

In addition, according to the production method of the present invention, since the obtained granular polycarbonate is not exposed to high temperatures, there is no concern about deterioration of the inherent properties of polycarbonate due to high temperature heat, and it has an appropriate particle diameter range, so it does not scatter into fine powder and has good flowability. There are advantages to the environment.

1 is a SEM photograph of polycarbonate granules obtained according to an embodiment of the present invention.

Terms used in this specification are only used to describe exemplary embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly dictates otherwise. In this specification, terms such as "comprise", "comprise" or "having" are intended to indicate that there is an embodied feature, step, component, or combination thereof, but one or more other features or steps; It should be understood that the presence or addition of components, or combinations thereof, is not previously excluded.

Since the present invention can have various changes and various forms, specific embodiments will be exemplified and described in detail below. However, it should be understood that this is not intended to limit the present invention to the specific disclosed form, and includes all modifications, equivalents, and substitutes included in the spirit and scope of the present invention.

Hereinafter, a method for manufacturing granular polycarbonate according to specific embodiments of the present invention will be described in more detail.

According to one embodiment of the present invention, preparing a mixed solution by mixing a polymerization solution containing polycarbonate and an organic solvent with an anti-solvent solution containing water and a nitrile-based anti-solvent; heating the mixed solution to remove the organic solvent; and drying or filtering the mixed solution to obtain granular polycarbonate.

Specifically, the manufacturing method of the granular polycarbonate of the present invention will be described step by step.

First, a mixed solution is prepared by mixing a polymerization solution containing polycarbonate and an organic solvent with an anti-solvent solution containing water and a nitrile-based anti-solvent.

In the present invention, the polymerization method of polycarbonate is not particularly limited, and can be directly prepared according to known polymerization methods of general polycarbonate resins using a divalent hydroxy compound and a carbonate precursor as starting materials.

The divalent hydroxy compound and the carbonate precursor are not particularly limited as long as they are used for producing polycarbonate.

More specifically, the divalent hydroxy compounds include bisphenol A, 1,1-bis (4-hydroxyphenyl) ethane, bis (4-hydroxyphenyl) methane, bis (4-hydroxyphenyl) ether, bis (4-hydroxyphenyl)sulfone, bis(4-hydroxyphenyl)sulfoxide, bis(4-hydroxyphenyl)sulfide, bis(4-hydroxyphenyl)ketone, 2,2-bis(4-hydroxy Phenyl) butane, 1,1-bis (4-hydroxyphenyl) cyclohexane, 2,2-bis (4-hydroxy-3,5-dibromophenyl) propane, 2,2-bis (4-hydroxy hydroxy-3,5-dichlorophenyl)propane, 2,2-bis(4-hydroxy-3-bromophenyl)propane, 2,2-bis(4-hydroxy-3-chlorophenyl)propane, 2, 2-bis(4-hydroxy-3-methylphenyl)propane, 2,2-bis(4-hydroxy-3,5-dimethylphenyl)propane, 1,1-bis(4-hydroxyphenyl)-1- phenylethane, bis(4-hydroxyphenyl)diphenylmethane, or α,ω-bis[3-(ο-hydroxyphenyl)propyl]polydimethylsiloxane, and the like, any one or a mixture of two or more thereof. this can be used

In addition, as the carbonate precursor, dimethyl carbonate, diethyl carbonate, dibutyl carbonate, dicyclohexyl carbonate, diphenyl carbonate, ditoryl carbonate, bis(chlorophenyl) carbonate, di-m-cresyl carbonate, dinaphthyl carbonate, bis(diphenyl) carbonate, phosgene, triphosgene, diphosgene, bromophosgene, or bishaloformate, and the like, and any one or a mixture of two or more of these may be used.

As the polymerization method, for example, an interfacial polymerization method may be used, and in this case, the polymerization reaction is possible at normal pressure and low temperature, and the molecular weight is easily controlled. The interfacial polymerization is usually performed in the presence of a salt component and an organic solvent.

Materials used for the interfacial polymerization are not particularly limited as long as they can be used for polymerization of polycarbonate, and the amount thereof may be adjusted as necessary.

As the salt component, for example, an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide or an amine compound such as pyridine may be used.

The organic solvent is not particularly limited as long as it is a solvent commonly used for polymerization of polycarbonate, and for example, halogenated hydrocarbons such as methylene chloride and chlorobenzene may be used.

In addition, the interfacial polymerization is a reaction such as triethylamine, tetra-n-butylammonium bromide, tetra-n-butylphosphonium bromide, etc., tertiary amine compounds, quaternary ammonium compounds, quaternary phosphonium compounds, etc. Accelerators may additionally be used.

Therefore, in the polycarbonate polymerization product prepared by the above method, in addition to the desired polycarbonate, impurities such as catalyst components such as organic solvents methylene chloride (MC) and triethylamine (TEA) and salt components such as sodium chloride and sodium carbonate are present. exist.

According to one embodiment of the present invention, before performing the step of removing the organic solvent, the step of removing the catalyst component and the salt component included in the polymerization reaction product may be additionally performed. The step of removing the catalyst component and the salt component may be performed by a conventional method used in the art to which the present invention belongs, and is not particularly limited. For example, a polymerization solution containing polycarbonate and an organic solvent and an impurity solution in which other components such as a catalyst and a salt component are dissolved may be separated by a difference in density using a centrifugal separator.

In the specification of the present invention, the catalyst component and the salt component are removed and separated from the polycarbonate polymerization reaction product as described above, and the separated solution containing substantially only the polycarbonate resin and the organic solvent is referred to as "polymerization reaction solution". do.

The polycarbonate polymerization solution typically contains about 5 to about 20% by weight of the polycarbonate resin and about 80 to about 95% by weight of the organic solvent based on the total weight of the polymerization reaction solution.

The present invention may be a granulation process for preparing a polycarbonate resin in the form of a solution into polycarbonate particles in the form of granules by removing the organic solvent contained in the polycarbonate polymerization reaction solution as described above.

A mixed solution is prepared by mixing the above polycarbonate polymerization reaction solution and an anti-solvent solution containing water and a nitrile-based anti-solvent.

Conventionally, a method of using an alcohol-based solvent such as hexane, heptane, methanol, ethanol, propanol, or isopropanol, a ketone solvent such as acetone or methyl ethyl ketone, or ethyl acetate as an anti-solvent in a polycarbonate purification process is known. However, when using the anti-solvent as described above, a large amount of the anti-solvent must be used. In addition, there is a disadvantage in that a surfactant or a stabilizer must be added for granulation of polycarbonate, or polycarbonate powder must be additionally added to assist in nucleation and growth processes.

In the present invention, when a mixed solvent of water and a nitrile antisolvent is used, it is not necessary to add a surfactant, stabilizer, or polycarbonate powder for granulation of polycarbonate, and granular polycarbonate having excellent physical properties even with a small amount of antisolvent Noticing that carbonates could be obtained led to the present invention.

The nitrile antisolvent is acetonitrile, propionitrile, butyronitrile, valeronitrile, caprylonitrile, heptanenitrile, cyclopentane carbonitrile, cyclohexane carbonitrile, 2-fluorobenzonitrile, 4-fluorobenzo It may be nitrile, difluorobenzonitrile, trifluorobenzonitrile, phenylacetonitrile, 2-fluorophenylacetonitrile, or 4-fluorophenylacetonitrile, but is not limited thereto. Preferably, acetonitrile can be used.

According to one embodiment of the present invention, the anti-solvent solution may be mixed in a weight equal to or less than that of the polymerization solution, more specifically, the weight ratio of the anti-solvent solution and the polymerization solution (anti-solvent solution : polymerization reaction solution) may be 2:8 to 5:5, or 3:7 to 5:5, or 4:6 to 5:5. If the content of the anti-solvent solution is too small beyond the above-mentioned range, it may not be granulated and agglomerate into one lump, conversely, if it is too large, it may be powdered, and in actual production, the production rate is lowered and uneconomical. There may be, and from this point of view, it is preferable to have the above weight ratio range.

According to one embodiment of the present invention, the antisolvent solution contains 5% by weight or more, or 10% by weight or more, or 20% by weight or more of the nitrile antisolvent based on the total weight of the antisolvent solution (water + antisolvent). , or 25% by weight or more, or 30% by weight or more, and may include 40% by weight or less, or 38% by weight or less, or 35% by weight or less. If the content of the nitrile-based antisolvent is too small, amorphous particles (polycarbonate particles having a long axis of 150 mm or more) may be produced or agglomerate into one lump. It can be manufactured, and from this point of view it is preferable to have the above weight range.

Also, according to one embodiment of the present invention, the nitrile-based anti-solvent may be included in an amount of 90 to 200 parts by weight based on 100 parts by weight of the polycarbonate included in the polycarbonate polymerization solution. If the amount of the nitrile-based antisolvent is less than 90 parts by weight, amorphous particles may be produced or lumped together, and conversely, if the amount of the nitrile-based antisolvent exceeds 200 parts by weight and is too large, granules are not formed and powder It can be manufactured in a form, and from this point of view it is preferable to have the above weight range.

In one embodiment of the present invention, the anti-solvent solution consists of only water and a nitrile-based anti-solvent, and does not include other anti-solvents other than the nitrile-based anti-solvent as anti-solvents.

A method of adding a surfactant, stabilizer or additional polycarbonate powder for granulation of polycarbonate has been conventionally used, but when granules are prepared by adding a surfactant or stabilizer, these inputs must be completely removed, making the process cumbersome. , if not completely removed, there is a problem that the physical properties of polycarbonate, in particular, the transparency is lowered.

In addition, when the polycarbonate powder is introduced for nucleation, a powder input process is added, which is not preferable in terms of process economy, and the powder has poor flowability, so it is difficult to construct a transfer system.

Meanwhile, in one embodiment of the present invention, since a surfactant, a stabilizer or additional polycarbonate powder for granulation of polycarbonate is not added, the above problems that may occur due to the additional addition of these can be prevented.

The method of mixing the polycarbonate polymerization solution and the anti-solvent solution is not particularly limited, and the polycarbonate polymerization solution is first put into a container and the anti-solvent solution is added, or the anti-solvent solution is first put into the container and the polycarbonate polymerization solution is first added to the container. Any method, such as a method of introducing a carbonate polymerization reaction solution or a method of simultaneously introducing the polycarbonate polymerization reaction solution and an anti-solvent solution, may be used.

In addition, the mixing temperature is not particularly limited, and may be performed in the range of room temperature (25 ± 2 ℃).

Next, the organic solvent is removed by heating the mixed solution.

The heating may be performed such that the temperature of the mixed solution is 40 to 70 °C or 40 to 60 °C. If the heating temperature is too low, less than 40 ° C, removal of the organic solvent may not be sufficient, and if the heating temperature is too high, exceeding 70 ° C, a large number of pores are generated inside the granules or the size of the pores increases, causing a decrease in bulk density. Since it can be, the range of the heating temperature is preferably the above-mentioned range.

In addition, the heating may be performed for 30 to 250 minutes or 30 to 200 minutes. If the heating time is too short, less than 30 minutes, removal of the organic solvent may not be sufficient, and if the heating time is too long, exceeding 250 minutes, a large amount of fine powder may be generated, which may be disadvantageous in terms of yield and economy during production. .

In addition, the heating may be performed by a method such as a water bath, a jacket, a heating band, or a coil jacket, but the present invention is not limited thereto.

According to one embodiment of the present invention, it may be preferable to heat the mixed solution while stirring at a constant speed, for example, 80 to 900 rpm, or 100 to 800 rpm during heating.

By the heating process, the organic solvent contained in the polycarbonate polymerization solution may be removed in an amount of 80 wt% or more, or 84 wt% or more, and about 90 wt% or less, or about 88 wt% or less, based on the initial 100 wt% content. there is. When the removal weight of the organic solvent is less than 80%, granules cannot be formed, and polycarbonate in a lumpy or sticky form is obtained. will create a fraction. Therefore, the step of removing the organic solvent by heating may be performed to the extent that 80 to 90% of the organic solvent is removed.

The remaining organic solvent may be removed by filtration or drying in a later step.

Next, the mixed solution from which 80% by weight or more of the organic solvent has been removed is dried or filtered to remove the remaining water and the nitrile-based antisolvent to obtain granular polycarbonate.

The drying may be performed such that the temperature of the mixed solution is 80 to 150 °C or 100 to 150 °C. If the drying temperature is too low, less than 80 ° C, the organic solvent and anti-solvent may not be completely removed, and if the drying temperature is too high, exceeding 150 ° C, a change in physical properties may occur around the glass transition temperature of polycarbonate. Therefore, the range of the drying temperature is preferably the above range.

Meanwhile, the drying time may be about 60 to about 600 minutes in consideration of process efficiency, but is not limited thereto.

In addition, as long as the drying method is commonly used as a drying process, it may be selected and used without limitation in its configuration.

In addition, as long as the filtration method is commonly used, it may be selected and used without limitation in its configuration.

Granular polycarbonate may be obtained by the above method, and the obtained granular polycarbonate may have a bulk density of 0.40 to 0.70 g/cm ³ as measured by the ASTM D1895 method.

More specifically, the granular polycarbonate has a bulk density of 0.40 g / cm ³ measured by the ASTM D1895 method. or more, or 0.42 g/cm ³ or more, or 0.45 g/cm ³ or more, or 0.50 g/cm ³ may be ideal As such, the granular polycarbonate obtained by the production method of the present invention has excellent productivity due to its high bulk density, and can exhibit excellent compatibility when compounded with other polymers to form a polymer alloy.

The upper limit of the bulk density is not particularly limited, but is, for example, 0.70 g/cm ³ or less, or 0.65 g/cm ³ or less, or 0.60 g/cm ³ or less, or 0.58 g/cm ³ or less.

In addition, the average particle diameter of the granular polycarbonate may be 0.3 to 10 mm.

More specifically, the average particle diameter of the granular polycarbonate was 0.3 mm greater than or equal to 0.5 mm greater than or equal to 0.7 mm In spite of being ideal; 10mm or less, or 8 mm or less, or 7 mm or less, or 6 mm may be below.

The average particle diameter of the granular polycarbonate is obtained by selecting 20 granule particles from each of 10 randomly selected areas using SEM images, measuring the length of the long axis of the selected granule particles, and obtaining an average value thereof, or using the image j program. It can be measured by measuring the length of the long axis of 5000 or more granular particles through a method of obtaining the average value.

The granular polycarbonate obtained may also be substantially spherical.

In addition, the residual amount of methylene chloride in the granular polycarbonate may be 50 ppm or less, or 30 ppm or less, or 10 ppm or less, so that all methylene chloride may be substantially removed.

As described above, according to the method for producing granular polycarbonate of the present invention, the organic solvent present in the polymerization reaction product can be effectively removed, and spherical granular polycarbonate particles having excellent physical properties in terms of bulk density or particle size range can be obtained. there is.

Hereinafter, preferred embodiments of the present invention will be described in detail. However, these examples are only intended to illustrate the present invention, and the scope of the present invention will not be construed as being limited by these examples.

<Example>

Example 1

A polymerization reaction was carried out by a conventional polycarbonate polymerization process by interfacial polymerization using bisphenol A and phosgene as starting materials and methylene chloride as a solvent. The polymerization reaction product was centrifuged to prepare a polymerization reaction solution containing polycarbonate and methylene chloride (including 17 wt% of polycarbonate and 83 wt% of methylene chloride in the polymerization reaction solution).

3,500 g of the above polymerization reaction solution and 3,500 g of an anti-solvent solution of water and acetonitrile (80 wt % of water, 20 wt % of acetonitrile) were mixed at room temperature, and at a temperature of 50° C. for 50 minutes at a rate of 1.5 to 3 m/s. The mixture was stirred to remove methylene chloride up to 85 wt%.

Next, the polycarbonate was dried in an oven set at a temperature of 150 DEG C for 120 minutes to obtain granular polycarbonate.

Example 2

The same polycarbonate polymerization reaction solution as in Example 1 was prepared.

4,200 g of the above polymerization reaction solution and 2,800 g of an anti-solvent solution of water and acetonitrile (75 wt % of water, 25 wt % of acetonitrile) were mixed at room temperature, and at a temperature of 50° C. for 60 minutes at a speed of 1.5 to 3 m/s. The mixture was stirred to remove methylene chloride up to 85wt%.

Subsequent procedures were the same as in Example 1 to obtain granular polycarbonate.

Example 3

The same polycarbonate polymerization reaction solution as in Example 1 was prepared.

4,200 g of the polymerization reaction solution and 2,800 g of an anti-solvent solution of water and acetonitrile (67.5 wt % of water, 32.5 wt % of acetonitrile) were mixed at room temperature, and 1.5 to 3 m/s was applied at 50° C. for 60 minutes. By stirring at a speed of methylene chloride was removed up to 85wt%.

Subsequent procedures were the same as in Example 1 to obtain granular polycarbonate.

Example 4

The same polycarbonate polymerization reaction solution as in Example 1 was prepared.

3,500 g of the above polymerization reaction solution and 3,500 g of an anti-solvent solution of water and acetonitrile (70 wt % of water, 30 wt % of acetonitrile) were mixed at room temperature, and at a temperature of 50° C. for 50 minutes at a speed of 1.5 to 3 m/s. The mixture was stirred to remove methylene chloride up to 85wt%.

Subsequent procedures were the same as in Example 1 to obtain granular polycarbonate.

Comparative Example 1

In Example 1, polycarbonate particles were obtained in the same manner as in Example 1, except that a solution containing 70 wt% of water and 30 wt% of ethyl acetate was used as the antisolvent solution.

Comparative Example 2

In Example 1, polycarbonate particles were obtained in the same manner as in Example 1, except that a solution containing 70 wt% of water and 30 wt% of acetone was used as the antisolvent solution.

Comparative Example 3

In Example 1, polycarbonate was obtained in the same manner as in Example 1, except that a solution containing 70 wt% of water and 30 wt% of hexane was used as the antisolvent solution. The obtained polycarbonate was agglomerated and did not have a particle shape.

Comparative Example 4

In Example 1, polycarbonate was obtained in the same manner as in Example 1, except that a solution containing 100 wt% of water was used as the anti-solvent solution. The obtained polycarbonate was agglomerated and did not have a particle shape.

<Experimental example>

The physical properties of the polycarbonate particles obtained in Examples and Comparative Examples were evaluated in the following manner, and the results are shown in Table 1 below.

(1) Average particle diameter: 20 granular polycarbonates were randomly selected from each of 10 random areas in the SEM image (magnified 30 times), and the length of the long axis of the selected granule polycarbonate was measured to obtain an average value.

In addition, the SEM image of Example 4 is shown in FIG.

(2) Bulk density: measured according to the ASTM D1895 method.

average particle diameter
(Unit: mm) bulk density
(Unit: g/cm ³ ) Example 1 4.45 0.62 Example 2 5.21 0.58 Example 3 2.38 0.57 Example 4 0.78 0.43 Comparative Example 1 Differential less than 0.2 mm not measurable Comparative Example 2 Differential less than 0.2 mm not measurable Comparative Example 3 not measurable not measurable Comparative Example 4 not measurable not measurable

Referring to Table 1, in the case of Examples 1 to 4 in which the organic solvent was removed using an anti-solvent solution containing water and a nitrile-based anti-solvent and a drying process was performed according to the preparation method of the present invention, spherical granular polycarbonate was obtained, 0.43 g/cm ³ The above excellent bulk density was exhibited. However, in the case of Comparative Examples 1 to 4 using only a conventional solvent or water as an anti-solvent solution, granular polycarbonate particles could not be obtained.

Claims (10)

preparing a mixed solution by mixing a polymerization solution containing polycarbonate and an organic solvent with an anti-solvent solution containing water and a nitrile-based anti-solvent;
heating the mixed solution to remove the organic solvent; and
Drying or filtering the mixed solution to obtain granular polycarbonate,
The nitrile antisolvent is acetonitrile, propionitrile, butyronitrile, valeronitrile, caprylonitrile, heptanenitrile, cyclopentane carbonitrile, cyclohexane carbonitrile, 2-fluorobenzonitrile, 4-fluorobenzo At least one selected from the group consisting of nitrile, difluorobenzonitrile, trifluorobenzonitrile, phenylacetonitrile, 2-fluorophenylacetonitrile, and 4-fluorophenylacetonitrile,
Method for producing granular polycarbonate.
delete According to claim 1,
The antisolvent solution and the polymerization solution are mixed in a weight ratio of 2:8 to 5:5, a method for producing granular polycarbonate.
According to claim 1,
The antisolvent solution comprises the nitrile-based antisolvent in an amount of 5 to 40% by weight based on the total weight of the antisolvent solution.
According to claim 1,
The organic solvent is a method for producing a granular polycarbonate containing methylene chloride.
According to claim 1,
The heating is performed such that the temperature of the mixed solution is 40 to 70 ° C., a method for producing granular polycarbonate.
According to claim 1,
The drying is performed such that the temperature of the mixed solution is 80 to 150 ° C., a method for producing granular polycarbonate.
According to claim 1,
The granular polycarbonate particles have a bulk density of 0.40 to 0.70 g / cm ³ as measured by the ASTM D1895 method. Method for producing granular polycarbonate.
According to claim 1,
The average particle diameter of the granular polycarbonate particles is 0.3 to 10 mm, a method for producing granular polycarbonate.
According to claim 1,
Method for producing granular polycarbonate, wherein 80 to 90% by weight of the organic solvent contained in the polycarbonate polymerization solution is removed by the heating process compared to the first 100% by weight.

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