KR102349079B1 - Method for purifying polycarbonate resin - Google Patents

Abstract

The present invention relates to a method for purifying polycarbonate. More specifically, according to the present invention, the volatile organic compound is effectively removed from the polycarbonate that has undergone the granulation process during the polycarbonate manufacturing process using a steam stripping device having a plurality of perforated plates or bubble caps in the form of a sieve to reduce the content thereof. By minimizing it, there is provided a method for purifying polycarbonate that can reduce energy consumption compared to the prior art, exhibit high-temperature stability, and provide a polycarbonate resin with excellent product quality.

Description

Purification method of polycarbonate resin {METHOD FOR PURIFYING POLYCARBONATE RESIN}

The present invention effectively removes a volatile solvent from a granular polycarbonate solution containing a volatile solvent that has undergone a conventional granulation process of polycarbonate by using a plurality of specific perforated plates in the form of a sieve or a steam stripping device equipped with a bubble cap or bubble cap. It relates to a method for purifying (degassing, or removing a volatile solvent) of a polycarbonate resin capable of improving product physical properties by removing it.

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

Such polycarbonate is usually prepared through a method of reacting a divalent hydroxy compound with phosgene or an exchange method of reacting a divalent hydroxy compound with a diester carbonate.

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

Thereafter, the polycarbonate may be subjected to a granulation process, in which the granulated polycarbonate contains a large amount of solvent (eg, methylene chloride) and an anti-solvent used for granulation. It is present in a swollen state in the granular polycarbonate.

Therefore, in order to provide a final product, the solvents need to be removed. In the past, in order to remove the solvents, a solvent has been removed from the swollen polymer using a vacuum dryer. However, the conventional method requires a multi-stage facility, and in particular, a high temperature (100 to 130° C.) and a high vacuum (1 to 100 Torr) are required, thereby consuming a lot of energy.

It is an object of the present invention to easily remove solvents, which are volatile organic compounds, from swollen granule polycarbonate (granule PC), and to purify (degas) polycarbonate resin including a continuous process that is more efficient than conventional methods and lowers energy consumption , or volatile solvent removal) method.

The present invention comprises the steps of: a) providing a granular polycarbonate solution containing a volatile organic compound produced through a granulation process after polymerization of polycarbonate; and

b) removing the volatile organic compound by introducing the granular polycarbonate solution containing the volatile organic compound into a steam stripping device having a plurality of perforated plates or bubble caps therein;

It provides a method of purifying (degassing, or removing a volatile solvent) of a polycarbonate resin, comprising a.

The steam stripping device includes a first inner wall and a second inner wall facing each other, having a plurality of perforated plates or bubble caps therein, and having a downcomer inside a column, the stripping column, the stripping column A solution supply port provided on one side of the stripping column, a steam inlet provided on one side of the lower end of the stripping column, a discharge port provided at the bottom of the stripping column and a resultant solution (product) through a plurality of perforated plates or bubble caps, and the A solvent outlet including a volatile organic compound is provided in the upper portion of the stripping column, and the plurality of perforated plates or bubble caps may be alternately and repeatedly arranged so that the fluid flows in multiple stages in the stripping column. The downcomer includes a configuration well known in the art, and may refer to a flow path pipe part such as a pipe for sending a fluid or material downward.

In addition, in the stripping column, the number of stages is not particularly limited, but the number of degassing stages may be 3 to 10 stages.

In addition, the plurality of perforated plates or bubble caps have one end fixed to the first inner wall of the stripping column and one end of the plurality of first perforated plates or bubble caps positioned apart from the second inner wall, one end of the stripping column and a plurality of second perforated plates or bubble caps fixed to the second inner wall and having an opposite end positioned apart from the first inner wall, wherein the first perforated plate or bubble cap and the second perforated plate or bubble cap are alternately arranged one by one It may include a plurality of perforated trays.

The present invention specifically relates to a polycarbonate containing a swollen volatile organic compound that has been granulated using a steam stripping column equipped with a plurality of perforated plates or bubble caps in the form of a sieve, effectively, There is an effect of providing a continuous purification method of polycarbonate resin that can reduce energy consumption by removing volatile organic compounds to improve product quality and, in particular, not to operate under high temperature and high vacuum conditions.

1 schematically shows a steam stripping apparatus used in a purification process of a polycarbonate resin according to an embodiment of the present invention.

Hereinafter, the present invention will be described in more detail. The terms or words used in the present specification and claims should not be construed as being limited to their ordinary or dictionary meanings, and the inventor may properly define the concept of the term in order to best describe his invention. Based on the principle that there is, it should be interpreted as meaning and concept consistent with the technical idea of the present invention.

Also, the meaning of "comprising" as used herein in the context of the present invention embodies a particular characteristic, region, integer, step, operation, element and/or component, and other characteristic, region, integer, step, operation, element and/or It does not exclude the presence or addition of ingredients.

Hereinafter, a method for purifying a polycarbonate resin according to a preferred embodiment of the present invention will be described.

According to an embodiment of the present invention, a method comprising: a) providing a volatile organic compound-containing granular polycarbonate solution produced through a granulation process after polymerization of polycarbonate; And b) adding the volatile organic compound-containing granular polycarbonate solution to a steam stripping device having a plurality of perforated plates or bubble caps therein, and removing the volatile organic compound; Purification of polycarbonate resin comprising; A method is provided.

First, in the present invention, the purification method of the polycarbonate resin is intended to include a method of degassing a solvent or a method of removing a volatile solvent.

In the present invention, by using a sieve-type steam stripping device to remove the solvents contained in the granular polycarbonate, it is to provide a method for minimizing the content of the solvent in the final product.

As described above, in general, in order to remove the solvent of the swollen polycarbonate polymer after the granulation process, it was carried out at a high temperature and in a high vacuum. However, when granular polycarbonate is exposed to high temperatures for a long time, color deterioration and quality deterioration may occur.

On the other hand, the technology to be proposed in the present invention by using a specific steam stripping device, since it operates for a short time, it is possible to minimize damage to the product as in the prior art even when exposed to high temperatures.

In addition, in the polycarbonate swollen after the granulation process, about 3 to 10 wt% of the organic solvent is present. After the purification method according to the method of the present invention, the organic solvent becomes 10 ppm or less in the final polycarbonate, the solvent content can be minimized.

Specifically, each step will be described.

Step a) is a step of providing a granular polycarbonate solution containing a volatile organic compound by performing a granulation process in a conventional manner after a series of purification processes are performed on the polycarbonate resin that has completed the polymerization process.

In this case, the volatile organic compound is a solvent containing methylene chloride, 1,2-dichloroethane, or chlorobenzene; and an anti-solvent selected from the group consisting of hexane, heptane, methanol, ethanol, propanol, isopropanol, acetone, and toluene; may include.

In addition, the volatile organic compound-containing granular polycarbonate solution of a) may contain 3 to 10% by weight of the volatile organic compound based on the weight of the total solution. The content of the volatile organic compound is the content before reducing the content of the volatile organic compound by the method of FIG. 1 of the present invention. And, through the purification method of the present invention, the content of the volatile organic compound (ie, organic solvent) in the granular polycarbonate solution containing the volatile organic compound is greatly reduced, for example, the organic solvent in the polycarbonate resin is reduced to 10ppm or less. . Preferably, after the purification method of the present invention, the content of the residual volatile organic compound in the polycarbonate resin is 0.0001 to 15% by weight or 0.001 to 0.7% by weight or less, or 0.001 to 0.64% by weight compared to the initial 100% by weight It may be .

The volatile organic compound-containing granular polycarbonate solution of a) may further include water.

The volatile organic compound-containing granular polycarbonate solution includes granular polycarbonate in the form of beads or amorphous.

Then, in the present invention, b) a step of removing the volatile organic compound by introducing the volatile organic compound-containing granular polycarbonate solution into a steam stripping device having a plurality of perforated plates or bubble caps therein.

That is, in the present invention, a steam stripping device having a plurality of porous plates or bubble caps having a specific sieve shape is used, wherein the steam stripping device includes a plurality of porous plates or bubble caps arranged in multiple stages alternately therein. stripping column.

When the volatile organic compound-containing granular polycarbonate solution is put into the steam stripping device, it is driven to vapor-liquid equilibrium by the steam injected from the bottom, so that the granular polycarbonate solution moves along a plurality of perforated plates or bubble caps. The volatile materials contained in the granular polycarbonate are removed while moving downward. In addition, the volatiles are discharged in gaseous form to the top of the stripping device after being separated from the granular polycarbonate.

In particular, in the present invention, as the volatile substances adsorbed in the granular polycarbonate descend along a plurality of perforated plates or bubble caps provided in the stripping column, it can be more effectively desorbed from the granular polycarbonate. In this way, when reaching the bottom of the stripping column, the content of volatiles in the polycarbonate can be minimized.

Preferably, after step b), the content of the volatile organic compound may be 10 ppm or less based on the weight of the total solution.

Hereinafter, the configuration of the present invention will be described in more detail with reference to the drawings.

1 schematically shows a steam stripping apparatus used in a purification process of a polycarbonate resin according to an embodiment of the present invention.

As shown in FIG. 1, the steam stripping apparatus used in the present invention includes a first inner wall and a second inner wall facing each other, and has a plurality of perforated plates or bubble caps (a plurality of trays) therein, and a column ( Column) stripping column 100 with a downcomer inside, a solution supply port 10 provided on one side of the stripping column, a steam inlet 20 provided on one side of the lower end of the stripping column, the It is provided at the bottom of the stripping column and includes an outlet 30 for a solution (product) as a result of passing through a plurality of perforated plates or bubble caps, and a solvent outlet 40 including a volatile organic compound provided at the top of the stripping column, The plurality of perforated plates or bubble caps may include a structure in which the fluid flows in multiple stages in the stripping column and is alternately and repeatedly arranged.

The solution supply port may be located on the side of the stripping column, the position is not limited, and may be appropriately adjusted as necessary. In the case of Figure 1, the solution supply port 10 shows an example disposed on the upper side of the stripping column.

A volatile organic compound-containing granular polycarbonate solution generated through a granulation process after polymerization of polycarbonate may be supplied to the solution supply port.

The solution discharged to the solution outlet 30 may be connected back to a reboiler for supplying steam.

In addition, the plurality of perforated plates or bubble caps have one end fixed to the first inner wall of the stripping column and one end of the plurality of first perforated plates or bubble caps positioned apart from the second inner wall, one end of the stripping column and a plurality of second perforated plates or bubble caps fixed to the second inner wall and having an opposite end positioned apart from the first inner wall, wherein the first perforated plate or bubble cap and the second perforated plate or bubble cap are alternately arranged one by one It may mean including a plurality of perforated trays.

Also, the apparatus of the present invention may be a conventional sieve tray column. Accordingly, the sheave tray may mean a plurality of perforated plates.

The plurality of perforated plates 12 may be in the form of a sieve including a plate in which a hole 14 is drilled in a size of 1 mm to 10 mm or 2 mm to 10 mm at a predetermined interval. In addition, in the plurality of perforated plates, a through hole in which a hole called a perforate (sieve) is drilled in one plate includes form. The size of the hole means the diameter, and when the diameter of the hole satisfies the above range, the flow of the solution can be smoother and volatile substances can be more effectively desorbed from the granular polycarbonate,

1 shows an example of a part of a side view of a sieve tray with holes of the present invention. At this time, although the configuration of the plurality of perforated plates is simply illustrated as a circle region, the configuration is not limited, and a plurality of holes 14 are included on the plate, including a sieve tray configuration according to a method well known in the art. It may include what has been manufactured.

In addition, at least one of the plurality of perforated plates or bubble caps may be provided in the stripping column, preferably 3 to 15, and most preferably 5 to 10.

In addition, in the present invention, since the steam stripping device is operated within a shorter time than before, damage to the product can be minimized. Preferably, in the present invention, the steam stripping device is 80 ℃ to 100 ℃ temperature, or 85 to 95 ℃ temperature, -0.05kgf to -0.001kgf, or -0.03 to -0.01kgf under pressure, 20 minutes to 60 minutes Alternatively, it may be operated for 30 to 60 minutes.

If the operating time of the stripping device is less than 20 minutes, there is a problem that the removal of volatile solvents may be less, and if it exceeds 60 minutes, there is a problem of deterioration of mechanical properties.

In addition, when the temperature or pressure of the stripping device is within the above range, it is possible to effectively remove the volatile organic compound from the polycarbonate while reducing energy consumption.

In addition, the stripping column of the present invention may include reflux, but the column does not necessarily include a reflux configuration. Although not shown in the drawings, the stripping column may be connected to a pump for transferring the feed solution or the product solution, and even if the stripping column does not include reflux, the feed solution may be transferred through the pump.

In the present invention, a granular polycarbonate solution containing a volatile organic compound generated through a granulation process after polymerization of polycarbonate is supplied to a stripping column as shown in FIG. 1, and a volatile organic compound in the solution is passed through a plurality of perforated plates or bubble caps. The solvent containing the is removed, and the remaining solution may be discharged through the outlet 30 of FIG. 1 . In addition, when all the volatile organic compounds are removed, the solution obtained through the outlet 30 may be collected, and an additional purification process may be further performed.

In the same principle as in FIG. 1, a granular polycarbonate solution containing a volatile organic compound generated through a granulation process after polymerization of polycarbonate is supplied to a stripping column, and a volatile organic compound is contained in the solution through a plurality of perforated plates or bubble caps. One solvent is removed, and the remaining solution may be discharged through the outlet 30 of FIG. 1 .

On the other hand, the polymerized polycarbonate resin before the granulation process may be a homopolymer or copolymer having a carbonate repeating unit represented by the following formula (1).

[Formula 1]

In Formula 1, R ¹ may be derived from a dihydroxy compound such as an aromatic dihydroxy compound represented by Formula 2 or bisphenol represented by Formula 3 below.

[Formula 2]

(In Formula 2, R ^h is each independently a halogen atom, a halogen atom-substituted or unsubstituted C _1-10 alkyl, and a halogen atom-substituted or unsubstituted C _6-10 aryl, n is 0 to 4 is an integer of)

[Formula 3]

(In Formula 3, R ^a and R ^b are each independently halogen, C _1-12 alkoxy and C _1-12 alkyl, p and q are each independently an integer of 0 to 4, p or q is If less than 4, the valence of each carbon of the ring may be filled with hydrogen,

X ^a is a linking group connecting two hydroxy-substituted aromatic groups, -O-, -S-, -S(O)-, -S(O) ₂ -, -C(O)- or C _1-18 is an organic group of, and the C _1-18 organic group is a substituted or unsubstituted C _2-18 cycloalkylidene, -C(R ^c )(R ^d )-, C _1-25 alkylidene (where R ^c and R ^d are independently of each other hydrogen, C _1-12 alkyl, C _1-12 cycloalkyl, C _7-12 arylalkyl, C _1-12 heteroalkyl or C _7-12 heteroarylalkyl ) or -C(=R ^e ) (where R ^e is a divalent hydrocarbon of _{C 1-12 ))}

Specific examples of the dihydroxy compound include 4,4'-dihydroxybiphenyl, 1,6-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, bis(4-hydroxyphenyl)methane, bis (4-hydroxyphenyl)diphenylmethane, bis(4-hydroxyphenyl)-1-naphthylmethane, 1,2-bis(4-hydroxyphenyl)ethane, 1,1-bis(4-hydroxyl Phenyl)-1-phenylethane, 2-(4-hydroxyphenyl)-2-(3-hydroxyphenyl)propane, bis(4-hydroxyphenyl)phenylmethane, 2,2-bis(4-hydroxyl -3-Bromophenyl)propane, 1,1-bis(hydroxyphenyl)cyclopentane, 1,1-bis(4-hydroxyphenyl)cyclohexane, 1,1-bis(4-hydroxyphenyl)isobu Ten, 1,1-bis(4-hydroxyphenyl)cyclododecane, trans-2,3-bis(4-hydroxyphenyl)-2-butene, 2,2-bis(4-hydroxyphenyl)a Danantane, α,α'-bis(4-hydroxyphenyl)toluene, bis(4-hydroxyphenyl)acetonitrile, 2,2-bis(3-methyl-4-hydroxyphenyl)propane, 2,2 -bis(3-ethyl-4-hydroxyphenyl)propane, 2,2-bis(3-n-propyl-4-hydroxyphenyl)propane, 2,2-bis(3-isopropyl-4-hydroxy Phenyl)propane, 2,2-bis(3-sec-butyl-4-hydroxyphenyl)propane, 2,2-bis(3-t-butyl-4-hydroxyphenyl)propane, 2,2-bis( 3-cyclohexyl-4-hydroxyphenyl)propane, 2,2-bis(3-allyl-4-hydroxyphenyl)propane, 2,2-bis(3-methoxy-4-hydroxyphenyl)propane, 2,2-bis(4-hydroxyphenyl)hexafluoropropane, 1,1-dichloro-2,2-bis(4-hydroxyphenyl)ethylene, 1,1-dibromo-2,2-bis (4-hydroxyphenyl) ethylene, 1,1-dichloro-2,2-bis (5-phenoxy-4-hydroxyphenyl) ethylene, 4,4'-dihydroxybenzophenone, 3,3-bis (4-hydroxyphenyl)-2-butanone, 1,6-bis(4-hydroxyphenyl)-1,6-hexadione, ethylene glycol bis(4-hydroxyphenyl)ether, bis(4-hydroxyl) Roxyphenyl)ether, bis(4-hydroxyphenyl)sulfide, bis(4-hydroxyphenyl)sulfoxide, bis(4-hydroxyphenyl)sulfone, 9,9-bis(4-hydroxyphenyl)fluoro Lin, 2,7-dihydroxypyrene, 6,6'-dihydroxy-3,3,3',3'-tetramethylspiro(bis)indane (spirobiindane bisphenol), 3,3-bis(4-hydroxyphenyl)phthalimide, 2 ,6-dihydroxydibenzo-p-dioxine, 2,6-dihydroxythianthrene, 2,7-dihydroxyphenoxatin, 2,7-dihydroxy-9,10-dimethylphenazine, bisphenol compounds such as 3,6-dihydroxydibenzofuran, 3,6-dihydroxydibenzothiophene, and 2,7-dihydroxycarbazole; 5-methyl resorcinol, 5-ethyl resorcinol, 5-propyl resorcinol, 5-butyl resorcinol, 5-t-butyl resorcinol, 5-phenyl resorcinol, 5-cumyl resorcinol , 2,4,5,6-tetrafluoro resorcinol, 2,4,5,6-tetrabromo resorcinol, etc. substituted resorcinol compounds; catechol; hydroquinone; and 2-methyl hydroquinone, 2-ethyl hydroquinone, 2-propyl hydroquinone, 2-butyl hydroquinone, 2-t-butyl hydroquinone, 2-phenyl hydroquinone, 2-cumyl hydroquinone, 2,3,5 ,6-tetramethyl hydroquinone, 2,3,5,6-tetra-t-butyl hydroquinone, 2,3,5,6-tetrafluoro hydroquinone, 2,3,5,6-tetrabromo hydro Substituted hydroquinones, such as a quinone, etc. are mentioned.

The organic solvent may be methylene chloride (CH ₂ Cl ₂ ), 1,2-dichloroethane (C ₂ H ₄ Cl ₂ ), chlorobenzene (C ₆ H ₅ Cl), or toluene (C ₇ H ₅ ), etc., Specifically, it may be methylene chloride.

The catalyst component may be triethylamine, tributylamine, N,N-diethyl-cyclohexylamine, N,N-dimethylaniline, or the like, specifically triethylamine (TEA).

The salt component may be sodium chloride, sodium carbonate, or the like.

And, by-products that may be generated in the process of manufacturing the polycarbonate may be removed by purification according to a method well known in the art. For example, since the salt component of the by-product has high solubility in water, it can be removed through an extraction method using water.

In addition, the polycarbonate purification process may include a catalyst removal process, and the catalyst removal may be performed simultaneously with or before the by-product removal process.

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

Example 1 and 2.

After the conventional PC manufacturing process, the methylene chloride (MC)-containing granular polycarbonate solution produced in the granulation process was removed using the steam stripping apparatus of FIG. 1, MC was removed from the solution.

Example 1: 80 wt% solution of water (100 g of water, 20 g of PC (MFR 10g/10min), 5 g of MC), temperature of stripping device: 85° C., pressure: -0.02 kgf, running time: 30 minutes

Example 2: Water 46 wt% solution (water 57.6 g, PC 57.6 g (MFR 10g/10min), MC 9.8 g), temperature of stripping device: 95° C., pressure: -0.01 kgf, running time: 20 minutes

Then, in order to check the damage of the polycarbonate due to heat, for the polycarbonate after going through the apparatus of FIG. 1, in the following way Physical properties (YI, haze and Izod impact strength) and residual solvent content were measured, and the results are shown in Tables 1 and 2.

1) Izod impact strength (Notched IZOD, kgf·cm/cm): Means room temperature impact strength, and was measured at 25° C. according to ASTM D256 method.

2) YI (Yellow index): After injection molding a specimen (width/length/thickness = 60 mm/ 40 mm/ 3 mm) at 300°C using polycarbonate, according to ASTM D1925, this is Color-Eye 7000A ( YI (Yellow Index) was measured under the following conditions using X-rite Co., Ltd.).

- Measurement temperature: room temperature (23℃)

- Aperture size: Large area of view

- Measurement method: transmittance measurement in the spectral range (360 nm to 750 nm)

3) Haze: Measured according to ASTM 1003.

4) Residual MC amount: With respect to the granular polycarbonate solution containing volatile organic compounds, the organic solvent content in the polycarbonate resin before and after passing through the apparatus of FIG. 1 was measured and analyzed by GPC.

Example 1: 80 wt% solution of water 9.4 wt% 7wt% 10wt% number of degassing stages residual
MC Amount (%) IZOD
(25℃) YI Haze residual
MC Amount (%) IZOD
(25℃) YI Haze residual
MC Amount (%) IZOD
(25℃) YI Haze 0 100 950 1.5 0.8 100 890 1.6 0.9 100 940 2.0 1.1 3 13 15 10 5 5 4.7 4.8 8 0.1 0.013 0.09 10 0.0087 860 2.1 1.2 0.009 850 2.3 1.3 0.64 790 2.4 1.4

Example 2: 46wt% water solution 9.1 wt% 10wt% 8.4 wt% number of degassing stages residual
MC Amount (%) IZOD
(25℃) YI Haze residual
MC Amount (%) IZOD
(25℃) YI Haze residual
MC Amount (%) IZOD
(25℃) YI Haze 0 100 900 1.7 1.1 100 850 1.7 1.1 100 830 2.0 1.2 3 10 12 7 5 3.2 3.9 2.4 8 0.1 0.017 0.08 10 0.0095 780 2.3 1.4 0.0098 750 2.3 1.3 0.56 750 2.4 1.4

From the results of Tables 1 and 2, in the case of the present invention, it was confirmed that there was almost no difference in the physical properties of the polycarbonate before and after using the steam stripping device.

100: stripping column having a plurality of perforated plates or bubble caps therein
10: solution supply port
12: a plurality of perforated plates or bubble caps (multiple trays)
14: hole
20: steam inlet
30: outlet
40: solvent outlet

Claims (9)

a) providing a granular polycarbonate solution containing a volatile organic compound produced through a granulation process after polymerization of polycarbonate; and
b) adding the volatile organic compound-containing granular polycarbonate solution to a steam stripping device having a plurality of perforated plates or bubble caps therein, and removing the volatile organic compounds;
The steam stripping device is operated at a temperature of 85 ° C. to 95 ° C. and a pressure of -0.05 kgf to -0.001 kgf, for 20 minutes to 60 minutes.
According to claim 1, wherein the steam stripping device,
A stripping column including a first inner wall and a second inner wall facing each other, having a plurality of perforated plates or bubble caps therein, and having a downcomer inside the column;
A solution supply port provided on one side of the stripping column,
A steam inlet provided on one side of the lower end of the stripping column,
An outlet provided at the bottom of the stripping column and passing through a plurality of perforated plates or bubble caps, and
Including a volatile organic compound outlet provided at the top of the stripping column,
The plurality of perforated plates or bubble caps are alternately and repeatedly arranged so that the fluid flows in multiple stages in the stripping column.
3. The method of claim 2,
The plurality of perforated plates or bubble caps,
A plurality of first perforated plates or bubble caps having one end fixed to the first inner wall of the stripping column and one end positioned apart from the second inner wall;
and a plurality of second perforated plates or bubble caps having one end fixed to the second inner wall of the stripping column and one end positioned apart from the first inner wall,
The first perforated plate or bubble cap and the second perforated plate or bubble cap are alternately arranged one by one,
A method for purifying polycarbonate resin, comprising a plurality of porous trays.
According to claim 1,
The plurality of perforated plates or bubble caps are in the form of a sieve including a plate having holes of 1 mm to 10 mm at a predetermined interval, the method for purifying polycarbonate resin.
delete The method of claim 1 , wherein the volatile organic compound-containing granular polycarbonate solution comprises granular polycarbonate of a bead form or amorphous form.
The method of claim 1, wherein the granular polycarbonate solution containing a volatile organic compound of a) further comprises water.
According to claim 1, wherein the volatile organic compound,
a solvent comprising methylene chloride, 1,2-dichloroethane or chlorobenzene; and
An anti-solvent selected from the group consisting of hexane, heptane, methanol, ethanol, propanol, isopropanol, acetone, and toluene;
A method for purifying polycarbonate resin.
The method according to claim 1, wherein after step b), the content of the volatile organic compound is 10 ppm or less based on the weight of the total solution.

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