JPH0952949A - Washing of organic solvent solution of polycarbonate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accomplish a washing at low cost of the subject solution in high washing efficiency in a short separation time by mixing and agitating the subject solution containing impurities and an aqueous washing liquid to form a specific water-in-oil disperse phase and by incorporating the disperse phase with an additional washing liquid followed by agitation to effect phase conversion into an oil-in-water disperse phase, which is then separated. SOLUTION: (A) An impurity-contg. organic solvent solution of a polycarbonate is mixed with (B) an aqueous washing liquid so as to be 1-40vol.% in the aqueous phase ratio, and the mixture is agitated by e.g. a line mixer 3 so as to bring the diameter of dispersed droplets to <=100μm to form a water-in-oil disperse phase. Next, the resultant mixture is incorporated with a necessary amount of the liquid B so as to be 15-90vol.% in the aqueous phase ratio and the system is then agitated by e.g. an orifice mixer or static mixer 6 so as to minimize the amount of the water necessary for phase conversion and existing in the solution A after phase separation to effect phase conversion into an oil-in-water disperse phase, which is then separated into A-phase 9 and B- phase in e.g. a static separation tank 7.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for cleaning a polycarbonate organic solvent solution. For more information,
By efficiently washing a polycarbonate organic solvent solution containing impurities such as a crude polycarbonate organic solvent solution produced by an interfacial polymerization method with an aqueous cleaning solution, a purified polycarbonate organic solvent solution can be obtained, and The present invention relates to a method for cleaning a polycarbonate organic solvent solution that can achieve this with inexpensive equipment.

[0002]

2. Description of the Related Art As a method for producing polycarbonate, a polymerization method by an interfacial method using an organic solvent such as methylene chloride is usually carried out. In the crude polycarbonate organic solvent solution polymerized by this method, unreacted monomers, impurities generated during the polymerization reaction or impurities generated by other causes, particularly phenols, strong alkalis, ammonium salts used as catalysts , By-products such as inorganic salts and their ions are included.

When these impurities remain in the polymer, they cause problems such as coloring, deterioration of thermal stability, deterioration of steam resistance and the like. Therefore, these impurities are generally removed by washing with water using a multistage extraction method, an orifice tower, a stirring tank, etc. However, if the concentration of the polycarbonate in the organic solvent solution is high, the solution becomes highly viscous. Therefore, it cannot be sufficiently removed by a simple washing operation.

Therefore, as a cleaning technique under such high concentration and high viscosity conditions, for example, Japanese Patent Publication No. 59-
As disclosed in Japanese Patent No. 38967, a method in which after washing with a water-in-oil type dispersed phase in two stages of a stirring tank, the phase is converted into an oil-in-water type dispersed phase and separated in a stationary separation tank, JP-A-63-1050.
28, JP-A-1-96212, etc., a method of forming a water-in-oil type dispersed phase after stirring with a stirring power of a certain level or more, and then separating using a centrifugal separator, etc. Has been adopted.

[0005]

However, in the cleaning method disclosed in Japanese Examined Patent Publication No. 59-38967, it is the same when forming the water-in-oil type dispersed phase in the former stage and in forming the oil-in-water type dispersed phase in the latter stage. Since stirring is carried out, the detergency and the separability between the polycarbonate organic solvent solution and the aqueous cleaning solution are not sufficiently satisfactory.

A centrifuge is effective for separating the polycarbonate organic solvent solution and the aqueous cleaning solution, but the equipment cost is high. On the other hand, the mere static separation method that is generally used has a disadvantage that the time required for separation is long. Further, the water content remaining in the polycarbonate organic solvent solution contains many impurities that adversely affect the physical properties of the polymer, and it is necessary to further reduce the water content during separation.

According to the present invention, in a step of forming a water-in-oil type dispersed phase and an oil-in-water type dispersed phase by mixing a crude polycarbonate organic solvent solution and an aqueous washing solution, an appropriate stirring power is applied to the mixture. The purpose is to efficiently wash by providing, enhance the separability of the organic solvent solution phase and the aqueous washing liquid phase, reduce the residual water content, and shorten the time required for the separation. Moreover, it aims at achieving this with an inexpensive facility.

[0008]

In order to achieve the above-mentioned object, the invention according to claim 1 in the present invention is a method for cleaning a polycarbonate organic solvent solution containing impurities by using an aqueous cleaning solution, (1) The polycarbonate organic solvent solution and the aqueous cleaning solution are mixed so as to have an aqueous phase ratio of 1 to 40% by volume, and the dispersed droplet diameter formed is 1
The first step of stirring this with a stirring power of not more than 00 μm to form a water-in-oil type dispersed phase, and (2) then adding a necessary amount of the mixture so that the water phase ratio becomes 15 to 90% by volume. An aqueous washing liquid was further added, and the mixture was stirred with a stirring power in the vicinity that was sufficient to invert the phase and minimized the amount of water in the polycarbonate organic solvent solution after phase separation, and then transferred to the oil-in-water dispersed phase. The second step of causing the organic solvent solution and the aqueous cleaning solution to separate into a polycarbonate organic solvent solution phase and an aqueous cleaning solution phase (3). It enhances the separability.

Further, in the invention described in claim 2, when the concentration of the polycarbonate in the polycarbonate organic solvent solution is in the range of 6 to 30% by weight, the stirring in the first step exceeds 0.1 kW · hr / m ³ . The stirring power is 0.01 to 0.10 kW · hr / m ^{3 for} the stirring in the second step.
It is characterized in that the stirring power is within the range, and shows more specific cleaning conditions.

The invention described in claim 3 is the same as claim 1
Alternatively, in the invention described in 2, the separation step of separating the polycarbonate organic solvent solution phase and the aqueous cleaning liquid phase is a stationary separation method. Also,
The invention described in claim 4 is characterized in that, in the invention described in claims 1 to 3, the stirring means is a line mixer, an orifice mixer or a static mixer.

Further, in the invention described in claim 5, in the invention described in claims 1 to 4, as the aqueous cleaning liquid of the second step, all or part of the aqueous cleaning liquid separated in the separation step is recycled. It is characterized by being used.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The polycarbonate organic solvent solution targeted by the present invention is typically a polycarbonate organic solvent solution containing impurities taken out from an interfacial polymerization reaction system, but is not limited thereto. Not something
It may be a polycarbonate organic solvent solution that has been washed in advance or a separately prepared polycarbonate organic solvent solution.

The polymerization reaction by the interfacial method is a commonly used method, that is, a method in which phosgene is reacted with an aqueous solution of an alkali salt of a dihydroxy compound in the presence of an organic solvent. The organic solvent used in the polymerization reaction is a substantially water-insoluble organic solvent, specifically,
Methylene chloride, dichlorobenzene, chloroform, tetrachloroethane, trichloroethane, dichloroethane,
Examples include chlorinated hydrocarbons such as 1,2-dichloroethylene, and mixtures thereof with dioxane, tetrahydrofuran, acetophenone, acetone, toluene, xylene, n-heptane, cyclohexane, and the like. The organic solvent described above can be applied as the organic solvent in the solvent solution,
Among them, the chlorine-based hydrocarbon or a mixture containing 60% or more of the chlorine-based hydrocarbon is preferable, and methylene chloride is particularly preferable.

Examples of the dihydroxy compound include 2,2-bis (4-hydroxyphenyl) propane (also known as bisphenol A), bis (4-hydroxyphenyl) methane, 1,1-bis (4-hydroxyphenyl) ethane,
Bis (4-hydroxyphenyl) alkane such as 1,1-bis (4-hydroxyphenyl) butane, bis (4-hydroxyphenyl) sulfone, bis (4-hydroxyphenyl) sulfide, bis (4-hydroxyphenyl)
Examples thereof include sulfoxide and the like, or halogen-substituted dihydroxy compounds having a halogen atom such as chlorine and bromine in the hydroxybenzene nucleus.

Further, examples of the alkali for forming the alkali salt of these dihydroxy compounds include strong basic hydroxides such as caustic soda and caustic potash. The polycarbonate polymerized by reacting the above-mentioned dihydroxy compound with phosgene in an alkali salt solution is a usual polycarbonate obtained by the reaction of a bisphenol A-based dihydroxy compound with phosgene, and as a branching agent, phloroglucin, Trimellitic acid, 1,1,
1-tris (4-hydroxyphenyl) ethane, 1-
[Α-methyl-α- (4′-hydroxyphenyl) ethyl] -4- [α ′, α ″ -bis (4 ″ -hydroxyphenyl) ethyl] benzene or the like is used, and a polycarbonate having a branch, bromine or It may be a special polycarbonate such as a halogen-containing polycarbonate containing chlorine or the like, or a polycarbonate obtained by copolymerizing two or more dihydroxy compounds. In addition, if necessary, n-butylphenol, t-butylphenol, n
It may be a polycarbonate using benzylphenol, n-hexylphenol, cyclohexylphenol, phenylphenol, nonylphenol, naphthylphenol, cumylphenol, di-t-butylphenol, dicumylphenol or the like.

The molecular weight of the polycarbonate in the organic solvent solution of the polycarbonate containing impurities to be used in the present invention is not particularly limited as long as it can be handled as a solution, but usually, the viscosity average molecular weight (hereinafter referred to as Mv). Is 1,000 to 100,000, preferably Mv is 2.
It is 000 to 50,000. The concentration of the polycarbonate in the solution is usually 6 to 30% by weight, preferably 10 to 25% by weight. Concentration is 30% by weight
If it exceeds, the viscosity of the solution becomes high and gelation is likely to occur, which may make stable washing operation difficult. On the contrary, if the concentration is too low, the amount of the polycarbonate solution becomes large, and accordingly, a large amount of the aqueous cleaning liquid is also required, and the apparatus itself becomes large, which is economically disadvantageous.

As impurities in the polycarbonate organic solvent solution, dihydroxy compounds as unreacted monomers, sodium hydroxide as a strong alkali, a tertiary or quaternary ammonium salt used as a catalyst, and a by-product of polymerization It is conceivable that the substance is salt. Examples of the aqueous cleaning liquid include diluted alkaline water, pure water, diluted hydrochloric acid aqueous solution,
A dilute aqueous acid solution such as a dilute sulfuric acid aqueous solution may be mentioned. Generally, dilute alkaline water is mainly used for washing mainly for removing the alkali salt of the unreacted dihydroxy compound, and the purpose is to neutralize and remove the catalyst. A dilute aqueous acid solution is used for the washing, and purified water is used for the washing for the purpose of removing the residual acid and salt.

In the present invention, in the first step, a polycarbonate organic solvent solution containing impurities is mixed with an amount of an aqueous cleaning liquid capable of forming a water-in-oil type dispersed phase, and the dispersed droplet size becomes minute. By performing such stirring to form the water-in-oil type dispersed phase, the impurities in the polycarbonate organic solvent solution are efficiently eluted into the aqueous cleaning liquid that is the dispersed phase.

The amount of the aqueous cleaning solution to be mixed varies depending on the concentration of the polycarbonate in the polycarbonate organic solvent solution, the molecular weight, the capacity of the cleaning device used, etc., and cannot be specified uniformly, but the total volume of the polycarbonate organic solvent solution and the aqueous cleaning solution is Of 100% by volume, the aqueous cleaning liquid is mixed so that the volume ratio of the aqueous cleaning liquid, that is, the so-called aqueous phase ratio is 1 to 40% by volume, preferably 5 to 35% by volume. If the amount of this aqueous cleaning liquid is less than 1% by volume, the cleaning effect is reduced, while if it exceeds 40% by volume, an oil-in-water type dispersed phase is formed, and the cleaning effect is extremely reduced. The object of the invention cannot be achieved.

As a means for stirring, any equipment used for liquid-liquid agitation and mixing can be used, but an equipment which is short in residence time, compact, and capable of obtaining sufficient agitation power is preferable. A line mixer, an orifice mixer, or a static mixer is suitable as such a device. This aqueous cleaning solution is added in a small amount at the beginning,
It is also possible to form a water-in-oil type dispersed phase and then add the dispersed phase. Thereby, the water phase ratio at which the water-in-oil type dispersed phase can be maintained can be increased.

The polycarbonate organic solvent solution and the aqueous cleaning solution are mixed so that the water phase ratio is from 1 to 40% by volume, and the stirring power to form dispersed droplets having a particle size of 100 μm or less, preferably 70 μm or less. By stirring this to form a water-in-oil type dispersed phase, the cleaning effect is improved. To make the dispersed droplet diameter minute, 0.1 kW
-The stirring power may exceed hr / m ³ . When the stirring power is not more than the above, the liquid mixture may not be fine droplets, and the cleaning effect may be lowered.

The stirring power used in the line mixer is
Calculate using the following formula. Pv = ρ × n ³ × Np × d ⁵ / F / gc Pv: stirring power (kW · hr / m ³ ), ρ: liquid density (kg / m ³ ) n: rotation speed (rps), Np: power number (-) d: turbine diameter (m), F: liquid flow rate (m ³ / hr) gc: gravity conversion coefficient (kg · m / kgf / s 2) Moreover, in the orifice mixer or static mixer, calculates the following equation . Pv = f × ΔP (f = 1 / 36.7) Pv: stirring power (kW · hr / m ³ ), ΔP: differential pressure (kgf / cm ² ) f: conversion coefficient (kW · hr · cm ² / m) ³ / kgf) In the second step, the whole or a part of the mixture that forms the water-in-oil type dispersed phase obtained as described above is mixed with the necessary amount of the aqueous washing liquid in order to form the oil-in-water type dispersed phase in the second step. After adding
Stirring is performed with stirring power in the vicinity that is sufficient for phase inversion and minimizes the amount of water in the polycarbonate organic solvent solution after phase separation to invert the oil-in-water dispersed phase. Stirring with stirring power in the vicinity that minimizes the amount of water in the polycarbonate organic solvent solution after phase separation means that the maximum value of the stirring power is the value when the amount of water in the polycarbonate organic solvent solution after phase separation becomes the minimum. It means up to twice the stirring power.

As a stirring power in the vicinity of causing a phase inversion and minimizing the amount of water in the polycarbonate organic solvent solution after phase separation, 0.01 to 0.10 kW · hr /
m ³ , preferably 0.01 to 0.06 kW · hr / m
The stirring power in the range of ³ can be selected. Since the phase formed by the polymer solution and water generally has a hysteresis phenomenon, the phase may not be inverted only by setting the water phase ratio within a predetermined range, and a certain amount of stirring is required. If the stirring power is less than 0.01 kW · hr / m ³ , the added aqueous cleaning liquid will not be uniformly dispersed, and it will be difficult to invert the phase efficiently. On the other hand, 0.10k
If the stirring power exceeds W · hr / m ³ , the phase will be excessively stirred and the aqueous cleaning solution from which impurities have been extracted will be redispersed, and the cleaning effect will decrease, and the separation time thereafter. Also tends to be long.

The amount of the aqueous cleaning liquid added at the time of phase inversion varies depending on the amount of the aqueous cleaning liquid added to form the water-in-oil type dispersed phase, but usually the aqueous phase ratio is 1
It is good to add it until it becomes the range of 5-90 volume%, preferably 25-90 volume%. If the water phase ratio is less than 15% by volume, it is difficult to form and retain the oil-in-water type dispersed phase,
If it exceeds 90% by volume, a large amount of the aqueous cleaning liquid to be used is required, which is not efficient.

The aqueous cleaning liquid to be added may be an aqueous cleaning liquid purified in the same manner as in the first step, but in order to reduce the amount of use, one of the aqueous cleaning liquids after the intended cleaning is separated. Part or all may be recycled for use. As a means for stirring when carrying out this phase inversion, any equipment used for liquid-liquid stirring and mixing can be used, but a static mixer or an orifice mixer is preferable from the viewpoint of not requiring large stirring power. .

The mixture thus phase-inverted is then separated into a polycarbonate organic solvent solution phase and an aqueous cleaning liquid phase in a separation step. This separation can be separated using a generally known static separation tank, centrifuge, tower separator, etc., but by performing phase inversion with appropriate stirring power as described above, the separated state is The static separation method using a static separation tank is preferable from the viewpoint of significantly improved water content in the final separated purified polycarbonate organic solvent solution and the facility cost.

Next, an example of an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic view showing an example of an apparatus used for carrying out the present invention, 1 is a crude polycarbonate organic solvent solution introducing pipe, 2 is an aqueous cleaning liquid introducing pipe, 3 is a line mixer, 4 is an aqueous cleaning liquid supply pipe, 5 is a separation water recycling system, 6 is an orifice mixer or static mixer, 7 is a stationary separation tank, 8 is an aqueous cleaning liquid phase, 9 is an organic solvent solution phase, 10 is a transport pump, 11 is a drain pipe to a drainage system, 12 Indicates a supply pipe to the next step.

The crude polycarbonate organic solvent solution was introduced through the inlet pipe 1, the aqueous cleaning liquid was supplied through the supply pipe 2, and the line mixer 3 was used to perform stirring to make the particle size of the dispersed droplets minute, thereby forming a water-in-oil type dispersed phase. After being formed, a new aqueous cleaning liquid or separated water recycle is further supplied from the supply pipe 4 or the separated water recycle system 5, and is necessary for phase inversion with an orifice mixer or a static mixer, and a polycarbonate organic solvent after phase separation. Stirring is performed so as to minimize the amount of water in the solution, and the phase is inverted to the oil-in-water type dispersed phase. The liquid is separated by allowing it to stand in the standing separation tank 7.

The polycarbonate organic solvent solution according to the present invention can be washed in multiple stages. In that case, an apparatus of the same type as described above may be used. The organic solvent solution phase 9 is extracted from the stationary separation tank, supplied to the introduction pipe 1 of the next cleaning device by a transport pump, and cleaned in the same manner. Further, the present invention can be applied to any of washing of a polycarbonate organic solvent solution under alkaline conditions, washing under acidic conditions, and washing with pure water.

[0030]

EXAMPLES The present invention will be described below with reference to Examples and Comparative Examples.
explain in detail. The present invention is not limited to the examples below. [Example 1] Methylene chloride, bisphenol A and phosgene were used as raw materials, triethylamine was used as a catalyst, and p-t was used as a terminal stopper.
A crude polycarbonate organic solvent solution was obtained by carrying out a polymerization reaction of polycarbonate by a usual interfacial method using -butylphenol and separating the emulsion of the polycarbonate with a centrifuge. The organic solvent solution had a polycarbonate concentration of 25% by weight and Mv of 26,500. When methylene chloride was further added to this to dilute it so that the polycarbonate concentration became 13% by weight, 131% by weight pp of unreacted bisphenol A was found in this crude polycarbonate organic solvent solution.
m, triethylamine contained impurities such as 45 ppm by weight.

For the purpose of mainly removing unreacted bisphenol A in the diluted crude polycarbonate organic solvent solution, the polycarbonate solution was washed with an alkali at an aqueous phase ratio of 20% by volume, so that the polycarbonate solution was supplied at a supply rate of 200 liters / hr. , An aqueous cleaning solution consisting of a caustic soda solution adjusted to pH = 12.5 was supplied with a line mixer (pipeline homomixer manufactured by Tokushu Kika Kogyo, 2
SL type, internal volume 0.3 liter, diameter of first turbine blade 4
2.5 mm, the diameter of the second turbine blade is 48.0 mm, the rotation speed is 3,000 rpm, and the power number at the time of power calculation is supplied to the first turbine Np = 1.4 and the second turbine Np = 0.8). The stirring power was 0.79 kW · hr / m ³ . The phase state of this mixed solution was found to be a water-in-oil type dispersed phase when examined by sampling at the mixer outlet. The dispersed droplet diameter was 45 μm.

Further continuously, p was added to this mixed solution.
An aqueous cleaning solution consisting of a caustic soda solution adjusted to H = 12.5 was supplied at a supply rate of 83 liters / hr and passed through an orifice to obtain a differential pressure ΔP = 2.0k.
gf / cm ^{2 is applied} and the mixture is substantially stirred (stirring power of 0.
054 kW · hr / m ³ ), and the phase was inverted to an oil-in-water type dispersed phase.

This was supplied to a stationary separation tank and separated into an organic solvent solution phase and an aqueous cleaning liquid phase. When the time required until 90% of the total amount of the aqueous cleaning liquid newly supplied to the stationary separation tank was separated was measured, it was 8 minutes. After further standing, the bisphenol A in the organic solvent solution phase was measured 1 hour after being supplied to the standing separation tank.
pm, which was sufficiently reduced, and it was confirmed that the purpose of alkali cleaning was achieved. The measurement was performed by liquid chromatography (Spectra Physics SP8800 type, column: Tosoh ODS80TS, 25 cm × 0.46 m).
mφ). In addition, 1 after being supplied to the stationary separation tank
When the water content of the organic solvent solution phase after the time was measured,
It was 3,200 ppm by weight. It was also confirmed that the water was sufficiently separated. The measurement was performed with a Karl Fischer moisture meter (Mitsubishi Chemical's CA-06 type, vaporizer VA-06 type). The results are shown in Tables 1 and 2.

Example 2 A static mixer (Sulzer static mixer manufactured by Sumitomo Heavy Industries, Ltd., inner diameter 10 mmφ, number of elements 12) was used as a mixer for phase inversion, and stirring power was 0.041 kW · hr / m ^3. And as the aqueous cleaning liquid to be supplied at the time of phase inversion, except that the recycling of the aqueous cleaning liquid separated in the stationary separation tank is used,
It carried out similarly to Example 1. The results are shown in Table 1 and Table 2.
Shown in

[Example 3] A line mixer (manufactured by Tokushu Kika Kogyo Co., Ltd., 2SL type, internal volume 0.3 liter, diameter of first turbine blade 42.5 mm, diameter of second turbine blade) 48.0 mm, rotation speed 1,400 rpm, power number at the time of power calculation is 1st turbine Np = 1.4, 2nd turbine Np = 0.8), stirring power is 0.080
except that the kW · hr / m ³ was carried out in the same manner as in Example 1. The results are shown in Tables 1 and 2.

[Comparative Example 1] A line mixer was used as a mixer for phase inversion, and the stirring power was 0.79 kW · hr /
The same procedure as in Example 1 was carried out except that m ³ was used. As a result, the residual bisphenol A was 53 ppm by weight,
The time required for the separation was 22 minutes, the desired cleaning effect was lowered, and the separability of the aqueous cleaning liquid was deteriorated. In addition, the residual water content was 9,800 ppm by weight, and it was found that the residual water content was large. The results are shown in Tables 1 and 2.

[Comparative Example 2] An orifice was used as a mixer during phase inversion, and stirring power was 0.49 kW · hr / m ^3.
Example 1 was repeated except that The results are shown in Tables 1 and 2.

[Comparative Example 3] A line mixer was used as a mixer for phase inversion, and the stirring power was 0.143 kW · hr.
The same procedure as in Example 1 was carried out except that / m ³ was used. The results are shown in Tables 1 and 2.

[Comparative Example 4] An orifice was used as a mixer for phase inversion, and the stirring power was 0.0054 kW · hr /
The same procedure as in Example 1 was carried out except that m ³ was used. The stirring power was low, the aqueous washing liquid added at the time of phase inversion was not sufficiently mixed, and the water-in-oil type dispersed phase and the oil-in-water type dispersed phase coexisted, and sufficient separation could not be achieved. The result is
It shows in Table 1 and Table 2.

Example 4 Triethylamine in the crude polycarbonate organic solvent solution which had been subjected to the alkali washing in Example 1 was measured and found to be 32 ppm by weight. Therefore, it was decided to further carry out acid washing. In this case, the aqueous cleaning liquid used was adjusted to pH = 2.0 with hydrochloric acid, and was washed under the same conditions as in Example 1 shown in Table 1. As a result, the time required for the separation was 3 minutes, triethylamine in the organic solvent solution phase was reduced to 0.1 ppm by weight, and the water content was reduced to 2,100 ppm by weight. The measurement of triethylamine was performed by gas chromatography (Shimadzu Corporation GC-14A type, column: PEG-2000 type). The results are shown in Tables 1 and 2.

[Embodiment 5] A static mixer (Sulzer static mixer manufactured by Sumitomo Heavy Industries, Ltd., inner diameter 10 mmφ, element number 24) was used as a mixer for phase inversion, and stirring power was 0.082 kW · hr / m ^3. Example 4 was repeated except that The results are shown in Table 1.
And Table 2.

[Example 6] As the aqueous cleaning liquid supplied at the time of phase inversion, recycling of the aqueous cleaning liquid separated in the stationary separation tank was used, the supply rate was 36 liters / hr, and the aqueous phase ratio was 30 volumes. The same procedure as in Example 4 was carried out except that the percentage was changed to%. The results are shown in Tables 1 and 2.

[Example 7] The number of revolutions of the line mixer at the time of washing was 4,000 rpm, the supply rate of the aqueous washing liquid adjusted to pH = 2.0 with hydrochloric acid was 35 liters / hr, and the aqueous phase ratio was 15% by volume. Further, the same procedure as in Example 4 was performed, except that the supply rate of the aqueous cleaning liquid at the time of phase inversion was 98 liter / hr. The results are shown in Tables 1 and 2.

[Embodiment 8] A line mixer was used as a mixer for phase inversion, and the stirring power was 0.080 kW · hr.
The same procedure as in Example 7 was carried out except that / m ³ was used. The results are shown in Tables 1 and 2.

[Comparative Example 5] An orifice was used as a mixer for phase inversion, and stirring power was 0.49 kW · hr / m ^3.
Acid cleaning was performed in the same manner as in Example 4 except that As a result, it was found that if the stirring power at the phase inversion was large, the cleaning property and the separability were deteriorated. The results are shown in Tables 1 and 2.

[Comparative Example 6] As the aqueous cleaning liquid supplied at the time of phase inversion, recycling of the aqueous cleaning liquid separated in the stationary separation tank was used, the supply rate was 36 liters / hr, and the aqueous phase ratio was 30% by volume. The same procedure as in Comparative Example 5 was carried out except that the above was carried out. The results are shown in Tables 1 and 2.

[Comparative Example 7] A line mixer was used as a mixer for phase inversion, and the stirring power was 0.143 kW · hr.
The same procedure as in Example 4 was carried out except that / m ³ was used. The results are shown in Tables 1 and 2.

[Comparative Example 8] An orifice was used as a mixer for phase inversion, and the stirring power was 0.0054 kW · hr /
except that the m ³ was performed in the same manner as in Example 4. The stirring power was low, the aqueous washing liquid added at the time of phase inversion was not sufficiently mixed, and the water-in-oil type dispersed phase and the oil-in-water type dispersed phase coexisted, and sufficient separation could not be achieved. The result is
It shows in Table 1 and Table 2.

[Comparative Example 9] As the aqueous cleaning liquid supplied at the time of phase inversion, recycling of the aqueous cleaning liquid separated in the stationary separation tank was used, the supply rate was 36 liter / hr, and the aqueous phase ratio was 30% by volume. Further, the same procedure as in Example 4 was performed except that the stirring was not performed. No oil-in-water dispersed phase formed. The results are shown in Tables 1 and 2.

[Example 9] In Example 4, the Na content in the organic solvent solution of the crude polycarbonate which had been acid washed,
When the Fe content was measured, it was 1 ppm by weight,
Since it was 8 ppm by weight, it was decided to further wash this with pure water. Pure water washing was performed under the same conditions as in Example 1 shown in Table 1. As a result, the time required for the separation is 3
Minutes, the Na content and Fe content in the organic solvent solution phase are reduced to 0.05 ppm by weight and 0.01 ppm by weight, respectively.
Further, the water content was reduced to 1,900 ppm by weight.
Ion chromatography method (ICP manufactured by Yokogawa Electric Corporation)
S-9000 type, column: ICS-C15 type). Further, the Fe content is measured by an atomic absorption method (Hitachi Z8100 type, light source: Hitachi hollow cathode lamp HLA).
-4 type). The results are shown in Tables 1 and 2.

[Example 10] A static mixer (Sulzer static mixer manufactured by Sumitomo Heavy Industries, Ltd., inner diameter 10 mmφ, element number 8) was used as a mixer for phase inversion, and stirring power was 0.027 kW · hr / m ³ Example 9 was repeated except that The results are shown in Table 1.
And Table 2.

[Embodiment 11] The line mixer rotation speed at the time of cleaning was 4000 rpm, the pure water supply rate was 35 liters / hr, the water phase ratio was 15% by volume, and a line mixer was used as a mixer at the time of phase inversion. Is used and its rotation speed is 80
Example 9 was carried out in the same manner as in Example 9 except that 0 rpm was used and that the aqueous cleaning liquid supplied at the time of phase inversion was recycled of the aqueous cleaning liquid separated in the stationary separation tank, and the supply rate was 98 liters / hr. . The results are shown in Tables 1 and 2.

[Comparative Example 10] An orifice was used as a mixer for phase inversion, and stirring power was 0.544 kW · hr /
Washing with pure water was performed in the same manner as in Example 9 except that m ³ was used. As a result, it was found that if the stirring power at the phase inversion was large, the cleaning property and the separability were deteriorated. The results are shown in Tables 1 and 2.

[Comparative Example 11] Pure water cleaning was performed in the same manner as in Comparative Example 10 except that the line mixer rotation speed at the time of cleaning was 4,000 rpm. The results are shown in Tables 1 and 2.

[Comparative Example 12] A line mixer was used as a mixer at the time of phase inversion, and the stirring power was 0.143 kW · h.
Example 9 was carried out in the same manner as in Example 9 except that r / m ³ was used. The results are shown in Tables 1 and 2.

[Comparative Example 13] An orifice was used as a mixer for phase inversion, and stirring power was 0.0054 kW · hr.
The same procedure as in Example 9 was carried out except that / m ³ was used. The stirring power was low, the aqueous washing liquid added at the time of phase inversion was not sufficiently mixed, and the water-in-oil type dispersed phase and the oil-in-water type dispersed phase coexisted, and sufficient separation could not be achieved. The results are shown in Tables 1 and 2.

[Comparative Example 14] Pure water was washed in the same manner as in Example 9 except that the line mixer rotation speed at the time of washing was 4,000 rpm and stirring was not performed at the time of phase inversion. No oil-in-water dispersed phase formed. The results are shown in Tables 1 and 2.

[0058]

[Table 1]

[0059]

[Table 2]

[0060]

EFFECT OF THE INVENTION According to the method for cleaning a polycarbonate organic solvent solution according to the present invention, a stirring power for forming a fine dispersed droplet size is applied to form a water-in-oil type dispersed phase, Impurities in the polycarbonate organic solvent solution are efficiently eluted into the aqueous cleaning solution that is the dispersed phase, and then the required amount of the aqueous cleaning solution is added, and it is sufficient to invert this and the polycarbonate organic material after phase separation is added. By applying a stirring power in the vicinity of which the amount of water in the solvent solution is minimized to form an oil-in-water type dispersed phase, the liquid separation property can be improved more and the time required for liquid separation can be shortened.

By using a stationary separation tank as the separation tank, the equipment cost can be minimized, and
The time required for separation can also be reduced by combining with the above-mentioned washing method. This makes it possible to efficiently wash the polycarbonate organic solvent solution for producing a polycarbonate resin raw material having excellent heat stability, steam resistance, transparency, and the like.

[Brief description of drawings]

[Figure 1]

[Explanation of symbols]

FIG. 1 is a schematic diagram showing an example of an apparatus used for implementing the present invention. 1 ... Crude polycarbonate organic solvent solution introduction tube, 2
... Aqueous cleaning liquid introduction pipe, 3 ... Line mixer, 4
... Aqueous cleaning liquid supply pipe, 5 ... Separated water recycling system, 6 ... Orifice mixer or static mixer, 7 ... Stationary separation tank, 8 ... Aqueous cleaning liquid phase,
9 ... Organic solvent solution phase, 10 ... Transport pump, 11
... Exhaust pipe to drainage system, 12 ... Supply pipe to the next process.

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[Procedure amendment]

[Submission date] December 12, 1995

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Brief description of drawings

[Correction method] Change

[Correction contents]

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an example of an apparatus used to practice the present invention.

[Explanation of symbols] 1 ... Crude polycarbonate organic solvent solution introducing pipe, 2
... Aqueous cleaning liquid introduction pipe, 3 ... Line mixer, 4
... Aqueous cleaning liquid supply pipe, 5 ... Separated water recycling system, 6 ... Orifice mixer or static mixer, 7 ... Stationary separation tank, 8 ... Aqueous cleaning liquid phase,
9 ... Organic solvent solution phase, 10 ... Transport pump, 11
... Exhaust pipe to drainage system, 12 ... Supply pipe to the next process.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Eizo Saito 1 Inezaki Kaigan, Ichihara-shi, Chiba Idemitsu Petrochemical Co., Ltd. (72) Inventor Hiroshi Tanaka 1 1 Anesaki Kaigan, Ichihara-shi, Chiba Idemitsu Petrochemical Co., Ltd. Within

Claims (5)

[Claims] 1. A method for cleaning a polycarbonate organic solvent solution containing impurities using an aqueous cleaning solution,
(1) The polycarbonate organic solvent solution and the aqueous cleaning solution are mixed so that the aqueous phase ratio is 1 to 40% by volume, and the resulting dispersed droplets are stirred with stirring power such that the particle diameter is 100 μm or less, A first step of forming a water-in-oil type dispersed phase, and (2) then further adding a necessary amount of an aqueous cleaning liquid to the mixture so that the water phase ratio becomes 15 to 90% by volume,
Second, a phase is changed to an oil-in-water type dispersed phase by stirring with a stirring power in the vicinity that is sufficient for phase inversion and minimizes the amount of water in the polycarbonate organic solvent solution after phase separation.
A method for cleaning a polycarbonate organic solvent solution, which comprises a step and (3) a separation step of separating the polycarbonate organic solvent solution phase and the aqueous cleaning liquid phase. 2. The polycarbonate concentration is 6 to 30% by weight.
A method of washing a polycarbonate organic solvent solution containing impurities in the range of
The polycarbonate organic solvent solution and the aqueous cleaning solution were mixed so as to have an aqueous phase ratio of 1 to 40% by volume, and the mixture was mixed with water.
The first step of forming a water-in-oil type dispersed phase by stirring with a stirring power exceeding 1 kW · hr / m ³ , and (2) Next, it is necessary that the mixture has an aqueous phase ratio of 15 to 90% by volume. An additional amount of aqueous wash solution is added, which is 0.01-0.1
From the second step of stirring with stirring power in the range of 0 kW · hr / m ³ to invert the oil-in-water dispersed phase, and (3) after that, the separation step of separating the polycarbonate organic solvent solution phase and the aqueous cleaning liquid phase A method for cleaning a polycarbonate organic solvent solution, comprising: 3. The method for cleaning a polycarbonate organic solvent solution according to claim 1, wherein the separation step of separating the polycarbonate organic solvent solution phase and the aqueous cleaning liquid phase is a stationary separation method. 4. The method for cleaning a polycarbonate organic solvent solution according to claim 1, wherein the stirring means is a line mixer, an orifice mixer or a static mixer. 5. The polycarbonate organic material according to claim 1, wherein all or part of the aqueous cleaning liquid separated in the separation step is recycled and used as the aqueous cleaning liquid in the second step. Method for cleaning solvent solution.