JP2001329059A - Method for recovering amine catalyst - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for efficiently recovering an amine catalyst used in the production of a polycarbonate and a method for producing a good quality polycarbonate resin by using the recovered catalyst. SOLUTION: Provided are a method for recovering an amine catalyst from an organic solvent solution of a polycarbonate resin produced by interfacial polymerization using an amine catalyst, which method comprises the steps of: (1) extracting an amine catalyst from an organic solvent solution of a polycarbonate solution after the polymerization with an aqueous acid solution, (2) adjusting the pH of the aqueous extract to 7.5-14 by the addition of an alkali thereto, and (3) extracting the amine catalyst from the obtained aqueous solution of a pH of 7.5-14 with an organic solution and a method for producing a polycarbonate resin comprising using the recovered amine catalyst as a catalyst in the production of a polycarbonate resin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for recovering an amine catalyst, and more particularly, to a method for recovering an amine catalyst having an excellent recovery rate and a good purity of the recovered amine catalyst, a hue using the recovered amine catalyst, The present invention relates to a method for producing a polycarbonate resin having good heat resistance.

[0002]

2. Description of the Related Art Polycarbonate resins are widely used in optical fields such as electric fields, automobile fields, food fields, and multimedia recording media because of their excellent properties such as optical properties, mechanical properties, and electrical properties. , Its demand tends to increase year by year. The production of polycarbonate resin has been increasing to meet the demand.

[0003] As a method for producing a polycarbonate resin, an interfacial polycondensation reaction is mainly employed, and in this case, an amine catalyst is often used for the polycondensation reaction. At this time, the amine-based catalyst used is dissolved and remains in the organic solvent solution of the polycarbonate resin after the completion of the polymerization reaction, and if the amine-based catalyst remains in the organic solvent solution, the hue and heat resistance of the polycarbonate resin deteriorate. Therefore, usually, an acidic aqueous solution is added to and mixed with an organic solvent solution, and the amine-based catalyst in the organic solvent solution is extracted with the acidic aqueous solution, and the amine-based catalyst in the organic solvent solution is removed. A method of neutralizing an extracted acidic aqueous solution with an alkali and disposing it in a river or sea as factory wastewater is used.

[0004] However, the amount of spent amine catalyst remaining in the factory effluent increases proportionately with the increase in the production of polycarbonate resin, and is not only environmentally friendly but also economical. Not preferred. Therefore, it is desired to develop a method for efficiently recovering the amine catalyst used in the production of the polycarbonate resin with a reusable purity.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for efficiently recovering an amine-based catalyst used for an interfacial polycondensation reaction of a polycarbonate resin, and to provide a high-quality polycarbonate resin using the recovered amine-based catalyst. Is to provide a method for producing the same.

The present inventors have conducted intensive studies to achieve the above object. As a result, the organic solvent solution of the polycarbonate resin containing the amine catalyst after the completion of the interfacial polycondensation reaction was subjected to an acidic aqueous solution extraction step and an alkali addition step. Surprisingly, high-purity amine-based catalysts can be efficiently recovered by treating in the order of the organic solvent extraction step and, if necessary, the distillation step, and further using the recovered amine-based catalyst. The inventors have found that the obtained polycarbonate resin has the same quality as a polycarbonate resin produced using a commercially available high-purity amine-based catalyst, and have reached the present invention.

[0007]

That is, according to the present invention, a polycarbonate resin is produced by an interfacial polymerization method using an amine catalyst, and the amine catalyst is recovered from an organic solvent solution of the polycarbonate resin after completion of the polymerization. The method comprises the following steps: (1) a step of extracting an amine-based catalyst with an acidic aqueous solution from an organic solvent solution of a polycarbonate resin after completion of polymerization (Step A); (2) adding an alkali to the extracted aqueous solution;
(B) and (3) extracting the amine catalyst with an organic solvent from the obtained aqueous solution having a pH of 7.5 to 14 (C). The present invention provides a method for recovering an amine-based catalyst and a method for producing a polycarbonate resin using the thus recovered amine-based catalyst as an interfacial polycondensation reaction catalyst.

In the recovery method of the present invention, the target amine catalyst has a normal-pressure boiling point exceeding the interfacial polycondensation reaction temperature of the polycarbonate resin and preferably not higher than 98 ° C., preferably in the range of 30 ° C. to 98 ° C. Is more preferred. Specifically, tertiary amines such as trimethylamine and triethylamine are preferable, and triethylamine (normal pressure boiling point: 89.4 ° C.) is particularly preferably used. When the normal pressure boiling point of the amine catalyst is within the above range, the catalyst does not evaporate during the polymerization reaction, and the equipment is simple and high in distillation and recovery of the amine catalyst as necessary. A pure amine catalyst is preferable because it can be easily recovered efficiently.

According to the present invention, a polycarbonate resin is produced by an interfacial polycondensation reaction using an amine catalyst, and an organic solvent solution of a polycarbonate resin containing an amine catalyst after polymerization is subjected to the following steps A to C: The amine catalyst can be efficiently recovered from such an organic solvent solution by performing the above treatment. Hereinafter, each step will be described.

Step A: In this step, the amine catalyst is acid-extracted from the organic solvent solution of the polycarbonate resin after the completion of the interfacial polycondensation reaction with an acidic aqueous solution. An acidic aqueous solution is added to the organic solvent solution of the polycarbonate resin after the polymerization, and the mixture is stirred and mixed.The organic solvent solution and the acidic aqueous solution are allowed to stand still or separated by a centrifugal separator, etc. The amine-based catalyst is extracted into the acidic aqueous solution. Here, as the acid used for the acid extraction, both an inorganic acid and an organic acid are used. For example, phosphoric acid, acetic acid, sulfuric acid, hydrochloric acid and the like are preferable, and sulfuric acid and hydrochloric acid are particularly preferably used.

The pH of the acidic aqueous solution used for acid extraction is 6
The following are preferred, pH 1.2 to 6 are more preferred, and pH
2-4 are more preferred. When an acidic aqueous solution within such a range is used, the amount of alkali used in the next step B becomes an appropriate amount, and the amine catalyst is sufficiently extracted from the organic solvent solution of the polycarbonate resin, and the hue and heat resistance of the obtained polycarbonate resin are obtained. It is preferable because the properties are good.

The amount of the acidic aqueous solution used for the acid extraction is preferably 0.1 to 20 parts by volume, more preferably 0.2 to 10 parts by volume, more preferably 0.1 to 10 parts by volume, per 1 part by volume of the organic solvent solution of the polycarbonate resin. 2 to 5.0 volume parts is more preferable,
0.2 to 4.0 volume parts is particularly preferred. When the water content of the acidic aqueous solution is used in the range of 0.1 to 20 parts by volume with respect to 1 part by volume of the polycarbonate resin organic solvent solution, the amine-based catalyst is sufficiently extracted from the organic solvent solution to obtain the polycarbonate resin. Is preferable because the hue and heat resistance of the resin are good, and the amount of alkali used in the step B is suitable.

Step B: In this step, an alkali is added to the acid-extracted aqueous solution obtained in Step A, and the aqueous solution is adjusted to pH.
This is a step of adjusting the value to 7.5 to 14. In the step B, the amine catalyst dissolved in the acid is released by adding an alkali.

Examples of the alkali used include alkali metal compounds such as sodium hydroxide and potassium hydroxide, and alkaline earth metal compounds such as calcium hydroxide, barium hydroxide and magnesium hydroxide. Is preferably used. These can be used as they are or as aqueous solutions. The pH of the aqueous solution after the addition of the alkali is 7.5 to 14, and the pH is 9 to 14.
13.8 is preferable, and pH 10-13.5 is more preferable. If the pH of the aqueous solution after the addition of the alkali is less than 7.5, the recovery of the amine-based catalyst decreases, which is not preferable. When a large amount of alkali is added, the amount of acid used when neutralizing and draining the aqueous solution after the extraction of the amine-based catalyst in the step C becomes large, which may be industrially disadvantageous.

Step C: In this step, the amine catalyst is extracted from the aqueous solution having a pH of 7.5 to 14 obtained in Step B with an organic solvent. After adding an organic solvent to the alkaline aqueous solution obtained in the step B and stirring and mixing,
The amine catalyst in the alkaline aqueous solution is extracted into the organic solvent by allowing the organic solvent solution and the alkaline aqueous solution to stand still or to be separated by a centrifuge or the like.

Here, the organic solvent used for the organic solvent extraction includes methylene chloride, chloroform, 1,2-dichloroethane, 1,1-dichloroethane, bromoethane,
Halogenated hydrocarbons such as butyl chloride, chloropropane and chlorobenzene are mentioned, and methylene chloride is particularly preferably used. These solvents are used alone or in combination of two or more. The amount of the organic solvent used is preferably 0.001 to 3.0 parts by volume with respect to the aqueous solution having a pH of 7.5 to 14 obtained in the step B, and 0.001 to 3.0 parts by volume.
2.0 parts by volume is more preferable, 0.001 to 1.5 parts by volume is more preferable, and 0.002 to 1.0 parts by volume is particularly preferable. When the amount of the organic solvent is used within the above range,
The extraction efficiency is also good, and the heat energy at the time of distillation in the next step D, which is carried out as required, does not become large, and the operation is simple and preferable, which is preferable. The amine-based catalyst extracted with the organic solvent has high purity, and can be reused as a solution as it is as an interfacial polycondensation reaction catalyst when producing a polycarbonate resin.

Further, in the present invention, if necessary, a step (step D) of distilling the organic solvent solution containing the amine catalyst obtained in the above step C to separate the amine catalyst can be carried out. In the step D, the amine catalyst dissolved in the organic solvent is separated and recovered by distillation.
As a distillation apparatus to be used, a rectification column such as a packed column or a tray column is preferably used. The reflux ratio in distillation is 0.2
5 is preferable, and 1-4 is more preferable. When distillation is performed at a reflux ratio in such a range, an amine catalyst having high purity is easily obtained, and a large amount of heat energy is not required, and the operation is simple and industrially preferable. In the distillation of the organic solvent solution, there may be no particular problem if the aqueous solution partially contains, but it is preferable that the amount of the aqueous solution is small.

The amine catalyst recovered according to the present invention has high purity and can be reused as an interfacial polycondensation reaction catalyst during the production of a polycarbonate resin. The polycarbonate resin produced using the recovered amine catalyst has the same quality as a polycarbonate resin produced using a commercially available high purity amine catalyst.

The polycarbonate resin to be used in the present invention is obtained by reacting a dihydric phenol with a carbonate precursor by an interfacial polycondensation method. Representative examples of the dihydric phenol used here include hydroquinone, resorcinol, 4,4'-dihydroxydiphenyl, bis (4-hydroxyphenyl) methane, bis {(4-hydroxy-3,5-dimethyl) Phenyl @ methane, 1,1-bis (4-hydroxyphenyl) ethane, 1,1-bis (4-hydroxyphenyl) -1-phenylethane, 2,2-bis (4-hydroxyphenyl) propane (commonly known as bisphenol A ), 2,2-bis {(4-hydroxy-3-methyl) phenyl} propane, 2,2-bis {(4-hydroxy-3,5-dimethyl) phenyl} propane, 2,2-bis} (3 , 5-Dibromo-4-hydroxy) phenyl} propane, 2,2
-Bis {(3-isopropyl-4-hydroxy) phenyl} propane, 2,2-bis} (4-hydroxy-3-
Phenyl) phenyl} propane, 2,2-bis (4-hydroxyphenyl) butane, 2,2-bis (4-hydroxyphenyl) -3-methylbutane, 2,2-bis (4
-Hydroxyphenyl) -3,3-dimethylbutane,
2,4-bis (4-hydroxyphenyl) -2-methylbutane, 2,2-bis (4-hydroxyphenyl) pentane, 2,2-bis (4-hydroxyphenyl) -4-
Methylpentane, 1,1-bis (4-hydroxyphenyl) cyclohexane, 1,1-bis (4-hydroxyphenyl) -4-isopropylcyclohexane, 1,1-
Bis (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane, 9,9-bis (4-hydroxyphenyl) fluorene, 9,9-bis {(4-hydroxy-3-methyl) phenyl} fluorene, α , Α'-bis (4-hydroxyphenyl) -o-diisopropylbenzene, α, α'-bis (4-hydroxyphenyl) -m
-Diisopropylbenzene, α, α'-bis (4-hydroxyphenyl) -p-diisopropylbenzene, 1,
3-bis (4-hydroxyphenyl) -5,7-dimethyladamantane, 4,4'-dihydroxydiphenyl ketone, 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxydiphenyl ester, etc., which are used alone Alternatively, two or more kinds can be used in combination.

Among these, bisphenol A, 2,2-bis {(4-hydroxy-3-methyl) phenyl} propane, 2,2-bis (4-hydroxyphenyl) butane,
2,2-bis (4-hydroxyphenyl) -3-methylbutane, 2,2-bis (4-hydroxyphenyl)-
3,3-dimethylbutane, 2,2-bis (4-hydroxyphenyl) -4-methylpentane, 1,1-bis (4
A homopolymer obtained from at least one bisphenol selected from the group consisting of -hydroxyphenyl) -3,3,5-trimethylcyclohexane and α, α'-bis (4-hydroxyphenyl) -m-diisopropylbenzene, or Copolymers are preferred. In particular, bisphenol A homopolymer and 1,1-bis (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane and bisphenol A, 2,2-bis {(4-hydroxy- Copolymers with 3-methyl) phenyl} propane or α, α′-bis (4-hydroxyphenyl) -m-diisopropylbenzene are preferably used.

As the carbonate precursor, carbonyl halide or haloformate is used, and specific examples include phosgene or dihaloformate of dihydric phenol.

In producing the polycarbonate resin by reacting the dihydric phenol with the carbonate precursor by an interfacial polycondensation method, usually a catalyst, a terminal terminator, an antioxidant for the dihydric phenol and the like are appropriately used. You. Also,
The polycarbonate resin may be a branched polycarbonate resin obtained by copolymerizing a trifunctional or higher polyfunctional aromatic hydroxy compound, or a polyester carbonate resin obtained by copolymerizing an aromatic or aliphatic bifunctional carboxylic acid, Further, a mixture of two or more of the obtained polycarbonate resins may be used.

The reaction by the interfacial polycondensation method is usually a reaction between dihydric phenol and phosgene, and is carried out in the presence of an acid binder, a catalyst and an organic solvent.

As the acid binder, for example, an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide or an amine compound such as pyridine is used.

Examples of the organic solvent include methylene chloride,
Halogenated hydrocarbons such as chloroform, 1,2-dichloroethane, 1,1-dichloroethane, bromoethane, butyl chloride, chloropropane, and chlorobenzene are used, and methylene chloride is particularly preferably used.
These solvents are used alone or in combination of two or more.

Examples of the amine catalyst used for accelerating the reaction include tertiary amines such as triethylamine, tetra-n-butylammonium bromide, tetra-n-butylphosphonium bromide, quaternary ammonium compounds, and quaternary ammonium compounds. And a catalyst such as a secondary phosphonium compound. Triethylamine is particularly preferably used.

The reaction temperature by the interfacial polycondensation method is usually 0 to 4
It is preferable that the reaction temperature is 0 ° C., the reaction time is about 10 minutes to 5 hours, and the pH during the reaction is 9 or more.

In such a polymerization reaction, a terminal stopper is usually used. Monofunctional phenols can be used as such a terminal stopper. Monofunctional phenols are generally used as a terminating agent for controlling the molecular weight, and the obtained polycarbonate resin has a terminal blocked by a group derived from the monofunctional phenol, so that it is compared with the non-functional one. And excellent thermal stability.
Such a monofunctional phenol is generally a phenol or a lower alkyl-substituted phenol, and may be a monofunctional phenol represented by the following formula (1).

[0029]

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Wherein A is a hydrogen atom, a linear or branched alkyl or arylalkyl group having 1 to 9 carbon atoms, and r is an integer of 1 to 5, preferably 1 to 3. ]

Specific examples of the above monofunctional phenols include phenol, p-tert-butylphenol, p-cumylphenol and isooctylphenol.

Further, other monofunctional phenols include:
Phenols or benzoic acid chlorides having a long-chain alkyl group or an aliphatic polyester group as a substituent, or long-chain alkyl carboxylic acid chlorides can be used. When blocked, they not only function as a terminal terminator or a molecular weight regulator, but also improve the melt flowability of the resin and facilitate not only the molding process, but also the physical properties particularly as an optical disk substrate, especially the resin. It has the effect of lowering the water absorption and the effect of reducing the birefringence of the substrate, and is preferably used. Among them, phenols having a long-chain alkyl group represented by the following formulas (2) and (3) as a substituent are preferably used.

[0033]

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[0034]

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[Wherein X is -RO-, -R-CO-O
— Or —RO—CO—, wherein R represents a single bond or a divalent aliphatic hydrocarbon group having 1 to 10, preferably 1 to 5 carbon atoms, and n represents an integer of 10 to 50. Show. ]

As the substituted phenols of the formula (2), those wherein n is 10 to 30, especially 10 to 26 are preferred.
Specific examples thereof include decylphenol, dodecylphenol, tetradecylphenol, hexadecylphenol, octadecylphenol, eicosylphenol, docosylphenol, and tricontylphenol.

As the substituted phenols of the formula (3), compounds wherein X is -R-CO-O- and R is a single bond are suitable, and n is 10-30, especially 10-26. Those are preferred, and specific examples thereof include decyl hydroxybenzoate, dodecyl hydroxybenzoate, tetradecyl hydroxybenzoate, hexadecyl hydroxybenzoate, eicosyl hydroxybenzoate, docosyl hydroxybenzoate and tricontyl hydroxybenzoate. .

It is desirable that these terminal stoppers are introduced at least at 5 mol%, preferably at least 10 mol%, based on all terminals of the obtained polycarbonate resin. Or a mixture of two or more.

The molecular weight of the polycarbonate resin is determined based on the viscosity average.
10,000 to 100,000 is preferable in terms of the average molecular weight (M).
Preferably, 12,000 to 50,000 is more preferable.
3,000 to 30,000 are particularly preferred. Such viscosity
Polycarbonate resin with average molecular weight has sufficient strength
And the melt fluidity during molding is good.
This is preferable because shape distortion does not occur. Such a viscosity average molecular weight is a salt
0.7 g of polycarbonate resin in 100 ml of methylene chloride
Was determined from a solution in which was dissolved at 20 ° C. (η _sp) To
It is obtained by inserting it into the equation. η_sp/C=[η]+0.45×[η]^Twoc (however, [η]
Is the limiting viscosity) [η] = 1.23 × 10^-FourM^0.83 c = 0.7

The solution of the polycarbonate resin in the organic solvent obtained by the above-mentioned production method is subjected to the acid extraction treatment in the step A, whereby the amine catalyst is extracted into an acidic aqueous solution.

The organic solvent solution of the polycarbonate resin subjected to the acid extraction treatment is usually washed with water. Washing of the organic solvent solution with water is preferably performed with an electric conductivity of, for example, ion-exchanged water of 10 μS / cm or less, more preferably 1 μS / cm.
This is performed with the following water, and after mixing and stirring such an organic solvent solution and water, the organic solvent solution phase and the aqueous phase are separated by standing or using a centrifuge, and the organic solvent solution is separated. The phase is removed repeatedly to remove water-soluble impurities. By performing water washing, water-soluble impurities are removed, and the hue of the obtained polycarbonate resin becomes favorable.

It is preferable that the organic solvent solution removes foreign matters which are insoluble impurities. As a method of removing the foreign matter, a method of filtering or a method of treating with a centrifuge is preferably employed.

In the method of filtering an organic solvent solution, the filter used for filtration is a material that can withstand the organic solvent solution, for example, a material such as cellulose, ceramic, polyolefin resin, and metal such as copper and stainless steel. One. Also, the pore size of the filter is 0.
3-5 μm is preferred, 0.3-2 μm is more preferred, 0.3-1.5 μm is still more preferred, and 0.3-1 μm is preferred.
μm is particularly preferred. When the pore size of the filter is in the above range, the filtration efficiency is appropriate, and the amount of foreign substances in the polycarbonate resin is sufficiently reduced, so that the filter is preferably used.

In the method of treating an organic solvent solution with a centrifuge, the centrifugal force is preferably in the range of 500 to 15000G. When the content is within such a range, the amount of foreign substances in the organic solvent solution can be extremely reduced, and the material can be easily selected from the viewpoint of mechanical strength.

The organic solvent solution can be obtained by removing the solvent to obtain solids of powder and granules, and drying the solids to obtain polycarbonate resin powders. More preferably, the solids are melted. Extrude and pelletize. The pellets are preferably provided for molding.

The polycarbonate resin obtained according to the present invention includes flame retardants, heat stabilizers (phosphate esters, phosphite esters, etc.), release agents, antistatic agents, ultraviolet absorbers, antioxidants, dyes and pigments. Coloring agents, antibacterial agents, reinforcing agents such as glass fibers and carbon fibers, and other resins can be appropriately added and used.

The polycarbonate resin obtained by using the amine catalyst recovered by the recovery method of the present invention has no difference in quality such as hue and thermal stability from the ordinary polycarbonate resin, and is equivalent to the ordinary polycarbonate resin. , Such as optics, precision instruments, automobiles and foods.

[0048]

EXAMPLES The present invention will be described below in detail with reference to examples, but the present invention is not limited to these examples. The evaluation was performed by the following method.

(1) Viscosity average molecular weight of the polycarbonate resin 0.7 g of the polycarbonate resin was added to 100 m of methylene chloride.
1) and determined from the specific viscosity measured at 20 ° C.

(2) Catalyst recovery The catalyst recovery was calculated from the following equation. Catalyst recovery rate (% by weight) = (amount of triethylamine obtained after distillation) / (amount of triethylamine used in polymerization reaction) × 100

(3) Catalyst Purity Triethylamine was purified by GC (Hitachi 263-70, column: PEG-20).
M) and analyzed from the gas chromatogram.

(4) Hue (b value) The obtained polycarbonate resin pellets were injected into an injection molding machine (Nihon Steel Works Co., Ltd .: Nikko Anchor V-17-65).
After plasticizing at a cylinder temperature of 340 ° C., a 50 mm square plate having a thickness of 2 mm was formed. The b value of the molded plate was measured using a color difference meter (manufactured by Nippon Denshoku Co., Ltd.).

(5) Thermal stability (ΔE) The obtained polycarbonate resin pellets were injected into an injection molding machine (Nihon Steel Works Co., Ltd .: Nikko Anchor V-17-65).
The test piece (50 mm with a thickness of 2 mm) was kept at a cylinder temperature of 340 ° C. for 10 minutes.
m square plate), and the change in hue (ΔE) thereof was measured. Hue change is measured by a color difference meter (Nippon Denshoku Co., Ltd.)
The L, a, and b values were measured using the following formula, and were calculated using the following equations. ΔE = [(L′−L) ² + (a′−a) ² + (b′−b)
² ] ^1/2 (L, a, b are not retained, L ', a', b 'are retained for 10 minutes)

Reference Example 1 In a reactor equipped with a thermometer, a stirrer and a reflux condenser, 219.4 parts of ion-exchanged water, 48% by weight were used.
40.2 parts of an aqueous sodium hydroxide solution were charged, and 2,2-bis (4-hydroxyphenyl) propane was added thereto.
After dissolving 5 parts and 0.12 parts of hydrosulfite, 181 parts of methylene chloride is added, and the mixture is stirred at 15 to 25 ° C.
Injected 28.3 parts of phosgene for 40 minutes. After completion of the phosgene blowing, 7.2 parts of a 48% by weight aqueous sodium hydroxide solution and p-tert-butylphenol 2.4 were used.
Add 2 parts, start stirring, and after emulsification, commercial purity 99.9%
0.06 parts of triethylamine, and then 28 to 3
The reaction was completed by stirring at 3 ° C. for 1 hour. After the completion of the reaction, the product was diluted by adding 400 parts of methylene chloride.

The pH was added to 495 parts by volume of this methylene chloride solution.
Triethylamine was extracted with acid by adding 150 parts by volume of a 3.0 hydrochloric acid aqueous solution, and then the methylene chloride solution was washed with ion-exchanged water. When the conductivity of the aqueous phase became almost the same as that of the ion-exchanged water, the chloride was removed. SUS304 with methylene solution
Was filtered with a filter having a pore size of 1 μm.

Next, the methylene chloride solution of the polycarbonate resin was dropped into hot water at 75 ° C. in a kneader provided with an isolation chamber having a foreign substance take-out port at the bearing portion, and the polycarbonate resin was flaked while distilling off the methylene chloride. did. Next, the liquid-containing polycarbonate resin is pulverized,
After drying at 45 ° C. for 4 hours, a powder having a viscosity average molecular weight of 15,000 was obtained. To this powder, 0.01% by weight of trisnonylphenyl phosphite, 0.01% by weight of trimethyl phosphate, and 0.1% by weight of monoglyceride stearate were added and mixed. Next, using a vent-type twin-screw extruder [KTX-46 manufactured by Kobe Steel Co., Ltd.], the cylinder temperature was 260 ° C. and the degree of vacuum was 0.67 kPa (5 mm).
The mixture was melt-kneaded while degassing with Hg) to obtain pellets. The results of evaluation using these pellets are shown in Table 1.

Reference Example 2 In Reference Example 1, p-te
Pellets were obtained in the same manner as in Reference Example 1, except that the amount of rt-butylphenol was changed to 1.55 parts and the cylinder temperature of the vented twin-screw extruder was changed to 280 ° C. The results of evaluation using these pellets are shown in Table 1.

Example 1 To 495 parts by volume of a methylene chloride solution obtained by adding 400 parts of methylene chloride to the product obtained after the completion of the reaction obtained in Reference Example 1, 150 parts by volume of a hydrochloric acid aqueous solution having a pH of 3.0 was added. The mixture was stirred and mixed, and triethylamine in the methylene chloride solution was acid-extracted. After mixing, the solution was allowed to stand to separate the methylene chloride solution and the aqueous hydrochloric acid solution, and the aqueous hydrochloric acid solution was taken out (Step A). Next, a 48% by weight aqueous sodium hydroxide solution was added to the aqueous hydrochloric acid solution to adjust the pH of the aqueous solution to 13 (step B). A 0.05 volume ratio of methylene chloride was added to the aqueous alkali solution, and the mixture was stirred and mixed, and triethylamine in the aqueous alkali solution was extracted with methylene chloride. After mixing, the aqueous alkali solution and the methylene chloride solution were separated by a centrifuge to obtain a methylene chloride solution (Step C). This methylene chloride solution was distilled at a reflux ratio of 3 using a rectification column having 9 stages to obtain triethylamine having a purity of 99.0%. (Step D). The recovery of triethylamine was 92% by weight. Further, using 0.061 parts of the obtained triethylamine, a polycarbonate resin was produced in the same manner as in Reference Example 1 to obtain pellets. The results of evaluation using these pellets are shown in Table 1.

[Example 2] In step B of Example 1,
Triethylamine was obtained in the same manner as in Example 1 except that the aqueous solution was adjusted to pH 10 by adding a 48% by weight aqueous sodium hydroxide solution. This triethylamine has a purity of 9
9.0%, and the recovery was 91% by weight. Further, using 0.061 parts of the obtained triethylamine, a polycarbonate resin was produced in the same manner as in Reference Example 1 to obtain pellets. The results of evaluation using these pellets are shown in Table 1.

Example 3 In step A of Example 1,
Triethylamine was obtained in the same manner as in Example 1 except that 150 parts by volume of a hydrochloric acid aqueous solution having a pH of 5.5 was added.
The triethylamine had a purity of 99.0%, and the recovery was 92% by weight. Further, using 0.061 parts of the obtained triethylamine, a polycarbonate resin was produced in the same manner as in Reference Example 1 to obtain pellets. The results of evaluation using these pellets are shown in Table 1.

Example 4 A 495 volume part of a methylene chloride solution diluted by adding 400 parts of methylene chloride to the product obtained after the reaction obtained in Reference Example 2 was used. Triethylamine was obtained in the same manner as in Example 1, except that 1.0 volume ratio of methylene chloride was added. The triethylamine had a purity of 99.0%, and the recovery was 92% by weight. Further, using 0.061 part of the obtained triethylamine, Reference Example 2
A polycarbonate resin was produced in the same manner as described above to obtain pellets. The results of evaluation using these pellets are shown in Table 1.

Example 5 In the step B, 495 parts by volume of a methylene chloride solution diluted by adding 400 parts of methylene chloride to the product obtained after the completion of the reaction obtained in Reference Example 2 was used. Triethylamine was obtained in the same manner as in Example 1 except that the pH of the aqueous solution was adjusted to 10 by adding a sodium aqueous solution. The triethylamine had a purity of 99.0%, and the recovery was 91% by weight.
Furthermore, a polycarbonate resin was produced in the same manner as in Reference Example 2 using 0.061 parts of the obtained triethylamine, and pellets were obtained. The results of evaluation using these pellets are shown in Table 1.

Example 6 To the product after completion of the reaction obtained in Reference Example 2 was used 495 parts by volume of a methylene chloride solution diluted by adding 400 parts of methylene chloride. In Step A, hydrochloric acid having a pH of 5.5 was used. Triethylamine was obtained in the same manner as in Example 1, except that 150 parts by volume of the aqueous solution was added. The triethylamine had a purity of 99.0%, and the recovery was 92% by weight. Furthermore, a polycarbonate resin was produced in the same manner as in Reference Example 2 using 0.061 parts of the obtained triethylamine, and pellets were obtained. The results of evaluation using these pellets are shown in Table 1.

Example 7 In the step C of Example 1,
The volume ratio of methylene chloride to the aqueous alkali solution was changed to 0.0025 volume ratio (0.5 parts of methylene chloride), and 0.55 of a methylene chloride solution having a triethylamine concentration of 10.0 wt%
5 parts were obtained (Step C). Triethylamine recovery rate is 9
2.5% by weight. A polycarbonate resin was produced in the same manner as in Reference Example 1 using 0.60 parts of a methylene chloride solution obtained by performing the above operation several times to obtain pellets. Table 2 shows the results of evaluation using the pellets.

Example 8 In the step C of Example 1,
The volume ratio of methylene chloride to the aqueous alkali solution was changed to 0.005 volume ratio (1.0 part of methylene chloride) to obtain 1.056 parts of a methylene chloride solution having a triethylamine concentration of 5.0% by weight (Step C). Triethylamine recovery is 92.5
% By weight. A polycarbonate resin was produced in the same manner as in Reference Example 1 using 1.20 parts of a methylene chloride solution obtained by performing the above operation several times, and pellets were obtained. Table 2 shows the results of evaluation using the pellets.

Example 9 In the step B of Example 1,
Add 48% aqueous sodium hydroxide to hydrochloric acid and add
In Step C, a methylene chloride solution was obtained in the same manner as in Step C of Example 8. This methylene chloride solution had a triethylamine concentration of 5.0% by weight and a methylene chloride solution amount of 1.056 parts. The triethylamine recovery was 92.5% by weight. A polycarbonate resin was produced in the same manner as in Reference Example 1 using 1.20 parts of a methylene chloride solution obtained by performing the above operation several times, and pellets were obtained. Table 2 shows the results of evaluation using the pellets.

Example 10 In step B of Example 1, a 48% aqueous solution of sodium hydroxide was added to an aqueous solution of hydrochloric acid to adjust the pH to 8, and in step C, a methylene chloride solution was prepared in the same manner as in step C of Example 7. Obtained. This methylene chloride solution had a triethylamine concentration of 9.75% by weight and a methylene chloride solution amount of 0.554 parts. The triethylamine recovery was 90.0% by weight. A polycarbonate resin was produced in the same manner as in Reference Example 1 using 0.62 parts of a methylene chloride solution obtained by performing the above operation several times, and pellets were obtained. Table 2 shows the results of evaluation using these pellets.
It was shown to.

[Comparative Example 1] In step B of Example 1,
Triethylamine was obtained in the same manner as in Example 1 except that the pH of the aqueous solution was adjusted to 7.0 by adding a 48% by weight aqueous sodium hydroxide solution. This triethylamine has a purity of 9
Although it was 9.0%, the recovery was 50% by weight or less. Further, using 0.061 parts of the obtained triethylamine, a polycarbonate resin was produced in the same manner as in Reference Example 1 to obtain pellets. The results of evaluation using these pellets are shown in Table 1.

[Comparative Example 2] In step A of Example 1,
Triethylamine was prepared in the same manner as in Example 1 except that 150 parts by volume of a hydrochloric acid aqueous solution having a pH of 6.5 was added, and in Step B, a 48% by weight aqueous sodium hydroxide solution was added to adjust the pH of the aqueous solution to 10. Obtained. Although the triethylamine had a purity of 99.0%, the recovery was 50% by weight or less. Further, the methylene chloride solution after the standing separation in the step A was treated in the same manner as in Reference Example 1 to obtain pellets. These pellets burn badly and b
The value and ΔE could not be measured.

[Comparative Example 3] In the A step, using 495 parts by volume of a methylene chloride solution obtained by adding 400 parts of methylene chloride to the product after completion of the reaction obtained in Reference Example 2 Except that 150 parts by volume of the aqueous solution was added and in the step B, a 48% by weight aqueous sodium hydroxide solution was added to adjust the pH of the aqueous solution to 10,
Triethylamine was obtained in the same manner as in Example 1. Although the triethylamine had a purity of 99.0%, the recovery was 50% by weight or less. Further, the methylene chloride solution after the standing separation in the step A was treated in the same manner as in Reference Example 2 to obtain pellets. These pellets burn badly,
The b value and ΔE could not be measured.

[0071]

[Table 1]

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[Table 2]

[0073]

The method for recovering an amine catalyst of the present invention can efficiently recover a high-purity amine catalyst, and is an excellent method from the viewpoint of environmental conservation or economy.
The polycarbonate resin obtained using the recovered amine catalyst is excellent in quality such as hue and thermal stability,
The industrial effects it produces are exceptional.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4J029 AA09 AB04 AB07 AC01 AD10 AE01 BB04A BB05A BB10A BB12A BB12B BB12C BB13A BB13B BB13C HA01 HC01 HC02 JB171 JC021 JC031 JC091 JD05 KE11 KH05

Claims (3)

[Claims] 1. A method in which a polycarbonate resin is produced by an interfacial polymerization method using an amine catalyst, and the amine catalyst is recovered from an organic solvent solution of the polycarbonate resin after completion of the polymerization. Step (A) of extracting an amine-based catalyst with an acidic aqueous solution from an organic solvent solution of the polycarbonate resin of (2), (2) adding an alkali to the extracted aqueous solution,
(B) and (3) extracting the amine catalyst with an organic solvent from the obtained aqueous solution having a pH of 7.5 to 14 (C). For recovering amine catalysts. 2. The amine-based catalyst according to claim 1, further comprising the step of: (4) distilling the organic solvent solution containing the amine-based catalyst obtained in the step C to separate the amine-based catalyst (step D). Catalyst recovery method. 3. A method for producing a polycarbonate resin, comprising using the amine catalyst recovered by the recovery method according to claim 1 as an interfacial polymerization catalyst in the production of a polycarbonate resin.