JP2000119388A - Production of aromatic polycarbonate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing an aromatic polycarbonate not causing quality deterioration excellent in hue and not including foreign matter. SOLUTION: This method for producing an aromatic polycarbonate comprises the following conditions: (1) maintaining the flow rate of reaction mixture in piping for the reaction mixture in a molten state to pass so as to have a prescribed value; (2) maintaining the reaction mixture so as to have >=1,000 viscosity average molecular weight; (3) maintaining the reaction mixture so as to have >=3 hours total of average residence time; (4) maintaining the wall surface temperature of the piping so as to become higher than that of the reaction mixture in the piping.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for producing an aromatic polycarbonate. More specifically, regarding a method for producing an aromatic polycarbonate by a melt polycondensation method,
The present invention relates to a production method capable of efficiently producing an aromatic polycarbonate which is excellent in hue stability, heat stability, and the like of an aromatic polycarbonate at the time of production, and is excellent in hue and transparency.

[0002]

2. Description of the Related Art Aromatic polycarbonate resins are widely known as very useful resins because of their excellent properties such as impact resistance and transparency. As a method for producing the aromatic polycarbonate resin, an interface method in which an aromatic dihydroxy compound and phosgene are reacted in a mixed solution of an organic solvent and an aqueous alkali solution, and an aromatic dihydroxy compound and a carbonic acid diester are used in the presence of a catalyst. There is a melt polycondensation method in which the reaction is carried out under high temperature and reduced pressure to remove the generated phenol out of the system.

[0003]

In the melt polycondensation method, the reaction mixture moves between reactors in a molten state at a high temperature or is discharged from the reactor. During this transfer between reactors or during discharge from the reactor,
The reaction mixture in a molten state may be exposed to a high temperature and may be colored or generate foreign matters, thereby impairing excellent properties such as transparency of the aromatic polycarbonate. In particular,
In an aromatic polycarbonate used for optical applications such as a compact disc, coloring and foreign matter are not preferable in terms of product quality. Here, in the present specification,
"Reaction mixture" refers to a mixture mainly containing an aromatic dihydroxy compound and an aromatic carbonate diester in the presence of a transesterification catalyst or the like comprising a nitrogen-containing basic compound and an alkali metal compound and / or an alkaline earth metal compound. In the step of obtaining an aromatic polycarbonate by a melt polycondensation reaction, it refers to a mixture that has started or is undergoing the polycondensation reaction. For example, in the state of "prepolymer", and further advanced is in the state of "polymer" in general chemical terms.

[0004]

SUMMARY OF THE INVENTION The present invention is as follows. 1. When a mixture mainly containing an aromatic dihydroxy compound and a carbonic acid diester is continuously melt-polycondensed in the presence of a catalyst to produce an aromatic polycarbonate, the flow rate of the reaction mixture in a pipe through which the molten reaction mixture passes Is 0.5 cm / sec or more.

[0005] 2. When a mixture mainly containing an aromatic dihydroxy compound and a carbonic acid diester is continuously melt-polycondensed in the presence of a catalyst to produce an aromatic polycarbonate, the flow rate of the reaction mixture in a pipe through which the molten reaction mixture passes Is 2 cm / sec or more.

[0006] 3. 3. The method for producing an aromatic polycarbonate according to the above 1 or 2, wherein the viscosity average molecular weight of the reaction mixture in the pipe through which the molten reaction mixture passes is 1000 or more.

[0007] 4. 3. The method for producing an aromatic polycarbonate according to any one of the above items 1 to 3, wherein the total of the average residence times of the reaction mixture in a pipe through which the molten reaction mixture passes is 3 hours or less.

[0008] 5. The method for producing an aromatic polycarbonate according to any one of the above 1 to 4, wherein the temperature of the wall surface of the pipe through which the molten reaction mixture passes is higher than the temperature of the reaction mixture in the pipe.

6. 6. The method for producing an aromatic polycarbonate according to any one of the above items 1 to 5, wherein a pipe through which the molten reaction mixture passes is a cold-drawn stainless steel pipe.

[0010] 7. 6. The method for producing an aromatic polycarbonate according to any one of the above 1 to 5, wherein the pipe through which the molten reaction mixture passes is a stainless steel pipe whose inner surface is buffed.

The present invention relates to a process for producing an aromatic polycarbonate by continuously melt-polycondensing a mixture mainly containing an aromatic dihydroxy compound and a carbonic acid diester in the presence of a catalyst. It is characterized in that the heat history in the pipe passing through the pipe while moving between the pipes or being discharged from the reactor is reduced, and the flow of the reaction mixture in the pipe is smooth.

According to the method for producing an aromatic polycarbonate according to the present invention, the flow rate of the reaction mixture in the pipe through which the molten reaction mixture passes is high, the heat history in the pipe is small, and the reaction mixture flows in the pipe. Since it flows smoothly, there is no quality deterioration in the piping at the time of production, and it is possible to produce an aromatic polycarbonate excellent in hue and free of foreign matter.

Hereinafter, the method for producing an aromatic polycarbonate according to the present invention will be specifically described. As the aromatic dihydroxy compound used in the present invention, for example,
Bis (4-hydroxyphenyl) methane, 2,2-bis (4-hydroxyphenyl) propane, 2,2-bis (4-hydroxy-3-methylphenyl) propane,
4,4-bis (4-hydroxyphenyl) heptane,
2,2-bis (4-hydroxy-3,5-dichlorophenyl) propane, 2,2-bis (4-hydroxy-3,
5-dibromophenyl) propane, bis (4-hydroxyphenyl) oxide, bis (3,5-dichloro-4)
-Hydroxyphenyl) oxide, p, p'-dihydroxydiphenyl, 3,3'-dichloro-4,4'-dihydroxydiphenyl, bis (hydroxyphenyl) sulfone, resorcinol, hydroquinone, 1,4-dihydroxy-2,5- Examples thereof include dichlorobenzene, 1,4-dihydroxy-3-methylbenzene, bis (4-hydroxyphenyl) sulfide, and bis (4-hydroxyphenyl) sulfoxide, and particularly, 2,2-bis (4-hydroxyphenyl) propane. Is preferred.

Examples of the carbonic acid diester used in the present invention include diphenyl carbonate, ditolyl carbonate, bis (chlorophenyl) carbonate, m-cresyl carbonate, dinaphthyl carbonate, bis (diphenyl) carbonate, dimethyl carbonate, and the like.
Diethyl carbonate, dibutyl carbonate, dicyclohexyl carbonate and the like are used. Of these, diphenyl carbonate is particularly preferred.

The catalyst used in the present invention is not particularly limited. Examples of the alkali metal compound include hydroxides, hydrogen carbonates, carbonates, acetates, nitrates, nitrites, sulfites and cyanates of alkali metals. Thiocyanate, stearate, borohydride, benzoate, hydrogen phosphate, bisphenol, phenol salt and the like.

Specific examples include sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium hydrogen carbonate, potassium hydrogen carbonate, lithium hydrogen carbonate, sodium carbonate,
Potassium carbonate, lithium carbonate, sodium acetate, potassium acetate, lithium acetate, sodium nitrate, potassium nitrate, lithium nitrate, sodium nitrite, potassium nitrite, lithium nitrite, sodium sulfite, potassium sulfite, lithium sulfite, sodium cyanate, potassium cyanate , Lithium cyanate, sodium thiocyanate,
Potassium thiocyanate, lithium thiocyanate, sodium stearate, potassium stearate, lithium stearate, sodium borohydride, potassium borohydride, lithium borohydride, sodium phenylated borate, sodium benzoate, potassium benzoate, benzoate Lithium acid, disodium hydrogenphosphate, dipotassium hydrogenphosphate, dilithium hydrogenphosphate, disodium salt, dipotassium salt, dilithium salt of bisphenol A, phenol sodium salt, potassium salt, lithium salt, etc. A sodium salt of an aromatic dihydroxy compound, for example, a disodium salt of bisphenol A or a sodium salt of an aromatic monohydroxy compound, for example, a sodium salt of phenol is preferably used.

The alkali metal compound used as the catalyst is used in such a ratio that the alkali metal element in the catalyst is 1 × 10 ⁻³ to 1 × 10 ⁻⁸ equivalent per mole of the aromatic dihydroxy compound. It is preferably used in a ratio of 5 × 10 ⁻⁶ to 1 × 10 ⁻⁸ equivalent, more preferably 5 × 10 ⁻⁶ to 1 × 10 ⁻⁷ equivalent. If the amount is outside the above range, the properties of the obtained polycarbonate are adversely affected, and the transesterification reaction does not sufficiently proceed to obtain a high-molecular-weight polycarbonate, which is not preferable.

The catalyst used in the present invention includes a nitrogen-containing basic compound. Such as tetramethylammonium hydroxide (Me ₄ NOH), tetraethylammonium hydroxide (Et ₄ NOH), tetrabutylammonium hydroxide (Bu ₄ NOH), benzyltrimethylammonium hydroxide (φ-CH ₂ (M
e) ₃ NOH), alkyl such as hexadecyltrimethylammonium hydroxide, aryl, ammonium hydroxide oxides having an alkyl aryl group, triethylamine, tributylamine, dimethylbenzylamine, tertiary amines such as hexadecyl dimethylamine, or Tetramethylammonium borohydride (Me ₄ NBH ₄ ), tetrabutylammonium borohydride (Bu ₄ NBH ₄ ), tetrabutylammonium tetraphenylborate (Me ₄ NBPh ₄ ), tetrabutylammonium tetraphenylborate (Bu ₄ N)
And basic salts such as BPh ₄ ).
Tetramethylammonium hydroxide (Me ₄ NO
H) is most preferably used.

In the present invention, if desired, (a) an alkali metal salt of an ate complex of an element of Group 14 of the periodic table or (b) an oxoacid of an element of Group 14 of the periodic table Can be used. Here, the elements of Group 14 of the periodic table refer to silicon, germanium, and tin.

The use of these alkali metal compounds as a polycondensation reaction catalyst has the advantage that the polycondensation reaction can be promptly and sufficiently promoted. Further, undesirable side reactions such as a branching reaction generated during the polycondensation reaction can be suppressed to a low level.

(A) As an alkali metal salt of an ate complex of a group 14 element of the periodic table, those described in JP-A-7-268091 are mentioned. Specifically, a compound of germanium (Ge); NaGe (OMe) ₅ , NaGe
(OEt) ₃ , NaGe (OPr) ₅ , NaGe (OB
u) ₅ , NaGe (OPh) ₅ , LiGe (OMe) ₅ ,
LiGe (OBu) ₅ and LiGe (OPh) ₅ can be given.

As a compound of tin (Sn), NaSn
(OMe) ₃ , NaSn (OMe) ₂ (OEt), NaS
n (OPr) ₃ , NaSn (On-C ₆ H ₁₃ ) ₃ , Na
Sn (OMe) ₅ , NaSn (OEt) ₅ , NaSn (O
_{Bu) 5, NaSn (O-} n-C 12 H 25) 5, NaSn
(OEt), NaSn (OPh) ₅ , NaSnBu ₂ (O
Me) ₃ can be mentioned.

(B) The alkali metal salt of an oxo acid of Group 14 element of the periodic table includes, for example, silicic acid (silicic acid).
Cic acid), stannic acid (sta)
alkali metal salt of germanic acid, germanium (II) acid, germanic acid (germanic acid), germanic acid (germanic acid)
The alkali metal salts of acid) can be mentioned as preferred.

The alkali metal salt of silicic acid is, for example, an acidic or neutral alkali metal salt of monosilicic acid (monosilicic acid) or a condensate thereof, and examples thereof include monosodium orthosilicate, disodium orthosilicate, and orthosilicate. Trisodium and tetrasodium orthosilicate can be mentioned.

The alkali metal salt of stannic acid is, for example, an acidic or neutral alkali metal salt of monostannic acid or a condensate thereof, and examples thereof include disodium monostannate (Na ₂ SnO ₃ · C).
_{H 2 O, x = 0~5)} , mention may be made of Monosuzu acid tetrasodium salt (Na ₄ SnO _4).

Germanium (II) acid (germanou)
The alkali metal salt of s acid) is, for example, an acidic or neutral alkali metal salt of monogermanic acid or a condensate thereof, and examples thereof include monosodium germanate (NaHGeO ₂ ).

Germanic (IV) acid (germanic)
The alkali metal salt of acid (acid) is, for example, an acidic or neutral alkali metal salt of monogermanic acid (IV) or a condensate thereof, and examples thereof include monogermanic acid orthogermanate (LiH ₃ GeO ₄ ) orthogermanate. Sodium salt, tetrasodium orthogermanate, disodium digermanate (Na ₂ G
e ₂ O ₅ ), disodium tetragermanate (Na
₂ Ge ₄ O ₉ ) and disodium pentagermanate (Na ₂ Ge ₅ O ₁₁ ).

The above-mentioned polycondensation reaction catalyst is preferably used in such a ratio that the alkali metal element in the catalyst is 1 × 10 ⁻³ to 1 × 10 ⁻⁸ equivalent per mole of the aromatic dihydroxy compound. A more desirable ratio is 5 × 10 ^{−6 with} respect to the same standard.
It is a ratio which becomes １1 × 10 ^-8 equivalents, and a more preferable ratio is a ratio which becomes 5 × 10 ^-6 -1 × 10 ^-7 equivalents.

In the polycondensation reaction of the present invention, if necessary, at least one member selected from the group consisting of oxo acids of Group 14 elements of the periodic table and oxides of the same, together with the above catalyst.
Various co-catalysts can be co-present.

By using these co-catalysts in a specific ratio, the terminal blocking reaction and the polycondensation reaction rate are not impaired, the branching reaction which is liable to be generated during the polycondensation reaction, or the foreign matter in the apparatus at the time of molding is performed. Undesirable side reactions such as generation and burning can be more effectively suppressed.

The oxo acids of Group 14 elements of the periodic table include, for example, silicic acid, stannic acid and germanic acid.

The oxides of Group 14 elements of the periodic table include:
Mention may be made of silicon monoxide, silicon dioxide, tin monoxide, tin dioxide, germanium monoxide, germanium dioxide and condensates thereof.

The co-catalyst should be present in a proportion such that the metal element of Group 14 of the periodic table in the co-catalyst is not more than 50 mol (atoms) per 1 mol (atom) of the alkali metal element in the polycondensation reaction catalyst. preferable. If the co-catalyst is used in a proportion of more than 50 moles (atoms) of the same metal element, the rate of polycondensation reaction is undesirably reduced.

The cocatalyst is present in such a proportion that the metal element of Group 14 of the periodic table of the cocatalyst is 0.1 to 30 mol (atoms) per 1 mol (atom) of the alkali metal element of the polycondensation reaction catalyst. Is more preferred.

These catalyst systems have an advantage that the polycondensation reaction and the terminal blocking reaction can be promptly and sufficiently advanced by being used for the polycondensation reaction. Further, undesirable side reactions such as a branching reaction generated in the polycondensation reaction system can be suppressed to a low level.

[0036] Melt polymerization is a method for producing a polycarbonate which does not use phosgene or a halogenated solvent and has low environmental problems, and is expected to have an advantage in cost. In particular, it has a problem that it is inferior to polycarbonate obtained by the interfacial polymerization method in terms of hue and gel, and various proposals have been made to solve this problem. However, no satisfactory method has yet been found.

In view of this situation, the present inventors have studied the equipment to be used, and as a result, have obtained a pipe which pays attention to the contact between the reaction mixture and the apparatus and occupies a large proportion of the contact area per volume. The present invention was found to have a great effect on the quality of polycarbonate and reached the present invention.

According to the study of the present inventors, there have been no proposals focusing on piping, and proposals in which the surface roughness is specified to be 5 μm or less have been known, but this alone is not sufficient. It turned out that a great effect can be obtained by considering several factors comprehensively. Although the cause is not clear, on the other hand, the reaction mixture usually has a high melt viscosity and is considered to be moving in a laminar flow state in the pipe. In this state, the film (the reaction mixture in contact with the inner wall of the pipe) is considered to be moving. (Where the flow rate is very slow) is considered to constitute a pseudo dead space, whereas on the other hand, unlike other condensation-polymerized polymers such as polyethylene terephthalate, polycarbonate is completely free of other factors such as oxygen. , By heating for a long time, it has a characteristic that it is itself branched, forming a crosslinked structure and gelling,
It is considered that these two characteristics greatly affect the polymer quality. The present invention is configured by eliminating the pseudo dead space as much as possible.

In the method for producing an aromatic polycarbonate according to the present invention, the higher the flow rate of the reaction mixture in the pipe through which the molten reaction mixture passes, the less the deterioration of the quality of the reaction mixture in the pipe and the better the hue. And an aromatic polycarbonate free of foreign matter can be produced. The flow rate of the molten reaction mixture in the pipe is preferably 0.5 cm / sec or more, particularly preferably 2 cm / sec or more. Here, the pipe means a pipe connecting the reactors through which the molten reaction mixture passes and a pipe discharged from the reactor.

In the method for producing an aromatic polycarbonate according to the present invention, the reaction mixture preferably has a viscosity average molecular weight of 1,000 or more. If the viscosity-average molecular weight is smaller than this value, the effect becomes smaller, probably because pseudo dead space is less generated.

In order to reduce the heat history of the reaction mixture in the piping, it is important to shorten the average residence time of the reaction mixture in the piping. In the method for producing an aromatic polycarbonate according to the present invention, the average residence time of the reaction mixture in the pipe is preferably within 3 hours, more preferably within 1 hour.

In the method for producing an aromatic polycarbonate according to the present invention, in order to make the flow of the reaction mixture in the pipe smooth and to prevent the flow rate of the reaction mixture from decreasing on the pipe wall surface, the temperature of the wall surface of the pipe through which the reaction mixture passes is controlled by: It is preferable that the temperature be higher than the temperature of the reaction mixture passing therethrough and the melt viscosity of the reaction mixture on the pipe wall surface be lowered. The wall surface temperature of the pipe is preferably 2 ° C. to 50 ° C. higher than the temperature of the reaction mixture in the pipe, more preferably 5 ° C. to 20 ° C.

In order to make the flow of the reaction mixture in the pipe between the reactors or in the pipe discharged from the reactor smooth, the processing method and material of the pipe are also important. In the method for producing an aromatic polycarbonate according to the present invention,
The pipe through which the molten reaction mixture passes is preferably a cold drawn stainless steel pipe. As the stainless steel material, for example, SUS304, SUS31
6, SUS316L and the like.

In the method for producing an aromatic polycarbonate according to the present invention, the inner surface of the pipe through which the molten reaction mixture passes is made as smooth as possible so that the flow of the reaction mixture is smoothed by buffing. Is preferred. The buff finish is preferably # 100 or more, more preferably # 400 or more.

Incidentally, a catalyst deactivator can be added to the polycarbonate obtained in the present invention.

As the catalyst deactivator used in the present invention, known catalyst deactivators are effectively used, and among these, ammonium salts and phosphonium salts of sulfonic acid are preferable.
Further, the above salts of dodecylbenzenesulfonic acid such as tetrabutylphosphonium dodecylbenzenesulfonate and the above salts of paratoluenesulfonic acid such as tetrabutylammonium p-toluenesulfonate are preferred. Also, methyl benzenesulfonate as an ester of sulfonic acid,
Ethyl benzenesulfonate, butyl benzenesulfonate, octyl benzenesulfonate, phenyl benzenesulfonate, methyl paratoluenesulfonate, ethyl paratoluenesulfonate, butyl paratoluenesulfonate,
Octyl p-toluenesulfonate, phenyl p-toluenesulfonate and the like are preferably used, and among them, tetrabutylphosphonium dodecylbenzenesulfonate is most preferably used.

The amount of the catalyst deactivator used is 0.5 to 50 mol, preferably 0.5 to 50 mol, per 1 mol of the polymerization catalyst selected from alkali metal compounds and / or alkaline earth metal compounds. It can be used at a ratio of 10 mol, more preferably at a ratio of 0.8 to 5 mol.

These catalyst deactivators are added directly to the molten polycarbonate and kneaded, or dissolved or dispersed in an appropriate solvent. There is no particular limitation on the equipment used to carry out such an operation, but for example, a twin-screw ruder is preferable, and a vented twin-screw ruder is particularly preferable when the catalyst deactivator is dissolved or dispersed in a solvent. used.

In the present invention, additives can be added to the polycarbonate as long as the object of the present invention is not impaired. This additive is preferably added to the molten polycarbonate similarly to the catalyst deactivator. Examples of such an additive include a heat stabilizer, an epoxy compound, an ultraviolet absorber, a release agent, a colorant, Slip agents, anti-blocking agents, lubricants, organic fillers, inorganic fillers and the like can be mentioned.

Of these, heat stabilizers, ultraviolet absorbers, release agents, coloring agents and the like are particularly generally used, and these can be used in combination of two or more.

The heat stabilizer used in the present invention includes:
For example, a phosphorus compound, a phenol-based stabilizer, an organic thioether-based stabilizer, a hindered amine-based stabilizer and the like can be mentioned.

As the ultraviolet absorber, a general ultraviolet absorber is used, for example, a salicylic acid ultraviolet absorber, a benzophenone ultraviolet absorber, a benzotriazole ultraviolet absorber, a cyanoacrylate ultraviolet absorber and the like. Can be mentioned.

As the release agent, generally known release agents can be used, for example, hydrocarbon release agents such as paraffins, fatty acid release agents such as stearic acid, and stearamide. Release agents such as fatty acid amides, alcohol release agents such as stearyl alcohol and pentaerythritol, fatty acid ester release agents such as glycerin monostearate and pentaerythritol stearate, and silicone release agents such as silicone oil. And the like.

As the colorant, organic or inorganic pigments or dyes can be used.

The method of adding these additives is not particularly limited. For example, the additives may be added directly to the polycarbonate, or a master pellet may be prepared and added.

[0056]

According to the present invention, the flow rate of the reaction mixture in the pipe through which the molten reaction mixture passes is high, the heat history in the pipe is small, and the reaction mixture flows smoothly in the pipe. It is possible to produce an aromatic polycarbonate which is excellent in hue and free of foreign matter without quality deterioration in piping at the time.

[0057]

Embodiments will be described below with reference to embodiments. The percentages and parts in the examples are% by weight and parts by weight unless otherwise specified. The physical properties of the reaction mixture and the polycarbonate obtained in the following examples, the average flow velocity of the reaction mixture in the pipe, and the average residence time in the pipe were measured as follows.

[Intrinsic viscosity and viscosity average molecular weight] 0.7 g
/ Dl methylene chloride solution was measured for intrinsic viscosity using an Ubbelohde viscometer, and the viscosity average molecular weight was determined by the following equation. [Η] = 1.23 × 10 ⁻⁴ M ^0.83

[Color (b value)] Lab of polycarbonate pellets (short diameter × long diameter × length (mm) = 2.5 × 3.3 × 3.0)
The value was measured by a reflection method using ND-1001DP manufactured by Nippon Denshoku Industries Co., Ltd., and the b value was used as a scale of yellowness.

[Average Flow Rate of Reaction Mixture in Pipe] The flow rate of the reaction mixture in the pipe was divided by the inner diameter of the pipe.

[Average residence time of the reaction mixture in the pipe] The volume was determined by dividing the volume in the pipe by the flow rate of the reaction mixture. The sum of the average residence times is the sum of the values for each pipe.

[Foreign material amount] Polycarbonate pellet 1K
g was dissolved in 5 L of methylene chloride, and then filtered using a filter having an opening of 30 μm, and the number of foreign substances collected on the filter was counted.

Example 1 A melt polycondensation of an aromatic polycarbonate was carried out using the following reaction equipment.
A raw material preparation tank in which an aromatic dihydroxy compound and a carbonic acid diester are respectively metered and heated and melted, a raw material prepared from the raw material preparation tank, and a raw material capable of continuously and quantitatively supplying the raw material to the first polymerization first tank. A raw material supply tank equipped with a pump, a catalyst preparation tank capable of metering in the polymerization catalyst and phenol that dissolves the catalyst, a catalyst solution prepared from the catalyst preparation tank is received, and the catalyst solution can be supplied to the initial polymerization first tank in a constant amount. The melt polycondensation reaction was continuously performed using a polymerization apparatus having a catalyst supply tank equipped with a catalyst pump as an incidental facility.

The material for the initial polymerization tank is SUS316L.
Two vertical stirring tanks were connected in series, each having an internal coil and a jacket.

These two initial polymerization tanks (first tank, second tank)
Rectification column provided with a reflux mechanism for separating a monohydroxy compound generated in the reaction and a carbonic acid diester as a raw material.

The reaction mixture in the first tank was a cold drawn SUS having an inner diameter of 20 mm connecting the first and second tanks.
It was continuously supplied to the second tank by a gear pump installed in a 316L pipe.

The length of the pipe connecting the first tank and the second tank was 4 m excluding the gear pump. The pipe connecting the first tank and the second tank was provided with a jacket so that heating and cooling could be performed from the outside, and the inner surface of the pipe used was finished with a buff # 400.

The amount of liquid sent from the first tank was controlled by interlocking the indicated value of the level meter of the first tank and the rotation speed of the gear pump installed on the outlet pipe of the first tank.

The reaction mixture in the second tank is continuously supplied to the late polymerization tank by a gear pump installed in a cold drawn SUS316L pipe having an inner diameter of 20 mm connecting the second tank and the late polymerization tank. did.

The length of the pipe connecting the second tank and the late polymerization tank was 4 m excluding the gear pump part. The piping connecting the second tank and the late polymerization tank is provided with a jacket so that it can be heated and cooled from the outside.
The surface finished with 400 was used.

The amount of liquid sent from the second tank was controlled in conjunction with the indicated value of the level meter of the second tank and the rotation speed of the gear pump installed on the outlet pipe of the second tank.

The late polymerization tank is a uniaxial horizontal stirring tank,
No rectification tower is provided, and a jacket is attached to the whole.

The amount of liquid sent from the late polymerization tank was determined by the level indicated by the level meter of the late polymerization tank and the cold drawn SUS3 having an inner diameter of 20 mm connecting the late polymerization tank and the twin screw extruder.
The rotation speed of the gear pump installed in the 16L pipe was controlled in conjunction.

The length of the pipe connecting the late polymerization tank and the twin screw extruder was 4 m. A pipe connecting the late polymerization tank and the twin-screw extruder was provided with a jacket so that heating and cooling could be performed from the outside, and the inside of the pipe was used whose surface was finished with a buff # 400.

Reaction mixture (polymer) leaving the late polymerization tank
After passing through a twin-screw extruder, it was extruded from a die, formed into a strand in a cooling bath, and then pelletized by a cutter.

The operating conditions for melt polycondensation were as follows. Bisphenol A was used as the aromatic dihydroxy compound, and diphenyl carbonate was used as the carbonic acid diester. 500 kg of diphenyl carbonate (2.33 K
mol) was charged into a raw material melting tank and melted. Then, 527.6 kg (2.31 Kmol) of bisphenol A was charged and stirred and melted. The raw material mixture thus prepared was transferred to a raw material supply tank.

As a polymerization catalyst, a disodium salt of bisphenol A was used. The catalyst, in the catalyst preparation tank,
Phenol / water = so that the catalyst concentration becomes 30 ppm
It was dissolved in a 90/10 weight ratio mixture. The catalyst solution thus prepared was transferred to a catalyst supply tank.

The feed rate of the raw material to the first tank was 50 kg / hr,
The flow rates of the raw material supply pump and the catalyst solution supply pump were adjusted so that the catalyst solution supply amount was 0.29 kg / hr,
Continuous melt polycondensation was performed.

The operation conditions of each polymerization tank are as follows.
30 ° C., degree of vacuum 100 Torr, the second tank has an internal temperature of 260 ° C.,
The degree of vacuum was 15 Torr, the temperature of the heating medium in the outer polymerization tank in the outer jacket was 270 ° C., and the degree of vacuum was 0.5 Torr.

In the pipe through which the molten reaction mixture passes, the temperature of the heating medium in the pipe jacket was set to be higher than the temperature of the reaction mixture in the pipe. The temperature difference was as shown in Table 1 for each pipe.

A continuous operation was carried out for 600 hours under the above-mentioned apparatus and operating conditions, and after 200 hours, 400 hours, and 600 hours, the reaction mixture was passed through each outlet of the first tank, the second tank, the late polymerization tank, and the twin-screw extruder. Was measured, and sampling was performed.

Table 2 shows the evaluation results of the samples collected after 200 hours, Table 3 shows the evaluation results of the samples collected after 400 hours, and Table 4 shows the evaluation results of the samples collected after 600 hours. Tables 2 to 4 also show the average flow rate and average residence time of the reaction mixture in each pipe in this example.

Example 2 Using the same apparatus as in Example 1, the feed rate of the raw material to the first tank was 12.5 kg / hr.
The flow rates of the raw material supply pump and the catalyst solution supply pump were adjusted so that the supply amount of the catalyst solution was 0.075 kg / hr, and continuous melt polycondensation was performed. The operating conditions of each polymerization tank were the same as in Example 1, and the continuous operation was performed for 600 hours.
After the lapse of 00 hours, 400 hours, and 600 hours, the flow rate of the reaction mixture was measured at each outlet of the first tank, the second tank, the late polymerization tank, and the twin-screw extruder, and sampling was performed.

In the piping through which the molten reaction mixture passes, the temperature of the reaction mixture in the piping and the temperature of the heating medium in the piping jacket were set the same as in Example 1.

Table 2 shows the evaluation results of the samples collected after 200 hours, Table 3 shows the evaluation results of the samples collected after 400 hours, and Table 4 shows the evaluation results of the samples collected after 600 hours. Tables 2 to 4 also show the average flow rate and average residence time of the reaction mixture in each pipe in this example.

[Example 3] In the apparatus of Example 1, the pipe length between the first tank and the second tank was changed from 4 m to 12 m, and the pipe length between the second tank and the late polymerization tank was changed. 4m to 12
m, and the pipe length between the late polymerization tank and the twin-screw extruder was changed from 4 m to 12 m. The supply amount of the raw material to the first tank was 12.5 kg / hr, and the supply amount of the catalyst solution was 0.07 kg / hr.
The flow rates of the raw material supply pump and the catalyst solution supply pump were adjusted to 5 kg / hr, and the continuous operation was performed for 600 hours. 200 hours, 400 hours, 600 hours of continuous operation
At the elapse of time, the flow rate was measured at each outlet of the first tank, the second tank, the late polymerization tank, and the twin-screw extruder, and sampling was performed.

In the piping through which the molten reaction mixture passes, the temperature of the reaction mixture in the piping and the temperature of the heating medium in the piping jacket were set the same as in Example 1.

Table 2 shows the evaluation results of the samples collected after 200 hours, Table 3 shows the evaluation results of the samples collected after 400 hours, and Table 4 shows the evaluation results of the samples collected after 600 hours. Tables 2 to 4 also show the average flow rate and average residence time of the reaction mixture in each pipe in this example.

[Example 4] Same as Example 3 except that the inner surface of the piping between the polymerization tanks and between the late polymerization tank and the twin-screw extruder was buffed with # 100 in the apparatus of Example 3. A continuous operation for 600 hours was performed under the apparatus and operating conditions. When the continuous operation was performed for 200 hours, 400 hours, and 600 hours, the flow rate was measured at each outlet of the first tank, the second tank, the late polymerization tank, and the twin-screw extruder, and sampling was performed.

In the piping through which the molten reaction mixture passed, the temperature of the reaction mixture in the piping and the temperature of the heating medium in the piping jacket were set the same as in Example 1.

Table 2 shows the evaluation results of the samples collected after 200 hours, Table 3 shows the evaluation results of the samples collected after 400 hours, and Table 4 shows the evaluation results of the samples collected after 600 hours. Tables 2 to 4 also show the average flow rate and average residence time of the reaction mixture in each pipe in this example.

[Example 5] In the apparatus of Example 4, the materials of the pipes between the polymerization tanks and between the late polymerization tank and the twin-screw extruder were all made of SUS30 having been subjected to cold drawing.
Except for changing to 4, the same device as in Example 3 and operating conditions of 6
A continuous operation of 00 hours was performed. 200 hours, 400 hours, 600 hours after the first tank, the second tank,
The flow rate was measured at each outlet of the late polymerization tank and the twin-screw extruder, and sampling was performed.

In the pipe through which the molten reaction mixture passes, the temperature of the reaction mixture in the pipe and the temperature of the heating medium in the pipe jacket were set to be the same as those in Example 1.

Table 2 shows the evaluation results of the samples collected after 200 hours, Table 3 shows the evaluation results of the samples collected after 400 hours, and Table 4 shows the evaluation results of the samples collected after 600 hours. Tables 2 to 4 also show the average flow rate and average residence time of the reaction mixture in each pipe in this example.

Comparative Example 1 In the apparatus of Example 1, the inner diameter of the pipe between each polymerization tank and between the late polymerization tank and the twin-screw extruder was changed from 20 mm to 40 mm, and the pipe length was changed from 4 m. The same equipment as in Example 1 was used, except that the raw material supply amount to the first tank was changed to 12.5 kg / h, except that it was changed to 2 m.
r, the flow rates of the raw material supply pump and the catalyst solution supply pump were adjusted so that the supply amount of the catalyst solution was 0.075 Kg / hr, and continuous melt polycondensation was performed. The operating conditions of each polymerization tank were the same as in Example 1, and the continuous operation was performed for 600 hours.
200 hours, 400 hours, the first tank after 600 hours,
The flow rate was measured at each outlet of the second tank, the late polymerization tank, and the twin-screw extruder, and sampling was performed.

In the pipe through which the molten reaction mixture passed, the temperature of the reaction mixture in the pipe and the temperature of the heating medium in the pipe jacket were set the same as in Example 1.

Table 2 shows the evaluation results of the samples collected after 200 hours, Table 3 shows the evaluation results of the samples collected after 400 hours, and Table 4 shows the evaluation results of the samples collected after 600 hours. Tables 2 to 4 also show the average flow rate and average residence time of the reaction mixture in each pipe in this example.

Comparative Example 2 In the apparatus of Example 1, the inner diameter of the pipe between each polymerization tank and between the latter polymerization tank and the twin-screw extruder was changed from 20 mm to 50 mm, and the pipe length was changed from 4 m. The same apparatus as in Example 1 was used except that the length was changed to 25 m, and continuous operation was performed for 600 hours under the same operating conditions as in Example 1. The first tank, the second tank, and the late polymerization tank when the continuous operation is performed for 200 hours, 400 hours, and 600 hours,
The flow rate was measured at each outlet of the twin screw extruder, and sampling was performed.

In the pipe through which the molten reaction mixture passed, the temperature of the reaction mixture in the pipe and the temperature of the heating medium in the pipe jacket were set the same as in Example 1.

Table 2 shows the evaluation results of the samples collected after 200 hours, Table 3 shows the evaluation results of the samples collected after 400 hours, and Table 4 shows the evaluation results of the samples collected after 600 hours. Tables 2 to 4 also show the average flow rate and average residence time of the reaction mixture in each pipe in this example.

[0101]

[Table 1]

[0102]

[Table 2]

[0103]

[Table 3]

[0104]

[Table 4]

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Toru Sawaki 2-1 Hinodecho, Iwakuni-shi, Yamaguchi Prefecture Teijin Co., Ltd. Inside the Iwakuni Research Center (72) Inventor Katsushi Sasaki 2-1 Hinodecho, Iwakuni-shi, Yamaguchi Prefecture Teijin Shares F-term in the Iwakuni Research Center of the Company (reference) JC731 JF021 JF031 JF041 KC01 KD01 KD17 KE05 LA08 LA10 LA14 LB04 LB10

Claims (7)

[Claims] 1. A process for melt-polycondensing a mixture mainly containing an aromatic dihydroxy compound and a carbonic acid diester in the presence of a catalyst to produce an aromatic polycarbonate in a pipe through which a molten reaction mixture passes. Wherein the flow rate of the reaction mixture is 0.5 cm / sec or more. 2. A mixture mainly containing an aromatic dihydroxy compound and a carbonic acid diester is continuously melt-polycondensed in the presence of a catalyst to produce an aromatic polycarbonate. In a pipe through which a molten reaction mixture passes, 2. The method for producing an aromatic polycarbonate according to claim 1, wherein the flow rate of the reaction mixture is 2 cm / sec or more. 3. The method for producing an aromatic polycarbonate according to claim 1, wherein the viscosity average molecular weight of the reaction mixture in the pipe through which the molten reaction mixture passes is 1000 or more. 4. The method for producing an aromatic polycarbonate according to claim 1, wherein the total of the average residence time of the reaction mixture in the pipe through which the molten reaction mixture passes is 3 hours or less. 5. The process for producing an aromatic polycarbonate according to claim 1, wherein the temperature of the wall surface of the pipe through which the molten reaction mixture passes is higher than the temperature of the reaction mixture in the pipe. 6. The method for producing an aromatic polycarbonate according to claim 1, wherein the pipe through which the molten reaction mixture passes is a cold drawn stainless steel pipe. 7. The method for producing an aromatic polycarbonate according to claim 1, wherein the pipe through which the molten reaction mixture passes is a stainless steel pipe whose inner surface is buffed.