JP5233084B2 - Polycarbonate resin production apparatus and polycarbonate resin production method - Google Patents

Description

  The present invention relates to an apparatus for manufacturing a polycarbonate resin, and more particularly to an apparatus for manufacturing a polycarbonate resin with reduced generation of foreign matter.

  Polycarbonate resins are widely used as engineering plastics in many fields, taking advantage of their excellent heat resistance, impact resistance, transparency, and dimensional stability. As an industrial production method of this polycarbonate resin, a method of reacting an aromatic dihydroxy compound and phosgene at the interface by introducing phosgene in an alkali aqueous solution of an aromatic dihydroxy compound and a halogen-based organic solvent (interface) And a transesterification method (melting method) in which an aromatic dihydroxy compound and a carbonic acid diester are reacted in a molten state.

  When a polycarbonate resin is produced by such a transesterification reaction (melting method), generally, a carbonic acid diester and an aromatic dihydroxy compound as raw materials are dissolved, and a transesterification catalyst is added thereto, followed by polymerization under reduced pressure. Heat and stir in the bath. The polycondensation reaction by transesterification proceeds while distilling out by-products such as aromatic monohydroxy compounds and / or aliphatic monohydroxy compounds, and a polycarbonate resin is produced (see Patent Document 1).

Japanese Patent Laying-Open No. 2003-192882 (see FIG. 1)

By the way, as described above, when a polycarbonate resin is continuously produced by transesterification (melting method), the raw material melt is usually supplied to a plurality of polymerization tanks controlled at high temperature and reduced pressure, and the polymerization reaction In general, a method of sequentially increasing the degree of polymerization while continuously supplying the liquid to a subsequent polymerization tank is performed.
However, for example, in the case of a method in which the raw material melt or polymerization reaction liquid is directly introduced into the polymerization tank from the supply port provided on the top plate at the top of the polymerization tank, the amount of foreign matter in the final product tends to increase. . This will be described with reference to the drawings.

FIG. 3 is a view for explaining a conventional polycarbonate resin production apparatus. In FIG. 3, a mixed liquid of raw material melt and catalyst is supplied to a vertical polymerization tank 22e equipped with a stirring blade 20e through a supply pipe 18e by a supply pump 17e, and a predetermined average is maintained while maintaining a liquid level 21e. The transesterification reaction is performed during the residence time, and the polymerization reaction liquid is discharged from the bottom of the vertical polymerization tank 22e to the next step through the delivery pipe 23e. The inside of the vertical polymerization tank 22e is kept in a reduced pressure state by a predetermined pressure reducing device (not shown). Further, by-product phenol and the like are distilled from the by-product distillation pipe 19e.

(Figure 3 was used as an explanation of the prior art, so e was added to distinguish it from Figure 2 (the present invention).)

As shown in FIG. 3, when a raw material melt or a polymerization reaction liquid is directly introduced into a vertical polymerization tank 22e maintained in a reduced pressure state from a supply port provided on the top plate of the vertical polymerization tank 22e. In some cases, the raw material melt or the polymerization reaction liquid scatters at the outlet of the supply port and adheres to the top plate of the vertical polymerization tank 22e, the stirring blade 20e, or the like. In addition, the raw material melt or the like scattered on the side plate may hang down along the wall surface, which may cause the raw material mixture ratio to fluctuate.
Furthermore, if such deposits grow, they tend to be crystallized foreign matters or burnt foreign matters, and if they fall into the polymerization reaction solution, the amount of foreign matters in the final product increases, so a solution is required. It is said that.

This invention is made in order to solve the problem at the time of manufacturing a polycarbonate resin continuously using the manufacturing apparatus which connected such a some polymerization tank.
That is, an object of the present invention is to provide an apparatus for producing a polycarbonate resin that makes it difficult for deposits to form on the top plate or the like of a polymerization tank and reduces the generation of foreign matter.
Another object of the present invention is to provide a method for producing a polycarbonate resin in which the generation of foreign matter is reduced.

As a result of intensive studies to solve the above problems, the present inventors attached an insertion tube having an opening in the gas phase portion in the polymerization tank to the supply port provided in the top plate at the top of the polymerization tank. Then, when a raw material melt or the like was introduced into the polymerization tank through this insertion tube, it was found that scattered matter hardly adheres to the top plate of the polymerization tank, and the present invention was completed based on such knowledge.
Thus, according to the present invention, in the continuous production apparatus for polycarbonate resin using a plurality of polymerization tanks, the reaction liquid is contained in the polymerization phase in the polymerization tank in the polymerization tank or in the polymerization tank in the polymerization tank in at least one polymerization tank. An apparatus for producing a polycarbonate resin, characterized by being supplied to a gas phase part, is provided.
Here, it is preferable that the insertion pipe has an opening of the insertion pipe in a gas phase portion between the top plate of the polymerization tank and the liquid level of the reaction liquid in the polymerization tank.

The polymerization tank is preferably a vertical polymerization tank equipped with a stirring device.
Here, in the case of a vertical polymerization tank, it is preferable to supply the reaction liquid into the liquid phase in the vertical polymerization tank from the side surface of the vertical polymerization tank through an insertion tube or a transfer pipe.
Furthermore, the polycarbonate resin production apparatus is an apparatus having a plurality of vertical polymerization tanks connected in series and at least one horizontal polymerization tank following the vertical polymerization tank, and the polycarbonate resin is It is preferably produced by an ester exchange reaction between an aromatic dihydroxy compound and a carbonic acid diester.

  Next, according to the present invention, there is provided a method for producing a polycarbonate resin by an ester exchange reaction between an aromatic dihydroxy compound and a carbonic acid diester, and a raw material process for preparing a raw material molten mixture of an aromatic dihydroxy compound and / or a carbonic acid diester And a polycondensation step for continuously polycondensing the raw material melt mixture prepared in the original preparation step in the presence of a transesterification catalyst using a plurality of polymerization vessels, and the polycondensation step is at least in the polymerization vessel In one group, the reaction liquid obtained by the transesterification reaction is directly supplied to the liquid phase part in the polymerization tank, or the reaction liquid is supplied to the gas phase part through an insertion tube having an opening in the gas phase part in the polymerization tank. A method for producing a polycarbonate resin is provided.

Here, in the polycondensation step, the reaction liquid obtained by the transesterification reaction is supplied to at least one of the polymerization tanks through an insertion tube, and the insertion tube is formed between the top plate of the polymerization tank and the liquid level of the reaction liquid in the polymerization tank. It is preferable to have an opening portion of the insertion tube in the gas phase portion therebetween.
In the polycondensation step, a vertical polymerization tank is used as the polymerization tank, and the reaction liquid by the transesterification reaction is supplied to at least one of the polymerization tanks through the insertion pipe, and the insertion pipe or It is preferable to supply the reaction liquid into the liquid phase in the polymerization tank through a transfer pipe.
Furthermore, in the polycondensation step, a polycondensation reaction of an aromatic dihydroxy compound and a carbonic acid diester by transesterification using a plurality of vertical polymerization tanks connected in series and at least one horizontal polymerization tank following this. It is preferable to carry out.

  According to the present invention, it is possible to produce a polycarbonate resin with reduced generation of foreign matter.

  The best mode for carrying out the present invention (hereinafter, an embodiment of the present invention) will be described in detail below. The present invention is not limited to the following embodiments, and various modifications can be made within the scope of the invention. The drawings used are for explaining the present embodiment and do not represent the actual size.

(Polycarbonate resin)
In the present invention, the polycarbonate resin is preferably produced by polycondensation based on an ester exchange reaction between an aromatic dihydroxy compound and a carbonic acid diester.
Hereinafter, a method for producing a polycarbonate resin by using an aromatic dihydroxy compound and a carbonic acid diester as raw materials and continuously performing a polycondensation reaction in the presence of a transesterification catalyst will be described.

(Aromatic dihydroxy compounds)
Examples of the aromatic dihydroxy compound used in the present embodiment include compounds represented by the following general formula (1).

Here, in the general formula (1), A is a single bond or an optionally substituted linear, branched or cyclic divalent hydrocarbon group having 1 to 10 carbon atoms, or -O-, A divalent group represented by —S—, —CO— or —SO ₂ —. X and Y are a halogen atom or a C1-C6 hydrocarbon group. p and q are integers of 0 or 1. X and Y and p and q may be the same or different from each other.

Examples of the aromatic dihydroxy compound include bis (4-hydroxydiphenyl) methane, 2,2-bis (4-hydroxyphenyl) propane, 2,2-bis (4-hydroxy-3-methylphenyl) propane, 2, 2-bis (4-hydroxy-3-tert-butylphenyl) propane, 2,2-bis (4-hydroxy-3,5-dimethylphenyl) propane, 2,2-bis (4-hydroxy-3,5- Bisphenols such as dibromophenyl) propane, 4,4-bis (4-hydroxyphenyl) heptane, 1,1-bis (4-hydroxyphenyl) cyclohexane; 4,4′-dihydroxybiphenyl, 3,3 ′, 5, Biphenols such as 5′-tetramethyl-4,4′-dihydroxybiphenyl; bis (4-hydroxyphenyl) sulfone, bis (4-hydroxyphenyl) sulfide, bis (4-hydroxyphenyl) ether, bis (4-hydroxyphenyl) ketone and the like can be mentioned.
Among these, 2,2-bis (4-hydroxyphenyl) propane (“bisphenol A”, hereinafter sometimes abbreviated as BPA) is preferable.
In addition, in this Embodiment, it is not limited to these aromatic dihydroxy compounds mentioned above, Another aromatic dihydroxy compound can also be used. These aromatic dihydroxy compounds can be used alone or in combination.

  Moreover, you may substitute a part of aromatic dihydroxy compound mentioned above with another aliphatic dihydroxy compound in the range which does not impair the characteristic substantially. Such aliphatic dihydroxy compounds include dihydric alcohols. Specific examples include ethylene glycol, propylene glycol, butanediol, pentanediol, hexanediol, heptanediol, octanediol, dodecanediol, neopentylglycol, cyclohexanediol, and 1,4-dihydroxymethylcyclohexane.

(Carbonated diester)
Examples of the carbonic acid diester used in the present embodiment include compounds represented by the following general formula (2).

  Here, in the general formula (2), A ′ is an optionally substituted linear, branched, or cyclic monovalent hydrocarbon group having 1 to 10 carbon atoms. Two A's may be the same or different from each other.

Specific examples of the carbonic acid diester include symmetrical carbonic acid diesters such as dimethyl carbonate, diethyl carbonate, dipropyl carbonate, dibutyl carbonate, diphenyl carbonate, ditolyl carbonate, and di-t-butylphenyl carbonate. An asymmetric carbonic acid diester such as ethylphenyl carbonate can also be used. Moreover, in this Embodiment, it is also possible to use another carbonic acid diester in the range which does not impair the characteristic substantially.
Among these, diphenyl carbonate (hereinafter sometimes abbreviated as DPC) and substituted diphenyl carbonate are preferable. These carbonic acid diesters can be used alone or in admixture of two or more.

Moreover, said carbonic acid diester may substitute the quantity of the 50 mol% or less preferably 30 mol% or less with the dicarboxylic acid or dicarboxylic acid ester preferably.
Typical dicarboxylic acids or dicarboxylic acid esters include terephthalic acid, isophthalic acid, diphenyl terephthalate, diphenyl isophthalate, and the like. When substituted with such a dicarboxylic acid or dicarboxylic acid ester, a polyester carbonate is obtained.

These carbonic acid diesters (including the above-mentioned substituted dicarboxylic acid or dicarboxylic acid ester acid, the same shall apply hereinafter) are used in excess relative to the dihydroxy compound.
That is, it is usually used in a molar ratio of carbonic acid diester 1.01-1.30, preferably 1.02-1.20, relative to the aromatic dihydroxy compound. Under the same reaction conditions, the reaction rate increases as the molar ratio decreases, and the viscosity average molecular weight of the polycarbonate resin tends to increase. Further, when the molar ratio is increased in this range, the reaction rate is decreased and the viscosity average molecular weight tends to be decreased.
If the molar ratio is excessively small, the amount of terminal OH groups of the polycarbonate obtained by polycondensation increases, and the reactivity increases, but the thermal stability, hydrolysis resistance and the like tend to decrease. Moreover, when the molar ratio is excessively large, it tends to be difficult to produce a polycarbonate resin having a desired molecular weight.

(Transesterification catalyst)
The transesterification catalyst used in the present embodiment is not particularly limited, and is usually a catalyst used when producing polycarbonate by the transesterification method. In general, examples include basic compounds such as alkali metal compounds, beryllium or magnesium compounds, alkaline earth metal compounds, basic boron compounds, basic phosphorus compounds, basic ammonium compounds, and amine compounds.
Among these transesterification catalysts, an alkali metal compound is practically desirable. These transesterification catalysts may be used alone or in combination of two or more.
The transesterification catalyst is generally used in an amount of 1 × 10 ⁻⁹ to 1 × 10 ⁻¹ mol, preferably 1 × 10 ⁻⁷ to 1 × 10 ⁻² mol, relative to 1 mol of the aromatic dihydroxy compound. It is done.

Examples of the alkali metal compound include inorganic alkali metal compounds such as alkali metal hydroxides, carbonates and hydrogencarbonate compounds; organic alkali metal compounds such as salts with alkali metal alcohols, phenols and organic carboxylic acids. It is done. Here, examples of the alkali metal include lithium, sodium, potassium, rubidium, and cesium.
Specific examples of the alkali metal compound include, for example, sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium hydrogen carbonate, potassium hydrogen carbonate, lithium hydrogen carbonate, sodium carbonate, potassium carbonate, lithium carbonate, disodium salt of bisphenol A, Dipotassium salt, dilithium salt, phenol sodium salt, potassium salt, lithium salt and the like can be mentioned. Also, inorganic cesium salts such as cesium hydroxide, cesium carbonate, cesium hydrogencarbonate, organic acid cesium salts such as cesium acetate, cesium stearate, cesium alcoholates such as cesium methylate, cesium ethylate, cesium phenolate, bisphenol A Examples thereof include cesium salts of phenols such as dicesium salts.
Among these alkali metal compounds, cesium compounds are preferable, and cesium carbonate, cesium hydrogen carbonate, and cesium hydroxide are particularly preferable.

Examples of beryllium or magnesium compounds and alkaline earth metal compounds include inorganic alkaline earth metal compounds such as beryllium, magnesium, hydroxides and carbonates of alkaline earth metals; alcohols of these metals, phenols, organic And salts with carboxylic acids. Here, examples of the alkaline earth metal include calcium, strontium, and barium.
Specifically, for example, calcium hydroxide, barium hydroxide, magnesium hydroxide, strontium hydroxide, calcium hydrogen carbonate, barium hydrogen carbonate, magnesium hydrogen carbonate, strontium hydrogen carbonate, calcium carbonate, barium carbonate, magnesium carbonate, strontium carbonate Etc. These compounds are used alone or in combination.

  Examples of basic boron compounds include sodium salts, potassium salts, lithium salts, calcium salts, magnesium salts, barium salts, strontium salts, and the like of boron compounds. Here, as the boron compound, for example, tetramethylboron, tetraethylboron, tetrapropylboron, tetrabutylboron, trimethylethylboron, trimethylbenzylboron, trimethylphenylboron, triethylmethylboron, triethylbenzylboron, triethylphenylboron, tributyl Examples include benzylboron, tributylphenylboron, tetraphenylboron, benzyltriphenylboron, methyltriphenylboron, and butyltriphenylboron.

  Examples of basic phosphorus compounds include trivalent phosphorus compounds such as triethylphosphine, tri-n-propylphosphine, triisopropylphosphine, tri-n-butylphosphine, triphenylphosphine, and tributylphosphine, or derivatives thereof. And quaternary phosphonium salts.

  Examples of the basic ammonium compound include tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, trimethylethylammonium hydroxide, trimethylbenzylammonium hydroxide, trimethylphenylammonium hydroxide, Triethylmethylammonium hydroxide, triethylbenzylammonium hydroxide, triethylphenylammonium hydroxide, tributylbenzylammonium hydroxide, tributylphenylammonium hydroxide, tetraphenylammonium hydroxide, benzyltriphenylammonium hydroxide, methyltol Phenyl ammonium hydroxide, butyltriphenyl ammonium hydroxide, and the like.

  Examples of amine compounds include 4-aminopyridine, 2-aminopyridine, N, N-dimethyl-4-aminopyridine, 4-diethylaminopyridine, 2-hydroxypyridine, 2-methoxypyridine, 4-methoxypyridine, 2 -Dimethylaminoimidazole, 2-methoxyimidazole, imidazole, 2-mercaptoimidazole, 2-methylimidazole, aminoquinoline and the like.

(Production method of polycarbonate resin)
Next, the manufacturing method of polycarbonate resin is demonstrated.
In the production of polycarbonate resin, raw material melts of aromatic dihydroxy compound and carbonic acid diester compound as raw materials are prepared (primary process), and these compounds are melted in the presence of a transesterification catalyst in a plurality of polymerization tanks. Is carried out by carrying out a multistage polycondensation reaction using (polycondensation step). The reaction system may be any of a batch system, a continuous system, or a combination of a batch system and a continuous system. As the polymerization tank, a plurality of vertical polymerization tanks and at least one horizontal polymerization tank subsequent thereto are used. Usually, these polymerization tanks are connected in series and processed continuously.
After the polycondensation step, the reaction is stopped and the unreacted raw materials and reaction by-products in the polymerization reaction solution are devolatilized and removed, the step of adding a heat stabilizer, release agent, colorant, etc. You may add suitably the process etc. which form in the pellet of a particle size.

In the present embodiment, the raw material melt is a melt of a mixture of an aromatic dihydroxy compound and a carbonic acid diester, which may contain a transesterification catalyst. The polymerization reaction solution means a mixture with at least one selected from oligocarbonate (low molecular weight polycarbonate) and / or polycarbonate, aromatic dihydroxy compound, carbonic acid diester, transesterification catalyst, and other by-products. It may be included.
Next, each process of the manufacturing method will be described.

(Primary process)
The aromatic dihydroxy compound and carbonic acid diester used as a raw material for the polycarbonate resin are usually used in a batch, semi-batch or continuous stirring tank type apparatus in an atmosphere of an inert gas such as nitrogen or argon. Prepared as a raw material melt. For example, when bisphenol A is used as the aromatic dihydroxy compound and diphenyl carbonate is used as the carbonic acid diester, the temperature of the raw material melt is usually selected from the range of 20 ° C to 180 ° C, preferably 125 ° C to 160 ° C.
At this time, the ratio of the aromatic dihydroxy compound and the carbonic acid diester is adjusted so that the carbonic acid diester becomes excessive, and the carbonic acid diester is usually 1.01 mol to 1.30 mol with respect to 1 mol of the aromatic dihydroxy compound. Preferably, it is adjusted to a ratio of 1.02 mol to 1.20 mol.

(Polycondensation process)
The polycondensation by the transesterification reaction of the aromatic dihydroxy compound and the carbonic acid diester compound is usually carried out continuously in a multistage process of two or more stages, preferably 3 to 7 stages. Specific reaction conditions are temperature: 150 ° C. to 320 ° C., pressure: normal pressure to 0.01 Torr (1.3 Pa), and average residence time: 5 minutes to 150 minutes.
In each polymerization tank of a multistage process, in order to discharge | emit phenol byproduced with progress of a polycondensation reaction more effectively, it sets to higher temperature and a higher vacuum stepwise within said reaction conditions. In order to prevent quality deterioration such as hue of the obtained polycarbonate resin, it is preferable to set the temperature and the residence time as low as possible.

In the polycondensation in the multistage process, usually, a plurality of vertical reaction tanks equipped with stirring blades are connected, and a horizontal reaction tank is provided as a final process to increase the average molecular weight of the polycarbonate resin. The vertical reaction tank is usually installed in 2-5 pieces, preferably 3-4 pieces.
Here, the vertical reaction tank means that the rotation axis of the stirring blade is vertical (vertical direction). As the shape of the vertical reaction tank, one having a ratio (L / D) of the length L to the straight body length L to the inner diameter D of the reaction tank is 3 or less, preferably 0.5-3. The straight body length L of the reaction tank refers to the length between the tangential lines of the reaction tank when the reaction tank has a cylindrical mirror, and the upper or lower part of the reaction tank has a flat lid structure. Is the distance between the tangential line on one side of the side body and the other end face on the other side. The inner diameter D of the reaction tank indicates the distance in the region filled with the reaction solution.

  Examples of the type of stirring blades in the vertical reaction tank include turbine blades, paddle blades, fiddler blades, anchor blades, full zone blades (manufactured by Shinko Pantech Co., Ltd.), Sun Meller blades (manufactured by Mitsubishi Heavy Industries, Ltd.), Max. Examples thereof include blend blades (manufactured by Sumitomo Heavy Industries, Ltd.), helical ribbon blades, and twisted lattice blades (manufactured by Hitachi, Ltd.).

  Moreover, a horizontal reaction tank means that the rotating shaft of a stirring blade is a horizontal type (horizontal direction). As a stirring blade of a horizontal reaction tank, for example, a uniaxial stirring blade such as a disk type or a paddle type, HVR, SCR, N-SCR (manufactured by Mitsubishi Heavy Industries, Ltd.), Vivolak (Sumitomo Heavy Industries, Ltd.) Or a biaxial stirring blade such as a spectacle blade or a lattice blade (manufactured by Hitachi, Ltd.).

In addition, the transesterification catalyst used for the polycondensation of the aromatic dihydroxy compound and the carbonic acid diester compound is usually prepared in advance as an aqueous solution. The concentration of the catalyst aqueous solution is not particularly limited, and is adjusted to an arbitrary concentration according to the solubility of the catalyst in water. Further, instead of water, other solvents such as acetone, alcohol, toluene, phenol and the like can be selected.
The properties of water used for dissolving the catalyst are not particularly limited as long as the type and concentration of impurities contained are constant, but usually distilled water, deionized water, and the like are preferably used.

Next, a polycarbonate resin manufacturing apparatus to which the present embodiment is applied will be described with reference to the drawings.
FIG. 1 is a diagram illustrating an example of a polycarbonate resin production apparatus. In the production apparatus shown in FIG. 1, polycarbonate resin is a polycondensation process using a plurality of reaction tanks in a molten state of raw materials for preparing raw material melts of aromatic dihydroxy compounds and carbonic acid diester compounds as raw materials. And a polycondensation step to be reacted, after which the reaction is stopped and the unreacted raw materials and reaction byproducts in the polymerization reaction liquid are devolatilized and removed (not shown), a heat stabilizer, a release agent, Through a step of adding a colorant or the like (not shown) and a step of forming a polycarbonate resin into pellets having a predetermined particle size (not shown), the polycarbonate resin pellets are formed.

In the raw material process, a first raw material mixing tank 4 and a second raw material mixing tank 6 connected in series, and a supply pump 7a and a supply pipe 5b for supplying the prepared raw material melt to the polycondensation process are provided. ing. In addition, the opening part of the supply piping 5b is couple | bonded with the trunk | drum side surface of the 1st vertical polymerization tank 8 mentioned later. For example, anchor-type stirring blades 3a and 3b are provided in the first raw material mixing tank 4 and the second raw material mixing tank 6, respectively.
Further, diphenyl carbonate (hereinafter sometimes referred to as DPC), which is a carbonic acid diester, is supplied in a molten state from the DPC supply port 1 to the first raw material mixing tank 4. Bisphenol A (hereinafter sometimes referred to as BPA) which is a group dihydroxy compound is supplied in a powder state.

Next, in the polycondensation step, the first vertical polymerization tank 8, the second vertical polymerization tank 13, the third vertical polymerization tank 14, and the third vertical polymerization tank 14 connected in series are connected in series to the subsequent stage. A connected fourth horizontal polymerization tank 15 is provided.
The first vertical polymerization tank 8 and the second vertical polymerization tank 13 are connected by a supply pump 7b and a supply pipe 12a, and the opening of the supply pipe 12a is coupled to the side surface of the trunk of the second vertical polymerization tank 13. ing.
The second vertical polymerization tank 13 and the third vertical polymerization tank 14 are connected by a supply pump 7c and a supply pipe 12b, and the opening of the supply pipe 12b is coupled to the side surface of the trunk part of the third vertical polymerization tank 14. ing.
The third vertical polymerization tank 14 and the fourth horizontal polymerization tank 15 are connected by a supply pump 7d and a supply pipe 12c.
The first vertical polymerization tank 8, the second vertical polymerization tank 13, and the third vertical polymerization tank 14 are provided with max blend blades 9a, 9b, 9c, respectively. The fourth horizontal polymerization tank 15 is provided with a stirring blade 16.

  Further, by-product distillation pipes 10a, 10b, 10c, and 10d for discharging by-products generated by the polycondensation reaction are attached to the four polymerization tanks. The by-product distillation pipes 10a, 10b, 10c, and 10d are each connected to a condenser (not shown), and each polymerization tank is kept in a predetermined reduced pressure state by a decompression device (not shown). Be drunk.

  Here, in the present embodiment, the supply pump such as the raw material supply pump 7a and the supply pipe 5b, the supply pump 7b and the supply pipe 12a, the supply pump 7c and the supply pipe 12b, the supply pump 7d and the supply pipe 12c described above. A device that combines a pipe and a supply pipe is sometimes referred to as a “supply device”. Moreover, at least 1 of an aromatic dihydroxy compound, a carbonic acid diester, a transesterification catalyst, an oligocarbonate, and a polycarbonate can be transferred using a supply apparatus. At this time, other components may be included.

  Although not shown in the drawing, the polymerization reaction liquid discharged from the fourth horizontal polymerization tank 15 through the delivery pipe 12d thereafter stops the reaction and devolatilizes and removes unreacted raw materials and reaction byproducts in the polymerization reaction liquid. In addition, a pellet-like polycarbonate resin is obtained through a step of adding a heat stabilizer, a release agent, a colorant and the like and a step of forming a polycarbonate resin into pellets having a predetermined particle diameter.

In the polycarbonate resin manufacturing apparatus shown in FIG. 1, a DPC melt prepared at a predetermined temperature in a nitrogen gas atmosphere and a BPA powder measured in a nitrogen gas atmosphere are respectively connected to a DPC supply port 1 and a BPA supply port 2. To the first raw material mixing tank 4 continuously. When the liquid level of the first raw material mixing tank 4 exceeds a predetermined height, the raw material melt is transferred to the second raw material mixing tank 6 via the supply pipe 5a.
Next, the raw material melt is continuously supplied from the side surface of the body of the first vertical polymerization tank 8 into the polymerization reaction liquid in the first vertical polymerization tank 8 via the supply pipe 5b by the raw material supply pump 7a. Is done. As a catalyst, cesium carbonate in the form of an aqueous solution is continuously supplied from a catalyst supply port 5c in the middle of the supply pipe 5b for the raw material melt.

In the first vertical polymerization tank 8, a nitrogen atmosphere is maintained at, for example, a temperature of 220 ° C., a pressure of 13.33 KPa (100 Torr), a blade rotation speed of 160 rpm, and by-produced phenol is distilled from the by-product distillation pipe 10a. However, the liquid level 11a is kept constant so that the average residence time is 60 minutes, and the polycondensation reaction is performed. Next, the polymerization reaction liquid discharged from the first vertical polymerization tank 8 is continuously continuously supplied to the second vertical polymerization tank 13, the third vertical polymerization tank 14, and the fourth horizontal polymerization tank 15. The condensation reaction proceeds.
As shown in FIG. 1, in the present embodiment, the polymerization reaction liquid discharged from the bottom of the first vertical polymerization tank 8 is fed to the body of the second vertical polymerization tank 13 via the supply pipe 12a by the supply pump 7b. It is continuously fed into the polymerization reaction liquid in the second vertical polymerization tank 13 from the side of the part.
Further, the polymerization reaction liquid discharged from the bottom of the second vertical polymerization tank 13 is fed into the third vertical polymerization tank 14 from the side of the trunk of the third vertical polymerization tank 14 via the supply pipe 12b by the supply pump 7c. Is continuously fed into the polymerization reaction liquid.

  The reaction conditions in each polymerization tank are set so as to become high temperature, high vacuum, and low stirring speed as the polycondensation reaction proceeds. During the polycondensation reaction, the liquid surface levels 11a, 11b, and 11c are controlled so that the average residence time in each polymerization tank is, for example, about 60 minutes. In each polymerization tank, by-product phenol is a byproduct. It is distilled from the distillation pipes 10a, 10b, 10c, 10d.

As described above, in the polycarbonate resin manufacturing apparatus to which the present embodiment is applied, the raw material melt is fed into the polymerization reaction liquid in the first vertical polymerization tank 8 from the side surface of the body of the first vertical polymerization tank 8. Continuously supplied. Next, the polymerization reaction liquid discharged from the bottom of the first vertical polymerization tank 8 is continuously supplied into the polymerization reaction liquid in the second vertical polymerization tank 13 from the trunk side surface of the second vertical polymerization tank 13. Is done. Furthermore, the polymerization reaction liquid discharged from the bottom of the second vertical polymerization tank 13 is continuously supplied into the polymerization reaction liquid in the third vertical polymerization tank 14 from the trunk side surface of the third vertical polymerization tank 14. The
Thus, in a polycarbonate resin production apparatus, a supply pipe for supplying a raw material melt or a polymerization reaction liquid into a polymerization reaction liquid in a polymerization tank is provided on the side surface of the body portion of the polymerization tank. The amount of foreign matter in the final product, which is caused by the raw material melt or polymerization reaction liquid being scattered at the outlet, can be greatly reduced.

Next, FIG. 2 is a figure explaining other embodiment of the supply piping connected to a polymerization tank.
FIG. 2A and FIG. 2B are diagrams illustrating an insertion tube in which an opening of a supply pipe connected to the polymerization tank opens to a gas phase part in the polymerization tank. In FIG. 2 (a), a raw material melt or a polymerization reaction liquid is supplied to a vertical polymerization tank 22 equipped with a stirring blade 20 through a supply pipe 18 a by a supply pump 17, and a predetermined level while maintaining a liquid level 21. The transesterification reaction is carried out with an average residence time, and the polymerization reaction liquid is discharged from the bottom of the vertical polymerization tank 22 to the next step through the delivery pipe 23. The vertical polymerization tank 22 is kept in a reduced pressure state by a predetermined pressure reducing device (not shown). Further, by-product phenol and the like are distilled from the by-product distillation pipe 19.

As shown in FIG. 2A, the distal end portion of the supply pipe 18 a constitutes an insertion tube that is inserted into the vertical polymerization tank 22 from the upper top plate of the vertical polymerization tank 22. The opening of the insertion tube is located approximately in the middle between the upper top plate of the vertical polymerization tank 22 and the liquid level 21.
In FIG. 2B, similarly, the tip of the supply pipe 18b constitutes an insertion tube inserted into the vertical polymerization tank 22 from the upper top plate of the vertical polymerization tank 22, and the opening of the insertion pipe is , Located near the liquid level 21 of the vertical polymerization tank 22.
The length of the insertion tube is not particularly limited, but it is usually 30 cm or more from the upper top plate of the vertical polymerization tank 22, preferably closer to the liquid level. In addition, when the length of the insertion tube is excessively small, the raw material melt or the polymerization reaction liquid tends to scatter at the opening of the insertion tube and adhere to the vicinity of the opening of the insertion tube.
Thus, in the polycarbonate resin production apparatus, an insertion tube for supplying the raw material melt or the polymerization reaction liquid to the gas phase part between the upper top plate and the liquid surface in the polymerization tank is provided at the upper part of the polymerization tank. Thus, the amount of foreign matter in the final product, which is conventionally caused by the scattering of the raw material melt or polymerization reaction solution at the outlet of the supply port, can be greatly reduced.

Next, FIG.2 (c) and FIG.2 (d) are the examples which supply piping connects to the trunk | drum side surface of a polymerization tank similarly to FIG.
In FIG. 2C, the opening of the supply pipe 18 c opens at the wall surface on the side surface of the trunk portion of the vertical polymerization tank 22. In this case, for example, there is a possibility that the design width of the vertical polymerization tank 22 may be expanded, such as ease of mounting the heat exchange coil of the vertical polymerization tank 22.
FIG. 2D shows an example in which a raw material melt or a polymerization reaction liquid is supplied by an insertion pipe (supply pipe 18 d) provided on the side surface of the trunk portion of the vertical polymerization tank 22. The insertion pipe (supply pipe 18 d) is inserted into the vertical polymerization tank 22 from a direction substantially perpendicular to the axis of the stirring blade 20.

As described above in detail, according to the apparatus for producing an aromatic polycarbonate to which the present embodiment is applied, it is possible to produce a high-molecular-weight aromatic polycarbonate with reduced generation of foreign matter.
The aromatic polycarbonate obtained in this way is a building material such as a sheet, a container such as a water bottle, an optical headlamp lens, optical lenses such as glasses, an optical recording material such as an optical disk, a light guide plate of a liquid crystal display, etc. Can be suitably used.

It is a figure which shows an example of the manufacturing apparatus of polycarbonate resin. It is a figure explaining other embodiment of supply piping connected to a polymerization tank. It is a figure for demonstrating the manufacturing apparatus of the conventional polycarbonate resin.

Explanation of symbols

3a, 3b ... anchor type stirring blades, 4 ... first raw material mixing tank, 5a, 5b, 12a, 12b, 12c, 18a, 18b, 18c, 18d, 18e ... supply piping, 5c ... catalyst supply port, 6 ... second Raw material mixing tank, 7a ... Raw material supply pump, 7b, 7c, 7d, 17, 17e ... Supply pump, 8 ... First vertical polymerization tank, 9a, 9b, 9c ... Max blend blade, 10a, 10b, 10c, 10d, 19, 19e ... by-product distillation pipe, 11a, 11b, 11c, 21, 21e ... liquid level, 13 ... second vertical polymerization tank, 14 ... third vertical polymerization tank, 15 ... fourth horizontal polymerization tank, 16, 20, 20e ... stirring blades, 22, 22e ... vertical polymerization tank, 12d, 23, 23e ... delivery piping

Claims (6)

In a continuous production apparatus for polycarbonate resin using a plurality of polymerization tanks,
In at least 1 group polymerization vessel, gas in the polymerization vessel by insertion tube having an opening to the gas-phase portion between the liquid surface of the reaction liquid reaction solution in the polymerization tank top plate and said polymerization vessel of An apparatus for producing a polycarbonate resin, characterized by being supplied to a phase section.   The said polymerization tank is a vertical polymerization tank provided with a stirring apparatus, The manufacturing apparatus of the polycarbonate resin of Claim 1 characterized by the above-mentioned.   The apparatus for producing a polycarbonate resin according to claim 2, wherein the reaction liquid is supplied into a liquid phase in the polymerization tank from the side surface of the polymerization tank through the insertion pipe or the transfer pipe. The manufacturing apparatus includes:
A plurality of vertical polymerization tanks connected in series;
An apparatus having at least one horizontal polymerization tank following the vertical polymerization tank, and
The polycarbonate resin production apparatus according to claim 1, wherein the polycarbonate resin is produced by an ester exchange reaction between an aromatic dihydroxy compound and a carbonic acid diester. A process for producing a polycarbonate resin by an ester exchange reaction between an aromatic dihydroxy compound and a carbonic acid diester,
An original process for preparing a raw material melt mixture of an aromatic dihydroxy compound and / or a carbonic acid diester;
A polycondensation step for continuously polycondensing the raw material melt mixture prepared in the original preparation step in the presence of a transesterification catalyst using a plurality of polymerization tanks, and
The polycondensation step, said at least 1 group of the polymerization vessel, the reaction solution by an ester exchange reaction, the gas phase portion between those the polymerization liquid level of the reaction liquid in the top plate and the polymerization vessel inside vessel A method for producing a polycarbonate resin, characterized in that the gas-phase portion is supplied by an insertion tube having an opening in the tube.   6. The method for producing a polycarbonate resin according to claim 5, wherein the polycondensation step uses a plurality of vertical polymerization tanks connected in series and at least one horizontal polymerization tank subsequent thereto.

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