JP2009279754A - Method for producing aromatic polycarbonate resin composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing an aromatic polycarbonate resin composition with stable quality by uniformly mixing additives including a heat stabilizer into an aromatic polycarbonate resin. <P>SOLUTION: The method for producing the aromatic polycarbonate resin composition includes a polycarbonate supply process for supplying a molten aromatic polycarbonate continuously to an extruder, the extrusion process in which the aromatic polycarbonate and the heat stabilizer are mixed and extruded by the extruder, the pellet forming process for forming the pellets of the aromatic polycarbonate extruded from the extruder, and the pellet circulation supply process in which part of the aromatic polycarbonate pellets, while being taken out to be added continuously with the heat stabilizer, are supplied continuously to the extruder to which the aromatic polycarbonate is supplied. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for producing an aromatic polycarbonate resin composition, and more particularly to a method for producing an aromatic polycarbonate resin composition by transesterification.

  In recent years, aromatic polycarbonate resins have been widely used in OA parts, automotive parts, building materials, etc. as engineering plastics that are excellent in mechanical properties such as impact resistance, heat resistance, and transparency. . In particular, taking advantage of properties such as impact resistance and transparency, it is widely used as an optical material in applications such as optical lenses, recording disks, sheets, and bottles.

  As a method for producing such an aromatic polycarbonate resin, the aromatic diol and the carbonic acid diester are transesterified in a molten state, and the aromatic polycarbonate resin is continuously removed while removing by-products such as phenol from the system. A method for obtaining the above-mentioned is conventionally known as a so-called melting method.

  Here, when an aromatic polycarbonate resin is used as a material, various heat stabilizers are often added and used in order to maintain and improve the performance. These heat stabilizers are usually mixed with an aromatic polycarbonate by a kneading method using an extruder, and dispersed and homogenized (see Patent Document 1).

JP-A-8-259687

By the way, for example, when an aromatic polycarbonate resin is produced by a melting method, the molten aromatic polycarbonate resin and various additives such as a heat stabilizer are usually mixed in an extruder provided at a later stage of the production line. . Then, the aromatic polycarbonate resin extruded from the extruder is then formed into pellets of a predetermined size to become a product.
However, many additives added to the aromatic polycarbonate resin have a powdery or liquid form, and the amount used is extremely small. For this reason, when aromatic polycarbonate resin and an additive are mixed with an extruder, there exists a problem that an additive is unevenly distributed and it is often not mixed uniformly.
In this case, a method of adding to the extruder in the form of a masterbatch composed of an additive and a suitable polymer in advance can be considered. However, when a master batch is prepared using a mixer such as a Henschel mixer, the powdered additive is often classified and a uniform dispersed state is often not obtained. Moreover, a liquid additive may isolate | separate after preparing a masterbatch.

In addition, since the melting method is generally a method for continuously producing an aromatic polycarbonate resin, a transition product is generated when the product is switched. Since such a transition product is out of specification, it is usually disposed of as a production loss product.
However, from the viewpoint of product yield and resource saving, it is not preferable to dispose of such production loss products, and it is desirable to use them effectively. However, recycling such production loss products may deteriorate the thermal stability of the product and lower the product value.

  An object of the present invention is to provide a method for producing an aromatic polycarbonate resin composition having stable quality by uniformly mixing an additive such as a heat stabilizer and an aromatic polycarbonate resin.

  In order to solve the above-mentioned problems, the present inventors have conducted intensive studies. As a result, the aromatic polycarbonate pellets containing the thermal stabilizer are pneumatically transported by a branch pipe obtained by branching the pneumatic transport pipe, and heat is transferred to this. It has been found that when the stabilizer is added and continuously supplied to the extruder, the above-mentioned production loss product can be used effectively and the influence on the quality can be minimized, and the present invention has been completed based on such knowledge.

  Thus, according to the present invention, there is provided a process for producing an aromatic polycarbonate resin composition containing a heat stabilizer, comprising a polycarbonate supply step for continuously supplying an aromatic polycarbonate in a molten state to an extruder; Mixing the aromatic polycarbonate supplied in the supply process with a heat stabilizer and extruding from the extruder, and forming the pellets by pelletizing the aromatic polycarbonate extruded from the extruder in the extrusion process A part of the pellets of the aromatic polycarbonate pelletized in the process and the pellet forming process are collected, and the pellets with the heat stabilizer attached are supplied to the polycarbonate while the heat stabilizer is continuously added to the pellets. Aromatic polycarbonate is supplied in the process The process for producing an aromatic polycarbonate resin composition characterized by having a pellet circulation supplying step of supplying a continuous extruder is provided.

  Here, in the method for producing an aromatic polycarbonate resin composition to which the present invention is applied, the method further comprises a pneumatic transportation step of pneumatically transporting the pellets of the aromatic polycarbonate pelletized by the pellet forming step through the transportation piping, and the transportation piping. It is preferable to pneumatically transport a part of the pellets of the aromatic polycarbonate obtained in the pellet forming step by a branch pipe branched from the pipe.

Next, in the method for producing an aromatic polycarbonate resin composition to which the present invention is applied, in the pellet circulation supply step, it is preferable that the thermal stabilizer added to the pellets of the aromatic polycarbonate is in a liquid state.
Here, it is preferable that the heat stabilizer attached to the pellets of the aromatic polycarbonate in the pellet circulation supply step is an acidic compound or a derivative thereof.
Furthermore, the heat stabilizer is preferably a sulfonic acid or an ester thereof which is liquid and optionally substituted with an alkyl group having 1 to 10 carbon atoms.

Moreover, in the manufacturing method of the aromatic polycarbonate resin composition to which the present invention is applied, in the pellet circulation supplying step, 0.001 part by weight to 1 part by weight of the heat stabilizer is added to 100 parts by weight of the pellets of the aromatic polycarbonate. It is preferable to continuously add to the pellets of the aromatic polycarbonate.
Furthermore, in the pellet circulation supply step, 0.5 to 5 parts by weight of aromatic polycarbonate pellets with a heat stabilizer attached are supplied to the extruder with respect to 100 parts by weight of the aromatic polycarbonate supplied to the extruder. It is preferable.

Further, in the method for producing an aromatic polycarbonate resin composition to which the present invention is applied, the viscosity average molecular weight (Mv ₁ ) of the aromatic polycarbonate pelletized in the pellet forming step is such that the thermal stabilizer and The viscosity average molecular weight (Mv ₂ ) or less (Mv ₁ ≦ Mv ₂ ) of the molten aromatic polycarbonate to be mixed is preferable.
In the extrusion step, the heat stabilizer is preferably mixed in an amount of 0.002 parts by weight or less with respect to 100 parts by weight of the aromatic polycarbonate.
In the polycarbonate supplying step, the aromatic polycarbonate supplied to the extruder is preferably obtained by a polycondensation reaction between an aromatic dihydroxy compound and a carbonic acid diester using a basic compound as a catalyst.

  According to the present invention, an aromatic polycarbonate resin composition with stable quality can be produced. In addition, it can be expected to improve the yield of products by simple means and contribute to resource saving.

  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 produced by melt 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 melt 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 0-2. X and Y and p and q may be the same or different from each other.

  Specific examples of the aromatic dihydroxy compound include, for example, bis (4-hydroxydiphenyl) methane, 2,2-bis (4-hydroxyphenyl) propane, and 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-dibromophenyl) propane, 4,4-bis (4-hydroxyphenyl) heptane, bisphenols such as 1,1-bis (4-hydroxyphenyl) cyclohexane; 4,4′-dihydroxybiphenyl, 3,3 ′ Biphenols such as 5,5'-tetramethyl-4,4'-dihydroxybiphenyl; bis (4-hydroxyphenyl) Sulfone, bis (4-hydroxyphenyl) sulfide, bis (4-hydroxyphenyl) ether, bis (4-hydroxyphenyl) ketone.

  Among these, 2,2-bis (4-hydroxyphenyl) propane (“bisphenol A”, hereinafter sometimes abbreviated as BPA) is preferable. These aromatic dihydroxy compounds can be used alone or in admixture of two or more.

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

Here, in general formula (2), A 'is a C1-C10 linear, branched or cyclic monovalent hydrocarbon group which may be substituted. Two A ′ may be the same or different from each other.
In addition, as a substituent on A ′, a halogen atom, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a phenyl group, a phenoxy group, a vinyl group, a cyano group, an ester group, an amide group, A nitro group etc. are illustrated.

Specific examples of the carbonic acid diester include substituted diphenyl carbonates such as diphenyl carbonate and ditolyl carbonate; and dialkyl carbonates such as dimethyl carbonate, diethyl carbonate, and di-t-butyl carbonate.
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, the same shall apply hereinafter) are used in excess relative to the dihydroxy compound.
That is, the molar ratio of the carbonic acid diester to the aromatic dihydroxy compound is preferably 1.01 or more, particularly preferably 1.02 or more, preferably 1.30 or less, particularly preferably 1.20 or less. . When the molar ratio is smaller than 1.01, the terminal OH group of the obtained polycarbonate resin increases, and the thermal stability of the resin tends to deteriorate. In addition, when the molar ratio is larger than 1.30, the transesterification reaction rate decreases, and it becomes difficult to produce a polycarbonate resin having a desired molecular weight, and the residual amount of carbonic acid diester in the resin increases. This is not preferable because it may cause odor of the molded product or the molded product.

(Transesterification catalyst)
Examples of the transesterification catalyst used in the present embodiment include a catalyst usually used for producing an aromatic polycarbonate by a transesterification method, and are not particularly limited. 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 or an alkaline earth metal compound has a great effect in that it uniformly disperses a small amount of the heat stabilizer targeted in the present embodiment in the aromatic polycarbonate resin composition. . These transesterification catalysts may be used alone or in combination of two or more.
The amount of the transesterification catalyst used is usually preferably 1 × 10 ⁻⁹ mol or more, particularly preferably 1 × 10 ⁻⁷ mol or more, and more preferably 1 × 10 ^{−1 to} 1 mol of the aromatic dihydroxy compound. It is used in the range of not more than mol, particularly preferably not more than 1 × 10 ⁻² mol.

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.
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.

  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 the basic phosphorus compound include trivalent phosphine 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, methyltriphenylammonium hydroxide Sid, butyl triphenyl ammonium hydroxide, and the like.

  Examples of the amine compound 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.

(Method for producing aromatic polycarbonate)
Next, the manufacturing method of an aromatic polycarbonate is demonstrated.
For the production of aromatic polycarbonate, a mixture containing an aromatic dihydroxy compound and a carbonic acid diester as raw materials is prepared (primary process), and a mixture of these compounds is reacted in a molten state in the presence of a transesterification reaction catalyst. The polycondensation reaction is performed in a multistage manner using a vessel (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, but a continuous system is preferable from the viewpoint of productivity and quality stability. In the case of a continuous type, the reactor is generally composed of a plurality of reactors arranged in series, and preferably a plurality of vertical reactors and at least one horizontal reactor following this are used.
In the present embodiment, after the polycondensation step, a biaxial type having a vent port that can use an extruder to add a heat stabilizer and preferably devolatilize and remove unreacted raw materials and reaction byproducts in the reaction solution. Using an extruder.
Next, each process of the manufacturing method of an aromatic polycarbonate is demonstrated.

(Primary process)
The aromatic dihydroxy compound and carbonic acid diester used as the raw material for the aromatic polycarbonate 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 molten mixture. For example, when bisphenol A is used as the aromatic dihydroxy compound and diphenyl carbonate is used as the carbonic acid diester, the melt mixing temperature is preferably 120 ° C. or higher, particularly preferably 125 ° C. or higher, and more preferably 180 ° C. or lower, particularly preferably Is selected from a range of 160 ° C. or lower.

  At this time, the mixing ratio of the aromatic dihydroxy compound and the carbonic acid diester is adjusted so that the carbonic acid diester becomes excessive, and the ratio of the carbonic acid diester to the 1 mol of the aromatic dihydroxy compound is preferably 1.01 mol or more. It is particularly preferably adjusted to 1.02 mol or more, more preferably 1.30 mol or less, and particularly preferably 1.20 mol or less.

(Polycondensation process)
The polycondensation by the transesterification reaction between the aromatic dihydroxy compound and the carbonic acid diester is usually carried out continuously in a multistage system 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 one-stage average residence time: 5 minutes to 150 minutes.
In each reactor when the polycondensation process is performed in multiple stages, in order to more effectively discharge the by-product phenol with the progress of the polycondensation reaction, the reaction conditions are usually higher and higher in steps. Set to vacuum. In addition, in order to prevent quality deterioration of the hue etc. of the aromatic polycarbonate resin obtained, it is preferable to set a low temperature and a short residence time as much as possible.

When the polycondensation step is performed in a multi-stage system, preferably, an average molecular weight of the aromatic polycarbonate resin is provided by providing a plurality of vertical reactors and / or at least one reactor excellent in thin film evaporation performance following this. Increase. Usually 3 to 6 reactors, preferably 4 to 5 reactors are installed.
Here, as a reactor having excellent thin film evaporation performance, for example, a thin film reactor, a centrifugal thin film evaporation reactor, a surface renewable biaxial kneading reactor, a biaxial horizontal stirring reactor, a wet wall reactor, a free A perforated plate reactor that polymerizes while dropping, a perforated plate reactor with wire that polymerizes while dropping along a wire, and the like are used.

  Examples of the type of agitator blades in a vertical reactor include turbine blades, paddle blades, fiddler blades, anchor blades, full zone blades (manufactured by Shinko Environmental Solution Co., Ltd.), Sun Meller blades (manufactured by Mitsubishi Heavy Industries, Ltd.), and Max Blend blades. (Manufactured by Sumi Heavy Equipment Systems Co., Ltd.), helical ribbon wing, twisted lattice wing (manufactured by Hitachi Plant Technology Co., Ltd.) and the like.

  Moreover, a horizontal reactor means that the rotating shaft of a stirring blade is a horizontal type (horizontal direction). As a stirring blade of a horizontal reactor, for example, a single-shaft type stirring blade such as a disk type or a paddle type, HVR, SCR, N-SCR (manufactured by Mitsubishi Heavy Industries, Ltd.), viola rack (manufactured by Sumijuki Equipment Systems Co., Ltd.) Or a twin-shaft type stirring blade such as a spectacle blade or a lattice blade (manufactured by Hitachi Plant Technology Co., Ltd.).

In addition, the transesterification catalyst used for the polycondensation of the aromatic dihydroxy compound and the carbonic acid diester 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. Moreover, it can replace with water and other organic solvents, such as acetone, alcohol, toluene, and phenol, can also be used.
The water used for dissolving the catalyst is not particularly limited as long as the kind and concentration of impurities contained are constant, but usually distilled water, deionized water, and the like are preferably used.

(Manufacturing equipment)
Next, an example of a method for producing an aromatic polycarbonate resin composition to which the present embodiment is applied will be specifically described based on the drawings.
FIG. 1 is a diagram illustrating an example of an apparatus for producing an aromatic polycarbonate resin composition. In the production apparatus shown in FIG. 1, the aromatic polycarbonate is prepared by preparing a raw material aromatic dihydroxy compound and a carbonic acid diester, and a polycondensation reaction of these raw materials in a molten state using a plurality of reactors. It is manufactured through processes.
Thereafter, the reaction is stopped and the unreacted raw material and reaction by-products in the polymerization reaction solution are devolatilized and removed, the step of adding a heat stabilizer, a release agent, a colorant, etc., the aromatic polycarbonate resin The pellet of the aromatic polycarbonate resin composition is formed through a step of forming into a pellet having a diameter.

In the raw material process, a first raw material preparation tank 2a and a second raw material preparation tank 2b connected in series, and a raw material supply pump 4a for supplying the prepared raw material to the polycondensation process are provided. For example, anchor-type stirring blades 3a and 3b are provided in the first raw material preparation tank 2a and the second raw material preparation tank 2b, respectively.
In addition, DPC is supplied in a molten state from the DPC supply port 1a-1 to the first raw material preparation tank 2a, and bisphenol A (hereinafter referred to as BPA) which is an aromatic dihydroxy compound is supplied from the BPA supply port 1b. Is supplied in a powder state, and bisphenol A is dissolved in the molten diphenyl carbonate.

  Next, in the polycondensation step, the first vertical reactor 6a, the second vertical reactor 6b and the third vertical reactor 6c connected in series, and the subsequent stage of the third vertical reactor 6c are connected in series. A connected fourth horizontal reactor 9a is provided. The first vertical reactor 6a, the second vertical reactor 6b, and the third vertical reactor 6c are provided with max blend blades 7a, 7b, 7c, respectively. The fourth horizontal reactor 9a is provided with a lattice blade 10a.

  The four reactors are equipped with distilling tubes 8a, 8b, 8c, and 8d for discharging by-products generated by the polycondensation reaction. The distillation pipes 8a, 8b, 8c and 8d are connected to the condensers 81a, 81b, 81c and 81d, respectively, and the respective reactors are kept in a predetermined reduced pressure state by the decompression devices 82a, 82b, 82c and 82d. Be drunk.

In the apparatus for producing an aromatic polycarbonate resin composition 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 supplied to a DPC supply port 1a. -1 and the BPA supply port 1b are continuously supplied to the first raw material preparation tank 2a. When the liquid level of the first raw material preparation tank 2a exceeds the same height as the highest position in the transfer pipe, the raw material mixture is transferred to the second raw material preparation tank 2b.
Next, the raw material mixture is continuously supplied to the first vertical reactor 6a via the raw material supply pump 4a. As the catalyst, an aqueous cesium carbonate solution is continuously supplied from the catalyst supply port 5a in the middle of the transfer pipe of the raw material mixture.

  In the first vertical reactor 6a, under a nitrogen atmosphere, for example, a temperature of 220 ° C., a pressure of 13.33 kPa (100 Torr), the rotation speed of the Max blend blade 7a is maintained at 160 rpm, and by-produced phenol is removed from the distillation pipe 8a. The polycondensation reaction is carried out while keeping the liquid level constant so that the average residence time is 60 minutes while distilling. Next, the polymerization reaction liquid discharged from the first vertical reactor 6a is continuously continuously supplied to the second vertical reactor 6b, the third vertical reactor 6c, and the fourth horizontal reactor 9a, The condensation reaction proceeds. The reaction conditions in each reactor are usually set so as to become high temperature, high vacuum, and low stirring speed as the polycondensation reaction proceeds, but are appropriately adjusted according to the required performance such as the desired molecular weight. During the polycondensation reaction, the liquid surface level is controlled so that the average residence time in each reactor is, for example, about 60 minutes. In each reactor, by-produced phenol is added to the distillation tubes 8b, 8c, Distilled from 8d.

  In the present embodiment, by-products such as phenol are continuously liquefied and recovered from the condensers 81a and 81b attached to the first vertical reactor 6a and the second vertical reactor 6b, respectively. The Further, a cold trap (not shown) is provided between the condensers 81c and 81d and the decompression devices 82c and 82d attached to the third vertical reactor 6c and the fourth horizontal reactor 9a, respectively. Living organisms are continuously condensed and solidified.

Next, the aromatic polycarbonate extracted from the fourth horizontal reactor 9a is supplied to a biaxial extruder 11a having a three-stage vent port in a molten state. From the additive supply lines 12a, 12b and 12c to the extruder 11a, for example, heat stabilizers, antioxidants, weathering agents, mold release agents, lubricants, antistatic agents, plasticizers, pigments, dyes, fillers, reinforcing Various additives such as additives, flame retardants, polymers such as other resins and rubber are supplied.
Here, examples of the heat stabilizer include phosphorus stabilizers, hindered phenol stabilizers, sulfur stabilizers, epoxy stabilizers, hindered amine stabilizers, and the like. Specific examples of preferable heat stabilizers will be described later.

A heat stabilizer may be used independently and may be used in combination. The addition amount is not particularly limited, but it is usually used in the range of 0.0001 to 0.5 parts by weight, preferably 0.001 to 0.2 parts by weight with respect to 100 parts by weight of the aromatic polycarbonate. In particular, in the case of a heat stabilizer supplied in liquid form, it is 0.005 parts by weight or less, preferably 0.002 parts by weight or less, more preferably 0.001 parts by weight or less.
Here, in the present embodiment, the thermal stabilizer is continuously attached to the aromatic polycarbonate pellets as will be described later, and is continuously supplied from the additive supply line 12a to the extruder 11a.

The aromatic polycarbonate and the heat stabilizer are melt-mixed inside the extruder 11a and extruded from the outlet. When the aromatic polycarbonate is extruded from the extruder 11a, the aromatic polycarbonate is formed into a strand shape by holes (not shown) provided in the outlet portion.
The strand-like aromatic polycarbonate is cooled by cooling water via the strand bath 13a, pelletized by the strand cutter 14a, removed from the water by the sieving machine 15a, and then introduced into the product silos 16a and 16b.

Moreover, in this preferred embodiment, a part of the aromatic polycarbonate resin composition (aromatic polycarbonate pellets), which is the final product and product, is introduced into the product silo 16c by branching the pneumatic transportation pipe. .
An inert gas such as air or nitrogen compressed by a compressor (not shown) is supplied to the pneumatic transport pipe, and the aromatic polycarbonate pellets can be pneumatically transported.

(Continuous attachment of heat stabilizer)
In the present embodiment, the aromatic polycarbonate pellets stored in the product silo 16c are preferably supplied continuously to the blender 21a through an aerodynamic transport pipe. Although not shown in FIG. 1, in order to stably supply the blender 21a stably, a hopper and a quantitative feeder are provided for supplying aromatic polycarbonate pellets, and supply from the product silo 16c to the hopper is intermittent. It is also possible to continuously supply the aromatic polycarbonate pellets from the hopper to the blender 21a using a quantitative feeder.

The heat stabilizer is continuously supplied to the blender 21a through the heat stabilizer supply port 22a. In the blender 21a, the thermal stabilizer is continuously attached to the aromatic polycarbonate pellets. The blending time is preferably 1 minute to 20 minutes, more preferably 5 minutes to 10 minutes. If the blending time is too long, the apparatus tends to be excessive, and if it is too short, the entire aromatic polycarbonate pellet tends to be insufficiently attached.
In this case, the amount of the thermal stabilizer to be continuously added to the aromatic polycarbonate pellets in the blender 21a is not particularly limited. Usually, the thermal stabilizer is 0.001 part by weight to 100 parts by weight of the aromatic polycarbonate pellets. 1 part by weight, preferably 0.005 part by weight to 0.5 part by weight, and more preferably 0.01 part by weight to 0.2 part by weight.

If the amount of the heat stabilizer to be attached to the aromatic polycarbonate pellets is excessively large, the dispersibility of the heat stabilizer in the extruder 11a is deteriorated, the color tone of the aromatic polycarbonate obtained as a product is deteriorated, the quality is uneven, etc. Tend to occur.
Moreover, when the amount of the heat stabilizer to be attached to the aromatic polycarbonate pellets is excessively small, the amount of pellets supplied into the extruder 11a tends to increase in order to ensure a predetermined amount of the heat stabilizer. In this case, a large amount of aromatic polycarbonate pellets that have received a heat history in advance are supplied into the extruder 11a. As a result, not only the color tone of the aromatic polycarbonate obtained as a product deteriorates, but also the operation of the extruder 11a becomes unstable, and the blender 21a tends to be overloaded.

(Continuous supply of aromatic polycarbonate pellets)
Next, the aromatic polycarbonate pellets, to which the heat stabilizer is continuously added by the blender 21a, are continuously circulated and supplied to the extruder 11a through the additive supply line 12a as described above, and melted in the extruder 11a. Mixed with aromatic polycarbonate.
Here, the term “attachment” refers to a state in which the heat stabilizer is adhered onto the aromatic polycarbonate pellets by mixing.
Although the blender 21a will not be specifically limited if it is an apparatus which can be mixed continuously, For example, a ribbon blender etc. are illustrated. The aromatic polycarbonate pellets are preferably handled under an inert gas atmosphere such as nitrogen because the product quality deteriorates due to oxygen entrained when supplied to the extruder 11a. In particular, introducing nitrogen into the blender 21a is effective for suppressing thermal degradation of the product.

In addition, a plurality of heat stabilizers may be supplied to the blender 21a, and additives other than the heat stabilizer, such as a mold release agent, a colorant, and an ultraviolet absorber, may be simultaneously supplied.
Furthermore, the additive supplied from the additive supply lines 12b and 12c may be supplied in the same manner as the additive supply line 12a.

  The amount of the aromatic polycarbonate resin composition continuously circulated and supplied to the extruder 11a is usually 0 when the aromatic polycarbonate supplied to the extruder 11a from the fourth horizontal reactor 9a is 100 parts by weight. .1 to 10 parts by weight, preferably 0.5 to 5 parts by weight, more preferably 1 to 4 parts by weight. If the amount of the aromatic polycarbonate resin composition circulated and supplied to the extruder 11a is excessively small, the effect of the present invention is hardly generated, and if it is excessively large, the thermal stability of the product tends to deteriorate.

  Moreover, although the magnitude | size, shape, etc. of an aromatic polycarbonate pellet are not specifically limited, Usually, what was processed into 20 mm or less in size is preferable. Moreover, although a granular shape, an indeterminate shape, a flat plate shape, a cylindrical shape, or the like can be used, the granular shape and the cylindrical shape are preferable from the viewpoint of easy availability, and the cylindrical shape is particularly preferable.

  As described above, in the present embodiment, a part of the pellets of the aromatic polycarbonate pelletized as a product is taken out, and a heat stabilizer is continuously added thereto, and further, the heat stabilizer attached to the pellets. Is continuously fed to the extruder. For this reason, it becomes possible to uniformly mix the heat stabilizer with the molten aromatic polycarbonate resin in the extruder. Furthermore, by continuously supplying pellets to which the heat stabilizer is continuously added into the extruder, an aromatic polycarbonate resin composition having a stable quality can be obtained without causing any alteration or separation of the heat stabilizer. Can do.

In the present embodiment, the aromatic polycarbonate pellet supplied from the product silo 16c contains the heat stabilizer itself, and is further supplied with the heat stabilizer and supplied to the extruder 11a. For this reason, the thermal stability of the obtained aromatic polycarbonate resin is remarkably improved, and the quality degradation of the final product is greatly reduced.
In the present embodiment, by employing the above method, the heat stabilizer can be sufficiently dispersed in the aromatic polycarbonate resin composition even if the amount of the heat stabilizer is small. In particular, in this embodiment, even when the amount of the heat stabilizer is 0.002 parts by weight or less with respect to 100 parts by weight of the molten aromatic polycarbonate resin in the extruder 11a, the heat stabilizer is stabilized in the aromatic polycarbonate resin. Can be supplied.

In the present embodiment, it is particularly effective when the heat stabilizer to be used is a liquid or an acidic compound or a derivative thereof.
Here, there is no restriction | limiting in particular as an acidic compound used as a heat stabilizer, For example, the compound (So-called reaction terminator and deactivator, etc. which neutralize the basic transesterification catalyst normally used for a polycondensation reaction) Compound).

  Specifically, hydrochloric acid, nitric acid, boric acid, sulfuric acid, sulfurous acid, phosphoric acid, phosphorous acid, hypophosphorous acid, polyphosphoric acid, adipic acid, ascorbic acid, aspartic acid, azelaic acid, adenosine phosphoric acid, benzoic acid, Formic acid, valeric acid, citric acid, glycolic acid, glutamic acid, glutaric acid, cinnamic acid, succinic acid, acetic acid, tartaric acid, oxalic acid, p-toluenesulfinic acid, p-toluenesulfonic acid, naphthalenesulfonic acid, nicotinic acid, picrine Examples thereof include Bronsted acids such as acid, picolinic acid, phthalic acid, terephthalic acid, propionic acid, benzenesulfinic acid, benzenesulfonic acid, malonic acid, maleic acid, and esters thereof, acid halides, and salts. These may be used alone or in combination of two or more.

  Among these acidic compounds, liquid sulfonic acid or an ester thereof which may be substituted with an alkyl group having 1 to 10 carbon atoms is preferable. Examples of the sulfonic acid include benzenesulfonic acid, toluenesulfonic acid, and naphthalenesulfonic acid. Examples of the sulfonic acid ester include methyl ester, ethyl ester, butyl ester, octyl ester, and phenyl ester. Among these, butyl p-toluenesulfonate is particularly preferable.

In the present embodiment, the viscosity average molecular weight (Mv ₁ ) of the aromatic polycarbonate in the aromatic polycarbonate pellet to which the heat stabilizer is attached is equal to or less than the viscosity average molecular weight (Mv ₂ ) of the molten aromatic polycarbonate in the extruder 11a. It is preferable that That is, it is preferable that Mv ₁ ≦ Mv ₂ . Among them, the difference in viscosity average molecular weight (Mv ₂ −Mv ₁ ) is 5,000 or less, preferably 3,000 or less, particularly preferably 2,000 or less.
When the viscosity average molecular weight (Mv ₁ ) of the aromatic polycarbonate in the aromatic polycarbonate pellets impregnated with the heat stabilizer is excessively larger than the viscosity average molecular weight (Mv ₂ ) of the molten aromatic polycarbonate in the extruder 11a, the viscosity-average molecular weight (Mv ₂₎ to the viscosity-average molecular weight difference between _{(Mv 1) (Mv 2 -Mv} 1) is excessively large, dispersibility of the heat stabilizer tends to be lowered.

  Moreover, in this Embodiment, the structure which uses the aromatic polycarbonate resin composition manufactured using the extruder 11a as an aromatic polycarbonate pellet which attaches a heat stabilizer, and returns to the extruder 11a again is employ | adopted. By doing so, a cut mistake product generated at the final stage in the production of the aromatic polycarbonate resin, a production loss product generated due to product switching, and the like can be used as pellets to which the thermal stabilizer is attached. It is also effective for stabilizing the supply amount of the heat stabilizer, ensuring dispersibility in the molten polymer, preventing thermal deterioration of the recycled product, and maintaining the product quality. As a result, it can be expected to improve the yield of products, save resources, and stabilize product quality.

FIG. 2 is a diagram showing another example of an apparatus for producing an aromatic polycarbonate resin composition when a plurality of blenders are used and an additive such as a heat stabilizer is attached. Components similar to those in FIG. 1 are denoted by the same reference numerals, and description thereof is omitted.
In the apparatus for producing an aromatic polycarbonate resin composition shown in FIG. 2, a blender 21b is newly provided in contrast to the apparatus for producing an aromatic polycarbonate resin composition shown in FIG. In addition, a heat stabilizer supply port 22b is provided separately.
The aromatic polycarbonate pellets can be supplied to the blender 21b similarly to the blender 21a by branching the pneumatic transportation pipe. Further, a heat stabilizer and other additives can be supplied from the heat stabilizer supply port 22b, and can be attached to the aromatic polycarbonate pellets in the blender 21b.
In the blender 21b, after the heat stabilizer and other additives are added, they are circulated and supplied to the extruder 11a through the additive supply line 12b.

Next, specific embodiments of the present invention will be described by way of examples. However, the present invention is not limited to these examples unless it exceeds the gist.
In addition, the analysis of the aromatic polycarbonate resin composition in a following example and a comparative example was performed with the following method.

(1) Viscosity average molecular weight (Mv)
The aromatic polycarbonate resin composition is dissolved in methylene chloride, the intrinsic viscosity [η] in methylene chloride at 20 ° C. is measured using an Ubbelohde viscometer, and the viscosity average molecular weight (Mv) is calculated according to the following formula (1). Asked.
In this example, since components other than the aromatic polycarbonate resin in the aromatic polycarbonate resin composition are in a very small amount, the viscosity average molecular weight (Mv) of the aromatic polycarbonate resin in the aromatic polycarbonate resin composition and the aromatic The viscosity average molecular weight (Mv) of the polycarbonate resin composition was considered the same.

(2) Initial hue After the aromatic polycarbonate resin composition was dried at 120 ° C. for 6 hours under a nitrogen atmosphere, an injection molded piece of 60 mm × 60 mm × 3 mm thickness was obtained using a J75EII type injection molding machine manufactured by Nippon Steel Works, Ltd. The operation of molding under the conditions of a resin temperature of 360 ° C. and a molding cycle of 30 seconds was repeated.
And the yellow index (YI) value of the injection molded product obtained by the 6th shot-the 15th shot was measured using the color tester (Konica Minolta Co., Ltd. CM-3700d), and the average value and the standard deviation were calculated. . A smaller YI value indicates better hue and better quality, and a smaller standard deviation indicates less color unevenness and stable quality.

(3) Hue after heat retention test In (2) above, from the 16th shot, the molding cycle was 10 minutes, and the injection molding operation was repeated to obtain injection molded products up to the 22nd shot.
The YI value of the 60 mm × 60 mm × 3 mm thick injection molded product obtained in the 20th to 22nd shots was measured using a color tester (CM-3700d manufactured by Konica Minolta Co., Ltd.), and the average value was calculated. A smaller YI value indicates better hue and better quality.

Example 1
The apparatus shown in FIG. 2 was used as an apparatus for producing an aromatic polycarbonate resin composition. In FIG. 2, the DPC supply port 1a-1 to DPC and the BPA supply port 1b to BPA were controlled at an internal temperature of 140 ° C. at a constant molar ratio (DPC / BPA = 1.050) in a nitrogen atmosphere. One raw material preparation tank 2a was continuously supplied to obtain a uniform molten state.

After that, through the second raw material preparation tank 2b similarly controlled at 140 ° C., the raw material supply pump 4a was used to continuously supply the first vertical reactor 6a so that the supply amount per unit time was constant. Then, an aqueous solution of cesium carbonate as a catalyst was continuously supplied from the catalyst supply port 5a to 0.5 × 10 ⁻⁶ mol with respect to 1 mol of BPA.

The internal temperature of the first vertical reactor 6a is controlled to 220 ° C., the pressure is controlled to 13.3 kPa, and a valve (not shown) provided in the discharge line at the bottom of the tank so that the average residence time is 1.5 hours. Was adjusted to keep the liquid level constant.
The polymerization liquid discharged from the first vertical reactor 6a was continuously continuously supplied to the second vertical reactor 6b, the third vertical reactor 6c, and the fourth horizontal reactor 9a. The second vertical reactor 6b had an internal temperature of 260 ° C., a pressure of 4 kPa, and an average residence time of 1.5 hours. The third vertical reactor 6c has an internal temperature of 270 ° C., a pressure of 70 Pa, and an average residence time of 1 hour, and the fourth horizontal reactor 9a has an internal temperature of 270 ° C., a pressure of 200 Pa, and an average residence time of 1.5 hours. .

  This aromatic polycarbonate was supplied to the biaxial extruder 11a so as to be 97 parts by weight per unit time in a molten state. At this time, the product silo 16c is stocked with aromatic polycarbonate pellets (average length 3 mm, average diameter 3 mm, Mv = 15,000) containing a heat stabilizer produced by the same method as described below. The blender 21a was supplied at 1.5 parts by weight per unit time. In addition, as the blender 21a, a continuous ribbon blender was used, and nitrogen was circulated. The blending time in the blender 21a was 8 minutes.

  Further, butyl p-toluenesulfonate is supplied from the heat stabilizer supply port 22a as a heat stabilizer by a small metering pump (not shown) so as to be 0.0005 parts by weight per unit time, and is continuously supplied to the aromatic polycarbonate pellets. Attached. And it supplied to the extruder 11a continuously from the additive supply line 12a.

  Further, aromatic polycarbonate pellets are supplied from the product silo 16c to the blender 21b (using a continuous ribbon blender in the same manner as the blender 21a) in the same manner as described above to supply 1.5 parts by weight per unit time, and nitrogen is supplied. Circulated. The blending time in the blender 21b was 8 minutes.

  Here, 0.005 parts by weight of tris (2,4-di-t-butylphenyl) phosphite as a heat stabilizer from the supply port 22b per unit time, and stearic acid monoglyceride as a mold release agent at a rate of 0.005 per unit time. It was continuously supplied to the blender 21b so as to be 03 parts by weight. And it was made to adhere continuously to an aromatic polycarbonate pellet, and it supplied to the extruder 11a continuously from the additive supply line 12b.

The polycarbonate resin composition discharged from the biaxial extruder 11a in a molten state in a strand is cooled and solidified by a strand bath 13a, pelletized by a strand cutter 14a, and then non-standard size pellets by a sieving machine 15a. And stocked in product silos 16a-16c as appropriate.
The obtained polycarbonate resin composition had a viscosity average molecular weight (Mv) of 15,000, an initial YI = 1.28, a standard deviation of 0.015, and a YI = 3.21 after the residence heat stability test.

(Example 2)
An aromatic polycarbonate resin composition was produced in the same manner as in Example 1 except that the viscosity average molecular weight (Mv) of the aromatic polycarbonate pellets stocked in the product silo 16c was 14,500.
The resulting aromatic polycarbonate resin composition had a viscosity average molecular weight (Mv) of 15,000, an initial hue of YI = 1.25, a standard deviation of 0.013, and a YI after a residence heat stability test of 3.20. there were.

(Example 3)
An aromatic polycarbonate resin composition was produced in the same manner as in Example 1 except that the viscosity average molecular weight (Mv) of the aromatic polycarbonate pellets stocked in the product silo 16c was 27,000.
The resulting aromatic polycarbonate resin composition had a viscosity average molecular weight (Mv) of 15,400, an initial hue of YI = 1.37, a standard deviation of 0.031, and a YI after retention heat stability test of 3.43. there were.

Example 4
An aromatic polycarbonate resin composition was produced in the same manner as in Example 1 except that the aromatic polycarbonate pellets to be supplied to the blenders 21a and 21b were supplied in an amount of 3 parts by weight per unit time. The blend time was 4 minutes each.
The resulting aromatic polycarbonate resin composition had a viscosity average molecular weight (Mv) of 15,000, an initial hue of YI = 1.40, a standard deviation of 0.012, and a YI after retention heat stability test of 3.65. there were.

(Comparative Example 1)
An aromatic polycarbonate resin composition was produced in the same manner as in Example 1 except that the aromatic polycarbonate pellets containing no heat stabilizer were stocked in the product silo 16c and supplied.
The resulting aromatic polycarbonate resin composition had a viscosity average molecular weight (Mv) of 15,000, an initial hue of YI = 1.55, a standard deviation of 0.017, and a YI after retention heat stability test of 3.90. Yes, compared to the above examples.

(Comparative Example 2)
An aromatic polycarbonate resin composition was produced in the same manner as in Comparative Example 1 except that nitrogen was not passed through the blenders 21a and 21b.
The aromatic polycarbonate resin composition thus obtained had a viscosity average molecular weight (Mv) of 15,000, an initial hue of YI = 1.59, a standard deviation of 0.024, and a YI after residence heat stability test of 4.05. Yes, compared to the above examples.

(Comparative Example 3)
6 parts by weight of the aromatic polycarbonate pellets stocked in the product silo 16c were charged into a Henschel mixer, and 0.002 part by weight of butyl p-toluenesulfonate was added, followed by thorough mixing for 10 minutes. Thus, the pellet prepared by the batch method was supplied to the blender 21a so that it might become 1.5 weight part per unit time. In addition, the same continuous ribbon blender as Example 1 was used for the blender 21a, and it carried out similarly to Example 1 except not having supplied butyl p-toluenesulfonate from the heat stabilizer supply port 22a.
The obtained polycarbonate resin composition had a viscosity average molecular weight (Mv) of 15,000, an initial hue of YI = 1.49, a standard deviation of 0.157, and a YI after retention heat stability test of 3.77. .

(Comparative Example 4)
In Comparative Example 3, 6 parts by weight of aromatic polycarbonate pellets stocked in product silo 16c, 0.02 part by weight of tris (2,4-di-t-butylphenyl) phosphite, 0.12 part by weight of stearic acid monoglyceride Was previously mixed in a Henschel mixer for 10 minutes and prepared in a batch system, and the pellets were continuously supplied to the blender 21b at 1.5 parts by weight per unit time. In addition, the same continuous ribbon blender as Example 1 was used for the blender 21b, and tris (2,4-di-t-butylphenyl) phosphite and stearic acid monoglyceride were not supplied from the supply port 22b. It carried out similarly to the comparative example 3. The obtained polycarbonate resin composition had a viscosity average molecular weight (Mv) of 15,000, an initial hue of YI = 1.53, a standard deviation of 0.170, and a YI after retention heat stability test of 3.84. .

It is a figure which shows an example of the manufacturing apparatus of an aromatic polycarbonate resin composition. It is a figure which shows an example of the manufacturing apparatus of an aromatic polycarbonate resin composition in the case of using several blenders and attaching additives, such as a heat stabilizer.

Explanation of symbols

2a ... 1st raw material preparation tank, 2b ... 2nd raw material preparation tank, 3a, 3b ... Anchor type stirring blade, 4a ... Raw material supply pump, 5a ... Catalyst supply port, 6a ... 1st vertical reactor, 6b ... 2nd Vertical reactor, 6c ... 3rd vertical reactor, 7a, 7b, 7c ... Max blend blade, 8a, 8b, 8c, 8d ... Distillation tube, 9a ... Fourth horizontal reactor, 10a ... Grid blade, 11a Extruder, 12a, 12b, 12c ... Additive supply line, 13a ... Strand bath, 14a ... Strand cutter, 15a ... Sieving machine, 16a, 16b, 16c ... Product silo, 21a, 21b ... Blender, 22a, 22b ... Heat Stabilizer supply port, 81a, 81b, 81c, 81d ... condenser, 82a, 82b, 82c, 82d ... decompression device

Claims (10)

A method for producing an aromatic polycarbonate resin composition containing a heat stabilizer,
A polycarbonate supply step for continuously supplying the molten aromatic polycarbonate to the extruder;
The extrusion step of mixing the aromatic polycarbonate supplied in the polycarbonate supply step with the heat stabilizer by the extruder and extruding from the extruder,
Pellet forming step of pelletizing aromatic polycarbonate extruded from the extruder in the extrusion step to form aromatic polycarbonate pellets;
A part of the pellets of the aromatic polycarbonate pelletized in the pellet forming step is collected, and the pellets to which the thermal stabilizer is attached are supplied to the polycarbonate while the thermal stabilizer is continuously added to the pellets. A pellet circulation supply step for continuously supplying to an extruder to which aromatic polycarbonate is supplied in the step;
A process for producing an aromatic polycarbonate resin composition, comprising: A pneumatic transportation step of pneumatically transporting the pellets of the aromatic polycarbonate pelletized by the pellet formation step by a transportation pipe;
2. The production of an aromatic polycarbonate resin composition according to claim 1, wherein a part of the pellets of the aromatic polycarbonate obtained in the pellet forming step is pneumatically transported by a branch pipe branched from the transport pipe. Method.   The method for producing an aromatic polycarbonate resin composition according to claim 1 or 2, wherein the thermal stabilizer attached to the pellets of the aromatic polycarbonate in the pellet circulation supply step is in a liquid state.   The aromatic polycarbonate resin composition according to any one of claims 1 to 3, wherein the thermal stabilizer attached to the pellets of the aromatic polycarbonate in the pellet circulation supply step is an acidic compound or a derivative thereof. Manufacturing method.   The aromatic according to any one of claims 1 to 4, wherein the heat stabilizer is a liquid sulfonic acid or an ester thereof which may be substituted with an alkyl group having 1 to 10 carbon atoms. A method for producing a polycarbonate resin composition.   In the pellet circulation supply step, 0.001 to 1 part by weight of a heat stabilizer is continuously added to the pellets of the aromatic polycarbonate with respect to 100 parts by weight of the pellets of the aromatic polycarbonate. Item 6. A method for producing an aromatic polycarbonate resin composition according to any one of Items 1 to 5.   In the pellet circulation supply step, 0.5 to 5 parts by weight of the aromatic polycarbonate pellets to which the heat stabilizer is attached are added to the extruder with respect to 100 parts by weight of the aromatic polycarbonate supplied to the extruder. The method for producing an aromatic polycarbonate resin composition according to claim 1, wherein the aromatic polycarbonate resin composition is supplied. The viscosity-average molecular weight of pelletized aromatic polycarbonate in pellet forming step (Mv ₁₎ is a viscosity-average molecular weight of the aromatic polycarbonate in a molten state is mixed with the thermal stabilizer in the extruder in the extrusion step (Mv ₂ The method for producing an aromatic polycarbonate resin composition according to claim _{1, wherein} (Mv ₁ ≦ Mv ₂ ):   The aromatic according to any one of claims 1 to 8, wherein in the extrusion step, the heat stabilizer is mixed in an amount of 0.002 parts by weight or less with respect to 100 parts by weight of the aromatic polycarbonate. A method for producing a polycarbonate resin composition.   The aromatic polycarbonate supplied to the extruder in the polycarbonate supplying step is obtained by a polycondensation reaction between an aromatic dihydroxy compound and a carbonic acid diester using a basic compound as a catalyst. The method for producing an aromatic polycarbonate resin composition according to any one of 1 to 9.

Images