JPH07173277A - Aromatic polycarbonate improved in melt flow characteristic - Google Patents

Abstract

PURPOSE:To provide an aromatic polycarbonate provided with impact resistance with good reproducibility, improved in melt flow characteristics while retaining the excellent properties, and suitable for injection molding. CONSTITUTION:An aromatic polycarbonate having a molecular weight distribution Mw/Mn of 2.3 to 2.8 is mixed with a compound which comprises a carbonate obtained from one molecule of an aromatic dihydroxy compound, the constituent unit of the aromatic polycarbonate, and has the ends completely blocked.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aromatic polycarbonate, more specifically, injection molding in which the target impact resistance is imparted with good reproducibility and the melt flowability is improved while maintaining the excellent properties. To an aromatic polycarbonate suitable for.

[0002]

2. Description of the Related Art Aromatic polycarbonate is a high-strength and high-rigidity engineering plastic that is excellent in heat resistance and impact resistance, and also excellent in transparency, weather resistance, dimensional stability, and electrical properties. Is used for.
However, since aromatic polycarbonate has a high melt viscosity, injection molding of precision parts with complicated shapes, thin-walled products, and large, thick-walled products is accompanied by problems caused by insufficient fluidity of the molten resin. Was there.

Further, since the aromatic polycarbonate has a very small dependency of the melt viscosity on the shear rate, it is difficult to improve the fluidity by injection pressure, and the only effective means for increasing the fluidity under molding conditions is to raise the temperature. It was However, molding at high temperature causes problems such as yellowing due to oxidative deterioration of the resin, residual distortion of the molded product, and delay of the molding cycle.

Conventionally, as a method for improving the melt fluidity of an aromatic polycarbonate resin, there is a modification method by adding a plasticizer or alloying with a resin having a good melt fluidity.
As a modification method by adding a plasticizer, a method of adding a carbonic acid diester to an aromatic polycarbonate (Japanese Patent Publication No.
6789), 0.1 to 1 relative to aromatic polycarbonate
Method of adding 0% by weight of terephthalic acid ester and / or isophthalic acid ester (Japanese Patent Publication No. 40-2126)
3) A method of adding one or more fatty acids (Japanese Patent Laid-Open No. 61-162520). As a modification method by alloying, aromatic polycarbonate is
S resin (JP-B 38-15225), polyethylene (JP-B 40-13663), polypropylene (JP-B 4040)
-13664), ethylene-propylene block copolymer (JP-B-40-24191), butyl rubber (JP-B-42-18823), polystyrene (JP-B-43-62).
95), a composition of a compatibility enhancer with polystyrene (Japanese Patent Publication No. 44-11551), polyester carbonate (Japanese Patent Publication No. 56-51185), polyalkylene isophthalate or poly (alkylene isophthalate-alkylene terephthalate) (Japanese Patent Publication No. 57-43572). ), Polyvinyl acetal (Japanese Patent Publication No. 3-74267), cellulose ester (Japanese Patent Publication No. 3-74269), polyethylene terephthalate (JP-A-4-296351), polyester elastomer and styrene-based copolymer (JP-A-4-345).
658) and the like.

As described above, it is possible to obtain an aromatic polycarbonate having improved melt fluidity by adding a plasticizer or alloying with a different resin. However, such a method impairs some of the excellent properties of the aromatic polycarbonate such as heat resistance, impact resistance, transparency, and dimensional stability in order to improve the target melt flowability. It cannot be said that it is a method for improving melt fluidity while maintaining various excellent properties inherent in aromatic polycarbonate resins, inevitably causing denaturation or modification.

Further, as a technique for improving melt flowability without adding a substance other than aromatic polycarbonate, weight average molecular weight, molecular weight distribution, gel permeation chromatography (hereinafter referred to as Japanese Patent Laid-Open No. 5-186676) , Abbreviated as “GPC”) and a method for producing and mixing aromatic polycarbonates having different molecular weights so that the molecular weight at the peak top and the weight ratio of the low molecular weight portion and the high molecular weight portion fall within a specific range. . The aromatic polycarbonate obtained by this method can exhibit excellent melt flowability while maintaining impact resistance, but has a problem in reproducibility of target physical properties of products.

Japanese Patent Laid-Open No. 5-186676 discloses a method for producing a mixture of aromatic polycarbonates having different molecular weights. After polymerizing one of the polymers to be mixed, the aromatic polycarbonates having different molecular weights are polymerized in the presence thereof. However, when this method is carried out by the interfacial polycondensation method, not only the volumetric efficiency of the reactor is deteriorated, but also the second or subsequent polymerization reaction is performed by alkaline hydrolysis of the synthesized aromatic polycarbonate. There is a risk of doing it. Even in the melting method, the aromatic polycarbonate synthesized first may be decomposed by phenolysis to cause a change in molecular weight, a mixture having a target molecular weight cannot be obtained, and it is difficult to impart desired physical properties with good reproducibility.

Further, even in the case of mixing aromatic polycarbonates having clear molecular weights, in the case of mixing in a solution, since the molecular weights of the aromatic polycarbonates to be mixed are relatively high, it is necessary to obtain a homogeneous mixture. It is necessary to dilute it to reduce its viscosity, and as a result, an extremely large amount of solvent must be handled, and the mixed composition is susceptible to changes in concentration. Mixing in powder or molten state also has the problem that it is difficult to obtain a homogeneous mixture continuously.Therefore, when mixing for a long time, the composition of the product mixture with respect to the mixing ratio fluctuates, and high quality molded products are obtained. It may not be reproducibly obtained, or the physical properties of the product such as impact resistance may change.

As described above, according to the conventional technique, the target impact resistance is imparted with good reproducibility, and the melt flowability is improved while maintaining the excellent properties thereof, which is suitable for injection molding. Was hard to get.

[0010]

DISCLOSURE OF THE INVENTION The present invention provides an aromatic compound suitable for injection molding, which has a target impact resistance with good reproducibility and has improved melt flowability while maintaining its excellent properties. The purpose is to obtain polycarbonate.

[0011]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have found that Mw / Mn = 2.3-
2.8 (Mw represents a weight average molecular weight, Mn represents a number average molecular weight), and an ordinary aromatic polycarbonate having a regular molecular weight distribution is added to an aromatic dihydroxy compound which is a constitutional unit of the aromatic polycarbonate. The present inventors have completed the present invention by finding that the melt fluidity can be enhanced by adding a compound whose end is completely blocked with a carbonate from a molecule.

That is, in the present invention, the molecular weight distribution is Mw / Mn =
To the aromatic polycarbonates represented by 2.3 to 2.8,
Melt fluidity obtained by adding a compound in which one end of a molecule of an aromatic dihydroxy compound, which is a constituent unit of the aromatic polycarbonate, is completely sealed (hereinafter referred to as "dicarbonate"). In the GPC chromatogram of the aromatic polycarbonate obtained by this method, the height of the peak of dicarbonate is 2% or more and 8% or less with respect to the height of the main peak. It relates to an aromatic polycarbonate.

The present invention will be described in detail below. The aromatic dihydroxy compound used in the present invention is a compound represented by the following formula (I) (formula 1) or (II) (formula 2).

HO-Ar1-X-Ar2-OH (I)

HO-Ar3-OH (II)

In the above formula, Ar1, Ar2 and A
r3 is a monocyclic divalent aromatic group, that is, a phenylene group or a phenylene group having a substituent, and the substituent is a halogen atom, a nitro group, an alkyl group, a cycloalkyl group, an alkenyl group, or an aralkyl group. Alternatively, a hydrocarbon group such as an aryl group, an alkoxy group, and the like can be given.

Ar1 and Ar2 are both p-phenylene, m-phenylene or o-phenylene, or one is p-phenylene and the other is m-phenylene or o-phenylene. Are preferred, and it is particularly preferred that both Ar1 and Ar2 are p-phenylene groups. X is a linking group that connects Ar1 and Ar2, and is a single bond or a divalent hydrocarbon group, and further -O.
-, - S -, - SO -, - SO 2 -, - it may be a group containing atoms other than carbon and hydrogen CO- like. The divalent hydrocarbon group means a saturated hydrocarbon group such as methylene, ethylene, 2,2-propylidene, cyclohexylidene,
Examples thereof include an alkylidene group having a substituent such as cyclohexylidene, but also include a group substituted with an aryl group and the like, and a hydrocarbon group containing an aromatic group or other unsaturated hydrocarbon group. May be.

Specific examples of the aromatic dihydroxy compound include bis (4-hydroxyphenyl) methane and 1,1-
Bis (4'-hydroxyphenyl) ethane, 1,2-bis (4'-hydroxyphenyl) ethane, bis (4-hydroxyphenyl) phenylmethane, bis (4-hydroxyphenyl) diphenylmethane, bis (4-hydroxyphenyl) -1-naphthylmethane, 1,1-bis (4'-hydroxyphenyl) -1-phenylethane,
2,2-bis (4'-hydroxyphenyl) propane ["bisphenol A"], 2- (4'-hydroxyphenyl) -2- (3'-hydroxyphenyl) propane, 2,2-bis (4'- Hydroxyphenyl) butane, 1,1-bis (4′-hydroxyphenyl) isobutane, 2,2-bis (4′-hydroxyphenyl) octane, 2,2-bis (3′-methyl-4′-hydroxyphenyl) Propane, 2,2-bis (3'-ethyl-
4'-hydroxyphenyl) propane, 2,2-bis (3'-n-propyl-4'-hydroxyphenyl) propane, 2,2-bis (3'-isopropyl-4'-hydroxyphenyl) propane, 2, 2-bis (3'-s
ec-butyl-4′-hydroxyphenyl) propane,
2,2-bis (3′-tert-butyl-4′-hydroxyphenyl) propane, 2,2-bis (3′-cyclohexyl-4′-hydroxyphenyl) propane, 2,
2-bis (3'-allyl-4'-hydroxyphenyl)
Propane, 2,2-bis (3'-methoxy-4'-hydroxyphenyl) propane, 2,2-bis (3 ', 5'
-Dimethyl-4'-hydroxyphenyl) propane,
2,2-bis (2 ', 3', 5 ', 6'-tetramethyl-4'-hydroxyphenyl) propane, 2,2-bis (3'-chloro-4'-hydroxyphenyl) propane, 2, 2-bis (3 ', 5'-dichloro-4'-hydroxyphenyl) propane, 2,2-bis (3'-bromo-4'-hydroxyphenyl) propane, 2,2-bis (3', 5 '-Dibromo-4'-hydroxyphenyl) propane, 2,2-bis (2 ', 6'-dibromo-
3 ', 5'-dimethyl-4'-hydroxyphenyl) propane, bis (4-hydroxyphenyl) cyanomethane, 1-cyano-3,3-bis (4'-hydroxyphenyl) butane, 2,2-bis (4 Bis (hydroxyaryl) alkanes such as'-hydroxyphenyl) hexafluoropropane,

1,1-bis (4'-hydroxyphenyl) cyclopentane, 1,1-bis (4'-hydroxyphenyl) cyclohexane, 1,1-bis (4'-hydroxyphenyl) -3,3,5 -Bis (hydroxyaryl) cycloalkanes such as trimethylcyclohexane, 1,1-bis (4'-hydroxyphenyl) cycloheptane and 2,2-bis (4'-hydroxyphenyl) adamantane, 4,4'-dihydroxydiphenyl ether , 4,4'-dihydroxy-3,3'-dimethyldiphenyl ether, ethylene glycol bis (4-hydroxyphenyl) ether and other dihydroxydiaryl ethers, 4,4'-dihydroxydiphenyl sulfide, 4,4'-dihydroxy-3 Dihydroxy such as 3'-dimethyldiphenyl sulfide Aryl sulfides, 4,4'-dihydroxydiphenyl sulfoxide, 4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfoxide and other dihydroxydiaryl sulfoxides, 4,4'-dihydroxydiphenyl sulfone, 4,4'-dihydroxy- Dihydroxydiarylsulfones such as 3,3′-dimethyldiphenylsulfone, bis (4-hydroxyphenyl) ketone, bis (4
Bis (hydroxyaryl) ketones such as -hydroxy-3-methylphenyl) ketone,

Further, 6,6'-dihydroxy-3,
3,3 ', 3'-Tetramethylspiro (bis) indane ["spirobiindane bisphenol"], trans-
2,3-bis (4'-hydroxyphenyl) -2-butene, 9,9-bis (4'-hydroxyphenyl) fluorene, 3,3-bis (4'-hydroxyphenyl) -2
-Butanone, 1,6-bis (4'-hydroxyphenyl) -1,6-hexanedione, 1,1-dichloro-
2,2-bis (4'-hydroxyphenyl) ethylene,
1,1-dibromo-2,2-bis (4′-hydroxyphenyl) ethylene, 1,1-dichloro-2,2-bis (5′-phenoxy-4′-hydroxyphenyl) ethylene, α, α, α ', Α'-Tetramethyl-α, α'-
Bis (4-hydroxyphenyl) -p-xylene, α,
α, α ', α'-tetramethyl-α, α'-bis (4-
Hydroxyphenyl) -m-xylene, 4,4′-dihydroxybiphenyl and the like can be mentioned. In addition to the above aromatic dihydroxy compounds, hydroquinone, resorcin, etc. are also used. You may use these individually or in mixture of 2 or more types. The aromatic dihydroxy compound used particularly preferably in the present invention is bisphenol A.

In the present invention, a carbonyl halide is preferably used as a raw material for forming a carbonate bond in the interfacial polycondensation method. For example, phosgene, carbonyl bromide, carbonyl iodide, carbonyl fluoride and the like, and a mixture thereof may be used. Further, a compound having the ability to form a haloformate group, for example,
It may be trichloromethyl chloroformate, which is a dimer of phosgene, or bis (trichloromethyl) carbonate, which is a trimer of phosgene. Usually, it is preferable to use phosgene. In the case of the melting method, carbonic acid diesters such as diphenyl carbonate, ditertiary butyl phenyl carbonate, ditolyl carbonate, bis (chlorophenyl) carbonate, m-cresyl carbonate, and dinaphthyl carbonate are used, and among them, diphenyl carbonate is preferably used. .

In the present invention, when the aromatic polycarbonate is produced by the interfacial polycondensation method, the aromatic polycarbonate is used as a molecular weight regulator (also referred to as an end capping agent) for controlling the final molecular weight and as a raw material of dicarbonate. A monohydroxy compound is used. Examples of the aromatic monohydroxy compound include phenol, p-tertiarybutylphenol, o-cresol, m-cresol and p.
-Cresol, o-ethylphenol, m-ethylphenol, p-ethylphenol, o-cumylphenol, m-cumylphenol, p-cumylphenol, o
-Cyclohexylphenol, m-cyclohexylphenol, p-cyclohexylphenol, o-octylphenol, m-octylphenol, p-octylphenol, o-nonylphenol, m-nonylphenol, p-nonylphenol, o-methoxyphenol,
m-methoxyphenol, p-methoxyphenol, o
-Chlorophenol, m-chlorophenol, p-chlorophenol, o-bromophenol, m-bromophenol, p-bromophenol, pentabromophenol, pentachlorophenol, β-naphthol, α-naphthol and the like. These alone or 2
You may use it in mixture of 2 or more types. Phenol or p-tert-butylphenol is preferable because of easy availability.

The dicarbonate used in the present invention is a known technique (Daniel J. Brunell) from the aromatic dihydroxy compound and the carbonyl halide compound.
and Thomas G. Shannon, Mac
romolecules 1991, vol. 24, p.
3035 to 3044) and a bishaloformate of an aromatic dihydroxy compound and the above-mentioned aromatic monohydroxy compound in a theoretical ratio of 1: 2 in a molar ratio of 1 to 2 in a suitable organic solvent that becomes a homogeneous system. It can be easily synthesized by reacting with a binder. The organic solvent is a solvent used in the interfacial polycondensation method, for example, dichloromethane, chloroform, 1,2-dichloroethane,
Aliphatic chlorinated compounds such as 1,2-dichloroethylene, trichloroethane, tetrachloroethane, dichloropropane, etc., or a mixture thereof are usually used. This dicarbonate may be a combination of any of the above aromatic dihydroxy compounds, carbonyl halide compounds, and monovalent hydroxyaromatic compounds, or dicarbonates having different structures may be mixed and used. The dicarbonate preferably used in the present invention is a compound obtained from bisphenol A bischloroformate obtained from bisphenol A and phosgene and phenol, or p-tertiarybutylphenol.

As the parent aromatic polycarbonate used in the method of the present invention, a usual aromatic polycarbonate having a well-ordered molecular weight distribution obtained by a known interfacial polycondensation method or melting method can be applied. The ordered molecular weight distribution is indicated by the polydispersity index (Mw / Mn) obtained from the ratio of Mw and Mn measured by GPC being 2.3 or more and 2.8 or less. When the matrix aromatic polycarbonate has a narrow molecular weight distribution such as Mw / Mn <2.3, the melt flowability of the matrix aromatic polycarbonate becomes extremely poor. Also, 2.8 <Mw / Mn
In the case where the molecular weight distribution is wide as described above, the base aromatic polycarbonate already contains a large amount of the low molecular weight portion, so that the impact resistance is greatly reduced by the addition of the dicarbonate.

The amount of dicarbonate added to the aromatic polycarbonate is about 0.2 to 1.0% by weight. The suitable range of its composition cannot be uniquely determined by the weight ratio because it varies depending on the molecular weight and molecular weight distribution of the parent aromatic polycarbonate, but the peak height of dicarbonate in the GPC chromatogram of the obtained aromatic polycarbonate is high. Is 2% of the height of the main peak
It is preferably 8% or less. When it is less than 2%, the effect of improving the melt fluidity of the aromatic polycarbonate becomes slightly small, and when it exceeds 8%, the impact resistance of the parent aromatic polycarbonate tends to be slightly decreased.

The method of mixing the aromatic polycarbonate and the dicarbonate may be mixing in a solution, mixing in a powder or in a molten state. In the case of mixing with a solution, a solvent used in the interfacial polycondensation method can be used. For example, aliphatic chlorinated compounds such as dichloromethane, chloroform, 1,2-dichloroethane, 1,2-dichloroethylene, trichloroethane, tetrachloroethane, dichloropropane and the like, or a mixture thereof, particularly preferred is dichloromethane. The concentration of the solution to be mixed can be arbitrarily selected within the range of 10 to 30% by weight of the aromatic polycarbonate solution and 5 to 45% by weight of the dicarbonate solution. In the case of the method of the present invention, since the amount of the solution of the dicarbonate is about 0.04 to 6.00% by weight with respect to the amount of the solution of the aromatic polycarbonate, the amount of the solvent to be handled is extremely high. In addition, since the solution of dicarbonate does not increase in viscosity and has a low viscosity, uniform mixing can be easily achieved by stirring with a normal stirring blade or with a line mixer. As a powder mixing method,
There is a method using a ribbon blender, a tangler blender, a Henschel mixer, or the like. As a mixing method in a molten state, there is a method of melting and kneading at 250 ° C. to 270 ° C. with a Banbury mixer, a single screw extruder, a twin screw extruder or the like, and mixing in a pellet form.

The aromatic polycarbonate of the method of the present invention is
Mechanical properties are controlled only by the mother aromatic polycarbonate, and uniform mixing of the mother aromatic polycarbonate and the dicarbonate is easy, so the target physical properties are given and their reproducibility is excellent. . And, by achieving the desired improvement in melt flowability, precision parts with complicated shapes and thin products, which were difficult to injection-mold until now, and large, thick products, etc.
It has become possible to perform molding under temperature conditions that do not cause product deterioration.

Further, in the method of the present invention, known additives for aromatic polycarbonates are used for the purpose of imparting thermal stability, light resistance, weather resistance, flame retardancy and other properties during processing of aromatic polycarbonates. Can be added. These known additives include processing and heat stabilizers,
Examples thereof include antioxidants, ultraviolet absorbers, release agents, organic halogen compounds, alkali metal sulfonates, glass fibers, glass beads, barium sulfate and TiO2.

[0027]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to the following examples. The values of the number average molecular weight (Mn) and the weight average molecular weight (Mw) used in the examples are G manufactured by Showa Denko KK
It was calculated in terms of polystyrene from a chromatogram obtained by measuring with a chloroform solvent using a polystyrene gel column by PC SYSTEM-11 and using an RI detector, and the polydispersity index (Mw / Mn) was calculated from the value. ) Was asked. Further, the height of the peak of dicarbonate and the height of the main peak are calculated from the intensity of the slice data of the portion corresponding to the top of each peak. Melt index value (hereinafter abbreviated as "MI")
Is a temperature measured by a melt indexer manufactured by Toyo Seiki Co., Ltd. 2
80 ° C, load 2.16kg, length 8.000 ± 0.0
The weight of the polymer extruded from a steel die having a small hole of 25 mm and an inner diameter of 2.095 ± 0.005 mm in 10 minutes was measured. For the Izod impact test, the Izod impact tester manufactured by Toyo Seiki Co., Ltd. was used.
It was measured according to K 7110.

Production Example (Production of Dicarbonate) 706.0 g (2.00 mol) of bischloroformate of bisphenol A and 600.0 g (4.00 mol) of p-tert-butylphenol were added to a reaction vessel equipped with a stirrer.
Then, 2500 g of an organic solvent was charged, and the mixture was stirred and dissolved at room temperature. Next, triethylamine 505.0 g (5.0
0 mol) was mixed with 700 g of an organic solvent and diluted, and this was supplied to the reaction tank at a rate of 20.1 g / min.
The reaction was carried out by stirring at 30 ° C. After the supply of the triethylamine solution was completed, stirring was continued for another 1 hour for aging. Then, the obtained organic solvent solution was mixed with hydrochloric acid and stirred to remove residual triethylamine. After separating this, the organic solvent solution was further mixed with pure water and stirred to extract and remove triethylamine hydrochloride in the aqueous phase. The organic solvent solution was distilled off to obtain a crude product of dicarbonate of the type in which bischloroformate of bisphenol A was sealed at both ends with p-tertiarybutylphenol.
This crude product was mixed with 8000 g of n-hexane, heated and stirred at a reflux temperature to dissolve it, and then slowly cooled to crystallize dicarbonate to obtain a purified product. After the purified product was dried, the quality was verified by elemental analysis. As a result, C% is a theoretical value of 7
76.48% vs. 6.53%, H% theoretical value 6.94
% Was 6.98%.

Example 1 8406 g (36.87 mol) of bisphenol A and p-tert-butylphenol 17 as a molecular weight regulator
4.759 g (1.165 mol), triethylamine 5.994 g (0.05935 mol), caustic soda 42
77 g (106.93 mol) and 16.794 g of sodium hydrosulfite were dissolved in 57.06 kg of water to prepare an aqueous mixture having a total weight of 69.94 kg. 129.56 g each of this mixture, phosgene, and an organic solvent
/ Min, 7.638 g (0.07715 mol) / min, 12
It was introduced into the first tank reactor at 7.37 g / min. The reaction mixture is discharged from this tank reactor at 264.57 g / min. The residence time was 20 minutes. The reaction mixture continuously discharged is supplied to a second tank reactor by using a pipe, polymerization is carried out for a residence time of 40 minutes, and further, the reaction mixture is supplied to a third tank reactor and retained. Polymerization was carried out for 40 minutes. The reaction mixture continuously discharged from the third tank reactor was immediately separated into liquids and neutralized with hydrochloric acid. The obtained organic phase was washed with pure water until the electrolyte was exhausted.
This continuous operation was carried out for 9 hours, and the molecular weight of the obtained aromatic polycarbonate was analyzed hourly. Mn = 2
0700-20900, Mw = 51500-52000
And Mw / Mn = 2.48 to 2.50. Then, 56000 g of this purified aromatic polycarbonate organic solvent solution (polymer concentration: 12.5% by weight)
Then, 46.7 g of a separately prepared organic solvent solution having a dicarbonate concentration of 30% by weight was placed in a mixing tank and stirred and mixed. The organic solvent was evaporated from the organic solvent solution containing this aromatic polycarbonate to obtain a solid aromatic polycarbonate. GPC of the obtained polymer
Peak height of dicarbonate relative to main chromatographic peak height in measurement [PH] (%), M
Table 1 shows the I and Izod impact test values.

Examples 2 and 3 The same operation as in Example 1 was repeated except that the organic solvent solution of dicarbonate to be mixed was 46.7 g, and in Example 2 it was 116.7 g and in Example 3 233. The procedure was changed to 3 g to obtain a dicarbonate mixture of aromatic polycarbonate. Table 1 shows the height of the dicarbonate peak [PH] (%), the MI, and the Izod impact test value with respect to the height of the main peak of the chromatogram in the GPC measurement of the obtained polymer.

Comparative Example 1 Table 1 shows the test results of the aromatic polycarbonate obtained in Example 1 by distilling off the solvent without adding and mixing the organic solvent solution of dicarbonate.

[0032]

[Table 1] Table 1 Mw = 51500 to 52000, Mw /
Addition of Mn = 2.48 to 2.50 to PC

Examples 4 to 6 The same procedure as in Example 1 was repeated to obtain 174.759 g (1.16 g) of p-tertiarybutylphenol, which is a molecular weight modifier.
5 mol) was used, but 122.973 g (0.
820 mol). When the molecular weight of the obtained aromatic polycarbonate was analyzed hourly, Mn = 2
7600-27800, Mw = 69300-69800
And Mw / Mn = 2.49 to 2.53. Then, 56000 g of this purified aromatic polycarbonate organic solvent solution (polymer concentration: 12.5% by weight)
And a separately prepared organic solvent solution having a dicarbonate concentration of 30% by weight was 46.7 g in Example 4 and 1 in Example 5.
16.7 g, and 233.3 g in Example 6 were charged in a mixing tank and stirred and mixed. The organic solvent was evaporated from the organic solvent solution containing this aromatic polycarbonate to obtain a solid aromatic polycarbonate. Table 2 shows the peak height [PH] (%) of the dicarbonate, the MI, and the Izod impact test value with respect to the height of the main peak of the chromatogram in the GPC measurement of the obtained polymer.

Comparative Example 2 Table 2 shows the test results of the aromatic polycarbonate obtained by distilling off the solvent in Example 4 without adding and mixing the organic solvent solution of dicarbonate.

[0035]

[Table 2] Table 2 Mw = 69300 to 69800, Mw /
Addition of Mn = 2.49 to 2.53 to PC

[0036]

EFFECT OF THE INVENTION By the method of the present invention, it is possible to obtain the target impact resistance with good reproducibility and to obtain an aromatic polycarbonate suitable for injection molding, which has improved melt flowability while maintaining its excellent properties. It becomes possible to easily obtain a precision molded product, a molded product having a thin wall thickness, and a large molded product having a thick wall wall, by utilizing the characteristics of the aromatic polycarbonate.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Yukiko Mori 30 Asamu-cho, Omuta-shi, Fukuoka Within Mitsui Toatsu Chemical Co., Ltd. In-house (72) Inventor Masahiro Ota 30 Asmuta-cho, Omuta-shi, Fukuoka Mitsui Toatsu Chemical Co., Ltd.

Claims (2)

[Claims] 1. A molecular weight distribution of Mw / Mn = 2.3-2.
Improvement in melt fluidity obtained by adding to the aromatic polycarbonate represented by 8 a compound in which a terminal is completely sealed with a carbonate from one molecule of an aromatic dihydroxy compound which is a constitutional unit of the aromatic polycarbonate. Aromatic polycarbonate. 2. The gel permeation chromatography chromatogram of the obtained aromatic polycarbonate, wherein the height of the peak of dicarbonate is 2% or more and 8% or less with respect to the height of the main peak. The aromatic polycarbonate described.