JP3116386B2 - Aromatic polycarbonate resin with excellent thermal stability - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates is characterized in that the nitrogen atom content in the molecular chain is under 3ppm or less, and a chlorine atom amount based on the chloroformate group at the molecular chain terminals is 2ppm or less, aromatic It relates to a polycarbonate resin. More specifically, the present invention relates to an aromatic polycarbonate resin having excellent heat stability during molding.

[0002]

2. Description of the Related Art Aromatic polycarbonate resins have been used in a wide variety of applications such as extruded products such as sheets and films, large containers and the like, or injection molded products because of their transparency and excellent mechanical properties.

[0003]

However, when a sheet or film is manufactured by extrusion molding, the roll is contaminated by decomposition products caused by the polycarbonate resin during molding, and contaminants on the roll are contaminated on the sheet or film. It may be transcribed and lower the commercial value. In order to prevent transfer of contaminants to sheets and films, it was necessary to keep the rolls clean.To do so, it was necessary to frequently wipe the rolls, but such operations were extremely complicated and improved. Was required.

On the other hand, also in injection molding and blow molding using a mold, a decomposition product of a polycarbonate resin decomposed due to a high temperature at the time of molding adheres to the surface of the mold, and the adhered material is transferred to the surface of the molded product, and the product is removed. There was a problem that the quality deteriorated. Further, the transfer of the deposits to the molded product also leads to a decrease in the product yield. In order to prevent a decrease in product quality and to improve the yield, it is necessary to frequently clean the mold and keep the mold clean. Was sought. In addition, since the gas generated by the decomposition is present between the mold and the molded product, spots or haze-like patterns appear on the surface of the molded product, thereby impairing the aesthetic appearance of the product and lowering its commercial value. There was also. These problems can be improved a little by adding a release agent or the like, but this is not a fundamental solution, and it has been a problem to find an effective solution.

[0005]

Means for Solving the Problems The inventors of the present invention have made it possible to prevent contamination of products due to roll contamination during sheet or film molding, to prevent deterioration of product aesthetics due to mold contamination during injection molding or blow molding or generated gas, and As a result of examining the frequency of cleaning of rolls and molds due to dirt, such dirt on the rolls and molds is due to the insufficient thermal stability of the polycarbonate resin used, and the polymerization incorporated at the molecular chain terminals. Polycarbonate in which the amount of nitrogen atoms based on the catalyst and the amount of chloroformate groups remaining during polymerization (that is, the amount of chlorine atoms based on the chloroformate groups) are not more than a certain amount,
It has been found that the thermal stability has been dramatically improved, and the contamination of rolls and molds has been significantly improved.

That is, the gist of the present invention is to provide an aqueous solution of an alkali metal hydroxide of a dihydroxydiaryl compound and phosgene in the presence of an inert organic solvent by an interfacial polycondensation reaction to produce a viscosity average molecular weight of 18,000 to 40,000.
A) The aromatic polycarbonate resin according to (1), wherein the amount of nitrogen atoms incorporated in the molecular chain is 3 ppm or less, and (2) the amount of chlorine atoms based on the chloroformate group at the terminal of the molecular chain is 2 ppm or less. In an aromatic polycarbonate resin having excellent heat stability during molding.

Hereinafter, the present invention will be described in detail. The aromatic polycarbonate resin of the present invention is obtained by an interfacial polycondensation reaction from an aqueous alkali metal hydroxide of a dihydroxydiaryl compound and phosgene in the presence of an inert organic solvent. The interfacial polycondensation reaction is well known as a method for producing an aromatic polycarbonate resin, and is specifically carried out in the present invention by the following method. That is, first, after dissolving the dihydroxydiaryl compound in an aqueous alkali metal hydroxide solution,
Reaction with phosgene in the presence of an inert organic solvent to form a low molecular weight polycarbonate oligomer having a chloroformate group at the molecular end, and then adding a molecular weight regulator and a tertiary amine as a polymerization catalyst to the oligomer And polymerize under stirring. Further, at the time of polymerization, if necessary, an aqueous alkali metal hydroxide solution or an aqueous alkali metal salt of a dihydroxydiaryl compound and a free aqueous alkali metal hydroxide solution can be added. Further, after the obtained organic solvent solution of the low molecular weight polycarbonate oligomer is separated from the aqueous phase, if necessary, an aqueous alkali metal hydroxide solution or an alkali metal salt of a dihydroxydiaryl compound and a free alkali metal hydroxide are newly added. An aqueous solution can also be added.

The dihydroxydiaryl compounds used in the present invention include bis (4-hydroxyphenyl) methane, 1,1-bis (4-hydroxyphenyl) ethane, and 2,2-bis (4-hydroxyphenyl). )
Propane (hereinafter referred to as bisphenol A), 2,2-
Bis (4-hydroxyphenyl) butane, 2,2-bis (4-hydroxyphenyl) octane, 1,1-bis (4-hydroxyphenyl) phenylethane, 2,2-
Bis (4-hydroxy-3-methylphenyl) propane, 2,2-bis (4-hydroxy-3,5-dimethylphenyl) propane, 2,2-bis (4-hydroxy-
3-tert-butylphenyl) propane, 2,2-bis (4
-Hydroxy-3-bromophenyl) propane, 2,2
-Bis (4-hydroxy-3,5-dibromophenyl)
Bis (hydroxyaryl) alkanes such as propane, 2,2-bis (4-hydroxy-3,5-dichlorophenyl) propane, 1,1-bis (4-hydroxyphenyl) cyclopentane, 1,1-bis ( Bis (hydroxyaryl) cycloalkanes such as 4-hydroxyphenyl) cyclohexane and 1,1-bis (4-hydroxy-3-methylphenyl) cyclohexane;
Dihydroxydiaryl ethers such as 4'-dihydroxydiphenylether and 4,4'-dihydroxy-3,3'-dimethyldiphenylether;4,4'-
Dihydroxydiaryl sulfides such as dihydroxydiphenyl sulfide and 4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfide; 4,4'-
Dihydroxydiarylsulfoxides such as dihydroxydiphenylsulfoxide and 4,4'-dihydroxy-3,3'-dimethyldiphenylsulfoxide;
And dihydroxydiarylsulfones such as 4'-dihydroxydiphenylsulfone and 4,4'-dihydroxy-3,3'-dimethyldiphenylsulfone. These are used singly or as a mixture of two or more, but phloroglysin, 1,1,1-tris (4-hydroxyphenyl) ethane, α, α ′, α ″ -tris (4
-Hydroxyphenyl) -1,3,5-triisopropylbenzene may be used in combination with an appropriate amount of a trifunctional compound to form a branched polycarbonate.

These dihydroxydiaryl compounds are used after being dissolved and dispersed in an aqueous solution of an alkali metal hydroxide. Examples of the alkali metal hydroxide include sodium hydroxide (caustic soda), potassium hydroxide (caustic potash) and the like, with sodium hydroxide being particularly preferred. The ratio (molar ratio) of the dihydroxydiaryl compound and the alkali metal oxide to be dissolved and dispersed is preferably 1: 1.5 to 3.5, and the concentration of the dihydroxydiaryl compound in the aqueous solution is preferably 5 to 15% by weight. In order to prevent oxidative coloring of the dihydroxydiaryl compound, a reducing agent such as sodium sulfite or sodium dithionite may be added as an antioxidant.

The inert organic solvent used in the present invention is
An organic solvent that is substantially insoluble in water and inert to the reaction and that dissolves polycarbonate. Specific examples include chlorinated aliphatic hydrocarbons such as methylene chloride, chloroform, dichloroethane, and tetrachloroethane, and chlorinated aromatic hydrocarbons such as chlorobenzene, dichlorobenzene, and chlorotoluene. Also,
These and dioxane, tetrahydrofuran, toluene,
Mixtures with organic solvents such as cyclohexane and n-heptane can be used, but methylene chloride is preferred industrially.

In the present invention, a monofunctional compound is generally used as a molecular weight regulator in order to regulate the molecular weight of the produced polycarbonate resin. Specific examples include monophenols such as phenol, p-cresol and p-tert-butylphenol, and their aromatic monovalent carboxylic acid chlorides such as chloroformate, benzoic acid chloride and p-toluic acid chloride.

As the tertiary amine which is a polymerization catalyst to be added, triethylamine, tri-n-propylamine,
Tri-n-butylamine, diethylaminopyridine and the like can be mentioned, but triethylamine is industrially desirable from the viewpoint of easy removal in the washing step. The addition amount of the tertiary amine is based on the dihydroxydiaryl compound used.
0.001 to 1.0 mol%, preferably 0.01 to 0.
5 mol%. If the amount is less than 0.001 mol%, the effect of improving the liquid separation property is small, and if it exceeds 1.0 mol%, although the effect of improving the liquid separation property is obtained, a great deal of labor is required for extracting and removing the polymerization catalyst in the washing step. Necessary and not preferred.

The aromatic polycarbonate resin of the present invention comprises:
Viscosity average molecular weight 18,000 to 40,000, preferably
20,000 to 30,000. Here, the viscosity average molecular weight (Mv) is a value calculated from the value of the specific viscosity η _sp measured at 20 ° C. using a 0.6 g / dl methylene chloride solution of the polymer according to the following equation. It is. η _sp /C=[η](1+0.28η _sp ) [η] = 1.23 × 10 ^-5 Mv ^0.83 (C: concentration g / dl in solution, [η]: intrinsic viscosity]

The aromatic polycarbonate resin of the present invention comprises:
The nitrogen atom content incorporated into the molecular chain is 3 ppm or less,
It is preferably 1.5 ppm or less, and the chlorine atom content based on the chloroformate group remaining at the molecular chain terminal is 2 ppm.
The polycarbonate resin of the present invention, which satisfies these conditions at the same time, exhibits high thermal stability and has excellent physical properties such that roll stains and mold stains are hardly generated. It has.

The aromatic polycarbonate resin of the present invention comprises:
As long as it satisfies the above conditions, any one obtained by any production method has the effect of the present invention,
Simultaneously reducing the amount of terminal nitrogen and the amount of residual chlorine is not easily achievable. The chloroformate group is
As the polymerization proceeds, it is consumed by the reaction represented by the following formula (A) to give a high molecular weight polycarbonate.
A tertiary amine is used as a polymerization catalyst in order to alkali-hydrolyze the excess chloroformate group to participate again in the polymerization. However, it is considered that a part of the tertiary amine is incorporated into the terminal by a reaction represented by the following formula (B). . ——OCOCl + NR ₃ → ——OCONR ₂ + RCl— (B) (R is a hydrocarbon group) The amount of nitrogen incorporated into the terminal varies depending on the polymerization conditions. That is, when performing interfacial polycondensation in a stirring tank, the amount of tertiary amine added as a catalyst increases as the amount of addition of the tertiary amine increases, and the amount of tertiary amine increases as the addition of tertiary amine increases at the beginning of polymerization The amount increases. One way to reduce the amount of terminal incorporation is to reduce the amount of tertiary amine added at the beginning of polymerization.On the other hand, to effectively decompose the excess amount of chloroformate groups, Of tertiary amine must be added.

As described above, it is very difficult to simultaneously reduce the amount of terminal nitrogen taken in and the amount of residual chlorine in a stirring and mixing tank generally used for the polymerization of polycarbonate. In particular, it was extremely difficult to reduce the level to the level of the present invention (the terminal nitrogen content was 3 ppm or less and the residual chlorine content was 2 ppm or less). The amount of nitrogen atoms incorporated in the molecular chain and the amount of chlorine bonded to the molecular chain, i.e., the reduction of chlorine atoms based on the terminal chloroformate group can be reduced by various methods. In which the tertiary amine is added in the highly emulsified state. That is, in the polymer production process using the interfacial polycondensation reaction,
This is a method in which a tertiary amine is added at the time when a highly emulsified state in which an average droplet diameter of a dispersed aqueous phase in an inert organic solvent as a polymerization solvent is 10 μm or less. This method will be described below.

As a method of emulsifying the reaction mixture of the polycondensation reaction, there are a method of high-speed stirring, a method of adding an aqueous alkali solution with stirring, and the like. It is also possible to emulsify by using a simple stirrer (paddle, propeller, turbine, chi-type blade, etc.) at a high rotation speed, but as a device for obtaining a high emulsified state as described above, There are high-speed stirrers such as homogenizers and homomixers, colloid mills, orifice mixers, flow jet mixers, ultrasonic emulsifiers, etc., and when these are used, finer droplets than those obtained with a simple stirrer are used. This is particularly effective because a highly emulsified state having a diameter can be obtained. Of course,
In the present invention, the emulsification method is not particularly limited as long as the emulsified state can be obtained such that the diameter of the dispersed aqueous phase droplet satisfies the above-mentioned rule, and the method using these high-speed stirrers or the above method is used. A method using a simple stirrer or a combination thereof can be appropriately used.

The highly emulsified state in the present invention is defined as
In a water-in-oil emulsified state formed from an organic solvent solution of the low molecular weight polycarbonate oligomer and an aqueous solution of an alkali metal hydroxide, the average droplet diameter of the aqueous phase as a disperse phase is measured by, for example, laser diffraction particle size distribution measurement. 1 when measured using an instrument (manufactured by Shimadzu Corporation, SALD1100)
It refers to a state of 0 μm or less. To bring the reaction mixture into an emulsified state, the aqueous phase is removed from the reaction mixture after the phosgenation reaction by standing or centrifugation, and water and fresh water are added to the obtained organic solvent solution of the low-molecular-weight polycarbonate oligomer. An alkali may be added and used, or a reaction mixture after the phosgenation reaction containing the low-molecular-weight polycarbonate oligomer may be used as it is. In carrying out the polycondensation reaction in an emulsified state, in order to maintain a good emulsified state, the ratio of the aqueous phase to the organic phase in the reaction mixture in the polycondensation reaction is usually the volume ratio of the organic phase to the organic phase and the aqueous phase. It is preferably 0.05 to 1.0. The polycarbonate concentration in the organic solvent is 8
-30% by weight, preferably 10-25% by weight.

In carrying out the polymerization reaction, the organic solvent solution of the low molecular weight polycarbonate oligomer obtained by the phosgenation reaction may be further diluted by adding an organic solvent (diluting solvent). The diluting solvent is selected from the same range as the above-mentioned organic solvent. In the present invention, in order to suppress the reaction between the tertiary amine which is a polymerization catalyst and the chloroformate group of the low molecular weight polycarbonate oligomer,
Tertiary amines need to be added after a particular high degree of emulsification has been formed. When the tertiary amine is added in a state where the droplet diameter of the aqueous phase is larger than 10 microns, the tertiary amine reacts with the oligomer or the chloroformate group remaining below the intermediate molecular weight polymer whose molecular weight is increasing. It is not preferable because it is taken into the polymer terminal and causes roll contamination and mold contamination during molding at high temperatures.

Furthermore, in the highly emulsified state of the present invention, the amount of residual chloroformate in the solid oligomer is 6%.
It is preferably at most 00 × 10 ⁻⁶ eq / g. If the emulsification is insufficient, this value is usually 600 × 10 ⁻⁶ eq / g,
Further, although it exceeds 700 × 10 ⁻⁶ eq / g, when the tertiary amine is added in such a state, not only the amount of the tertiary amine incorporated into the polycarbonate terminal increases, but also
When the amount of the catalyst increases, the molecular weight may not reach a predetermined value. On the other hand, when the droplet diameter is in an emulsified state having an average diameter of 10 μm or less, the residual chloroformate concentration may be 1 depending on the concentration of the alkaline aqueous solution, the amount of load energy at the time of emulsification, and the like.
In some cases, the tertiary amine may be added in such a state, although it may be as low as 00 × 10 ^{−6 to} 300 × 10 ⁻⁶ eq / g.

The state of emulsification after passing through the emulsifier changes depending on the magnitude of the energy given by the emulsifier.
On the other hand, it is greatly affected by the concentration of the oligomer solution, the concentration of the alkali metal hydroxide in the aqueous alkali solution, the ratio of the aqueous phase to the organic phase, and the like. These conditions work in combination with each other, but the preferred value of the concentration of the organic solvent solution of the oligomer (including the diluting solvent) supplied to the emulsifier is 8 to 30% by weight in terms of the produced polycarbonate. Preferably it is in the range of 10 to 25% by weight. The concentration of the alkali in the alkaline aqueous solution is determined in relation to the aqueous phase ratio,
The concentration of the supplied aqueous alkali solution is preferably 2 to 15% by weight, more preferably 3 to 10% by weight. If the concentration is too low, the emulsified state is not easily stabilized, which is not preferable. The ratio of the aqueous phase and the organic phase is an important factor that affects the emulsified state. However, since the aqueous phase must be a dispersed phase, the aqueous phase is 0.05 to 1.0 ( Volume ratio), more preferably 0.1 to 0.8.
It is.

In the method of the present invention, the tertiary amine can be added by any method after the reaction mixture having reached a predetermined emulsified state is removed from the emulsifier.
For example, adding a tertiary amine immediately after leaving the emulsifier,
Alternatively, the reaction mixture in a highly emulsified state after leaving the emulsifier can be added after being retained in a stirring tank or the like for an appropriate time, and the latter method is more preferable. When the chloroformate concentration in the low-molecular polycarbonate oligomer supplied to the emulsifier is originally high, the emulsified state is close to the emulsifier outlet even if the droplet diameter of the dispersed aqueous phase is 10 μm or less. Sometimes the chloroformate concentration is too high. When the tertiary amine is added in such a state, the amount of nitrogen taken into the terminal may increase. However, with an appropriate residence time, the chloroformate can be reduced to 600 × 10 ⁻⁶ eq / g or less. And the diameter of the dispersed aqueous phase droplet is 10 microns or less, which is more preferable.

The method of mixing and stirring during the addition of the tertiary amine is not particularly limited, and may be added under high emulsification conditions during the polymerization. In order to further improve the liquid separation property in the above, it is desirable to mix the tertiary amine under more gentle mixing and stirring conditions than in the polymerization. After the addition of the tertiary amine, the stirring is continued as it is, and the reaction is terminated when the target molecular weight is reached. After completion of the reaction, the aqueous phase of the reaction mixture contains a large amount of tertiary amines and the like in the alkali metal hydroxide, carbonate, chloride, and organic phase. The reaction mixture as it is, or after dilution with an organic solvent or water, is separated into an aqueous phase and an organic phase by static separation or centrifugation. Thereafter, the tertiary amine and alkali components contained in the organic phase are extracted and removed with an acidic aqueous solution of hydrochloric acid, phosphoric acid, etc., and further thoroughly washed with water until the organic phase is free of impurities. The organic solvent is removed by a conventional method to obtain a solid high molecular weight aromatic polycarbonate.

In the present invention, the polymerization reaction involving the chloroformate group is achieved by using the aqueous phase as the dispersed phase in interfacial polycondensation and achieving an emulsified state in which the dispersed aqueous phase droplet diameter is smaller than 10 microns. Significantly accelerated, increase in molecular weight,
And the consumption of the chloroformate group is carried out smoothly. Furthermore, when the tertiary amine is added in a highly emulsified state in which the aqueous phase as the dispersed phase is smaller than 10 microns, the polymerization reaction is further promoted and the aqueous phase after reaching the target molecular weight,
The separation and separation of the organic phase is significantly improved. Also, when a tertiary amine is added in a highly emulsified state, very little tertiary amine is incorporated at the molecular terminal.

That is, the polymerization reaction involving the chloroformate group is accelerated by a highly emulsified state because the involved reaction species are present in both the organic phase and the aqueous phase. Although accelerated, the reaction between the tertiary amine and the chloroformate group is not greatly affected by the emulsified state because both the tertiary amine and the chloroformate are present in the organic phase. Therefore, it is considered that while the residual chloroformate group was extremely reduced, the amount of nitrogen taken into the terminal was drastically reduced. Without the addition of a tertiary amine, the liquid separation properties of the polymerization reaction solution are extremely poor, and even if the viscosity of the organic phase is reduced by the addition of methylene chloride, the liquid separation of both phases will be performed within the industrially practical time. do not do.

Control of the amount of terminal nitrogen and the amount of residual chloroformate groups can be achieved by the following means. That is, the terminal nitrogen amount is obtained by adding a tertiary amine after the aqueous phase droplet diameter reaches a highly emulsified state smaller than 10 microns, so that the terminal nitrogen amount taken into the polycarbonate chain after the polymerization is completed. Usually it does not exceed 2 ppm. In some cases, a small amount of a tertiary amine is added to an oligomer obtained from an alkali metal salt of diphenol and phosgene to further react the remaining diphenol without being phosgenated. Terminal nitrogen is taken in. At this time, the amount of nitrogen taken in is 1
If it is around ppm, the amount of terminal nitrogen in the polycarbonate that has reached the target molecular weight after the above-mentioned polymerization reaction is usually 3 pp.
m. On the other hand, the chloroformate group decreases with time. The manner of reduction depends on the conditions of emulsification, reaction temperature, reaction conditions such as the amount of tertiary amine, and the like. Therefore, the reaction may be stopped when the amount of chlorine based on the residual chloroformate group becomes less than 2 ppm. The molding material of the present invention includes various known additives, for example, release agents such as paraffin, fatty acid and fatty acid ester, various phosphorus-based heat stabilizers, hydrolysis inhibitors such as epoxy compounds, hindered phenols and the like. May be contained.

[0027]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to Production Examples and Examples, but the present invention is not limited thereto unless it exceeds the gist thereof. All percentages in the production examples are percentages by weight unless otherwise specified. Each measured value in the examples was obtained by the following method. (A) Viscosity average molecular weight (Mv) 20% using a 0.6 g / dl methylene chloride solution of a polymer.
From η _sp measured at ° C., it was calculated from the equation η _sp /C=[η](1+0.28 η _sp ) [η] = 1.23 × 10 ⁻⁵ Mv ^0.83 .

(B) Measurement of the concentration of the chloroformate group in the oligomer and the high molecular weight polycarbonate Pretreatment (for the reaction mixture in an emulsified state) About 30 g of the reaction mixture leaving the emulsifier or the reaction tank was prepared in advance with 50 ml of a 1N aqueous hydrochloric acid solution and methylene chloride 1.
20 ml was taken in a separating funnel and shaken quickly (using KM-SHAKER, manufactured by Iwaki Co.) to neutralize the alkali in the reaction mixture and stop the progress of the reaction. At this time, it was confirmed that the aqueous phase was acidic. After standing separation (about 5 minutes), the methylene chloride phase was separated, 50 ml of demineralized water was added, and the mixture was shaken for 5 minutes and washed. After standing and separating,
Demineralized water was added again, and the washing was repeated until the aqueous phase became neutral. The methylene chloride solution containing the oligomer or polymer thus obtained is placed on a hot plate (60
° C) and heated for 30 minutes to remove most of the methylene chloride, and further dried with a ventilation dryer for 60 minutes to obtain a solid content. The oligomer was subjected to analysis as it was,
In the case of a polymer, it was further dried at 120 ° C. for 10 hours by vacuum drying.

2. Analysis of the amount of chlorine atoms derived from unreacted chloroformate groups remaining at the terminals of the polycarbonate (i) Measurement of the concentration of chloroformate groups It can be determined by measurement. When the concentration of the chloroformate group is 1 × 10 ⁻⁴ eq / g or more based on the solid content, the measurement is performed by this measurement method. When the amount of the residual chloroformate group is 1 × 10 ⁻⁴ eq / g to the solid content or less,
Since this measurement method lacks accuracy, analysis is performed according to the method for measuring the amount of trace chlorine shown in (ii). Dissolve 1.0 g of solid content in 20 ml of methylene chloride or take 20 ml of a reaction solution (methylene chloride solution) diluted to 4 to 5%, add 0.1 ml of aniline under stirring with a stirrer, and react with chloroformate. Then, 10 ml of pure water was added and the mixture was stirred, aniline hydrochloride was extracted into the aqueous phase, and titration was performed with 0.2 ^N NaOH using phenolphthalein as an indicator to quantify the amount of chloroformate group in the sample. This was converted to chlorine atom weight.

(Ii) Analysis of trace amount of chlorine About 1 g of the granular polycarbonate obtained in the production example was precisely weighed,
20 ml of methylene chloride was added to dissolve. This is 4- (p
2 ml of a 1 wt% methylene chloride solution of (-nitrobenzyl) pyridine (Wako Pure Chemical Industries, Ltd., special grade) was added for color development, and the absorbance at a wavelength of 440 nm was measured using a spectrophotometer (Model 330, manufactured by Hitachi, Ltd.). Separately, the extinction coefficient was determined using a solution of phenylchloroformate in methylene chloride (ε ₄₄₀ =
2.5 × 10 ⁴ liter / mol · cm), the amount of trace chlorine derived from the chloroformate group in the sample was determined. The lower limit of quantification was 0.2 ppm in terms of chlorine amount relative to solids.

(C) Measurement of the amount of nitrogen incorporated in the molecular chains of the oligomer and the high molecular weight polycarbonate. Using a solid obtained by the pretreatment shown in (b) above or about 20 mg of the produced granular polycarbonate, it was measured by a total nitrogen analyzer (TN-10) manufactured by Mitsubishi Chemical Corporation. (D) Measurement of the average droplet size of the dispersed aqueous phase in the emulsified state. Take the emulsion on a glass slide without dilution
A cover glass was placed with a spacer of 0μ interposed therebetween to obtain a sample. The average droplet diameter was determined using a laser diffraction particle size distribution analyzer (SALD1100, manufactured by Shimadzu Corporation). (E) Yellowness index It was measured using SM-5-CH manufactured by Suga Test Instruments Co., Ltd.

(F) Evaluation of roll contamination during sheet forming A manifold type die having a lip width of 450 mm was mounted on a 65 mmφ extractor (manufactured by Osaka Seiki Co., Ltd.).
Polycarbonate resin granules were supplied from a hopper.
(Extruder conditions: cylinder temperature 260 ° -290 ° C., die temperature 280 ° C., degree of vent vacuum 750 mmHg, screw rotation speed 26 rpm). The molten polycarbonate extruded from the die was formed by passing through a three-stage roll having an oil circulation device inside a 200 mmφ × 550 mm width. (Roll temperature: upper stage 190 ° C., middle stage 150 ° C., lower stage 130 ° C.) At this time, dirt (cloudiness and glossiness) of each roll was visually observed and evaluated. The evaluation was performed at regular intervals (hrs) after the start of film formation.

(G) Evaluation of wrinkles of molded products in injection molding Kneading: Using a 40 mm vent type (Isuzu Kako Co., Ltd.), cylinder set temperature 260-280 ° C., screw rotation speed 80 rpm, vent vacuum degree -750 mmHg went. Molding: molding machine-Nissei Plastics Co., Ltd., FS-600 Cylinder temperature -285 → 290 → 250 → 270
(Nozzle → Hopper) (Resin temperature 310 to 315 ° C) Mold temperature-fixed 100 ° C / movable 97 ° C Injection / cooling time-8/3 (second), (cycle 18 to 2)
0 sec) Injection speed-99% Die: 100 mm square x 3 mmt sheet type Evaluation: Poor appearance (wrinkles) while changing injection pressure
Was evaluated. In addition, in order to clarify the determination of wrinkle strength, A JEOL vacuum evaporation machine (TEE-4X) was used.
1 was deposited. The state of wrinkles on the surface of the injection molded product was classified into the following five types. (Note that gas components and the like are likely to accumulate at both ends of the molded product and wrinkle patterns are likely to occur.) 0: No wrinkles are observed. 1: wrinkles are slightly observed at the end of the molded product. 2: Wrinkles of about 1 to 2 cm are observed at both ends of the molded product. 3: Wrinkles of about 3 to 4 cm are observed at both ends of the molded product. 4: Wrinkles are observed on the entire surface up to the center of the molded product.

Reference Example 1 (Preparation of low molecular weight polycarbonate oligomer used in Production Examples)
Seed materials: a) aqueous sodium hydroxide solution of bisphenol A (solution containing 15.61 parts by weight of bisphenol A dissolved in 100 parts by weight of a 5.65% by weight aqueous solution of caustic soda), b) methylene chloride and c) It has an inlet for phosgene, and the outlet is 60
6mmφ (1m wall thickness) connected to a liter stirring tank
m), into a 16 m long Teflon tube, methylene chloride 53 kg / hr (approximately 41.7 l / hr), bisphenol A caustic soda aqueous solution 118.4 kg / hr (approximately 1
15 liters / hr) and at the same time 7.80 kg / hr of phosgene. The reaction mixture exiting the Teflon tube was introduced into a 60-liter stirring tank (effective volume up to the overflow pipe: 60 liters, two stages of paddle blades, paddle diameter / tanner diameter ratio 0.45, with baffle plate), and The temperature was externally cooled and maintained at 30 ° C.

A methylene chloride solution having a P-tert-butylphenol (P-TBP) concentration of 24% by weight was simultaneously supplied to the stirring tank at a rate of 1.27 kg / hr. The reaction mixture coming out of the stirring tank was guided to a separation tank and allowed to stand to separate an aqueous phase and a methylene chloride solution of the oligomer. The amount of the obtained methylene chloride solution of the oligomer is 74 kg / hr per unit time,
After running for 10 hours, 725 kg of a methylene chloride solution was obtained. The obtained oligomer solution is placed on a hot plate (6
(0 ° C.) for 30 minutes to remove methylene chloride, and further dried for 1 hour in a ventilation dryer (60 ° C.) to obtain a solid content. Next, the chloroformate group concentration was measured according to the method for measuring the amount of terminal chloroformate group in 2 (i) of the above-mentioned measurement method (b). As a result, the concentration of the chloroformate group in the methylene chloride solution of the oligomer before removing the methylene chloride was 0.31N.

Production Example 1 Two emulsifiers (“TK Pipeline Homomixer 2S” manufactured by Tokushu Kika Kogyo Co., Ltd., equipped with one low-viscosity turbine) were connected, and the second reaction liquid outlet was continuous. The following reaction was carried out using the equipment guided to the two stirred tanks. The two stirring tanks are as follows. First polymerization tank: 180 liter capacity, stirring speed 200 rpm Second polymerization tank: 53 liter capacity, stirring speed 300 rpm Two emulsifiers were adjusted to 6000 rpm, and the first emulsifier was obtained in Reference Example 1 Chloroformate group (hereinafter, referred to as
62 l / hr (80 kg / hr) of an oligomer solution having a concentration of 0.31 N, 33 l / hr (44 kg / hr) of methylene chloride, and 2 l of a 1.2 N sodium hydroxide solution
When supplied at 7 liters / hr (28 kg / hr), the CF concentration at the outlet of each emulsifier was 650 × 10 ^-6 eq / g per oligomer solid (the outlet of the first emulsifier) and 40 CF, respectively.
It was 0 × 10 ⁻⁶ eq / g (outlet of the second emulsifier). The reaction mixture exiting the second emulsifier is led to a first polymerization tank, where a 2% by weight aqueous solution of triethylamine is 0.4 kg / hr.
Was supplied continuously. The reaction mixture overflowing the first polymerization tank was led to the second polymerization tank and then to the washing / separation step.

Eight hours after starting the supply to the emulsifier,
After 12 hours, the reaction mixture was collected from the outlet of the second polymerization tank, and methylene chloride was added to reduce the solids concentration in the organic phase to 8%.
Adjusted to% by weight. Shaker (Iwaki, KM
(SHAKER) for 5 minutes, and then immersed in a thermostat at 30 ° C., and the time required for separating the organic phase and the aqueous phase was measured. The time when the interface started to separate was 50 minutes and 52 minutes, respectively, and the time when the interface was completely separated was 80 minutes and 78 minutes. After 8 hours, the reaction mixture exiting the second polymerization tank was adjusted to 8% by weight with methylene chloride, the aqueous phase was separated, washed with a 0.2N aqueous hydrochloric acid solution to remove free triethylamine, and further demineralized water. And washed three times. A part of the thus-purified methylene chloride solution of the polycarbonate was cast on a stainless steel pad coated with Teflon to form a dried film in a dryer. After the film was sufficiently dried in a vacuum dryer, the amount of nitrogen taken in was measured. The amount of nitrogen was 0.9. The viscosity average molecular weight was 27,700.

On the other hand, the purified methylene chloride solution of the polycarbonate is introduced together with warm water of about 60 ° C. into a stirring tank equipped with an external circulation type wet pulverizer.
The mixture was pulverized while evaporating methylene chloride while maintaining the temperature. A part of the pulverized product was taken out from the circulation line of the wet pulverizer, and was continuously guided to a centrifugal separator to obtain a granular polycarbonate. Granular polycarbonate is vacuum dried (12
It was dried at 0 ° C. and 5 mmHg) to obtain a powder having a methylene chloride concentration of less than 50 ppm. The viscosity average molecular weight of this powder pair is 277
00, the amount of incorporated terminal nitrogen was 0.9 ppm.
Further, the amount of residual chlorine remaining at the terminal of the polycarbonate was 0.5 ppm.

Production Examples 2 and 3 and Comparative Production Example 1 Two "pipeline homomixers" in Example 1
The polymerization was carried out by changing the number of revolutions and the amount of a 2% by weight aqueous triethylamine solution added to the first polymerization tank as shown in Table 1. The time required for interfacial separation, the amount of nitrogen in the polymer,
Table 1 shows the results of the residual chlorine amount and the like.

Production Example 4, Comparative Production Examples 2, 3 Using only the first unit of the pipeline homomixer (second bypass), changing the emulsifier rotation speed, the aqueous sodium hydroxide solution concentration and the supply amount, and The same operation as 1 was performed. The time required for interfacial separation, the amount of nitrogen taken in, the amount of residual chlorine, and the like were measured. The results are shown in Table 2.

Comparative Production Example 4 Two units of “TK pipeline homomixer” were removed from the apparatus used in Example 1, and the two polymerization tanks of Example 1 were transferred to the first polymerization tank and the second polymerization tank shown in Example 1. Exact amounts of the oligomer solution, methylene chloride, and caustic soda solution were fed. Polymerization was carried out in exactly the same manner as in Production Example 1, except that a 2% by weight aqueous triethylamine solution was fed to the first polymerization tank at 0.04 kg / hr and to the second polymerization tank at 0.36 kg / hr. Further, it was made into a granular material. The viscosity average molecular weight of the obtained polycarbonate was 27,500, and the nitrogen content in the polymer was 8.0 ppm. Further, the amount of chlorine based on the chloroformate group remaining at the end of the polycarbonate in the granular material was 9.0 ppm. After starting the supply, 8 hours and 12 hours after diluting the polymerization solution to 8% by weight, shaking for 5 minutes, the time until the interface starts to separate was 50 minutes and 50 minutes, respectively, and the interface was completely separated. The time was 80 minutes and 75 minutes.

Comparative Production Example 5 The same operation as in Comparative Production Example 4 was performed except that the number of revolutions of the first polymerization tank was set to 400 rpm. The results are shown in Table 3. Comparative Production Example 6 Except that the rotation speed of each of the first and second polymerization tanks was 100 rpm, and the amount of triethylamine added was 0.04 kg / hr,
It carried out like Comparative Production Example 1. The results are shown in Table 3.

Production Example 5 By exactly the same operation as in Reference Example 1, an aqueous solution of bisphenol A in sodium hydroxide, methylene chloride and phosgene were reacted.
When the reaction solution exiting the Teflon tube was introduced into the 60-liter stirring tank shown in Reference Example 1, a mixture of triethylamine and 2.27 kg / hr of a methylene chloride solution having a P-TBP concentration of 24 wt% was added.
% Aqueous solution was supplied at a rate of 0.4 kg / hr, and the other treatments were performed in exactly the same manner as in Reference Example 1. As a result, 730 kg of a methylene chloride solution of the oligomer having a chloroformate concentration of 0.25 N in the solution was obtained by operation for 10 hrs. The liquid separation property between the methylene chloride solution of the oligomer and the aqueous phase was better than in Reference Example 1, and sodium bicarbonate, which was not observed in Reference Example 1, was formed in the aqueous phase. The amount of terminal nitrogen in the oligomer was 1.5 ppm based on the solid content. Using this oligomer, the same operation as in Production Example 4 was performed. The results are shown in Table 3.

Example 1 Using the polycarbonate resin granules obtained in Production Example 1,
The sheet was formed by the method shown in (g) above, and the change in the glossiness of the roll surface was visually observed over time. The dirt on each roll was observed, and the following evaluation was performed. ：: The initial gloss is maintained. Δ: The roll surface starts to be clouded. ×: The roll has completely lost gloss due to the clouding. As shown in Table 4, the roll surface shows the initial gloss even after 50 hours. Had been maintained.

Examples 2 to 5, Comparative Examples 1 to 6 Sheets were formed in the same manner as in Example 1, and the change in gloss of each roll was followed over time. The results are shown in Tables 4 to 6.

[Table 1]

[Table 2]

[Table 3]

[Table 4]

[Table 5]

[Table 6]

Reference Example 2 The supply amount of methylene chloride having a P-tert-butylphenol concentration of 24% by weight described in Reference Example 1 was 1.55 kg /
Except for hr, the same operation as in Reference Example 1 was performed. 1
The amount of methylene chloride in the oligomer obtained by the operation for 0 hours was 730 kg, and the chloroformate concentration was 0.3 kg.
0N. Production Examples 6, 7, 8 and Comparative Production Example 7 Except that the methylene chloride solution of the oligomer was changed to that obtained in Reference Example 2, the viscosity average molecular weight was 22500 and the incorporated terminal nitrogen was obtained in exactly the same manner as in Production Example 1. 0.7pp
m, a powder having a residual chlorine amount of 0.6 ppm derived from the chloroformate remaining at the terminal was obtained (Production Example 6). The results shown in Table 7 were obtained in the same manner as in Production Examples 2 and 3 and Comparative Example 1 with respect to the rotation speed of the pipeline homomixer and the amount of the triethylamine aqueous solution (Production Examples 7 and 8 and Comparative Production Example 7). . Using the oligomers obtained in Production Example 9, Comparative Production Examples 8 and 9 and Reference Example 2, the same operations as in Production Example 4 and Comparative Production Examples 2 and 3 were performed, and the results shown in Tables 7 and 8 were obtained.

Comparative Production Examples 10 and 11 Using the oligomer of Reference Example 2, the result of Comparative Production Example 10 was obtained by the same operation as Comparative Production Example 4, and the result of Comparative Production Example 11 was obtained by the same operation as the Comparative Production Example. Was. The results are shown in Table 8. Example 6 Using the polycarbonate granules obtained in Production Example 6, injection molding was performed by the method shown in (g) above, and wrinkles on the surface of the molded product were measured. The results are shown in Table 9. Examples 7 to 10 and Comparative Examples 7 to 11 The same injection molding as in Example 6 was carried out, and the results were shown in Tables 9-1.
0.

[Table 7]

[Table 8]

[Table 9]

[Table 10]

[0048]

Industrial Applicability The aromatic polycarbonate resin of the present invention is excellent in thermal stability at the time of molding, prevents contamination of products due to roll contamination at the time of molding of sheets and films, and prevents metal contamination during injection molding and blow molding. Prevention of deterioration of product aesthetics due to mold contamination or generated gas, and reduction of frequency of cleaning rolls and molds due to contamination are achieved.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-57-185320 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08G 64/00-64/42

Claims (1)

(57) [Claims] 1. An aromatic polycarbonate resin having a viscosity average molecular weight of 18,000 to 40,000 produced by an interfacial polycondensation reaction from an aqueous alkali metal hydroxide of a dihydroxydiaryl compound and phosgene in the presence of an inert organic solvent. (B) thermal stability during molding, characterized in that the amount of nitrogen atoms incorporated into the molecular chain is 3 ppm or less, and (b) the amount of chlorine atoms based on the chloroformate group at the terminal of the molecular chain is 2 ppm or less. Aromatic polycarbonate resin with excellent properties.