JPH06211977A - Production of hydroxyl-terminated aromatic polycarbonate resin - Google Patents

Abstract

PURPOSE:To obtain an arom. polycarbonate resin having phenolic hydroxyl groups at the molecular terminals by subjecting a dihydric phenol and phosgene to interfacial polymn. and stopping the reaction by adding ammonia in the polymn. step when the attempted mol.wt. is reached. CONSTITUTION:This poIycarbonate resin is obtd. by subjecting a dihydric phenol and phosgene to interfacial polymn. and stopping the reaction by adding ammonia at the polymn. step when the attempted mol.wt. is reached. Ammonia is added when the viscosity-average mol.wt. of the resulting polycarbonate reaches 5,000-100,000. The amt. of ammonia added is 0.2-50mol, pref. 1-10mol, based on 1mol of remaining chloroformate groups.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing an aromatic polycarbonate resin having a phenolic hydroxyl group at a terminal.

[0002]

2. Description of the Related Art When phosgene and a dihydric phenol are condensed in water and a water-immiscible organic solvent system to produce an aromatic polycarbonate, the presence of a monohydric phenol as an end-capping agent causes the formation of an arbitrary molecular weight. It is generally known that polycarbonates can be produced (Schnell, "Chemistry and Physics of Polycarbonates" p. 39 John Willie Publishing 1964). Most of the terminal groups of the polycarbonate resin obtained by such a method are the residues of the monohydric phenol used as the terminating agent, and thus are not usually reactive.

On the other hand, a polycarbonate having a functional group capable of reacting at the terminal has attracted attention as a raw material for a block copolymer, and a method for producing a polycarbonate having a highly reactive hydroxyl group at the terminal has been desired. Also in the field of polymer alloys, it is known that thermal stability and impact resistance can be improved by introducing a reactive polycarbonate into polyamide, polyester, etc. (Noriaki Shimaoka, Industrial Materials 1990, 38 , 38). Norio Hosaka, Plastic Swage 1991, 147.).

However, regarding the method for producing a polycarbonate having a hydroxyl group at the terminal, a method for producing an oligomer for maintaining the pH at 10 to 12 (Japanese Patent Publication No. 2-29064) and a terminal stopper having two hydroxyl groups having different reactivity are used. Method (JP-A-2-245022), method of transesterification with aliphatic diols (JP-A-61-272230),
Protect the hydroxyl group with a terminal terminator that serves as the protective group,
Method of deprotection after completion of polymerization (Japanese Patent Laid-Open No. 63-30803)
4) and the like are known, but it is difficult to produce a high-molecular weight polycarbonate by the method of controlling the pH,
The method using a protecting group is not practical because the manufacturing process becomes complicated. The method of introducing an aliphatic hydroxyl group also poses a problem that the physical properties such as heat resistance and strength are deteriorated and the reactivity during copolymerization is deteriorated. That is, a method for producing an aromatic polycarbonate having a desired molecular weight having a hydroxyl group at a terminal in one step has not been known.

[0005]

SUMMARY OF THE INVENTION The present invention provides about 20
The present invention provides a method for producing an aromatic polycarbonate having an arbitrary degree of polymerization of 400 to 400 mer and having a phenolic hydroxyl group at the terminal.

[0006]

Means for Solving the Problems As a result of intensive investigations by the present inventors, when a polycarbonate is produced by an interfacial polymerization method using phosgene and a dihydric phenol as raw materials, any polymerization having a viscosity average molecular weight of 5,000 to 100,000 is performed. It was found that a polycarbonate with a high degree of polymerization having a hydroxyl group at the terminal can be obtained by the method of adding ammonia when the temperature reaches a certain level and stopping the polymerization.

That is, the gist of the present invention is that when an aromatic polycarbonate resin is produced from a dihydric phenol and phosgene by an interfacial polymerization method, ammonia is added at the time when a desired molecular weight is reached in the polymerization process to carry out the polymerization. A method for producing an aromatic polycarbonate resin having a hydroxyl group at the terminal is characterized by stopping the reaction. Hereinafter, the present invention will be described in detail. In the present invention, an interfacial polymerization method of polycondensing dihydric phenol and phosgene in water and a water-immiscible organic solvent is used.

Examples of the water-immiscible organic solvent used in the present invention include aromatic hydrocarbons such as benzene, toluene and xylene, aromatic ethers such as anisole and diphenyl ether, and halogenated aromatic hydrocarbons such as chlorobenzene and dichlorobenzene. Dichloromethane, chloroform, 1,
Halogenated hydrocarbons such as 2-dichloroethane and 1,1,2-trichloroethylene can be mentioned, with dichloromethane being most preferred. The divalent phenolic compound that is a raw material monomer is usually represented by the general formula (1)
The bisphenols represented by are used.

[0009]

[Chemical 1]

In the above general formula, X ¹ and X ² are hydrogen, halogen or a lower alkyl group, and Z is a linear or branched alkylene group having 9 or less carbon atoms or O, S, CO, SO.
Means a bond represented by ₂ . Typical compounds are 4,4'-dihydroxybiphenyl, bis (4-hydroxyphenyl) methane, bis (4-hydroxyphenyl) ether, bis (4-hydroxyphenyl) ketone, bis (4-hydroxyphenyl) sulfide, Bis (4-hydroxyphenyl) sulfone, 2,2-bis (4-hydroxyphenyl) propane, 1,1-bis (4-hydroxyphenyl) cyclohexane and hydrogenation of these aromatic rings by halogenation or methylation of a methyl group or the like. The compound substituted by the hydrogen group is mentioned.

In the first step of the present invention, a water-immiscible organic solvent and phosgene are introduced into a caustic aqueous solution in which a divalent phenolic compound is dissolved to obtain a polycarbonate oligomer having a low degree of polymerization. The obtained polycarbonate oligomer having a chloroformate terminal can have a higher molecular weight by polycondensation. It is also possible to continuously carry out the production of the oligomer and the subsequent polymerization, and it is also possible to once separate the organic solvent solution of the oligomer from the aqueous phase, and then add a new alkaline aqueous solution to proceed with the polymerization.

During the polymerization, the caustic concentration of the aqueous phase is 0.
It is adjusted to 1 to 10 N, preferably 0.5 to 5 N. If the concentration of caustic is too low, the polymerization will not proceed, and if it is too high, the hydrolysis of the polymer will proceed. Also,
Excess caustic is used so that 0.1 to 0.5 normal caustic remains after all the terminal groups of the oligomer have reacted with caustic. Considering the liquid separation property and the size of the reaction tank, the amount of the aqueous phase is preferably 10 to 50% by volume with respect to the organic phase.

The reaction temperature and pressure are not particularly limited, but it is desirable to carry out the reaction at a temperature of 0 to 100 ° C. considering the reaction rate of the polymerization. In order to control the molecular weight to reach, polymerization is usually carried out without a catalyst, but it is also possible to use a surface-active catalyst to accelerate the reaction rate. As the surface-active catalyst, tertiary amines such as trimethylamine, triethylamine, tri (n-butyl) amine, pyridine, N, N-diethylaniline and ammonium salts such as benzyltrimethylammonium chloride can be considered, but they are easily available and are easy to handle. The easy triethylamine is preferred.

In the present invention, when the viscosity average molecular weight of the polymer reaches the desired degree of polymerization of 5,000 to 100,000, ammonia is added to obtain an aromatic polycarbonate having a hydroxyl group at the terminal without changing the molecular weight. . The amount of ammonia used is 0.2 to 50 times molar equivalent, preferably equimolar to 10 times molar equivalent, based on the remaining chloroformate group. The method of adding ammonia is not particularly limited, and it may be added in the form of gas, but it is preferable to add it as an aqueous solution in terms of handling.

After adding ammonia, it is preferable to continue stirring for 5 minutes to 5 hours to form hydroxyl groups until the reaction is completed. At the end of the reaction, the aqueous phase is separated off and acid is added until the residual alkali is completely neutralized and acidic. Examples of the acid used at this time include inorganic acids such as hydrochloric acid, sulfuric acid, nitric acid and phosphoric acid, and organic acids such as acetic acid and oxalic acid.

Isolation of the polymer is carried out according to conventional methods. That is, after repeatedly washing the organic phase with demineralized water, the solvent is removed to obtain a polymer solid. When it is desired to control the amount of terminal hydroxyl groups, a monofunctional phenol compound such as 4- (t-butyl) phenol can be used as a terminal stopper. In this case, after the monofunctional phenol is added during the polymerization, ammonia is added when the target molecular weight is reached.

By the method of the present invention, it is possible to obtain a polycarbonate resin having a phenolic hydroxyl group at the terminal with a desired molecular weight and by a simple method.

[0018]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples without departing from the gist thereof. The properties of the polymers obtained in the following examples were analyzed by the following methods.

1. Viscosity average molecular weight The polymer was dissolved in a dichloromethane solvent to a concentration of about 6 g / l, and the viscosity was measured using a Ubbelohde viscometer in a constant temperature water bath at 20 ° C. The molecular weight conversion of viscosity was in accordance with Schnell's formula shown below.

[0020]

[Equation 1] Mv = 51400 × [η] ^1.205

2. Quantification of terminal chloroformate group The polymer was dissolved in a dichloromethane solvent to a concentration of 0.05 to 5 g / l according to the residual amount of the chloroformate group, and 4- (nitrobenzyl) pyridine was added at a concentration of 0.8 g / l. To add color so that the color develops. The absorbance of the obtained colored solution at 440 nm was measured to be 0.2 to 20 μm.
Using the factor obtained from the absorbance of eq / l phenyl chloroformate standard solution, it was converted to the amount of chloroformate groups.

3. Quantification of terminal hydroxyl group Depending on the residual amount of the terminal group, the polymer is dissolved in a dichloromethane solvent of about 1 v% acetic acid at a concentration of 0.05 to 5 g / l, and titanium tetrachloride is added to a concentration of about 1 v%. To do. The absorbance at 480 nm of the obtained colored solution was measured and converted into the amount of hydroxyl groups using the factor obtained from the absorbance of the bisphenol A standard solution of 20 to 120 μeq / l.

4. Molecular weight distribution Mw / Mn The polymer was dissolved in a tetrahydrofuran solvent at a concentration of 5 g / dl, and the gel permeation chromatograph (4
It was determined in terms of monodisperse polystyrene using a TSK gel column and eluent tetrahydrofuran) in a constant temperature bath at 0 ° C. 5. Nuclear magnetic resonance spectrum ( ¹ H-NMR) A sample prepared by dissolving about 30 mg of a polymer in about 5 ml of deuterated chloroform was placed in a measuring tube having an inner diameter of 5 mm, and JEOL α-40 was used.
The measurement was performed at 0 (400 MHz, 32 scans). δ
Tetramethylsilane was used as the standard for the value and was set to 0 ppm.

6. Infrared spectrum (IR) JASCO FT / IR-7000 was used to prepare a dichloromethane solution having a polymer concentration of about 5 wt% and N having a gap of 0.2 mm.
It was placed in an aCl cell and the measurement was carried out at 400 to 4000 cm ^-1 .

(Preparation of Oligomer) 2,2- (4-hydroxyphenyl) propane 20.3 g / hour, sodium hydrosulfite 23 mg / hour, sodium hydroxide 7.3 g / hour, demineralized water 124 g / hour. Inner volume 10
After introducing into a 0 ml stirring tank and stirring and dissolving at 35 ° C., phosgene 9.9 g / hour and dichloromethane 67.2 g in a tubular reactor having an inner diameter of 6 mm and a length of 125 cm lined with polytetrafluoroethylene (PTFE). / Introduced with time. The resulting oligomer solution was separated and the lower organic phase was used for polymerization. The oligomer concentration was 27 wt%, and it had a terminal chloroformate group of 1985 μeq / g and a terminal hydroxyl group of 998 μeq / g.

(Embodiment 1) Three-stage two-blade blade (d
/D=0.5, the lower two stages are scraped by 45 °) into a 2 liter separable flask equipped with the above oligomer solution 9
52 ml and dichloromethane 588 ml were added to dilute the oligomer concentration to 16% by weight. Set the inner temperature of the flask to 3
Keeping at 0 ℃, 2.5N aqueous caustic soda solution 460m
1 was added, and the mixture was stirred at 1000 rpm for 2 hours. (At this point, sampling was performed and 35% by weight of hydrochloric acid was added to terminate the polymerization reaction, and the molecular weight and the terminal group concentration of this product were measured. The results were taken as values before addition of ammonia.)

Thereafter, a 28% by weight aqueous ammonia solution was added to 4 parts.
0 ml was added, and stirring was continued for another 30 minutes, and then about 70 ml of 35 wt% hydrochloric acid was added. Stop stirring after 20 minutes,
The solution was allowed to stand still for partitioning. Approximately 600 ml by extracting the lower organic phase
Demineralized water was added and the mixture was stirred and washed. This operation was repeated twice, and the neutral organic phase was stirred at 70 ° C. using a small kneader equipped with a distillation column to remove the solvent and pulverize.
The obtained powder was dried in a ventilation dryer at 120 ° C for 12 hours. The dried powder has a viscosity average molecular weight of 16400, a terminal chloroformate group of 0.01 μeq / g and a hydroxyl group of 172 μeq / g, and a molecular weight distribution (Mw / M
n) was 2.88. ^{In 1} H-NMR, a peak of hydroxyl group appeared at a δ value of 4.8 ppm, and in IR, absorption of a carbonyl group was confirmed at 1775 cm ^-1 . The viscosity average molecular weight before addition of ammonia was 16000, the terminal chloroformate group was 198 μeq / g, and the terminal hydroxyl group was 5 μeq / g. The results are shown in Table 1.

(Examples 2 to 3) The reaction operation was carried out according to Example 1. However, the polymerization time until the addition of aqueous ammonia was extended to 3 hours (Example-2) and 3 hours 30 minutes (Example-3), and the viscosity average molecular weights reached were 220 and 220, respectively.
Changed to 00, 27,000. Table of physical properties of the produced polymer
Summarized in 1.

(Examples 4 to 5) When polymerization was carried out according to Example 1, the amount of the aqueous ammonia solution added was 4 ml.
When the amount was changed to (Example-4) and 2 ml (Example-5), the amount of hydroxyl groups produced was also decreased. The analytical values of the produced polymer are summarized in Table 1. (Example-6) After polymerization was carried out in the same manner as in Example-1, the amount of 35% by weight hydrochloric acid added at the end of the reaction was 150 m.
changed to l. No change was observed in the amount of terminal hydroxyl groups even if excess hydrochloric acid was added. The polymer analysis values are summarized in Table 1.

(Comparative Example-1) In a separable flask having an internal volume of 1 liter and equipped with 6 turbine blades, 476 ml of the above oligomer solution and 293 ml of dichloromethane were added to dilute the concentration to 16% by weight. Set the inner temperature of the flask to 3
230m of 2.5N caustic soda solution kept at 0 ℃
1 was added and stirred at 1200 rpm. After 40 minutes, 0.53 g of trimethylamine was added, and the stirring was continued for another 20 minutes. Then, about 30 ml of 35 wt% hydrochloric acid was added and the mixture was stirred for 5 minutes, and then the stirring was stopped. After the stationary separation, the lower organic phase was taken out, about 300 ml of demineralized water was added, and the mixture was stirred and washed for 10 minutes. After repeating this operation twice, the neutralized organic phase was placed in a small kneader equipped with a distillation column at 70 ° C. and 70 rp.
Milled by stirring at m. The obtained polycarbonate powder was dried for 12 hours in a ventilation dryer at 120 ° C. The powder had a viscosity average molecular weight of 26400, a terminal chloroformate group of 0.24 μeq / g and a hydroxyl group of 107 μeq / g.
had g. The viscosity average molecular weight before addition of trimethylamine was 8200, and the terminal chloroformate group 55
It was 9 μeq / g and hydroxyl group was 35 μeq / g.

[0031]

[Table 1]

[0032]

According to the method of the present invention, it becomes possible to produce a polycarbonate having a desired molecular weight having a hydroxyl group at the terminal by a relatively simple method. Polycarbonates having hydroxyl groups at the ends are highly reactive and are useful as raw materials for polymer alloys such as block copolymers.

Front page continued (72) Inventor Kenichi Sugimoto 1-1 Kurosaki Shiroishi, Hachimansai-ku, Kitakyushu City Mitsubishi Kasei Co., Ltd. Kurosaki Plant

Claims (2)

[Claims] 1. When producing an aromatic polycarbonate resin from a dihydric phenol and phosgene by an interfacial polymerization method, ammonia is added to stop the polymerization reaction at the time when a desired molecular weight is reached in the polymerization process. A method for producing an aromatic polycarbonate resin having a hydroxyl group at a terminal. 2. The method for producing an aromatic polycarbonate resin according to claim 1, wherein ammonia is added when the viscosity average molecular weight of the polycarbonate reaches 5,000 to 100,000.