JP3195848B2 - Method for producing polycarbonate copolymer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a process for producing a polycarbonate copolymer containing siloxane units and having a high molecular weight, which is useful as a material for industrial materials in general, and particularly as a material for electronic and electrical equipment parts.

[0002]

2. Description of the Related Art Polycarbonate is used as an industrial material in various application fields because of its excellent transparency and heat resistance. In particular, bisphenol A type polycarbonate is known to be useful as a binder resin in a photosensitive layer of an electrophotographic photosensitive member because of its good compatibility with a charge transporting substance. However, as the field of application expands, there is a demand for a characteristic having higher performance than that of bisphenol A type polycarbonate which has been conventionally produced using bisphenol A or the like as a raw material. In response to such a demand, for example, in order to improve abrasion resistance, development of a polycarbonate copolymer using a dihydroxy compound containing a silicon atom as a comonomer in addition to bisphenols as a raw material is being advanced.

[0003] Such a polycarbonate copolymer is disclosed in European Patent Application No. 0 005087 (1).
992), a dihydroxy compound having a long chain of dimethylsiloxane unit was dissolved in an aqueous sodium hydroxide solution together with a bisphenol such as 2,2-bis (4-hydroxyphenyl) propane (bisphenol A), and phosgene gas was dissolved in triethylamine as a catalyst. Is introduced into a monomer solution to cause a reaction. However, in such a production method, since the solubility of the dihydroxy compound having a dimethylsiloxane unit in water is small and a uniform liquid phase cannot be formed, a polycarbonate copolymer having a sufficiently high molecular weight cannot be obtained. .

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to solve the problems in the production of polycarbonate copolymers having siloxane units found in the above prior art, and to easily and stably produce high molecular weight polycarbonate copolymers. An object of the present invention is to provide a manufacturing method that can be manufactured in a uniform manner.

[0005]

Means for Solving the Problems The present inventors have conducted intensive studies to solve the above problems, and as a result, when copolymerizing bisphenols with a dihydroxy compound having a siloxane unit, the bisphenols were previously converted into bisphenols. After producing an oligomer, they found that a high-molecular-weight polycarbonate copolymer can be obtained by interfacial polycondensation using the oligomer and a dihydroxy compound having a siloxane unit as a homogeneous mixed solution. The invention has been completed.

That is, the present invention provides a compound represented by the following general formula (I):

[0007]

Embedded image [Wherein, R ¹ and R ² are each independently a halogen atom, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 5 to 12 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 12 carbon atoms. A and b are each independently an integer of 0 to 4, Y is a single bond, -O-, -CO-, -S-, -SO
—, —SO ₂ —, —CR ³ R ⁴ — (where R ³ and R ⁴ are each independently a hydrogen atom, a trifluoromethyl group, an alkyl group having 1 to 12 carbon atoms, a cyclo group having 5 to 12 carbon atoms) An alkyl group or a substituted or unsubstituted aryl group having 6 to 12 carbon atoms), a 1,1-cycloalkylidene group having 5 to 8 carbon atoms, or an α, ω-alkylene group having 2 to 12 carbon atoms. A dihydric phenol (I) represented by the following general formula (II)

[0008]

Embedded image (Wherein, R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ and R ¹⁰ are each independently a hydrogen atom, an alkyl group having 1 to 12 carbon atoms or a substituted or unsubstituted aryl having 6 to 12 carbon atoms. And R is
¹¹ and R ¹² are each independently a halogen atom, carbon number 1 to 6
Is an alkyl group or a substituted or unsubstituted aryl group having 6 to 12 carbon atoms, c and d are each independently an integer of 0 to 4, and X is a substituted or unsubstituted alkylene group having 1 to 6 carbon atoms. Wherein n is an integer of 1 to 6, p is a natural number, q is 0 or a natural number, and p + q is a natural number less than 100. ) Represented by the dihydric phenol (I)
In producing a polycarbonate copolymer by reacting I) with an ester-forming compound, the dihydric phenol (I) has a terminal chloroformate group by the reaction of the ester-forming compound and has a degree of polymerization. 2
And then forming the oligomer and the dihydric phenol (II) with a solution of the oligomer and the dihydric phenol (II) in a water-insoluble organic solvent. An object of the present invention is to provide a method for producing a polycarbonate copolymer, which comprises interfacial polycondensation in a mixed solution with an aqueous alkali solution.

The dihydric phenol (I) represented by the general formula (I) used in the method of the present invention includes, for example, bis (4-hydroxyphenyl) methane, 1,1-bis (4
-Hydroxyphenyl) ethane, 1,2-bis (4-hydroxyphenyl) ethane, 2,2-bis (4-hydroxyphenyl) propane, 2,2-bis (3-methyl-
4-hydroxyphenyl) butane, 2,2-bis (4-
(Hydroxyphenyl) butane, 2,2-bis (4-hydroxyphenyl) octane, 4,4-bis (4-hydroxyphenyl) heptane, 4,4′-dihydroxytetraphenylmethane, 1,1-bis (4-hydroxy Phenyl) -1-phenylethane, 1,1-bis (4-hydroxyphenyl) -1-phenylmethane, bis (4-hydroxyphenyl) ether, bis (4-hydroxyphenyl) sulfide, bis (4-hydroxyphenyl)
Sulfone, 1,1-bis (4-hydroxyphenyl) cyclopentane, 1,1-bis (4-hydroxyphenyl) cyclohexane, 2,2-bis (3-methyl-4-
Hydroxyphenyl) propane, 2- (3-methyl-4)
-Hydroxyphenyl) -2- (4-hydroxyphenyl) -1-phenylethane, bis (3-methyl-4-hydroxyphenyl) sulfide, bis (3-methyl-4)
-Hydroxyphenyl) sulfone, bis (3-methyl-
4-hydroxyphenyl) methane, 1,1-bis (3-
Methyl-4-hydroxyphenyl) cyclohexane,
2,2-bis (2-methyl-4-hydroxyphenyl)
Propane, 1,1-bis (2-butyl-4-hydroxy-5-methylphenyl) butane, 1,1-bis (2-t
tert-butyl-4-hydroxy-3-methylphenyl) ethane, 1,1-bis (2-tert-butyl-4)
-Hydroxy-5-methylphenyl) propane, 1,1
-Bis (2-tert-butyl-4-hydroxy-5-
Methylphenyl) butane, 1,1-bis (2-tert
-Butyl-4-hydroxy-5-methylphenyl) isobutane, 1,1-bis (2-tert-butyl-4-hydroxy-5-methylphenyl) heptane, 1,1-bis (2-tert-butyl-4) -Hydroxy-5-methylphenyl) -1-phenylmethane, 1,1-bis (2
-Tert-amyl-4-hydroxy-5-methylphenyl) butane, bis (3-chloro-4-hydroxyphenyl) methane, bis (3,5-dibromo-4-hydroxyphenyl) methane, 2,2-bis ( 3-chloro-4-
Hydroxyphenyl) propane, 2,2-bis (3-fluoro-4-hydroxyphenyl) propane, 2,2-
Bis (3-bromo-4-hydroxyphenyl) propane, 2,2-bis (3,5-difluoro-4-hydroxyphenyl) propane, 2,2-bis (3,5-dichloro-4-hydroxyphenyl) propane , 2,2-bis (3,5-dibromo-4-hydroxyphenyl) propane, 2,2-bis (3-bromo-4-hydroxy-5-
Chlorophenyl) propane, 2,2-bis (3,5-dichloro-4-hydroxyphenyl) butane, 2,2-bis (3,5-dibromo-4-hydroxyphenyl) butane, 1-phenyl-1,1- Bis (3-fluoro-4-
Hydroxyphenyl) ethane, bis (3-fluoro-4)
-Hydroxyphenyl) ether, 1,1-bis (3-
Cyclohexyl-4-hydroxyphenyl) cyclohexane, 4,4'-dihydroxybiphenyl, 4,4'-
Dihydroxy-3,3'-dimethylbiphenyl, 4,
4'-dihydroxy-2,2'-dimethylbiphenyl,
4,4'-dihydroxy-3,3'-dicyclohexylbiphenyl, 3,3'-difluoro-4,4'-dihydroxybiphenyl, 2,2-bis (4-hydroxyphenyl) hexafluoropropane, 2,2-bis (3-phenyl-4-hydroxyphenyl) propane, 1,1-
Bis (3-phenyl-4-hydroxyphenyl) cyclohexane, bis (3-phenyl-4-hydroxyphenyl) sulfone, 4,4'-dihydroxybenzophenone and the like can be mentioned.

Particularly preferred are 2,2-bis (4-hydroxyphenyl) propane, 4,4'-dihydroxytetraphenylmethane, 1,1-bis (4-hydroxyphenyl) -1-phenylethane, bis (4 -Hydroxyphenyl) sulfone, 1,1-bis (4-hydroxyphenyl) cyclohexane, 2,2-bis (3-methyl-
4-hydroxyphenyl) propane, 4,4'-dihydroxybiphenyl and 2,2-bis (3-phenyl-4
-Hydroxyphenyl) propane is used. One of these dihydric phenols (I) may be used alone, or two or more of them may be used in combination.

P + q representing the degree of polymerization of the polysiloxane unit in the dihydric phenol (II) represented by the general formula (II)
Is related to the strength, transparency and adhesion of the polycarbonate copolymer, so it is difficult to unconditionally define it. However, it is generally less than 100, preferably less than 80. If it exceeds 100, the transparency of the polycarbonate copolymer decreases.

As the dihydric phenol (II), for example, the following compounds are preferably used.

[0013]

Embedded image In the method of the present invention, only one type of dihydric phenol (II) may be used, or two or more types may be used.

The ratio of the dihydric phenol (I) to the dihydric phenol (II) is not particularly limited, but usually, the molar ratio of the dihydric phenol (I) to the dihydric phenol (II), (II) ) / [(I) + (II)], 0.0
It is preferably in the range of 0001 to 0.3, preferably 0.0001 to 0.2. When the molar ratio of dihydric phenol (II) is less than 0.00001, the mechanical strength of the obtained polycarbonate copolymer may be insufficient. On the other hand, when the molar ratio exceeds 0.3, the surface hardness of the obtained polycarbonate copolymer may be insufficient.

Further, other comonomers other than the above-mentioned dihydric phenols (I) and (II) can be used in combination as long as they do not hinder the method of the present invention.

In the method of the present invention, first, a compound having a terminal chloroformate group and a degree of polymerization of 2 to 4 is used as a main component by reacting a dihydric phenol (I) with a carbonate-forming compound. An oligomer of dihydric phenol (I) is formed.

In producing the dihydric phenol (I) oligomer, the entire amount of the dihydric phenol (I) used in the method of the present invention may be converted into the oligomer at a time, or a part of the oligomer may be used as a post-addition monomer. It may be added as a reaction raw material to a subsequent interfacial polycondensation reaction. The post-addition monomer is added for promptly proceeding the subsequent polycondensation reaction, and it is not necessary to add it when unnecessary.

Although there is no particular limitation on the type of the oligomer formation reaction, it is generally preferable to carry out the reaction in a solvent in the presence of an acid binder.

The proportion of the carbonate-forming compound used is as follows:
What is necessary is just to adjust suitably considering the stoichiometric ratio (equivalent) of reaction. When a gaseous carbonate-forming compound such as phosgene is used, a method of blowing the compound into the reaction system can be suitably employed.

Examples of the acid binder include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide;
An alkali metal carbonate such as sodium carbonate or potassium carbonate, an organic base such as pyridine, or a mixture thereof is used.

The proportion of the acid binder to be used may be appropriately determined in consideration of the stoichiometric ratio (equivalent) of the reaction in the same manner as described above. Specifically, it is preferred to use 2 equivalents or a slight excess of the acid binder relative to the number of moles of the dihydric phenol (I) used for forming the oligomer (usually 1 mole corresponds to 2 equivalents). .

As the solvent, a solvent inert to various reactions such as those used in the production of known polycarbonates may be used alone or as a mixed solvent. Representative examples include, for example, hydrocarbon solvents such as xylene, and halogenated hydrocarbon solvents such as methylene chloride and chlorobenzene. In particular, halogenated hydrocarbon solvents such as methylene chloride are preferably used. The interfacial polycondensation reaction may be performed using two types of solvents that do not mix with each other.

The reaction pressure for the formation of the oligomer is not particularly limited and may be any of normal pressure, pressurization and reduced pressure, but it is usually advantageous to carry out the reaction under normal pressure. Reaction temperature is -20 to 5
The temperature is selected from the range of 0 ° C., and in many cases, heat is generated during the polymerization. The reaction time depends on other conditions and cannot be specified unconditionally.
It takes 2 to 10 hours.

In the present invention, an oligomer of dihydric phenol (I) having a terminal chloroformate group and having a degree of polymerization of 2 to 4 as a main component is obtained in this manner. Polyhydric phenol (II) is interfacially polycondensed in a mixture of a solution of the oligomer and the dihydric phenol (II) in a water-insoluble organic solvent with an aqueous alkali solution to obtain a polycarbonate copolymer .

As the organic solvent used in the interfacial polycondensation reaction, the same organic solvents as those used in the oligomer formation reaction in the preceding step can be used, and in particular, halogenated hydrocarbon solvents such as methylene chloride are preferably used. Can be

Examples of the aqueous alkali solution used in the interfacial polycondensation reaction include aqueous solutions of alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, and alkali metal carbonates such as sodium carbonate and potassium carbonate. Among them, aqueous solutions of sodium hydroxide and potassium hydroxide are preferably used, but are not limited thereto.

The proportion of the alkali used may be appropriately determined in consideration of the stoichiometric ratio (equivalent) of the reaction. Specifically, when the dihydric phenol (II) to be used or a part of the dihydric phenol (I) is added as a post-addition monomer to the reaction step as described above, the post-addition amount of the dihydric phenol (II) It is preferable to use 2 equivalents or a slight excess of alkali relative to the total number of moles of I) and dihydric phenol (II) (1 mole usually corresponds to 2 equivalents).

The polycondensation of the oligomer of dihydric phenol (I) with the dihydric phenol (II) by the interfacial polycondensation reaction is carried out by using the above organic solvent solution in which the oligomer and dihydric phenol (II) are uniformly dissolved and the above alkaline aqueous solution. The mixture is vigorously stirred.

In order to promote the polycondensation reaction, a catalyst such as a tertiary amine such as triethylamine or a quaternary ammonium salt is used.
It is desirable to carry out the reaction by adding a monohydric phenol such as p-tert-butylphenol or phenylphenol as a molecular weight regulator. If desired, a small amount of an antioxidant such as sodium sulfite or hydrosulfide may be added. The reaction pressure can be any of reduced pressure, normal pressure and pressurized pressure, but usually, it can be suitably performed at normal pressure or about the self-pressure of the reaction system. Reaction temperature is -20 to 50
The temperature is selected from the range of ° C., and in many cases, heat is generated during the polymerization. Since the reaction time varies depending on other conditions such as the reaction temperature, it cannot be unconditionally specified, but is usually 0.5 to 10 hours.

In the method of the present invention, the above reaction conditions,
The amount of the molecular weight modifier to be used is determined by adjusting the concentration of the obtained polycarbonate copolymer to 0.5 g / methylene chloride as a solvent.
The dl solution is preferably adjusted to have a reduced viscosity at 20 ° C. [η _sp / c] of 0.2 to 2.5 dl / g. If the reduced viscosity of the obtained polycarbonate copolymer is less than 0.2 dl / g, the mechanical strength may be insufficient. For example, when such a polycarbonate copolymer is used as a binder resin for a photosensitive layer of an electrophotographic photosensitive member, the photosensitive layer is worn out due to insufficient surface hardness of the photosensitive layer, and the printing life is shortened in practical use. . The reduced viscosity of the obtained polycarbonate copolymer is 2.5 dl.
/ G, the solution viscosity increases, and the molding means may be restricted. For example, when such a polycarbonate copolymer is used as a binder resin for an electrophotographic photosensitive member, it becomes difficult to form a photosensitive layer by a solution coating method.

In some cases, the obtained polycarbonate copolymer is appropriately subjected to a physical treatment (mixing, fractionation, etc.) and / or a chemical treatment (polymer reaction, cross-linking treatment, partial decomposition treatment, etc.) to obtain a desired product. It can also be obtained as a polycarbonate copolymer having a reduced viscosity [η _sp / c].

The obtained reaction product (crude product) can be subjected to various post-treatments such as a known separation and purification method and recovered as a polycarbonate copolymer having a desired purity (purity).

[0033]

The present invention will be described below in detail with reference to examples, but the present invention is not limited to these examples.

Example 1 54.7 g (0.2%) of 2,2-bis (4-hydroxyphenyl) propane (bisphenol A) as a starting monomer.
24 mol) in an aqueous solution of sodium hydroxide having a concentration of 8% by weight.
Dissolve in 50 ml, this aqueous solution and methylene chloride 250 m
1 was introduced into a reactor equipped with baffles, and phosgene gas was blown in at a rate of 950 ml / min for 15 minutes while vigorously stirring at about 10 ° C. After allowing this reaction solution to stand, the organic layer was separated to obtain a methylene chloride solution of an oligomer of bisphenol A having a degree of polymerization of 2 to 4 and a molecular terminal having a chloroformate group.

To the oligomer solution, 30.6 g (0.018 mol) of the following dihydric phenol, 205 methylene chloride
ml was introduced into a reactor equipped with baffles, stirred at about 10 ° C. to form a uniform solution. Further, 0.15 g of p-tert-butylphenol as a terminal stopper and 11.2 g (0.05%) of bisphenol A as a post-added monomer.
Mol) in a sodium hydroxide aqueous solution having a concentration of 8% by weight.
Then, 5 ml of a 10% by weight aqueous solution of triethylamine was added thereto, and the mixture was maintained at about 10 ° C. and vigorously stirred to carry out a polycondensation reaction.

[0036]

Embedded image

After completion of the reaction, the organic layer was diluted by adding 1 liter of methylene chloride, washed with water, dilute hydrochloric acid and water in that order, and then poured into methanol to obtain 98 g of a polycarbonate copolymer.

The polycarbonate copolymer thus obtained has a concentration of 0.5 g / d using methylene chloride as a solvent.
reduced viscosity at 20 ° C. [η _sp / c] of 0.1 l
GPC using 78 dl / g using THF as a solvent
As a result of the analysis, a single peak representing a uniform molecular weight distribution was M
w: around 37,000, with Mw / Mn of 1.9
It was 8. ¹ H-NMR spectrum analysis confirmed that the polycarbonate copolymer was composed of the following repeating units.

[0039]

Embedded image

Example 2 72 g (0.25 mol) of 4,4'-dihydroxytetraphenylmethane (bisphenol TP) as a raw material monomer was 550 m of a 10% by weight aqueous solution of potassium hydroxide.
Then, this aqueous solution and 250 ml of methylene chloride were introduced into a reactor equipped with baffles, and phosgene gas was blown in at a rate of 950 ml / min for 15 minutes while vigorously stirring at about 10 ° C. After allowing this reaction solution to stand, the organic layer was separated to obtain a methylene chloride solution of an oligomer of bisphenol TP having a degree of polymerization of 2 to 4 and a molecular terminal having a chloroformate group.

To this oligomer solution, 13.0 g (0.01 mol) of the following dihydric phenol, 185 m of methylene chloride
was introduced into a reactor equipped with baffles, kept at about 10 ° C., and stirred to obtain a uniform solution. In addition, p
A mixture of 0.15 g of -tert-butylphenol and 150 ml of an aqueous potassium hydroxide solution, 5 ml of a 10% by weight aqueous solution of triethylamine was added, and the mixture was vigorously stirred at about 10 ° C. to carry out a polycondensation reaction.

[0042]

Embedded image

After completion of the reaction, the organic layer was diluted by adding 1 liter of methylene chloride, washed with water, dilute hydrochloric acid and water in that order, and then poured into methanol to obtain 97 g of a polycarbonate copolymer.

The polycarbonate copolymer thus obtained has a concentration of 0.5 g / d using methylene chloride as a solvent.
reduced viscosity at 20 ° C. [η _sp / c] of 0.1 l
GPC using 75 dl / g and THF as a solvent
As a result of the analysis, a single peak representing a uniform molecular weight distribution was M
w: It was confirmed at around 36,000. ¹ H-NMR spectrum analysis confirmed that the polycarbonate copolymer was composed of the following repeating units.

[0045]

Embedded image

Comparative Example 1 EP-A-0 500 087 (19)
92) According to the method described in 92), 54.7 g (0.24 mol) of bisphenol A and 108 g (0.03 mol) of the following dihydric phenol as raw material monomers were added to 550 ml of a 8% by weight aqueous sodium hydroxide solution and stirred vigorously. However, it did not dissolve, a uniform solution was not obtained, and a dispersion of an oily substance was obtained.

[0047]

Embedded image

This dispersion was mixed with p-te as a terminal stopper.
0.15 g of rt-butylphenol, 5 ml of a 10% by weight aqueous solution of triethylamine, and 250 ml of methylene chloride
Was introduced into a reactor equipped with baffles, whereby white crystals precipitated. The reaction solution was kept at about 10 ° C., and phosgene gas was blown in at a rate of 340 ml / min for 30 minutes while being vigorously stirred so that the crystals were finely crushed. Furthermore, stirring was continued at room temperature for 2 hours to complete the polymerization. Thereafter, the organic layer was diluted by adding 1 liter of methylene chloride,
After washing with water, diluted hydrochloric acid and water in that order, the resultant was poured into methanol to obtain a white polycarbonate copolymer.

The thus obtained polycarbonate copolymer had a concentration of 0.5 g / d using methylene chloride as a solvent.
reduced viscosity at 20 ° C. [η _sp / c] of 0.1 l
GPC using 45 dl / g using THF as a solvent
As a result of the analysis, a distribution line having two peaks indicating a non-uniform molecular weight distribution was confirmed. ¹ H-NMR spectrum analysis confirmed that the polycarbonate copolymer was composed of the following repeating units.

[0050]

Embedded image

[0051]

According to the method of the present invention, it is possible to easily and stably obtain a polycarbonate copolymer containing not only excellent transparency and heat resistance but also a high molecular weight and high strength siloxane unit. The polycarbonate copolymer obtained by the method of the present invention is extremely useful as a material for general industrial materials and electronic / electric equipment parts, and particularly, utilizing its excellent mechanical strength, for example, abrasion resistance, to obtain an electrophotographic photosensitive material. By using as a binder resin of the photosensitive layer of the body, it becomes possible to obtain an electrophotographic photosensitive member excellent in printing durability and electrophotographic properties.

────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Tomohiro Nagao 1280 Kamiizumi, Sodegaura-shi, Chiba Idemitsu Kosan Co., Ltd. (56) References JP-A-3-79626 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C08G 64/00-64/42

Claims (1)

(57) [Claims] 1. A compound represented by the following general formula (I) [Wherein, R ¹ and R ² are each independently a halogen atom, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 5 to 12 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 12 carbon atoms. A and b are each independently an integer of 0 to 4, Y is a single bond, -O-, -CO-, -S-, -SO
—, —SO ₂ —, —CR ³ R ⁴ — (where R ³ and R ⁴ are each independently a hydrogen atom, a trifluoromethyl group, an alkyl group having 1 to 12 carbon atoms, a cyclo group having 5 to 12 carbon atoms) An alkyl group or a substituted or unsubstituted aryl group having 6 to 12 carbon atoms), a 1,1-cycloalkylidene group having 5 to 8 carbon atoms, or an α, ω-alkylene group having 2 to 12 carbon atoms. And a dihydric phenol (I) represented by the following general formula (II): (Wherein, R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ and R ¹⁰ are each independently a hydrogen atom, an alkyl group having 1 to 12 carbon atoms or a substituted or unsubstituted aryl having 6 to 12 carbon atoms. And R is
¹¹ and R ¹² are each independently a halogen atom, carbon number 1 to 6
Is an alkyl group or a substituted or unsubstituted aryl group having 6 to 12 carbon atoms, c and d are each independently an integer of 0 to 4, and X is a substituted or unsubstituted alkylene group having 1 to 6 carbon atoms. Wherein n is an integer of 1 to 6, p is a natural number, q is 0 or a natural number, and p + q is a natural number less than 100. ) Represented by the dihydric phenol (I)
In producing a polycarbonate copolymer by reacting I) with an ester-forming compound, the dihydric phenol (I) has a terminal chloroformate group by the reaction of the ester-forming compound and has a degree of polymerization. 2
And then forming the oligomer and the dihydric phenol (II) with a solution of the oligomer and the dihydric phenol (II) in a water-insoluble organic solvent. A method for producing a polycarbonate copolymer, comprising interfacial polycondensation in a mixed solution with an aqueous alkali solution.