TW201542619A - Method for producing polycarbonate resin - Google Patents

Abstract

A method for producing a polycarbonate resin by reacting a polycarbonate oligomer having a weight average molecular weight of less than 5000 with an aqueous alkali solution containing a bivalent phenol, said method being characterized by comprising: introducing the polycarbonate oligomer, 3-pentadecylphenol produced from a natural material and having a purity of 97.5% by mass or more and a caustic alkali to an inlet port for a first reaction zone to cause the reaction of the polycarbonate oligomer with 3-pentadecylphenol in the first reaction zone, thereby producing a reaction solution containing a polycarbonate oligomer in which some of terminal groups are 3-pentadecylphenoxy groups; and then introducing the reaction solution produced in the first reaction zone, an aqueous alkali solution containing a bivalent phenol and a caustic alkali to an inlet port for a second reaction zone, wherein the whole volume of the caustic alkali to be introduced to the second reaction zone is introduced through the inlet port for the second reaction zone, and the reaction of these components is performed in the second reaction zone.

Description

Method for producing polycarbonate resin

The present invention relates to a method of producing a polycarbonate resin. More specifically, it relates to a method for producing a polycarbonate resin having a pentadecylphenoxy group at a terminal group by an interfacial polymerization method.

Polycarbonate resin is excellent in transparency, heat resistance, and mechanical properties, and is used in a wide range of applications such as OA (office automation), housings for home appliances, electrical and electronic components, and optical materials such as lenses. . In recent years, it has been necessary to further improve fluidity in order to reduce the thickness and size of a molded article, or to increase the molding cycle.

As a method for improving the fluidity of a molding material using a polycarbonate resin, a plasticizer or a use such as ABS (Acrylonitrile-Butadiene-Styrene, acrylonitrile-butadiene-styrene), HIPS (High) has been used. A method of a resin having excellent fluidity such as styrene resin such as Impact Polystyrene or high impact polystyrene or AS (Acrylonitrile-Styrene). However, although these methods can improve the fluidity of the polycarbonate resin, there is a problem that the excellent impact resistance of the polycarbonate resin is lowered.

As a method of producing a polycarbonate resin, a polymerization method using an interfacial polymerization method or a transesterification method is known. In these polymerization methods, in order to adjust the molecular weight of the obtained polycarbonate resin, a terminal blocking agent (molecular weight modifier) is used.

It is known to avoid the above problems by using a long-chain alkyl phenol as an end seal The end agent changes the structure of the polycarbonate resin itself, thereby improving the fluidity.

In the method of producing a polycarbonate resin using the above-mentioned long-chain alkyl phenol as a terminal blocking agent, Patent Document 1 and Patent Document 2 describe a production method using an interfacial polymerization method using 3-pentadecylphenol. However, the production methods described in Patent Documents 1 and 2 only describe a laboratory batch production method in which a raw material is charged into a flask and a reaction is carried out by adding carbonium chloride to the raw material liquid.

[Previous Technical Literature] [Patent Literature]

Patent Document 1: Japanese Patent Laid-Open Publication No. 2005-524923

Patent Document 2: Japanese Patent Laid-Open Publication No. 2003-41011

When the above-mentioned 3-pentadecylphenol is used as the terminal blocking agent and the polycarbonate resin is continuously produced by the interfacial polymerization method, if 3-pentadecylphenol is used in the polycondensation step, there is a reaction temperature. As a result, the terminal hydroxyl group ratio of the obtained polycarbonate resin becomes high, and the effect on the YI (yellowness index) value of the molded article is adversely affected.

Further, in the polycondensation step, caustic alkali must be used in order to promote the polycondensation reaction, but when the caustic alkali is added in portions in the polycondensation step or added from the middle of the polycondensation step, when the self-polymerization condensation step is carried out When the obtained reaction liquid (emulsion solution) is separated into an aqueous phase and an organic phase containing a polycarbonate resin, there is a problem that the separation property is deteriorated and the production efficiency is deteriorated.

An object of the present invention is to provide a 3-pentadecylphenol and caustic in the reaction step when a polycarbonate resin is produced by an interfacial polymerization method using 3-pentadecylphenol as a terminal blocking agent. The position at which the alkali is added, whereby the obtained polycarbonate resin molded article has a good YI value and is excellent in productivity. law.

The inventors of the present invention conducted intensive studies and found the following method for producing a polycarbonate resin, which was completed by using interfacial polymerization method using 3-pentadecylphenol as a terminal blocking agent. In the case of the polycarbonate resin, the addition position of the 3-pentadecylphenol and the caustic alkali is set to an appropriate position, whereby the obtained polycarbonate resin molded article has a good YI value and is excellent in productivity.

That is, the present invention relates to the following [1] to [13].

[1] A method for producing a polycarbonate resin, which comprises reacting a polycarbonate oligomer having a weight average molecular weight of less than 5,000 with an aqueous alkaline solution of a diphenol to produce a polycarbonate resin, which is characterized in that Introducing the above-mentioned polycarbonate oligomer into the introduction port of the first reaction zone, and obtaining 3-pentadecylphenol and caustic having a purity of 97.5 mass% or more obtained from a natural product, and making polycarbonate in the first reaction zone The ester oligomer reacts with 3-pentadecylphenol to produce a reaction liquid containing a polycarbonate oligomer having a terminal group of a polycarbonate oligomer and a 3-pentadecylphenoxy group, and then And introducing the reaction liquid obtained from the first reaction zone, the alkaline aqueous solution of diphenol and caustic into the inlet to the second reaction zone, and the total amount of caustic which is introduced into the second reaction zone The introduction is carried out from the introduction port of the second reaction zone, and the reaction is carried out in the second reaction zone.

[2] The method for producing a polycarbonate resin according to the above [1], wherein at least one selected from the group consisting of p-tert-butylphenol, p-cumylphenol, and phenol is introduced into the second reaction zone as an end The blocking agent is reacted.

[3] The method for producing a polycarbonate resin according to the above [2], wherein the 3-pentadecylphenol introduced into the first reaction zone and the terminal blocking agent introduced into the second reaction zone are The ear ratio is 1:9~9:1.

[4] The method for producing a polycarbonate resin according to the above [1], wherein the end reaction agent is introduced into the second reaction zone and the second reaction zone is not reacted.

[5] The method for producing a polycarbonate resin according to any one of the above [1] to [4] wherein when the 3-pentadecylphenol is introduced into the first reaction zone, it is dissolved in two Imported in the form of a solution of methyl chloride.

[6] The method for producing a polycarbonate resin according to any one of the above [1] to [5] wherein the temperature of the second reaction zone is 20 to 36 °C.

[7] The method for producing a polycarbonate resin according to any one of the above [1] to [6] wherein 5 to 50 moles of all terminal groups of the polycarbonate oligomer obtained from the first reaction zone are The ear % is 3-pentadecylphenoxy.

[8] The method for producing a polycarbonate resin according to any one of the above [1] to [7] wherein the end of the polycarbonate oligomer obtained from the first reaction zone is 50 to 95 The ear % is a chloroformate group.

[9] The method for producing a polycarbonate resin according to any one of the above [1] to [8] wherein the obtained polycarbonate resin has a viscosity average molecular weight of 8,000 to 20,000.

[10] The method for producing a polycarbonate resin according to any one of the above [1] to [9], wherein the polycarbonate oligomer having a weight average molecular weight of less than 5,000 is obtained by using bisphenol A.

[11] The method for producing a polycarbonate resin according to any one of the above [1] to [10] wherein the diphenol is bisphenol A.

[12] The method for producing a polycarbonate resin according to any one of the above [1] to [11] wherein the pentadecylphenol introduced into the first reaction zone is reacted in the first reaction zone above 95.

[13] The method for producing a polycarbonate resin according to any one of the above [1] to [12] wherein a pipe mixer is used in the first reaction zone and/or the second reaction zone.

According to the present invention, the obtained polycarbonate resin molded article has a good YI value, can improve the color tone, and can improve the production efficiency of the polycarbonate resin.

Fig. 1 is a schematic view showing a reaction procedure used in Example 1.

Fig. 2 is a schematic view showing a reaction procedure used in Comparative Example 2.

Fig. 3 is a schematic view showing a reaction procedure used in Comparative Example 3.

The method for producing a polycarbonate resin of the present invention is to produce a polycarbonate resin by reacting a polycarbonate oligomer having a weight average molecular weight of less than 5,000 with an aqueous alkaline solution of a diphenol, and to go to the first reaction zone. Introducing the polycarbonate oligomer into the polycarbonate, a 3-pentadecylphenol having a purity of 97.5% by mass or more and a caustic alkali obtained from a natural product, and the polycarbonate oligomer and the 3 in the first reaction zone - a pentadecylphenol reaction to produce a reaction liquid containing a polycarbonate oligomer having a terminal group of a polycarbonate oligomer of 3-pentadecylphenoxy group, and then, from the first reaction zone The reaction liquid obtained in the domain, the alkaline aqueous solution of diphenol and the caustic are introduced into the inlet to the second reaction zone, and the reaction is carried out in the second reaction zone.

Hereinafter, a method for producing the polycarbonate resin of the present invention will be described in detail. Furthermore, in the present specification, the provisions regarded as preferable can be arbitrarily employed, and it is considered that the preferred combinations are better.

[Polycarbonate oligomers having a weight average molecular weight of less than 5,000]

The method for producing the polycarbonate oligomer having a weight average molecular weight of less than 5,000 used in the method for producing a polycarbonate resin of the present invention is not particularly limited, and for example, the following method can be preferably used.

First, an alkaline aqueous solution of diphenol is prepared, and an alkaline aqueous solution of the diphenol is mixed with an organic solvent such as dichloromethane, and the carbon chlorohydrazine is reacted in the presence of an aqueous alkaline solution of diphenol and an organic solvent while stirring. Thereby a polycarbonate oligomer is obtained.

As the diphenol, diphenol represented by the following formula (1) is preferably used.

[Chemical 1]

In the above formula (1), R ¹ and R ² each independently represent a halogen atom, an alkyl group having 1 to 6 carbon atoms or an alkoxy group having 1 to 6 carbon atoms. X represents a single bond, an alkylene group having 1 to 8 carbon atoms, an alkylene group having 2 to 8 carbon atoms, a cycloalkylene group having 5 to 15 carbon atoms, a cycloalkylene group having 5 to 15 carbon atoms, or a fluorenyl group. The group is an arylalkyl group having 7 to 15 carbon atoms, an arylalkylene group having 7 to 15 carbon atoms, -S-, -SO-, -SO ₂ -, -O- or -CO-. a and b each independently represent an integer from 0 to 4.

The diphenol represented by the formula (1) is not particularly limited, and is preferably 2,2-bis(4-hydroxyphenyl)propane [generally referred to as bisphenol A].

Examples of the diphenol other than bisphenol A include bis(4-hydroxyphenyl)methane, 1,1-bis(4-hydroxyphenyl)ethane, and 2,2-bis(4-hydroxyphenyl). Butane, 2,2-bis(4-hydroxyphenyl)octane, bis(4-hydroxyphenyl)phenylmethane, bis(4-hydroxyphenyl)diphenylmethane, 2,2-dual (4 -hydroxy-3-methylphenyl)propane, bis(4-hydroxyphenyl)naphthylmethane, 1,1-bis(4-hydroxy-t-butylphenyl)propane, 2,2-bis (4 -hydroxy-3-bromophenyl)propane, 2,2-bis(4-hydroxy-3,5-dimethylphenyl)propane, 2,2-bis(4-hydroxy-3-chlorophenyl)propane , 2,2-bis(4-hydroxy-3,5-dichlorophenyl)propane, bis(hydroxyaryl)alkane such as 2,2-bis(4-hydroxy-3,5-dibromophenyl)propane Class; 1,1-bis(4-hydroxyphenyl)cyclopentane, 1,1-bis(4-hydroxyphenyl)cyclohexane, 1,1-bis(4-hydroxyphenyl)-3,5 , 5-trimethylcyclohexane, 2,2-bis(4-hydroxyphenyl) Bis(hydroxyaryl)cycloalkanes such as alkane, 1,1-bis(4-hydroxyphenyl)cyclododecane; 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxy-3, Dihydroxyaryl ethers such as 3'-dimethylphenyl ether; 4,4'-dihydroxydiphenyl sulfide, 4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfide Dihydroxydiaryl sulfides; dihydroxydiaryl groups such as 4,4'-dihydroxydiphenylarylene, 4,4'-dihydroxy-3,3'-dimethyldiphenylarylene Anthraquinone; dihydroxydiaryl anthracene such as 4,4'-dihydroxydiphenylanthracene, 4,4'-dihydroxy-3,3'-dimethyldiphenylanthracene;4,4'- Dihydroxybiphenyl such as dihydroxybiphenyl; dihydroxydiaryl fluorene such as 9,9-bis(4-hydroxyphenyl)anthracene, 9,9-bis(4-hydroxy-3-methylphenyl)anthracene Class; 1,3-bis(4-hydroxyphenyl)adamantane, 2,2-bis(4-hydroxyphenyl)adamantane, 1,3-bis(4-hydroxyphenyl)-5,7-di Dihydroxy diaryl hydroxycycloalkane such as methyl adamantane; 4,4'-[1,3-phenylene bis(1-methylethylidene)]bisphenol, 10,10-bis(4-hydroxyl Phenyl)-9-fluorenone, 1,5-bis(4-hydroxyphenylthio)-2,3-dioxapentane, and the like.

These dihydric phenols may be used singly or in combination of two or more.

Further, the diphenol which is not contained in the diphenol represented by the above formula (1) can be used in combination with a diphenol having a structural unit represented by the following formula (2) and a diphenol represented by the formula (1). . By setting the copolymer having such a structural unit, the flame retardancy of the polycarbonate resin can be improved. The diorganosiloxane compound represented by the following formula (2-1) can be exemplified as the diphenol having a structural unit represented by the following formula (2).

In the above formula (2) or (2-1), R ⁷ , R ⁸ , R ⁹ and R ¹⁰ each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, and a carbon number. An alkoxy group of 1 to 6 or an aryl group having 6 to 12 carbon atoms. Z represents a phenol residue having a trimethylene group derived from a phenol compound having an allyl group. n means 30~1000.

The polyorganosiloxane having the above formula (2-1) is modified by, for example, terminal treatment of a polyorganosiloxane having a terminal hydrogen by using an allyl phenol compound such as 2-allylphenol or eugenol. Founder. The polyorganosiloxane having a phenol compound having an allyl group at the terminal can be synthesized by the method described in Japanese Patent No. 2662310.

The polyorganosiloxane is preferably dimethyloxane.

Further, a branching agent may be used for the diphenol containing the diphenol represented by the above formula (1) and the structural unit represented by the formula (2), and may have a branched structure in the main chain of the polycarbonate resin. The amount of the branching agent added is preferably 0.01 to 3 mol%, more preferably 0.1 to 1.0 mol%, based on the diphenol.

As a branching agent, for example, 1,1,1-tris(4-hydroxyphenyl)ethane, 4,4'-[1-[4-[1-(4-hydroxyphenyl)-1-methyl) Ethylethyl]phenyl]ethylidene]bisphenol, α,α',α"-tris(4-hydroxyphenyl)-1,3,5-triisopropylbenzene, 1-[α-methyl -α-(4'-hydroxyphenyl)ethyl]-4-[α',α'-bis(4"-hydroxyphenyl)ethyl]benzene, phloroglucinol, trimellitic acid, ruthenium A compound having three or more functional groups such as bis(o-cresol).

Further, as the alkaline aqueous solution, an alkaline aqueous solution such as sodium hydroxide or potassium hydroxide can be preferably used, and usually, the concentration thereof is preferably from 1 to 15% by mass. Further, the content of the diphenol in the alkaline aqueous solution is usually selected in the range of 0.5 to 20% by mass. Further, the amount of the organic solvent to be used is preferably such that the volume ratio of the organic phase to the aqueous phase is from 5/1 to 1/7, preferably from 2/1 to 1/4. The reaction temperature is usually selected from the range of 0 to 70 ° C, preferably 5 to 40 ° C. The concentration of the chloroformate terminal group in the obtained polycarbonate oligomer is usually from 0.6 to 0.9 mol/L, and can be used as a polycarbonate oligomer having a weight average molecular weight of less than 5,000.

In the polycarbonate oligomer production step, a monohydric phenol other than 3-pentadecylphenol, for example, a compound such as p-tert-butylphenol, p-cumylphenol or phenol may be used as a terminal blocking agent. Molecular weight modifiers, using such compounds to partially block one of the chloroformate end groups. Further, as the terminal blocking agent, a part of 3-pentadecylphenol used in the first reaction zone may be used in batches.

As the reactor, a tank type reactor can be used and manufactured in a continuous or batch manner. Further, it is also a preferred manufacturing method to continuously manufacture using a tubular reactor.

The reaction liquid obtained by the method described above is a milk phase containing an organic phase of a polycarbonate oligomer having a weight average molecular weight of less than 5,000 and an aqueous phase containing an impurity such as sodium chloride. It is obtained by the liquid state, and the reaction liquid in the state of the emulsion is allowed to stand still, and is separated into an organic phase containing a polycarbonate oligomer and an aqueous phase, and is obtained by using the separation in the first reaction zone. The organic phase of the polycarbonate oligomer. The lower limit of the weight average molecular weight of the polycarbonate oligomer having a weight average molecular weight of less than 5,000 is usually about 500.

[First reaction zone]

The purpose of the first reaction zone specified in the present invention is to make a part of the polycarbonate oligomer terminal group having a weight average molecular weight of less than 5,000 and a 3-pentadecane having a purity of 97.5 mass% or more obtained from a natural product. The phenol is reacted to produce a polycarbonate oligomer having a 3-pentadecylphenoxy group; no polycondensation reaction is carried out in the first reaction zone.

<Materials used in the first reaction zone> (i) polycarbonate oligomers having a weight average molecular weight of less than 5,000

As described above, the polycarbonate oligomer having a weight average molecular weight of less than 5,000 is used as an organic phase containing a polycarbonate oligomer having a weight average molecular weight of less than 5,000. As the organic solvent of the organic phase, dichloromethane is preferably used.

(ii) 3-pentadecylphenol obtained by natural product having a purity of 97.5% by mass or more

3-pentadecylphenol (hereinafter also sometimes referred to as PDP) is generally based on cardanol obtained by a distillation and extraction step of vegetable oil derived from natural products such as cashew nut shell liquid. The composition is obtained by subjecting a hydrogenation reaction treatment. The purity of a commercially available product of 3-pentadecylphenol is usually 90% by mass or more and less than 97.5% by mass. As the purity of the 3-pentadecylphenol used in the present invention, it is necessary to use a purity of 97.5% by mass or more. When the use is less than 97.5 mass%, the obtained polycarbonate resin molded article has a high YI value, and the transparency is lowered, which is not preferable. By purifying the low-purity 3-pentadecylphenol by distillation or crystallization, etc., it is possible to obtain 3-pentadecylphenol having a purity of 97.5% by mass or more. The highly purified 3-pentadecylphenol becomes a fine needle-like crystalline state. Regarding the size, the length is 200 to 300 μm, the diameter (long diameter) is about 50 μm, and the bulk density is extremely small, and is about 0.16 g/cm ³ . In the case of using such a fine powdery 3-pentadecylphenol, it is difficult to handle, so it is preferably used in a micropowder of 3-pentadecylphenol having a lower bulk density at 30 to 48 °C. The granulation is carried out by pressing, so that the bulk density is about 0.3 to 0.7 g/cm ³ . The size of the granules is not particularly limited, and the maximum diameter or length can be preferably set to 0.5 to 10 mm, more preferably 0.5 to 5 mm. The shape of the granulated material is not particularly limited, and may be a cylindrical shape, a rectangular parallelepiped shape, a cubic shape, an elliptical shape, a spherical shape, or a sheet shape.

Since the 3-pentadecyl phenol is not easily dissolved in the alkaline aqueous solution, when it is introduced into the first reaction zone, it is preferably dissolved in an organic solvent, preferably dissolved in dichloromethane. When a specific concentration of the 3-pentadecylphenol organic solvent solution is prepared in advance, the introduction amount per unit time becomes constant when continuously introduced into the first reaction zone, and thus the continuous production in the first reaction zone is performed. Be the better. The concentration of 3-pentadecylphenol in the above solution is usually preferably in the range of 5 to 35% by mass.

(iii) caustic

In order to carry out the reaction of the polycarbonate oligomer with the 3-pentadecylphenol in the first reaction zone, it is necessary to keep the reaction system alkaline (the caustic concentration is 0.05 to 0.7 N). As the caustic used, sodium hydroxide or potassium hydroxide is preferred. The caustic is preferably introduced as an aqueous solution.

(iv) other raw materials

In order to promote the reaction in the first reaction zone, a known catalyst used in the polymerization of the interface of the polycarbonate resin can be used. As the catalyst, an interphase transfer catalyst such as a tertiary amine or a salt thereof, a quaternary ammonium salt, a quaternary phosphonium or the like can be preferably used. Examples of the tertiary amine include triethylamine, tributylamine, N,N-dimethylcyclohexylamine, pyridine, and dimethylaniline. Further, as the tertiary amine salt, for example, The hydrochloride of the tertiary amine, the bromate, and the like. Examples of the quaternary ammonium salt include trimethylbenzylammonium chloride, triethylbenzylammonium chloride, tributylbenzylammonium chloride, trioctylmethylammonium chloride, and tetrabutyl chloride. The ammonium amide, tetrabutylammonium bromide, etc., as the quaternary phosphonium, for example, tetrabutylphosphonium chloride or tetrabutyl bromide Hey. These catalysts may be used alone or in combination of two or more. Among the above catalysts, a tertiary amine is preferred, and a triethylamine is preferred. If the catalyst is in a liquid state, it may be directly introduced or introduced into an organic solvent or water. Further, in a solid state, it can be introduced by dissolving it in an organic solvent or water.

<Reactor and reaction conditions used in the first reaction zone>

A line mixer, a static mixer, an orifice mixer, a stirred tank, or the like can be used as the reactor used in the first reaction zone to carry out the reaction in a continuous or batch manner. The reactors can also be used arbitrarily in combination and in the form of a plurality of reactors. Further, in such a reactor, in particular, if a line mixer is used, the reaction can be continuously carried out, and the reaction can be carried out efficiently, which is preferable.

In the first reaction zone, a polycarbonate oligomer having a chloroformate group at a terminal group is used as a polycarbonate oligomer having a weight average molecular weight of less than 5,000, using sodium hydroxide as a caustic, and using triethyl When a base amine (TEA) is used as a catalyst for a reaction accelerator, a polycarbonate oligomer having a weight average molecular weight of less than 5,000, 3-pentadecylphenol (PDP), caustic (NaOH), catalyst ( The preferred molar ratio of TEA: triethylamine is preferably based on the molar concentration (CF value) of the chloroformate group in the polycarbonate oligomer, and is set to PDP/CF=0.01~ 0.2, TEA/CF = 0.001 ~ 0.006, NaOH / CF = 0.1 ~ 0.3 range. Further, the reaction temperature is preferably controlled at 10 to 30 ° C, preferably 10 to 20 ° C. The reaction pressure is usually carried out under normal pressure. Under the reaction conditions, 95% or more of 3-pentadecylphenol (PDP) is reacted in the first reaction zone, and usually 50 to 95 mol%, preferably 50~, of all terminal groups can be obtained. 80 mol% of a polycarbonate oligomer remaining as a chloroformate group. The ratio of the 3-pentadecylphenoxy group in all the terminal groups of the polycarbonate oligomer is usually set in the range of 5 to 50 mol%, preferably 20 to 50 mol%.

[Second reaction zone]

The second reaction zone defined in the present invention is introduced from the first reaction zone. There is a reaction liquid of a polycarbonate oligomer having a 3-pentadecylphenoxy group at the end, an alkaline aqueous solution of diphenol, and caustic, and the reaction is carried out in the second reaction zone. The reaction in the second reaction zone is such that the polycarbonate oligomer is polycondensed with the above diphenol, and the polycarbonate obtained by at least a part of the terminal group having a 3-pentadecylphenoxy group is obtained. The resin (hereinafter sometimes referred to as PDP-PC) becomes the target viscosity average molecular weight. Hereinafter, the second reaction zone will be described.

<Materials used in the second reaction zone> (i) a reaction solution containing a polycarbonate oligomer having a 3-pentadecylphenoxy group at the terminal

A reaction liquid obtained from the first reaction zone as described above containing a polycarbonate oligomer having a 3-pentadecylphenoxy group at the terminal was used.

(ii) an alkaline aqueous solution of diphenol

The alkaline aqueous solution of diphenol used in the second reaction zone is used for polycondensation reaction with a polycarbonate oligomer having a 3-pentadecylphenoxy group at the end obtained from the first reaction zone. And make it high molecular weight.

As the diphenol to be used, a diphenol represented by the above formula (1) used in the production of a polycarbonate oligomer or a diphenol represented by the above formula (1) and the above formula are preferably used. (2) The diphenol of the structural unit represented by the above formula (1), and bisphenol A is exemplified.

Further, as the alkaline aqueous solution, an alkaline aqueous solution of sodium hydroxide or potassium hydroxide used in the production of a polycarbonate oligomer, which is caustic such as sodium hydroxide or potassium hydroxide, is preferably used. The concentration of the base is also preferably used in a concentration of from 1 to 15% by mass. Further, the content of the diphenol in the alkaline aqueous solution is also selected in the range of 0.5 to 20% by mass.

(iii) caustic

In the second reaction zone, high molecular weight can be achieved by reacting an aqueous alkaline solution of diphenol with a polycarbonate oligomer having a 3-pentadecylphenoxy group (interfacial polycondensation reaction) Chemical. The reaction is carried out in an aqueous alkaline solution of diphenol to form an alkali metal salt, the alkali metal salt of the diphenol and the polycarbonate oligomer having a 3-pentadecylphenoxy group dissolved in an organic solvent. The chloroformate group undergoes a dechlorination reaction at the interface between the organic phase and the aqueous phase, thereby performing polycondensation, thereby high molecular weight. Since the interfacial polycondensation reaction is carried out under alkaline conditions, in order to promote the reaction, it is necessary to add a caustic alkali such as sodium hydroxide or potassium hydroxide to cause a reaction.

The caustic alkali introduced from the inlet of the second reaction zone is preferably a concentration of 10 to 50% by mass, preferably such that the caustic concentration in the aqueous phase of the reaction liquid is 0.05 to 0.7 equivalent (N). The way is to supply caustic. The reaction rate is increased by the high concentration of caustic supplied in this manner, and as a result, the reaction time is shortened. Further, a polycarbonate resin (PDP-PC) having a high blocking ratio of a monohydric phenol at a polymer terminal (a decrease in a residual amount at a hydroxyl group) and a low molecular weight product is obtained.

The caustic alkali introduced from the inlet to the second reaction zone must be introduced into the inlet of the second reaction zone (in the case of using a plurality of reactors, the inlet of the reactor to be used first) The total amount used. When a part of caustic is used in batches from the middle of the second reaction zone, the reaction liquid (emulsion solution containing PDP-PC) is separated into an aqueous phase and an organic phase containing PDP-PC, and When the aqueous phase and the organic phase are separated by a washing step such as alkali washing, pickling, or water washing, the separation property is deteriorated, and the productivity is poor, which is not preferable.

(iv) other raw materials

A reaction liquid containing a polycarbonate resin which has been subjected to a polycondensation reaction is taken out from the outlet of the second reaction zone. Further, the reaction may be carried out without introducing a terminal blocking agent to the second reaction zone. Further, in order to adjust the molecular weight of the polycarbonate resin after completion of the reaction in the second reaction zone, a terminal blocking agent (molecular weight modifier) may be added to the second reaction zone. As the terminal blocking agent, a known terminal blocking agent other than 3-pentadecylphenol can be used, and at least one selected from the group consisting of p-tert-butylphenol, p-cumylphenol and phenol is preferably used. End Blocking agent. In the case where a terminal blocking agent is added to the second reaction zone, the molar ratio of the 3-pentadecylphenol introduced into the first reaction zone to the terminal blocking agent introduced into the second reaction zone is preferably It is in the range of 1:9~9:1.

Further, in order to promote the polycondensation reaction, the same catalyst used in the interfacial polymerization of the polycarbonate resin described in the first reaction zone may be used, and the preferred embodiment is also the same.

<Reactor and reaction conditions used in the second reaction zone>

In the second reaction zone, depending on the capacity of the reactor to be used, the reaction can be terminated using only one reactor, but the subsequent second reactor and the third reactor can be combined as needed. The reactor is set to the second reaction zone. As the reactor used in the second reaction zone, a stirring tank, a multistage stirring tank, a stirring tank, a static mixer, a line mixer, an orifice mixer, a piping, or the like can be used, in order to enable the reaction. Efficiently, it is preferred to use a line mixer. A plurality of these reactors may be arbitrarily combined and used.

The production of the polycarbonate resin of the present invention can be carried out continuously or in batch form. In the case of manufacturing in batch mode, first, in the reactor used as the first reaction zone, a polycarbonate oligomer having a weight average molecular weight of less than 5,000, 3-pentadecylphenol, and a catalyst are used. (TEA, etc.), caustic, reacting a polycarbonate oligomer with pentadecylphenol, and producing a polycondensation of 3-pentadecylphenoxy group in a part of the terminal group of the polycarbonate oligomer Carbonate oligomer. Then, it is only necessary to add caustic and diphenol to the same reactor and set the conditions of the second reaction zone (specifically, the caustic concentration is 0.05 to 0.7 N). That is, as long as the reaction conditions are adjusted using the same reactor, the conditions of the two reaction zones of the first reaction zone and the second reaction zone may be sequentially set.

The temperature in the second reaction zone is preferably set to 20 to 35 °C. In particular, when the temperature in the second reaction zone exceeds 35 ° C, the terminal hydroxyl group content of the molded article increases, and the YI value of the molded article becomes high. Therefore, it is preferably 35 ° C or lower.

[Steps after the reaction] (i) separation step

The mixed solution obtained after the reaction from the second reaction zone becomes an emulsion state, and must be separated from the emulsion into an organic phase containing a polycarbonate and an aqueous phase. Therefore, an appropriate organic solvent such as dichloromethane is added to the mixed solution after the reaction, and the mixture is appropriately diluted, and then separated into an aqueous phase and an organic phase containing a polycarbonate resin by standing or centrifuging.

(ii) washing step

In order to remove residual monomers, catalysts, alkaline substances, and the like as impurities, the organic phase containing the polycarbonate resin obtained by the separation in this manner is washed with an alkaline aqueous solution, an acidic aqueous solution, and pure water. Further, the washing mixture is separated into an organic phase containing a purified polycarbonate resin and an aqueous phase using a centrifugal separator or a static separation tank.

(iii) Concentration step

The washed and treated organic phase containing the purified polycarbonate resin is efficiently concentrated by a kneader, a powder bed granulator, a hot water granulator, or the like to a concentration range suitable for powdering or granulation. It is preferably 10 to 45% by mass.

(iv) powder. Granulation. Drying step

2. Known powders such as kneaders, powder bed granulators, hot water granulators, etc. a granulation method for powdering an organic phase containing a refined polycarbonate resin obtained in a concentration step. Granulation. Since the obtained powder/granules contain 1 to 8% by mass of an organic solvent such as dichloromethane to be used, it is preferred to further reduce the residual organic solvent to 1000 ppm or less by heat drying, drying under reduced pressure or the like.

According to the production method of the present invention, a polycarbonate resin (PDP-PC) having excellent transparency and a yellowness index (YI value) of 1.1 or less can be obtained. The polycarbonate resin obtained by the production method of the present invention may have a viscosity average molecular weight of 8,000 to 20,000.

Since the PDP-PC obtained by the production method of the present invention has a 3-pentadecylphenoxy group at the terminal group, it is excellent in fluidity, and since the YI value is low, the color tone of the molded article is excellent. Different from the above, it can be preferably used for a member for liquid crystal which requires transparency. Further, in the production method of the present invention, when the reaction liquid after polymerization is separated into an organic phase and an aqueous phase, the separation property is excellent, so that a method for producing a polycarbonate resin (PDP-PC) having a high production efficiency can be provided. .

The polycarbonate resin (PDP-PC) obtained by the method for producing a polycarbonate resin of the present invention can be mixed with a polycarbonate resin other than PDP-PC at any ratio to obtain a polycarbonate resin composition.

The polycarbonate resin is not particularly limited, and various known polycarbonate resins other than PDP-PC can be used.

In the above polycarbonate resin (PDP-PC) or polycarbonate resin (PDP-PC) composition, an antioxidant, a UV absorber, a flame retardant, a release agent may be used depending on the desired properties for the intended use. Additives such as inorganic fillers (glass fiber, talc, titanium oxide, mica, etc.), colorants, and light diffusing agents. The polycarbonate resin or the polycarbonate resin composition can be formed into a molded body by various molding methods such as injection molding, injection compression molding, extrusion molding, and blow molding.

The molded body obtained by molding the above polycarbonate resin (PDP-PC) or polycarbonate resin (PDP-PC) composition can be preferably used as a mobile phone, a liquid crystal television, a personal computer, an electronic dictionary, an electronic book, or the like. A member for a liquid crystal device used in a liquid crystal display device. The polycarbonate resin obtained in the present invention is excellent in fluidity, and therefore, particularly in the case of producing a molded article having a small thickness, it is preferably formed by injection molding, and is preferably used as a liquid crystal display device. A resin for a light guide plate or a light diffusion plate.

[Examples]

The invention will now be described in further detail by way of examples. Furthermore, the invention is not limited by the examples. In addition, the measurement evaluation in the Example and the comparative example was performed by the method shown below.

<Method for measuring the purity of <3-pentadecylphenol>

The purity of 3-pentadecylphenol is made by Agilent Technologies. AGILENT 1200", "L-column ODS" (4.6 mm ID × 150 mm, particle diameter 3 μm) was used for the column, and the mobile phase was measured using acetonitrile/formic acid buffer = 95/5 (vol/vol).

<Measurement of viscosity average molecular weight (Mv)>

The viscosity average molecular weight (Mv) of the polycarbonate resin was measured using a Ukrainian viscometer, and the viscosity of the dichloromethane solution at 20 ° C was measured, and the ultimate viscosity [η] was determined by the following formula.

[η]=1.23×10 ^-5 Mv ^0.83

<Measurement of end group composition amount>

The "JNM-LA500" manufactured by JEOL Ltd. was used to measure ¹ H-NMR (nuclear magnetic resonance) to calculate the terminal group composition of the polycarbonate resin.

<Measurement of flow rate (Q value)>

The amount of molten resin flowing out from a nozzle having a diameter of 1 mm and a length of 10 mm was measured using an overhead rheometer according to JIS K7210 at a pressure of 280 ° C and a pressure of 15.7 MPa using a polycarbonate resin pellet used for the measurement of the YI value. (×10 ^-2 mL/sec).

<Measurement of YI value>

To the obtained polycarbonate resin sheet, 500 mass ppm of Adekastab PEP36 [bis(2,6-di-t-butyl-4-methylphenyl)pentaerythritol phosphite manufactured by ADEKA Co., Ltd.] was added. 40mm with venting holes The uniaxial extruder was melt-kneaded and extruded at a resin temperature of 280 ° C and a screw rotation speed of 100 rpm to obtain granules. Using the obtained pellets, a molded article having a thickness of 3 mm was formed, and a spectrophotometer Σ90 manufactured by Nippon Denshoku Industries Co., Ltd. was used, according to the measurement area 30. The C2 light source is measured by the transmission method.

<Measurement of bulk density>

The bulk density was measured based on JIS K7365.

Production Example 1 <Production of High Purity 3-Pentadecylphenol>

A column with an inner diameter of 30 mm and a capacity of 500 mL was filled with McMahon Packing (Mc. MAHON Packing, size: 6 mm) and used as a rectification column, which was attached to a 2 L flask equipped with an internal temperature measuring device at the top of the packed column. An apparatus for adjusting the reflux ratio (return flow rate/distillation amount) and a device for measuring the temperature at the top of the tower are installed, and a pressure reducing degree adjusting device is further installed. 1006.96 g of 3-pentadecylphenol solid (manufactured by Tokyo Chemical Industry Co., Ltd., purity: 92.10% by mass) was supplied to the flask, and after nitrogen substitution, heating and depressurization were started. The distillation degree was set to 2 mmHg, the reflux flow rate/distillation amount=1, and the distillation fraction of the column top temperature of 205 to 210 ° C was taken out. At this time, the temperature of the flask was 230 to 245 °C. The amount of fractionation was 825.71 g (82% by mass), and the purity of 3-pentadecylphenol was 93.61% by mass.

Then, the obtained crude 3-pentadecylphenol was dissolved in a hot water bath at 60 ° C, and 70 g of the solution was placed in a standard bottle, and 420 g of n-hexane was added to dissolve it. The mixture was allowed to stand at room temperature for 12 hours, and the precipitated solid was filtered under reduced pressure, and then dried under reduced pressure at room temperature for 8 hours to obtain purified 3-pentadecylphenol as a fine powder. The purity of the purified 3-pentadecylphenol was 97.75 mass%, and the bulk density of the 3-pentadecylphenol fine powder was 0.16 g/cm ³ . The 3-pentadecylphenol fine powder having a purity of 97.75 mass% was placed in a roll press, and a load of 0.2 ton was applied per 1 cm of the roll width, followed by pulverization to obtain a granulated product having a maximum diameter of 3 mm. The powder temperature after granulation was 23.4 °C. The granulated bulk density was 0.46 g/cm ³ .

Example 1

As a polycarbonate oligomer, a concentration of 318 g/L and a chloroformate concentration of a bisphenol A aqueous solution of sodium hydroxide, carbonium chloride, dichloromethane, and p-tert-butylphenol (PTBP) can be used. 0.75 mol/L, weight average molecular weight (Mw) = 3,100, the functional group ratio in all terminal groups determined by NMR is p-tert-butylphenoxy (terminal group derived from PTBP): OH: chloroformic acid A solution of a polycarbonate oligomer (PCO) of an ester group (CF) = 3.3:7.7:89.0 was used for the starting material.

Furthermore, regarding the weight average molecular weight (Mw), THF (tetrahydrofuran, four Hydrogen furan) as a developing solvent, using GPC (gel permeation chromatograph) [column: TOSOH TSK-GEL MULTIPORE HXL-M (2) + Shodex KF801 (1), temperature 40 ° C, flow rate 1.0 ml/min, detector: RI], measured as a standard polystyrene-equivalent molecular weight (weight average molecular weight: Mw).

The polycarbonate oligomer was dissolved in dichloromethane at a flow rate of 20 liter/hr, and the purity of 97.75 mass% obtained in the above Production Example 1 was dissolved in dichloromethane to 12% by mass. The dichloromethane solution was flowed at a flow rate of 1.7 liter/hr (PDP/CF=0.057), a 4% by mass aqueous solution of triethylamine at a flow rate of 0.04 liter/hr, and a 10% by mass aqueous sodium hydroxide solution at 1.0 liter/hr. The flow rate of (NaOH/CF=0.2) was supplied to a TK line homogenizer 2SL type (manufactured by a special machine industry) having a turbine blade having a diameter of 43 mm and a diameter of 48 mm as a first reactor and having an internal volume of 0.3 liter. a reaction zone domain mixer], the reaction is carried out at 3000 rpm, and a part of the chloroformate group of the polycarbonate oligomer terminal group is reacted with 3-pentadecylphenol to obtain an end. One part of the base is a polycarbonate oligomer reaction solution of 3-pentadecylphenoxy.

The ratio of the 3-pentadecylphenoxy group contained in the polycarbonate oligomer reaction liquid to all the terminal groups of the polycarbonate oligomer is 32 mol%, and the ratio of the chloroformate group is 57 moles %. Further, the ratio of the terminal groups was determined by ¹ H-NMR. Further, the unreacted 3-pentadecylphenol contained in the polycarbonate oligomer reaction liquid was measured by ¹ H-NMR, and as a result, it was 0.1%, and it was confirmed that 99.7% of the supplied pentadecylphenol occurred. reaction. The temperature at the outlet of the first reaction zone (point a) was 20 °C. The polycarbonate oligomer discharged from the first reaction zone was cooled by a heat exchanger, and the temperature of the heat exchanger outlet (point b) was 15 °C.

Then, the reaction liquid from the outlet of the first reactor, bisphenol A was dissolved in a 5.6% by mass aqueous sodium hydroxide solution, and the aqueous solution (BPA-Na) at a concentration of 13.5% by mass was used at 11.5 liter/hr (NaOH/OH). Equivalent ratio = 1.03), a solution of a third molecular weight modifier, p-tert-butylphenol (PTBP), and a concentration of 24% by mass of a dichloromethane solution at 0.35 liter/hr (PTBP/CF=0.055), and 25% by mass. Aqueous sodium hydroxide solution is 0.64 liters /hr (NaOH/CF=1.3) was introduced into the second reactor as the second inner diameter of 9.2 mm, the length of 230 mm and the built-in 14 components of the Through the Mixer (made by Sumitomo Heavy Industries Co., Ltd.) [used as the second a pipe mixer of the first reactor in the reaction zone]. The CF value at this time represents the chloroformate group concentration of the polycarbonate oligomer used in the first reaction zone. The temperature at the second reactor outlet (point c) was 33 °C.

The reaction night was supplied to a 50 liter paddle-wing three-stage column type agitating tank [used as the second reactor of the second reaction zone] as a jacket for the third reactor for ending the reaction, and Polycondensation is carried out. Cooling water of 15 ° C was flowed through the casing, and the outlet temperature of the polymerization liquid was set to 35 ° C. The step of banding the first reaction zone to the second reaction zone is shown in FIG.

The polymerization solution was allowed to stand to separate into an organic phase containing a polycarbonate resin and an aqueous phase containing an excess of bisphenol A and NaOH. The amount of water in the organic phase after standing for 60 minutes was measured using a Karl Fischer moisture meter, and as a result, it was 2000 mass ppm. The organic phase is subjected to alkali washing, pickling, and water washing (washing with pure water until the conductivity in the aqueous phase after washing is 0.05 μS/m or less), thereby obtaining a transparent polymer solution as an organic phase.

The dichloromethane solution of the polycarbonate resin obtained by washing was concentrated and pulverized, and the obtained sheet was dried at 100 ° C under reduced pressure to obtain a polycarbonate resin sheet. The polycarbonate resin sheet has a viscosity average molecular weight of 11,500, a 3-pentadecylphenol content of 3-pentadecylphenoxy group of 3% by mass, and an unreacted 3-pentadecyl group in the sheet. The phenol was 9 ppm. Further, the hydroxyl terminal fraction with respect to all terminal groups was 1.9 mol%. The dried flakes were granulated by an extruder to prepare granules, and the flow rate value (Q value) of the granules was measured and found to be 123 × 10 ^-2 mL / sec. Further, using this pellet-forming plate, the yellowness index (YI value) was measured and found to be 1.0. The results obtained are shown in Table 1.

Example 2

The dichloromethane solution of the concentration of 24% by mass of the third butylphenol introduced into the second reaction zone in Example 1 was changed to 0.25 liter/hr (PTBP/CF=0.039), and the examples were 1 A polycarbonate resin was obtained in the same manner. The results are shown in Table 1.

Example 3

The dichloromethane solution of the 10-pentadecylphenol having a concentration of 12% by mass introduced into the first reaction zone in Example 1 was set to 0.57 liter/hr (PDP/CF=0.019), and was introduced into the second reaction. A polycarbonate resin was obtained in the same manner as in Example 1 except that the concentration of 24% by mass of the dichloromethane solution of the tert-butylphenol was changed to 0.59 liter/hr (PTBP/CF = 0.093). The results are shown in Table 1.

Example 4

The dichloromethane solution of the concentration of 12% by mass of 3-pentadecylphenol introduced into the first reaction zone in Example 1 was set to 3.34 liter/hr (PDP/CF=0.112), and the second reaction zone was not A polycarbonate resin was obtained in the same manner as in Example 1 except that the p-tert-butylphenol was introduced into the domain. The results are shown in Table 1.

Example 5

A 20-liter stirred tank with a 260 mm diameter Pfaudler blade attached to the sleeve was used as the first reactor in the first reaction zone of Example 1, and was operated at a number of revolutions of 290 rpm, in addition to The reaction of Example 1 was carried out in the same manner. Cooling water of 15 ° C was passed through the casing for cooling. In the second reaction zone, using the same line mixer as the first reactor of Example 1 [used as the first reactor of the second reaction zone], the polymerization was carried out at a number of revolutions of 4000 rpm as a follow-up The three reactors were terminated with a 30 liter vertical crucible [used as the second reactor of the second reaction zone] without a stirrer. The results are shown in Table 1.

Comparative example 1

In Example 1, it was changed to 3-pentadecylphenol having a purity of 97.75 mass%, and a 3-pentadecylphenol solid having a purity of 92.10% by mass (manufactured by Tokyo Chemical Industry Co., Ltd.) was used. A polycarbonate resin was obtained in the same manner as in Example 1. The results are shown in Table 1.

Comparative example 2

The first reactor as the first reaction zone in Example 1 was stopped, and a 12% by mass of a solution of 3-pentadecylphenol in a first reaction zone was added to a dichloromethane solution of triethylamine. The same procedure as in Example 1 was carried out except that the 4 mass% aqueous solution and the 10 mass% sodium hydroxide aqueous solution were introduced into the inlet of the second reaction zone (the step is shown in Fig. 2). The results are shown in Table 1.

Comparative example 3

A 25 mass% aqueous sodium hydroxide solution introduced into the second reaction zone in Example 1 was introduced into the inlet of the second reactor (inlet of the second reaction zone) at 0.25 liter/hr (Na/CF = 0.5). A polycondensation reaction was carried out in the same manner as in Example 1 except that the mixture was introduced into the outlet of the second reactor at 0.39 liter/hr (Na/CF = 0.8) (the step is shown in Fig. 3). When the obtained polymerization liquid is allowed to stand and separated into an organic phase containing a polycarbonate resin and an aqueous phase containing an excessive amount of bisphenol A and NaOH, the organic phase and the aqueous phase are not separated at all even after 60 minutes after standing. .

It is clear from Table 1 that in the method for producing a polycarbonate resin of the present invention of Examples 1 to 5, the separation of the reaction liquid obtained after the polycondensation reaction into the organic phase and the aqueous phase is good, and the organic phase is good. The water concentration in the medium is also stable. Further, it was found that the obtained polycarbonate resin was molded, and the YI value obtained by measuring the molded article was also good. On the other hand, although Comparative Example 1 was used, 3-pentadecylphenol having a low purity was used, but the YI value was higher than that of the examples, and the transparency was lowered. In Comparative Example 2, the first reaction zone was not used, but the temperature in the second reaction zone increased, and the obtained hydroxyl group fraction of the polycarbonate resin became high, and the YI value of the molded article became high. Further, Comparative Example 3 is an example in which a caustic alkali used in the second reaction zone is added in batches. It is shown that in Comparative Example 3, the polymerization liquid obtained after the reaction could not be separated, and thus the evaluation of the molded article could not be performed.

[Industrial availability]

In the method for producing a polycarbonate resin of the present invention, the reaction liquid after the reaction has good oil-water separation property, can improve production efficiency, and can lower the YI value of the molded article, thereby obtaining a polycarbonate resin excellent in color tone such as transparency. .

Claims (13)

A method for producing a polycarbonate resin, which comprises reacting a polycarbonate oligomer having a weight average molecular weight of less than 5,000 with an aqueous alkaline solution of a diphenol to produce a polycarbonate resin, which is characterized in that: Introducing the above-mentioned polycarbonate oligomer into the introduction port of the domain, 3-pentadecylphenol and caustic having a purity of 97.5% by mass or more obtained from a natural product, and oligomerizing the polycarbonate in the first reaction zone Reacting with 3-pentadecylphenol to produce a reaction liquid containing a polycarbonate oligomer having a terminal group of a polycarbonate oligomer and a 3-pentadecylphenoxy group, and then, The reaction liquid obtained in the first reaction zone, the alkaline aqueous solution of diphenol and the caustic are introduced into the inlet to the second reaction zone, and the total amount of caustic introduced into the second reaction zone is from the second The introduction port of the reaction zone is introduced, and the reaction is carried out in the second reaction zone. The method for producing a polycarbonate resin according to claim 1, wherein at least one selected from the group consisting of p-tert-butylphenol, p-cumylphenol, and phenol is introduced as a terminal blocking agent to the second reaction zone. And react. The method for producing a polycarbonate resin according to claim 2, wherein the molar ratio of the 3-pentadecylphenol introduced into the first reaction zone to the terminal blocking agent introduced into the second reaction zone is 1 :9~9:1. The method for producing a polycarbonate resin according to claim 1, wherein the terminal is not introduced into the second reaction zone to carry out the reaction in the second reaction zone. The method for producing a polycarbonate resin according to any one of claims 1 to 4, wherein when the 3-pentadecylphenol is introduced into the first reaction zone, a solution obtained by dissolving in methylene chloride is used. The form is imported. The method for producing a polycarbonate resin according to any one of claims 1 to 5, wherein the temperature of the second reaction zone is 20 to 36 °C. The method for producing a polycarbonate resin according to any one of claims 1 to 6, wherein 5 to 50 mol% of all terminal groups of the polycarbonate oligomer obtained from the first reaction zone are 3-ten Pentaalkylphenoxy. The method for producing a polycarbonate resin according to any one of claims 1 to 7, wherein 50 to 95 mol% of all terminal groups of the polycarbonate oligomer obtained from the first reaction zone are chloroformic acid Ester group. The method for producing a polycarbonate resin according to any one of claims 1 to 8, wherein the polycarbonate resin obtained has a viscosity average molecular weight of 8,000 to 20,000. The method for producing a polycarbonate resin according to any one of claims 1 to 9, wherein the polycarbonate oligomer having a weight average molecular weight of less than 5,000 is obtained by using bisphenol A. The method for producing a polycarbonate resin according to any one of claims 1 to 10, wherein the diphenol is bisphenol A. The method for producing a polycarbonate resin according to any one of claims 1 to 11, wherein the pentadecylphenol introduced into the first reaction zone is reacted in the first reaction zone for 95% or more. The method for producing a polycarbonate resin according to any one of claims 1 to 12, wherein a pipe mixer is used in the first reaction zone and/or the second reaction zone.