Polycarbonate resin manufacturing method

Abstract

To provide a method for producing a polycarbonate resin having a stably good color tone.SOLUTION: Provided is a method for producing a polycarbonate resin including a structural unit derived from an aromatic dihydroxy compound represented by formula (1), comprising a step of polymerizing the aromatic dihydroxy compound represented by the general formula (1) using a methanol solution having a concentration of the aromatic dihydroxy compound represented by the general formula (1) of 30 mass% and a raw material, a slurry solution of which, obtained by mixing pure water in a mass of 9 times the mass of the methanol solution, has conductivity of 5.0 μS / cm or less. (In the formula, R1 and R2 are independently H, a halogen atom, an alkyl group having 1 to 20 carbon atoms, or an aryl group having 6 to 30 carbon atoms; and m and n represent integers of 0 to 4.)SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a method for producing a polycarbonate resin. [Background technology]

[0002] Polycarbonate resins have excellent transparency and mechanical strength and are used in a variety of applications. Generally, polycarbonate resins using bisphenol A as a raw material monomer are commercially available, but for special applications such as inks and copier components, polycarbonate resins using bis(4-hydroxyphenyl)ether (hereinafter abbreviated as "DHDE") as a raw material monomer are known (for example, Patent Documents 1 and 2).

[0003] Polycarbonate resin is characterized by its high transparency, and particularly for ink applications, extremely strict quality stability is required for coloring. However, DHDE is not mass-produced industrially at the same high quality as bisphenol A, and even with the same purity, the quality of polycarbonate resin produced can vary unexpectedly depending on the lot (it is difficult to determine the quality of DHDE based solely on the concentration quantified by general analysis such as liquid chromatography) or the manufacturer (production equipment) used. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 6-51544 [Patent Document 2] Japanese Patent Application Laid-Open No. 2016-160291 DISCLOSURE OF THE INVENTION [Problem to be solved by the invention]

[0005] The cause of these variations has not been clarified, and there has been a need to develop a new manufacturing method that can stabilize the quality of polycarbonate resin made from DHDE, particularly to suppress discoloration. [Means for solving the problem]

[0006] The present inventors have conducted extensive research to solve the above-mentioned problems in the prior art, and have found that the above-mentioned problems can be solved by the present invention described below. <1> A method for producing a polycarbonate resin containing a structural unit derived from an aromatic dihydroxy compound represented by the following general formula (1), The method for producing the polycarbonate resin includes a step of polymerizing the aromatic dihydroxy compound represented by the general formula (1) using raw materials, the raw materials having a conductivity of 5.0 μS / cm or less when a methanol solution containing the aromatic dihydroxy compound represented by the general formula (1) at a concentration of 30 mass % is mixed with pure water in an amount 9 times by mass of the methanol solution. [ka] (In the general formula (1), R1 and R2 each independently represent a hydrogen atom, a halogen atom, an optionally substituted or branched alkyl group having from 1 to 20 carbon atoms, or an optionally substituted aryl group having from 6 to 30 carbon atoms; m and n each independently represent an integer of 0 to 4. <2> The aromatic dihydroxy compound represented by the general formula (1) is represented by the following general formula (1-1): <1> This is the manufacturing method described in [ka] (In the general formula (1-1), R1, R2, m, and n are the same as those in general formula (1). <3> The aromatic dihydroxy compound represented by the general formula (1) is bis(4-hydroxyphenyl) ether. <1> or <2> This is the manufacturing method described in <4> The Hazen color number (APHA) of a solution obtained by dissolving 4 g of the polycarbonate resin in 25 ml of methylene chloride is 30 or less. <1> ~ <3> The manufacturing method according to any one of the above items. <5> the polymerization step further uses at least one raw material monomer selected from the group consisting of 1,1-bis(4-hydroxyphenyl)cyclohexane, 2,2-bis(4-hydroxyphenyl)-4-methylpentane, and 2,2-bis(4-hydroxy-3-methylphenyl)propane. <1> ~ <4> The manufacturing method according to any one of the above items. [Effects of the Invention]

[0007] The method for producing a polycarbonate resin of the present invention makes it possible to reliably produce a DHDE-type polycarbonate resin having a good hue stably. DETAILED DESCRIPTION OF THE INVENTION

[0008] The present invention will be described in detail below. Note that the present invention is not limited to the following embodiments, and can be implemented by making any modifications within the scope of the effects of the invention.

[0009] The aromatic dihydroxy compound represented by general formula (1) can be synthesized by known methods, and also commercially available products are available from several companies. However, even if the purity determined by general analysis such as liquid chromatography is equivalent, polycarbonate resins obtained by polymerization using the aromatic dihydroxy compound often show variations in APHA, etc. According to the investigations of the present inventors, although several impurities such as halide ions, alkali metal ions, transition metal salt ions, and organic compound ions were detected in the aromatic dihydroxy compound represented by general formula (1), the causative substance that directly affects APHA could not be identified.

[0010] However, as a result of trial and error, the present inventors have found that polycarbonate resins having good hues can be stably produced by using raw material monomers such that the electrical conductivity of a slurry solution obtained by mixing a methanol solution containing a 30% by mass concentration of the aromatic dihydroxy compound represented by general formula (1) with 9 times the mass of the methanol solution of pure water is 5.0 μS / cm or less; in other words, by using raw material monomers such that the electrical conductivity of a slurry solution obtained by adding 9 times the mass of pure water to a methanol solution in which 30% by mass of the aromatic dihydroxy compound represented by general formula (1) is dissolved to precipitate the aromatic dihydroxy compound represented by general formula (1) is 5.0 μS / cm or less, preferably 4.6 μS / cm or less, and more preferably 3.8 μS / cm or less. Here, if the conductivity of the slurry solution is 5.0 μS / cm and the conductivity of a blank solution not using the aromatic dihydroxy compound represented by general formula (1) is 1.0 μS / cm, the difference from the blank, Δ4.0 μS / cm, is estimated to be the increase in conductivity due to water-soluble impurities. There is no particular lower limit to the electrical conductivity, but it is equivalent to that of a sample containing no aromatic dihydroxy compound (blank). For example, the lower limit of the dielectric constant is 1.0 μS / cm.

[0011] Furthermore, with regard to the aromatic dihydroxy compound represented by general formula (1) having the above-mentioned dielectric constant exceeding 5.0 μS / cm, the aromatic dihydroxy compound represented by general formula (1) is separated (filtered) from the slurry after the conductivity test described below, dried, and then the conductivity test is conducted again in the same manner. If the conductivity is 5.0 μS / cm or less, a polycarbonate resin with a good hue is obtained.

[0012] (a) Raw material monomer The polycarbonate resin is produced using raw material monomers that form the structural units of the polymer chain of the polycarbonate resin. The raw material monomers used in the present invention include an aromatic dihydroxy compound represented by general formula (1), which has a conductivity of 5.0 μS / cm or less when formed into a slurry solution obtained by mixing a methanol solution containing the aromatic dihydroxy compound at a concentration of 30 mass % with pure water in an amount 9 times the mass of the methanol solution. [ka] In general formula (1), R1 and R2 each independently represent a hydrogen atom, a halogen atom, an optionally substituted or branched alkyl group having 1 to 20 carbon atoms, or an optionally substituted aryl group having 6 to 30 carbon atoms. R1 and R2 are Preferably, it is a hydrogen atom, an optionally substituted or branched alkyl group having 1 to 10 carbon atoms, or an optionally substituted aryl group having 6 to 16 carbon atoms, More preferably, it is a hydrogen atom, an optionally substituted or branched alkyl group having 1 to 6 carbon atoms, or an optionally substituted aryl group having 6 to 12 carbon atoms, Particularly preferred are a hydrogen atom, an optionally substituted or branched alkyl group having 1 to 3 carbon atoms, or an optionally substituted aryl group having 6 to 8 carbon atoms. Preferred examples of R1 and R2 include a hydrogen atom, a methyl group, an isopropyl group, a phenyl group, and a hydroxyphenyl group, with a hydrogen atom being particularly preferred. Examples of the substituent that may be substituted on the alkyl group or aryl group include a halogen atom and a hydroxyl group.

[0013] In general formula (1), m and n each independently represent an integer of 0 to 4. m and n are preferably integers of 0 to 2, more preferably each independently 0 or 1, and most preferably 0.

[0014] A preferred example of the aromatic dihydroxy compound represented by general formula (1) is one represented by the following general formula (1-1). [ka] In the general formula (1-1), R1, R2, m, and n are the same as those in the general formula (1).

[0015] Specific examples of the aromatic dihydroxy compound represented by the general formula (1) above include bis(4-hydroxyphenyl) ether [=DHDE], bis(4-hydroxy-3-methylphenyl) ether, bis(4-hydroxy-3,5-dimethylphenyl) ether, bis(4-hydroxy-3-t-butylphenyl) ether, bis(4-hydroxy-3-phenylphenyl) ether, bis(4-hydroxy-3-allylphenyl) ether, bis(4-hydroxy-3-ethylphenyl) ether, bis(4-hydroxy-3-sec-butylphenyl) ether, and bis(4-hydroxy-3-cumylphenyl) ether. Among these, bis(4-hydroxyphenyl) ether represented by the following formula (1-a) is particularly preferred. [ka] These aromatic dihydroxy compounds can be used alone or in combination of two or more. Of the aromatic dihydroxy compounds represented by the general formula (1), the aromatic dihydroxy compound represented by the formula (1-a) preferably accounts for 80 mol % or more, more preferably 90 mol % or more, and even more preferably 95 mol % to 100 mol %.

[0016] (b) Other raw material monomers (other aromatic dihydroxy compounds) As the other raw material monomers (other aromatic dihydroxy compounds), it is preferable to use an aromatic dihydroxy compound represented by the following general formula (2) in combination with the aromatic dihydroxy compound represented by general formula (1). [ka] (In the formula, R3 and R4 each independently represent hydrogen, fluorine, chlorine, bromine, iodine, an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 12 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, or an aralkyl group having 7 to 17 carbon atoms, each of which may have a substituent. p and q each independently represent an integer of 0 to 2. p and q each independently represent preferably 0 or 1, and more preferably 0. X is

[0017] [ka] wherein R5 and R6 each independently represent hydrogen, fluorine, chlorine, bromine, iodine, an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, or an aryl group having 6 to 12 carbon atoms, each of which may have a substituent, or R5 and R6 combine to form a carbocycle having 5 to 20 carbon atoms or a heterocycle having 5 to 12 atoms. R7 and R8 each independently represent hydrogen, fluorine, chlorine, bromine, iodine, an alkyl group having 1 to 9 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, or an aryl group having 6 to 12 carbon atoms, each of which may have a substituent. R9 is an alkylene group having 1 to 9 carbon atoms, which may have a substituent. b represents an integer of 0 to 20, and c represents an integer of 1 to 500.

[0018] Specific examples of the aromatic dihydroxy compound represented by general formula (2) include 4,4'-biphenyldiol, bis(4-hydroxyphenyl)methane, bis(2-hydroxyphenyl)methane, 2,4'-dihydroxydiphenylmethane, bis(4-hydroxyphenyl)sulfone, 2,4'-dihydroxydiphenylsulfone, bis(2-hydroxyphenyl)sulfone, bis(4-hydroxy-3-methylphenyl)sulfone, bis(4-hydroxyphenyl)sulfoxide, bis(4-hydroxyphenyl)sulfide, bis(4-hydroxyphenyl) 1,1-bis(4-hydroxyphenyl) ketone, 1,1-bis(4-hydroxyphenyl) ethane, 1,1-bis(4-hydroxyphenyl)-1-phenylethane, bis(4-hydroxyphenyl) diphenylmethane, 2,2-bis(4-hydroxyphenyl) propane, 2,2-bis(4-hydroxy-3-methylphenyl) propane, 1,1-bis(4-hydroxy-3-methylphenyl) ethane, bis(4-hydroxy-3-methylphenyl) methane, 2,2-bis(4-hydroxy-3-t-butylphenyl) propane, 2,2-bis(4-hydroxyphenyl) butane, 1, 1-bis(4-hydroxyphenyl)cyclohexane, 1,1-bis(4-hydroxy-3-methylphenyl)cyclohexane, 1,1-bis(4-hydroxyphenyl)cycloundecane, 1,1-bis(4-hydroxyphenyl)cyclododecane, 2,2-bis(4-hydroxy-3-allylphenyl)propane, 3,3,5-trimethyl-1,1-bis(4-hydroxyphenyl)cyclohexane, 9,9-bis(4-hydroxy-3-ethylphenyl)fluorene, 9,9-bis(4-hydroxy-3-methylphenyl)fluorene, 9,9- Bis(4-hydroxyphenyl)fluorene, α,ω-bis[3-(o-hydroxyphenyl)propyl]polydimethyldiphenyl random copolymer siloxane, α,ω-bis[3-(o-hydroxyphenyl)propyl]polydimethylsiloxane, 4,4'-[1,4-phenylenebis(1-methylethylidene)]bisphenol, 4,4'-[1,3-phenylenebis(1-methylethylidene)]bisphenol, adamantane, 2,2-bis(4-hydroxyphenyl)butane, 1,1-bis(4-hydroxyphenyl)-2-ethylhexane, 1,Examples include 1-bis(4-hydroxyphenyl)-2-methylpropane, 2,2-bis(4-hydroxyphenyl)-4-methylpentane, 1,1-bis(4-hydroxyphenyl)decane, 1,3-bis(4-hydroxyphenyl)-5,7-dimethyladamantane, and 2,2-bis(4-hydroxyphenyl)hexafluoropropane. Two or more of these can be used in combination. Among these, 1,1-bis(4-hydroxyphenyl)cyclohexane, 2,2-bis(4-hydroxyphenyl)-4-methylpentane, and 2,2-bis(4-hydroxy-3-methylphenyl)propane are particularly preferred.

[0019] The polycarbonate resin of the present invention may be a homopolymer or a copolymer. For example, the amount of the aromatic dihydroxy compound represented by general formula (1) used is preferably 10 to 100 mol %, more preferably 20 to 80 mol %, and even more preferably 30 to 70 mol %, of the total aromatic dihydroxy compounds.

[0020] The amount of the aromatic dihydroxy compound represented by formula (2) used is preferably 0 to 90 mol %, more preferably 20 to 80 mol %, and even more preferably 30 to 70 mol % of the total aromatic dihydroxy compounds.

[0021] (c) Other raw material monomers (other than aromatic dihydroxy compounds) When a polycarbonate resin is produced by the interfacial polycondensation method, a carbonate-forming compound and a terminal blocking agent are also used as raw material monomers other than the above-mentioned aromatic dihydroxy compound.

[0022] The carbonate-forming compound is used to bond structural units derived from the aromatic dihydroxy compound and forms a carbonyl group (-C(=O)-) in the polymer chain of the polycarbonate resin. Examples of the carbonate-forming compound include phosgene and triphosgene, and phosgene is preferred.

[0023] The terminal terminator is used to terminate the polymerization reaction of the raw material monomers, forming a terminal group on the polymer chain of the polycarbonate resin. As the terminal terminator, a monohydric phenol is preferably used. Examples of the end-stopper include alkylphenols such as phenol, p-cresol, o-cresol, 2,4-xylenol, pt-butylphenol, o-allylphenol, p-allylphenol, p-hydroxystyrene, p-hydroxy-α-methylstyrene, p-propylphenol, p-cumylphenol, p-phenylphenol, o-phenylphenol, p-trifluoromethylphenol, p-nonylphenol, p-dodecylphenol, eugenol, amylphenol, hexylphenol, heptylphenol, octylphenol, nonylphenol, decylphenol, dodecylphenol, myristylphenol, palmitylphenol, stearylphenol, and behenylphenol, and alkyl esters of parahydroxybenzoic acid such as the methyl ester, ethyl ester, propyl ester, butyl ester, amyl ester, hexyl ester, and heptyl ester. Two or more of the above monohydric phenols can also be used in combination.

[0024] The amount of the terminal terminator used is determined appropriately depending on the target molecular weight of the polycarbonate resin, etc., but the molar ratio of the aromatic dihydroxy compound to the terminal terminator used is preferably in the range of 100:1 to 10:1, more preferably 50:1 to 15:1, and even more preferably 40:1 to 20:1, for example, 25:1.

[0025] Polycarbonate resins can also be produced by transesterification, which uses components other than aromatic dihydroxy compounds, such as a carbonic acid diester and a transesterification catalyst.

[0026] Examples of the carbonic acid diester include diphenyl carbonate, ditolyl carbonate, bis(chlorophenyl) carbonate, m-cresyl carbonate, dimethyl carbonate, diethyl carbonate, dibutyl carbonate, and dicyclohexyl carbonate. Among these, diphenyl carbonate is particularly preferred from the viewpoints of reactivity and purity. The carbonic acid diester is used in a molar ratio of 0.70 to 1.20, and particularly preferably 1.00 to 1.20, relative to the aromatic dihydroxy compound. By adjusting this molar ratio, the molecular weight of the polycarbonate resin can be controlled within a preferred range.

[0027] Examples of the transesterification catalyst include alkali metal compounds, alkaline earth metal compounds, and nitrogen-containing compounds. Examples of alkali metal compounds include organic acid salts, inorganic salts, oxides, hydroxides, hydrides, and alkoxides of alkali metals. From the viewpoints of catalytic effect, price, distribution volume, and effect on the color of the resin, sodium carbonate and sodium hydrogencarbonate are preferred. Examples of alkaline earth metal compounds include organic acid salts, inorganic salts, oxides, hydroxides, hydrides, and alkoxides of alkaline earth metal compounds. Examples of the nitrogen-containing compound include quaternary ammonium hydroxides and salts thereof, and amines.

[0028] As the transesterification catalyst, zinc, tin, zirconium, and lead salts are preferably used, and these may be used alone or in combination, or may be used in combination with the above-mentioned alkali metal compounds or alkaline earth metal compounds. Specific examples of the transesterification catalyst that can be used include sodium carbonate, sodium bicarbonate, cesium carbonate, zinc acetate, zinc benzoate, zinc 2-ethylhexanoate, tin(II) chloride, tin(IV) chloride, tin(II) acetate, tin(IV) acetate, dibutyltin dilaurate, dibutyltin oxide, dibutyltin dimethoxide, zirconium acetylacetonate, zirconium oxyacetate, zirconium tetrabutoxide, lead(II) acetate, lead(IV) acetate, zirconium acetate, and titanium tetrabutoxide. Of these, titanium tetrabutoxide, sodium carbonate, sodium bicarbonate, and cesium carbonate are preferred, with sodium bicarbonate and cesium carbonate being more preferred.

[0029] The total amount of transesterification catalyst used was 1 × 10 per mole of all dihydroxy compounds. -9 ~1×10 -3 Molar ratio, preferably 1 x 10 -7 ~1×10 -4 Used in molar ratios.

[0030] (d) Polycarbonate resin manufacturing method The method for producing a polycarbonate resin of the present invention includes a polymerization step of polymerizing an aromatic dihydroxy compound represented by the above-mentioned general formula (1), and the produced polycarbonate resin contains structural units derived from the aromatic dihydroxy compound represented by the general formula (1). In the polymerization process of the present invention, raw materials are used, which have a conductivity of 5.0 μS / cm or less when formed into a slurry solution obtained by mixing a methanol solution containing an aromatic dihydroxy compound represented by the general formula (1) at a concentration of 30 mass % with pure water in an amount 9 times the mass of the methanol solution.

[0031] The polycarbonate resin of the present invention can be produced by reacting a raw material monomer containing an aromatic dihydroxy compound represented by general formula (1) with a carbonate ester-forming compound. A known method used in producing a polycarbonate resin derived from bisphenol A, such as a direct reaction of an aromatic dihydroxy compound with phosgene (phosgene method) or a transesterification reaction of an aromatic dihydroxy compound with a bisarylcarbonate (transesterification method), can be used.

[0032] In the phosgene process, an aromatic dihydroxy compound represented by the general formula (1) or an aromatic dihydroxy compound represented by the general formula (1) and an aromatic dihydroxy compound represented by the general formula (2) are typically reacted with phosgene in the presence of an acid binder and a solvent. Examples of acid binders include pyridine and alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, and solvents such as methylene chloride and chloroform. Furthermore, catalysts such as tertiary amines (e.g., triethylamine) or quaternary ammonium salts (e.g., benzyltriethylammonium chloride) are preferably added to promote the condensation polymerization reaction. Furthermore, monofunctional compounds such as alkyl ester-substituted phenols (e.g., phenol, pt-butylphenol, p-cumylphenol, and n-butyl p-hydroxybenzoate) and long-chain alkyl-substituted phenols are preferably added as molecular weight regulators to regulate the degree of polymerization. Furthermore, small amounts of antioxidants (e.g., sodium sulfite, hydrosulfite) and branching agents (e.g., phloroglucin, isatin bisphenol) may also be added, if desired. The reaction temperature is usually 0 to 150°C, preferably 5 to 40°C. The reaction time varies depending on the reaction temperature, but is usually 0.5 minutes to 10 hours, preferably 1 minute to 2 hours. During the reaction, it is desirable to maintain the pH of the reaction system at 10 or higher.

[0033] On the other hand, in the transesterification method, an aromatic dihydroxy compound represented by the general formula (1) is mixed with a bisaryl carbonate and reacted at high temperature under reduced pressure. Examples of bisaryl carbonate include diphenyl carbonate, di-p-tolyl carbonate, phenyl-p-tolyl carbonate, di-p-chlorophenyl carbonate, and dinaphthyl carbonate. Two or more of these compounds can also be used in combination. The reaction is typically carried out at a temperature ranging from 150 to 350°C, preferably from 200 to 300°C, and the final pressure reduction is preferably 1 mmHg or less to distill off phenols derived from the bisaryl carbonate produced by the transesterification reaction. The reaction time varies depending on the reaction temperature and the degree of vacuum, but is typically about 1 to 24 hours. The reaction is preferably carried out under an inert gas atmosphere such as nitrogen or argon. If desired, a molecular weight modifier, antioxidant, or branching agent may be added.

[0034] The polycarbonate resin of the present invention preferably has an intrinsic viscosity of 0.2 to 2.0 dl / g, more preferably 0.3 to 1.5 dl / g, and even more preferably 0.4 to 1.0 dl / g, as measured by the method described below in accordance with JIS K7367-1.

[0035] The polycarbonate resin of the present invention preferably has a Hazen color number (APHA) of 30 or less when 4 g of the polycarbonate resin is dissolved in 25 ml of methylene chloride, more preferably 5 to 27, and particularly preferably 10 to 25. APHA can be measured in accordance with JIS K0071-1, as described in the Examples below. [Example]

[0036] Examples of the present invention will be shown below together with comparative examples to explain the details of the invention, but the present invention is not limited to these examples.

[0037] <apha> 25 mL of methylene chloride was added to 4 g of the polycarbonate resin and dissolved, and the Hazen unit color number (APHA) of the solution was determined by visual measurement in accordance with JIS K0071-1.

[0038] <DHDE Conductivity> 3 g of DHDE was dissolved in 7 g of commercially available special grade methanol, and while stirring with a magnetic stirrer, 90 g of pure water was added to precipitate DHDE, and the conductivity of the slurry solution was measured with a conductivity meter (HI8733N manufactured by Hanna Instruments Japan Co., Ltd.). The conductivity of the blank without using DHDE was 1.0 μS / cm.

[0039] <Limiting Viscosity> The limiting viscosity [η] in deciliters / gram of the obtained polycarbonate resin was determined as follows. In accordance with JIS K7367-1, for a methylene chloride solution of polycarbonate resin at 0.5 gram / deciliter, the falling time was measured at a temperature of 25 °C using an Ubbelohde capillary viscometer, and the limiting viscosity was determined using a Huggins constant of 0.45.

[0040] <DHDE Purity> Under the conditions of eluent (methanol / ultrapure water = 75% / 25%), ODS column (diameter 6 mm × 150 mm), detector UV280 nm, DHDE sample concentration 100 ppm (injection volume 20 μL with the same composition as the eluent), column temperature 30 °C, and flow rate 1 ml / min, taking the peak at about 3.5 minutes as the main peak, the purity was calculated from the quantitative value using liquid chromatography (Alliance HPLC manufactured by Waters Japan K.K.).

[0041] <Types of DHDE Used in Examples and Comparative Examples> Various commercially available DHDEs were obtained, and the DHDE purity and conductivity were measured. The results are shown in Table 1.

Table 1

[0042] Example 1 31.5 g (0.156 mol) of D-1, 42.0 g (0.157 mol) of 1,1-bis(4-hydroxyphenyl)cyclohexane (hereinafter abbreviated as "BPZ": manufactured by Honshu Chemical Industry Co., Ltd.), and 0.3 g of hydrosulfite were dissolved in 800 ml of 5 w / w% aqueous sodium hydroxide solution. 450 ml of methylene chloride was added to the mixture, and while stirring, 43 g of phosgene was then blown in over 40 minutes while maintaining the temperature at 15 to 20°C. After the phosgene injection was completed, 1.55 g of n-butyl p-hydroxybenzoate (hereinafter abbreviated as "POBB": manufactured by API Corporation) as a molecular weight regulator and 100 ml of a 9 w / w% aqueous sodium hydroxide solution were added and vigorously stirred to emulsify the reaction liquid. After emulsification, 0.6 ml of triethylamine was added, and the mixture was stirred at 19 to 25°C for approximately 40 minutes to allow polymerization. After polymerization was completed, the reaction mixture was separated into an aqueous phase and an organic phase. The organic phase was neutralized with phosphoric acid and repeatedly washed with water until the electrical conductivity of the aqueous phase reached 10 μS / cm or less. The resulting polymer solution was added dropwise to warm water maintained at 60°C, and the solvent was evaporated to obtain a white powdery precipitate. The resulting precipitate was filtered and dried at 120°C for 18 hours to obtain a polymer powder. The intrinsic viscosity of a 0.5 g / dl solution of this polymer in methylene chloride at 20°C was 0.63 dl / g. The obtained polymer was analyzed by infrared absorption spectroscopy, and the intrinsic viscosity was 1770 cm -1 Absorption due to carbonyl groups at a position near 1240 cm -1 Absorption due to ether bonds was observed in the vicinity, and it was confirmed that the resin was a polycarbonate resin having carbonate bonds (hereinafter abbreviated as "PC-1"). APHA measurement was carried out using the obtained PC-1.

[0043] Example 2 Polymerization was carried out in the same manner as in Example 1, except that D-2 (DHDE conductivity 2.7 μS / cm) was used instead of D-1, to obtain a polycarbonate resin (intrinsic viscosity: 0.64 dL / g, hereinafter abbreviated as "PC-2"). APHA measurement was carried out in the same manner as in Example 1 using the obtained PC-2.

[0044] Example 3 Polymerization was carried out in the same manner as in Example 1, except that D-3 (DHDE conductivity 1.5 μS / cm) was used instead of D-1, to obtain a polycarbonate resin (intrinsic viscosity: 0.64 dL / g, hereinafter abbreviated as "PC-3"). APHA measurement was carried out in the same manner as in Example 1 using the obtained PC-3.

[0045] Example 4 Polymerization was carried out in the same manner as in Example 1, except that D-1 was replaced with D-4 (DHDE conductivity 4.6 μS / cm) and POBB was changed to 0.693 g, to obtain a polycarbonate resin (intrinsic viscosity: 1.00 dL / g, hereinafter abbreviated as "PC-4"). APHA measurement was carried out in the same manner as in Example 1 using the obtained PC-4.

[0046] Example 5 The amount of D-1 was changed to 18.2 g (0.090 mol) and the amount of BPZ was changed to 36.4 g (0.136 mol), and further, 6.2 g (0.023 mol) of 2,2-bis(4-hydroxyphenyl)-4-methylpentane (hereinafter abbreviated as "MIBK", manufactured by Honshu Chemical Industry Co., Ltd.) and 0.3 g of hydrosulfite were dissolved in 840 ml of 3.9 w / w% aqueous sodium hydroxide solution. 540 ml of methylene chloride was added to the mixture, and while stirring, 35 g of phosgene was then blown in over about 30 minutes while maintaining the temperature at 15 to 20°C. After the phosgene injection was completed, 0.42 g of pt-butylphenol (hereinafter abbreviated as "PTBP": manufactured by DIC Corporation) as a molecular weight regulator and 140 ml of a 9 w / w% aqueous sodium hydroxide solution were added and stirred vigorously to emulsify the reaction liquid. After emulsification, 0.6 ml of triethylamine was added, and the mixture was stirred at 19 to 25°C for approximately 40 minutes to allow polymerization. Thereafter, purification, solidification, and drying were carried out in the same manner as in Example 1 to obtain a polycarbonate resin (intrinsic viscosity: 0.98 dl / g, hereinafter abbreviated as "PC-5"). APHA measurement was carried out in the same manner as in Example 1 using the obtained PC-5.

[0047] Example 6 27 g (0.134 mol) of D-1 was used, and 63.0 g (0.246 mol) of 2,2-bis(4-hydroxy-3-methylphenyl)propane (hereinafter abbreviated as "BPC", manufactured by Honshu Chemical Industry Co., Ltd.) was used instead of BPZ. Furthermore, 0.10 g of triethylbenzylammonium chloride and 0.3 g of hydrosulfite were dissolved in 750 ml of 6.6 w / w% aqueous sodium hydroxide solution. 360 ml of methylene chloride was added to the mixture, and while stirring, 54 g of phosgene was then blown in over about 40 minutes while maintaining the temperature at 15 to 20°C. After the phosgene injection was completed, 0.76 g of pt-butylphenol (hereinafter abbreviated as "PTBP": manufactured by DIC Corporation) as a molecular weight regulator and 100 ml of a 9 w / w% aqueous sodium hydroxide solution were added and stirred vigorously to emulsify the reaction liquid. After emulsification, 0.6 ml of triethylamine was added, and the mixture was stirred at 17 to 27°C for approximately 40 minutes to allow polymerization. Thereafter, purification, solidification, and drying were carried out in the same manner as in Example 1 to obtain a polycarbonate resin (intrinsic viscosity: 1.00 dl / g, hereinafter abbreviated as "PC-6"). APHA measurement was carried out in the same manner as in Example 1 using the obtained PC-6.

[0048] Comparative Example 1 Polymerization was carried out in the same manner as in Example 1, except that D-5 was used instead of D-1, to obtain a polycarbonate resin (intrinsic viscosity: 0.63 dL / g, hereinafter abbreviated as "PC-7"). APHA measurement was carried out in the same manner as in Example 1 using the obtained PC-7.

[0049] Comparative Example 2 Polymerization was carried out in the same manner as in Example 1, except that D-6 was used instead of D-1, to obtain a polycarbonate resin (intrinsic viscosity: 0.64 dl / g, hereinafter abbreviated as "PC-8"). APHA measurement was carried out in the same manner as in Example 1 using the obtained PC-8.

[0050] Comparative Example 3 Polymerization was carried out in the same manner as in Example 1, except that D-7 was used instead of D-1, to obtain a polycarbonate resin (intrinsic viscosity: 0.63 dL / g, hereinafter abbreviated as "PC-9"). APHA measurement was carried out in the same manner as in Example 1 using the obtained PC-9.

[0051] Comparative Example 4 Polymerization was carried out in the same manner as in Example 4, except that D-5 was used instead of D-4, to obtain a polycarbonate resin (intrinsic viscosity: 0.99 dL / g, hereinafter abbreviated as "PC-10"). APHA measurement was carried out in the same manner as in Example 1 using the obtained PC-10.

[0052] Comparative Example 5 Polymerization was carried out in the same manner as in Example 5, except that D-8 was used instead of D-1, to obtain a polycarbonate resin (intrinsic viscosity: 0.99 dL / g, hereinafter abbreviated as "PC-11"). APHA measurement was carried out in the same manner as in Example 1 using the obtained PC-11.

[0053] Comparative Example 6 Polymerization was carried out in the same manner as in Example 6, except that D-5 was used instead of D-1, to obtain a polycarbonate resin (intrinsic viscosity: 1.00 dl / g, hereinafter abbreviated as "PC-12"). APHA measurement was carried out in the same manner as in Example 1 using the obtained PC-12.

[0054] The intrinsic viscosity and APHA measurement results of the polycarbonate resins obtained in the examples and comparative examples are shown in Table 2.

[0055] [Table 2]

[0056] When the production method of the present invention is used, the polycarbonate resin obtained can be used in applications where color matching is important, such as binder resins for printing inks and optical lenses.< / apha>

Claims

[Claim 1] A method for producing a polycarbonate resin containing a structural unit derived from an aromatic dihydroxy compound represented by the following general formula (1), the method includes a step of polymerizing the aromatic dihydroxy compound represented by the general formula (1) using raw materials, the raw materials having a conductivity of 5.0 μS / cm or less when a methanol solution containing the aromatic dihydroxy compound represented by the general formula (1) at a concentration of 30 mass % is mixed with pure water in an amount 9 times by mass of the methanol solution; In the polymerization step, at least one monomer selected from the group consisting of 1,1-bis(4-hydroxyphenyl)cyclohexane, 2,2-bis(4-hydroxyphenyl)-4-methylpentane, and 2,2-bis(4-hydroxy-3-methylphenyl)propane is further used as a raw material monomer; the aromatic dihydroxy compound represented by the general formula (1) is bis(4-hydroxyphenyl) ether, The method for producing the polycarbonate resin as described above, wherein a solution obtained by dissolving 4 g of the polycarbonate resin in 25 ml of methylene chloride has a Hazen color number (APHA) of 30 or less. 【Chemistry 1】 (In general formula (1), R １ and R ２ each independently represents a hydrogen atom, a halogen atom, an optionally substituted or branched alkyl group having from 1 to 20 carbon atoms, or an optionally substituted aryl group having from 6 to 30 carbon atoms; m and n each independently represent an integer of 0 to 4.

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