Methods for producing bisphenol, methods for producing recycled polycarbonate resin, methods for producing carbon dioxide, methods for producing carbonic acid diester, methods for producing epoxy resin, and methods for producing epoxy resin cured products

Abstract

Provided are methods for producing bisphenols and the like using a chemical recycling method that is gentle, environmentally friendly, and capable of efficiently decomposing polycarbonate resins. Also provided are methods for producing recycled polycarbonate resins and the like using the aforementioned bisphenols and other useful substances. Also provided are methods for producing bisphenols by decomposing polycarbonate resins in the presence of aromatic monohydric alcohols, water, and catalysts. Also provided are methods for producing carbon dioxide by recovering carbon dioxide generated by the aforementioned bisphenol production method. Also provided are methods for producing carbonic acid diesters using the aforementioned carbonic acid diesters. Furthermore, provided are methods for producing recycled polycarbonate resins using the aforementioned bisphenols and / or the aforementioned carbonic acid diesters. Furthermore, provided are methods for producing epoxy resins and cured epoxy resins using the aforementioned bisphenols.

Description

Technical Field

[0001] The present invention relates to a method for producing bisphenol. More specifically, it relates to a method for producing bisphenol by decomposing a polycarbonate resin. Furthermore, it relates to a method for producing a recycled polycarbonate resin using the bisphenol obtained by the aforementioned method for producing bisphenol. Furthermore, the present invention relates to a method for producing carbon dioxide and a method for producing a carbonic acid diester by decomposing a polycarbonate resin. Furthermore, the present invention relates to a method for producing an epoxy resin and a method for producing a cured epoxy resin product. Background Art

[0002] Plastics are produced in large quantities not only in Japan but also around the world due to their simplicity, durability, and low cost. Since most of these plastics are used "once a day," they sometimes escape into the environment without proper treatment. Specifically, plastic waste flows from rivers into the sea, where it degrades due to waves and ultraviolet rays, becoming smaller than 5mm. This small plastic waste is called microplastics. These microplastics can be mistakenly eaten by animals and fish. As a result, plastic waste has a significant impact on the ecosystem and has been recognized as a global problem in recent years as the marine plastic problem. Polycarbonate resin, which is used in a wide range of fields due to its transparency, mechanical properties, flame retardancy, dimensional stability, and electrical properties, is no exception.

[0003] One of the recycling methods of polycarbonate resins is chemical recycling in which the polycarbonate resin is chemically decomposed to return it to bisphenol for reuse. Hydrolysis is known as one of the decomposition methods of polycarbonate resins.

[0004] As a hydrolysis method, a method of placing a polycarbonate resin and an alkaline aqueous solution in a pressure-resistant container and hydrolyzing the polycarbonate resin under high temperature and high pressure is known (Patent Document 1). In addition, a method of dissolving a polycarbonate resin in a chlorinated hydrocarbon solvent and adding an alkali metal hydroxide as an alkaline catalyst to hydrolyze the polycarbonate resin is also known (Patent Document 2).

[0005] Phenol decomposition is another known method for decomposing polycarbonate resins. For example, there is also known a method for producing diphenyl carbonate and bisphenol A by decomposing polycarbonate resins by phenol decomposition (Patent Documents 3 and 4).

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent Publication No. 40-16536

[0009] Patent Document 2: International Publication No. 2006 / 114893

[0010] Patent Document 3: Japanese Patent Application Laid-Open No. 7-196582

[0011] Patent Document 4: Japanese Patent Application Laid-Open No. 7-316280

[0012] Patent Document 5: Japanese Patent Application Laid-Open No. 2005-97568

[0013] Patent Document 6: Japanese Patent Application Laid-Open No. 2004-345883

[0014] Patent Document 7: Japanese Patent Application Laid-Open No. 2006-144023 Summary of the Invention

[0015] Problems to be solved by the invention

[0016] Chemical recycling of polycarbonate resins is important as one of the solutions to the problem of ocean plastics.

[0017] Water is used in the hydrolysis of polycarbonate resins. However, when the hydrolysis is performed at temperatures above 100°C (the boiling point of water at normal pressure), the vapor pressure of the water creates high-pressure conditions. For example, according to Example 1 of Patent Document 1, water is used to decompose the polycarbonate resin at 180-185°C, resulting in high-pressure conditions and the need for a pressure-resistant container. On the other hand, in methods for hydrolyzing polycarbonate resins at near room temperature, a chlorinated hydrocarbon solvent is used as a solvent to dissolve the polycarbonate resin. For example, according to Example 1 of Patent Document 2, dichloromethane is used as a solvent to hydrolyze the polycarbonate resin at 40°C. Chlorinated hydrocarbon solvents such as dichloromethane are flame-retardant compounds due to their chemical stability. Therefore, improper disposal at high temperatures can lead to the generation of dioxins.

[0018] In the phenololysis of polycarbonate resins, phenol is used to depolymerize the polycarbonate resin. However, due to the high boiling point of phenol, the phenololysis temperature may be set to 100°C or higher. For example, according to Example 1 of Patent Document 3, a polycarbonate resin is phenololyzed at 160°C using an amine as a catalyst to produce diphenyl carbonate and bisphenol A. However, purification of bisphenol A from the generated diphenyl carbonate requires distillation separation under strict vacuum conditions at high temperatures, requiring stringent conditions and complicating the purification operation.

[0019] As described above, conventional chemical recycling of polycarbonate resins requires conditions that impose a heavy environmental burden or are excessively harsh, and further improvements are required.

[0020] On the other hand, diphenyl carbonate, a raw material for polycarbonate resin, is produced from phosgene and phenol in the presence of an alkaline catalyst such as pyridine, neutralized with an alkaline aqueous solution, and then distilled (Patent Document 5). The neutralization wastewater discharged during the neutralization is treated in a wastewater treatment process and then treated with activated sludge. However, since a large amount of neutralization wastewater is discharged, there is a problem of a heavy burden on the activated sludge.

[0021] In addition, in the reaction of phosgene and phenol, in addition to diphenyl carbonate, hydrogen chloride is also produced as a by-product. After the hydrogen chloride generated together with diphenyl carbonate is once absorbed by water and becomes hydrochloric acid, this hydrochloric acid becomes stripped hydrogen chloride and 18% by mass hydrochloric acid in a stripping distillation tower. The stripped hydrogen chloride is converted into chlorine in the oxidation step of the next step (patent documentation 6). This 18% by mass hydrochloric acid contains a sulfur component. In order to avoid the system concentration of this sulfur component, a part is discarded as hydrochloric acid wastewater.

[0022] In addition, the phosgene as the raw material of diphenyl carbonate is that chlorine and carbon monoxide react and synthesize.According to patent documentation 7, the unliquefied gas that cannot liquefy when liquefying carries out harmless treatment with sodium hydroxide aqueous solution (caustic soda aqueous solution), after the phosgene (phosgene) comprised in the unliquefied gas is decomposed completely, is discharged into the atmosphere as waste gas.On safety, need to make phosgene be decomposed completely, therefore in the harmless treatment of unliquefied gas, use the high aqueous solution of a large amount of sodium hydroxide concentrations.The high a large amount of sodium hydroxide aqueous solutions of this concentration exist the problem of abandoning as sodium hydroxide wastewater.

[0023] From the perspective of reducing environmental burdens, there is also a demand for effective utilization of wastewater such as neutralization wastewater discharged during the production of diphenyl carbonate, hydrochloric acid wastewater discharged during the recovery of by-product hydrogen chloride, and sodium hydroxide wastewater discharged during the detoxification treatment of unliquefied gas generated during the production of phosgene.

[0024] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method for producing bisphenol by utilizing a chemical recycling method that is gentle, has little environmental burden, and can efficiently decompose polycarbonate resin.

[0025] Furthermore, an object of the present invention is to provide a method for producing a regenerated polycarbonate resin using the obtained bisphenol.

[0026] Another object of the present invention is to provide a method for producing carbon dioxide using the above-mentioned method for producing bisphenol, and a method for producing a carbonic acid diester using the obtained carbon dioxide.

[0027] Another object of the present invention is to provide a method for producing an epoxy resin and a method for producing an epoxy resin cured product using the obtained epoxy resin.

[0028] Solutions for solving problems

[0029] The present inventors have conducted intensive research to solve the above-mentioned problems and have discovered a method for decomposing a polycarbonate resin in the presence of an aromatic monohydric alcohol such as phenol or cresol, water, and a catalyst. Furthermore, they have discovered a method for producing bisphenol and carbon dioxide using the above-mentioned polycarbonate resin decomposition method. Furthermore, they have discovered a method for producing useful materials such as recycled polycarbonate resin using the obtained bisphenol or carbon dioxide.

[0030] That is, the present invention relates to the following technical solutions.

[0031] <1> A method for producing bisphenol, comprising decomposing a polycarbonate resin in the presence of an aromatic monohydric alcohol, water, and a catalyst.

[0032] <2> According to the aforementioned <1> In the method for producing bisphenol, the catalyst is any one selected from the group consisting of alkali metal hydroxides, alkali metal carbonates, alkylamines, nitrogen-containing heterocyclic compounds, and acids.

[0033] <3> According to the aforementioned <2> In the method for producing bisphenol, the alkali metal hydroxide is sodium hydroxide or potassium hydroxide.

[0034] <4> According to the aforementioned <2> In the method for producing bisphenol, the alkylamine is represented by the following formula (I).

[0035]

[0036] Where R A represents an alkyl group having 1 to 3 carbon atoms, R B ~R C Each independently represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.

[0037] <5> According to the aforementioned <2> or <4> In the method for producing bisphenol, the alkylamine is a tertiary amine.

[0038] <6> According to the aforementioned <2> In the method for producing bisphenol, the acid is any one selected from the group consisting of hydrochloric acid, sulfuric acid, phosphoric acid, and sulfonic acid.

[0039] <7> According to the aforementioned <1> In the method for producing bisphenol, the catalyst comprises a nitrogen-containing heterocyclic compound, and the polycarbonate resin is decomposed in the coexistence of the aromatic monohydric alcohol, the water, the catalyst, and an alkali metal chloride.

[0040] <8> According to the aforementioned <2> or <7> In the method for producing bisphenol, the nitrogen-containing heterocyclic compound is a pyridine.

[0041] <9> According to the aforementioned <7> In the method for producing bisphenol, the alkali metal chloride is sodium chloride.

[0042] <10> According to the aforementioned <1> ~ <9> The method for producing bisphenol according to any one of the preceding claims, wherein the reaction temperature for decomposing the polycarbonate resin is 110° C. or lower.

[0043] <11> According to the aforementioned <1> ~ <10> The method for producing bisphenol according to any one of the preceding claims, wherein the polycarbonate resin is decomposed in a slurry-like reaction liquid containing the polycarbonate resin, the aromatic monohydric alcohol, the water, and the catalyst.

[0044] <12> According to the aforementioned <1> ~ <11> The method for producing bisphenol according to any one of the preceding claims, wherein the mass ratio of the water to the aromatic monohydric alcohol is 0.001 to 10.

[0045] <13> According to the aforementioned <1> In the method for producing bisphenol, the catalyst includes hydrochloric acid, and the polycarbonate resin is decomposed in the coexistence of the aromatic monohydric alcohol, the water, the catalyst, and bromophenols.

[0046] <14> According to the aforementioned <1> In the method for producing bisphenol, the catalyst comprises sodium hydroxide, and the polycarbonate resin is decomposed in the coexistence of the aromatic monohydric alcohol, the water, the catalyst, and sodium chloride and / or carbon tetrachloride.

[0047] <15> According to the aforementioned <1> ~ <14> The method for producing bisphenol according to any one of the preceding claims, wherein the aromatic monohydric alcohol is any one selected from the group consisting of phenol, cresol, and xylenol.

[0048] <16> According to the aforementioned <1> ~ <15> The method for producing bisphenol according to any one of the preceding claims, wherein the bisphenol is 2,2-bis(4-hydroxyphenyl)propane.

[0049] <17> According to the aforementioned <1> or <7> The method for producing bisphenol, wherein, when producing diaryl carbonate by a method comprising the following steps (a1), (b1), (b2), and (b3), the neutralization wastewater removed in step (b1) is used for decomposing the polycarbonate resin.

[0050] Step (a1): a step of reacting phosgene and an aromatic monohydric alcohol in the presence of a nitrogen-containing heterocyclic compound to obtain a reaction solution containing a diaryl carbonate

[0051] Step (b1): neutralizing the reaction solution containing the diaryl carbonate obtained in step (a1) with an aqueous alkali metal hydroxide solution to separate the oil phase containing the aromatic diaryl carbonate and the aqueous phase containing the nitrogen-containing heterocyclic compound and the alkali metal chloride, and then removing the aqueous phase as neutralization wastewater.

[0052] Step (b2): a step of washing the oil phase obtained in step (b1) with water

[0053] Step (b3): ​​a step of obtaining diaryl carbonate from the oil phase after step (b2)

[0054] <18> According to the aforementioned <17> In the method for producing bisphenol, the alkali metal chloride in the step (b1) is sodium chloride, and the alkali metal hydroxide aqueous solution in the step (b1) is sodium hydroxide aqueous solution.

[0055] <19> According to the aforementioned <1> or <13> The method for producing bisphenol comprises the following steps (a1), (c1), (c2), and (c3) for producing diaryl carbonate and recovering by-produced hydrogen chloride, wherein the hydrochloric acid wastewater removed in step (c3) is used for decomposing the polycarbonate resin.

[0056] Step (a1): a step of reacting phosgene and an aromatic monohydric alcohol in the presence of a nitrogen-containing heterocyclic compound to obtain a reaction solution containing a diaryl carbonate

[0057] Step (c1): The step of supplying the hydrogen chloride produced as a by-product in step (a1) to an absorption tower and allowing it to be absorbed by water or dilute hydrochloric acid to obtain concentrated hydrochloric acid.

[0058] Step (c2): distilling concentrated hydrochloric acid in a stripping tower, recovering hydrogen chloride gas from the top of the tower, and recovering hydrochloric acid from the bottom of the tower

[0059] Step (c3): A step of removing a portion of the hydrochloric acid recovered from the bottom of the tower as hydrochloric acid wastewater from the system and circulating the remaining hydrochloric acid in the absorption tower of step (c1).

[0060] <20> According to the aforementioned <1> or <14> The method for producing bisphenol comprises the following steps (d1) to (d4) for producing phosgene and treating unliquefied gas, wherein the sodium hydroxide wastewater removed in step (d4) is used for decomposing the polycarbonate resin.

[0061] Step (d1): a step of obtaining phosgene gas from chlorine and carbon monoxide

[0062] Step (d2): Cooling the phosgene gas obtained in step (d1) to obtain liquefied phosgene

[0063] Step (d3): a step of contacting the circulating sodium hydroxide aqueous solution with the unliquefied gas in step (d2) to decompose and discharge the phosgene in the unliquefied gas.

[0064] Step (d4): a step of removing a portion of the circulating sodium hydroxide aqueous solution as sodium hydroxide wastewater

[0065] <21> A method for producing a recycled polycarbonate resin, wherein the method comprises: <1> ~ <20> A recycled polycarbonate resin is produced using a bisphenol raw material of bisphenol obtained by the method for producing bisphenol described in any one of the above.

[0066] <22> A method for producing carbon dioxide, wherein the recovery of <1> ~ <20> Carbon dioxide generated by the method for producing bisphenol according to any one of the preceding claims.

[0067] <23> A method for producing a carbonic acid diester, wherein the method comprises: <22> Carbonic acid diester is produced by the carbon dioxide obtained by the carbon dioxide production method.

[0068] <24> According to the aforementioned <23> The method for producing a carbonic acid diester comprises the step of reacting carbon dioxide containing the carbon dioxide with an aliphatic monohydric alcohol.

[0069] <25> According to the aforementioned <23> The method for producing carbonic acid diester comprises the following steps: obtaining carbon monoxide from carbon dioxide containing the carbon dioxide and coke, reacting the obtained carbon monoxide with chlorine to obtain phosgene, and reacting the obtained phosgene with an aromatic monohydric alcohol to obtain the carbonic acid diester.

[0070] <26> A method for producing a recycled polycarbonate resin, wherein the method comprises: <23> ~ <25> A recycled polycarbonate resin is produced using a carbonate diester raw material of a carbonate diester obtained by the method for producing a carbonate diester as described above.

[0071] <27> A method for producing an epoxy resin, wherein the <1> ~ <20> An epoxy resin is produced using the bisphenol obtained by the method for producing bisphenol described in any one of the above.

[0072] <28> According to the aforementioned <27> The method for producing the epoxy resin further comprises reacting the epoxy resin with a polyvalent hydroxy compound raw material.

[0073] <29> A method for producing a cured epoxy resin, wherein the <27> or <28> The epoxy resin composition of the epoxy resin obtained by the epoxy resin production method and a curing agent is cured to obtain an epoxy resin cured product.

[0074] Effects of the Invention

[0075] According to the present invention, a method for producing bisphenol can be provided, which utilizes a chemical recycling method capable of efficiently decomposing polycarbonate resin under mild conditions with minimal environmental impact. Furthermore, the method for producing bisphenol of the present invention facilitates the recovery and purification of bisphenol.

[0076] Furthermore, the present invention can effectively utilize wastewater such as neutralization wastewater discharged during the production of diphenyl carbonate, hydrochloric acid wastewater discharged during the recovery of by-product hydrogen chloride, and sodium hydroxide wastewater discharged during the detoxification treatment of unliquefied gas generated during the production of phosgene.

[0077] Furthermore, according to the present invention, there is provided a method for producing a recycled polycarbonate resin using the obtained bisphenol.

[0078] Furthermore, the present invention can provide a method for producing carbon dioxide using the above-described method for producing bisphenol, and a method for producing a carbonic acid diester using the obtained carbon dioxide.

[0079] Furthermore, the present invention can provide a method for producing an epoxy resin and a method for producing an epoxy resin cured product using the obtained epoxy resin. BRIEF DESCRIPTION OF THE DRAWINGS

[0080] Figure 1 This is a flow chart for explaining an example of the method for producing bisphenol of the present invention using wastewater.

[0081] Figure 2 This is a flow chart for explaining an example of the method for producing bisphenol of the present invention using wastewater.

[0082] Figure 3 This is a flow chart for explaining an example of the method for producing bisphenol of the present invention using wastewater. DETAILED DESCRIPTION

[0083] The following describes an embodiment of the present invention in detail. However, the description of the constituent elements described below is an example of an embodiment of the present invention, and the present invention is not limited to the following description unless it exceeds the gist of the invention. It should be noted that when expressions such as "to" are used in this specification, they are used to include the numerical values ​​or physical property values ​​before and after them.

[0084] <Method for producing bisphenol>

[0085] The present invention relates to a method for producing bisphenol (hereinafter sometimes referred to as "the method for producing bisphenol of the present invention"), in which a polycarbonate resin is decomposed in the presence of an aromatic monohydric alcohol, water, and a catalyst.

[0086] The method for producing bisphenol of the present invention utilizes a chemical recycling method in which a polycarbonate resin is decomposed in the presence of an aromatic monohydric alcohol, water, and a catalyst.

[0087] The present inventors have discovered that by using an aromatic monohydric alcohol and water in combination in the presence of a catalyst, polycarbonate resin can be decomposed into bisphenol and carbon dioxide, and / or bisphenol salts and metal salts of carbonic acid, even under mild conditions around the boiling point of water (normal pressure, around 100°C). Furthermore, it has been found that even if a solvent with high solubility for polycarbonate resin, such as a halogen solvent, is not used to completely dissolve the polycarbonate resin, the decomposition reaction of the polycarbonate resin will occur at a high reaction rate by using an aromatic monohydric alcohol and water in combination. Furthermore, it has been found that the carbon dioxide and metal salts of carbonic acid generated by the decomposition of the polycarbonate resin are easily removed from the system, making the recovery and purification of bisphenol easier. The present invention is based on these findings.

[0088] By using an aromatic monoalcohol and water in combination, solvolysis (e.g., phenololysis) and hydrolysis reactions of the aromatic monoalcohol occur within the system, so that the polycarbonate resin is easily decomposed even under mild conditions. The diaryl carboxylic acid ester generated by the reaction of the polycarbonate resin and the aromatic monoalcohol is hydrolyzed to form carbon dioxide, which is easily discharged outside the system, thereby facilitating purification.

[0089] (Polycarbonate resin)

[0090] The polycarbonate resin used in the method for producing bisphenol of the present invention comprises a polymer composition having a carbonate bond (-OC(=O)-O-). Specifically, the polycarbonate resin used in the method for producing bisphenol of the present invention comprises a polymer having a bisphenol-derived structural unit represented by general formula (1).

[0091]

[0092] As R 1 ~R 4The substituents of each independently include a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, an aryl group, etc. For example, a hydrogen atom, a fluoro group, a chloro group, a bromo group, an iodo group, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, an n-pentyl group, an isopentyl group, an n-hexyl group, an n-heptyl group, an n-octyl group, an n-nonyl group, an n-decyl group, an n-undecyl group, an n-dodecyl group, a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, an isobutoxy group, a tert-butoxy group, an n-pentoxy group, an isopentyl group, an n-hexyl group, an n-heptyl group, an n-octyl group, an n-nonyl group, an n-decyl group, an n-undecyl group, an n-dodecyl group, a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, a cyclododecyl group, a benzyl group, a phenyl group, a tolyl group, and a 2,6-dimethylphenyl group can be mentioned.

[0093] As R 5 and R 6 The substituents of each independently include a hydrogen atom, an alkyl group, an alkoxy group, an aryl group, etc. For example, a hydrogen atom, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, an n-pentyl group, an isopentyl group, an n-hexyl group, an n-heptyl group, an n-octyl group, a 2-ethylhexyl group, an n-nonyl group, an n-decyl group, an n-undecyl group, an n-dodecyl group, a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, an isobutoxy group, a tert-butoxy group, an n-pentyl group, an isopentyl group, an n-hexyl group, an n-heptyl group, an n-octyl group, an n-nonyl group, an n-decyl group, an n-undecyl group, an n-dodecyl group, a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, a cyclododecyl group, a benzyl group, a phenyl group, a tolyl group, and a 2,6-dimethylphenyl group can be mentioned.

[0094] R 5 With R 6 Two groups may be bonded or cross-linked with each other. Examples include cyclopropylene, cyclobutylene, cyclopentylene, cyclohexylene, 3,3,5-trimethylcyclohexylene, cycloheptylene, cyclooctylene, cyclononylene, cyclodecylene, cycloundecylene, cyclododecylene, fluorenylene, xanthenylidene, and thioxanthenylidene.

[0095] Here, R in the above general formula (1) is used 1 ~R 4 is a hydrogen atom, and R 5 、R 6 A methyl group polycarbonate resin (hereinafter sometimes referred to as "bisphenol A type polycarbonate resin") is suitable as the raw material.

[0096] In the general formula (1), n ​​is not particularly limited and is, for example, 2 to 1,000.

[0097] Furthermore, the polycarbonate resin may be used not only as a single polycarbonate resin but also as a composition containing a resin other than the polycarbonate resin, such as a copolymer or a polymer alloy. Examples of compositions containing a resin other than the polycarbonate resin include polycarbonate / polyester copolymers, polycarbonate / polyester alloys, polycarbonate / polyacrylate copolymers, and polycarbonate / polyacrylate alloys. When using a composition containing a resin other than the polycarbonate resin, it is preferably one containing the polycarbonate resin as the main component (the composition containing 50% by mass or more of the polycarbonate resin).

[0098] The polycarbonate resin may be a mixture of two or more different polycarbonate resins. In addition, a single polycarbonate resin may be simply referred to as polycarbonate.

[0099] From the perspective of chemical recycling, the polycarbonate resin is preferably a polycarbonate resin contained in waste plastics. By stirring a reaction solution containing waste plastics containing polycarbonate resin, an aromatic monohydric alcohol, water, and a catalyst, the polycarbonate resin contained in the waste plastics can be decomposed to produce bisphenol or its salt.

[0100] Polycarbonate resin is processed into various molded products, such as optical components such as headlights and optical recording media such as optical discs. Waste plastics containing polycarbonate resin include scraps, defective products, and used molded products from the molding of polycarbonate resin into these molded products.

[0101] Waste plastics are suitable for cleaning, crushing, and pulverizing. Crushing methods include using a jaw crusher or rotary crusher to coarse crushing to pieces smaller than 20 cm; using a rotary crusher, cone crusher, or mill to medium crushing to pieces smaller than 1 cm; and using a mill to pulverize to pieces smaller than 1 mm. Any method is sufficient to reduce the size of the waste plastics to a size suitable for feeding into the decomposition tank. Thin waste plastics, such as those found on CDs and DVDs, can be cut using a pulverizer and fed into the decomposition tank. Alternatively, copolymers, polymer alloys, and other resins, such as the surface and back layers of optical discs, can be pre-removed from components other than polycarbonate resin.

[0102] (Aromatic monohydric alcohol)

[0103] One of the characteristics of the method for producing bisphenol of the present invention is the use of an aromatic monohydric alcohol. The aromatic monohydric alcohol is a compound in which one hydroxyl group is bonded to a carbon atom forming an aromatic ring, and is preferably any one selected from the group consisting of phenol, cresol, and xylenol.

[0104] Examples of cresol include o-cresol, m-cresol, p-cresol, and isomer mixtures containing one or more of these. Since a liquid at around 30° C. facilitates supply to a decomposition tank, o-cresol, m-cresol, an isomer mixture of m-cresol and p-cresol, or an isomer mixture of o-cresol, m-cresol, and p-cresol are preferred.

[0105] Examples of xylenol include 2,3-xylenol, 2,4-xylenol, 2,5-xylenol, 2,6-xylenol, 3,5-xylenol, 3,4-xylenol, and isomer mixtures containing one or more of these. 2,5-xylenol is preferred because it is industrially available at low cost.

[0106] If the mass ratio of the aromatic monohydric alcohol to the polycarbonate resin (mass of the aromatic monohydric alcohol / mass of the polycarbonate resin) is low, the amount of solid (polycarbonate resin) relative to the liquid increases, resulting in a higher slurry concentration and a tendency for poor mixing. Therefore, this mass ratio is preferably 0.01 or greater, more preferably 0.03 or greater, and even more preferably 0.05 or greater. Furthermore, if this mass ratio is high, the production efficiency of bisphenol and carbon dioxide tends to deteriorate. Therefore, this mass ratio is preferably 100 or less, more preferably 70 or less, and even more preferably 50 or less.

[0107] (water)

[0108] One of the characteristics of the bisphenol production method of the present invention is the use of water together with an aromatic monohydric alcohol. A low mass ratio of water to polycarbonate resin (mass of water / mass of polycarbonate resin) reduces the decomposition rate, resulting in prolonged decomposition time and reduced efficiency. Therefore, this mass ratio is preferably 0.1 or greater, more preferably 0.5 or greater, and even more preferably 1.0 or greater. Furthermore, a high mass ratio tends to reduce the production efficiency of bisphenol and carbon dioxide. Therefore, this mass ratio is preferably 100 or less, more preferably 70 or less, and even more preferably 50 or less.

[0109] The mass ratio of water to the aromatic monohydric alcohol (mass of water / mass of aromatic monohydric alcohol) is preferably 0.001 or greater, more preferably 0.05 or greater. Furthermore, this mass ratio is preferably 20 or less, more preferably 15 or less. This mass ratio may be 10 or less, 5 or less, 1 or less, 0.5 or less, 0.2 or less, or the like. A low mass ratio of water to the aromatic monohydric alcohol results in a reduced decomposition rate and prolonged decomposition time. A high mass ratio increases the volume of the reaction solution, resulting in reduced efficiency.

[0110] (catalyst)

[0111] One of the characteristics of the bisphenol production method of the present invention is the use of a catalyst. The catalyst may be any catalyst as long as it can promote the decomposition of the polycarbonate resin, and may be a base or an acid. The base is preferably at least one selected from the group consisting of alkali metal hydroxides, alkali metal carbonates, alkylamines, and nitrogen-containing heterocyclic compounds. Among these, any one selected from the group consisting of alkali metal hydroxides, alkali metal carbonates, alkylamines, nitrogen-containing heterocyclic compounds, and acids is preferred.

[0112] [Alkali metal hydroxide]

[0113] Alkali metal hydroxides are alkali metal ions (M + ) and hydroxide ions (OH - ) is a salt thereof, which is a compound represented by MOH (M represents an alkali metal atom). As the alkali metal hydroxide, sodium hydroxide or potassium hydroxide is preferred.

[0114] If the mass ratio of alkali metal hydroxide to polycarbonate resin (mass of alkali metal hydroxide / mass of polycarbonate resin) is low, the decomposition rate tends to slow, the decomposition time tends to be prolonged, and the efficiency tends to deteriorate. Therefore, this mass ratio is preferably 0.01 or greater, more preferably 0.1 or greater, and even more preferably 0.5 or greater. On the other hand, if this mass ratio is high, the amount of acid required for neutralization after decomposition tends to increase, thereby reducing the production efficiency of bisphenol and carbon dioxide. Therefore, this mass ratio is preferably 50 or less, more preferably 30 or less, and even more preferably 10 or less. Alternatively, this mass ratio may be 8 or less, 5 or less, 3 or less, and the like.

[0115] [Alkali metal carbonate]

[0116] Alkali metal carbonates are alkali metal ions (M + ) and carbonate ions (CO3 2- ) is a salt thereof, which is a compound represented by M2CO3 (M represents an alkali metal atom). As the alkali metal carbonate, sodium carbonate or potassium carbonate is preferred.

[0117] If the mass ratio of alkali metal carbonate to polycarbonate resin (mass of alkali metal carbonate / mass of polycarbonate resin) is low, the decomposition rate tends to slow, the decomposition time tends to be prolonged, and efficiency tends to deteriorate. Therefore, this mass ratio is preferably 0.01 or greater, more preferably 0.1 or greater, and even more preferably 0.5 or greater. Furthermore, if this mass ratio is high, the amount of acid required for post-decomposition neutralization tends to increase, thereby reducing the production efficiency of bisphenol and carbon dioxide. Therefore, this mass ratio is preferably 50 or less, more preferably 30 or less, and even more preferably 10 or less. Alternatively, this mass ratio may be 5 or less, 1 or less, 0.5 or less, and so on.

[0118] [Alkylamine]

[0119] Alkylamines are compounds in which at least one hydrogen atom of ammonia is substituted with an alkyl group. Among alkylamines, monoalkylamines, which are primary amines, react with the carbonate bond portion of the polycarbonate resin to form isocyanates. Therefore, dialkylamines, which are secondary amines, and trialkylamines, which are tertiary amines, are more preferred.

[0120] Since a dialkylamine as a secondary amine reacts with the carbonate bond portion of the polycarbonate resin to form a tetraalkylurea, a trialkylamine as a tertiary amine is more preferred.

[0121] The alkylamine preferably has a boiling point of 200°C or lower, more preferably 160°C or lower. At this boiling point, it can be removed along with aromatic monohydric alcohols such as phenol by reducing pressure and / or heating. However, if the boiling point is too low, the alkylamine may volatilize during the decomposition reaction, reducing the decomposition rate. Therefore, the boiling point of the alkylamine is preferably 10°C or higher, more preferably 30°C or higher.

[0122] The alkylamine is preferably an alkylamine represented by general formula (I).

[0123]

[0124] In formula (I), R A represents an alkyl group having 1 to 3 carbon atoms, R B ~R C Each independently represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.

[0125] R A Preferably methyl, ethyl, n-propyl, or isopropyl, R B ~R C A hydrogen atom, a methyl group, an ethyl group, an n-propyl group, or an isopropyl group is each independently preferred.

[0126] Specific examples of the alkylamine represented by the general formula (I) include methylamine, ethylamine, propylamine, dimethylamine, diethylamine, trimethylamine, and diethylamine.

[0127] If the mass ratio of the alkylamine to the polycarbonate resin (mass of the alkylamine / mass of the polycarbonate resin) is low, the decomposition rate decreases, resulting in a prolonged decomposition time and a tendency for poor efficiency. Therefore, this mass ratio is preferably 0.001 or greater, more preferably 0.005 or greater, and even more preferably 0.01 or greater. If this mass ratio is high, excess alkylamine inhibits the reaction to generate carbon dioxide. Therefore, this mass ratio is preferably 50 or less, more preferably 20 or less, and even more preferably 10 or less. Alternatively, this mass ratio may be 5 or less, 1 or less, 0.5 or less, or the like.

[0128] [Nitrogen-containing heterocyclic compounds]

[0129] A nitrogen-containing heterocyclic compound is a compound containing at least one nitrogen atom as an atom forming a heterocyclic ring. It may be a monocyclic compound or a polycyclic compound formed by condensing with other aromatic heterocyclic rings or aromatic carbocyclic rings. In addition, the ring may contain heteroatoms other than nitrogen (sulfur atoms, oxygen atoms, or second nitrogen atoms). Examples of nitrogen-containing heterocyclic compounds include six-membered ring compounds such as pyridines, pyrazines, and pyrimidines, five-membered ring compounds such as imidazoles, and polycyclic compounds such as quinolines, isoquinolines, and acridines.

[0130] Among them, the nitrogen-containing heterocyclic compound is preferably a pyridine. Pyridines are substituted or unsubstituted pyridines. Examples of substituents that may replace the hydrogen atoms of pyridine include alkyl groups, alkoxy groups, and hydroxyl groups. Preferably, the substituent is at least one selected from the group consisting of unsubstituted pyridine (C5H5N), picoline, methoxypyridine, and hydroxypyridine, and unsubstituted pyridine is more preferable.

[0131] If the mass ratio of the nitrogen-containing heterocyclic compound to the polycarbonate resin (mass of the nitrogen-containing heterocyclic compound / mass of the polycarbonate resin) is low, the decomposition rate decreases, resulting in a prolonged decomposition time and a tendency for reduced efficiency. Therefore, this mass ratio is preferably 0.0001 or greater, more preferably 0.0005 or greater, and even more preferably 0.001 or greater. Furthermore, if this mass ratio is high, an excess of the nitrogen-containing heterocyclic compound inhibits the carbon dioxide generation reaction. Therefore, this mass ratio is preferably 100 or less, more preferably 50 or less, and even more preferably 10 or less.

[0132] [acid]

[0133] Examples of the acid include inorganic acids such as hydrochloric acid, sulfuric acid, and phosphoric acid, and organic acids such as carboxylic acid and sulfonic acid.

[0134] The acid is preferably any one selected from the group consisting of hydrochloric acid, sulfuric acid, phosphoric acid, and sulfonic acid. The sulfonic acid includes alkylsulfonic acids such as methanesulfonic acid and aromatic sulfonic acids such as toluenesulfonic acid.

[0135] If the mass ratio of the acid to the polycarbonate resin (mass of the acid / mass of the polycarbonate resin) is low, the decomposition rate decreases, resulting in a prolonged decomposition time and a tendency for reduced efficiency. Therefore, this mass ratio is preferably 0.01 or greater, more preferably 0.05 or greater, and even more preferably 0.1 or greater. Furthermore, if this mass ratio is high, the amount of base required for neutralization tends to increase. Therefore, this mass ratio is preferably 20 or less, more preferably 10 or less, and even more preferably 5 or less.

[0136] (Preparation of reaction solution)

[0137] By stirring a reaction solution containing a polycarbonate resin, an aromatic monohydric alcohol, water, and a catalyst, the polycarbonate resin can be decomposed to produce bisphenol or its salt. Even if the polycarbonate resin is not completely dissolved, the decomposition reaction of the polycarbonate resin proceeds by combining the aromatic monohydric alcohol and water. Therefore, the prepared reaction solution can be a slurry-like reaction solution (a reaction solution in which the polycarbonate resin is dispersed in a liquid).

[0138] The slurry concentration in the reaction solution (mass of solid content in the reaction solution / mass of the reaction solution) is preferably 0.01 or higher, more preferably 0.05 or higher. Furthermore, it is preferably 0.5 or lower, more preferably 0.3 or lower. If the slurry concentration (solid content concentration) is too low, the decomposition efficiency decreases, while if the slurry concentration is too high, poor mixing is likely to occur.

[0139] The liquid component in the prepared reaction liquid contains aromatic monohydric alcohol and water as main components, and the total mass of the aromatic monohydric alcohol and water relative to the mass of the entire liquid component is 0.8 or more, 0.9 or more, 0.95 or more, etc.

[0140] The reaction solution is preferably prepared at 10°C or higher, more preferably 20°C or higher. Furthermore, the reaction solution is preferably prepared at 40°C or lower, more preferably 35°C or lower. If the temperature during reaction solution preparation is too low, the aromatic monohydric alcohol may easily solidify, causing poor mixing and sometimes making uniform mixing difficult, depending on the type of aromatic monohydric alcohol. Furthermore, if the temperature during reaction solution preparation is too high, the catalyst may volatilize, making it difficult to prepare the solution at the specified concentration, or causing the decomposition reaction to run away.

[0141] The order of mixing the polycarbonate resin, aromatic monohydric alcohol, water, and catalyst is not particularly limited. For example, the aromatic monohydric alcohol, water, and catalyst may be added to the polycarbonate resin in that order, or the aromatic monohydric alcohol, water, and catalyst may be added to the polycarbonate resin in that order. For more uniform mixing, the polycarbonate resin is preferably added after the aromatic monohydric alcohol and / or water.

[0142] As described above, the decomposition reaction of the polycarbonate resin is carried out in the presence of an aromatic monohydric alcohol, water, and a catalyst. However, as long as this does not hinder the purpose of the present invention, the polycarbonate resin may be decomposed in the presence of components other than the aromatic monohydric alcohol, water, and catalyst. In this case, it is also preferred to disperse the polycarbonate resin in a uniform solvent containing the aromatic monohydric alcohol, water, catalyst, and other components to carry out the decomposition reaction. Examples of components that may be present include alkali metal chlorides, bromophenols, and carbon tetrachloride.

[0143] Alkali metal chlorides are alkali metal ions (M + ) and chloride ions (Cl -), is a salt of MCl (M represents an alkali metal atom). Specifically, sodium chloride, potassium chloride, etc. can be mentioned, preferably sodium chloride. The amount of alkali metal chloride is not particularly limited. If it is too much, there is a concern that it will precipitate and thus form scale. Therefore, the mass ratio of alkali metal chloride to water (mass of alkali metal chloride / mass of water) is preferably 0.2 or less, more preferably 0.1 or less. In addition, if it is too little, the effect of adding alkali metal chloride sometimes becomes weak. In addition, when wastewater is used, dilution is required, and a large amount of water is used, thereby increasing the burden of wastewater treatment. Therefore, the mass ratio of alkali metal chloride to water is preferably 0.00001 or more, more preferably 0.0001 or more.

[0144] Bromophenols are compounds having one hydroxyl group bonded to the carbon forming an aromatic ring and one or two bromine atoms bonded thereto. In addition, bromophenols may have substituents other than hydroxyl groups and bromine atoms. Preferred are monobromophenol and / or dibromophenol. The amount of bromophenols is not particularly limited. If it is too much, there is a concern that the bromophenols may precipitate. Therefore, the mass ratio of bromophenols to water (mass of bromophenols / mass of water) is preferably 0.001 or less, more preferably 0.0001 or less. If it is too little, the effect of improving the efficiency of the decomposition reaction of the polycarbonate resin becomes weak. Therefore, the mass ratio of bromophenols to water is preferably 0.0000001 or more, more preferably 0.000001 or more.

[0145] The amount of carbon tetrachloride is not particularly limited. However, if it is too much, the reaction solution may undergo oil-water separation, which may prevent efficient decomposition of the polycarbonate resin. Therefore, the mass ratio of carbon tetrachloride to water (mass of carbon tetrachloride / mass of water) is preferably 0.0005 or less, more preferably 0.0001 or less. If it is too little, the effect of improving the efficiency of the decomposition reaction of the polycarbonate resin is weakened. Therefore, the mass ratio of carbon tetrachloride to water is preferably 0.0000001 or more, more preferably 0.000001 or more.

[0146] Specifically, when the catalyst contains a nitrogen-containing heterocyclic compound, the polycarbonate resin can be decomposed in the coexistence of an aromatic monohydric alcohol, water, the catalyst, and an alkali metal chloride (preferably sodium chloride). It is believed that the alkali metal chloride acts as a co-catalyst, thereby enabling more efficient decomposition of the polycarbonate resin.

[0147] When the catalyst contains hydrochloric acid, the polycarbonate resin can be decomposed in the coexistence of the aromatic monohydric alcohol, water, the catalyst, and the bromophenol. It is believed that the bromophenol acts as a co-catalyst, thereby enabling more efficient decomposition of the polycarbonate resin.

[0148] When the catalyst contains sodium hydroxide, the polycarbonate resin can be decomposed in the coexistence of an aromatic monohydric alcohol, water, the catalyst, sodium chloride, and / or carbon tetrachloride. The coexistence of sodium chloride and carbon tetrachloride is believed to allow more efficient decomposition of the polycarbonate resin.

[0149] Wastewater discharged during the production of diaryl carbonates, etc., can also be utilized in the preparation of the reaction solution. In particular, in the decomposition of a polycarbonate resin in the coexistence of an aromatic monohydric alcohol, water, a nitrogen-containing heterocyclic compound, and an alkali metal chloride, the decomposition of a polycarbonate resin in the coexistence of an aromatic monohydric alcohol, water, hydrochloric acid, and a bromophenol, and the decomposition of a polycarbonate resin in the coexistence of an aromatic monohydric alcohol, water, sodium hydroxide, sodium chloride, and carbon tetrachloride, the use of wastewater discharged from a production facility (plant) or the like, as described below, allows for simple preparation of the reaction solution and reduces environmental burden.

[0150] (Decomposition reaction)

[0151] The presence of an aromatic monohydric alcohol, water, and a catalyst cleaves the carbonate bonds of the polycarbonate resin, generating bisphenol and carbon dioxide, or a salt of bisphenol and a metal carbonate. The decomposition reaction can be clearly divided into two steps: preparing a reaction solution containing a polycarbonate resin, an aromatic monohydric alcohol, water, and a catalyst by controlling the concentration of the polycarbonate resin and the temperature of the reaction solution during preparation (in the mixture of the polycarbonate resin, the aromatic monohydric alcohol, water, and the catalyst) so that the decomposition reaction does not proceed; and decomposing the polycarbonate resin in the reaction solution. However, the steps of preparing the reaction solution and decomposing the polycarbonate resin can also be vaguely divided. The decomposition reaction of the polycarbonate resin is performed during the preparation of the reaction solution, preferably with a portion of the polycarbonate resin decomposed. By decomposing a portion of the polycarbonate resin during the preparation of the reaction solution, the decomposition reaction can proceed more efficiently.

[0152] The decomposition reaction may be carried out under normal pressure or under increased pressure. However, since the reaction proceeds sufficiently even under normal pressure, it is preferably carried out under normal pressure.

[0153] (Reaction temperature)

[0154] The steps from the preparation of the reaction solution to the cessation of the decomposition reaction can be carried out at the same temperature as that at which the reaction solution is prepared. Preferably, the temperature is raised to a predetermined reaction temperature after the reaction solution is prepared (after mixing the polycarbonate resin, aromatic monohydric alcohol, water, and catalyst). If the temperature during the preparation of the reaction solution is too high, there is a concern that the decomposition reaction may get out of control. By raising the temperature after the reaction solution is prepared, the decomposition reaction can be stably carried out, which is therefore preferred.

[0155] The reaction temperature is appropriately selected depending on the type of aromatic monohydric alcohol, reaction time, and other factors. At high temperatures, water in the reaction solution evaporates, halting hydrolysis. Furthermore, at low temperatures, the aromatic monohydric alcohol solidifies, becomes less susceptible to solvolysis, or the hydrolysis reaction rate decreases, prolonging the time required for decomposition. For these reasons, the reaction temperature is preferably 40°C or higher, and more preferably 50°C or higher, 60°C or higher, 70°C or higher, 75°C or higher, and 80°C or higher. Furthermore, the reaction temperature is preferably 110°C or lower, more preferably 100°C or lower, and even more preferably 95°C or lower.

[0156] In particular, the decomposition of the polycarbonate resin is preferably carried out at a reaction temperature of 40 to 110° C. and normal pressure, more preferably at a reaction temperature of 50 to 100° C. and normal pressure, and even more preferably at a reaction temperature of 60 to 95° C. and normal pressure.

[0157] It should be noted that when the reaction is conducted at the same temperature as that used to prepare the reaction solution, the reaction temperature is the average temperature from the time the polycarbonate resin, aromatic monohydric alcohol, water, and catalyst are mixed to the time the neutralization and distillation operations for stopping the decomposition reaction are initiated. Alternatively, when the reaction is conducted by heating the reaction solution after preparation, the reaction temperature is the average temperature from the time the reaction solution reaches the specified temperature to the time the neutralization and distillation operations for stopping the decomposition reaction are initiated.

[0158] (Reaction time)

[0159] The reaction time is appropriately selected depending on the slurry concentration, reaction temperature, and other factors. Long reaction times tend to decompose the generated bisphenol, so the reaction time is preferably 30 hours or less, more preferably 25 hours or less, and even more preferably 20 hours or less. Short reaction times may prevent the decomposition reaction from proceeding sufficiently, so the reaction time is preferably 0.1 hours or more, more preferably 0.5 hours or more, and even more preferably 1 hour or more.

[0160] The reaction time is defined as the time from the completion of mixing of the polycarbonate resin, aromatic monohydric alcohol, water, and catalyst to the start of neutralization and distillation to stop the decomposition reaction. The end point of the reaction time can be determined by tracking the decomposition reaction using liquid chromatography or the like.

[0161] (Method for stopping the decomposition reaction of polycarbonate resin)

[0162] The method for stopping the decomposition reaction of the polycarbonate resin is appropriately selected depending on the type of catalyst used. When using an alkali metal hydroxide, alkali metal carbonate, or acid as the catalyst, the decomposition reaction can be stopped by neutralization. Furthermore, when using an alkylamine or nitrogen-containing heterocyclic compound as the catalyst, the decomposition reaction can be stopped by distilling the alkylamine or nitrogen-containing heterocyclic compound and neutralizing it. In methods where an acid is supplied and then removed by neutralization, ammonium salts are generated, which also require removal. Therefore, distillation is preferably used to remove the alkylamine or nitrogen-containing heterocyclic compound.

[0163] (Bisphenol Recovery and Purification Method)

[0164] The recovery and purification of the resulting bisphenol can be carried out using conventional methods. For example, it can be recovered and purified by simple means such as crystallization and column chromatography. Specifically, after the decomposition reaction of the polycarbonate resin, the catalyst and solvent are removed, the organic solvent is mixed, and the resulting organic phase is washed with water or saline solution, and then neutralized and washed with ammonium chloride solution, if necessary. The washed organic phase is then cooled to allow crystallization.

[0165] As the organic solvent, aromatic hydrocarbons such as toluene, xylene, ethylbenzene, diethylbenzene, isopropylbenzene, and mesitylene; aliphatic hydrocarbons such as hexane, heptane, octane, nonane, decane, undecane, and dodecane; and aliphatic alcohols such as methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, tert-butanol, n-pentanol, isopentanol, n-hexanol, n-heptanol, n-octanol, n-nonanol, n-decanol, n-undecanol, n-dodecanol; and ethylene glycol, diethylene glycol, and triethylene glycol can be used.

[0166] It should be noted that the remaining aromatic monohydric alcohol and organic solvent may be removed by distillation before crystallization. Furthermore, when bisphenol A crystallizes in the presence of phenol, it forms a eutectic with the phenol. When phenol is used to decompose a polycarbonate resin containing structural units derived from bisphenol A, the phenol must be removed by distillation before crystallization to prevent the formation of a eutectic.

[0167] (Carbon dioxide recovery and purification method)

[0168] In the method for producing bisphenol of the present invention, the generated carbon dioxide can be recovered and purified. Carbon dioxide purification can be carried out by conventional methods. For example, physical absorption, chemical absorption, cryogenic separation, membrane separation, pressure swing adsorption, etc. can be used, and the method can be appropriately selected based on the impurities in the carbon dioxide generated during neutralization.

[0169] The method for producing bisphenol of the present invention will be described in more detail below, taking methods (A) to (C) for producing bisphenol A from a polycarbonate resin containing structural units derived from 2,2-bis(4-hydroxyphenyl)propane (bisphenol A) as examples.

[0170] <Method for producing bisphenol (A)>

[0171] The method (A) for producing bisphenol comprises: a step (A1) of decomposing a polycarbonate resin containing structural units derived from bisphenol A in a reaction solution comprising a polycarbonate resin, phenol, water, and an alkali metal hydroxide; a step (A2) of neutralizing the reaction solution after step (A1) to obtain an organic phase in which bisphenol A is dissolved; and a step (A3) of reducing the pressure and / or heating the organic phase obtained in step (A2) and then recovering the bisphenol A by crystallization. The method (A) for producing bisphenol is an example of the method for producing bisphenol of the present invention using phenol as the aromatic monohydric alcohol and an alkali metal hydroxide as the catalyst.

[0172] The main decomposition reaction proceeds according to the following reaction formula (2), and the main decomposition products obtained in step (A1) are alkali metal salts and alkali metal carbonates of bisphenol. It should be noted that n in the following reaction formula (2) is 2 to 1000.

[0173]

[0174] In the bisphenol production method (A), in order to generate bisphenol A from the alkali metal salt of bisphenol A and generate carbon dioxide from the alkali metal carbonate, the reaction liquid after step (A1) is neutralized to obtain an organic phase in which bisphenol A is dissolved (A2).

[0175] Neutralization is carried out by mixing an acid in the reaction solution. Examples of acids that can be used include hydrochloric acid, sulfuric acid, and phosphoric acid. Neutralization based on acid mixing can be carried out in a manner such that the pH of the reaction solution becomes less than 7, or in a manner such that it becomes greater than 7. However, if the pH is less than 7, there is a concern that the quality of the separated bisphenol A may be reduced. Therefore, the acid mixing is preferably carried out in a manner such that the pH of the reaction solution becomes greater than 7 (for example, pH 7.5 or above, pH 8.0 or above) as the end point. On the other hand, if the pH of the reaction solution is too high, bisphenol and carbon dioxide are not easily generated, so the acid mixing is carried out in a manner such that the pH becomes less than 10, and pH 9.5 or below is preferred.

[0176] Furthermore, by allowing the mixture of the reaction liquid and the acid to stand, oil-water separation can be achieved into an organic phase (phenol phase) in which the generated bisphenol A is dissolved, and an aqueous phase in which alkali metal hydroxides and the like (alkali metal hydroxides, acid added for neutralization, and salts generated by neutralization) are dissolved. If the aqueous phase is removed, the alkali metal hydroxides and the like can be removed.

[0177] Alternatively, an organic solvent such as an aromatic hydrocarbon may be added before or after the acid is mixed. After the acid and organic solvent are mixed in the reaction solution and neutralized, the oil-water separation is performed and the aqueous phase is removed to obtain an organic phase (a phase of phenol and the organic solvent) in which bisphenol A is dissolved. Adding an organic solvent facilitates oil-water separation, thereby making it easier to remove the aqueous phase in which alkali metal hydroxides and the like are dissolved.

[0178] In step (A3), the organic phase obtained in step (A2) is decompressed and / or heated, and then crystallized to recover bisphenol A. If phenol is present during crystallization, bisphenol A forms a cocrystal with phenol and precipitates. Therefore, in order to obtain bisphenol A, phenol is removed before crystallization in step (A3).

[0179] Specifically, the organic phase obtained in step (A2) is decompressed and / or heated to distill off liquid components such as phenol. Subsequently, an organic solvent such as an aromatic hydrocarbon is added to prepare a crystallization solution containing bisphenol A dissolved therein, which is then cooled to precipitate bisphenol A. The precipitated bisphenol A is recovered by solid-liquid separation.

[0180] Moreover, when using an alkali metal carbonate as a catalyst, it can also be implemented by the same method as the manufacturing method (A) of bisphenol.

[0181] <Method for producing bisphenol (B)>

[0182] Method (B) for producing bisphenol comprises: step (B1) of decomposing a polycarbonate resin containing structural units derived from bisphenol A in a reaction solution comprising a polycarbonate resin, phenol, water, and an alkylamine; and step (B2) of reducing the pressure and / or heating the reaction solution after step (B1), and then recovering bisphenol A by crystallization. Method (B) for producing bisphenol is an example of the method for producing bisphenol of the present invention using phenol as the aromatic monohydric alcohol and an alkylamine as the catalyst.

[0183] The main decomposition reaction proceeds according to the following reaction formula (3), and the main decomposition products obtained in step (B1) are bisphenol and carbon dioxide. It should be noted that n in the following reaction formula (3) is 2 to 1000.

[0184]

[0185] In the bisphenol production method (B), the reaction solution after step (B1) is depressurized and / or heated, followed by step (B2) of recovering bisphenol A by crystallization. Specifically, the reaction solution after step (B1) is depressurized and / or heated to distill off liquid components such as alkylamine and phenol. Subsequently, an organic solvent such as an aromatic hydrocarbon is added to prepare a crystallization solution containing bisphenol A, which is then cooled to precipitate bisphenol A. The precipitated bisphenol A is recovered by solid-liquid separation.

[0186] When an alkylamine is used as a catalyst, the alkylamine can be removed by adding an acid for neutralization. In this case, as in step (A2) of the bisphenol production method (A), an acid is mixed with the reaction liquid after the decomposition reaction for neutralization, followed by oil-water separation and removal of the aqueous phase to obtain an organic phase containing dissolved bisphenol A. Subsequently, as in step (A3) of the bisphenol production method (A), the obtained organic phase is depressurized and / or heated, and bisphenol A can be recovered by crystallization.

[0187] As such, methods for removing alkylamines from the decomposition reaction liquid of a polycarbonate resin include distillation and neutralization with acid. Neutralization with acid generates ammonium salts, which also require removal, so distillation is preferred. Using an alkylamine as a catalyst allows the alkylamine to be removed along with the phenol by reducing pressure and / or heating, eliminating the need for neutralization and simplifying purification.

[0188] When a nitrogen-containing heterocyclic compound is used as a catalyst, the reaction can be carried out by the same method as in the method for producing bisphenol (A) or the method for producing bisphenol (B).

[0189] <Method for producing bisphenol (C)>

[0190] The method (C) for producing bisphenol comprises: a step (C1) of decomposing a polycarbonate resin containing structural units derived from bisphenol A in a reaction solution containing a polycarbonate resin, phenol, water, and an acid; a step (C2) of neutralizing the reaction solution after step (C1) to obtain an organic phase in which bisphenol A is dissolved; and a step (C3) of reducing the pressure and / or heating the organic phase obtained in step (C2) and then recovering bisphenol A by crystallization. The method (C) for producing bisphenol is an example of the method for producing bisphenol of the present invention using phenol as the aromatic monohydric alcohol and an acid as the catalyst.

[0191] The main decomposition reaction proceeds according to the reaction formula (4) shown below. The main decomposition products obtained in step (C1) are bisphenol and carbon dioxide. It should be noted that n in the following reaction formula (4) has the same meaning as in the general formula (1). It should be noted that n in the following reaction formula (4) is 2 to 1000.

[0192]

[0193] In the bisphenol production method (C), after step (C1), step (C2) is performed to neutralize the reaction solution to obtain an organic phase in which bisphenol A is dissolved. Neutralization is performed by mixing a base into the reaction solution. Examples of the base used include sodium carbonate and sodium hydroxide.

[0194] Neutralization is preferably performed to terminate the reaction solution at a pH of greater than 7, similar to step (A2) of method (A) for producing bisphenol. For example, the base is preferably added to achieve a pH of 7.5 or higher, or 8.0 or higher. Alternatively, the base is preferably added to achieve a pH of 10 or lower, or 9.5 or lower.

[0195] In step (C2), similarly to step (A2) of method (A) for producing bisphenol, the mixture of the reaction liquid and the base, or the mixture of the reaction liquid, the base and the organic solvent, is subjected to oil-water separation, and the aqueous phase is removed to obtain an organic phase in which bisphenol A is dissolved.

[0196] In step (C3), bisphenol A is recovered from the organic phase obtained in step (C2) in which bisphenol A is dissolved. Bisphenol A can be recovered by crystallization after reducing the pressure and / or heating the organic phase obtained in step (C2), similarly to step (A3) of method (A) for producing bisphenol.

[0197] It should be noted that methods (A) to (C) for producing bisphenol are examples using phenol as the aromatic monohydric alcohol. When an aromatic monohydric alcohol other than phenol, such as cresol or xylenol, is used as the aromatic monohydric alcohol, bisphenol A does not form a eutectic. Therefore, the removal of the aromatic monohydric alcohol by reduced pressure and / or heating in steps (A3), (B2), and (C3) is not essential. In such cases, the organic phase obtained in steps (A2) and (C2) or the reaction solution after step (B1) can be cooled to precipitate bisphenol A and recover bisphenol A. By using cresol or xylenol, the purification of bisphenol A can be simplified.

[0198] Alternatively, bisphenol A can be recovered as a eutectic of bisphenol A and phenol. In this case, phenol is not distilled off, but the organic phase obtained in step (A2) and step (C2), or the reaction solution after step (B1), is cooled to precipitate the eutectic of bisphenol A and phenol and recover it.

[0199] As described above, the polycarbonate resin used in the method for producing bisphenol of the present invention is not limited to a polycarbonate resin containing structural units derived from bisphenol A. The method for producing bisphenol of the present invention using a polycarbonate resin containing structural units derived from a bisphenol other than bisphenol A can also be suitably carried out in the same manner as the above-mentioned methods (A) to (C) for producing bisphenol.

[0200] <Method for producing bisphenol using wastewater>

[0201] As described above, the bisphenol production method of the present invention can utilize wastewater discharged from diaryl carbonate production facilities during the preparation of the reaction solution. Utilizing wastewater allows for efficient use of wastewater, resulting in a production method with a lower environmental burden.

[0202] For example, neutralization wastewater discharged from a neutralization treatment facility in a diaryl carbonate production facility can be used to decompose polycarbonate resin. Generally, diaryl carbonate is produced by a method comprising the following steps (a1), (b1), (b2), and (b3), wherein step (b1) is a neutralization treatment.

[0203] Step (a1): a step of reacting phosgene and an aromatic monohydric alcohol in the presence of a nitrogen-containing heterocyclic compound to obtain a reaction solution containing a diaryl carbonate

[0204] Step (b1): neutralizing the reaction solution containing the diaryl carbonate obtained in step (a1) with an aqueous alkali metal hydroxide solution to separate the oil phase containing the aromatic diaryl carbonate and the aqueous phase containing the nitrogen-containing heterocyclic compound and the alkali metal chloride, and then removing the aqueous phase as neutralization wastewater.

[0205] Step (b2): a step of washing the oil phase obtained in step (b1) with water

[0206] Step (b3): ​​a step of obtaining diaryl carbonate from the oil phase after step (b2)

[0207] In the bisphenol production method of the present invention, the neutralization wastewater (aqueous phase) removed in step (b1) can be used to decompose the polycarbonate resin. Since the aromatic monohydric alcohol is contained not only in the oil phase but also in the aqueous phase, the neutralization wastewater discharged in step (b1) is water containing the aromatic monohydric alcohol, the nitrogen-containing heterocyclic compound, and the alkali metal chloride (neutralizing salt). Therefore, by mixing the polycarbonate resin with the neutralization wastewater discharged in step (b1), a reaction solution containing the polycarbonate resin, the aromatic monohydric alcohol, water, the nitrogen-containing heterocyclic compound, and the alkali metal chloride can be easily prepared.

[0208] In step (a1), the aromatic monohydric alcohol is the same as that used for decomposition of the polycarbonate resin. Preferably, the aromatic monohydric alcohol used for decomposition of the polycarbonate resin is the same as that used in step (a1). Furthermore, in step (a1), the nitrogen-containing heterocyclic compound is the same as that used for decomposition of the polycarbonate resin, preferably a pyridine.

[0209] In addition, the aqueous alkali metal hydroxide solution used in step (b1) is a solution obtained by dissolving alkali metal hydroxide in water. The alkali metal hydroxide is the same as the alkali metal hydroxide that can be used in the decomposition of polycarbonate resin. Step (b1) preferably adopts the following step: the reaction solution containing diaryl carbonate obtained in step (a1) is neutralized with an aqueous sodium hydroxide solution, and its oil and water are separated into an oil phase containing aromatic diaryl carbonate and an aqueous phase containing nitrogen-containing heterocyclic compound and sodium chloride, and the aforementioned aqueous phase is removed as neutralization wastewater. More preferably, the following step is adopted: the reaction solution containing diaryl carbonate obtained in step (a1) is neutralized with an aqueous sodium hydroxide solution, and its oil and water are separated into an oil phase containing aromatic diaryl carbonate and an aqueous phase containing pyridines and sodium chloride, and the aforementioned aqueous phase is removed as neutralization wastewater.

[0210] In addition, the hydrochloric acid wastewater discharged when recovering the by-product hydrogen chloride when manufacturing diaryl carbonate from phosgene and aromatic monohydric alcohol can be used for the decomposition of polycarbonate resin. For example, the hydrochloric acid wastewater discharged from the hydrogen chloride recovery equipment located in conjunction with the diaryl carbonate manufacturing facility can be utilized. Generally, the production of diaryl carbonate and the recovery of the by-product hydrogen chloride include the following steps (a1), step (c1), step (c2), and step (c3).

[0211] Step (a1): a step of reacting phosgene and an aromatic monohydric alcohol in the presence of a nitrogen-containing heterocyclic compound to obtain a reaction solution containing a diaryl carbonate

[0212] Step (c1): The step of supplying the hydrogen chloride produced as a by-product in step (a1) to an absorption tower and allowing it to be absorbed by water or dilute hydrochloric acid to obtain concentrated hydrochloric acid.

[0213] Step (c2): distilling concentrated hydrochloric acid in a stripping tower, recovering hydrogen chloride gas from the top of the tower, and recovering hydrochloric acid from the bottom of the tower

[0214] Step (c3): A step of removing a portion of the hydrochloric acid recovered from the bottom of the tower as hydrochloric acid wastewater from the system and circulating the remaining hydrochloric acid in the absorption tower of step (c1).

[0215] In the method for producing bisphenol of the present invention, the hydrochloric acid wastewater removed in step (c3) can be used to decompose the polycarbonate resin. The hydrochloric acid wastewater discharged in step (c3) contains a small amount of Cl-Br contained in the phosgene used as a raw material in step (a1) and bromophenols produced by a side reaction with the aromatic monohydric alcohol. Therefore, by mixing the polycarbonate resin, the aromatic monohydric alcohol, and the hydrochloric acid wastewater discharged in step (c3), a reaction solution containing the polycarbonate resin, the aromatic monohydric alcohol, water, hydrochloric acid, and bromophenols can be easily prepared.

[0216] Furthermore, sodium hydroxide wastewater discharged during the detoxification treatment of unliquefied gas generated during the production of phosgene, a raw material for diaryl carbonate, can be used to decompose polycarbonate resin. For example, sodium hydroxide wastewater discharged from an unliquefied gas detoxification tower (detoxification equipment) located in a phosgene production facility can be utilized. Typically, the production of phosgene and the treatment of unliquefied gas comprise the following steps (d1), (d2), (d3), and (d4).

[0217] Step (d1): a step of obtaining phosgene gas from chlorine and carbon monoxide

[0218] Step (d2): Cooling the phosgene gas obtained in step (d1) to obtain liquefied phosgene

[0219] Step (d3): a step of contacting the circulating sodium hydroxide aqueous solution with the unliquefied gas in step (d2) to decompose and discharge the phosgene in the unliquefied gas.

[0220] Step (d4): a step of removing a portion of the circulating sodium hydroxide aqueous solution as sodium hydroxide wastewater

[0221] In the method for producing bisphenol of the present invention, the sodium hydroxide wastewater removed in step (d4) can be used to decompose the polycarbonate resin. The sodium hydroxide wastewater discharged in step (d3) contains sodium chloride produced by neutralization and carbon tetrachloride as a byproduct. Therefore, by mixing the polycarbonate resin, an aromatic monohydric alcohol, and the sodium hydroxide wastewater discharged in step (d4), a reaction solution containing the polycarbonate resin, the aromatic monohydric alcohol, water, sodium hydroxide, sodium chloride, and carbon tetrachloride can be easily prepared.

[0222] Below, refer to Figures 1 to 3 Specific examples of methods (R1) to (R3) for producing bisphenol using wastewater are described.

[0223] <Method for producing bisphenol using wastewater (R1)>

[0224] Figure 1This is a flow chart for explaining an example of a method for producing bisphenol using neutralization wastewater discharged from a diphenyl carbonate production facility.

[0225] (Manufacture of diphenyl carbonate)

[0226] Figure 1 In the diphenyl carbonate production facility 1 shown, phosgene gas (CDC, G1) and phenol (PL) are first reacted in the presence of pyridine (PRD) in a DPC reactor 10 to produce a reaction liquid (L10) containing diphenyl carbonate (step (a1)). Hydrogen chloride gas (G10) produced as a byproduct is transferred from the upper portion of the DPC reactor 10 to an activated carbon column (not shown).

[0227] The reaction liquid (L10) containing diphenyl carbonate is transferred from the DPC reactor 10 to the dehydrochlorination tower 11 for dehydrochlorination. The hydrogen chloride gas (G12) generated in the dehydrochlorination tower 11 is transferred to an activated carbon tower (not shown) in the same manner as the hydrogen chloride gas (G10) produced as a by-product in the DPC reactor 10.

[0228] The reaction solution (L11) after dehydrochlorination is transported to a mixing tank 12 and then to a neutralization tank 13. In the neutralization tank 13, the hydrochloric acid that has not been completely removed from the dehydrochlorination tower 11 is neutralized with an aqueous sodium hydroxide solution (L12), and then the oil and water are separated. After the oil and water separation, the aqueous phase (L14) is discharged as neutralized wastewater, and the obtained oil phase (L13) is transported to a water washing tank 14 (step (b1)). It should be noted that the neutralized wastewater (aqueous phase (L14)) contains water, phenol, pyridine, and sodium chloride.

[0229] The oil phase (L13) is then washed with water (L15) in a water washing tank 14 (step (b2)). The oil phase (L13) and water (L15) fed to the water washing tank 14 are mixed, and the water phase (L17) is removed to obtain an oil phase (L16). The washed oil phase (L16) is sequentially fed to distillation towers 15 and 16 for distillation. Purified diphenyl carbonate (G13) is recovered from the top of distillation tower 16 (step (b3)).

[0230] (Manufacturing of bisphenol)

[0231] The aqueous phase (L14, neutralization wastewater) discharged from the neutralization tank 13 is transported to the decomposition tank 100 and mixed with the bisphenol A type polycarbonate resin (PC) to decompose the polycarbonate resin. In addition, the reaction liquid prepared in the decomposition tank 100 only needs to contain the aqueous phase (L14, neutralization wastewater) in at least a portion. Therefore, in addition to the aqueous phase (L14, neutralization wastewater), water (H2O) and phenol (PL) that are not neutralization wastewater (L14) can also be supplied to the decomposition tank 100 to decompose the polycarbonate resin. In addition, as a catalyst, an alkali (base) can also be supplied separately. By making it possible to supply water, phenol, and alkali, the ratio of water to phenol and the amount of catalyst can be appropriately adjusted. As the alkali supplied at this time, pyridine used as a catalyst in the manufacture of diphenyl carbonate is preferably used. The solution (L100) containing bisphenol A after the decomposition of PC is transported to the equipment for the next process such as distillation removal and neutralization of the catalyst to recover bisphenol A (not shown).

[0232] <Method for producing bisphenol using wastewater (R2)>

[0233] Figure 2 This is a flow chart for explaining an example of a method for producing bisphenol from hydrochloric acid wastewater discharged from a facility 2 for recovering hydrogen chloride produced as a by-product in the production of diphenyl carbonate.

[0234] (Chlorine Recovery)

[0235] The hydrogen chloride gas (G10, G12) produced as a by-product in the DPC reactor 10 is transported to the activated carbon tower 20, where organic impurities such as phenol are adsorbed and removed. The hydrogen chloride gas (G20) treated with activated carbon is transported to the absorption tower 21. The hydrogen chloride gas (G20) is absorbed by the water (L20) or dilute hydrochloric acid (L21, an unsaturated aqueous solution of hydrogen chloride) supplied to the absorption tower 21, and is discharged as concentrated hydrochloric acid (L23) and stored in the tank 22 (step (c1)). Next, it is transported to the stripping tower 23 for distillation, and high-purity hydrogen chloride gas (G21) is distilled from the top of the tower. In addition, the dilute hydrochloric acid (L24) is discharged from the bottom of the stripping tower 23 and stored in the tank 24 (step (c2)). To prevent the concentration of impurities, a certain amount of the dilute hydrochloric acid (L24) stored in tank 24 is discharged from tank 24 as hydrochloric acid wastewater (L25), and the remaining dilute hydrochloric acid (L26) is returned to absorption tower 21 (step (c3)). It should be noted that the hydrochloric acid wastewater (L25) contains water, hydrogen chloride, and bromophenols (monobromophenol and / or dibromophenol).

[0236] (Manufacturing of bisphenol)

[0237] The hydrochloric acid wastewater (L25) discharged from the tank 24 is transported to the decomposition tank 102, mixed with the bisphenol A type polycarbonate resin (PC) and phenol (PL) to decompose the polycarbonate resin. In addition, the reaction solution prepared in the decomposition tank 102 only needs to contain hydrochloric acid wastewater (L25) in part. Therefore, in addition to the hydrochloric acid wastewater (L25), water (H2O) other than the hydrochloric acid wastewater (L25) can also be supplied to the decomposition tank 102 to decompose the polycarbonate resin. In addition, as a catalyst, an acid (acid) can also be supplied separately. As the acid to be supplied additionally at this time, hydrochloric acid is preferably used. By making it possible to supply water and acid separately, the amount of catalyst can be appropriately adjusted. The solution (L102) containing bisphenol A after the decomposition of PC is transported to the equipment for the next process such as distillation removal and neutralization of the catalyst to recover bisphenol A (not shown).

[0238] <Method for producing bisphenol using wastewater (R3)>

[0239] Figure 3 This is a flow chart for explaining an example of a method for producing bisphenol using sodium hydroxide wastewater discharged from a detoxification tower 34 installed in a phosgene production facility 3 .

[0240] (Manufacturing of Phosgene and Treatment of Unliquefied Gas)

[0241] In the phosgene production facility 3, carbon monoxide gas (CO) and chlorine gas (CL2) are first supplied to a CDC reactor 30 filled with granular activated carbon (catalyst) to produce crude phosgene gas (G30) (step (d1)). The resulting crude phosgene gas (G30) is transported to a condenser 31, cooled with brine, and the liquefied phosgene (L30) is stored in a tank 32 (step (d2)). The phosgene (L30) stored in the tank 32 is evaporated by an evaporator 33 and used as phosgene gas (G1) in a diphenyl carbonate production facility, etc. (not shown).

[0242] In addition, the unliquefied gas (G31) that is not liquefied in the condenser 31 is supplied to the harm removal tower 34 in which the sodium hydroxide aqueous solution (L31) is circulated, and after the unliquefied gas (G31) is contacted with the sodium hydroxide aqueous solution (L31) and the phosgene in the unliquefied gas (G31) is decomposed, it is discharged into the atmosphere as waste gas (G32) (process (d3)). In addition, in the harm removal tower 34, in order to prevent the concentration of impurities, a part of the circulating sodium hydroxide (L31) is discharged as sodium hydroxide wastewater (L32) (process (d4)). It should be noted that the sodium hydroxide wastewater (L32) comprises water, sodium hydroxide, sodium chloride and carbon tetrachloride.

[0243] (Manufacturing of bisphenol)

[0244] The sodium hydroxide wastewater (L32) discharged from the harm removal tower 34 is transported to the decomposition tank 103, mixed with bisphenol A type polycarbonate resin (PC) and phenol (PL), and the polycarbonate resin is decomposed. In addition, the reaction solution prepared in the decomposition tank 103 only needs to contain sodium hydroxide wastewater (L32) in at least a portion. Therefore, in addition to the sodium hydroxide wastewater (L32), water (H2O) that is not sodium hydroxide wastewater (L32) can also be supplied to the decomposition tank 103 to decompose the polycarbonate resin. In addition, as a catalyst, an alkali (base) can also be supplied separately. As the alkali supplied in this case, sodium hydroxide is preferably used. By enabling the supply of water and catalyst separately, the amount of catalyst can be appropriately adjusted. The solution (L103) containing bisphenol A after PC decomposition is transported to the equipment for the next process such as distillation removal and neutralization of the catalyst to recover bisphenol A (not shown).

[0245] <Applications of Bisphenol>

[0246] The bisphenol obtained by the bisphenol production method of the present invention (hereinafter sometimes referred to as "regenerated bisphenol") can be used as a component, curing agent, additive, or precursor thereof for various thermoplastic resins such as polyether resins, polyester resins, polyacrylate resins, polycarbonate resins, polyurethane resins, and acrylic resins, and various thermosetting resins such as epoxy resins, unsaturated polyester resins, phenolic resins, polybenzoxazine resins, and cyanate resins, which are used in various applications such as optical materials, recording materials, insulating materials, transparent materials, electronic materials, adhesive materials, and heat-resistant materials. Furthermore, it is useful as an additive such as a developer for heat-sensitive recording materials, an anti-fading agent, a bactericide, and an antibacterial and antifungal agent.

[0247] Among these, in order to impart good mechanical properties, it is preferably used as a raw material (monomer) for thermoplastic resins and thermosetting resins, and more preferably as a raw material for polycarbonate resins and epoxy resins. In addition, it is also preferably used as a developer, and is particularly preferably used in combination with a leuco dye or a color change temperature adjuster.

[0248] <Method for producing carbon dioxide>

[0249] The present invention relates to a method for producing carbon dioxide (hereinafter sometimes referred to as "the method for producing carbon dioxide of the present invention") that reclaims the carbon dioxide generated by the method for producing bisphenol of the present invention. According to the method for producing carbon dioxide of the present invention, polycarbonate resin can be efficiently decomposed to obtain carbon dioxide under conditions that are mild and have a low environmental burden. As described above, in the method for producing bisphenol of the present invention, carbon dioxide is generated by the decomposition reaction of the polycarbonate resin and / or the neutralization after the decomposition reaction. This carbon dioxide can be recovered as a raw material for carbonic acid diesters such as dimethyl carbonate and diphenyl carbonate, a raw material for alkylene carbonates such as ethylene carbonate, a raw material for carbon monoxide, etc.

[0250] Specifically, when the catalyst used for the decomposition of the polycarbonate resin is a base, the method for producing carbon dioxide of the present invention may include: a step of decomposing the polycarbonate resin in the presence of an aromatic monohydric alcohol, water, and a base (catalyst); and a step of recovering the carbon dioxide generated by the decomposition of the polycarbonate resin.

[0251] In addition, when the catalyst used in the decomposition of the polycarbonate resin is an alkali, carbon dioxide is also generated during the neutralization after the decomposition reaction. Therefore, the method for producing carbon dioxide of the present invention preferably includes the following steps: a step of decomposing the polycarbonate resin in the presence of an aromatic monohydric alcohol, water and an alkali (catalyst); a step of neutralizing the reaction liquid obtained by decomposing the polycarbonate resin; and a step of recovering the carbon dioxide generated by the decomposition of the polycarbonate resin and / or the neutralization.

[0252] When the catalyst used for decomposition of the polycarbonate resin is an acid, the method for producing carbon dioxide of the present invention may include: a step of decomposing the polycarbonate resin in the presence of an aromatic monohydric alcohol, water, and an acid (catalyst); and a step of recovering the carbon dioxide generated by the decomposition of the polycarbonate resin.

[0253] As described above, carbon dioxide can be recovered by conventional methods, which can be appropriately selected according to other impurities. For example, physical absorption, chemical absorption, cryogenic separation, membrane separation, pressure swing adsorption, etc. can be applied.

[0254] <Method for producing carbonic acid diester>

[0255] The present invention relates to a method for producing carbonic acid diesters (hereinafter sometimes referred to as "the method for producing carbonic acid diesters of the present invention") using carbon dioxide obtained by the method for producing carbonic acid diesters of the present invention (hereinafter sometimes referred to as "regenerated carbon dioxide").

[0256] The manufacture method of carbonic acid diester of the present invention can utilize the manufacture method of known carbonic acid diester that is raw material with carbonic acid gas.In addition, as long as at least a portion of the carbonic acid gas of raw material uses regenerated carbonic acid gas, the content of the regenerated carbonic acid gas in the carbonic acid gas is not particularly limited.For example, the content of the regenerated carbonic acid gas in the carbonic acid gas is preferably more than 0.1 volume %, more preferably more than 0.5 volume %.

[0257] The carbonic acid diester production method of the present invention can produce dialkyl carbonates such as dimethyl carbonate, diaryl carbonates such as diphenyl carbonate, etc. The carbonic acid diester obtained by the carbonic acid diester production method of the present invention can be used as a raw material for polycarbonate resin, electrolyte solution, etc.

[0258] For example, the method for producing a carbonic acid diester of the present invention can utilize the method for producing a dialkyl carbonate described in the following (M1), the method for producing a diaryl carbonate described in the following (M2) or (M3), or the like.

[0259] (M1) Method for obtaining dialkyl carbonate by reacting carbon dioxide with aliphatic monohydric alcohol

[0260] (M2) A method of reacting carbon dioxide with an aliphatic monohydric alcohol to obtain a dialkyl carbonate, and reacting the obtained dialkyl carbonate with an aromatic monohydric alcohol to obtain a diaryl carbonate

[0261] (M3) A method of obtaining carbon monoxide from carbon dioxide and coke, reacting the obtained carbon monoxide with chlorine to obtain phosgene, and reacting the obtained phosgene with an aromatic monohydric alcohol to obtain a diaryl carbonate

[0262] Examples of the aliphatic monohydric alcohol include alcohols having 1 to 10 carbon atoms, preferably alcohols having 1 to 6 carbon atoms such as methanol, ethanol, propanol, isopropanol, butanol, pentanol, and hexanol, and more preferably methanol or butanol.

[0263] As the aromatic monohydric alcohol, the same aromatic monohydric alcohol as that used in the method for producing bisphenol of the present invention can be used, and phenol is preferred.

[0264] In addition, each reaction can be carried out in the presence of a known catalyst. Carbon dioxide and aliphatic monohydric alcohol can be reacted in the presence of a catalyst. As catalyst, known catalysts such as cerium oxide can be enumerated. As the catalyst used in the reaction of dialkyl carbonate and aromatic monohydric alcohol, for example, organic titanium catalysts such as tetraphenoxy titanium can be used.

[0265] Among them, as in (M1) or (M2) above, the method for producing a carbonic acid diester of the present invention preferably employs a method comprising a step of reacting carbon dioxide containing carbon dioxide obtained by the method for producing carbon dioxide of the present invention with an aliphatic monohydric alcohol.

[0266] <Method for producing recycled polycarbonate resin>

[0267] The method for producing a recycled polycarbonate resin of the present invention is a method for producing a recycled polycarbonate resin using a bisphenol raw material containing bisphenol (recycled bisphenol) obtained by the method for producing a bisphenol of the present invention and / or a carbonate diester raw material containing a carbonate diester obtained by the method for producing a carbonate diester of the present invention (hereinafter sometimes referred to as "recycled carbonate diester").

[0268] Hereinafter, the method for producing a recycled polycarbonate resin using a bisphenol raw material containing recycled bisphenol will be referred to as the "first method for producing a recycled polycarbonate resin," and the method for producing a recycled polycarbonate resin using a carbonate diester raw material containing a recycled carbonate diester will be referred to as the "second method for producing a recycled polycarbonate resin." Furthermore, the "first method for producing a recycled polycarbonate resin" and the "second method for producing a recycled polycarbonate resin" will be collectively referred to as the "method for producing a recycled polycarbonate resin of the present invention."

[0269] (Method for producing the first recycled polycarbonate resin)

[0270] The first method for producing a recycled polycarbonate resin is a method for producing a recycled polycarbonate resin using a bisphenol raw material comprising bisphenol (recycled bisphenol) obtained by the bisphenol production method of the present invention. The first method for producing a recycled polycarbonate resin utilizes a chemical recycling method in which the recycled bisphenol obtained by decomposing a polycarbonate resin contained in waste plastics, etc. into monomeric bisphenol is used as a raw material to produce the polycarbonate resin.

[0271] The recycled polycarbonate resin produced by the first method for producing a recycled polycarbonate resin can be produced using a known method for producing a polycarbonate resin using bisphenol as a raw material. For example, it can be produced by polymerizing a bisphenol raw material containing recycled bisphenol (a bisphenol obtained by decomposing a polycarbonate resin using the method for producing bisphenol of the present invention) with a carbonic acid diester raw material. The polymerization can be carried out by appropriately selecting a known method.

[0272] For example, the recycled polycarbonate resin can be produced by a method in which a bisphenol raw material including recycled bisphenol is subjected to an ester exchange reaction with a carbonic acid diester raw material such as diphenyl carbonate in the presence of an alkali metal compound and / or an alkaline earth metal compound.

[0273] Recycled bisphenol can be used as the entire bisphenol raw material, or it can be mixed with a non-recycled bisphenol and used as part of the bisphenol raw material. The amount of recycled bisphenol relative to the bisphenol raw material is not particularly limited, and may be any amount, such as 0.1% by mass or greater, 1% by mass or greater, 10% by mass or greater, 20% by mass or greater, 30% by mass or greater, 40% by mass or greater, 50% by mass or greater, 70% by mass or greater, 80% by mass or greater, or 90% by mass or greater. A higher proportion of recycled bisphenol improves environmental performance, and therefore, from an environmental perspective, a higher amount of recycled bisphenol relative to the bisphenol raw material is preferred.

[0274] The carbonic acid diester raw material may contain a regenerated carbonic acid diester, or may use only a general carbonic acid diester without containing a regenerated carbonic acid diester.

[0275] The above-mentioned transesterification reaction can be carried out by appropriately selecting a known method. An example of a method using diphenyl carbonate as a carbonic acid diester raw material will be described below.

[0276] In the above-described first method for producing a regenerated polycarbonate resin, diphenyl carbonate is preferably used in an excess amount relative to the bisphenol raw material. The amount of diphenyl carbonate used relative to the bisphenol raw material is preferably large, as the resulting regenerated polycarbonate resin has fewer terminal hydroxyl groups and exhibits excellent thermal stability. Furthermore, a small amount is preferably used, as the transesterification reaction is rapid and the desired molecular weight can be easily produced. Based on these considerations, the amount of diphenyl carbonate used relative to 1 mole of the bisphenol raw material is typically 1.001 moles or more, preferably 1.002 moles or more, and typically 1.3 moles or less, preferably 1.2 moles or less.

[0277] As a method for supplying the raw materials, the bisphenol raw material and diphenyl carbonate may be supplied in a solid form, but preferably one or both are melted and supplied in a liquid state.

[0278] When producing regenerated polycarbonate resin by transesterification reaction of diphenyl carbonate and bisphenol raw material, transesterification catalyst is usually used. As the transesterification catalyst, alkali metal compound and / or alkaline earth metal compound are preferably used. These can be used alone or in combination of two or more in any combination and ratio. It is practically desirable to use alkali metal compound.

[0279] The amount of catalyst used per 1 mol of the bisphenol raw material or diphenyl carbonate is usually 0.05 μmol or more, preferably 0.08 μmol or more, more preferably 0.10 μmol or more, and usually 100 μmol or less, preferably 50 μmol or less, more preferably 20 μmol or less.

[0280] By setting the amount of the catalyst within the above range, the polymerization activity required for producing a regenerated polycarbonate resin having a desired molecular weight can be easily obtained, and the polymer has excellent hue and does not undergo excessive polymer branching, making it easy to obtain a polycarbonate resin having excellent fluidity during molding.

[0281] When producing the regenerated polycarbonate resin by the above method, it is preferred that the two raw materials are continuously supplied to a raw material mixing tank, and the obtained mixture and the transesterification catalyst are continuously supplied to a polymerization tank.

[0282] In the production of recycled polycarbonate resin by the transesterification method, two raw materials supplied to a raw material mixing tank are generally uniformly stirred and then supplied to a polymerization tank containing a catalyst to produce a polymer.

[0283] (Method for producing the second recycled polycarbonate resin)

[0284] The second method for producing a regenerated polycarbonate resin is a method for producing a regenerated polycarbonate resin using a carbonic acid diester raw material comprising a carbonic acid diester (regenerated carbonic acid diester) obtained by the method for producing a carbonic acid diester of the present invention. The second method for producing a regenerated polycarbonate resin can be carried out by appropriately selecting a known polymerization method for polycarbonate resin, in addition to using a carbonic acid diester raw material comprising a regenerated carbonic acid diester. For example, a bisphenol raw material can be reacted with a carbonic acid diester raw material comprising a regenerated carbonic acid diester to produce a regenerated polycarbonate resin. The ratio of the bisphenol raw material to the carbonic acid diester raw material, the catalyst used, etc., in addition to using a carbonic acid diester raw material comprising a regenerated carbonic acid diester, are the same as those described in the method for producing the first regenerated polycarbonate resin.

[0285] Regeneration carbonic acid diester can be used as the whole of carbonic acid diester raw material, also can mix and use as the part of carbonic acid diester raw material with the general carbonic acid diester that is not regeneration carbonic acid diester.Regeneration carbonic acid diester is not particularly limited with respect to the amount of carbonic acid diester raw material, and more than 0.1 mass %, more than 1 mass %, more than 10 mass %, more than 20 mass %, more than 30 mass %, more than 40 mass %, more than 50 mass %, more than 70 mass %, more than 80 mass %, more than 90 mass % etc. are arbitrary.From the viewpoint of consideration to environment, regeneration carbonic acid diester is preferably more with respect to the amount of carbonic acid diester raw material.

[0286] The carbonate diester raw material in the second method for producing a regenerated polycarbonate resin is preferably a diaryl carbonate raw material containing diaryl carbonate obtained by the method for producing a carbonate diester of the present invention, and more preferably a diphenyl carbonate raw material containing diphenyl carbonate obtained by the method for producing a carbonate diester of the present invention.

[0287] When a carbonic acid diester raw material containing a regenerated carbonic acid diester is used, the bisphenol raw material may contain regenerated bisphenol, or only general bisphenol may be used without containing regenerated bisphenol.

[0288] (Recycled polycarbonate resin and composition thereof)

[0289] The recycled polycarbonate resin obtained by the method for producing a recycled polycarbonate resin of the present invention can be used directly, or a recycled polycarbonate resin composition comprising unused polycarbonate resin and recycled polycarbonate resin can be used. The recycled polycarbonate resin composition can be obtained by appropriately selecting a known mixing method, etc., and mixing unused polycarbonate resin and recycled polycarbonate resin. When using a recycled polycarbonate resin composition comprising unused polycarbonate resin and recycled polycarbonate resin, the amount of recycled polycarbonate resin is not particularly limited, and the greater the proportion of recycled polycarbonate resin, the better the environment. Therefore, from the perspective of environmental considerations, the amount of recycled polycarbonate resin relative to the amount of the recycled polycarbonate resin composition is preferably 50% by mass or more, and more preferably 70% by mass or more, 80% by mass or more, and 90% by mass or more.

[0290] The obtained recycled polycarbonate resin and composition can be molded into various molded products such as optical members and optical recording media in the same manner as virgin polycarbonate resin.

[0291] <Method for producing epoxy resin>

[0292] The present invention relates to a method for producing an epoxy resin using the bisphenol obtained by the method for producing bisphenol of the present invention. Alternatively, the obtained epoxy resin can be further reacted with a polyvalent hydroxy compound raw material to produce an epoxy resin.

[0293] Thus, the method for producing an epoxy resin of the present invention is a method for producing an epoxy resin using recycled bisphenol and / or an epoxy resin produced using recycled bisphenol as at least a portion of the raw materials. The method for producing an epoxy resin of the present invention is not particularly limited, except that recycled bisphenol (a bisphenol obtained by the method for producing bisphenol of the present invention) and / or an epoxy resin produced using recycled bisphenol is used as the raw material, and known methods for producing epoxy resins can be used. For example, as described later, recycled bisphenol can be used as at least a portion of the raw material for the polyvalent hydroxy compound when producing using a one-stage method, an oxidation method, or a two-stage method. The resulting epoxy resin can also be used as at least a portion of the raw material for an epoxy resin when producing using a two-stage method.

[0294] It should be noted that the "epoxy resin raw material" refers to an epoxy resin used as a raw material for the epoxy resin obtained by the epoxy resin production method of the present invention (hereinafter sometimes referred to as a "regenerated epoxy resin"). The "polyvalent hydroxy compound" is a general term for divalent or higher phenolic compounds and divalent or higher alcohol compounds, and the "polyvalent hydroxy compound raw material" refers to a polyvalent hydroxy compound used as a raw material for the regenerated epoxy resin.

[0295] As a method for producing the epoxy resin of the present invention, a one-stage method, an oxidation method, a two-stage method, etc. can be utilized.

[0296] The method for producing an epoxy resin by a one-stage process is a method for obtaining an epoxy resin by reacting a regenerated bisphenol (the bisphenol obtained by the method for producing a bisphenol of the present invention) with an epihalohydrin.

[0297] The production method of epoxy resin by oxidation is a method in which regenerated bisphenol is allylated using an allyl halide (allyl chloride, allyl bromide, etc.) and then subjected to an oxidation reaction to obtain the epoxy resin.

[0298] The two-step method for producing an epoxy resin is a method of reacting an epoxy resin raw material with a polyvalent hydroxy compound raw material, and uses recycled bisphenol and / or an epoxy resin produced using recycled bisphenol as a raw material.

[0299] Hereinafter, methods for producing epoxy resins by a one-stage method, an oxidation method, and a two-stage method will be described.

[0300] (Method for producing epoxy resin by one-stage process)

[0301] The method for producing the epoxy resin by the one-stage process is not particularly limited as long as it is a known production method, and will be described in detail below.

[0302] In the one-step method for producing an epoxy resin, a polyvalent hydroxy compound other than the recycled bisphenol (hereinafter sometimes referred to as "other polyvalent hydroxy compound") may be used in combination with the recycled bisphenol to produce the epoxy resin. Specifically, the one-step method for producing an epoxy resin is a method in which a polyvalent hydroxy compound raw material is reacted with an epihalohydrin to obtain the epoxy resin, and a method in which at least a portion of the polyvalent hydroxy compound raw material is recycled bisphenol can be employed.

[0303] The content of the recycled bisphenol in the polyvalent hydroxy compound raw material is not particularly limited. A high content of the recycled bisphenol is environmentally friendly, and therefore, it is preferably 1 to 100% by mass, more preferably 10 to 100% by mass.

[0304] Here, "other polyhydroxy compounds" is a general term for divalent or higher phenolic compounds and divalent or higher alcohol compounds other than recycled bisphenol. In the one-stage epoxy resin production method, the "polyhydroxy compound raw material" is the total polyhydroxy compound including recycled bisphenol and other polyhydroxy compounds used as needed.

[0305] Examples of other polyvalent hydroxy compounds include bisphenol A, tetramethylbisphenol A, bisphenol F, tetramethylbisphenol F, bisphenol S, bisphenol C, bisphenol AD, bisphenol AF, hydroquinone, resorcinol, methylresorcinol, biphenol, tetramethylbiphenol, dihydroxynaphthalene, dihydroxydiphenyl ether, thiodiphenols, phenol novolac resins, cresol novolac resins, phenol aralkyl resins, biphenyl aralkyl resins, naphthol aralkyl resins, terpene phenolic resins, dicyclopentadiene phenolic resins, bisphenol A novolac resins, naphthol novolac resins, brominated bisphenol A, brominated phenol novolac resins, and various polyvalent phenols such as benzaldehyde and hydroxyl radicals. Polyphenolic resins obtained by condensation reactions of various aldehydes such as benzaldehyde, crotonaldehyde, and glyoxal; polyphenolic resins obtained by condensation reactions of xylene resins and phenols; various phenolic resins such as co-condensation resins of heavy oil or asphalt, phenols, and formaldehyde; chain aliphatic diols such as ethylene glycol, trimethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, 1,3-pentanediol, 1,4-pentanediol, 1,5-pentanediol, and 1,6-hexanediol; cyclic aliphatic diols such as cyclohexanediol and cyclodecanediol; polyalkylene ether glycols such as polyethylene ether glycol, polyoxytrimethylene ether glycol, and polypropylene ether glycol; and the like.

[0306] When the reaction is carried out, the polyvalent hydroxy compound raw material is dissolved in epihalohydrin to prepare a uniform solution. As the epihalohydrin, epichlorohydrin or epibromohydrin can be generally used, and epichlorohydrin is preferred in the present invention.

[0307] The amount of epihalohydrin used is preferably 1.0 to 14.0 equivalents, particularly 2.0 to 10.0 equivalents, per equivalent of hydroxyl groups in the polyvalent hydroxy compound raw material (total polyvalent hydroxy compound). When the amount of epihalohydrin is greater than or equal to the lower limit, the molecular weight conversion reaction can be easily controlled, and the resulting epoxy resin can have an appropriate epoxy equivalent, which is preferred. On the other hand, when the amount of epihalohydrin is less than or equal to the upper limit, production efficiency tends to improve, which is also preferred.

[0308] Next, while stirring the above solution, an alkali metal hydroxide is added in the form of a solid or aqueous solution in an amount generally equivalent to 0.1 to 3.0 equivalents, preferably 0.8 to 2.0 equivalents, relative to 1 equivalent of the hydroxyl group of the polyvalent hydroxy compound raw material to carry out the reaction. When the amount of the alkali metal hydroxide added is above the above lower limit, the unreacted hydroxyl group and the generated epoxy resin are less likely to react, and the high molecular weight reaction is easily controlled, so it is preferred. In addition, when the amount of the alkali metal hydroxide added is below the above upper limit, impurities are less likely to be generated due to side reactions, so it is preferred. As the alkali metal hydroxide used here, sodium hydroxide or potassium hydroxide can generally be mentioned.

[0309] The reaction can be carried out under normal pressure or reduced pressure, and the reaction temperature is preferably 20 to 200°C, more preferably 40 to 150°C. A reaction temperature above the lower limit is preferred because the reaction proceeds easily and the reaction control is easy. A reaction temperature below the upper limit is preferred because side reactions are less likely to proceed, and in particular, the amount of polymerized product can be easily reduced.

[0310] In addition, the reaction is carried out while dehydrating as needed, using the following method: azeotroping the reaction solution while maintaining a specified temperature, cooling the volatile vapor to obtain a condensate to separate the oil / water, and returning the oil from which the water has been removed to the reaction system. To suppress a rapid reaction, the alkali metal hydroxide is preferably added intermittently or continuously over a period of 0.1 to 24 hours, more preferably over a period of 0.5 to 10 hours, in small amounts at a time. When the addition time of the alkali metal hydroxide is above the lower limit, it is preferred because it prevents the reaction from proceeding rapidly and makes it easier to control the reaction temperature. When the addition time is below the upper limit, it is preferred because it is easier to reduce the amount of polymer.

[0311] After the reaction is completed, the insoluble by-product salts can be removed by filtering or washing with water, and then the unreacted epihalohydrin can be removed by distillation by heating and / or distillation under reduced pressure.

[0312] In this reaction, catalysts such as quaternary ammonium salts such as tetramethylammonium chloride and tetraethylammonium bromide, tertiary amines such as benzyldimethylamine and 2,4,6-tris(dimethylaminomethyl)phenol, imidazoles such as 2-ethyl-4-methylimidazole and 2-phenylimidazole, phosphonium salts such as ethyltriphenylphosphonium iodide, and phosphines such as triphenylphosphine can also be used.

[0313] Furthermore, in this reaction, inert organic solvents such as alcohols such as ethanol and isopropanol, ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone, ethers such as dioxane and ethylene glycol dimethyl ether, glycol ethers such as methoxypropanol, and aprotic polar solvents such as dimethyl sulfoxide and dimethylformamide can also be used.

[0314] [Manufacturing of Epoxy Resin with Reduced Total Chlorine Content]

[0315] When it is necessary to reduce the total chlorine content of the epoxy resin obtained as described above, an epoxy resin having a reduced total chlorine content can be produced by reacting the epoxy resin with a base.

[0316] The reaction with the base can be performed using an organic solvent for dissolving the epoxy resin. The organic solvent used in the reaction is not particularly limited, but ketone-based organic solvents are preferably used from the perspectives of production efficiency, handling, and operability. Furthermore, aprotic polar solvents can be used to further reduce the amount of hydrolyzable chlorine.

[0317] Examples of ketone-based organic solvents include methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone. Methyl isobutyl ketone is particularly preferred due to its effectiveness and ease of post-processing. These can be used alone or in combination of two or more.

[0318] As aprotic polar solvent, for example, dimethyl sulfoxide, diethyl sulfoxide, dimethyl sulfone, sulfolane, dimethylformamide, dimethylacetamide, hexamethylphosphoramide etc. can be enumerated. These can be used alone or in combination with two or more. Among these aprotic polar solvents, dimethyl sulfoxide is preferred from the aspect of being easy to obtain and having excellent effect.

[0319] The amount of the solvent used is such that the concentration of the epoxy resin in the liquid subjected to the alkali treatment is generally 1 to 95% by mass, preferably 5 to 80% by mass.

[0320] As the base, a solid or solution of an alkali metal hydroxide can be used. Examples of the alkali metal hydroxide include potassium hydroxide and sodium hydroxide, preferably sodium hydroxide. In addition, the alkali metal hydroxide can be dissolved in an organic solvent or water. It is preferably used in the form of a solution obtained by dissolving the alkali metal hydroxide in an aqueous solvent or an organic solvent.

[0321] The amount of alkali metal hydroxide used, calculated as the solid content of the alkali metal hydroxide, is preferably 0.01 to 20.0 parts by mass per 100 parts by mass of the epoxy resin. More preferably, it is 0.10 to 10.0 parts by mass. If the amount of alkali metal hydroxide used is below the lower limit, the effect of reducing the total chlorine content is low. If the amount is above the upper limit, a large amount of polymer is produced, resulting in a reduced yield.

[0322] The reaction temperature is preferably 20 to 200°C, more preferably 40 to 150°C, and the reaction time is preferably 0.1 to 24 hours, more preferably 0.5 to 10 hours.

[0323] After the reaction, excess alkali metal hydroxide and by-product salts are removed by washing with water or the like, and the organic solvent can be removed by heating and / or distillation under reduced pressure and / or steam distillation.

[0324] (Method for producing epoxy resin by oxidation method)

[0325] The production method of the epoxy resin by oxidation is not particularly limited as long as it is a known production method. For example, it can be carried out according to the methods described in Japanese Patent Application Laid-Open Nos. 2011-225711, 2012-092247, and 2012-111858.

[0326] In the production of epoxy resins using an oxidation process, similar to the one-stage process, other polyhydric hydroxy compounds other than recycled bisphenol can be used in combination with the recycled bisphenol. Specifically, the production of epoxy resins using an oxidation process involves allylation of a polyhydric hydroxy compound starting material with an allyl halide, followed by an oxidation reaction to obtain the epoxy resin. In this process, at least a portion of the polyhydric hydroxy compound starting material can be recycled bisphenol.

[0327] In the production of epoxy resins using an oxidation process, the "polyhydroxy compound raw material" refers to the total amount of polyhydroxy compounds, including recycled bisphenol and other polyhydroxy compounds used as needed. Examples of other polyhydroxy compounds include the same compounds as those used in the one-stage process. The amount of recycled bisphenol in the polyhydroxy compound raw material is not particularly limited; however, a high recycled bisphenol content improves environmental performance, and therefore, is preferably 1 to 100% by mass, more preferably 10 to 100% by mass.

[0328] (Method for producing epoxy resin by two-step process)

[0329] The method for producing an epoxy resin by a two-step process is not particularly limited as long as it is a known production method, and will be described in detail below.

[0330] The two-stage method for producing an epoxy resin comprises a step of reacting an epoxy resin raw material with a polyvalent hydroxy compound raw material. A method in which at least a portion of the epoxy resin raw material is an epoxy resin produced using recycled bisphenol and / or a method in which at least a portion of the polyvalent hydroxy compound raw material is recycled bisphenol can be employed.

[0331] That is, the method for producing the epoxy resin by the two-step method may be any of the following methods (i) to (iii).

[0332] Method (i): A method of reacting an epoxy resin other than an epoxy resin produced using recycled bisphenol with a polyol raw material containing recycled bisphenol

[0333] In method (i), the epoxy resin raw material is an epoxy resin other than the epoxy resin produced using recycled bisphenol. In addition, the polyvalent hydroxy compound raw material is all polyvalent hydroxy compounds including recycled bisphenol and other polyvalent hydroxy compounds used as needed.

[0334] Method (ii): A method of reacting an epoxy resin raw material containing an epoxy resin produced using recycled bisphenol with a polyol raw material containing recycled bisphenol

[0335] In method (ii), the epoxy resin raw material is the total epoxy resin produced using recycled bisphenol and other epoxy resins used as needed. In addition, the polyhydroxy compound raw material is the total polyhydroxy compound produced using recycled bisphenol and other polyhydroxy compounds used as needed.

[0336] Method (iii): A method of reacting an epoxy resin raw material including an epoxy resin produced using recycled bisphenol with a polyvalent hydroxy compound other than recycled bisphenol

[0337] In method (iii), the epoxy resin raw material is the total epoxy resin including the epoxy resin produced using recycled bisphenol and other epoxy resins used as needed. The polyvalent hydroxy compound raw material is a polyvalent hydroxy compound other than recycled bisphenol.

[0338] The epoxy resin produced using recycled bisphenol used in methods (ii) and (iii) can be obtained by a method for producing an epoxy resin based on a one-stage process or a method for producing an epoxy resin based on an oxidation process. Alternatively, the epoxy resin obtained in method (i) can be used. It should be noted that epoxy resins other than the epoxy resin produced using recycled bisphenol are the same as the other epoxy resins described later in the method for producing a cured epoxy resin, and other polyvalent hydroxy compounds are the same as those in the one-stage process.

[0339] In methods (i) and (ii), the content of recycled bisphenol in the polyvalent hydroxy compound containing recycled bisphenol is not particularly limited. A high content of recycled bisphenol is environmentally friendly, and therefore, it is preferably 1 to 100% by mass, more preferably 10 to 100% by mass.

[0340] In addition, in method (ii) and method (ii), the content of the epoxy resin produced using recycled bisphenol in the epoxy resin raw material containing the epoxy resin produced using recycled bisphenol is not particularly limited. If the content of the epoxy resin produced using recycled bisphenol is high, it is better for the environment. Therefore, it is preferably 1 to 100% by mass, and more preferably 10 to 100% by mass.

[0341] In a two-stage reaction, the epoxy resin raw material and the polyvalent hydroxy compound raw material are preferably used in an equivalent ratio of (epoxy equivalent) to (hydroxy equivalent) of 1:0.1 to 2.0. More preferably, it is 1:0.2 to 1.2. This equivalent ratio within this range facilitates molecular weight increase and allows for a greater number of terminal epoxy groups to remain, making it a preferred method.

[0342] In addition, a catalyst can be used in the reaction based on the two-stage method. As its catalyst, any catalyst can be used as long as it has a compound with catalytic ability to make the reaction of the epoxy group and the phenolic hydroxyl group or the alcoholic hydroxyl group proceed. For example, alkali metal compounds, organophosphorus compounds, tertiary amines, quaternary ammonium salts, cyclic amines, imidazoles, etc. can be mentioned. Among these, quaternary ammonium salts are preferred. In addition, the catalyst can be used only one type or in combination of two or more types. The amount of the catalyst used is usually 0.001 to 10% by mass relative to the epoxy resin raw material.

[0343] In addition, in the reaction based on the two-stage method, a solvent can be used. As the solvent, any solvent can be used as long as the epoxy resin raw material is dissolved. For example, aromatic solvents, ketone solvents, amide solvents, glycol ether solvents, etc. can be mentioned. Only one solvent can be used, or two or more solvents can be used in combination. In addition, the resin concentration in the solvent is preferably 10 to 95% by mass. More preferably, it is 20 to 80% by mass. In addition, when a highly viscous product is generated during the reaction, a solvent can be added to continue the reaction. After the reaction is completed, the solvent can be removed as needed or further added.

[0344] In the two-stage reaction, the reaction temperature is preferably 20 to 250°C, more preferably 50 to 200°C. If the reaction temperature is above the upper limit, there is a concern that the produced epoxy resin may deteriorate. If the reaction temperature is below the lower limit, the reaction may not proceed sufficiently. The reaction time is generally 0.1 to 24 hours, preferably 0.5 to 12 hours.

[0345] <Method for producing cured epoxy resin>

[0346] The present invention relates to a method for producing a cured epoxy resin product, comprising curing an epoxy resin composition comprising an epoxy resin obtained by the method for producing an epoxy resin of the present invention and a curing agent to produce the cured epoxy resin product. In the method for producing a cured epoxy resin of the present invention, the epoxy resin obtained by the method for producing an epoxy resin of the present invention and a curing agent are mixed to produce a composition comprising the epoxy resin and the curing agent (hereinafter sometimes referred to as an "epoxy resin composition"), and then curing the epoxy resin composition to produce the cured epoxy resin product.

[0347] Furthermore, the epoxy resin composition may contain other epoxy resins other than the epoxy resin obtained by the epoxy resin production method of the present invention (hereinafter sometimes simply referred to as "other epoxy resins"), a curing agent, a curing accelerator, an inorganic filler, a coupling agent, and the like, as needed.

[0348] The content of the recycled epoxy resin in the epoxy resin composition is not particularly limited. If the content of the recycled epoxy resin is high, the environment is excellent. Therefore, relative to 100 parts by mass of the total epoxy resin components in the recycled epoxy resin composition, the recycled epoxy resin is preferably 40 parts by mass or more, more preferably 60 parts by mass or more. When other epoxy resins are included, the recycled epoxy resin can be set to 40 to 99 parts by mass, 60 to 99 parts by mass, etc. relative to 100 parts by mass of the total epoxy resin components in the epoxy resin composition. It should be noted that "total epoxy resin components" are equivalent to the amount of all epoxy resins contained in the epoxy resin composition, which is the total of the recycled epoxy resin and other epoxy resins used as needed.

[0349] (Curing Agent)

[0350] In the present invention, a curing agent refers to a substance that promotes the cross-linking reaction and / or chain extension reaction between epoxy groups in an epoxy resin. It should be noted that, in the present invention, even if generally referred to as a "curing accelerator," any substance that promotes the cross-linking reaction and / or chain extension reaction between epoxy groups in an epoxy resin is also considered a curing agent.

[0351] In the epoxy resin composition, the content of the curing agent is preferably 0.1 to 1000 parts by mass relative to 100 parts by mass of the total epoxy resin component, and more preferably 500 parts by mass or less.

[0352] As a curing agent, all curing agents commonly known as epoxy resin curing agents can be used without particular limitation. For example, amine curing agents such as phenolic curing agents, aliphatic amines, polyetheramines, alicyclic amines, aromatic amines, acid anhydride curing agents, amide curing agents, tertiary amines, imidazoles, etc. can be enumerated. A curing agent can be used alone or in combination with two or more. When two or more curing agents are used in combination, they can be pre-mixed to prepare a mixed curing agent and then used. Alternatively, when the epoxy resin obtained by the manufacture method of the epoxy resin of the present invention and the components of other epoxy resins are mixed, each component of the curing agent can be separately added and mixed simultaneously.

[0353] [Phenolic curing agent]

[0354] Specific examples of phenolic curing agents include recycled bisphenol, bisphenol A, tetramethyl bisphenol A, bisphenol F, tetramethyl bisphenol F, bisphenol C, bisphenol S, bisphenol AD, bisphenol AF, hydroquinone, resorcinol, methyl resorcinol, biphenol, tetramethyl biphenol, dihydroxynaphthalene, dihydroxydiphenyl ether, thiodiphenols, phenol novolac resin, cresol novolac resin, phenol aralkyl resin, biphenyl aralkyl resin, naphthol aralkyl resin, terpene phenolic resin, dicyclopentadiene phenolic resin, bisphenol A novolac resin, trisphenol methane type resin, naphthol novolac resin, brominated bisphenol A, brominated Various polyphenols such as chemical phenol novolac resins, polyphenol resins obtained by the condensation reaction of various phenols with various aldehydes such as benzaldehyde, hydroxybenzaldehyde, crotonaldehyde, and glyoxal, polyphenol resins obtained by the condensation reaction of xylene resins and phenols, co-condensation resins of heavy oils or asphalts with phenols and formaldehydes, phenol·benzaldehyde·xylylenedimethoxy condensates, phenol·benzaldehyde·xylylenedimethyl dihalide condensates, phenol·benzaldehyde·4,4'-dimethoxybiphenyl condensates, phenol·benzaldehyde·4,4'-dihalogenated biphenyl condensates, etc.

[0355] These phenolic curing agents may be used alone or in combination of two or more in any combination and blending ratio.

[0356] The amount of the phenolic curing agent added is preferably 0.1 to 1000 parts by mass, more preferably 500 parts by mass or less, based on 100 parts by mass of the total epoxy resin components in the epoxy resin composition.

[0357] [Amine curing agent]

[0358] Examples of the amine-based curing agent (excluding tertiary amines) include aliphatic amines, polyether amines, alicyclic amines, and aromatic amines.

[0359] Examples of the aliphatic amines include ethylenediamine, 1,3-diaminopropane, 1,4-diaminopropane, hexamethylenediamine, 2,5-dimethylhexamethylenediamine, trimethylhexamethylenediamine, diethylenetriamine, iminobispropylamine, bis(hexamethylene)triamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, N-hydroxyethylethylenediamine, and tetrakis(hydroxyethyl)ethylenediamine.

[0360] Examples of the polyetheramines include triethylene glycol diamine, tetraethylene glycol diamine, diethylene glycol bis(propylamine), polyoxypropylene diamine, and polyoxypropylene triamine.

[0361] Examples of the alicyclic amines include isophorone isodiamine, menthene diamine, N-aminoethylpiperazine, bis(4-amino-3-methyldicyclohexyl)methane, bis(aminomethyl)cyclohexane, 3,9-bis(3-aminopropyl)-2,4,8,10-tetraoxaspiro(5,5)undecane, and norbornene diamine.

[0362] Examples of the aromatic amines include tetrachloro-p-phenylenediamine, m-phenylenediamine, p-phenylenediamine, m-phenylenediamine, o-phenylenediamine, p-phenylenediamine, 2,4-diaminoanisole, 2,4-toluenediamine, 2,4-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, 4,4'-diamino-1,2-diphenylethane, 2,4-diaminodiphenylsulfone, 4,4'-diaminodiphenylsulfone, m-aminophenol, m-aminobenzylamine, benzyldimethylamine, 2-(dimethylaminomethyl)phenol, triethanolamine, methylbenzylamine, α-(m-aminophenyl)ethylamine, α-(p-aminophenyl)ethylamine, diaminodiethyldimethyldiphenylmethane, and α,α'-bis(4-aminophenyl)-p-diisopropylbenzene.

[0363] The above-mentioned amine curing agents may be used alone or in combination of two or more in any combination and blending ratio.

[0364] The amine curing agent is preferably used in an equivalent ratio of 0.1 to 2.0 of the functional groups in the curing agent relative to the epoxy groups in all epoxy resin components contained in the epoxy resin composition. More preferably, the equivalent ratio is in the range of 0.8 to 1.2. This range is preferred because it minimizes the likelihood of unreacted epoxy groups and functional groups in the curing agent remaining.

[0365] [Tertiary amine]

[0366] Examples of the tertiary amine include 1,8-diazabicyclo(5,4,0)undecene-7, triethylenediamine, benzyldimethylamine, triethanolamine, dimethylaminoethanol, and tris(dimethylaminomethyl)phenol.

[0367] The tertiary amines listed above may be used alone or in combination of two or more in any combination and blending ratio.

[0368] The tertiary amine is preferably used so that the equivalent ratio of the functional groups in the curing agent relative to the epoxy groups in all epoxy resin components contained in the epoxy resin composition is within a range of 0.1 to 2.0. More preferably, the equivalent ratio is within a range of 0.8 to 1.2. This range is preferred because it minimizes the likelihood of unreacted epoxy groups and functional groups in the curing agent remaining.

[0369] [Anhydride curing agent]

[0370] Examples of the acid anhydride-based curing agent include acid anhydrides and modified products of acid anhydrides.

[0371] Examples of the acid anhydride include phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, benzophenonetetracarboxylic anhydride, dodecenylsuccinic anhydride, polyadipic anhydride, polyazelaic anhydride, polysebacic anhydride, poly(ethyloctadecanedioic acid) anhydride, poly(phenylhexadecanedioic acid) anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, hexahydrophthalic anhydride, methylhumic anhydride, trialkyltetrahydrophthalic anhydride, methyl Cyclohexene dicarboxylic anhydride, methylcyclohexene tetracarboxylic anhydride, ethylene glycol bis(trimellitate) dianhydride, chlorobridged anhydride, nadic anhydride, methylnadic anhydride, 5-(2,5-dioxotetrahydro-3-furyl)-3-methyl-3-cyclohexane-1,2-dicarboxylic anhydride, 3,4-dicarboxy-1,2,3,4-tetrahydro-1-naphthalene succinic dianhydride, 1-methyl-dicarboxy-1,2,3,4-tetrahydro-1-naphthalene succinic dianhydride, etc.

[0372] Examples of modified acid anhydrides include those obtained by modifying the above-mentioned acid anhydrides with glycols. Examples of glycols that can be used for modification include alkylene glycols such as ethylene glycol, propylene glycol, and neopentyl glycol, and polyether glycols such as polyethylene glycol, polypropylene glycol, and polytetramethylene ether glycol. Furthermore, copolymerized polyether glycols of two or more of these glycols and / or polyether glycols can also be used.

[0373] The acid anhydride curing agents listed above may be used alone or in combination of two or more in any combination and in any blending amount.

[0374] When using an acid anhydride curing agent, it is preferably used in an equivalent ratio of 0.1 to 2.0 in terms of the functional groups in the curing agent relative to the epoxy groups in all epoxy resin components in the epoxy resin composition. More preferably, the equivalent ratio is in the range of 0.8 to 1.2. This range is preferred because it minimizes the chance of unreacted epoxy groups and functional groups in the curing agent remaining.

[0375] [Amide curing agent]

[0376] Examples of the amide-based curing agent include dicyandiamide and its derivatives, and polyamide resins.

[0377] The amide-based curing agent may be used alone or in combination of two or more in any ratio.

[0378] When an amide curing agent is used, it is preferred to use the amide curing agent in an amount of 0.1 to 20% by mass based on the total amount of the epoxy resin component and the amide curing agent in the epoxy resin composition.

[0379] [Imidazoles]

[0380] Examples of the imidazoles include 2-phenylimidazole, 2-ethyl-4(5)-methylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyano-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazole trimellitate, 1-cyanoethyl-2-phenylimidazolium trimellitate, 2,4-diamino-6-[2'-methylimidazolyl-( 1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-ethyl-4'-methylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine isocyanuric acid adduct, 2-phenylimidazole isocyanuric acid adduct, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, and adducts of epoxy resins and the above imidazoles. It should be noted that imidazoles have catalytic activity and are therefore generally classified as curing accelerators, but are classified as curing agents in the present invention.

[0381] The above-mentioned imidazoles may be used alone or in combination of two or more in any ratio.

[0382] When using imidazoles, it is preferable to use imidazoles so as to be 0.1 to 20% by mass based on the total amount of the entire epoxy resin component and imidazoles in the epoxy resin composition.

[0383] [Other curing agents]

[0384] In addition to the aforementioned curing agent, other curing agents may be used in the epoxy resin composition. There are no particular limitations on the other curing agents that can be used in the epoxy resin composition, and any known curing agent for epoxy resins may be used.

[0385] These other curing agents may be used alone or in combination of two or more.

[0386] (Other epoxy resins)

[0387] The epoxy resin composition may contain other epoxy resins other than the epoxy resin obtained by the method for producing an epoxy resin of the present invention. By containing other epoxy resins, various physical properties can be improved.

[0388] Regarding other epoxy resins that can be used in the epoxy resin composition, all epoxy resins other than the epoxy resin obtained by the method for producing an epoxy resin of the present invention are applicable. Specific examples include bisphenol A epoxy resin, bisphenol C epoxy resin, trisphenol methane epoxy resin, anthracene epoxy resin, phenol-modified xylene resin epoxy resin, bisphenol cyclododecyl epoxy resin, bisphenol diisopropylidene resorcinol epoxy resin, bisphenol F epoxy resin, bisphenol AD ​​epoxy resin, bisphenol AF epoxy resin, hydroquinone epoxy resin, methylhydroquinone epoxy resin, dibutylhydroquinone epoxy resin, resorcinol epoxy resin, methylresorcinol epoxy resin, biphenol epoxy resin, tetramethylbiphenol epoxy resin, tetramethylbisphenol F epoxy resin, dihydroxydiphenyl ether epoxy resin, epoxy resin derived from thiodiphenols, dihydroxynaphthalene epoxy resin, dihydroxyanthracene epoxy resin, dihydroxydihydroanthracene epoxy resin, dicyclopentadiene epoxy resin, epoxy resin derived from dihydroxy Epoxy resins derived from stilbenes, phenol novolac-type epoxy resins, cresol novolac-type epoxy resins, bisphenol A novolac-type epoxy resins, naphthol novolac-type epoxy resins, phenol aralkyl-type epoxy resins, naphthol aralkyl-type epoxy resins, biphenyl aralkyl-type epoxy resins, terpene phenol-type epoxy resins, dicyclopentadienephenol-type epoxy resins, epoxy resins derived from condensates of phenol and hydroxybenzaldehyde, epoxy resins derived from condensates of phenol and crotonaldehyde, epoxy resins derived from condensates of phenol and glyoxal, epoxy resins derived from co-condensation resins of heavy oil or asphalt, phenols and formaldehydes, epoxy resins derived from diaminodiphenylmethane, epoxy resins derived from aminophenol, epoxy resins derived from xylenediamine, epoxy resins derived from methylhexahydrophthalic acid, epoxy resins derived from dimer acid, etc. These may be used alone or in any combination and in any blending ratio.

[0389] When the epoxy resin composition contains the above-mentioned other epoxy resin, the content thereof is preferably 1 to 60 parts by mass, more preferably 40 parts by mass or less, based on 100 parts by mass of all epoxy resin components in the composition.

[0390] (Curing Accelerator)

[0391] The epoxy resin composition preferably contains a curing accelerator. By containing a curing accelerator, the curing time can be shortened and the curing temperature can be lowered, making it easier to obtain a desired cured product.

[0392] The curing accelerator is not particularly limited, and specific examples thereof include organic phosphines, phosphorus compounds such as phosphonium salts, tetraphenylborate salts, organic acid dihydrazides, and boron halide amine complexes.

[0393] Examples of phosphorus compounds that can be used as curing accelerators include organic phosphines such as triphenylphosphine, diphenyl(p-tolyl)phosphine, tri(alkylphenyl)phosphine, tri(alkoxyphenyl)phosphine, tri(alkyl / alkoxyphenyl)phosphine, tri(dialkylphenyl)phosphine, tri(trialkylphenyl)phosphine, tri(tetraalkylphenyl)phosphine, tri(dialkoxyphenyl)phosphine, tri(trialkoxyphenyl)phosphine, tri(tetraalkoxyphenyl)phosphine, trialkylphosphine, dialkylarylphosphine, and alkyldiarylphosphine, or complexes of these organic phosphines with organic boron, compounds obtained by adding these organic phosphines to quinone compounds such as maleic anhydride, 1,4-benzoquinone, 2,5-methylbenzoquinone, 1,4-naphthoquinone, 2,3-dimethylbenzoquinone, 2,6-dimethylbenzoquinone, 2,3-dimethoxy-5-methyl-1,4-benzoquinone, 2,3-dimethoxy-1,4-benzoquinone, and phenyl-1,4-benzoquinone, and compounds such as diazoniumphenylmethane.

[0394] Among the curing accelerators listed above, organic phosphines and phosphonium salts are preferred, and organic phosphines are most preferred. As the curing accelerator, only one of the above-mentioned substances may be used, or two or more thereof may be mixed in any combination and ratio.

[0395] The curing accelerator is preferably used in an amount of 0.1 parts by mass or more and 20 parts by mass or less relative to 100 parts by mass of the total epoxy resin components in the epoxy resin composition. When the content of the curing accelerator is above the above lower limit, a good curing acceleration effect can be obtained. On the other hand, when it is below the above upper limit, desired cured properties are easily obtained, and therefore it is preferred.

[0396] (Inorganic filler)

[0397] An inorganic filler may be blended into the epoxy resin composition. Examples of the inorganic filler include fused silica, crystalline silica, glass powder, aluminum oxide, calcium carbonate, calcium sulfate, talc, and boron nitride. One or more of these may be used alone, or two or more may be used in any combination and blending ratio. The blending amount of the inorganic filler is preferably 10 to 95% by mass of the entire epoxy resin composition.

[0398] (Release Agent)

[0399] A release agent may be blended into the epoxy resin composition. Examples of release agents include natural waxes such as carnauba wax, synthetic waxes such as polyethylene wax, higher fatty acids such as stearic acid and zinc stearate, and their metal salts, and hydrocarbon-based release agents such as paraffin wax. These may be used alone or in combination of two or more in any desired combination and blending ratio.

[0400] The amount of the release agent is preferably 0.001 to 10.0 parts by mass relative to 100 parts by mass of the total epoxy resin component in the epoxy resin composition. The amount of the release agent within the above range is preferred because it maintains curing characteristics while exhibiting good releasability.

[0401] [Coupling agent]

[0402] The epoxy resin composition may be blended with a coupling agent. The coupling agent is preferably used in combination with an inorganic filler. The addition of the coupling agent can improve the adhesion between the epoxy resin matrix and the inorganic filler. Examples of coupling agents include silane coupling agents and titanate coupling agents.

[0403] Examples of the silane coupling agent include epoxy silanes such as γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, and β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane; amino silanes such as γ-aminopropyltriethoxysilane, N-β(aminoethyl)γ-aminopropyltrimethoxysilane, N-β(aminoethyl)γ-aminopropylmethyldimethoxysilane, γ-aminopropyltrimethoxysilane, and γ-ureidopropyltriethoxysilane; mercaptosilanes such as 3-mercaptopropyltrimethoxysilane; p-phenylenyltrimethoxysilane; vinyltrichlorosilane, vinyltri(β-methoxyethoxy)silane, vinyltrimethoxysilane, vinyltriethoxysilane, and vinyl silanes; and epoxy-based, amino-based, and vinyl-based polymeric silanes.

[0404] Examples of the titanate coupling agent include isopropyl triisostearyl titanate, isopropyl tris(N-aminoethylaminoethyl) titanate, diisopropyl bis(dioctyl phosphate) titanate, tetraisopropyl bis(dioctyl phosphite) titanate, tetraoctyl bis(ditridecyl phosphite) titanate, tetrakis(2,2-diallyloxymethyl-1-butyl)bis(ditridecyl) phosphite titanate, bis(dioctyl pyrophosphate)oxyacetate titanate, and bis(dioctyl pyrophosphate)ethylene titanate.

[0405] These coupling agents may be used alone or in combination of two or more in any ratio.

[0406] When a coupling agent is used in the epoxy resin composition, the amount thereof blended is preferably 0.001 to 10.0 parts by mass relative to 100 parts by mass of the total epoxy resin component. When the amount of the coupling agent blended is at least the lower limit, the effect of improving the adhesion between the epoxy resin serving as the matrix and the inorganic filler by blending the coupling agent tends to be improved. On the other hand, when the amount of the coupling agent blended is at most the upper limit, the coupling agent is less likely to bleed out of the resulting cured product, which is preferred.

[0407] (Other compounding ingredients)

[0408] The epoxy resin composition may be mixed with components other than those mentioned above. As other mixing components, for example, flame retardants, plasticizers, reactive diluents, pigments, etc. can be mentioned, and they can be mixed appropriately as needed. However, components other than the components mentioned above can also be mixed.

[0409] Examples of the flame retardant include halogen-based flame retardants such as brominated epoxy resins and brominated phenolic resins, antimony compounds such as antimony trioxide, phosphorus-based flame retardants such as red phosphorus, phosphates, and phosphines, nitrogen-based flame retardants such as melamine derivatives, and inorganic flame retardants such as aluminum hydroxide and magnesium hydroxide.

[0410] (Curing method)

[0411] By curing the epoxy resin composition, a cured epoxy resin product can be obtained. There is no particular limitation on the curing method, and the cured product can generally be obtained by a thermal curing reaction based on heating. In the thermal curing reaction, it is preferred to appropriately select the curing temperature according to the type of curing agent used. For example, when a phenolic curing agent is used, the curing temperature is generally 80 to 250°C. In addition, by adding a curing accelerator to these curing agents, the curing temperature can also be lowered. The reaction time is preferably 0.01 to 20 hours. When the reaction time is above the lower limit, the curing reaction tends to proceed more easily and fully, so it is preferred. On the other hand, when the reaction time is below the upper limit, it is easy to reduce the deterioration caused by heating and the energy loss during heating, so it is preferred.

[0412] (use)

[0413] The epoxy resin cured product obtained by curing the epoxy resin composition has a low linear expansion coefficient and can be a cured product excellent in heat crack resistance.

[0414] Therefore, cured epoxy resins can be effectively used in any application requiring these properties. For example, they can be used in coatings such as automotive electrodeposition coatings, heavy-duty corrosion protection coatings for ships and bridges, and coatings for the interior surface coating of beverage cans; in the electrical and electronic fields such as laminates, semiconductor sealing materials, insulating powder coatings, and coil impregnation; and in the civil engineering, construction, and adhesive fields such as bridge earthquake reinforcement, concrete reinforcement, building flooring, water supply facility linings, drainage and permeable pavement, and adhesives for vehicles and aircraft.

[0415] The epoxy resin composition may be used after being cured for the above-mentioned applications, or may be cured during the production process for the above-mentioned applications.

[0416] Example

[0417] Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. However, the present invention is not limited to the following Examples unless the gist of the present invention is exceeded.

[0418] [Raw materials and reagents]

[0419] As the polycarbonate resin, "NOVAREX (registered trademark) M7027BF" manufactured by Mitsubishi Chemical Engineering-Plastics Corporation was used.

[0420] Phenol, o-cresol, m-cresol, a cresol isomer mixture (o-cresol, m-cresol, p-cresol), toluene, sodium hydroxide, potassium hydroxide, methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, tripropylamine, p-toluenesulfonic acid, methanesulfonic acid, 35% hydrochloric acid, 98% sulfuric acid, 85% phosphoric acid, acetic acid, acetonitrile, cesium carbonate, pyridine, sodium chloride, dibromophenol, and carbon tetrachloride were reagents from Fujifilm Wako Pure Chemical Industries, Ltd.

[0421] Diphenyl carbonate produced by Mitsubishi Chemical Corporation was used.

[0422] [analyze]

[0423] The formation and purity of bisphenol were confirmed by high performance liquid chromatography using the following procedures and conditions.

[0424] · Apparatus: LC-2010A manufactured by Shimadzu Corporation, 5μm 150mm×4.6mm ID manufactured by Waters

[0425] Method: Low-pressure gradient method

[0426] Analysis temperature: 40°C

[0427] Eluent composition:

[0428] Liquid A: Acetonitrile

[0429] Solution B: 85% phosphoric acid: water = 1 mL: 999 mL solution

[0430] At analysis time 0 minutes, the eluent composition was solution A:solution B = 35:65 (volume ratio, the same applies hereinafter). From analysis time 0 to 5 minutes, the eluent composition was maintained at solution A:solution B = 35:65, and then gradually changed to solution A:solution B = 90:10 from analysis time 5 to 40 minutes.

[0431] Flow rate: 0.85 mL / min

[0432] Detection wavelength: 280nm

[0433] Analysis of pyridine and phenol contained in the neutralized wastewater was performed by gas chromatography using the following procedures and conditions.

[0434] Device: GC-2014 manufactured by Shimadzu Corporation

[0435] Agilent DB-10.530mm×30m 1.5μm

[0436] Detection method: FID

[0437] Vaporization chamber temperature: 230℃

[0438] Detector temperature: 300°C

[0439] The column temperature was maintained at 50°C from 0 to 5 minutes of analysis time, gradually increased to 280°C from 5 to 30 minutes of analysis time, and maintained at 280°C from 30 to 40 minutes of analysis time.

[0440] Quantitative method: internal standard method using biphenyl as internal standard

[0441] The amount of sodium chloride contained in the neutralized wastewater was calculated from the mass of the remaining components by evaporating the neutralized wastewater to dryness.

[0442] Analysis of dibromophenol contained in the hydrochloric acid wastewater was performed by gas chromatography using the following procedures and conditions.

[0443] Device: GC-2014 manufactured by Shimadzu Corporation

[0444] Agilent DB-10.530mm×30m 1.5μm

[0445] Detection method: FID

[0446] Vaporization chamber temperature: 230℃

[0447] Detector temperature: 300°C

[0448] During the analysis time of 0 to 5 minutes, the column temperature was maintained at 50°C. During the analysis time of 5 to 30 minutes, the column temperature was gradually increased to 280°C. During the analysis time of 30 to 40 minutes, the column temperature was maintained at 280°C.

[0449] Quantification was performed using the absolute standard curve method.

[0450] The concentration of hydrogen chloride contained in the hydrochloric acid wastewater was measured by neutralization titration using the following apparatus.

[0451] Device: Kyoto Electronics Co., Ltd. potentiometric automatic titrator AT-610

[0452] Analysis of carbon tetrachloride contained in the sodium hydroxide wastewater was performed by gas chromatography using the following procedures and conditions.

[0453] Device: Agilent Technologies, Inc.

[0454] J&WDB-17 0.32mm×30m×0.5μm

[0455] At analysis time 0 minutes, the column temperature was set to 50°C, and the temperature was increased at 10°C per minute to 250°C.

[0456] Detector: MS

[0457] The concentration of sodium hydroxide contained in the sodium hydroxide wastewater was measured using the following apparatus.

[0458] Device: Kyoto Electronics Industry Co., Ltd. potentiometric automatic titrator AT-610

[0459] The concentration of sodium chloride contained in the sodium hydroxide wastewater was calculated by measuring the chloride ion concentration using the following apparatus and determining the amount of sodium equivalent to the molar amount of the obtained chloride ions.

[0460] Device: Kyoto Electronics Industry Co., Ltd. potentiometric automatic titrator AT-610

[0461] [Viscosity average molecular weight (Mv)]

[0462] The viscosity average molecular weight (Mv) was calculated by dissolving a polycarbonate resin in dichloromethane (concentration 6.0 g / L) and measuring the specific viscosity (ηsp) at 20° C. using an Ubbelohde viscometer.

[0463] ηsp / C=[η](1+0.28ηsp)

[0464] [η] = 1.23 × 10 -4 Mv 0.83

[0465] [Melted color of bisphenol]

[0466] Regarding the melt color of bisphenol, 20 g of bisphenol was placed in a test tube "P-24" (2 mmφ×200 mm) manufactured by Nippon Denshoku Glass Co., Ltd., melted at 174°C for 30 minutes, and its Hazen color number was measured using "OME7700" manufactured by Nippon Denshoku Industries Co., Ltd.

[0467] [pH measurement]

[0468] The pH was measured using a pH meter "pH METER ES-73" manufactured by HORIBA, Ltd., on a 25° C. aqueous phase taken out from the flask.

[0469] (Example 1)

[0470] [Example 1-1]

[0471] In a jacketed separable flask equipped with a Dimrod condenser, a stirring blade, and a thermometer, 80 g of polycarbonate resin (the repeating unit of the polycarbonate resin is 254 g / mol, so the repeating unit conversion is 80 g ÷ 254 g / mol = 0.315 mol), 30 g of water, 250 g of phenol, and 320 g of a 25% by mass sodium hydroxide aqueous solution were placed under a nitrogen atmosphere at room temperature. The reaction solution was in the form of a slurry.

[0472] Thereafter, the internal temperature was raised to 80° C., and the reaction was carried out for 5 hours while maintaining the temperature at 80° C., thereby obtaining a uniform solution.

[0473] After 200 g of toluene was added to the obtained uniform solution, 35% by mass hydrochloric acid was added until the pH of the aqueous phase became 8.6, whereby carbon dioxide gas was generated.

[0474] Thereafter, stirring was stopped, oil-water separation was performed, and the aqueous phase was taken out from the flask to obtain an organic phase 1. The composition of a portion of the obtained organic phase 1 was confirmed by high performance liquid chromatography, and the formation of bisphenol A was confirmed.

[0475] The obtained organic phase 1 was transferred to a distillation apparatus equipped with a thermometer, a stirring blade, a distillation tube, and a pressure regulator. While observing the distillate amount, the internal temperature was slowly raised to 180°C and the internal pressure was slowly reduced from normal pressure to 100 hPa to distill off water, toluene, and phenol.

[0476] Thereafter, the pressure in the flask was restored with nitrogen, the internal temperature was lowered to 80° C., and 200 g of toluene was added to obtain an organic phase 2. The obtained organic phase 2 was washed five times with 50 g of deionized water to obtain an organic phase 3.

[0477] The obtained organic phase 3 was cooled to 20° C. to obtain a slurry, which was then filtered to obtain a filter cake.

[0478] The obtained filter cake was dried using a rotary evaporator to obtain 35 g of bisphenol A. The obtained bisphenol A had a purity of 99.8% by mass and a melt color of APHA 165.

[0479] [Examples 1-2]

[0480] Example 1-1 was carried out in the same manner as Example 1-1 except that 320 g of a 25 mass % aqueous potassium hydroxide solution was used instead of 320 g of a 25 mass % aqueous sodium hydroxide solution. 41 g of bisphenol A was obtained with a purity of 99.8 mass % and a melt color of APHA 157.

[0481] (Example 2)

[0482] In a jacketed separable flask equipped with a Dimrod condenser, a stirring blade, and a thermometer, 80 g of polycarbonate resin (0.315 mol in terms of repeating units), 30 g of water, 250 g of phenol, and 10 g of sodium carbonate were placed at room temperature under a nitrogen atmosphere. The reaction solution was in the form of a slurry.

[0483] Thereafter, the internal temperature was raised to 85° C., and the reaction was carried out for 5 hours while maintaining the temperature at 85° C., thereby obtaining a uniform solution.

[0484] The composition of a portion of the resulting homogeneous solution was confirmed by high-performance liquid chromatography (HPLC), revealing a production of 19.2% by mass of bisphenol A. The mass of the homogeneous solution was 80 g + 30 g + 250 g + 10 g = 370 g, and the amount of bisphenol produced was 19.2% by mass × 370 g ÷ 228 g / mol = 0.312 mol, resulting in a reaction rate of 0.312 mol ÷ 0.315 mol × 100 = 99%.

[0485] (Example 3)

[0486] [Example 3-1]

[0487] In a jacketed separable flask equipped with a Dimrod condenser, a stirring blade, and a thermometer, 80 g of polycarbonate resin (0.315 mol in terms of repeating units), 30 g of water, 240 g of phenol, and 2 g of a 40% by mass aqueous solution of methylamine were placed under a nitrogen atmosphere at room temperature. The reaction mixture was in the form of a slurry.

[0488] Thereafter, the internal temperature was raised to 80° C. and the reaction was carried out for 5 hours while maintaining the temperature at 80° C., thereby obtaining a uniform solution. During the reaction, generation of carbon dioxide was observed.

[0489] A portion of the obtained uniform solution was taken out, and the composition was confirmed by high performance liquid chromatography. As a result, the generated amount of bisphenol A was 19.9% ​​by mass.

[0490] The mass of the uniform solution is 80 g + 30 g + 240 g + 2 g = 352 g, the amount of bisphenol produced is 19.9 mass% × 352 g ÷ 228.29 g / mole = 0.307 mol, and the reaction rate is 0.307 mol ÷ 0.315 mol × 100 = 97%.

[0491] [Example 3-2]

[0492] In Example 3-1, the same procedure as in Example 3-1 was carried out except that 2 g of a 50 mass % dimethylamine aqueous solution was added instead of 2 g of a 40 mass % methylamine aqueous solution.

[0493] A portion of the obtained uniform solution was taken out, and the composition was confirmed by high performance liquid chromatography. As a result, the generated amount of bisphenol A was 19.6% by mass.

[0494] The mass of the uniform solution is 80 g + 30 g + 240 g + 2 g = 352 g, the amount of bisphenol produced is 19.6 mass% × 352 g ÷ 228.29 g / mole = 0.302 mol, and the reaction rate is 0.302 mol ÷ 0.315 mol × 100 = 96%.

[0495] [Example 3-3]

[0496] In Example 3-1, the same procedures as in Example 3-1 were carried out except that 5 g of the trimethylamine aqueous solution was added instead of 2 g of the 40% by mass methylamine aqueous solution.

[0497] A portion of the obtained uniform solution was taken out, and the composition was confirmed by high performance liquid chromatography. As a result, the generated amount of bisphenol A was 19.6% by mass.

[0498] The mass of the uniform solution is 80 g + 30 g + 240 g + 5 g = 355 g, the amount of bisphenol produced is 19.6 mass% × 355 g ÷ 228.29 g / mole = 0.304 mol, and the reaction rate is 0.304 mol ÷ 0.315 mol × 100 = 97%.

[0499] [Examples 3-4]

[0500] In Example 3-1, the same procedures as in Example 3-1 were carried out except that 5 g of a 70 mass % ethylamine aqueous solution was added instead of 2 g of a 40 mass % methylamine aqueous solution.

[0501] A portion of the obtained uniform solution was taken out, and the composition was confirmed by high performance liquid chromatography. As a result, the generated amount of bisphenol A was 20.1% by mass.

[0502] The mass of the uniform solution is 80 g + 30 g + 240 g + 5 g = 355 g, the amount of bisphenol produced is 20.1 mass% × 355 g ÷ 228.29 g / mole = 0.313 mol, and the reaction rate is 0.313 mol ÷ 0.315 mol × 100 = 99%.

[0503] [Examples 3-5]

[0504] In Example 3-1, the same procedures as in Example 3-1 were carried out except that 10 g of diethylamine was added instead of 2 g of the 40% by mass aqueous methylamine solution.

[0505] A portion of the obtained uniform solution was taken out, and the composition was confirmed by high performance liquid chromatography. As a result, the generated amount of bisphenol A was 19.7% by mass.

[0506] The mass of the uniform solution is 80 g + 30 g + 240 g + 10 g = 360 g, the amount of bisphenol produced is 19.7 mass% × 360 g ÷ 228.29 g / mole = 0.311 mol, and the reaction rate is 0.311 mol ÷ 0.315 mol × 100 = 99%.

[0507] [Examples 3-6]

[0508] In Example 3-1, the same procedures as in Example 3-1 were carried out except that 10 g of triethylamine was added instead of 2 g of the 40% by mass aqueous methylamine solution.

[0509] A portion of the resulting homogeneous solution was removed and its composition confirmed by high-performance liquid chromatography (HPLC). The result showed 19.6% by mass of bisphenol A. The mass of the homogeneous solution was 80 g + 30 g + 240 g + 10 g = 360 g. The amount of bisphenol A produced was 19.6% by mass × 360 g ÷ 228.29 g / mol = 0.309 mol, and the reaction rate was 0.309 mol ÷ 0.315 mol × 100 = 98%.

[0510] [Examples 3-7]

[0511] In Example 3-1, the same procedures as in Example 3-1 were carried out except that 10 g of tripropylamine was added instead of 2 g of the 40% by mass aqueous methylamine solution.

[0512] A portion of the resulting homogeneous solution was removed and its composition confirmed by high-performance liquid chromatography (HPLC). The result showed that 19.4% by mass of bisphenol A was generated. The mass of the homogeneous solution was 80 g + 30 g + 240 g + 10 g = 360 g. The amount of bisphenol generated was 19.4% by mass × 360 g ÷ 228.29 g / mol = 0.306 mol, and the reaction rate was 0.306 mol ÷ 0.315 mol × 100 = 97%.

[0513] Table 1 shows the results of Examples 3-1 to 3-7.

[0514] [Table 1]

[0515]

[0516] [Examples 3-8]

[0517] In Example 3-6, the same procedures as in Example 3-6 were followed except that the internal temperature was raised to 70°C and maintained at 70°C for 5 hours instead of being raised to 80°C and maintained at 80°C for 5 hours.

[0518] A portion of the resulting solution was removed and its composition confirmed by high-performance liquid chromatography (HPLC). The result showed 6.5% by mass of bisphenol A. The mass of the solution was 80 g + 30 g + 240 g + 10 g = 360 g. The amount of bisphenol A produced was 6.5% by mass × 360 g ÷ 228.29 g / mol = 0.103 mol, and the reaction rate was 0.103 mol ÷ 0.315 mol × 100 = 33%.

[0519] [Example 3-8-2]

[0520] In Example 3-8, the same procedure as in Example 3-8 was carried out except that the reaction was carried out for 13 hours while maintaining the temperature at 70° C. instead of for 5 hours.

[0521] A portion of the resulting solution was removed and its composition confirmed by high-performance liquid chromatography (HPLC). The result showed 13.1% by mass of bisphenol A. The mass of the solution was 80 g + 30 g + 240 g + 10 g = 360 g. The amount of bisphenol A produced was 13.1% by mass × 360 g ÷ 228.29 g / mol = 0.207 mol, and the reaction rate was 0.207 mol ÷ 0.315 mol × 100 = 66%.

[0522] Table 2 shows the results of Examples 3-8 to 3-8-2.

[0523] [Table 2]

[0524] Examples 3-8 Example 3-8-2 catalyst Triethylamine Triethylamine organic solvents phenol phenol water have have Reaction temperature 70℃ 70℃ Reaction time 5 hours 13 hours Response rate 33％ 66％

[0525] [Examples 3-9]

[0526] In Example 3-6, the same procedures as in Example 3-6 were followed except that the internal temperature was raised to 60°C and maintained at 60°C for 5 hours instead of being raised to 80°C and maintained at 80°C for 5 hours.

[0527] A portion of the resulting solution was removed and its composition confirmed by high-performance liquid chromatography (HPLC). The result showed 1.8% by mass of bisphenol A produced. The mass of the solution was 80 g + 30 g + 240 g + 10 g = 360 g. The amount of bisphenol produced was 1.8% by mass × 360 g ÷ 228.29 g / mol = 0.028 mol, and the reaction rate was 0.028 mol ÷ 0.315 mol × 100 = 9%.

[0528] [Example 3-9-2]

[0529] In Example 3-9, the same procedures as in Example 3-9 were carried out except that the reaction was carried out for 56 hours while maintaining the temperature at 60° C. instead of for 5 hours.

[0530] A portion of the resulting solution was removed and its composition confirmed by high-performance liquid chromatography (HPLC). The result showed 12.9% by mass of bisphenol A. The mass of the solution was 80 g + 30 g + 240 g + 10 g = 360 g. The amount of bisphenol A produced was 12.9% by mass × 360 g ÷ 228.29 g / mol = 0.203 mol, and the reaction rate was 0.203 mol ÷ 0.315 mol × 100 = 64%.

[0531] Table 3 shows the results of Examples 3-9 to 3-9-2.

[0532] [Table 3]

[0533] Examples 3-9 Example 3-9-2 catalyst Triethylamine Triethylamine organic solvents phenol phenol water have have Reaction temperature 60℃ 60℃ Reaction time 5 hours 56 hours Response rate 9％ 64％

[0534] [Comparative Example 3-1]

[0535] In a jacketed separable flask equipped with a Dimrod condenser, a stirring blade, and a thermometer, 80 g of a polycarbonate resin (0.315 mol in terms of repeating units), 30 g of water, 240 g of dichloromethane, and 2 g of a 40% by mass aqueous methylamine solution were placed under a nitrogen atmosphere at room temperature.

[0536] Thereafter, since the boiling point of dichloromethane is 40°C, the internal temperature was raised to 40°C, and the reaction was carried out for 5 hours while maintaining the temperature at 40°C.

[0537] A portion of the obtained homogeneous solution was taken out and its composition was confirmed by high performance liquid chromatography. As a result, only a trace amount of bisphenol A was found.

[0538] [Comparative Example 3-2]

[0539] In Example 3-6, the same procedures as in Example 3-6 were carried out except that 30 g of water was not used. It should be noted that generation of carbon dioxide was not confirmed during the reaction.

[0540] A portion of the obtained uniform solution was taken out, and the composition was confirmed by high performance liquid chromatography. As a result, the generated amount of bisphenol A was 13.1% by mass.

[0541] The mass of the uniform solution is 80 g + 240 g + 10 g = 330 g, the amount of bisphenol produced is 13.1 mass% × 322 g ÷ 228 g / mole = 0.190 mol, and the reaction rate is 0.190 mol ÷ 0.315 mol × 100 = 60%.

[0542] Furthermore, it was found that the amount of bisphenol A produced remained unchanged at the same level even when the reaction time was further prolonged.

[0543] [Comparative Example 3-3]

[0544] Comparative Example 3-2 was carried out in the same manner as in Comparative Example 3-2, except that the reaction temperature was changed to 60° C. instead of 80° C. During the reaction, no generation of carbon dioxide was observed.

[0545] A portion of the obtained uniform solution was taken out and its composition was confirmed by high performance liquid chromatography. As a result, the amount of bisphenol A produced was a trace amount.

[0546] Furthermore, even when the reaction time was further prolonged, the amount of bisphenol A produced did not change.

[0547] [Comparative Examples 3-4]

[0548] In Example 3-6, the same procedures as in Example 3-6 were carried out except that 240 g of phenol was not used.

[0549] Most of the supplied polycarbonate resin remained as a solid component in the obtained reaction solution. A portion of the obtained reaction solution was taken out and its composition was confirmed by high performance liquid chromatography, which revealed that a trace amount of bisphenol A was produced.

[0550] Table 4 shows the results of Comparative Examples 3-1 to 3-4.

[0551] [Table 4]

[0552] Comparative Example 3-1 Comparative Example 3-2 Comparative Example 3-3 Comparative Examples 3-4 catalyst Methylamine Triethylamine Triethylamine Triethylamine organic solvents dichloromethane phenol phenol none water have none none have Reaction temperature 40℃ 80℃ 60℃ 80℃ Response rate trace amount 60％ trace amount trace amount

[0553] Tables 1 to 4 show that the combined use of phenol and water allows efficient decomposition of polycarbonate resin. Furthermore, since no chlorinated hydrocarbon solvents such as dichloromethane are used, this decomposition method has a low environmental burden. Furthermore, in Examples 3-1 to 3-9-2, the polycarbonate resin decomposes into bisphenol A and carbon dioxide, making recovery and purification of bisphenol A easy.

[0554] [Examples 3-10]

[0555] The reaction solution obtained in Example 3-6 was transferred to a distillation apparatus equipped with a thermometer, a stirring blade, a distillation tube, and a pressure regulator. While observing the distillate amount, the internal temperature was slowly raised to 180°C and the internal pressure was slowly reduced from normal pressure to 100 hPa to distill off water, triethylamine, and phenol.

[0556] Thereafter, the pressure in the flask was restored with nitrogen, the internal temperature was lowered to 80° C., and 200 g of toluene was added to obtain an organic phase 1.

[0557] The obtained organic phase 1 was washed five times with 50 g of desalted water to obtain an organic phase 2. The obtained organic phase 2 was cooled to 20° C. to obtain a slurry. The obtained slurry was filtered to obtain a filter cake.

[0558] The obtained filter cake was dried using a rotary evaporator to obtain 32 g of bisphenol A. The obtained bisphenol A had a purity of 99.8% by mass and a melt color of APHA 155.

[0559] (Example 4)

[0560] [Example 4-1]

[0561] In a jacketed separable flask equipped with a Dimer condenser, a stirring blade, and a thermometer, 240 g of o-cresol and 30 g of water were added under a nitrogen atmosphere, followed by 15 g of triethylamine and stirring. Subsequently, 80 g of polycarbonate resin (0.315 mol in terms of repeating units) was added.

[0562] Thereafter, the internal temperature was raised to 80° C., and the reaction was carried out for 5 hours while maintaining the temperature at 80° C., thereby obtaining a uniform solution.

[0563] A portion of the resulting homogeneous solution was removed and its composition confirmed by high-performance liquid chromatography (HPLC). The result showed 19.4% by mass of bisphenol A. The mass of the homogeneous solution was 240 g + 30 g + 15 g + 80 g = 365 g. The amount of bisphenol A produced was 19.4% by mass × 365 g ÷ 228.29 g / mol = 0.310 mol, and the reaction rate was 0.310 mol ÷ 0.315 mol × 100 = 98%.

[0564] The obtained reaction solution was cooled to 20°C and allowed to stand for 12 hours to obtain a slurry. The obtained slurry was filtered under reduced pressure to obtain a filter cake 1.

[0565] The obtained filter cake 1 was suspended and washed with toluene to obtain 21 g of filter cake 2.

[0566] High-performance liquid chromatography (HPLC) analysis of a portion of filter cake 2 revealed 0.5 mass% o-cresol and 78.2 mass% bisphenol A. Filter cake 2 contained 21 g of o-cresol × 0.5 mass% ÷ 108 g / mol = 1 mmol, and 21 g of bisphenol A × 78.2 mass% ÷ 228 g / mol = 72 mmol, indicating that the filter cake contained bisphenol A.

[0567] [Example 4-2]

[0568] The same procedure as in Example 4-1 was repeated except that m-cresol was used instead of o-cresol to obtain 20 g of filter cake 2.

[0569] High-performance liquid chromatography (HPLC) analysis of a portion of filter cake 2 revealed 0.6% by mass of m-cresol and 78.5% by mass of bisphenol A. Filter cake 2 contained 20 g of m-cresol × 0.6% by mass ÷ 108 g / mol = 1 mmol, and 20 g of bisphenol A × 78.5% by mass ÷ 228 g / mol = 69 mmol, indicating that the filter cake contained bisphenol A.

[0570] [Example 4-3]

[0571] The same procedure as in Example 4-1 was carried out except that a cresol isomer mixture was used instead of o-cresol to obtain 22 g of a filter cake 2.

[0572] High-performance liquid chromatography (HPLC) analysis of a portion of filter cake 2 revealed 0.3 mass% of the cresol isomer mixture component and 79.7 mass% of bisphenol A. Filter cake 2 contained 22 g of the cresol isomer mixture × 0.3 mass% ÷ 108 g / mol = 1 mmol, and 22 g of bisphenol A × 79.7 mass% ÷ 228 g / mol = 77 mmol, indicating that the filter cake contained bisphenol A.

[0573] [Example 4-4]

[0574] The filter cake obtained in Example 4-1 was placed in a separable flask equipped with a thermometer, a stirring blade, and a condenser. 50 g of toluene and 50 g of deionized water were then added, and the temperature was raised to 80°C to obtain organic phase 1. Organic phase 1 was washed five times with 50 g of deionized water to obtain organic phase 2.

[0575] The obtained organic phase 2 was cooled to 20° C. to obtain a slurry, which was then filtered to obtain a filter cake.

[0576] The obtained filter cake was dried using a rotary evaporator to obtain 11 g of bisphenol A. The obtained bisphenol A had a purity of 99.8% by mass and a melt color of APHA 95.

[0577] (Example 5)

[0578] The same procedure as in Example 4-1 was repeated except that phenol was used instead of o-cresol to obtain 25 g of a filter cake 2.

[0579] High-performance liquid chromatography (HPLC) analysis of a portion of filter cake 2 revealed 23% by mass of phenol and 57% by mass of bisphenol A. Filter cake 2 contained 61 mmoles of phenol (25 g x 23% by mass) and 63 mmoles of bisphenol A (25 g x 57% by mass) of bisphenol A (228 g / mol). This indicated that the filter cake was a eutectic of phenol and bisphenol A.

[0580] Table 5 also shows the organic solvents and filter cakes in Examples 4-1 to 4-3 and Example 5.

[0581] The results of Examples 4-1 to 4-3 show that by using cresol, a filter cake of bisphenol A can be obtained even without distilling off phenol.

[0582] Furthermore, the results of Example 5 show that a eutectic of bisphenol A and phenol can be obtained by crystallization in the co-presence of phenol.

[0583] [Table 5]

[0584]

[0585] (Example 6)

[0586] [Example 6-1]

[0587] In a jacketed separable flask equipped with a Dimrod condenser, a stirring blade, and a thermometer, 80 g of a polycarbonate resin (0.315 mol in terms of repeating units), 100 g of water, 240 g of phenol, and 80 g of p-toluenesulfonic acid were placed at room temperature under a nitrogen atmosphere.

[0588] Thereafter, the internal temperature was raised to 80° C., and the reaction was carried out for 1 hour while maintaining the temperature at 80° C. to obtain a reaction liquid. During the reaction, generation of carbon dioxide was observed.

[0589] A portion of the resulting reaction solution was removed and its composition was confirmed by high-performance liquid chromatography (HPLC). The result showed that 13.2% by mass of bisphenol A was generated. The mass of the reaction solution was 80 g + 100 g + 240 g + 80 g = 500 g. The bisphenol A generated was 13.2% by mass × 500 g ÷ 228.29 g / mol = 0.289 mol, and the reaction rate was 0.289 mol ÷ 0.315 mol × 100 = 92%.

[0590] [Example 6-2]

[0591] In Example 6-1, the same procedures as in Example 6-1 were carried out except that 40 g of methanesulfonic acid was added instead of 80 g of p-toluenesulfonic acid.

[0592] A portion of the resulting reaction solution was removed and its composition was confirmed by high-performance liquid chromatography (HPLC). The result showed that 14.3% by mass of bisphenol A was generated. The mass of the reaction solution was 80 g + 100 g + 240 g + 40 g = 460 g. The bisphenol A generated was 14.3% by mass × 460 g ÷ 228.29 g / mol = 0.288 mol, and the reaction rate was 0.288 mol ÷ 0.315 mol × 100 = 91%.

[0593] [Example 6-3]

[0594] In Example 6-1, the same procedures as in Example 6-1 were carried out except that 240 g of 35% hydrochloric acid was added instead of 80 g of p-toluenesulfonic acid.

[0595] A portion of the resulting reaction solution was removed and its composition was confirmed by high-performance liquid chromatography (HPLC). The result showed that 8.5% by mass of bisphenol A was generated. The mass of the reaction solution was 80 g + 100 g + 240 g + 240 g = 660 g. The bisphenol A generated was 8.5% by mass × 660 g ÷ 228.29 g / mol = 0.246 mol, and the reaction rate was 0.246 mol ÷ 0.315 mol × 100 = 78%.

[0596] [Example 6-4]

[0597] The same procedures as in Example 6-1 were carried out except that 100 g of 98% sulfuric acid was added instead of 80 g of p-toluenesulfonic acid.

[0598] A portion of the resulting reaction solution was removed and its composition was confirmed by high-performance liquid chromatography (HPLC). The result showed that 11.8% by mass of bisphenol A was generated. The mass of the reaction solution was 80 g + 100 g + 240 g + 100 g = 520 g. The bisphenol A generated was 11.8% by mass × 520 g ÷ 228.29 g / mol = 0.269 mol, and the reaction rate was 0.269 mol ÷ 0.315 mol × 100 = 85%.

[0599] [Example 6-5]

[0600] In Example 6-1, the same procedures as in Example 6-1 were carried out except that 200 g of 85% phosphoric acid was added instead of 80 g of p-toluenesulfonic acid.

[0601] A portion of the resulting reaction solution was removed and its composition was confirmed by high-performance liquid chromatography (HPLC). The result showed that 9.6% by mass of bisphenol A was generated. The mass of the reaction solution was 80 g + 100 g + 240 g + 200 g = 620 g. The amount of bisphenol A generated was 9.6% by mass × 620 g ÷ 228.29 g / mol = 0.261 mol, and the reaction rate was 0.261 mol ÷ 0.315 mol × 100 = 83%.

[0602] The acids and reaction rates of Examples 6-1 to 6-5 are also shown in Table 6. The results show that the polycarbonate resin can be decomposed by using an acid.

[0603] [Table 6]

[0604] Example 6-1 Example 6-2 Example 6-3 Example 6-4 Example 6-5 acid p-Toluenesulfonic acid Methanesulfonic acid 35% hydrochloric acid 98% sulfuric acid 85% phosphoric acid Response rate 92％ 91％ 78％ 85％ 83％

[0605] [Example 6-6]

[0606] 200 g of toluene was added to the reaction solution obtained in Example 6-1, and then a 25% aqueous sodium hydroxide solution was added to adjust the pH to 9.1. The aqueous phase was removed to obtain an organic phase 1.

[0607] The resulting organic phase 1 was transferred to a distillation apparatus equipped with a thermometer, stirring blade, distillation tube, and pressure regulator. While monitoring the distillate output, the internal temperature was slowly raised to 180°C and the internal pressure was slowly reduced from atmospheric pressure to 100 hPa to distill off water and phenol. The pressure in the flask was then restored with nitrogen, the internal temperature was lowered to 80°C, and 200 g of toluene was added to obtain organic phase 2. The resulting organic phase 2 was washed five times with 50 g of deionized water to obtain organic phase 3.

[0608] The resulting organic phase 3 was cooled to 20°C to obtain a slurry. The resulting slurry was filtered to obtain a filter cake. The filter cake was dried using a rotary evaporator to obtain 25 g of bisphenol A. The resulting bisphenol A had a purity of 99.8% by mass and a melt color of APHA 162.

[0609] (Example 7)

[0610] [Example 7-1]

[0611] In a 45 mL glass reaction vessel equipped with a stirrer and a distillation tube, 10.00 g (0.04 mol) of bisphenol A obtained in Example 1-1, 9.95 g (0.05 mol) of diphenyl carbonate, and 18 μL of a 400 ppm by mass cesium carbonate aqueous solution were placed. The glass reaction vessel was depressurized to approximately 100 Pa and then returned to atmospheric pressure with nitrogen three times, replacing the interior of the vessel with nitrogen. The vessel was then immersed in an oil bath at 220°C to dissolve the contents.

[0612] The stirrer speed was set to 100 revolutions per minute, while distilling away phenol, a by-product of the oligomerization reaction between bisphenol A and diphenyl carbonate, from the reaction tank. The pressure in the reaction tank was reduced from 101.3 kPa to 13.3 kPa absolute over 40 minutes. The transesterification reaction was then conducted for 80 minutes while further distilling away phenol, while maintaining the pressure at 13.3 kPa. The external temperature of the reaction tank was then raised to 290°C, while the pressure in the reaction tank was simultaneously reduced from 13.3 kPa absolute to 399 Pa absolute over 40 minutes, removing the distilled phenol from the system. The absolute pressure in the reaction tank was then reduced to 30 Pa absolute, and the polycondensation reaction was continued. The polycondensation reaction was terminated when the stirrer in the reaction tank reached a predetermined stirring power. The duration from the temperature increase to 290°C to the completion of the polymerization was 120 minutes.

[0613] Next, the absolute pressure in the reaction tank was returned to 101.3 kPa with nitrogen gas, and then the pressure was increased to 0.2 MPa in gauge pressure, and the polycarbonate resin was taken out from the reaction tank to obtain a regenerated polycarbonate resin.

[0614] The viscosity average molecular weight (Mv) of the obtained recycled polycarbonate resin was 27,100.

[0615] [Example 7-2]

[0616] In Example 7-1, the same procedures as in Example 7-1 were carried out except that the bisphenol A obtained in Example 3-10 was used instead of the bisphenol A obtained in Example 1-1.

[0617] The viscosity average molecular weight (Mv) of the obtained recycled polycarbonate resin was 26,800.

[0618] [Example 7-3]

[0619] In Example 7-1, the same procedures as in Example 7-1 were carried out except that the bisphenol A obtained in Example 4-4 was used instead of the bisphenol A obtained in Example 1-1.

[0620] The viscosity average molecular weight (Mv) of the obtained recycled polycarbonate resin was 24,000.

[0621] [Example 7-4]

[0622] In Example 7-1, the same procedures as in Example 7-1 were carried out except that the bisphenol A obtained in Example 6-6 was used instead of the bisphenol A obtained in Example 1-1.

[0623] The viscosity average molecular weight (Mv) of the obtained recycled polycarbonate resin was 26,000.

[0624] (Example 8)

[0625] [Example 8-1]

[0626] 8-1-1: Acquisition of neutralized wastewater

[0627] Diphenyl carbonate was produced according to the "Production of Diphenyl Carbonate" (paragraphs 0050-0051) of Example 12 of Japanese Patent Application Laid-Open No. 2004-345883. The aqueous phase generated during separation in the neutralization mixing tank was collected as neutralization wastewater. The resulting neutralization wastewater had a composition of 0.3% by mass of pyridine, 1.4% by mass of phenol, and 4% by mass of sodium chloride.

[0628] 8-1-2: Production of bisphenol (decomposition of polycarbonate resin)

[0629] In a jacketed detachable flask equipped with a Dimrod condenser, a stirring blade, and a thermometer, polycarbonate resin (80 g, 0.315 mol in terms of repeating units), pyridine (2 g), the neutralized wastewater obtained in 8-1-1 (29 g), and phenol (240 g) were placed under a nitrogen atmosphere at room temperature. The reaction solution was in the form of a slurry. The mass of the reaction solution was 80 g + 2 g + 29 g + 240 g = 351 g. Thereafter, the temperature was raised to 85° C., and the reaction was carried out for 4 hours while maintaining the temperature at 85° C.

[0630] The composition of a portion of the obtained reaction solution was confirmed by high performance liquid chromatography, and the result showed that bisphenol A was 15.5 mass % (15.5÷100×351 g=54.4 g, decomposition rate of polycarbonate resin 54.4 g÷228 g / mol÷0.315 mol×100=75.7 mol %).

[0631] The obtained reaction solution was transferred to a distillation apparatus equipped with a thermometer, a stirring blade, a distillation tube, and a pressure regulator. While observing the distillate amount, the internal temperature was slowly raised to 180°C and the internal pressure was slowly reduced from normal pressure to 10 kPa to distill off water, pyridine, and phenol.

[0632] Thereafter, the pressure in the flask was restored with nitrogen, the internal temperature was lowered to 80° C., and 200 g of toluene was added to obtain an organic phase 1.

[0633] The obtained organic phase 1 was washed five times with 50 g of desalted water to obtain an organic phase 2. The obtained organic phase 2 was cooled to 20° C. to obtain a slurry. The obtained slurry was filtered to obtain a filter cake.

[0634] The obtained filter cake was dried using a rotary evaporator to obtain 31 g of bisphenol A. The purity of the obtained bisphenol A was 99.8% by mass.

[0635] [Example 8-2]

[0636] The sodium chloride of the reagent and water (desalted water) were mixed so that the concentration of sodium chloride became 4% by mass to obtain a 4% by mass sodium chloride aqueous solution (makeup sodium chloride aqueous solution). In Example 8-1, the same method as in Example 8-1 was used except that the makeup sodium chloride aqueous solution (29 g) was used instead of the neutralization wastewater (29 g).

[0637] The composition of a portion of the obtained reaction solution was confirmed by high performance liquid chromatography, and the result showed that bisphenol A was 14.6 mass % (14.6÷100×351g=51.2g, decomposition rate of polycarbonate resin 51.2g÷228g / mol÷0.315mol×100=71.3mol%).

[0638] [Example 8-3]

[0639] In Example 8-1, the same procedures as in Example 8-1 were carried out except that water (desalted water) (29 g) was used instead of the neutralized wastewater (29 g).

[0640] The composition of a portion of the obtained reaction solution was confirmed by high performance liquid chromatography, and the result showed that bisphenol A was 14.2 mass % (14.2÷100×351g=49.8g, decomposition rate of polycarbonate resin 49.8g÷228g / mol÷0.315mol×100=69.3mol%).

[0641] Table 7 also shows the types of catalysts and organic solvents, the use of water, sodium chloride, and wastewater, and the reaction rates (polycarbonate resin decomposition rates) for Examples 8-1 to 8-3. Table 7 shows that the combined use of pyridine, phenol, water, and sodium chloride improves the polycarbonate resin decomposition rate compared to when no sodium chloride is used. Furthermore, it is clear that wastewater from a diphenyl carbonate facility can be used. This allows for wastewater recycling, reducing environmental impact.

[0642] [Table 7]

[0643] Example 8-1 Example 8-2 Example 8-3 catalyst Pyridine Pyridine Pyridine organic solvents phenol phenol phenol water have have have Sodium chloride have have none Utilization of neutralized wastewater have none none Response rate 75.7％ 71.3％ 69.3％

[0644] [Example 8-4]

[0645] In Example 7-1, the same procedures as in Example 7-1 were carried out except that the bisphenol A obtained in Example 8-1 was used instead of the bisphenol A obtained in Example 1-1, and the time from heating to 290° C. to completion of polymerization was changed from 120 minutes to 140 minutes.

[0646] The viscosity average molecular weight (Mv) of the obtained recycled polycarbonate resin was 26,900.

[0647] (Example 9)

[0648] [Example 9-1]

[0649] 9-1-1: Acquisition of hydrochloric acid wastewater

[0650] According to the embodiment 12 of Japanese Patent Application Laid-Open No. 2004-345883, ▲3 Production of Chlorine (Paragraphs 0055-0058) Chlorine is produced, and hydrochloric acid water continuously withdrawn from the bottom of the stripping distillation column is obtained as hydrochloric acid wastewater. The composition of the obtained hydrochloric acid wastewater is: 18% by mass of hydrogen chloride and 50% by mass of dibromophenol.

[0651] 9-1-2: Production of bisphenol (decomposition of polycarbonate resin)

[0652] In a jacketed removable flask equipped with a Dimrod condenser, a stirring blade, and a thermometer, polycarbonate resin (80 g, 0.315 mol in terms of repeating units), the hydrochloric acid wastewater obtained in 9-1-1 (300 g), and phenol (200 g) were placed under a nitrogen atmosphere at room temperature. The reaction solution was in the form of a slurry. The mass of the reaction solution was 80 g + 300 g + 200 g = 580 g. Thereafter, the temperature was raised to 80°C and the reaction was carried out for 60 minutes while maintaining the temperature at 80°C.

[0653] The composition of a portion of the obtained reaction solution was confirmed by high performance liquid chromatography, revealing 8.0 mass % of bisphenol A (8.0÷100×580g=46.4g, decomposition rate of polycarbonate resin: 46.4g÷228g / mol÷0.315mol×100=64.6mol%).

[0654] [Example 9-2]

[0655] Dibromophenol as a reagent, 35% hydrochloric acid as a reagent, and water (deionized water) were mixed so that the dibromophenol content was 50 mass ppm and the hydrogen chloride content was 18 mass % to obtain a hydrochloric acid aqueous solution (makeup hydrochloric acid waste liquid). The same procedures as in Example 9-1 were followed except that the makeup hydrochloric acid waste liquid (300 g) was used instead of the hydrochloric acid waste water (300 g).

[0656] The composition of a portion of the obtained reaction solution was confirmed by high performance liquid chromatography, and the result showed that bisphenol A was 7.7 mass % (7.7÷100×580g=44.7g, decomposition rate of polycarbonate resin 44.7g÷228g / mol÷0.315mol×100=62.2mol%).

[0657] [Example 9-3]

[0658] Using 35% hydrochloric acid and water (deionized water) as reagents, a hydrochloric acid aqueous solution containing 18% by mass of hydrogen chloride (supplemented hydrochloric acid aqueous solution) was prepared. The same procedures as in Example 9-1 were followed except that the aforementioned 18% by mass hydrochloric acid (supplemented hydrochloric acid aqueous solution) (300 g) was used instead of the hydrochloric acid wastewater (300 g).

[0659] The composition of a portion of the obtained reaction solution was confirmed by high performance liquid chromatography, and the result showed that bisphenol A was 6.9 mass % (6.9÷100×580g=40.0g, decomposition rate of polycarbonate resin 40.0g÷228g / mol÷0.315mol×100=55.7mol%).

[0660] Table 8 also shows the types of catalysts and organic solvents, the presence or absence of water, dibromophenol, and wastewater used, and the reaction rates (decomposition rates of polycarbonate resins) for Examples 9-1 to 9-3. Table 8 shows that polycarbonate resins can be decomposed using hydrochloric acid wastewater discharged from a facility for recovering hydrogen chloride, a by-product of diphenyl carbonate production. It is known that the use of hydrochloric acid wastewater allows for wastewater recycling, reducing environmental burdens. Furthermore, it is known that the presence of dibromophenol results in a higher decomposition rate for polycarbonate resins.

[0661] [Table 8]

[0662] Example 9-1 Example 9-2 Example 9-3 catalyst 18% hydrochloric acid 18% hydrochloric acid 18% hydrochloric acid organic solvents phenol phenol phenol water have have have Dibromophenol have have none Utilization of hydrochloric acid wastewater have none none Response rate 64.6％ 62.2％ 55.7％

[0663] [Example 9-4]

[0664] 600 g of toluene was added to the reaction solution obtained in Example 9-1 and the temperature was adjusted to 80° C. Then, an aqueous sodium hydroxide solution and an aqueous sodium hydrogen carbonate solution were added until the pH of the aqueous phase reached 8.5.

[0665] Thereafter, stirring was stopped, oil-water separation was performed, and the aqueous phase was taken out from the flask to obtain an organic phase 1.

[0666] The obtained organic phase 1 was transferred to a distillation apparatus equipped with a thermometer, a stirring blade, a distillation tube, and a pressure regulator. While observing the distillate amount, the internal temperature was slowly raised to 180°C and the internal pressure was slowly reduced from normal pressure to 10 kPa to distill off water, toluene, and phenol.

[0667] Thereafter, the pressure in the flask was restored with nitrogen, the internal temperature was lowered to 80° C., and 200 g of toluene was added to obtain an organic phase 2. The obtained organic phase 2 was washed five times with 50 g of deionized water to obtain an organic phase 3.

[0668] The obtained organic phase 3 was cooled to 20° C. to obtain a slurry, which was then filtered to obtain a filter cake.

[0669] The obtained filter cake was dried using a rotary evaporator to obtain 25 g of bisphenol A. The purity of the obtained bisphenol A was 99.8% by mass.

[0670] [Example 9-5]

[0671] In Example 7-1, the same procedures as in Example 7-1 were carried out except that the bisphenol A obtained in Example 9-4 was used instead of the bisphenol A obtained in Example 1-1, and the time from heating to 290° C. to completion of polymerization was changed from 120 minutes to 140 minutes.

[0672] The viscosity average molecular weight (Mv) of the obtained recycled polycarbonate resin was 27,200.

[0673] (Example 10)

[0674] [Example 10-1]

[0675] 10-1-1: Acquisition of sodium hydroxide wastewater

[0676] Phosgene was produced according to the method of Example 12 of Japanese Patent Application Laid-Open No. 2004-345883, and a portion of the caustic soda was removed from a detoxification tower in which a caustic soda aqueous solution was circulated to produce sodium hydroxide wastewater. The resulting sodium hydroxide wastewater contained 50 ppm by mass of carbon tetrachloride, 0.1% by mass of sodium chloride, and 25% by mass of sodium hydroxide.

[0677] 10-1-2: Production of bisphenol (decomposition of polycarbonate resin)

[0678] In a jacketed detachable flask equipped with a Dimrod condenser, a stirring blade, and a thermometer, polycarbonate resin (80 g, 0.315 mol in terms of repeating units), sodium hydroxide wastewater (80 g) obtained in 10-1-1 above, water (40 g), and phenol (400 g) were placed under a nitrogen atmosphere at room temperature. The reaction solution was in the form of a slurry. The mass of the reaction solution was 80 g + 80 g + 40 g + 400 g = 600 g.

[0679] Thereafter, the temperature was raised to 60°C, and the reaction was carried out for 70 minutes while maintaining the temperature at 60°C.

[0680] The composition of a portion of the obtained reaction solution was confirmed by high performance liquid chromatography, and the result showed that bisphenol A was 9.2 mass % (9.2÷100×600g=55.2g, decomposition rate of polycarbonate resin 55.2g÷228g / mol÷0.315mol×100=76.9mol%).

[0681] [Example 10-2]

[0682] In such a manner that carbon tetrachloride becomes 50 mass ppm, sodium chloride becomes 0.1 mass %, and sodium hydroxide becomes 25 mass %, the carbon tetrachloride of the reagent, the sodium chloride of the reagent, the sodium hydroxide of the reagent and water (desalted water) are mixed to obtain a sodium hydroxide aqueous solution (supplying sodium hydroxide waste liquid).

[0683] In Example 10-1, the same procedure as in Example 10-1 was carried out except that the aforementioned replenishing sodium hydroxide waste liquid (80 g) was used instead of the sodium hydroxide waste water (80 g).

[0684] The composition of a portion of the obtained reaction solution was confirmed by high performance liquid chromatography, and the result showed that bisphenol A was 8.9 mass % (8.9÷100×600g=53.4g, decomposition rate of polycarbonate resin 53.4g÷228g / mol÷0.315mol×100=74.3mol%).

[0685] [Example 10-3]

[0686] Using sodium hydroxide and water (desalted water) as reagents, a 25% by mass sodium hydroxide aqueous solution (supplementary sodium hydroxide aqueous solution) was prepared.

[0687] In Example 10-1, the same procedure as in Example 10-1 was carried out except that the aforementioned replenishment sodium hydroxide aqueous solution (80 g) was used instead of the sodium hydroxide wastewater (80 g).

[0688] The composition of a portion of the obtained reaction solution was confirmed by high performance liquid chromatography, revealing 8.5 mass % of bisphenol A (8.5÷100×600g=51.0g, decomposition rate of polycarbonate resin: 51.0g÷228g / mol÷0.315mol×100=71.0mol%).

[0689] Table 9 shows together the presence or absence of the type of catalyst and organic solvent, water, carbon tetrachloride, sodium chloride, and wastewater utilization, and the reaction rate (decomposition rate of polycarbonate resin) about Example 10-1 to Example 10-3. According to Table 9, the polycarbonate resin can be decomposed by using the sodium hydroxide wastewater discharged from the detoxification treatment equipment of the manufacturing facility of phosgene (phosgene). It is known that since sodium hydroxide wastewater can be used, the recycling of wastewater can be achieved, and the environmental burden is low. In addition, it is known that if sodium hydroxide wastewater is used, the decomposition rate of polycarbonate resin becomes higher.

[0690] [Table 9]

[0691] Example 10-1 Example 10-2 Example 10-3 catalyst NaOH NaOH NaOH organic solvents phenol phenol phenol water have have have Carbon tetrachloride have have none Sodium chloride have have none Utilization of sodium hydroxide wastewater have none none Response rate 76.9％ 74.3％ 71.0％

[0692] [Example 10-4]

[0693] In a jacketed detachable flask equipped with a Dimrod condenser, a stirring blade, and a thermometer, polycarbonate resin (80 g, 0.315 mol in terms of repeating units), sodium hydroxide wastewater (80 g) obtained in Example 10-1-1 (10-1-1), water (40 g), and phenol (400 g) were placed under a nitrogen atmosphere at room temperature. The reaction solution was in the form of a slurry. The mass of the reaction solution was 80 g + 80 g + 40 g + 400 g = 600 g.

[0694] Thereafter, the temperature was raised to 80°C, and the reaction was performed for 70 minutes while maintaining the temperature at 80°C.

[0695] The composition of a portion of the obtained reaction solution was confirmed by high performance liquid chromatography, and the result showed that bisphenol A was 11.8 mass % (11.8÷100×600g=70.8g, decomposition rate of polycarbonate resin 70.8g÷228g / mol÷0.315mol×100=98.6mol%).

[0696] After 600 g of toluene was added to the obtained reaction solution, 35% by mass hydrochloric acid was added until the pH of the aqueous phase became 8.6, whereby carbon dioxide gas was generated.

[0697] Thereafter, stirring was stopped, oil-water separation was performed, and the aqueous phase was taken out from the flask to obtain an organic phase 1.

[0698] The obtained organic phase 1 was transferred to a distillation apparatus equipped with a thermometer, a stirring blade, a distillation tube, and a pressure regulator. While observing the distillate amount, the internal temperature was slowly raised to 180°C and the internal pressure was slowly reduced from normal pressure to 10 kPa to distill off water, toluene, and phenol.

[0699] Thereafter, the pressure in the flask was restored with nitrogen, the internal temperature was lowered to 80° C., and 200 g of toluene was added to obtain an organic phase 2. The obtained organic phase 2 was washed five times with 50 g of deionized water to obtain an organic phase 3.

[0700] The obtained organic phase 3 was cooled to 20° C. to obtain a slurry, which was then filtered to obtain a filter cake.

[0701] The obtained filter cake was dried using a rotary evaporator to obtain 26 g of bisphenol A. The purity of the obtained bisphenol A was 99.8% by mass.

[0702] [Example 10-5]

[0703] In Example 7-1, the same procedures as in Example 7-1 were carried out except that the bisphenol A obtained in Example 10-4 was used instead of the bisphenol A obtained in Example 1-1.

[0704] The viscosity average molecular weight (Mv) of the obtained recycled polycarbonate resin was 26,500.

[0705] [Example 11]

[0706] In a 1L four-necked flask equipped with a thermometer, a stirrer, and a condenser, 46g of bisphenol A obtained in Example 1-1, 259g of epichlorohydrin, 100g of isopropyl alcohol, and 36g of water were placed. After heating to 40°C and uniformly dissolving them, 38g of a 48.5% by mass aqueous sodium hydroxide solution was added dropwise over 90 minutes. While adding the solution, the temperature was raised from 40°C to 65°C over 90 minutes. The reaction was then maintained at 65°C for 30 minutes to terminate the reaction. The reaction solution was transferred to a 1L separatory funnel, 69g of 65°C water was added, and the mixture was allowed to stand at 65°C for 1 hour. After standing, the aqueous phase was removed from the separated oil phase and aqueous phase, and the by-product salts and excess sodium hydroxide were removed. Subsequently, the epichlorohydrin was completely removed under reduced pressure at 150°C.

[0707] Thereafter, 102 g of methyl isobutyl ketone was added, and the mixture was heated to 65° C. and uniformly dissolved. Then, 1.4 g of a 48.5% by mass sodium hydroxide aqueous solution was added, and the mixture was reacted for 60 minutes. Then, 57 g of methyl isobutyl ketone was added, and the mixture was washed four times with 200 g of water.

[0708] Thereafter, methyl isobutyl ketone was completely removed under reduced pressure at 150° C. to obtain the epoxy resin of Example 11.

[0709] The epoxy equivalent of the obtained epoxy resin was measured in accordance with JIS K7236 (2009) and was found to be 175 g / equivalent.

[0710] [Reference Example 11c]

[0711] The epoxy resin of Reference Example 11c was obtained in the same manner as in Example 11 except that bisphenol A (manufactured by Mitsubishi Chemical Corporation) was used instead of the bisphenol A obtained in Example 1-1.

[0712] The epoxy equivalent of the obtained epoxy resin was measured in accordance with JIS K7236 (2009) and found to be 173 g / equivalent.

[0713] (Epoxy Resin Composition, Epoxy Resin Cured Product, and Evaluation of Cured Properties)

[0714] [Example 12]

[0715] The epoxy resin of Example 11, a curing agent (RIKACID MH-700, manufactured by Shin Nippon Chemical Co., Ltd.), and a curing catalyst (Curesol 2E4MZ, manufactured by Shikoku Chemical Industry Co., Ltd.) were weighed in the proportions shown in Table 10. The mixture was then stirred and mixed at room temperature until uniform, thereby obtaining an epoxy resin composition.

[0716] Two glass plates with release PET films attached were prepared, with both release PET films facing inward. The glass plates were spaced 3 mm apart to create a mold. The epoxy resin composition was injected into the mold and heated at 100°C for 3 hours and then at 140°C for 3 hours to obtain a cured epoxy resin.

[0717] The resulting cured product was cut into a cylindrical shape with a diameter of 1 cm and a thickness of 3 mm to obtain a test piece. The test piece was subjected to measurement of the linear expansion coefficients α1 and α2 using a thermomechanical analyzer (TMA: TMA / SS6100 manufactured by Seiko Instruments Inc.) in compression mode with a first heating rate of 5°C / min (30°C to 200°C), a first cooling rate of 10°C / min (200°C to 30°C), and a second heating rate of 5°C / min (30°C to 200°C).

[0718] [Reference Example 12c]

[0719] The epoxy resin of Reference Example 11, a curing agent (RIKACID MH-700, manufactured by Shin Nippon Chemical Co., Ltd.), and a curing catalyst (Curesol 2E4MZ, manufactured by Shikoku Chemicals Co., Ltd.) were weighed in the ratios shown in Table 10. The mixture was then stirred and mixed at room temperature until uniform, to obtain an epoxy resin composition.

[0720] The obtained epoxy resin composition was cured by the same method as in Example 12, and the obtained epoxy resin cured product was evaluated to determine the linear expansion coefficients α1 and α2.

[0721] [Table 10]

[0722]

[0723] [Evaluation of results]

[0724] As shown in Table 10, the epoxy resin cured material of Example 12 has a lower linear expansion coefficient and is superior in heat crack resistance than the epoxy resin cured material of Reference Example 12c.

[0725] [Reference Example 13c]

[0726] Tetraphenoxytitanium was synthesized and used according to the following procedure.

[0727] In a 500mL three-necked flask equipped with a receiver and a distillation tube, 200g (2.1 mol) of phenol and 100mL of toluene were added, and the flask was purged with nitrogen. The flask was immersed in a 100°C oil bath to obtain a uniform solution. 57g (0.2 mol) of tetraisopropoxytitanium was added thereto. The internal temperature at the bottom of the flask was maintained at 100°C, and the distillation of the generated isopropanol began. Thereafter, the internal temperature was slowly raised to 116°C, and 80mL of distillate as a mixture of isopropanol and toluene was distilled out. After adding 50mL of hexane to the obtained still residue, it was cooled to room temperature and crystallized. The precipitated red crystals were obtained by filtration and dried in a rotary evaporator equipped with an oil bath at an oil bath temperature of 140°C and a pressure of 50Torr to obtain 60g (0.1 mol) of tetraphenoxytitanium.

[0728] [Example 13]

[0729] 13-1: Synthesis of dimethyl carbonate

[0730] The synthesis of dimethyl carbonate from carbon dioxide was carried out according to the non-patent document ChemSusChem, 2013, Vol. 6, pp. 1341-1344.

[0731] In a 200mL autoclave equipped with an induction stirring blade, a pressure gauge, and a thermometer, 0.4g of cerium oxide, 10.4g of cyanopyridine, and 1.6g of methanol (1.6g÷32g / mole=50 mmol) previously calcined at 600°C were placed. At this time, the carbon dioxide obtained in Example 1-1 was introduced into the autoclave using a compressor. After three replacements, the internal pressure of the autoclave was brought to 5MPa. Thereafter, the autoclave was placed in an electric furnace and reacted at an internal temperature of 120°C for 12 hours. After the reaction, the autoclave was immersed in ice water and the internal pressure was restored to normal pressure. The obtained reaction solution was filtered to remove the cerium oxide to obtain 12.6g of a mixed solution.

[0732] A portion of the obtained mixed liquid was analyzed by gas chromatography. The result showed that dimethyl carbonate was 16.2 mass % (16.2 mass %×12.6 g=2.0 g, 2.0 g÷90 g / mol=22 mmol) and the reaction rate was 22 mmol×2÷50 mmol×100%=88%.

[0733] The above operation was performed several times to obtain 200 g of a mixed solution. The obtained mixed solution was placed in a 1 L eggplant-shaped flask and placed in an evaporator equipped with a water bath to remove the initial fraction to obtain 31 g of a main fraction. A portion of the main fraction obtained was analyzed by gas chromatography, and the dimethyl carbonate purity was 97% by mass.

[0734] 13-2: Synthesis of diphenyl carbonate

[0735] In a flask equipped with a distillation tube and a stirring blade, 31 g of the main fraction (30 g of dimethyl carbonate), 40 g of dimethyl carbonate as a reagent (70 g, 0.78 moles of dimethyl carbonate in total), 500 g of phenol (5.32 moles), and 5 g of tetraphenoxytitanium were placed. The generated methanol was distilled off together with the dimethyl carbonate under normal pressure. After distillation ceased, the pressure was reduced to 1 kPa and the temperature was gradually raised to 185°C, allowing the reaction to proceed while distilling off the dimethyl carbonate. Subsequently, the oil bath was set to 210°C to yield 11 g of diphenyl carbonate.

[0736] 13-3: Synthesis of recycled polycarbonate resin

[0737] In a 45 mL glass reaction vessel equipped with a stirrer and a distillation tube, 10.00 g (0.04 mol) of bisphenol A, 9.95 g (0.05 mol) of the diphenyl carbonate obtained above, and 18 μL of a 400 ppm by mass cesium carbonate aqueous solution were placed. The pressure in the glass reaction vessel was reduced to approximately 100 Pa, and then the atmosphere was replaced with nitrogen by returning to atmospheric pressure three times. The reaction vessel was then immersed in an oil bath at 220°C to dissolve the contents.

[0738] The stirrer was rotated at 100 revolutions per minute, and while distilling off phenol by-produced by the oligomerization reaction of bisphenol A and diphenyl carbonate in the reaction vessel, the pressure in the reaction vessel was reduced from 101.3 kPa to 13.3 kPa absolute over 40 minutes.

[0739] Next, the pressure in the reaction vessel was maintained at 13.3 kPa, and the transesterification reaction was carried out for 80 minutes while further distilling off phenol.

[0740] Thereafter, the external temperature of the reaction vessel was raised to 290° C., and the pressure in the reaction vessel was reduced from 13.3 kPa to 399 Pa absolute over 40 minutes to remove the distilled phenol to the outside of the system.

[0741] The absolute pressure in the reaction vessel was then reduced to 30 Pa to allow the polycondensation reaction to proceed. The polycondensation reaction was terminated when the stirrer in the reaction vessel reached a predetermined stirring power. The time from heating to 290°C to the completion of the polymerization was 120 minutes.

[0742] Next, the absolute pressure in the reaction vessel was returned to 101.3 kPa with nitrogen gas, and then the pressure was increased to 0.2 MPa in gauge pressure, and the polycarbonate resin was taken out from the reaction vessel to obtain a polycarbonate resin.

[0743] The viscosity average molecular weight (Mv) of the obtained polycarbonate resin was 24,800.

[0744] Industrial applicability

[0745] According to the method for producing bisphenol of the present invention, bisphenol can be obtained from waste plastics and the like by chemical recycling. Furthermore, the bisphenol can be used to produce polycarbonate resin again, which is industrially useful.

[0746] Description of Reference Numerals

[0747] 1 Diphenyl carbonate manufacturing facilities

[0748] 2 Hydrogen chloride recovery facilities

[0749] 3. Phosgene Manufacturing Facilities

[0750] 10 DPC reactor

[0751] 11 Dehydrochlorination Tower

[0752] 12 Mixing tank

[0753] 13 Neutralization Tank

[0754] 14 Washing Tank

[0755] 15, 16 distillation tower

[0756] 20 Activated carbon tower

[0757] 21 Absorption Tower

[0758] 22, 24, 32 cans

[0759] 23 Stripping Tower

[0760] 30 CDC reactor

[0761] 31 Aggregator

[0762] 33 Evaporator

[0763] 34 Pest Control Tower

[0764] 100, 102, 103 decomposition tanks

[0765] G10, G12, G20 Hydrogen Chloride Gas

[0766] G30 Crude Phosgene Gas

[0767] G31 Non-liquefied gas

[0768] G32 Waste Gas

[0769] G13 diphenyl carbonate

[0770] L10 Reaction solution containing diphenyl carbonate

[0771] L11 Reaction liquid after dehydrochlorination treatment

[0772] L12, L31 sodium hydroxide aqueous solution

[0773] L13, L16 oil phase

[0774] L14 aqueous phase (neutralized wastewater)

[0775] L15, L20 water

[0776] L17 aqueous phase

[0777] L21, L24, L26 dilute hydrochloric acid

[0778] L23 concentrated hydrochloric acid

[0779] L25 Hydrochloric acid wastewater

[0780] L30 Phosgene

[0781] L32 Sodium hydroxide waste liquid

[0782] L100, L102, L103 solutions containing bisphenol A

[0783] CDC, G1 Phosgene gas

[0784] CO carbon monoxide gas

[0785] CL2 chlorine

[0786] H2O water

[0787] PC polycarbonate resin

[0788] PL phenol

[0789] PRD Pyridine

[0790] Acid

[0791] base

Claims

1. A method for producing bisphenol, wherein: Decompose polycarbonate resin in the presence of aromatic monohydric alcohol, water and catalyst. The catalyst is any one selected from the group consisting of alkali metal hydroxides, alkali metal carbonates, alkylamines, nitrogen-containing heterocyclic compounds and acids. The aromatic monohydric alcohol is any one selected from the group consisting of phenol, cresol, and xylenol.

2. The method for producing bisphenol according to claim 1, wherein The alkali metal hydroxide is sodium hydroxide or potassium hydroxide.

3. The method for producing bisphenol according to claim 1, wherein The alkylamine is represented by the following formula (I), Where R A represents an alkyl group having 1 to 3 carbon atoms, R B ~R C Each independently represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.

4. The method for producing bisphenol according to claim 1, wherein The alkylamine is a tertiary amine.

5. The method for producing bisphenol according to claim 3, wherein The alkylamine is a tertiary amine.

6. The method for producing bisphenol according to claim 1, wherein The acid is any one selected from the group consisting of hydrochloric acid, sulfuric acid, phosphoric acid, and sulfonic acid.

7. The method for producing bisphenol according to claim 1, wherein The catalyst comprises a nitrogen-containing heterocyclic compound, The polycarbonate resin is decomposed in the presence of the aromatic monohydric alcohol, the water, the catalyst, and an alkali metal chloride.

8. The method for producing bisphenol according to claim 1, wherein The nitrogen-containing heterocyclic compound is pyridine.

9. The method for producing bisphenol according to claim 7, wherein The nitrogen-containing heterocyclic compound is pyridine.

10. The method for producing bisphenol according to claim 7, wherein The alkali metal chloride is sodium chloride.

11. The method for producing bisphenol according to any one of claims 1 to 10, wherein The reaction temperature for decomposing the polycarbonate resin is 110° C. or lower.

12. The method for producing bisphenol according to any one of claims 1 to 10, wherein The polycarbonate resin is decomposed in a slurry-like reaction liquid containing the polycarbonate resin, the aromatic monohydric alcohol, the water, and the catalyst.

13. The method for producing bisphenol according to any one of claims 1 to 10, wherein The mass ratio of the water to the aromatic monohydric alcohol is 0.001 or more and 10 or less.

14. The method for producing bisphenol according to claim 1, wherein The catalyst comprises hydrochloric acid, The polycarbonate resin is decomposed in the co-presence of the aromatic monohydric alcohol, the water, the catalyst, and bromophenols.

15. The method for producing bisphenol according to claim 1, wherein The catalyst comprises sodium hydroxide, The polycarbonate resin is decomposed in the co-presence of the aromatic monohydric alcohol, the water, the catalyst, and sodium chloride and / or carbon tetrachloride.

16. The method for producing bisphenol according to any one of claims 1 to 10, 14 and 15, wherein The bisphenol is 2,2-bis(4-hydroxyphenyl)propane.

17. The method for producing bisphenol according to claim 1 or 7, wherein When a diaryl carbonate is produced by a method comprising the following steps (a1), (b1), (b2), and (b3), the neutralization wastewater removed in step (b1) is used for decomposition of the polycarbonate resin. Step (a1): a step of reacting phosgene and an aromatic monohydric alcohol in the presence of a nitrogen-containing heterocyclic compound to obtain a reaction solution containing a diaryl carbonate Step (b1): neutralizing the reaction solution containing the diaryl carbonate obtained in step (a1) with an aqueous alkali metal hydroxide solution, separating the reaction solution into an oil phase containing the aromatic diaryl carbonate and an aqueous phase containing the nitrogen-containing heterocyclic compound and the alkali metal chloride, and removing the aqueous phase as neutralization wastewater. Step (b2): a step of washing the oil phase obtained in step (b1) with water Step (b3): ​​a step of obtaining diaryl carbonate from the oil phase after step (b2).

18. The method for producing bisphenol according to claim 17, wherein The alkali metal chloride in step (b1) is sodium chloride, The alkali metal hydroxide aqueous solution in the step (b1) is a sodium hydroxide aqueous solution.

19. The method for producing bisphenol according to claim 1 or 14, wherein In the production of diaryl carbonate and recovery of by-produced hydrogen chloride comprising the following steps (a1), (c1), (c2), and (c3), the hydrochloric acid wastewater removed in step (c3) is used for decomposition of the polycarbonate resin. Step (a1): a step of reacting phosgene and an aromatic monohydric alcohol in the presence of a nitrogen-containing heterocyclic compound to obtain a reaction solution containing a diaryl carbonate Step (c1): The step of supplying the hydrogen chloride produced as a by-product in step (a1) to an absorption tower and allowing it to be absorbed by water or dilute hydrochloric acid to obtain concentrated hydrochloric acid. Step (c2): distilling concentrated hydrochloric acid in a stripping tower, recovering hydrogen chloride gas from the top of the tower, and recovering hydrochloric acid from the bottom of the tower Step (c3): a step of removing a portion of the hydrochloric acid recovered from the bottom of the tower as hydrochloric acid waste water out of the system and circulating the remaining hydrochloric acid in the absorption tower of step (c1).

20. The method for producing bisphenol according to claim 1 or 15, wherein In the production of phosgene and treatment of unliquefied gas comprising the following steps (d1) to (d4), the sodium hydroxide wastewater removed in step (d4) is used for decomposition of the polycarbonate resin. Step (d1): a step of obtaining phosgene gas from chlorine and carbon monoxide Step (d2): Cooling the phosgene gas obtained in step (d1) to obtain liquefied phosgene Step (d3): a step of contacting the circulating sodium hydroxide aqueous solution with the unliquefied gas in step (d2) to decompose and discharge the phosgene in the unliquefied gas. Step (d4): a step of removing a portion of the circulating sodium hydroxide aqueous solution as sodium hydroxide wastewater.

21. A method for producing a recycled polycarbonate resin, wherein: The production method comprises the steps of obtaining bisphenol by the method for producing bisphenol according to any one of claims 1 to 20, and producing a recycled polycarbonate resin using a bisphenol raw material containing the bisphenol.

22. A method for producing carbon dioxide, wherein: The production method comprises a step of obtaining bisphenol by the method for producing bisphenol according to any one of claims 1 to 20, and a step of recovering carbon dioxide generated in the step.

23. A method for producing a carbonic acid diester, wherein: The production method includes the steps of obtaining carbon dioxide by the method for producing carbon dioxide according to claim 22, and producing a carbonic acid diester using the carbon dioxide. 24 . The method for producing a carbonic acid diester according to claim 23 , comprising the step of reacting the carbon dioxide containing the carbon dioxide with an aliphatic monohydric alcohol.

25. The method for producing a carbonic acid diester according to claim 23, wherein Carbon monoxide is obtained from carbon dioxide containing the carbon dioxide and coke, the obtained carbon monoxide is reacted with chlorine to obtain phosgene, and the obtained phosgene is reacted with an aromatic monohydric alcohol to obtain the carbonic diester.

26. A method for producing a recycled polycarbonate resin, wherein: The production method comprises the steps of obtaining a carbonate diester by the method for producing a carbonate diester according to any one of claims 23 to 25, and producing a recycled polycarbonate resin using a carbonate diester raw material containing the carbonate diester.

27. A method for producing an epoxy resin, wherein: The production method includes the steps of obtaining bisphenol by the method for producing bisphenol according to any one of claims 1 to 20, and producing an epoxy resin using the bisphenol.

28. The method for producing an epoxy resin according to claim 27, wherein The epoxy resin is further reacted with a polyhydroxy compound raw material.

29. A method for producing a cured epoxy resin, wherein: The production method comprises the steps of obtaining an epoxy resin by the method for producing an epoxy resin according to claim 27 or 28, and curing an epoxy resin composition containing the epoxy resin and a curing agent to obtain a cured epoxy resin.

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