Method for producing bisphenol, method for producing recycled polycarbonate resin, method for producing carbon dioxide, method for producing carbonate diester, method for producing epoxy resin, and method for producing cured epoxy resin

Abstract

Provided is a production method for a bisphenol or the like by using a chemical recycling method that is moderate, has a small environmental load, and enables efficient degradation of a polycarbonate resin. Provided is a method for producing a recycled polycarbonate resin or the like using a useful substance such as the bisphenol or the like.　This bisphenol production method involves degrading a polycarbonate resin in the presence of an aromatic monoalcohol, water, and a catalyst. This carbon dioxide production method involves recovering carbon dioxide generated in said bisphenol production method. In this carbonic diester production method, said carbon dioxide is used. In this recycled polycarbonate resin production method, said bisphenol and / or said carbonic diester is used. In this epoxy resin production method and this epoxy resin cured product production method, said bisphenol is used.

Description

[Technical Field]

[0001] The present invention relates to a method for producing bisphenol. More specifically, the present invention relates to a method for producing bisphenol by utilizing the decomposition of polycarbonate resin. The present invention also relates to a method for producing recycled polycarbonate resin using bisphenol obtained by the method for producing bisphenol. The present invention also relates to a method for producing carbon dioxide and a method for producing a carbonate diester by utilizing the decomposition of polycarbonate resin. The present invention also relates to a method for producing an epoxy resin and a method for producing a cured epoxy resin. [Background technology]

[0002] Plastic is easily accessible, durable, and inexpensive, leading to mass production not only in Japan but around the world. Because much of this plastic is "disposable," it is not properly disposed of and some ends up in the environment. Specifically, plastic waste flows from rivers into the ocean, where it degrades due to waves and ultraviolet light, becoming smaller than 5 mm. These tiny pieces of plastic waste are called microplastics. Animals and fish accidentally ingest these microplastics. Plastic waste thus has a significant impact on ecosystems, and in recent years, the marine plastic problem has become a global concern. Polycarbonate resin, 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 method for recycling polycarbonate resin is chemical recycling, in which polycarbonate resin is chemically decomposed back to bisphenol, which can then be reused. Hydrolysis is also known as a method for decomposing polycarbonate resin. Known hydrolysis methods include placing polycarbonate resin and an alkaline aqueous solution in a pressure vessel and hydrolyzing the resin under high temperature and pressure (Patent Document 1). Another known method involves dissolving polycarbonate resin in a chlorinated hydrocarbon solvent and adding an alkali metal hydroxide as a basic catalyst to hydrolyze the resin (Patent Document 2).

[0004] Another known method for decomposing polycarbonate resins is phenollysis, which involves decomposing polycarbonate resins to produce diphenyl carbonate and bisphenol A (Patent Documents 3 and 4). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Special Publication No. 40-16536 [Patent Document 2] International Publication No. 2006 / 114893 [Patent Document 3] Japanese Patent Application Publication No. 7-196582 [Patent Document 4] Japanese Patent Application Publication No. 7-316280 [Patent Document 5] Japanese Patent Application Laid-Open No. 2005-97568 [Patent Document 6] Japanese Patent Application Laid-Open No. 2004-345883 [Patent Document 7] Japanese Patent Application Laid-Open No. 2006-144023 Summary of the Invention [Problem to be solved by the invention]

[0006] Chemical recycling of polycarbonate resin is an important solution to the marine plastic problem. Water is used in the hydrolysis of polycarbonate resin. However, if the hydrolysis temperature is above 100°C (the boiling point of water at normal pressure), the vapor pressure of water creates high-pressure conditions. For example, in Example 1 of Patent Document 1, polycarbonate resin is decomposed at 180 to 185°C. However, the use of water creates high-pressure conditions, necessitating the use of a pressure-resistant vessel. On the other hand, in a method for hydrolyzing polycarbonate resin at near room temperature, a chlorinated hydrocarbon solvent is used as a solvent to dissolve the polycarbonate resin. For example, in Example 1 of Patent Document 2, polycarbonate resin is hydrolyzed at 40°C, but methylene chloride is used as the solvent. Chlorinated hydrocarbon solvents such as methylene chloride are chemically stable and therefore flame-retardant compounds. Therefore, unless waste disposal is carried out appropriately at high temperatures, dioxin generation is a problem.

[0007] Furthermore, in the phenolization of polycarbonate resin, phenol is used to depolymerize the polycarbonate resin, and because phenol has a high boiling point, the phenolization temperature can be set to 100°C or higher. For example, according to Example 1 of Patent Document 3, polycarbonate resin is phenolized at 160°C using an amine as a catalyst to obtain diphenyl carbonate and bisphenol A. However, in order to purify bisphenol A from the produced diphenyl carbonate, it is necessary to separate it by distillation at high temperature under strict vacuum conditions, which requires harsh conditions and involves complex purification procedures.

[0008] As such, all conventional chemical recycling methods for polycarbonate resin require harsh conditions or conditions that place a heavy burden on the environment, and further improvements have been required.

[0009] Meanwhile, diphenyl carbonate, a raw material for polycarbonate resin, is produced from carbonyl chloride and phenol in the presence of an alkaline catalyst such as pyridine, neutralized with an alkaline aqueous solution, and then obtained by distillation (Patent Document 5). The neutralized wastewater discharged during neutralization is treated in a wastewater treatment process and then treated with activated sludge, but there was a problem in that the discharge of a large amount of neutralized wastewater placed a heavy load on the activated sludge.

[0010] Furthermore, in the reaction between carbonyl chloride and phenol, hydrogen chloride is produced as a by-product in addition to diphenyl carbonate. The hydrogen chloride produced together with diphenyl carbonate is first absorbed in water to form hydrochloric acid, which then becomes 18% by mass hydrochloric acid together with the hydrogen chloride stripped in a stripping distillation column. The stripped hydrogen chloride is converted to chlorine in the next oxidation step (Patent Document 6). This 18% by mass hydrochloric acid contains sulfur components. To prevent the sulfur components from concentrating in the system, a portion of the product is discarded as hydrochloric acid wastewater.

[0011] Furthermore, carbonyl chloride, a raw material for diphenyl carbonate, is synthesized by reacting chlorine with carbon monoxide. According to Patent Document 7, unliquefied gas that could not be liquefied during liquefaction is detoxified with an aqueous sodium hydroxide solution (aqueous caustic soda solution), and after the carbonyl chloride (phosgene) contained in the unliquefied gas is completely decomposed, it is released into the atmosphere as waste gas. Because complete decomposition of carbonyl chloride is necessary for safety reasons, a large amount of aqueous sodium hydroxide solution with a high concentration is used in the detoxification treatment of unliquefied gas. This high-concentration aqueous sodium hydroxide solution, in large quantities, is problematic in that it is disposed of as sodium hydroxide wastewater.

[0012] From the perspective of reducing the environmental burden, it is also necessary to make effective use 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 carbonyl chloride.

[0013] 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 mild, has a small environmental impact, and can efficiently decompose polycarbonate resin.

[0014] A further object of the present invention is to provide a method for producing a recycled polycarbonate resin using the obtained bisphenol.

[0015] Another object of the present invention is to provide a method for producing carbon dioxide utilizing the above-mentioned method for producing bisphenol, and a method for producing a carbonate diester using the carbon dioxide obtained.

[0016] Another object of the present invention is to provide a method for producing an epoxy resin, and a method for producing a cured epoxy resin product using the obtained epoxy resin. [Means for solving the problem]

[0017] As a result of intensive research aimed at solving the above-mentioned problems, the present inventors have discovered a method for decomposing polycarbonate resin in the presence of an aromatic monoalcohol such as phenol or cresol, water, and a catalyst. They have also discovered a method for producing bisphenol and carbon dioxide using the polycarbonate resin decomposition method. They have also discovered a production method for producing useful substances such as recycled polycarbonate resin using the resulting bisphenol or carbon dioxide.

[0018] That is, the present invention relates to the following inventions. <1> A method for producing bisphenols by decomposing a polycarbonate resin in the presence of an aromatic monoalcohol, water and a catalyst. <2> The catalyst is any one selected from the group consisting of alkali metal hydroxides, alkali metal carbonates, alkylamines, nitrogen-containing heterocyclic compounds, and acids. <1> 1. A method for producing bisphenol according to claim 1. <3> The alkali metal hydroxide is sodium hydroxide or potassium hydroxide. <2> 1. A method for producing bisphenol according to claim 1. <4> The alkylamine is represented by the following formula (I): <2> 1. A method for producing bisphenol according to claim 1. [ka] In the formula, R A represents an alkyl group having 1 to 3 carbon atoms, and R B ~R C each independently represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. <5> The alkylamine is a tertiary amine. <2> or <4> 1. A method for producing bisphenol according to claim 1. <6> The acid is any one selected from the group consisting of hydrochloric acid, sulfuric acid, phosphoric acid, and sulfonic acid. <2> 1. A method for producing bisphenol according to claim 1. <7> the catalyst contains a nitrogen-containing heterocyclic compound, and the polycarbonate resin is decomposed in the presence of an alkali metal chloride in addition to the aromatic monoalcohol, the water, and the catalyst; <1> 1. A method for producing bisphenol according to claim 1. <8> The nitrogen-containing heterocyclic compound is a pyridine. <2> or <7> 1. A method for producing bisphenol according to claim 1. <9> The alkali metal chloride is sodium chloride. <7> 1. A method for producing bisphenol according to claim 1. <10> The reaction temperature for decomposing the polycarbonate resin is 110°C or less. <1> from <9> 1. The method for producing bisphenol according to claim 1, <11> decomposing the polycarbonate resin in a slurry-like reaction liquid containing the polycarbonate resin, the aromatic monoalcohol, the water, and the catalyst; <1> from <10> 1. The method for producing bisphenol according to claim 1, <12> the mass ratio of the water to the aromatic monoalcohol is 0.001 or more and 10 or less; <1> from <11> 1. The method for producing bisphenol according to claim 1, <13> the catalyst contains hydrochloric acid, and the polycarbonate resin is decomposed in the coexistence of the aromatic monoalcohol, the water, the catalyst, and a bromophenol; <1> 1. A method for producing bisphenol according to claim 1. <14> the catalyst contains sodium hydroxide, and the polycarbonate resin is decomposed in the presence of sodium chloride and / or carbon tetrachloride in addition to the aromatic monoalcohol, the water, and the catalyst; <1> 1. A method for producing bisphenol according to claim 1. <15> The aromatic monoalcohol is any one selected from the group consisting of phenol, cresol, and xylenol. <1> from <14> 1. The method for producing bisphenol according to claim 1, <16> The bisphenol is 2,2-bis(4-hydroxyphenyl)propane. <1> from <15> 1. The method for producing bisphenol according to claim 1, <17> A method for producing diaryl carbonate by the following steps (a1), (b1), (b2) and (b3), wherein neutralization wastewater removed in step (b1) is used for decomposing the polycarbonate resin; <1> or <7> 1. A method for producing bisphenol according to claim 1. Step (a1): A step of reacting carbonyl chloride with an aromatic monoalcohol in the presence of a nitrogen-containing heterocyclic compound to obtain a reaction solution containing a diaryl carbonate. Step (b1): A step of neutralizing the reaction solution containing the diaryl carbonate obtained in step (a1) with an aqueous alkali metal hydroxide solution, separating the mixture into an oil phase containing the aromatic diaryl and an aqueous phase containing the nitrogen-containing heterocyclic compound and an alkali metal chloride, and then 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 alkali metal chloride in the step (b1) is sodium chloride, and the alkali metal hydroxide aqueous solution in the step (b1) is a sodium hydroxide aqueous solution. <17> 1. A method for producing bisphenol according to claim 1. <19> A method for producing diaryl carbonate and recovering hydrogen chloride produced as a by-product, comprising the steps (a1), (c1), (c2) and (c3) below, wherein the hydrochloric acid wastewater removed in the step (c3) is used for decomposing the polycarbonate resin. <1> or <13> 1. A method for producing bisphenol according to claim 1. Step (a1): A step of reacting carbonyl chloride with an aromatic monoalcohol in the presence of a nitrogen-containing heterocyclic compound to obtain a reaction solution containing a diaryl carbonate. Step (c1): A step of supplying the hydrogen chloride by-produced in step (a1) to an absorption tower and absorbing it in water or dilute hydrochloric acid to obtain concentrated hydrochloric acid. Step (c2): A step of distilling concentrated hydrochloric acid in a stripper column, recovering hydrogen chloride gas from the top of the column, and recovering hydrochloric acid from the bottom of the column. Step (c3): A step of removing a part of the hydrochloric acid recovered from the bottom of the column to the outside of the system as hydrochloric acid waste water, and circulating the remaining hydrochloric acid to the absorption column of step (c1). <20> In the production of carbonyl chloride and the treatment of unliquefied gas, which comprises the following steps (d1) to (d4), the sodium hydroxide wastewater removed in step (d4) is used for decomposing the polycarbonate resin. <1> or <14> 1. A method for producing bisphenol according to claim 1. Step (d1): A step of obtaining carbonyl chloride gas from chlorine and carbon monoxide Step (d2): A step of cooling the carbonyl chloride gas obtained in step (d1) to obtain liquefied carbonyl chloride. Step (d3): A step of contacting the circulating aqueous sodium hydroxide solution with the unliquefied gas that was not liquefied in step (d2) to decompose carbonyl chloride in the unliquefied gas, and then discharging the decomposed carbonyl chloride. Step (d4): A step of removing a portion of the circulating aqueous sodium hydroxide solution as sodium hydroxide wastewater. <21> The aforementioned <1> from <20> 1. A method for producing a recycled polycarbonate resin, comprising producing a recycled polycarbonate resin using a bisphenol raw material containing bisphenol obtained by the method for producing bisphenol according to any one of the above. <22> The aforementioned <1> from <20> 1. A method for producing carbon dioxide, comprising recovering carbon dioxide produced by the method for producing bisphenol according to any one of the above. <23> The aforementioned <22> 2. A method for producing a carbonic acid diester, comprising producing a carbonic acid diester using carbon dioxide obtained by the method for producing carbon dioxide according to claim 1. <24> The method further comprises reacting the carbon dioxide containing carbon dioxide with an aliphatic monoalcohol. <23> 2. A method for producing a carbonate diester according to claim 1. <25> obtaining carbon monoxide from the carbon dioxide containing carbon dioxide and coke, reacting the obtained carbon monoxide with chlorine to obtain carbonyl chloride, and reacting the obtained carbonyl chloride with an aromatic monoalcohol to obtain the carbonate diester; <23> 2. A method for producing a carbonate diester according to claim 1. <26> The aforementioned <23> from <25> 1. A method for producing a recycled polycarbonate resin, comprising producing a recycled polycarbonate resin using a carbonate diester raw material containing the carbonate diester obtained by the method for producing a carbonate diester according to any one of the above items. <27> The aforementioned <1> from <20> 1. A method for producing an epoxy resin, comprising producing an epoxy resin using bisphenol obtained by the method for producing bisphenol according to any one of the above items. <28> The epoxy resin is further reacted with a polyhydric hydroxy compound raw material. <27> A method for producing an epoxy resin according to claim 1. <29> The aforementioned <27> or <28> 1. A method for producing a cured epoxy resin product, comprising curing an epoxy resin composition containing the epoxy resin obtained by the method for producing an epoxy resin according to claim 1 and a curing agent to obtain a cured epoxy resin product. [Effects of the Invention]

[0019] According to the present invention, there is provided a method for producing bisphenol by utilizing a chemical recycling method that can efficiently decompose polycarbonate resin under mild conditions with little environmental impact. Furthermore, the method for producing bisphenol of the present invention also simplifies the operations for recovering and purifying bisphenol.

[0020] Furthermore, according to the present invention, it is possible to effectively utilize wastewater such as neutralization wastewater discharged during the production of diphenyl carbonate, hydrochloric acid wastewater discharged during the recovery of by-produced hydrogen chloride, and sodium hydroxide wastewater discharged during the detoxification treatment of unliquefied gas generated during the production of carbonyl chloride.

[0021] Furthermore, the present invention provides a method for producing a recycled polycarbonate resin using the obtained bisphenol.

[0022] The present invention also provides a method for producing carbon dioxide using the above-mentioned method for producing bisphenol, and a method for producing a carbonate diester using the carbon dioxide obtained.

[0023] The present invention also provides a method for producing an epoxy resin, and a method for producing a cured epoxy resin product using the obtained epoxy resin. [Brief explanation of the drawings]

[0024] [Figure 1] FIG. 1 is a flow diagram illustrating an example of a method for producing bisphenol of the present invention using wastewater. [Figure 2] FIG. 1 is a flow diagram illustrating an example of a method for producing bisphenol of the present invention using wastewater. [Figure 3] FIG. 1 is a flow diagram illustrating an example of a method for producing bisphenol of the present invention using wastewater. DETAILED DESCRIPTION OF THE INVENTION

[0025] The following describes in detail an embodiment of the present invention, but the description of the constituent elements described below is one example of an embodiment of the present invention, and the present invention is not limited to the following description as long as it does not deviate from the gist of the present invention. Note that when the expression "to" is used in this specification, it is used as an expression that includes the numerical values ​​or physical property values ​​before and after it.

[0026] <Bisphenol manufacturing method> The present invention relates to a method for producing bisphenols (hereinafter, sometimes referred to as the "method for producing bisphenols of the present invention"), in which a polycarbonate resin is decomposed in the presence of an aromatic monoalcohol, water, and a catalyst.

[0027] The method for producing bisphenol of the present invention utilizes a chemical recycling method in which polycarbonate resin is decomposed in the presence of an aromatic monoalcohol, water and a catalyst. The present inventors have found that by using an aromatic monoalcohol and water in combination in the presence of a catalyst, polycarbonate resin can be decomposed into bisphenol and carbon dioxide, and / or a bisphenol salt and a metal carbonate salt, even under mild conditions at about the boiling point of water (normal pressure, about 100°C). Furthermore, they have found that by using an aromatic monoalcohol and water in combination, the decomposition reaction of polycarbonate resin occurs at a high reaction rate, even without completely dissolving the polycarbonate resin using a solvent that has high solubility for polycarbonate resin, such as a halogenated solvent. Furthermore, they have found that carbon dioxide and metal carbonate salts produced by the decomposition of polycarbonate resin can be easily removed from the system, facilitating the recovery and purification of bisphenol. The present invention is based on these findings.

[0028] By using an aromatic monoalcohol in combination with water, solvolysis (for example, phenollysis) and hydrolysis reactions by the aromatic monoalcohol occur within the system, making the polycarbonate resin more susceptible to decomposition even under mild conditions. Furthermore, diaryl carboxylate, which is produced by the reaction of the polycarbonate resin with the aromatic monoalcohol, is hydrolyzed to carbon dioxide, which can be easily discharged outside the system, and this is thought to facilitate purification.

[0029] (Polycarbonate resin) The polycarbonate resin used in the method for producing bisphenol of the present invention comprises a polymer composition containing a carbonate bond (-OC(=O)-O-). Specifically, the polycarbonate resin used in the method for producing bisphenol of the present invention comprises a polymer containing a structural unit derived from bisphenol, represented by general formula (1).

[0030] [ka]

[0031] R 1 ~R 4 The substituents of each independently include a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, an aryl group, etc. Examples thereof include 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 i-propyl group, an n-butyl group, an i-butyl group, a t-butyl group, an n-pentyl group, an i-pentyl 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 i-propoxy group, an n-butoxy group, an i-butoxy group, and a t-butoxy group. Examples of such groups include an n-pentyloxy group, an i-pentyloxy group, an n-hexyloxy group, an n-heptyloxy group, an n-octyloxy group, an n-nonyloxy group, an n-decyloxy group, an n-undecyloxy group, an n-dodecyloxy 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.

[0032] R 5 and R 6The substituents of each independently include a hydrogen atom, an alkyl group, an alkoxy group, an aryl group, etc. Examples thereof include a hydrogen atom, a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, an i-butyl group, a t-butyl group, an n-pentyl group, an i-pentyl 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 i-propoxy group, an n-butoxy group, an i-butoxy group, a t-butoxy ... i-pentyl group, an i-pentyl group, an i-pentyl group, an i-pentyl group, an i-pentyl group, an i-pentyl group, an i-pentyl group, an i-pentyl group, an i-pentyl group, an i-pentyl group, an i-pentyl group, an i-pentyl group, an i-pentyl group, an i-pentyl group, an i-pentyl group, an i-pentyl group, an i-pentyl group, an i-pentyl group, an i-pentyl group, an i-pentyl group, an i-pentyl group, an i-pentyl group, an i-pentyl group, an i-pentyl group, an i-pentyl group, Examples of such an alkyl group include an n-butyloxy group, an i-pentyloxy group, an n-hexyloxy group, an n-heptyloxy group, an n-octyloxy group, an n-nonyloxy group, an n-decyloxy group, an n-undecyloxy group, an n-dodecyloxy 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.

[0033] R 5 and R 6 may be bonded or bridged to each other between two groups, and examples thereof include cyclopropylidene, cyclobutylidene, cyclopentylidene, cyclohexylidene, 3,3,5-trimethylcyclohexylidene, cycloheptylidene, cyclooctylidene, cyclononylidene, cyclodecylidene, cycloundecylidene, cyclododecylidene, fluorenylidene, xanthonylidene, and thioxanthonylidene.

[0034] Among them, R in the above general formula (1) 1 ~R 4 is a hydrogen atom, and R 5 , R 6 is a methyl group (hereinafter, may be referred to as "bisphenol A type polycarbonate resin") is preferably used as a raw material.

[0035] In the general formula (1), n ​​is not particularly limited, but is, for example, 2 to 1,000.

[0036] Furthermore, the polycarbonate resin may be not only a polycarbonate resin alone, but also a composition containing a resin other than polycarbonate resin, such as a copolymer or polymer alloy. Examples of compositions containing a resin other than polycarbonate resin include polycarbonate / polyester copolymer, polycarbonate / polyester alloy, polycarbonate / polyarylate copolymer, and polycarbonate / polyarylate alloy. When using a composition containing a resin other than polycarbonate resin, it is preferable that the main component is polycarbonate resin (the composition contains 50% by mass or more of polycarbonate resin).

[0037] The polycarbonate resin may be a mixture of two or more different polycarbonate resins, and a polycarbonate resin alone may be simply called polycarbonate.

[0038] From the viewpoint 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 monoalcohol, water, and a catalyst, the polycarbonate resin contained in the waste plastics can be decomposed to produce bisphenol or a salt thereof. Polycarbonate resins are used by being molded into various molded products, such as optical components such as headlamps, optical recording media such as optical disks, etc. As waste plastics containing polycarbonate resins, offcuts, defective products, used molded products, etc., generated when polycarbonate resins are molded into these molded products can be used. Waste plastics may be used after appropriate cleaning, crushing, pulverization, etc. Methods for crushing waste plastics include coarse crushing using a jaw crusher or gyratory crusher to crush to 20 cm or less, medium crushing using a gyratory crusher, cone crusher, or mill to crush to 1 cm or less, and pulverization using a mill to crush to 1 mm or less. It is sufficient to reduce the size of the waste plastics to a size that can be fed to the decomposition tank. Furthermore, if the waste plastic is thin plastic, such as CDs or DVDs, it can be shredded using a shredder or the like and fed to the decomposition tank. Furthermore, portions made of components other than polycarbonate resin, such as other resins in copolymers or polymer alloys, or the surface and back layers of optical disks, may be removed before use.

[0039] (aromatic monoalcohol) One of the features of the method for producing bisphenols of the present invention is the use of an aromatic monoalcohol, which 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. Examples of cresol include ortho-cresol, meta-cresol, and para-cresol, as well as isomeric mixtures containing one or more of these. Since cresols are easily supplied to the decomposition tank if they are liquid at around 30°C, ortho-cresol, meta-cresol, an isomeric mixture of meta-cresol and para-cresol, or an isomeric mixture of ortho-cresol, meta-cresol and para-cresol is preferred. 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 available industrially at low cost.

[0040] If the mass ratio of aromatic monoalcohol to polycarbonate resin (mass of aromatic monoalcohol / mass of polycarbonate resin) is small, the amount of solid (polycarbonate resin) relative to the liquid increases, resulting in a high slurry concentration and poor mixing. Therefore, this mass ratio is preferably 0.01 or more, more preferably 0.03 or more, and even more preferably 0.05 or more. Furthermore, if this mass ratio is large, 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.

[0041] (water) One of the features of the method for producing bisphenol of the present invention is that water is used together with an aromatic monoalcohol. If the mass ratio of water to polycarbonate resin (mass of water / mass of polycarbonate resin) is small, the decomposition rate decreases, the decomposition time increases, and efficiency tends to decrease. Therefore, the mass ratio is preferably 0.1 or more, more preferably 0.5 or more, and even more preferably 1.0 or more. Furthermore, if the mass ratio is large, the production efficiency of bisphenol and carbon dioxide tends to decrease. Therefore, the mass ratio is preferably 100 or less, more preferably 70 or less, and even more preferably 50 or less.

[0042] The mass ratio of water to aromatic monoalcohol (mass of water / mass of aromatic monoalcohol) is preferably 0.001 or more, more preferably 0.05 or more. The mass ratio is preferably 20 or less, more preferably 15 or less. The mass ratio may be 10 or less, 5 or less, 1 or less, 0.5 or less, 0.2 or less, etc. If the mass ratio of water to aromatic monoalcohol is low, the decomposition rate decreases and the decomposition time becomes long, while if the mass ratio is high, the volume of the reaction solution increases, resulting in inefficiency.

[0043] (catalyst) One of the features of the bisphenol production method of the present invention is that a catalyst is further used. The catalyst may be any catalyst capable of promoting the decomposition of the polycarbonate resin, and a base or an acid may be used. 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. Of these, any one selected from the group consisting of alkali metal hydroxides, alkali metal carbonates, alkylamines, nitrogen-containing heterocyclic compounds, and acids is preferred.

[0044] [Alkali metal hydroxides] Alkali metal hydroxides are compounds containing alkali metal ions (M + ) and hydroxide ions (OH - ) and is a compound represented by MOH (M represents an alkali metal atom). As the alkali metal hydroxide, sodium hydroxide or potassium hydroxide is preferred.

[0045] If the mass ratio of alkali metal hydroxide to polycarbonate resin (mass of alkali metal hydroxide / mass of polycarbonate resin) is small, the decomposition rate will be slow, the decomposition time will be long, and efficiency will tend to deteriorate. Therefore, the mass ratio is preferably 0.01 or more, more preferably 0.1 or more, and even more preferably 0.5 or more. Furthermore, if the mass ratio is large, the amount of acid required for neutralization after decomposition will increase, and the production efficiency of bisphenol and carbon dioxide will tend to decrease. Therefore, the mass ratio is preferably 50 or less, more preferably 30 or less, and even more preferably 10 or less. Furthermore, the mass ratio may be 8 or less, 5 or less, 3 or less, etc.

[0046] [Alkali metal carbonates] Alkali metal carbonates are formed by the addition of alkali metal ions (M + ) and carbonate ions (CO3 2- ) and is a compound represented by M2CO3 (M represents an alkali metal atom). As the alkali metal carbonate, sodium carbonate or potassium carbonate is preferred.

[0047] If the mass ratio of alkali metal carbonate to polycarbonate resin (mass of alkali metal carbonate / mass of polycarbonate resin) is small, the decomposition rate will be slow, the decomposition time will be long, and efficiency will tend to deteriorate. Therefore, the mass ratio is preferably 0.01 or more, more preferably 0.1 or more, and even more preferably 0.5 or more. Furthermore, if the mass ratio is large, the amount of acid required for neutralization after decomposition will increase, and the production efficiency of bisphenol and carbon dioxide will tend to decrease. Therefore, the mass ratio is preferably 50 or less, more preferably 30 or less, and even more preferably 10 or less. Furthermore, the mass ratio may be 5 or less, 1 or less, 0.5 or less, etc.

[0048] [Alkylamine] 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 of polycarbonate resin to produce isocyanates, so dialkylamines, which are secondary amines, and trialkylamines, which are tertiary amines, are more preferred. Since dialkylamines, which are secondary amines, react with the carbonate bond portions of polycarbonate resins to form tetraalkylureas, trialkylamines, which are tertiary amines, are more preferred.

[0049] The alkylamine preferably has a boiling point of 200°C or less, more preferably 160°C or less. If the boiling point is within this range, it can be removed together with an aromatic monoalcohol such as phenol by reducing pressure and / or heating. If the boiling point is too low, the alkylamine may volatilize during the decomposition reaction, resulting in a decrease in the decomposition rate. Therefore, the boiling point of the alkylamine is preferably 10°C or higher, more preferably 30°C or higher.

[0050] The alkylamine is preferably an alkylamine represented by the general formula (I).

[0051] [ka]

[0052] In formula (I), R A represents an alkyl group having 1 to 3 carbon atoms, and R B ~R C each independently represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. R A is preferably a methyl group, an ethyl group, an n-propyl group, or an isopropyl group, and R B ~R C are each independently preferably a hydrogen atom, a methyl group, an ethyl group, an n-propyl group, or an isopropyl group.

[0053] Specific examples of the alkylamine represented by the general formula (I) include methylamine, ethylamine, propylamine, dimethylamine, diethylamine, trimethylamine, and diethylamine.

[0054] If the mass ratio of alkylamine to polycarbonate resin (mass of alkylamine / mass of polycarbonate resin) is small, the decomposition rate decreases, which leads to a longer decomposition time and a lower efficiency. Therefore, the mass ratio is preferably 0.001 or more, more preferably 0.005 or more, and even more preferably 0.01 or more. Furthermore, if the mass ratio is high, excess alkylamine inhibits the reaction that produces carbon dioxide, so the mass ratio is preferably 50 or less, more preferably 20 or less, and even more preferably 10 or less. Furthermore, the mass ratio may be 5 or less, 1 or less, 0.5 or less, etc.

[0055] [Nitrogen-containing heterocyclic compound] Nitrogen-containing heterocyclic compounds are compounds containing at least one nitrogen atom as an atom forming a heterocycle, and may be monocyclic compounds or polycyclic compounds fused with other aromatic heterocycles or aromatic carbocycles. They may also contain heteroatoms other than nitrogen (sulfur atoms, oxygen atoms, or second nitrogen atoms) in the ring. 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.

[0056] Among these, the nitrogen-containing heterocyclic compound is preferably a pyridine. The pyridine is a substituted or unsubstituted pyridine. Examples of the substituent that can be substituted for the hydrogen atom of pyridine include an alkyl group, an alkoxy group, and a hydroxy group. Preferably, it is one or more selected from the group consisting of unsubstituted pyridine (CHN), methylpyridine, methoxypyridine, and hydroxypyridine, and more preferably, it is unsubstituted pyridine.

[0057] 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 small, the decomposition rate decreases, the decomposition time increases, and the efficiency tends to deteriorate. Therefore, the mass ratio is preferably 0.0001 or more, more preferably 0.0005 or more, and even more preferably 0.001 or more. Furthermore, if the mass ratio is high, the excess nitrogen-containing heterocyclic compound inhibits the reaction that produces carbon dioxide, so the mass ratio is preferably 100 or less, more preferably 50 or less, and even more preferably 10 or less.

[0058] [acid] 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. The acid is preferably any one selected from the group consisting of hydrochloric acid, sulfuric acid, phosphoric acid, and sulfonic acid. The sulfonic acid is an alkylsulfonic acid such as methanesulfonic acid, or an aromatic sulfonic acid such as toluenesulfonic acid.

[0059] If the mass ratio of acid to polycarbonate resin (mass of acid / mass of polycarbonate resin) is small, the decomposition rate decreases, the decomposition time increases, and the efficiency tends to decrease. Therefore, the mass ratio is preferably 0.01 or more, more preferably 0.05 or more, and even more preferably 0.1 or more. Furthermore, if the mass ratio is large, the amount of base required for neutralization tends to increase. Therefore, the mass ratio is preferably 20 or less, more preferably 10 or less, and even more preferably 5 or less.

[0060] (Preparation of reaction solution) By stirring or the like a reaction liquid containing a polycarbonate resin, an aromatic monoalcohol, water, and a catalyst, the polycarbonate resin can be decomposed to produce a bisphenol or a salt thereof. The decomposition reaction of the polycarbonate resin proceeds even if the polycarbonate resin is not completely dissolved by using an aromatic monoalcohol and water in combination. Therefore, the reaction liquid prepared may be a slurry-like reaction liquid (a reaction liquid in which the polycarbonate resin is dispersed). The slurry concentration in the reaction solution (mass of solids in the reaction solution / mass of the reaction solution) is preferably 0.01 or more, more preferably 0.05 or more. It is also preferably 0.5 or less, more preferably 0.3 or less. If the slurry concentration (solids concentration) is too low, the decomposition efficiency decreases, and if the slurry concentration is too high, poor mixing is likely to occur.

[0061] The liquid components in the prepared reaction liquid are mainly composed of aromatic monoalcohol and water, and the total mass of the aromatic monoalcohol and water relative to the mass of all liquid components is 0.8 or more, 0.9 or more, 0.95 or more, etc.

[0062] The preparation of the reaction solution is preferably carried out at 10°C or higher, more preferably 20°C or higher. The preparation of the reaction solution is preferably carried out at 40°C or lower, more preferably 35°C or lower. If the temperature during the preparation of the reaction solution is too low, some types of aromatic monoalcohols may be prone to solidification, leading to poor mixing or making it difficult to achieve uniform mixing. Furthermore, if the temperature during the preparation of the reaction solution is too high, some types of catalysts may be prone to volatilization, making it difficult to prepare the desired concentration or causing the decomposition reaction to run away.

[0063] The order of mixing the polycarbonate resin, aromatic monoalcohol, water, and catalyst is not particularly limited, and for example, the aromatic monoalcohol, water, and catalyst may be sequentially supplied to the polycarbonate resin, or the polycarbonate resin, water, and catalyst may be sequentially supplied to the aromatic monoalcohol. To achieve more uniform mixing, it is preferable to supply the polycarbonate resin after the aromatic monoalcohol and / or water.

[0064] As described above, the decomposition reaction of polycarbonate resin is carried out in the presence of aromatic monoalcohol, water, and a catalyst. However, as long as the object of the present invention is not impaired, polycarbonate resin can also be decomposed in the presence of components other than aromatic monoalcohol, water, and catalyst. In this case, too, it is preferable to disperse the polycarbonate resin in a homogeneous solvent containing aromatic monoalcohol, water, catalyst, and other components and carry out the decomposition reaction. Examples of components that can be coexisted include alkali metal chlorides, bromophenols, and carbon tetrachloride.

[0065] Alkali metal chlorides are alkali metal ions (M + ) and chloride ions (Cl -) and is a compound represented by MCl (M represents an alkali metal atom). Specific examples include sodium chloride and potassium chloride, with sodium chloride being preferred. The amount of alkali metal chloride is not particularly limited, but if it is too much, it may precipitate and cause scaling. 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. If the amount is too small, the effect of adding the alkali metal chloride will be weakened, and when wastewater is used, dilution or the like will be necessary, which may result in the use of a large amount of water and increase the burden on wastewater treatment. Therefore, the mass ratio of alkali metal chloride to water is preferably 0.00001 or more, more preferably 0.0001 or more.

[0066] Bromophenols are compounds in which one hydroxy group and one or two bromine atoms are bonded to carbon atoms forming an aromatic ring. Bromophenols may also have substituents other than hydroxy groups and bromine atoms. Monobromophenols and / or dibromophenols are preferred. The amount of bromophenols is not particularly limited, but if it is too much, 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 the amount is too small, the effect of improving the efficiency of the decomposition reaction of polycarbonate resins is weakened. Therefore, the mass ratio of bromophenols to water is preferably 0.0000001 or more, more preferably 0.000001 or more.

[0067] Although the amount of carbon tetrachloride is not particularly limited, if it is too much, the reaction solution will separate into oil and water, making it impossible to efficiently decompose the polycarbonate resin, so 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 will be weakened, so the mass ratio of carbon tetrachloride to water is preferably 0.0000001 or more, more preferably 0.000001 or more.

[0068] Specifically, when the catalyst contains a nitrogen-containing heterocyclic compound, polycarbonate resins can be decomposed in the presence of an alkali metal chloride (preferably sodium chloride) in addition to an aromatic monoalcohol, water, and the catalyst. The alkali metal chloride acts as a promoter, which is thought to enable more efficient decomposition of polycarbonate resins.

[0069] When the catalyst contains hydrochloric acid, polycarbonate resins can be decomposed in the coexistence of bromophenols in addition to aromatic monoalcohols, water, and the catalyst. It is believed that the bromophenols function as a co-catalyst, enabling more efficient decomposition of polycarbonate resins.

[0070] When the catalyst contains sodium hydroxide, polycarbonate resins can be decomposed in the presence of sodium chloride and / or carbon tetrachloride in addition to aromatic monoalcohol, water, and the catalyst. The presence of sodium chloride or carbon tetrachloride is thought to enable more efficient decomposition of polycarbonate resins.

[0071] The reaction liquid can also be prepared using wastewater discharged during the production of diaryl carbonate, etc. In particular, for the decomposition of a polycarbonate resin in the coexistence of an aromatic monoalcohol, water, a nitrogen-containing heterocyclic compound, and an alkali metal chloride, the decomposition of a polycarbonate resin in the coexistence of an aromatic monoalcohol, water, hydrochloric acid, and a bromophenol, and the decomposition of a polycarbonate resin in the coexistence of an aromatic monoalcohol, water, sodium hydroxide, sodium chloride, and carbon tetrachloride, the use of wastewater discharged from a production plant, etc., as will be described later, makes it possible to easily prepare the reaction liquid and reduce the environmental load.

[0072] (Decomposition reaction) In the presence of aromatic monoalcohol, water, and a catalyst, the carbonate bond of the polycarbonate resin is cleaved, producing bisphenol and carbon dioxide, or a bisphenol salt and a metal carbonate. To prevent the decomposition reaction from proceeding during the preparation of the reaction solution (during the mixing of the polycarbonate resin, aromatic monoalcohol, water, and catalyst), the concentration of the polycarbonate resin and the temperature during the preparation of the reaction solution may be controlled to clearly separate the process of preparing a reaction solution containing the polycarbonate resin, aromatic monoalcohol, water, and catalyst from the process of decomposing the polycarbonate resin in the reaction solution. However, the process of preparing the reaction solution and the process of decomposing the polycarbonate resin do not necessarily have to be clearly separated. The decomposition reaction of the polycarbonate resin may proceed during the preparation of the reaction solution, and a portion of the polycarbonate resin may be decomposed. By partially decomposing the polycarbonate resin during the preparation of the reaction solution, the decomposition reaction can proceed more efficiently.

[0073] The decomposition reaction may be carried out under normal pressure or under increased pressure, but is preferably carried out under normal pressure since the reaction proceeds sufficiently even under normal pressure.

[0074] (Reaction temperature) The reaction mixture may be prepared at the same temperature as when the reaction mixture was prepared until the decomposition reaction is terminated. However, it is preferable to raise the temperature to a predetermined reaction temperature after the reaction mixture is prepared (after mixing the polycarbonate resin, aromatic monoalcohol, water, and catalyst). If the temperature during the preparation of the reaction mixture is too high, the decomposition reaction may run away. Raising the temperature after the preparation of the reaction mixture is preferable because it allows the decomposition reaction to proceed stably.

[0075] The reaction temperature is appropriately selected depending on the type of aromatic monoalcohol, reaction time, etc., but at high temperatures, water in the reaction solution evaporates, and hydrolysis stops. At low temperatures, the aromatic monoalcohol solidifies, solvolysis does not proceed easily, and the hydrolysis reaction rate decreases, resulting in a longer time required for decomposition. For these reasons, the reaction temperature is preferably 40°C or higher, more preferably 50°C or higher, 60°C or higher, 70°C or higher, 75°C or higher, and 80°C or higher in that order. The reaction temperature is also preferably 110°C or lower, more preferably 100°C or lower, and even more preferably 95°C or lower.

[0076] In particular, the decomposition of polycarbonate resin is preferably carried out at a reaction temperature of 40 to 110°C under normal pressure, more preferably at a reaction temperature of 50 to 100°C under normal pressure, and even more preferably at a reaction temperature of 60 to 95°C under normal pressure.

[0077] When the reaction is carried out at the same temperature as when the reaction solution was prepared, the reaction temperature is the average temperature from the time when mixing of the polycarbonate resin, aromatic monoalcohol, water, and catalyst is completed to the time when neutralization or distillation to terminate the decomposition reaction is started. When the reaction is carried out by raising the temperature after the preparation of the reaction solution, the reaction temperature is the average temperature from the time when a predetermined temperature is reached to the time when neutralization or distillation to terminate the decomposition reaction is started.

[0078] (Reaction time) The reaction time is appropriately selected depending on the slurry concentration, reaction temperature, etc., but since a long reaction time tends to decompose the produced bisphenol, it is preferably within 30 hours, more preferably within 25 hours, and even more preferably within 20 hours. Also, since a short reaction time may not allow the decomposition reaction to proceed sufficiently, 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. The reaction time is the time from the completion of mixing the polycarbonate resin, aromatic monoalcohol, water, and catalyst to the start of neutralization and distillation to terminate the decomposition reaction. The end point of the reaction time may be determined by monitoring the decomposition reaction using liquid chromatography or the like.

[0079] (Method for stopping the decomposition reaction of polycarbonate resin) The method for terminating the decomposition reaction of polycarbonate resin is appropriately selected depending on the type of catalyst used. When an alkali metal hydroxide, alkali metal carbonate, or acid is used as the catalyst, the decomposition reaction can be terminated by neutralization or the like. When an alkylamine or a nitrogen-containing heterocyclic compound is used as the catalyst, the decomposition reaction can be terminated by distilling off or neutralizing the alkylamine or nitrogen-containing heterocyclic compound. In the method of removing the alkylamine or nitrogen-containing heterocyclic compound by neutralization with an acid, ammonium salts and the like are generated, which also need to be removed. Therefore, the alkylamine or nitrogen-containing heterocyclic compound is preferably removed by distillation.

[0080] (Bisphenol recovery and purification method) The resulting bisphenol can be recovered and purified by conventional methods. For example, it can be recovered and purified by simple means such as crystallization or column chromatography. Specifically, after the decomposition reaction of the polycarbonate resin, the catalyst and solvent are removed and an organic solvent is mixed. The resulting organic phase is washed with water or saline, and if necessary, neutralized and washed with ammonium chloride water. The washed organic phase is then cooled and crystallized. Examples of organic solvents that can be used include 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, i-propanol, n-butanol, i-butanol, t-butanol, n-pentanol, i-pentanol, n-hexanol, n-heptanol, n-octanol, n-nonanol, n-decanol, n-undecanol, n-dodecanol, ethylene glycol, diethylene glycol, and triethylene glycol.

[0081] Before the crystallization, excess aromatic monoalcohol and organic solvent may be removed by distillation before the crystallization. Furthermore, when bisphenol A is crystallized in the presence of phenol, it forms a co-crystal with phenol. When a polycarbonate resin containing structural units derived from bisphenol A is decomposed using phenol, it is necessary to remove the phenol by distillation before the crystallization to prevent the formation of a co-crystal.

[0082] (Carbon dioxide recovery and purification method) In the method for producing bisphenol of the present invention, the produced carbon dioxide may be recovered and purified. The carbon dioxide can be purified by a conventional method. For example, physical absorption, chemical absorption, cryogenic separation, membrane separation, pressure swing adsorption, etc. can be applied, and an appropriate method can be selected depending on the impurities in the carbon dioxide produced during neutralization.

[0083] The bisphenol production method of the present invention will be described in more detail below, taking as examples bisphenol production methods (A) to (C) for producing bisphenol A from a polycarbonate resin containing a structural unit derived from 2,2-bis(4-hydroxyphenyl)propane (bisphenol A).

[0084] <Bisphenol manufacturing method (A)> The bisphenol production method (A) comprises the steps of: (A1) decomposing a polycarbonate resin containing structural units derived from bisphenol A in a reaction solution containing phenol, water, and an alkali metal hydroxide; (A2) neutralizing the reaction solution after step (A1) to obtain an organic phase in which bisphenol A is dissolved; and (A3) reducing the pressure and / or heating the organic phase obtained in step (A2) and then recovering bisphenol A by crystallization. The bisphenol production method (A) is an example of the bisphenol production method of the present invention in which phenol is used as the aromatic monoalcohol and an alkali metal hydroxide is used as the catalyst.

[0085] 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 of bisphenol and alkali metal carbonates. Note that n in the following reaction formula (2) is 2 to 1000.

[0086] [ka]

[0087] In the method for producing bisphenol (A), in order to produce bisphenol A from an alkali metal salt of bisphenol A and carbon dioxide from an alkali metal carbonate, a step (A2) is carried out in which the reaction solution after step (A1) is neutralized to obtain an organic phase in which bisphenol A is dissolved. Neutralization is carried out by mixing an acid into the reaction solution. Examples of acids that can be used include hydrochloric acid, sulfuric acid, and phosphoric acid. Neutralization by mixing an acid may be carried out so that the pH of the reaction solution is less than 7 or greater than 7, but if the pH is less than 7, the quality of the isolated bisphenol A may be reduced. Therefore, it is preferable to mix the acid so that the reaction solution reaches a pH greater than 7 (for example, pH 7.5 or greater or pH 8.0 or greater) as the end point. On the other hand, if the pH of the reaction solution is too high, it is difficult to produce bisphenol and carbon dioxide, so the acid is mixed so that the pH is 10 or less, and preferably 9.5 or less.

[0088] Furthermore, by leaving the mixture of the reaction liquid and acid to stand, oil-water separation can be achieved into an organic phase (phenol phase) in which the produced bisphenol A is dissolved, and an aqueous phase in which alkali metal hydroxides, etc. (alkali metal hydroxides, acid added for neutralization, and salts produced by neutralization) are dissolved. Therefore, by removing the aqueous phase, alkali metal hydroxides, etc. can be removed.

[0089] An organic solvent such as an aromatic hydrocarbon may be added before or after the acid is added. After the reaction solution is mixed with the acid and organic solvent and neutralized, the reaction solution is separated into oil and water, and the aqueous phase is removed, yielding an organic phase (a phase of phenol and organic solvent) in which bisphenol A is dissolved. Adding an organic solvent facilitates oil-water separation, making it easier to remove the aqueous phase in which alkali metal hydroxides and the like are dissolved.

[0090] In step (A3), the organic phase obtained in step (A2) is reduced in pressure and / or heated, and then bisphenol A is recovered by crystallization. If phenol is present during crystallization, bisphenol A forms co-crystals with phenol and precipitates. Therefore, in step (A3), phenol is removed before crystallization to obtain bisphenol A. Specifically, the organic phase obtained in step (A2) is subjected to reduced pressure and / or heating to distill off liquid components such as phenol. Next, an organic solvent such as an aromatic hydrocarbon is added to prepare a crystallization solution in which bisphenol A is dissolved, and the solution is then cooled to precipitate bisphenol A. The precipitated bisphenol A is recovered by solid-liquid separation.

[0091] When an alkali metal carbonate is used as the catalyst, the process can be carried out in the same manner as in the process (A) for producing bisphenol.

[0092] <Bisphenol manufacturing method (B)> The method for producing bisphenol (B) comprises a step (B1) of decomposing a polycarbonate resin containing a structural unit derived from bisphenol A in a reaction solution containing phenol, water, and an alkylamine, and a step (B2) of reducing the pressure and / or heating the reaction solution after step (B1) and then recovering bisphenol A by crystallization. The method for producing bisphenol (B) is an example of the method for producing bisphenol of the present invention in which phenol is used as the aromatic monoalcohol and an alkylamine is used as the catalyst.

[0093] The main decomposition reaction takes place according to the following reaction formula (3), and the main decomposition products obtained in step (B1) are bisphenol and carbon dioxide. Note that n in the following reaction formula (3) is 2 to 1000.

[0094] [ka]

[0095] In the bisphenol production method (B), the reaction solution after step (B1) is decompressed and / or heated, and then step (B2) is carried out to recover bisphenol A by crystallization. Specifically, the reaction solution after step (B1) is decompressed and / or heated to distill off liquid components such as alkylamines and phenols. Next, an organic solvent such as an aromatic hydrocarbon is added to prepare a crystallization solution in which bisphenol A is dissolved, and this is then cooled to precipitate bisphenol A. The precipitated bisphenol A is recovered by solid-liquid separation.

[0096] When an alkylamine is used as the catalyst, the alkylamine may be removed by a method of neutralizing the reaction mixture by supplying an acid, as in step (A2) of the bisphenol production method (A). In this case, the reaction mixture after the decomposition reaction is neutralized by adding an acid, followed by oil-water separation and removal of the aqueous phase, to obtain an organic phase in which bisphenol A is dissolved. Next, as in step (A3) of the bisphenol production method (A), the resulting organic phase is reduced in pressure and / or heated, and bisphenol A can be recovered by crystallization.

[0097] As described above, methods for removing alkylamine from the decomposition reaction liquid of polycarbonate resin include a method of distilling it off and a method of neutralizing it by supplying an acid. In the method of neutralizing it by supplying an acid, an ammonium salt is generated, which also needs to be removed, so the distillation method is preferred. By using an alkylamine as a catalyst, the alkylamine can be removed together with phenol by reducing pressure and / or heating, and since neutralization is not essential, purification can be simplified.

[0098] When a nitrogen-containing heterocyclic compound is used as the catalyst, the process can be carried out in the same manner as in the process for producing bisphenol (A) and the process for producing bisphenol (B).

[0099] <Bisphenol manufacturing method (C)> The bisphenol production method (C) comprises the steps of: (C1) decomposing a polycarbonate resin containing structural units derived from bisphenol A in a reaction solution containing phenol, water, and an acid; (C2) neutralizing the reaction solution after step (C1) to obtain an organic phase in which bisphenol A is dissolved; and (C3) reducing the pressure and / or heating the organic phase obtained in step (C2) and then recovering bisphenol A by crystallization. The bisphenol production method (C) is an example of the bisphenol production method of the present invention in which phenol is used as the aromatic monoalcohol and an acid is used as the catalyst.

[0100] The main decomposition reaction takes place according to the following reaction formula (4), and the main decomposition products obtained in step (C1) are bisphenol and carbon dioxide. Note that n in the following reaction formula (4) has the same meaning as in general formula (1). Note that n in the following reaction formula (4) is 2 to 1000.

[0101] [ka]

[0102] In the bisphenol production method (C), after step (C1), step (C2) is carried out in which the reaction solution is neutralized to obtain an organic phase in which bisphenol A is dissolved. Neutralization is carried out by mixing a base with the reaction solution. Examples of bases that can be used include sodium carbonate and sodium hydroxide. As in step (A2) of the bisphenol production method (A), neutralization is preferably carried out so that the pH of the reaction solution reaches a point greater than 7. For example, a base is preferably added to achieve a pH of 7.5 or higher or 8.0 or higher. Alternatively, a base is preferably added to achieve a pH of 10 or lower or 9.5 or lower. In step (C2), similarly to step (A2) of the bisphenol production method (A), a mixture of the reaction solution and a base, or a mixture of the reaction solution, a base, and an 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.

[0103] In step (C3), bisphenol A is recovered from the organic phase obtained in step (C2) in which bisphenol A has been dissolved. As in step (A3) of the bisphenol production method (A), the organic phase obtained in step (C2) is reduced in pressure and / or heated, and then bisphenol A can be recovered by crystallization.

[0104] In the bisphenol production methods (A) to (C), phenol is used as the aromatic monoalcohol. However, when an aromatic monoalcohol other than phenol, such as cresol or xylenol, is used as the aromatic monoalcohol, bisphenol A does not form a cocrystal, and therefore removal of the aromatic monoalcohol by reducing pressure and / or heating in steps (A3), (B2), and (C3) is not essential. In this case, bisphenol A can be recovered by cooling the organic phase obtained in step (A2) or step (C2) or the reaction solution after step (B1) to precipitate bisphenol A. The use of cresol or xylenol can simplify the purification of bisphenol A.

[0105] Alternatively, bisphenol A may be recovered as a co-crystal of bisphenol A and phenol. In this case, the phenol is not distilled off, but the organic phase obtained in step (A2) or step (C2) or the reaction liquid after step (B1) is cooled to precipitate and recover a co-crystal of bisphenol A and phenol.

[0106] Furthermore, as described above, the polycarbonate resin used in the method for producing bisphenol of the present invention is not limited to polycarbonate resins 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 carried out appropriately in the same manner as the above-mentioned methods for producing bisphenol (A) to (C).

[0107] <Production of bisphenol using wastewater> In the method for producing bisphenol of the present invention, as described above, wastewater discharged from a diaryl carbonate production plant or the like can be used to prepare the reaction solution. By using wastewater, the wastewater can be used effectively, resulting in a production method with a smaller environmental impact.

[0108] For example, neutralization wastewater discharged from a neutralization treatment facility of a diaryl carbonate manufacturing plant can be used to decompose polycarbonate resin. Diaryl carbonate is generally produced by a method comprising the following steps (a1), (b1), (b2), and (b3), and step (b1) is the neutralization treatment.

[0109] Step (a1): A step of reacting carbonyl chloride with an aromatic monoalcohol in the presence of a nitrogen-containing heterocyclic compound to obtain a reaction solution containing a diaryl carbonate. Step (b1): A step of neutralizing the reaction solution containing the diaryl carbonate obtained in step (a1) with an aqueous alkali metal hydroxide solution, separating the mixture into an oil phase containing the aromatic diaryl and an aqueous phase containing the nitrogen-containing heterocyclic compound and an alkali metal chloride, and then 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)

[0110] In the bisphenol production method of the present invention, the neutralization wastewater (aqueous phase) removed in step (b1) can be used to decompose polycarbonate resin. Since aromatic monoalcohols are contained not only in the oil phase but also in the aqueous phase, the neutralization wastewater discharged in step (b1) is water containing aromatic monoalcohols, nitrogen-containing heterocyclic compounds, and alkali metal chlorides (neutralization salts). Therefore, by mixing polycarbonate resin with the neutralization wastewater discharged in step (b1), a reaction liquid containing polycarbonate resin, aromatic monoalcohols, water, nitrogen-containing heterocyclic compounds, and alkali metal chlorides can be easily prepared.

[0111] In step (a1), the aromatic monoalcohol is the same as the aromatic monoalcohol used in decomposing the polycarbonate resin. It is preferable that the aromatic monoalcohol used in decomposing the polycarbonate resin is the same as the aromatic monoalcohol used in step (a1). In step (a1), the nitrogen-containing heterocyclic compound is the same as the nitrogen-containing heterocyclic compound that can be used in decomposing the polycarbonate resin, and pyridines are preferred.

[0112] The aqueous alkali metal hydroxide solution used in step (b1) is a solution in which an alkali metal hydroxide is dissolved in water. The alkali metal hydroxide is the same as the alkali metal hydroxide that can be used for decomposing polycarbonate resins. Step (b1) is preferably a step in which the reaction solution containing the diaryl carbonate obtained in step (a1) is neutralized with an aqueous sodium hydroxide solution, oil-water separation is performed into an oil phase containing the aromatic diaryl and an aqueous phase containing a nitrogen-containing heterocyclic compound and sodium chloride, and the aqueous phase is then removed as neutralization wastewater. More preferably, step (b1) is a step in which the reaction solution containing the diaryl carbonate obtained in step (a1) is neutralized with an aqueous sodium hydroxide solution, oil-water separation is performed into an oil phase containing the aromatic diaryl and an aqueous phase containing pyridines and sodium chloride, and the aqueous phase is then removed as neutralization wastewater.

[0113] In addition, hydrochloric acid wastewater discharged during recovery of hydrogen chloride, a by-product of producing diaryl carbonate from carbonyl chloride and an aromatic monoalcohol, can be used for decomposing polycarbonate resin. For example, hydrochloric acid wastewater discharged from a hydrogen chloride recovery facility attached to a diaryl carbonate production plant can be used. In general, the production of diaryl carbonate and the recovery of the by-product hydrogen chloride include the following steps (a1), (c1), (c2), and (c3).

[0114] Step (a1): A step of reacting carbonyl chloride with an aromatic monoalcohol in the presence of a nitrogen-containing heterocyclic compound to obtain a reaction solution containing a diaryl carbonate. Step (c1): A step of supplying the hydrogen chloride by-produced in step (a1) to an absorption tower and absorbing it in water or dilute hydrochloric acid to obtain concentrated hydrochloric acid. Step (c2): A step of distilling concentrated hydrochloric acid in a stripper column, recovering hydrogen chloride gas from the top of the column, and recovering hydrochloric acid from the bottom of the column. Step (c3): A step of removing a part of the hydrochloric acid recovered from the bottom of the column to the outside of the system as hydrochloric acid waste water, and circulating the remaining hydrochloric acid to the absorption column of step (c1).

[0115] In the bisphenol production method of the present invention, the hydrochloric acid wastewater removed in step (c3) can be used to decompose polycarbonate resin. The hydrochloric acid wastewater discharged in step (c3) contains bromophenols produced by a side reaction between the aromatic monoalcohol and Cl-Br, which is contained in small amounts in the carbonyl chloride used as a raw material in step (a1). Therefore, by mixing the polycarbonate resin, the aromatic monoalcohol, and the hydrochloric acid wastewater discharged in step (c3), a reaction liquid containing the polycarbonate resin, the aromatic monoalcohol, water, hydrochloric acid, and the bromophenols can be easily prepared.

[0116] In addition, sodium hydroxide wastewater discharged during the detoxification treatment of unliquefied gas generated during the production of carbonyl chloride, a raw material for diaryl carbonate, can be used to decompose polycarbonate resin. For example, sodium hydroxide wastewater discharged from an unliquefied gas removal tower (detoxification treatment facility) installed in a carbonyl chloride production plant can be used. In general, the production of carbonyl chloride and the treatment of unliquefied gas include the following steps (d1), (d2), (d3), and (d4).

[0117] Step (d1): A step of obtaining carbonyl chloride gas from chlorine and carbon monoxide Step (d2): A step of cooling the carbonyl chloride gas obtained in step (d1) to obtain liquefied carbonyl chloride. Step (d3): A step of contacting the circulating aqueous sodium hydroxide solution with the unliquefied gas that was not liquefied in step (d2) to decompose carbonyl chloride in the unliquefied gas, and then discharging the decomposed carbonyl chloride. Step (d4): A step of removing a portion of the circulating aqueous sodium hydroxide solution as sodium hydroxide wastewater.

[0118] In the bisphenol production method of the present invention, the sodium hydroxide wastewater removed in step (d4) can be used to decompose polycarbonate resin. The sodium hydroxide wastewater discharged in step (d3) contains sodium chloride produced by neutralization and carbon tetrachloride as a by-product. Therefore, by mixing polycarbonate resin, aromatic monoalcohol, and the sodium hydroxide wastewater discharged in step (d4), a reaction liquid containing polycarbonate resin, aromatic monoalcohol, water, sodium hydroxide, sodium chloride, and carbon tetrachloride can be easily prepared.

[0119] The methods (R1) to (R3) for producing bisphenol using wastewater will be specifically described below with reference to FIGS.

[0120] <Production method of bisphenol using wastewater (R1)> FIG. 1 is a flow diagram illustrating an example of a method for producing bisphenol by utilizing neutralized wastewater discharged from a diphenyl carbonate production plant.

[0121] (Diphenyl carbonate production) In the diphenyl carbonate production plant 1 shown in Fig. 1, first, a reaction liquid (L10) containing diphenyl carbonate is obtained by reacting carbonyl chloride gas (CDC, G1) with phenol (PL) in the presence of pyridine (PRD) in a DPC reactor 10 (step (a1)). Hydrogen chloride gas (G10), which is a by-product of this reaction, is sent from the top of the DPC reactor 10 to an activated carbon tower (not shown).

[0122] The reaction liquid (L10) containing diphenyl carbonate is sent from the DPC reactor 10 to a dehydrochlorination tower 11 where it is subjected to dehydrochlorination treatment. The hydrogen chloride gas (G12) produced in the dehydrochlorination tower 11 is sent to an activated carbon tower (not shown) along with the hydrogen chloride gas (G10) produced as a by-product in the DPC reactor 10.

[0123] The reaction liquid (L11) after the dehydrochlorination treatment is sent to a mixing tank 12 and then to a neutralization tank 13. In the neutralization tank 13, hydrochloric acid that was not completely removed in the dehydrochlorination tower 11 is neutralized with an aqueous sodium hydroxide solution (L12), and then oil-water separation is carried out. After oil-water separation, the aqueous phase (L14) is discharged as neutralization wastewater, and the obtained oil phase (L13) is sent to a water washing tank 14 (step (b1)). Note that this neutralization wastewater (aqueous phase (L14)) contains water, phenol, pyridine, and sodium chloride.

[0124] In the water washing tank 14, a water washing treatment with water (L15) is carried out (step (b2)). The oil phase (L13) sent to the water washing tank 14 is mixed with the water (L15), and the water phase (L17) is removed, thereby obtaining an oil phase (L16). The water-washed oil phase (L16) is sent successively to a distillation column 15 and a distillation column 16, where it is distilled, and purified diphenyl carbonate (G13) is recovered from the top of the distillation column 16 (step (b3)).

[0125] (Bisphenol production) The aqueous phase (L14, neutralization wastewater) discharged from the neutralization tank 13 is sent to the decomposition tank 100 and mixed with bisphenol A-type polycarbonate resin (PC), where the polycarbonate resin is decomposed. The reaction solution prepared in the decomposition tank 100 only needs to contain at least a portion of the aqueous phase (L14, neutralization wastewater). Therefore, in addition to the aqueous phase (L14, neutralization wastewater), water (HO) or phenol (PL) other than the neutralization wastewater (L14) can also be supplied to the decomposition tank 100 to decompose the polycarbonate resin. A base may also be supplied separately as a catalyst. By supplying water, phenol, and base separately, the ratio of water to phenol and the amount of catalyst can be adjusted appropriately. The additional base used in this case is preferably pyridine, which is used as a catalyst in the production of diphenyl carbonate. The bisphenol A-containing solution (L100) after PC decomposition is sent to equipment for subsequent processes, such as catalyst distillation and neutralization, where bisphenol A is recovered (not shown).

[0126] <Production method of bisphenol using wastewater (R2)> FIG. 2 is a flow diagram illustrating an example of a method for producing bisphenol by utilizing hydrochloric acid wastewater discharged from a recovery plant 2 for hydrogen chloride produced as a by-product in the production of diphenyl carbonate.

[0127] (Chlorine recovery) The hydrogen chloride gas (G10, G12) by-produced in the DPC reactor 10 is sent to an activated carbon tower 20, where organic impurities such as phenol are adsorbed and removed. The hydrogen chloride gas (G20) after treatment with activated carbon is sent to an absorption tower 21. The hydrogen chloride gas (G20) is absorbed in water (L20) or dilute hydrochloric acid (L21, an unsaturated aqueous solution of hydrogen chloride) supplied to the absorption tower 21, discharged as concentrated hydrochloric acid (L23), and stored in a tank 22 (step (c1)). The hydrogen chloride gas (G20) is then sent to a stripper tower 23 where it is distilled, and highly pure hydrogen chloride gas (G21) is distilled from the top of the tower. Dilute hydrochloric acid (L24) is discharged from the bottom of the stripper tower 23 and stored in a tank 24 (step (c2)). Of the dilute hydrochloric acid (L24) stored in tank 24, a certain amount is discharged from tank 24 as hydrochloric acid waste water (L25) to prevent the concentration of impurities, and the remaining dilute hydrochloric acid (L26) is returned to absorption tower 21 (step (c3)). The hydrochloric acid waste water (L25) contains water, hydrogen chloride, and bromophenols (monobromophenol and / or dibromophenol).

[0128] (Bisphenol production) The hydrochloric acid wastewater (L25) discharged from tank 24 is sent to decomposition tank 102 and mixed with bisphenol A-type polycarbonate resin (PC) and phenol (PL), where the polycarbonate resin is decomposed. The reaction solution prepared in decomposition tank 102 may contain at least a portion of hydrochloric acid wastewater (L25). Therefore, in addition to the hydrochloric acid wastewater (L25), water (HO) other than the hydrochloric acid wastewater (L25) may also be supplied to decomposition tank 102 to decompose the polycarbonate resin. An acid may also be supplied separately as a catalyst. Hydrochloric acid is preferred as the additional acid. By supplying water and acid separately, the amount of catalyst can be adjusted appropriately. The solution (L102) containing bisphenol A after PC decomposition is sent to equipment for subsequent processes, such as catalyst distillation and neutralization, where bisphenol A is recovered (not shown).

[0129] <Production method of bisphenol using wastewater (R3)> FIG. 3 is a flow diagram illustrating an example of a method for producing bisphenol by utilizing sodium hydroxide wastewater discharged from a detoxification tower 34 provided in a carbonyl chloride production plant 3.

[0130] (Production of carbonyl chloride and treatment of unliquefied gas) In the carbonyl chloride production plant 3, first, carbon monoxide gas (CO) and chlorine gas (CL2) are supplied to a CDC reactor 30 filled with granular activated carbon (catalyst) to obtain crude carbonyl chloride gas (G30) (step (d1)). The obtained crude carbonyl chloride gas (G30) is sent to a condenser 31, where it is cooled with brine, and the liquefied carbonyl chloride (L30) is stored in a tank 32 (step (d2)). The carbonyl chloride (L30) stored in the tank 32 is evaporated in an evaporator 33 and used as carbonyl chloride gas (G1) in a diphenyl carbonate production plant or the like (not shown).

[0131] The unliquefied gas (G31) that was not liquefied in the condenser 31 is supplied to a detoxification tower 34 in which an aqueous sodium hydroxide solution (L31) is circulated. The unliquefied gas (G31) is brought into contact with the aqueous sodium hydroxide solution (L31) to decompose the carbonyl chloride in the unliquefied gas (G31), and the unliquefied gas (G31) is then discharged into the atmosphere as waste gas (G32) (step (d3)). In addition, in the detoxification tower 34, in order to prevent the concentration of impurities, a portion of the circulating sodium hydroxide (L31) is discharged as sodium hydroxide waste water (L32) (step (d4)). The sodium hydroxide waste water (L32) contains water, sodium hydroxide, sodium chloride, and carbon tetrachloride.

[0132] (Bisphenol production) The sodium hydroxide wastewater (L32) discharged from the detoxification tower 34 is sent to the decomposition tank 103 and mixed with bisphenol A-type polycarbonate resin (PC) and phenol (PL), where the polycarbonate resin is decomposed. The reaction solution prepared in the decomposition tank 103 may contain at least a portion of the sodium hydroxide wastewater (L32). Therefore, in addition to the sodium hydroxide wastewater (L32), water (HO) other than the sodium hydroxide wastewater (L32) may also be separately supplied to the decomposition tank 103 to decompose the polycarbonate resin. A base may also be separately supplied as a catalyst. Sodium hydroxide is preferred as the additional base. By allowing water and catalyst to be separately supplied, the amount of catalyst can be appropriately adjusted. The bisphenol A-containing solution (L103) obtained after PC decomposition is sent to equipment for subsequent processes, such as catalyst distillation and neutralization, where bisphenol A is recovered (not shown).

[0133] <Uses of bisphenol> The bisphenol obtained by the bisphenol production method of the present invention (hereinafter, sometimes referred to as "recycled bisphenol") can be used as a constituent, curing agent, additive, or precursor thereof for various thermoplastic resins such as polyether resins, polyester resins, polyarylate 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 a variety of applications including optical materials, recording materials, insulating materials, transparent materials, electronic materials, adhesive materials, and heat-resistant materials. It is also useful as a color developer or additive for thermal recording materials, etc., such as a color-fading inhibitor, a disinfectant, and an antibacterial and antifungal agent.

[0134] Among these, it is preferably used as a raw material (monomer) for thermoplastic resins and thermosetting resins, because it can impart good mechanical properties, and more preferably as a raw material for polycarbonate resins and epoxy resins. It is also preferably used as a color developer, and more preferably used in combination with a leuco dye or a discoloration temperature adjuster.

[0135] <Method of producing carbon dioxide> 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") in which carbon dioxide produced by the method for producing bisphenol of the present invention is recovered. According to the method for producing carbon dioxide of the present invention, carbon dioxide can be obtained by efficiently decomposing polycarbonate resin under mild conditions with little environmental impact. As described above, in the method for producing bisphenol of the present invention, carbon dioxide is produced by the decomposition reaction of polycarbonate resin and / or neutralization after the decomposition reaction. This carbon dioxide can be recovered and used as a raw material for carbonate 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.

[0136] Specifically, when the catalyst used for decomposing a polycarbonate resin is a base, the method for producing carbon dioxide of the present invention can include a step of decomposing a polycarbonate resin in the presence of an aromatic monoalcohol, water, and a base (catalyst), and a step of recovering the carbon dioxide produced by the decomposition of the polycarbonate resin.

[0137] Furthermore, when the catalyst used for decomposing the polycarbonate resin is a base, carbon dioxide is also generated during neutralization after the decomposition reaction. Therefore, 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 monoalcohol, water, and a base (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.

[0138] When the catalyst used for decomposing the polycarbonate resin is an acid, the method for producing carbon dioxide of the present invention can include a step of decomposing the polycarbonate resin in the presence of an aromatic monoalcohol, water, and an acid (catalyst), and a step of recovering the carbon dioxide produced by the decomposition of the polycarbonate resin.

[0139] Carbon dioxide recovery can be carried out by a conventional method as described above, and can be appropriately selected depending on the amount of other impurities. For example, physical absorption, chemical absorption, cryogenic separation, membrane separation, pressure swing adsorption, etc. can be applied.

[0140] <Method of producing carbonate diester> The present invention relates to a method for producing a carbonate diester (hereinafter, sometimes referred to as the "method for producing a carbonate diester of the present invention"), in which a carbonate diester is produced using carbon dioxide obtained by the method for producing carbon dioxide of the present invention (hereinafter, sometimes referred to as "regenerated carbon dioxide").

[0141] The method for producing a carbonate diester of the present invention can utilize known methods for producing a carbonate diester using carbon dioxide as a raw material. Furthermore, as long as recycled carbon dioxide is used for at least a portion of the raw carbon dioxide, there are no particular limitations on the content of recycled carbon dioxide in the carbon dioxide. For example, the content of recycled carbon dioxide in the carbon dioxide is preferably 0.1% by volume or more, more preferably 0.5% by volume or more.

[0142] The method for producing a carbonate diester of the present invention can produce dialkyl carbonates such as dimethyl carbonate, diaryl carbonates such as diphenyl carbonate, etc. The carbonate diester obtained by the method for producing a carbonate diester of the present invention can be used as a raw material for polycarbonate resins, an electrolytic solution, etc.

[0143] For example, the method for producing a dialkyl carbonate of the present invention can be the method for producing a dialkyl carbonate described in (M1) below, or the method for producing a diaryl carbonate described in (M2) or (M3) below. (M1) A method for obtaining dialkyl carbonate by reacting carbon dioxide with an aliphatic monoalcohol (M2) A method of reacting carbon dioxide with an aliphatic monoalcohol to obtain a dialkyl carbonate, and then reacting the obtained dialkyl carbonate with an aromatic monoalcohol to obtain a diaryl carbonate. (M3) A method of obtaining carbon monoxide from carbon dioxide and coke, reacting the obtained carbon monoxide with chlorine to obtain carbonyl chloride, and reacting the obtained carbonyl chloride with an aromatic monoalcohol to obtain diaryl carbonate.

[0144] Examples of aliphatic monoalcohols include alcohols having 1 to 10 carbon atoms. Alcohols having 1 to 6 carbon atoms such as methanol, ethanol, propanol, isopropanol, butanol, pentanol, and hexanol are preferred, and methanol or butanol is more preferred.

[0145] The aromatic monoalcohol may be the same as the aromatic monoalcohol used in the method for producing bisphenol of the present invention, and is preferably phenol.

[0146] Each reaction may be carried out in the presence of a known catalyst. Carbon dioxide may be reacted with an aliphatic monoalcohol in the presence of a catalyst, and examples of the catalyst include known catalysts such as cerium oxide. Examples of the catalyst used in the reaction of a dialkyl carbonate with an aromatic monoalcohol include organic titanium catalysts such as tetraphenoxytitanium.

[0147] Among these, as in the above (M1) or (M2), the method for producing a carbonate diester of the present invention is preferably a method including a step of reacting carbon dioxide containing carbon dioxide obtained by the method for producing carbon dioxide of the present invention with an aliphatic monoalcohol.

[0148] <Manufacturing method for recycled polycarbonate resin> The method for producing recycled polycarbonate resin of the present invention is a method for producing recycled polycarbonate resin using a bisphenol raw material containing bisphenol (recycled bisphenol) obtained by the method for producing bisphenol of the present invention, and / or a carbonate diester raw material containing a carbonate diester (hereinafter sometimes referred to as "recycled carbonate diester") obtained by the method for producing carbonate diester of the present invention.

[0149] Hereinafter, the method for producing recycled polycarbonate resin using a bisphenol raw material containing recycled bisphenol will be described as the "first method for producing recycled polycarbonate resin," and the method for producing recycled polycarbonate resin using a carbonate diester raw material containing recycled carbonate diester will be described as the "second method for producing recycled polycarbonate resin." Furthermore, the "first method for producing recycled polycarbonate resin" and the "second method for producing recycled polycarbonate resin" will be collectively referred to as the "method for producing recycled polycarbonate resin of the present invention."

[0150] (First method for producing recycled polycarbonate resin) The first method for producing recycled polycarbonate resin is a method for producing recycled polycarbonate resin using a bisphenol raw material containing bisphenol (recycled bisphenol) obtained by the bisphenol production method of the present invention. The first method for producing recycled polycarbonate resin utilizes a chemical recycling method in which polycarbonate resin is produced using recycled bisphenol as a raw material, which is obtained by decomposing polycarbonate resin contained in waste plastics, etc., into the bisphenol monomer.

[0151] The recycled polycarbonate resin produced by the first recycled polycarbonate resin production method can be produced by a known method for producing polycarbonate resin using bisphenol as a raw material. For example, it can be obtained by polymerizing a bisphenol raw material containing recycled bisphenol (bisphenol obtained by decomposing polycarbonate resin using the bisphenol production method of the present invention) with a carbonate diester raw material. The polymerization can be carried out by appropriately selecting a known method.

[0152] For example, recycled polycarbonate resin can be produced by a method in which a bisphenol raw material containing recycled bisphenol is subjected to an ester exchange reaction with a carbonate diester raw material such as diphenyl carbonate in the presence of an alkali metal compound and / or an alkaline earth metal compound.

[0153] The recycled bisphenol may be used as the entire bisphenol raw material, or may be mixed with a non-recycled ordinary 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 more, 1% by mass or more, 10% by mass or more, 20% by mass or more, 30% by mass or more, 40% by mass or more, 50% by mass or more, 70% by mass or more, 80% by mass or more, or 90% by mass or more. Since a higher proportion of recycled bisphenol is more environmentally friendly, from the viewpoint of environmental consideration, a higher amount of recycled bisphenol relative to the bisphenol raw material is preferable.

[0154] The carbonate diester raw material may contain a recycled carbonate diester, or may contain only a general carbonate diester without containing a recycled carbonate diester.

[0155] The above transesterification reaction can be carried out by appropriately selecting a known method, but an example of a method using diphenyl carbonate as the carbonate diester raw material will be described below.

[0156] In the first method for producing recycled polycarbonate resin, diphenyl carbonate is preferably used in excess relative to the bisphenol raw material. A large amount of diphenyl carbonate is preferred relative to the bisphenol raw material, as this reduces the number of terminal hydroxyl groups in the produced recycled polycarbonate resin and improves the thermal stability of the polymer. A small amount is preferred relative to the bisphenol raw material, as this increases the transesterification rate and facilitates the production of recycled polycarbonate resin with the desired molecular weight. For these reasons, the amount of diphenyl carbonate used relative to 1 mole of 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.

[0157] As a method for supplying the raw materials, the bisphenol raw material and diphenyl carbonate can be supplied in solid form, but it is preferable to melt one or both of them and supply them in a liquid state.

[0158] When producing recycled polycarbonate resin by the transesterification reaction of diphenyl carbonate with a bisphenol raw material, a transesterification catalyst is usually used. The transesterification catalyst is preferably an alkali metal compound and / or an alkaline earth metal compound. These may be used alone or in any combination and ratio of two or more. For practical purposes, it is desirable to use an alkali metal compound.

[0159] The amount of catalyst used per mole of 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.

[0160] When the amount of catalyst used is within the above range, it is easy to obtain the polymerization activity required to produce a recycled polycarbonate resin of the desired molecular weight, and it is also easy to obtain a polycarbonate resin that has excellent polymer color, does not undergo excessive polymer branching, and has excellent fluidity during molding. To produce recycled polycarbonate resin by the above method, it is preferable to continuously feed both of the above raw materials into a raw material mixing tank, and then continuously feed the resulting mixture and the transesterification catalyst into a polymerization tank.

[0161] In the production of recycled polycarbonate resin by the transesterification method, the two raw materials are usually supplied to a raw material mixing tank, stirred uniformly, and then supplied to a polymerization tank where a catalyst is added to produce a polymer.

[0162] (Second method for producing recycled polycarbonate resin) The second method for producing recycled polycarbonate resin is a method for producing recycled polycarbonate resin using a carbonate diester raw material containing a carbonate diester (recycled carbonate diester) obtained by the method for producing a carbonate diester of the present invention. The second method for producing recycled polycarbonate resin can be carried out by appropriately selecting a known polycarbonate resin polymerization method, except for using a carbonate diester raw material containing a recycled carbonate diester. For example, a recycled polycarbonate resin can be produced by reacting a bisphenol raw material with a carbonate diester raw material containing a recycled carbonate diester. The ratio of the bisphenol raw material to the carbonate diester raw material, the catalyst used, and the like are the same as those in the method for producing recycled polycarbonate resin in the first method, except for using a carbonate diester raw material containing a recycled carbonate diester.

[0163] The recycled carbonate diester may be used as the entire carbonate diester raw material, or may be mixed with a general carbonate diester that is not a recycled carbonate diester and used as part of the carbonate diester raw material. The amount of recycled carbonate diester relative to the carbonate diester raw material is not particularly limited, and may be any amount, such as 0.1% by mass or more, 1% by mass or more, 10% by mass or more, 20% by mass or more, 30% by mass or more, 40% by mass or more, 50% by mass or more, 70% by mass or more, 80% by mass or more, or 90% by mass or more. From the standpoint of environmental consideration, a large amount of recycled carbonate diester relative to the carbonate diester raw material is preferable.

[0164] The diester carbonate raw material in the second method for producing recycled polycarbonate resin is preferably a diaryl carbonate raw material containing a diaryl carbonate obtained by the method for producing a diester carbonate of the present invention, and more preferably a diphenyl carbonate raw material containing a diphenyl carbonate obtained by the method for producing a diester carbonate of the present invention.

[0165] Furthermore, when a carbonate diester raw material containing a recycled carbonate diester is used, the bisphenol raw material may contain recycled bisphenol, or may contain only ordinary bisphenol and not contain recycled bisphenol.

[0166] (Recycled polycarbonate resin and its composition) The recycled polycarbonate resin obtained by the method for producing recycled polycarbonate resin of the present invention may be used as is, or may be used as a recycled polycarbonate resin composition containing virgin polycarbonate resin and recycled polycarbonate resin. The recycled polycarbonate resin composition can be obtained by appropriately selecting a known kneading method or the like to mix virgin polycarbonate resin and recycled polycarbonate resin. When preparing a recycled polycarbonate resin composition containing virgin polycarbonate resin and recycled polycarbonate resin, there is no particular limitation on the amount of recycled polycarbonate resin, but the higher the proportion of recycled polycarbonate resin, the more environmentally friendly it is. Therefore, from the perspective of environmental consideration, the amount of recycled polycarbonate resin relative to the recycled polycarbonate resin composition is preferably 50% by mass or more, more preferably 70% by mass or more, 80% by mass or more, and 90% by mass or more. The resulting recycled polycarbonate resin or composition can be molded into various molded articles such as optical members and optical recording media, in the same manner as virgin polycarbonate resin.

[0167] <Epoxy resin manufacturing method> The present invention relates to a method for producing an epoxy resin using the bisphenol obtained by the method for producing a bisphenol of the present invention. The obtained epoxy resin may be further reacted with a polyhydric hydroxy compound raw material to produce an epoxy resin. Thus, the epoxy resin production method 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 epoxy resin production method of the present invention is not particularly limited, and known epoxy resin production methods can be used, except that recycled bisphenol (bisphenol obtained by the bisphenol production method of the present invention) and / or an epoxy resin produced using recycled bisphenol are used as raw materials. For example, recycled bisphenol can be used as at least a portion of the polyvalent hydroxy compound raw material when producing the epoxy resin using a one-stage method, oxidation method, or two-stage method, as described below. The obtained epoxy resin can also be used as at least a portion of the epoxy resin raw material when producing the epoxy resin using a two-stage method.

[0168] The term "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 "recycled epoxy resin"). "Polyhydric hydroxy compound" is a general term for divalent or higher phenolic compounds and divalent or higher alcohol compounds, and "polyhydric hydroxy compound raw material" refers to a polyhydric hydroxy compound used as a raw material for recycled epoxy resin.

[0169] The epoxy resin of the present invention can be produced by a one-stage method, an oxidation method, a two-stage method, or the like. The one-step method for producing an epoxy resin is a method in which recycled bisphenol (bisphenol obtained by the method for producing bisphenol of the present invention) is reacted with epihalohydrin to obtain an epoxy resin. The oxidation method for producing epoxy resin involves allylation of recycled bisphenol with an allyl halide (allyl chloride, allyl bromide, etc.), followed by oxidation to obtain epoxy resin. The two-stage method for producing an epoxy resin is a method in which an epoxy resin raw material is reacted with a polyhydroxy compound raw material, and recycled bisphenol and / or an epoxy resin produced using recycled bisphenol are used as the raw material.

[0170] Hereinafter, methods for producing epoxy resins using the one-stage method, the oxidation method, and the two-stage method will be described.

[0171] (One-stage method for producing epoxy resin) The method for producing an epoxy resin by the one-step method is not particularly limited as long as it is a known production method, but will be described in detail below.

[0172] The one-stage method for producing an epoxy resin may involve using recycled bisphenol in combination with a polyhydric hydroxy compound other than recycled bisphenol (hereinafter, sometimes referred to as "another polyhydric hydroxy compound"). That is, the one-stage method for producing an epoxy resin involves reacting a polyhydric hydroxy compound raw material with epihalohydrin to obtain an epoxy resin, and at least a portion of the polyhydric hydroxy compound raw material can be recycled bisphenol.

[0173] The content of recycled bisphenol in the polyhydroxy compound raw material is not particularly limited, but since a high content of recycled bisphenol is environmentally friendly, it is preferably 1 to 100 mass %, more preferably 10 to 100 mass %.

[0174] Here, "other polyhydric hydroxy compounds" is a general term for divalent or higher phenol compounds and divalent or higher alcohol compounds, excluding recycled bisphenols. In the one-stage method for producing epoxy resins, the "raw polyhydric hydroxy compound" refers to all polyhydric hydroxy compounds, including recycled bisphenols and other polyhydric hydroxy compounds used as needed.

[0175] Other polyhydric hydroxy compounds include various polyhydric phenols such as 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 resin, cresol novolac resin, phenol aralkyl resin, biphenyl aralkyl resin, naphthol aralkyl resin, terpene phenol resin, dicyclopentadiene phenol resin, bisphenol A novolac resin, naphthol novolac resin, brominated bisphenol A, brominated phenol novolac resin, and various phenols and benzaldehyde, hydroxybenzaldehyde, and the like. Examples of the polyhydric phenol resin include polyhydric phenol resins obtained by a condensation reaction between various aldehydes such as benzoxaldehyde, crotonaldehyde, and glyoxal; polyhydric phenol resins obtained by a condensation reaction between xylene resin and phenols; various phenol resins such as co-condensation resins of heavy oils or pitches with phenols and formaldehydes; 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; and polyalkylene ether glycols such as polyethylene ether glycol, polyoxytrimethylene ether glycol, and polypropylene ether glycol.

[0176] In the reaction, the polyhydric hydroxy compound raw material is dissolved in epihalohydrin to form a homogeneous solution. As the epihalohydrin, epichlorohydrin or epibromohydrin is usually used, but epichlorohydrin is preferred in the present invention.

[0177] The amount of epihalohydrin used is preferably an amount corresponding to typically 1.0 to 14.0 equivalents, particularly 2.0 to 10.0 equivalents, per equivalent of hydroxyl groups in the polyhydric hydroxy compound raw material (total polyhydric hydroxy compounds). When the amount of epihalohydrin is equal to or greater than the lower limit, it is easy to control the polymerization reaction, and the resulting epoxy resin can have an appropriate epoxy equivalent, which is preferred. On the other hand, when the amount of epihalohydrin is equal to or less than the upper limit, production efficiency tends to be improved, which is preferred.

[0178] Next, while stirring the solution, an alkali metal hydroxide is added as a solid or in aqueous solution in an amount corresponding to typically 0.1 to 3.0 equivalents, preferably 0.8 to 2.0 equivalents, per equivalent of hydroxyl groups in the polyhydric hydroxy compound raw material, and the reaction is allowed to proceed. Adding an alkali metal hydroxide in an amount equal to or greater than the lower limit described above is preferred because it makes it difficult for unreacted hydroxyl groups to react with the resulting epoxy resin, making it easier to control the polymerization reaction. Adding an alkali metal hydroxide in an amount equal to or less than the upper limit described above is also preferred because it makes it difficult for impurities to be generated by side reactions. The alkali metal hydroxide used here typically includes sodium hydroxide or potassium hydroxide.

[0179] This 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 equal to or higher than the lower limit is preferred because the reaction is easily progressed and easily controlled. On the other hand, a reaction temperature equal to or lower than the upper limit is preferred because side reactions are less likely to proceed, and it is particularly easy to reduce the amount of polymer.

[0180] This reaction is also carried out while dehydrating, if necessary, by azeotroping the reaction solution while maintaining a predetermined temperature, cooling the volatilized vapor, separating the resulting condensate into oil and water, and returning the dehydrated oil to the reaction system. To prevent a rapid reaction, the alkali metal hydroxide is added intermittently or continuously in small amounts over a period of preferably 0.1 to 24 hours, more preferably 0.5 to 10 hours. Adding the alkali metal hydroxide for a period of time equal to or greater than the above-mentioned lower limit is preferred because it prevents the reaction from proceeding too quickly and makes it easier to control the reaction temperature. Adding the alkali metal hydroxide for a period of time equal to or less than the above-mentioned upper limit is preferred because it makes it easier to reduce the amount of polymer.

[0181] After the reaction is completed, the insoluble by-product salts are removed by filtration or by washing with water, and then the unreacted epihalohydrin can be removed by heating and / or distillation under reduced pressure.

[0182] In addition, in this reaction, a catalyst such as a quaternary ammonium salt such as tetramethylammonium chloride or tetraethylammonium bromide, a tertiary amine such as benzyldimethylamine or 2,4,6-tris(dimethylaminomethyl)phenol, an imidazole such as 2-ethyl-4-methylimidazole or 2-phenylimidazole, a phosphonium salt such as ethyltriphenylphosphonium iodide, or a phosphine such as triphenylphosphine may be used.

[0183] Furthermore, in this reaction, an inert organic solvent may be used, 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.

[0184] [Production of epoxy resin with reduced total chlorine content] 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 it with an alkali.

[0185] The reaction with the alkali may be carried out using an organic solvent for dissolving the epoxy resin. The organic solvent used in the reaction is not particularly limited, but it is preferable to use a ketone-based organic solvent in terms of production efficiency, handling, workability, etc. Furthermore, an aprotic polar solvent may be used in order to further reduce the amount of hydrolyzable chlorine.

[0186] Examples of ketone-based organic solvents include ketone-based solvents such as methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone. Methyl isobutyl ketone is particularly preferred because of its effectiveness and ease of post-treatment. These solvents may be used alone or in combination of two or more.

[0187] Examples of aprotic polar solvents include dimethyl sulfoxide, diethyl sulfoxide, dimethyl sulfone, sulfolane, dimethylformamide, dimethylacetamide, and hexamethylphosphoramide. These may be used alone or in combination of two or more. Among these aprotic polar solvents, dimethyl sulfoxide is preferred because it is easily available and has excellent effects.

[0188] The amount of the solvent used is such that the concentration of the epoxy resin in the liquid to be subjected to the alkali treatment is usually 1 to 95% by mass, and preferably 5 to 80% by mass.

[0189] As the alkali, a solid or solution of an alkali metal hydroxide can be used. Examples of the alkali metal hydroxide include potassium hydroxide and sodium hydroxide, and sodium hydroxide is preferred. The alkali metal hydroxide may also be dissolved in an organic solvent or water. Preferably, the alkali metal hydroxide is used as a solution in which it is dissolved in a water solvent or an organic solvent.

[0190] The amount of alkali metal hydroxide used is preferably 0.01 to 20.0 parts by mass or less, and more preferably 0.10 to 10.0 parts by mass, relative to 100 parts by mass of the epoxy resin, calculated as the solid content of the alkali metal hydroxide. If the amount of alkali metal hydroxide used is less than the lower limit, the effect of reducing the total chlorine content is low, and if it is more than the upper limit, a large amount of polymer is produced, resulting in a low yield.

[0191] 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. After the reaction, excess alkali metal hydroxide and secondary salts can be removed by washing with water or the like, and the organic solvent can be further removed by heating and / or distillation under reduced pressure and / or steam distillation.

[0192] (Oxidation method for producing epoxy resin) The method for producing an epoxy resin by oxidation is not particularly limited as long as it is a known production method, and can be carried out according to, for example, the methods described in JP-A-2011-225711, JP-A-2012-092247, JP-A-2012-111858, etc.

[0193] In the oxidation method for producing an epoxy resin, similar to the one-stage method, a polyhydric hydroxy compound other than the recycled bisphenol may be used in combination with the recycled bisphenol. That is, the oxidation method for producing an epoxy resin is a method in which a raw polyhydric hydroxy compound is allylated with an allyl halide, followed by an oxidation reaction to obtain an epoxy resin, and at least a portion of the raw polyhydric hydroxy compound is recycled bisphenol.

[0194] In the oxidation method for producing an epoxy resin, the "raw polyhydroxy compound" refers to all polyhydroxy compounds, including recycled bisphenols and other polyhydroxy compounds used as needed. Examples of the other polyhydroxy compounds include those similar to those used in the one-stage method. The content of recycled bisphenols in the raw polyhydroxy compound is not particularly limited, but a high content of recycled bisphenols is environmentally friendly, so a content of 1 to 100% by mass is preferred, and 10 to 100% by mass is more preferred.

[0195] (Two-stage method for producing epoxy resin) The method for producing an epoxy resin by the two-stage method is not particularly limited as long as it is a known production method, but will be described in detail below.

[0196] The two-stage method for producing an epoxy resin includes a step of reacting an epoxy resin raw material with a polyhydric hydroxy compound raw material, and at least a portion of the epoxy resin raw material is an epoxy resin produced using recycled bisphenol, and / or at least a portion of the polyhydric hydroxy compound raw material is recycled bisphenol.

[0197] That is, the two-stage method for producing an epoxy resin is any one of the following methods (i) to (iii).

[0198] Method (i): A method of reacting an epoxy resin other than an epoxy resin produced using recycled bisphenol with a polyhydroxy compound raw material containing recycled bisphenol.

[0199] In method (i), the epoxy resin raw material is an epoxy resin other than the epoxy resin produced using recycled bisphenol, and the polyhydroxy compound raw material is all polyhydroxy compounds including recycled bisphenol and other polyhydroxy compounds used as needed.

[0200] Method (ii): A method of reacting an epoxy resin raw material containing an epoxy resin produced using recycled bisphenol with a polyhydroxy compound raw material containing recycled bisphenol.

[0201] In method (ii), the epoxy resin raw material is the total epoxy resin, which is a combination of the epoxy resin produced using recycled bisphenol and other epoxy resins used as needed, and the polyhydroxy compound raw material is the total polyhydroxy compound, which is a combination of the recycled bisphenol and other polyhydroxy compounds used as needed.

[0202] Method (iii): A method of reacting an epoxy resin raw material containing an epoxy resin produced using recycled bisphenol with a polyhydroxy compound other than recycled bisphenol.

[0203] In method (iii), the epoxy resin raw material is a total epoxy resin that combines the epoxy resin produced using recycled bisphenol with other epoxy resins that are used as needed, and the polyhydroxy compound raw material is a polyhydroxy compound other than recycled bisphenol.

[0204] The epoxy resins produced using recycled bisphenols used in methods (ii) and (iii) can be obtained by a one-step method for producing epoxy resins or an oxidation method for producing epoxy resins. Alternatively, the epoxy resins obtained by method (i) may be used. The epoxy resins other than the epoxy resins produced using recycled bisphenols are the same as the other epoxy resins described later in the method for producing a cured epoxy resin, and the other polyhydroxy compounds are the same as those used in the one-step method.

[0205] In the methods (i) and (ii), the content of recycled bisphenol in the polyhydroxy compound containing recycled bisphenol is not particularly limited, but a high content of recycled bisphenol is environmentally friendly, so it is preferably 1 to 100 mass%, more preferably 10 to 100 mass%. In 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, but a high content of the epoxy resin produced using recycled bisphenol is environmentally friendly, so the content is preferably 1 to 100 mass%, more preferably 10 to 100 mass%.

[0206] In the two-stage reaction, the amounts of the epoxy resin raw material and the polyvalent hydroxy compound raw material used are preferably such that the equivalent ratio (epoxy group equivalent):(hydroxyl group equivalent) is 1:0.1-2.0, more preferably 1:0.2-1.2. When this equivalent ratio is within the above range, it is easy to promote high molecular weight and more epoxy group terminals can be left, which is preferable.

[0207] A catalyst may be used in the two-stage reaction. Any compound with catalytic activity that promotes the reaction between an epoxy group and a phenolic hydroxyl group or an alcoholic hydroxyl group may be used. Examples of the catalyst include alkali metal compounds, organic phosphorus compounds, tertiary amines, quaternary ammonium salts, cyclic amines, and imidazoles. Among these, quaternary ammonium salts are preferred. The catalyst may be used alone or in combination of two or more. The amount of catalyst used is typically 0.001 to 10% by mass based on the epoxy resin raw material.

[0208] A solvent may be used in the two-stage reaction, and any solvent capable of dissolving the epoxy resin raw material may be used. Examples include aromatic solvents, ketone solvents, amide solvents, and glycol ether solvents. A single solvent may be used, or two or more solvents may be used in combination. The resin concentration in the solvent is preferably 10 to 95% by mass, more preferably 20 to 80% by mass. If a highly viscous product is produced during the reaction, the reaction can be continued by adding additional solvent. After completion of the reaction, the solvent can be removed or further added as necessary.

[0209] 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, the resulting epoxy resin may deteriorate. If the reaction temperature is below the lower limit, the reaction may not proceed sufficiently. The reaction time is usually 0.1 to 24 hours, preferably 0.5 to 12 hours.

[0210] <Method of manufacturing a cured epoxy resin product> The present invention relates to a method for producing a cured epoxy resin product, which comprises curing an epoxy resin composition containing an epoxy resin obtained by the method for producing an epoxy resin of the present invention and a curing agent to obtain a cured epoxy resin product. In the method for producing a cured epoxy resin product of the present invention, the epoxy resin obtained by the method for producing an epoxy resin of the present invention described above and a curing agent are mixed to obtain a composition containing the epoxy resin and the curing agent (hereinafter, sometimes referred to as an "epoxy resin composition"), and then the epoxy resin composition is cured to obtain a cured epoxy resin product.

[0211] Furthermore, if necessary, the epoxy resin composition may appropriately contain other epoxy resins (hereinafter simply referred to as "other epoxy resins") other than the epoxy resin obtained by the epoxy resin production method of the present invention, curing agents, curing accelerators, inorganic fillers, coupling agents, etc.

[0212] The content of recycled epoxy resin in the epoxy resin composition is not particularly limited. Because a high content of recycled epoxy resin is environmentally friendly, the recycled epoxy resin is preferably 40 parts by mass or more, more preferably 60 parts by mass or more, per 100 parts by mass of all epoxy resin components in the recycled epoxy resin composition. When other epoxy resins are included, the recycled epoxy resin can be 40 to 99 parts by mass or 60 to 99 parts by mass, per 100 parts by mass of all epoxy resin components in the epoxy resin composition. The term "total epoxy resin components" refers to the total amount of all epoxy resins contained in the epoxy resin composition, including the recycled epoxy resin and other epoxy resins used as needed.

[0213] (hardening agent) In the present invention, a curing agent refers to a substance that contributes to the crosslinking reaction and / or chain extension reaction between epoxy groups of an epoxy resin. In the present invention, even substances that are usually called "curing accelerators" are considered to be curing agents as long as they contribute to the crosslinking reaction and / or chain extension reaction between epoxy groups of an epoxy resin.

[0214] In the epoxy resin composition, the content of the curing agent 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.

[0215] The curing agent is not particularly limited, and any commonly known epoxy resin curing agent can be used. Examples include phenolic curing agents, amine curing agents such as aliphatic amines, polyetheramines, alicyclic amines, and aromatic amines, acid anhydride curing agents, amide curing agents, tertiary amines, and imidazoles. One curing agent may be used alone, or two or more may be used in combination. When two or more curing agents are used in combination, they may be mixed in advance to prepare a mixed curing agent before use, or when mixing the components of the epoxy resin obtained by the epoxy resin production method of the present invention and other epoxy resins, each component of the curing agent may be added separately and mixed simultaneously.

[0216] [Phenol-based hardener] 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 phenol resin, dicyclopentadiene phenol resin, bisphenol A novolac resin, trisphenolmethane type resin, naphthol novolac resin, brominated bisphenol These include various polyhydric phenols such as phenol A and brominated phenol novolac resins; polyhydric phenol resins obtained by the condensation reaction of various phenols with various aldehydes such as benzaldehyde, hydroxybenzaldehyde, crotonaldehyde, and glyoxal; polyhydric phenol resins obtained by the condensation reaction of xylene resin and phenols; co-condensation resins of heavy oil or pitch with phenols and formaldehydes; and various phenolic resins such as phenol-benzaldehyde-xylylene dimethoxide polycondensates, phenol-benzaldehyde-xylylene dihalide polycondensates, phenol-benzaldehyde-4,4'-dimethoxide biphenyl polycondensates, and phenol-benzaldehyde-4,4'-dihalide biphenyl polycondensates.

[0217] These phenolic curing agents may be used alone or in any combination of two or more in any blending ratio.

[0218] The amount of the phenolic curing agent added is preferably 0.1 to 1000 parts by mass, and more preferably 500 parts by mass or less, per 100 parts by mass of all epoxy resin components in the epoxy resin composition.

[0219] [Amine-based curing agent] Examples of amine-based curing agents (excluding tertiary amines) include aliphatic amines, polyether amines, alicyclic amines, and aromatic amines.

[0220] Examples of 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 tetra(hydroxyethyl)ethylenediamine.

[0221] Examples of polyetheramines include triethylene glycol diamine, tetraethylene glycol diamine, diethylene glycol bis(propylamine), polyoxypropylene diamine, polyoxypropylene triamines, and the like.

[0222] Examples of alicyclic amines include isophoronediamine, methacenediamine, 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 norbornenediamine.

[0223] Examples of aromatic amines include tetrachloro-p-xylylenediamine, m-xylylenediamine, p-xylylenediamine, 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.

[0224] The amine-based curing agents listed above may be used alone or in any combination of two or more in any blending ratio.

[0225] The amine-based curing agent is preferably used so that the equivalent ratio of functional groups in the curing agent to epoxy groups in all epoxy resin components contained in the epoxy resin composition is in the range of 0.1 to 2.0. More preferably, the equivalent ratio is in the range of 0.8 to 1.2. This range is preferable because unreacted epoxy groups and functional groups of the curing agent are less likely to remain.

[0226] [Tertiary amine] Examples of tertiary amines include 1,8-diazabicyclo(5,4,0)undecene-7, triethylenediamine, benzyldimethylamine, triethanolamine, dimethylaminoethanol, and tris(dimethylaminomethyl)phenol. The above-mentioned tertiary amines may be used alone or in any combination of two or more in any blending ratio.

[0227] The above tertiary amine is preferably used so that the equivalent ratio of the functional groups in the curing agent to the epoxy groups in all epoxy resin components contained in the epoxy resin composition is in the range of 0.1 to 2.0. More preferably, the equivalent ratio is in the range of 0.8 to 1.2. This range is preferable because it makes it difficult for unreacted epoxy groups or functional groups of the curing agent to remain.

[0228] [Acid anhydride curing agent] Examples of the acid anhydride curing agent include acid anhydrides and modified acid anhydrides.

[0229] Examples of acid anhydrides include phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, benzophenonetetracarboxylic anhydride, dodecenylsuccinic anhydride, polyadipic anhydride, polyazelaic anhydride, polysebacic anhydride, poly(ethyloctadecanedioic) anhydride, poly(phenylhexadecanedioic) anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, hexahydrophthalic anhydride, methylhimic anhydride, trialkyltetrahydrophthalic anhydride, Examples of the dicarboxylic acid anhydride include methylcyclohexene dicarboxylic acid anhydride, methylcyclohexene tetracarboxylic acid anhydride, ethylene glycol bistrimellitate dianhydride, HET anhydride, Nadic anhydride, methylnadic anhydride, 5-(2,5-dioxotetrahydro-3-furanyl)-3-methyl-3-cyclohexane-1,2-dicarboxylic acid anhydride, 3,4-dicarboxy-1,2,3,4-tetrahydro-1-naphthalene succinic dianhydride, and 1-methyl-dicarboxy-1,2,3,4-tetrahydro-1-naphthalene succinic dianhydride.

[0230] 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, copolymer polyether glycols of two or more of these glycols and / or polyether glycols can also be used.

[0231] The acid anhydride curing agents listed above may be used alone or in any combination of two or more in any amount.

[0232] When an acid anhydride curing agent is used, it is preferably used so that the equivalent ratio of functional groups in the curing agent to epoxy groups in all epoxy resin components in the epoxy resin composition is in the range of 0.1 to 2.0. More preferably, the equivalent ratio is in the range of 0.8 to 1.2. This range is preferable because it makes it difficult for unreacted epoxy groups or functional groups of the curing agent to remain.

[0233] [Amide-based curing agent] Examples of the amide-based curing agent include dicyandiamide and its derivatives, polyamide resins, and the like. The amide curing agent may be used alone or as a mixture of two or more kinds in any combination and ratio. When an amide curing agent is used, it is preferable to use the amide curing agent in an amount of 0.1 to 20 mass % based on the total amount of all epoxy resin components and the amide curing agent in the epoxy resin composition.

[0234] [Imidazoles] Examples of 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- Examples of such imidazoles include 2,4-diamino-6-[2'-ethyl-4'-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 isocyanuric acid adduct, 2-phenylimidazole isocyanuric acid adduct, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, and adducts of epoxy resins with the above imidazoles. Note that, since imidazoles have catalytic activity, they can generally be classified as curing accelerators, but in the present invention they are classified as curing agents. The imidazoles listed above may be used alone or in any combination and ratio of two or more.

[0235] When imidazoles are used, the amount of the imidazoles is preferably 0.1 to 20% by mass based on the total amount of all epoxy resin components and imidazoles in the epoxy resin composition.

[0236] [Other hardeners] In addition to the above-mentioned curing agents, other curing agents can be used in the epoxy resin composition. There are no particular restrictions on the other curing agents that can be used in the epoxy resin composition, and any curing agents generally known as curing agents for epoxy resins can be used. These other curing agents may be used alone or in combination of two or more.

[0237] (Other epoxy resins) The epoxy resin composition may contain an epoxy resin other than the epoxy resin obtained by the epoxy resin production method of the present invention. By containing the other epoxy resin, various physical properties can be improved.

[0238] Other epoxy resins that can be used in the epoxy resin composition include all epoxy resins other than those obtained by the epoxy resin production method of the present invention. Specific examples include bisphenol A type epoxy resins, bisphenol C type epoxy resins, trisphenolmethane type epoxy resins, anthracene type epoxy resins, phenol-modified xylene resin type epoxy resins, bisphenol cyclododecyl type epoxy resins, bisphenol diisopropylidene resorcinol type epoxy resins, bisphenol F type epoxy resins, bisphenol AD ​​type epoxy resins, bisphenol AF type epoxy resins, hydroquinone type epoxy resins, methylhydroquinone type epoxy resins, dibutylhydroquinone type epoxy resins, resorcinol type epoxy resins, methylresorcinol type epoxy resins, biphenol type epoxy resins, tetramethylbiphenol type epoxy resins, tetramethylbisphenol F type epoxy resins, dihydroxydiphenyl ether type epoxy resins, epoxy resins derived from thiodiphenols, dihydroxynaphthalene type epoxy resins, dihydroxyanthracene type epoxy resins, dihydroxydihydroanthracene type epoxy resins, dicyclopentadiene type epoxy resins, dihydrogen Examples of epoxy resins include epoxy resins derived from roxystilbenes, phenol novolac epoxy resins, cresol novolac epoxy resins, bisphenol A novolac epoxy resins, naphthol novolac epoxy resins, phenol aralkyl epoxy resins, naphthol aralkyl epoxy resins, biphenyl aralkyl epoxy resins, terpene phenol epoxy resins, dicyclopentadiene phenol epoxy resins, epoxy resins derived from phenol-hydroxybenzaldehyde condensates, epoxy resins derived from phenol-crotonaldehyde condensates, epoxy resins derived from phenol-glyoxal condensates, epoxy resins derived from co-condensation resins of heavy oils or pitches with phenols and formaldehydes, epoxy resins derived from diaminodiphenylmethane, epoxy resins derived from aminophenols, epoxy resins derived from xylenediamine, epoxy resins derived from methylhexahydrophthalic acid, and epoxy resins derived from dimer acids.These may be used alone or in any combination of two or more in any blending ratio.

[0239] When the epoxy resin composition contains the other epoxy resins described above, the content thereof is preferably 1 to 60 parts by mass, more preferably 40 parts by mass or less, per 100 parts by mass of all epoxy resin components in the composition.

[0240] (curing accelerator) The epoxy resin composition preferably contains a curing accelerator, which enables shortening of the curing time and lowering of the curing temperature, making it easier to obtain a desired cured product.

[0241] The curing accelerator is not particularly limited, but specific examples include organic phosphines, phosphorus compounds such as phosphonium salts, tetraphenylboron salts, organic acid dihydrazides, boron halide amine complexes, and the like.

[0242] Phosphorus compounds that can be used as curing accelerators include triphenylphosphine, diphenyl(p-tolyl)phosphine, tris(alkylphenyl)phosphine, tris(alkoxyphenyl)phosphine, tris(alkylalkoxyphenyl)phosphine, tris(dialkylphenyl)phosphine, tris(trialkylphenyl)phosphine, tris(tetraalkylphenyl)phosphine, tris(dialkoxyphenyl)phosphine, tris(trialkoxyphenyl)phosphine, tris(tetraalkoxyphenyl)phosphine, trialkylphosphine, Examples of such phosphines include organic phosphines such as phosphine, dialkylarylphosphine, and alkyldiarylphosphine; complexes of these organic phosphines with organic borons; and compounds obtained by adding these organic phosphines to quinone compounds such as maleic anhydride, 1,4-benzoquinone, 2,5-toluquinone, 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 diazophenylmethane.

[0243] Among the curing accelerators listed above, organic phosphines and phosphonium salts are preferred, and organic phosphines are most preferred. The curing accelerators listed above may be used alone or in any combination and ratio of two or more.

[0244] The curing accelerator is preferably used in an amount of 0.1 to 20 parts by mass relative to 100 parts by mass of all epoxy resin components in the epoxy resin composition. When the content of the curing accelerator is equal to or greater than the lower limit, a good curing acceleration effect can be obtained, while when the content is equal to or less than the upper limit, the desired cured physical properties can be easily obtained, which is preferred.

[0245] (Inorganic filler) An inorganic filler can be blended into the epoxy resin composition. Examples of inorganic fillers include fused silica, crystalline silica, glass powder, alumina, calcium carbonate, calcium sulfate, talc, boron nitride, etc. These may be used alone or in any combination of two or more in any blending ratio. The blending amount of the inorganic filler is preferably 10 to 95 mass% of the total epoxy resin composition.

[0246] (mold release agent) A mold release agent can be blended into the epoxy resin composition. Examples of the mold release agent 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 mold release agents such as paraffin. These may be used alone or in any combination of two or more in any blending ratio.

[0247] The amount of the release agent is preferably 0.001 to 10.0 parts by mass relative to 100 parts by mass of all epoxy resin components in the epoxy resin composition. When the amount of the release agent is within the above range, good release properties can be exhibited while maintaining curing properties, which is preferable.

[0248] [Coupling agent] A coupling agent can be blended into the epoxy resin composition. The coupling agent is preferably used in combination with an inorganic filler, and blending of the coupling agent can improve the adhesion between the epoxy resin matrix and the inorganic filler. Examples of the coupling agent include a silane coupling agent and a titanate coupling agent.

[0249] 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; mercapto silanes such as 3-mercaptopropyltrimethoxysilane; vinyl silanes such as p-styryltrimethoxysilane, vinyltrichlorosilane, vinyltris(β-methoxyethoxy)silane, vinyltrimethoxysilane, vinyltriethoxysilane, and γ-methacryloxypropyltrimethoxysilane; and polymeric epoxy, amino, and vinyl silanes.

[0250] Examples of titanate coupling agents include isopropyl triisostearoyl titanate, isopropyl tri(N-aminoethyl aminoethyl) titanate, diisopropyl bis(dioctyl phosphate) titanate, tetraisopropyl bis(dioctyl phosphite) titanate, tetraoctyl bis(ditridecyl phosphite) titanate, tetra(2,2-diallyloxymethyl-1-butyl)bis(ditridecyl)phosphite titanate, bis(dioctyl pyrophosphate)oxyacetate titanate, and bis(dioctyl pyrophosphate)ethylene titanate.

[0251] These coupling agents may be used either alone or as a mixture of two or more in any combination and ratio.

[0252] When a coupling agent is used in the epoxy resin composition, the amount thereof is preferably 0.001 to 10.0 parts by mass per 100 parts by mass of the total epoxy resin components. When the amount of the coupling agent is equal to or greater than the lower limit, the effect of improving the adhesion between the epoxy resin matrix and the inorganic filler due to the addition of the coupling agent tends to be enhanced. On the other hand, when the amount of the coupling agent is equal to or less than the upper limit, the coupling agent is less likely to bleed out from the resulting cured product, which is preferable.

[0253] (Other ingredients) The epoxy resin composition may contain components other than those described above. Examples of other components include flame retardants, plasticizers, reactive diluents, pigments, etc., and these can be appropriately added as needed. However, this does not in any way preclude the addition of components other than those listed above.

[0254] Examples of the flame retardant include halogen-based flame retardants such as brominated epoxy resins and brominated phenol resins, antimony compounds such as antimony trioxide, phosphorus-based flame retardants such as red phosphorus, phosphate esters and phosphines, nitrogen-based flame retardants such as melamine derivatives, and inorganic flame retardants such as aluminum hydroxide and magnesium hydroxide.

[0255] (Curing method) A cured epoxy resin product can be obtained by curing an epoxy resin composition. The curing method is not particularly limited, but a cured product can usually be obtained by a thermosetting reaction caused by heating. During the thermosetting reaction, it is preferable to appropriately select the curing temperature depending on the type of curing agent used. For example, when a phenolic curing agent is used, the curing temperature is usually 80 to 250°C. It is also possible to lower the curing temperature by adding a curing accelerator to these curing agents. The reaction time is preferably 0.01 to 20 hours. A reaction time of at least the lower limit is preferred because the curing reaction tends to proceed more efficiently. On the other hand, a reaction time of not more than the upper limit is preferred because it is easy to reduce deterioration due to heating and energy loss during heating.

[0256] (Application) The epoxy resin cured product obtained by curing the epoxy resin composition has a low linear expansion coefficient and excellent heat crack resistance. Therefore, the cured epoxy resins can be effectively used in any application requiring these physical properties, such as in the coatings field (electrodeposition coatings for automobiles, heavy-duty anticorrosion coatings for ships and bridges, and coatings for the interior surfaces of beverage cans), in the electrical and electronics field (laminated plates, semiconductor encapsulants, insulating powder coatings, coil impregnation, etc.), and in the civil engineering, construction, and adhesives field (earthquake-resistant reinforcement of bridges, concrete reinforcement, building flooring, water facility linings, drainage and permeable pavements, and adhesives for vehicles and aircraft).

[0257] The epoxy resin composition may be used for the above-mentioned applications after curing, or may be cured during the manufacturing process for the above-mentioned applications. [Example]

[0258] The present invention will be explained in more detail below with reference to examples and comparative examples, but the present invention is not limited to the following examples as long as it does not depart from the gist of the invention.

[0259] [Raw materials and reagents] The polycarbonate resin used was "NOVAREX (registered trademark) M7027BF" manufactured by Mitsubishi Chemical Engineering Plastics Corporation. Phenol, ortho-cresol, meta-cresol, cresol isomer mixture (ortho-cresol, meta-cresol, and para-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 obtained from Fujifilm Wako Pure Chemical Industries, Ltd. Diphenyl carbonate used was a product of Mitsubishi Chemical Corporation.

[0260] [analysis] The confirmation of the production and purity of bisphenol was carried out by high performance liquid chromatography under the following procedures and conditions. Equipment: Shimadzu LC-2010A, Waters 5μm 150mm x 4.6mm ID Method: Low-pressure gradient method ·Analysis temperature: 40℃ ·Eluent composition: Solution A: Acetonitrile Solution B: 85% phosphoric acid:water = 1 mL:999 mL solution At 0 min of analysis time, the eluent composition was A:B = 35:65 (volume ratio, same below). From 0 to 5 min of analysis time, the eluent composition was maintained at A:B = 35:65, and then gradually changed to A:B = 90:10 from 5 to 40 min of analysis time. ·Flow rate: 0.85mL / min Detection wavelength: 280nm

[0261] The pyridine and phenol contained in the neutralized wastewater were analyzed by gas chromatography according to the following procedure and conditions. Equipment: Shimadzu GC-2014 Agilent DB-1 0.530mm×30m 1.5μm Detection method: FID Vaporization chamber temperature: 230℃ Detector temperature: 300℃ The column temperature was maintained at 50°C for analysis times of 0 to 5 minutes, gradually increased to 280°C for analysis times of 5 to 30 minutes, and maintained at 280°C for analysis times of 30 to 40 minutes. Quantitative method: Internal standard method using biphenyl as an internal standard

[0262] The amount of sodium chloride contained in the neutralized wastewater was calculated from the mass of the residue obtained by evaporating the neutralized wastewater to dryness.

[0263] Dibromophenol contained in the hydrochloric acid wastewater was analyzed by gas chromatography according to the following procedure and conditions. Equipment: Shimadzu GC-2014 Agilent DB-1 0.530mm×30m 1.5μm Detection method: FID Vaporization chamber temperature: 230℃ Detector temperature: 300℃ The column temperature was maintained at 50°C for analysis times of 0 to 5 minutes, gradually increased to 280°C for analysis times of 5 to 30 minutes, and maintained at 280°C for analysis times of 30 to 40 minutes. Quantitation was performed using the absolute calibration curve method.

[0264] The concentration of hydrogen chloride contained in the hydrochloric acid wastewater was measured by neutralization titration using the following apparatus. Apparatus: Kyoto Electronics Manufacturing Co., Ltd. Automatic Potentiometric Titrator AT-610

[0265] The carbon tetrachloride contained in the sodium hydroxide wastewater was analyzed by gas chromatography under the following procedures and conditions. Equipment: Agilent Technologies J&W DB-17 0.32mm x 30m x 0.5μm At analysis time 0 minutes, the column temperature was set to 50°C, and was increased at a rate of 10°C per minute to 250°C. Detector: MS

[0266] The concentration of sodium hydroxide contained in the sodium hydroxide wastewater was measured using the following device. Apparatus: Kyoto Electronics Manufacturing Co., Ltd. Automatic Potentiometric Titrator AT-610

[0267] The sodium chloride concentration contained in the sodium hydroxide wastewater was calculated by measuring the chloride ion concentration using the following device and determining the amount of sodium that is equivalent in mole to the obtained chloride ions. Apparatus: Kyoto Electronics Manufacturing Co., Ltd. Automatic Potentiometric Titrator AT-610

[0268] [Viscosity average molecular weight (Mv)] The viscosity average molecular weight (Mv) was determined by dissolving the polycarbonate resin in methylene chloride (concentration: 6.0 g / L), measuring the specific viscosity (ηsp) at 20°C using an Ubbelohde viscometer, and calculating the viscosity average molecular weight (Mv) using the following formula. ηsp / C=[η](1+0.28ηsp) [η]=1.23×10 -4 Mv 0.83

[0269] [Melted color of bisphenol] The melt color of bisphenol was measured by placing 20 g of bisphenol in a test tube "P-24" (2 mm diameter x 200 mm) manufactured by Nippon Denshoku Glass Co., Ltd., melting it at 174°C for 30 minutes, and measuring the Hazen color number using "OME7700" manufactured by Nippon Denshoku Industries Co., Ltd.

[0270] [pH measurement] The pH was measured using a pH meter "pH METER ES-73" manufactured by Horiba Ltd., with respect to the aqueous phase at 25°C taken out of the flask.

[0271] Example 1 [Example 1-1] In a jacketed separable flask equipped with a Dimroth condenser, a stirring blade, and a thermometer, 80 g of polycarbonate resin (the repeating unit of polycarbonate resin is 254 g / mol, so 80 g ÷ 254 g / mol = 0.315 mol in terms of repeating units), 30 g of water, 250 g of phenol, and 320 g of 25% by mass aqueous sodium hydroxide solution were placed at room temperature under a nitrogen atmosphere. The reaction liquid was in the form of a slurry. 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, to obtain a homogeneous solution. To the resulting homogeneous solution, 200 g of toluene was added, and then 35% by mass hydrochloric acid was added until the pH of the aqueous phase reached 8.6, resulting in the generation of carbon dioxide gas. Thereafter, stirring was stopped to separate the oil and water, and the aqueous phase was extracted from the flask to obtain organic phase 1. When the composition of a portion of the obtained organic phase 1 was confirmed by high performance liquid chromatography, the production of bisphenol A was confirmed.

[0272] 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, and while monitoring the amount of distillate, the internal temperature was gradually increased to 180°C, and the internal pressure was gradually reduced from atmospheric pressure to 100 hPa, to distill off water, toluene, and phenol. Thereafter, the pressure inside 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 demineralized water to obtain an organic phase 3.

[0273] The obtained organic phase 3 was cooled to 20°C to obtain a slurry, which was then filtered to obtain a cake. The obtained cake was dried using a rotary evaporator to obtain 35 g of bisphenol A. The purity of the obtained bisphenol A was 99.8 mass % and the melt color was APHA165.

[0274] [Example 1-2] The same procedure as in Example 1-1 was repeated, except that 320 g of a 25% by mass aqueous solution of potassium hydroxide was used instead of 320 g of a 25% by mass aqueous solution of sodium hydroxide in Example 1-1. The amount of bisphenol A obtained was 41 g, with a purity of 99.8% by mass and a melt color of APHA157.

[0275] Example 2 In a jacketed separable flask equipped with a Dimroth condenser, a stirring blade, and a thermometer, 80 g of polycarbonate resin (0.315 mol in terms of repeating unit), 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 liquid was in the form of a slurry. 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, to obtain a homogeneous solution. The composition of a portion of the obtained homogeneous solution was confirmed by high performance liquid chromatography, and it was found that 19.2% by mass of bisphenol A was produced. 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, and the reaction rate was 0.312 mol ÷ 0.315 mol × 100 = 99%.

[0276] Example 3 [Example 3-1] In a jacketed separable flask equipped with a Dimroth 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 methylamine solution were placed at room temperature under a nitrogen atmosphere. The reaction liquid was in the form of a slurry. 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 homogeneous solution. During the reaction, the generation of carbon dioxide was confirmed. A portion of the resulting homogeneous solution was taken out and the composition was confirmed by high performance liquid chromatography, which revealed that bisphenol A was produced in an amount of 19.9 mass %. The mass of the homogeneous solution was 80 g + 30 g + 240 g + 2 g = 352 g, and the amount of bisphenol produced was 19.9 mass% × 352 g ÷ 228.29 g / mol = 0.307 mol, and the reaction rate was 0.307 mol ÷ 0.315 mol × 100 = 97%.

[0277] [Example 3-2] The same procedure as in Example 3-1 was carried out, except that 2 g of a 50% by mass aqueous solution of dimethylamine was added instead of 2 g of a 40% by mass aqueous solution of methylamine. A portion of the resulting homogeneous solution was taken out and the composition was confirmed by high performance liquid chromatography, which revealed that bisphenol A was produced in an amount of 19.6 mass %. The mass of the homogeneous solution was 80 g + 30 g + 240 g + 2 g = 352 g, and the amount of bisphenol produced was 19.6 mass% × 352 g ÷ 228.29 g / mol = 0.302 mol, and the reaction rate was 0.302 mol ÷ 0.315 mol × 100 = 96%.

[0278] [Example 3-3] The same procedure as in Example 3-1 was carried out, except that 5 g of an aqueous trimethylamine solution was added instead of 2 g of a 40% by mass aqueous methylamine solution. A portion of the resulting homogeneous solution was taken out and the composition was confirmed by high performance liquid chromatography, which revealed that bisphenol A was produced in an amount of 19.6 mass %. The mass of the homogeneous solution was 80 g + 30 g + 240 g + 5 g = 355 g, and the amount of bisphenol produced was 19.6 mass% × 355 g ÷ 228.29 g / mol = 0.304 mol, and the reaction rate was 0.304 mol ÷ 0.315 mol × 100 = 97%.

[0279] [Example 3-4] The same procedure as in Example 3-1 was carried out, except that 5 g of a 70% by mass aqueous solution of ethylamine was added instead of 2 g of a 40% by mass aqueous solution of methylamine. A portion of the resulting homogeneous solution was taken out and the composition was confirmed by high performance liquid chromatography, which revealed that bisphenol A was produced in an amount of 20.1% by mass. The mass of the homogeneous solution was 80 g + 30 g + 240 g + 5 g = 355 g, and the amount of bisphenol produced was 20.1 mass% × 355 g ÷ 228.29 g / mol = 0.313 mol, and the reaction rate was 0.313 mol ÷ 0.315 mol × 100 = 99%.

[0280] [Examples 3-5] The same procedure as in Example 3-1 was carried out, except that 10 g of diethylamine was added instead of 2 g of the 40% by mass aqueous methylamine solution. A portion of the resulting homogeneous solution was taken out and the composition was confirmed by high performance liquid chromatography, which revealed that bisphenol A was produced in an amount of 19.7 mass %. The mass of the homogeneous solution was 80 g + 30 g + 240 g + 10 g = 360 g, and the amount of bisphenol produced was 19.7 mass% × 360 g ÷ 228.29 g / mol = 0.311 mol, and the reaction rate was 0.311 mol ÷ 0.315 mol × 100 = 99%.

[0281] [Examples 3-6] The same procedure as in Example 3-1 was carried out, except that 10 g of triethylamine was added instead of 2 g of the 40% by mass aqueous methylamine solution. A portion of the resulting homogeneous solution was taken and its composition was confirmed by high-performance liquid chromatography, revealing that the production of bisphenol A was 19.6% by mass. The mass of the homogeneous solution was 80 g + 30 g + 240 g + 10 g = 360 g, and the amount of bisphenol produced was 19.6% by mass × 360 g ÷ 228.29 g / mol = 0.309 mol, giving a reaction rate of 0.309 mol ÷ 0.315 mol × 100 = 98%.

[0282] [Examples 3-7] The same procedure as in Example 3-1 was carried out, except that 10 g of tripropylamine was added instead of 2 g of the 40% by mass aqueous methylamine solution. A portion of the resulting homogeneous solution was taken and its composition was confirmed by high-performance liquid chromatography, revealing that the production of bisphenol A was 19.4% by mass. The mass of the homogeneous solution was 80 g + 30 g + 240 g + 10 g = 360 g, and the produced bisphenol was 19.4% by mass × 360 g ÷ 228.29 g / mol = 0.306 mol, giving a reaction rate of 0.306 mol ÷ 0.315 mol × 100 = 97%.

[0283] Table 1 shows the results of Examples 3-1 to 3-7.

[0284] [Table 1]

[0285] [Examples 3-8] The same procedure as in Example 3-6 was carried out except that, instead of raising the internal temperature to 80°C and maintaining it at 80°C for 5 hours while reacting, the internal temperature was raised to 70°C and maintaining it at 70°C for 5 hours while reacting. A portion of the resulting solution was taken and its composition was confirmed by high-performance liquid chromatography, revealing that 6.5% by mass of bisphenol A was produced. The mass of the solution was 80 g + 30 g + 240 g + 10 g = 360 g, and the amount of bisphenol produced was 6.5% by mass × 360 g ÷ 228.29 g / mol = 0.103 mol, giving a reaction rate of 0.103 mol ÷ 0.315 mol × 100 = 33%.

[0286] [Example 3-8-2] 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 5 hours while maintaining the temperature at 70°C in Example 3-8. A portion of the resulting solution was taken and its composition was confirmed by high-performance liquid chromatography, revealing that the production of bisphenol A was 13.1% by mass. The mass of the solution was 80 g + 30 g + 240 g + 10 g = 360 g, and the amount of bisphenol produced was 13.1% by mass × 360 g ÷ 228.29 g / mol = 0.207 mol, giving a reaction rate of 0.207 mol ÷ 0.315 mol × 100 = 66%.

[0287] Table 2 shows the results of Examples 3-8 to 3-8-2.

[0288] [Table 2]

[0289] [Examples 3-9] The same procedure as in Example 3-6 was carried out except that, instead of raising the internal temperature to 80°C and maintaining it at 80°C for 5 hours while reacting, the internal temperature was raised to 60°C and maintained at 60°C for 5 hours while reacting. A portion of the resulting solution was taken and its composition was confirmed by high-performance liquid chromatography, revealing that the production of bisphenol A was 1.8% by mass. The mass of the solution was 80 g + 30 g + 240 g + 10 g = 360 g, and the amount of bisphenol produced was 1.8% by mass × 360 g ÷ 228.29 g / mol = 0.028 mol, giving a reaction rate of 0.028 mol ÷ 0.315 mol × 100 = 9%.

[0290] [Example 3-9-2] The same procedure as in Example 3-9 was carried out, except that the reaction was carried out for 56 hours while maintaining the temperature at 60°C instead of 5 hours while maintaining the temperature at 60°C in Example 3-9. A portion of the resulting solution was taken and its composition was confirmed by high-performance liquid chromatography, revealing that 12.9% by mass of bisphenol A was produced. The mass of the solution was 80 g + 30 g + 240 g + 10 g = 360 g, and the amount of bisphenol produced was 12.9% by mass × 360 g ÷ 228.29 g / mol = 0.203 mol, giving a reaction rate of 0.203 mol ÷ 0.315 mol × 100 = 64%.

[0291] Table 3 shows the results of Examples 3-9 to 3-9-2.

[0292] [Table 3]

[0293] [Comparative Example 3-1] In a jacketed separable flask equipped with a Dimroth 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 methylene chloride, and 2 g of a 40% by mass aqueous methylamine solution were placed at room temperature under a nitrogen atmosphere. Thereafter, since the boiling point of methylene chloride 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. A portion of the resulting homogeneous solution was taken out and its composition was confirmed by high performance liquid chromatography, revealing that only a trace amount of bisphenol A was found.

[0294] [Comparative Example 3-2] The same procedure as in Example 3-6 was carried out, except that 30 g of water was not used. No generation of carbon dioxide was confirmed during the reaction. A portion of the resulting homogeneous solution was taken out and the composition was confirmed by high performance liquid chromatography, which revealed that bisphenol A was produced in an amount of 13.1% by mass. The mass of the homogeneous solution was 80 g + 240 g + 10 g = 330 g, and the amount of bisphenol produced was 13.1 mass% × 322 g ÷ 228 g / mol = 0.190 mol, and the reaction rate was 0.190 mol ÷ 0.315 mol × 100 = 60%.

[0295] Furthermore, the amount of bisphenol A produced remained at the same level even when the reaction time was extended.

[0296] [Comparative Example 3-3] Comparative Example 3-2 was repeated except that the reaction temperature was changed from 80° C. to 60° C. No carbon dioxide was generated during the reaction. A portion of the resulting homogeneous solution was taken out and the composition was confirmed by high performance liquid chromatography, which revealed that the amount of bisphenol A produced was only trace.

[0297] Furthermore, the amount of bisphenol A produced did not change even when the reaction time was extended.

[0298] [Comparative Example 3-4] The same procedure as in Example 3-6 was carried out, except that 240 g of phenol was not used. In the resulting reaction liquid, most of the supplied polycarbonate resin remained as a solid. A portion of the resulting reaction liquid was taken out and its composition was confirmed by high performance liquid chromatography, which revealed that a trace amount of bisphenol A had been produced.

[0299] Table 4 shows the results of Comparative Examples 3-1 to 3-4.

[0300] [Table 4]

[0301] Tables 1 to 4 show that the combined use of phenol and water enables efficient decomposition of polycarbonate resin. Furthermore, since no chlorinated hydrocarbon solvents such as methylene chloride are used, this decomposition method places a small burden on the environment. Furthermore, in Examples 3-1 to 3-9-2, polycarbonate resin is decomposed into bisphenol A and carbon dioxide, making it easy to recover and purify bisphenol A.

[0302] [Example 3-10] The reaction liquid 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 monitoring the amount of distillate, the internal temperature was gradually increased to 180°C, and the internal pressure was gradually reduced from atmospheric pressure to 100 hPa to distill off water, triethylamine, and phenol. Thereafter, the pressure inside 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. The obtained organic phase 1 was washed five times with 50 g of demineralized water to obtain 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 cake. The obtained cake was dried using a rotary evaporator to obtain 32 g of bisphenol A. The purity of the obtained bisphenol A was 99.8 mass % and the melt color was APHA155.

[0303] Example 4 [Example 4-1] A jacketed separable flask equipped with a Dimroth condenser, a stirring blade, and a thermometer was charged with 240 g of ortho-cresol and 30 g of water under a nitrogen atmosphere, and then 15 g of triethylamine was added and stirred. Then, 80 g of polycarbonate resin (0.315 mol in terms of repeating units) was added. 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, to obtain a homogeneous solution. A portion of the resulting homogeneous solution was taken and its composition was confirmed by high-performance liquid chromatography, revealing that the production of bisphenol A was 19.4% by mass. The mass of the homogeneous solution was 240 g + 30 g + 15 g + 80 g = 365 g, and the produced bisphenol was 19.4% by mass × 365 g ÷ 228.29 g / mol = 0.310 mol, resulting in a reaction rate of 0.310 mol ÷ 0.315 mol × 100 = 98%.

[0304] The resulting reaction liquid was cooled to 20°C and allowed to stand for 12 hours to obtain a slurry liquid. The resulting slurry liquid was filtered under reduced pressure to obtain cake 1. The obtained cake 1 was suspended and washed with toluene to obtain 21 g of cake 2. The composition of a portion of Cake 2 was confirmed by high-performance liquid chromatography, which revealed that it contained 0.5% ortho-cresol and 78.2% bisphenol A. The amount of ortho-cresol contained in Cake 2 was 21 g × 0.5% by mass ÷ 108 g / mol = 1 mmol, and the amount of bisphenol A was 21 g × 78.2% by mass ÷ 228 g / mol = 72 mmol, indicating that it was a cake of bisphenol A.

[0305] [Example 4-2] The same procedure as in Example 4-1 was carried out, except that meta-cresol was used instead of ortho-cresol. 20 g of cake 2 was obtained. The composition of a portion of Cake 2 was confirmed by high-performance liquid chromatography, which revealed that it contained 0.6% by mass of meta-cresol and 78.5% by mass of bisphenol A. The amount of meta-cresol contained in Cake 2 was 20 g × 0.6% by mass ÷ 108 g / mol = 1 mmol, and the amount of bisphenol A was 20 g × 78.5% by mass ÷ 228 g / mol = 69 mmol, indicating that it was a cake of bisphenol A.

[0306] [Example 4-3] The same procedure as in Example 4-1 was repeated, except that a cresol isomer mixture was used instead of ortho-cresol. 22 g of cake 2 was obtained. The composition of a portion of Cake 2 was confirmed by high-performance liquid chromatography, which revealed that the cresol isomer mixture was 0.3% by mass and the bisphenol A content was 79.7% by mass. The cresol isomer mixture contained in Cake 2 was 22 g × 0.3% by mass ÷ 108 g / mol = 1 mmol, and the bisphenol A content was 22 g × 79.7% by mass ÷ 228 g / mol = 77 mmol, indicating that the cake was a bisphenol A cake.

[0307] [Example 4-4] The 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 demineralized water were then added, and the temperature was raised to 80°C to obtain organic phase 1. The obtained organic phase 1 was washed five times with 50 g of demineralized water to obtain organic phase 2. The obtained organic phase 2 was cooled to 20°C to obtain a slurry, which was then filtered to obtain a cake. The resulting cake was dried using a rotary evaporator to obtain 11 g of bisphenol A. The purity of the obtained bisphenol A was 99.8% by mass, and the melt color was APHA95.

[0308] Example 5 The same procedure as in Example 4-1 was carried out, except that phenol was used instead of ortho-cresol. 25 g of cake 2 was obtained. When the composition of a portion of Cake 2 was confirmed by high-performance liquid chromatography, it was found to be 23% by mass of phenol and 57% by mass of bisphenol A. The amount of phenol contained in Cake 2 was 25 g × 23% by mass ÷ 94 g / mol = 61 mmol, and the amount of bisphenol A was 25 g × 57% by mass ÷ 228 g / mol = 63 mmol, indicating that it was a cake of co-crystals of phenol and bisphenol A.

[0309] Table 5 summarizes the organic solvents and cakes in Examples 4-1 to 4-3 and Example 5. The results of Examples 4-1 to 4-3 show that by using cresol, a cake of bisphenol A can be obtained without distilling off phenol. Furthermore, the results of Example 5 show that when crystallization is carried out in the coexistence of phenol, a co-crystal of bisphenol A and phenol is obtained.

[0310] [Table 5]

[0311] Example 6 [Example 6-1] In a jacketed separable flask equipped with a Dimroth condenser, a stirring blade, and a thermometer, 80 g of polycarbonate resin (0.315 mol in terms of repeating unit), 100 g of water, 240 g of phenol, and 80 g of p-toluenesulfonic acid were placed at room temperature under a nitrogen atmosphere. 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, the generation of carbon dioxide was confirmed. A portion of the resulting reaction solution was taken and its composition was confirmed by high-performance liquid chromatography, revealing that 13.2% by mass of bisphenol A was produced. The mass of the reaction solution was 80 g + 100 g + 240 g + 80 g = 500 g, and the amount of bisphenol A produced was 13.2% by mass × 500 g ÷ 228.29 g / mol = 0.289 mol, giving a reaction rate of 0.289 mol ÷ 0.315 mol × 100 = 92%.

[0312] [Example 6-2] The same procedure as in Example 6-1 was repeated, except that 40 g of methanesulfonic acid was added instead of 80 g of p-toluenesulfonic acid. A portion of the resulting reaction solution was taken and its composition was confirmed by high-performance liquid chromatography, revealing that 14.3% by mass of bisphenol A was produced. The mass of the reaction solution was 80 g + 100 g + 240 g + 40 g = 460 g, and the amount of bisphenol A produced was 14.3% by mass × 460 g ÷ 228.29 g / mol = 0.288 mol, giving a reaction rate of 0.288 mol ÷ 0.315 mol × 100 = 91%.

[0313] [Example 6-3] The same procedure as in Example 6-1 was carried out, except that 240 g of 35% hydrochloric acid was added instead of 80 g of p-toluenesulfonic acid. A portion of the resulting reaction solution was taken and its composition was confirmed by high-performance liquid chromatography, revealing that 8.5% by mass of bisphenol A was produced. The mass of the reaction solution was 80 g + 100 g + 240 g + 240 g = 660 g, and the amount of bisphenol A produced was 8.5% by mass × 660 g ÷ 228.29 g / mol = 0.246 mol, giving a reaction rate of 0.246 mol ÷ 0.315 mol × 100 = 78%.

[0314] [Example 6-4] The same procedure as in Example 6-1 was carried out, except that 100 g of 98% sulfuric acid was added instead of 80 g of p-toluenesulfonic acid. A portion of the resulting reaction solution was taken and its composition was confirmed by high-performance liquid chromatography, revealing that 11.8% by mass of bisphenol A was produced. The mass of the reaction solution was 80 g + 100 g + 240 g + 100 g = 520 g, and the amount of bisphenol A produced was 11.8% by mass × 520 g ÷ 228.29 g / mol = 0.269 mol, giving a reaction rate of 0.269 mol ÷ 0.315 mol × 100 = 85%.

[0315] [Example 6-5] The same procedure as in Example 6-1 was carried out, except that 200 g of 85% phosphoric acid was added instead of 80 g of p-toluenesulfonic acid. A portion of the resulting reaction solution was taken and its composition was confirmed by high-performance liquid chromatography, revealing that 9.6% by mass of bisphenol A was produced. The mass of the reaction solution was 80 g + 100 g + 240 g + 200 g = 620 g, and the amount of bisphenol A produced was 9.6% by mass × 620 g ÷ 228.29 g / mol = 0.261 mol, giving a reaction rate of 0.261 mol ÷ 0.315 mol × 100 = 83%.

[0316] The acids and reaction rates for Examples 6-1 to 6-5 are summarized in Table 6. As a result, it is found that the polycarbonate resin can be decomposed by using an acid.

[0317] [Table 6]

[0318] [Example 6-6] To the reaction liquid obtained in Example 6-1, 200 g of toluene was added, and then a 25% aqueous sodium hydroxide solution was added to adjust the pH to 9.1. The aqueous phase was removed, and an organic phase 1 was obtained.

[0319] The obtained organic phase 1 was transferred to a distillation apparatus equipped with a thermometer, stirring blade, distillation tube, and pressure regulator. While monitoring the distillate amount, the internal temperature was gradually increased to 180°C, and the internal pressure was gradually reduced from normal pressure to 100 hPa to distill off water and phenol. The flask was then repressurized with nitrogen, the internal temperature was reduced to 80°C, and 200 g of toluene was added to obtain organic phase 2. The obtained organic phase 2 was washed five times with 50 g of demineralized water to obtain organic phase 3.

[0320] The obtained organic phase 3 was cooled to 20°C to obtain a slurry. The obtained slurry was filtered to obtain a cake. The obtained cake was dried using a rotary evaporator to obtain 25 g of bisphenol A. The purity of the obtained bisphenol A was 99.8 mass% and the melt color was APHA162.

[0321] Example 7 [Example 7-1] A 45 mL glass reactor equipped with a stirrer and a distillation tube was charged with 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 aqueous cesium carbonate solution. The glass reactor was depressurized to approximately 100 Pa, and then the pressure was returned to atmospheric pressure with nitrogen. This operation was repeated three times to replace the inside of the reactor with nitrogen. The reactor was then immersed in an oil bath at 220°C to dissolve the contents.

[0322] The agitator was rotated at 100 revolutions per minute, and the pressure inside the reactor was reduced from 101.3 kPa absolute to 13.3 kPa over 40 minutes while distilling off the phenol by-product from the oligomerization reaction of bisphenol A and diphenyl carbonate in the reactor. The pressure inside the reactor was then maintained at 13.3 kPa, and the transesterification reaction was carried out for 80 minutes while further distilling off the phenol. The temperature outside the reactor was then raised to 290°C, and the pressure inside the reactor was reduced from 13.3 kPa absolute to 399 Pa over 40 minutes, and the distilled phenol was removed from the system. The absolute pressure inside the reactor was then reduced to 30 Pa, and the polycondensation reaction was carried out. The polycondensation reaction was terminated when the agitator in the reactor reached a predetermined stirring power. The time from raising the temperature to 290°C to completing the polymerization was 120 minutes.

[0323] Next, the reactor was restored to an absolute pressure of 101.3 kPa with nitrogen, and then the pressure was increased to a gauge pressure of 0.2 MPa, and the polycarbonate resin was extracted from the reactor to obtain a recycled polycarbonate resin. The viscosity average molecular weight (Mv) of the resulting recycled polycarbonate resin was 27,100.

[0324] [Example 7-2] Example 7-1 was carried out in the same manner as in Example 7-1, except that the bisphenol A obtained in Example 3-10 was used instead of the bisphenol A obtained in Example 1-1. The viscosity average molecular weight (Mv) of the resulting recycled polycarbonate resin was 26,800.

[0325] [Example 7-3] Example 7-1 was carried out in the same manner as in Example 7-1, except that the bisphenol A obtained in Example 4-4 was used instead of the bisphenol A obtained in Example 1-1. The viscosity average molecular weight (Mv) of the resulting recycled polycarbonate resin was 24,000.

[0326] [Example 7-4] Example 7-1 was carried out in the same manner as in Example 7-1, except that the bisphenol A obtained in Example 6-6 was used instead of the bisphenol A obtained in Example 1-1. The viscosity average molecular weight (Mv) of the resulting recycled polycarbonate resin was 26,000.

[0327] Example 8 [Example 8-1] 8-1-1: Acquisition of neutralized wastewater Diphenyl carbonate was produced according to Example 12 (2) Production of Diphenyl Carbonate (paragraphs 0050-0051) of Patent Document JP-A-2004-345883, and the aqueous phase resulting from separation in the neutralization mixing tank was collected as neutralization wastewater. The composition of the obtained neutralization wastewater was 0.3 mass % pyridine, 1.4 mass % phenol, and 4 mass % sodium chloride.

[0328] 8-1-2: Production of bisphenol (decomposition of polycarbonate resin) Polycarbonate resin (80 g, 0.315 moles in terms of repeating units), pyridine (2 g), the neutralization wastewater (29 g) obtained in 8-1-1, and phenol (240 g) were placed in a jacketed separable flask equipped with a Dimroth condenser, a stirring blade, and a thermometer 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. The temperature was then raised to 85°C, and the reaction was carried out for 4 hours while maintaining the temperature at 85°C.

[0329] The composition of a portion of the resulting reaction liquid was confirmed by high performance liquid chromatography, and it was found to contain 15.5% by mass of bisphenol A (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%).

[0330] The resulting reaction liquid was transferred to a distillation apparatus equipped with a thermometer, a stirring blade, a distillation tube, and a pressure regulator, and while monitoring the amount of distillate, the internal temperature was gradually increased to 180°C, and the internal pressure was gradually reduced from atmospheric pressure to 10 kPa to distill off water, pyridine, and phenol. Thereafter, the pressure inside 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. The obtained organic phase 1 was washed five times with 50 g of demineralized water to obtain 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 cake. The resulting 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.

[0331] [Example 8-2] Reagent sodium chloride and water (demineralized water) were mixed so that the sodium chloride concentration was 4% by mass, to obtain a 4% by mass aqueous sodium chloride solution (make-up aqueous sodium chloride solution). Example 8-1 was repeated except that the neutralization wastewater (29 g) was replaced with the make-up aqueous sodium chloride solution (29 g). The composition of a portion of the resulting reaction liquid was confirmed by high performance liquid chromatography, and it was found to contain 14.6% by mass of bisphenol A (14.6 ÷ 100 × 351 g = 51.2 g, decomposition rate of polycarbonate resin: 51.2 g ÷ 228 g / mol ÷ 0.315 mol × 100 = 71.3 mol%).

[0332] [Example 8-3] The same procedure as in Example 8-1 was carried out, except that water (demineralized water) (29 g) was used instead of the neutralization wastewater (29 g). The composition of a portion of the resulting reaction liquid was confirmed by high performance liquid chromatography, and it was found to contain 14.2 mass% bisphenol A (14.2 ÷ 100 × 351 g = 49.8 g, decomposition rate of polycarbonate resin: 49.8 g ÷ 228 g / mol ÷ 0.315 mol × 100 = 69.3 mol%).

[0333] Table 7 summarizes the types of catalysts and organic solvents, the use or nonuse of water, sodium chloride, and wastewater, and the reaction rate (polycarbonate resin decomposition rate) 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 sodium chloride is not used. It also shows that wastewater from a diphenyl carbonate plant can be used. Since wastewater from a diphenyl carbonate plant can be used, the wastewater can be recycled, resulting in a low environmental impact.

[0334] [Table 7]

[0335] [Example 8-4] Example 7-1 was carried out in the same manner as in Example 7-1, 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 raising the temperature to 290°C to completing the polymerization was changed from 120 minutes to 140 minutes. The viscosity average molecular weight (Mv) of the resulting recycled polycarbonate resin was 26,900.

[0336] Example 9 [Example 9-1] 9-1-1: Acquisition of hydrochloric acid wastewater Chlorine was produced according to the procedure of Example 12, (3) Production of Chlorine (paragraphs 0055-0058) of Patent Document JP-A-2004-345883, and hydrochloric acid solution continuously extracted from the bottom of the stripping distillation column was obtained as hydrochloric acid wastewater. The composition of the obtained hydrochloric acid wastewater was 18 mass% hydrogen chloride and 50 mass ppm dibromophenol.

[0337] 9-1-2: Production of bisphenol (decomposition of polycarbonate resin) In a jacketed separable flask equipped with a Dimroth condenser, a stirring blade, and a thermometer, polycarbonate resin (80 g, 0.315 moles in terms of repeating units), the hydrochloric acid wastewater (300 g) obtained in 9-1-1, and phenol (200 g) were placed at room temperature under a nitrogen atmosphere. 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. The temperature was then raised to 80°C, and the reaction was carried out for 60 minutes while maintaining the temperature at 80°C.

[0338] The composition of a portion of the resulting reaction liquid was confirmed by high performance liquid chromatography, and it was found to contain 8.0% by mass of bisphenol A (8.0 ÷ 100 × 580 g = 46.4 g, decomposition rate of polycarbonate resin: 46.4 g ÷ 228 g / mol ÷ 0.315 mol × 100 = 64.6 mol%).

[0339] [Example 9-2] A hydrochloric acid solution (make-up hydrochloric acid waste solution) was obtained by mixing dibromophenol as a reagent, 35% hydrochloric acid as a reagent, and water (demineralized water) so that the dibromophenol concentration was 50 mass ppm and the hydrogen chloride concentration was 18 mass %. The same procedure as in Example 9-1 was carried out, except that the make-up hydrochloric acid waste solution (300 g) was used instead of the hydrochloric acid waste water (300 g). The composition of a portion of the resulting reaction liquid was confirmed by high performance liquid chromatography, and it was found to be 7.7 mass% bisphenol A (7.7 ÷ 100 × 580 g = 44.7 g, decomposition rate of polycarbonate resin: 44.7 g ÷ 228 g / mol ÷ 0.315 mol × 100 = 62.2 mol%).

[0340] [Example 9-3] Using 35% hydrochloric acid as a reagent and water (demineralized water), an aqueous hydrochloric acid solution (make-up hydrochloric acid solution) containing 18% by mass of hydrogen chloride was prepared. The same procedure as in Example 9-1 was carried out, except that the 18% by mass hydrochloric acid (make-up hydrochloric acid solution) (300 g) was used instead of the hydrochloric acid wastewater (300 g). The composition of a portion of the resulting reaction liquid was confirmed by high performance liquid chromatography, and it was found to be 6.9% by mass of bisphenol A (6.9 ÷ 100 × 580 g = 40.0 g, decomposition rate of polycarbonate resin: 40.0 g ÷ 228 g / mol ÷ 0.315 mol × 100 = 55.7 mol%).

[0341] Table 8 summarizes the types of catalysts and organic solvents, the use or nonuse of water, dibromophenol, and wastewater, and the reaction rate (polycarbonate resin decomposition rate) for Examples 9-1 to 9-3. Table 8 shows that polycarbonate resin can be decomposed using hydrochloric acid wastewater discharged from a plant for recovering hydrogen chloride, a by-product of diphenyl carbonate production. The use of hydrochloric acid wastewater makes it possible to recycle the wastewater, and it also shows that the environmental impact is low. It is also clear that the inclusion of dibromophenol increases the decomposition rate of polycarbonate resin.

[0342] [Table 8]

[0343] [Example 9-4] 600 g of toluene was added to the reaction mixture obtained in Example 9-1 and the temperature was raised to 80°C. Then, an aqueous solution of sodium hydroxide and an aqueous solution of sodium bicarbonate were added until the pH of the aqueous phase reached 8.5. Thereafter, stirring was stopped to separate the oil and water, and the aqueous phase was extracted from the flask to obtain an organic phase 1. 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, and while monitoring the amount of distillate, the internal temperature was gradually increased to 180°C, and the internal pressure was gradually reduced from normal pressure to 10 kPa to distill off water, toluene, and phenol. Thereafter, the pressure inside 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 demineralized water to obtain an organic phase 3.

[0344] The obtained organic phase 3 was cooled to 20°C to obtain a slurry, which was then filtered to obtain a cake. The resulting 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.

[0345] [Example 9-5] Example 7-1 was carried out in the same manner as in Example 7-1, 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 raising the temperature to 290°C to completing the polymerization was changed from 120 minutes to 140 minutes. The viscosity average molecular weight (Mv) of the resulting recycled polycarbonate resin was 27,200.

[0346] Example 10 [Example 10-1] 10-1-1: Acquisition of sodium hydroxide wastewater Phosgene was produced according to the method described in Example 12 of Japanese Patent Application Laid-Open No. 2004-345883, "Production of Phosgene (1)," and a portion of the caustic soda was extracted from a detoxification tower in which the aqueous caustic soda solution was circulated to obtain sodium hydroxide wastewater. The resulting sodium hydroxide wastewater had a composition of 50 ppm by mass of carbon tetrachloride, 0.1% by mass of sodium chloride, and 25% by mass of sodium hydroxide.

[0347] 10-1-2: Production of bisphenol (decomposition of polycarbonate resin) In a jacketed separable flask equipped with a Dimroth condenser, a stirring blade, and a thermometer, polycarbonate resin (80 g, 0.315 moles in terms of repeating units), the sodium hydroxide wastewater (80 g) obtained in 10-1-1, water (40 g), and phenol (400 g) were placed at room temperature under a nitrogen atmosphere. 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. Thereafter, the temperature was raised to 60°C and the reaction was carried out for 70 minutes while maintaining the temperature at 60°C. The composition of a portion of the resulting reaction liquid was confirmed by high performance liquid chromatography, and it was found to contain 9.2 mass% bisphenol A (9.2 ÷ 100 × 600 g = 55.2 g, decomposition rate of polycarbonate resin: 55.2 g ÷ 228 g / mol ÷ 0.315 mol × 100 = 76.9 mol%).

[0348] [Example 10-2] Reagent carbon tetrachloride, reagent sodium chloride, reagent sodium hydroxide, and water (demineralized water) were mixed so that the carbon tetrachloride concentration was 50 mass ppm, the sodium chloride concentration was 0.1 mass%, and the sodium hydroxide concentration was 25 mass%, to obtain an aqueous sodium hydroxide solution (make-up sodium hydroxide waste liquid). The same procedure as in Example 10-1 was carried out, except that the sodium hydroxide wastewater (80 g) was replaced with the make-up sodium hydroxide wastewater (80 g). The composition of a portion of the resulting reaction liquid was confirmed by high performance liquid chromatography, and it was found to contain 8.9% by mass of bisphenol A (8.9 ÷ 100 × 600 g = 53.4 g, decomposition rate of polycarbonate resin: 53.4 g ÷ 228 g / mol ÷ 0.315 mol × 100 = 74.3 mol%).

[0349] [Example 10-3] A 25% by mass aqueous solution of sodium hydroxide (make-up aqueous solution of sodium hydroxide) was prepared using sodium hydroxide as a reagent and water (demineralized water). The same procedure as in Example 10-1 was carried out, except that the make-up aqueous sodium hydroxide solution (80 g) was used instead of the sodium hydroxide wastewater (80 g). The composition of a portion of the resulting reaction liquid was confirmed by high performance liquid chromatography, and it was found to contain 8.5% by mass of bisphenol A (8.5 ÷ 100 × 600 g = 51.0 g, decomposition rate of polycarbonate resin: 51.0 g ÷ 228 g / mol ÷ 0.315 mol × 100 = 71.0 mol%).

[0350] Table 9 summarizes the types of catalyst and organic solvent, the use or nonuse of water, carbon tetrachloride, sodium chloride, and wastewater, and the reaction rate (polycarbonate resin decomposition rate) for Examples 10-1 to 10-3. Table 9 shows that polycarbonate resin can be decomposed using sodium hydroxide wastewater discharged from the detoxification treatment facility of a carbonyl chloride (phosgene) manufacturing plant. Since sodium hydroxide wastewater can be used, wastewater can be recycled and the environmental load is low. It also shows that the use of sodium hydroxide wastewater increases the polycarbonate resin decomposition rate.

[0351] [Table 9]

[0352] [Example 10-4] In a jacketed separable flask equipped with a Dimroth condenser, a stirring blade, and a thermometer, polycarbonate resin (80 g, 0.315 moles in terms of repeating units), the sodium hydroxide wastewater (80 g) obtained in Example 10-1, 10-1-1, water (40 g), and phenol (400 g) were placed at room temperature under a nitrogen atmosphere. 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. Thereafter, the temperature was raised to 80°C and the reaction was carried out for 70 minutes while maintaining the temperature at 80°C. The composition of a portion of the resulting reaction liquid was confirmed by high performance liquid chromatography, and it was found to contain 11.8% by mass of bisphenol A (11.8 ÷ 100 × 600 g = 70.8 g, decomposition rate of polycarbonate resin: 70.8 g ÷ 228 g / mol ÷ 0.315 mol × 100 = 98.6 mol%).

[0353] To the resulting reaction liquid, 600 g of toluene was added, and then 35% by mass hydrochloric acid was added until the pH of the aqueous phase reached 8.6, resulting in the generation of carbon dioxide gas. Thereafter, stirring was stopped to separate the oil and water, and the aqueous phase was extracted from the flask to obtain an organic phase 1. 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, and while monitoring the amount of distillate, the internal temperature was gradually increased to 180°C, and the internal pressure was gradually reduced from normal pressure to 10 kPa to distill off water, toluene, and phenol. Thereafter, the pressure inside 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 demineralized water to obtain an organic phase 3.

[0354] The obtained organic phase 3 was cooled to 20°C to obtain a slurry, which was then filtered to obtain a cake. The resulting 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.

[0355] [Example 10-5] Example 7-1 was repeated except that the bisphenol A obtained in Example 1-1 was replaced with the bisphenol A obtained in Example 10-4. The viscosity average molecular weight (Mv) of the resulting recycled polycarbonate resin was 26,500.

[0356] [Example 11] A 1 L four-neck flask equipped with a thermometer, stirrer, and condenser was charged with 46 g of bisphenol A obtained in Example 1-1, 259 g of epichlorohydrin, 100 g of isopropanol, and 36 g of water. The mixture was heated to 40°C and uniformly dissolved, followed by dropwise addition of 38 g of a 48.5% by mass aqueous sodium hydroxide solution over 90 minutes. Simultaneously with the dropwise addition, the temperature was raised from 40°C to 65°C over 90 minutes. The reaction was then completed by holding the mixture at 65°C for 30 minutes. The reaction mixture was then transferred to a 1 L separatory funnel, 69 g 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 extracted from the separated oil and aqueous phases, and by-product salts and excess sodium hydroxide were removed. The epichlorohydrin was then completely removed under reduced pressure at 150°C. 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 mass% aqueous solution of sodium hydroxide was added and reacted for 60 minutes. After that, 57 g of methyl isobutyl ketone was added, and the mixture was washed four times with 200 g of water. Thereafter, methyl isobutyl ketone was completely removed under reduced pressure at 150°C to obtain the epoxy resin of Example 11. The epoxy equivalent of the obtained epoxy resin was measured in accordance with JIS K7236 (2009) and was found to be 175 g / equivalent.

[0357] [Reference example 11c] The same procedure as in Example 11 was carried out except that bisphenol A (manufactured by Mitsubishi Chemical Corporation) was used instead of the bisphenol A obtained in Example 1-1, to obtain an epoxy resin of Reference Example 11c. The epoxy equivalent of the obtained epoxy resin was measured in accordance with JIS K7236 (2009) and was found to be 173 g / equivalent.

[0358] (Evaluation of epoxy resin composition, cured epoxy resin, and cured physical properties) [Example 12] The epoxy resin of Example 11, a curing agent (manufactured by New Japan Chemical Co., Ltd., product name: Rikacid MH-700), and a curing catalyst (manufactured by Shikoku Chemicals Corporation, product name: Curesol 2E4MZ) were weighed out in the proportions shown in Table 10. The mixture was then stirred at room temperature until homogeneous, to obtain an epoxy resin composition.

[0359] Two glass plates with release PET films attached were prepared, and the distance between the glass plates was adjusted to 3 mm with both release PET films facing inward to prepare a mold. An epoxy resin composition was poured into this mold and heated at 100°C for 3 hours and then at 140°C for 3 hours to obtain a cured epoxy resin product.

[0360] The resulting cured product was cut into a cylindrical shape with a diameter of 1 cm and a thickness of 3 mm to obtain test specimens. The test specimens were measured for their second linear expansion coefficients α1 and α2 using a thermomechanical analyzer (TMA: TMA / SS6100 manufactured by Seiko Instruments Inc.) in compression mode, with a first temperature increase of 5°C / min (from 30°C to 200°C), a first temperature decrease of 10°C / min (from 200°C to 30°C), and a second temperature increase of 5°C / min from 30°C to 200°C.

[0361] [Reference example 12c] The epoxy resin of Reference Example 11, a curing agent (manufactured by New Japan Chemical Co., Ltd., product name: Rikacid MH-700), and a curing catalyst (manufactured by Shikoku Chemicals Corporation, product name: Curesol 2E4MZ) were weighed out in the proportions shown in Table 10. The mixture was then stirred at room temperature until homogeneous, to obtain an epoxy resin composition. The obtained epoxy resin composition was cured in the same manner as in Example 12, and the obtained cured epoxy resin was evaluated to determine the linear expansion coefficients α1 and α2.

[0362] [Table 10]

[0363] [Evaluation of results] Table 10 shows that the cured epoxy resin product of Example 12 has a lower linear expansion coefficient and is more excellent in heat crack resistance than the cured epoxy resin product of Reference Example 12c.

[0364] [Reference Example 13c] Tetraphenoxytitanium was synthesized and used according to the following procedure. A 500 mL three-neck flask equipped with a receiver and a distillation tube was charged with 200 g (2.1 mol) of phenol and 100 mL of toluene, and the flask was purged with nitrogen. The flask was immersed in a 100°C oil bath to obtain a homogeneous solution. 57 g (0.2 mol) of tetraisopropyl titanium was added to the solution. The internal temperature of the flask bottom was maintained at 100°C, and the distillation of the resulting i-propyl alcohol began. The internal temperature was then gradually increased to 116°C, and 80 mL of a distillate, a mixture of i-propyl alcohol and toluene, was distilled off. 50 mL of hexane was added to the resulting bottoms, and the mixture was cooled to room temperature to allow crystallization. The precipitated red crystals were collected 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 50 Torr to obtain 60 g (0.1 mol) of tetraphenoxy titanium.

[0365] [Example 13] 13-1: Synthesis of dimethyl carbonate The synthesis of dimethyl carbonate from carbon dioxide was carried out according to the non-patent document ChemSusChem, 2013, Vol. 6, pp. 1341-1344.

[0366] A 200 mL autoclave equipped with an induction stirrer, a pressure gauge, and a thermometer was charged with 0.4 g of cerium oxide previously calcined at 600°C, 10.4 g of cyanopyridine, and 1.6 g of methanol (1.6 g ÷ 32 g / mol = 50 mmol). The carbon dioxide obtained in Example 1-1 was then introduced into the autoclave using a compressor. After three air exchanges, the internal pressure of the autoclave was adjusted to 5 MPa. The autoclave was then placed in an electric furnace and reacted for 12 hours at an internal temperature of 120°C. After the reaction, the autoclave was immersed in ice water to return the internal pressure to normal pressure. The resulting reaction solution was filtered to remove the cerium oxide, yielding 12.6 g of a mixed solution.

[0367] A portion of the resulting mixture was analyzed by gas chromatography, and it was found that the content of 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%.

[0368] The above operation was repeated several times to obtain 200 g of a mixed liquid. The obtained mixed liquid was placed in a 1 L eggplant-shaped flask and then placed in an evaporator equipped with a water bath to remove the initial fraction, obtaining 31 g of a main fraction. A portion of the obtained main fraction was analyzed by gas chromatography, and the purity of dimethyl carbonate was found to be 97% by mass.

[0369] 13-2: Synthesis of diphenyl carbonate A flask equipped with a distillation tube and a stirring blade was charged with 31 g of the main fraction (30 g of dimethyl carbonate), 40 g of reagent dimethyl carbonate (total dimethyl carbonate 70 g, 0.78 mol), 500 g of phenol (5.32 mol), and 5 g of tetraphenoxytitanium. The produced methanol was distilled off together with the dimethyl carbonate under normal pressure. After the distillation stopped, the pressure was reduced to 1 kPa, and the temperature was gradually increased to 185°C, allowing the reaction to proceed while the dimethyl carbonate was distilled off. The oil bath was then set to 210°C, yielding 11 g of diphenyl carbonate.

[0370] 13-3: Synthesis of recycled polycarbonate resin A 45 mL glass reactor equipped with a stirrer and a distillation tube was charged with 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 aqueous cesium carbonate solution. The pressure in the glass reactor was reduced to approximately 100 Pa, and then the pressure was returned to atmospheric pressure with nitrogen. This operation was repeated three times to replace the inside of the reactor with nitrogen. The reactor was then immersed in an oil bath at 220°C to dissolve the contents.

[0371] The stirrer rotation speed was set to 100 revolutions per minute, and the pressure inside the reaction vessel was reduced from 101.3 kPa to 13.3 kPa absolute pressure over 40 minutes while distilling off phenol, which was a by-product of the oligomerization reaction of bisphenol A and diphenyl carbonate inside the reaction vessel. Subsequently, the pressure inside the reaction vessel was maintained at 13.3 kPa, and the transesterification reaction was carried out for 80 minutes while further distilling off phenol. Thereafter, the temperature outside the reactor was raised to 290°C, and the pressure inside the reactor was reduced from 13.3 kPa to 399 Pa absolute over 40 minutes, and the distilled phenol was removed from the system. Thereafter, the absolute pressure in the reaction vessel was reduced to 30 Pa, and the polycondensation reaction was carried out. The polycondensation reaction was terminated when the agitator in the reaction vessel reached a predetermined agitation power. The time from raising the temperature to 290°C to completing the polymerization was 120 minutes.

[0372] Next, the reactor was restored to an absolute pressure of 101.3 kPa with nitrogen, and then the pressure was increased to a gauge pressure of 0.2 MPa, and the polycarbonate resin was extracted from the reactor to obtain a polycarbonate resin. The viscosity average molecular weight (Mv) of the obtained polycarbonate resin was 24,800. [Industrial Applicability]

[0373] According to the method for producing bisphenol of the present invention, bisphenol can be obtained from waste plastics and the like by utilizing chemical recycling. Furthermore, this can be used to produce polycarbonate resin again, which is industrially useful. [Explanation of symbols]

[0374] 1. Diphenyl carbonate manufacturing plant 2. Hydrogen chloride recovery plant 3. Carbonyl chloride manufacturing plant 10 DPC reactor 11 Dehydrochlorination tower 12 Mixing tank 13 Neutralization tank 14 Wash tank 15, 16 Distillation tower 20 Activated carbon tower 21 Absorption tower 22, 24, 32 Tanks 23 Dissipation Tower 30 CDC reactors 31 Flocculator 33 Evaporator 34 Elimination tower 100, 102, 103 Decomposition tank G10, G12, G20 Hydrogen chloride gas G30 Crude carbonyl chloride gas G31 Unliquefied gas G32 Waste Gas G13 Diphenyl carbonate L10 Reaction solution containing diphenyl carbonate L11 Reaction solution after dehydrochlorination treatment L12, L31 Sodium hydroxide solution L13, L16 oil phase L14 Water phase (neutralized wastewater) L15, L20 water L17 Water phase L21, L24, L26 Dilute hydrochloric acid L23 Concentrated hydrochloric acid L25 Hydrochloric acid wastewater L30 Carbonyl chloride L32 Sodium hydroxide waste liquid L100, L102, L103 Solutions containing bisphenol A CDC, G1 Carbonyl chloride gas CO Carbon monoxide gas CL2 chlorine gas H2O Water PC Polycarbonate Resin PL Phenol PRD Pyridine acid acid base

Claims

1. Polycarbonate resin, A method for producing bisphenols by decomposing an aromatic monoalcohol in the presence of water and a catalyst.

2. 2. The method for producing bisphenol according to claim 1, wherein the catalyst is any one selected from the group consisting of alkali metal hydroxides, alkali metal carbonates, alkylamines, nitrogen-containing heterocyclic compounds, and acids.

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

4. The method for producing bisphenol according to claim 2, wherein the alkylamine is represented by the following formula (I): 【Chemistry 1】 In the formula, R A represents an alkyl group having 1 to 3 carbon atoms, and R B ~R C each independently represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.

5. The method for producing bisphenol according to claim 2 or 4, wherein the alkylamine is a tertiary amine.

6. 3. The method for producing bisphenol according to claim 2, wherein the acid is any one selected from the group consisting of hydrochloric acid, sulfuric acid, phosphoric acid, and sulfonic acid.

7. the catalyst comprises a nitrogen-containing heterocyclic compound; 2. The method for producing bisphenol according to claim 1, wherein the polycarbonate resin is decomposed in the coexistence of an alkali metal chloride in addition to the aromatic monoalcohol, the water, and the catalyst.

8. 8. The method for producing bisphenol according to claim 2 or 7, wherein the nitrogen-containing heterocyclic compound is a pyridine.

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

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

11. 11. The method for producing bisphenol according to claim 1, wherein the polycarbonate resin is decomposed in a slurry reaction liquid containing the polycarbonate resin, the aromatic monoalcohol, the water, and the catalyst.

12. The method for producing bisphenol according to any one of claims 1 to 11, wherein a mass ratio of the water to the aromatic monoalcohol is 0.001 or more and 10 or less.

13. the catalyst comprises hydrochloric acid; 2. The method for producing bisphenol according to claim 1, wherein the polycarbonate resin is decomposed in the coexistence of a bromophenol in addition to the aromatic monoalcohol, the water, and the catalyst.

14. the catalyst comprises sodium hydroxide; 2. The method for producing bisphenol according to claim 1, wherein the polycarbonate resin is decomposed in the coexistence of sodium chloride and / or carbon tetrachloride in addition to the aromatic monoalcohol, the water, and the catalyst.

15. 15. The method for producing bisphenol according to claim 1, wherein the aromatic monoalcohol is any one selected from the group consisting of phenol, cresol, and xylenol.

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

17. 8. The method for producing bisphenol according to claim 1 or 7, wherein neutralization wastewater removed in step (b1) of producing diaryl carbonate by a method comprising the following steps (a1), (b1), (b2), and (b3) is used for decomposing the polycarbonate resin: Step (a1): A step of reacting carbonyl chloride with an aromatic monoalcohol in the presence of a nitrogen-containing heterocyclic compound to obtain a reaction solution containing a diaryl carbonate. Step (b1): A step of neutralizing the reaction solution containing the diaryl carbonate obtained in step (a1) with an aqueous alkali metal hydroxide solution, separating the mixture into an oil phase containing the diaryl carbonate and an aqueous phase containing a nitrogen-containing heterocyclic compound and an alkali metal chloride, and then 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 alkali metal chloride in step (b1) is sodium chloride, 18. The method for producing bisphenol according to claim 17, wherein the aqueous alkali metal hydroxide solution in step (b1) is an aqueous sodium hydroxide solution.

19. 14. The method for producing bisphenols according to claim 1 or 13, wherein in the production of diaryl carbonate and recovery of by-produced hydrogen chloride, which comprises the following steps (a1), (c1), (c2), and (c3), hydrochloric acid wastewater removed in step (c3) is used for decomposing the polycarbonate resin: Step (a1): A step of reacting carbonyl chloride with an aromatic monoalcohol in the presence of a nitrogen-containing heterocyclic compound to obtain a reaction solution containing a diaryl carbonate. Step (c1): A step of supplying the hydrogen chloride by-produced in step (a1) to an absorption tower and absorbing it in water or dilute hydrochloric acid to obtain concentrated hydrochloric acid. Step (c2): A step of distilling concentrated hydrochloric acid in a stripper column, recovering hydrogen chloride gas from the top of the column, and recovering hydrochloric acid from the bottom of the column. Step (c3): A step of removing a part of the hydrochloric acid recovered from the bottom of the column to the outside of the system as hydrochloric acid waste water, and circulating the remaining hydrochloric acid to the absorption column of step (c1).

20. The method for producing bisphenol according to claim 1 or 14, wherein in the production of carbonyl chloride and the treatment of unliquefied gas, which comprises the following steps (d1) to (d4), sodium hydroxide wastewater removed in step (d4) is used for decomposing the polycarbonate resin: Step (d1): A step of obtaining carbonyl chloride gas from chlorine and carbon monoxide Step (d2): A step of cooling the carbonyl chloride gas obtained in step (d1) to obtain liquefied carbonyl chloride. Step (d3): A step of contacting the circulating aqueous sodium hydroxide solution with the unliquefied gas that was not liquefied in step (d2) to decompose carbonyl chloride in the unliquefied gas, followed by discharging the decomposed carbonyl chloride. Step (d4): A step of removing a portion of the circulating aqueous sodium hydroxide solution as sodium hydroxide wastewater.

21. A method for producing a recycled polycarbonate resin, comprising: a step of obtaining bisphenol by the method for producing bisphenol according to any one of claims 1 to 20; and a step of producing a recycled polycarbonate resin using a bisphenol raw material containing the obtained bisphenol.

22. A method for producing carbon dioxide, comprising recovering carbon dioxide produced by the method for producing bisphenol according to any one of claims 1 to 20.

23. A method for producing a carbonic acid diester, comprising: obtaining carbon dioxide by the method for producing carbon dioxide according to claim 22; and producing a carbonic acid diester using the obtained carbon dioxide.

24. The method for producing a carbonic acid diester according to claim 23, wherein in the step of producing the carbonic acid diester, the carbon dioxide containing the carbon dioxide obtained in the step of obtaining carbon dioxide is reacted with an aliphatic monoalcohol to obtain the carbonic acid diester.

25. The method for producing a carbonate diester according to claim 23, wherein in the step of producing a carbonate diester, carbon monoxide is obtained from the carbon dioxide containing the carbon dioxide obtained in the step of obtaining carbon dioxide and coke, the obtained carbon monoxide is reacted with chlorine to obtain carbonyl chloride, and the obtained carbonyl chloride is reacted with an aromatic monoalcohol to obtain the carbonate diester.

26. 26. A method for producing a recycled polycarbonate resin, comprising: obtaining a carbonic acid diester by the method for producing a carbonic acid diester according to any one of claims 23 to 25; and producing a recycled polycarbonate resin using the obtained carbonic acid diester raw material containing the carbonic acid diester.

27. 21. A method for producing an epoxy resin, comprising the steps of: obtaining bisphenol by the method for producing bisphenol according to claim 1; and producing an epoxy resin using the obtained bisphenol.

28. 28. The method for producing an epoxy resin according to claim 27, further comprising a step of reacting the epoxy resin obtained in the step of producing an epoxy resin with a polyvalent hydroxy compound raw material.

29. 29. A method for producing a cured epoxy resin product, comprising: 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 obtained epoxy resin and a curing agent to obtain a cured epoxy resin product.

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