Method for decomposing polycarbonate resin, method for producing bisphenol, method for producing dialkyl carbonate, method for producing alkyl aryl carbonate, method for producing diaryl carbonate

Abstract

Provided is a method for decomposing a polycarbonate resin with high reactivity even under mild conditions with a small environmental burden. Also provided is a method for producing an alkyl aryl carbonate that can efficiently obtain a dialkyl aryl carbonate by decomposing a polycarbonate resin even under mild conditions with a small environmental burden. A method for decomposing a polycarbonate resin, wherein the polycarbonate resin is decomposed in a reaction liquid in slurry form containing the polycarbonate resin, an aromatic monohydric alcohol, an aliphatic monohydric alcohol, and a catalyst. Also provided is a method for producing an alkyl aryl carbonate, which has a step for decomposing a polycarbonate resin, wherein the polycarbonate resin is decomposed in the presence of an aromatic monohydric alcohol, an aliphatic monohydric alcohol, and a catalyst, and a step for recovering an alkyl aryl carbonate, wherein an alkyl aryl carbonate produced by the decomposition of the polycarbonate is recovered.

Description

Technical Field

[0001] This invention relates to a method for decomposing polycarbonate resins. Furthermore, it relates to a method for manufacturing bisphenols, dialkyl carbonates, and alkyl aryl carbonates using the decomposition of polycarbonate resins. Additionally, it relates to a method for manufacturing diaryl carbonates using dialkyl carbonates obtained by the aforementioned method or alkyl aryl carbonates obtained by the aforementioned method. Moreover, it relates to a method for manufacturing recycled polycarbonate resins using bisphenols obtained by the aforementioned method or diaryl carbonates obtained by the aforementioned method. Finally, this invention relates to a method for manufacturing epoxy resins and a method for manufacturing cured epoxy resins. Background Technology

[0002] Plastics are produced in large quantities not only in Japan but also worldwide due to their simplicity, durability, and low cost. Most of this plastic is intended for single use, and therefore, it sometimes ends up in the environment without proper treatment. Specifically, plastic waste flows from rivers into the ocean, where it deteriorates due to waves and ultraviolet radiation, shrinking to less than 5mm. This tiny plastic waste is called microplastics. These microplastics can be ingested by animals and fish. Thus, plastic waste has a significant impact on ecosystems and has recently been recognized as a global problem related to marine plastic pollution.

[0003] Polycarbonate resins are used in a wide range of fields due to their transparency, mechanical properties, flame retardancy, dimensional stability, and electrical properties, and this polycarbonate resin is no exception.

[0004] One method for recycling polycarbonate resin is chemical recycling, which involves chemically decomposing the polycarbonate resin back into bisphenol for reuse. Another known method for decomposing polycarbonate resin is alcoholysis.

[0005] For example, Patent Document 1 discloses a method in which aromatic polycarbonate dissolved in monohydroxy compounds other than methanol is subjected to contact transesterification with methanol in a distillation column, thereby continuously ring-opening aromatic polycarbonate into dihydroxy compounds and dimethyl carbonate.

[0006] In addition, Patent Document 2 discloses a method for recovering useful materials from waste plastics, which includes the following steps: adding a specific tertiary amine as a catalyst to a solution containing waste plastics and monohydric alcohols or monohydric phenols to chemically decompose the aforementioned polycarbonate resin in the aforementioned waste plastics; and recovering the decomposition products as useful materials.

[0007] Patent document 3 discloses a method for obtaining aromatic dihydroxy compounds from waste aromatic polycarbonate by decomposing it through transesterification in the presence of alcohols with 1 to 4 carbon atoms, chlorinated organic solvents, and metal hydroxides.

[0008] Existing technical documents

[0009] Patent documents

[0010] Patent Document 1: Japanese Patent Application Publication No. 6-340591

[0011] Patent Document 2: Japanese Patent Application Publication No. 2004-51620

[0012] Patent Document 3: Japanese Patent Application Publication No. 2006-22029 Summary of the Invention

[0013] The problem the invention aims to solve

[0014] In the alcoholysis decomposition method of polycarbonate resin, aliphatic monohydric alcohols are commonly used. However, aliphatic monohydric alcohols with fewer carbon atoms have low boiling points, resulting in high-pressure conditions when the reaction is carried out at high decomposition temperatures. Therefore, pressure-resistant containers are required.

[0015] In addition, according to Example 1 of Patent Document 1, polycarbonate resin is dissolved in phenol at 150°C and decomposed by convection contact with vapor containing methanol and dimethyl carbonate. However, in order to carry out this at atmospheric pressure, there are problems such as complex control of the device or difficulty in controlling the decomposition of polycarbonate resin.

[0016] Furthermore, in the method of Patent Document 2, since polycarbonate resin is poorly soluble in methanol, an amine is used as both a solvent and a catalyst. However, when the amount of amine is small, there are problems such as low reactivity and prolonged reaction time.

[0017] In decomposition methods that use methanol to decompose polycarbonate resin near room temperature, chlorinated hydrocarbon solvents are used to dissolve the polycarbonate. For example, according to Example 1 of Patent Document 3, dichloromethane is used as the solvent. Chlorinated hydrocarbon solvents such as dichloromethane are chemically stable and therefore flame-retardant compounds. Therefore, if waste disposal at high temperatures is not properly handled, there is a risk of dioxin generation.

[0018] The aforementioned methods for decomposing aliphatic monohydric alcohols on any polycarbonate resin require high temperature and high pressure conditions, or the reactivity is insufficient, or they require solvents that are harmful to the environment, thus requiring further improvement.

[0019] The present invention was made in view of this situation, and its object is to provide a method for decomposing polycarbonate resin, which can decompose polycarbonate resin with high reactivity even under mild and environmentally unfriendly conditions.

[0020] In addition, the object of the present invention is to provide a method for manufacturing bisphenol using a polycarbonate resin decomposition method.

[0021] Furthermore, an object of the present invention is to provide a method for manufacturing a recycled polycarbonate resin using bisphenol obtained by the aforementioned bisphenol manufacturing method.

[0022] Furthermore, the object of the present invention is to provide a method for manufacturing an epoxy resin using the aforementioned bisphenol obtained by the aforementioned bisphenol manufacturing method, and a method for manufacturing an epoxy resin cured product using the obtained epoxy resin.

[0023] Furthermore, an object of the present invention is to provide a method for manufacturing dialkyl carbonate using a polycarbonate resin decomposition method, and a method for manufacturing diaryl carbonate using the dialkyl carbonate obtained by the aforementioned method. An additional object is to provide a method for manufacturing recycled polycarbonate resin using the diaryl carbonate obtained by the aforementioned method.

[0024] On the other hand, a known method for producing dialkyl carbonate using dialkyl carbonate involves reacting a dialkyl carbonate with an aromatic monohydric alcohol to obtain an alkylaryl carbonate, followed by a disproportionation reaction of the alkylaryl carbonate to obtain a diaryl carbonate. However, the reaction of dialkyl carbonate with an aromatic monohydric alcohol to obtain an alkylaryl carbonate is an equilibrium reaction. This reaction is slow, and the equilibrium is extremely biased towards the reactant system. Therefore, a method for efficiently obtaining alkylaryl carbonate is required.

[0025] Therefore, an object of the present invention is to provide a method for manufacturing alkyl aryl carbonates that can efficiently yield alkyl aryl carbonates by decomposing polycarbonate resins even under mild and environmentally unfriendly conditions. Another object is to provide a method for manufacturing diaryl carbonates using alkyl aryl carbonates obtained by the aforementioned method. Furthermore, an object is to provide a method for manufacturing recycled polycarbonate resins using diaryl carbonates obtained by the aforementioned method.

[0026] Solution for solving the problem

[0027] In order to solve the above-mentioned problems, the inventors conducted in-depth research and discovered a decomposition method for polycarbonate resin by using a combination of aromatic monohydric alcohols and aliphatic monohydric alcohols. Furthermore, it was found that this decomposition method can be used in the manufacture of bisphenols, as well as dialkyl carbonates and / or alkyl aryl carbonates.

[0028] That is, the present invention relates to the following technical solutions.

[0029] <1> A method for decomposing polycarbonate resin, wherein the polycarbonate resin is decomposed in a slurry-like reaction solution comprising polycarbonate resin, aromatic monohydric alcohol, aliphatic monohydric alcohol and a catalyst.

[0030] <2> A method for decomposing polycarbonate resin includes: a preparation step of preparing a slurry-like reaction solution comprising polycarbonate resin, an aromatic monohydric alcohol, an aliphatic monohydric alcohol, and a catalyst; and a decomposition reaction step of decomposing the polycarbonate resin in the slurry-like reaction solution prepared in the aforementioned preparation step.

[0031] <3> According to the foregoing <1> or <2> The method for decomposing polycarbonate resin, wherein the catalyst is selected from any one of the group consisting of alkali metal hydroxides, alkali metal carbonates, alkylamines and acids.

[0032] <4> According to the foregoing <3> The method for decomposing the polycarbonate resin, wherein the aforementioned alkylamine is represented by the following formula (I).

[0033]

[0034] In the formula, R A R represents an alkyl group having 1 to 3 carbon atoms. B ~R C Each can be independently represented by a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.

[0035] <5> According to the foregoing <3> The method for decomposing the polycarbonate resin, wherein the aforementioned alkylamine is a tertiary amine.

[0036] <6> According to the foregoing <3> ~ <5> The method for decomposing polycarbonate resin according to any one of the above methods, wherein the molar ratio of the alkylamine to the repeating unit 1 mole of the polycarbonate resin in the aforementioned slurry-like reaction solution is 4.5 or less.

[0037] <7> According to the foregoing <3> The method for decomposing the polycarbonate resin, wherein the aforementioned alkali metal hydroxide is sodium hydroxide or potassium hydroxide.

[0038] <8> According to the foregoing <3> The method for decomposing the polycarbonate resin, wherein the aforementioned acid is selected from any one of the group consisting of sulfuric acid, phosphoric acid, and sulfonic acid.

[0039] <9> According to the foregoing <1> ~ <8> The method for decomposing the polycarbonate resin according to any one of the following, wherein the aforementioned aromatic monohydric alcohol is selected from any group consisting of phenol, cresol and xylenol.

[0040] <10> According to the foregoing <1> ~ <9> The method for decomposing polycarbonate resin according to any one of the following, wherein the aforementioned aliphatic monohydric alcohol is selected from the group consisting of methanol, ethanol and n-butanol.

[0041] <11> According to the foregoing <1> ~ <10> The method for decomposing the polycarbonate resin according to any one of the above methods, wherein the molar ratio of the aforementioned aliphatic monohydric alcohol to the aforementioned aromatic monohydric alcohol is 0.7 or less.

[0042] <12> According to the foregoing <1> ~ <11> The method for decomposing the polycarbonate resin according to any one of the above methods, wherein the reaction temperature for decomposing the aforementioned polycarbonate resin is below 120°C.

[0043] <13> A method for manufacturing bisphenol, comprising: a decomposition step, using the aforementioned <1> ~ <12> The method for decomposing polycarbonate resin according to any one of the above methods, wherein the polycarbonate resin is decomposed; and the bisphenol recovery step, wherein the bisphenol generated by the aforementioned decomposition of the polycarbonate resin is recovered.

[0044] <14> According to the foregoing <13> The method for manufacturing bisphenol, wherein the aforementioned bisphenol is 2,2-bis(4-hydroxyphenyl)propane.

[0045] <15> A method for manufacturing a dialkyl carbonate, comprising: a decomposition step, using the aforementioned... <1> ~ <12> The method for decomposing polycarbonate resin according to any one of the above methods decomposes the polycarbonate resin; and the dialkyl carbonate recovery step recovers the dialkyl carbonate generated by the decomposition of the aforementioned polycarbonate resin.

[0046] <16> According to the foregoing <15> In the method for manufacturing dialkyl carbonate, the molar ratio of the aliphatic monohydric alcohol to the repeating unit 1 of the polycarbonate resin in the aforementioned slurry-like reaction solution is 2.0 or more and 6.0 or less.

[0047] <17> A method for manufacturing an alkyl aryl carbonate includes: a polycarbonate resin decomposition step, wherein the polycarbonate resin is decomposed in the presence of an aromatic monohydric alcohol, an aliphatic monohydric alcohol and a catalyst; and an alkyl aryl carbonate recovery step, wherein the alkyl aryl carbonate generated by the aforementioned decomposition of the polycarbonate is recovered.

[0048] <18> A method for manufacturing an alkyl aryl carbonate, comprising: a decomposition step, using the aforementioned... <1> ~ <12> The method for decomposing the polycarbonate resin according to any one of the above methods, wherein the polycarbonate resin is decomposed; and the alkyl aryl carbonate recovery step, wherein the alkyl aryl carbonate generated by the decomposition of the aforementioned polycarbonate resin is recovered.

[0049] <19> According to the foregoing <17> or <18> The method for manufacturing the alkyl aryl carbonate, wherein the aforementioned aromatic monohydric alcohol is phenol, and the aforementioned alkyl aryl carbonate is alkyl phenyl carbonate.

[0050] <20> According to the foregoing <17> ~ <19> The method for manufacturing the alkyl aryl carbonate ester according to any one of the above methods, wherein the molar ratio of the aforementioned aliphatic monohydric alcohol to the repeating unit 1 mole of the aforementioned polycarbonate resin is 0.1 or more and less than 2.0.

[0051] <21> A method for producing a diaryl carbonate, wherein the aforementioned... <15> or <16> The dialkyl carbonate obtained by the aforementioned method is used to manufacture diaryl carbonate.

[0052] <22> A method for producing a diaryl carbonate, wherein the aforementioned... <17> ~ <19> The alkyl aryl carbonate ester obtained by any one of the methods for producing alkyl aryl carbonates is used to produce diaryl carbonates.

[0053] <23> A method for manufacturing recycled polycarbonate resin, wherein a mixture comprising the aforementioned... <13> or <14> The bisphenol raw material obtained by the aforementioned bisphenol manufacturing method is used to manufacture recycled polycarbonate resin.

[0054] <24> A method for manufacturing recycled polycarbonate resin, wherein a mixture comprising the aforementioned... <21> or <22> The diaryl carbonate raw material obtained by the method for manufacturing diaryl carbonate is used to manufacture recycled polycarbonate resin.

[0055] <25> A method for manufacturing recycled epoxy resin, wherein the aforementioned... <13> or <14> The bisphenol obtained by the aforementioned method is used to manufacture recycled epoxy resin.

[0056] <26> According to the foregoing <25> The method for manufacturing the regenerated epoxy resin includes further reacting the aforementioned regenerated epoxy resin with a polyhydroxy compound raw material.

[0057] <27> A method for manufacturing a recycled epoxy resin cured product, wherein the process comprises the aforementioned steps... <25> or <26> The recycled epoxy resin and the recycled epoxy resin composition obtained by the aforementioned method of manufacturing recycled epoxy resin are cured to obtain a cured recycled epoxy resin product.

[0058] The effects of the invention

[0059] According to the present invention, a method for decomposing polycarbonate resins with high reactivity is provided, which can decompose polycarbonate resins even under mild and environmentally unfriendly conditions.

[0060] In addition, according to the present invention, a method for manufacturing bisphenol using a polycarbonate resin decomposition method is provided.

[0061] Furthermore, according to the present invention, a method for manufacturing a recycled polycarbonate resin using bisphenol obtained by the aforementioned bisphenol manufacturing method is provided.

[0062] Furthermore, according to the present invention, a method for manufacturing an epoxy resin using the aforementioned bisphenol obtained by the aforementioned bisphenol manufacturing method, and a method for manufacturing an epoxy resin cured product using the obtained epoxy resin are provided.

[0063] Furthermore, according to the present invention, a method for decomposing polycarbonate resin, a method for manufacturing dialkyl carbonate to produce dialkyl carbonate, and a method for manufacturing diaryl carbonate using dialkyl carbonate obtained by the aforementioned method for manufacturing dialkyl carbonate are provided. Furthermore, a method for manufacturing recycled polycarbonate resin using diaryl carbonate obtained by the aforementioned method for manufacturing diaryl carbonate is provided.

[0064] Furthermore, according to the present invention, a method for manufacturing alkyl aryl carbonates is provided, which can efficiently obtain alkyl aryl carbonates by decomposing polycarbonate resins even under mild and environmentally unfriendly conditions. Additionally, a method for manufacturing diaryl carbonates using alkyl aryl carbonates obtained by the aforementioned method is provided. Furthermore, a method for manufacturing recycled polycarbonate resins using diaryl carbonates obtained by the aforementioned method is provided. Attached Figure Description

[0065] Figure 1 This is a flowchart of the decomposition method of the present invention.

[0066] Figure 2 A flowchart illustrating an example of a method for manufacturing bisphenol according to the present invention.

[0067] Figure 3 A flowchart illustrating an example of a method for manufacturing bisphenol according to the present invention.

[0068] Figure 4 A flowchart illustrating an example of a method for manufacturing bisphenol according to the present invention.

[0069] Figure 5 For use in Figure 2 The flowchart (A3) explains the process.

[0070] Figure 6 For use in Figure 2 The flowchart (A3) explains the process.

[0071] Figure 7 For use in Figure 3 The flowchart describes the process (B2).

[0072] Figure 8 For use in Figure 3 The flowchart describes the process (B2).

[0073] Figure 9 A flowchart illustrating an example of a method for manufacturing dialkyl carbonates according to the present invention.

[0074] Figure 10 A flowchart illustrating an example of a method for manufacturing dialkyl carbonates according to the present invention.

[0075] Figure 11 A flowchart illustrating an example of a method for manufacturing the alkyl aryl carbonate of the present invention.

[0076] Figure 12 A flowchart illustrating an example of a method for manufacturing the alkyl aryl carbonate of the present invention. Detailed Implementation

[0077] The embodiments of the present invention will now be described in detail. However, the description of the constituent elements described below is only 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 its gist. It should be noted that when the expression "~" is used in this specification, it is used to describe the numerical values ​​or physical property values ​​that precede or follow it.

[0078] <Methods for decomposing polycarbonate resin>

[0079] This invention relates to a method for decomposing polycarbonate resin (hereinafter sometimes referred to as "the decomposition method of this invention"), which includes a decomposition step of decomposing the aforementioned polycarbonate resin in a slurry-like reaction solution comprising polycarbonate resin, aromatic monohydric alcohol, aliphatic monohydric alcohol and a catalyst.

[0080] In addition, the decomposition method of the present invention is as follows: Figure 1 As shown, the following method for decomposing polycarbonate resin can be used, comprising: a preparation step (S1) for preparing a slurry-like reaction solution containing polycarbonate resin, an aromatic monohydric alcohol, an aliphatic monohydric alcohol and a catalyst; and a decomposition reaction step (S2) for decomposing the aforementioned polycarbonate resin in the slurry-like reaction solution prepared in the preparation step (S1).

[0081] The decomposition method of this invention decomposes polycarbonate resin in the presence of aromatic monohydric alcohols, aliphatic monohydric alcohols, and a catalyst. Aromatic and aliphatic monohydric alcohols are considered poor solvents for polycarbonate resins, and mixing these solvents complicates solvent recovery and separation. Therefore, there has been no advantage to using these solvents in combination. However, surprisingly, the inventors have discovered that polycarbonate resin can be decomposed even under mild conditions at atmospheric pressure by reacting in a mixed solvent containing aromatic and aliphatic monohydric alcohols in the presence of a catalyst. Furthermore, it has been found that even without using solvents with high polycarbonate resin solubility, such as halogen solvents, to completely dissolve the polycarbonate resin, the decomposition reaction of polycarbonate resin occurs at a high reaction rate by using a combination of aromatic and aliphatic monohydric alcohols.

[0082] It is believed that by using a combination of aromatic and aliphatic monohydric alcohols, both solvent decomposition based on aromatic monohydric alcohols (e.g., phenololysis) and solvent decomposition based on aliphatic monohydric alcohols (e.g., methanololysis) occur within the system, thus making polycarbonate resins readily decompose even under mild conditions.

[0083] In addition, polycarbonate resin is poorly soluble in aromatic monohydric alcohols and aliphatic monohydric alcohols. Therefore, by reacting the polycarbonate resin in a slurry-like reaction solution in which the polycarbonate resin is dispersed in these mixed solvents, only the polycarbonate resin that is soluble in proportion to its solubility participates in the decomposition reaction. This makes it easy to control the reaction and thus allows for the stable decomposition of the polycarbonate resin.

[0084] (Polycarbonate resin)

[0085] The polycarbonate resin used in the decomposition method of the present invention comprises a polymeric composition having carbonate bonds (-OC(=O)-O-). Specifically, the polycarbonate resin used in the decomposition method of the present invention comprises a polymer of general formula (1) containing repeating units derived from bisphenol.

[0086]

[0087] As R 1 ~R 4Substituents can be categorized independently as hydrogen atoms, halogen atoms, alkyl groups, alkoxy groups, aryl groups, etc. Examples include hydrogen atoms, fluorine groups, chloro groups, bromine groups, iodoyl groups, methyl groups, ethyl groups, n-propyl groups, isopropyl groups, n-butyl groups, isobutyl groups, tert-butyl groups, n-pentyl groups, isopentyl groups, n-hexyl groups, n-heptyl groups, n-octyl groups, n-nonyl groups, n-decyl groups, n-undecyl groups, n-dodecyl groups, methoxy groups, ethoxy groups, n-propoxy groups, isopropoxy groups, n-butoxy groups, isobutoxy groups, tert-butoxy groups, n-pentyl groups, isopentyl groups, n-hexyl groups, n-heptyl groups, n-octyl groups, n-nonyl groups, n-decyl groups, n-undecyl groups, n-dodecyl groups, cyclopropyl groups, cyclobutyl groups, cyclopentyl groups, cyclohexyl groups, cycloheptyl groups, cyclooctyl groups, cyclododecyl groups, benzyl groups, phenyl groups, tolyl groups, 2,6-dimethylphenyl groups, etc.

[0088] As R 5 and R 6 Substituents can be categorized independently as hydrogen atoms, alkyl groups, alkoxy groups, aryl groups, etc. Examples include hydrogen atoms, methyl groups, ethyl groups, n-propyl groups, isopropyl groups, n-butyl groups, isobutyl groups, tert-butyl groups, n-pentyl groups, isopentyl groups, n-hexyl groups, n-heptyl groups, n-octyl groups, 2-ethylhexyl groups, n-nonyl groups, n-decyl groups, n-undecyl groups, n-dodecyl groups, methoxy groups, ethoxy groups, n-propoxy groups, isopropoxy groups, n-butoxy groups, isobutoxy groups, tert-butoxy groups, n-pentyloxy groups, isopentyloxy groups, n-hexyloxy groups, n-heptyloxy groups, n-octyloxy groups, n-nonyloxy groups, n-decyloxy groups, n-undecyloxy groups, n-dodecyloxy groups, cyclopropyl groups, cyclobutyl groups, cyclopentyl groups, cyclohexyl groups, cycloheptyl groups, cyclooctyl groups, cyclododecyl groups, benzyl groups, phenyl groups, tolyl groups, 2,6-dimethylphenyl groups, etc.

[0089] R 5 With R 6 Two groups can be bonded or cross-linked to form cycloalkylidenes. Examples include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, 3,3,5-trimethylcyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl, cycloundecyl, cyclododecyl, fluorenylidene, xanthenylidene, and thioxanthenylidene.

[0090] For the decomposition method of the present invention, it is suitable to use R of the above general formula (1). 1 ~R 4 For hydrogen atoms, R 5 R 6 Methyl polycarbonate resin (bisphenol A type polycarbonate resin) is used as raw material.

[0091] In general formula (1), n ​​is not specifically limited, for example, it can be 2 to 1000.

[0092] The polycarbonate resin used as a raw material in this invention can be used not only as a single polycarbonate resin, but also as a composition containing resins other than polycarbonate resin, such as copolymers or polymer alloys. Examples of compositions containing resins other than polycarbonate resin include polycarbonate / polyester copolymers, polycarbonate / polyester alloys, polycarbonate / polyaryl copolymers, and polycarbonate / polyaryl alloys. When using a composition containing resins other than polycarbonate resin, it is suitable to use one that is primarily composed of polycarbonate resin (containing 50% by mass or more of polycarbonate resin in the composition).

[0093] Furthermore, two or more different polycarbonate resins can be mixed and used. It should be noted that polycarbonate resin alone is sometimes simply referred to as polycarbonate.

[0094] From a chemical recycling perspective, polycarbonate resins preferably include those found in waste plastics. Polycarbonate resins are used to process various molded products, such as optical components like headlamps and optical recording media like optical discs. Waste plastics containing polycarbonate resins can be used as scraps, defective products, or used molded products from the molding process of polycarbonate resins into these products.

[0095] Waste plastics can be obtained by washing, crushing, and pulverizing as appropriate. Methods for crushing waste plastics include using jaw crushers or rotary crushers to crush them into coarse pieces (less than 20 cm); using rotary crushers, cone crushers, or mills to crush them into medium pieces (less than 1 cm); and using mills to pulverize them into pieces (less than 1 mm), as long as the pieces are small enough to be fed into the decomposition tank. Additionally, for thin plastics such as CDs and DVDs, shredders can be used to cut them before feeding them into the decomposition tank. Furthermore, components other than polycarbonate resin, such as copolymers, polymer alloys, and the surface and back layers of optical discs, can be removed before use.

[0096] (Aromatic monohydric alcohols)

[0097] One feature of the decomposition method of the present invention is the use of an aromatic monohydric alcohol. An aromatic monohydric alcohol is a compound in which a hydroxyl group is bonded to a carbon atom forming an aromatic ring, preferably any one of phenol, cresol, and xylenol.

[0098] Examples of cresols include o-cresol, m-cresol, p-cresol, and mixtures of one or more isomers thereof. From the viewpoint that they are readily supplied to the decomposition tank if they are liquid at around 30°C, o-cresol, m-cresol, a mixture of isomers of m-cresol and p-cresol, or a mixture of isomers of o-cresol, m-cresol, and p-cresol are preferred.

[0099] Examples of xylenol include 2,3-xylenol, 2,4-xylenol, 2,5-xylenol, 2,6-xylenol, 3,5-xylenol, 3,4-xylenol, and mixtures of one or more isomers thereof. From the perspective of being industrially available at low cost, 2,5-xylenol is preferred.

[0100] If the amount of aromatic monohydric alcohol used is small relative to the amount of polycarbonate resin used, the amount of solid (polycarbonate resin) relative to liquid will increase, resulting in a higher slurry concentration and a tendency for poor mixing. Therefore, the molar ratio of aromatic monohydric alcohol to 1 mole of repeating unit of polycarbonate resin (i.e., repeating unit shown in the above general formula (1)) ((mass of aromatic monohydric alcohol used [g] / molecular weight of aromatic monohydric alcohol [g / mol]) / (mass of polycarbonate resin used [g] / molecular weight of repeating unit [g / mol])) is preferably 0.01 or more, more preferably 0.03 or more. In addition, if the amount of aromatic monohydric alcohol used is large relative to the amount of polycarbonate resin used, the manufacturing efficiency tends to deteriorate. Therefore, the molar ratio of aromatic monohydric alcohol to 1 mole of repeating unit of polycarbonate resin is preferably 100 or less, more preferably 70 or less, and even more preferably 50 or less.

[0101] (Aliphatic monohydric alcohol)

[0102] One characteristic of the decomposition method of the present invention is the use of an aliphatic monohydric alcohol. An aliphatic monohydric alcohol is a compound with one hydroxyl group bonded to an alkyl group, and is R... 7 OH(R 7 The compound indicated by alkyl group. Examples of aliphatic monohydric alcohols include methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, tert-butanol, n-pentanol, isopentanol, n-hexanol, n-heptanol, n-octanol, n-nonanol, n-decanol, n-undecylol, and n-dodecylol. Preferably, the aliphatic monohydric alcohol is a straight-chain alcohol having 1 to 5 carbon atoms, and more preferably any alcohol selected from the group consisting of methanol, ethanol, and n-butanol.

[0103] If the amount of aliphatic monohydric alcohol used is small relative to the amount of polycarbonate resin used, the polycarbonate resin becomes difficult to decompose or the decomposition rate decreases, thus tending to prolong the decomposition time and degrade efficiency. Therefore, the molar ratio of aliphatic monohydric alcohol to 1 mole of repeating unit of polycarbonate resin ((mass of aliphatic monohydric alcohol used [g] / molecular weight of aliphatic monohydric alcohol [g / mol]) / (mass of polycarbonate resin used [g] / molecular weight of repeating unit [g / mol])) is preferably 0.1 or more, more preferably 0.5 or more, and even more preferably 1.0 or more. Furthermore, if the amount of aliphatic monohydric alcohol used is large relative to the amount of polycarbonate resin used, the manufacturing efficiency tends to degrade. Therefore, the molar ratio of aliphatic monohydric alcohol to 1 mole of repeating unit of polycarbonate resin is preferably 6.0 or less, more preferably 5.5 or less, and even more preferably 5.0 or less.

[0104] Furthermore, as described later, the structure of the carbonyl compound that is a decomposition product can be controlled by adjusting the amount of aliphatic monohydric alcohol. Therefore, the amount of aliphatic monohydric alcohol is preferably controlled according to the desired structure of the carbonyl compound.

[0105] In order to efficiently manufacture dialkyl carbonate, the molar ratio of aliphatic monohydric alcohol to 1 mole of repeating unit of polycarbonate resin is preferably 2.0 or more, more preferably 2.1 or more, and even more preferably 2.2 or more.

[0106] In addition, in order to suppress the formation of dialkyl carbonate and efficiently produce alkyl aryl carbonate, the molar ratio of aliphatic monohydric alcohol to 1 mole of repeating unit of polycarbonate resin is preferably less than 2.0, and can be set to 1.95 or less, 1.9 or less, 1.85 or less, 1.8 or less, etc.

[0107] Furthermore, the molar ratio of the aliphatic monohydric alcohol to the aromatic monohydric alcohol (moles of aliphatic monohydric alcohol / moles of aromatic monohydric alcohol) is preferably 0.01 or more, more preferably 0.05 or more. This molar ratio is also preferably 0.7 or less, more preferably 0.6 or less, more preferably 0.5 or less, and more preferably 0.3 or less. If the molar ratio of the aliphatic monohydric alcohol to the aromatic monohydric alcohol is small, the polycarbonate resin becomes difficult to decompose, or the decomposition rate decreases, thus prolonging the decomposition time. Conversely, if the molar ratio is large, the separation of the aliphatic monohydric alcohol and the dialkyl carbonate becomes complicated in the case of recovering the dialkyl carbonate.

[0108] (catalyst)

[0109] One feature of the decomposition method of the present invention is the use of a catalyst. The catalyst may be any catalyst capable of promoting the decomposition of polycarbonate resin, and is preferably selected from any group consisting of alkali metal hydroxides, alkali metal carbonates, alkylamines, and acids.

[0110] [Alkali metal hydroxides]

[0111] Alkali metal hydroxides are alkali metal ions (M + ) and hydroxide ions (OH) - The salt of ) is a compound represented by MOH (M represents an alkali metal atom). Sodium hydroxide or potassium hydroxide is preferred as the alkali metal hydroxide.

[0112] If the amount of alkali metal hydroxide used is small relative to the amount of polycarbonate resin used, the decomposition rate tends to slow down, the decomposition time to be prolonged, and the efficiency tends to deteriorate. Therefore, the molar ratio of alkali metal hydroxide to 1 mole of repeating unit of polycarbonate resin ((mass of alkali metal hydroxide used [g] / molecular weight of alkali metal hydroxide [g / mol]) / (mass of polycarbonate resin used [g] / molecular weight of repeating unit [g / mol])) is preferably 0.0001 or more, more preferably 0.0005 or more, and even more preferably 0.0007 or more. For example, it can be set to 0.001 or more, 0.01 or more, 0.1 or more, etc. If the amount of alkali metal hydroxide used is large relative to the amount of polycarbonate resin used, the amount of acid required for neutralization after decomposition tends to increase, and the manufacturing efficiency tends to decrease. Therefore, the molar ratio of alkali metal hydroxide to 1 mole of repeating unit of polycarbonate resin is preferably 1 or less, more preferably 0.9 or less, and even more preferably 0.8 or less.

[0113] [Alkali metal carbonates]

[0114] Alkali metal carbonates are alkali metal ions (M + ) and carbonate ions (CO3) 2- The salt of ) is a compound represented by M2CO3 (M represents an alkali metal atom). Sodium carbonate or potassium carbonate are preferred as alkali metal carbonates.

[0115] If the amount of alkali metal carbonate used is small relative to the amount of polycarbonate resin used, the decomposition rate tends to slow down, the decomposition time to be prolonged, and the efficiency tends to deteriorate. Therefore, the molar ratio of alkali metal carbonate to 1 mole of repeating unit of polycarbonate resin ((mass of alkali metal carbonate used [g] / molecular weight of alkali metal carbonate [g / mol]) / (mass of polycarbonate resin used [g] / molecular weight of repeating unit [g / mol])) is preferably 0.0001 moles or more, more preferably 0.0005 moles or more, and even more preferably 0.001 moles or more. For example, it can be set to 0.001 moles or more, 0.01 moles or more, 0.1 moles or more, etc. If the amount of alkali metal carbonate used is large relative to the amount of polycarbonate resin used, the amount of acid required for neutralization after decomposition tends to increase, and the manufacturing efficiency tends to decrease. Therefore, the molar ratio of alkali metal carbonate to 1 mole of repeating unit of polycarbonate resin is preferably 1 or less, more preferably 0.9 or less, and even more preferably 0.8 or less.

[0116] [alkylamine]

[0117] Alkylamines are compounds in which at least one hydrogen atom of ammonia is replaced by an alkyl group. Monoalkylamines, which are primary amines, react with the carbonate bond portion of polycarbonate resins to form isocyanates; therefore, dialkylamines, which are secondary amines, and trialkylamines, which are tertiary amines, are more preferred.

[0118] Dialkylamines, as secondary amines, react with the carbonate bond portion of polycarbonate resin to generate tetraalkylurea; therefore, trialkylamines, as tertiary amines, are even more preferred.

[0119] Alkylamines preferably have a boiling point of 200°C or lower, more preferably 160°C or lower. At such boiling points, they can be removed by reducing pressure and / or heating along with aromatic monohydric alcohols such as phenol. Furthermore, if the boiling point is too low, the alkylamine may volatilize during the decomposition reaction, reducing the decomposition rate; therefore, the boiling point of the alkylamine is preferably 10°C or higher, more preferably 30°C or higher.

[0120] Alkylamines are preferably represented by general formula (I).

[0121]

[0122] In general formula (I), R A R represents an alkyl group having 1 to 3 carbon atoms. B ~R C Each can be independently represented by a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.

[0123] R A Preferred compounds are methyl, ethyl, n-propyl, or isopropyl, R. B ~R CEach of the following is independently preferred: hydrogen atom, methyl, ethyl, n-propyl, or isopropyl.

[0124] Specific examples of alkylamines represented by general formula (I) include methylamine, ethylamine, propylamine, dimethylamine, diethylamine, trimethylamine, triethylamine, etc.

[0125] If the amount of alkylamine used is small relative to the amount of polycarbonate resin used, the decomposition rate tends to slow down, the decomposition time is prolonged, and the efficiency deteriorates. Therefore, the molar ratio of alkylamine to 1 mole of repeating unit of polycarbonate resin ((mass of alkylamine used [g] / molecular weight of alkylamine [g / mol]) / (mass of polycarbonate resin used [g] / molecular weight of repeating unit [g / mol])) is preferably 0.0005 or more, more preferably 0.0007 or more, and even more preferably 0.001 or more. For example, it can be set to 0.01 or more, 0.1 or more, etc. If the amount of alkylamine used is large relative to the amount of polycarbonate resin used, it is easier to generate amine odor, or it is less likely to form dialkyl carbonate and / or alkyl aryl carbonate. Therefore, the molar ratio of alkylamine to 1 mole of repeating unit of polycarbonate resin is preferably smaller than 4.5, and the smaller the ratio is in the order of 4.0 or less, 3.0 or less, 2.0 or less, 1.0 or less, 0.9 or less, and 0.8 or less, the better.

[0126] [acid]

[0127] Examples of acids include inorganic acids such as hydrochloric acid, sulfuric acid, and phosphoric acid, and organic acids such as carboxylic acids and sulfonic acids. Preferably, any acid selected from the group consisting of sulfuric acid, phosphoric acid, and sulfonic acids is preferred. Sulfonic acids include alkyl sulfonic acids such as methanesulfonic acid and aromatic sulfonic acids such as toluenesulfonic acid.

[0128] If the amount of acid used is small relative to the amount of polycarbonate resin used, the decomposition rate tends to slow down, the decomposition time to be prolonged, and the efficiency tends to deteriorate. Therefore, the molar ratio of acid to 1 mole of repeating unit of polycarbonate resin ((mass of acid used [g] / molecular weight of acid [g / mol]) / (mass of polycarbonate resin used [g] / molecular weight of repeating unit [g / mol])) is preferably 0.0001 moles or more, more preferably 0.0005 moles or more, and even more preferably 0.0007 moles or more. If the amount of acid used is large relative to the amount of polycarbonate resin used, the amount of alkali required for neutralization after decomposition tends to increase, and the manufacturing efficiency tends to decrease. Therefore, the molar ratio of acid to 1 mole of repeating unit of polycarbonate resin is preferably 1 or less, more preferably 0.9 or less, and even more preferably 0.8 or less.

[0129] (Reaction solution)

[0130] The prepared reaction solution is a slurry-like solution in which polycarbonate resin is dispersed in a liquid component comprising aromatic monohydric alcohols and aliphatic monohydric alcohols. The slurry concentration (mass of solid components in the reaction solution / mass of the reaction solution) is preferably 0.01 or more, more preferably 0.05 or more. Furthermore, it is preferably 0.5 or less, more preferably 0.3 or less. If the slurry concentration (concentration of solid components) is too low, the decomposition efficiency decreases; if the slurry concentration is too high, mixing becomes poor.

[0131] The liquid components in the prepared reaction solution are mainly aromatic monohydric alcohols and aliphatic monohydric alcohols. The total mass of aromatic monohydric alcohols and aliphatic monohydric alcohols relative to the total mass of all liquid components is 0.8 or more, 0.9 or more, 0.95 or more, etc.

[0132] The total mass of polycarbonate resin, aromatic monohydric alcohol, aliphatic monohydric alcohol, and catalyst relative to the mass of the reaction solution can be set to 0.9 or more, 0.95 or more, 0.98 or more, 0.99 or more, etc. Alternatively, the reaction solution may also contain polycarbonate resin, aromatic monohydric alcohol, aliphatic monohydric alcohol, and catalyst.

[0133] When simultaneously obtaining bisphenol and dialkyl carbonate and / or alkyl aryl carbonate, the resulting dialkyl carbonate and / or alkyl aryl carbonate becomes easily decomposed if water is present in the reaction solution. Therefore, the water content in the reaction solution (mass of water / mass of reaction solution) is typically 0.005 or less. Preferably, the water content in the reaction solution is 0.001 or less, more preferably 0.0005 or less.

[0134] (Preparation of the reaction solution)

[0135] The preparation of the reaction solution is preferably carried out at a temperature above 10°C, more preferably at a temperature above 20°C. Furthermore, the preparation of the reaction solution is preferably carried out at a temperature below 40°C, more preferably at a temperature below 35°C. If the temperature during reaction solution preparation is too low, it tends to solidify depending on the type of aromatic monohydric alcohol, leading to poor mixing and sometimes difficulty in achieving uniform mixing. Conversely, if the temperature during reaction solution preparation is too high, it tends to volatilize depending on the type of catalyst, raising concerns about difficulty in achieving the desired concentration and controlling the decomposition reaction.

[0136] The mixing order of polycarbonate resin, aromatic monohydric alcohol, aliphatic monohydric alcohol, and catalyst is not particularly limited. For example, the aromatic monohydric alcohol, aliphatic monohydric alcohol, and catalyst can be supplied to the polycarbonate resin in sequence, or the aromatic monohydric alcohol can be supplied to the polycarbonate resin, aliphatic monohydric alcohol, and catalyst in sequence. To achieve more uniform mixing, the polycarbonate resin is preferably supplied to the reaction vessel after the aromatic monohydric alcohol and / or aliphatic monohydric alcohol.

[0137] (Decomposition reaction)

[0138] Due to the presence of aromatic monohydric alcohols, aliphatic monohydric alcohols, and catalysts, the carbonate bonds in polycarbonate resin are cleaved, causing decomposition. This results in the formation of polycarbonate resin decomposition products (decomposition products) containing bisphenols and carbonyl compounds. The generated carbonyl compounds include dialkyl carbonates and / or alkyl aryl carbonates. Depending on the amount of aromatic and aliphatic monohydric alcohols in the slurry-like reaction solution, the generated carbonyl compounds are predominantly dialkyl carbonates, or a mixture of dialkyl carbonates and alkyl aryl carbonates.

[0139] For example, as described above, by setting the molar ratio of the aliphatic monohydric alcohol to the repeating unit 1 mole of the polycarbonate resin to 2.0 or more, the reaction shown in the following reaction formula (2) preferably occurs. This allows for the efficient decomposition of the polycarbonate resin into bisphenol and dialkyl carbonate. It should be noted that in reaction formula (2), R... 1 ~R 6 , n has the same meaning as the above general formula (1), R 7 It is an alkyl group.

[0140]

[0141] In addition, by setting the molar ratio of aliphatic monohydric alcohol to polycarbonate resin repeating unit 1 mole in the reaction solution to less than 2.0, decomposition products containing bisphenol and dialkyl carbonate and / or alkyl aryl carbonate can be obtained.

[0142] It should be noted that the decomposition process can include: a preparation step, which prepares a slurry-like reaction solution containing polycarbonate resin, aromatic monohydric alcohol, aliphatic monohydric alcohol, and a catalyst; and a decomposition reaction step, which decomposes the polycarbonate resin in the aforementioned reaction solution. In this case, to control the concentration of the polycarbonate resin and the temperature during the preparation of the reaction solution (in the mixture of polycarbonate resin, aromatic monohydric alcohol, aliphatic monohydric alcohol, and catalyst) without a decomposition reaction, the process can be clearly divided into a preparation step and a decomposition reaction step. However, it can also be less clearly divided into an adjustment step and a decomposition step. In the reaction solution preparation step, a portion of the polycarbonate resin can dissolve and undergo a decomposition reaction, thereby decomposing a portion of the polycarbonate resin. By partially decomposing the polycarbonate resin in the reaction solution preparation step, the decomposition reaction can be carried out more efficiently.

[0143] The decomposition reaction can be carried out under normal pressure or under pressure, but even under normal pressure, the reaction will proceed fully, so it is preferred to carry it out under normal pressure.

[0144] (Reaction temperature)

[0145] The preparation of the reaction solution and the cessation of the decomposition reaction can be carried out at the same temperature as when the reaction solution was prepared, but it is preferable to raise the temperature to the predetermined reaction temperature after the reaction solution is prepared (after mixing the polycarbonate resin, aromatic monohydric alcohol, aliphatic monohydric alcohol, and catalyst). If the temperature during reaction solution preparation is too high, there is a concern that controlling the decomposition reaction will become difficult. Raising the temperature after the reaction solution is prepared allows the decomposition reaction to proceed stably, and is therefore preferred.

[0146] The reaction temperature should be appropriately selected based on the type of aromatic monohydric alcohol and the reaction time. However, at high temperatures, the aliphatic monohydric alcohols in the reaction solution will evaporate, stopping the alcoholysis. Furthermore, at low temperatures, the aromatic monohydric alcohols will solidify or become difficult to decompose with solvents, reducing the reaction rate and thus prolonging the decomposition time. Based on these factors, a reaction temperature of 60°C or higher is preferred, with higher values ​​in the order of 70°C or higher, 75°C or higher, and 80°C or higher being more preferred. Additionally, a temperature below 120°C is preferred, with lower values ​​in the order of 110°C or lower, 100°C or lower, and 95°C being more preferred.

[0147] In particular, the decomposition of polycarbonate resin is preferably carried out at a reaction temperature of 60-120°C and at atmospheric pressure, more preferably at a reaction temperature of 70-110°C and at atmospheric pressure, and even more preferably at a reaction temperature of 80-100°C and at atmospheric pressure.

[0148] It should be noted that when the reaction is carried out at the same temperature as during the preparation of the reaction solution, the reaction temperature is the average temperature from the moment the mixing of the polycarbonate resin, aromatic monohydric alcohol, aliphatic monohydric alcohol, and catalyst ends to the moment the neutralization and distillation removal operations for stopping the decomposition reaction begin. Alternatively, when the reaction is carried out by raising the temperature after the reaction solution is prepared, the average temperature is the average temperature from the moment the predetermined temperature is reached to the moment the neutralization and distillation removal operations for stopping the decomposition reaction begin.

[0149] (Reaction time)

[0150] The reaction time should be appropriately selected based on the slurry concentration, reaction temperature, etc. If the reaction time is too long, the generated bisphenols tend to decompose; therefore, a reaction time of 30 hours or less is preferred, with shorter times in the order of 25 hours or less, 20 hours or less, 15 hours or less, 10 hours or less, and 5 hours or less being more preferred. Furthermore, if the reaction time is too short, the decomposition reaction may not proceed completely; therefore, a reaction time of 0.1 hours or more is preferred, more preferably 0.5 hours or more, and even more preferably 1 hour or more is preferred.

[0151] It should be noted that the reaction time is the time from the end of mixing of the polycarbonate resin, aromatic monohydric alcohol, aliphatic monohydric alcohol, and catalyst to the start of the neutralization and distillation operations used to stop the decomposition reaction. The endpoint of the reaction time can be determined by tracking the decomposition reaction using methods such as liquid chromatography.

[0152] (Methods to stop the decomposition reaction of polycarbonate resin)

[0153] The method for stopping the decomposition reaction of polycarbonate resin is appropriately selected depending on the type of catalyst used. When using an alkylamine as a catalyst, the decomposition reaction can be stopped by distillation or neutralization of the alkylamine. In methods that remove alkylamines by neutralization with an acid, ammonium salts are generated, and their removal is also necessary; therefore, distillation is the preferred method for removing alkylamines. Alternatively, when using alkali metal hydroxides, alkali metal carbonates, or acids as catalysts, the decomposition reaction can be stopped by neutralization or similar methods.

[0154] <Methods for manufacturing bisphenol>

[0155] This invention relates to a method for manufacturing bisphenol (hereinafter sometimes referred to as "the method for manufacturing bisphenol of the present invention"), comprising: a decomposition step, wherein a polycarbonate resin is decomposed using the decomposition method of the present invention; and a bisphenol recovery step, wherein the bisphenol generated by the decomposition of the aforementioned polycarbonate resin is recovered. Specifically, the method for manufacturing bisphenol of the present invention comprises: a decomposition step, wherein the aforementioned polycarbonate resin is decomposed in a slurry-like reaction solution comprising a polycarbonate resin, an aromatic monohydric alcohol, an aliphatic monohydric alcohol, and a catalyst; and a bisphenol recovery step, wherein the bisphenol generated in the aforementioned decomposition step is recovered. Alternatively, the method for manufacturing bisphenol of the present invention may comprise: a preparation step, wherein a slurry-like reaction solution comprising a polycarbonate resin, an aromatic monohydric alcohol, an aliphatic monohydric alcohol, and a catalyst is prepared; a decomposition reaction step, wherein the aforementioned polycarbonate resin is decomposed in the slurry-like reaction solution prepared in the aforementioned preparation step; and a bisphenol recovery step, wherein the bisphenol generated in the aforementioned decomposition reaction step is recovered.

[0156] As described above, in the decomposition method of the present invention, bisphenol is generated as a decomposition product; therefore, the decomposition method of the present invention can be used in the manufacturing method of bisphenol. The decomposition steps are as described in the decomposition method of the present invention.

[0157] The method for manufacturing bisphenol of the present invention is suitable as a method for manufacturing 2,2-bis(4-hydroxyphenyl)propane (hereinafter sometimes referred to as "bisphenol A").

[0158] Bisphenol Recovery Process

[0159] The bisphenol manufacturing method of the present invention includes a bisphenol recovery step for the bisphenol obtained in the decomposition process. The recovery of bisphenol from the reaction solution after the self-decomposition reaction can be carried out by means of crystallization, column chromatography, etc., after the decomposition reaction of polycarbonate resin has been stopped.

[0160] The bisphenol recovery step in the bisphenol manufacturing method of the present invention preferably includes a crystallization step for recovering bisphenol by crystallization. Specifically, after the decomposition reaction of polycarbonate resin, the catalyst, solvent, and carbonyl compound in the reaction solution are removed, and an organic solvent is added and mixed. The resulting organic phase is washed with water or brine, and then neutralized and washed with ammonium chloride solution as needed. Next, the washed organic phase is cooled to allow crystallization.

[0161] As organic solvents that can be used during neutralization and crystallization, aromatic hydrocarbons such as toluene, xylene, ethylbenzene, diethylbenzene, isopropylbenzene, and mesitylene, aliphatic hydrocarbons such as hexane, heptane, octane, nonane, decane, undecane, and dodecane, methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, tert-butanol, n-pentanol, isopentanol, n-hexanol, n-heptanol, n-octanol, n-nonanol, n-decanol, n-undecylol, n-dodecylol, ethylene glycol, diethylene glycol, and triethylene glycol can be used.

[0162] It should be noted that the remaining aromatic monohydric alcohol and organic solvent can be removed by distillation before crystallization. Additionally, if bisphenol A crystallizes in the presence of phenol, it will form a eutectic with phenol. Phenol is used to crystallize the R-unit containing repeating units derived from bisphenol A (R in the above general formula (1)). 1 ~R 4 For hydrogen atoms, R 5 R 6 In the case of polycarbonate resin decomposition (where methyl repeating units are present), phenol must be removed by distillation before crystallization in order to prevent the formation of eutectic.

[0163] Furthermore, as described above, in the decomposition method of the present invention, dialkyl carbonates and / or alkylaryl carbonates are produced as decomposition products in addition to bisphenol. The method for producing bisphenol of the present invention using the decomposition method of the present invention may also include a step for recovering these decomposition products.

[0164] That is, the method for manufacturing bisphenol of the present invention can include a dialkyl carbonate recovery step for recovering dialkyl carbonate obtained in the decomposition step. The recovery of dialkyl carbonate can be carried out in the same manner as the recovery of dialkyl carbonate in the method for manufacturing dialkyl carbonate described later.

[0165] Furthermore, the method for manufacturing bisphenol of the present invention may include a alkyl aryl carbonate recovery step for recovering the alkyl aryl carbonate obtained in the decomposition step. The recovery of the alkyl aryl carbonate can be carried out in the same manner as the recovery of the alkyl aryl carbonate in the method for manufacturing the alkyl aryl carbonate described later.

[0166] The following is based on Figures 2-4 Taking the bisphenol manufacturing methods (A) to (C) as examples, the bisphenol manufacturing methods of the present invention will be described in more detail. In the bisphenol manufacturing methods (A) to (C), as representative examples, phenol is used as an aromatic monohydric alcohol, methanol is used as an aliphatic monohydric alcohol, and a polycarbonate resin (bisphenol A type polycarbonate resin) containing repeating units derived from bisphenol A is used as the polycarbonate resin.

[0167] <Method for manufacturing bisphenol (A)>

[0168] Figure 2 The method (A) for manufacturing bisphenol shown comprises: step (A1), decomposing the polycarbonate resin in a slurry-like reaction solution containing a polycarbonate resin of type bisphenol A, phenol, methanol, and an alkali metal hydroxide as a catalyst; step (A2), neutralizing the reaction solution after step (A1) to obtain an organic phase containing dissolved bisphenol A; and step (A3), recovering bisphenol A by crystallization after subjecting the organic phase obtained in step (A2) to reduced pressure and / or heating.

[0169] In the bisphenol manufacturing method (A) of the present invention, step (A1) is a decomposition step, and steps (A2) and (A3) are bisphenol recovery steps.

[0170] In step (A2), the reaction solution, acid, and water are mixed and neutralized, allowing for oil-water separation. The separated aqueous phase is then removed. Alkali metal hydroxides, the acid added for neutralization, and the salt produced through neutralization are contained in the aqueous phase; therefore, removing the aqueous phase also removes the alkali metal hydroxides. This yields an organic phase in which bisphenol A is dissolved.

[0171] Examples of acids used in neutralization include hydrochloric acid, sulfuric acid, and phosphoric acid. Neutralization based on acid mixing can be carried out with the reaction solution at a pH less than 7 or at a pH greater than 7. However, if the pH is less than 7, there is a concern that the quality of the separated bisphenol A may be reduced. Therefore, acid mixing is preferably carried out with the reaction solution at a pH greater than 7 (e.g., pH 7.5 or higher, pH 8.0 or higher). On the other hand, if the pH of the reaction solution is too high, dimethyl carbonate and / or methylphenol carbonate are easily hydrolyzed, resulting in a lower yield when recovering dimethyl carbonate and / or methylphenol carbonate. Therefore, acid mixing is carried out with a pH of 10 or lower, preferably 9.5 or lower.

[0172] Alternatively, an organic solvent such as an aromatic hydrocarbon can be mixed before or after mixing the acid. After neutralization by mixing the acid, water, and organic solvent in the reaction solution, the oil and water are separated, and the aqueous phase is removed, thereby obtaining an organic phase containing dissolved bisphenol A. By mixing the organic solvent, oil-water separation becomes easier, thus making the removal of the aqueous phase containing dissolved alkali metal hydroxides easier.

[0173] In step (A3), the organic phase obtained in step (A2) is subjected to reduced pressure and / or heating, and then bisphenol A is recovered by crystallization. In the presence of phenol during crystallization, bisphenol A forms a eutectic with phenol and precipitates. Therefore, to obtain bisphenol A, phenol is removed before crystallization in step (A3). Specifically, the organic phase obtained in step (A2) is subjected to reduced pressure and / or heating to remove liquid components such as phenol, methanol, and dimethyl carbonate by distillation, yielding crude bisphenol A. Next, an organic solvent such as an aromatic hydrocarbon is added to the crude bisphenol A to prepare a crystallization solution containing dissolved bisphenol A. This solution is then cooled to precipitate bisphenol A. The precipitated bisphenol A is recovered through solid-liquid separation.

[0174] It should be noted that if methanol is used in a molar ratio of 2.0 or more of methanol to 1 repeating unit of polycarbonate resin, it is preferable that the reaction of decomposing the bisphenol A type polycarbonate resin into 2,2-bis(4-hydroxyphenyl)propane (bisphenol A) and dimethyl carbonate occurs. In this case, if... Figure 5 As shown, in step (A3), firstly, the azeotropic mixture of dimethyl carbonate and methanol is distilled away from the organic phase obtained in step (A2). Next, phenol is distilled away. For example, at atmospheric pressure (101 kPa), the organic phase obtained in step (A2) is transferred to a distillation apparatus, heated to 65–250°C (preferably 90–200°C), and / or reduced to 0.1–100 kPa (preferably 10–100 kPa), thereby distilling away the azeotropic mixture of methanol and dimethyl carbonate, followed by distilling away phenol. An organic solvent is added to the crude bisphenol A product obtained from the distillation to induce crystallization, thereby obtaining bisphenol A.

[0175] If methanol is used in a molar ratio of less than 2.0 to 1 repeating unit of polycarbonate resin, a large amount of methylphenyl carbonate will be generated as a decomposition product. In this case, if... Figure 6As shown, in step (A3), firstly, the azeotropic mixture of dimethyl carbonate and methanol is distilled off from the organic phase obtained in step (A2). Next, phenol is distilled off, followed by the distillation of methyl phenyl carbonate. For example, the organic phase obtained in step (A2) is transferred to a distillation apparatus at atmospheric pressure (101 kPa), and the temperature is raised to 65–200 °C, and / or the pressure is reduced to 0.1–50 kPa, thereby first distilling off the azeotropic mixture of methanol and dimethyl carbonate, then distilling off phenol, and finally distilling off methyl phenyl carbonate. An organic solvent is added to the resulting crude bisphenol A product for crystallization, thereby obtaining bisphenol A.

[0176] Alternatively, when using alkali metal carbonates as catalysts, the process can be carried out using the same method as the bisphenol manufacturing method (A).

[0177] <Method for manufacturing bisphenol (B)>

[0178] Figure 3 The method (B) for manufacturing bisphenol shown includes: step (B1), in which the polycarbonate resin is decomposed in a slurry-like reaction solution containing a polycarbonate resin of type bisphenol A, phenol, methanol, and an alkylamine as a catalyst; and step (B2), in which the reaction solution after step (B1) is subjected to reduced pressure and / or heated, and then bisphenol A is recovered by crystallization.

[0179] In the bisphenol manufacturing method (B) of the present invention, step (B1) is a decomposition step and step (B2) is a bisphenol recovery step.

[0180] For step (B2), specifically, the reaction solution after step (B1) is subjected to reduced pressure and / or heating to remove liquid components such as alkylamine, phenol, methanol, and dimethyl carbonate by distillation, yielding crude bisphenol A. Next, an organic solvent such as an aromatic hydrocarbon is added to the crude bisphenol A to prepare a crystallization solution containing dissolved bisphenol A. This solution is then cooled to precipitate bisphenol A. The precipitated bisphenol A is recovered through solid-liquid separation.

[0181] It should be noted that, depending on the amount of methanol relative to the polycarbonate resin, in step (B2), the pressure and temperature for distilling off the liquid components are controlled in the same way as in step (A3) of the bisphenol manufacturing method (A).

[0182] When methanol is used in a molar ratio of 2.0 or higher relative to 1 mole of polycarbonate resin repeating unit, the azeotropic mixture of dimethyl carbonate and methanol, alkylamine, and phenol are distilled off from the reaction solution after step (B1) to obtain crude bisphenol A. The azeotropic mixture of dimethyl carbonate and methanol, alkylamine, and phenol are removed by distillation in order of decreasing boiling point. For example, if the boiling point of the azeotropic mixture of dimethyl carbonate and methanol is less than the boiling point of the alkylamine, which is less than the boiling point of phenol, then... Figure 7 As shown, first, the azeotropic mixture of dimethyl carbonate and methanol is removed by distillation, then the alkylamine is removed by distillation, and finally the phenol is removed by distillation.

[0183] When methanol is used in a manner where the molar ratio of methanol to polycarbonate resin repeating unit 1 is less than 2.0, the azeotropic mixture of dimethyl carbonate and methanol, alkylamine, phenol, and methylphenyl carbonate are distilled off from the reaction solution after step (B1) to obtain crude bisphenol A. The azeotropic mixture of dimethyl carbonate and methanol, alkylamine, phenol, and methylphenyl carbonate are distilled off in order of decreasing boiling point. For example, if the boiling point of the azeotropic mixture of dimethyl carbonate and methanol is less than the boiling point of the alkylamine, which is less than the boiling point of the phenol, which is less than the boiling point of methylphenyl carbonate, then... Figure 8 As shown, first, the azeotropic mixture of dimethyl carbonate and methanol is removed by distillation, then the alkylamine is removed by distillation, then the phenol is removed by distillation, and finally the methyl phenyl carbonate is removed by distillation.

[0184] When using alkylamines as catalysts, the alkylamines can be removed by neutralization with supplied acid. In this case, as in step (A2) of the bisphenol manufacturing method (A), acid and water are mixed in the reaction solution after the decomposition reaction for neutralization, followed by oil-water separation. The aqueous phase is removed, thereby obtaining an organic phase containing dissolved bisphenol A. Next, as in step (A3) of the bisphenol manufacturing method (A), the obtained organic phase is subjected to reduced pressure and / or heating, and bisphenol A can be recovered by crystallization.

[0185] Thus, methods for removing alkylamines from the decomposition reaction solution of polycarbonate resin include distillation and neutralization with acid. In the acid neutralization method, ammonium salts are generated, and their removal is also necessary; therefore, distillation is preferred. By using alkylamines as catalysts, alkylamines can be removed together with phenol by reduced pressure and / or heating, eliminating the need for neutralization and simplifying purification.

[0186] <Method for manufacturing bisphenol (C)>

[0187] Figure 4The method (C) for manufacturing bisphenol shown comprises: step (C1), decomposing the polycarbonate resin in a slurry-like reaction solution containing a polycarbonate resin of type bisphenol A, phenol, methanol, and an acid as a catalyst; step (C2), neutralizing the reaction solution after step (C1) to obtain an organic phase containing dissolved bisphenol A; and step (C3), recovering bisphenol A by crystallization after subjecting the organic phase obtained in step (C2) to reduced pressure and / or heating.

[0188] In the bisphenol manufacturing method (C) of the present invention, step (C1) is a decomposition step, and steps (C2) and (C3) are bisphenol recovery steps.

[0189] In step (C2), the reaction solution, alkali, and water are mixed and neutralized, and then the oil and water are separated. The separated aqueous phase is removed to obtain an organic phase containing dissolved bisphenol A. Alternatively, the mixture of reaction solution, alkali, water, and organic solvent is separated into oil and water, and the aqueous phase is removed to obtain an organic phase containing dissolved bisphenol A.

[0190] Examples of bases used in neutralization include sodium carbonate and sodium hydroxide. Similarly to step (A2) of the bisphenol manufacturing method (A), neutralization is preferably carried out when the pH of the reaction solution is greater than 7, which is the endpoint. For example, it is preferable to mix the base to achieve a pH of 7.5 or higher, or a pH of 8.0 or higher. Furthermore, it is preferable to mix the base to achieve a pH of 10 or lower, or a pH of 9.5 or lower.

[0191] In step (C3), bisphenol A is recovered from the organic phase containing dissolved bisphenol A obtained in step (C2). Similar to step (A3) of the bisphenol manufacturing method (A), bisphenol A can be recovered by crystallization after the organic phase obtained in step (C2) is subjected to reduced pressure and / or heating.

[0192] Furthermore, similarly to the organic phase obtained in step (A2), the organic phase obtained in step (C2) contains bisphenol A, methanol, phenol, and dimethyl carbonate and / or methyl phenyl carbonate, depending on the amount of methanol used in step (C1). The method for removing methanol, phenol, and dimethyl carbonate and / or methyl phenyl carbonate from this organic phase by distillation can be carried out in the same manner as in step (A3).

[0193] It should be noted that the methods for manufacturing bisphenol (A) to (C) are examples using phenol as an aromatic monohydric alcohol. When using aromatic monohydric alcohols other than phenol, such as cresol or xylenol, bisphenol A does not form a eutectic. Therefore, the removal of aromatic monohydric alcohols based on reduced pressure and / or heating in steps (A3), (B2), and (C3) is not necessary. In this case, cooling the reaction solution after step (B1), the organic phase obtained in step (A2), and (C2) allows bisphenol A to precipitate, enabling its recovery. Using cresol or xylenol simplifies the purification of bisphenol A.

[0194] Alternatively, bisphenol A can be recovered as a eutectic of bisphenol A and phenol. In this case, instead of removing the phenol by distillation, the reaction solution after step (B1), the organic phase obtained in step (A2), and the organic phase obtained in step (C2) are cooled to allow the eutectic of bisphenol A and phenol to precipitate and be recovered.

[0195] Furthermore, as described above, the polycarbonate resin used in the bisphenol manufacturing method of the present invention is not limited to bisphenol A type polycarbonate resin. The bisphenol manufacturing method of the present invention, using a polycarbonate resin containing repeating units of bisphenol other than bisphenol A, can also be appropriately implemented in the same manner as the bisphenol manufacturing methods (A) to (C) described above.

[0196] <Uses of Bisphenol>

[0197] The bisphenol obtained by the method of manufacturing bisphenol of the present invention (hereinafter, sometimes referred to as "recycled bisphenol") can be used as a component, curing agent, additive, or precursor of various thermoplastic resins such as polyether resins, polyester resins, polyarylate resins, polycarbonate resins, polyurethane resins, and acrylic resins, as well as epoxy resins, unsaturated polyester resins, phenolic resins, polybenzoxazine resins, and cyanate ester resins, for various applications such as optical materials, recording materials, insulating materials, transparent materials, electronic materials, adhesive materials, and heat-resistant materials. Furthermore, it is also useful as a color developer, anti-fading agent, bactericide, and antibacterial / antifungal agent for heat-sensitive recording materials.

[0198] Of these, in order to impart good mechanical properties, they are preferably used as raw materials (monomers) for thermoplastic resins and thermosetting resins, and more preferably as raw materials for polycarbonate resins and epoxy resins. In addition, they are also preferably used as color developers, and more preferably in combination with leuco dyes and color-changing temperature regulators.

[0199] <Method for manufacturing dialkyl carbonates>

[0200] This invention relates to a method for manufacturing dialkyl carbonates (hereinafter sometimes referred to as "the method for manufacturing dialkyl carbonates of the present invention"), comprising: a decomposition step, wherein a polycarbonate resin is decomposed using the decomposition method of the present invention; and a dialkyl carbonate recovery step, wherein the dialkyl carbonates generated by the decomposition of the aforementioned polycarbonate resin are recovered. Specifically, the method for manufacturing dialkyl carbonates of the present invention comprises: a decomposition step, wherein the aforementioned polycarbonate resin is decomposed in a slurry-like reaction solution comprising a polycarbonate resin, an aromatic monohydric alcohol, an aliphatic monohydric alcohol, and a catalyst; and a dialkyl carbonate recovery step, wherein the dialkyl carbonates generated in the aforementioned decomposition step are recovered. Alternatively, the method for manufacturing dialkyl carbonates of the present invention may comprise: a preparation step, wherein a slurry-like reaction solution comprising a polycarbonate resin, an aromatic monohydric alcohol, an aliphatic monohydric alcohol, and a catalyst is prepared; a decomposition reaction step, wherein the aforementioned polycarbonate resin is decomposed in the slurry-like reaction solution prepared in the aforementioned preparation step; and a dialkyl carbonate recovery step, wherein the dialkyl carbonates generated in the aforementioned decomposition reaction step are recovered.

[0201] As described above, in the decomposition method of the present invention, dialkyl carbonate can be generated as a decomposition product; therefore, the decomposition method of the present invention can be used in the manufacturing method of dialkyl carbonate. The decomposition steps are as described in the decomposition method of the present invention.

[0202] The method for manufacturing dialkyl carbonate of the present invention is suitable as a method for manufacturing dimethyl carbonate, diethyl carbonate or dibutyl carbonate.

[0203] To manufacture dialkyl carbonate more efficiently, the molar ratio of the aforementioned aliphatic monohydric alcohol to 1 mole of the aforementioned polycarbonate resin repeating unit is preferably 2.0 or more, more preferably 2.1 or more, and even more preferably 2.2 or more. Furthermore, from the viewpoint of manufacturing efficiency, the upper limit is preferably 6.0 or less, more preferably 5.5 or less, and even more preferably 5.0 or less.

[0204] <Dialkyl carbonate recovery process>

[0205] The recovery (separation, purification) of dialkyl carbonates can be carried out using conventional methods. For example, a method can be employed where the reaction solution is neutralized. The neutralized organic phase is then heated and / or subjected to reduced pressure followed by distillation. Distillation can be performed, for example, under reduced pressure of 50–100 kPa and / or heated to 65–120 °C.

[0206] It should be noted that, since dimethyl carbonate and methanol are azeotropic, the preferred method for recovering dimethyl carbonate is, for example, the following method: distilling the reaction solution or the organic phase after neutralizing the reaction solution to obtain a mixture of dimethyl carbonate and methanol, then adding water to the mixture of dimethyl carbonate and methanol to extract the methanol into the aqueous phase and remove it.

[0207] Figure 9 , 10 A flowchart illustrating an example of a method for manufacturing dialkyl carbonates according to the present invention. Figure 9 , 10 In the manufacturing methods (D) and (E) of the dialkyl carbonate shown, phenol is used as an aromatic monohydric alcohol, methanol is used as an aliphatic monohydric alcohol, and a bisphenol A type polycarbonate resin is used as the polycarbonate resin, as representative examples.

[0208] Figure 9 The method (D) for manufacturing dialkyl carbonate shown comprises: step (D1), decomposing the polycarbonate resin in a slurry-like reaction solution containing a bisphenol A type polycarbonate resin, phenol, methanol, and an alkali metal hydroxide as a catalyst; step (D2), neutralizing the reaction solution after step (D1) to obtain an organic phase containing bisphenol A, dimethyl carbonate, methanol, and phenol; step (D3), distilling the organic phase obtained in step (D2) to obtain an azeotropic mixture of dimethyl carbonate and methanol; and step (D4), adding water to the aforementioned azeotropic mixture to extract methanol into the aqueous phase and recovering dimethyl carbonate.

[0209] Figure 9 The method (D) shown is for the manufacture of dialkyl carbonates by means of... Figure 5 and Figure 6 The dimethyl carbonate distillate distilled from step (A3) of the bisphenol manufacturing method (A) shown is used in step (D4) to produce an azeotropic mixture of methanol. Figure 9 The azeotropic mixture of dimethyl carbonate and methanol obtained in process (D3) and Figure 5 and Figure 6 The dimethyl carbonate distilled from step (A3) of the bisphenol manufacturing method (A) is the same as the azeotropic mixture of methanol. Furthermore, phenol and other substances are further removed by distillation from the unevaporated bottoms liquid remaining in step (D3), followed by crystallization, thereby obtaining bisphenol A. Figure 9 The processes (D1) to (D2) can be completed by communicating with... Figure 2 The same method is used to carry out the steps (A1) to (A2) of the bisphenol manufacturing method (A).

[0210] Furthermore, in the method for producing dialkyl carbonate (D), an acid can be used as a catalyst, and a base is used for neutralization. In this case, the azeotropic mixture of dimethyl carbonate and methanol obtained in step (D3) is the same as the azeotropic mixture of dimethyl carbonate and methanol distilled in step (C3) of the method for producing bisphenol (C).

[0211] Figure 10The method (E) for manufacturing dialkyl carbonate shown comprises: step (E1), decomposing the polycarbonate resin in a slurry-like reaction solution containing a bisphenol A type polycarbonate resin, phenol, methanol, and an alkylamine as a catalyst; step (E2), distilling the reaction solution after step (E1) to obtain an azeotropic mixture of dimethyl carbonate and methanol; and step (E3), adding water to the aforementioned azeotropic mixture to extract methanol into the aqueous phase and recover dimethyl carbonate.

[0212] Figure 10 The method (E) for producing dialkyl carbonate shown is for... Figure 7 and Figure 8 The dimethyl carbonate distillate distilled from step (B2) of the bisphenol manufacturing method (B) shown is used in step (E3) as an azeotropic mixture with methanol. Figure 10 The azeotropic mixture of dimethyl carbonate and methanol obtained in process (E2) and Figure 7 and Figure 8 The dimethyl carbonate distilled from step (B2) of the bisphenol manufacturing method (B) is the same as the azeotropic mixture of methanol. Furthermore, phenol and other substances are further removed by distillation from the unevaporated bottoms liquid remaining in step (E2), followed by crystallization, thereby obtaining bisphenol A. Figure 10 The process (E1) can be completed by connecting with... Figure 3 The same method is used in step (B1) of the method for manufacturing bisphenol (B).

[0213] <Methods for manufacturing alkyl aryl carbonates>

[0214] This invention relates to a method for manufacturing alkyl aryl carbonates (hereinafter sometimes referred to as "method for manufacturing alkyl aryl carbonates of the present invention"), comprising: a decomposition step in which polycarbonate resin is decomposed in the presence of an aromatic monohydric alcohol, an aliphatic monohydric alcohol, and a catalyst; and an alkyl aryl carbonate recovery step in which the alkyl aryl carbonates generated by the decomposition of the aforementioned polycarbonate resin are recovered.

[0215] The method for manufacturing alkyl aryl carbonate of the present invention only requires that the polycarbonate resin be decomposed in a reaction solution containing polycarbonate resin, aromatic monohydric alcohol, aliphatic monohydric alcohol and catalyst in the decomposition step, and the reaction solution does not need to be in slurry form. Otherwise, it is the same as the decomposition method of the present invention.

[0216] The reaction solution can be in the form of a slurry, and the decomposition step can be a step of decomposing polycarbonate resin using the decomposition method of the present invention. That is, the method for manufacturing the alkyl aryl carbonate of the present invention can be configured to include: a decomposition step, in which the aforementioned polycarbonate resin is decomposed in a slurry-like reaction solution containing polycarbonate resin, an aromatic monohydric alcohol, an aliphatic monohydric alcohol, and a catalyst; and an alkyl aryl carbonate recovery step, in which the alkyl aryl carbonate generated in the aforementioned decomposition step is recovered. Alternatively, the method for manufacturing the alkyl aryl carbonate of the present invention can be configured to include: a preparation step, in which a slurry-like reaction solution containing polycarbonate resin, an aromatic monohydric alcohol, an aliphatic monohydric alcohol, and a catalyst is prepared; a decomposition reaction step, in which the aforementioned polycarbonate resin is decomposed in the slurry-like reaction solution prepared in the aforementioned preparation step; and an alkyl aryl carbonate recovery step, in which the alkyl aryl carbonate generated in the aforementioned decomposition reaction step is recovered.

[0217] By controlling the amount of aliphatic monohydric alcohol relative to polycarbonate resin, alkyl aryl carbonate can be generated as a decomposition product. The decomposition process is as described in the decomposition method of this invention.

[0218] The method for producing alkyl aryl carbonates of the present invention is suitable as a method for producing alkyl phenyl carbonates. That is, phenol is preferably used as the aromatic monohydric alcohol used in the decomposition of polycarbonate resins.

[0219] To manufacture alkyl aryl carbonates more efficiently, the molar ratio of the aforementioned aliphatic monohydric alcohol to 1 mole of the aforementioned polycarbonate resin repeating unit is preferably less than 2.0, and can be set to 1.95 or less, 1.9 or less, 1.85 or less, 1.8 or less, etc. Furthermore, from the viewpoint of manufacturing efficiency, the lower limit is preferably 0.1 or more, more preferably 0.5 or more, and even more preferably 1.0 or more.

[0220] <Alkyl Aryl Carbonate Recycling Process>

[0221] The recovery (separation, purification) of alkyl aryl carbonates can be carried out by conventional methods. For example, a method can be used to neutralize the reaction solution. Then, the neutralized organic phase is heated and / or distilled under reduced pressure. Distillation can be performed, for example, under reduced pressure to 0.1–50 kPa and / or heated to 100–200 °C.

[0222] Figure 11 , 12 A flowchart illustrating an example of a method for manufacturing the alkyl aryl carbonate of the present invention. Figure 11 , 12 In the manufacturing methods (F) and (G) of the alkyl aryl carbonate shown, phenol is used as an aromatic monohydric alcohol, methanol is used as an aliphatic monohydric alcohol, and bisphenol A type polycarbonate resin is used as a polycarbonate resin, as representative examples.

[0223] Figure 11 The method (F) for manufacturing alkyl aryl carbonate shown comprises: step (F1), decomposing polycarbonate resin in a slurry-like reaction solution containing bisphenol A type polycarbonate resin, phenol, methanol, and an alkali metal hydroxide as a catalyst; step (F2), neutralizing the reaction solution after step (F1) to obtain an organic phase containing bisphenol A, dimethyl carbonate, methyl phenyl carbonate, methanol, and phenol; and step (F3), distilling the organic phase obtained in step (F2) to obtain methyl phenyl carbonate.

[0224] Figure 11 The methyl phenyl carbonate obtained in process (F3) and Figure 6 The methylphenyl carbonate distilled in step (A3) of the bisphenol manufacturing method (A) is the same. In addition, the unevaporated bottom liquid remaining in step (F3) is further crystallized to obtain bisphenol A. Figure 11 The processes (F1) to (F2) can be performed by... Figure 2 The same method is used in steps (A1) to (A2) of the method for manufacturing bisphenol (A).

[0225] Furthermore, in the method (F) for producing alkyl aryl carbonates, an acid can be used as a catalyst, and a base is used for neutralization. In this case, the methyl phenyl carbonate obtained in step (F3) is the same as the methyl phenyl carbonate distilled in step (C3) of the method (C) for producing bisphenol.

[0226] Figure 12 The method (G) for manufacturing alkyl aryl carbonate shown comprises: step (G1), decomposing polycarbonate resin in a slurry-like reaction solution containing a bisphenol A type polycarbonate resin, phenol, methanol, and an alkylamine as a catalyst; and step (G2), distilling the reaction solution after step (G1) to obtain methyl phenyl carbonate.

[0227] Figure 12 The methylphenyl carbonate obtained in step (G2) of the method (G) for manufacturing dialkyl carbonate shown is... Figure 8 The methylphenyl carbonate distilled in step (B2) of the bisphenol manufacturing method (B) shown is the same. Furthermore, the unevaporated bottom liquid remaining from step (G2) is further crystallized to obtain bisphenol A. Figure 12 The process (G1) can be completed by connecting with... Figure 3 The same method is used in step (B1) of the method for manufacturing bisphenol (B).

[0228] It should be noted that the manufacturing methods (F) and (G) of alkyl aryl carbonate involve decomposing polycarbonate resin in a slurry-like reaction solution. The manufacturing methods of alkyl aryl carbonate of the present invention only require that polycarbonate resin can be decomposed in the presence of aromatic monohydric alcohols, aliphatic monohydric alcohols and catalysts, and do not need to be in a slurry-like reaction solution.

[0229] <Method for manufacturing diaryl carbonate of the present invention>

[0230] The method for manufacturing diaryl carbonate of the present invention involves using at least a portion of the raw materials obtained by the method for manufacturing dialkyl carbonate of the present invention (hereinafter sometimes referred to as "recycled dialkyl carbonate") or by the method for manufacturing alkylaryl carbonate of the present invention (hereinafter sometimes referred to as "recycled alkylaryl carbonate"), to manufacture diaryl carbonate. For example, the method for manufacturing diaryl carbonate of the present invention can be a method for manufacturing diphenyl carbonate.

[0231] Hereinafter, the method for manufacturing diaryl carbonate using recycled dialkyl carbonate will be referred to as "the method for manufacturing the first diaryl carbonate", and the method for manufacturing diaryl carbonate using recycled alkyl aryl carbonate will be referred to as "the method for manufacturing the second diaryl carbonate". Furthermore, both the "method for manufacturing the first diaryl carbonate" and the "method for manufacturing the second diaryl carbonate" will be collectively referred to as "the method for manufacturing diaryl carbonate of the present invention".

[0232] (Method for manufacturing diaryl carbonate)

[0233] The first method for manufacturing diaryl carbonate is a method for manufacturing diaryl carbonate using diaryl carbonate (recycled diaryl carbonate) obtained by the method for manufacturing diaryl carbonate of the present invention.

[0234] The method for manufacturing the first diaryl carbonate only requires using a dialkyl carbonate containing recycled dialkyl carbonate as a raw material. The manufacturing of diaryl carbonate can be carried out using known methods for manufacturing diaryl carbonate from dialkyl carbonate (e.g., Japanese Patent Application Publication No. 3-291257, etc.).

[0235] For example, diaryl carbonate can be manufactured by the following method: using dialkyl carbonate and aromatic monohydric alcohol as raw materials, a transesterification reaction is carried out to obtain alkylaryl carbonate (reaction formula (3a) below), and then the alkylaryl carbonate is subjected to a disproportionation reaction to obtain diaryl carbonate (reaction formula (3b) below).

[0236]

[0237] In equations (3a) and (3b), R7 Ar represents alkyl, and Ar represents aryl.

[0238] The aromatic monohydric alcohol (ArOH) that can be used in reaction formula (3a) is the same substance as the aromatic monohydric alcohol used in the decomposition reaction of the present invention. Phenol is preferably used in the above reaction formula (3a).

[0239] As catalysts used in reactions (3a) and (3b), known catalysts used in the manufacture of diaryl carbonates can be used. For example, organotitanium catalysts such as tetraphenoxytitanium can be used.

[0240] The dialkyl carbonate used as the raw material only needs to be at least partially recycled dialkyl carbonate. Recycled dialkyl carbonate can be used alone, or it can be used in combination with conventional dialkyl carbonates that are not recycled dialkyl carbonates. The amount of recycled dialkyl carbonate is not particularly limited. From an environmental perspective, the amount of recycled dialkyl carbonate in the raw material is preferably 50% by mass or more, with higher amounts preferred in the order of 70% by mass or more, 80% by mass or more, and 90% by mass or more.

[0241] (Method for manufacturing diaryl carbonate II)

[0242] The second diaryl carbonate manufacturing method is a method for manufacturing diaryl carbonate using alkyl aryl carbonate (regenerated alkyl aryl carbonate) obtained by the method of manufacturing alkyl aryl carbonate of the present invention.

[0243] The method for producing the second diaryl carbonate only requires the use of alkyl aryl carbonate esters containing recycled alkyl aryl carbonate esters as raw materials. The production of diaryl carbonate esters can be carried out using known methods for producing diaryl carbonate esters from alkyl aryl carbonate esters.

[0244] For example, diaryl carbonate can be obtained by reaction (3b) in the method for manufacturing the first diaryl carbonate.

[0245] The alkyl aryl carbonate raw material only needs to be at least partially recycled alkyl aryl carbonate. It can be used alone, or it can be used in combination with conventional alkyl aryl carbonates that are not recycled alkyl aryl carbonates. The amount of recycled alkyl aryl carbonate is not particularly limited. From an environmental perspective, the amount of recycled alkyl aryl carbonate in the raw material is preferably 50% by mass or more, with higher amounts preferred in the order of 70% by mass or more, 80% by mass or more, and 90% by mass or more.

[0246] The reaction of dialkyl carbonate and aromatic monohydric alcohol to obtain alkylaryl carbonate and aliphatic monohydric alcohol is an equilibrium reaction, with the equilibrium extremely biased towards the reactant system. Consequently, the reaction rate is slow. Therefore, it is preferable to manufacture diaryl carbonate using a method for producing a second diaryl carbonate that utilizes the alkylaryl carbonate produced by the method of the present invention.

[0247] <Method for manufacturing recycled polycarbonate resin of the present invention>

[0248] The method for manufacturing the recycled polycarbonate resin of the present invention is a method for manufacturing recycled polycarbonate resin using bisphenol raw materials containing bisphenol (recycled bisphenol) obtained by the method for manufacturing bisphenol of the present invention, or diaryl carbonate raw materials containing diaryl carbonate (recycled diaryl carbonate) obtained by the method for manufacturing diaryl carbonate of the present invention.

[0249] Hereinafter, the method for manufacturing recycled polycarbonate resin using bisphenol raw materials containing recycled bisphenol will be referred to as "the first method for manufacturing recycled polycarbonate resin", and the method for manufacturing recycled polycarbonate resin using diaryl carbonate raw materials containing recycled diaryl carbonate will be referred to as "the second method for manufacturing recycled polycarbonate resin". Furthermore, both the "first method for manufacturing recycled polycarbonate resin" and the "second method for manufacturing recycled polycarbonate resin" will be collectively referred to as "the method for manufacturing recycled polycarbonate resin of the present invention".

[0250] (Method for manufacturing the first recycled polycarbonate resin)

[0251] The first method for manufacturing recycled polycarbonate resin is a method for manufacturing recycled polycarbonate resin using a bisphenol raw material containing bisphenol (recycled bisphenol) obtained by the bisphenol manufacturing method of the present invention. The first method for manufacturing recycled polycarbonate resin utilizes a chemical recycling method in which recycled bisphenol, obtained by decomposing polycarbonate resin contained in waste plastics or the like into bisphenol as a monomer, is used as a raw material to manufacture polycarbonate resin.

[0252] The first method for manufacturing polycarbonate resin, besides using bisphenol raw material containing recycled bisphenol as bisphenol, can appropriately select a known polymerization method for polycarbonate resin. Polycarbonate resin is usually manufactured by polymerizing bisphenol with diester in the presence of a catalyst.

[0253] In the first method for manufacturing recycled polycarbonate resin, the recycled polycarbonate resin can be obtained, for example, by polymerizing a bisphenol raw material containing recycled bisphenol (bisphenol obtained by the bisphenol manufacturing method of the present invention) and a diester raw material.

[0254] For example, recycled polycarbonate resin can be manufactured by a method of transesterification reaction of a bisphenol raw material containing recycled bisphenol with a carbonate raw material such as diphenyl carbonate in the presence of an alkali metal compound and / or an alkaline earth metal compound.

[0255] Regenerated bisphenol can be used entirely as a bisphenol raw material, or it can be mixed with ordinary bisphenol (not regenerated bisphenol) and used as part of the bisphenol raw material. There is no particular limitation on the amount of regenerated bisphenol; amounts of 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, and 90% by mass or more are arbitrary. A higher proportion of regenerated bisphenol results in better environmental performance; therefore, from an environmental perspective, a higher amount of regenerated bisphenol relative to the bisphenol raw material is preferred.

[0256] Diaryl carbonate can be used as a raw material for dicarbonate. The diaryl carbonate may be configured to contain recycled diaryl carbonate or to use only conventional diaryl carbonate without recycled diaryl carbonate.

[0257] The above transesterification reaction can be carried out using a known method. An example of a method using diphenyl carbonate as a raw material for dicarbonate is described below.

[0258] In the first method for manufacturing recycled polycarbonate resin, diphenyl carbonate is preferably used in an excess amount relative to the bisphenol raw material. Regarding the amount of diphenyl carbonate used relative to the bisphenol raw material, a larger amount is preferred from the perspective of fewer terminal hydroxyl groups and excellent thermal stability of the polymer in the manufactured recycled polycarbonate resin; conversely, a smaller amount is preferred from the perspective of a fast transesterification reaction rate and ease of manufacturing recycled polycarbonate resin with the desired molecular weight. Based on these considerations, 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.

[0259] As a method of supplying raw materials, bisphenol raw materials and diphenyl carbonate can also be supplied in solid form, preferably by melting one or both and supplying them in a liquid state.

[0260] When producing recycled polycarbonate resin via the transesterification reaction of diphenyl carbonate and bisphenol raw materials, a transesterification catalyst is typically used. Alkali metal compounds and / or alkaline earth metal compounds are preferably used as this transesterification catalyst. Only one type can be used, or two or more can be used in any combination and ratio. Practically, alkali metal compounds are ideally used.

[0261] The amount of catalyst used relative to 1 mole of bisphenol raw material or diphenyl carbonate is typically 0.05 μmol or more, preferably 0.08 μmol or more, and more preferably 0.10 μmol or more. Additionally, it is typically 100 μmol or less, preferably 50 μmol or less, and more preferably 20 μmol or less.

[0262] By using the catalyst within the above-mentioned range, the polymerization activity required to produce recycled polycarbonate resin with the desired molecular weight can be easily obtained, and the polymer color is excellent. In addition, excessive polymer branching does not occur, and polycarbonate resin with excellent flowability during molding can be easily obtained.

[0263] When manufacturing recycled polycarbonate resin by the above method, it is preferable to continuously supply the two raw materials to the raw material mixing tank and continuously supply the resulting mixture and transesterification catalyst to the polymerization tank.

[0264] In the manufacture of recycled polycarbonate resin based on transesterification, the two raw materials are usually fed to a raw material mixing tank, stirred evenly, and then fed to a polymerization tank containing a catalyst to produce polymer.

[0265] (Method for manufacturing the second recycled polycarbonate resin)

[0266] The second method for manufacturing recycled polycarbonate resin is a method for manufacturing recycled polycarbonate resin using a diaryl carbonate raw material containing diaryl carbonate (recycled diaryl carbonate) obtained by the method for manufacturing diaryl carbonate of the present invention.

[0267] The second method for manufacturing recycled polycarbonate resin uses a diaryl carbonate raw material, which comprises a diaryl carbonate (recycled diaryl carbonate) produced by decomposing polycarbonate resin contained in waste plastics, etc., into dialkyl carbonate and / or alkyl aryl carbonate. As mentioned above, polycarbonate resin is typically manufactured by polymerizing a bisphenol raw material with a diester raw material in the presence of a catalyst. In addition to using a diaryl carbonate raw material containing recycled diaryl carbonate as the diester raw material, the second method for manufacturing polycarbonate resin can suitably employ any known polymerization method for polycarbonate resin.

[0268] Regenerated diaryl carbonate can be used entirely as a diaryl carbonate feedstock, or it can be mixed with conventional diaryl carbonate (not diaryl carbonate) and used as a fraction of the diaryl carbonate feedstock. The amount of recycled diaryl carbonate is not particularly limited and can 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. A higher proportion of recycled diaryl carbonate results in better environmental performance; therefore, from an environmental perspective, a higher amount of recycled diaryl carbonate relative to the diaryl carbonate feedstock is preferable.

[0269] Specifically, recycled polycarbonate resin can be obtained by polymerizing a diaryl carbonate raw material containing recycled diaryl carbonate (the recycled diaryl carbonate obtained by the method for manufacturing diaryl carbonate of the present invention) with a bisphenol raw material. Furthermore, the bisphenol raw material may contain recycled bisphenol, or it may use only conventional bisphenol without recycled bisphenol.

[0270] The polymerization method, the mixing ratio of raw materials, the amount of catalyst, and the supply method are the same as those in the manufacturing method of the first recycled polycarbonate resin. It should be noted that in the manufacturing method of the first recycled polycarbonate resin, a bisphenol raw material containing recycled bisphenol is used as the bisphenol raw material, but the bisphenol raw material used in the manufacturing method of the second recycled polycarbonate resin may contain recycled bisphenol raw material or may use ordinary bisphenol raw material that does not contain recycled bisphenol raw material.

[0271] (Recycled polycarbonate resins and their compositions)

[0272] The recycled polycarbonate resin obtained by the method for manufacturing recycled polycarbonate resin of the present invention can be used directly, or a recycled polycarbonate resin composition comprising unused polycarbonate resin and recycled polycarbonate resin can be used. The recycled polycarbonate resin composition can be obtained by mixing unused polycarbonate resin and recycled polycarbonate resin using a suitable, known mixing method, etc. When using a recycled polycarbonate resin composition comprising unused polycarbonate resin and recycled polycarbonate resin, the amount of recycled polycarbonate resin is not particularly limited; the higher the proportion of recycled polycarbonate resin, the better the environment. Therefore, from an environmental perspective, the amount of recycled polycarbonate resin relative to the recycled polycarbonate resin composition is preferably 50% by mass or more, and the higher the proportion, the more preferred, in the order of 70% by mass or more, 80% by mass or more, and 90% by mass or more.

[0273] The resulting recycled polycarbonate resin and composition can be molded into various molded products such as optical components and optical recording media, just like unused polycarbonate resin.

[0274] <Methods for manufacturing epoxy resin>

[0275] This invention relates to a method for manufacturing epoxy resins using bisphenol obtained by the bisphenol manufacturing method of this invention. Furthermore, the obtained epoxy resin can be further reacted with a polyhydroxy compound raw material to manufacture another epoxy resin.

[0276] Thus, the method for manufacturing the epoxy resin of the present invention is a method of manufacturing epoxy resin using at least a portion of the raw materials in the form of recycled bisphenol and / or epoxy resin manufactured using recycled bisphenol. The method for manufacturing the epoxy resin of the present invention is not particularly limited except that it uses recycled bisphenol (bisphenol obtained by the bisphenol manufacturing method of the present invention) and / or epoxy resin manufactured using recycled bisphenol as raw materials, and known epoxy resin manufacturing methods can be used. For example, as described below, recycled bisphenol can be used as at least a portion of the polyhydroxy compound raw material in manufacturing using a one-stage method, an oxidation method, or a two-stage method. The resulting epoxy resin can also be used as at least a portion of the epoxy resin raw material in manufacturing using a two-stage method.

[0277] It should be noted that "epoxy resin raw material" refers to the epoxy resin used as a raw material for the epoxy resin (hereinafter sometimes referred to as "recycled epoxy resin") obtained by the epoxy resin manufacturing method of the present invention. "Multi-hydroxy compound" is a general term for phenolic compounds with two or more members and alcohol compounds with two or more members, and "multi-hydroxy compound raw material" refers to multi-hydroxy compounds used as raw materials for recycled epoxy resin.

[0278] As a method for manufacturing the epoxy resin of the present invention, a one-stage method, an oxidation method, a two-stage method, etc., can be used.

[0279] The method for manufacturing epoxy resin based on a single-stage process involves reacting regenerated bisphenol (bisphenol obtained by the bisphenol manufacturing method of the present invention) with epoxy halopropane to obtain epoxy resin.

[0280] The method for manufacturing epoxy resin based on oxidation involves allylating regenerated bisphenols with allyl halides (allyl chloride, allyl bromide, etc.) followed by an oxidation reaction to obtain epoxy resin.

[0281] The two-stage epoxy resin manufacturing method is a method of reacting epoxy resin raw materials with polyhydroxy compound raw materials, wherein recycled bisphenol and / or epoxy resin manufactured using recycled bisphenol are used as raw materials.

[0282] The following describes the manufacturing methods of epoxy resins using the one-stage method, the oxidation method, and the two-stage method.

[0283] (A method for manufacturing epoxy resin based on a one-stage process)

[0284] There are no particular restrictions on the manufacturing method of epoxy resin based on the one-step process, as long as it is a known manufacturing method. The following is a detailed description.

[0285] In a one-step epoxy resin manufacturing method, a polyhydroxy compound other than regenerated bisphenol (hereinafter sometimes referred to as "other polyhydroxy compounds") can be used in combination with regenerated bisphenol. That is, the one-step epoxy resin manufacturing method is a method of obtaining epoxy resin by reacting a polyhydroxy compound raw material with an epoxy halide, and at least a portion of the polyhydroxy compound raw material can be regenerated bisphenol.

[0286] There is no particular limitation on the content of regenerated bisphenol in the polyhydroxy compound raw material. If the content of regenerated bisphenol is high, the environment is excellent. Therefore, 1 to 100% by mass is preferred, and 10 to 100% by mass is more preferred.

[0287] Here, "other polyhydroxy compounds" refers to all phenolic compounds with two or more members and alcohol compounds with two or more members, excluding regenerated bisphenol. In the one-step epoxy resin manufacturing method, "polyhydroxy compound raw materials" refers to all polyhydroxy compounds that combine regenerated bisphenol and other polyhydroxy compounds used as needed.

[0288] Examples of other polyhydroxy compounds include bisphenol A, tetramethylbisphenol A, bisphenol F, tetramethylbisphenol F, bisphenol S, bisphenol C, bisphenol AD, bisphenol AF, hydroquinone, resorcinol, methylresorcinol, biphenol, tetramethylbiphenol, dihydroxynaphthalene, dihydroxydiphenyl ether, thiodiphenols, phenolic varnish resins, cresol phenolic varnish resins, phenol aryl alkyl resins, biphenyl aryl alkyl resins, naphthol aryl alkyl resins, terpene phenolic resins, dicyclopentadiene phenolic resins, bisphenol A phenolic varnish resins, naphthol phenolic varnish resins, brominated bisphenol A, brominated phenolic varnish resins, and various other polyphenols. These compounds react with benzaldehyde and hydroxyl groups... Polyphenolic resins obtained by condensation reactions of various aldehydes such as benzaldehyde, crotonaldehyde, and glyoxal; polyphenolic resins obtained by condensation reactions of xylene resin and phenols; various phenolic resins such as co-condensation resins of heavy oil or asphalt with phenols and formaldehyde; chain aliphatic diols such as ethylene glycol, trimethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, 1,3-pentanediol, 1,4-pentanediol, 1,5-pentanediol, and 1,6-hexanediol; cyclic aliphatic diols such as cyclohexanediol and cyclodecanediol; and polyalkylene ether diols such as polyethylene ether diol, polyoxymethylene ether diol, and polypropylene ether diol.

[0289] During the reaction, the polyhydroxy compound raw material is dissolved in an epichlorohydrin to form a homogeneous solution. Epichlorohydrin or epibromopropane can typically be used as the epichlorohydrin, but epichlorohydrin is preferred in this invention.

[0290] The amount of epoxy halide is preferably 1 hydroxyl equivalent relative to the polyhydroxy compound raw material (all polyhydroxy compounds), typically equivalent to 1.0 to 14.0 equivalents, particularly 2.0 to 10.0 equivalents. When the amount of epoxy halide is above the lower limit mentioned above, it is easier to control the high molecular weight reaction, and the resulting epoxy resin can have an appropriate epoxy equivalent, which is therefore preferred. On the other hand, when the amount of epoxy halide is below the upper limit mentioned above, there is a tendency to improve production efficiency, which is also preferred.

[0291] Next, while stirring the above solution, an amount of alkali metal hydroxide, typically 0.1 to 3.0 equivalents, preferably 0.8 to 2.0 equivalents, relative to the hydroxyl group of the polyhydroxy compound raw material, is added in solid or aqueous form to initiate the reaction. When the amount of alkali metal hydroxide added is above the lower limit mentioned above, unreacted hydroxyl groups are less likely to react with the generated epoxy resin, making it easier to control the high molecular weight reaction, which is therefore preferred. Furthermore, when the amount of alkali metal hydroxide added is below the upper limit mentioned above, impurities are less likely to be generated due to side reactions, which is also preferred. Examples of alkali metal hydroxides used here are typically sodium hydroxide or potassium hydroxide.

[0292] The reaction can be carried out under normal or reduced pressure, and the reaction temperature is preferably 20–200°C, more preferably 40–150°C. When the reaction temperature is above the lower limit mentioned above, the reaction proceeds easily and is easy to control, therefore it is preferred. Furthermore, when the reaction temperature is below the upper limit mentioned above, side reactions are less likely to occur, and in particular, the polymer content is easily reduced, therefore it is preferred.

[0293] Furthermore, the reaction can be carried out simultaneously with dehydration as needed. This dehydration is achieved by azeotropically boiling the reaction mixture while maintaining a predetermined temperature, separating the condensate obtained by cooling the evaporated vapors into oil and water, and returning the dehydrated oil to the reaction system. For alkali metal hydroxides, to suppress rapid reactions, it is preferable to add them intermittently or continuously in small amounts over 0.1 to 24 hours, more preferably 0.5 to 10 hours. Adding alkali metal hydroxides at or above the lower limit of the above-mentioned timeframe prevents rapid reaction and facilitates temperature control, thus this is preferable. Adding alkali metal hydroxides at or below the upper limit of the above-mentioned timeframe facilitates reduction of polymer content, thus this is preferable.

[0294] After the reaction is complete, the insoluble byproduct salts can be removed by filtration, or by washing with water followed by heating and / or vacuum distillation to remove unreacted epoxy propane.

[0295] Alternatively, catalysts such as tetramethylammonium chloride, tetraethylammonium bromide, benzyl dimethylamine, tertiary amines such as 2,4,6-tris(dimethylaminomethyl)phenol, imidazoles such as 2-ethyl-4-methylimidazolium and 2-phenylimidazolium, phosphonium salts such as ethyltriphenylphosphonium iodide, and phosphines such as triphenylphosphine can also be used in this reaction.

[0296] Furthermore, inactive organic solvents such as alcohols like ethanol and isopropanol, ketones like acetone, methyl ethyl ketone and methyl isobutyl ketone, ethers like dioxane and ethylene glycol dimethyl ether, glycol ethers like methoxypropanol, and nonprotic polar solvents like dimethyl sulfoxide and dimethylformamide can also be used in this reaction.

[0297] Manufacturing of epoxy resins with reduced total chlorine content

[0298] If it is necessary to reduce the total chlorine content of the epoxy resin obtained as shown above, an epoxy resin with reduced total chlorine content can be produced by reacting it with an alkali.

[0299] Organic solvents used to dissolve epoxy resins can be used in the reaction with alkali. There are no particular restrictions on the organic solvent used in the reaction; however, ketone-based organic solvents are preferred from the perspectives of manufacturing efficiency, processability, and operability. Furthermore, from the viewpoint of further reducing the amount of hydrolyzable chlorine, aprotic polar solvents can be used.

[0300] Examples of ketone-based organic solvents include methyl ethyl ketone (MEK), methyl isobutyl ketone (MEK), and cyclohexanone. MEK is particularly preferred due to its effectiveness and ease of post-processing. These solvents can be used individually or in combination of two or more.

[0301] Examples of aprotic polar solvents include dimethyl sulfoxide, diethyl sulfoxide, dimethyl sulfone, sulfolane, dimethylformamide, dimethylacetamide, and hexamethylphosphoramide. These can be used individually or in combination of two or more. Among these aprotic polar solvents, dimethyl sulfoxide is preferred due to its ease of availability and superior performance.

[0302] The amount of solvent used is based on the concentration of epoxy resin in the liquid supplied during the alkali treatment, which is typically 1 to 95% by mass, and preferably 5 to 80% by mass.

[0303] As a base, a solid or solution of an alkali metal hydroxide can be used. Examples of alkali metal hydroxides include potassium hydroxide and sodium hydroxide, with sodium hydroxide being preferred. Alternatively, alkali metal hydroxides can be prepared by dissolving them in an organic solvent or water. It is preferable to use them in the form of a solution prepared by dissolving the alkali metal hydroxide in an aqueous solvent or an organic solvent.

[0304] The amount of alkali metal hydroxide used, calculated based on the solid content of the alkali metal hydroxide, is preferably 0.01 to 20.0 parts by weight or less relative to 100 parts by weight of epoxy resin. More preferably, it is 0.10 to 10.0 parts by weight. When the amount of alkali metal hydroxide used is below the above-mentioned lower limit, the effect of reducing the total chlorine content is low. On the other hand, when the amount of alkali metal hydroxide used is above the above-mentioned upper limit, more polymer is generated, thus reducing the yield.

[0305] The reaction temperature is preferably 20–200°C, more preferably 40–150°C, and the reaction time is preferably 0.1–24 hours, more preferably 0.5–10 hours.

[0306] After the reaction, excess alkali metal hydroxides and by-product salts are removed by washing with water, and the organic solvents are removed by heating and / or vacuum distillation and / or steam distillation.

[0307] (A method for manufacturing epoxy resin based on oxidation)

[0308] There are no particular restrictions on the manufacturing method of epoxy resin based on oxidation, as long as it is a known manufacturing method. For example, it can be carried out according to the methods described in Japanese Patent Application Publication No. 2011-225711, Japanese Patent Application Publication No. 2012-092247, and Japanese Patent Application Publication No. 2012-111858.

[0309] In the oxidation-based epoxy resin manufacturing method, similar to the one-step method, other polyhydroxy compounds besides regenerated bisphenol can be used in combination with the regenerated bisphenol. That is, the oxidation-based epoxy resin manufacturing method involves allylating a polyhydroxy compound raw material with an allyl halide followed by an oxidation reaction to obtain the epoxy resin. This method can employ at least a portion of the polyhydroxy compound raw material as regenerated bisphenol.

[0310] In the method for manufacturing epoxy resin based on oxidation, the "polyhydroxy compound raw material" refers to all polyhydroxy compounds that combine regenerated bisphenol and other polyhydroxy compounds used as needed. Examples of other polyhydroxy compounds include substances similar to those used in the one-step method. The content of regenerated bisphenol in the polyhydroxy compound raw material is not particularly limited; however, a high content of regenerated bisphenol results in better environmental performance, therefore 1 to 100% by mass is preferred, and 10 to 100% by mass is more preferred.

[0311] (A two-stage method for manufacturing epoxy resin)

[0312] There are no particular restrictions on the manufacturing method of epoxy resin based on the two-stage method, as long as it is a known manufacturing method. The following is a detailed description.

[0313] The two-stage epoxy resin manufacturing method includes a step of reacting epoxy resin raw materials with polyhydroxy compound raw materials. It can be a method in which at least a portion of the aforementioned epoxy resin raw materials is epoxy resin manufactured using recycled bisphenol, and / or a method in which at least a portion of the aforementioned polyhydroxy compound raw materials is recycled bisphenol.

[0314] That is, the method for manufacturing epoxy resin based on the two-stage process can be any of the following methods (i) to (iii).

[0315] Method (i): A method for reacting an epoxy resin other than an epoxy resin manufactured using recycled bisphenol with a polyhydroxy compound feedstock containing recycled bisphenol.

[0316] In method (i), the epoxy resin raw material is an epoxy resin other than that manufactured using recycled bisphenol. Additionally, the polyhydroxy compound raw material is a combination of recycled bisphenol and other polyhydroxy compounds used as needed.

[0317] Method (ii): A method for reacting an epoxy resin raw material containing an epoxy resin manufactured using recycled bisphenol with a polyhydroxy compound raw material containing recycled bisphenol.

[0318] In method (ii), the epoxy resin raw material is all epoxy resins made by combining epoxy resins manufactured using recycled bisphenol and other epoxy resins used as needed. Additionally, the polyhydroxy compound raw material is all polyhydroxy compounds made by combining recycled bisphenol and other polyhydroxy compounds used as needed.

[0319] Method (iii): A method for reacting an epoxy resin raw material containing an epoxy resin manufactured using recycled bisphenol with other polyhydroxy compounds besides recycled bisphenol.

[0320] In method (iii), the epoxy resin raw material is all epoxy resin made by combining epoxy resin manufactured using recycled bisphenol with other epoxy resins used as needed. Additionally, the polyhydroxy compound raw material is other polyhydroxy compounds besides recycled bisphenol.

[0321] The epoxy resins manufactured using recycled bisphenols in methods (ii) and (iii) can be obtained by methods for manufacturing epoxy resins based on a one-step process or an oxidation process. Alternatively, the epoxy resin obtained in method (i) can also be used. It should be noted that other epoxy resins besides those manufactured using recycled bisphenols are the same as those described later in the methods for manufacturing cured epoxy resins, and other polyhydroxy compounds are the same as those used in the one-step process.

[0322] In methods (i) and (ii), the content of regenerated bisphenol in the polyhydroxy compound containing regenerated bisphenol is not particularly limited. If the content of regenerated bisphenol is high, the environment is excellent. Therefore, 1 to 100% by mass is preferred, and 10 to 100% by mass is more preferred.

[0323] In addition, in methods (ii) and (iii), the content of epoxy resin made from recycled bisphenol in the epoxy resin raw material containing epoxy resin made from recycled bisphenol is not particularly limited. If the content of epoxy resin made from recycled bisphenol is high, the environment is excellent. Therefore, 1 to 100% by mass is preferred, and 10 to 100% by mass is more preferred.

[0324] In the two-stage reaction, the preferred ratio of epoxy resin raw material to polyhydroxy compound raw material is (epoxy group equivalent): (hydroxyl group equivalent) = 1:0.1 to 2.0. More preferably, it is 1:0.2 to 1.2. When the equivalent ratio is within the above range, it is easier to increase the molecular weight, and more epoxy group ends remain, which is therefore preferred.

[0325] Furthermore, a catalyst can be used in the two-stage reaction. Any catalyst can be used, as long as it is a compound with catalytic ability to react epoxy groups with phenolic or alcoholic hydroxyl groups. Examples include alkali metal compounds, organophosphorus compounds, tertiary amines, quaternary ammonium salts, cyclic amines, and imidazoles. Among these, quaternary ammonium salts are preferred. Additionally, only one catalyst can be used, or two or more catalysts can be used in combination. The amount of catalyst used is typically 0.001 to 10% by mass relative to the epoxy resin raw material.

[0326] Furthermore, in the two-stage reaction, a solvent can be used. Any solvent can be used as long as it dissolves the epoxy resin raw material. Examples include aromatic solvents, ketone solvents, amide solvents, and glycol ether solvents. Only one solvent can be used, or two or more can be used in combination. The resin concentration in the solvent is preferably 10–95% by mass, more preferably 20–80% by mass. Additionally, if a highly viscous product is generated during the reaction, more solvent can be added to continue the reaction. After the reaction is complete, the solvent can be removed as needed, or additional solvent can be added.

[0327] In the two-stage reaction, the reaction temperature is preferably 20–250°C, more preferably 50–200°C. When the reaction temperature is above the upper limit mentioned above, there is a concern that the generated epoxy resin may deteriorate. Furthermore, when the reaction temperature is below the lower limit mentioned above, the reaction may not proceed completely. Additionally, the reaction time is typically 0.1–24 hours, preferably 0.5–12 hours.

[0328] <Manufacturing Method of Epoxy Resin Cured Products>

[0329] This invention relates to a method for manufacturing an epoxy resin cured product, which involves curing an epoxy resin composition comprising an epoxy resin obtained by the epoxy resin manufacturing method of this invention and a curing agent to obtain an epoxy resin cured product. In the method for manufacturing an epoxy resin cured product of this invention, the epoxy resin obtained by the epoxy resin manufacturing method of this invention described above is mixed with a curing agent to obtain a composition comprising the epoxy resin and the curing agent (hereinafter, sometimes referred to as "epoxy resin composition"), and then the epoxy resin composition is cured to obtain an epoxy resin cured product.

[0330] In addition, other epoxy resins (hereinafter sometimes simply referred to as "other epoxy resins") other than those obtained by the epoxy resin manufacturing method of the present invention, curing agents, curing accelerators, inorganic fillers, coupling agents, etc., may be appropriately blended into the epoxy resin composition as needed.

[0331] The content of recycled epoxy resin in the epoxy resin composition is not particularly limited. A higher content of recycled epoxy resin results in better environmental performance; therefore, relative to 100 parts by weight of all epoxy resin components in the epoxy resin composition, the recycled epoxy resin is preferably 40 parts by weight or more, more preferably 60 parts by weight or more. When other epoxy resins are included, the recycled epoxy resin content can be set to 40-99 parts by weight, 60-99 parts by weight, etc., relative to 100 parts by weight of all epoxy resin components in the epoxy resin composition. It should be noted that "all epoxy resin components" refers to the total amount of epoxy resin contained in the epoxy resin composition, which is the sum of recycled epoxy resin and other epoxy resins used as needed.

[0332] (Curing agent)

[0333] In this invention, a curing agent refers to a substance that facilitates the crosslinking reaction between the epoxy groups of an epoxy resin and / or the chain length elongation reaction. It should be noted that, in this invention, even if referred to as a "curing accelerator," any substance that facilitates the crosslinking reaction between the epoxy groups of an epoxy resin and / or the chain length elongation reaction is generally considered a curing agent.

[0334] In the epoxy resin composition, the content of the curing agent is preferably 0.1 to 1000 parts by weight relative to 100 parts by weight of all epoxy resin components. More preferably, it is 500 parts by weight or less.

[0335] As a curing agent, all known curing agents commonly used as epoxy resin curing agents can be used without particular restrictions. Examples include phenolic curing agents, aliphatic amines, polyether amines, alicyclic amines, aromatic amines, amine curing agents, anhydride curing agents, amide curing agents, tertiary amines, and imidazoles. A single curing agent can be used, or two or more can be used in combination. When using two or more curing agents in combination, they can be pre-mixed to prepare a mixed curing agent before use, or the curing agent components can be added separately and mixed simultaneously when mixing the epoxy resin obtained by the epoxy resin manufacturing method of the present invention with the components of other epoxy resins.

[0336] [Phenolic curing agent]

[0337] Specific examples of phenolic curing agents include regenerated bisphenol, bisphenol A, tetramethylbisphenol A, bisphenol F, tetramethylbisphenol F, bisphenol C, bisphenol S, bisphenol AD, bisphenol AF, hydroquinone, resorcinol, methylresorcinol, biphenol, tetramethylbiphenol, dihydroxynaphthalene, dihydroxydiphenyl ether, thiodiphenols, phenolic varnish resins, cresol phenolic varnish resins, phenol aryl alkyl resins, biphenyl aryl alkyl resins, naphthol aryl alkyl resins, terpene phenolic resins, dicyclopentadiene phenolic resins, bisphenol A phenolic varnish resins, triphenol methane-type resins, naphthol phenolic varnish resins, brominated bisphenol A, and bromine. Various polyphenols, such as phenolic varnish resins, polyphenolic resins obtained through the condensation reaction of various phenols with benzaldehyde, hydroxybenzaldehyde, crotonaldehyde, glyoxal, and other aldehydes, polyphenolic resins obtained through the condensation reaction of xylene resin with phenols, co-condensation resins of heavy oil or asphalt with phenols and formaldehyde, phenol·benzaldehyde·benzyldimethyldimethoxy condensate, phenol·benzaldehyde·benzyldimethyldihalide condensate, phenol·benzaldehyde·4,4'-dimethoxybiphenyl condensate, phenol·benzaldehyde·4,4'-dihalobiphenyl condensate, and other phenolic resins.

[0338] These phenolic curing agents can be used alone, or two or more can be used in any combination and mixing ratio.

[0339] The amount of phenolic curing agent mixed in is preferably 0.1 to 1000 parts by weight, more preferably 500 parts by weight or less, relative to 100 parts by weight of all epoxy resin components in the epoxy resin composition.

[0340] [Amine-based curing agent]

[0341] Examples of amine-based curing agents (excluding tertiary amines) include aliphatic amines, polyether amines, alicyclic amines, and aromatic amines.

[0342] Examples of aliphatic amines include ethylenediamine, 1,3-diaminopropane, 1,4-diaminopropane, hexamethylenediamine, 2,5-dimethylhexamethylenediamine, trimethylhexamethylenediamine, diethylenetriamine, iminodipropylamine, bis(hexamethylene)triamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, N-hydroxyethylethylenediamine, and tetra(hydroxyethyl)ethylenediamine.

[0343] Examples of polyetheramines include triethylene glycol diamine, tetraethylene glycol diamine, diethylene glycol bis(propylamine), polyoxypropylene diamine, and polyoxypropylene triamine.

[0344] Examples of alicyclic amines include isophorone isodiamine, menthenediamine, 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.

[0345] Examples of aromatic amines include tetrachloro-p-phenylenediamine, m-phenylenediamine, p-phenylenediamine, m-phenylenediamine, o-phenylenediamine, p-phenylenediamine, 2,4-diaminoanisole, 2,4-toluenediamine, 2,4-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, 4,4'-diamino-1,2-diphenylethane, 2,4-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl sulfone, m-aminophenol, m-aminobenzylamine, benzyl dimethylamine, 2-(dimethylaminomethyl)phenol, triethanolamine, methylbenzylamine, α-(m-aminophenyl)ethylamine, α-(p-aminophenyl)ethylamine, diaminodiethyldimethyldiphenylmethane, and α,α'-bis(4-aminophenyl)-p-diisopropylbenzene.

[0346] The amine-based curing agents mentioned above can be used in combination or in any combination and mixing ratio, with only one type used.

[0347] The aforementioned amine-based curing agent is preferably used in a range of 0.1 to 2.0, based on the equivalent ratio of functional groups in the curing agent to the total number of epoxy groups in the epoxy resin component contained in the epoxy resin composition. More preferably, it is in a range of 0.8 to 1.2, based on the equivalent ratio. Within this range, unreacted epoxy groups and functional groups of the curing agent are less likely to remain, and are therefore preferred.

[0348] [Tertiary amine]

[0349] Examples of tertiary amines include 1,8-diazabicyclo(5,4,0)undecene-7, triethylenediamine, benzyldimethylamine, triethanolamine, dimethylaminoethanol, tris(dimethylaminomethyl)phenol, etc.

[0350] The tertiary amines mentioned above can be used in single-agent form or in combination of two or more in any combination and mixing ratio.

[0351] The aforementioned tertiary amine is preferably used in a manner that is in the range of 0.1 to 2.0, based on the equivalent ratio of functional groups in the curing agent to the total number of epoxy groups in the epoxy resin component contained in the epoxy resin composition. More preferably, it is in the range of 0.8 to 1.2, based on the equivalent ratio. When it is within this range, unreacted epoxy groups and functional groups of the curing agent are less likely to remain, and therefore it is preferred.

[0352] [Anhydride-based curing agent]

[0353] Examples of anhydride-based curing agents include anhydrides and modified anhydrides.

[0354] Examples of acid anhydrides include, for example, phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, benzophenone tetracarboxylic anhydride, dodecenyl succinic anhydride, polyadipic anhydride, polyazelic anhydride, polysedimentic anhydride, poly(ethyl octadecanoic acid) anhydride, poly(phenyl hexadecanoic acid) anhydride, tetrahydrophthalic anhydride, methyl tetrahydrophthalic anhydride, methyl hexahydrophthalic anhydride, hexahydrophthalic anhydride, methyl humic anhydride, trialkyl tetrahydrophthalic anhydride, and methyl Cyclohexene dicarboxylic anhydride, methylcyclohexene tetracarboxylic anhydride, ethylene glycol dipreptyltrimethyl ester dianhydride, chlorobrittle anhydride, nadic anhydride, methylnadic anhydride, 5-(2,5-dioxotetrahydro-3-furanyl)-3-methyl-3-cyclohexane-1,2-dicarboxylic anhydride, 3,4-dicarboxy-1,2,3,4-tetrahydro-1-naphthous succinic anhydride, 1-methyl-dicarboxy-1,2,3,4-tetrahydro-1-naphthous succinic anhydride, etc.

[0355] Examples of modified acid anhydrides include those derived by modifying the aforementioned acid anhydrides with glycols. Examples of glycols that can be used in the modification include alkylene glycols such as ethylene glycol, propylene glycol, and neopentyl glycol, as well as polyether glycols such as polyethylene glycol, polypropylene glycol, and polytetramethylene ether glycol. Furthermore, copolymers of two or more of these glycols and / or polyether glycols can also be used.

[0356] The anhydride-based curing agents mentioned above can be used in combination or in any combination and mixing amount.

[0357] When using an anhydride-based curing agent, it is preferable to use it in a range of 0.1 to 2.0, based on the equivalent ratio of the functional groups in the curing agent to the total number of epoxy groups in the epoxy resin component of the epoxy resin composition. More preferably, it is in a range of 0.8 to 1.2, based on the equivalent ratio. Within this range, unreacted epoxy groups and functional groups of the curing agent are less likely to remain, which is therefore preferable.

[0358] [Amide-based curing agent]

[0359] Examples of amide-based curing agents include dicyandiamide and its derivatives, and polyamide resins.

[0360] Amide-based curing agents can be used in single-component or mixed in any combination and ratio.

[0361] When using an amide-based curing agent, it is preferable to use the amide-based curing agent in a manner that the total amount of the epoxy resin component and the amide-based curing agent in the epoxy resin composition is 0.1 to 20% by mass.

[0362] [Imidazole derivatives]

[0363] Examples of imidazoles include 2-phenylimidazolium, 2-ethyl-4(5)-methylimidazolium, 2-phenyl-4-methylimidazolium, 1-benzyl-2-methylimidazolium, 1-benzyl-2-phenylimidazolium, 1-cyanoethyl-2-undecylimidazolium, 1-cyano-2-phenylimidazolium, 1-cyanoethyl-2-undecylimidazolium trimellitate, 1-cyanoethyl-2-phenylimidazolium trimellitate, and 2,4-diamino-6-[2'-methylimidazolium-( The following are examples of imidazole derivatives: 1')]-ethyl-triazine, 2,4-diamino-6-[2'-ethyl-4'-methylimidazolyl-(1')]-ethyl-triazine, 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-triazine isocyanuric acid adducts, 2-phenylimidazolium isocyanuric acid adducts, 2-phenyl-4,5-dihydroxymethylimidazolium, 2-phenyl-4-methyl-5-hydroxymethylimidazolium, and epoxy resin adducts with the above imidazole derivatives. It should be noted that imidazole derivatives have catalytic activity and are therefore usually classified as curing accelerators, but in this invention they are classified as curing agents.

[0364] The imidazoles mentioned above can be used in single-agent form or in combination or ratio of two or more types.

[0365] When using imidazoles, it is preferable to use them in such a way that the imidazoles account for 0.1 to 20% by mass relative to the total amount of all epoxy resin components and imidazoles in the epoxy resin composition.

[0366] [Other curing agents]

[0367] In addition to the aforementioned curing agents, other curing agents may be used in epoxy resin compositions. There are no particular limitations on the other curing agents that may be used in epoxy resin compositions; any substance known as a curing agent for epoxy resins may be used.

[0368] These other curing agents can be used in single-agent or in combination of two or more.

[0369] [Other epoxy resins]

[0370] The epoxy resin composition may contain epoxy resins other than those obtained by the epoxy resin manufacturing method of the present invention. By including other epoxy resins, various physical properties can be improved.

[0371] For other epoxy resins that can be used in the epoxy resin composition, epoxy resins other than those obtained by the epoxy resin manufacturing method of the present invention are all acceptable. Specific examples include bisphenol A type epoxy resin, bisphenol C type epoxy resin, triphenol methane type epoxy resin, anthracene type epoxy resin, phenol-modified xylene resin type epoxy resin, bisphenol cyclododecyl type epoxy resin, bisphenol diisopropylresorcinol type epoxy resin, bisphenol F type epoxy resin, bisphenol AD ​​type epoxy resin, bisphenol AF type epoxy resin, hydroquinone type epoxy resin, methyl hydroquinone type epoxy resin, dibutyl hydroquinone type epoxy resin, resorcinol type epoxy resin, methyl resorcinol type epoxy resin, biphenol type epoxy resin, tetramethyl biphenol type epoxy resin, tetramethyl bisphenol F type epoxy resin, dihydroxy diphenyl ether type epoxy resin, epoxy resin derived from thiodiphenols, dihydroxynaphthalene type epoxy resin, dihydroxy anthracene type epoxy resin, dihydroxy dihydroanthracene type epoxy resin, dicyclopentadiene type epoxy resin, and epoxy resin derived from dihydroxy Epoxy resins derived from benzoyl groups, phenolic varnish-type epoxy resins, cresol phenolic varnish-type epoxy resins, bisphenol A phenolic varnish-type epoxy resins, naphthol phenolic varnish-type epoxy resins, phenol aralkyl type epoxy resins, naphthol aralkyl type epoxy resins, biphenyl aralkyl type epoxy resins, terpene phenol type epoxy resins, dicyclopentadiene phenol type 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 asphalts with phenols and formaldehydes, epoxy resins derived from diaminodiphenylmethane, epoxy resins derived from aminophenol, epoxy resins derived from phenylenediamine, epoxy resins derived from methylhexahydrophthalic acid, epoxy resins derived from dimer acids, etc. These can be used in single-agent form or in combination or mixing ratios of two or more types.

[0372] When the epoxy resin composition includes the other epoxy resins mentioned above, their content is preferably 1 to 60 parts by weight, more preferably 40 parts by weight or less, relative to 100 parts by weight of all epoxy resin components in the composition.

[0373] (Curing accelerator)

[0374] The epoxy resin composition preferably contains a curing accelerator. By including a curing accelerator, it is possible to shorten the curing time, lower the curing temperature, and easily obtain the desired cured product.

[0375] There are no particular restrictions on curing accelerators. Specific examples include organophosphorus compounds, phosphorus compounds such as phosphonium salts, tetraphenylboron salts, organic acid dihydrazides, and boron halide amine complexes.

[0376] Examples of phosphorus compounds that can be used as curing accelerators include triphenylphosphine, diphenyl(p-tolyl)phosphine, tri(alkylphenyl)phosphine, tri(alkoxyphenyl)phosphine, tri(alkyl·alkoxyphenyl)phosphine, tri(dialkylphenyl)phosphine, tri(trialkylphenyl)phosphine, tri(tetraalkylphenyl)phosphine, tri(dialkoxyphenyl)phosphine, tri(trialkoxyphenyl)phosphine, tri(tetraalkoxyphenyl)phosphine, trialkylphosphine, dialkylarylphosphine, alkyldiarylphosphine, and other organophosphines, or complexes of these organophosphines with organoborons, and compounds formed by the addition of these organophosphines with quinone compounds such as maleic anhydride, 1,4-benzoquinone, 2,5-methylbenzoquinone, 1,4-naphthoquinone, 2,3-dimethylbenzoquinone, 2,6-dimethylbenzoquinone, 2,3-dimethoxy-5-methyl-1,4-benzoquinone, 2,3-dimethoxy-1,4-benzoquinone, phenyl-1,4-benzoquinone, and diazonylphenylmethane, etc.

[0377] Among the curing accelerators listed above, organophosphorus compounds and phosphonium salts are preferred, with organophosphorus compounds being the most preferred. Furthermore, the curing accelerator may use only one of the substances listed above, or it may use two or more substances in any combination and ratio.

[0378] The curing accelerator is preferably used in an amount ranging from 0.1 parts by weight to 20 parts by weight relative to 100 parts by weight of all epoxy resin components in the epoxy resin composition. When the content of the curing accelerator is at or above the lower limit mentioned above, a good curing promotion effect can be obtained; on the other hand, when it is at or below the upper limit mentioned above, the desired cured properties are easily obtained, and therefore it is preferred.

[0379] (Inorganic filler material)

[0380] Inorganic fillers can be incorporated into epoxy resin compositions. Examples of inorganic fillers include fused silica, crystalline silica, glass powder, alumina, calcium carbonate, calcium sulfate, talc, and boron nitride. Only one type of filler can be used, or two or more can be combined in any combination and mixing ratio. The preferred amount of inorganic filler is 10% to 95% by mass of the total epoxy resin composition.

[0381] (Mold release agent)

[0382] Release agents can be formulated into epoxy resin compositions. Examples of release agents include natural waxes such as carnauba wax, synthetic waxes such as polyethylene wax, higher fatty acids such as stearic acid and zinc stearate and their metal salts, and hydrocarbon-based release agents such as paraffin wax. Only one of these can be used, or two or more can be combined in any combination and mixing ratio.

[0383] The amount of release agent mixed in is preferably 0.001 to 10.0 parts by weight relative to 100 parts by weight of all epoxy resin components in the epoxy resin composition. When the amount of release agent is within the above range, it can maintain the curing characteristics and exhibit good release properties, and is therefore preferred.

[0384] [Coupled agent]

[0385] Coupling agents can be incorporated into epoxy resin compositions. Preferably, the coupling agent is used in combination with inorganic fillers. By incorporating the coupling agent, the adhesion between the epoxy resin matrix and the inorganic filler can be improved. Examples of coupling agents include silane coupling agents and titanate coupling agents.

[0386] Examples of silane coupling agents include epoxy silanes such as γ-epoxypropoxypropyltrimethoxysilane, γ-epoxypropoxypropyltriethoxysilane, 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-ureopropyltriethoxysilane; mercaptosilanes such as 3-mercaptopropyltrimethoxysilane; p-styryltrimethoxysilane; vinyltrichlorosilane; vinyltri(β-methoxyethoxy)silane; vinyltrimethoxysilane; vinyltriethoxysilane; and γ-methacryloyloxypropyltrimethoxysilane, as well as epoxy, amino, and vinyl polymeric silanes.

[0387] Examples of titanate coupling agents include isopropyl triisostearyl titanate, isopropyl tris(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.

[0388] These coupling agents can be used in single-agent form or in combination or ratio of two or more in any combination.

[0389] When a coupling agent is used in an epoxy resin composition, its mixing amount is preferably 0.001 to 10.0 parts by weight relative to 100 parts by weight of the total epoxy resin component. When the mixing amount of the coupling agent is at or above the lower limit mentioned above, the effect of improving the adhesion between the epoxy resin as a matrix and the inorganic filler material by mixing the coupling agent tends to be improved. On the other hand, when the mixing amount of the coupling agent is below the upper limit mentioned above, the coupling agent is less likely to ooze from the obtained cured product, which is therefore preferable.

[0390] (Other blending components)

[0391] Other components not mentioned above may be incorporated into the epoxy resin composition. Examples of other compounding components include flame retardants, plasticizers, reactive diluents, and pigments, which may be suitably compounded as needed. However, components other than those listed above may also be compounded.

[0392] Examples of flame retardants include halogenated flame retardants such as brominated epoxy resin and brominated phenolic resin, antimony compounds such as antimony trioxide, phosphorus-based flame retardants such as red phosphorus, phosphate esters, and phosphine, nitrogen-based flame retardants such as melamine derivatives, and inorganic flame retardants such as aluminum hydroxide and magnesium hydroxide.

[0393] (Curing method)

[0394] Cured epoxy resin products can be obtained by curing the epoxy resin composition. There are no particular limitations on the curing method; generally, cured products can be obtained through a heat-based thermosetting reaction. During the thermosetting reaction, the curing temperature is preferably selected appropriately according to the type of curing agent used. For example, when using a phenolic curing agent, the curing temperature is typically 80–250°C. Furthermore, the curing temperature can be lowered by adding a curing accelerator to these curing agents. The reaction time is preferably 0.01–20 hours. When the reaction time is above the lower limit mentioned above, the curing reaction tends to proceed more readily and fully, which is therefore preferred. On the other hand, when the reaction time is below the upper limit mentioned above, it is easier to reduce deterioration caused by heating and energy loss during heating, which is also preferred.

[0395] (use)

[0396] The epoxy resin cured product obtained by curing the epoxy resin composition has a low coefficient of linear expansion and can produce a cured product with excellent heat crack resistance.

[0397] Therefore, epoxy resin cured products can be effectively used in any application where these properties are required. For example, they can be used in the coatings industry, such as electrodeposited coatings for automobiles, heavy-duty anti-corrosion coatings for ships and bridges, and coatings for the inner surface of beverage cans; in the electrical and electronic fields, such as laminates, semiconductor sealing materials, insulating powder coatings, and coil impregnation; and in the fields of seismic reinforcement of bridges, concrete reinforcement, flooring materials for buildings, lining of water supply facilities, drainage and permeable paving, and adhesives for vehicles and aircraft in the civil engineering and construction adhesives industry.

[0398] The epoxy resin composition can be used after curing for the aforementioned purposes, or it can be cured during the manufacturing process of the aforementioned purposes.

[0399] Example

[0400] The present invention will be described in more detail below through examples and comparative examples, but the present invention is not limited to the following examples as long as it does not exceed its spirit.

[0401] [Raw Materials and Reagents]

[0402] The polycarbonate resin used is "NOVAREX (registered trademark) M7027BF" polycarbonate resin from Mitsubishi Chemical Engineering Plastics Co., Ltd.

[0403] Phenol, toluene, sodium hydroxide, p-toluenesulfonic acid, methanol, ethanol, n-butanol, triethylamine, acetonitrile, and cesium carbonate are reagents from FUJIFILM Wako Pure Chemical Corporation.

[0404] Diphenyl carbonate is a product manufactured by Mitsubishi Chemical Company.

[0405] Tetraphenoxytitanium is synthesized and used according to the following steps.

[0406] 200 g (2.1 mol) of phenol and 100 mL of toluene were added to a 500 mL three-necked flask equipped with a receiver and distillation tube, and nitrogen flow was used to purify the flask. The flask was then immersed in a 100 °C oil bath to obtain a homogeneous solution. 57 g (0.2 mol) of tetraisopropoxytitanium was added to the solution. The internal temperature at the bottom of the flask was maintained at 100 °C to begin the distillation of isopropanol. Subsequently, the internal temperature was slowly raised to 116 °C, allowing 80 mL of the distillate, which was a mixture of isopropanol and toluene, to be distilled out. 50 mL of hexane was added to the resulting residue, and the mixture was cooled to room temperature to allow crystallization. The precipitated red crystals were obtained by filtration and dried using 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 tetraphenoxytitanium.

[0407] [analyze]

[0408] The formation and purity of bisphenols were confirmed by high-performance liquid chromatography using the following steps and conditions.

[0409] • Apparatus: Shimadzu LC-2010A, Waters 5μm 150mm × 4.6mm ID

[0410] Method: Low-pressure gradient method

[0411] • Analysis temperature: 40℃

[0412] • Elution buffer composition:

[0413] A liquid acetonitrile

[0414] Solution B is an 85% phosphoric acid:water solution with a ratio of 1 mL:999 mL.

[0415] When the analysis time is 0 minutes, the eluent composition is A:B = 35:65 (volume ratio, the same below). When the analysis time is 0-5 minutes, the eluent composition is set to A:B = 35:65. Then, when the analysis time is 5-40 minutes, it is gradually changed to A:B = 90:10.

[0416] • Flow rate: 0.85 mL / min

[0417] • Detection wavelength: 280nm

[0418] The analysis of dimethyl carbonate, diethyl carbonate, and dibutyl carbonate was performed using gas chromatography under the following steps and conditions.

[0419] • Device: GC-2014 manufactured by Shimadzu Corporation

[0420] Agilent DB-10.530mm×30m 1.5μm

[0421] • Detection method: FID

[0422] • Vaporization chamber temperature: 230℃

[0423] • Detector temperature: 300℃

[0424] • During the analysis time of 0 to 5 minutes, maintain the column temperature at 50°C. During the analysis time of 5 to 30 minutes, slowly increase the column temperature to 280°C. During the analysis time of 30 to 40 minutes, maintain the column temperature at 280°C.

[0425] • Quantitative method: Internal standard method using biphenyl as an internal standard

[0426] [Viscosity-average molecular weight (Mv)]

[0427] For viscosity-average molecular weight (Mv), polycarbonate resin is dissolved in dichloromethane (concentration 6.0 g / L), and the specific viscosity (ηsp) at 20°C is measured using an Ubbelohde viscometer. The viscosity-average molecular weight (Mv) is then calculated using the following formula.

[0428] ηsp / C=[η](1+0.28ηsp)

[0429] [η] = 1.23 × 10 -4 Mv 0.83

[0430] [The melting color of bisphenol]

[0431] Regarding the melting color of bisphenol, the test tube "P-24" manufactured by Nippon Electric Chemical Nitrogen Co., Ltd. 20g of bisphenol was added to the solution and melted at 174℃ for 30 minutes. The Hassen color number was determined using an OME7700 manufactured by Nippon Denshoku Kogyo Co., Ltd.

[0432] [pH Measurement]

[0433] pH was measured using a pH meter “pH METER ES-73” manufactured by HORIBA, Ltd., on an aqueous phase taken from a flask at 25°C.

[0434] [Example 1]

[0435] (Process Breakdown)

[0436] In a jacketed, detachable flask equipped with a Dimro condenser, stirring blades, and a thermometer, under a nitrogen atmosphere and at room temperature, 80g of polycarbonate resin (the molecular weight of the repeating unit of polycarbonate resin is 254g / mol, therefore the number of moles of repeating units = 80g ÷ 254g / mol = 0.31 mol), 240g of phenol, 23g of methanol (23g ÷ 32g / mol = 0.72 mol, the molar ratio of methanol to 1 mole of repeating unit of polycarbonate resin = 0.72 mol ÷ 0.31 mol = 2.32), and 15g of triethylamine (15g ÷ 101g / mol = 0.15 mol, the molar ratio of triethylamine to 1 mole of repeating unit of polycarbonate resin = 0.15 mol ÷ 0.31 mol = 0.48) (the liquid volume is 80g + 240g + 23g + 15g = 358g).

[0437] Subsequently, the internal temperature was raised to 85°C. Undissolved polycarbonate resin (in slurry form) was observed in the reaction solution at 85°C. A homogeneous reaction solution was obtained by directly reacting at 85°C for 4 hours.

[0438] The composition of a portion of the obtained reaction solution was confirmed by high performance liquid chromatography, and the result confirmed that bisphenol A was generated at 19.5% by mass (the yield was 19.5 ÷ 100 × 358 g ÷ 228 g / mol ÷ 0.31 mol = 99 mol%).

[0439] In addition, the composition of a portion of the obtained reaction solution was confirmed by gas chromatography, and the result confirmed that 6.5% by mass of dimethyl carbonate was produced (the yield was 6.5 ÷ 100 × 358 g ÷ 90 g / mol ÷ 0.31 mol = 83 mol%).

[0440] Compared to 80g of polycarbonate resin, 15g of triethylamine was used, which is a small amount. Therefore, no amine odor was detected when a portion of the aforementioned reaction solution was taken out.

[0441] [Example 2]

[0442] In Example 1, instead of 15g of triethylamine, 32g of triethylamine was used (32g ÷ 101g / molar = 0.32 molar, molar ratio of triethylamine to 1 molar repeating unit of polycarbonate resin = 0.32 molar ÷ 0.31 molar = 1.03), otherwise, it was carried out in the same manner as in Example 1.

[0443] The composition of a portion of the obtained reaction solution was confirmed by high performance liquid chromatography, and the result confirmed that 18.9% by mass of bisphenol A was generated (the yield was 18.9 ÷ 100 × 375 g ÷ 228 g / mol ÷ 0.31 mol = 100 mol%).

[0444] In addition, the composition of a portion of the obtained reaction solution was confirmed by gas chromatography, and the result confirmed that 7.2% by mass of dimethyl carbonate was produced (the yield was 7.2 ÷ 100 × 375 g ÷ 90 g / mol ÷ 0.31 mol = 97 mol%).

[0445] The amount of triethylamine used was 32g, which was excessive compared to 80g of polycarbonate resin. Perhaps due to the strong interaction with phenol, which is an acidic substance, the amine odor when a portion of the aforementioned reaction solution was taken out was not a noticeable odor.

[0446] [Example 3]

[0447] In Example 1, instead of 15g of triethylamine, 63g of triethylamine was used (63g ÷ 101g / molar = 0.62 molar, molar ratio of triethylamine to 1 molar repeating unit of polycarbonate resin = 0.62 molar ÷ 0.31 molar = 2.00), otherwise, it was carried out in the same manner as in Example 1.

[0448] The composition of a portion of the obtained reaction solution was confirmed by high performance liquid chromatography, and the result confirmed that 17.4% by mass of bisphenol A was generated (the yield was 17.4 ÷ 100 × 406 g ÷ 228 g / mol ÷ 0.31 mol = 100 mol%).

[0449] In addition, the composition of a portion of the obtained reaction solution was confirmed by gas chromatography, and the result confirmed that 6.6% by mass of dimethyl carbonate was produced (the yield was 6.6 ÷ 100 × 406 g ÷ 90 g / mol ÷ 0.31 mol = 96 mol%).

[0450] The amount of triethylamine used was 63g, which was excessive compared to 80g of polycarbonate resin. Perhaps due to the strong interaction with phenol, which is an acidic substance, the amine odor when a portion of the aforementioned reaction solution was taken out was not a noticeable odor.

[0451] [Example 4]

[0452] In Example 1, instead of 15g of triethylamine, 110g of triethylamine was used (110g ÷ 101g / molar = 1.01 molar, molar ratio of triethylamine to 1 molar repeating unit of polycarbonate resin = 1.01 molar ÷ 0.31 molar = 3.26), otherwise, it was carried out in the same manner as in Example 1.

[0453] The composition of a portion of the obtained reaction solution was confirmed by high performance liquid chromatography, and the result confirmed that 15.5% by mass of bisphenol A was generated (the yield was 15.5 ÷ 100 × 453 g ÷ 228 g / mol ÷ 0.31 mol = 99 mol%).

[0454] In addition, the composition of a portion of the obtained reaction solution was confirmed by gas chromatography, and the result confirmed that 5.9% by mass of dimethyl carbonate was produced (the yield was 5.9 ÷ 100 × 453 g ÷ 90 g / mol ÷ 0.31 mol = 96 mol%).

[0455] 110g of triethylamine was used in excess of 80g of polycarbonate resin. Perhaps due to the strong interaction with phenol, which is an acidic substance, the amine odor when a portion of the aforementioned reaction solution was taken out was not as pronounced as in Comparative Example 2 described later.

[0456] [Example 5]

[0457] In Example 1, instead of 15g of triethylamine, 128g of triethylamine was used (128g ÷ 101g / molar = 1.27 molar, molar ratio of triethylamine to 1 molar repeating unit of polycarbonate resin = 1.27 molar ÷ 0.31 molar = 4.10), otherwise, it was carried out in the same manner as in Example 1.

[0458] The composition of a portion of the obtained reaction solution was confirmed by high performance liquid chromatography, and the result confirmed that bisphenol A was generated at 14.9% by mass (the yield was 14.9 ÷ 100 × 471 g ÷ 228 g / mol ÷ 0.31 mol = 99 mol%).

[0459] In addition, the composition of a portion of the obtained reaction solution was confirmed by gas chromatography, and the result confirmed that 5.8% by mass of dimethyl carbonate was produced (the yield was 5.8 ÷ 100 × 471 g ÷ 90 g / mol ÷ 0.31 mol = 98 mol%).

[0460] 128g of triethylamine was used in excess of 80g of polycarbonate resin. Perhaps due to the strong interaction with phenol, which is an acidic substance, the amine odor when a portion of the aforementioned reaction solution was taken out was not as pronounced as in Comparative Example 2 described later.

[0461] [Example 6]

[0462] In Example 1, 33g of ethanol (0.72 mol) was used instead of 23g of methanol, and otherwise the same procedure was followed as in Example 1.

[0463] The composition of a portion of the obtained reaction solution was confirmed by high performance liquid chromatography, and the result confirmed that 17.5% by mass of bisphenol A was generated (the yield was 17.5 ÷ 100 × 368 g ÷ 228 g / mol ÷ 0.31 mol = 91 mol%).

[0464] In addition, the composition of a portion of the obtained reaction solution was confirmed by gas chromatography, and the result confirmed that 8.7% by mass of diethyl carbonate was produced (the yield was 8.7 ÷ 100 × 368 g ÷ 118 g / mol ÷ 0.31 mol = 88 mol%).

[0465] [Example 7]

[0466] In Example 1, 53g (0.72 mol) of n-butanol was used instead of 23g of methanol, and otherwise the same procedure was followed as in Example 1.

[0467] The composition of a portion of the obtained reaction solution was confirmed by high performance liquid chromatography, and the result confirmed that 14.5% by mass of bisphenol A was generated (the yield was 14.5 ÷ 100 × 388 g ÷ 228 g / mol ÷ 0.31 mol = 80 mol%).

[0468] In addition, the composition of a portion of the obtained reaction solution was confirmed by gas chromatography, and the result confirmed that 10.7% by mass of dibutyl carbonate was produced (the yield was 10.7 ÷ 100 × 388 g ÷ 174 g / mol ÷ 0.31 mol = 77 mol%).

[0469] [Example 8]

[0470] In Example 1, instead of 15g of triethylamine, 2g of sodium hydroxide was used (2g ÷ 40g / mol = 0.05mol, the molar ratio of sodium hydroxide to 1 mole of repeating unit of polycarbonate resin = 0.05mol ÷ 0.31mol = 0.16), otherwise, it was carried out in the same manner as in Example 1.

[0471] The composition of a portion of the obtained reaction solution was confirmed by high performance liquid chromatography, which showed that bisphenol A was generated at 20.4% by mass (the yield was 20.4 ÷ 100 × 345 g ÷ 228 g / mol ÷ 0.31 mol = 100 mol%). The formation of dimethyl carbonate was also confirmed.

[0472] [Example 9]

[0473] In Example 1, instead of 15g of triethylamine, 16g of p-toluenesulfonic acid was added (16g ÷ 172g / mol = 0.09 mol, and the molar ratio of sodium hydroxide to 1 mole of repeating unit of polycarbonate resin = 0.09 mol ÷ 0.31 mol = 0.29). Otherwise, it was carried out in the same manner as in Example 1.

[0474] The composition of a portion of the obtained reaction solution was confirmed by high performance liquid chromatography, which showed that bisphenol A was produced at 10.7% by mass (yield of 10.7 ÷ 100 × 359 g ÷ 228 g / mol ÷ 0.31 mol = 54 mol%). The formation of dimethyl carbonate was also confirmed.

[0475] [Comparative Example 1]

[0476] In a jacketed, detachable flask equipped with a Dimro condenser, stirring blades, and a thermometer, under a nitrogen atmosphere and at room temperature, add 80 g of polycarbonate resin, 201 g of methanol (201 g ÷ 32 g / mol = 6.28 mol, the molar ratio of methanol to 1 mol repeating unit of polycarbonate resin = 6.28 mol ÷ 0.31 mol = 20.25), and 15 g of triethylamine. Phenol is not added.

[0477] Next, although the internal temperature was intended to be raised to 85°C, methanol reflux occurred around 64°C, so the reaction was continued under reflux. Although a 4-hour reaction was desired, the polycarbonate resin was found in the reaction solution as a solid component, confirming that it had not decomposed.

[0478] [Comparative Example 2]

[0479] In a jacketed, detachable flask equipped with a Dimro condenser, stirring blades, and a thermometer, under a nitrogen atmosphere and at room temperature, add 80 g of polycarbonate resin, 201 g of methanol, and 127 g of triethylamine (127 g ÷ 101 g / mol = 1.26 mol; molar ratio of triethylamine to 1 mole of repeating unit of polycarbonate resin = 1.26 mol ÷ 0.31 mol = 4.06). Phenol is not added.

[0480] Subsequently, the internal temperature was raised to 64°C. The reaction was then carried out directly at 64°C for 4 hours to obtain a homogeneous reaction solution.

[0481] A portion of the obtained reaction solution was analyzed using high-performance liquid chromatography (HPLC) to confirm its composition. The results showed that bisphenol A was produced at 17.3% by mass (yield of 17.3 ÷ 100 × 408 g ÷ 228 g / mol ÷ 0.31 mol = 100 mol%). Since 127 g of triethylamine was used relative to 80 g of polycarbonate resin, a large quantity was used; therefore, a distinct amine odor was detected when a portion of the obtained reaction solution was taken out.

[0482] [Comparative Example 3]

[0483] In Example 1, 23g of methanol was used instead of methanol, and no methanol was supplied at all. Otherwise, the same procedure as in Example 1 was followed.

[0484] The composition of a portion of the obtained reaction solution was confirmed by high performance liquid chromatography, and the result confirmed that 8.5% by mass of bisphenol A was generated (the yield was 8.5 ÷ 100 × 335 g ÷ 228 g / mol ÷ 0.31 mol = 40 mol%).

[0485] When a portion of the aforementioned reaction solution was removed, no amine odor was detected.

[0486] Table 1 summarizes the types of aromatic monohydric alcohols, aliphatic monohydric alcohols, and catalysts used in Examples 1-5 and Comparative Examples 1-3. Table 2 summarizes the bisphenol A (BPA) formation rate (%) and the amine odor after the reaction in Examples 1-5 and Comparative Examples 1-3. Table 2 confirms that even with a small amount of amine, the combined use of phenol and methanol results in a homogeneous solution after the reaction, thus enabling the decomposition of polycarbonate resin and suppressing amine odor. Furthermore, even with a large amount of amine, the combined use of phenol and methanol also suppresses odor compared to a methanol-only system.

[0487] [Table 1]

[0488]

[0489] [Table 2]

[0490]

[0491] Table 3 summarizes the types of aromatic monohydric alcohols, aliphatic monohydric alcohols, catalysts, and bisphenol A (BPA) formation rates for Examples 1, 6-9. According to Table 3, any catalyst, including alkali metal hydroxides, alkali metal carbonates, alkylamines, and acids, can decompose polycarbonate resin. Furthermore, it is shown that polycarbonate resin can be decomposed even by changing the type of aliphatic monohydric alcohol. In particular, it is shown that bisphenol A can be obtained with a high formation rate through a combination of phenol and methanol.

[0492] [Table 3]

[0493]

[0494] [Example 10]

[0495] (Bisphenol recovery process)

[0496] The reaction solution obtained in Example 1 was transferred to a distillation apparatus equipped with a thermometer, stirring blades, distillation tube, and pressure regulator. While observing the distillation amount, the internal temperature was slowly raised to 180°C, and the internal pressure was slowly reduced from atmospheric pressure to 20 kPa. The azeotropic mixture of methanol and dimethyl carbonate, triethylamine, and phenol were removed by distillation.

[0497] Subsequently, nitrogen gas was used to restore the pressure inside the flask, and the internal temperature was lowered to 80°C. 200g of toluene was added to obtain organic phase 1. Organic phase 1 was then washed five times with 50g of deionized water to obtain organic phase 2.

[0498] The obtained organic phase 2 was cooled to 20°C to obtain a slurry. The slurry was filtered to obtain a filter cake. The filter cake was dried using a rotary evaporator to obtain 30g of bisphenol A.

[0499] The purity of the obtained bisphenol A was 99.8% by mass, and the melting color was APHA192.

[0500] (Dimethyl carbonate recovery process)

[0501] An azeotropic mixture of methanol and dimethyl carbonate, which was removed by distillation in the bisphenol recovery process, was fed into a separatory funnel and water was added to separate the oil and water phases. The oil phase was recovered to obtain 17g of dimethyl carbonate.

[0502] [Example 11]

[0503] In a 45 mL glass reaction vessel equipped with a stirrer and distillation tube, 0.00 g (0.04 mol) of bisphenol A 1 obtained in Example 10, 9.95 g (0.05 mol) of diphenyl carbonate, and 18 μL of a 400 ppm cesium carbonate aqueous solution were added. The pressure in the glass reaction vessel was reduced to approximately 100 Pa, and then the process of restoring the pressure to atmospheric pressure with nitrogen was repeated three times to replace the interior of the reaction vessel with nitrogen. Subsequently, the reaction vessel was immersed in an oil bath at 220°C to dissolve the contents.

[0504] The agitator was set to rotate at 100 times per minute. While distilling off the phenol byproduct of the oligomerization reaction of bisphenol A and diphenyl carbonate in the reaction tank, the pressure in the reaction tank was reduced from 101.3 kPa to 13.3 kPa using an absolute pressure gauge over 40 minutes.

[0505] Next, the pressure inside the reaction vessel was maintained at 13.3 kPa, and the phenol was further removed by distillation while an ester exchange reaction was carried out for 80 minutes.

[0506] Subsequently, the external temperature of the reaction tank was raised to 290°C, and the pressure inside the reaction tank was reduced from 13.3 kPa to 399 Pa using an absolute pressure gauge over 40 minutes to remove the distilled phenol from the system.

[0507] Subsequently, the absolute pressure in the reaction tank was reduced to 30 Pa to carry out the polycondensation reaction. The polycondensation reaction was terminated when the agitator in the reaction tank reached a predetermined stirring power. The time from heating to 290°C until the end of polymerization was 120 minutes.

[0508] Next, the reaction tank was restored to 101.3 kPa using an absolute pressure gauge with nitrogen gas, and then pressurized to 0.2 MPa using a gauge pressure gauge. The polycarbonate resin was then removed from the reaction tank, yielding the polycarbonate resin. The viscosity-average molecular weight (Mv) of the obtained polycarbonate resin was 27,100.

[0509] [Example 12]

[0510] (Process Breakdown)

[0511] In a jacketed, detachable flask equipped with a Dimro condenser, stirring blades, and a thermometer, under a nitrogen atmosphere and at room temperature, 80g of polycarbonate resin (the molecular weight of the repeating unit of polycarbonate resin is 254g / mol, therefore the number of moles of repeating units = 80g ÷ 254g / mol = 0.31 mol), 240g of phenol, 1g of methanol (1g ÷ 32g / mol = 0.031 mol, the molar ratio of methanol to 1 mole of repeating unit of polycarbonate resin = 0.031 mol ÷ 0.31 mol = 0.1), and 0.3g of sodium hydroxide (0.3g ÷ 40g / mol = 7.5 mmol, the molar ratio of sodium hydroxide to 1 mole of repeating unit of polycarbonate resin = 7.5 mmol ÷ 0.31 mol = 0.02) (the liquid volume is 80g + 240g + 1g + 0.3g = 321g).

[0512] Subsequently, the internal temperature was raised to 85°C. Undissolved polycarbonate resin (in slurry form) could be observed in the reaction solution at 85°C. Maintaining the temperature at 85°C for 3 hours directly resulted in a homogeneous reaction solution.

[0513] A portion of the obtained reaction solution was analyzed by gas chromatography to confirm its composition, revealing the formation of 0.7% by mass of methyl phenyl carbonate (yield of 0.7 ÷ 100 × 321 g ÷ 152 g / mol ÷ 0.31 mol = 5 mol%). No dimethyl carbonate was observed to form. Additionally, the formation of bisphenol A was confirmed.

[0514] [Example 13]

[0515] In Example 12, instead of 1g of methanol, 17g of methanol was used (17g ÷ 32g / molar = 0.53 molar, the molar ratio of methanol to 1 molar repeating unit of polycarbonate resin = 0.53 molar ÷ 0.31 molar = 1.7), otherwise it was carried out in the same manner as Example 12 (liquid volume was 80g + 240g + 17g + 0.3g = 337g).

[0516] The composition of a portion of the obtained reaction solution was confirmed by high-performance liquid chromatography (HPLC). The results confirmed the formation of 3.7% by mass of methyl phenyl carbonate (yield of 3.7 ÷ 100 × 337 g ÷ 152 g / mol ÷ 0.31 mol = 26 mol%) and 1.9% by mass of dimethyl carbonate (yield of 1.9 ÷ 100 × 337 g ÷ 90 g / mol ÷ 0.31 mol = 23 mol%). Additionally, the formation of bisphenol A was confirmed.

[0517] [Example 14]

[0518] In Example 12, instead of 1g of methanol, 17g of methanol (17g ÷ 32g / mol = 0.53 mol, molar ratio of methanol to 1 mole of repeating unit of polycarbonate resin = 0.53 mol ÷ 0.31 mol = 1.7) was used; instead of 0.3g of sodium hydroxide, 4.8g of triethylamine (4.8g ÷ 101g / mol = 0.05 mol, molar ratio of triethylamine to 1 mole of repeating unit of polycarbonate resin = 0.05 mol ÷ 0.31 mol = 0.16) was used. Otherwise, the same procedure as in Example 12 was followed (liquid volume was 80g + 240g + 17g + 4.8g = 342g).

[0519] The composition of a portion of the obtained reaction solution was confirmed by high-performance liquid chromatography (HPLC). The results confirmed the formation of 10.2% by mass of methyl phenyl carbonate (yield of 10.2 ÷ 100 × 342 g ÷ 152 g / mol ÷ 0.31 mol = 74 mol%) and 1.6% by mass of dimethyl carbonate (yield of 1.6 ÷ 100 × 342 g ÷ 90 g / mol ÷ 0.31 mol = 20 mol%). Additionally, the formation of bisphenol A was confirmed.

[0520] [Example 15]

[0521] In Example 12, instead of 1g of methanol, 40g of methanol was used (40g ÷ 32g / molar = 1.25 molar, the molar ratio of methanol to 1 molar repeating unit of polycarbonate resin = 1.25 molar ÷ 0.31 molar = 4.0), otherwise it was carried out in the same manner as Example 12 (liquid volume was 80g + 240g + 40g + 0.3g = 360g).

[0522] The composition of a portion of the obtained reaction solution was confirmed by high-performance liquid chromatography (HPLC), and no methyl phenyl carbonate was found to be formed. Dimethyl carbonate was confirmed to have formed at 3.7% by mass (yield of 3.7 ÷ 100 × 360 g ÷ 90 g / mol ÷ 0.31 mol = 48 mol%). Additionally, bisphenol A was confirmed to have formed.

[0523] In Examples 12-15, the molar ratio of methanol to 1 mole of PC (polycarbonate resin), the type of catalyst used, and the amount of methylphenyl carbonate produced are summarized in Table 4. According to Table 4, a large amount of methylphenyl carbonate can be obtained when the molar ratio of methanol to 1 mole of polycarbonate resin is less than 2.

[0524] [Table 4]

[0525]

[0526] [Example 16]

[0527] In Example 12, instead of 1g of methanol, 43g of butanol was used (43g ÷ 74g / molar = 0.58 molar, the molar ratio of butanol to 1 molar repeating unit of polycarbonate resin = 0.58 molar ÷ 0.31 molar = 1.9), otherwise it was carried out in the same manner as Example 12 (liquid volume was 80g + 240g + 43g + 0.3g = 363g).

[0528] The composition of a portion of the obtained reaction solution was confirmed by high-performance liquid chromatography (HPLC). The results confirmed the formation of 8.4% by mass of butylphenyl carbonate (yield of 8.4 ÷ 100 × 363 g ÷ 194 g / mol ÷ 0.31 mol = 51 mol%) and 0.7% by mass of dibutyl carbonate (yield of 0.7 ÷ 100 × 363 g ÷ 174 g / mol ÷ 0.31 = 5 mol%). Additionally, the formation of bisphenol A was confirmed.

[0529] [Example 17]

[0530] In a jacketed, detachable flask equipped with a Dimro condenser, stirring blades, and a thermometer, under a nitrogen atmosphere and at room temperature, 200g of polycarbonate resin (the molecular weight of the repeating unit of polycarbonate resin is 254g / mol, therefore the number of moles of repeating units = 200g ÷ 254g / mol = 0.79 mol), 600g of phenol, 45g of methanol (45g ÷ 32g / mol = 1.41 mol, the molar ratio of methanol to 1 mole of repeating unit of polycarbonate resin = 1.41 mol ÷ 0.79 mol = 1.8), and 2.4g of sodium hydroxide (2.4g ÷ 40g / mol = 0.06 mol, the molar ratio of sodium hydroxide to 1 mole of repeating unit of polycarbonate resin = 0.06 mol ÷ 0.79 mol = 0.08) were added (the liquid volume is 200g + 600g + 45g + 2.4g = 847g).

[0531] Subsequently, the internal temperature was raised to 85°C. Undissolved polycarbonate resin (in slurry form) was observed in the reaction solution at 85°C. A homogeneous reaction solution was obtained by directly reacting at 85°C for 3 hours.

[0532] The composition of a portion of the obtained reaction solution was confirmed by gas chromatography, and the results showed that 4.2% by mass of methyl phenyl carbonate was formed (the yield is 4.2 ÷ 100 × 847 g ÷ 152 g / mol ÷ 0.79 mol = 30 mol%). Additionally, the formation of dimethyl carbonate and bisphenol A was also confirmed.

[0533] Add 10g of 10% hydrochloric acid to the obtained reaction solution to neutralize the sodium hydroxide and stop the reaction, thus obtaining a mixed solution.

[0534] After filtering, the resulting mixture was placed in a flask equipped with a pressure reducing device, a thermometer, and a distillation tube, and then immersed in an oil bath. Under normal pressure, the oil bath was set to 120°C to remove unreacted methanol, dimethyl carbonate, and water by distillation.

[0535] Subsequently, the pressure was set to 1 kPa, and the oil bath was heated to 160°C, thereby distilling out the phenol.

[0536] The oil bath temperature was then raised to 175°C, thereby obtaining 28g of methyl phenyl carbonate.

[0537] [Example 18]

[0538] 28 g of methyl phenyl carbonate and 1 g of tetraphenoxy titanium obtained in Example 17 were added to a flask equipped with a pressure reducing device, thermometer, and distillation tube, and then immersed in an oil bath at 40°C. The pressure was set to 1 kPa, and the reaction was carried out while the temperature was slowly increased to 185°C to distill off the dimethyl carbonate. Subsequently, the oil bath was set to 210°C to obtain 11 g of diphenyl carbonate.

[0539] [Example 19]

[0540] In a 45 mL glass reaction vessel equipped with a stirrer and distillation tube, 10.00 g (0.04 mol) of bisphenol A, 9.95 g (0.05 mol) of diphenyl carbonate obtained in Example 18, and 18 μL of a 400 ppm cesium carbonate aqueous solution were added. The pressure in the glass reaction vessel was reduced to approximately 100 Pa, and then the process of restoring the pressure to atmospheric pressure with nitrogen was repeated three times to replace the interior of the reaction vessel with nitrogen. Subsequently, the reaction vessel was immersed in an oil bath at 220°C to dissolve the contents.

[0541] The agitator was set to rotate at 100 times per minute. While distilling off the phenol byproduct of the oligomerization reaction of bisphenol A and diphenyl carbonate in the reaction tank, the pressure in the reaction tank was reduced from 101.3 kPa to 13.3 kPa using an absolute pressure gauge over 40 minutes.

[0542] Next, the pressure inside the reaction vessel was maintained at 13.3 kPa, and the phenol was further removed by distillation while an ester exchange reaction was carried out for 80 minutes.

[0543] Subsequently, the external temperature of the reaction tank was raised to 290°C, and the pressure inside the reaction tank was reduced from 13.3 kPa to 399 Pa using an absolute pressure gauge over 40 minutes to remove the distilled phenol from the system.

[0544] Subsequently, the absolute pressure in the reaction tank was reduced to 30 Pa to carry out the polycondensation reaction. The polycondensation reaction was terminated when the agitator in the reaction tank reached a predetermined stirring power. The time from heating to 290°C until the end of polymerization was 120 minutes.

[0545] Next, the reaction tank was restored to 101.3 kPa using an absolute pressure gauge with nitrogen gas, and then pressurized to 0.2 MPa using a gauge pressure gauge. The polycarbonate resin was then removed from the reaction tank, yielding the polycarbonate resin. The viscosity-average molecular weight (Mv) of the obtained polycarbonate resin was 25800.

[0546] Industrial availability

[0547] According to the decomposition method of the present invention, useful compounds such as bisphenol can be obtained from waste plastics through chemical recycling. These compounds can then be used to remanufacture polycarbonate resins, which is industrially useful.

Claims

1. A method for decomposing polycarbonate resin, wherein, The polycarbonate resin is decomposed in a slurry-like reaction solution containing polycarbonate resin, aromatic monohydric alcohol, aliphatic monohydric alcohol, and a catalyst. The catalyst is selected from any one of the following groups: alkali metal hydroxides, alkali metal carbonates, alkylamines, and acids. The aromatic monohydric alcohol is selected from any one of the group consisting of phenol, cresol, and xylenol. The aliphatic monohydric alcohol is selected from any one of the group consisting of methanol, ethanol and n-butanol.

2. A method for decomposing polycarbonate resin, comprising: The preparation process includes preparing a slurry-like reaction solution comprising polycarbonate resin, aromatic monohydric alcohol, aliphatic monohydric alcohol, and a catalyst; and The decomposition reaction step involves decomposing the polycarbonate resin in the slurry-like reaction solution prepared in the preparation step. The catalyst is selected from any one of the following groups: alkali metal hydroxides, alkali metal carbonates, alkylamines, and acids. The aromatic monohydric alcohol is selected from any one of the group consisting of phenol, cresol, and xylenol. The aliphatic monohydric alcohol is selected from any one of the group consisting of methanol, ethanol and n-butanol.

3. The method for decomposing polycarbonate resin according to claim 1 or 2, wherein, The alkylamine is represented by the following formula (I), In the formula, R A R represents an alkyl group having 1 to 3 carbon atoms. B ~R C Each can be independently represented by a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.

4. The method for decomposing polycarbonate resin according to claim 1 or 2, wherein, The alkylamine is a tertiary amine.

5. The method for decomposing polycarbonate resin according to claim 1 or 2, wherein, In the slurry-like reaction solution, the molar ratio of the alkylamine to the repeating unit 1 of the polycarbonate resin is 4.5 or less.

6. The method for decomposing polycarbonate resin according to claim 1 or 2, wherein, The alkali metal hydroxide is sodium hydroxide or potassium hydroxide.

7. The method for decomposing polycarbonate resin according to claim 1 or 2, wherein, The acid is any one selected from the group consisting of sulfuric acid, phosphoric acid, and sulfonic acid.

8. The method for decomposing polycarbonate resin according to claim 1 or 2, wherein, The molar ratio of the aliphatic monohydric alcohol to the aromatic monohydric alcohol is less than 0.

7.

9. The method for decomposing polycarbonate resin according to claim 1 or 2, wherein, The reaction temperature for decomposing the polycarbonate resin is below 120°C.

10. A method for manufacturing bisphenol, comprising: The decomposition step involves using the decomposition method for polycarbonate resin according to any one of claims 1 to 9 to decompose the polycarbonate resin; and The bisphenol recovery process recovers bisphenol generated through the decomposition of the polycarbonate resin.

11. The method for manufacturing bisphenol according to claim 10, wherein, The bisphenol is 2,2-bis(4-hydroxyphenyl)propane.

12. A method for manufacturing a dialkyl carbonate, comprising: The decomposition step involves using the decomposition method for polycarbonate resin according to any one of claims 1 to 9 to decompose the polycarbonate resin; and The dialkyl carbonate recovery process recovers the dialkyl carbonate generated from the decomposition of the polycarbonate resin. In the slurry-like reaction solution, the molar ratio of the aliphatic monohydric alcohol to the repeating unit 1 of the polycarbonate resin is 2.0 or more and 6.0 or less.

13. A method for manufacturing an alkyl aryl carbonate, comprising: The decomposition process of polycarbonate resin involves the decomposition of polycarbonate resin in the presence of aromatic monohydric alcohols, aliphatic monohydric alcohols, and a catalyst; and The alkyl aryl carbonate recovery process recovers the alkyl aryl carbonates generated from the decomposition of the polycarbonate. The catalyst is selected from any one of the following groups: alkali metal hydroxides, alkali metal carbonates, alkylamines, and acids. The aromatic monohydric alcohol is selected from any one of the group consisting of phenol, cresol, and xylenol. The aliphatic monohydric alcohol is selected from any one of the group consisting of methanol, ethanol, and n-butanol. The molar ratio of the aliphatic monohydric alcohol to the repeating unit 1 of the polycarbonate resin is 0.1 or more and less than 2.

0.

14. A method for manufacturing an alkyl aryl carbonate, comprising: The decomposition step involves using the decomposition method for polycarbonate resin according to any one of claims 1 to 9 to decompose the polycarbonate resin; and The alkyl aryl carbonate recovery process recovers the alkyl aryl carbonates generated during the decomposition of the polycarbonate resin. The molar ratio of the aliphatic monohydric alcohol to the repeating unit 1 of the polycarbonate resin is 0.1 or more and less than 2.

0.

15. The method for producing alkyl aryl carbonates according to claim 13 or 14, wherein, The aromatic monohydric alcohol is phenol. The alkyl aryl carbonate is an alkyl phenyl carbonate.

16. A method for manufacturing a diaryl carbonate, comprising: The process of obtaining dialkyl carbonate by the method for manufacturing dialkyl carbonate according to claim 12; and the process of manufacturing diaryl carbonate using the obtained dialkyl carbonate.

17. A method for manufacturing a diaryl carbonate, comprising: The process of obtaining alkyl aryl carbonate by the method of manufacturing alkyl aryl carbonate according to any one of claims 13 to 15; And the process of using the obtained alkyl aryl carbonate to manufacture diaryl carbonate.

18. A method for manufacturing recycled polycarbonate resin, comprising: The process of obtaining bisphenol by the method of manufacturing bisphenol according to claim 10 or 11; and the process of manufacturing recycled polycarbonate resin using bisphenol raw materials containing the obtained bisphenol.

19. A method for manufacturing recycled polycarbonate resin, comprising: The process of obtaining diaryl carbonate by the manufacturing method of diaryl carbonate according to claim 16 or 17; And the process of manufacturing recycled polycarbonate resin using diaryl carbonate raw materials containing the obtained diaryl carbonate.

20. A method for manufacturing an epoxy resin, comprising: The process of obtaining bisphenol by the method of manufacturing bisphenol according to claim 10 or 11; and the process of manufacturing epoxy resin using the obtained bisphenol.

21. The method for manufacturing epoxy resin according to claim 20, wherein, The epoxy resin is further reacted with the polyhydroxy compound raw material.

22. A method for manufacturing an epoxy resin cured product, comprising: The process of obtaining epoxy resin by the method of manufacturing epoxy resin according to claim 20 or 21; The process of curing the epoxy resin composition comprising the obtained epoxy resin and curing agent to obtain a cured epoxy resin product.

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