JP2023124421A - Method for producing bisphenol, method for producing recycled polycarbonate resin, method for producing epoxy resin and method for producing epoxy resin cured product - Google Patents

Abstract

To provide a method for producing bisphenol, in which polycarbonate resin is decomposed with high reactivity and bisphenol is produced, even under such a mild condition with small environmental loads, and a method for producing a recycled polycarbonate resin using the obtained bisphenol, and a method for producing an epoxy resin.SOLUTION: A method for producing bisphenol is provided in which polycarbonate resin is decomposed in the presence of alkyl ester, aliphatic alcohol and a catalyst. A method for producing recycled polycarbonate resin is provided in which recycled polycarbonate resin is produced using bisphenol raw material including bisphenol obtained by the method for producing the bisphenol. A method for producing epoxy resin is provided in which epoxy resin is produced using epoxy resin raw material including bisphenol obtained by the method for producing the bisphenol.SELECTED DRAWING: None

Description

The present invention relates to a method for producing bisphenol. More specifically, it relates to a method for producing bisphenol using decomposition of polycarbonate resin. Further, the present invention relates to a method for producing a recycled polycarbonate resin and a method for producing an epoxy resin using the bisphenol obtained by the method for producing bisphenol. Moreover, it is related with the manufacturing method of the epoxy-resin hardened|cured material using the epoxy resin obtained by the manufacturing method of the said epoxy resin.

Plastics are easy to use, highly durable, and inexpensive, so they are mass-produced not only in Japan but all over the world. Many of these plastics are used as "disposables" and some are not properly disposed of and end up in the environment. Specifically, plastic waste flows from rivers into the sea, where it is degraded by waves and ultraviolet rays and becomes less than 5 mm. These small pieces of plastic waste are called microplastics. Animals and fish accidentally ingest these microplastics. In this way, plastic waste has a tremendous impact on the ecosystem, and in recent years, it has become a problem all over the world as the marine plastic problem. 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.

As one of the recycling methods of polycarbonate resin, there is chemical recycling in which polycarbonate resin is chemically decomposed and returned to bisphenol for reuse, and alcoholysis is known as one of the decomposition methods of polycarbonate resin.

For example, in Patent Document 1, an aromatic polycarbonate dissolved in a monohydroxy compound other than methanol is catalytically transesterified with methanol in a distillation column to continuously form a dihydroxy compound and dimethyl carbonate. A method for systematically opening the ring is disclosed.

Further, in Patent Document 2, a specific tertiary amine is added as a catalyst to a solution in which waste plastic and monohydric alcohols or monohydric phenols are present, and the polycarbonate resin in the waste plastic is and a step of recovering the decomposition products as useful substances.

Non-Patent Document 1 discloses methanolysis of polylactic acid using ethyl acetate as a solvent and methyl carbonate (tetramethylammonium) as a catalyst. Further, methanolysis of a polycarbonate resin is disclosed using 2-methyltetrahydrofuran or dimethyl carbonate as a solvent and methyl carbonate (tetramethylammonium) as a catalyst.

JP-A-6-340591 JP-A-2004-51620

Green Chemistry, 2020, vol22, Issue 12, p3721-3726.

Aliphatic monoalcohols are usually used in decomposition methods utilizing alcoholysis of polycarbonate resins. However, in order to dissolve the polycarbonate resin and improve the decomposition rate, it is necessary to carry out the reaction under high pressure conditions at a high decomposition temperature. had to use.

Further, according to Example 1 of Patent Document 1, a polycarbonate resin is dissolved in phenol at 150° C. and decomposed by countercurrent contact with vapors composed of methanol and dimethyl carbonate. However, there is a problem that the control of the apparatus is complicated and the decomposition control of the polycarbonate resin is difficult.

Further, in the method of Patent Document 2, amine is used as a solvent and a catalyst because polycarbonate resin is difficult to dissolve in methanol. However, when the amount of amine is small, there is a problem that the reactivity is low and the reaction time is prolonged.

The present invention has been made in view of such circumstances, and utilizes a decomposition method capable of decomposing a polycarbonate resin with high reactivity even under mild conditions with a small environmental load, and bisphenol An object of the present invention is to provide a method for producing bisphenol. A further object of the present invention is to provide a method for producing a recycled polycarbonate resin and a method for producing an epoxy resin using the obtained bisphenol. Another object of the present invention is to provide a method for producing a cured epoxy resin using the epoxy resin obtained by the method for producing an epoxy resin.

The inventors of the present invention have made intensive studies to solve the above problems, and as a result, have found a decomposition method of decomposing a polycarbonate resin using both an alkyl ester and an aliphatic alcohol. In addition, a method for producing bisphenol was found using the decomposition method of the polycarbonate resin. Furthermore, a method for producing a recycled polycarbonate resin and a method for producing an epoxy resin using the obtained bisphenol have been found.
That is, the present invention relates to the following inventions.

式（Ｉ）中、Ｒ^Aは、炭素数１～３のアルキル基を表し、Ｒ^B～Ｒ^Cは、それぞれに独立に水素原子又は炭素数１～３のアルキル基を表す。

式（ＩＩ）中、Ｒ^D～Ｒ^Gは、それぞれに独立に水素原子又は炭素数１～３のアルキル基を表し、ｍは１～６の整数を表す。
＜５＞ 前記アルキルエステルが、メチルエステル、エチルエステル、ブチルエステル又はグリコールエステルである、前記＜１＞から＜４＞のいずれかに記載のビスフェノールの製造方法。
＜６＞ 前記ビスフェノールが、２，２－ビス（４－ヒドロキシフェニル）プロパンである、前記＜１＞から＜５＞のいずれかに記載のビスフェノールの製造方法。
＜７＞ 前記ポリカーボネート樹脂を分解させる分解温度が１５０℃以下である、前記＜１＞から＜６＞のいずれかに記載のビスフェノールの製造方法。
＜８＞ 前記アルキルエステルの炭素数が２以上、６以下である、前記＜１＞から＜７＞のいずれかに記載のビスフェノールの製造方法。
＜９＞ 前記脂肪族アルコールが、メタノール、エタノール、ブタノール及びエチレングリコールからなる群から選択されるいずれかである、前記＜１＞から＜８＞のいずれかに記載のビスフェノールの製造方法。
＜１０＞ 下記工程Ａ、工程Ｂ１及び工程Ｃ１を有する、前記＜１＞から＜９＞のいずれかに記載のビスフェノールの製造方法。
工程Ａ：前記ポリカーボネート樹脂を、前記アルキルエステル、前記脂肪族アルコール及び前記触媒の存在下で分解させて、ビスフェノールを含むポリカーボネート分解液を得る工程
工程Ｂ１：工程Ａで得られたポリカーボネート分解液を濃縮して、濃縮液を得る工程
工程Ｃ１：工程Ｂ１で得られた濃縮液に芳香族炭化水素を供給して晶析することでビスフェノールを析出させ、ビスフェノールを含むスラリーを得て、得られたスラリーを固液分離してビスフェノールを得る工程
＜１１＞ 下記工程Ａ、工程Ｂ２及び工程Ｃ２を有する、前記＜１＞から＜９＞のいずれかに記載のビスフェノールの製造方法。
工程Ａ：前記ポリカーボネート樹脂を、前記アルキルエステル、前記脂肪族アルコール及び前記触媒の存在下で分解させて、ビスフェノールを含むポリカーボネート分解液を得る工程
工程Ｂ２：工程Ａで得られたポリカーボネート分解液及び芳香族モノアルコールを含む溶液から前記アルキルエステル及び前記脂肪族アルコールを除去して、ビスフェノール及び芳香族モノアルコールを含む溶液を得る工程
工程Ｃ２：前記ビスフェノール及び芳香族モノアルコールを含む溶液からビスフェノールを回収する工程
＜１２＞ 前記＜１＞から＜１１＞のいずれかに記載のビスフェノールの製造方法を経てビスフェノールを得た後、該ビスフェノールを含むビスフェノール原料を用いて、再生ポリカーボネート樹脂を製造する、再生ポリカーボネート樹脂の製造方法。
＜１３＞ 前記＜１＞から＜１１＞のいずれかに記載のビスフェノールの製造方法を経てビスフェノールを得た後、該ビスフェノールを含む多価ヒドロキシ化合物原料を用いてエポキシ樹脂を製造する、エポキシ樹脂の製造方法。
＜１４＞ 前記＜１３＞に記載のエポキシ樹脂の製造方法を経てエポキシ樹脂を得た後、該エポキシ樹脂を含むエポキシ樹脂原料と多価ヒドロキシ化合物原料とを更に反応させ、エポキシ樹脂を製造する、エポキシ樹脂の製造方法。
＜１５＞ 前記＜１３＞又は＜１４＞に記載のエポキシ樹脂の製造方法を経てエポキシ樹脂を得て、該エポキシ樹脂と硬化剤を含むエポキシ樹脂組成物を得た後、該エポキシ樹脂組成物を硬化してエポキシ樹脂硬化物を得る、エポキシ樹脂硬化物の製造方法。 <1> A method for producing bisphenol, comprising decomposing a polycarbonate resin in the presence of an alkyl ester, an aliphatic alcohol and a catalyst.
<2> The catalyst according to <1>, wherein the catalyst is selected from the group consisting of alkali metal hydroxides, alkali metal alkoxides, alkali metal carbonates, alkali metal oxides, alkylamines and pyridines. A method for producing bisphenol.
<3> The alkali metal hydroxide is sodium hydroxide or potassium hydroxide, the alkali metal carbonate is sodium carbonate, potassium carbonate, sodium hydrogen carbonate or potassium hydrogen carbonate, and the alkali metal alkoxide is The method for producing bisphenol according to <2> above, wherein sodium phenoxide or sodium methoxide, and the alkali metal oxide is sodium oxide or potassium oxide.
<4> The method for producing bisphenol according to <2> above, wherein the alkylamine is represented by the following formula (I) or the following formula (II).

In formula (I), R ^A represents an alkyl group having 1 to 3 carbon atoms, and R ^B to R ^C each independently represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.

In formula (II), R ^D to R ^G each independently represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and m represents an integer of 1 to 6.
<5> The method for producing bisphenol according to any one of <1> to <4>, wherein the alkyl ester is methyl ester, ethyl ester, butyl ester or glycol ester.
<6> The method for producing bisphenol according to any one of <1> to <5>, wherein the bisphenol is 2,2-bis(4-hydroxyphenyl)propane.
<7> The method for producing bisphenol according to any one of <1> to <6>, wherein the decomposition temperature for decomposing the polycarbonate resin is 150°C or lower.
<8> The method for producing bisphenol according to any one of <1> to <7>, wherein the alkyl ester has 2 or more and 6 or less carbon atoms.
<9> The method for producing bisphenol according to any one of <1> to <8>, wherein the aliphatic alcohol is selected from the group consisting of methanol, ethanol, butanol and ethylene glycol.
<10> The method for producing bisphenol according to any one of <1> to <9>, comprising the following Step A, Step B1 and Step C1.
Step A: Step of decomposing the polycarbonate resin in the presence of the alkyl ester, the aliphatic alcohol and the catalyst to obtain a bisphenol-containing polycarbonate decomposition solution Step B1: Concentrating the polycarbonate decomposition solution obtained in Step A to obtain a concentrated liquid Step C1: An aromatic hydrocarbon is supplied to the concentrated liquid obtained in the step B1 and crystallized to precipitate bisphenol, to obtain a slurry containing bisphenol, and the resulting slurry <11> The method for producing bisphenol according to any one of <1> to <9>, comprising the following steps A, B2 and C2.
Step A: Step of decomposing the polycarbonate resin in the presence of the alkyl ester, the aliphatic alcohol and the catalyst to obtain a bisphenol-containing polycarbonate decomposition solution Step B2: The polycarbonate decomposition solution obtained in Step A and the aroma removing the alkyl ester and the aliphatic alcohol from the solution containing the aromatic monoalcohol to obtain a solution containing bisphenol and the aromatic monoalcohol Step C2: recovering the bisphenol from the solution containing the bisphenol and the aromatic monoalcohol Step <12> After obtaining bisphenol through the method for producing bisphenol according to any one of <1> to <11> above, a recycled polycarbonate resin is produced using a bisphenol raw material containing the bisphenol. manufacturing method.
<13> After obtaining bisphenol through the method for producing bisphenol according to any one of <1> to <11>, an epoxy resin is produced using a polyhydric hydroxy compound raw material containing the bisphenol. Production method.
<14> After the epoxy resin is obtained through the method for producing an epoxy resin according to <13>, an epoxy resin raw material containing the epoxy resin and a polyhydroxy compound raw material are further reacted to produce an epoxy resin. A method for producing an epoxy resin.
<15> An epoxy resin is obtained through the method for producing an epoxy resin according to <13> or <14>, an epoxy resin composition containing the epoxy resin and a curing agent is obtained, and then the epoxy resin composition is A method for producing a cured epoxy resin product by curing to obtain a cured epoxy resin product.

INDUSTRIAL APPLICABILITY According to the present invention, there is provided a method for producing bisphenol by utilizing a decomposition method capable of decomposing a polycarbonate resin with high reactivity even under mild conditions with little environmental load. . Furthermore, a method for producing a recycled polycarbonate resin and a method for producing an epoxy resin using the obtained bisphenol are provided. Also provided is a method for producing a cured epoxy resin using the epoxy resin obtained by the method for producing an epoxy resin.

The embodiments of the present invention will be described in detail below, but the description of the constituent elements described below is an example of the embodiments of the present invention, and the present invention does not exceed the gist thereof. is not limited to In addition, when the expression "~" is used in this specification, it is used as an expression including numerical values or physical property values before and after it.

<Method for producing bisphenol>
The present invention relates to a method for producing bisphenol by decomposing a polycarbonate resin in the presence of an alkyl ester, an aliphatic alcohol and a catalyst (hereinafter sometimes referred to as the "method for producing bisphenol of the present invention"). be.

The method for producing bisphenol of the present invention decomposes a polycarbonate resin in the presence of an alkyl ester, an aliphatic alcohol and a catalyst. As described above, Non-Patent Document 1 discloses methanolysis of polylactic acid in ethyl acetate. The OH group of methyl lactic acid produced by the decomposition of polylactic acid exhibits a weak interaction with the oxygen atom of the ester, and has a chemically stable structure. Hard to happen. On the other hand, when a polycarbonate resin is decomposed by a similar method, the OH group of bisphenol is highly acidic, so that ester exchange between the OH group of bisphenol and ethyl acetate easily occurs, and not only the desired bisphenol but also the esterified It can be easily imagined that bisphenol is produced and the recovery rate of bisphenol is lowered. Therefore, it has been thought that the use of alkyl esters as solvents for alcoholysis of polycarbonate resins is not preferable. However, the present inventors have found that bisphenol can be obtained at a high recovery rate by using an alkyl ester as a solvent and subjecting a polycarbonate resin to alcoholysis. In addition, even when general-purpose catalysts such as alkali metal hydroxides, alkali metal alkoxides, alkali metal carbonates, alkylamines, and pyridines are used, bisphenol can be converted by using alkyl esters and aliphatic alcohols together. It has been found that high recoveries can be obtained. By using an alkyl ester and an aliphatic alcohol together, the polycarbonate resin is alcoholyzed by the aliphatic alcohol, and ester decomposition by the alkyl ester can occur at the same time, so the polycarbonate resin decomposes even under mild conditions. It is thought that it will be easier to

(polycarbonate resin)
The polycarbonate resin used in the method for producing bisphenol of the present invention contains a polymer composition containing a carbonate bond (--O--C(=O)--O--). Specifically, the polycarbonate resin used in the method for producing bisphenol of the present invention contains repeating units derived from bisphenol represented by the general formula (1) (sometimes simply referred to as “repeating units”). containing polymers.

Substituents for R ¹ to R ⁴ each independently include a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, an aryl group, and the like. For example, hydrogen atom, fluoro group, chloro group, bromo group, iodo group, methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, t-butyl group, n- pentyl group, i-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, n-nonyl group, n-decyl group, n-undecyl group, n-dodecyl group, methoxy group, ethoxy group, n -propoxy group, i-propoxy group, n-butoxy group, i-butoxy group, t-butoxy group, n-pentyloxy group, i-pentyloxy group, n-hexyloxy group, n-heptyloxy group, n- octyloxy group, n-nonyloxy group, n-decyloxy group, n-undecyloxy group, n-dodecyloxy group, cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group , cyclododecyl group, benzyl group, phenyl group, tolyl group, 2,6-dimethylphenyl group and the like.

Substituents for R ⁵ and R ⁶ each independently include a hydrogen atom, an alkyl group, an alkoxy group, an aryl group, and the like. For example, hydrogen atom, methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, t-butyl group, n-pentyl group, i-pentyl group, n-hexyl group , n-heptyl group, n-octyl group, 2-ethylhexyl group, n-nonyl group, n-decyl group, n-undecyl group, n-dodecyl group, methoxy group, ethoxy group, n-propoxy group, i -propoxy group, n-butoxy group, i-butoxy group, t-butoxy group, n-pentyloxy group, i-pentyloxy group, n-hexyloxy group, n-heptyloxy group, n-octyloxy group, n -nonyloxy group, n-decyloxy group, n-undecyloxy group, n-dodecyloxy group, cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group, cyclododecyl group, benzyl group, phenyl group, tolyl group, 2,6-dimethylphenyl group and the like.

R ⁵ and R ⁶ may bond or bridge each other between the two groups to form a cycloalkylidene group. For example, cyclopropylidene, cyclobutylidene, cyclopentylidene, cyclohexylidene, 3,3,5-trimethylcyclohexylidene, cycloheptylidene, cyclooctylidene, cyclononylidene, cyclodecylidene, cycloundecylidene, cyclo dodecylidene, fluorenylidene, xanthonylidene, thioxanthonylidene and the like.

In the method for producing bisphenol of the present invention, among others, a polycarbonate resin (bisphenol A type polycarbonate resin) in which R ¹ to R ⁴ in the above general formula (1) are hydrogen atoms and R ⁵ and R ⁶ are methyl groups, It is preferable to use it as a raw material.

In general formula (1), n is not particularly limited, but is, for example, 2-1000.

As the polycarbonate resin which is the raw material for the method for producing bisphenol of the present invention, not only polycarbonate resin alone but also compositions containing resins other than polycarbonate resin such as copolymers and polymer alloys may be used. Examples of compositions containing resins other than polycarbonate resins include polycarbonate/polyester copolymers, polycarbonate/polyester alloys, polycarbonate/polyarylate copolymers, and polycarbonate/polyarylate alloys. When a composition containing a resin other than a polycarbonate resin is used, a composition containing a polycarbonate resin as a main component (containing 50% by mass or more of the polycarbonate resin in the composition) can be suitably used.

Moreover, polycarbonate resin can be used by mixing two or more different polycarbonate resins. A polycarbonate resin alone may be simply called polycarbonate.

From the viewpoint of chemical recycling, the polycarbonate resin contained in waste plastics is preferable as the polycarbonate resin. Polycarbonate resins are molded and used for various molded articles such as optical members such as headlamps and optical recording media such as optical discs. As the waste plastics containing polycarbonate resins, leftover materials, defective products, used molded products, and the like in molding polycarbonate resins into these molded products can be used.

Waste plastics can be appropriately washed, crushed, pulverized, or otherwise used. Methods for crushing waste plastics include coarse crushing to 20 cm or less using a jaw crusher or orbital crusher, medium crushing to 1 cm or less using an orbital crusher, cone crusher, or mill, or using a mill. It is a pulverization or the like that crushes to 1 mm or less, and it is sufficient if it can be reduced to a size that can be supplied to the decomposition tank. If the waste plastic is thin plastic such as CD or DVD, it can be shredded using a shredder or the like and supplied to the decomposition tank. In addition, other resins such as copolymers and polymer alloys, and portions formed of components other than the polycarbonate resin, such as the layers on the front and back surfaces of optical discs, may be removed in advance before use.

(alkyl ester)
One of the characteristics of the method for producing bisphenol of the present invention is to use an alkyl ester. Alkyl esters are reaction products of carboxylic acids and fatty alcohols. Examples of alkyl esters include monoalkyl esters, dialkyl esters, alkylene glycol alkyl esters, and the like.

Preferred alkyl esters are methyl esters, ethyl esters, butyl esters and glycol esters. A methyl ester is a compound having a structure of "--(C=O)--O--CH ₃ " in its molecule. Ethyl ester is a compound having a structure of "--(C=O)--O--C ₂ H ₅ " in its molecule. Butyl ester is a compound having a structure of "--(C=O)--O--C ₄ H ₉ " in its molecule. A glycol ester is a compound having a structure of "-(C=O)-O-(CH ₂ ) _x -O-(X is 1 to 10)" in its molecule.

For example, alkyl esters represented by formulas (a1) to (a3) can be used.

R ^a —(C═O)—OR ^b (a1)
In formula (a1), R ^a represents a hydrogen atom or an alkyl group. R ^b represents an alkyl group, preferably a methyl group, an ethyl group or a butyl group.

R ^c —O—(C═O)—R ^d —(C═O)—O—R ^e (a2)
In formula (a2), R ^c and R ^e each independently represent an alkyl group, preferably a methyl group, an ethyl group or a butyl group. ^Rd represents an alkylene group.

R ^f —(C═O)—OR ^g —O—(C═O)—R ^h (a3)
In formula (a3), R ^f and R ^h each independently represent a hydrogen atom or an alkyl group. R ^g represents an alkylene group.

The alkyl ester is preferably an alkyl ester having 2 to 6 carbon atoms, and examples thereof include monoalkyl esters having 2 to 6 carbon atoms, dialkyl esters having 5 or 6 carbon atoms, alkylene glycol alkyl esters having 4 to 6 carbon atoms, and the like.

Examples of monoalkyl esters having 2 to 6 carbon atoms include those in formula (a1) in which the total number of carbon atoms of R ^a and R ^b is 1 to 5. Specifically, monomethyl esters such as methyl formate, methyl acetate, methyl propionate, methyl butyrate, and methyl valerate; monoethyl esters such as ethyl formate, ethyl acetate, ethyl propionate, and ethyl butyrate; propyl formate, propyl acetate, monopropyl esters such as propyl propionate; monobutyl esters such as butyl formate and butyl acetate; and monopentyl esters such as pentyl formate.

Examples of dialkyl esters having 5 or 6 carbon atoms include those in which the total number of carbon atoms of R ^c , R ^d and R ^e is 3 or 4 in formula (a2). Specific examples include dimethyl esters such as dimethyl malonate, dimethyl methylmalonate and dimethyl succinate; and methyl ethyl esters such as methyl ethyl malonate.

The alkylene glycol alkyl ester having 4 to 6 carbon atoms includes, for example, those represented by formula (a3) in which the total number of carbon atoms of R ^f , R ^g and R ^h is 2 to 4. Specific examples include glycol esters such as ethylene diformate, methylene diacetate, and ethylene diacetate.

If the amount of alkyl ester used relative to the amount of polycarbonate resin used is small, the amount of solid (polycarbonate resin) relative to liquid increases, resulting in an increase in slurry concentration, which tends to result in poor mixing. Therefore, the molar ratio of the alkyl ester to 1 mol of the repeating unit of the polycarbonate resin (that is, the repeating unit represented by the general formula (1)) ((mass of the alkyl ester used [g]/molecular weight of the alkyl ester [g/ mol])/(mass of polycarbonate resin to be used [g]/molecular weight of repeating unit [g/mol])) is preferably 0.01 or more, more preferably 0.03 or more. In addition, when the amount of alkyl ester used relative to the polycarbonate resin used is large, the production efficiency tends to deteriorate. Therefore, the molar ratio of the alkyl ester to 1 mol of the repeating unit of the polycarbonate resin is preferably 100 or less, more preferably 70 or less, and even more preferably 50 or less.

(fatty alcohol)
One of the characteristics of the method for producing bisphenol of the present invention is the use of an aliphatic alcohol. Fatty alcohols can be aliphatic monoalcohols or glycols.

Aliphatic monoalcohols include methanol, ethanol, n-propanol, i-propanol, n-butanol, i-butanol, t-butanol, n-pentanol, i-pentanol, n-hexanol, n-heptanol, n- -octanol, n-nonanol, n-decanol, n-undecanol, n-dodecanol and the like.

Glycols include ethylene glycol, propylene glycol and the like.

Among them, the aliphatic alcohol is preferably an alcohol having 1 to 5 carbon atoms, more preferably one selected from the group consisting of methanol, ethanol, butanol and ethylene glycol.

If the amount of the aliphatic alcohol to be used is small relative to the polycarbonate resin to be used, the polycarbonate resin will be difficult to decompose, or the rate of decomposition will decrease, resulting in a longer decomposition time and a tendency to deteriorate efficiency. Therefore, the molar ratio of OH in the aliphatic alcohol to 1 mol of the repeating unit of the polycarbonate resin ((mass of the aliphatic alcohol used [g] × number of OH / molecular weight of the aliphatic alcohol [g / mol]) / (used The mass [g] of the polycarbonate resin to be used/molecular weight [g/mol] of the repeating unit)) is preferably 0.1 or more, more preferably 0.5 or more, and still more preferably 1.0 or more. Moreover, if the amount of the aliphatic alcohol used relative to the polycarbonate resin used is large, the production efficiency tends to deteriorate. Therefore, the molar ratio of OH in the aliphatic alcohol to 1 mol of the repeating unit of the polycarbonate resin is preferably 6.0 or less, more preferably 5.5 or less, and even more preferably 5.0 or less.

Decomposition of the polycarbonate resin can be controlled by adjusting the amount of the aliphatic alcohol and the reaction time. When the structure of the decomposition product to be obtained is controlled by the amount of the aliphatic alcohol, in order to efficiently produce the dialkyl carbonate, the molar ratio of OH in the aliphatic alcohol to 1 mol of the repeating unit of the polycarbonate resin is , is preferably 2.0 or more, more preferably 2.1 or more, and even more preferably 2.2 or more.

In addition, the molar ratio of OH in the aliphatic alcohol used to the alkyl ester used (number of moles of aliphatic alcohol used × number of OH / number of moles of alkyl ester used) is preferably 0.01 or more, and 0 0.05 or more is more preferred. The molar ratio is preferably 1.0 or less, more preferably 0.95 or less, more preferably 0.90 or less, and more preferably 0.85 or less. If the molar ratio of OH in the aliphatic alcohol used to the alkyl ester used is small, the polycarbonate resin will be difficult to decompose, or the decomposition rate will decrease and the decomposition time will be prolonged. Further, when the molar ratio is large, separation of the aliphatic alcohol and the alkyl ester becomes complicated when recovering the alkyl ester.

(catalyst)
One of the characteristics of the method for producing bisphenol of the present invention is that it further uses a catalyst. Any catalyst selected from the group consisting of alkali metal hydroxides, alkali metal alkoxides, alkali metal carbonates, alkali metal oxides, alkylamines and pyridines may be used as long as it can promote decomposition of the polycarbonate resin. is preferred.

[Alkali metal hydroxide]
In the present invention, an alkali metal hydroxide is a salt of an alkali metal ion (M ⁺ ) and a hydroxide ion (OH ^- ), and is a compound represented by MOH (M represents an alkali metal atom). be. Sodium hydroxide or potassium hydroxide is preferred as the alkali metal hydroxide.

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

[Alkali metal alkoxide]
In the present invention, an alkali metal alkoxide is a salt of an alkali metal ion (M ⁺ ) and an aliphatic or aromatic alkoxide, and is a compound represented by the following formula (2).
MOR ^H Formula (2)
In formula (2), M represents an alkali metal atom, preferably sodium or potassium. R ^H represents an alkyl group or an aryl group, preferably an alkyl group having 1 to 5 carbon atoms or a phenyl group.
More preferred alkali metal alkoxides are sodium phenoxide, sodium methoxide, sodium ethoxide, potassium phenoxide, potassium methoxide, potassium ethoxide and potassium t-butoxide.

If the amount of alkali metal alkoxide used relative to the polycarbonate resin used is small, the decomposition rate will be slow, the decomposition time will be prolonged, and the efficiency will tend to deteriorate. Therefore, the molar ratio of the alkali metal alkoxide to 1 mol of the repeating unit of the polycarbonate resin ((mass of the alkali metal alkoxide used [g] / molecular weight of the alkali metal alkoxide [g / mol]) / (mass of the polycarbonate resin used [g ]/molecular weight of repeating unit [g/mol])) is preferably 0.0001 or more, more preferably 0.0005 or more, and still more preferably 0.001 or more. For example, it can be 0.001 or more, or 0.01 or more. If the amount of alkali metal alkoxide used relative to the polycarbonate resin used is large, the amount of acid required for neutralization after decomposition tends to increase, resulting in a decrease in production efficiency. Therefore, the molar ratio of the alkali metal alkoxide to 1 mol of the repeating unit of the polycarbonate resin is preferably 1 or less, more preferably 0.9 or less, and even more preferably 0.8 or less.

[Alkali metal carbonate]
In the present invention, an alkali metal carbonate is a salt of an alkali metal ion (M ⁺ ) and a carbonate ion (CO ₃ ^2- ), and M ₂ CO ₃ or MHCO ₃ (M represents an alkali metal atom). is the compound represented. The alkali metal carbonate is preferably sodium carbonate, potassium carbonate, sodium hydrogencarbonate or potassium hydrogencarbonate, more preferably sodium carbonate or potassium carbonate.

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

[Alkali metal oxide]
Alkali metal oxides include sodium oxide, potassium oxide, and the like.

If the amount of the alkali metal oxide to be used is small relative to the polycarbonate resin to be used, the decomposition rate will be slow, the decomposition time will be prolonged, and the efficiency will tend to deteriorate. Therefore, the molar ratio of the alkali metal oxide to 1 mol of the repeating unit of the polycarbonate resin ((mass of the alkali metal oxide used [g] / molecular weight of the alkali metal oxide [g / mol]) / (the amount of the polycarbonate resin used Mass [g]/molecular weight of repeating unit of polycarbonate resin [g/mol])) is preferably 0.0001 or more, more preferably 0.0005 or more, and still more preferably 0.001 or more. For example, it can be 0.001 or more, or 0.01 or more. If the amount of alkali metal oxide used relative to the polycarbonate resin used is large, the amount of acid required for neutralization after decomposition tends to increase, resulting in a decrease in production efficiency. Therefore, the molar ratio of the alkali metal oxide to 1 mol of the repeating unit of the polycarbonate resin is preferably 1 or less, more preferably 0.9 or less, and even more preferably 0.8 or less.

[Alkylamine]
In the present invention, an alkylamine is a compound having an amine structure in which at least one hydrogen atom of ammonia is substituted with an alkyl group. The alkylamine preferably has a boiling point of 200°C or lower, more preferably 160°C or lower. If it is such a boiling point, it can be removed together with the alkyl ester by reducing pressure and/or heating. On the other hand, if the boiling point is too low, the alkylamine may volatilize during the decomposition reaction and the decomposition rate may decrease.

Alkylamines are preferably alkylmonoamines or alkyldiamines.

Among alkylamines, monoalkylmonoamine, which is a primary amine, reacts with the carbonate-bonded portion of the polycarbonate resin to generate isocyanate, and is more preferably a dialkylmonoamine, which is a secondary amine, or a trialkylmonoamine, which is a tertiary amine. . A dialkylmonoamine, which is a secondary amine, reacts with the carbonate-bonded portion of the polycarbonate resin to form a tetraalkylurea, and is more preferably a trialkylmonoamine, which is a tertiary amine.

The alkylamine is preferably an alkylmonoamine represented by general formula (I).

In general formula (I), R ^A represents an alkyl group having 1 to 3 carbon atoms, and R ^B to R ^C each independently represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.
R ^A is preferably a methyl group, ethyl group, n-propyl group, or i-propyl group, and R ^B to R ^C are each independently a hydrogen atom, a methyl group, an ethyl group, an n-propyl group, or i -Propyl groups are preferred.

Specific examples of alkylamines represented by formula (I) include methylamine, ethylamine, propylamine, dimethylamine, diethylamine, trimethylamine and triethylamine.

The alkylamine is preferably an alkyldiamine represented by general formula (II).

In general formula (II), R ^D to R ^G each independently represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and m represents an integer of 1 to 6.
R ^D to R ^G are each independently preferably a methyl group, an ethyl group, an n-propyl group or an i-propyl group.

Specific examples of alkylamines represented by formula (II) include ethylenediamine, trimethylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, N-methylethylenediamine, N,N'-dimethylethylenediamine, N,N '-dimethyltrimethylenediamine, N,N,N',N'-tetramethylethylenediamine, N,N'-diethylethylenediamine, N,N,N',N'-tetraethylethylenediamine, 1,3-diaminopropane, N -methyl-1,3-diaminopropane, N,N'-dimethyl-1,3-diaminopropane, N,N,N',N'-tetramethyl-1,3-diaminopropane and the like.

If the amount of alkylamine to be used is small relative to the polycarbonate resin to be used, the decomposition rate will be slow, the decomposition time will be prolonged, and the efficiency will tend to deteriorate. Therefore, the molar ratio of N of the amino group of the alkylamine to 1 mol of the repeating unit of the polycarbonate resin ((mass of the alkylamine used [g] x number of N of the amino group/molecular weight of the alkylamine [g/mol])/ (mass [g] of polycarbonate resin used/molecular weight [g/mol] of repeating unit)) is preferably 0.0005 or more, more preferably 0.0007 or more, and still more preferably 0.001 or more. For example, it can be 0.01 or more, or 0.1 or more. If the amount of alkylamine used relative to the polycarbonate resin used is large, the amine odor is more likely to occur, and dialkyl carbonate is less likely to be produced. Therefore, the molar ratio of N of the amino group of the alkylamine to 1 mol of the repeating unit of the polycarbonate resin is preferably 4.5 or less, 4.0 or less, 3.0 or less, 2.0 or less, 1.0 or less, 0 0.9 or less, and 0.8 or less, the smaller the order, the more preferable.

[pyridine]
In the present invention, pyridine may be unsubstituted or may have a substituent such as a methyl group or a hydroxyl group. Preferred is unsubstituted pyridine.

If the amount of pyridine to be used is small relative to the polycarbonate resin to be used, the decomposition rate will be slow, the decomposition time will be prolonged, and the efficiency will tend to deteriorate. Therefore, the molar ratio of pyridine to 1 mol of repeating units of the polycarbonate resin ((mass of pyridine used [g] / molecular weight of pyridine [g / mol]) / (mass of polycarbonate resin used [g] / repetition of polycarbonate resin The unit molecular weight [g/mol])) is preferably 0.0005 or more, more preferably 0.0007 or more, and still more preferably 0.001 or more. For example, it can be 0.01 or more, or 0.1 or more. If the amount of pyridine used relative to the polycarbonate resin used is too large, odor is more likely to occur, and dialkyl carbonates and condensates are less likely to form. Therefore, the molar ratio of pyridine to 1 mol of the repeating unit of the polycarbonate resin is preferably 4.5 or less, 4.0 or less, 3.0 or less, 2.0 or less, 1.0 or less, 0.9 or less, 0.9 or less. The smaller the number in the order of 8 or less, the more preferable.

(Reaction solution)
The prepared reaction liquid contains a polycarbonate resin, an alkyl ester, an aliphatic alcohol and a catalyst. The reaction is preferably carried out in a slurry-like solution in which the polycarbonate resin is dispersed in a liquid component containing an alkyl ester and an aliphatic alcohol. The slurry concentration in the reaction liquid (mass of solid content in reaction liquid/mass of reaction liquid) is preferably 0.01 or more, more preferably 0.05 or more. Moreover, 0.5 or less is preferable and 0.4 or less is more preferable. If the slurry concentration (concentration of solids) is too low, the decomposition efficiency will decrease, and if the slurry concentration is too high, poor mixing will occur.

The liquid components in the reaction solution to be prepared are mainly composed of alkyl esters and aliphatic alcohols, and the total mass of alkyl esters and aliphatic alcohols with respect to the mass of all liquid components is 0.8 or more or 0.8. 9 or more, 0.95 or more, and the like.

The total mass of the polycarbonate resin, the alkyl ester, the aliphatic alcohol and the catalyst with respect to the mass of the reaction solution can be 0.9 or more, 0.95 or more, 0.98 or more, or 0.99 or more. Also, the reaction liquid may be composed of a polycarbonate resin, an alkyl ester, an aliphatic alcohol and a catalyst.

When trying to obtain a dialkyl carbonate together with bisphenol, if the reaction solution contains water, the resulting dialkyl carbonate is likely to be decomposed. Therefore, the content of water in the reaction solution (mass of water/mass of reaction solution) is usually 0.005 or less. The content of water in the reaction solution is preferably 0.001 or less, more preferably 0.0005 or less.

(Preparation of reaction solution)
Preparation of the reaction solution is preferably carried out at 10° C. or higher, more preferably at 20° C. or higher. Also, the reaction solution is preferably prepared at 40° C. or lower, more preferably at 35° C. or lower. If the temperature during preparation of the reaction solution is too low, depending on the type of alkyl ester, solidification is likely to occur, which may result in poor mixing or difficulty in uniform mixing. Also, if the temperature during preparation of the reaction solution is too high, depending on the type of catalyst, it may easily volatilize, making it difficult to prepare the reaction solution at a predetermined concentration or to control the decomposition reaction.

The mixing order of polycarbonate resin, alkyl ester, aliphatic alcohol and catalyst is not particularly limited, for example, alkyl ester, aliphatic alcohol and catalyst may be sequentially supplied to polycarbonate resin, or alkyl ester may be supplied with polycarbonate resin, Fatty alcohol and catalyst may be fed sequentially. The polycarbonate resin is preferably fed to the reactor after the alkyl ester and/or the aliphatic alcohol, as this allows for more uniform mixing.

(decomposition reaction)
Due to the presence of alkyl esters, aliphatic alcohols and catalysts, the carbonate bond portion of the polycarbonate resin is cleaved and decomposition occurs. As a result, decomposition products such as bisphenol and dialkyl carbonate are produced. By controlling the amounts of the alkyl ester and the aliphatic alcohol and the reaction time, the decomposition reaction can be controlled such that bisphenol and dialkyl carbonate are preferentially produced.

In addition, the concentration of the polycarbonate resin and the temperature during the preparation of the reaction solution are controlled so that the decomposition reaction does not proceed during the preparation of the reaction solution (during the mixing of the polycarbonate resin, the alkyl ester, the aliphatic alcohol and the catalyst). The reaction solution preparation step and the decomposition reaction step may be clearly separated, but the reaction solution adjustment step and the decomposition step do not necessarily need to be clearly separated. A decomposition reaction of the polycarbonate resin proceeds during the preparation of the reaction liquid, and a part of the polycarbonate resin may be decomposed. By partially decomposing the polycarbonate resin during the preparation of the reaction solution, the decomposition reaction can proceed more efficiently.

The decomposition reaction may be carried out under normal pressure or under pressure, but is preferably carried out under normal pressure because the reaction proceeds sufficiently even under normal pressure.

(reaction temperature)
From the preparation of the reaction solution to the termination of the decomposition reaction, the temperature may be the same as the temperature during the preparation of the reaction solution, but after the reaction solution is prepared (after mixing the polycarbonate resin, alkyl ester, aliphatic alcohol and catalyst). It is preferable to raise the temperature to a predetermined reaction temperature immediately. If the temperature during preparation of the reaction solution is too high, it may become difficult to control the decomposition reaction. By raising the temperature of the reaction solution after preparation, the decomposition reaction can proceed stably, which is preferable.

The reaction temperature (the decomposition temperature at which the polycarbonate is decomposed) is appropriately selected according to the type of alkyl ester and the reaction time. stops. In addition, when the temperature is low, the alkyl ester solidifies or the solvolysis becomes difficult to proceed, resulting in a decrease in the reaction rate, which prolongs the time required for decomposition. For these reasons, the reaction temperature is preferably 60° C. or higher, and more preferably 70° C. or higher, 75° C. or higher, and 80° C. or higher in this order. In addition, 150° C. or less is preferable, and the smaller numerical values are more preferable in the order of 120° C. or less, 110° C. or less, 100° C. or less, and 95° C. or less.

In particular, the decomposition of the polycarbonate resin is preferably carried out at a reaction temperature of 60 to 120° C. and normal pressure, more preferably at a reaction temperature of 70 to 110° C. and normal pressure, and at a reaction temperature of 80 to 100° C. and normal pressure. is more preferred.

When the reaction is carried out at the same temperature as in the preparation of the reaction solution, the reaction temperature should be adjusted from the time the polycarbonate resin, alkyl ester, aliphatic alcohol and catalyst are completely mixed to neutralize or distillate to stop the decomposition reaction. It is the average temperature up to the point at which the previous run was started. In addition, when the temperature is raised after the reaction solution is prepared and the reaction is performed, it is the average temperature from the time when the predetermined temperature is reached to the time when the neutralization or distillation operation for stopping the decomposition reaction is started. .

(reaction time)
The reaction time is appropriately selected depending on the slurry concentration, reaction temperature, etc., but if it is long, the bisphenol produced tends to decompose, so it is preferably 30 hours or less, 25 hours or less, 20 hours or less. , 15 hours or less, 10 hours or less, and 5 hours or less, in this order, the shorter the better. If the reaction time is short, the decomposition reaction may not proceed sufficiently. Therefore, the reaction time is preferably 0.1 hour or longer, more preferably 0.5 hour or longer, and still more preferably 1 hour or longer.

The reaction time is the time from the completion of the mixing of the polycarbonate resin, alkyl ester, aliphatic alcohol and catalyst to the start of neutralization and distillation to stop the decomposition reaction. The end point of the reaction time may be determined by tracking the decomposition reaction by liquid chromatography or the like.

(Method for stopping decomposition reaction of polycarbonate resin)
A method for stopping the decomposition reaction of the polycarbonate resin is appropriately selected depending on the type of catalyst used. When an alkylamine or pyridine is used as a catalyst, the decomposition reaction can be stopped by distilling off or neutralizing the alkylamine or pyridine. In the method of removing the alkylamine or pyridine by neutralization by supplying an acid, an ammonium salt or pyridinium salt is generated and its removal is also required. Therefore, the removal of the alkylamine or pyridine is preferably carried out by distillation. is. When an alkali metal hydroxide, alkali metal alkoxide, alkali metal carbonate, or the like is used as the catalyst, the decomposition reaction can be stopped by neutralization or the like.

Among others, the method for producing bisphenol of the present invention is suitable as a method for producing 2,2-bis(4-hydroxyphenyl)propane (hereinafter sometimes referred to as "bisphenol A").

(Bisphenol recovery)
Bisphenol can be recovered from the reaction solution after the decomposition reaction by means of crystallization, column chromatography, or the like after stopping the decomposition reaction of the polycarbonate resin.

Bisphenol is preferably recovered by crystallization, and the method for producing bisphenol of the present invention preferably has a crystallization step of recovering bisphenol by crystallization. Specifically, after the decomposition reaction of the polycarbonate resin, the organic phase obtained by removing the catalyst and solvent from the reaction solution and adding and mixing the organic solvent is washed with water or saline, and if necessary, Neutralize and wash with ammonium chloride water. The washed organic phase is then cooled and crystallized.

Organic solvents that can be used during neutralization or crystallization include aromatic hydrocarbons such as toluene, xylene, ethylbenzene, diethylbenzene, isopropylbenzene, and mesitylene; Aliphatic hydrocarbons, methanol, ethanol, n-propanol, i-propanol, n-butanol, i-butanol, t-butanol, n-pentanol, i-pentanol, n-hexanol, n-heptanol, n-octanol , n-nonanol, n-decanol, n-undecanol, n-dodecanol, ethylene glycol, diethylene glycol, triethylene glycol and other aliphatic alcohols can be used.

Before the crystallization, excess alkyl ester and organic solvent may be distilled off before crystallization.

[Method for producing bisphenol (1)]
The method for producing bisphenol of the present invention can be a method (1) for producing bisphenol having the following steps A, B1 and C1.
Step A: Step of decomposing a polycarbonate resin in the presence of an alkyl ester, an aliphatic alcohol and a catalyst to obtain a bisphenol-containing polycarbonate decomposition solution Step B1: Concentrating the polycarbonate decomposition solution obtained in Step A and concentrating Step of obtaining liquid Step C1: An aromatic hydrocarbon is supplied to the concentrated liquid obtained in Step B1 and crystallized to precipitate bisphenol to obtain a slurry containing bisphenol, and the resulting slurry is subjected to solid-liquid separation. to obtain bisphenol

Each step will be described in detail below.

[Step A]
In step A, for example, a solution containing a polycarbonate resin, an alkyl ester, an aliphatic alcohol, and a catalyst is stirred for a predetermined time. As a result, the polycarbonate resin is decomposed to produce bisphenol, and a bisphenol-containing polycarbonate decomposition solution is obtained. The types of polycarbonate resins, alkyl esters, aliphatic alcohols, catalysts, their mixing ratios, reaction temperatures, etc. are as described above.

[Step B1]
In step B1, concentration of the polycarbonate decomposition solution can be performed by distilling off the solvent. Distillation is preferably carried out so that the concentrated liquid becomes 70% by mass or less of the polycarbonate decomposition liquid, preferably 60% by mass or less, and more preferably 50% by mass or less. . Distillation is preferably carried out so that the concentration of the concentrated liquid is 20% by mass or more, more preferably 30% by mass or more, of the polycarbonate decomposition liquid. Excessive concentration causes the problem that the bisphenol solidifies and the concentrated liquid cannot be extracted. For example, distillation can be carried out at a temperature of 50-200° C. and a pressure of 0.1 kPa to 150 kPa.

Further, the polycarbonate decomposition solution may be concentrated after being neutralized or washed. The neutralization method may be appropriately selected according to the type of catalyst. For example, neutralization when using a basic catalyst is performed by mixing a polycarbonate decomposition solution with an acid such as hydrochloric acid, sulfuric acid, or phosphoric acid. Neutralization is preferably carried out by adjusting the amount of acid to be mixed so that the pH becomes 5.5 to 9.0 (preferably pH 6.0 to 8.0). After mixing the polycarbonate decomposing solution and the acid, the aqueous phase is removed, or if the neutralized salt precipitates, the neutralized salt is removed to obtain a neutralized solution containing bisphenol. This neutralized liquid may be concentrated.

[Step C1]
In step C1, first, the concentrated liquid and the aromatic hydrocarbon are mixed, and bisphenol is precipitated from the mixed liquid containing the concentrated liquid and the aromatic hydrocarbon by crystallization. Examples of the aromatic hydrocarbon to be mixed with the concentrated liquid include toluene, xylene, ethylbenzene, diethylbenzene, isopropylbenzene, mesitylene, etc. Toluene is preferred.

Crystallization can usually be carried out by cooling a liquid mixture containing the concentrate and the aromatic hydrocarbon. For example, the temperature before crystallization is set to 60 to 100°C (preferably 70 to 90°C) and cooled to 40 to 70°C (preferably 40 to 65°C). As a result, bisphenol is precipitated in the mixed liquid, and a slurry containing bisphenol is obtained.

Then, the bisphenol can be recovered as a solid by solid-liquid separation of the slurry containing bisphenol. Solid-liquid separation can be performed by known means such as filtration and centrifugation. For example, solid-liquid separation is performed using a horizontal belt filter, rotary vacuum filter, rotary pressure filter, batch filter, centrifugal filter separator, centrifugal sedimentation separator, a hybrid centrifuge (screen ball decanter), etc. be able to.

The obtained bisphenol may be further purified by washing with water, suspension washing, or the like. Also, crystallization may be performed multiple times. By dissolving the bisphenol obtained in step C1 in an aromatic hydrocarbon and crystallizing the obtained solution, bisphenol with higher purity can be precipitated.

[Method for producing bisphenol (2)]
The method for producing bisphenol of the present invention can be a method (2) for producing bisphenol having the following steps A, B2 and C2.
Step A: Step of decomposing a polycarbonate resin in the presence of an alkyl ester, an aliphatic alcohol and a catalyst to obtain a bisphenol-containing polycarbonate decomposition solution Step B2: The polycarbonate decomposition solution obtained in Step A and an aromatic monoalcohol Step C2: Step of recovering bisphenol from the solution containing bisphenol and aromatic monoalcohol obtained in Step B.

Each step will be described in detail below.

The step A of the bisphenol production method (2) is the same as the step A of the bisphenol production method (1).

[Step B2]
In step B2, the alkyl diester and the aliphatic alcohol can be distilled off by distilling the solution containing the polycarbonate decomposition solution and the aromatic monoalcohol. For example, distillation can be carried out at a temperature of 50-200° C. and a pressure of 0.1 kPa to 150 kPa. It is also preferable to distill off at least part of the aromatic monoalcohol by distillation.

In addition, the polycarbonate decomposition solution may be subjected to the next step after being neutralized and washed in the same manner as in step B1 of the bisphenol production method (1). May be mixed.

[Step C2]
Crystallization or the like can be used to recover bisphenol from the solution containing bisphenol and aromatic monoalcohol obtained in step B2. For example, when a polycarbonate resin derived from bisphenol A is used and phenol is used as the aromatic monoalcohol in step B2, a polycarbonate decomposition solution containing bisphenol A is obtained in step A, and bisphenol A and phenol are used in step B2. A solution containing
In step C2, the solution containing bisphenol A and phenol is crystallized to obtain adduct crystals of bisphenol A and phenol, and then phenol is removed from the melt of the adduct crystals to obtain bisphenol A. . In addition, a solution containing bisphenol A and phenol can be incorporated into the reaction process and purification process of a production plant that produces bisphenol A from acetone and phenol, the mother liquor circulation process (the process of alkaline decomposition of bisphenol A in the mother liquor), etc. , Crystallization is performed together with bisphenol A produced in the production plant to obtain adduct crystals of bisphenol A and phenol, and then phenol is removed from the melt of the adduct crystals to obtain bisphenol A. good.

<Uses of bisphenol>
Bisphenol obtained by the method for producing bisphenol of the present invention (hereinafter sometimes referred to as "recycled bisphenol") can be used in various applications such as optical materials, recording materials, insulating materials, transparent materials, electronic materials, adhesive materials, and heat-resistant materials. Various thermoplastic resins such as polyether resins, polyester resins, polyarylate resins, polycarbonate resins, polyurethane resins, acrylic resins, epoxy resins, unsaturated polyester resins, phenolic resins, polybenzoxazine resins, cyanates It can be used as a constituent component of various thermosetting resins such as resins, a curing agent, an additive, or a precursor thereof. It is also useful as an additive such as a color developer for heat-sensitive recording materials, an anti-fading agent, a bactericide, and an antibacterial and antifungal agent.

Among these, it is preferable to use it as a raw material (monomer) for thermoplastic resins and thermosetting resins, and more preferably as a raw material for polycarbonate resins and epoxy resins, because it can impart good mechanical properties. It is also preferably used as a developer, and more preferably used in combination with a leuco dye and a discoloration temperature regulator.

<Method for Producing Recycled Polycarbonate Resin of the Present Invention>
The present invention provides a method for producing a recycled polycarbonate resin (hereinafter referred to as " It may be described as "method for producing recycled polycarbonate resin of the present invention"). The method for producing recycled polycarbonate resin of the present invention utilizes a chemical recycling method in which polycarbonate resin is produced using recycled bisphenol obtained by decomposing polycarbonate resin contained in waste plastic or the like into bisphenol, which is a monomer, as a raw material.

The method for producing the polycarbonate resin of the present invention can be carried out by appropriately selecting a known polymerization method for a polycarbonate resin, except that a bisphenol raw material containing recycled bisphenol is used as the bisphenol. Polycarbonate resins are generally produced by polymerizing bisphenol and carbonic diester in the presence of a catalyst.

In the method for producing a recycled polycarbonate resin of the present invention, the recycled polycarbonate resin can be obtained, for example, by polymerizing a bisphenol raw material containing recycled bisphenol (the bisphenol obtained by the method for producing a bisphenol of the present invention) and a diester carbonate raw material. can be done.

For example, a recycled polycarbonate resin can be produced by a method such as transesterifying a bisphenol raw material containing recycled bisphenol and a carbonate diester raw material such as diphenyl carbonate in the presence of an alkali metal compound and/or an alkaline earth metal compound. can.

The regenerated bisphenol may be used as a whole bisphenol raw material, or may be used as a part of the bisphenol raw material by mixing with a general bisphenol that is not regenerated bisphenol. The amount of regenerated bisphenol is not particularly limited, and may be 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, or 70% by mass. % or more, 80% by mass or more, or 90% by mass or more. The larger the ratio of recycled bisphenol, the more environmentally friendly it is. Therefore, from the viewpoint of consideration for the environment, the amount of recycled bisphenol relative to the bisphenol raw material is preferably large.

The transesterification reaction can be carried out by appropriately selecting a known method, and an example of a method using diphenyl carbonate as a starting material for the diester carbonate will be described below.

In the method for producing a recycled polycarbonate resin of the present invention, it is preferable to use an excessive amount of diphenyl carbonate relative to the bisphenol raw material. The amount of diphenyl carbonate used with respect to the bisphenol raw material is preferably large in terms of the produced regenerated polycarbonate resin having few terminal hydroxyl groups and excellent thermal stability of the polymer. From the viewpoint of easy production of a recycled polycarbonate resin having a molecular weight, it is preferably small. For these reasons, the amount of diphenyl carbonate used per 1 mol of the bisphenol raw material is usually 1.001 mol or more, preferably 1.002 mol or more, and usually 1.3 mol or less, preferably 1.2 mol. It is below.

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

A transesterification catalyst is usually used when producing a recycled polycarbonate resin by transesterification reaction between diphenyl carbonate and a bisphenol raw material. An alkali metal compound and/or an alkaline earth metal compound is preferably used as this transesterification catalyst. These may be used alone, or two or more of them may be used in any combination and ratio. Practically, it is desirable to use an alkali metal compound.

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

When the amount of the catalyst used is within the above range, the polymerization activity necessary for producing a recycled polycarbonate resin having a desired molecular weight can be easily obtained, the polymer color is excellent, and excessive branching of the polymer does not proceed. It is easy to obtain a polycarbonate resin with excellent fluidity during molding.
In order to produce a recycled polycarbonate resin by the above method, it is preferable to continuously supply both the above raw materials to a raw material mixing tank, and continuously supply the obtained mixture and the transesterification catalyst to a polymerization tank.

In the production of recycled polycarbonate resin by the transesterification method, both raw materials supplied to a raw material mixing tank are generally stirred uniformly and then fed to a polymerization tank in which a catalyst is added to produce a polymer.

(Recycled polycarbonate resin and its composition)
The recycled polycarbonate resin obtained by the method for producing a recycled polycarbonate resin of the present invention may be used as it is, or may be used as a recycled polycarbonate resin composition containing unused polycarbonate resin and recycled polycarbonate resin. The recycled polycarbonate resin composition can be obtained by appropriately selecting a known kneading method or the like to mix virgin polycarbonate resin and recycled polycarbonate resin. When a recycled polycarbonate resin composition containing unused polycarbonate resin and recycled polycarbonate resin is used, the amount of recycled polycarbonate resin is not particularly limited, but the larger the proportion of recycled polycarbonate resin, the more environmentally friendly. Therefore, from the viewpoint of consideration for the environment, the amount of the recycled polycarbonate resin relative to the recycled polycarbonate resin composition is preferably 50% by mass or more, and the larger the amount, the higher is 70% by mass or more, 80% by mass or more, and 90% by mass or more. more preferred.

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

<Method for producing epoxy resin>
The present invention relates to a method for producing an epoxy resin, comprising obtaining bisphenol through the method for producing bisphenol of the present invention and then producing an epoxy resin using a polyhydric hydroxy compound starting material containing the bisphenol. The present invention also relates to a method for producing an epoxy resin, comprising further reacting an epoxy resin raw material containing the epoxy resin obtained through the above epoxy resin production method with a polyhydric hydroxy compound raw material to produce an epoxy resin.

In the method for producing an epoxy resin of the present invention, as at least a part of raw materials, recycled bisphenol and/or an epoxy resin produced using recycled bisphenol is used to produce an epoxy resin (hereinafter referred to as "recycled epoxy resin" There is.) to manufacture.

The method for producing the epoxy resin of the present invention is not particularly limited except that the recycled bisphenol (the bisphenol obtained by the method for producing the bisphenol of the present invention) and/or the epoxy resin produced using the recycled bisphenol is used as a raw material. , a known manufacturing method can be used. For example, as described later, regenerated bisphenol can be used as at least a part of the polyhydric hydroxy compound raw material for production using a one-step method, an oxidation method, or a two-step method. The obtained epoxy resin can also be used as at least a part of the epoxy resin raw material for production using the two-step method.

In addition, the "epoxy resin raw material" means an epoxy resin used as a raw material in the method for producing an epoxy resin of the present invention. "Polyvalent hydroxy compound" is a general term for dihydric or higher phenol compounds and dihydric or higher alcohol compounds, and "polyhydric hydroxy compound raw material" is used as a raw material for the method for producing an epoxy resin of the present invention. hydroxy compounds.

As a method for producing the epoxy resin of the present invention, a one-step method, an oxidation method, a two-step method, or the like can be used.
The one-step method for producing an epoxy resin is a method of obtaining an epoxy resin by reacting regenerated bisphenol (the bisphenol obtained by the method for producing bisphenol of the present invention) with epihalohydrin.
The method for producing an epoxy resin by an oxidation method is a method in which a regenerated bisphenol is allylated with an allyl halide (such as allyl chloride or allyl bromide) and then subjected to an oxidation reaction to obtain an epoxy resin.
The two-step method for producing an epoxy resin is a method in which an epoxy resin raw material and a polyhydric hydroxy compound raw material are reacted, and recycled bisphenol and/or an epoxy resin produced using recycled bisphenol is used as the raw material.

Methods for producing an epoxy resin using a one-step method, an oxidation method, and a two-step method are described below.

(Method for producing epoxy resin by one-step method)
In the present invention, the method for producing the epoxy resin by the one-step method is not particularly limited as long as it is a known production method, and will be described in detail below.

In the one-step method for producing an epoxy resin, the recycled bisphenol may be produced by using a polyhydroxy compound other than the recycled bisphenol (hereinafter sometimes referred to as "another polyhydroxy compound"). That is, the method for producing an epoxy resin by the one-step method is a method of obtaining an epoxy resin by reacting a polyhydric hydroxy compound raw material with epihalohydrin, and at least a part of the polyhydric hydroxy compound raw material is a method of regenerated bisphenol. can be done.

The content of regenerated bisphenol in the polyhydric hydroxy compound raw material is not particularly limited, but is preferably 1 to 100% by mass, more preferably 10 to 100% by mass, because a high content of regenerated bisphenol is environmentally friendly.

Here, "another polyhydric hydroxy compound" is a general term for phenol compounds having a valence of 2 or more and alcohol compounds having a valence of 2 or more, excluding regenerated bisphenol. In the one-step method for producing an epoxy resin, the "polyhydroxy compound raw material" is the total polyhydroxy compound including the regenerated bisphenol and optionally other polyhydroxy compounds.

Other polyhydric hydroxy compounds include bisphenol A, tetramethylbisphenol A, bisphenol F, tetramethylbisphenol F, bisphenol S, bisphenol C, bisphenol AD, bisphenol AF, hydroquinone, resorcin, methylresorcin, biphenol, tetramethylbiphenol, Dihydroxynaphthalene, dihydroxydiphenyl ether, thiodiphenols, phenol novolak resin, cresol novolak resin, phenol aralkyl resin, biphenyl aralkyl resin, naphthol aralkyl resin, terpene phenol resin, dicyclopentadiene phenol resin, bisphenol A novolak resin, naphthol novolak resin, Various polyhydric phenols such as brominated bisphenol A and brominated phenol novolak resins, and polyhydric phenols obtained by condensation reaction of various phenols with various aldehydes such as benzaldehyde, hydroxybenzaldehyde, crotonaldehyde, glyoxal, etc. Resins, polyhydric phenol resins obtained by the condensation reaction of xylene resin and phenols, various phenolic resins such as co-condensation resins of heavy oils or pitches, phenols and formaldehydes, ethylene glycol, Chains such as methylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, 1,3-pentanediol, 1,4-pentanediol, 1,5-pentanediol, 1,6-hexanediol cycloaliphatic diols, cyclic aliphatic diols such as cyclohexanediol and cyclodecanediol, and polyalkylene ether glycols such as polyethylene ether glycol, polyoxytrimethylene ether glycol and polypropylene ether glycol.

In the reaction, the polyhydric hydroxy compound raw material is dissolved in epihalohydrin to form a uniform solution. As the epihalohydrin, epichlorohydrin or epibromohydrin is usually used, and epichlorohydrin is preferred in the present invention.

The amount of epihalohydrin to be used is usually 1.0 to 14.0 equivalents, particularly 2.0 to 10.0 equivalents, per equivalent of hydroxyl groups in the starting polyhydroxy compound (all polyhydroxy compounds). is preferred. When the amount of epihalohydrin is at least the above lower limit, it is preferable because the polymerization reaction can be easily controlled and the resulting epoxy resin can have an appropriate epoxy equivalent weight. On the other hand, when the amount of epihalohydrin is equal to or less than the above upper limit, production efficiency tends to improve, which is preferable.

Then, while stirring the solution, an alkali metal hydroxide is added in an amount corresponding to usually 0.1 to 3.0 equivalents, preferably 0.8 to 2.0 equivalents, per 1 equivalent of the hydroxyl group of the polyvalent hydroxy compound raw material. It is added as a solid or an aqueous solution to react. When the amount of the alkali metal hydroxide added is at least the above lower limit, the reaction between the unreacted hydroxyl groups and the produced epoxy resin is less likely to occur, and the polymerization reaction can be easily controlled, which is preferable. Moreover, it is preferable that the amount of the alkali metal hydroxide to be added is equal to or less than the above upper limit because impurities due to side reactions are less likely to be generated. Alkali metal hydroxides used herein typically include sodium hydroxide or potassium hydroxide.

This reaction can be carried out under normal pressure or under reduced pressure, and the reaction temperature is preferably 20 to 200°C, more preferably 40 to 150°C. When the reaction temperature is equal to or higher than the above lower limit, it is preferable because it facilitates the progress of the reaction and facilitates control of the reaction. In addition, if the reaction temperature is equal to or lower than the above upper limit, the side reaction is less likely to proceed, and particularly the amount of polymer can be easily reduced, which is preferable.

In addition, in this reaction, the reaction liquid is azeotroped while maintaining a predetermined temperature as necessary, and the condensed liquid obtained by cooling the volatilizing steam is separated into oil and water, and the oil content after removing the water is reacted. It is carried out while dehydrating by the method of returning to the system. The alkali metal hydroxide is added intermittently or continuously little by little over a period of preferably 0.1 to 24 hours, more preferably 0.5 to 10 hours, in order to suppress abrupt reaction. When the addition time of the alkali metal hydroxide is longer than the above lower limit, it is possible to prevent the reaction from progressing rapidly, and the reaction temperature can be easily controlled, which is preferable. If the addition time is equal to or less than the above upper limit, the amount of polymer can be easily reduced, which is preferable.

After completion of the reaction, the insoluble by-product salt can be filtered off or removed by washing with water, and then unreacted epihalohydrin can be removed by heating and/or distillation under reduced pressure.

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

Furthermore, in this reaction, alcohols such as ethanol and isopropanol; ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone; ethers such as dioxane and ethylene glycol dimethyl ether; glycol ethers such as methoxypropanol; You may use an inert organic solvent, such as an aprotic polar solvent, such as.

[Production of epoxy resin with reduced total chlorine content]
If it is necessary to reduce the total chlorine content of the epoxy resin obtained as described above, the epoxy resin can be produced with a reduced total chlorine content by reaction with alkali.

An organic solvent for dissolving the epoxy resin may be used for the reaction with the alkali. Although the organic solvent used in the reaction is not particularly limited, it is preferable to use a ketone-based organic solvent from the viewpoint of production efficiency, handleability, workability, and the like. In addition, an aprotic polar solvent may be used from the viewpoint of lowering the amount of hydrolyzable chlorine.

Examples of ketone-based organic solvents include ketone-based solvents such as methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone. Methyl isobutyl ketone is particularly preferred because of its effects and ease of post-treatment. These may be used individually by 1 type, and may be used in mixture of 2 or more types.

Aprotic polar solvents include, for example, dimethylsulfoxide, diethylsulfoxide, dimethylsulfone, sulfolane, dimethylformamide, dimethylacetamide, hexamethylphosphoramide and the like. These may be used individually by 1 type, and may be used in mixture of 2 or more types. Among these aprotic polar solvents, dimethylsulfoxide is preferred because it is readily available and has excellent effects.

The amount of the solvent used is such that the concentration of the epoxy resin in the liquid to be treated with alkali is usually 1 to 95% by mass, preferably 5 to 80% by mass.

As alkali, solid or solution of alkali metal hydroxide can be used. Examples of alkali metal hydroxides include potassium hydroxide and sodium hydroxide, preferably sodium hydroxide. Also, the alkali metal hydroxide may be dissolved in an organic solvent or water. Preferably, the alkali metal hydroxide is used as a solution dissolved in an aqueous solvent or an organic solvent.

The amount of the alkali metal hydroxide to be used is preferably 0.01 to 20.0 parts by mass or less per 100 parts by mass of the epoxy resin in terms of the solid content of the alkali metal hydroxide. More preferably, it is 0.10 to 10.0 parts by mass. If the amount of alkali metal hydroxide used is less than the above lower limit, the effect of reducing the total chlorine content is low.

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

After the reaction, excess alkali metal hydroxides and secondary salts can be removed by a method such as washing with water, and the organic solvent can be removed by heating and/or vacuum distillation and/or steam distillation.

(Method for producing epoxy resin by oxidation method)
The method for producing an epoxy resin by an oxidation method is not particularly limited as long as it is a known production method. It can be carried out according to the methods described.

In the method for producing an epoxy resin by the oxidation method, similarly to the one-step method, a polyhydric hydroxy compound other than the regenerated bisphenol may be used in combination with the regenerated bisphenol. That is, the method for producing an epoxy resin by an oxidation method is a method for obtaining an epoxy resin by allylating a polyhydroxy compound raw material with an allyl halide and then subjecting it to an oxidation reaction. Part can be a method in which the recycled bisphenol.

In the method of producing an epoxy resin by an oxidation method, the "polyhydroxy compound raw material" is a total polyhydroxy compound that is a combination of recycled bisphenol and other polyhydroxy compounds that are used as necessary. Examples of the hydroxy compound include those used in the one-step method. The content of regenerated bisphenol in the polyhydric hydroxy compound raw material is not particularly limited, but is preferably 1 to 100% by mass, more preferably 10 to 100% by mass, because a high content of regenerated bisphenol is environmentally friendly.

(Method for producing epoxy resin by two-step method)
The method for producing an epoxy resin by the two-step method is not particularly limited as long as it is a known production method, and will be described in detail below.

The method for producing an epoxy resin by a two-step method has a step of reacting an epoxy resin raw material and a polyhydric hydroxy compound raw material, and at least part of the epoxy resin raw material is an epoxy resin produced using recycled bisphenol. and/or wherein at least a portion of the polyhydric hydroxy compound feedstock is regenerated bisphenol. The two-step method for producing an epoxy resin is any of the following methods (i) to (iii).

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

In method (i), the epoxy resin raw material is an epoxy resin other than the epoxy resin produced using recycled bisphenol. Further, the polyhydric hydroxy compound raw material is a total polyhydric hydroxy compound obtained by combining regenerated bisphenol and other polyhydric hydroxy compounds used as necessary.

Method (ii): A method of reacting an epoxy resin raw material containing an epoxy resin produced using recycled bisphenol with a polyhydric hydroxy compound raw material containing recycled bisphenol.

In method (ii), the epoxy resin raw material is a total epoxy resin, which is a combination of an epoxy resin produced using recycled bisphenol and other epoxy resins used as necessary. Further, the polyhydric hydroxy compound raw material is a total polyhydric hydroxy compound obtained by combining regenerated bisphenol and other polyhydric hydroxy compounds used as necessary.

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

In method (iii), the epoxy resin raw material is a total epoxy resin, which is a combination of an epoxy resin produced using recycled bisphenol and other epoxy resins used as necessary. Moreover, the polyhydric hydroxy compound raw material is a polyhydric hydroxy compound other than the regenerated bisphenol.

The epoxy resin produced using the regenerated bisphenol used in methods (ii) and (iii) can be obtained by a one-step method for producing an epoxy resin or a method for producing an epoxy resin by an oxidation method. Moreover, you may use the epoxy resin obtained by the method (i). The epoxy resin other than the epoxy resin produced using the recycled bisphenol is the same as the other epoxy resin described later in the method for producing a cured epoxy resin, and the other polyvalent hydroxy compound is the same as the one-step method. It is the same.

In method (i) and method (ii), the content of the regenerated bisphenol in the polyhydric hydroxy compound containing regenerated bisphenol is not particularly limited. Preferably, 10 to 100% by mass is more preferable.
In methods (ii) and (iii), the content of the epoxy resin produced using the recycled bisphenol in the epoxy resin raw material containing the epoxy resin produced using the recycled bisphenol is not particularly limited. Since a high content of the epoxy resin produced using is environmentally friendly, it is preferably 1 to 100% by mass, more preferably 10 to 100% by mass.

In the two-step reaction, the amounts of the epoxy resin raw material and the polyhydric hydroxy compound raw material used are such that the blending equivalent ratio is (epoxy group equivalent):(hydroxyl group equivalent)=1:0.1 to 2.0. It is preferable to More preferably, it is 1:0.2 to 1.2. When the equivalent ratio is within the above range, the molecular weight can be easily increased, and more terminal epoxy groups can be left, which is preferable.

In addition, a catalyst may be used in the reaction by the two-step method, and as the catalyst, any compound having a catalytic ability to promote the reaction between an epoxy group and a phenolic hydroxyl group or an alcoholic hydroxyl group may be used. It's okay. Examples thereof include alkali metal compounds, organic phosphorus compounds, tertiary amines, quaternary ammonium salts, cyclic amines, imidazoles and the like. Among these, quaternary ammonium salts are preferred. In addition, one type of catalyst can be used alone, or two or more types can be used in combination. The amount of catalyst used is usually 0.001 to 10% by mass based on the epoxy resin raw material.

In addition, in the two-step reaction, a solvent may be used, and any solvent that dissolves the epoxy resin starting material may be used. Examples thereof include aromatic solvents, ketone solvents, amide solvents, glycol ether solvents and the like. Only one type of solvent may be used, or two or more types may be used in combination. Also, the resin concentration in the solvent is preferably 10 to 95% by mass. More preferably, it is 20 to 80% by mass. Further, when a highly viscous product is generated during the reaction, the solvent can be additionally added to continue the reaction. After completion of the reaction, the solvent can be removed or added as necessary.

In the two-step reaction, the reaction temperature is preferably 20-250°C, more preferably 50-200°C. If the reaction temperature is higher than the above upper limit, the resulting epoxy resin may deteriorate. Further, if the content is below the above lower limit, the reaction may not proceed sufficiently. Further, the reaction time is usually 0.1 to 24 hours, preferably 0.5 to 12 hours.

<Method for Producing Cured Epoxy Resin>
In the method for producing a cured epoxy resin product of the present invention, an epoxy resin is obtained through the above-described method for producing an epoxy resin, and a composition containing the epoxy resin and a curing agent (hereinafter sometimes referred to as an "epoxy resin composition") ), the epoxy resin composition is cured to obtain a cured epoxy resin.

If necessary, the epoxy resin composition may contain epoxy resins other than the epoxy resin obtained by the method for producing an epoxy resin of the present invention (hereinafter sometimes simply referred to as "other epoxy resins"), Curing agents, curing accelerators, inorganic fillers, coupling agents, and the like can be appropriately blended.

The content of the recycled epoxy resin in the epoxy resin composition is not particularly limited. Since a high recycled epoxy resin content is environmentally friendly, the recycled epoxy resin is preferably 40 parts by mass or more, more preferably 60 parts by mass or more, with respect to 100 parts by mass of all epoxy resin components in the epoxy resin composition. When other epoxy resins are included, the recycled epoxy resin can be 40 to 99 parts by mass, or 60 to 99 parts by mass, etc., with respect to 100 parts by mass of all epoxy resin components in the epoxy resin composition. The "total epoxy resin component" corresponds to the amount of all epoxy resins contained in the epoxy resin composition, and is the sum of the recycled epoxy resin and other epoxy resins used as necessary.

(curing agent)
In the present invention, the curing agent refers to a substance that contributes to cross-linking reaction and/or chain extension reaction between epoxy groups of epoxy resin. In the present invention, even if a substance is usually called a "curing accelerator", it can be regarded as a curing agent as long as it contributes to the cross-linking reaction and/or chain extension reaction between the epoxy groups of the epoxy resin. and

In the epoxy resin composition, the content of the curing agent is preferably 0.1 to 1000 parts by mass with respect to 100 parts by mass of the total epoxy resin component. Moreover, it is more preferably 500 parts by mass or less.

There are no particular restrictions on the curing agent, and any one generally known as an epoxy resin curing agent can be used. For example, phenolic curing agents, aliphatic amines, polyether amines, alicyclic amines, amine curing agents such as aromatic amines, acid anhydride curing agents, amide curing agents, tertiary amines, imidazoles, etc. are mentioned. One curing agent may be used alone, or two or more curing agents may be used in combination. When two or more curing agents are used in combination, they may be mixed in advance to prepare a mixed curing agent before use, or the recycled epoxy resin obtained by the method for producing an epoxy resin of the present invention and other epoxy resins. Each component of the curing agent may be added separately and mixed at the same time.

[Phenolic curing agent]
Specific examples of phenol-based curing agents include recycled 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, phenol novolak resin, cresol novolak resin, phenol aralkyl resin, biphenyl aralkyl resin, naphthol aralkyl resin, terpene phenol resin, dicyclopentadiene phenol resin, bisphenol A novolak resin, Various polyhydric phenols such as trisphenolmethane type resins, naphthol novolac resins, brominated bisphenol A, brominated phenol novolac resins, various phenols and various aldehydes such as benzaldehyde, hydroxybenzaldehyde, crotonaldehyde, and glyoxal polyhydric phenol resins obtained by the condensation reaction with, polyhydric phenol resins obtained by the condensation reaction of xylene resin and phenols, co-condensation resins of heavy oils or pitches, phenols and formaldehydes, phenol Benzaldehyde/xylylene dimethoxide polycondensate, phenol/benzaldehyde/xylylene dihalide polycondensate, phenol/benzaldehyde/4,4'-dimethoxide biphenyl polycondensate, phenol/benzaldehyde/4,4'-dihalide Various phenolic resins such as biphenyl polycondensates can be used.

These phenol-based curing agents may be used alone or in combination of two or more in an arbitrary combination and mixing ratio.

The amount of the phenol-based curing agent is preferably 0.1 to 1000 parts by mass, and more preferably 500 parts by mass or less, based on 100 parts by mass of all epoxy resin components in the epoxy resin composition.

[Amine curing agent]
Examples of amine curing agents (excluding tertiary amines) include aliphatic amines, polyetheramines, alicyclic amines, aromatic amines and the like.

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

Examples of polyetheramines include triethylene glycol diamine, tetraethylene glycol diamine, diethylene glycol bis(propylamine), polyoxypropylene diamine, and polyoxypropylene triamines.

Examples of alicyclic amines include isophoronediamine, methacenediamine, N-aminoethylpiperazine, bis(4-amino-3-methyldicyclohexyl)methane, bis(aminomethyl)cyclohexane, 3,9-bis(3-amino Propyl)-2,4,8,10-tetraoxaspiro(5,5)undecane, norbornenediamine and the like are exemplified.

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

The above-mentioned amine-based curing agents may be used alone, or two or more of them may be used in combination in any desired combination and mixing ratio.

The above amine-based curing agent can be used so that the equivalent ratio of the functional groups in the curing agent to the epoxy groups in all the epoxy resin components contained in the epoxy resin composition is in the range of 0.1 to 2.0. preferable. More preferably, the equivalent ratio is in the range of 0.8 to 1.2. Within this range, unreacted epoxy groups and functional groups of the curing agent are less likely to remain, which is preferable.

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

The above tertiary amine can be used so that the equivalent ratio of the functional group in the curing agent to the epoxy group in all the epoxy resin components contained in the epoxy resin composition is in the range of 0.1 to 2.0. preferable. More preferably, the equivalent ratio is in the range of 0.8 to 1.2. Within this range, unreacted epoxy groups and functional groups of the curing agent are less likely to remain, which is preferable.

[Acid anhydride curing agent]
Acid anhydride-based curing agents include acid anhydrides, modified acid anhydrides, and the like.

Examples of acid anhydrides include phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, benzophenonetetracarboxylic anhydride, dodecenylsuccinic anhydride, polyadipic anhydride, polyazelaic anhydride, and polysebacic acid. Anhydride, poly(ethyloctadecanedioic anhydride), poly(phenylhexadecanedioic anhydride), tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, hexahydrophthalic anhydride , methylhimic acid anhydride, trialkyltetrahydrophthalic anhydride, methylcyclohexene dicarboxylic acid anhydride, methylcyclohexene tetracarboxylic acid anhydride, ethylene glycol bistrimellitate dianhydride, het acid anhydride, nadic acid anhydride, methyl nadic anhydride, 5-(2,5-dioxotetrahydro-3-furanyl)-3-methyl-3-cyclohexane-1,2-dicarboxylic anhydride, 3,4-dicarboxy-1,2, 3,4-tetrahydro-1-naphthalenesuccinic dianhydride, 1-methyl-dicarboxy-1,2,3,4-tetrahydro-1-naphthalenesuccinic dianhydride and the like.

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

The above-mentioned acid anhydride-based curing agents may be used alone or in combination of two or more in any desired combination and blending amount.

When using an acid anhydride-based curing agent, it should be used so that the equivalent ratio of the functional group in the curing agent to the epoxy groups in all the epoxy resin components in the epoxy resin composition is in the range of 0.1 to 2.0. is preferred. More preferably, the equivalent ratio is in the range of 0.8 to 1.2. Within this range, unreacted epoxy groups and functional groups of the curing agent are less likely to remain, which is preferable.

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

[Imidazoles]
Examples of imidazoles include 2-phenylimidazole, 2-ethyl-4(5)-methylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-phenylimidazole, 1 -Cyanoethyl-2-undecylimidazole, 1-cyano-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazole trimellitate, 1-cyanoethyl-2-phenylimidazolium trimellitate, 2,4-diamino- 6-[2′-methylimidazolyl-(1′)]-ethyl-s-triazine, 2,4-diamino-6-[2′-ethyl-4′-methylimidazolyl-(1′)]-ethyl-s -triazine, 2,4-diamino-6-[2′-methylimidazolyl-(1′)]-ethyl-s-triazine isocyanurate, 2-phenylimidazole isocyanurate, 2-phenyl-4,5 -dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, adducts of epoxy resins and the above imidazoles, and the like. Since imidazoles have catalytic activity, they can be generally classified as curing accelerators, but in the present invention they are classified as curing agents.
The above-mentioned imidazoles may be used singly or as a mixture of two or more in any combination and ratio.

When imidazoles are used, it is preferable to use imidazoles in an amount of 0.1 to 20% by mass based on the sum of all epoxy resin components and imidazoles in the epoxy resin composition.

[Other curing agents]
Other curing agents can be used in the epoxy resin composition in addition to the curing agents described above. Other curing agents that can be used in the epoxy resin composition are not particularly limited, and all those generally known as curing agents for epoxy resins can be used.
These other curing agents may be used alone or in combination of two or more.

[Other epoxy resins]
The epoxy resin composition can contain epoxy resins other than the epoxy resin obtained by the method for producing an epoxy resin of the present invention. Various physical properties can be improved by including other epoxy resins.

Other epoxy resins that can be used in the epoxy resin composition include all epoxy resins other than the epoxy resin obtained by the method for producing an epoxy resin of the present invention. Specific examples include bisphenol A-type epoxy resin, bisphenol C-type epoxy resin, trisphenolmethane-type epoxy resin, anthracene-type epoxy resin, phenol-modified xylene resin-type epoxy resin, bisphenolcyclododecyl-type epoxy resin, and bisphenoldiisopropylideneresorcin type. Epoxy resin, bisphenol F type epoxy resin, bisphenol AD type epoxy resin, bisphenol AF type epoxy resin, hydroquinone type epoxy resin, methylhydroquinone type epoxy resin, dibutylhydroquinone type epoxy resin, resorcin type epoxy resin, methylresorcin type epoxy resin, biphenol type epoxy resin, tetramethylbiphenol type epoxy resin, tetramethylbisphenol F type epoxy resin, dihydroxydiphenyl ether type epoxy resin, epoxy resin derived from thiodiphenols, dihydroxynaphthalene type epoxy resin, dihydroxyanthracene type epoxy resin, dihydroxydihydro Anthracene type epoxy resin, dicyclopentadiene type epoxy resin, epoxy resin derived from dihydroxystilbenes, phenol novolac type epoxy resin, cresol novolak type epoxy resin, bisphenol A novolac type epoxy resin, naphthol novolac type epoxy resin, 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, phenol/crotonaldehyde condensates Epoxy resins derived from, epoxy resins derived from phenol-glyoxal condensates, epoxy resins derived from co-condensation resins of heavy oils or pitches, phenols and formaldehydes, derived from diaminodiphenylmethane Examples include epoxy resins, epoxy resins derived from aminophenol, epoxy resins derived from xylenediamine, epoxy resins derived from methylhexahydrophthalic acid, and epoxy resins derived from dimer acid. These may be used alone, or two or more may be used in any combination and blending ratio.

When the epoxy resin composition contains the above other epoxy resin, the content thereof is preferably 1 to 60 parts by mass, more preferably 40 parts by mass, based on 100 parts by mass of all epoxy resin components in the composition. It is below the department.

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

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

Phosphorus compounds that can be used as curing accelerators include triphenylphosphine, diphenyl(p-tolyl)phosphine, tris(alkylphenyl)phosphine, tris(alkoxyphenyl)phosphine, tris(alkyl/alkoxyphenyl)phosphine, tris( dialkylphenyl)phosphine, tris(trialkylphenyl)phosphine, tris(tetraalkylphenyl)phosphine, tris(dialkoxyphenyl)phosphine, tris(trialkoxyphenyl)phosphine, tris(tetraalkoxyphenyl)phosphine, trialkylphosphine, dialkyl Organic phosphines such as arylphosphines and alkyldiarylphosphines, complexes of these organic phosphines with organic borons, and these organic phosphines with maleic anhydride, 1,4-benzoquinone, 2,5-toluquinone, and 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 Examples include quinone compounds such as and compounds obtained by adding compounds such as diazophenylmethane.

Among the curing accelerators listed above, organic phosphines and phosphonium salts are preferred, and organic phosphines are most preferred. In addition, among the curing accelerators listed above, only one type may be used, or two or more types may be mixed and used in an arbitrary combination and ratio.

The curing accelerator is preferably used in an amount of 0.1 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of all epoxy resin components in the epoxy resin composition. When the content of the curing accelerator is at least the above lower limit, a good curing acceleration effect can be obtained.

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

(Release agent)
A release agent can be blended in the epoxy resin composition. Examples of release agents include natural waxes such as carnauba wax, synthetic waxes such as polyethylene wax, higher fatty acids such as stearic acid and zinc stearate and their metal salts, and hydrocarbon release agents such as paraffin. can be done. These may be used alone, or two or more of them may be used in any combination and blending ratio.

The amount of the release agent is preferably 0.001 to 10.0 parts by mass with respect to 100 parts by mass of all the epoxy resin components in the epoxy resin composition. It is preferable that the content of the release agent is within the above range, because good release properties can be exhibited while maintaining curing properties.

(coupling agent)
A coupling agent can be added to the epoxy resin composition. The coupling agent is preferably used in combination with the inorganic filler, and the addition of the coupling agent can improve the adhesion between the matrix epoxy resin and the inorganic filler. Examples of coupling agents include silane coupling agents and titanate coupling agents.

Examples of silane coupling agents include epoxysilanes such as γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ- Aminopropyltriethoxysilane, N-β (aminoethyl) γ-aminopropyltrimethoxysilane, N-β (aminoethyl) γ-aminopropylmethyldimethoxysilane, γ-aminopropyltrimethoxysilane, γ-ureidopropyltriethoxy aminosilanes such as silane, mercaptosilanes such as 3-mercaptopropyltrimethoxysilane, p-styryltrimethoxysilane, vinyltrichlorosilane, vinyltris(β-methoxyethoxy)silane, vinyltrimethoxysilane, vinyltriethoxysilane, γ-methacrylic Examples include vinylsilanes such as roxypropyltrimethoxysilane, epoxy-based, amino-based, and vinyl-based high-molecular-type silanes.

Examples of titanate coupling agents include isopropyl triisostearoyl titanate, isopropyl tri(N-aminoethyl/aminoethyl) titanate, diisopropyl bis(dioctylphosphate) titanate, tetraisopropyl bis(dioctylphosphite) titanate, tetraoctyl bis ( ditridecylphosphite) titanate, tetra(2,2-diallyloxymethyl-1-butyl)bis(ditridecyl)phosphite titanate, bis(dioctylpyrophosphate)oxyacetate titanate, bis(dioctylpyrophosphate)ethylene titanate and the like. be done.

Any one of these coupling agents may be used alone, or two or more thereof may be used in any combination and ratio.

When a coupling agent is used in the epoxy resin composition, the amount thereof is preferably 0.001 to 10.0 parts by weight per 100 parts by weight of the total epoxy resin component. If the amount of the coupling agent is at least the above lower limit, the effect of improving the adhesion between the matrix epoxy resin and the inorganic filler tends to be enhanced by adding the coupling agent. On the other hand, if the amount of the coupling agent is less than the above upper limit, the coupling agent is less likely to bleed out from the resulting cured product, which is preferable.

(Other ingredients)
Components other than those described above can be added to the epoxy resin composition. Other compounding components include, for example, flame retardants, plasticizers, reactive diluents, pigments, etc., and can be appropriately compounded as necessary. However, this does not preclude the use of ingredients other than those listed above.

Flame retardants include halogen-based flame retardants such as brominated epoxy resins and brominated phenol resins, antimony compounds such as antimony trioxide, phosphorus-based flame retardants such as red phosphorus, phosphate esters and phosphines, and melamine derivatives. Nitrogen flame retardants and inorganic flame retardants such as aluminum hydroxide and magnesium hydroxide can be used.

(Curing method)
A cured epoxy resin can be obtained by curing the epoxy resin composition. The curing method is not particularly limited, but usually a cured product can be obtained by a thermosetting reaction by heating. During the thermosetting reaction, it is preferable to appropriately select the curing temperature depending on the type of curing agent used. For example, when a phenolic curing agent is used, the curing temperature is usually 80-250°C. By adding a curing accelerator to these curing agents, it is also possible to lower the curing temperature. The reaction time is preferably 0.01 to 20 hours. When the reaction time is at least the above lower limit, the curing reaction tends to proceed sufficiently, which is preferable. On the other hand, when the reaction time is equal to or less than the above upper limit, deterioration due to heating and energy loss during heating are easily reduced, which is preferable.

(Application)
The epoxy resin cured product obtained by curing the epoxy resin composition has a high elastic modulus at 250° C., and a cured product excellent in heat deformation resistance can be obtained.
Therefore, the epoxy resin cured product can be effectively used in any application as long as these physical properties are required. For example, in the field of coatings such as electrodeposition coatings for automobiles, heavy-duty anti-corrosion coatings for ships and bridges, and coatings for the inner surface of beverage cans; electrical and electronic fields such as laminates, semiconductor sealing materials, insulating powder coatings, and coil impregnation. Suitable for any application such as seismic reinforcement of bridges, reinforcement of concrete, flooring of buildings, lining of water supply facilities, drainage and permeable pavement, and civil engineering, construction, and adhesives for vehicles and aircraft. can be done.

The epoxy resin composition may be used after curing for the above applications or may be cured during the manufacturing process for the above applications.

EXAMPLES The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited by the following examples as long as the gist thereof is not exceeded.

[Raw materials and reagents]
Polycarbonate resin "NOVAREX (registered trademark) M7027BF" manufactured by Mitsubishi Chemical Engineering-Plastics Corporation was used as the polycarbonate resin.
Methanol, phenol, dimethyl malonate, ethylene diacetate, butyl acetate, sodium hydroxide, sodium phenoxide, acetonitrile, and cesium carbonate were reagents supplied by Fujifilm Wako Pure Chemical Industries, Ltd.
Diphenyl carbonate used was a product of Mitsubishi Chemical Corporation.

[analysis]
Production confirmation, purity and quantification of bisphenol A were performed by high performance liquid chromatography under the following procedures and conditions.
・ Quantitative method: internal standard method using biphenyl as an internal standard ・ Apparatus: LC-2010A manufactured by Shimadzu Corporation, Waters 5 μm 150 mm × 4.6 mm ID
・Method: Low-pressure gradient method ・Analysis temperature: 40°C
・Eluent composition:
A solution Acetonitrile B solution 85% phosphoric acid: water = 1 mL: 999 mL solution At analysis time 0 minutes, A solution: B solution = 35: 65 (volume ratio, hereinafter the same), analysis time 0 to 5 minutes is eluent The composition was set to A solution: B solution = 35:65, and then gradually changed to A solution: B solution = 90:10 over an analysis time of 5 to 40 minutes.
・Flow rate: 0.85 mL/min ・Detection wavelength: 280 nm

[Viscosity average molecular weight (Mv)]
Viscosity average molecular weight (Mv) is obtained by dissolving polycarbonate resin in methylene chloride (concentration 6.0 g / L), measuring specific viscosity (ηsp) at 20 ° C. using Ubbelohde viscosity tube, viscosity average molecular weight according to the following formula (Mv) was calculated.
ηsp/C=[η](1+0.28ηsp)
[η]=1.23×10 ⁻⁴ Mv ^0.83

[Pellet YI]
The pellet YI (transparency of polycarbonate resin) was evaluated by measuring the YI value (yellowness index value) of polycarbonate resin pellets in reflected light according to ASTM D1925. A spectrophotometer "CM-5" manufactured by Konica Minolta Co., Ltd. was used as the apparatus, and the measurement conditions were a measurement diameter of 30 mm and SCE.
A calibration glass for petri dish measurement "CM-A212" was fitted into the measurement part, and a zero calibration box "CM-A124" was placed over it to perform zero calibration, followed by white calibration using the built-in white calibration plate. . Then, using a white calibration plate "CM-A210", L * is 99.40 ± 0.05, a * is 0.03 ± 0.01, b * is -0.43 ± 0.01 , YI was -0.58±0.01.
YI was measured by filling a cylindrical glass container with an inner diameter of 30 mm and a height of 50 mm with pellets to a depth of about 40 mm. The operation of taking out the pellets from the glass container and measuring again was repeated twice, and the average value of the measured values of a total of three times was used.

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

[Molten color of bisphenol A]
For the molten color of bisphenol A, put 20 g of bisphenol C in a test tube "P-24" (24 mmφ x 200 mm) manufactured by Nichiden Rika Glass Co., Ltd., melt at 175 ° C. for 30 minutes, and use "SE6000" manufactured by Nippon Denshoku Industries Co., Ltd. was used to measure the Hazen color number.

[Example 1]
In a jacketed separable flask equipped with a Dimroth condenser, a stirring blade, and a thermometer, under a nitrogen atmosphere, 20 g of methanol (20 g ÷ 32 g / mol = 0.6 mol, molar ratio of methanol to 1 mol of repeating units of polycarbonate resin = 0.6 mol ÷ 0.3 mol = 2.0), 220 g of dimethyl malonate, and 4 g of sodium phenoxide, and then 80 g of polycarbonate resin (since the molecular weight of the repeating unit of the polycarbonate resin is 254 g/mol, the repeating unit = 80 g/254 g/mol = 0.31 mol) was added at room temperature (liquid volume: 20 g + 220 g + 4 g + 80 g = 324 g).
After that, the jacket temperature was raised to 120°C. When the temperature reached 120° C., undissolved polycarbonate resin was found in the reaction liquid (it was in the form of a slurry), and internal reflux occurred. The mixture was reacted for 3 hours while maintaining the jacket temperature at 120° C. to obtain a uniform reaction liquid.
When the composition of a part of the obtained reaction solution was confirmed by high-performance liquid chromatography, bisphenol A was found to be 20.5% by mass (20.5/100 x 324 g/228 g/mol/0.3 mol x 100 = 97 mol %).

[Example 2]
In a jacketed separable flask equipped with a Dimroth condenser, a stirring blade, and a thermometer, under a nitrogen atmosphere, 20 g of methanol (20 g ÷ 32 g / mol = 0.6 mol, molar ratio of methanol to 1 mol of repeating units of polycarbonate resin = 0.6 mol ÷ 0.3 mol = 2.0), 220 g of dimethyl malonate, and 1 g of potassium hydroxide, and then 80 g of polycarbonate resin (since the molecular weight of the repeating unit of polycarbonate resin is 254 g / mol, Unit moles = 80 g/254 g/mol = 0.31 mol) was added at room temperature (liquid volume: 20 g + 220 g + 1 g + 80 g = 321 g).
After that, the jacket temperature was raised to 120°C. When the temperature reached 120° C., undissolved polycarbonate resin was found in the reaction liquid (it was in the form of a slurry), and internal reflux occurred. The mixture was reacted for 3 hours while maintaining the jacket temperature at 120° C. to obtain a uniform reaction liquid.
When the composition of a portion of the obtained reaction solution was confirmed by high-performance liquid chromatography, bisphenol A was found to be 19.7% by mass (19.7/100 x 321 g/228 g/mol/0.3 mol x 100 = 92 mol %).

[Example 3]
In a jacketed separable flask equipped with a Dimroth condenser, a stirring blade, and a thermometer, under a nitrogen atmosphere, 20 g of methanol (20 g ÷ 32 g / mol = 0.6 mol, molar ratio of methanol to 1 mol of repeating units of polycarbonate resin = 0.6 mol ÷ 0.3 mol = 2.0), 120 g of ethylene diacetate, and 4 g of sodium phenoxy are added, and then 80 g of polycarbonate resin (since the molecular weight of the repeating unit of the polycarbonate resin is 254 g/mol, the repeating unit = 80 g/254 g/mol = 0.31 mol) was added at room temperature (liquid volume was 520 g + 120 g + 4 g + 80 g = 224 g).
After that, the jacket temperature was raised to 120°C. Undissolved polycarbonate resin was found in the reaction liquid when the temperature reached 120° C. (it was in the form of a slurry). The mixture was reacted for 3 hours while maintaining the jacket temperature at 120° C. to obtain a uniform reaction liquid.
A part of the obtained reaction solution was checked for composition by high-performance liquid chromatography, and bisphenol A was found to be 29.4% by mass (29.4/100 x 224 g/228 g/mol/0.3 mol x 100 = 96 mol %).

[Example 4]
In a jacketed separable flask equipped with a Dimroth condenser, a stirring blade, and a thermometer, 48 g of butanol (48 g ÷ 74 g / mol = 0.6 mol, molar ratio of methanol to 1 mol of repeating units of polycarbonate resin = 1.6 mol ÷ 0.3 mol = 2.0), 240 g of butyl acetate, and 4 g of sodium phenoxide, and then 80 g of polycarbonate resin (since the molecular weight of the repeating unit of polycarbonate resin is 254 g/mol, the number of repeating units is mol = 80 g/254 g/mol = 0.3 mol) was added at room temperature (liquid volume was 48 g + 240 g + 4 g + 80 g = 372 g).
After that, the jacket temperature was raised to 120°C. Undissolved polycarbonate resin was found in the reaction liquid when the temperature reached 120° C. (it was in the form of a slurry). The mixture was reacted for 3 hours while maintaining the jacket temperature at 120° C. to obtain a uniform reaction liquid.
When the composition of a part of the obtained reaction solution was confirmed by high-performance liquid chromatography, bisphenol A was found to be 14.1% by mass (14.1/100 x 372 g/228 g/mol/0.3 mol x 100 = 77 mol %).

[Example 5]
In a jacketed separable flask equipped with a Dimroth condenser, a stirring blade, and a thermometer, 48 g of butanol (48 g ÷ 74 g / mol = 0.6 mol, molar ratio of methanol to 1 mol of repeating units of polycarbonate resin = 1.6 mol ÷ 0.3 mol = 2.0), 240 g of butyl acetate, and 4 g of triethylamine, and then 80 g of polycarbonate resin (Since the molecular weight of the repeating unit of the polycarbonate resin is 254 g / mol, the mol of the repeating unit (Number = 80 g/254 g/mol = 0.3 mol) was added at room temperature (liquid volume was 48 g + 240 g + 4 g + 80 g = 372 g).
After that, the jacket temperature was raised to 120°C. Undissolved polycarbonate resin was found in the reaction liquid when the temperature reached 120° C. (it was in the form of a slurry). The mixture was reacted for 3 hours while maintaining the jacket temperature at 120° C. to obtain a uniform reaction liquid.
When the composition of a part of the obtained reaction solution was confirmed by high-performance liquid chromatography, bisphenol A was found to be 10.3% by mass (10.3/100 x 372 g/228 g/mol/0.3 mol x 100 = 56 mol %).

[Comparative Example 1]
In a jacketed separable flask equipped with a Dimroth condenser, a stirring blade, and a thermometer, under a nitrogen atmosphere, 80 g of methanol (80 g ÷ 32 g / mol = 2.5 mol, molar ratio of methanol to 1 mol of repeating units of polycarbonate resin = 2.5 mol ÷ 0.31 mol = 8.1), and 1 g of potassium hydroxide are added, and then 80 g of polycarbonate resin (Since the molecular weight of the repeating unit of the polycarbonate resin is 254 g / mol, the number of moles of the repeating unit = 80 g/254 g/mol=0.31 mol) was added at room temperature (liquid volume was 80 g+1 g+80 g=161 g).
After that, the jacket temperature was raised to 120°C. Before reaching 120° C., it was confirmed that methanol had evaporated and that decomposition had not progressed.

In Examples 1 to 5 and Comparative Example 1, the catalyst, alkyl ester, aliphatic alcohol, and bisphenol A formation rate are summarized in Table 1. From Table 1, it can be seen that polycarbonate can be decomposed at normal pressure by using an alkyl ester.

[Example 6]
The reaction solution obtained in Example 1 was neutralized by adding 70% by mass of sulfuric acid. The resulting liquid was filtered through a glass filter to remove sodium sulfate and obtain a filtrate.
The obtained filtrate was transferred to a distillation apparatus equipped with a thermometer, a stirring blade, a distillation tube, and a pressure regulator. The pressure was changed from normal pressure (101.33 kPa) to 16.00 kPa, and while observing the amount of distillation, methanol and dimethyl malonate were extracted as fractions to obtain a bottom residue. To the obtained still residue, 280 g of toluene was added to obtain a uniform solution at 80°C. After that, the temperature was gradually lowered to 5° C. to obtain a slurry liquid. The resulting slurry liquid was filtered using a centrifugal separator to obtain a cake.

The whole amount of the obtained cake was supplied to a jacketed separable flask equipped with a Dimroth condenser, a stirring blade and a thermometer under a nitrogen atmosphere. After that, 200 g of toluene was supplied to obtain a slurry liquid. The resulting slurry liquid was heated to 80° C. to form a uniform solution. The homogeneous solution obtained was washed with 100 g of demineralized water three times. After that, the temperature was lowered to 5° C. to obtain a slurry liquid. The resulting slurry liquid was filtered using a centrifugal separator to obtain a fine cake. Using an evaporator equipped with an oil bath, the entire amount of the fine cake was dried at an oil bath temperature of 85° C. and 20.00 kPa for 3 hours to obtain 25 g of a solid. The obtained solid was confirmed by high performance liquid chromatography to be bisphenol A with a purity of 99.9%.

10.00 g (0.04 mol) of the obtained bisphenol A, 9.95 g (0.05 mol) of diphenyl carbonate and 400 ppm by mass were placed in a 45 mL glass reactor equipped with a stirrer and a distillation tube. 18 μL of a cesium carbonate aqueous solution was added. The reaction vessel made of glass was evacuated to about 100 Pa, and then the operation of restoring the pressure to atmospheric pressure with nitrogen was repeated three times to replace the inside of the reaction vessel with nitrogen. After that, the reactor was immersed in an oil bath at 220° C. to dissolve the contents.

The rotation speed of the stirrer was set to 100 times per minute, and the pressure in the reactor was increased to 101 in absolute pressure over 40 minutes while distilling off the phenol by-product of the oligomerization reaction of bisphenol A and diphenyl carbonate in the reactor. The pressure was reduced from 3 kPa to 13.3 kPa.

Subsequently, the pressure in the reactor was maintained at 13.3 kPa, and transesterification was carried out for 80 minutes while further distilling off phenol.

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

After that, the absolute pressure of the reactor was reduced to 30 Pa, and a polycondensation reaction was carried out. The polycondensation reaction was terminated when the stirrer in the reaction vessel reached a predetermined stirring power. The time from raising the temperature to 290° C. to completing the polymerization was 120 minutes.

Subsequently, the pressure in the reactor was restored to 101.3 kPa in terms of absolute pressure with nitrogen, and then increased to 0.2 MPa in terms of gauge pressure, and the polycarbonate resin was extracted from the reactor to obtain a polycarbonate resin. The obtained polycarbonate resin had a viscosity average molecular weight (Mv) of 27,100.

According to the present invention, bisphenol can be obtained from waste plastic or the like using chemical recycling. Furthermore, it is industrially useful because it can be used to produce polycarbonate resins and epoxy resins.

Claims (15)

Polycarbonate resin,
A method for producing bisphenol by decomposing it in the presence of an alkyl ester, an aliphatic alcohol and a catalyst. 2. The method for producing bisphenol according to claim 1, wherein the catalyst is selected from the group consisting of alkali metal hydroxides, alkali metal alkoxides, alkali metal carbonates, alkali metal oxides, alkylamines and pyridines. . The alkali metal hydroxide is sodium hydroxide or potassium hydroxide,
the alkali metal carbonate is sodium carbonate, potassium carbonate, sodium hydrogen carbonate or potassium hydrogen carbonate;
the alkali metal alkoxide is sodium phenoxide or sodium methoxide,
3. The method for producing bisphenol according to claim 2, wherein the alkali metal oxide is sodium oxide or potassium oxide. 3. The method for producing bisphenol according to claim 2, wherein the alkylamine is represented by the following formula (I) or the following formula (II).

In formula (I), R ^A represents an alkyl group having 1 to 3 carbon atoms, and R ^B to R ^C each independently represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.

In formula (II), R ^D to R ^G each independently represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and m represents an integer of 1 to 6. 5. The method for producing bisphenol according to any one of claims 1 to 4, wherein said alkyl ester is any one selected from the group consisting of methyl ester, ethyl ester, butyl ester and glycol ester. The method for producing bisphenol according to any one of claims 1 to 5, wherein the bisphenol is 2,2-bis(4-hydroxyphenyl)propane. The method for producing bisphenol according to any one of claims 1 to 6, wherein the decomposition temperature for decomposing the polycarbonate resin is 150°C or less. The method for producing bisphenol according to any one of claims 1 to 7, wherein the alkyl ester has 2 or more and 6 or less carbon atoms. 9. The method for producing bisphenol according to any one of claims 1 to 8, wherein said aliphatic alcohol is any one selected from the group consisting of methanol, ethanol, butanol and ethylene glycol. 10. The method for producing bisphenol according to any one of claims 1 to 9, comprising the following Step A, Step B1 and Step C1.
Step A: Step of decomposing the polycarbonate resin in the presence of the alkyl ester, the aliphatic alcohol and the catalyst to obtain a bisphenol-containing polycarbonate decomposition solution Step B1: Concentrating the polycarbonate decomposition solution obtained in Step A to obtain a concentrated liquid Step C1: An aromatic hydrocarbon is supplied to the concentrated liquid obtained in the step B1 and crystallized to precipitate bisphenol to obtain a slurry containing bisphenol. Step of solid-liquid separation of slurry to obtain bisphenol 10. The method for producing bisphenol according to any one of claims 1 to 9, comprising the following Step A, Step B2 and Step C2.
Step A: Step of decomposing the polycarbonate resin in the presence of the alkyl ester, the aliphatic alcohol and the catalyst to obtain a bisphenol-containing polycarbonate decomposition solution Step B2: The polycarbonate decomposition solution obtained in Step A and the aroma removing the alkyl ester and the aliphatic alcohol from the solution containing the aromatic monoalcohol to obtain a solution containing bisphenol and the aromatic monoalcohol Step C2: recovering the bisphenol from the solution containing the bisphenol and the aromatic monoalcohol process A method for producing a recycled polycarbonate resin, comprising obtaining bisphenol through the method for producing bisphenol according to any one of claims 1 to 11 and then producing a recycled polycarbonate resin using a bisphenol raw material containing the bisphenol. A method for producing an epoxy resin, comprising obtaining bisphenol through the method for producing bisphenol according to any one of claims 1 to 11, and then producing an epoxy resin using a polyhydric hydroxy compound raw material containing the bisphenol. Manufacture of an epoxy resin, wherein an epoxy resin is obtained through the method for manufacturing an epoxy resin according to claim 13, and then an epoxy resin raw material containing the epoxy resin and a polyhydric hydroxy compound raw material are further reacted to manufacture an epoxy resin. Method. An epoxy resin is obtained through the method for producing an epoxy resin according to claim 13 or 14, an epoxy resin composition containing the epoxy resin and a curing agent is obtained, and the epoxy resin composition is cured to cure the epoxy resin. A method for producing a cured epoxy resin product.