WO2023163026A1

WO2023163026A1 - Bisphenol production method, recycled polycarbonate resin production method, epoxy resin production method, cured epoxy resin production method, and bisphenol-alkyl carbonate condensate production method

Info

Publication number: WO2023163026A1
Application number: PCT/JP2023/006417
Authority: WO
Inventors: 馨内山; 員正太田; 幸恵中嶋; 俊雄内堀
Original assignee: 三菱ケミカル株式会社
Priority date: 2022-02-25
Filing date: 2023-02-22
Publication date: 2023-08-31
Also published as: TW202337951A

Abstract

The purpose of the present invention is to provide a bisphenol production method in which, using a highly-versatile catalyst, a polycarbonate resin is decomposed with a high level of reactivity to produce bisphenol.　Provided is a bisphenol production method which carries out a decomposition reaction of a polycarbonate resin in a reaction liquid containing the polycarbonate resin, a dialkyl carbonate, an aliphatic monoalcohol and a catalyst, wherein the molar ratio of the dialkyl carbonate to be used in the decomposition reaction to 1 mole of a bisphenol-derived repeating unit of the polycarbonate resin to be used in the decomposition reaction is 1.8 or more, and the catalyst is one selected from the group consisting of an alkali metal hydroxide, an alkali metal carbonate, an alkali metal alkoxide, an alkali metal oxide, a chain alkylamine and pyridine.

Description

Method for producing bisphenol, method for producing recycled polycarbonate resin, method for producing epoxy resin, method for producing cured epoxy resin, and method for producing bisphenol-alkyl carbonate condensate

The present invention relates to a method for producing bisphenol and a method for producing a bisphenol-alkyl carbonate condensate. More specifically, it relates to a method for producing bisphenol and a method for producing a bisphenol-alkyl carbonate condensate utilizing decomposition of polycarbonate resin. Furthermore, 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. The present invention also relates to a method for producing a cured epoxy resin using the epoxy resin obtained by the method for producing an epoxy resin.

Because plastic is easy, durable, and inexpensive, it is mass-produced not only in Japan but around 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 for 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 method for decomposing 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 a method for obtaining bisphenol A as a reaction solution by subjecting a polycarbonate resin to methanolysis using a guanidine derivative or an amidine derivative as a catalyst. Non-Patent Document 2 discloses methanolysis of a polycarbonate resin using methyl carbonate (tetramethylammonium) as a catalyst.

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

Aliphatic monoalcohols are usually used in the decomposition method using alcoholysis of polycarbonate resin. 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.

In addition, 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.

Furthermore, the method of Non-Patent Document 1 uses a guanidine derivative or an amidine derivative as a catalyst to decompose the polycarbonate resin. These guanidine derivatives and amidine derivatives cannot be easily removed by washing with water because they have a high affinity for both oil and water. Moreover, since these compounds have high boiling points of 150° C. or higher, they are not easily distilled off. Furthermore, since these compounds are lightly colored yellow, it is necessary to perform column chromatography purification and extraction using diethyl ether with a low flash point for purification. Therefore, in order to obtain bisphenol A from a polycarbonate resin, there is a problem that it is industrially unsuitable because it is necessary to take complicated steps.

The method of Non-Patent Document 2 also requires the use of a special catalyst, and like the method of Non-Patent Document 1, it is necessary to take complicated steps to obtain bisphenol A from a polycarbonate resin. There was a problem that it was unsuitable for

In any of the above-described decomposition methods of polycarbonate resins using aliphatic monoalcohols, further improvements are required, such as requiring high temperature and high pressure decomposition conditions, poor reactivity, and complicated operations. was

In addition, bisphenol A is also used as a raw material for optical materials such as optical polycarbonate resin in some fields. Since optical materials are required to have excellent color tone (transparency), bisphenol A, which is a raw material thereof, is also required to have excellent color tone.

The present invention has been made in view of such circumstances, and can decompose a polycarbonate resin with high reactivity using a highly versatile catalyst even under mild conditions with a small environmental load. It is an object of the present invention to provide a method for producing bisphenol which produces bisphenol with good color tone by using a decomposition method. 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.

Another object of the present invention is to provide a method for producing a bisphenol-alkyl carbonate condensate by utilizing the decomposition method for decomposing the polycarbonate resin.

As a result of intensive studies to solve the above problems, the present inventors have found a decomposition method of decomposing a polycarbonate resin by using a general-purpose catalyst in combination with a dialkyl carbonate and an aliphatic monoalcohol. 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. Furthermore, the inventors have found a method for producing a cured epoxy resin using the epoxy resin obtained by the method for producing an epoxy resin.
Also, a method for producing a bisphenol-alkyl carbonate condensate was found.
That is, the present invention relates to the following inventions.

<1> A method for producing bisphenol by performing a decomposition reaction of the polycarbonate resin in a reaction solution containing a polycarbonate resin, a dialkyl carbonate, an aliphatic monoalcohol, and a catalyst, wherein the bisphenol is derived from the bisphenol of the polycarbonate resin used in the decomposition reaction. The molar ratio of the dialkyl carbonate used in the decomposition reaction to 1 mol of the repeating unit is 1.8 or more, and the catalyst is an alkali metal hydroxide, an alkali metal carbonate, an alkali metal alkoxide, an alkali metal oxide, a chain A method for producing a bisphenol selected from the group consisting of alkylamines and pyridines.
<2> The method for producing bisphenol according to <1>, wherein the reaction liquid is in the form of a slurry.
<3> The method for producing bisphenol according to <1> or <2>, wherein the dialkyl carbonate contains a dialkyl carbonate not derived from the polycarbonate resin.
<4> The method for producing bisphenol according to any one of <1> to <3>, wherein the reaction liquid is prepared by mixing the polycarbonate resin, the dialkyl carbonate, the aliphatic monoalcohol, and the catalyst. .
<5> 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 any one of <1> to <4>, wherein the alkali metal oxide is sodium phenoxide or sodium methoxide, and the alkali metal oxide is sodium oxide or potassium oxide.
<6> The method for producing bisphenol according to any one of <1> to <5>, wherein the chain 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.
<7> The method for producing bisphenol according to any one of <1> to <6>, wherein the dialkyl carbonate is dimethyl carbonate, diethyl carbonate, or dibutyl carbonate.
<8> The method for producing bisphenol according to any one of <1> to <7>, wherein the bisphenol is 2,2-bis(4-hydroxyphenyl)propane.
<9> The method for producing bisphenol according to any one of <1> to <8>, wherein the aliphatic monoalcohol is methanol, ethanol or butanol.
<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 reaction solution containing the polycarbonate resin, the dialkyl carbonate, the aliphatic monoalcohol and the catalyst to obtain a non-slurry polycarbonate decomposition solution containing bisphenol Step B1: A step of concentrating the polycarbonate decomposition solution obtained in step A to obtain a concentrated solution. Step C1: An aromatic hydrocarbon is supplied to the concentrated solution obtained in step B1 to precipitate bisphenol. , a step of obtaining a slurry containing bisphenol, and solid-liquid separation of the obtained slurry to obtain bisphenol <11> Any of the above <1> to <9> having the following step A, step B2 and step C2 A process for the preparation of the described bisphenol.
Step A: Step of decomposing the polycarbonate resin in the reaction solution containing the polycarbonate resin, the dialkyl carbonate, the aliphatic monoalcohol and the catalyst to obtain a non-slurry polycarbonate decomposition solution containing bisphenol Step B2: A step of removing the dialkyl carbonate and the aliphatic monoalcohol from the solution containing the polycarbonate decomposition solution and the aromatic monoalcohol obtained in step A to obtain a solution containing bisphenol and the aromatic monoalcohol Step C2: the above step Step of recovering bisphenol from the solution containing bisphenol and aromatic monoalcohol obtained in B2 <12> The polycarbonate resin is recovered in the reaction solution containing the polycarbonate resin, the dialkyl carbonate, the aliphatic monoalcohol and the catalyst. A first decomposition step of decomposing to obtain a first decomposition solution containing bisphenol, and mixing the first decomposition solution and water to hydrolyze the dialkyl carbonate to regenerate the aliphatic monoalcohol. and a second decomposition step of decomposing the polycarbonate resin to generate bisphenol, wherein the first decomposition step and the second decomposition step are performed continuously, from <1> to <10> The method for producing bisphenol according to any one of the above.
<13> The amount of water mixed with the first decomposition solution is 0.5 mol or more and 1.5 mol or less per 1 mol of repeating units derived from bisphenol in the polycarbonate resin used in the decomposition reaction. The method for producing bisphenol according to <12>.
<14> The aliphatic monoalcohol regenerated in the second decomposition step is separated from the bisphenol as a mixture with the dialkyl carbonate, and the mixture of the aliphatic monoalcohol and the dialkyl carbonate is regenerated in the first decomposition step. The method for producing bisphenol according to <12> or <13>.
<15> The method for producing bisphenol according to any one of <12> to <14>, wherein the reaction liquid is slurry and the first decomposition liquid is not slurry.
<16> The method for producing bisphenol according to any one of <1> to <10> above, wherein a bisphenol-alkyl carbonate condensate represented by the following formula (III), which is a by-product of decomposition of the polycarbonate resin, is further recovered.
In formula (III), R is a methyl group, an ethyl group or a butyl group.
<17> The method for producing a bisphenol according to <16>, wherein in formula (III), R is a methyl group.
<18> After obtaining bisphenol through the method for producing bisphenol according to any one of <1> to <17> above, a bisphenol raw material containing the bisphenol is used to produce a recycled polycarbonate resin. Production method.
<19> Epoxy resin production, wherein bisphenol is obtained through the method for producing bisphenol according to any one of <1> to <17>, and then an epoxy resin is produced using a polyhydric hydroxy compound raw material containing the bisphenol. Production method.
<20> After the epoxy resin is obtained through the method for producing an epoxy resin according to <19>, 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.
<21> An epoxy resin is obtained through the method for producing an epoxy resin according to <19> or <20> above, 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.
<22> A method for producing a bisphenol-alkyl carbonate condensate represented by the following formula (III), wherein the polycarbonate resin is decomposed in a reaction solution containing a polycarbonate resin, a dialkyl carbonate, an aliphatic monoalcohol, and a catalyst, wherein the catalyst is , an alkali metal hydroxide, an alkali metal carbonate, an alkali metal alkoxide, an alkali metal oxide, a chain alkylamine and a pyridine.
In formula (III), R is a methyl group, an ethyl group or a butyl group.

According to the present invention, bisphenol is produced by using a decomposition method that can decompose polycarbonate resin with high reactivity using a general-purpose catalyst even under mild conditions with a small environmental load. A manufacturing method is provided. According to the method for producing bisphenol of the present invention, bisphenol with good color tone can be obtained.
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 bisphenol-alkyl carbonate condensate, wherein the bisphenol-alkyl carbonate condensate is produced by utilizing the decomposition method of decomposing the polycarbonate 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 is a method for producing bisphenol, wherein the decomposition reaction of the polycarbonate resin is performed in a reaction solution containing a polycarbonate resin, a dialkyl carbonate, an aliphatic monoalcohol, and a catalyst, and the catalyst is an alkali metal hydroxide or an alkali metal. A method for producing a bisphenol selected from the group consisting of carbonates, alkali metal alkoxides, alkali metal oxides, chain alkylamines and pyridines (hereinafter referred to as the "method for producing a bisphenol of the present invention") There is.)

The method for producing bisphenol of the present invention decomposes a polycarbonate resin in the presence of a dialkyl carbonate, an aliphatic monoalcohol and a specific catalyst. By using a dialkyl carbonate and an aliphatic alcohol together, the dialkyl carbonate swells the polycarbonate resin and increases the contact area with the aliphatic monoalcohol, which accelerates the dissolution rate and decomposition rate. Even if there is, it is thought that it will be easily decomposed.

In the method for producing bisphenol of the present invention, the molar ratio of the dialkyl carbonate used in the decomposition reaction (that is, the charged molar ratio) to 1 mol of repeating units derived from bisphenol in the polycarbonate resin used in the decomposition reaction is 1.5. 8 or more. As a result, the dissolution rate and decomposition rate of the polycarbonate resin do not decrease as will be described later, and the reaction can be carried out efficiently.

In addition, the dispersibility of the polycarbonate resin in the dialkyl carbonate is very good, and by using the dialkyl carbonate, the polycarbonate resin swells and can be easily crushed into fine particles and dispersed. The dispersed polycarbonate resin gradually dissolves in the dialkyl carbonate and is decomposed. A dialkyl carbonate is more likely to undergo a decomposition reaction at the solid-liquid interface than a solvent that leaves the polycarbonate resin in the form of lumps. Therefore, in the method for producing bisphenol of the present invention, it is preferable to prepare a slurry-like reaction liquid in which the polycarbonate resin is dispersed, and to decompose the polycarbonate resin in the slurry-like reaction liquid.

By decomposing the polycarbonate resin in the slurry-like reaction liquid, only the dissolved polycarbonate resin participates in the decomposition reaction, making it easy to control the reaction and stably decomposing the polycarbonate resin. As the decomposition reaction progresses, the polycarbonate resin is completely dissolved, and the reaction liquid (decomposition liquid) at the end of the decomposition reaction is no longer a slurry in which the polycarbonate resin is dispersed, and is not a slurry in which the generated bisphenol is dissolved. becomes liquid. In the present application, the range of slurry at the start of polycarbonate decomposition is defined by filtering the reaction liquid using a filter with an opening of 1 mm or less, and the solid concentration of the filtered polycarbonate resin is 5 mass with respect to the reaction liquid. % or more. In addition, as a range that is not slurry at the end of the decomposition reaction, the decomposition solution is filtered using a filter with an opening of 1 mm or less, and the solid concentration of the filtered polycarbonate resin is less than 5% by mass relative to the decomposition solution. is preferably

(Polycarbonate resin (PC))
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 has a repeating unit derived from bisphenol represented by the general formula (1) (hereinafter sometimes simply referred to as "repeating unit"). A polymer containing

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.

^R5 and ^R6 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 are bonded or bridged to each other between the two groups, cycloalkylidene group, fluorenylidene group (fluorene 9,9-diyl group), xanthenylidene group (xanthene 9,9-diyl group), thioxantheni A lidene group (thioxanthene 9,9-diyl group) or the like may be formed. For example, cycloalkylidene groups include cyclopropylidene, cyclobutylidene, cyclopentylidene, cyclohexylidene, 3,3,5-trimethylcyclohexylidene, cycloheptylidene, cyclooctylidene, cyclononylidene, cyclodecylidene, cycloundecylidene, cyclododecylidene 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 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.

That is, 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").

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

As raw materials for the method for producing bisphenol of the present invention, not only polycarbonate resins alone, but also compositions containing resins other than polycarbonate resins, 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.

Also, the 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 plastic is preferable. 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 used after washing, crushing, crushing, etc. as appropriate. 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.

(dialkyl carbonate)
One of the characteristics of the method for producing bisphenol of the present invention is to use a dialkyl carbonate. Dialkyl carbonate is preferably dimethyl carbonate, diethyl carbonate or dibutyl carbonate.

Among them, dimethyl carbonate and diethyl carbonate are preferable because they have relatively low boiling points and can be easily removed after the decomposition reaction and can reduce the purification load.

The dialkyl carbonate includes dialkyl carbonate not derived from polycarbonate resin. That is, when a polycarbonate resin is decomposed in the presence of an aliphatic monoalcohol, a dialkyl carbonate is produced as the polycarbonate resin is decomposed. The dialkyl carbonate is used by supplying it to a reactor for decomposing the polycarbonate resin.

The "dialkyl carbonate not derived from the polycarbonate resin" means dialkyl carbonate not derived from the polycarbonate resin used at the same time, and is the dialkyl carbonate supplied to the reaction vessel. In the method for producing bisphenol of the present invention, the dialkyl carbonate generated by decomposition of the polycarbonate resin may be recycled to the next decomposition reaction as dialkyl carbonate not derived from the polycarbonate resin used simultaneously.

If the amount of dialkyl carbonate to be used is small relative to the amount of polycarbonate resin to be used, the amount of solid (polycarbonate resin) to the liquid at the initial stage of the reaction will be large, resulting in poor mixing, dissolution rate and decomposition rate of polycarbonate resin. tends to be delayed. Therefore, the molar ratio of the dialkyl carbonate used to 1 mol of the repeating unit of the polycarbonate resin used is 1.8 or more. It is more preferably 1.9 or more, and more preferably 2.0 or more. In addition, when the amount of dialkyl carbonate used relative to the polycarbonate resin used is large, the production efficiency tends to deteriorate. Therefore, the molar ratio of the dialkyl carbonate to be used is preferably 100 or less, more preferably 70 or less, and even more preferably 50 or less to 1 mol of the repeating unit of the polycarbonate resin to be used.

For example, the molar ratio of the dialkyl carbonate used in the decomposition reaction to 1 mol of the repeating unit of the polycarbonate resin used in the decomposition reaction is preferably 1.8 or more and 100 or less, more preferably 1.9 or more and 70 or less, and 2.0. 50 or less is more preferable. Also, the molar ratio may be 2.5 or more and 45 or less, or 3.0 or more and 40 or less.

In the present application, the amount (mole or mass) of the polycarbonate resin used for the decomposition reaction means the amount of the polycarbonate resin charged (the amount supplied to the reaction vessel). Also, the "polycarbonate resin used in the decomposition reaction" may be simply described as "the polycarbonate resin used". The same is true for other materials such as dialkyl carbonates, fatty alcohols and catalysts.

The number of moles of the repeating unit of the polycarbonate resin used is the value obtained by dividing the mass of the polycarbonate resin used (mass of preparation) by the molecular weight of the repeating unit derived from bisphenol. In the case of the polycarbonate resin represented by the general formula (1), the repeating unit derived from bisphenol has a structure of n=1 in the general formula (1). The number of moles of the dialkyl carbonate to be used is the value obtained by dividing the mass of the dialkyl carbonate to be used (mass of charge) by the molecular weight of the dialkyl carbonate. Therefore, the molar ratio of the dialkyl carbonate to be used with respect to 1 mol of the repeating unit of the polycarbonate resin to be used is "(mass of dialkyl carbonate to be used [g]/molecular weight of dialkyl carbonate [g/mol])/(molecular weight of polycarbonate resin to be used mass [g]/molecular weight of repeating unit of polycarbonate resin [g/mol])”.

Since dialkyl carbonate is generated as the polycarbonate resin decomposes, the dialkyl carbonate contained in the reaction solution at the end of the reaction is the dialkyl carbonate not derived from the polycarbonate resin (the dialkyl carbonate supplied to the reaction tank) and the polycarbonate resin. dialkyl carbonate (dialkyl carbonate produced by alcoholysis of polycarbonate resin). Part of the dialkyl carbonate contained in the reaction solution at the end of the reaction is dialkyl carbonate not derived from the polycarbonate resin. The molar ratio of the dialkyl carbonate (total of the dialkyl carbonate used and the dialkyl carbonate produced) at the end of the reaction to 1 mol of the repeating unit of the polycarbonate resin used is the ratio of the dialkyl carbonate used to 1 mol of the repeating unit of the polycarbonate resin used. larger than the molar ratio. The molar ratio of the dialkyl carbonate at the end of the reaction (total of the dialkyl carbonate used and the dialkyl carbonate produced) to 1 mol of the repeating unit of the polycarbonate resin used is preferably 2.8 or more, more preferably 2.81 or more. 3.3 or more is more preferable, and 3.8 or more is still more preferable.

(aliphatic monoalcohol)
One of the characteristics of the method for producing bisphenol of the present invention is that an aliphatic monoalcohol is used. 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.

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

In addition, it is preferable to use an aliphatic monoalcohol that has the same alkyl group as the dialkyl carbonate used. For example, it is preferable to use methanol when dimethyl carbonate is used as the dialkyl carbonate, ethanol is preferably used when diethyl carbonate is used as the dialkyl carbonate, and butanol is used when dibutyl carbonate is used as the dialkyl carbonate. is preferred.

If the amount of aliphatic monoalcohol used is small relative to the amount of polycarbonate resin used, the polycarbonate resin will be difficult to decompose and the decomposition rate will decrease, resulting in a longer decomposition time and a tendency to deteriorate efficiency. It is in. Therefore, the molar ratio of the aliphatic monoalcohol to 1 mol of the repeating unit of the polycarbonate resin ((mass of the aliphatic monoalcohol used [g] / molecular weight of the aliphatic monoalcohol [g / mol]) / (of the polycarbonate resin to be used Mass [g]/molecular weight of repeating unit of polycarbonate resin [g/mol])) is preferably 0.1 or more, more preferably 0.5 or more, and still more preferably 1.0 or more. Moreover, when the amount of the aliphatic monoalcohol used relative to the polycarbonate resin used is large, the production efficiency tends to deteriorate. Therefore, the molar ratio of the aliphatic monoalcohol to 1 mol of the repeating unit of the polycarbonate resin is preferably 20.0 or less, more preferably 15.0 or less, and even more preferably 10.0 or less.

The decomposition of polycarbonate resin can be controlled by adjusting the amount of aliphatic monoalcohol and the reaction time. When the structure of the decomposition product to be obtained is controlled by the amount of the aliphatic monoalcohol, in order to efficiently produce the dialkyl carbonate, the molar ratio of the aliphatic monoalcohol to 1 mol of the repeating unit of the polycarbonate resin is 2.0 or more is preferable, 2.1 or more is more preferable, and 2.2 or more is still more preferable. In order to efficiently produce a bisphenol-alkyl carbonate condensate (sometimes simply referred to as a "condensate"), the molar ratio of the aliphatic monoalcohol to 1 mol of the repeating unit of the polycarbonate resin is 2. It is preferably less than 0.0, and may be 1.95 or less, 1.9 or less, 1.85 or less, or 1.8 or less.

For example, in order to efficiently produce a dialkyl carbonate, the molar ratio of the aliphatic monoalcohol to 1 mol of the repeating unit of the polycarbonate resin is 2.0 or more and 20.0 or less, 2.1 or more and 15.0 or less, or 2.1 or more and 15.0 or less. It is preferable to make it 2 or more and 10.0 or less. Further, in order to efficiently produce the bisphenol-alkyl carbonate condensate, the molar ratio of the aliphatic monoalcohol to 1 mol of the repeating unit of the polycarbonate resin is 0.1 or more and less than 2.0, 0.5 or more and 1.95. or less, or 1.0 or more and 1.9 or less.

The molar ratio of the aliphatic monoalcohol used to the dialkyl carbonate used (the number of moles of the aliphatic monoalcohol used/the number of moles of the dialkyl carbonate used) is preferably 0.01 or more, more preferably 0.05 or more. preferable. Also, the molar ratio is preferably 15.0 or less, more preferably 10.0 or less, more preferably 8.0 or less, and more preferably 5.0 or less. If the molar ratio of the aliphatic monoalcohol used to the dialkyl carbonate used is small, the polycarbonate resin will be difficult to decompose, or the decomposition rate will decrease, resulting in a prolonged decomposition time. Further, when the molar ratio is large, separation of the aliphatic monoalcohol and the dialkyl carbonate becomes complicated when recovering the dialkyl carbonate.

For example, the molar ratio of the aliphatic monoalcohol used to the dialkyl carbonate used (molar ratio of charge) is 0.01 or more and 10.0 or less, 0.05 or more and 8.0 or less, 0.1 or more and 6.0 or less. , 0.15 to 5.0 or 0.2 to 3.0. Also, the molar ratio may be 0.25 or more and 2.5 or less, or 0.3 or more and 1.8 or less.

(catalyst)
The method for producing bisphenol of the present invention further uses a catalyst selected from the group consisting of alkali metal hydroxides, alkali metal carbonates, alkali metal alkoxides, alkali metal oxides, chain alkylamines and pyridine. That is one of the characteristics.

Above all, the catalyst is preferably one selected from the group consisting of alkali metal hydroxides, alkali metal carbonates, alkali metal alkoxides and alkali metal oxides, more preferably alkali metal hydroxides or alkali metal carbonates. The use of inorganic metal catalysts such as alkali metal hydroxides and alkali metal carbonates was considered unfavorable because the dialkyl carbonate would decompose. However, the present inventors found that when a polycarbonate resin is decomposed in the presence of a dialkyl carbonate and an aliphatic monoalcohol using an alkali metal hydroxide, an alkali metal carbonate, or the like as a catalyst, the polycarbonate resin decomposes at a high reaction rate, It was found that bisphenol with good color tone can be obtained. Further, by using any one selected from the group consisting of alkali metal hydroxides, alkali metal carbonates, alkali metal alkoxides and alkali metal oxides, odor is less likely to occur, so it is preferable to use these catalysts. .

[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 used to 1 mol of the repeating unit of the polycarbonate resin used ((mass of alkali metal hydroxide used [g]/molecular weight of alkali metal hydroxide [g/mol]) /(mass [g] of polycarbonate resin used/molecular weight [g/mol] of repeating unit of polycarbonate resin)) 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 be used to 1 mol of the repeating unit of the polycarbonate resin to be used 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, and more preferably sodium carbonate or potassium carbonate.

If the amount of alkali metal carbonate used relative to the polycarbonate resin used is small, the decomposition rate will be slow, the decomposition time will be prolonged, and efficiency will tend to deteriorate. Therefore, the molar ratio of the alkali metal carbonate used to 1 mol of the repeating unit of the polycarbonate resin used ((mass of the alkali metal carbonate used [g] / molecular weight of the alkali metal carbonate [g / mol]) / (used The mass [g] of the polycarbonate resin/molecular weight [g/mol] of the repeating unit of the polycarbonate resin)) 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 used to 1 mol of the repeating unit of the polycarbonate resin used 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.

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 efficiency will tend to deteriorate. Therefore, the molar ratio of the alkali metal alkoxide used to 1 mol of the repeating unit of the polycarbonate resin used ((mass of alkali metal alkoxide used [g] / molecular weight of alkali metal alkoxide [g / mol]) / (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 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 used to 1 mol of the repeating unit of the polycarbonate resin used 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 alkali metal oxide used relative to the polycarbonate resin used is small, the decomposition rate will be slow, the decomposition time will be prolonged, and efficiency will tend to deteriorate. Therefore, the molar ratio of the alkali metal oxide to be used to 1 mol of the repeating unit of the polycarbonate resin to be used ((mass of the alkali metal oxide to be used [g] / molecular weight of the alkali metal oxide [g / mol]) / (used The mass [g] of the polycarbonate resin/molecular weight [g/mol] of the repeating unit of the polycarbonate resin)) 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 be used to 1 mol of the repeating unit of the polycarbonate resin to be used is preferably 1 or less, more preferably 0.9 or less, and even more preferably 0.8 or less.

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

The chain alkylamine is preferably a chain alkyl monoamine or a chain alkyl diamine.

Among the chain alkyl monoamines, the monoalkyl monoamine, which is a primary amine, reacts with the carbonate-bonded portion of the polycarbonate resin to generate isocyanate, and is more preferably a dialkyl monoamine, which is a secondary amine, or a trialkyl monoamine, which is a tertiary amine. is. 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 chain 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 chain alkylamines represented by general formula (I) include methylamine, ethylamine, propylamine, dimethylamine, diethylamine, trimethylamine, triethylamine, and the like.

The chain 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 chain 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 chain alkylamine used relative to the polycarbonate resin used is small, the decomposition rate will be slow, the decomposition time will be prolonged, and efficiency will tend to deteriorate. Therefore, the molar ratio of N of the amino group of the chain alkylamine to be used with respect to 1 mol of the repeating unit of the polycarbonate resin to be used ((mass of alkylamine to be used [g] × number of N of amino group / number of chain alkylamine Molecular weight [g/mol])/(mass of polycarbonate resin to be used [g]/molecular weight of repeating unit of polycarbonate resin [g/mol])) is preferably 0.0005 or more, more preferably 0.0007 or more, 0.001 or more is more preferable. For example, it can be 0.01 or more, or 0.1 or more. If the amount of chain alkylamine used relative to the polycarbonate resin used is large, amine odor is more likely to occur, and dialkyl carbonates and condensates are less likely to form. Therefore, the molar ratio of N of the amino group of the chain alkylamine used to 1 mol of the repeating unit of the polycarbonate resin used 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, and 0.8 or less, in this 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 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 pyridine to be used per 1 mol of repeating units of the polycarbonate resin to be used ((mass of pyridine to be used [g]/molecular weight of pyridine [g/mol])/(mass of polycarbonate resin to be used [g]/ The molecular weight [g/mol])) of the repeating unit of the polycarbonate resin 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 be used with respect to 1 mol of repeating units of the polycarbonate resin to be used is preferably 4.5 or less, 4.0 or less, 3.0 or less, 2.0 or less, 1.0 or less, 0.9 In the following, the smaller the value in the order of 0.8 or less, the more preferable.

(Preparation of reaction solution)
In the method for producing bisphenol of the present invention, a polycarbonate resin, a dialkyl carbonate (a dialkyl carbonate not derived from a polycarbonate resin), an aliphatic monoalcohol and a catalyst are mixed to prepare a reaction solution. That is, in the method for producing bisphenol of the present invention, a dialkyl carbonate not derived from a polycarbonate resin is supplied to a reaction tank in which the polycarbonate resin is decomposed to prepare a reaction solution.

The mixing order of polycarbonate resin, dialkyl carbonate (dialkyl carbonate not derived from polycarbonate resin), aliphatic monoalcohol and catalyst is not particularly limited. Alternatively, a polycarbonate resin, an aliphatic monoalcohol and a catalyst may be sequentially supplied to the dialkyl carbonate. The polycarbonate resin is preferably fed to the reaction vessel after the dialkyl carbonate and/or the aliphatic monoalcohol so that it can be mixed more uniformly.

(Reaction solution)
The prepared reaction solution (reaction solution at the start of the reaction) contains a polycarbonate resin, a dialkyl carbonate, an aliphatic monoalcohol and a catalyst. At least the reaction immediately after the start of the reaction is preferably carried out with a slurry solution in which the polycarbonate resin is dispersed in the liquid component containing the dialkyl carbonate and the aliphatic monoalcohol. The theoretical slurry concentration in the reaction solution to be prepared (mass of solid content used to prepare the reaction solution/mass of all materials used to prepare the reaction solution) is preferably 0.05 or more, more preferably 0.1 or more. preferable. Moreover, 0.5 or less is preferable and 0.4 or less is more preferable. If the theoretical slurry concentration (concentration of solids) is too low, the decomposition efficiency will decrease, and if the theoretical slurry concentration is too high, poor mixing will occur.

The liquid components in the reaction solution to be prepared are mainly composed of dialkyl carbonate and aliphatic monoalcohol, and the total mass of dialkyl carbonate and aliphatic monoalcohol with respect to the mass of all liquid components is 0.8 or more. 0.9 or more, 0.95 or more, and the like.

The total mass of the polycarbonate resin, dialkyl carbonate, aliphatic monoalcohol and catalyst with respect to the mass of the prepared reaction solution is 0.9 or more, 0.95 or more, 0.98 or more, 0.99 or more. be able to. Moreover, the reaction liquid may be composed of a polycarbonate resin, a dialkyl carbonate, an aliphatic monoalcohol and a catalyst.

When trying to obtain a dialkyl carbonate or a condensate together with bisphenol, if water is included in the prepared reaction solution, the resulting dialkyl carbonate or condensate is likely to be decomposed. Therefore, the content of water in the prepared 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.

The reaction solution is preferably prepared 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, the rate of dissolution of the polycarbonate resin will decrease. In addition, the viscosity of the reaction liquid increases, and poor mixing tends to occur, and uniform mixing may become difficult. 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.

(decomposition reaction)
In the method for producing bisphenol of the present invention, the presence of the dialkyl carbonate, the aliphatic monoalcohol and the catalyst causes cleavage of the carbonate bond portion of the polycarbonate resin, resulting in decomposition. That is, the polycarbonate resin reacts with the aliphatic monoalcohol and is decomposed by alcoholysis. As a result, decomposition products such as bisphenol, dialkyl carbonate, and condensates of bisphenol and dialkyl carbonate are produced. By controlling the amount of dialkyl carbonate and aliphatic monoalcohol and the reaction time, it is possible to control the decomposition reaction such as preferentially producing bisphenol and dialkyl carbonate.

For example, by setting the molar ratio of the aliphatic monoalcohol used to 1 mol of the repeating unit of the polycarbonate resin used to 2.0 or more, the reaction of decomposing the polycarbonate resin into bisphenol and dialkyl carbonate preferentially occurs. . Thereby, bisphenol and dialkyl carbonate can be efficiently obtained.

In addition, the molar ratio of the aliphatic monoalcohol used to 1 mol of the repeating unit of the polycarbonate resin used is less than 2.0, or the reaction time is shortened to produce a condensate of bisphenol and dialkyl carbonate. good too.

In order to prevent the decomposition reaction from proceeding during the preparation of the reaction solution (during the mixing of the polycarbonate resin, dialkyl carbonate (dialkyl carbonate not derived from the polycarbonate resin), aliphatic monoalcohol and catalyst), the concentration of the polycarbonate resin and the reaction solution The reaction solution preparation step and the decomposition reaction step may be clearly separated by controlling the temperature or the like during preparation, but the reaction solution adjustment step and the decomposition reaction 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 since the reaction proceeds sufficiently even under normal pressure, it is preferable to carry it out 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. ), it is preferable to raise the temperature to a predetermined reaction temperature. If the temperature during preparation of the reaction solution is too high, it may become difficult to control the decomposition reaction. It is preferable to raise the temperature of the reaction solution after preparation because the decomposition reaction can proceed stably.

The reaction temperature is appropriately selected according to the type of dialkyl carbonate, the reaction time, etc. However, if the temperature is too high, the aliphatic monoalcohol in the reaction solution will evaporate and the alcoholysis will stop. In addition, when the temperature is low, the solvolysis is difficult to proceed and the reaction rate is lowered, so the time required for decomposition is prolonged. For these reasons, the reaction temperature is preferably 20° C. or higher, and more preferably 30° C. or higher and 40° C. or higher in that order. In addition, 120° C. or less is preferable, and the smaller numerical value is more preferable in the order of 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 20 to 120° C. and normal pressure, more preferably at a reaction temperature of 30 to 110° C. and normal pressure, and at a reaction temperature of 40 to 100° C. and normal pressure. is more preferred.

In addition, when the reaction is carried out at the same temperature as in the preparation of the reaction solution, the reaction temperature is adjusted from the time when the mixing of the polycarbonate resin, dialkyl carbonate, aliphatic monoalcohol and catalyst is completed, for neutralization or for stopping the decomposition reaction. It is the average temperature up to the point at which the distillation operation is 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. .

Also, as will be described later, even when the first decomposition step and the second decomposition step are performed, the reaction temperature in each step is preferably the above reaction temperature. Further, the reaction temperature may be the same or different in the first decomposition step and the second decomposition step.

(reaction time)
The reaction time is appropriately selected according to the theoretical 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, and 20 hours. The shorter the time, in the order of 15 hours or less, 10 hours or less, and 5 hours or less, the more preferable. 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 mixing the polycarbonate resin, dialkyl carbonate, aliphatic monoalcohol, and catalyst to the start of the neutralization and distillation operations for stopping the decomposition reaction. The end point of the reaction time may be determined by tracking the decomposition reaction by liquid chromatography or the like.

When the polycarbonate resin is decomposed by performing the first decomposition step and the second decomposition step, the reaction time is the total time of the first decomposition step and the second decomposition step.

(Decomposition method)
In the method for producing bisphenol of the present invention, it suffices if the polycarbonate resin can be decomposed by alcoholysis. Therefore, after preparing the reaction solution, the decomposition reaction may be carried out until the reaction is completed without additional supply, or during the reaction. Water or the like may be supplied to control the equilibrium of the decomposition reaction.

In order to improve the yield of bisphenol and make it easier to reuse the dialkyl carbonate and the aliphatic monoalcohol, it is preferable to mix water with the reaction solution after the decomposition reaction has progressed to some extent.

[Method for decomposing polycarbonate resin (1)]
For example, as a decomposition method (1) for a polycarbonate resin, a polycarbonate resin is decomposed in a reaction solution containing a polycarbonate resin, a dialkyl carbonate, an aliphatic monoalcohol and a catalyst to obtain a first decomposition solution containing bisphenol. A decomposition step and a second decomposition step of hydrolyzing the dialkyl carbonate by mixing the first decomposition solution and water to regenerate the aliphatic monoalcohol and decomposing the polycarbonate resin to produce bisphenol. and wherein the first decomposition step and the second decomposition step are continuously performed.

By adopting such a method, it is possible to regenerate (generate) an aliphatic monoalcohol by hydrolyzing dialkyl carbonates and condensates produced together with bisphenol while decomposing the polycarbonate resin by alcoholysis. As a result, the equilibrium of the decomposition reaction of the polycarbonate resin shifts, and the decomposition reaction of the polycarbonate resin proceeds more easily.

[First decomposition step]
The first decomposition step is a step of decomposing a polycarbonate resin in a reaction solution containing a polycarbonate resin, a dialkyl carbonate, an aliphatic monoalcohol and a catalyst to obtain a first decomposition solution containing bisphenol. In the first decomposition step, the polycarbonate resin reacts with the aliphatic monoalcohol and is decomposed by alcoholysis, the aliphatic monoalcohol is consumed, and decomposition products such as bisphenol, dialkyl carbonate, and condensates of bisphenol and dialkyl carbonate are produced. do.

In the first decomposition step, the prepared reaction solution is preferably slurry. The theoretical slurry concentration in the reaction solution to be prepared (mass of solid content used to prepare the reaction solution/mass of all materials used to prepare the reaction solution) is preferably 0.05 or more, more preferably 0.1 or more. preferable. Moreover, 0.5 or less is preferable and 0.4 or less is more preferable. If the theoretical slurry concentration (concentration of solid content) is too low, the decomposition efficiency will decrease, and if the theoretical slurry concentration is too high, poor mixing will occur. It is preferable that the slurry in which the polycarbonate resin is dispersed disappears at the end of the first decomposition step. More preferably, the polycarbonate resin is completely dissolved at the end of the first decomposition step, and the first decomposition liquid is not a slurry.

The preparation method and reaction temperature of the reaction solution are as described above. More preferably, 2.2 or more is even more preferable

In the first decomposition step, 0.1 mol of water is added to 1 mol of repeating units of the polycarbonate resin to be used (that is, the amount of polycarbonate resin charged) so that the decomposition product is not hydrolyzed in the first decomposition step. It is preferable that the decomposition reaction is carried out under conditions such as 0.05 mol or less, 0.01 mol or less, or the like. In addition, the water content of the reaction solution to be prepared may be controlled, and the water content of the reaction solution to be prepared is 0.5% by mass or less, 0.1% by mass or less, 0.05% by mass or less, etc. The first decomposition step can be performed as

The reaction time in the first decomposition step is not particularly limited, but when the reaction liquid is slurry at the start of the reaction, it should be at least the time required for the slurry in which the polycarbonate resin is dispersed to disappear and become a non-slurry liquid. preferably. Further, it is more preferable to set the reaction solution to a time longer than at least until the polycarbonate resin is completely dissolved. If the second decomposition step is carried out in the state of a slurry-like reaction liquid, the dissolution rate of the undissolved polycarbonate resin tends to decrease, and decomposition tends to take a long time. For example, the first decomposition step can be 0.1 hours or longer, 0.25 hours or longer, 0.5 hours or longer, 1 hour or longer, and the like.

[Second decomposition step]
In the second decomposition step, the first decomposition solution is mixed with water to hydrolyze the dialkyl carbonate to regenerate the aliphatic monoalcohol, and the polycarbonate resin is decomposed to generate bisphenol. be. In the second decomposition step, the alcoholysis of the polycarbonate resin proceeds along with the hydrolysis of the dialkyl carbonate. At this time, in addition to the unreacted aliphatic monoalcohol, the aliphatic monoalcohol produced by hydrolysis of the dialkyl carbonate can react with the polycarbonate resin, thereby improving the reaction rate of decomposition of the polycarbonate resin. At the end of the second decomposition step, the reaction liquid (decomposition liquid) is a non-slurry liquid in which bisphenol is dissolved. Even if the polycarbonate resin remains at the end of the second decomposition step, the slurry in which the polycarbonate resin is dispersed disappears, leaving a non-slurry liquid. At the end of the second decomposition step, it is preferable that the polycarbonate resin is completely dissolved and the decomposition liquid is not a slurry.

In addition, it is preferable to separate the aliphatic monoalcohol regenerated in the second decomposition step from the bisphenol as a mixture with the dialkyl carbonate, and reuse the mixture of the aliphatic monoalcohol and the dialkyl carbonate in the first decomposition step. In this way, the environmental load becomes lower.

For example, the decomposition liquid obtained in the second decomposition step contains bisphenol, aliphatic monoalcohol and dialkyl carbonate. Aliphatic monoalcohol and dialkyl carbonate can be recovered by distilling the decomposed liquid or a liquid obtained by neutralizing the same. In particular, since dimethyl carbonate and methanol azeotrope, when dimethyl carbonate and methanol are used, a mixture of dimethyl carbonate and methanol can be recovered by distillation. The recovered distillate can be reused for preparing the reaction solution in the first decomposition step.

In the second decomposition step, if the amount of water mixed with the first decomposition solution is too small, the amount of regenerated aliphatic monoalcohol is small, and the effect of accelerating the decomposition of the undecomposed polycarbonate resin is low. On the other hand, if the amount is too large, the amount of the regenerated aliphatic monoalcohol increases, so that the undecomposed polycarbonate resin can be efficiently decomposed. However, when the mixture of the aliphatic monoalcohol and the dialkyl carbonate is recovered in the first decomposition step and reused, the aliphatic monoalcohol becomes excessive, making it difficult to use the entire recovered amount as it is. In particular, since methanol and dimethyl carbonate form an azeotropic composition, it is difficult to obtain each separately by distillation. Therefore, the amount of water mixed with the first decomposition solution is preferably 0.5 mol or more and 1.5 mol or less, more preferably 0.6 mol, per 1 mol of the repeating unit of the polycarbonate resin used. mol or more and 1.4 mol or less, and most preferably 0.7 mol or more and 1.3 mol or less.

The amount of aliphatic monoalcohol and dialkyl carbonate contained in the decomposition solution after the second decomposition step is 80% by mass to 120% by mass relative to the amount used in the first decomposition step (amount charged). It is preferably in the range, more preferably in the range of 90% by mass to 110% by mass. With a composition within this range, even if the mixed liquid of the aliphatic monoalcohol and the dialkyl carbonate is used for the preparation of the reaction liquid in the first decomposition step, it is easy to adjust the reaction liquid to a desired composition. Therefore, it is easy to recycle to the first decomposition step as a mixture of aliphatic monoalcohol and dialkyl carbonate.

[Method for decomposing polycarbonate resin (2)]
When trying to obtain a condensate together with bisphenol, it is preferable to carry out a decomposition reaction so as not to hydrolyze the condensate. In such a case, after preparing the reaction solution, it is preferable to adopt a method in which the decomposition reaction is carried out until the reaction is completed without additionally supplying water. In order to suppress the hydrolysis of the decomposition products, the water content of the reaction solution to be prepared is 0.5% by mass or less, 0.1% by mass or less, or 0.05% by mass or less. It is preferred to carry out the reaction. The amount of water per 1 mol of the repeating unit of the polycarbonate resin used may be controlled, and water is 0.1 mol or less, 0.05 mol or less, or 0.01 mol or less per 1 mol of the repeating unit of the polycarbonate resin used. It can be set as a condition such as mol or less.

(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 a chain alkylamine or pyridine is used as a catalyst, the decomposition reaction can be stopped by distilling off or neutralizing the chain alkylamine or pyridine. In the method of removing the chain 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 chain alkylamine or pyridine is preferably It is a method of distilling off. Moreover, when an alkali metal hydroxide or alkali metal carbonate is used as a catalyst, the decomposition reaction can be stopped by neutralization or the like.

(Bisphenol recovery)
Bisphenol can be recovered from the reaction solution after the decomposition reaction by means such as crystallization or column chromatography 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 dialkyl carbonate and organic solvent may be distilled off before crystallization.

(Recovery of bisphenol-alkyl carbonate condensate)
In the method for producing bisphenol of the present invention, the bisphenol-alkyl carbonate condensate represented by the following formula (III), which is a by-product of the decomposition of the polycarbonate resin, can be further recovered.

In formula (III), R is a methyl group, an ethyl group, or a butyl group, preferably a methyl group.

The recovery (isolation and purification) of the bisphenol-alkyl carbonate condensate can be carried out by a conventional method. Examples include crystallization and purification by column chromatography.

[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 the polycarbonate resin in a reaction solution containing the polycarbonate resin, the dialkyl carbonate, the aliphatic monoalcohol and the catalyst to obtain a polycarbonate decomposition solution containing bisphenol Step B1: Obtained in Step A Step of concentrating the obtained polycarbonate decomposition solution to obtain a concentrate Step C1: An aromatic hydrocarbon is supplied to the concentrate obtained in Step B1 to crystallize to precipitate bisphenol, and a slurry containing bisphenol is obtained. and obtaining bisphenol by solid-liquid separation of the obtained slurry

[Step A]
In step A, for example, any selected from the group consisting of a polycarbonate resin, a dialkyl carbonate, an aliphatic monoalcohol, an alkali metal hydroxide, an alkali metal carbonate, an alkali metal alkoxide, a chain alkylamine and pyridine is stirred for a predetermined period of time. As a result, the polycarbonate resin is decomposed to produce bisphenol, and a bisphenol-containing polycarbonate decomposition solution is obtained. The polycarbonate resin, the dialkyl carbonate, the aliphatic monoalcohol, the type and mixing ratio of the catalyst, the reaction temperature, etc. are as described above.

Further, in step A, it is preferable to decompose the polycarbonate resin in a slurry-like reaction liquid to carry out the reaction. In step A, depending on the purpose, after preparing a slurry-like reaction liquid, the decomposition reaction may be carried out until the reaction is completed without additional supply, or water may be mixed in the middle of the reaction to allow the decomposition reaction to proceed. For example, the balance may be controlled. Theoretical slurry concentration in the reaction solution to be prepared (mass of solid content used in preparation of reaction solution/mass of all materials used in preparation of reaction solution) is preferably 0.05 or more, more preferably 0.1 or more. . Moreover, 0.5 or less is preferable and 0.4 or less is more preferable. If the theoretical slurry concentration (concentration of solid content) is too low, the decomposition efficiency will decrease, and if the theoretical slurry concentration is too high, poor mixing will occur. As the decomposition reaction progresses, the polycarbonate resin dissolves, and the slurry in which the polycarbonate resin is dispersed disappears. At the end of step A, a non-slurry liquid in which bisphenol is dissolved is obtained. Even if the polycarbonate resin remains at the end of step A, it is preferable that the liquid is not a slurry and that the polycarbonate resin is completely dissolved.

[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 concentration of the concentrated liquid is 70% by mass or less, preferably 60% by mass or less, and more preferably 50% by mass or less of the polycarbonate decomposition liquid. . Distillation is preferably carried out so that the concentration of the concentrated liquid is 20% by mass or more, preferably 30% by mass or less, of the polycarbonate decomposition liquid. If the solution is concentrated too much, bisphenol will precipitate and the solution will solidify. For example, distillation can be carried out at a temperature of 50-200° C. and a pressure of 0.1 kPa to 150 kPa.

Also, the polycarbonate decomposition solution may be concentrated after neutralization and washing. Neutralization is performed by mixing a polycarbonate decomposing 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 mixed liquid containing a concentrated liquid and an 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, by solid-liquid separation of the slurry containing bisphenol, bisphenol can be recovered as a solid content. 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 or suspension washing. 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 the polycarbonate resin in a reaction solution containing the polycarbonate resin, the dialkyl carbonate, the aliphatic monoalcohol and the catalyst to obtain a polycarbonate decomposition solution containing bisphenol Step B2: Obtained in Step A A step of removing the dialkyl carbonate and the aliphatic monoalcohol from the solution containing the polycarbonate decomposition solution and the aromatic monoalcohol to obtain a solution containing bisphenol and the aromatic monoalcohol Step C2: The bisphenol obtained in Step B2 and a step of recovering bisphenol from a solution containing an aromatic monoalcohol

The process A of the bisphenol manufacturing method (2) is the same as the process A of the bisphenol manufacturing method (1).

[Step B2]
In step B2, the dialkyl carbonate and the aliphatic monoalcohol 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 step B2 after neutralization and washing, as in step B1 of the method for producing bisphenol (1). Step B2 is carried out using, for example, a mixed liquid obtained by mixing the polycarbonate decomposition liquid obtained in Step A and an aromatic monoalcohol. The polycarbonate decomposition solution may be neutralized or washed, mixed with an aromatic monoalcohol, and subjected to step B2.

[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 manufacturing plant that manufactures bisphenol A from acetone and phenol, the recycling process of the mother liquor (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.

Of 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 bisphenol-alkyl carbonate condensate>
In the present invention, polycarbonate resins are selected from the group consisting of dialkyl carbonates, aliphatic monoalcohols, alkali metal hydroxides, alkali metal carbonates, alkali metal alkoxides, alkali metal oxides, chain alkylamines and pyridine. A method for producing a bisphenol-alkyl carbonate condensate represented by the following formula (III), which is decomposed in the presence of any catalyst (hereinafter sometimes referred to as the “method for producing the condensate of the present invention”). It is a thing.

In formula (III), R is a methyl group, an ethyl group, or a butyl group.

In the method for producing the condensate of the present invention, the polycarbonate resin is a dialkyl carbonate, an aliphatic monoalcohol, an alkali metal hydroxide, an alkali metal carbonate, an alkali metal alkoxide, an alkali metal oxide, a chain alkylamine and pyridine. Decompose in the presence of any catalyst selected from the group consisting of

The types and amounts of the polycarbonate resin, dialkyl carbonate, aliphatic monoalcohol, and catalyst used in the method for producing a condensate of the present invention, the reaction temperature, the reaction time, etc. are the same as in the method for producing bisphenol of the present invention, and are suitable. Aspects are also the same. Further, similarly to the method for producing bisphenol of the present invention, the method for producing a condensate of the present invention comprises decomposing a polycarbonate resin in a slurry-like reaction liquid containing a polycarbonate resin, a dialkyl carbonate, an aliphatic monoalcohol and a catalyst. is preferred.

As described above, in the method for producing bisphenol of the present invention, the amount of aliphatic monoalcohol and the reaction time can be adjusted to produce a bisphenol-alkyl carbonate condensate as a by-product. By recovering this bisphenol-alkyl carbonate condensate, a bisphenol-alkyl carbonate condensate can be obtained. Recovery of the bisphenol-alkyl carbonate condensate is as described above.

In order to produce a bisphenol-alkyl carbonate condensate more efficiently, the molar ratio of the aliphatic monoalcohol used to 1 mol of the repeating unit of the polycarbonate resin used is preferably less than 2.0 and 1.95 or less. , 1.9 or less, 1.85 or less, or 1.8 or less.

A bisphenol-alkyl carbonate condensate can also be obtained by shortening the reaction time.

Since the alkyl carbonate group can be used as a protective group in the bisphenol-alkyl carbonate condensate, different functional groups can be selectively introduced into the two hydroxyl groups of bisphenol, leading to new products. .

<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 "recycled polycarbonate of the present invention"), in which a recycled polycarbonate resin is produced using a bisphenol raw material containing bisphenol (recycled bisphenol) obtained by the method for producing bisphenol of the present invention. It may be described as "resin manufacturing method"). The method for producing recycled polycarbonate resin of the present invention utilizes a chemical recycling method for producing polycarbonate resin 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 polycarbonate resins, 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.

Recycled bisphenol may be used as the entire bisphenol raw material, or may be mixed with general bisphenol that is not recycled bisphenol and used as part of the bisphenol raw material. 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 raw material for 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 excess 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 used is usually 1.001 mol or more, preferably 1.002 mol or more, and usually 1.3 mol or less, preferably 1.0 mol or more. 2 mol or less.

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 through a 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, it is easy to obtain the polymerization activity necessary for producing a recycled polycarbonate resin having a desired molecular weight, 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 the raw material mixing tank are usually stirred uniformly and then supplied to the polymerization tank where the catalyst is added to produce the 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 obtained recycled polycarbonate resin and composition 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.

The term "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.

The methods for manufacturing epoxy resin using the one-step method, the oxidation method, and the two-step method will be 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, a polyhydroxy compound other than the regenerated bisphenol (hereinafter sometimes referred to as "another polyhydroxy compound") may be used in combination with the regenerated bisphenol. 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, "other polyhydric hydroxy compounds" is a general term for dihydric or higher phenol compounds and dihydric or higher alcohol compounds, 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.

For the reaction, the polyvalent 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 reduced pressure, and the reaction temperature is preferably 20-200°C, more preferably 40-150°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 removed by filtration 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, an epoxy resin with a reduced total chlorine content can be produced 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.

Examples of aprotic polar solvents include 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 the alkali, a 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 20-200°C, more preferably 40-150°C, and the reaction time is preferably 0.1-24 hours, more preferably 0.5-10 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, the recycled bisphenol may be produced in combination with a polyhydric hydroxy compound other than the recycled 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 that is a combination of epoxy resin produced using recycled bisphenol and other epoxy resins that are 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 that is a combination of an epoxy resin produced using recycled bisphenol and other epoxy resins that are 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 method (ii) and method (iii) can be obtained by a one-step epoxy resin production method or an oxidation method. Also, the epoxy resin obtained by method (i) may be used. 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. is preferred. 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 raw 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. is 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 blending ratio.

The amount of the phenol-based curing agent is preferably 0.1 to 1000 parts by mass, more preferably 500 parts by mass or less with respect to 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 amine-based curing agents listed above may be used alone, or two or more of them may be used in any combination and in any 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]
Examples of the acid anhydride curing agent include acid anhydrides and modified acid anhydrides.

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-mentioned 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 acid anhydride-based curing agents listed above may be used alone or in combination of two or more in any combination and 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 total 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 include organic phosphines, phosphorous compounds such as phosphonium salts, tetraphenyl boron salts, organic acid dihydrazides, boron halide 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 a range 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 to be blended 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 may be used in any combination and ratio.

When a coupling agent is used in the epoxy resin composition, the compounding amount is preferably 0.001 to 10.0 parts by mass with respect to 100 parts by mass 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 paints such as electrodeposition paints for automobiles, heavy-duty anti-corrosion paints for ships and bridges, and paints for the inner surface of beverage cans; Suitable for any application such as seismic reinforcement of bridges, reinforcement of concrete, flooring of buildings, lining of water supply facilities, drainage/permeable pavement, 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.

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 it does not exceed the gist thereof.

[Raw materials and reagents]
Polycarbonate resin "NOVAREX (registered trademark) M7027BF" manufactured by Mitsubishi Chemical Engineering Plastics Co., Ltd. was used as polycarbonate resin (PC).
Methanol, dimethyl carbonate, ethanol, diethyl carbonate, butanol, triethylamine, sodium phenoxide, sodium hydroxide, potassium hydroxide, acetonitrile, and cesium carbonate were reagents supplied by Fujifilm Wako Pure Chemical Industries, Ltd.
1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) was a reagent from Tokyo Chemical Industry Co., Ltd.
Merck Co., Ltd. reagent was used for dibutyl carbonate.
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 jacket-type separable flask equipped with a Dimroth condenser, a stirring blade, and a thermometer, 52 g of methanol (52 g/32 g/mol = 1.6 mol, methanol/PC repeating unit (molar ratio) = 1.6 mol) was placed in a nitrogen atmosphere. 6 mol/0.31 mol=5.2), 120 g of dimethyl carbonate (120 g/90 g/mol=1.3 mol, dimethyl carbonate/PC repeating unit (molar ratio)=1.3 mol/0.31 mol= 4.2), and 1.1 g of sodium hydroxide (0.03 mol, sodium hydroxide/PC repeating unit (molar ratio) = 0.03 mol ÷ 0.31 mol = 0.10), 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 52 g + 120 g + 1.1 g + 80 g = 253 g). .1g).
After that, the jacket temperature was raised to 70°C. Undissolved polycarbonate resin was found in the reaction liquid when the temperature reached 70° C. (it was in the form of a slurry). The mixture was reacted for 3 hours while maintaining the jacket temperature at 70° 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 18.5% by mass (18.5/100 x 253.1 g/228 g/mol/0.31 mol x 100 = 66 mol%).

[Example 2]
In a jacket-type separable flask equipped with a Dimroth condenser, a stirring blade, and a thermometer, 52 g of methanol (1.6 mol, methanol/PC repeating unit (molar ratio) = 5.2) and 120 g of dimethyl carbonate were placed under a nitrogen atmosphere. (1.3 mol, dimethyl carbonate/PC repeating unit (molar ratio) = 4.2), and 1.1 g of potassium hydroxide (0.02 mol, potassium hydroxide/PC repeating unit (molar ratio) = 0 .02 mol ÷ 0.31 mol = 0.06) was added, and then 80 g of polycarbonate resin (number of moles of repeating unit = 0.31 mol) was added at room temperature (liquid volume was 52 g + 120 g + 1.1 g + 80 g = 253.1 g). .
After that, the jacket temperature was raised to 70°C. Undissolved polycarbonate resin was found in the reaction liquid when the temperature reached 70° C. (it was in the form of a slurry). The mixture was reacted for 3 hours while maintaining the jacket temperature at 65° C. to obtain a uniform reaction solution.
A portion of the resulting reaction solution was confirmed for composition by high-performance liquid chromatography, and bisphenol A was found to be 23.2% by mass (23.2/100 x 253.1 g/228 g/mol/0.31 mol x 100 = 83 mol%).

[Example 3]
In a jacket-type separable flask equipped with a Dimroth condenser, a stirring blade, and a thermometer, 80 g of methanol (80 g/32 g/mol = 2.5 mol, methanol/PC repeating unit (molar ratio) = 2.5 mol) was added under a nitrogen atmosphere. 5 mol/0.31 mol=8.1), 120 g of dimethyl carbonate (1.3 mol, dimethyl carbonate/PC repeating unit (molar ratio)=4.2), and 20 g of triethylamine (0.20 mol, triethylamine/ PC repeating unit (molar ratio) = 0.20 mol ÷ 0.31 mol = 0.65), then 80 g of polycarbonate resin (moles of repeating unit = 80 g ÷ 254 g / mol = 0.31 mol). It was added at room temperature (liquid volume: 80 g + 120 g + 20 g + 80 g = 300 g).
After that, the jacket temperature was raised to 70°C. Undissolved polycarbonate resin was found in the reaction liquid when the temperature reached 70° C. (it was in the form of a slurry). The mixture was reacted for 3 hours while maintaining the jacket temperature at 65° C. to obtain a uniform reaction solution.
When the composition of a part of the obtained reaction solution was confirmed by high-performance liquid chromatography, bisphenol A was found to be 19.5% by mass (19.5/100 x 300 g/228 g/mol/0.31 mol x 100 = 83 mol %).

[Example 4]
In a jacket-type separable flask equipped with a Dimroth condenser, a stirring blade, and a thermometer, 52 g of methanol (1.6 mol, methanol/PC repeating unit (molar ratio) = 5.2) and 120 g of dimethyl carbonate were placed under a nitrogen atmosphere. (1.3 mol, dimethyl carbonate/PC repeating unit (molar ratio) = 4.2), and 1.1 g of potassium carbonate (0.01 mol, potassium carbonate/PC repeating unit (molar ratio) = 0.01 mol÷0.31 mol=0.03), and then 80 g of polycarbonate resin (number of moles of repeating unit=0.31 mol) was added at room temperature (liquid volume: 52 g+120 g+1.1 g+80 g=253.1 g).
After that, the jacket temperature was raised to 70°C. Undissolved polycarbonate resin was found in the reaction liquid when the temperature reached 70° C. (it was in the form of a slurry). The mixture was reacted for 3 hours while maintaining the jacket temperature at 70° C. to obtain a uniform reaction solution.
When the composition of a portion of the obtained reaction solution was confirmed by high-performance liquid chromatography, bisphenol A was found to be 24.1 mass% (24.1/100 x 253.1 g/228 g/mol/0.31 mol x 100 = 86 mol%).

[Comparative Example 1]
In a jacket-type separable flask equipped with a Dimroth condenser, a stirring blade, and a thermometer, 80 g of a polycarbonate resin (the number of moles of repeating units = 0.31 mol) and 201 g of methanol (201 g/32 g/mol = 6.0 g) were placed under a nitrogen atmosphere. 28 mol, methanol/PC repeating unit (molar ratio)=6.28 mol/0.31 mol=20.25), and 15 g of triethylamine were added at room temperature.
Next, an attempt was made to raise the internal temperature to 85°C, but methanol refluxed at around 64°C, so the reaction was continued while maintaining the reflux. After reacting for 4 hours, the polycarbonate resin was found as a solid content in the reaction liquid, confirming that decomposition had not progressed.

Table 1 summarizes the reaction yields of the catalyst, solvent, and bisphenol in Examples 1 to 4 and Comparative Example 1.

[Example 5]
(i) Production of bisphenol A In a jacket-type separable flask equipped with a Dimroth condenser, a stirring blade, and a thermometer, 125 g of methanol (125 g/32 g/mol = 3.9 mol, methanol/PC repeating unit) was placed under a nitrogen atmosphere. (molar ratio) = 3.9 mol / 0.79 mol = 4.9), 300 g of dimethyl carbonate (300 g / 90 g / mol = 3.3 mol, dimethyl carbonate / PC repeating unit (molar ratio) = 3.3 mol ÷ 0.79 mol = 4.2), and after adding 3 g of potassium hydroxide, 200 g of polycarbonate resin (number of moles of repeating unit = 200 g ÷ 254 g / mol = 0.79 mol) was added at room temperature ( The amount of liquid is 125 g + 300 g + 3 g + 200 g = 628 g).
After that, the jacket temperature was raised to 70°C. Undissolved polycarbonate resin was found in the reaction liquid when the temperature reached 70° C. (it was in the form of a slurry). The mixture was reacted for 3 hours while maintaining the jacket temperature at 70° C. to obtain a uniform reaction solution.
When the composition of a part of the obtained reaction solution was confirmed by high performance liquid chromatography, bisphenol A was found to be 24.3% by mass (24.3/100 x 628 g/228 g/mol/0.79 mol x 100 = 85 mol %).

Dilute sulfuric acid was added to the resulting reaction solution until the pH of the aqueous phase reached 6. The precipitated potassium sulfate was filtered off by filtration under reduced pressure to obtain a uniform extract.

The extracted liquid 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 (760 Torr) to 120 Torr, the internal temperature was raised from room temperature to 80° C. while observing the amount of distillation, and 392 g of a fraction was withdrawn to obtain a still residue.

280 g of toluene was added to the obtained still residue to make 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 centrifuge to obtain a crude cake.

The whole amount of the obtained cake was supplied to a jacket-type separable flask equipped with a Dimroth condenser, a stirring blade, and a thermometer under a nitrogen atmosphere. After that, 10 g of dimethyl carbonate and 280 g of toluene were supplied. 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 15 Torr for 3 hours to obtain 121 g of a solid.

When the obtained solid was confirmed by high performance liquid chromatography, it was found to be bisphenol A with a purity of 99.9%. The melt color of the obtained bisphenol A was APHA11.

(ii) Production of recycled polycarbonate resin 100.00 g (0.44 mol) of bisphenol A obtained in (i) above and diphenyl carbonate were placed in a 150 mL glass reactor equipped with a stirrer and a distillation tube. 96.30 g (0.45 mol) and 160 μL of an aqueous solution of 400 ppm by mass of cesium carbonate were 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 200° 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. After that, the external temperature of the reaction vessel was raised to 250° 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 temperature outside the reaction vessel was raised to 290° C., the absolute pressure in the reaction vessel 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 (post-stage polymerization time) was 140 minutes.
Next, the pressure in the reactor was restored to 101.3 kPa in terms of absolute pressure with nitrogen, and then the pressure was increased to 0.2 MPa in terms of gauge pressure, and the polycarbonate resin was discharged from the bottom of the reactor in the form of strands to obtain a polycarbonate resin in strands. .
After that, the strand was pelletized using a rotary cutter to obtain a polycarbonate resin in the form of pellets.
The resulting polycarbonate resin had a viscosity-average molecular weight (Mv) of 20,900 and a pellet YI of 8.4.

[Comparative Example 2]
In the same manner as in Example 5, except that 3 g of 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) was added instead of 3 g of potassium hydroxide. carried out.
A part of the obtained reaction solution was checked for composition by high-performance liquid chromatography, and bisphenol A was found to be 24.1% by mass (24.1/100 x 628 g/228 g/mol/0.79 mol x 100 = 84 mol %).
120 g of a solid was obtained, and the resulting solid was confirmed by high performance liquid chromatography to be bisphenol A with a purity of 99.9%. The melt color of the obtained bisphenol A was APHA89.
Pellets YI of the obtained polycarbonate resin was 15.

In Example 5 and Comparative Example 2, the type of catalyst, the production rate of bisphenol A (BPA), the melt color of the obtained bisphenol A (BPA), and the obtained polycarbonate (PC) resin pellets YI are shown in Table 2. summarized. From Table 2, it can be seen that the melt color of the bisphenol A obtained by using potassium hydroxide is good, and the pellets YI of the obtained polycarbonate resin are also good.

In addition, the method for producing bisphenol of the present invention can use a general-purpose catalyst, and the catalyst cost is low. For example, 500 g of sodium hydroxide is 1,250 yen, 500 g of potassium hydroxide is 1,400 yen, 500 mL of triethylamine is 1,450 yen, and 100 g of potassium carbonate is 2,200 yen. . On the other hand, 5 g of TBD costs 16,300 yen, and when TBD is used, the cost of the catalyst becomes high in order to obtain the same production rate of bisphenol A.

[Example 6]
In a jacket-type separable flask equipped with a Dimroth condenser, a stirring blade, and a thermometer, 52 g of ethanol (52 g/46 g/mol=1.1 mol, ethanol/PC repeating unit (molar ratio)=1. 1 mol/0.31 mol=3.5), 120 g of diethyl carbonate (120 g/118 g/mol=1.0 mol, diethyl carbonate/PC repeating unit (molar ratio)=1.0 mol/0.31 mol= 3.2), and 1.1 g of potassium hydroxide (0.02 mol, potassium hydroxide/PC repeating unit (molar ratio) = 0.02 mol ÷ 0.31 mol = 0.06), 80 g of polycarbonate resin (number of moles of repeating unit=0.31 mol) was added at room temperature (liquid amount: 52 g+120 g+1.1 g+80 g=253.1 g).
After that, the jacket temperature was raised to 70°C. Undissolved polycarbonate resin was found in the reaction liquid when the temperature reached 70° C. (it was in the form of a slurry). The mixture was reacted for 3 hours while maintaining the jacket temperature at 70° C. to obtain a uniform reaction solution.
When the composition of a portion of the obtained reaction solution was confirmed by high-performance liquid chromatography, bisphenol A was found to be 22.5% by mass (22.5/100 x 253.1 g/228 g/mol/0.31 mol x 100 = 81 mol%).

[Example 7]
In a jacket-type separable flask equipped with a Dimroth condenser, a stirring blade, and a thermometer, 10 g of butanol (10 g ÷ 74 g / mol = 135 mmol, butanol / PC repeating unit (molar ratio) = 135 mmol ÷ 39 under a nitrogen atmosphere .4 mmol = 3.4), 30 g of dibutyl carbonate (30 g ÷ 174 g/mol = 172 mmol, dibutyl carbonate/PC repeating unit (molar ratio) = 172 mmol ÷ 39.4 mmol = 4.4), and hydroxylation After adding 0.1 g of potassium (1.8 millimoles, potassium hydroxide/PC repeating unit (molar ratio) = 1.8 millimoles ÷ 39.4 millimoles = 0.05), 10 g of polycarbonate resin (repeating unit moles number = 10 g/254 g/mol = 39.4 mol) was added at room temperature (liquid volume was 10 g + 30 g + 0.1 g + 10 g = 50.1 g).
After that, the jacket temperature was raised to 70°C. Undissolved polycarbonate resin was found in the reaction liquid when the temperature reached 70° C. (it was in the form of a slurry). The mixture was reacted for 3 hours while maintaining the jacket temperature at 70° C. to obtain a uniform reaction solution.
A portion of the resulting reaction solution was confirmed for composition by high-performance liquid chromatography, and bisphenol A was found to be 7.1% by mass (7.1/100 x 50.1 g/228 g/mol/0.04 mol x 100 = 39 mol%).

[Example 8]
In a jacket-type separable flask equipped with a Dimroth condenser, a stirring blade, and a thermometer, 16 g of methanol (16 g/32 g/mol = 0.5 mol, methanol/PC repeating unit (molar ratio) = 0.5 mol) was added under a nitrogen atmosphere. 5 mol/0.31 mol=1.6), 160 g of dimethyl carbonate (160 g/90 g/mol=1.8 mol, dimethyl carbonate/PC repeating unit (molar ratio)=1.8 mol/0.31 mol= 5.8) and 1.6 g of potassium hydroxide were added, and then 80 g of polycarbonate resin (number of moles of repeating unit = 0.31 mol) was added at room temperature (liquid volume was 16 g + 160 g + 1.6 g + 80 g = 257.6 g). .
After that, the jacket temperature was raised to 65°C. Undissolved polycarbonate resin was found in the reaction liquid when the temperature reached 65° C. (it was in the form of a slurry). The mixture was reacted for 3 hours while maintaining the jacket temperature at 65° C. to obtain a uniform reaction solution.
After neutralizing the obtained reaction solution with dilute sulfuric acid, potassium sulfate was filtered to obtain a filtrate. The filtrate was placed in an eggplant flask and dried under full vacuum using an evaporator equipped with an oil bath to obtain 57 g of a solid. A portion of the obtained solid was analyzed by high-performance liquid chromatography to find 87.3% by mass of bisphenol A and 12.7% by mass of bisphenol-methyl carbonate condensate.

[Example 9A]
46 g of bisphenol A obtained in Example 5 (BPA purity of 99%), 259 g of epichlorohydrin, 100 g of isopropanol, and 36 g of water were placed in a 1-liter four-necked flask equipped with a thermometer, a stirrer, and a cooling tube, and the temperature was raised to 40°C. After the mixture was heated and uniformly dissolved, 38 g of a 48.5% by weight sodium hydroxide aqueous solution was added dropwise over 90 minutes. Simultaneously with the dropping, the temperature was raised from 40° C. to 65° C. over 90 minutes. Thereafter, the reaction solution was held at 65°C for 30 minutes to complete the reaction, transferred to a 1 L separating funnel, added with 69 g of water at 65°C, and allowed to stand at 65°C for 1 hour. After standing, the water layer was extracted from the separated oil layer and water layer, and by-product salts and excess sodium hydroxide were removed. After that, epichlorohydrin was completely removed under reduced pressure at 150°C.
After that, 102 g of methyl isobutyl ketone was charged, heated to 65° C. and dissolved uniformly, then 1.4 g of a 48.5% by weight sodium hydroxide aqueous solution was charged, reacted for 60 minutes, and then 57 g of methyl isobutyl ketone. and washed with 200 g of water four times. Thereafter, methyl isobutyl ketone was completely removed under reduced pressure at 150° C. to obtain a regenerated epoxy resin of Example 9A.
The epoxy equivalent of the obtained epoxy resin was measured according to JISK7236 (2009) and found to be 179 g/equivalent.

[Reference Example 1A]
46 g of bisphenol A (Mitsubishi Chemical Co., Ltd.), 259 g of epichlorohydrin, 100 g of isopropanol, and 36 g of water were charged in a 1-liter four-necked flask equipped with a thermometer, a stirrer, and a cooling tube, and the temperature was raised to 40° C. and the temperature was uniform. 38 g of a 48.5% by weight sodium hydroxide aqueous solution was added dropwise over 90 minutes. Simultaneously with the dropping, the temperature was raised from 40° C. to 65° C. over 90 minutes. After that, the reaction solution was kept at 65°C for 30 minutes to complete the reaction, transferred to a 1 L separating funnel, added with 69 g of water at 65°C, and allowed to stand at 65°C for 1 hour. After standing, the water layer was extracted from the separated oil layer and water layer, and by-product salts and excess sodium hydroxide were removed. After that, epichlorohydrin was completely removed under reduced pressure at 150°C.
After that, 102 g of methyl isobutyl ketone was charged, heated to 65° C. and dissolved uniformly, then 1.4 g of a 48.5% by weight sodium hydroxide aqueous solution was charged, reacted for 60 minutes, and then 57 g of methyl isobutyl ketone. and washed with 200 g of water four times. Thereafter, methyl isobutyl ketone was completely removed under reduced pressure at 150° C. to obtain an epoxy resin of Reference Example 1A.
The epoxy equivalent of the obtained epoxy resin was measured according to JISK7236 (2009) and found to be 179 g/equivalent.

[Example 9B and Reference Example 1B]
(Epoxy resin composition)
In the ratio shown in Table 2, the epoxy resin of Example 9A or Reference Example 1A, a curing agent (trade name Rikacid MH-700 manufactured by Shin Nippon Rika Co., Ltd.) and a curing catalyst (trade name Cure Sol 2E4MZ manufactured by Shikoku Kasei Kogyo Co., Ltd.) The ingredients were weighed, stirred and mixed at room temperature until uniform, to obtain an epoxy resin composition.

(Epoxy resin cured product)
Two glass plates to which the release PET film was adhered were prepared, and the distance between the two glass plates was adjusted to 3 mm with the release PET film on the inner side to prepare a mold. An epoxy resin composition was cast into this mold and heated at 100° C. for 3 hours and then at 140° C. for 3 hours to obtain a cured epoxy resin. The resulting cured product was cut into a length of 5 cm, a width of 1 cm and a thickness of 3 mm to obtain a test piece.

(Evaluation of physical properties of cured product)
The test piece was heated from 30° C. to 280° C. at a rate of 5° C./min in a three-point bending mode using a thermomechanical analyzer (DMA: EXSTAR6100 manufactured by Seiko Instruments Inc.), and E′ at 250° C. was measured. , 250° C. elastic modulus.

[Evaluation of results]
From Table 3, it can be seen that the epoxy resin cured product of Example 9B has a higher elastic modulus at 250° C. than the epoxy resin cured product of Reference Example 1B, and is excellent in heat deformation resistance.

[Example 10]
(First decomposition step)
In a jacket-type separable flask equipped with a Dimroth condenser, a stirring blade, and a thermometer, 52 g of methanol (1.6 mol, methanol/PC repeating unit (molar ratio) = 5.2) and 120 g of dimethyl carbonate were placed under a nitrogen atmosphere. (1.3 mol, dimethyl carbonate/PC repeating unit (molar ratio) = 4.2), and 1.1 g of sodium hydroxide (0.03 mol, sodium hydroxide/PC repeating unit (molar ratio) = 0 .10) was added, 80 g of polycarbonate resin (number of moles of repeating unit=0.31 mol) was added at room temperature (liquid amount: 52 g+120 g+1.1 g+80 g=253.1 g).

After that, the jacket temperature was raised to 70°C. Undissolved polycarbonate resin was found in the reaction liquid when the temperature reached 70° C. (it was in the form of a slurry). The reaction was continued for 3 hours while maintaining the jacket temperature at 70° C. to obtain a first decomposition liquid (uniform reaction liquid).

When the composition of a part of the obtained first decomposition liquid was confirmed by high performance liquid chromatography, bisphenol A was found to be 18.5% by mass (18.5/100 x 253.1 g/228 g/mol/0.31 mol×100=66 mol %). Further, when the composition was confirmed by gas chromatography, it was 14.7% by mass of methanol and 55.2% by mass of dimethyl carbonate.

(Second decomposition step)
5.6 g (0.31 mol) of water was added to this first decomposition solution, and the mixture was stirred for 1 hour while maintaining the temperature at 70°C. After 1 hour, when the stirring was stopped and the mixture was allowed to stand still, it was confirmed that a white solid had precipitated on the wall of the separable flask.

The reaction solution was extracted and weighed to be 243.8 g. When the composition was confirmed by high-performance liquid chromatography, 25.7% by mass of bisphenol A (25.7/100 x 243.8 g/228 g/mol/0 .31 mol x 100 = 88.6 mol%).

Further, when the composition was confirmed by gas chromatography, methanol was 21.1% by mass, and the recovery rate for the methanol supplied to the reaction was 98.9% by mass (21.1/100 x 243.8/52 g x 100 = 98.9% by mass). In addition, dimethyl carbonate is 49.0% by mass, and the recovery rate for the dimethyl carbonate supplied to the reaction is 99.5% by mass (49.0/100 x 243.8/120g x 100 = 99.5% by mass). there were.

[Example 11]
(First decomposition step)
A first decomposition step was performed in the same manner as in Example 10 to obtain a first decomposition solution (uniform reaction solution). When the composition of a part of the obtained first decomposition liquid was confirmed by high performance liquid chromatography, bisphenol A was found to be 18.4% by mass (18.4/100 x 253.1 g/228 g/mol/0.31 mol×100=66 mol %). Further, when the composition was confirmed by gas chromatography, methanol was 14.6% by mass and dimethyl carbonate was 55.3% by mass.

(Second decomposition step)
4.5 g (0.25 mol) of water was added to this first decomposition solution, and the mixture was stirred for 1 hour while maintaining the temperature at 70°C. After 1 hour, when the stirring was stopped and the mixture was allowed to stand still, it was confirmed that a white solid was deposited on the wall of the separable flask.

When the reaction liquid was extracted and weighed, it was 245.8 g. When the composition was confirmed by high-performance liquid chromatography, 24.5% by mass of bisphenol A (24.5/100 x 245.8 g/228 g/mol/0 .31 mol x 100 = 85.2 mol%).

Further, when the composition was confirmed by gas chromatography, methanol was 19.1% by mass, and the recovery rate for the methanol supplied to the reaction was 90.3% by mass (19.1/100 x 245.8/52 g x 100 = 90.3% by mass). In addition, dimethyl carbonate is 51.3% by mass, and the recovery rate for the dimethyl carbonate supplied to the reaction is 105.1% by mass (51.3/100 x 245.8/120g x 100 = 105.1% by mass). there were.

The obtained extracted liquid was dried using an evaporator equipped with an oil bath to obtain bisphenol. In addition, the distillate was 165 g, and when the composition was confirmed by gas chromatography, it was 28.4% by mass of methanol (28.4 ÷ 100 x 165 g = 46.9 g) and 70.4% by mass of dimethyl carbonate. (70.4/100 x 165g = 116.2g).

[Example 12]
(First decomposition step)
In a jacketed separable flask equipped with a Dimroth condenser, a stirring blade, and a thermometer, under a nitrogen atmosphere, 165 g of the distillate obtained in Example 11 (containing 46.9 g of methanol and 116.2 g of dimethyl carbonate), methanol 5 1 g (52 g (1.6 mol) combined with methanol in the distillate, methanol/PC repeating unit (molar ratio) = 1.6 mol/0.31 mol = 5.2), dimethyl carbonate 3. 8 g (120 g (1.3 mol) combined with dimethyl carbonate in the distillate, dimethyl carbonate/PC repeating unit (molar ratio) = 1.3 mol ÷ 0.31 mol = 4.2), and hydroxylation After adding 1.1 g of sodium (0.03 mol, sodium hydroxide/PC repeating unit (molar ratio) = 0.10), 80 g of polycarbonate resin (moles of repeating unit = 80 g/254 g/mol = 0.10) was added. 31 mol) was added at room temperature (liquid volume was 165 g + 5.1 g + 3.8 g + 1.1 g + 80 g = 255.0 g).

When the composition of a part of the obtained first decomposition liquid was confirmed by high-performance liquid chromatography, bisphenol A was found to be 18.4% by mass (18.4/100 x 255.0 g/228 g/mol/0.31 mol×100=66 mol %). Further, when the composition was confirmed by gas chromatography, it was 14.6% by mass of methanol and 54.8% by mass of dimethyl carbonate.

(Second decomposition step)
6.7 g (0.37 mol) of water was added to this first decomposition solution, and the mixture was stirred for 1 hour while maintaining the temperature at 70°C. After 1 hour, when the stirring was stopped and the mixture was allowed to stand still, it was confirmed that a white solid was deposited on the wall of the separable flask.

The reaction solution was extracted and weighed to find 243.6 g. When the composition was confirmed by high-performance liquid chromatography, 26.2% by mass of bisphenol A (26.2/100 x 243.6 g/228 g/mol/0 .31 mol x 100 = 90.3 mol%).

Also, when the composition was confirmed by gas chromatography, methanol was 23.1% by mass, and the recovery rate with respect to the methanol supplied to the reaction was 109.9% by mass (23.1/100 x 243.6/52 g x 100 = 108.2% by mass). In addition, dimethyl carbonate is 46.3% by mass, and the recovery rate for the dimethyl carbonate supplied to the reaction is 94.1% by mass (46.3/100 x 243.6/120g x 100 = 94.0% by mass). there were.

[Example 13]
(First decomposition step)
A first decomposition step was performed in the same manner as in Example 10 to obtain a first decomposition solution (uniform reaction solution). When the composition of a part of the obtained first decomposition liquid was confirmed by high performance liquid chromatography, bisphenol A was found to be 18.5% by mass (18.5/100 x 253.1 g/228 g/mol/0.31 mol×100=66 mol %). Further, when the composition was confirmed by gas chromatography, it was 14.7% by mass of methanol and 55.2% by mass of dimethyl carbonate.

(Second decomposition step)
2.2 g (0.12 mol) of water was added to this first decomposition solution, and the mixture was stirred for 1 hour while maintaining the temperature at 70°C. After 1 hour, when the stirring was stopped and the mixture was allowed to stand still, it was confirmed that a white solid was deposited on the wall of the separable flask.

The reaction liquid was extracted and weighed to be 248.8 g. When the composition was confirmed by high-performance liquid chromatography, 22.6% by mass of bisphenol A (22.6/100 x 248.8 g/228 g/mol/0 .31 mol x 100 = 79.6 mol%).

Further, when the composition was confirmed by gas chromatography, methanol was 15.9% by mass, and the recovery rate for the methanol supplied to the reaction was 77.0% by mass (15.9/100 x 248.8/52 g x 100 = 76.1% by mass). In addition, dimethyl carbonate was 54.8% by mass, and the recovery rate with respect to the dimethyl carbonate supplied to the reaction was 113.6% by mass (54.8/100 x 248.8/120g x 100 = 113.6% by mass). there were.

[Example 14]
(First decomposition step)
A first decomposition step was performed in the same manner as in Example 10 to obtain a first decomposition solution (uniform reaction solution). When the composition of a part of the obtained first decomposition liquid was confirmed by high-performance liquid chromatography, bisphenol A was found to be 18.5% by mass (18.5/100 x 253.1 g/228 g/mol/0.31 mol×100=66 mol %). Further, when the composition was confirmed by gas chromatography, methanol was 14.7% by mass and dimethyl carbonate was 55.2% by mass.

(Second decomposition step)
11.2 g (0.62 mol) of water was added to this first decomposition solution, and the mixture was stirred for 1 hour while maintaining the temperature at 70°C. After 1 hour, when the stirring was stopped and the mixture was allowed to stand still, it was confirmed that a white solid was deposited on the wall of the separable flask.

The reaction solution was extracted and weighed to find 235.4 g. When the composition was confirmed by high-performance liquid chromatography, 27.6% by mass of bisphenol A (27.6/100 x 235.4 g/228 g/mol/0 .31 mol x 100 = 91.9 mol%).

Further, when the composition was confirmed by gas chromatography, methanol was 30.6% by mass, and the recovery rate for the methanol supplied to the reaction was 138.5% by mass (30.6/100 x 235.4/52 g x 100 = 138.5% by mass). In addition, dimethyl carbonate is 38.6% by mass, and the recovery rate for the dimethyl carbonate supplied to the reaction is 75.7% by mass (38.6/100 x 235.4/120g x 100 = 75.7% by mass). there were.

The results of Examples 10-14 are summarized in Table 4. From Table 4, it can be seen that by adding water during the reaction to hydrolyze the dialkyl carbonate, the decomposition reaction of bisphenol A can be accelerated and the yield of bisphenol A can be further improved. In addition, by adjusting the amount of water to be added within a certain range, the aliphatic monoalcohol is regenerated from the dialkyl carbonate produced by the alcoholysis of the polycarbonate resin, and the ratio of the dialkyl carbonate and the aliphatic monoalcohol in the recovered mixture is changed to , it is possible to maintain a ratio (80% by mass to 120% by mass) that is easy to reuse in the first decomposition step.

[Example 15]
In a jacket-type separable flask equipped with a Dimroth condenser, a stirring blade, and a thermometer, 50 g of methanol (50 g/32 g/mol = 1.6 mol, methanol/PC repeating unit (molar ratio) = 1.6 mol) was placed in a nitrogen atmosphere. 6 mol ÷ 0.31 mol = 5.2), 120 g of dimethyl carbonate (1.3 mol, dimethyl carbonate/PC repeating unit (molar ratio) = 4.2), and 1.2 g of potassium hydroxide (0.02 mol, potassium hydroxide / PC repeating unit (molar ratio) = 0.02 mol ÷ 0.31 mol = 0.1), and then 80 g of polycarbonate resin (moles of repeating unit = 0.31 mol). It was added at room temperature (liquid volume: 50 g + 120 g + 1.2 g + 80 g = 251.2 g).
After that, the jacket temperature was raised to 70°C. Undissolved polycarbonate resin was found in the reaction liquid when the temperature reached 70° C. (it was in the form of a slurry). The theoretical slurry concentration at the start of decomposition was 0.32 (mass of polycarbonate resin: 80 g/mass of decomposed liquid: 251.2 g = 0.32).
The mixture was reacted for 3 hours while maintaining the jacket temperature at 70° C. to obtain a uniform reaction solution.
When the composition of a part of the obtained reaction solution was confirmed by high-performance liquid chromatography, bisphenol A was found to be 24.5% by mass (24.5/100 x 251.2 g/228 g/mol/0.31 mol x 100 = 87 mol%).

[Example 16]
The polycarbonate resin was decomposed under the same conditions as in Example 15, except that the supply amount of dimethyl carbonate was changed from 120 g to 105 g (1.2 mol, dimethyl carbonate/PC repeating unit (molar ratio) = 3.9). . The theoretical slurry concentration at the start of decomposition was 0.34 (mass of polycarbonate resin: 80 g/mass of decomposed liquid: 236.2 g = 0.34).
The reaction solution was homogeneous 3 hours after the start of decomposition. When the composition of a part of this reaction liquid was confirmed by high-performance liquid chromatography, bisphenol A was found to be 26.7% by mass (26.7/100 x 236.2 g/228 g/mol/0.31 mol x 100 = 89 mol %).

[Example 17]
The polycarbonate resin was decomposed under the same conditions as in Example 15, except that the supply amount of dimethyl carbonate was changed from 120 g to 94 g (1.0 mol, dimethyl carbonate/PC repeating unit (molar ratio) = 3.2). . The theoretical slurry concentration at the start of decomposition was 0.36 (mass of polycarbonate resin: 80 g/mass of decomposed liquid: 225.2 g = 0.36).
The reaction solution was homogeneous 3 hours after the start of decomposition. When the composition of a part of this reaction liquid was confirmed by high-performance liquid chromatography, bisphenol A was found to be 28.0% by mass (28.0 ÷ 100 x 225.2 g ÷ 228 g/mol ÷ 0.31 mol x 100 = 89 mol %).

[Example 18]
The polycarbonate resin was decomposed under the same conditions as in Example 15, except that the supply amount of dimethyl carbonate was changed from 120 g to 74 g (0.8 mol, dimethyl carbonate/PC repeating unit (molar ratio) = 2.6). . The theoretical slurry concentration at the start of decomposition was 0.39 (mass of polycarbonate resin: 80 g/mass of decomposed liquid: 205.2 g = 0.39).
The reaction solution was homogeneous 3 hours after the start of decomposition. When the composition of a part of this reaction liquid was confirmed by high-performance liquid chromatography, bisphenol A was found to be 28.4% by mass (28.4 ÷ 100 x 205.2 g ÷ 228 g/mol ÷ 0.31 mol x 100 = 82 mol %).

[Example 19]
The polycarbonate resin was decomposed under the same conditions as in Example 15, except that the supply amount of dimethyl carbonate was changed from 120 g to 52 g (0.6 mol, dimethyl carbonate/PC repeating unit (molar ratio) = 1.9). . The theoretical slurry concentration at the start of decomposition was 0.44 (mass of polycarbonate resin: 80 g/mass of decomposed liquid: 183.2 g = 0.44).
The reaction solution was homogeneous 3 hours after the start of decomposition. When the composition of a part of this reaction liquid was confirmed by high performance liquid chromatography, bisphenol A was 25.2% by mass (25.2 ÷ 100 x 183.2 g ÷ 228 g/mol ÷ 0.31 mol x 100 = 65 mol %).
The reaction was continued for an additional hour while maintaining the temperature at 70°C. Four hours after the start of decomposition, a portion of the reaction solution was analyzed for composition by high-performance liquid chromatography. .8 ÷ 100 x 183.2 g ÷ 228 g/mole ÷ 0.31 mol x 100 = 80 mol%).

[Comparative Example 3]
The polycarbonate resin was decomposed under the same conditions as in Example 15, except that the supply amount of dimethyl carbonate was changed from 120 g to 45 g (0.5 mol, dimethyl carbonate/PC repeating unit (molar ratio) = 1.6). .
Immediately after decomposition started, part of the polycarbonate resin deposited between the thermometer and the separable flask. This accumulated agglomerate of polycarbonate resin did not completely dissolve even 3 hours after decomposition began. The theoretical slurry concentration at the start of decomposition was 0.45 (mass of polycarbonate resin: 80 g/mass of decomposed liquid: 176.2 g = 0.45).

[Comparative Example 4]
The polycarbonate resin was decomposed under the same conditions as in Example 15, except that the supply amount of dimethyl carbonate was changed from 120 g to 30 g (0.3 mol, dimethyl carbonate/PC repeating unit (molar ratio) = 1.0). .
Immediately after the start of decomposition, the polycarbonate resin did not disperse and agglomerated, and the stirring impeller was overloaded, making it idling and making stirring impossible, so the decomposition reaction was stopped. The theoretical slurry concentration at the start of decomposition was 0.50 (mass of polycarbonate resin: 80 g/mass of decomposed liquid: 161.2 g = 0.50).

[Comparative Example 5]
The amount of dimethyl carbonate supplied was 120 g to 30 g (0.3 mol, repeating unit (molar ratio) of dimethyl carbonate/PC = 1.0), and the amount of methanol supplied was 50 g to 80 g (2.5 mol, of methanol/PC). The polycarbonate resin was decomposed under the same conditions as in Example 15, except that the repeating unit (molar ratio) was changed to 8.1).
The mixability of the polycarbonate resin was good, but much of the polycarbonate resin was still undissolved even after 3 hours from the start of decomposition. The reaction was continued while maintaining the temperature at 70° C. for another hour, but the polycarbonate resin was not completely dissolved. The theoretical slurry concentration at the start of decomposition was 0.42 (mass of polycarbonate resin: 80 g/mass of decomposed liquid: 191.2 g = 0.42).

The results of Examples 15-19 and Comparative Examples 3-5 are summarized in Table 5. From Table 5, it can be seen that the dissolution rate and decomposition rate of the polycarbonate resin can be maintained by supplying an appropriate amount of the dialkyl carbonate solvent to the repeating units of the polycarbonate resin to be decomposed. If the amount of dialkyl carbonate supplied is small with respect to the repeating units of the polycarbonate resin, the rate of dissolution of the polycarbonate resin will decrease, and the time required for decomposition of the polycarbonate resin will lengthen, which is inefficient.

According to the present invention, chemical recycling can be used to obtain useful compounds such as bisphenol from waste plastics. Furthermore, using these, polycarbonate resins and epoxy resins can be produced again, which is industrially useful.

Claims

A method for producing bisphenol, wherein the decomposition reaction of the polycarbonate resin is performed in a reaction solution containing a polycarbonate resin, a dialkyl carbonate, an aliphatic monoalcohol and a catalyst,
The molar ratio of the dialkyl carbonate used in the decomposition reaction to 1 mol of repeating units derived from bisphenol in the polycarbonate resin used in the decomposition reaction is 1.8 or more,
A method for producing bisphenol, wherein the catalyst is selected from the group consisting of alkali metal hydroxides, alkali metal carbonates, alkali metal alkoxides, alkali metal oxides, chain alkylamines and pyridine.
The method for producing bisphenol according to claim 1, wherein the reaction liquid is slurry.
The method for producing bisphenol according to claim 1 or 2, wherein the dialkyl carbonate contains a dialkyl carbonate not derived from the polycarbonate resin.
The method for producing bisphenol according to claim 1 or 2, wherein the reaction liquid is prepared by mixing the polycarbonate resin, the dialkyl carbonate, the aliphatic monoalcohol, and the catalyst.
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 1, wherein said alkali metal oxide is sodium oxide or potassium oxide.
The method for producing bisphenol according to claim 1 or 2, wherein the chain 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.
The method for producing bisphenol according to claim 1 or 2, wherein the dialkyl carbonate is dimethyl carbonate, diethyl carbonate or dibutyl carbonate.
The method for producing bisphenol according to claim 1 or 2, wherein the bisphenol is 2,2-bis(4-hydroxyphenyl)propane.
The method for producing bisphenol according to claim 1 or 2, wherein the aliphatic monoalcohol is methanol, ethanol or butanol.
3. The method for producing bisphenol according to claim 1 or 2, comprising the following step A, step B1 and step C1.
Step A: Step of decomposing the polycarbonate resin in the reaction solution containing the polycarbonate resin, the dialkyl carbonate, the aliphatic monoalcohol and the catalyst to obtain a non-slurry polycarbonate decomposition solution containing bisphenol Step B1: A step of concentrating the polycarbonate decomposition liquid obtained in the step A to obtain a concentrated liquid. Step C1: An aromatic hydrocarbon is supplied to the concentrated liquid obtained in the step B1 to crystallize, thereby precipitating bisphenol. a step of obtaining a slurry containing bisphenol and subjecting the obtained slurry to solid-liquid separation to obtain bisphenol
3. The method for producing bisphenol according to claim 1 or 2, comprising the following Step A, Step B2 and Step C2.
Step A: Step of decomposing the polycarbonate resin in the reaction solution containing the polycarbonate resin, the dialkyl carbonate, the aliphatic monoalcohol and the catalyst to obtain a non-slurry polycarbonate decomposition solution containing bisphenol Step B2: A step of removing the dialkyl carbonate and the aliphatic monoalcohol from the solution containing the polycarbonate decomposition solution and the aromatic monoalcohol obtained in step A to obtain a solution containing bisphenol and the aromatic monoalcohol Step C2: the above step Step of recovering bisphenol from the solution containing bisphenol and aromatic monoalcohol obtained in B2
a first decomposition step of decomposing the polycarbonate resin in the reaction solution containing the polycarbonate resin, the dialkyl carbonate, the aliphatic monoalcohol and the catalyst to obtain a first decomposition solution containing bisphenol;
a second decomposition step of hydrolyzing the dialkyl carbonate by mixing the first decomposition liquid and water to regenerate the aliphatic monoalcohol and decomposing the polycarbonate resin to produce bisphenol; have
2. The method for producing bisphenol according to claim 1, wherein said first decomposition step and said second decomposition step are continuously performed.
12. Water mixed with the first decomposition solution is 0.5 mol or more and 1.5 mol or less per 1 mol of repeating units derived from bisphenol in the polycarbonate resin used in the decomposition reaction. The method for producing bisphenol according to .
The aliphatic monoalcohol regenerated in the second decomposition step is separated from the bisphenol as a mixture with the dialkyl carbonate, and the mixture of the aliphatic monoalcohol and the dialkyl carbonate is reused in the first decomposition step. The method for producing bisphenol according to claim 12 or 13.
The method for producing bisphenol according to claim 12 or 13, wherein the reaction liquid is slurry and the first decomposition liquid is not slurry.
3. The method for producing bisphenol according to claim 1 or 2, wherein a bisphenol-alkyl carbonate condensate represented by the following formula (III), which is a by-product of decomposition of the polycarbonate resin, is further recovered.
In formula (III), R is a methyl group, an ethyl group or a butyl group.
The method for producing bisphenol according to claim 16, wherein in the formula (III), R is a methyl group.
A method for producing recycled polycarbonate resin, comprising obtaining bisphenol through the method for producing bisphenol according to claim 1 or 2, and then producing 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 claim 1 or 2, and then producing an epoxy resin using a polyhydric hydroxy compound raw material containing the bisphenol.
20. Production of an epoxy resin, comprising: obtaining an epoxy resin through the method for producing an epoxy resin according to claim 19; Method.
An epoxy resin is obtained through the method for producing an epoxy resin according to claim 19, an epoxy resin composition containing the epoxy resin and a curing agent is obtained, and the epoxy resin composition is cured to obtain a cured epoxy resin. , a method for producing a cured epoxy resin.
A method for producing a bisphenol-alkyl carbonate condensate represented by the following formula (III), wherein the polycarbonate resin is decomposed in a reaction solution containing a polycarbonate resin, a dialkyl carbonate, an aliphatic monoalcohol and a catalyst,
Production of bisphenol-alkyl carbonate condensate, wherein the catalyst is selected from the group consisting of alkali metal hydroxide, alkali metal carbonate, alkali metal alkoxide, alkali metal oxide, chain alkylamine and pyridine Method.
In formula (III), R is a methyl group, an ethyl group or a butyl group.