JP2024017471A - Method for producing metal phenoxide, method for producing epoxy resin, and method for producing cured epoxy resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for efficiently obtaining metal phenoxide from decomposition products of thermosetting resins, which contain a variety of substances in addition to the thermosetting resin, such as epoxy resin.

SOLUTION: A method for producing metal phenoxide includes following steps A-C. Step A: decomposing a thermosetting cured resin to produce a decomposition liquid A containing metal phenoxide. Step B: adding water to the decomposition liquid A obtained in the step A, to produce an oil-water two-phase liquid B. Step C: separating the oil-water two-phase liquid B obtained in the step B to oil and water, thereby recovering metal phenoxide.

SELECTED DRAWING: None

COPYRIGHT: (C)2024,JPO&INPIT

Description

The present invention relates to a method for producing a metal phenoxide, a method for producing an epoxy resin, and a method for producing a cured epoxy resin product.

By curing thermosetting resins such as epoxy resins under various formulations and curing conditions, cured products with generally excellent mechanical properties and heat resistance can be obtained. Therefore, thermosetting resins are used in a wide range of fields such as adhesives, paints, FRP, and electrical and electronic materials.

On the other hand, due to its excellent mechanical properties, it is difficult to process thermosetting resins after curing, and after the cured product is used for various purposes, it is difficult to extract only the thermosetting resin from the product for that purpose. It is difficult. In particular, it is difficult to physically remove the thermosetting resin from a cured product obtained by curing the thermosetting resin in contact with metals, inorganic fibers, and the like.

Under these circumstances, as a method for removing epoxy resin from a cured epoxy resin product, Cited Document 1 discloses a method of decomposing, dissolving, and recovering the cured epoxy resin product using an organic solvent and an alkali metal catalyst. Furthermore, a method has been proposed for producing an epoxy resin by reacting the obtained epoxy resin decomposition product with an epoxy resin.

JP 2017-019959 Publication

However, in the method disclosed in Patent Document 1, epoxy resin cannot be selectively recovered from epoxy resin decomposition products, and epoxy resin is produced by reacting with epoxy resin while containing various other products. are doing. Therefore, the epoxy equivalent of the obtained epoxy resin was very low, and it could not be said that the technique had a high yield (recovery rate) of epoxy resin.

An object of the present invention is to provide a method for efficiently obtaining metal phenoxide from a thermosetting resin decomposition product containing various products in addition to thermosetting resins such as epoxy resins.

The present inventors conducted studies to solve the above problems and discovered that a metal phenoxide can be obtained by adding water to a decomposed liquid of a thermosetting resin and separating oil and water. They confirmed that it was possible to synthesize epoxy resin again from the metal phenoxide obtained through this process, and completed the invention.

That is, the gist of the present invention may include the following [1] to [9].
[1] A method for producing metal phenoxide, including the following steps A to C.
Step A: Decompose the thermosetting resin cured product to obtain decomposed liquid A containing metal phenoxide Step B: Add water to decomposed liquid A obtained in step A to obtain oil-water two-phase liquid B Step C : Separating the oil-water two-phase liquid B obtained in step B to obtain metal phenoxide [2] The method for producing metal phenoxide according to [1], wherein the step C includes the following steps D to E. .
Step D: Separate the oil-water two-phase liquid B obtained in step B, and mix the obtained aqueous phase C and an organic solvent to obtain suspension D. Step E: The suspension obtained in step D. A step [3] of solid-liquid separation of the turbid liquid D to obtain metal phenoxide from the solid phase [3] The above step B is a decomposed liquid A obtained by solid-liquid separation of the decomposed liquid A obtained in the above step A to remove insoluble matter. The method for producing a metal phenoxide according to [1] or [2], wherein the oil-water two-phase liquid B is obtained by adding water to the decomposition liquid A'.
[4] The method for producing a metal phenoxide according to any one of [1] to [3], wherein the metal phenoxide is a metal alkoxide of a bisphenol compound.
[5] The method for producing a metal phenoxide according to [4], wherein the bisphenol compound of the metal alkoxide of the bisphenol compound is 2,2-bis(4-hydroxyphenyl)propane.
[6] The method for producing a metal phenoxide according to [1] to [5], wherein the metal of the metal phenoxide is an alkali metal.
[7] A method for producing an epoxy resin, comprising a step of reacting the metal phenoxide obtained by the production method according to any one of [1] to [6] with epihalohydrin.
[8] A method for producing an epoxy resin, comprising a step of reacting the epoxy resin obtained by the production method according to [7] with a polyhydric hydroxy compound.
[9] A method for producing a cured epoxy resin product, comprising a step of curing an epoxy resin composition containing the epoxy resin obtained by the production method according to [7] or [8] and a curing agent.

According to the present invention, it is possible to provide a method for efficiently obtaining metal phenoxide from a thermosetting resin decomposition product containing various products in addition to thermosetting resins such as epoxy resins. Furthermore, an epoxy resin can be produced by reacting the obtained metal phenoxide with epihalohydrin.

Embodiments of the present invention will be described in detail below, but the present invention is not limited to the following description, and can be implemented with arbitrary modifications within the scope of the gist of the present invention. In this specification, when "~" is used to express a numerical value or physical property value before and after it, it is used to include the values before and after it.

<1. Manufacturing method of metal phenoxide>
The first embodiment of the present invention is a method for producing metal phenoxide, which includes the following steps A to C.
Step A: Decompose the thermosetting resin cured product to obtain decomposed liquid A containing metal phenoxide Step B: Add water to decomposed liquid A obtained in step A to obtain oil-water two-phase liquid B Step C : A step of separating oil and water from the oil-water two-phase liquid B obtained in step B to obtain metal phenoxide.

<1-1. Metal phenoxide>
The metal phenoxide produced in this embodiment is a metal alkoxide of a phenol compound. This phenol compound is a compound derived from a thermosetting resin monomer, a curing agent, a terminal capping agent, and the like. The metal phenoxide may be a metal alkoxide of one type of phenol compound, or a mixture of metal alkoxides of two or more types of phenol compounds. Moreover, the metal of the metal phenoxide may be one type alone or a combination of two or more types of metals.

Phenol compounds include phenol, o-cresol, m-cresol, p-cresol, p-ethylphenol, p-isopropylphenol, p-tert-butylphenol, p-cumylphenol, p-cyclohexylphenol, p-octylphenol, p-nonylphenol, 2,4-xylenol, p-methoxyphenol, p-hexyloxyphenol, p-decyloxyphenol, o-chlorophenol, m-chlorophenol, p-chlorophenol, p-bromophenol, pentabromophenol , pentachlorophenol, p-phenylphenol, p-isopropenylphenol, 2,4-di(1'-methyl-1'-phenylethyl)phenol, β-naphthol, α-naphthol, p-(2',4 Monovalent phenolic compounds such as ',4'-trimethylchromanyl)phenol and 2-(4'-methoxyphenyl)-2-(4''-hydroxyphenyl)propane; hydroquinone, resorcinol, and 2-methylresorcinol Divalent phenol compounds such as 2,2'-biphenol, 4,4'-biphenol, 1,5-naphthalenediol, 2,7-naphthalenediol, bis(4-hydroxyphenyl)methane (i.e., bisphenol F) , bis{(4-hydroxy-3,5-dimethyl)phenyl}methane, 1,1-bis(4-hydroxyphenyl)ethane (i.e., bisphenol E), 1,1-bis(4-hydroxyphenyl)-1 - phenylethane (i.e., bisphenol AP), 2,2-bis(4-hydroxyphenyl)hexafluoropropane (i.e., bisphenol AF), 2,2-bis(4-hydroxyphenyl)propane (i.e., bisphenol A), 2,2-bis{(4-hydroxy-3-methyl)phenyl}propane, 2,2-bis{(4-hydroxy-3,5-dimethyl)phenyl}propane, 2,2-bis{(3,5 -dibromo-4-hydroxy)phenyl}propane, 2,2-bis{(3-isopropyl-4-hydroxy)phenyl}propane, 2,2-bis{(4-hydroxy-3-phenyl)phenyl}propane, 2 -(4-hydroxyphenyl)-2-(3-carboxy-4-hydroxyphenyl)propane, 2-(2-hydroxyphenyl)-2-(4-hydroxyphenyl)propane, 1-(4-hydroxyphenyl)- 1,3,3-trimethyl-5-hydroxyindan, 2-(4-hydroxyphenyl)-[3-{2-(4-hydroxyphenyl)propan-2-yl}-4-hydroxyphenyl]propane, 2, 2-bis(4-hydroxyphenyl)butane (i.e., bisphenol B), 1,1-bis(4-hydroxyphenyl)-1,1-diphenylmethane (i.e., bisphenol BP), 4,4'-isopropylidene bis( 2-methyl-phenol) (i.e., bisphenol C), 2,2-bis(4-hydroxy-3-isopropylphenyl)propane (i.e., bisphenol G), 2,2-bis(4-hydroxyphenyl)-3- Methylbutane, 2,2-bis(4-hydroxyphenyl)-3,3-dimethylbutane, 2,4-bis(4-hydroxyphenyl)-2-methylbutane, 2,2-bis(4-hydroxyphenyl)pentane, 2,2-bis(4-hydroxyphenyl)-4-methylpentane, 1,1-bis(4-hydroxyphenyl)cyclohexane, 1,1-bis(4-hydroxyphenyl)-4-isopropylcyclohexane, 1,1 -bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane, 9,9-bis(4-hydroxyphenyl)fluorene, 9,9-bis{(4-hydroxy-3-methyl)phenyl}fluorene, α,α'-bis(4-hydroxyphenyl)-o-diisopropylbenzene, α,α'-bis(4-hydroxyphenyl)-m-diisopropylbenzene, α,α'-bis(4-hydroxyphenyl)-p -diisopropylbenzene, 1,3-bis(4-hydroxyphenyl)-5,7-dimethyladamantane, 4,4'-dihydroxydiphenylsulfone (i.e., bisphenol S), 4,4'-dihydroxydiphenylsulfoxide, 4,4 Bisphenol compounds such as '-dihydroxydiphenyl sulfide, 4,4'-dihydroxydiphenyl ketone, 4,4'-dihydroxydiphenyl ether, and 4,4'-dihydroxydiphenyl ester; and the like.

Among these, the phenol compound is preferably a bisphenol compound, such as 2,2-bis(4-hydroxyphenyl)propane, 1,1-bis(4-hydroxyphenyl)-1-phenylethane, or 2,2-bis(4-hydroxyphenyl)propane. Bis(4-hydroxyphenyl)hexafluoropropane, 2,2-bis(4-hydroxyphenyl)butane, 1,1-bis(4-hydroxyphenyl)-1,1-diphenylmethane, 4,4'-isopropylidene bis (2-methyl-phenol), 1,1-bis(4-hydroxyphenyl)ethane, bis(4-hydroxyphenyl)methane, 2,2-bis(4-hydroxy-3-isopropylphenyl), and 4,4 It is more preferably selected from '-dihydroxydiphenylsulfone, and even more preferably 2,2-bis(4-hydroxyphenyl)propane.

The metal of the metal alkoxide of the phenol compound is not particularly limited, and includes, for example, alkali metals such as lithium, sodium, and potassium; magnesium; and aluminum; an alkali metal is preferable and selected from sodium and potassium. More preferably, it is sodium.

Therefore, the metal phenoxide produced in this embodiment is preferably a metal alkoxide of a bisphenol compound, more preferably a sodium alkoxide of a bisphenol compound, and a metal phenoxide of 2,2-bis(4-hydroxyphenyl)propane. More preferred is sodium alkoxide.

Hereinafter, metal phenoxide may be expressed as "phenol compound M (M is metal)". Specifically, for example, sodium alkoxide of bisphenol A may be written as "bisphenol A.2Na" according to the above notation.

In this embodiment, the metal phenoxide can be stably handled due to the addition of water molecules. When the added water is distilled off, the metal phenoxide decomposes, so the phenol content contained in the metal phenoxide is preferably 80% by mass or less, more preferably 70% by mass or less, and 60% by mass or less. It is more preferable that

<1-2. Process A>
Step A is a step of decomposing the cured thermosetting resin to obtain decomposed liquid A containing metal phenoxide.

(Thermosetting resin cured product)
The thermosetting resin cured product decomposed in step A is obtained by curing the thermosetting resin without using a curing agent or using a curing agent.

The thermosetting resin of the thermosetting resin cured product is not particularly limited, and may include a copolymer of the above-mentioned phenol compound and other monomer, a homopolymer of the epoxidized phenol compound mentioned above, and the above-mentioned phenol. Examples include copolymers of epoxidized compounds and other monomers. Examples of such thermosetting resins include epoxy resins and phenol resins. Among thermosetting resins, epoxy resin is a resin that has an epoxy group as a constituent, and phenol resin is a resin that has phenol, an aromatic compound, as a constituent. The thermosetting resin cured product may be a cured product of one type of thermosetting resin, or may be a cured product of two or more types of thermosetting resins.

Epoxy resins are not particularly limited, and include, for example, bisphenol A epoxy resin, bisphenol F epoxy resin, bisphenol S epoxy resin, alicyclic epoxy resin, aliphatic chain epoxy resin, phenol novolac epoxy resin, and cresol novolak. type epoxy resin, bisphenol A novolak type epoxy resin, diglycidyl etherified biphenol, diglycidyl etherified naphthalene diol, diglycidyl etherified phenol compound, diglycidyl etherified alcohol compound, alkyl substituted products of these, Examples include halides and hydrogenated products thereof. One type of epoxy resin may be used alone, or two or more types may be used in combination.

Examples of curing agents for thermosetting resins include acid anhydrides, amine compounds, phenol compounds, and isocyanate compounds. One type of curing agent may be used alone, or two or more types may be used in combination.

Further, the curing accelerator used when curing the thermosetting resin is not particularly limited, and examples thereof include alkali metal compounds, imidazole compounds, tertiary amine compounds, quaternary ammonium salts, organic phosphorus compounds, etc. . One type of curing accelerator may be used alone, or two or more types may be used in combination.

The cured thermosetting resin may be mixed with other components to form a composite material within a range that does not impede the effects of the present invention. Examples of other components include inorganic substances such as carbon, glass, metals, and metal compounds; thermoplastic resins such as polyethylene and polypropylene; and the like. Examples of the shape of the inorganic substance include fibers, particles, foils, and the like. The fibers may be in the form of a non-woven fabric or a woven fabric. In the case of a woven fabric, the fibers may be a cloth material made by weaving fiber bundles, or a UD (Uni -Direction) material. The inorganic substances may contain one type alone or two or more types.

(Disassembly method)
As the decomposition method for the cured thermosetting resin, a known decomposition method for the cured thermosetting resin or a decomposition method similar to the known decomposition method, which can generate metal phenoxide, may be adopted as appropriate. can. Preferred examples of known methods include a method in which a treatment liquid containing a decomposition catalyst and an organic solvent is brought into contact with a cured thermosetting resin.

The decomposition catalyst contained in the treatment liquid is not particularly limited as long as it can decompose the cured thermosetting resin to generate metal phenoxide. Examples of decomposition catalysts include metal hydrides, hydroxides, borohydrides, amide compounds, fluorides, chlorides, bromides, iodides, borates, phosphates, carbonates, sulfates, nitrates, Examples include organic acid salts and alkoxides. The metal contained in the decomposition catalyst is the same metal as the metal phenoxide to be produced, that is, alkali metals such as lithium, sodium, and potassium; magnesium; and aluminum; etc., and is preferably an alkali metal. More preferred is sodium. In addition, one type of decomposition catalyst may be used alone, or two or more types may be used in combination.

Among the above-mentioned compounds, the decomposition catalyst is preferably a metal alkoxide from the viewpoint of suppressing corrosion of the reaction vessel, thinning of the reaction vessel, and contamination of products caused by corrosion of the reaction vessel. Metal alkoxides are compounds in which the hydrogen atoms of the hydroxy groups of alcohols are replaced with metals, and can be obtained by adding metals to alcohols.

The alcohol used to obtain the metal alkoxide is not particularly limited, and includes methanol, ethanol, 1-butanol, 2-butanol, 2-methyl-1-propanol, 2-methyl-2-propanol, and 1-pentanol. , 2-pentanol, 3-pentanol, 2-methyl-1-butanol, 2-methyl-2-butanol, 3-methyl-1-butanol, 3-methyl-2-butanol, 2,2-dimethyl-1 -Propanol, 1-hexanol, 2-hexanol, 3-hexanol, 2-methyl-1-pentanol, 4-methyl-2-pentanol, 2-ethyl-1-butanol, 1-heptanol, 2-heptanol, 3 -Heptanol, 2-ethylhexanol, dodecanol, cyclohexanol, 1-methylcyclohexanol, 2-methylcyclohexanol, 3-methylcyclohexanol, 4-methylcyclohexanol, benzyl alcohol, phenoxyethanol, 1-(2-hydroxyethyl) -2-pyrrolidone, diacetone alcohol, ethylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, diethylene glycol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, Diethylene glycol monobutyl ether, triethylene glycol, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, tetraethylene glycol, polyethylene glycol (molecular weight 200-400), 1,2-propanediol, 1,3-propanediol, 1, Examples include 2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,5-pentanediol, glycerin, and dipropylene glycol. These alcohols may be used alone or in combination of two or more.

The metal alkoxide may be in a solid state or in a solution state. From the viewpoint of decomposition efficiency of thermosetting resin cured products, metal alkoxides include sodium methoxide, sodium ethoxide, sodium propoxide, sodium isopropoxide, sodium benzyl alkoxide (sodium benzyl oxide), potassium methoxide, and potassium ethoxide. It is preferably selected from potassium propoxide, potassium propoxide, isopropoxide, and potassium benzyl alkoxide (potassium benzyl oxide).

These alkali metal alkoxides may be used alone or in combination of two or more.

The organic solvent is not particularly limited, and examples thereof include alcohol solvents, ether solvents, aromatic solvents, and the like.

Alcohol solvents are not particularly limited, and include 1-butanol, 2-butanol, 2-methyl-1-propanol, 2-methyl-2-propanol, 1-pentanol, 2-pentanol, 3-pentanol, 2 -Methyl-1-butanol, 2-methyl-2-butanol, 3-methyl-1-butanol, 3-methyl-2-butanol, 2,2-dimethyl-1-propanol, 1-hexanol, 2-hexanol, 3 -Hexanol, 2-methyl-1-pentanol, 4-methyl-2-pentanol, 2-ethyl-1-butanol, 1-heptanol, 2-heptanol, 3-heptanol, 2-ethylhexanol, dodecanol, cyclohexanol , 1-methylcyclohexanol, 2-methylcyclohexanol, 3-methylcyclohexanol, 4-methylcyclohexanol, benzyl alcohol, and phenoxyethanol. One type of alcohol solvent may be used alone, or two or more types may be used in combination.

The ether solvent is not particularly limited, and examples include diethyl ether, dipropyl ether, dibutyl ether, butyl methyl ether, butyl ethyl ether, diisoamyl ether, hexyl methyl ether, octyl methyl ether, cyclopentyl methyl ether, and dicyclopentyl ether. Can be mentioned. One type of ether solvent may be used alone, or two or more types may be used in combination.

The aromatic solvent is not particularly limited, and examples include alkylbenzenes such as benzene, toluene, xylene, trimethylbenzene, and ethylbenzene, and alkylnaphthalenes such as methylnaphthalene, ethylnaphthalene, and dimethylnaphthalene. One type of aromatic solvent may be used alone, or two or more types may be used in combination.

Furthermore, one or more alcoholic solvents and one or more ether solvents may be used in combination, or one or more alcoholic solvents and one or more aromatic solvents may be used together. One or more types of ether solvents may be used in combination with one or more types of aromatic solvents, and one or more types of alcohol solvents may be used together. One or more kinds of ether solvents and one or more kinds of aromatic solvents may be used in combination.

Among these, alcohol-based solvents are preferred because they have excellent solubility in decomposed products of cured thermosetting resins. When a metal alkoxide is used as a decomposition catalyst, it is preferable that at least a portion of the organic solvent contains the same alcoholic solvent as the raw material alcohol for the metal alkoxide.

Further, the organic solvent is preferably an organic solvent having a boiling point of 100°C or higher under atmospheric pressure, and preferably 120°C or higher, from the viewpoint that heating is required to decompose the cured thermosetting resin. Preferably, the temperature is particularly preferably 150°C or higher.
Also from this point of view, benzyl alcohol (boiling point 205°C) is a preferred organic solvent.

The treatment liquid may further contain components other than the decomposition catalyst and the organic solvent, if necessary. Other components include surfactants, low viscosity solvents, and the like.

The concentration of the decomposition catalyst in the treatment liquid is preferably 0.001 mol/L or more and 100 mol/L or less, and 0.005 mol/L or more and 50 mol/L or less, from the viewpoint of improving the decomposition efficiency of the thermosetting resin cured product. More preferably, it is 0.01 mol/L or more and 20 mol/L or less. The higher the concentration of the decomposition catalyst, the more efficiently the cured thermosetting resin can be decomposed. The lower the concentration of the decomposition catalyst, the more the cured thermosetting resin can be decomposed without increasing the viscosity of the treatment liquid.

In preparing the treatment liquid, the decomposition catalyst may be mixed with an organic solvent in a solid state or may be mixed with an organic solvent in a solution state. In preparing the treatment liquid, there is no need to perform heating, and the treatment liquid can be prepared by mixing the organic solvent and the decomposition catalyst at room temperature of about 5 to 35°C.

The reaction vessel used when bringing the treatment liquid into contact with the cured thermosetting resin is preferably a vessel containing stainless steel from the viewpoint of corrosion prevention. Examples of the stainless steel include, but are not limited to, austenitic stainless steel, ferritic stainless steel, martensitic stainless steel, austenitic/ferritic stainless steel, and precipitation hardening stainless steel, with austenitic stainless steel being preferred. , particularly preferably SUS304, SUS316, or SUS316L.

The reaction container is not particularly limited as long as it is possible to bring the treatment liquid and the cured thermosetting resin into contact with each other. Any container that can be used as a decomposition tank may be box-shaped, cylindrical, mesh-like cage-shaped, or made of porous material. .
The volume ratio (filling rate) of the cured thermosetting resin placed in the container to the volume of the container is preferably within the range of 5% to 25% from the viewpoint of dissolution efficiency.

The heating temperature of the treatment liquid when bringing the treatment liquid into contact with the cured thermosetting resin is preferably 100°C or higher, more preferably 130°C or higher, from the viewpoint of improving the decomposition efficiency of the cured thermosetting resin. A temperature of 150°C or higher is particularly preferred. On the other hand, this temperature is preferably 300°C or lower, particularly 250°C or lower, from the viewpoint of suppressing denaturation of the solvent and decomposition products.

The contact time between the treatment liquid and the cured thermosetting resin may be sufficient to sufficiently decompose and dissolve the cured thermosetting resin, and depends on the type of thermosetting resin, the decomposition catalyst used, and the organic solvent used. Although it varies depending on the type, concentration, and processing temperature, it is usually possible to decompose and dissolve 50% by weight or more of the cured thermosetting resin in about 2 to 50 hours.

<1-3. Process B>
Step B is a step in which water is added to the decomposition liquid A obtained in step A to obtain an oil-water two-phase liquid B. Through this step, metal phenoxides contained in the decomposed liquid A are selectively extracted into the aqueous phase. On the other hand, since the decomposition products of cured thermosetting resins other than metal phenoxides are insoluble or poorly soluble in water, most of them remain in the oil phase (ie, organic phase). Therefore, according to the manufacturing method according to the present embodiment, it is possible to selectively recover metal phenoxide from the decomposition product of the cured thermosetting resin.

The water added to the decomposition liquid A is not particularly limited, and may be, for example, tap water, distilled water, ion exchange water, ultrapure water, or the like.
Furthermore, water may be added to the decomposition solution A in the form of an acid aqueous solution in which an acid is dissolved, but in order to avoid converting the metal phenoxide into a phenol compound, water that does not substantially contain an acid is added. It is preferable. Note that "substantially acid-free water" means that it is not an acid aqueous solution in which an acid is intentionally added to the water; It is not intended to exclude water containing dissolved carbon dioxide.
When the water contains an acid, the allowable amount of the acid is preferably such that the aqueous phase of the oil-water two-phase liquid B is not neutralized. The specific permissible amount of acid is such that the pH (25°C) of the aqueous phase of the oil-water two-phase liquid B is preferably 3.0 or higher, more preferably 4.0 or higher, and still more preferably 5.0 or higher. be.

The amount of water added to decomposition liquid A is an amount that can sufficiently extract the metal phenoxide produced in step A, and when the water contains an acid, the pH of the aqueous phase of oil-water two-phase liquid B is within the above range. There is no particular limitation as long as the amount falls within the range. Specifically, the weight ratio of water to the decomposition liquid is preferably 0.001 or more and 1000 or less, more preferably 0.010 or more and 100 or less, and even more preferably 0.050 or more and 10 or less. preferable. If the amount of water is at least the above lower limit, metal phenoxides can be sufficiently extracted. Moreover, if the amount of the organic solvent is below the above upper limit, high production efficiency can be ensured without requiring a large-sized container for extraction of metal phenoxide.

In step B, the decomposed liquid A obtained in step A is solid-liquid separated to remove insoluble matter to obtain a decomposed liquid A', and water is added to the decomposed liquid A' to form an oil-water two-phase liquid B. It may be a step of obtaining. Insoluble matter is, for example, something that remains in the decomposition liquid A without being decomposed together with the cured thermosetting resin in step A, and does not dissolve in either the aqueous phase or the organic phase of the oil-water two-phase liquid B. be. Examples of the insoluble matter include inorganic substances and thermoplastic resins contained in the cured thermosetting resin; other impurities; and the like. When the decomposition liquid A contains insoluble matter, by performing step B as described above, the insoluble matter is removed and the purity of the metal phenoxide can be increased.

<1-4. Process C>
Step C is a step of separating oil and water from the oil-water two-phase liquid B obtained in step B to obtain a metal phenoxide. In the oil-water two-phase liquid B, the metal phenoxide is extracted into the aqueous phase, so an aqueous solution of the metal phenoxide can be obtained by separating the oil and water and recovering the aqueous phase.

Step C may include the following steps D to E.
Step D: Separate the oil-water two-phase liquid B obtained in step B, and mix the obtained aqueous phase C and an organic solvent to obtain suspension D. Step E: The suspension obtained in step D. Step of separating turbid liquid D into solid and liquid and obtaining metal phenoxide from the solid phase

Step D is a step in which the metal phenoxide dissolved in the aqueous phase C is precipitated (crystallized) using an organic solvent, which is a poor solvent, to prepare a suspension D. Step E is a step in which the precipitated metal phenoxide is recovered by solid-liquid separation, and the metal phenoxide is recovered as a solid substance.

The organic solvent used in step D is not particularly limited as long as it is a solvent in which the metal phenoxide has low solubility and is soluble in water, such as a ketone solvent having 1 to 8 carbon atoms such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; Alcohol solvents having 1 to 6 carbon atoms such as methanol, ethanol, propanol, isopropanol, butanol, and isobutanol; ether solvents having 1 to 6 carbon atoms such as dimethyl ether, diethyl ether, and dipropyl ether; and the like. Among these, the organic solvent is preferably a ketone solvent, and more preferably acetone, since the metal phenoxide can be efficiently precipitated.

The method of mixing the aqueous phase C and the organic solvent in step D is not particularly limited, but from the viewpoint of reducing the amount of organic solvent used and precipitating the metal phenoxide in a short time, the aqueous phase C may be added dropwise to the organic solvent. A method in which the water in the aqueous phase C is distilled off by distillation under reduced pressure and then mixed with an organic solvent, or a method in which the water in the aqueous phase C is distilled off by distillation under reduced pressure and then mixed with an organic solvent. A dripping method is preferred.

In step D, the weight ratio of the organic solvent to the aqueous phase C is preferably 0.001 or more and 1000 or less, more preferably 0.010 or more and 100 or less, and preferably 0.050 or more and 10 or less. More preferred. If the amount of the organic solvent is at least the above lower limit, the metal phenoxide can be sufficiently precipitated. Moreover, if the amount of the organic solvent is below the above upper limit, high production efficiency can be ensured without requiring a large-sized container for precipitation of the metal phenoxide.

Further, the temperature of the system in which the organic solvent and the aqueous phase C are mixed is preferably at most the boiling point of the organic solvent, more preferably at most 70°C, and even more preferably at most 50°C.

The solid-liquid separation method in Step E is not particularly limited, and methods such as filtration, decantation, specific gravity separation, and centrifugation can be used. Although filtration may be performed under normal pressure, the time required for separation can be shortened by performing it under increased pressure or reduced pressure.

<2. Manufacturing method of epoxy resin>
The second embodiment of the present invention is a method for producing an epoxy resin, which includes a step of reacting the metal phenoxide obtained by the production method according to the first embodiment of the present invention with epihalohydrin. In embodiments, epihalohydrins include epichlorohydrin and epibromohydrin, preferably epichlorohydrin.
Since the manufacturing method according to this embodiment uses metal phenoxide obtained by decomposing a thermosetting resin cured product as a raw material, the epoxy resin manufactured by the manufacturing method according to this embodiment will be referred to as "recycled" hereinafter. Sometimes called epoxy resin.

In the manufacturing method according to the present embodiment, a recycled epoxy resin can be manufactured in accordance with a known one-step method for manufacturing recycled epoxy resin. A one-step method for producing a recycled epoxy resin is a method in which a hydroxy compound raw material is reacted with epihalohydrin to obtain a recycled epoxy resin. In this embodiment, at least a part of the hydroxy compound raw material is a metal phenoxide obtained by the production method according to the first embodiment of the present invention. The hydroxy compound raw material may contain a polyvalent hydroxy compound (hereinafter sometimes referred to as "another polyvalent hydroxy compound") in addition to the metal phenoxide.

Here, "other polyhydric hydroxy compounds" is a general term for divalent or higher phenol compounds and divalent or higher alcohol compounds. In the one-step method for producing recycled epoxy resin, the "hydroxy compound raw material" is a total hydroxy compound including a metal phenoxide and other polyhydric hydroxy compounds used as necessary.

Other polyhydric hydroxy compounds include bisphenol A, tetramethylbisphenol A, bisphenol F, tetramethylbisphenol F, bisphenol S, bisphenol C, bisphenol AD, bisphenol AF, hydroquinone, resorcinol, methylresorcinol, biphenol, tetramethylbiphenol, Dihydroxynaphthalene, dihydroxydiphenyl ether, thiodiphenols, phenol novolak resin, cresol novolak resin, phenol aralkyl resin, biphenylaralkyl 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 novolac resin; polyhydric phenol resins obtained by condensation reactions of various phenols with various aldehydes such as benzaldehyde, hydroxybenzaldehyde, crotonaldehyde, and glyoxal. Polyhydric phenol resins obtained by the condensation reaction of xylene resin and phenols; Various phenolic resins such as co-condensation resins of heavy oil or pitch, phenols, and formaldehyde; ethylene glycol, trimethylene Chain-like glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, 1,3-pentanediol, 1,4-pentanediol, 1,5-pentanediol, 1,6-hexanediol, etc. Examples include aliphatic diols; cycloaliphatic diols such as cyclohexane diol and cyclodecanediol; polyalkylene ether glycols such as polyethylene ether glycol, polyoxytrimethylene ether glycol, and polypropylene ether glycol; and the like.

During the reaction, metal phenoxides and other polyhydric hydroxy compounds are dissolved in epihalohydrin to form a homogeneous solution.

The amount of epihalohydrin used is preferably an amount corresponding to usually 1.0 to 14.0 equivalents, particularly 2.0 to 10.0 equivalents, per equivalent of the total hydroxyl groups of the hydroxy compound raw material (all hydroxy compounds). It is preferable that the amount of epihalohydrin is equal to or higher than the above lower limit because it is easy to control the polymerization reaction and the resulting recycled epoxy resin can have an appropriate epoxy equivalent. On the other hand, it is preferable that the amount of epihalohydrin is below the above upper limit because production efficiency tends to improve.

Next, while stirring the above solution, an amount of alkali metal hydroxide corresponding to usually 0.1 to 3.0 equivalents, preferably 0.8 to 2.0 equivalents per equivalent of total hydroxyl groups of the hydroxy compound raw material is added to the solid. Or add it as an aqueous solution and react. It is preferable that the amount of the alkali metal hydroxide added is equal to or higher than the above lower limit because it is difficult for unreacted hydroxyl groups to react with the generated epoxy resin and the polymerization reaction is easily controlled. Further, it is preferable that the amount of the alkali metal hydroxide added is below the above upper limit because impurities due to side reactions are less likely to be generated. The alkali metal hydroxide used here usually includes sodium hydroxide or potassium hydroxide.

This reaction can be carried out under normal pressure or reduced pressure, and the reaction temperature is preferably 20 to 200°C, more preferably 40 to 150°C. It is preferable that the reaction temperature is equal to or higher than the above lower limit because the reaction can easily proceed and the reaction can be easily controlled. Moreover, it is preferable that the reaction temperature is below the above upper limit because side reactions are difficult to proceed and it is particularly easy to reduce the amount of polymer.

In addition, this reaction involves azeotropically distilling the reaction liquid while maintaining a predetermined temperature as necessary, cooling the evaporating vapor, separating the resulting condensate from oil/water, and removing the water from the oil. This is done while dehydrating by returning it to the system. The alkali metal hydroxide is preferably added intermittently or continuously in small amounts over a period of 0.1 to 24 hours, more preferably 0.5 to 10 hours, in order to suppress rapid reactions. It is preferable that the addition time of the alkali metal hydroxide is at least the above-mentioned lower limit because it is possible to prevent the reaction from proceeding rapidly and the reaction temperature can be easily controlled. It is preferable that the addition time is equal to or less than the above upper limit because the amount of polymer can be easily reduced.

After completion of the reaction, insoluble by-product salts are removed by filtration or washing with water, and unreacted epihalohydrin can be removed by heating and/or distillation under reduced pressure.

In addition, 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 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; dimethyl sulfoxide and dimethyl formamide Inert organic solvents such as aprotic polar solvents such as; etc. may also be used.

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

An organic solvent for dissolving the recycled epoxy resin may be used for the reaction with the alkali. The organic solvent used in the reaction is not particularly limited, but it is preferable to use a ketone-based organic solvent from the viewpoints of production efficiency, ease of handling, workability, and the like. Furthermore, from the viewpoint of further lowering the amount of hydrolyzable chlorine, an aprotic polar solvent may be used.

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 in terms of effectiveness and ease of post-treatment. These may be used alone or in combination of two or more.

Examples of the aprotic polar solvent include dimethylsulfoxide, diethylsulfoxide, dimethylsulfone, sulfolane, dimethylformamide, dimethylacetamide, hexamethylphosphoramide, and the like. These may be used alone or in combination of two or more. Among these aprotic polar solvents, dimethyl sulfoxide is preferred because it is easily available and has excellent effects.

The amount of the above solvent used is such that the concentration of the recycled epoxy resin in the solution subjected to alkali treatment 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 the alkali metal hydroxide include potassium hydroxide and sodium hydroxide, with sodium hydroxide being preferred. Furthermore, 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 used is preferably 0.01 to 20.0 parts by mass or less based on 100 parts by mass of the recycled 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. When the amount of alkali metal hydroxide used is below the above-mentioned lower limit, the effect of reducing the total chlorine content is low, and when it is above the above-mentioned upper limit, a large amount of polymer is produced, resulting in a decrease in yield.

The reaction temperature is preferably 20 to 200°C, more preferably 40 to 150°C, and the reaction time is preferably 0.1 to 24 hours, more preferably 0.5 to 10 hours.
After the reaction, excess alkali metal hydroxide and secondary salts can be removed by washing with water or the like, and the organic solvent can be further removed by heating and/or distillation under reduced pressure and/or steam distillation.

<3. Manufacturing method of epoxy resin>
The third embodiment of the present invention is a method for producing an epoxy resin, which includes a step of reacting the epoxy resin obtained by the production method according to the second embodiment of the present invention with a polyhydric hydroxy compound. The polyhydric hydroxy compound in this embodiment is a general term for dihydric or higher phenol compounds and divalent or higher alcohols.
Since the manufacturing method according to this embodiment uses metal phenoxide obtained by decomposing a thermosetting resin cured product as a raw material, the epoxy resin manufactured by the manufacturing method according to this embodiment will be referred to as "recycled" hereinafter. Sometimes called epoxy resin.

In the manufacturing method according to the present embodiment, a recycled epoxy resin can be manufactured in accordance with a known two-step method for manufacturing recycled epoxy resin. The two-step method for producing recycled epoxy resin includes a step of reacting an epoxy resin raw material and a polyhydric hydroxy compound raw material. In this embodiment, at least a part of the epoxy resin raw material is an epoxy resin obtained by the manufacturing method according to the second embodiment of the present invention.

That is, the method for producing recycled epoxy resin using a two-step method uses an epoxy resin raw material containing the epoxy resin obtained by the production method according to the second embodiment of the present invention and a polyvalent hydroxy compound raw material containing a polyvalent hydroxy compound. This is a method of causing a reaction.

The epoxy resin raw material may contain other epoxy resins as necessary in addition to the epoxy resin obtained by the manufacturing method according to the second embodiment of the present invention.

Other epoxy resins are as described later in the method for producing a cured epoxy resin according to the fourth embodiment of the present invention, and the polyhydric hydroxy compound is the same as that of the recycled epoxy resin according to the fourth embodiment of the present invention. The same applies to other polyhydric hydroxy compounds in the manufacturing method.

The content of recycled epoxy resin in the epoxy resin raw material is not particularly limited, but since a high content of recycled epoxy resin 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 should be such that their compounding equivalent ratio is (epoxy group equivalent): (hydroxyl group equivalent) = 1:0.1 to 2.0. It is preferable to More preferably, the ratio is 1:0.2 to 1.2. It is preferable that this equivalent ratio is within the above range because it facilitates the increase in molecular weight and allows more epoxy group terminals to remain.

In addition, a catalyst may be used in the two-step reaction, and any compound that has a catalytic ability to promote the reaction between an epoxy group and a phenolic hydroxyl group or an alcoholic hydroxyl group can be used as the catalyst. But that's fine. Examples 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. Moreover, only one type of catalyst can be used, 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 may be used as long as it dissolves the epoxy resin raw material. Examples include aromatic solvents, ketone solvents, amide solvents, glycol ether solvents, and the like. One type of solvent may be used alone, or two or more types may be used in combination. Further, the resin concentration in the solvent is preferably 10 to 95% by mass. More preferably 20 to 80% by mass. Further, if a highly viscous product is generated during the reaction, the reaction can be continued by additionally adding a solvent. After the reaction is completed, the solvent can be removed or further added as necessary.

In the two-stage reaction, the reaction temperature is preferably 20 to 250°C, more preferably 50 to 200°C. When the reaction temperature is higher than the above upper limit, there is a risk that the produced epoxy resin will deteriorate. Further, if the amount 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.

<4. Method for producing cured epoxy resin>
A fourth embodiment of the present invention provides an epoxy resin comprising a step of curing an epoxy resin composition containing a recycled epoxy resin and a curing agent obtained by the production method according to the second or third embodiment of the present invention. This is a method for producing a cured product. It is also possible to obtain a composite material again by further blending an inorganic substance into the epoxy resin composition and curing this epoxy resin composition. According to this embodiment, a new chemical recycling can be established in this way.

In this embodiment, the epoxy resin composition may include other epoxy resins, a curing agent, and a curing accelerator other than the recycled epoxy resin obtained by the manufacturing method according to the second or third embodiment of the present invention. , an inorganic filler, a coupling agent, and the like can be appropriately blended.

The content of recycled epoxy resin in the epoxy resin composition is not particularly limited. Since a high content of recycled epoxy resin is environmentally friendly, the recycled epoxy resin is preferably 40 parts by mass or more, more preferably 60 parts by mass or more, based on 100 parts by mass of all epoxy resin components in the epoxy resin composition. When other epoxy resins are included, the amount of recycled epoxy resin can be 40 to 99 parts by mass, 60 to 99 parts by mass, etc., based on 100 parts by mass of all epoxy resin components in the epoxy resin composition. Note that "all epoxy resin components" 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.

(hardening agent)
The curing agent contained in the epoxy resin composition refers to a substance that contributes to the crosslinking reaction and/or chain lengthening reaction between epoxy groups of the epoxy resin. In addition, in this embodiment, even if it is normally called a "curing accelerator", if it contributes to the crosslinking reaction and/or chain lengthening reaction between the epoxy groups of the epoxy resin, it is considered to be a curing agent. That's it.

In the epoxy resin composition, the content of the curing agent is preferably 0.1 to 1000 parts by mass based on 100 parts by mass of all epoxy resin components. Moreover, it is more preferably 500 parts by mass or less.

There are no particular limitations on the curing agent, and all commonly known epoxy resin curing agents can be used. For example, amine curing agents such as phenolic curing agents, aliphatic amines, polyether amines, alicyclic amines, and aromatic amines; acid anhydride curing agents; amide curing agents; tertiary amines; imidazoles ; etc. One type of curing agent may be used alone, or two or more types may be used in combination. When using two or more types of curing agents in combination, they may be mixed in advance to prepare a mixed curing agent before use, or the recycled material obtained by the manufacturing method according to the second or third embodiment of the present invention may be used. When mixing each component such as the epoxy resin and other epoxy resins, each component of the curing agent may be added separately and mixed at the same time.

Specific examples of phenolic curing agents include bisphenol compounds, 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, biphenylaralkyl resin, naphthol aralkyl resin, terpene phenol resin, dicyclopentadiene phenol resin, bisphenol A novolak resin, Various polyhydric phenols such as trisphenol methane type resin, naphthol novolac resin, brominated bisphenol A, brominated phenol novolac resin, various phenols and various aldehydes such as benzaldehyde, hydroxybenzaldehyde, crotonaldehyde, glyoxal, etc. Polyphenol resins obtained by condensation reaction, polyphenol resins obtained by condensation reaction of xylene resin and phenols, co-condensation resins of heavy oil or pitch, phenol and formaldehyde, phenol/benzaldehyde・Xylylene dimethoxide polycondensate, phenol/benzaldehyde/xylylene dihalide polycondensate, phenol/benzaldehyde/4,4'-dimethoxide biphenyl polycondensate, phenol/benzaldehyde/4,4'-dihalide biphenyl polycondensate Examples include various phenolic resins such as condensates.

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

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

Examples of amine curing agents (excluding tertiary amines) include aliphatic amines, polyether amines, alicyclic amines, and aromatic amines.

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

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

Alicyclic amines include isophorone diamine, methacene diamine, N-aminoethylpiperazine, bis(4-amino-3-methyldicyclohexyl)methane, bis(aminomethyl)cyclohexane, 3,9-bis(3-amino Examples include propyl)-2,4,8,10-tetraoxaspiro(5,5)undecane and norbornenediamine.

Aromatic amines include tetrachloro-p-xylene diamine, m-xylene diamine, p-xylene diamine, m-phenylene diamine, o-phenylene diamine, p-phenylene diamine, 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, and α,α'-bis(4-aminophenyl)-p-diisopropylbenzene.

The above-mentioned amine curing agents may be used alone or in combination of two or more in arbitrary combinations and blending ratios.

The above amine curing agent can be used in such a manner 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.

Examples of tertiary amines include 1,8-diazabicyclo(5,4,0)undecene-7, triethylenediamine, benzyldimethylamine, triethanolamine, dimethylaminoethanol, tris(dimethylaminomethyl)phenol, etc. .
The above-mentioned tertiary amines may be used alone or in combination of two or more in arbitrary combinations and blending ratios.

The above-mentioned tertiary amine 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.

Examples of the acid anhydride curing agent include acid anhydrides and modified products of 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(ethyl octadecanedioic acid) anhydride, poly(phenylhexadecanedioic acid) anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, hexahydrophthalic anhydride , methylhimic anhydride, trialkyltetrahydrophthalic anhydride, methylcyclohexenedicarboxylic anhydride, methylcyclohexenetetracarboxylic anhydride, ethylene glycol bistrimelitate dianhydride, Het's acid anhydride, nadic acid anhydride, Methylnadic anhydride, 5-(2,5-dioxotetrahydro-3-furanyl)-3-methyl-3-cyclohexane-1,2-dicarboxylic anhydride, 3,4-dicarboxy-1,2, 3,4-tetrahydro-1-naphthalenesuccinic dianhydride, and 1-
Examples include methyl-dicarboxy-1,2,3,4-tetrahydro-1-naphthalenesuccinic dianhydride.

Examples of modified acid anhydrides include 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; etc. Furthermore, a copolymerized polyether glycol of two or more of these glycols and/or polyether glycols can also be used.

The acid anhydride curing agents listed above may be used alone or in combination of two or more in arbitrary combinations and amounts.

When using an acid anhydride curing agent, it should 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 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.

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

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 isocyanuric acid adduct, 2-phenylimidazole isocyanuric acid adduct, 2-phenyl-4,5 Examples include -dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, and adducts of epoxy resins and the above imidazoles. Since imidazoles have catalytic ability, they can generally be classified as curing accelerators, but in the present invention they are classified as curing agents.
The imidazoles listed above may be used alone or in combination of two or more in any desired ratio.

When imidazoles are used, it is preferable to use them 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.

In the epoxy resin composition, other curing agents can be used in addition to the above-mentioned curing agents. Other curing agents that can be used in the epoxy resin composition are not particularly limited, and any curing agents that are 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 further contain other epoxy resins (other epoxy resins) in addition to the recycled epoxy resin obtained by the manufacturing method according to the second or third embodiment of the present invention. By including other epoxy resins, various physical properties can be improved.

Other epoxy resins that can be used in the epoxy resin composition include all epoxy resins other than the recycled epoxy resin obtained by the manufacturing method according to the second or third embodiment of the present invention. Specific examples include bisphenol A epoxy resin, bisphenol C epoxy resin, trisphenolmethane epoxy resin, anthracene epoxy resin, phenol-modified xylene resin epoxy resin, bisphenol cyclododecyl epoxy resin, and bisphenol diisopropylidene resorcinol. Epoxy resin, bisphenol F epoxy resin, bisphenol AD epoxy resin, bisphenol AF epoxy resin, hydroquinone epoxy resin, methylhydroquinone epoxy resin, dibutylhydroquinone epoxy resin, resorcinol epoxy resin, methylresorcinol epoxy resin, biphenol type epoxy resin, tetramethylbiphenol type epoxy resin, tetramethylbisphenol type 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 novolac type epoxy resin, bisphenol A novolac type epoxy resin, naphthol novolak type epoxy resin, phenol aralkyl type Epoxy resin, naphthol aralkyl epoxy resin, biphenylaralkyl epoxy resin, terpene phenol epoxy resin, dicyclopentadiene phenol epoxy resin, epoxy resin derived from a condensate of phenol/hydroxybenzaldehyde, condensate of phenol/crotonaldehyde Epoxy resins derived from phenol-glyoxal condensates, epoxy resins derived from co-condensation resins of heavy oils or pitches, phenols and formaldehydes, epoxy resins derived from diaminodiphenylmethane Examples include epoxy resin, epoxy resin derived from aminophenol, epoxy resin derived from xylene diamine, epoxy resin derived from methylhexahydrophthalic acid, and epoxy resin 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 other epoxy resin described above, 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. below.

(hardening accelerator)
It is preferable that the epoxy resin composition contains a curing accelerator. By including a curing accelerator, it becomes possible to shorten the curing time and lower the curing temperature, making it easier to obtain a desired cured product.

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

Phosphorous 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 and organic borons; these organic phosphines and maleic anhydride, 1,4-benzoquinone, 2,5-torquinone, 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- Examples include compounds obtained by adding quinone compounds such as benzoquinone, and compounds such as diazophenylmethane.

Among the curing accelerators listed above, organic phosphines and phosphonium salts are preferred, and organic phosphines are most preferred. Moreover, among the curing accelerators listed above, only one type may be used, or two or more types may be used in a mixture in any combination and ratio.

The curing accelerator is preferably used in an amount of 0.1 parts by mass or more and 20 parts by mass or less based on 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-mentioned lower limit, a good curing accelerating effect can be obtained, while when it is at most the above-mentioned upper limit, desired cured physical properties can be easily obtained, which is preferable.

(Inorganic filler)
An inorganic filler can be added to 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 in combination of two or more in any desired 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 mold release agent can be added to the epoxy resin composition. Examples of mold release agents include natural waxes such as carnauba wax, synthetic waxes such as polyethylene wax; higher fatty acids and metal salts thereof such as stearic acid and zinc stearate; hydrocarbon mold release agents such as paraffin; etc. Can be used. These may be used alone or in combination of two or more in any desired combination and blending ratio.

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

(coupling agent)
A coupling agent can be added to the epoxy resin composition. It is preferable to use the coupling agent together with the inorganic filler, and by blending the coupling agent, it is possible to improve the adhesion between the epoxy resin that is the matrix and the inorganic filler. Examples of coupling agents include silane coupling agents and titanate coupling agents.

Examples of the silane coupling agent 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 Aminosilane such as silane, mercaptosilane such as 3-mercaptopropyltrimethoxysilane, p-styryltrimethoxysilane, vinyltrichlorosilane, vinyltris(β-methoxyethoxy)silane, vinyltrimethoxysilane, vinyltriethoxysilane, γ-methacrylate Examples include vinyl silanes such as roxypropyltrimethoxysilane, and polymer type silanes such as epoxy, amino, and vinyl silanes.

Examples of the titanate coupling agent include isopropyl triisostearoyl titanate, isopropyl tri(N-aminoethyl aminoethyl) titanate, diisopropyl bis(dioctyl phosphate) titanate, tetraisopropyl bis(dioctyl phosphite) titanate, and tetraoctyl bis( ditridecyl phosphite) titanate, tetra(2,2-diallyloxymethyl-1-butyl) bis(ditridecyl) phosphite titanate, bis(dioctyl pyrophosphate) oxyacetate titanate, and bis(dioctyl pyrophosphate) ethylene titanate, etc. Can be mentioned.

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 amount thereof is preferably 0.001 to 10.0 parts by mass based on 100 parts by mass of all epoxy resin components. When the amount of the coupling agent is equal to or higher than the above lower limit, the effect of improving the adhesion between the epoxy resin that is the matrix and the inorganic filler tends to improve due to the addition of the coupling agent. It is preferable that the amount of compounded is below the above upper limit because the coupling agent is less likely to bleed out from the resulting cured product.

(Other ingredients)
The epoxy resin composition can contain components other than those mentioned above. Examples of other blended components include flame retardants, plasticizers, reactive diluents, and pigments, which can be appropriately blended as needed. However, this does not preclude the incorporation of components other than those listed above.

Examples of 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, phosphoric acid esters, and phosphines; melamine derivatives, etc. and inorganic flame retardants such as aluminum hydroxide and magnesium hydroxide.

(Curing method)
A cured epoxy resin product 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 to 250°C. Furthermore, 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. It is preferable that the reaction time is at least the above lower limit because the curing reaction tends to proceed sufficiently easily. On the other hand, it is preferable that the reaction time is equal to or less than the above upper limit because deterioration due to heating and energy loss during heating can be easily reduced.

(Application)
The cured epoxy resin obtained by curing the epoxy resin composition has a low coefficient of linear expansion and excellent heat crack resistance.
Therefore, the cured epoxy resin product can be effectively used in any application that requires these physical properties. For example, in the paint field such as electrocoating paint for automobiles, heavy anti-corrosion paint for ships and bridges, and paint for the inner surface coating of beverage cans; in the electrical and electronic field such as laminates, semiconductor encapsulation materials, insulating powder paints, and coil impregnation. Suitable for use in the civil engineering, construction, and adhesive fields such as seismic reinforcement of bridges, concrete reinforcement, flooring materials for buildings, linings for water supply facilities, drainage and permeable pavement, and adhesives for vehicles and aircraft. be able to.

The epoxy resin composition may be used after being cured for the above-mentioned use, or may be cured during the manufacturing process for the above-mentioned use.

Hereinafter, the present invention will be explained in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples unless the gist thereof is exceeded.

[Raw materials and reagents]
Bisphenol A type epoxy resin (epoxy equivalent weight: 950 and 183) and products from Mitsubishi Chemical Corporation were used.
Rikacid M-700 (acid anhydride) was a product of Shin Nippon Chemical Co., Ltd.
As Curesol 2E4MZ (curing catalyst), a product manufactured by Shikoku Kasei Kogyo Co., Ltd. was used.
As the phenol novolac resin (PSM-4261), a product manufactured by Gun-ei Chemical Industry Co., Ltd. was used.
48% by mass aqueous sodium hydroxide solution, sodium hydrogen carbonate, disylendiamide (DICY), and 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU) are products of Fuji Film Wako Pure Chemical Industries, Ltd. It was used.
Benzyl alcohol was a product of Sankyo Chemical Co., Ltd.

[analysis]
Confirmation of production, purity, and quantitative determination of bisphenol A were performed using high performance liquid chromatography under the following procedures and conditions.
・Equipment: RHPLC manufactured by JASCO, 03150-3M Unifinepak C18 3μm 150mm x 3.0mm ID manufactured by JASCO
・Method: Gradient method ・Analysis temperature: 40℃
・Eluent composition:
Solution A Acetonitrile Solution B Water At analysis time of 0 minutes, solution A:B solution = 30:70 (volume ratio, the same applies hereinafter), and at analysis time of 0 to 25 minutes, solution A:B solution was gradually changed to 100:0. .
・Flow rate: 0.40mL/min ・Detection wavelength: 280nm

<Example 1>
A mixture a was obtained by placing 500 g of bisphenol A type epoxy resin (epoxy equivalent: 950) and 10 g of a 5% by mass aqueous sodium bicarbonate solution in an aluminum cup and mixing them well. The obtained mixture a was cured at 200° C. for 100 hours to obtain a single resin cured product.

A separable flask equipped with a stirring blade, a cooling tube, and a thermometer was charged with 630 g of benzyl alcohol and 50 g of a 48% by mass aqueous sodium hydroxide solution under a nitrogen atmosphere. After creating a full vacuum inside the separable flask, the internal temperature was gradually raised and a portion of the water and benzyl alcohol was extracted, thereby completely distilling off the water inside the separable flask. By restoring the pressure inside the separable flask with nitrogen, 640 g of the treatment liquid was obtained.

After adding 60 g of the single resin cured product to 640 g of the obtained treatment liquid, the temperature was raised to 200° C. over 1 hour at normal pressure. By maintaining the internal liquid of the separable flask at 200° C. for 3 hours, the single resin cured product was completely dissolved, and 700 g of decomposed liquid a was obtained. When the composition of a portion of the obtained decomposed liquid a was confirmed by high performance liquid chromatography, it was found that it contained 4.1% by mass of bisphenol A/2Na (4.1% by mass x 700g = 28.7g). It was confirmed.

700 g of water was added to 700 g of decomposed liquid a, and 650 g of water phase a was obtained by separating oil and water at room temperature. The aqueous phase a was concentrated five times by distilling water off under reduced pressure, and the concentrated liquid was added dropwise to 2800 g of acetone to obtain suspension a. Suspension a was filtered and the filtered material was air-dried to obtain 44 g of solid substance a. When the composition of a part of the obtained solid material a was confirmed by high performance liquid chromatography, it was found that it contained 37.7% by mass of bisphenol A/2Na (37.7% by mass x 44g = 16.6g). It was confirmed.

<Comparative example 1>
In a jacketed separable flask equipped with a Dimroth condenser, a stirring blade, and a thermometer, 500 g of the decomposition liquid a obtained in Example 1 was charged under a nitrogen atmosphere, and the temperature was raised to 80°C. Decomposed liquid a was neutralized with hydrochloric acid while maintaining the internal temperature at 80°C.

Thereafter, the mixture was allowed to stand to separate oil and water, and the aqueous phase b was extracted to obtain an organic phase b. 150 g of water was added to the obtained organic phase b and mixed while maintaining the internal temperature at 80°C. Thereafter, the mixture was allowed to stand to separate oil and water, and the aqueous phase b' was extracted to obtain an organic phase b'. The temperature of the obtained organic phase b' was lowered to 10° C., but a suspension containing bisphenol A/2Na was not obtained.

<Comparative example 2>
In a jacketed separable flask equipped with a Dimroth condenser, a stirring blade, and a thermometer, 500 g of the decomposition liquid a obtained in Example 1 was charged under a nitrogen atmosphere, and the temperature was raised to 80°C. Thereafter, the temperature was lowered to 10°C, but a suspension containing bisphenol A/2Na was not obtained.

In Example 1 and Comparative Examples 1 and 2, Table 1 summarizes the presence or absence of water extraction of the decomposed liquid a, the presence or absence of neutralization, the presence or absence of crystallization, and the presence or absence of bisphenol A. From Table 1, it can be seen that bisphenol A/2Na can be obtained by performing water extraction of decomposition liquid a.

<Example 2>
Bisphenol A type epoxy resin (epoxy equivalent: 183) 300 in an aluminum cup
g, 270 g of Rikacid, and 3 g of Curesol 2E4MZ were added and mixed well to obtain a mixture C. The obtained mixture C was heated at 100°C for 3 hours, and then heated at 140°C for 3 hours to obtain an acid anhydride cured product.

The same procedure as in Example 1 was carried out except that 60 g of the acid anhydride cured product was used as the thermosetting resin to obtain 700 g of decomposition liquid c. When the composition of a part of the obtained decomposition liquid c was confirmed by high performance liquid chromatography, it was found that it contained 3.5% by mass of bisphenol A/2Na (3.5% by mass x 700g = 24.5g). It was confirmed.

Thereafter, the same procedure as in Example 1 was carried out to obtain 64.3 g of solid matter. When the composition of a part of the obtained solid c was confirmed by high performance liquid chromatography, it contained 21.9% (21.9% by mass x 64.3g = 14.1g) of bisphenol A/2Na. It was confirmed.

<Example 3>
Mixture D was obtained by putting 280 g of bisphenol A type epoxy resin (epoxy equivalent: 183), 2 g of DICY, and 3 g of DCMU into an aluminum cup and mixing well. The obtained mixture D was heated at 150° C. for 3 hours to obtain an amine cured product.

The same procedure as in Example 1 was conducted except that 60 g of the amine cured product was used as the thermosetting resin to obtain 700 g of decomposition liquid d. When the composition of a portion of the obtained decomposition liquid d was confirmed by high performance liquid chromatography, it was found that it contained 3.1% by mass of bisphenol A/2Na (3.1% by mass x 700g = 21.7g). It was confirmed.

Thereafter, the same procedure as in Example 1 was carried out to obtain 69.1 g of solid material d. When the composition of a part of the obtained solid d was confirmed by high performance liquid chromatography, it was found that 23.3% by mass (23.3% by mass x 69.1g = 16.1g) of bisphenol A/2Na was contained. I confirmed that there is.

<Example 4>
Mixture e was obtained by putting 280 g of bisphenol A type epoxy resin (epoxy equivalent: 183), 172 g of phenol novolac resin (PSM-4261), and 2 g of Curesol 2E4MZ into an aluminum cup and mixing well. The obtained mixture e was heated at 120°C for 2 hours and then at 175°C for 6 hours to obtain a phenol cured product.

The same procedure as in Example 1 was carried out except that 60 g of the cured phenol was used as the thermosetting resin to obtain 700 g of decomposed liquid e. Since insoluble matter was observed in the decomposition liquid e, the insoluble matter was filtered out to obtain a decomposition liquid e'. When the composition of a part of the obtained decomposition liquid e' was confirmed by high performance liquid chromatography, it contained 2.4% by mass of bisphenol A/2Na (2.4% by mass x 700g = 16.8g). It was confirmed.

Thereafter, the same procedure as in Example 1 was carried out to obtain 32.0 g of a solid e. When the composition of a part of the obtained solid e was confirmed by high performance liquid chromatography, it was found that it contained 28.4% by mass of bisphenol A/2Na (28.4% by mass x 32.0g = 9.1g). I confirmed that there is.

In Examples 1 to 4, the type of cured resin, the presence or absence of bisphenol A/2Na, and the purity of bisphenol A/2Na are summarized in Table 2. Table 2 shows that bisphenol A.2Na can be obtained using any of the cured resins.

<Example 5>
Into a 1 L four-necked flask equipped with a thermometer, a stirrer, and a cooling tube, 44 g of the solid material A obtained in Example 1, 259 g of epichlorohydrin, 100 g of isopropanol, and 36 g of water were charged, and the temperature was raised to 40°C and uniformly heated. After dissolving, 38 g of a 48.5% by mass aqueous sodium hydroxide 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 was maintained at 65° C. for 30 minutes to complete the reaction, and the reaction solution was transferred to a 1 L separating funnel, 69 g of water at 65° C. was added, and the mixture was allowed to stand at 65° C. for 1 hour. After standing still, the aqueous phase was extracted from the separated organic phase and aqueous phase, and by-product salt and excess sodium hydroxide were removed. After that, epichlorohydrin was completely removed under reduced pressure at 150°C, 102g of methyl isobutyl ketone was charged, and the temperature was raised to 65°C to uniformly dissolve it, followed by 1.4g of a 48.5% by mass aqueous sodium hydroxide solution. was charged and allowed to react for 60 minutes. After the reaction, 57 g of methyl isobutyl ketone was added to the reaction mixture, and the mixture was washed four times with 200 g of water. Thereafter, methyl isobutyl ketone was completely removed under reduced pressure at 150°C to obtain epoxy resin A.

The epoxy equivalent of the obtained epoxy resin A was measured according to JIS K 7236 (2009) and was found to be 230 g/equivalent.

Claims (10)

A method for producing metal phenoxide, including the following steps A to C.
Step A: Decompose the thermosetting resin cured product to obtain decomposed liquid A containing metal phenoxide Step B: Add water to decomposed liquid A obtained in step A to obtain oil-water two-phase liquid B Step C : A step of separating oil and water from the oil-water two-phase liquid B obtained in step B to obtain metal phenoxide. The method for producing a metal phenoxide according to claim 1, wherein the step C includes the following steps D to E.
Step D: Separate the oil-water two-phase liquid B obtained in step B, and mix the obtained aqueous phase C and an organic solvent to obtain suspension D. Step E: The suspension obtained in step D. Step of separating turbid liquid D into solid and liquid and obtaining metal phenoxide from the solid phase In step B, the decomposed liquid A obtained in step A is solid-liquid separated to remove insoluble matter to obtain decomposed liquid A', and water is added to the decomposed liquid A' to form an oil-water two-phase liquid. The method for producing metal phenoxide according to claim 1, wherein B is obtained. The method for producing a metal phenoxide according to claim 1, wherein the metal phenoxide is a metal alkoxide of a bisphenol compound. The method for producing a metal phenoxide according to claim 4, wherein the bisphenol compound of the metal alkoxide of the bisphenol compound is 2,2-bis(4-hydroxyphenyl)propane. The method for producing a metal phenoxide according to claim 1, wherein the metal of the metal phenoxide is an alkali metal. A method for producing an epoxy resin, comprising the step of reacting the metal phenoxide obtained by the production method according to any one of claims 1 to 6 with epihalohydrin. A method for producing an epoxy resin, comprising the step of reacting the epoxy resin obtained by the production method according to claim 7 with a polyhydric hydroxy compound. A method for producing a cured epoxy resin, comprising the step of curing an epoxy resin composition containing the epoxy resin obtained by the production method according to claim 7 and a curing agent. A method for producing a cured epoxy resin product, comprising the step of curing an epoxy resin composition containing the epoxy resin obtained by the production method according to claim 8 and a curing agent.