Dihydroxy compound production method and recycled resin production method

Abstract

Provided is a method for recycling a waste resin composition containing a synthetic resin and organic impurities.　A production method according to the present invention is for producing a dihydroxy compound from a waste resin composition, and includes: a step (a1) for treating an alkaline solution, which comprises a waste resin composition including a resin having at least two structural units selected from the group consisting of general formulas 1-4, a ketone-based solvent, and water, to obtain a reaction solution which comprises a mixture of dihydroxy compounds including a first dihydroxy compound selected from the group consisting of the general formulas 1'-4' and at least one other dihydroxy compound selected from the group consisting of said general formulas 1'-4', and a ketone-based solvent; and a step (b1) for crystallizing the first dihydroxy compound from a crystallization solution obtained by adding an alcohol-based solvent to the reaction solution.

Description

Method for producing dihydroxy compounds and method for producing recycled resins

[0001] The present invention relates to a method for producing a dihydroxy compound and a method for producing a recycled resin.

[0002] In recent years, concerns have grown over the deterioration of the natural environment and the increase in waste emissions, and there has been an increasing movement to reuse and recycle plastic products in an effort to realize a recycling-oriented society.

[0003] Synthetic resins such as polycarbonate resin, which are the main constituents of plastic products, are widely used in a variety of applications, such as home appliances, electronic and electrical equipment, office automation equipment, optical media, automobile parts, building materials, etc. During the production of the above-mentioned plastic products and after their use, a large amount of synthetic resin waste is generated, and therefore, these waste materials are being recycled.

[0004] In particular, when plastic products are manufactured by molding synthetic resins, the parts originating from the passages of the mold, such as sprues, runners, and gates, are removed to produce the plastic products. Efforts are being made to recycle and reuse waste resins, such as synthetic resins that are not needed for such plastic products and are removed, as well as other waste resins such as defective moldings, without discarding them.

[0005] For example, Patent Document 1 describes an invention relating to a method for recovering polycarbonate resin, which includes a step of crushing discarded optical discs and / or recovered optical discs having a polycarbonate resin substrate and chemically treating the resulting crushed material. The recovery method describes a step of removing magnetic metallic foreign matter from the chemically treated material obtained in the chemical treatment step using a magnet, a step of removing colored foreign matter using an optical camera, and a step of removing resin containing metallic foreign matter using a metallic foreign matter detector.

[0006] JP 2011-131507 A

[0007] The recovery method described in Patent Document 1 allows for the recovery of synthetic resins by removing metals, colored foreign matter, resins containing metal foreign matter, etc. The recovery method is carried out based on the appearance of contained metals and coloration. However, plastic products are often manufactured by combining multiple types of synthetic resins, and synthetic resins that are not needed for plastic products and are removed, such as defective molded products, contain organic impurities along with the desired synthetic resin. In such cases, the presence or absence of metals and the degree of coloration may not differ significantly between the desired synthetic resin and the organic impurities. As a result, the method described in Patent Document 1 is unable to recover and recycle the desired synthetic resin. Under these circumstances, a new method for recycling waste resin compositions is needed.

[0008] Therefore, an object of the present invention is to provide a method for recycling a waste resin composition containing synthetic resins and organic impurities.

[0009] The present invention has the following aspects, for example: [1] A method for producing a dihydroxy compound from a waste resin composition, comprising: [In the formula, X ａ , X ｂ , X ｃ , X ｄ , X ｅ , and X ｆ each independently represents an alkylene group having 1 to 4 carbon atoms; ａ , R ｂ , R ｃ , R ｃｃ , R ｄ , R ｄｄ , R ｅ , R ｅｅ , R ｆ、 and R ｆｆ each independently represents a halogen atom, an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, a cycloalkyl group having 5 to 20 carbon atoms, a cycloalkoxy group having 5 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, a heteroaryl group having 3 to 20 carbon atoms containing one or more hetero ring atoms selected from O, N, and S, an aryloxy group having 6 to 20 carbon atoms, and —C≡C—R ｉ is selected from Rｉ represents an aryl group having 6 to 20 carbon atoms or a heteroaryl group having 3 to 20 carbon atoms and containing one or more hetero ring atoms selected from O, N, and S; a, b, c, d, e, and f each independently represent an integer of 0 to 10; h, i, j, j', k, k', m, m', n, and n' each independently represent an integer of 0 to 4; R ｇ each independently represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.], and an alkaline solution containing a ketone solvent and water is treated to produce a compound represented by the following general formulas (1') to (4'): [wherein each symbol has the same meaning as in the above general formulas (1) to (4)]. A production method comprising: a step (a1) of obtaining a reaction solution containing a mixture of dihydroxy compounds, the mixture including a first dihydroxy compound selected from the group consisting of the general formulas (1') to (4'), and at least one other dihydroxy compound selected from the group consisting of the general formulas (1') to (4'), and a ketone solvent; and a step (b1) of crystallizing the first dihydroxy compound from a crystallization solution obtained by adding an alcohol solvent to the reaction solution. [2] The production method according to the above item [1], wherein the first dihydroxy compound is a dihydroxy compound represented by general formula (1'), and the ratio of the content (g / g) of the ketone solvent to the content (g / g) of the alcohol solvent relative to the total amount of the dihydroxy compound mixture in the crystallization solution (ketone solvent / alcohol solvent) is 1 or more. [3] The production method according to the above [2], wherein the dihydroxy compound represented by the general formula (1') includes 2,2'-bis(1-hydroxymethoxy)-1,1'-binaphthalene and 2,2'-bis(2-hydroxyethoxy)-1,1'-binaphthalene (BNE). [4] The production method according to the above [2] or [3], wherein the other dihydroxy compound includes at least one of a dihydroxy compound represented by the general formula (2') and a dihydroxy compound represented by the general formula (3'). [5] The production method according to the above [4], wherein the dihydroxy compound represented by the general formula (2') includes 9,9-bis[4-(2-hydroxyethoxy)-3-phenylphenyl]fluorene (BPPEF), and the dihydroxy compound represented by the general formula (3') includes 9,9-bis[6-(1-hydroxymethoxy)naphthalen-2-yl]fluorene (BNEF). [6] The method according to any one of [2] to [5] above, wherein the alcohol-based solvent is methanol. [7] The method according to [1] above, wherein the first dihydroxy compound is a dihydroxy compound represented by general formula (2'), the alcohol-based solvent is methanol, and the ratio of the content (g / g) of the ketone-based solvent to the total amount of the dihydroxy compound mixture in the crystallization solution (ketone-based solvent / alcohol-based solvent) is less than 1.[8] The manufacturing method according to the above [7], wherein the dihydroxy compound represented by the general formula (2') includes 9,9-bis[4-(2-hydroxyethoxy)-3-phenylphenyl]fluorene (BPPEF). [9] The manufacturing method according to the above [7] or [8], wherein the other dihydroxy compound includes at least one of the dihydroxy compound represented by the general formula (1') and the dihydroxy compound represented by the general formula (3').

[10] The manufacturing method according to the above [9], wherein the dihydroxy compound represented by the general formula (1') includes 2,2'-bis(1-hydroxymethoxy)-1,1'-binaphthalene or 2,2'-bis(2-hydroxyethoxy)-1,1'-binaphthalene (BNE), and the dihydroxy compound represented by the general formula (3') includes 9,9-bis[6-(1-hydroxymethoxy)naphthalen-2-yl]fluorene (BNEF).

[11] The method according to any one of the above [1] to

[10] , wherein the total content of the ketone solvent and the alcohol solvent in the crystallization solution is 1 to 20 g / g relative to the total amount of the mixture of dihydroxy compounds.

[12] The waste resin composition is a compound represented by the following general formulas (6) to (8): [In the formula, X ｇ each independently represents an alkylene group having 1 to 10 carbon atoms; ｊ , R ｋ , and R ｌ each independently represents a halogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 5 to 20 carbon atoms, a substituted or unsubstituted cycloalkoxy group having 5 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, a substituted or unsubstituted heteroaryl group having 3 to 20 carbon atoms containing one or more hetero ring atoms selected from O, N, and S, a substituted or unsubstituted aryloxy group having 6 to 20 carbon atoms, and —C≡C—R ｉ is selected from R ｉrepresents a substituted or unsubstituted aryl group having 6 to 20 carbon atoms or a heteroaryl group having 3 to 20 carbon atoms and containing one or more hetero ring atoms selected from O, N, and S; each p independently represents an integer of 0 or 1; each q, r, and s independently represents an integer of 0 to 10; and t represents an integer of 1 to 3, where q is 2 or more and two R ｊ When two R ｊ may be joined together to form a ring structure, r is 2 or more, and two R ｋ When two R ｋ may be joined together to form a ring structure, s is 2 or more, and two R ｌ When two R ｌ may be joined together to form a ring structure, R ｍ represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.]

[13] A method for producing a recycled resin, comprising polymerizing a dihydroxy compound produced by the method according to any one of [1] to

[12] above.

[0010] According to the present invention, a waste resin composition containing a synthetic resin and organic impurities can be recycled.

[0011] Hereinafter, embodiments of the present invention will be described in detail.

[0012] <Method for Producing Dihydroxy Compound> The method of the present invention provides a method for producing a dihydroxy compound from a waste resin composition, comprising: a step (a1) of treating an alkaline solution containing a waste resin composition including a resin having at least two structural units selected from the group consisting of the following general formulae (1) to (4), a ketone-based solvent, and water to obtain a reaction solution containing a mixture of dihydroxy compounds including a first dihydroxy compound selected from the group consisting of the following general formulae (1') to (4') and at least one other dihydroxy compound selected from the group consisting of the general formulae (1') to (4'), and a ketone-based solvent; and a step (b1) of adding an alcohol-based solvent to the reaction solution to obtain a crystallization solution, from which the first dihydroxy compound is crystallized.

[0013]

[0014] In the formula, ａ , X ｂ , X ｃ , X ｄ , X ｅ , and X ｆ each independently represents an alkylene group having 1 to 4 carbon atoms; ａ , R ｂ , R ｃ , R ｃｃ , R ｄ , R ｄｄ , R ｅ , R ｅｅ , R ｆ、 and R ｆｆ each independently represents a halogen atom, an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, a cycloalkyl group having 5 to 20 carbon atoms, a cycloalkoxy group having 5 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, a heteroaryl group having 3 to 20 carbon atoms containing one or more hetero ring atoms selected from O, N, and S, an aryloxy group having 6 to 20 carbon atoms, and —C≡C—R ｉ is selected from R ｉrepresents an aryl group having 6 to 20 carbon atoms or a heteroaryl group having 3 to 20 carbon atoms and containing one or more hetero ring atoms selected from O, N, and S; a, b, c, d, e, and f each independently represent an integer of 0 to 10; h, i, j, j', k, k', m, m', n, and n' each independently represent an integer of 0 to 4; R ｇ each independently represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.

[0015]

[0016] In the formula, each symbol has the same meaning as in the above general formulas (1) to (4).

[0017] According to the above-described production method, a dihydroxy compound derived from a desired synthetic resin can be produced from a waste resin composition containing a desired synthetic resin, specifically a resin having at least two structural units selected from the group consisting of general formulas (1) to (4), and organic impurities.

[0018] Specifically, the above-described production method can first suitably remove organic impurities. In step (a1), at least a portion of the desired synthetic resin is depolymerized under alkaline conditions. In this process, the organic impurities contained in the waste resin composition differ in chemical properties (ease of depolymerization in an alkaline aqueous solution) and / or physical properties after depolymerization, and therefore the organic impurities can be removed from the waste resin composition.

[0019] Furthermore, when a desired synthetic resin contains two or more types of structural units, the resulting mixture may be a mixture of two or more types of dihydroxy compounds after depolymerization. In this case, it may be difficult to separate the two or more types of dihydroxy compounds because the two or more types of dihydroxy compounds have similar structures and therefore similar physical properties. However, according to the above-mentioned production method, these dihydroxy compounds can be separated and purified, and a highly pure dihydroxy compound can be produced.

[0020] That is, according to the above-mentioned production method, a dihydroxy compound with high purity can be produced from a waste resin composition. As a result, when a resin (recycled resin) is produced using the obtained dihydroxy compound, a high-quality resin (recycled resin) can be produced. That is, the waste resin composition can be suitably recycled.

[0021] In addition, by using a ketone-based solvent in step (a1) and an alcohol-based solvent in step (b1), the above-mentioned production method can achieve one or both of the following two effects. First, the crystallization solution does not solidify during crystallization in step (b1). If the crystallization solution solidifies in step (b1), the power required to stir the crystallization solution increases, resulting in increased production costs, particularly on an industrial scale. In the present invention, the use of a combination of specific solvents can prevent or suppress solidification of the crystallization solution that may occur in step (b1), thereby reducing production costs, particularly on an industrial scale. Second, the purity of the resulting dihydroxy compound can be extremely high. As described above, the dihydroxy compound obtained by the present invention can be used to produce recycled resins. In this case, depending on the purity of the dihydroxy compound, a certain amount of impurities may be contained. These impurities may affect the polymerization reaction, preventing the production of recycled resins with the desired physical properties. As a result, further consideration may be required to optimize the polymerization reaction conditions. In contrast, the dihydroxy compound obtained by the present invention has an extremely high purity, and therefore the polymerization reaction can be easily controlled, making it possible to produce a recycled resin having desired physical properties.

[0022] In one embodiment, the production method according to the present invention may further include a step of preparing a waste resin composition. In one embodiment, the production method according to the present invention includes a step of preparing a waste resin composition, step (a1), and step (b1) in this order. Each step will be described in detail below.

[0023] [Step of Preparing a Waste Resin Composition] The production method according to the present invention may include a step of preparing a waste resin composition. In this case, the step of preparing the waste resin composition is usually carried out before the step (a1).

[0024] In one embodiment, the step of preparing the waste resin composition includes pulverizing a waste resin composition raw material to prepare the waste resin composition. Also, in one embodiment, the step of preparing the waste resin composition includes removing metals from the waste resin composition raw material. The step of preparing the waste resin composition may include both the pulverization and the metal removal. In this case, the order of pulverization and metal removal is not particularly limited, but it is preferable to perform the metal removal after pulverization because this allows for efficient metal removal.

[0025] (Waste Resin Composition Raw Material) The waste resin composition raw material is not particularly limited, but may be derived from molded products recovered after being used on the market as part of a product, defective products generated in the molding process, molded products (sprue, runner, gate, etc.) generated as ancillary to the molding process, defective products generated in the commercialization process, unused molded products that are no longer needed, etc. Among these, from the viewpoint of minimizing deterioration of the desired synthetic resin, those derived from defective products generated in the molding process, molded products (sprue, runner, gate, etc.) generated as ancillary to the molding process, and unused molded products that are no longer needed are preferred. From the viewpoint of acquisition efficiency, defective products generated in the molding process and molded products (sprue, runner, gate, etc.) generated as ancillary to the molding process are more preferred. Note that the above-mentioned molded products, etc. may be sorted, and only those containing organic impurities may be used as the waste resin composition raw material. For example, sprues may be sorted, and those that can be recycled as they are removed and used in products, and the remaining ones containing organic impurities may be used as the waste resin composition raw material. Furthermore, waste resin composition raw materials may be obtained by mixing those of different origins.

[0026] The shape of the waste resin composition raw material is not particularly limited, and examples thereof include powder, pellets, sheets, films, molded products, and the like, as well as discarded lenses, sheets, and films; defective products and burrs generated during manufacturing and / or molding processing; manufacturing waste; solids recovered from waste products using resin, and pulverized products thereof.

[0027] The longest diameter of the waste resin composition raw material is preferably 100 cm or less, more preferably 50 cm or less, and even more preferably 0.5 to 3 cm. If the longest diameter of the waste resin composition raw material is 100 cm or less, this is preferable because the energy required for pulverization is low. In this specification, the "longest diameter" means the average value of the diameters having the longest distance along the contour line of 200 randomly selected objects.

[0028] (Pulverization) The pulverization method is not particularly limited, and any of compression, impact, shear, and friction methods may be used.

[0029] Examples of crushers that can be used include coarse crushers such as jaw crushers, gyratory crushers, impact crushers, uniaxial crushers, and biaxial crushers; medium crushers such as roll crushers, edge runners, disintegrators, SAG (Semi-Autogenous Grinding) mills, crushing rolls, hammer mills, and roller mills; and fine crushers such as bead mills, ball mills, vibration ball mills, rod mills, jet mills, and planetary mills. Of these, coarse crushers are preferred, and uniaxial crushers and biaxial crushers are more preferred. Specific examples of crushers include high-power crushers 35-560, 35-720, 55-770, and 55-1050 (manufactured by Tanaka Corporation), and low-speed crushers KGA-250 and KGA-350 (manufactured by Kawata Corporation). The above-mentioned crushers may be used alone or in combination of two or more.

[0030] (Metal Removal) The method for removing metals is not particularly limited, and examples thereof include a method using magnetic force, a method using wind power, a method using a sieve, a method using specific gravity, and a method using buoyancy. Among these, a method using magnetic force (a method using a magnet, a method using a metal detector, etc.), a method using specific gravity, and a method using buoyancy (a method using salt water) are preferred. These methods may be used alone or in combination of two or more.

[0031] The metals to be removed include metals contained in plastic products, metals mixed in during the molding process, metals mixed in during the crushing process, and the like.

[0032] (Waste resin composition) The waste resin composition may be the waste resin composition raw material as it is, but is preferably one obtained by pulverizing the waste resin composition raw material, removing metals, etc. However, when pulverization and metal removal are not required in the waste resin composition raw material, it is preferable to use the waste resin composition raw material as it is as the waste resin composition. For example, when the size of the waste resin composition raw material is uniform, the longest diameter of the waste resin composition raw material is small (for example, the longest diameter is 5 cm or less), or no metal is contained, it is preferable not to perform the step of preparing the waste resin composition from the viewpoint of production costs.

[0033] The waste resin composition contains the desired synthetic resin and organic impurities. In this specification, the term "resin" refers to a resin having a weight-average molecular weight of 1,000 or more. In this specification, the term "weight-average molecular weight (Mw)" refers to the weight-average molecular weight in terms of polystyrene measured by gel permeation chromatography (GPC).

[0034] Desired Synthetic Resin The desired synthetic resin is a resin having at least two structural units selected from the group consisting of the following general formulas (1) to (4).

[0035] The resin having the above-mentioned structural units is usually a polycarbonate (PC) resin or a polyester carbonate resin, and preferably a polycarbonate resin.

[0036]

[0037] In the above formula, Xａ , X ｂ , X ｃ , X ｄ , X ｅ , and X ｆ each independently represents an alkylene group having 1 to 4 carbon atoms. Examples of the alkylene group having 1 to 4 carbon atoms include methylene, ethylene, propylene, isopropylene, butylene, isobutylene, sec-butylene, and tert-butylene. Of these, methylene and ethylene are preferred, and ethylene is more preferred.

[0038] R ａ , R ｂ , R ｃ , R ｃｃ , R ｄ , R ｄｄ , R ｅ , R ｅｅ , R ｆ、 and R ｆｆ each independently represents a halogen atom, an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, a cycloalkyl group having 5 to 20 carbon atoms, a cycloalkoxy group having 5 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, a heteroaryl group having 3 to 20 carbon atoms containing one or more hetero ring atoms selected from O, N, and S, an aryloxy group having 6 to 20 carbon atoms, and —C≡C—R ｉ is selected from.

[0039] Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

[0040] Examples of the alkyl group having 1 to 20 carbon atoms include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, an undecyl group, a dodecyl group, and an icosyl group.

[0041] Examples of the alkoxy group having 1 to 20 carbon atoms include a methoxy group, an ethoxy group, a propyloxy group, an isopropyloxy group, a butoxy group, an isobutoxy group, a sec-butoxy group, a tert-butoxy group, a pentyloxy group, a hexyloxy group, a heptyloxy group, an octyloxy group, a nonyloxy group, a decyloxy group, an undecyloxy group, a dodecyloxy group, and an icosyloxy group.

[0042] Examples of the cycloalkyl group having 5 to 20 carbon atoms include a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, a cyclododecyl group, a cyclotridecyl group, a cyclotetradecyl group, a cyclopentadecyl group, a cyclooctadecyl group, a bicyclo[2.2.1]heptyl group, and a bicyclo[2.2.2]octyl group.

[0043] Examples of the cycloalkoxy group having 5 to 20 carbon atoms include a cyclopentyloxy group, a cyclohexyloxy group, a cycloheptyloxy group, a cyclooctyloxy group, a cyclododecyloxy group, a cyclotridecyloxy group, a cyclotetradecyloxy group, a cyclopentadecyloxy group, a cyclooctadecyloxy group, a bicyclo[2.2.1]heptyloxy group, and a bicyclo[2.2.2]octyloxy group.

[0044] Examples of the aryl group having 6 to 20 carbon atoms include a phenyl group, a tolyl group, a xylyl group, a trimethylphenyl group, a tetramethylphenyl group, an ethylphenyl group, an ethylmethylphenyl group, a diethylphenyl group, a propylphenyl group, an isopropylphenyl group, an isopropylmethylphenyl group, a benzyl group, a phenethyl group, a phenylpropyl group, a naphthyl group, an anthracenyl group, a phenanthrenyl group, a naphthacenyl group, a chryserinyl group, a pyrenyl group, a biphenyl group, a terphenyl group, and a quaterphenyl group.

[0045] Examples of the heteroaryl group having 3 to 20 carbon atoms and containing one or more heterocyclic atoms selected from O, N, and S include a furanyl group, a benzofuranyl group, an isobenzofuranyl group, a pyrrolyl group, an imidazolyl group, a pyrazolyl group, a triazolyl group, a pyridyl group, a pyrazyl group, a pyrimidyl group, a pyridazyl group, a pyrrolidyl group, an indolyl group, an isoindolyl group, an indazolyl group, a quinolyl group, an isoquinolyl group, a naphthyridyl group, a quinoxalyl group, a quinazolyl group, a propanol ... Examples thereof include a teridyl group, a phenanthridyl group, an acridinyl group, a pyrimidinyl group, a phenanthrolinyl group, a phenazinyl group, a thiophenyl group, a thiopyranyl group, a benzothiophenyl group, a benzothiopyranyl group, an oxazolyl group, an isoxazolyl group, a thiazolyl group, an isothiazolyl group, a furazanyl group, an oxadiazolyl group, a dithiazolyl group, a benzoxazolyl group, a benzisoxazolyl group, a benzothiazolyl group, and a benzisothiazolyl group.

[0046] Examples of the aryloxy group having 6 to 20 carbon atoms include a phenyloxy group, a tolyloxy group, a xylyloxy group, a trimethylphenyloxy group, a tetramethylphenyloxy group, an ethylphenyloxy group, an ethylmethylphenyloxy group, a diethylphenyloxy group, a propylphenyloxy group, an isopropylphenyloxy group, an isopropylmethylphenyloxy group, a naphthyloxy group, an anthracenyloxy group, a phenanthrenyloxy group, a naphthacenyloxy group, a chryserinyloxy group, a pyrenyloxy group, a biphenyloxy group, a terphenyloxy group, and a quaterphenyloxy group.

[0047] Of these, R ａ , R ｂ , R ｃ , R ｃｃ , R ｄ , R ｄｄ , R ｅ , R ｅｅ , R ｆ、 and R ｆｆ At least one of the groups is preferably a phenyl group or a naphthyl group, and more preferably at least one of the groups is a phenyl group, a 1-naphthyl group or a 2-naphthyl group.

[0048] Rｉ represents an aryl group having 6 to 20 carbon atoms or a heteroaryl group having 3 to 20 carbon atoms and containing one or more heterocyclic atoms selected from O, N, and S. Examples of the aryl group having 6 to 20 carbon atoms and the heteroaryl group having 3 to 20 carbon atoms and containing one or more heterocyclic atoms selected from O, N, and S include those mentioned above. Among these, R ｉ is preferably a phenyl group or a naphthyl group, more preferably a phenyl group, a 1-naphthyl group or a 2-naphthyl group.

[0049] a, b, c, d, e, and f each independently represent an integer of 0 to 10. In one embodiment, a, b, c, d, e, and f each independently represent preferably an integer of 0 to 5, more preferably an integer of 0 to 3, and even more preferably an integer of 0 or 1. In another embodiment, a, b, c, d, e, and f each independently represent preferably an integer of 1 to 5, more preferably an integer of 1 to 3, and even more preferably an integer of 1 or 2.

[0050] h, i, j, j', k, k', m, m', n, and n' each independently represent an integer of 0 to 4, preferably 0 to 3, more preferably 0 to 2, even more preferably 0 or 1, and particularly preferably 0.

[0051] R ｇ Each independently represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. Examples of the alkyl group having 1 to 3 carbon atoms include a methyl group, an ethyl group, a propyl group, and an isopropyl group. ｇ are each preferably independently a hydrogen atom.

[0052] Specific examples of the structural unit represented by formula (1) include structural units derived from 2,2'-bis(1-hydroxymethoxy)-1,1'-binaphthalene, 2,2'-bis(2-hydroxyethoxy)-1,1'-binaphthalene (also referred to as "BNE"), 2,2'-bis(2-hydroxyethoxy)-6,6'-diphenyl-1,1'-binaphthalene (also referred to as "DP"), 2,2'-bis(3-hydroxypropyloxy)-1,1'-binaphthalene, 2,2'-bis(4-hydroxybutoxy)-1,1'-binaphthalene, and the like. In one embodiment, the structural unit represented by formula (1) comprises at least one structural unit derived from 2,2'-bis(2-hydroxyethoxy)-1,1'-binaphthalene (BNE) or 2,2'-bis(2-hydroxyethoxy)-6,6'-diphenyl-1,1'-binaphthalene (DP). In another embodiment, the structural unit represented by formula (1) comprises a structural unit derived from 2,2'-bis(2-hydroxyethoxy)-1,1'-binaphthalene (BNE).

[0053] Specific examples of the structural unit represented by formula (2) include structural units derived from 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene (also referred to as "BPEF"), 9,9-bis[4-(2-hydroxyethoxy)-3-methylphenyl]fluorene, 9,9-bis[4-(2-hydroxyethoxy)-3-tert-butylphenyl]fluorene, 9,9-bis[4-(2-hydroxyethoxy)-3-isopropylphenyl]fluorene, 9,9-bis[4-(2-hydroxyethoxy)-3-cyclohexylphenyl]fluorene, and 9,9-bis[4-(2-hydroxyethoxy)-3-phenylphenyl]fluorene (also referred to as "BPPEF"), etc. In one embodiment, the constitutional unit represented by formula (2) comprises at least one constitutional unit derived from a compound selected from 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene (BPEF) and 9,9-bis[4-(2-hydroxyethoxy)-3-phenylphenyl]fluorene (BPPEF). In another embodiment, the constitutional unit represented by formula (2) comprises a constitutional unit derived from 9,9-bis[4-(2-hydroxyethoxy)-3-phenylphenyl]fluorene (BPPEF).

[0054] Specific examples of the structural unit represented by formula (3) include structural units derived from 9,9-bis(hydroxy(poly)alkoxynaphthyl)fluorenes. For example, structural units derived from a compound selected from 9,9-bis[6-(1-hydroxymethoxy)naphthalen-2-yl]fluorene (also referred to as "BNEF"), 9,9-bis[6-(2-hydroxyethoxy)naphthalen-2-yl]fluorene, 9,9-bis[6-(3-hydroxypropoxy)naphthalen-2-yl]fluorene, and 9,9-bis[6-(4-hydroxybutoxy)naphthalen-2-yl]fluorene are included. In one embodiment, the structural unit represented by formula (3) includes a structural unit derived from 9,9-bis[6-(2-hydroxyethoxy)naphthalen-2-yl]fluorene (BNEF).

[0055] Specific examples of the structural unit represented by formula (4) include structural units derived from decahydro-1,4:5,8-dimethanonaphthalene diols (also referred to as "D-NDM"). For example, structural units derived from compounds selected from (decahydro-1,4:5,8-dimethanonaphthalene-2,6-diyl)dimethanol, (decahydro-1,4:5,8-dimethanonaphthalene-2,7-diyl)dimethanol, (2-methyldecahydro-1,4:5,8-dimethanonaphthalene-2,6-diyl)dimethanol, (2-methyldecahydro-1,4:5,8-dimethanonaphthalene-2,7-diyl)dimethanol, (2-ethyldecahydro-1,4:5,8-dimethanonaphthalene-2,6-diyl)dimethanol, and (2-ethyldecahydro-1,4:5,8-dimethanonaphthalene-2,7-diyl)dimethanol.

[0056] The desired synthetic resin contains at least two of the above-mentioned structural units. In this case, the structural units may contain two or more structural units represented by the same general formula (for example, two structural units represented by general formula (1)), or may contain two or more structural units represented by different general formulas (for example, one or more structural units represented by general formula (1) and one or more structural units represented by general formula (2)). In addition, the above-mentioned structural units may be combined with structural units of other polycarbonate resins, or may be combined with structural units of other resins (polyolefin resins, polyester resins), etc.

[0057] In one embodiment, the desired synthetic resin is preferably a resin having structural units of general formulas (1) to (3), more preferably containing structural units derived from at least one of BNE and DP, at least one of BPEF and BPPEF, and BNEF, still more preferably containing structural units derived from at least one of BNE, BPEF, and BPPEF, and BNEF, and particularly preferably containing structural units derived from BNE, BPPEF, and BNEF.

[0058] When the desired synthetic resin is a resin having structural units of the general formulas (1) to (3), the molar ratio of the structural units of the general formula (1) (e.g., structural units derived from BNE) and the structural units of the general formula (2) (e.g., structural units derived from BPPEF) (general formula (1) / general formula (2)) is preferably 1.0 to 5.0, more preferably 1.0 to 4.0, 1.5 to 3.0, and even more preferably 2.0 to 3.0. Furthermore, when the desired synthetic resin is a resin having structural units of the general formulas (1) to (3), the molar ratio of the structural units of the general formula (1) (e.g., structural units derived from BNE) and the structural units of the general formula (3) (e.g., structural units derived from BNEF) (general formula (1) / general formula (3)) is preferably 1.0 to 5.0, more preferably 1.0 to 4.0, 1.5 to 3.0, and even more preferably 1.5 to 2.0. Furthermore, when the desired synthetic resin is a resin having structural units of general formulas (1) to (3), the molar ratio (general formula (2) / general formula (3)) of the structural unit of general formula (2) (for example, a structural unit derived from BPPEF) to the structural unit of general formula (3) (for example, a structural unit derived from BNEF) is preferably 0.5 to 1.5, more preferably 0.5 to 1.0, or 1.0 to 1.5, and even more preferably 0.6 to 0.8, or 1.1 to 1.4.

[0059] The weight average molecular weight (Mw) of the desired synthetic resin is not particularly limited, but is preferably 10,000 to 70,000, and more preferably 15,000 to 50,000. If the weight average molecular weight (Mw) of the desired synthetic resin is 10,000 or more, it is preferable because it can maintain appropriate strength as a molded product, such as a resin for an optical lens. On the other hand, if the weight average molecular weight (Mw) of the desired synthetic resin is 70,000 or less, it is preferable because it can maintain appropriate fluidity during resin molding and improve moldability.

[0060] The content of the desired synthetic resin in the waste resin composition is preferably 80% by mass or more, and more preferably 80 to 99% by mass, based on the mass of the waste resin composition. When the content of the desired synthetic resin is 80% by mass or more, it is preferable because the recycling efficiency is high.

[0061] Organic Impurities Examples of organic impurities include impurity resins and impurity compounds.

[0062] The impurity resins include thermoplastic resins other than the desired synthetic resin.

[0063] The thermoplastic resin is not particularly limited, and examples thereof include polyolefin resins (polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), polystyrene (PS), polyvinyl acetate (PVAc), polytetrafluoroethylene (PTFE), etc.), polyurethane (PU) resins, acrylic resins, polyester resins (polyethylene terephthalate (PET), polybutylene terephthalate (PBT)), polyamide (PA) resins, polyacetal resins, cyclic polyolefins (cycloolefin polymers), polyphenylene sulfide (PPS) resins, polysulfone resins, polyethersulfone resins, liquid crystal polymers (LCPs), polyether ether ketone (PEEK) resins, polyamide imide (PAI) resins, and copolymers of structural units of these resins (acrylonitrile-styrene copolymer resin (AS resin), acrylonitrile-butylene-styrene copolymer resin (ABS resin), etc.).

[0064] Among these, the waste resin composition preferably contains an impurity resin having at least one structural unit selected from the group consisting of the following general formulas (6) to (8): The impurity resin having the structural unit is usually a cyclic polyolefin.

[0065]

[0066] In the above formula, X ｇ each independently represents an alkylene group having 1 to 10 carbon atoms. Examples of the alkylene group having 1 to 10 carbon atoms include methylene, ethylene, propylene, isopropylene, butylene, isobutylene, sec-butylene, tert-butylene, and pentylene. Of these, methylene, ethylene, propylene, butylene, isobutylene, and sec-butylene are preferred, and methylene, ethylene, and propylene are more preferred.

[0067] R ｊ , Rｋ , and R ｌ each independently represents a halogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 5 to 20 carbon atoms, a substituted or unsubstituted cycloalkoxy group having 5 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, a substituted or unsubstituted heteroaryl group having 3 to 20 carbon atoms containing one or more hetero ring atoms selected from O, N, and S, a substituted or unsubstituted aryloxy group having 6 to 20 carbon atoms, and —C≡C—R ｉ The R ｊ , R ｋ , and R ｌ As the above, X ａ , X ｂ , X ｃ , X ｄ , X ｅ , and X ｆ The same can be mentioned.

[0068] However, R ｊ , R ｋ , and R ｌ may have a substituent. The substituent is not particularly limited, but examples thereof include a halogen atom, an alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 5 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a cycloalkyloxy group having 5 to 10 carbon atoms, an alkyloxycarbonyl group having 2 to 10 carbon atoms, a cycloalkyloxycarbonyl group having 5 to 10 carbon atoms, an aryloxycarbonyl group having 7 to 15 carbon atoms, an alkylcarbonyloxy group having 2 to 10 carbon atoms, a cycloalkylcarbonyloxy group having 5 to 10 carbon atoms, an arylcarbonyloxy group having 7 to 15 carbon atoms, a hydroxyalkylcarbonyl group having 2 to 10 carbon atoms, a glycidyloxycarbonyl group, a hydroxy group, a carboxy group, a cyano group, and an amide group having 1 to 10 carbon atoms.

[0069] Examples of the alkyl group having 1 to 10 carbon atoms include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, and a pentyl group.

[0070] Examples of the cycloalkyl group having 5 to 10 carbon atoms include a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a bicyclo[2.2.1]heptyl group, and a bicyclo[2.2.2]octyl group.

[0071] Examples of the alkoxy group having 1 to 10 carbon atoms include a methoxy group, an ethoxy group, a propyloxy group, an isopropyloxy group, a butoxy group, an isobutoxy group, a sec-butoxy group, a tert-butoxy group, and a pentyloxy group.

[0072] Examples of the cycloalkyloxy group having 5 to 10 carbon atoms include a cyclopentyloxy group, a cyclohexyloxy group, a bicyclo[2.2.1]heptyloxy group, and a bicyclo[2.2.2]octyloxy group.

[0073] Examples of the alkyloxycarbonyl group having 2 to 10 carbon atoms include a methyloxycarbonyl group, an ethyloxycarbonyl group, a propyloxycarbonyl group, an isopropyloxycarbonyl group, a butyloxycarbonyl group, an isobutyloxycarbonyl group, a sec-butyloxycarbonyl group, and a tert-butyloxycarbonyl group.

[0074] Examples of the cycloalkyloxycarbonyl group having 5 to 10 carbon atoms include a cyclopentyloxycarbonyl group, a cyclohexyloxycarbonyl group, a bicyclo[2.2.1]heptyloxycarbonyl group, and a bicyclo[2.2.2]octyloxycarbonyl group.

[0075] Examples of the aryloxycarbonyl group having 7 to 15 carbon atoms include a phenyloxycarbonyl group, a tolyloxycarbonyl group, a xylyloxycarbonyl group, a trimethylphenyloxycarbonyl group, a tetramethylphenyloxycarbonyl group, an ethylphenyloxycarbonyl group, an ethylmethylphenyloxycarbonyl group, a diethylphenyloxycarbonyl group, and a naphthyloxycarbonyl group.

[0076] Examples of the alkylcarbonyloxy group having 2 to 10 carbon atoms include a methylcarbonyloxy group, an ethylcarbonyloxy group, a propylcarbonyloxy group, an isopropylcarbonyloxy group, and a butylcarbonyloxy group.

[0077] Examples of the cycloalkylcarbonyloxy group having 5 to 10 carbon atoms include a cyclopentylcarbonyloxy group, a cyclohexylcarbonyloxy group, a bicyclo[2.2.1]heptylcarbonyloxy group, and a bicyclo[2.2.2]octylcarbonyloxy group.

[0078] Examples of the arylcarbonyloxy group having 7 to 15 carbon atoms include a phenylcarbonyloxy group, a tolylcarbonyloxy group, a xylylcarbonyloxy group, a trimethylphenylcarbonyloxy group, a tetramethylphenylcarbonyloxy group, an ethylphenylcarbonyloxy group, an ethylmethylphenylcarbonyloxy group, a diethylphenylcarbonyloxy group, and a naphthylcarbonyloxy group.

[0079] Examples of the hydroxyalkylcarbonyl group having 2 to 10 carbon atoms include a hydroxymethylcarbonyl group, a hydroxyethylcarbonyl group, and a hydroxypropylcarbonyl group.

[0080] Examples of the amide group having 1 to 10 carbon atoms include a methylaminocarbonyl group, an ethylaminocarbonyl group, a dimethylaminocarbonyl group, and an acetylamino group.

[0081] The above-mentioned substituents may be present alone or in combination of two or more kinds.

[0082] R ｉ represents an aryl group having 6 to 20 carbon atoms or a heteroaryl group having 3 to 20 carbon atoms and containing one or more hetero ring atoms selected from O, N, and S. ｉ is the same as above.

[0083] Each p independently represents an integer of 0 or 1.

[0084] q, r, and s each independently represent an integer of 0 to 10, preferably 0 to 5, and more preferably 0 to 3.

[0085] t represents an integer of 1 to 3, preferably 1 or 2.

[0086] where q is 2 or more and two R ｊ When two R ｊ may be joined together to form a ring structure. For example, when q is 2 and two R ｊ are both substituted or unsubstituted alkyl groups, the general formula (6) becomes the following formula (6-1), where q is 2 and two R ｊ When is a substituted or unsubstituted alkyl and a substituted or unsubstituted cycloalkyl, general formula (6) can be the following formula (6-2), (6-3), or (6-4).

[0087]

[0088] In the above formula, X ｇ and p is as defined above.

[0089] R ｎ is the above-mentioned substituent, and specific examples thereof include a halogen atom, an alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 5 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a cycloalkyloxy group having 5 to 10 carbon atoms, an alkyloxycarbonyl group having 2 to 10 carbon atoms, a cycloalkyloxycarbonyl group having 5 to 10 carbon atoms, an aryloxycarbonyl group having 7 to 15 carbon atoms, an alkylcarbonyloxy group having 2 to 10 carbon atoms, a cycloalkylcarbonyloxy group having 5 to 10 carbon atoms, an arylcarbonyloxy group having 7 to 15 carbon atoms, a hydroxyalkylcarbonyl group having 2 to 10 carbon atoms, a glycidyloxycarbonyl group, a hydroxy group, a carboxy group, a cyano group, and an amide group having 1 to 10 carbon atoms.

[0090] Although z is not particularly limited, it is preferably 0 to 6, more preferably 0 to 3, and even more preferably 0 or 1.

[0091] u represents an integer of 1 to 3, preferably 1 or 2.

[0092] In addition, r is 2 or more, and two R ｋ When two R ｋ may be joined together to form a ring structure. For example, when r is 2 and two R ｋ are both substituted or unsubstituted alkyl groups, the general formula (7) becomes the following formula (7-1) or (7-2), where r is 2 and the two R ｋ When is a substituted or unsubstituted alkyl and a substituted or unsubstituted cycloalkyl, general formula (7) can be the following formula (7-3).

[0093]

[0094] In the above formula, X ｇ , p, R ｎ , z, and u are as defined above.

[0095] Furthermore, s is 2 or more, and two R ｌ When two R ｌ may be joined together to form a ring structure. For example, when s is 2 and two R ｌ are both substituted or unsubstituted alkyl groups, the general formula (8) becomes the following formula (8-1) or (8-2), where s is 2 and the two R ｌ When is a substituted or unsubstituted alkyl and a substituted or unsubstituted cycloalkyl, general formula (8) can be the following formula (8-3) or (8-4).

[0096]

[0097] In the above formula, X ｇ , p, R ｎ , z, and u are as defined above.

[0098] R ｍ represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. The alkyl group having 1 to 3 carbon atoms is not particularly limited, but examples thereof include a methyl group, an ethyl group, a propyl group, and an isopropyl group.

[0099] Specific examples of impurity resins include those containing at least one selected from the group consisting of structural units represented by the following formulas 1 to 8.

[0100]

[0101] The above-mentioned structural units may be contained alone or in combination of two or more in the impurity resin. In addition, the above-mentioned structural units may be combined with structural units of other cyclic polyolefins, or with structural units of other resins (polyolefin resins, polyester resins), etc.

[0102] The weight average molecular weight (Mw) of the impurity resin is not particularly limited, but is preferably 1,000 to 3,000,000, more preferably 10,000 to 3,000,000, even more preferably 20,000 to 1,000,000, and particularly preferably 30,000 to 500,000. A weight average molecular weight (Mw) of the impurity resin of 1,000 or more is preferable because separation is facilitated. On the other hand, a weight average molecular weight (Mw) of the impurity resin of 3,000,000 or less is preferable because it is less likely to become a source of gel impurities when a trace amount of impurity resin is contaminated.

[0103] The content of impurity resins in the waste resin composition is preferably 50% by mass or less, more preferably 0.001 to 50% by mass, even more preferably 0.01 to 30% by mass, and particularly preferably 0.1 to 20% by mass, based on the total mass of the waste resin composition. A content of impurity resins of 50% by mass or less is preferred because it increases efficiency.

[0104] The impurity compounds are not particularly limited, but include the above-mentioned impurity resin monomers, dimers, copolymers, oligomers, aryl alcohols such as phenol, carbonate diesters such as diphenyl carbonate, modified synthetic resin raw material monomers of desired synthetic resins such as those represented by the following formulas (A-1) and (A-2), and modified synthetic resins having partial structures represented by the following formulas (B-1) and (B-2). In this specification, "impurity compounds" refers to organic compound impurities having a weight-average molecular weight of less than 1000. Therefore, when the weight-average molecular weight of the recycled modified resin is 1000 or more, the desired modified synthetic resin is classified as an impurity resin.

[0105]

[0106] In the above formulas (B-1) and (B-2), "*" indicates the bonding site to the polymer chain.

[0107] Shape of Waste Resin Composition The shape of the waste resin composition is not particularly limited, and examples thereof include powder, granules, rods, and the like.

[0108] The longest diameter of the waste resin composition is preferably 5 cm or less, more preferably 3 cm or less, even more preferably 0.001 to 3 cm, particularly preferably 0.01 to 2 cm, and extremely preferably 0.1 to 1 cm. A longest diameter of the waste resin composition of 5 cm or less is preferred from the viewpoints of ease of transportation, ease of depolymerization, etc.

[0109] [Step (a1)] Step (a1) is a step of treating an alkaline solution containing a waste resin composition containing a resin having at least two structural units selected from the group consisting of the above general formulae (1) to (4), a ketone-based solvent, and water, to obtain a reaction solution containing a mixture of dihydroxy compounds including a first dihydroxy compound selected from the group consisting of the following general formulae (1') to (4') and at least one other dihydroxy compound selected from the group consisting of the above general formulae (1') to (4'), and a ketone-based solvent:

[0110] (Alkaline Solution) The alkaline solution contains a waste resin composition, a ketone-based solvent, and water. The alkaline solution may further contain other substances such as metal oxides.

[0111] The waste resin composition contains a resin having at least two structural units selected from the group consisting of the above general formulas (1) to (4), and may further contain organic impurities.

[0112] The resin is a resin having at least two structural units selected from the group consisting of general formulas (1) to (4). Therefore, the resin is usually a polycarbonate resin.

[0113] Specific examples of the structural units represented by general formulas (1) to (4) are as described above.

[0114] The resin may further contain other structural units. Examples of such structural units include, but are not limited to, structural units derived from olefins and structural units derived from esters. The resin may contain such other structural units alone or in combination of two or more.

[0115] The above-mentioned resins may be contained alone in the waste resin composition, or two or more kinds may be mixed and contained.

[0116] The weight average molecular weight (Mw) of the resin is not particularly limited, but is preferably 10,000 to 70,000, and more preferably 15,000 to 50,000. If the weight average molecular weight (Mw) of the resin is 10,000 or more, it is preferable because it can maintain appropriate strength as a molded product, such as a resin for an optical lens. On the other hand, if the weight average molecular weight (Mw) of the resin is 70,000 or less, it is preferable because it can maintain appropriate fluidity during resin molding and improve moldability.

[0117] The content of the resin in the waste resin composition is preferably 80% by mass or more, more preferably 80 to 99% by mass, based on the mass of the waste resin composition. When the content of the resin is 80% by mass or more, efficiency is high, which is preferable.

[0118] Organic impurities include impurity resins, impurity compounds, etc. The impurity resins and impurity compounds are as described above.

[0119] Among these, from the viewpoint of the large difference in chemical properties between the impurity resin and the polycarbonate resin (large difference in ease of depolymerization in an alkaline aqueous solution), the impurity resin is preferably a polyolefin resin or a cyclic polyolefin, and more preferably a cyclic polyolefin.

[0120] Ketone-based solvents Ketone-based solvents have functions such as accelerating depolymerization and dissolving the dihydroxy compound obtained by depolymerization.

[0121] The ketone solvent is not particularly limited, but examples thereof include aliphatic ketone solvents and aromatic ketone solvents.

[0122] Examples of the aliphatic ketone solvent include acetone, methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), diisobutyl ketone (DIBK), 3-pentanone, 2-hexanone, 2-heptanone, and cyclohexanone.

[0123] Examples of aromatic ketone solvents include acetophenone.

[0124] Among these, the ketone solvent preferably contains an aliphatic ketone solvent, more preferably contains at least one selected from the group consisting of acetone, methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), and diisobutyl ketone (DIBK), further preferably contains acetone and / or methyl ethyl ketone (MEK), and particularly preferably contains methyl ethyl ketone (MEK) from the viewpoint of improving the yield and purity. The above-mentioned reaction solvents may be used alone or in combination of two or more.

[0125] The amount of ketone-based solvent used is not particularly limited, but is preferably 30 to 2000 parts by mass, more preferably 40 to 1500 parts by mass, more preferably 50 to 1000 parts by mass, 90 to 1000 parts by mass, 100 to 1000 parts by mass, 50 to 800 parts by mass, 90 to 800 parts by mass, 100 to 800 parts by mass, 300 to 800 parts by mass, 50 to 500 parts by mass, 90 to 500 parts by mass, 100 to 500 parts by mass, and 100 to 300 parts by mass are even more preferred. When the amount of ketone-based solvent used is 30 parts by mass or more, the organic components of the waste resin composition are sufficiently dissolved in the reaction solvent, which increases the reaction efficiency. On the other hand, when the amount of ketone-based solvent used is 2000 parts by mass or less, it is preferable because the reaction time is shortened.

[0126] Water Water has the function of promoting depolymerization.

[0127] The amount of water used is not particularly limited, but is preferably 10 to 2,000 parts by mass, more preferably 20 to 500 parts by mass, even more preferably 30 to 300 parts by mass, and particularly preferably 50 to 300 parts by mass, or 100 to 300 parts by mass, relative to 100 parts by mass of the waste resin composition.

[0128] Metal Oxide The metal oxide has the function of adjusting the reaction solution to alkaline and promoting depolymerization.

[0129] The metal oxide is not particularly limited, but examples thereof include alkali metals such as sodium hydroxide, potassium hydroxide, and rubidium hydroxide; and alkaline earth metals such as calcium hydroxide and barium hydroxide. Among these, the metal oxide is preferably an alkali metal, more preferably sodium hydroxide or potassium hydroxide, and even more preferably potassium hydroxide. These metal oxides may be used alone or in combination of two or more.

[0130] The amount of the metal oxide used is not particularly limited, but is preferably 1.5 to 10 mol, more preferably 2 to 8 mol, and even more preferably 2 to 4 mol, per mol of carbonate bond in the polycarbonate resin. A metal oxide used in an amount of 1.5 mol or more is preferred because depolymerization is sufficiently carried out. On the other hand, a metal oxide used in an amount of 10 mol or less is preferred because production costs are reduced.

[0131] The concentration of the metal oxide in the alkaline aqueous solution is preferably 10 to 60% by mass, more preferably 15 to 55% by mass, and even more preferably 20 to 50% by mass, based on the total mass of the alkaline aqueous solution. A metal oxide concentration of 10% by mass or more is preferred because it increases the depolymerization reaction rate. On the other hand, a metal oxide concentration of 60% by mass or less is preferred because it prevents the alkaline aqueous solution from becoming a slurry and facilitates the reaction.

[0132] (Treatment) By treating the alkaline solution, a reaction solution containing a mixture of dihydroxy compounds including a first dihydroxy compound selected from the group consisting of general formulas (1') to (4') and at least one other dihydroxy compound selected from the group consisting of general formulas (1') to (4') and a ketone solvent can be obtained.

[0133] The organic impurities contained in the waste resin composition have different chemical properties during depolymerization compared to the above-mentioned resins. Therefore, the organic impurities either do not react, are depolymerized earlier than the above-mentioned resins, or are depolymerized later than the above-mentioned resins. For example, organic impurities such as polyolefin resins and cyclic polyolefins do not usually react under basic conditions, so only the above-mentioned resins are depolymerized and can be easily removed. Even if the organic impurities are depolymerized, the depolymerized products of the organic impurities usually have a different polarity from the dihydroxy compounds and can be easily removed.

[0134] As described above, the desired resin has at least two structural units selected from the group consisting of general formulas (1) to (4). Therefore, by treating the desired resin with an alkaline solution, a mixture of at least two dihydroxy compounds is obtained. Mixtures of dihydroxy compounds may have similar physical properties due to their similar structures, making isolation and purification difficult. As a result, the purity of the resulting dihydroxy compound may be low, which may limit recycling. In contrast, by performing the step (b1) described below, a highly pure dihydroxy compound can be produced. The "first dihydroxy compound" refers to a dihydroxy compound intended for isolation and purification in step (b1), and the "other dihydroxy compounds" refer to dihydroxy compounds not intended for isolation and purification in step (b1).

[0135] The treatment temperature (depolymerization reaction temperature) is not particularly limited, but is preferably 120° C. or lower, more preferably 100° C. or lower, and even more preferably 30 to 90° C. A treatment temperature of 120° C. or lower is preferred because side reactions can be prevented.

[0136] The solution obtained after the treatment (depolymerization) can be purified appropriately by washing, extraction, or the like to obtain a reaction solution. The solution obtained after the treatment (depolymerization) usually contains an organic phase derived from the ketone-based solvent and an aqueous phase derived from water. In this case, the mixture of dihydroxy compounds obtained by depolymerization may be contained in the organic phase. For this reason, it is preferable to remove the aqueous phase derived from water from the solution obtained after the treatment (depolymerization) by liquid-liquid extraction or the like.

[0137] Furthermore, if the organic impurities and depolymerized products thereof contained in the resulting reaction solution have physical properties different from those of the dihydroxy compound, they can be removed by appropriate purification at this stage. In this case, the reaction solution and crystallization solution described below contain no or almost no organic impurities and depolymerized products thereof.

[0138] (Reaction Solution) The reaction solution contains a mixture of dihydroxy compounds and a ketone solvent. The reaction solution may further contain organic impurities, depolymerized products thereof, and the like.

[0139] The mixture of dihydroxy compounds includes a first dihydroxy compound selected from the group consisting of the above general formulas (1') to (4') and at least one other dihydroxy compound selected from the group consisting of the above general formulas (1') to (4').

[0140] First Dihydroxy Compound The first dihydroxy compound is a dihydroxy compound intended to be isolated and purified in step (b1).

[0141] The first dihydroxy compound is not particularly limited, but is preferably a dihydroxy compound selected from the group consisting of general formulas (1') to (3'). In one embodiment, the first dihydroxy compound is preferably a dihydroxy compound of general formula (1'), more preferably DP or BNE, and even more preferably BNE. In another embodiment, the first dihydroxy compound is preferably a dihydroxy compound of general formula (2'), more preferably BPEF or BPPEF, and even more preferably BPPEF.

[0142] Other dihydroxy compounds: The other dihydroxy compounds are dihydroxy compounds that are not intended to be isolated or purified in step (b1). In one embodiment, the other dihydroxy compounds preferably include a dihydroxy compound of general formula (2') and / or a dihydroxy compound of general formula (3'), more preferably a dihydroxy compound of general formula (2') and a dihydroxy compound of general formula (3'), even more preferably at least one of BPEF and BPPEF, and BNEF, and particularly preferably BPPEF and BNEF. In another embodiment, the other dihydroxy compounds preferably include a dihydroxy compound of general formula (1') and / or a dihydroxy compound of general formula (3'), more preferably a dihydroxy compound of general formula (1') and a dihydroxy compound of general formula (3'), even more preferably at least one of DP and BNE, and BNEF, and particularly preferably BNE and BNEF.

[0143] The ketone-based solvent may be any of those described above. The content of the ketone-based solvent can be adjusted by distilling off the solvent or the like in a treatment after depolymerization. This allows the content of the ketone-based solvent in the crystallization solution described below to be adjusted.

[0144] The reaction solution of organic impurities and depolymerized products thereof may contain organic impurities and depolymerized products thereof.

[0145] The organic impurities are as described above. The organic impurities have a molecular weight and polarity that are significantly different from those of the first hydroxy compound, and therefore can be easily removed in the step (b1) described below.

[0146] The depolymerized products of organic impurities are not particularly limited, and examples thereof include monomers, oligomers, and the like obtained by depolymerization of organic impurities. For example, when a polyester resin is included as an organic impurity, alcohols and carboxylic acids may be obtained by depolymerization. These depolymerized products have polarities significantly different from those of dihydroxy compounds, and therefore can be easily removed in step (b1) described below.

[0147] [Step (b1)] Step (b1) is a step of crystallizing the first dihydroxy compound from a crystallization solution obtained by adding an alcohol-based solvent to the reaction solution obtained in step (a1).

[0148] (Crystallization Solution) The crystallization solution is obtained by adding an alcohol-based solvent to the reaction solution obtained in step (a1). Specifically, the crystallization solution contains the first dihydroxy compound derived from the reaction solution, other dihydroxy compounds, a ketone-based solvent, and an alcohol-based solvent. In addition, the crystallization solution may further contain seed crystals, organic impurities and depolymerized products thereof, etc.

[0149] First Dihydroxy Compound The first dihydroxy compound is obtained by depolymerization of a desired resin (usually a polycarbonate resin) and is a dihydroxy compound intended for isolation and purification. The first dihydroxy compound is a dihydroxy compound selected from the group consisting of general formulas (1') to (4'), and preferably a dihydroxy compound selected from the group consisting of general formulas (1') to (3'). In one embodiment, the first dihydroxy compound is preferably a dihydroxy compound of general formula (1'), more preferably DP or BNE, and even more preferably BNE. In another embodiment, the first dihydroxy compound is preferably a dihydroxy compound of general formula (2'), more preferably BPEF or BPPEF, and even more preferably BPPEF. Note that there is usually only one first dihydroxy compound.

[0150] The molar content of the first dihydroxy compound (first dihydroxy compound (mol) / dihydroxy compound mixture (mol)) in the dihydroxy compound mixture (mixture of first dihydroxy compound and other dihydroxy compounds) is preferably 30 mol% or more, preferably 30 to 95 mol%, more preferably 40 to 80 mol%, and particularly preferably 40 to 75 mol%, 50 to 75 mol%, 40 to 70 mol%, 50 to 70 mol%, 40 to 65 mol%, or 50 to 65 mol%. A molar content of the first dihydroxy compound of 30 mol% or more is preferred from the viewpoints of being able to produce a high-purity dihydroxy compound and being excellent in production costs.

[0151] The content of the first dihydroxy compound in the crystallization solution is preferably 1 to 35% by mass, more preferably 5 to 30% by mass, even more preferably 5 to 25% by mass, and particularly preferably 10 to 25% by mass, based on the total mass of the crystallization solution.

[0152] Other dihydroxy compounds are dihydroxy compounds obtained by depolymerization of a desired resin (usually a polycarbonate resin) and are not intended to be isolated or purified. The other dihydroxy compounds may be one type or two or more types.

[0153] The molar content of the other dihydroxy compounds (other dihydroxy compounds (moles) / dihydroxy compound mixture (moles)) in the mixture of dihydroxy compounds (mixture of first dihydroxy compound and other dihydroxy compounds) is preferably 70 mol% or less, preferably 5 to 70 mol%, more preferably 20 to 60 mol%, and particularly preferably 25 mol% or more but less than 50 mol%. A molar content of the first dihydroxy compound of 70 mol% or less is preferred from the viewpoints of being able to produce a dihydroxy compound of high purity and being excellent in production costs. When two or more types of other dihydroxy compounds are used, it is preferable that the total molar content thereof be within the above range.

[0154] The content of the other dihydroxy compound in the crystallization solution is preferably 1 to 35 mass %, more preferably 5 to 30 mass %, even more preferably 5 to 25 mass %, and particularly preferably 10 to 25 mass %, based on the total mass of the crystallization solution. When two or more kinds of other dihydroxy compounds are used, the total content thereof is preferably within the above range.

[0155] The ketone-based solvent may be any of those described above, and generally dissolves the first dihydroxy compound and other dihydroxy compounds.

[0156] The content of the ketone solvent in the crystallization solution is preferably 0.1 to 10 g / g, more preferably 0.5 to 7.5 g / g, and even more preferably 0.75 to 5 g / g, relative to the total amount of the dihydroxy compound mixture. A ketone solvent content within the above range is preferred because a highly pure dihydroxy compound (first dihydroxy compound) can be obtained by crystallization. The content of the ketone solvent in the crystallization solution can be adjusted by, for example, distilling off the solvent after depolymerization. The "total amount of the dihydroxy compound mixture" refers to the total amount of the first dihydroxy compound and the other dihydroxy compounds.

[0157] Alcohol-based solvents are solvents in which the solubility of dihydroxy compounds is relatively low compared to the solubility of dihydroxy compounds in ketone-based solvents, and as a result, the dihydroxy compounds can be crystallized from a crystallization solution obtained by adding the alcohol-based solvent to a reaction solution containing a ketone-based solvent.

[0158] The alcohol solvent is not particularly limited, but examples thereof include aliphatic alcohol solvents and aromatic alcohol solvents.

[0159] Examples of the aliphatic alcohol solvent include methanol, ethanol, isopropyl alcohol, 1-butanol, 2-butanol, tert-butanol, 1-propanol, 2-propanol, 1-pentanol, 2-pentanol, 2-methyl-2-propanol, 2-ethylhexanol, cyclohexanol, and allyl alcohol.

[0160] Examples of aromatic alcohol solvents include phenol, benzyl alcohol, and furfuryl alcohol.

[0161] The alcohol-based solvent preferably contains an aliphatic alcohol-based solvent, more preferably contains at least one selected from the group consisting of methanol, ethanol, isopropyl alcohol, 1-butanol, 2-butanol, and tert-butanol, further preferably contains methanol and / or ethanol, and particularly preferably contains methanol.

[0162] The content of the alcohol-based solvent in the crystallization solution is preferably 0.001 to 20 g / g, more preferably 0.01 to 15 g / g, based on the total amount of the mixture of dihydroxy compounds, and more preferably 0.1 to 10 g / g, 0.4 to 10 g / g, 0.6 to 10 g / g, 2 to 10 g / g, 5 to 10 g / g, 5 to 10 g / g, 0.1 to 5 g / g, 0.4 to 5 g / g, 0.6 to 5 g / g, 2 to 5 g / g, 0.1 to 5 g / g, 0.4 to 2 g / g, 0.6 to 2 g / g, 0.1 to 0.6 g / g, 0.4 to 0.6 g / g, and even more preferably 0.1 to 0.4 g / g. When the content of the alcohol-based solvent is within the above range, a highly pure dihydroxy compound (first dihydroxy compound) can be obtained by crystallization, which is preferable.

[0163] The total content of the ketone solvent and the alcohol solvent in the crystallization solution is preferably 0.5 to 20 g / g, more preferably 1 to 20 g / g, and even more preferably 1 to 10 g / g, relative to the total amount of the mixture of dihydroxy compounds, and particularly preferably 1 to 8 g / g, 1.1 to 8 g / g, 1.8 to 8 g / g, 3 to 8 g / g, 4 to 8 g / g, 1 to 4 g / g, 1.1 to 4 g / g, 1.8 to 4 g / g, 3 to 4 g / g, 1 to 3 g / g, 1.1 to 3 g / g, 1.8 to 3 g / g, 1 to 1.8 g / g, 1.1 to 1.8 g / g, or 1 to 1.1 g / g. A total content of the ketone solvent and the alcohol solvent of 0.5 g / g or more is preferred because the purity of the first dihydroxy compound can be increased. On the other hand, if the total content of the ketone solvent and the alcohol solvent is 20 g / g or less, the yield can be increased, which is preferable.

[0164] The ratio of the ketone solvent content (g / g) to the alcohol solvent content (g / g) in the crystallization solution (ketone solvent / alcohol solvent) is preferably 0.1 to 1000, more preferably 0.1 to 120, and even more preferably 0.1 to 10. When the ratio (ketone solvent / alcohol solvent) is in the above range, the purity of the first dihydroxy compound can be increased, which is preferable.

[0165] The seed crystallization solution may further contain seed crystals. Addition of the seed crystals can promote crystallization of the first dihydroxy compound. The seed crystals are usually added to the reaction solution before, simultaneously with, or after addition of the alcohol-based solvent.

[0166] The seed crystals are not particularly limited, and examples thereof include crystals of the first dihydroxy compound, crystals of other dihydroxy compounds, and diphenol compounds that can be used as raw materials for polycarbonates, such as bisphenol A. Of these, the seed crystals are preferably crystals of the first dihydroxy compound, from the viewpoint of increasing the purity of the dihydroxy compound (first dihydroxy compound) obtained by crystallization. The above-mentioned seed crystals may be used alone or in combination of two or more types.

[0167] The form of the seed crystal is not particularly limited, but is preferably a crystalline solvate. In this case, the compound that forms the crystalline solvate is not particularly limited, but is preferably a dihydroxy compound selected from the group consisting of general formulas (1') to (3'). In one embodiment, the compound that forms the crystalline solvate is preferably a dihydroxy compound represented by general formula (1'), more preferably DP and / or BNE, and even more preferably BNE. In another embodiment, the compound that forms the crystalline solvate is preferably a dihydroxy compound represented by general formula (2'), more preferably BPEF and / or BPPEF, and even more preferably BPPEF. Furthermore, the solvent that constitutes the solvate is not particularly limited, but is preferably the above-mentioned ketone solvents or the above-mentioned alcohol solvents, and more preferably acetone, methyl ethyl ketone, methanol, or ethanol. Furthermore, the content of the solvent in the crystalline solvate is preferably 0.3 to 1.5 moles per mole of the compound that forms the crystalline solvate. By using seed crystals in the form of a crystalline solvate, a dihydroxy compound with high purity can be produced. In this specification, the term "crystalline solvate" refers to a crystalline form that contains a solvent inside the crystal lattice of a seed crystal.

[0168] The ratio of the mode diameter to the median diameter of the seed crystals (mode diameter / median diameter) is preferably 2.0 or less, more preferably 1.0 to 1.6. A ratio (mode diameter / median diameter) of 2.0 or less is preferred because the resulting dihydroxy compound can be in the form of highly pure, easily handled, bulk crystals. In this specification, "mode diameter" refers to the most frequent diameter exhibiting the highest frequency value, and is measured by particle size measurement using a laser diffraction method. Furthermore, "median diameter" refers to the particle size at 50% of the cumulative value in a cumulative particle size distribution, and is measured by particle size measurement using a laser diffraction method.

[0169] The aspect ratio of the seed crystal is preferably 1 to 8, and more preferably 1 to 3. In this specification, "aspect ratio" refers to the ratio (L / W) of the maximum crystal length L to the width W in the crystal. In this case, "maximum crystal length L" refers to the length of the crystal taken so that the crystal is at its longest in a crystal photograph taken with an optical microscope. Furthermore, "width W" refers to the length that forms an angle of 90 degrees with respect to the maximum crystal length and is the maximum length. The maximum crystal length L and width W are average values ​​calculated by measuring at least 30 crystals randomly selected from the optical microscope photograph.

[0170] The content of the seed crystals is preferably 0.001 to 1 mass %, more preferably 0.01 to 1 mass %, based on the total amount of the mixture of dihydroxy compounds.

[0171] The content of the seed crystals is preferably 0.001 to 1 mass %, more preferably 0.005 to 0.5 mass %, and even more preferably 0.01 to 0.1 mass %, based on the total mass of the crystallization solution.

[0172] Organic impurities and depolymerized products thereof Examples of the organic impurities and depolymerized products thereof include those mentioned above.

[0173] The content of organic impurities in the crystallization solution is preferably 0.001 to 10% by mass, more preferably 0.01 to 5% by mass, and even more preferably 0.1 to 2% by mass, based on the total mass of the crystallization solution. When two or more types of organic impurities are present, the total content thereof is preferably within the above range.

[0174] The content of depolymerized organic impurities in the crystallization solution is preferably 0.0001 to 1 mass %, more preferably 0.001 to 0.5 mass %, and even more preferably 0.01 to 0.2 mass %, relative to the total mass of the crystallization solution. When there are two or more types of depolymerized organic impurities, the total content thereof is preferably within the above range.

[0175] (Crystallization) The first dihydroxy compound can be obtained from the crystallization solution by carrying out crystallization. In this case, the first dihydroxy compound obtained by crystallization is usually in a crystalline form.

[0176] Crystallization is usually preferably carried out by heating and dissolving the dihydroxy compounds (the first dihydroxy compound and other dihydroxy compounds) and then cooling the solution to cause crystallization.

[0177] The heating temperature before crystallization varies depending on the ketone solvent and alcohol solvent used, but is preferably 50 to 90°C, more preferably 50 to 85°C, and even more preferably 50 to 80°C.

[0178] The crystallization temperature is not particularly limited, but is preferably −10 to 60° C., more preferably 0 to 50° C., and even more preferably 5 to 40° C., 10 to 40° C., 5 to 30° C., or 10 to 30° C.

[0179] The crystallization time is not particularly limited, but is preferably 5 minutes to 5 hours, more preferably 10 minutes to 3 hours, and even more preferably 30 minutes to 2 hours.

[0180] The desired dihydroxy compound can be produced as the first dihydroxy compound by appropriately changing the type and amount of the ketone solvent used, the type and amount of the alcohol solvent used, etc. By changing the composition of the solvent mixture, the solubility of the dihydroxy compound in the solvent mixture can be appropriately adjusted, and the desired dihydroxy compound can be made to be in a state where it is easy to precipitate.

[0181] In one embodiment, a dihydroxy compound represented by general formula (1') can be produced as the first dihydroxy compound. When a dihydroxy compound represented by general formula (1') is produced as the first dihydroxy compound, the ratio of the content (g / g) of the ketone solvent to the content (g / g) of the alcohol solvent relative to the total amount of the dihydroxy compound mixture in the crystallization solution (ketone solvent / alcohol solvent) is preferably 1 or more, more preferably 1 to 200, still more preferably 1 to 100, and still more preferably 1 to 30. It is more preferable that the ratio is 1 to 15, 1.1 to 15, 1.4 to 15, 1.8 to 15, 3 to 15, 6 to 15, 1 to 10, 1.1 to 10, 1.4 to 10, 1.8 to 10, 3 to 10, 6 to 10, 1 to 6, 1.1 to 6, 1.4 to 6, 1.8 to 6, 3 to 6, 1 to 3, 1.1 to 3, 1.4 to 3, 1.8 to 3, 1 to 1.8, 1.1 to 1.8, 1.4 to 1.8, 1 to 1.4, and 1.1 to 1.4. When the content ratio (ketone solvent / alcohol solvent) is 1 or more, the dihydroxy compound represented by general formula (1') can be suitably produced as the first dihydroxy compound.

[0182] The resulting dihydroxy compound represented by general formula (1') is preferably BNE, DP, 2,2'-bis(3-hydroxypropyloxy)-1,1'-binaphthalene, or 2,2'-bis(4-hydroxybutoxy)-1,1'-binaphthalene, more preferably BNE or DP, and even more preferably BNE.

[0183] Furthermore, when a dihydroxy compound represented by general formula (1') is produced as the first dihydroxy compound, the other dihydroxy compounds preferably include at least one of a dihydroxy compound represented by general formula (2') and a dihydroxy compound represented by general formula (3'), and more preferably include a dihydroxy compound represented by general formula (2') and a dihydroxy compound represented by general formula (3'). In this case, the dihydroxy compound represented by general formula (2') preferably contains at least one selected from the group consisting of BPEF, 9,9-bis[4-(2-hydroxyethoxy)-3-methylphenyl]fluorene, 9,9-bis[4-(2-hydroxyethoxy)-3-tert-butylphenyl]fluorene, 9,9-bis[4-(2-hydroxyethoxy)-3-isopropylphenyl]fluorene, 9,9-bis[4-(2-hydroxyethoxy)-3-cyclohexylphenyl]fluorene, and BPPEF, more preferably contains at least one of BPEF and BPPEF, and even more preferably contains BPPEF. The dihydroxy compound represented by general formula (3') preferably includes at least one selected from the group consisting of BNEF, 9,9-bis[6-(2-hydroxyethoxy)naphthalen-2-yl]fluorene, 9,9-bis[6-(3-hydroxypropoxy)naphthalen-2-yl]fluorene, and 9,9-bis[6-(4-hydroxybutoxy)naphthalen-2-yl]fluorene, and more preferably includes BNEF. In one embodiment, when the dihydroxy compound represented by general formula (1') is produced as the first dihydroxy compound, the other dihydroxy compounds are preferably BPPEF and BNEF.

[0184] When producing a dihydroxy compound represented by general formula (1') as the first dihydroxy compound, the ketone solvent preferably contains an aliphatic ketone solvent, more preferably contains at least one selected from the group consisting of acetone, methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), and diisobutyl ketone (DIBK), further preferably contains acetone and / or methyl ethyl ketone (MEK), and particularly preferably contains methyl ethyl ketone (MEK) from the viewpoint of improving yield and purity. In one embodiment, when producing a dihydroxy compound represented by general formula (1') as the first dihydroxy compound, the ketone solvent is MEK.

[0185] When producing a dihydroxy compound represented by general formula (1') as the first dihydroxy compound, the alcohol solvent preferably contains an aliphatic alcohol solvent, more preferably contains at least one selected from the group consisting of methanol, ethanol, isopropyl alcohol, 1-butanol, 2-butanol, and tert-butanol, further preferably contains methanol and / or ethanol, and particularly preferably contains methanol. In one embodiment, when producing a dihydroxy compound represented by general formula (1') as the first dihydroxy compound, the alcohol solvent is methanol.

[0186] The total content of the ketone solvent and the alcohol solvent in the crystallization solution is preferably 0.5 to 10 g / g, more preferably 1 to 4 g / g, 1.1 to 4 g / g, 1.8 to 4 g / g, 3 to 4 g / g, 1 to 3 g / g, 1.1 to 3 g / g, 1.8 to 3 g / g, 1 to 1.8 g / g, 1.1 to 1.8 g / g, or 1 to 1.1 g / g, relative to the total amount of the mixture of dihydroxy compounds.

[0187] In another embodiment, the dihydroxy compound represented by general formula (2') can be produced as the first dihydroxy compound. When the dihydroxy compound represented by general formula (2') is produced as the first dihydroxy compound, the alcoholic solvent is methanol. Furthermore, the ratio of the ketone solvent content (g / g) to the alcoholic solvent content (g / g) relative to the total amount of the dihydroxy compound mixture in the crystallization solution (ketone solvent / alcoholic solvent) is preferably less than 1, and more preferably 0.8 or less, 0.5 or less, 0.1 to 0.8, 0.2 to 0.8, 0.1 to 0.5, 0.2 to 0.5, 0.1 to 0.3, or 0.2 to 0.3. When the alcoholic solvent and the ratio (ketone solvent / alcoholic solvent) are less than 1, the dihydroxy compound represented by general formula (2') can be suitably produced as the first dihydroxy compound.

[0188] The resulting dihydroxy compound represented by general formula (2') is preferably BPEF, 9,9-bis[4-(2-hydroxyethoxy)-3-methylphenyl]fluorene, 9,9-bis[4-(2-hydroxyethoxy)-3-tert-butylphenyl]fluorene, 9,9-bis[4-(2-hydroxyethoxy)-3-isopropylphenyl]fluorene, 9,9-bis[4-(2-hydroxyethoxy)-3-cyclohexylphenyl]fluorene, or BPPEF, more preferably BPEF or BPPEF, and even more preferably BPPEF.

[0189] Furthermore, when a dihydroxy compound represented by general formula (2') is produced as the first dihydroxy compound, the other dihydroxy compounds preferably include at least one of a dihydroxy compound represented by general formula (1') and a dihydroxy compound represented by general formula (3'), and more preferably include a dihydroxy compound represented by general formula (1') and a dihydroxy compound represented by general formula (3'). In this case, the dihydroxy compound represented by general formula (1') preferably includes at least one selected from the group consisting of BNE, DP, 2,2'-bis(3-hydroxypropyloxy)-1,1'-binaphthalene, and 2,2'-bis(4-hydroxybutoxy)-1,1'-binaphthalene, more preferably includes at least one of BNE and DP, and even more preferably includes BNE. Furthermore, the dihydroxy compound represented by general formula (3') preferably includes at least one selected from the group consisting of BNEF, 9,9-bis[6-(2-hydroxyethoxy)naphthalen-2-yl]fluorene, 9,9-bis[6-(3-hydroxypropoxy)naphthalen-2-yl]fluorene, and 9,9-bis[6-(4-hydroxybutoxy)naphthalen-2-yl]fluorene, and more preferably includes BNEF. In one embodiment, when the dihydroxy compound represented by general formula (2') is produced as the first dihydroxy compound, the other dihydroxy compounds are preferably BNE and BNEF.

[0190] When a dihydroxy compound represented by general formula (2') is produced as the first dihydroxy compound, the ketone solvent preferably contains an aliphatic ketone solvent, more preferably contains at least one selected from the group consisting of acetone, methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), and diisobutyl ketone (DIBK), further preferably contains acetone and / or methyl ethyl ketone (MEK), and particularly preferably contains methyl ethyl ketone (MEK) from the viewpoint of improving yield and purity. In one embodiment, when a dihydroxy compound represented by general formula (2') is produced as the first dihydroxy compound, the ketone solvent is MEK.

[0191] The total content of the ketone solvent and the alcohol solvent in the crystallization solution is preferably 1 to 20 g / g, more preferably 1 to 15 g / g, 2 to 15 g / g, 3 to 15 g / g, 1 to 8 g / g, 2 to 8 g / g, 3 to 8 g / g, 1 to 5 g / g, 2 to 5 g / g, or 3 to 5 g / g, relative to the total amount of the mixture of dihydroxy compounds.

[0192] <Method for Producing Recycled Resin> According to one aspect of the present invention, there is provided a method for producing a recycled resin, which comprises polymerizing the dihydroxy compound produced by the method described above.

[0193] A known polymerization technique can be appropriately employed to obtain a recycled resin from a dihydroxy compound. In one embodiment, the recycled resin can be produced by subjecting a dihydroxy compound and a carbonate diester to a solution condensation method in the presence of a basic compound catalyst and / or a transesterification catalyst, or in the absence of a catalyst. In addition, from the viewpoint of adjusting the physical properties of the recycled resin, a separately prepared dihydroxy compound can be used as a monomer together with the dihydroxy compound produced from the waste resin composition.

[0194] The carbonic acid diester is not particularly limited, but examples thereof include diphenyl carbonate, ditolyl carbonate, bis(chlorophenyl) carbonate, m-cresyl carbonate, dimethyl carbonate, diethyl carbonate, dibutyl carbonate, dicyclohexyl carbonate, etc. Among these, diphenyl carbonate is preferred.

[0195] The amount of the diester carbonate compound used is preferably 0.97 to 1.20 mol, more preferably 0.98 to 1.10 mol, and even more preferably 1.00 to 1.10 mol, per mol of the dihydroxy compound.

[0196] The basic compound catalyst is not particularly limited, but examples thereof include alkali metal compounds, alkaline earth metal compounds, and nitrogen-containing compounds.

[0197] The alkali metal compound is not particularly limited, and examples thereof include organic acid salts, inorganic salts, oxides, hydroxides, hydrides, and alkoxides of alkali metals.Specific examples thereof include sodium hydroxide, potassium hydroxide, cesium hydroxide, lithium hydroxide, sodium bicarbonate, sodium carbonate, potassium carbonate, cesium carbonate, lithium carbonate, sodium acetate, potassium acetate, cesium acetate, lithium acetate, sodium stearate, potassium stearate, cesium stearate, lithium stearate, sodium borohydride, sodium phenylborohydride, sodium benzoate, potassium benzoate, cesium benzoate, lithium benzoate, disodium hydrogen phosphate, dipotassium hydrogen phosphate, dilithium hydrogen phosphate, disodium phenylphosphate, disodium salt, dipotassium salt, dicesium salt, or dilithium salt of bisphenol A, and sodium salt, potassium salt, cesium salt, or lithium salt of phenol.

[0198] The alkaline earth metal compound is not particularly limited, and examples thereof include organic acid salts, inorganic salts, oxides, hydroxides, hydrides, and alkoxides of alkaline earth metal compounds. Specific examples include magnesium hydroxide, calcium hydroxide, strontium hydroxide, barium hydroxide, magnesium hydrogen carbonate, calcium hydrogen carbonate, strontium hydrogen carbonate, barium hydrogen carbonate, magnesium carbonate, calcium carbonate, strontium carbonate, barium carbonate, magnesium acetate, calcium acetate, strontium acetate, barium acetate, magnesium stearate, calcium stearate, calcium benzoate, and magnesium phenylphosphate.

[0199] The nitrogen-containing compound is not particularly limited, but examples thereof include quaternary ammonium hydroxides, salts thereof, amines, etc. Specific examples include quaternary ammonium hydroxides having an alkyl group, an aryl group, etc., such as tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, and trimethylbenzylammonium hydroxide; tertiary amines such as triethylamine, dimethylbenzylamine, and triphenylamine; secondary amines such as diethylamine and dibutylamine; primary amines such as propylamine and butylamine; imidazoles such as 2-methylimidazole, 2-phenylimidazole, and benzimidazole; ammonia, tetramethylammonium borohydride, tetrabutylammonium borohydride, tetrabutylammonium tetraphenylborate, and tetraphenylammonium tetraphenylborate.

[0200] Examples of the transesterification catalyst include salts of zinc, tin, zirconium, lead, etc. Specific examples include zinc acetate, zinc benzoate, zinc 2-ethylhexanoate, tin(II) chloride, tin(IV) chloride, tin(II) acetate, tin(IV) acetate, dibutyltin dilaurate, dibutyltin oxide, dibutyltin dimethoxide, zirconium acetylacetonate, zirconium oxyacetate, zirconium tetrabutoxide, lead(II) acetate, and lead(IV) acetate.

[0201] The above-mentioned basic compound catalysts and transesterification catalysts may be used alone or in combination of two or more kinds.

[0202] The amount of the basic compound catalyst and the transesterification catalyst (total amount when used in combination) used is 1 × 10 per mole of the dihydroxy compound. －９ ~1 x 10 －３ mol, preferably 1×10 －７ ~1 x 10 －４ More preferably, it is moles.

[0203] In the melt polycondensation method, it is desirable to melt a dihydroxy compound and a carbonate diester in a reaction vessel and then carry out the reaction in a state in which the produced monohydroxy compound remains. In order to retain the monohydroxy compound, the pressure can be controlled by, for example, closing the reaction vessel or reducing or increasing the pressure.

[0204] The recycled resin obtained by the above method can be suitably used in plastic products.

[0205] The present invention will be described in detail below with reference to examples, but the technical scope of the present invention is not limited thereto. Unless otherwise specified, "parts" and "%" in the examples represent "parts by mass" and "% by mass", respectively.

[0206] Example 1 A polycarbonate resin (molar ratio: BNE / BPPEF / BNEF = 52 / 21 / 27) containing 2,2'-bis(1-hydroxymethoxy)-1,1'-binaphthalene, 2,2'-bis(2-hydroxyethoxy)-1,1'-binaphthalene (BNE), 9,9-bis[4-(2-hydroxyethoxy)-3-phenylphenyl]fluorene (BPPEF), and 9,9-bis[6-(1-hydroxymethoxy)naphthalen-2-yl]fluorene (BNEF) as structural units was used as a waste resin composition.

[0207] The structures of BNE, BPPEF, and BNEF are as follows:

[0208] (Step (a1)) 100 parts by weight of polycarbonate resin, 88 parts by weight of 48% aqueous sodium hydroxide solution, and 734 parts by weight of methyl ethyl ketone (MEK), a ketone solvent, were charged into a reactor equipped with a stirrer and a condenser, and reacted for 3 hours under heated reflux. Thereafter, the liquid temperature was cooled to 70 to 75°C, and 178 parts by weight of ion-exchanged water was added. After stirring and standing, the aqueous phase was separated, and the organic phase was washed with ion-exchanged water. MEK was partially distilled off from the organic phase to obtain a reaction solution.

[0209] (Step (b1)) Methanol, an alcoholic solvent, was added to the reaction solution so that the weight of the mixture became 0.01 times that of MEK. The mixed solution was heated to 60 to 65°C, and it was confirmed that the dihydroxy compound had completely dissolved. Next, the mixed solution was cooled to 20°C, and then BNE crystals, which had been separately prepared as seed crystals, were added to the mixed solution to prepare a crystallization solution.

[0210] The mixture was cooled to 10°C and allowed to stand for at least 1 hour to allow crystallization. The precipitate was filtered, washed with toluene, and the resulting crystals were dried to obtain crystals of the dihydroxy compound. The molar ratio of BNE / BPPEF / BNEF in the crystals of the dihydroxy compound was measured by the following method.

[0211] The purity of the dihydroxy compound crystals was analyzed by high performance liquid chromatography (HPLC). Detailed analysis conditions are as follows.

[0212] Apparatus: Agilent Technologies 1260 Infinity Column: TOSOY TSK-GEL ODS-80-Ts (5 μm, 4.6 mmφ x 250 mm) Eluent: 0 min acetonitrile / water = 46.3 / 53.7 (vol%); 15 min acetonitrile / water = 46.3 / 53.7 (vol%); 30 min acetonitrile / water = 95 / 5 (vol%); 40 min acetonitrile / water = 95 / 5 (vol%) Flow rate: 1 mL / min Column temperature: 25°C Measurement wavelength: 254 nm Injection volume: 5 μm Sample concentration: 10 mg / 10 mL (acetonitrile solvent)

[0213] The crystallization solution (mixture of dihydroxy compounds before crystallization) was measured by HPLC, and the molar ratio of the dihydroxy compounds was calculated from the peak area percentage of the chromatograph of the dihydroxy compound crystals, using the peak area percentage of the obtained chromatograph as a reference.

[0214] The molar ratio of BNE / BPPEF / BNEF in the dihydroxy compound crystals was 94 / 3 / 3. This result demonstrates that the first dihydroxy compound, BNE, was successfully separated from the other dihydroxy compounds, BPPEF and BNEF, using polycarbonate resin as the raw material.

[0215] The waste resin composition used contains a polycarbonate resin but does not contain other synthetic resins. However, for example, when the waste resin composition further contains an impurity resin (such as a cyclic polyolefin) having at least one structural unit selected from the group consisting of general formulas (6) to (8) in addition to the polycarbonate resin, the impurity resin (such as a cyclic polyolefin) is not depolymerized in step (a-1) and can therefore be easily separated from the dihydroxy compound.

[0216] Examples 2 to 8 and Comparative Example 1 Dihydroxy compounds were produced in the same manner as in Example 1, except that the type and amount of the ketone solvent used in step (a1) (the content (g / g) of the ketone solvent relative to the total amount of the dihydroxy compound mixture in the crystallization solution), the type of seed crystals used in step (b1), and the type and amount of the alcohol solvent used in step (b1) (the content (g / g) of the alcohol solvent relative to the total amount of the dihydroxy compound mixture in the crystallization solution) were changed as shown in Table 1.

[0217] [Evaluation of Solidification of Crystallization Solution and Yield] For Examples 1 to 8 and Comparative Example 1, evaluation of solidification of the crystallization solution was carried out, and the yield was calculated.

[0218] (Evaluation of Solidification of Reaction Solution) The degree of solidification of the crystallization solution in step (b1) was evaluated. The specific evaluation method is as follows.

[0219] In step (b1), an alcohol solvent is added to the reaction solution obtained in step (a1), and the resulting mixed solution is heated to 60-65°C until it is confirmed that the dihydroxy compound is completely dissolved, after which it is cooled to 20°C. The crystallized solution after 2 hours of cooling was visually inspected and evaluated according to the following criteria. The results are shown in Table 1 below. A: The crystallized solution has not solidified and can be stirred. B: The crystallized solution has solidified and cannot be stirred.

[0220] (Yield) The weight of the crystals of the dihydroxy compound obtained in step (b1) was measured, and the following yields were calculated. Note that yield A was calculated when the first dihydroxy compound was BNE, and yield B was calculated when the first dihydroxy compound was BPPEF. The obtained results are shown in Table 1 below.

[0221]

[0222] The results in Table 1 show that highly pure crystals of the dihydroxy compound were obtained in Examples 1 to 8. Furthermore, the first dihydroxy compound was BNE in Examples 1 to 4 and 8, and BPPEF in Examples 5 to 7. This shows that the desired first dihydroxy compound can be produced by adjusting the types and amounts of the ketone solvent and alcohol solvent used.

Claims

1. A method for producing a dihydroxy compound from a waste resin composition, comprising: [In the formula, X ａ , X ｂ , X ｃ , X ｄ , X ｅ , and X ｆ each independently represents an alkylene group having 1 to 4 carbon atoms; ａ , R ｂ , R ｃ , R ｃｃ , R ｄ , R ｄｄ , R ｅ , R ｅｅ , R ｆ、 and R ｆｆ each independently represents a halogen atom, an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, a cycloalkyl group having 5 to 20 carbon atoms, a cycloalkoxy group having 5 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, a heteroaryl group having 3 to 20 carbon atoms containing one or more hetero ring atoms selected from O, N, and S, an aryloxy group having 6 to 20 carbon atoms, and —C≡C—R ｉ is selected from R ｉ represents an aryl group having 6 to 20 carbon atoms or a heteroaryl group having 3 to 20 carbon atoms and containing one or more hetero ring atoms selected from O, N, and S; a, b, c, d, e, and f each independently represent an integer of 0 to 10; h, i, j, j', k, k', m, m', n, and n' each independently represent an integer of 0 to 4; R ｇ each independently represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.], and an alkaline solution containing a ketone solvent and water is treated to produce a compound represented by the following general formulas (1') to (4'): [wherein each symbol has the same meaning as in the above general formulae (1) to (4)], and at least one other dihydroxy compound selected from the group consisting of general formulae (1') to (4'), and a step (a1) of obtaining a reaction solution containing a ketone solvent and a mixture of dihydroxy compounds, and a step (b1) of crystallizing the first dihydroxy compound from a crystallization solution obtained by adding an alcohol solvent to the reaction solution.

2. The method according to claim 1, wherein the first dihydroxy compound is a dihydroxy compound represented by general formula (1'), and the ratio of the ketone solvent content (g / g) to the alcohol solvent content (g / g) relative to the total amount of the dihydroxy compound mixture in the crystallization solution (ketone solvent / alcohol solvent) is 1 or more.

3. The production method according to claim 2, wherein the dihydroxy compound represented by the general formula (1') includes 2,2'-bis(1-hydroxymethoxy)-1,1'-binaphthalene and 2,2'-bis(2-hydroxyethoxy)-1,1'-binaphthalene (BNE).

4. The method according to claim 2, wherein the other dihydroxy compound comprises at least one of a dihydroxy compound represented by general formula (2') and a dihydroxy compound represented by general formula (3').

5. The manufacturing method according to claim 4, wherein the dihydroxy compound represented by the general formula (2') includes 9,9-bis[4-(2-hydroxyethoxy)-3-phenylphenyl]fluorene (BPPEF), and the dihydroxy compound represented by the general formula (3') includes 9,9-bis[6-(1-hydroxymethoxy)naphthalen-2-yl]fluorene (BNEF).

6. The method according to claim 2, wherein the alcohol solvent is methanol.

7. The method according to claim 1, wherein the first dihydroxy compound is a dihydroxy compound represented by general formula (2'), the alcohol solvent is methanol, and the ratio of the ketone solvent content (g / g) to the alcohol solvent content (g / g) relative to the total amount of the dihydroxy compound mixture in the crystallization solution (ketone solvent / alcohol solvent) is less than 1.

8. The method according to claim 7, wherein the dihydroxy compound represented by the general formula (2') includes 9,9-bis[4-(2-hydroxyethoxy)-3-phenylphenyl]fluorene (BPPEF).

9. The method according to claim 7, wherein the other dihydroxy compound comprises at least one of a dihydroxy compound represented by general formula (1') and a dihydroxy compound represented by general formula (3').

10. The production method according to claim 9, wherein the dihydroxy compound represented by general formula (1') includes 2,2'-bis(1-hydroxymethoxy)-1,1'-binaphthalene and 2,2'-bis(2-hydroxyethoxy)-1,1'-binaphthalene (BNE), and the dihydroxy compound represented by general formula (3') includes 9,9-bis[6-(1-hydroxymethoxy)naphthalen-2-yl]fluorene (BNEF).

11. The method according to claim 1, wherein the total content of the ketone solvent and the alcohol solvent in the crystallization solution is 1 to 20 g / g based on the total amount of the mixture of dihydroxy compounds.

12. The waste resin composition is a compound represented by the following general formulas (6) to (8): [In the formula, X ｇ each independently represents an alkylene group having 1 to 10 carbon atoms; ｊ , R ｋ , and R ｌ each independently represents a halogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 5 to 20 carbon atoms, a substituted or unsubstituted cycloalkoxy group having 5 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, a substituted or unsubstituted heteroaryl group having 3 to 20 carbon atoms containing one or more hetero ring atoms selected from O, N, and S, a substituted or unsubstituted aryloxy group having 6 to 20 carbon atoms, and —C≡C—R ｉ is selected from R ｉ represents a substituted or unsubstituted aryl group having 6 to 20 carbon atoms or a heteroaryl group having 3 to 20 carbon atoms and containing one or more hetero ring atoms selected from O, N, and S; each p independently represents an integer of 0 or 1; each q, r, and s independently represents an integer of 0 to 10; and t represents an integer of 1 to 3, where q is 2 or more and two R ｊ When two R ｊ may be joined together to form a ring structure, r is 2 or more, and two R ｋ When two R ｋ may be joined together to form a ring structure, s is 2 or more, and two R ｌ When two R ｌ may be joined together to form a ring structure, R ｍ represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.] The method according to any one of claims 1 to 11, wherein the impurity resin has at least one structural unit selected from the group consisting of:

13. A method for producing a recycled resin, comprising polymerizing a dihydroxy compound produced by the method according to any one of claims 1 to 11.

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