Method for producing polythiol composition, method for producing polymerizable composition, and method for producing resin

Abstract

A method for producing a polythiol composition, the method comprising a reaction step in which a thiourethane resin and at least one nitrogenous compound selected from the group consisting of quaternary ammonium salts and amine compounds are reacted in the presence of water to yield a polythiol composition.

Description

Method for producing polythiol composition, method for producing polymerizable composition, and method for producing resin

[0001] The present disclosure relates to a method for producing a polythiol composition, a method for producing a polymerizable composition, and a method for producing a resin.

[0002] Plastic lenses, which are lenses containing resin, are lighter and less likely to break than inorganic lenses, and can be dyed, and therefore have rapidly become popular in recent years for use as eyeglass lenses, camera lenses, etc. For example, lenses containing thiourethane resins have been widely studied (see, for example, Patent Documents 1 to 3).

[0003] As raw materials for producing thiourethane resins (hereinafter also referred to as "thiourethane resin raw materials"), for example, polythiol compositions such as 4,8-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane and polyisocyanate compounds such as m-xylylene diisocyanate (XDI) are used. Polyisocyanate compounds are produced, for example, from polyamine compounds. Polyamine compounds, which are raw materials for polyisocyanate compounds, also fall under the category of thiourethane resin raw materials (i.e., raw materials for producing thiourethane resins).

[0004] Lenses containing thiourethane resins (e.g., eyeglass lenses) are manufactured by cutting molded articles containing thiourethane resins. As a result, a large amount of cutting powder containing thiourethane resins may be generated as waste during the lens manufacturing process. Furthermore, in the process of manufacturing molded articles containing thiourethane resins, defective molded or processed products may be generated. Such waste is usually incinerated or landfilled without being effectively utilized (i.e., recycled). Therefore, from the perspective of effective material utilization, a technology for producing a polythiol composition using cutting powder containing thiourethane resins or defective molded or processed products as a starting material has been developed (see, for example, Patent Document 4). Patent Document 4 discloses the production of a polythiol composition by reacting an amine compound as a base with an organic solvent (high-boiling alcohol, toluene) that is poorly miscible with water.

[0005] JP-A-63-46213 JP-A-2-270859 JP-A-7-252207 International Publication No. 2021 / 157701

[0006] However, it has not been possible to efficiently carry out the reaction when producing a polythiol composition and obtain the polythiol composition in a short time. Therefore, from the viewpoint of reducing energy consumption and suppressing the production of by-products, there has been a strong demand for the development of a reaction system that can produce a polythiol composition in a short reaction time using a thiourethane resin as a starting material.

[0007] Under these circumstances, an object of one aspect of the present disclosure is to provide a method for producing a polythiol composition that can produce a polythiol composition in a short reaction time using a thiourethane resin as a starting material, a method for producing a polymerizable composition using the method for producing a polythiol composition, and a method for producing a resin using the method for producing a polymerizable composition.

[0008] Embodiments of the present disclosure relate to the following [1] to [8]. [1] A method for producing a polythiol composition, comprising a reaction step of reacting a thiourethane resin and at least one nitrogen-containing compound selected from the group consisting of a quaternary ammonium salt and an amine compound in the presence of water to produce a polythiol composition. [2] A method for producing a polythiol composition according to [1] above, wherein the water content in the reaction system of the reaction step is 2 to 50 mass%. [3] A method for producing a polythiol composition according to [1] or [2] above, wherein the quaternary ammonium salt comprises a quaternary ammonium cation and a counter anion, and the counter anion is a hydroxide ion. [4] A method for producing a polythiol composition according to any of [1] to [3] above, wherein the amine compound is at least one selected from the group consisting of a primary amine, a secondary amine, and a tertiary amine. [5] A method for producing a polythiol composition according to any of [1] to [4] above, wherein the reaction system in the reaction step further contains an alcohol. [6] A method for producing a polythiol composition according to [5] above, wherein the alcohol includes one or more alcohols miscible with water. [7] A method for producing a polymerizable composition, comprising: producing a polythiol composition by the method for producing a polythiol composition according to any one of [1] to [6] above; and mixing the produced polythiol composition with a polyisocyanate compound to obtain a polymerizable composition containing the polythiol composition and the polyisocyanate compound. [8] A method for producing a resin, comprising: producing a polymerizable composition by the method for producing a polymerizable composition according to [7] above; and curing the polymerizable composition to obtain a resin.

[0009] According to one aspect of the present disclosure, it is possible to provide a method for producing a polythiol composition that can produce a polythiol composition in a short reaction time using a thiourethane resin as a starting material, a method for producing a polymerizable composition using the method for producing a polythiol composition, and a method for producing a resin using the method for producing a polymerizable composition.

[0010] The following describes an example of an embodiment of the present disclosure. However, the embodiments described below are merely examples for embodying the technical concept of the present disclosure, and the present disclosure is not limited to the following description. The present disclosure also includes any embodiment or combination of any of the features described herein. In this specification, preferred specifications may be selected arbitrarily, and combinations of preferred specifications are considered more preferable. In this specification, the term "XX to YY" means "XX or greater and YY or less." In this specification, for preferred numerical ranges (e.g., ranges of content, etc.), lower and upper limits described in stages can be independently combined. For example, a description of "preferably 10 to 90, more preferably 30 to 60" can be combined with the "preferable lower limit (10)" and the "more preferable upper limit (60)" to obtain "10 to 60." In this specification, when multiple substances corresponding to each component are present in the composition, the amount of each component in the composition refers to the total amount of the multiple substances present in the composition, unless otherwise specified. As used herein, the term "process" refers not only to an independent process, but also to processes that cannot be clearly distinguished from other processes, as long as the intended purpose of the process is achieved. As used herein, the term "reaction system" refers to the "reaction system of the reaction process in the method for producing a polythiol composition." The reaction system in the reaction process includes, in addition to the essential components consisting of a thiourethane resin, a nitrogen-containing compound, and water, optional components such as alcohol and a reaction solvent. Therefore, the content (mass%) in the reaction system refers to the content (mass%) when the total content of the essential components and optional components in the reaction system is taken as 100% by mass. In the present specification, in the case of a reaction system containing a compound that corresponds to both an alcohol and an amine compound, such as monoethanolamine, the "total content of the essential components and optional components in the reaction system" is calculated by counting only one of the alcohol and the amine compound, without double-counting both the alcohol and the amine compound.Here, the "content (mass%) of alcohol in the reaction system" is the value obtained by dividing the "mass of compounds corresponding to both alcohols and amine compounds" by the "total content of essential components and optional components in the reaction system," calculated by counting only either alcohols or amine compounds, and the "content (mass%) of amine compounds in the reaction system" is the value obtained by dividing the "mass of compounds corresponding to both alcohols and amine compounds" by the "total content of essential components and optional components in the reaction system," calculated by counting only alcohols or amine compounds, so that the "content (mass%) of alcohol in the reaction system" and the "content (mass%) of amine compounds in the reaction system" are the same value. In this specification, the expression "containing a certain component (hereinafter referred to as "component X") as a "major component" means that the content of component X (when component X consists of two or more compounds, the total content of the two or more compounds) is 50 mass% or more of the total amount of the reaction system (composition). The content of the main component, component X, is preferably 60% by mass or more, more preferably 70% by mass or more, and particularly preferably 80% by mass or more, based on the total amount of the reaction system (composition). In this specification, the "high boiling point" in "high boiling point alcohol" means 140°C or more. In this specification, R. ３ , R ４ , R ５ , R ６ , R １１ , R １２ The definition and examples of R are the same as those of R in the quaternary ammonium.

[0011] [Method for Producing a Polythiol Composition] A method for producing a polythiol composition according to an embodiment of the present disclosure includes a reaction step in which a thiourethane resin and at least one nitrogen-containing compound selected from the group consisting of quaternary ammonium salts and amine compounds are reacted in the presence of water to produce a polythiol composition. The method for producing a polythiol composition according to an embodiment of the present disclosure involves reacting a thiourethane resin and at least one nitrogen-containing compound selected from the group consisting of quaternary ammonium salts and amine compounds in the presence of water, thereby enabling the production of a polythiol composition using a thiourethane resin as a starting material in a short reaction time. When the reaction system further contains alcohol, alcoholysis occurs in the reaction step, in which the thiourethane resin is further decomposed by the alcohol, and this alcoholysis produces the target polythiol composition. When the reaction system further contains alcohol, it is believed that the alcohol functions as a decomposing agent in the alcoholysis, and the nitrogen-containing compound functions as a decomposing aid in the alcoholysis. When the reaction system does not contain alcohol, it is believed that the counter anion in the quaternary ammonium salt as the nitrogen-containing compound or the amine compound itself undergoes a nucleophilic reaction with the carbon of the carbonyl group of the thiourethane resin (see Reaction Formula (X), Reaction Formula (6), and Reaction Formula (7) described below).

[0012] The method for producing a polythiol composition according to an embodiment of the present disclosure includes at least a reaction step, and optionally includes other steps such as a separation step, a classification step, a sieving step, a washing step, and a crushing (pulverization) step. Each step that can be included in the method for producing a polythiol composition will be described below.

[0013] [Reaction Step] The reaction step is a step in which a thiourethane resin, a nitrogen-containing compound, and, if necessary, an optional component such as an alcohol are reacted in the presence of water to produce a polythiol composition.

[0014] <Thiourethane Resin> The thiourethane resin is the starting material in this step and in the method for producing a polythiol composition. The thiourethane resin is not particularly limited, and examples thereof include thiourethane resins described in publicly known documents such as JP-A-63-46213, JP-A-2-270859, JP-A-7-252207, and WO 2008 / 047626.

[0015] Thiourethane resins are typically produced as reaction products using polyisocyanate compounds and polythiol compositions as raw materials. Examples of thiourethane resins include thiourethane resins obtained from high refractive index lens materials such as MR-6, MR-7, MR-8, MR-8Plus, MR-60, MR-10, and MR-20 (all manufactured by Mitsui Chemicals, Inc.); EYAS1.60 (manufactured by HOYA Corporation); and the like.

[0016] The thiourethane resin is preferably recovered during at least one of the processes of manufacturing eyeglass lenses, manufacturing eyeglasses, and disposing of eyeglasses. This embodiment allows for the recycling of thiourethane resin, a material for eyeglass lenses. Here, the process of manufacturing eyeglass lenses refers to the process of producing a resin by blending monomers, which are resin raw materials, and then performing cast polymerization, and / or the process of cutting a resin molded body to obtain eyeglass lenses. The process of manufacturing eyeglasses refers to the process of manufacturing eyeglasses by combining eyeglass lenses with other components such as eyeglass frames. The process of disposing of eyeglasses refers to the process of disposing of eyeglasses that have been manufactured but are no longer needed, used eyeglasses, etc. In any of these processes, thiourethane resin, a material for eyeglass lenses, may be generated as waste. Preferably, the thiourethane resin produced during at least one of these processes is used as a starting material, and this thiourethane resin is reacted with a nitrogen-containing compound and, if necessary, an optional component such as an alcohol, in the presence of water to obtain a polythiol composition, which is a decomposition product of the thiourethane resin.

[0017] As described above, the method for producing a polythiol composition of the present disclosure uses used thiourethane resin to produce the polythiol composition, thereby reducing the amount of thiourethane resin incinerated and disposed of, thereby reducing the generation of greenhouse gases such as carbon dioxide, sulfur oxides, nitrogen oxides, and other air pollutants. Furthermore, because thiourea is not used in the production of the polythiol composition, no thiourea-containing wastewater is produced, making this an environmentally friendly production method. To give a specific example, when 1 kg of thiourethane resin is incinerated and disposed of, the carbon, nitrogen, and sulfur atom contents in the thiourethane resin are 48.5 mass%, 7.6 mass%, and 30.2 mass%, respectively. When this thiourethane resin is burned, various types of oxides of carbon atoms, nitrogen atoms, and sulfur atoms are generated as gases depending on the combustion method. If the products are carbon dioxide, nitric oxide, and sulfur dioxide, then when 1 kg of thiourethane resin is disposed of, 1.78 kg of carbon dioxide, 0.16 kg of nitric oxide, and 0.6 kg of sulfur dioxide are generated. The method for producing a polythiol composition according to the present disclosure makes it possible to reduce the generation of carbon dioxide, nitrogen monoxide, and sulfur dioxide.

[0018] The starting material preferably contains cutting powder containing a thiourethane resin. In the step of producing a polythiol composition in this embodiment, the cutting powder containing a thiourethane resin is contacted with a nitrogen-containing compound, and, if necessary, an optional component such as an alcohol, in the presence of water, thereby reacting the thiourethane resin, the nitrogen-containing compound, and the optional component such as the alcohol in the presence of water. In this embodiment, the reactivity of the nitrogen-containing compound, the thiourethane resin in the starting material, the optional component such as the alcohol, and water is superior, so the polythiol composition can be produced more effectively.

[0019] (Powder containing thiourethane resin) In the reaction step, it is preferable to contact a powder containing a thiourethane resin (hereinafter also referred to as "thiourethane resin powder") with a nitrogen-containing compound and optional components such as alcohol in the presence of water, thereby reacting the thiourethane resin in the powder with the nitrogen-containing compound, optional components such as alcohol, and water. This can further improve the reaction efficiency between the thiourethane resin, the nitrogen-containing compound, optional components such as alcohol, and water. The method for contacting the thiourethane resin, the nitrogen-containing compound, optional components such as alcohol, and water is not particularly limited, and examples include a method in which the thiourethane resin powder, nitrogen-containing compound, and water (and, if necessary, alcohol, reaction solvent, etc.) are placed in a reaction vessel and stirred. In this example, there is no particular limitation on the order in which the thiourethane resin powder, nitrogen-containing compound, and water (and, if necessary, alcohol, reaction solvent, etc.) are placed in the reaction vessel.

[0020] The thiourethane resin powder is not particularly limited, but is preferably a cutting powder (including the concept of polishing powder; the same applies hereinafter) of a molded body containing a thiourethane resin and / or the above cutting powder that has been sieved (i.e., cutting powder that has passed through a sieve). Cutting powder of a molded body containing a thiourethane resin is generated, for example, when a molded body containing a thiourethane resin is cut to produce an optical material (e.g., a lens). The thiourethane resin powder may also be a clumped powder obtained by crushing and / or pulverizing a molded body containing a thiourethane resin.

[0021] The content of the thiourethane resin in the reaction system in the reaction step is not particularly limited, but from the viewpoint of further improving the reactivity of the thiourethane resin, it is preferably 2 to 50 mass%, more preferably 4 to 30 mass%, and particularly preferably 6 to 20 mass%.

[0022] (Polyisocyanate Compound as a Raw Material for Thiourethane Resin) The polyisocyanate compound as a raw material for the thiourethane resin may be one type only, or two or more types. The polyisocyanate compound as a raw material for the thiourethane resin preferably includes a polyisocyanate compound containing two or more isocyanate groups. Examples of polyisocyanate compounds as raw materials for the thiourethane resin include known polyisocyanate compounds described in the above-mentioned known documents (i.e., JP-A-63-46213, JP-A-2-270859, JP-A-7-252207, WO 2008 / 047626, etc.).

[0023] (Polythiol composition as a raw material for thiourethane resin) The polythiol composition as a raw material for thiourethane resin may be only one type of polythiol compound, or may be two or more types of polythiol compounds. The polythiol composition as a raw material for thiourethane resin is not particularly limited as long as it contains a polythiol compound containing two or more thiol groups (i.e., mercapto groups). Examples of polythiol compositions as raw materials for thiourethane resin include known polythiol compositions described in the above-mentioned known documents (i.e., JP-A-63-46213, JP-A-2-270859, JP-A-7-252207, WO 2008 / 047626, etc.).

[0024] The thiourethane resin may contain other components in addition to the polymer of at least one polyisocyanate compound and a polythiol composition. For other components that can be contained in the thiourethane resin, refer to the components that can be contained in the polymerizable composition described below.

[0025] <Nitrogen-Containing Compound> The nitrogen-containing compound is at least one selected from the group consisting of a quaternary ammonium salt and an amine compound. That is, the nitrogen-containing compound may be a quaternary ammonium salt alone, an amine compound alone, or a mixture of a quaternary ammonium salt and an amine compound.

[0026] The content of the nitrogen-containing compound in the reaction system in the reaction step is not particularly limited, but from the viewpoint of further improving the reactivity with the thiourethane resin, it is preferably 1 to 40 mass%, more preferably 2 to 30 mass%, and particularly preferably 3 to 20 mass%.

[0027] (Charge amount of nitrogen-containing compound) In the reaction step, the charge mass ratio of the nitrogen-containing compound to the thiourethane resin (i.e., charge mass ratio [nitrogen-containing compound / thiourethane resin]) can be appropriately adjusted, but is preferably 0.1 to 10, more preferably 0.2 to 9, and particularly preferably 0.4 to 6. When the charge mass ratio [nitrogen-containing compound / thiourethane resin] is 0.1 or more, the production of the polythiol composition is further promoted. When the charge mass ratio [nitrogen-containing compound / thiourethane resin] is 10 or less, the nitrogen-containing compound remaining in the reaction mixture can be further suppressed.

[0028] In the reaction step, the number of millimoles of the nitrogen-containing compound charged per 1 g of the thiourethane resin is preferably 1.0 to 100.0 mmol / g, more preferably 2.0 to 50.0 mmol / g, and particularly preferably 3.0 to 25.0 mmol / g.

[0029] In the reaction step, the charge equivalent of the nitrogen-containing compound relative to the thiourethane resin (charge equivalent [nitrogen-containing compound / thiourethane resin]) is preferably 1.0 to 10.0, more preferably 1.0 to 8.0, and particularly preferably 1.0 to 6.0. When the charge equivalent [nitrogen-containing compound / thiourethane resin] is 1.0 or more, the production of the polythiol composition is further promoted. When the charge equivalent [nitrogen-containing compound / thiourethane resin] is 10.0 or less, the nitrogen-containing compound remaining in the reaction mixture can be further suppressed.

[0030] <<Quaternary Ammonium Salts>> The quaternary ammonium salt is not particularly limited, as long as it consists of a quaternary ammonium cation and a counter anion. Suitable examples include tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide (TEAH), tetrabutylammonium hydroxide (TBAOH), benzyltrimethylammonium hydroxide, tetrahexylammonium hydroxide, 2-hydroxyethyltrimethylammonium hydroxide, hexadecyltrimethylammonium hydroxide, N,N,N-tris(polyoxyethylene)-N-methylammonium hydroxide, trimethylphenylammonium hydroxide, 3-(trifluoromethyl)phenyltrimethylammonium hydroxide, tetrabutylammonium fluoride (TBAF), tetrabutylammonium chloride (TBACl), tetrabutylammonium bromide (TBAB), tetrabutylammonium iodide (TBAI), benzyltriethylammonium hydroxide, hexadecyltrimethylammonium hydroxide, benzethonium hydroxide, benzalkonium hydroxide, and cetylpyridinium hydroxide.

[0031] When the reaction system contains an alcohol as an optional component, as shown in the following reaction formula (1), the left side of "quaternary ammonium salt (quaternary ammonium cation NR ４ ＋ and counter anion X - ) and "Alcohol R ３ OH" reacts and the right side of "NR ４ ＋ " "R ３ O - As shown in the following reaction formula (2), the generated "R ３ O - It is presumed that "R" promotes the decomposition of the thiourethane resin. ３ O - It is presumed that if "R" is produced in excess, a side reaction will proceed. Therefore, in the present invention, water is added to the alcohol as an optional component to adjust the alcohol concentration, thereby ３ O -" is prevented from being excessively produced, thereby suppressing side reactions and enabling the production of a polythiol composition in a short reaction time. In addition, when the reaction system does not contain an alcohol as an optional component, the produced "X" is reacted with the alcohol as shown in the following reaction formula (X). - It is presumed that this promotes the decomposition of thiourethane resin.

[0032]

[0033]

[0034]

[0035] The content of the quaternary ammonium salt in the reaction system in the reaction step is not particularly limited, but from the viewpoint of further improving the reactivity with the thiourethane resin, it is preferably 1 to 40 mass%, more preferably 2 to 30 mass%, and particularly preferably 3 to 20 mass%.

[0036] (Charge amount of quaternary ammonium salt) In the reaction step, the charge mass ratio of the quaternary ammonium salt to the thiourethane resin (i.e., charge mass ratio [quaternary ammonium salt / thiourethane resin]) can be adjusted as appropriate, but is preferably 0.1 to 10, more preferably 0.2 to 9, and particularly preferably 0.4 to 6. When the charge mass ratio [quaternary ammonium salt / thiourethane resin] is 0.1 or more, the production of the polythiol composition is further promoted. When the charge mass ratio [quaternary ammonium salt / thiourethane resin] is 10 or less, the remaining quaternary ammonium salt in the reaction mixture can be further suppressed.

[0037] In the reaction step, the number of millimoles of the quaternary ammonium salt charged per 1 g of the thiourethane resin is preferably 1.0 to 100.0 mmol / g, more preferably 2.0 to 50.0 mmol / g, and particularly preferably 3.0 to 25.0 mmol / g.

[0038] In the reaction step, the charge equivalent of the quaternary ammonium salt relative to the thiourethane resin (charge equivalent [quaternary ammonium salt / thiourethane resin]) is preferably 1.0 to 10.0, more preferably 1.0 to 8.0, and particularly preferably 1.0 to 6.0. When the charge equivalent [quaternary ammonium salt / thiourethane resin] is 1.0 or more, the production of the polythiol composition is further promoted. When the charge equivalent [quaternary ammonium salt / thiourethane resin] is 10.0 or less, the residual quaternary ammonium salt in the reaction mixture can be further suppressed. Here, the charge equivalent of the quaternary ammonium salt relative to the thiourethane resin (charge equivalent [quaternary ammonium salt / thiourethane resin]) refers to the ratio of the number of quaternary ammonium cations in the charged quaternary ammonium salt to the total number of thiourethane bonds in the charged thiourethane resin.

[0039] (Quaternary ammonium cation) The quaternary ammonium cation is NR ４ ＋ All four R's may be the same group, or three of the four R's may be the same group, and the remaining one of the four R's may be a group different from the same group.

[0040] Quaternary ammonium cations (NR ４ ＋ Specific examples of the ammonium ion include a tetramethylammonium ion (all four R's are methyl groups), a tetraethylammonium ion (all four R's are ethyl groups), a tetrabutylammonium ion (all four R's are butyl groups), and a benzyltrimethylammonium ion (three of the four R's are methyl groups and the remaining one is a benzyl group).

[0041] Quaternary ammonium cation NR ４ ＋ The four Rs in the formula (I) are not particularly limited, and are, for example, each independently a group selected from the group consisting of an alkyl group, an aromatic group, a heteroaryl group, and an ether-containing group.

[0042] The alkyl group is not particularly limited, but preferably has 1 to 20 carbon atoms and is linear, branched, or cyclic. Here, the alkyl group may be a substituted alkyl group having a substituent, or an unsubstituted alkyl group having no substituent. Examples of the substituent include a nitro group and a hydroxy group. Note that the number of carbon atoms in an alkyl group refers to the number of carbon atoms in an unsubstituted alkyl group, and does not include the number of carbon atoms in a substituted alkyl group. Specific examples of unsubstituted alkyl groups having no substituent include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, and a heptyl group.

[0043] The aromatic group is not particularly limited, but preferably has 4 to 20 carbon atoms. Here, the aromatic group may be a substituted aromatic group having a substituent, or an unsubstituted aromatic group having no substituent. Examples of the substituent include a methyl group, a nitro group, and a hydroxy group. Note that the number of carbon atoms in the aromatic group refers to the number of carbon atoms in the unsubstituted aromatic group, and does not include the number of carbon atoms in the substituted substituent. Specific examples of unsubstituted aromatic groups having no substituent include a benzyl group, a phenyl group, a naphthyl group, a phenethyl group, an anthryl group, a pyrenyl group, and a thiophenyl group.

[0044] The heteroaryl group is not particularly limited, but preferably has 4 to 20 carbon atoms. Here, the heteroaryl group may be a substituted heteroaryl group having a substituent, or an unsubstituted heteroaryl group having no substituent. Examples of the substituent include a methyl group, a nitro group, and a hydroxy group. The number of carbon atoms in a heteroaryl group refers to the number of carbon atoms in the unsubstituted heteroaryl group, and does not include the number of carbon atoms in the substituted heteroaryl group. Specific examples of unsubstituted unsubstituted heteroaryl groups include those obtained by removing one hydrogen atom from a carbon or nitrogen atom of a single ring or ring assembly selected from pyrrole, imidazole, pyrazole, triazole, furan, thiophene, thiazole, isothiazole, oxazole, isoxazole, oxadiazole, thiadiazole, pyridine, pyrazine, pyridazine, pyrimidine, triazine, bipyrrole, terpyrrole, bithiophene, terthiophene, bipyridine, and terpyridine. a fused heteroaryl group that is a monovalent residue obtained by removing one hydrogen atom on a carbon atom or nitrogen atom of a compound selected from indole, carbazole, imidazole, benzimidazole, di(benzimidazo)benzo[1,3,5]triazepine, (benzimidazo)benzimidazole, (benzimidazo)phenanthridine, (benzoindolo)benzazepine, dibenzofuran, and dibenzothiophene; and the like.

[0045] The ether-containing group is not particularly limited, but preferably has 2 to 20 carbon atoms. Here, the ether-containing group may be a substituted ether-containing group having a substituent, or an unsubstituted ether-containing group having no substituent. Examples of the substituent include a methyl group, a nitro group, and a hydroxy group. Note that the number of carbon atoms in the ether-containing group refers to the number of carbon atoms in the unsubstituted ether-containing group, and does not include the number of carbon atoms in the substituted substituent. Specific examples of unsubstituted, unsubstituted ether-containing groups include, for example, polyoxyalkylene groups, polyglycerin groups, tetrahydrofuranyl groups, and benzofuranyl groups.

[0046] (Counter anion (counter ion)) Counter anion X － The cations are not particularly limited, but include halogen ions such as fluorine ions, chlorine ions, bromine ions, and iodine ions; OR ions such as hydroxide ions; ２－ These may be used alone or in combination of two or more. ２ represents a hydrogen atom or an alkyl group having 1 to 12 carbon atoms. Among these, hydroxide ions are preferred from the viewpoint of leaving ability.

[0047] <<Amine Compound>> The amine compound is not particularly limited, and examples thereof include primary amines, secondary amines, and tertiary amines. These may be used alone or in combination of two or more. Among these, primary amines and secondary amines are preferred from the viewpoint of suppressing side reactions. The amine compound may or may not be a cyclic amine.

[0048] The amine compound is preferably an amine compound containing at least one of an amino group and a monoalkylamino group, and in which the total number of amino groups and monoalkylamino groups is 1 to 6 (preferably 1 to 3, more preferably 1 or 2). From the viewpoint of further improving the reactivity with the thiourethane resin, the molecular weight of the amine compound is preferably 1,000 or less, more preferably 500 or less, even more preferably 300 or less, and even more preferably 200 or less. The lower limit of the molecular weight of the amine compound is, for example, 45 or more, preferably 59 or more, and more preferably 60 or more. The molecular weight of the amine compound is not particularly limited, but is preferably 45 to 1,000, more preferably 59 to 500, even more preferably 60 to 300, and even more preferably 60 to 200. Specific examples of the amine compound include alkylamines having 2 to 10 carbon atoms; aralkylamines having 7 to 10 carbon atoms such as benzylamine; dialkylamines having 2 to 10 carbon atoms such as di-n-butylamine; alkyldiamines having 2 to 10 carbon atoms such as ethylenediamine and bis(2-aminoethyl)ether; alkyltriamines having 2 to 10 carbon atoms such as bis(2-aminoethyl)amine; hydroxyalkylamines having 2 to 10 carbon atoms such as monoethanolamine; bis(hydroxyalkyl)amines having 2 to 10 carbon atoms such as bis(hydroxyethyl)amine; cyclic amines having 2 to 10 carbon atoms such as diazabicycloundecene (DBU) and morpholine; and alkyl(hydroxyalkyl)amines having 2 to 10 carbon atoms such as methylethanolamine and isopropylethanolamine.

[0049] The content of the amine compound in the reaction system in the reaction step is not particularly limited, but from the viewpoint of further improving the reactivity with the thiourethane resin, it is preferably 1 to 40 mass%, more preferably 2 to 30 mass%, and particularly preferably 3 to 20 mass%.

[0050] (Charge Amount of Amine Compound) In the reaction step, the charge mass ratio of the amine compound to the thiourethane resin (i.e., charge mass ratio [amine compound / thiourethane resin]) can be adjusted as appropriate, but is preferably 0.1 to 10, more preferably 0.2 to 9, and particularly preferably 0.3 to 6. When the charge mass ratio [amine compound / thiourethane resin] is 0.1 or more, the production of the polythiol composition is further promoted. When the charge mass ratio [amine compound / thiourethane resin] is 10 or less, the amine compound remaining in the reaction mixture can be further suppressed.

[0051] In the reaction step, the number of millimoles of the amine compound charged per 1 g of the thiourethane resin is preferably 1.0 to 100.0 mmol / g, more preferably 2.0 to 50.0 mmol / g, and particularly preferably 3.0 to 25.0 mmol / g.

[0052] In the reaction step, the charge equivalent of the amine compound relative to the thiourethane resin (charge equivalent [amine compound / thiourethane resin]) is preferably 1.0 to 10.0, more preferably 1.0 to 8.0, and particularly preferably 1.0 to 6.0. When the charge equivalent [amine compound / thiourethane resin] is 1.0 or more, the production of the polythiol composition is further promoted. When the charge equivalent [amine compound / thiourethane resin] is 10.0 or less, the remaining amine compound in the reaction mixture can be further suppressed.

[0053] (Primary Amine) Specific examples of primary amines include benzylamine, ethylenediamine, bis(2-aminoethyl)ether, bis(2-aminoethyl)amine, monoethanolamine, aniline, and phenethylamine. When the reaction system further contains an alcohol as an optional component, the primary amine reacts with the alcohol as an optional component to form an alkoxide (R ３ O － ), but as shown in the following formula (4), the primary amine itself acts as a base and participates in the nucleophilic reaction, so that the alkoxide (R ３ O －It is presumed that this prevents excessive production of hydroxybenzoates and inhibits side reactions.

[0054]

[0055]

[0056] (Secondary Amine) Specific examples of secondary amines include di-n-butylamine, bis(hydroxyethyl)amine, methylethanolamine, isopropylethanolamine, diphenylamine, etc. When the reaction system further contains an alcohol as an optional component, the secondary amine reacts with the alcohol as an optional component to form an alkoxide (R ３ O － ), but since the secondary amine itself acts as a base and participates in the nucleophilic reaction as shown in the following formula (6), an alkoxide (R ３ O － It is presumed that this prevents excessive production of hydroxybenzoates and inhibits side reactions.

[0057]

[0058]

[0059] (Tertiary Amine) Specific examples of tertiary amines include N,N-dimethylethanolamine, triethylamine, and triisobutylamine.

[0060] When the reaction system further contains an optional alcohol, the optional alcohol (R ３ OH) and tertiary amines (NR ４ R ５ R ６ The reaction system using the reaction formula (7) is represented by the right side of "R ３ O － In order to produce ", the temperature must be raised to shift the reaction equilibrium to the right.

[0061]

[0062] (Cyclic Amine) Specific examples of cyclic amines include diazabicycloundecene (DBU), morpholine, and 1,4-diazabicyclo[2,2,2]octane.

[0063] <Water> The content of water in the reaction system in the reaction step is not particularly limited, but from the viewpoint of further improving the reactivity with the thiourethane resin, it is preferably 2 to 50 mass%, more preferably 3 to 40 mass%, even more preferably 4 to 35 mass%, still more preferably 10 to 35 mass%, still more preferably 15 to 35 mass%, and particularly preferably 20 to 35 mass%.

[0064] (Amount of Water Charged) In the reaction step, the charge mass ratio of water to the thiourethane resin (i.e., charge mass ratio [water / thiourethane resin]) can be adjusted as appropriate, but is preferably 0.1 to 10, more preferably 0.2 to 9, and particularly preferably 0.3 to 6. When the charge mass ratio [water / thiourethane resin] is 0.1 or more, the production of the polythiol composition is further promoted. When the charge mass ratio [water / thiourethane resin] is 10 or less, the residual water in the reaction mixture can be further suppressed.

[0065] In the reaction step, the number of millimoles of water charged per 1 g of thiourethane resin is preferably 1.0 to 200.0 mmol / g, more preferably 2.0 to 150.0 mmol / g, and particularly preferably 3.0 to 130.0 mmol / g.

[0066] In the reaction step, the charge equivalent of water relative to the thiourethane resin (charge equivalent [water / thiourethane resin]) is preferably 1.0 to 10.0, more preferably 1.0 to 8.0, and particularly preferably 1.0 to 6.0. When the charge equivalent [water / thiourethane resin] is 1.0 or more, the production of the polythiol composition is further promoted. When the charge equivalent [water / thiourethane resin] is 10.0 or less, the residual water in the reaction mixture can be further suppressed.

[0067] In the present invention, the reaction system contains water, which is a more environmentally friendly solvent than organic solvents, and this may lead to the development of environmentally friendly chemical processes in the future, and purification treatment is easy.

[0068] <Optional Components> The optional components are not particularly limited, and examples thereof include alcohols, reaction solvents, and bases other than nitrogen-containing compounds such as sodium hydroxide.

[0069] <<Alcohol>> In the reaction step, it is preferable to react at least one alcohol as an optional component with the thiourethane resin. The optional alcohol is thought to function as a decomposing agent for the thiourethane resin. As the optional alcohol in the reaction system of the reaction step, known alcohols can be used without particular limitation. The optional alcohol in the reaction system of the reaction step (i.e., the alcohol that may be reacted with the thiourethane resin) may be only one type or two or more types. The optional alcohol in the reaction system of the reaction step may be a monoalcohol containing only one hydroxy group or a polyol containing two or more hydroxy groups. The optional alcohol in the reaction system of the reaction step may be any of primary alcohols such as ethanol, n-propanol, monoethanolamine, etc.; secondary alcohols such as isopropanol (2-propanol), etc.; and tertiary alcohols such as t-butyl alcohol. However, from the viewpoint of reaction in a low temperature range, lower alcohols such as methanol and ethanol are preferred.

[0070] Specific examples of the alcohol, which is an optional component in the reaction system of the reaction step, are not particularly limited, and include, for example, methanol, ethanol, t-butyl alcohol, isopropanol (2-propanol), n-propanol, propylene glycol, ethylene glycol, diethylene glycol, benzyl alcohol, phenethyl alcohol, 2-octanol, 2-ethyl-1-hexanol, 1-decanol, 1-nonanol, 1-octanol, 1-heptanol, 1-hexanol, 1-pentanol, propylene glycol, ethylene glycol, and monoethanolamine. These may be used alone or in combination of two or more. Among these, from the viewpoint of miscibility with the aqueous nitrogen-containing compound solution, it is preferable to include one or more water-miscible alcohols. Examples of water-miscible alcohols include methanol, ethanol, t-butyl alcohol, isopropanol (2-propanol), n-propanol, propylene glycol, ethylene glycol, diethylene glycol, and monoethanolamine. In this specification, the term "miscible" means that "10 g or more of an alcohol compound can be dissolved in 1 kg of water at room temperature (25° C.) and normal pressure (1 atmosphere)."

[0071] From the viewpoint of further improving the reactivity with the thiourethane resin, the molecular weight of the alcohol, which is an optional component in the reaction step, is preferably 1,000 or less, more preferably 500 or less, even more preferably 300 or less, and particularly preferably 200 or less. The lower limit of the molecular weight of the alcohol, which is an optional component in the reaction system of the reaction step, is, for example, 30 or more. The molecular weight of the alcohol, which is an optional component in the reaction step, is not particularly limited, but is preferably 30 to 1,000, more preferably 30 to 500, even more preferably 30 to 300, and particularly preferably 30 to 200.

[0072] The alcohol, which is an optional component in the reaction step, preferably contains an alcohol having a boiling point of 60° C. to 250° C. (hereinafter also referred to as “alcohol A”). In this specification, the boiling point means the boiling point under 1 atmosphere (101,325 Pa).

[0073] The proportion of alcohol A in the total amount of alcohols, which are optional components in the reaction system of the reaction step, is preferably 50% by mass to 100% by mass, more preferably 60% by mass to 100% by mass, and particularly preferably 80% by mass to 100% by mass.

[0074] The content of the alcohol, which is an optional component in the reaction system of the reaction step, is not particularly limited, but from the viewpoint of further improving the reactivity with the thiourethane resin, it is preferably 1 to 90 mass%, more preferably 2 to 80 mass%, and particularly preferably 3 to 70 mass%.

[0075] The preferred amounts of alcohols, which are optional components in the reaction system of the reaction step, are shown below. The preferred amounts also apply to the preferred amount of alcohol A (i.e., alcohol having a boiling point of 60°C to 250°C).

[0076] (Charge amount of alcohol, which is an optional component in the reaction system of the reaction step) In the reaction step, the charge mass ratio of the alcohol, which is an optional component, to the thiourethane resin (i.e., the charge mass ratio [alcohol / thiourethane resin]) can be adjusted as appropriate, but is preferably 0.10 to 20, more preferably 0.30 to 15, and particularly preferably 0.40 to 10. When the charge mass ratio [alcohol / thiourethane resin] is 0.10 or more, the production of the polythiol composition is further promoted. When the charge mass ratio [alcohol / thiourethane resin] is 20 or less, the remaining alcohol in the reaction mixture can be further suppressed.

[0077] In the reaction step, the number of millimoles of the alcohol, which is an optional component, charged per 1 g of thiourethane resin is preferably 1.0 to 100.0 mmol / g, more preferably 3.0 to 90.0 mmol / g, and particularly preferably 5.0 to 85.0 mmol / g.

[0078] In the reaction step, the charge equivalent of the alcohol relative to the thiourethane resin (charge equivalent [alcohol / thiourethane resin]) is preferably 1.0 to 25, more preferably 1.2 to 20, and particularly preferably 1.5 to 15. When the charge equivalent [alcohol / thiourethane resin] is 1.0 or more, the production of the polythiol composition is further promoted. When the charge equivalent [alcohol / thiourethane resin] is 25 or less, the residual alcohol in the reaction mixture can be further suppressed. Here, the charge equivalent of the alcohol relative to the thiourethane resin (charge equivalent [alcohol / thiourethane resin]) means the ratio of the number of hydroxy groups in the charged alcohol to the total number of thiourethane bonds in the charged thiourethane resin.

[0079] (Reaction Solvent) In the reaction step, the thiourethane resin, the nitrogen-containing compound, and the optional alcohol may be reacted in the presence of a reaction solvent. The reaction solvent refers to a reaction solvent other than the optional alcohol and water, and examples thereof include hydrocarbons having 5 to 12 carbon atoms (preferably 6 to 10, more preferably 7 to 9), ethers having 4 to 12 carbon atoms, ketones having 3 to 12 carbon atoms, esters having 4 to 12 carbon atoms, and nitriles having 2 to 12 carbon atoms. These may be used alone or in combination of two or more.

[0080] The hydrocarbon is preferably hexane, heptane, octane, nonane, decane, xylene, mesitylene, or toluene, more preferably heptane, octane, nonane, xylene, mesitylene, or toluene, and particularly preferably xylene or toluene. The ether is preferably diethyl ether, tetrahydrofuran, 2-methyltetrahydrofuran, dimethoxyethane, or 1,4-dioxane, and more preferably dimethoxyethane. The ketone is preferably acetone, methyl ethyl ketone, methyl isobutyl ketone, or 2-octanone, and more preferably methyl isobutyl ketone. The ester is preferably ethyl acetate, butyl acetate, or pentyl acetate, and more preferably pentyl acetate. The nitrile is preferably acetonitrile or propionitrile, and more preferably acetonitrile.

[0081] The content of the reaction solvent in the reaction system in the reaction step is not particularly limited, but from the viewpoint of further improving the reactivity with the thiourethane resin, it is preferably 95% by mass or less, more preferably 90% by mass or less, and particularly preferably 85% by mass or less.

[0082] <Reaction Temperature> The reaction temperature of the thiourethane resin, nitrogen-containing compound, and optional alcohol in the reaction step can be adjusted as appropriate. In the reaction step, the thiourethane resin, nitrogen-containing compound, water, and optional alcohol are preferably reacted under temperature conditions (i.e., reaction temperature) of 15 to 110°C (more preferably 30 to 105°C, particularly preferably 40 to 100°C). When the reaction temperature is 15 to 110°C, the purity of the polythiol component as the main component in the target polythiol composition (i.e., the content of the main component relative to the total amount of the polythiol composition) can be further improved. Furthermore, the reaction step may be carried out under pressurized conditions. When the reaction is carried out under pressurized conditions, the reaction time may be shortened.

[0083] <Reaction Time> The reaction time of the thiourethane resin, nitrogen-containing compound, water, and alcohol as an optional component in the reaction step can be adjusted as appropriate, but is preferably 0.10 to 5.50 hours, more preferably 0.50 to 5.00 hours, even more preferably 1.00 to 4.50 hours, and particularly preferably 1.00 to 4.00 hours.

[0084] <Polythiol Composition> In the present disclosure, a polythiol composition refers to a composition containing at least one polythiol compound, and may contain other components such as a polyisocyanate compound and a polyamine compound. In the present disclosure, the polythiol compound contained in the polythiol composition is also referred to as a "polythiol component." The polythiol composition preferably contains at least one polythiol compound as a main component. Here, "the polythiol composition contains at least one polythiol compound as a main component" means that the total content of the at least one polythiol compound relative to the total amount of the polythiol composition is 50% by mass or more. The total content of the at least one polythiol compound relative to the total amount of the polythiol composition is preferably 60% by mass or more, more preferably 70% by mass or more, and particularly preferably 80% by mass or more.

[0085] The polythiol composition as the target product includes polythiol compositions containing known polythiol compounds.

[0086] The polythiol composition as the target product and the polythiol composition as the raw material for the thiourethane resin as the starting material do not need to be completely identical. However, from the viewpoint of the performance of the thiourethane resin produced from the polythiol composition as the target product, it is preferable that the type of polythiol component as the main component in the polythiol composition as the target product and the type of polythiol component as the main component in the polythiol composition as the raw material are the same. In this case, for example, an optical material B (an optical material containing a thiourethane resin) having performance comparable to that of the optical material A can be produced using cutting powder (thiourethane resin) generated during the production of the optical material A as the raw material.

[0087] The polythiol composition as the target product may have the same polythiol component as the main component and a reduced content of impurities as the polythiol composition as the raw material of the thiourethane resin as the starting material. When the impurity content is reduced in the polythiol composition as the target product, thickening of the polythiol composition is suppressed, which can have the advantage of extending the pot life of the polythiol composition.

[0088] The use of the polythiol composition as the target product is not particularly limited. The polythiol composition as the target product can be used, for example, in the production of a thiourethane resin. Specific uses of the polythiol composition as the target product include a polythiol composition for the production of optical materials (e.g., eyeglass lenses). In other words, a specific example of the method for producing a polythiol composition of the present disclosure is a method for producing a polythiol composition for the production of optical materials. In this specific example, when cutting powder containing a thiourethane resin generated during the production of an optical material is used as the starting material, effective utilization (i.e., recycling) of the materials (thiourethane resin and its raw material, the polythiol composition) is effectively realized. Furthermore, in the reaction step of the present disclosure, a polythiol composition is obtained by reacting a thiourethane resin with a nitrogen-containing compound in the presence of water, thereby obtaining a polythiol composition with a higher purity of the polythiol component as the main component compared to known methods (e.g., a method for obtaining a polythiol composition by reacting a thiourethane resin with sodium hydroxide). Therefore, even when the polythiol composition as the target product is used in the production of an optical material (e.g., a lens), an optical material with good performance can be obtained. The performance of the optical material includes optical properties (for example, refractive index and / or Abbe number), heat resistance, specific gravity, and the like.

[0089] (Polythiol Compound) The polythiol compound is not particularly limited as long as it is a compound containing two or more thiol groups (also known as mercapto groups). For polythiol compounds, the above-mentioned known documents (i.e., JP-A-63-46213, JP-A-2-270859, JP-A-7-252207, WO 2008 / 047626, etc.) can be appropriately referenced.

[0090] The polythiol compound is not particularly limited, and suitable examples thereof include 4-mercaptomethyl-1,8-dimercapto-3,6-dithiaoctane, 4,8-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 4,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 5,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, pentaerythritol tetrakis(2-mercaptoacetate), pentaerythritol tetrakis(3-mercaptopropionate), 2,5-dimercaptomethyl-1,4-dithiane, bis(2-mercaptoethyl)sulfide, and diethylene glycol bis(3-mercaptopropionate) (hereinafter also referred to as "polythiol component A"). These may be used alone or in combination of two or more. The polythiol composition more preferably contains polythiol component A as the main component. In this case, the polythiol composition may contain at least one other component other than polythiol component A (for example, other polythiol compounds, components other than polythiol compounds, etc.).

[0091] The other polythiol compounds are not particularly limited and include, for example, methanedithiol, 1,2-ethanedithiol, 1,2,3-propanetrithiol, tetrakis(mercaptomethylthiomethyl)methane, tetrakis(2-mercaptoethylthiomethyl)methane, tetrakis(3-mercaptopropylthiomethyl)methane, bis(2,3-dimercaptopropyl)sulfide, 2,5-dimercapto-1,4-dithiane, 2,5-dimercaptomethyl-2,5-dimethyl-1,4-dithiane, 1,1,3,3-tetrakis(mercaptomethylthio)propane, 1,1,2,2-tetrakis(mercaptomethylthio)ethane, 4,6-bis(mercaptomethylthio)-1,3-dithiane, etc. These may be used alone or in combination of two or more.

[0092] (Polyisocyanate Compound) The polyisocyanate compound may be any compound containing two or more isocyanate groups. The polyisocyanate compound is not particularly limited, and examples thereof include pentamethylene diisocyanate, hexamethylene diisocyanate, m-xylylene diisocyanate, p-xylylene diisocyanate, isophorone diisocyanate, bis(isocyanatomethyl)cyclohexane, bis(isocyanatocyclohexyl)methane, 2,5-bis(isocyanatomethyl)bicyclo-[2.2.1]-heptane, 2,6-bis(isocyanatomethyl)bicyclo-[2.2.1]-heptane, tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, and phenylene diisocyanate. These compounds may be used alone or in combination of two or more. Among these, m-xylylene diisocyanate, 2,5-bis(isocyanatomethyl)bicyclo-[2.2.1]-heptane, and 2,6-bis(isocyanatomethyl)bicyclo-[2.2.1]-heptane are preferred.

[0093] (Polyamine Compound) The polyamine compound may be any compound containing two or more amino groups. The polyamine compound is not particularly limited, and examples thereof include pentamethylenediamine, hexamethylenediamine, m-xylylenediamine, p-xylylenediamine, isophoronediamine, bis(aminomethyl)cyclohexane, bis(aminocyclohexyl)methane, 2,5-bis(aminomethyl)bicyclo-[2.2.1]-heptane, 2,6-bis(aminomethyl)bicyclo-[2.2.1]-heptane, tolylenediamine, 4,4'-diphenylmethanediamine, and phenylenediamine. These may be used alone or in combination of two or more. Among these, m-xylylenediamine, 2,5-bis(aminomethyl)bicyclo-[2.2.1]-heptane, and 2,6-bis(aminomethyl)bicyclo-[2.2.1]-heptane are preferred.

[0094] (Preferred embodiment of the step of producing a polythiol composition) The step of producing a polythiol composition is preferably a step of reacting a thiourethane resin, a nitrogen-containing compound, and an optional alcohol in the presence of water to produce a polythiol compound and an optional polyamine compound as a polythiol composition. In this preferred embodiment, a decomposition reaction occurs in which the thiourethane resin is decomposed into a polythiol compound and an optional polyamine compound by the alcohol as a decomposing agent. The decomposition reaction is an alcoholysis reaction.

[0095] (Resin Mixture Containing Thiourethane Resin) The step of producing a polythiol composition may be a step of contacting a resin mixture containing a thiourethane resin with a nitrogen-containing compound and an optional alcohol in the presence of water, thereby reacting the thiourethane resin, the nitrogen-containing compound, and the optional alcohol in the resin mixture in the presence of water to produce the polythiol composition.

[0096] The resin mixture containing the thiourethane resin further contains components other than the thiourethane resin, such as resins other than the thiourethane resin and inorganic materials (e.g., glass) for lens production.

[0097] Resins other than thiourethane resins are not particularly limited, and examples thereof include a hybrid material of a thiourethane resin and a urethane resin produced by adding a polyol to the raw materials when producing a thiourethane resin; a hybrid material of a thiourethane resin and a urea resin produced by adding a polyamine compound to the raw materials when producing a thiourethane resin; a polyolefin film that protects the surface of a resin molded product used to produce eyeglass lenses; a hard coat or primer coat that protects the surface of a resin molded product used to produce eyeglass lenses; a polishing agent used when polishing a resin molded product used to produce eyeglass lenses; a resin material for fixing a resin molded product used to cut a resin molded product used to produce eyeglass lenses; a tape or tape glue used to fix a glass mold used to produce a resin molded product used to produce an eyeglass lens; etc. Specific examples of resins other than thiourethane resins are not particularly limited, and suitable examples thereof include polycarbonate resins, polyallyl carbonate resins, acrylic resins, urethane resins, episulfide resins, etc.

[0098] The resin mixture containing the thiourethane resin is preferably recovered during at least one of the processes for manufacturing eyeglass lenses, manufacturing eyeglasses, and disposing of eyeglasses. The processes for manufacturing eyeglass lenses, manufacturing eyeglasses, and disposing of eyeglasses are as described above. The resin mixture containing the thiourethane resin preferably contains cutting powder containing the thiourethane resin.

[0099] (Reaction mixture containing polythiol composition) The step of producing a polythiol composition may be a step of reacting a thiourethane resin, a nitrogen-containing compound, and an optional alcohol in the presence of water to produce a polythiol composition, thereby obtaining a reaction mixture containing the polythiol composition as the target product. The reaction mixture may contain the polythiol composition as the main product produced by alcoholysis, and other components other than the polythiol composition. Examples of other components in the reaction mixture other than the polythiol composition include by-products produced by alcoholysis (e.g., polycarbamate), the reaction solvent described above, residues of raw materials (thiourethane resin, optional alcohol, and / or nitrogen-containing compound), impurities contained in the raw materials, etc.

[0100] [Separation Step] The method for producing a polythiol composition may include a separation step of separating the polythiol composition as the target product from a reaction mixture containing the polythiol composition. The separation method in the separation step is not particularly limited, and includes known methods such as filtration, decantation, extraction, distillation, drying (including drying under reduced pressure), and purification (for example, column chromatography). These may be used alone or in combination of two or more.

[0101] The separation step preferably includes filtering the reaction mixture containing the polythiol composition obtained in the reaction step to obtain a filtrate containing the polythiol composition. According to this embodiment, it is easier to remove solids contained in the reaction mixture.

[0102] The polythiol compound in the polythiol composition can be separated by extraction with an organic solvent or inorganic solvent that can dissolve the polythiol compound. The polythiol compound can be purified by a common purification method such as column purification, distillation purification, recrystallization purification, or salt extraction.

[0103] The polyamine compound in the polythiol composition can be separated by extraction with an organic solvent or inorganic solvent that can dissolve the polyamine compound. The polyamine compound can be purified by a common purification method such as column purification, distillation purification, recrystallization purification, or salt extraction.

[0104] When the step of producing a polythiol composition is the step of producing a polythiol compound and a polyamine compound as described above, the separation step preferably includes at least one of filtering a reaction mixture containing the polythiol compound and a polyamine compound derivative to obtain a filtrate containing the polythiol compound as a filtrate and obtaining a mixture containing the polyamine compound derivative as a residue.

[0105] When the separation step includes obtaining a filtrate containing a polythiol compound as a filtrate, the polythiol compound is separated from the filtrate to obtain a polythiol compound as a polythiol composition. An example of the separation step in this case includes: filtering a reaction mixture containing a polythiol compound and a polyamine compound as a polythiol composition to obtain a filtrate containing a polythiol compound; adding an alkali metal-containing base to the filtrate containing the polythiol compound, followed by addition of water to perform extraction to obtain an aqueous extract containing an alkali metal salt of the polythiol compound; adding an acid to the aqueous extract containing the alkali metal salt of the polythiol compound to obtain an aqueous liquid containing the polythiol compound; adding a hydrocarbon having 5 to 12 carbon atoms as an extraction solvent to the aqueous liquid containing the polythiol compound to perform extraction to obtain an extract containing the polythiol compound; and separating the polythiol compound from the extract containing the polythiol compound. In this example, first, the polythiol compound in the filtrate containing the polythiol compound is converted to an alkali metal salt, and then extraction is performed with water to obtain an aqueous extract containing the alkali metal salt of the polythiol compound. Next, an acid is added to the mixture to convert the alkali metal salt of the polythiol compound back into the polythiol compound. The polythiol compound is extracted from the resulting aqueous liquid containing the polythiol compound using the extraction solvent to obtain an extract containing the polythiol compound. The polythiol compound is separated from the resulting extract containing the polythiol compound. According to this example, even when the filtrate containing the polythiol compound contains a large amount of components other than the polythiol compound, a polythiol compound having a higher purity of the polythiol component as the main component can be obtained.

[0106] The alkali metal in the alkali metal-containing base is not particularly limited, but is preferably sodium, potassium, or lithium, more preferably sodium or potassium. The alkali metal-containing base is not particularly limited, and examples thereof include sodium methoxide, sodium ethoxide, sodium propoxide, sodium hydroxide, potassium hydroxide, and lithium hydroxide. The alkali metal-containing base can be added to the filtrate in the form of an alcohol solution (e.g., methanol solution, ethanol solution), as needed.

[0107] The acid to be added to the aqueous extract containing the alkali metal salt of the polythiol compound is not particularly limited, and examples thereof include hydrochloric acid, carbonic acid, nitric acid, sulfuric acid, acetic acid, formic acid, and oxalic acid.

[0108] The extraction solvent may be one type only or two or more types. Preferred embodiments of the extraction solvent are the same as the preferred embodiments of the reaction solvent described above. However, the reaction solvent and the extraction solvent may be the same or different.

[0109] [Other Steps] The method for producing a polythiol composition may include other steps in addition to the steps described above, as necessary. Examples of other steps include a classification step, a sieving step, a washing step, and a crushing (pulverization) step.

[0110] <Classification Step> The method for producing a polythiol composition may further include a classification step, prior to the reaction step of producing a polythiol composition, of classifying cutting powder containing a thiourethane resin to obtain powder containing a thiourethane resin (i.e., cutting powder with a reduced average particle size) having a smaller average particle size (e.g., number average value of circle-equivalent diameter) than the cutting powder.

[0111] In the reaction step of producing a polythiol composition when this classification step is included, the powder, the nitrogen-containing compound, and the optional alcohol are contacted in the presence of water, thereby reacting the thiourethane resin in the powder, the nitrogen-containing compound, and the optional alcohol in the presence of water. When the production method for a polythiol composition includes a classification step, in the reaction step, the powder consisting of particles with a small particle size (i.e., average particle diameter), the nitrogen-containing compound, and the optional alcohol are contacted in the presence of water, so that the reaction efficiency of the thiourethane resin in the powder, the nitrogen-containing compound, and the optional alcohol can be further improved.

[0112] Examples of the average particle size include the number average particle size. Examples of the particle size include the circle equivalent diameter. Examples of classification methods include sieving, centrifugation, and the like. For an embodiment in which sieving is performed as classification, see the sieving step described below.

[0113] <Sieving step> The method for producing a polythiol composition may include a sieving step in which cutting powder containing a thiourethane resin is sieved to obtain a powder containing a thiourethane resin (i.e., cutting powder that has passed through the sieve) before the reaction step in which the polythiol composition is produced. In the reaction step in which the polythiol composition is produced, the powder, the nitrogen-containing compound, and the optional alcohol are contacted in the presence of water, thereby reacting the thiourethane resin in the powder with the nitrogen-containing compound and the optional alcohol in the presence of water. When the method for producing a polythiol composition includes a sieving step, in the reaction step, the powder consisting of small particles is contacted with the nitrogen-containing compound and the optional alcohol in the presence of water, thereby further improving the reaction efficiency of the thiourethane resin, the nitrogen-containing compound, and the optional alcohol.

[0114] The sieve is not particularly limited. The nominal mesh size of the sieve as specified in JIS Z-8801-1:2019 is, for example, 0.1 to 20 mm, preferably 0.1 to 10 mm, more preferably 0.1 to 5 mm, even more preferably 0.1 to 2 mm, still more preferably 0.3 to 2 mm, and particularly preferably 0.5 to 1.5 mm.

[0115] <Washing Step> The method for producing a polythiol composition may include a washing step in which the thiourethane resin powder (i.e., a powder containing a thiourethane resin) is washed with a hydrocarbon having 5 to 12 carbon atoms as a washing solvent prior to the reaction step in which the polythiol composition is produced. In the reaction step in which the polythiol composition is produced, the powder washed in the washing step is contacted with the nitrogen-containing compound and the optional alcohol in the presence of water, thereby reacting the thiourethane resin in the powder with the nitrogen-containing compound and the optional alcohol in the presence of water. This results in a polythiol composition having a higher purity of the polythiol component as the main component. In particular, when cutting powder containing a thiourethane resin is used as the starting material in the method for producing a polythiol composition, the washing step can effectively remove oil from the cutting machine adhering to the cutting powder, thereby resulting in a polythiol composition having a higher purity of the polythiol component as the main component.

[0116] The hydrocarbon as the washing solvent may be used alone or in combination of two or more. Preferred embodiments of the hydrocarbon as the washing solvent are the same as the preferred embodiments of the hydrocarbon as the reaction solvent described above. However, the reaction solvent and the washing solvent may be the same or different.

[0117] The washing method in the washing step is not particularly limited, and any known method can be used, such as a method in which the washing solvent is added to and mixed with the thiourethane resin powder.

[0118] When the method for producing a polythiol composition includes the sieving step and the washing step, the sieving step and the washing step are preferably performed in this order. In this case, since it is not necessary to wash off the cutting powder that did not pass through the sieve, the amount of washing solvent used can be further reduced.

[0119] <Crushing (Pulverizing) Step> The method for producing a polythiol composition may include a crushing (pulverizing) step of crushing and / or pulverizing the thiourethane resin prior to the reaction step of producing the polythiol composition. The crushing (pulverizing) method in the crushing (pulverizing) step is not particularly limited, and known methods can be applied.

[0120] [Method for Producing Polymerizable Composition] The method for producing a polymerizable composition of the present disclosure includes a step of producing a polythiol composition by the method for producing a polythiol composition of the present disclosure, and a step of mixing a polythiol composition containing at least the produced polythiol composition with a polyisocyanate to obtain a polymerizable composition containing the polythiol composition, the polyisocyanate, and other optional components, and may further include other steps as necessary.

[0121] In the method for producing a polymerizable composition of the present disclosure, in the step of producing a polythiol composition, a polythiol composition is produced using a thiourethane resin (e.g., a thiourethane resin in grinding powder from a thiourethane resin molded body) as a starting material, and in the step of obtaining a polymerizable composition, a polymerizable composition is produced containing the polythiol composition produced above and a polyisocyanate compound. The obtained polymerizable composition can be reused to produce a thiourethane resin. In this way, the method for producing a polymerizable composition achieves effective utilization (i.e., recycling) of materials (i.e., thiourethane resin and its raw material, the polythiol composition).

[0122] Furthermore, as described above, the method for producing a polythiol composition provides a polythiol composition with a high purity of the polythiol component as the main component, compared to known methods (e.g., methods for obtaining a polythiol composition by reacting a thiourethane resin with sodium hydroxide). The polymerizable composition obtained by the method for producing a polymerizable composition can produce a resin with excellent performance properties (e.g., optical properties (e.g., refractive index and / or Abbe number), heat resistance, specific gravity, etc.). Therefore, the polymerizable composition obtained by the method for producing a polymerizable composition of the present disclosure is particularly suitable as a composition for producing a thiourethane resin for optical materials.

[0123] [Step of Producing Polythiol Composition] For the step of producing the polythiol composition, the above-described method of producing the polythiol composition of the present disclosure can be appropriately referred to.

[0124] [Step of Obtaining a Polymerizable Composition] In the step of obtaining a polymerizable composition, at least the polythiol composition and a polyisocyanate compound are mixed to obtain a polymerizable composition containing the polythiol composition and the polyisocyanate compound.

[0125] A preferred embodiment of the polyisocyanate compound used in the step of obtaining the polymerizable composition is the same as the preferred embodiment of the "polyisocyanate compound" explained in the section "polythiol composition."

[0126] In the step of obtaining a polymerizable composition, the mixing ratio of the polythiol composition and the polyisocyanate compound is not particularly limited. In the step of obtaining a polymerizable composition, the ratio of the charged mass of the polythiol composition to the charged mass of the polyisocyanate compound (i.e., charged mass [polythiol composition / polyisocyanate compound]) is preferably 0.10 to 10.0, more preferably 0.20 to 5.00, even more preferably 0.50 to 1.50, and particularly preferably 0.70 to 1.30. Furthermore, the molar ratio of mercapto groups of the polythiol compound contained in the polythiol composition to isocyanato groups of the polyisocyanate compound (mercapto groups / isocyanato groups) is preferably 0.5 to 3.0, more preferably 0.6 to 2.0, and particularly preferably 0.8 to 1.3.

[0127] In the step of obtaining the polymerizable composition, the total charged mass of the polythiol composition and the polyisocyanate compound is not particularly limited, but is preferably 60 mass% or more, more preferably 80 mass% or more, and particularly preferably 90 mass% or more, based on the total amount of the polymerizable composition to be produced.

[0128] In the step of obtaining a polymerizable composition, at least the polythiol composition and the polyisocyanate compound are mixed, but if necessary, the polythiol composition and the polyisocyanate compound may be mixed with other components. Furthermore, in the step of obtaining a polymerizable composition, after mixing at least the polythiol composition and the polyisocyanate compound, other components may be added to the mixture. The other components are not particularly limited, and examples thereof include polymerization catalysts, internal mold release agents, resin modifiers, chain extenders, crosslinking agents, radical scavengers, light stabilizers, UV absorbers, antioxidants, oil-soluble dyes, fillers, adhesion improvers, antibacterial agents, antistatic agents, dyes, fluorescent brighteners, fluorescent pigments, and inorganic pigments.

[0129] <Polymerization catalyst> The polymerization catalyst is not particularly limited, and examples thereof include tertiary amines, inorganic or organic acid salts of tertiary amines, metal compounds such as dimethyltin dichloride, quaternary ammonium salts, organic sulfonic acids, etc. These may be used alone or in combination of two or more.

[0130] <Internal Release Agent> The internal release agent is not particularly limited, and examples thereof include acidic phosphate esters such as phosphate monoesters and phosphate diesters. These may be used alone or in combination of two or more.

[0131] <Resin modifier> The resin modifier is not particularly limited, and examples thereof include episulfides, epoxies, organic acids, organic acid anhydrides, (meth)acrylates, olefins, etc. These may be used alone or in combination of two or more. Note that (meth)acrylate refers to at least one of acrylate and methacrylate.

[0132] In the step of obtaining the polymerizable composition, the above-mentioned components can be mixed in accordance with a conventional method, and the mixing method is not particularly limited.

[0133] [Method for producing resin] The method for producing a resin of the present disclosure includes a step of producing a polymerizable composition by the method for producing a polymerizable composition described above, and a step of curing the polymerizable composition to obtain a resin. The method for producing a resin of the present disclosure may include other steps as necessary. The method for producing a resin of the present disclosure achieves the same effects as the method for producing a polymerizable composition of the present disclosure described above.

[0134] The resin produced by the resin production method of the present disclosure is a thiourethane resin, but in this disclosure it will be referred to simply as a “resin” to distinguish it from the thiourethane resin that is one of the starting materials for the polythiol composition.

[0135] In the resin-producing step, the resin is obtained by curing the polymerizable composition. The curing of the polymerizable composition can be carried out by polymerizing the monomers in the polymerizable composition (specifically, the polythiol composition and the polyisocyanate compound; the same applies hereinafter). As a pretreatment for polymerization, the polymerizable composition may be subjected to filtration, degassing, or other treatments. The polymerization conditions (e.g., polymerization temperature, polymerization time, etc.) for polymerizing the monomers in the polymerizable composition are appropriately set taking into consideration the composition of the composition, the type and amount of monomers used in the composition, the type and amount of polymerization catalyst used in the composition, and, if a mold is used, the properties of the mold, as described below. The polymerization temperature is not particularly limited, but is preferably −50 to 150°C, more preferably 10 to 150°C. The polymerization time is not particularly limited, but is preferably 1 to 200 hours, more preferably 1 to 80 hours.

[0136] In the step of obtaining the resin, the polymer obtained by polymerizing the monomer may be subjected to a treatment such as annealing to obtain the resin. The annealing temperature is not particularly limited, but is preferably 50 to 150°C, more preferably 90 to 140°C, and particularly preferably 100 to 130°C.

[0137] [Method for Producing Molded Article] The method for producing a molded article is a method for producing a molded article containing a resin, and includes the steps of producing a polymerizable composition by the method for producing a polymerizable composition described above, and curing the polymerizable composition to obtain a molded article containing a resin, and may include other steps as necessary. The method for producing a molded article achieves the same effects as the method for producing a polymerizable composition described above.

[0138] In the step of obtaining a molded article containing a resin, the polymerizable composition is cured to obtain a molded article containing a resin. For preferred conditions for curing the polymerizable composition, i.e., for polymerizing the monomers in the polymerizable composition, see the section "Method for producing a resin" as appropriate.

[0139] An example of polymerization in this step is cast polymerization. In cast polymerization, the polymerizable composition is first poured between molds held together by a gasket, tape, or the like. At this time, degassing, filtration, or the like may be performed as necessary. Next, the monomer in the polymerizable composition poured between the molds is polymerized to harden the composition between the molds, thereby obtaining a cured product. The cured product is then removed from the molds to obtain a molded product containing the resin. The polymerization of the monomer may be performed by heating the polymerizable composition. This heating can be performed, for example, using a heating device equipped with a mechanism for heating an object to be heated in an oven, water, or the like.

[0140] [Method for producing optical material, method for producing lens] A method for producing an optical material (e.g., a lens) is a method for producing an optical material (e.g., a lens) including a molded article containing a resin, and includes a step of producing a polymerizable composition by the method for producing a polymerizable composition described above, and a step of curing the polymerizable composition to obtain a molded article containing a resin, and may include other steps as necessary. The method for producing an optical material achieves the same effects as the method for producing a polymerizable composition described above.

[0141] The method for producing an optical material is an application of the method for producing a molded article. For example, in the method for producing a molded article, by appropriately selecting the shape of the mold used in the above-mentioned cast polymerization, a molded article applicable to an optical material (e.g., a lens) can be obtained.

[0142] Examples of optical materials include lenses (for example, eyeglass lenses, camera lenses, and polarized lenses), light-emitting diodes (LEDs), and the like.

[0143] A method for producing an optical material (for example, a lens) may include a step of forming a coating layer on one or both sides of a molded body containing a resin.

[0144] Specific examples of the coating layer include a primer layer, a hard coat layer, an antireflection layer, an antifogging coat layer, an antifouling layer, and a water-repellent layer. Each of these coating layers may be formed alone, or a plurality of coating layers may be formed in a multilayer structure. When coating layers are formed on both sides, the same coating layer may be formed on each side, or different coating layers may be formed on each side.

[0145] The components of the coating layer can be appropriately selected depending on the purpose, and examples of the components of the coating layer include resins such as urethane resins, epoxy resins, polyester resins, melamine resins, and polyvinyl acetal resins; infrared absorbers; light stabilizers; antioxidants; photochromic compounds; dyes; pigments; and antistatic agents.

[0146] For details about eyeglass lenses and coating layers, reference can be made as appropriate to the descriptions in publicly known documents such as International Publication No. WO 2017 / 047745.

[0147] [Polymerizable Composition] The polymerizable composition contains a polythiol composition obtained by the method for producing a polythiol composition and a polyisocyanate compound. The polymerizable composition can be produced by the method for producing a polymerizable composition described above. The polymerizable composition exhibits the same effects as the method for producing a polymerizable composition described above. For preferred embodiments of the polymerizable composition, refer to the method for producing a polymerizable composition described above as appropriate. However, the charged mass [polythiol composition / polyisocyanate compound] should be read as the content mass ratio [polythiol composition / polyisocyanate compound], and the total charged mass of the polythiol composition and the polyisocyanate compound should be read as the total content mass of the polythiol composition and the polyisocyanate compound.

[0148] [Resin, molded body, optical material (e.g., lens)] The resin is a cured product of the polymerizable composition described above. The molded body is a molded body containing the resin described above. The optical material (e.g., lens) is an optical material (e.g., lens) containing the resin described above. The resin, molded body, and optical material (e.g., lens) exhibit the same effects as the method for producing the polymerizable composition described above.

[0149] The resin, molded body, and optical material (e.g., lens) can be produced by the above-mentioned method for producing a resin, method for producing a molded body, and method for producing an optical material (e.g., lens), respectively. For preferred aspects of the resin, molded body, and optical material (e.g., lens), reference can be made to the preferred aspects of the method for producing a resin, method for producing a molded body, and method for producing an optical material (e.g., lens), respectively.

[0150] <Preferred Performance of Resin or Molded Article> The glass transition temperature Tg of the resin (or molded article) is not particularly limited, but from the viewpoint of heat resistance, it is preferably 70°C or higher, more preferably 80°C or higher, and particularly preferably 85°C or higher. The upper limit of the glass transition temperature Tg is not particularly limited, and may be 130°C or lower, 120°C or lower, or 110°C or lower. The glass transition temperature Tg is not particularly limited, and may be preferably 70°C to 130°C, more preferably 80°C to 120°C, and particularly preferably 85°C to 110°C.

[0151] The refractive index (ne) of the resin (or molded product) is not particularly limited, but from the viewpoint of application to optical materials, it is preferably 1.500 or more, more preferably 1.540 or more, and particularly preferably 1.590 or more. The upper limit of the refractive index (ne) is not particularly limited, but is preferably 1.750. The refractive index (ne) is not particularly limited, but is preferably 1.500 to 1.750, more preferably 1.540 to 1.750, and particularly preferably 1.590 to 1.750.

[0152] The Abbe number of the resin (or molded product) is not particularly limited, but from the viewpoint of application to optical materials, it is preferably 28 or more, more preferably 30 or more. The upper limit of the Abbe number is not particularly limited, but is preferably 50, more preferably 45. The Abbe number is not particularly limited, but is preferably 28 to 50, more preferably 30 to 45.

[0153] The specific gravity of the resin (or molded product) is not particularly limited, but from the viewpoint of application to optical materials, it is preferably 1.10 or more, more preferably 1.20 or more. The upper limit of the specific gravity is not particularly limited, but is preferably 1.50, more preferably 1.40. The specific gravity is not particularly limited, but is preferably 1.10 to 1.50, more preferably 1.20 to 1.40.

[0154] In the present disclosure, the examples, contents, and various physical properties of each of the above components may be arbitrarily combined with the items described as examples or preferred ranges in the detailed description of the invention. Furthermore, by adjusting the compositions described in the examples to the compositions described in the detailed description of the invention, the invention can be practiced in the same manner as the examples over the entire range of the claimed composition.

[0155] The present disclosure will be further described below with reference to examples, but the present disclosure is not limited to the embodiments shown in the examples.

[0156] [Production Example 1] <Production of Molded Article Comprising Thiourethane Resin> Into a flask equipped with a stirrer, dimethyltin dichloride (0.0075 parts by mass relative to 100 parts by mass of the total amount of the polyisocyanate compound described below and the polythiol composition described below) serving as a polymerization catalyst, JP-506H (manufactured by Johoku Scientific Industrial Co., Ltd.; acidic phosphate ester) (0.15 parts by mass relative to 100 parts by mass of the total amount of the polyisocyanate compound described below and the polythiol composition described below) serving as a release agent, and m-xylylene diisocyanate (XDI) (49.6 parts by mass) serving as a polyisocyanate compound were added. After stirring until the various additives were fully dissolved, a polythiol composition (50.4 parts by mass) composed mainly of 4,8-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 4,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, and 5,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane was added as the polythiol component and mixed to obtain a transparent, homogeneous solution of a polymerizable composition. This polymerizable composition was degassed at 300 Pa for at least 30 minutes and then filtered through a polytetrafluoroethylene (PTFE) filter with a pore size of 5 μm. The composition was then poured into a mold consisting of a glass mold and a gasket having the desired lens shape. The mold into which the polymerizable composition had been poured was then polymerized in an oven for 24 hours at a temperature ranging from 10°C to 120°C depending on the lens shape. The mold was removed from the oven and demolded to obtain a molded eyeglass lens body made of a resin for optical components, which was then annealed at 120° C. for 2 hours.

[0157] <Production of thiourethane resin powder> The molded article obtained above was cut to produce a lens. The cutting powder generated during this process was collected and passed through a sieve with a nominal mesh size of 1 mm as specified in JIS Z-8801-1:2019 to obtain thiourethane resin powder (i.e., powder containing thiourethane resin) that passed through the sieve.

[0158] [Example 1-1] <Decomposition of thiourethane resin with tetramethylammonium hydroxide and ethanol> (Reaction step) 15.0 g of the thiourethane resin powder obtained in Production Example 1 was weighed, and the entire amount was charged into a 300 mL flask equipped with a condenser, and ethanol (55.3 g; 1.2 mol) as an alcohol, and a 25% by weight tetramethylammonium hydroxide (TMAH) aqueous solution (43.8 g; 0.12 mol) as a quaternary ammonium salt aqueous solution were added thereto, and the mixture was heated and stirred at 40 ° C. (reaction temperature) for 3.00 hours (reaction time) to obtain a reaction mixture containing a polythiol composition (reaction step). The content of water (43.8 × 0.75) in the reaction system (15.0 + 55.3 + 43.8) was 28.8% by weight (43.8 × 0.75 / (15.0 + 55.3 + 43.8) × 100).

[0159] (Separation step) The reaction mixture obtained in the above reaction step was cooled to room temperature, and then solids were removed by filtration. To the obtained filtrate, toluene (45.0 g) was added as a separation solvent. The obtained liquid was washed twice with 100 mL of 1 M hydrochloric acid to remove excess tetramethylammonium hydroxide (TMAH), and then washed twice with 100 mL of water to remove excess hydrochloric acid. To the obtained liquid, 28 mass% sodium methoxide methanol solution (16.4 g; 0.085 mol) was added and stirred. 200.0 g of water was added to extract the soluble components, and the resulting aqueous extract was washed twice with 45.0 g of toluene, and then 21 g of 1 M hydrochloric acid was added and stirred. The soluble components were extracted from the obtained aqueous liquid with 200.0 g of toluene, and the resulting extract was washed twice with 100 mL of water and separated to obtain a toluene solution of a polythiol composition. From the resulting toluene solution, highly polar by-products were removed using a silica gel column, and then the toluene was distilled off using a rotary evaporator. The resulting mixture was subjected to removal of low-boiling point components using a vacuum pump and filtration using a 1-micron PTFE membrane filter, in that order, to obtain 3.1 g (yield: 41 mass%) of a polythiol composition mainly composed of 4,8-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 4,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, and 5,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane (i.e., polythiol components) (these are the separation steps).

[0160] [Example 1-2] <Decomposition of thiourethane resin by benzylamine (primary amine) and ethanol> (reaction step) 15.0 g of the thiourethane resin powder obtained in Production Example 1 was weighed, and the entire amount was charged into a 300 mL flask equipped with a condenser, and benzylamine (12.9 g; 0.12 mol) as an amine compound, ethanol (55.3 g; 0.12 mol) as an alcohol, and pure water (18.0 g) were added thereto, and the mixture was heated and stirred at 80 ° C. (reaction temperature) for 2.75 hours (reaction time) to obtain a reaction mixture containing a polythiol composition (reaction step). The content of water (18.0) in the reaction system (15.0 + 55.3 + 12.9 + 18.0) was 17.8% by mass (18.0 / (15.0 + 55.3 + 12.9 + 18.0) × 100). (Separation Step) The reaction mixture obtained in the above reaction step was cooled to room temperature, and then solids were removed by filtration. Toluene (50.0 g) was added as a separation solvent to the obtained filtrate. The obtained liquid was washed twice with 100 mL of 1 M hydrochloric acid to remove excess benzylamine, and then washed twice with 100 mL of water to remove excess hydrochloric acid. From the obtained toluene solution, highly polar by-products were removed using a silica gel column, and then the toluene was distilled off using a rotary evaporator. The obtained mixture was subjected to removal of low-boiling point components using a vacuum pump and filtration through a 1-micron PTFE membrane filter in this order, thereby obtaining 3.2 g (yield: 42 mass%) of a polythiol composition mainly composed of 4,8-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 4,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, and 5,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane (i.e., polythiol components) (these are the separation steps).

[0161] [Example 1-3] <Decomposition of thiourethane resin with methylethanolamine (secondary amine) and ethanol> In Example 1-2, instead of using benzylamine (12.9 g; 0.12 mol) as the primary amine in the reaction step, methylethanolamine (9.0 g; 0.12 mol) as the secondary amine and 18.0 g of pure water were used, and the reaction time was changed to 3.25 hours. The reaction step and separation step were carried out in the same manner as in Example 1-2. However, in the separation step, it was not the excess benzylamine but the excess secondary amine that was removed by washing twice with 100 mL of 1 M hydrochloric acid. As a result, 2.9 g (yield: 38% by mass) of a polythiol composition was obtained. The content of water (18.0) in the reaction system (15.0+55.3+9.0+18.0) was 18.5 mass% (18.0 / (15.0+55.3+9.0+18.0)×100).

[0162] [Example 1-4] <Decomposition of thiourethane resin with N,N-dimethylethanolamine (tertiary amine) and ethanol> In Example 1-1, instead of using a 25% by mass tetramethylammonium hydroxide (TMAH) aqueous solution (43.8 g; 0.12 mol) as the quaternary ammonium salt aqueous solution in the reaction step, N,N-dimethylethanolamine (10.7 g; 0.12 mol) as the tertiary amine and 18.0 g of pure water were used, the reaction temperature was changed to 80 ° C., and the reaction time was changed to 3.50 hours. Except for this, the reaction step and separation step were carried out in the same manner as in Example 1-1. However, in the separation step, it was not the excess tetramethylammonium hydroxide (TMAH) but the excess tertiary amine that was removed by washing twice with 100 mL of 1 M hydrochloric acid. As a result, 2.4 g (yield: 32% by mass) of a polythiol composition was obtained. The content of water (32.9) in the reaction system (15.0 + 55.3 + 10.7 + 32.9) was 18.2 mass% (18.0 / (15.0 + 55.3 + 10.7 + 18.0) × 100).

[0163] Example 1-5 Decomposition of Thiourethane Resin with Diazabicycloundecene (DBU) and Ethanol The reaction step and separation step were carried out in the same manner as in Example 1-1, except that in the reaction step, instead of using a 25% by mass aqueous solution of tetramethylammonium hydroxide (TMAH) (43.8 g; 0.12 mol) as the quaternary ammonium salt aqueous solution, diazabicycloundecene (DBU) (18.3 g; 0.12 mol) as the cyclic amine and 18.0 g of pure water were used, and the reaction time was changed to 3.50 hours. However, in the separation step, it was not excess tetramethylammonium hydroxide (TMAH) but excess diazabicycloundecene (DBU) that was removed by washing twice with 100 mL of 1 M hydrochloric acid. As a result, 1.3 g (yield: 17% by mass) of a polythiol composition was obtained. The content of water (18.0) in the reaction system (15.0+55.3+18.3+18.0) was 16.8 mass% (18.0 / (15.0+55.3+18.3+18.0)×100).

[0164] [Example 2] <Decomposition of thiourethane resin by monoethanolamine> (reaction step) 10.2 g of the thiourethane resin powder obtained in Production Example 1 was weighed, and the entire amount was placed in a 300 mL flask equipped with a condenser, and monoethanolamine (5.0 g; 0.081 mol) as an amine compound and alcohol, and toluene (120.0 g) and pure water (12.0 g) as a reaction solvent were added thereto, and the mixture was heated and stirred at 100 ° C. (reaction temperature) for 2.75 hours (reaction time) to obtain a reaction mixture containing a polythiol composition (reaction step). The content of water (12.0) in the reaction system (10.2 + 5.0 + 120.0 + 12.0) was 8.2 mass% (12.0 / (10.2 + 5.0 + 120.0 + 12.0) × 100).

[0165] (Separation Step) The reaction mixture obtained in the above reaction step was cooled to room temperature, and then solids were removed by filtration. The obtained filtrate was washed twice with 50 mL of 1 M hydrochloric acid to remove excess monoethanolamine, and then washed twice with 100 mL of water to remove excess hydrochloric acid. From the obtained toluene solution, highly polar by-products were removed using a silica gel column, and then the toluene was distilled off using a rotary evaporator. The obtained mixture was subjected to removal of low-boiling point components using a vacuum pump and filtration through a 1-micron PTFE membrane filter in this order, thereby obtaining 2.6 g (yield: 52 mass%) of a polythiol composition mainly composed of 4,8-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 4,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, and 5,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane (i.e., polythiol components) (these are the separation steps).

[0166] [Example 3-1] <Decomposition of thiourethane resin with tetramethylammonium hydroxide and methanol> In Example 1-1, instead of using ethanol (55.3 g; 1.2 mol) in the reaction step, methanol (38.4 g; 1.2 mol) was used, the reaction time was 2.75 hours, and the reaction temperature was 60 ° C. The reaction step and separation step were carried out in the same manner as in Example 1-1. As a result, 3.9 g (yield: 51% by mass) of a polythiol composition was obtained. The content of water (43.8 × 0.75) in the reaction system (15.0 + 38.4 + 43.8) was 33.8% by mass (43.8 × 0.75 / (15.0 + 38.4 + 43.8) × 100).

[0167] [Example 3-2] <Decomposition of thiourethane resin with benzylamine (primary amine) and methanol> In Example 1-2, instead of using ethanol (55.3 g; 1.2 mol), methanol (38.4 g; 1.2 mol) was used in the reaction step, the reaction time was 2.50 hours, and the reaction temperature was 60 ° C., except that the reaction step and separation step were carried out in the same manner as in Example 1-2. As a result, 3.6 g (yield: 48% by mass) of a polythiol composition was obtained. The content of water (18.0) in the reaction system (15.0 + 38.4 + 12.9 + 18.0) was 21.4% by mass (18.0 / (15.0 + 38.4 + 12.9 + 18.0) × 100).

[0168] [Example 3-3] <Decomposition of thiourethane resin with methylethanolamine (secondary amine) and methanol> In Example 1-3, instead of using ethanol (55.3 g; 1.2 mol), methanol (38.4 g; 1.2 mol) was used in the reaction step, the reaction time was 3.00 hours, and the reaction temperature was 60 ° C., except that the reaction step and separation step were carried out in the same manner as in Example 1-3. As a result, 3.1 g (yield: 41% by mass) of a polythiol composition was obtained. The content of water (18.0) in the reaction system (15.0 + 38.4 + 9.0 + 18.0) was 23.0% by mass (18.0 / (15.0 + 38.4 + 9.0 + 18.0) × 100).

[0169] [Example 3-4] <Decomposition of thiourethane resin with N,N-dimethylethanolamine (tertiary amine) and methanol> In Example 1-4, instead of using ethanol (55.3 g; 1.2 mol), methanol (38.4 g; 1.2 mol) was used in the reaction step, the reaction time was 3.00 hours, and the reaction temperature was 60 ° C., except that the reaction step and separation step were carried out in the same manner as in Example 1-4. As a result, 2.9 g (yield: 38% by mass) of a polythiol composition was obtained. The content of water (18.0) in the reaction system (15.0 + 38.4 + 10.7 + 18.0) was 21.9% by mass (18.0 / (15.0 + 38.4 + 10.7 + 18.0) × 100).

[0170] [Examples 3-5] <Decomposition of thiourethane resin with diazabicycloundecene (DBU) and methanol> In Example 1-5, instead of using ethanol (55.3 g; 1.2 mol), methanol (38.4 g; 1.2 mol) was used in the reaction step, the reaction time was 3.25 hours, and the reaction temperature was 60°C. The reaction step and separation step were carried out in the same manner as in Example 1-5. As a result, 1.6 g of a polythiol composition was obtained (yield: 21% by mass). The content of water (18.0) in the reaction system (15.0 + 38.4 + 18.3 + 18.0) was 20.0% by mass (18.0 / (15.0 + 38.4 + 18.3 + 18.0) × 100).

[0171] [Example 4-1] <Decomposition of thiourethane resin with tetramethylammonium hydroxide and isopropanol> The reaction step and separation step were carried out in the same manner as in Example 1-1, except that isopropanol (2-propanol) (72.1 g; 1.2 mol) was used instead of ethanol (55.3 g; 1.2 mol) in the reaction step in Example 1-1. As a result, 2.7 g of a polythiol composition was obtained (yield: 36% by mass). The content of water (43.8 × 0.75) in the reaction system (15.0 + 72.1 + 43.8) was 25.1% by mass (43.8 × 0.75 / (15.0 + 72.1 + 43.8) × 100).

[0172] [Example 4-2] <Decomposition of thiourethane resin with benzylamine (primary amine) and isopropanol> In Example 1-2, instead of using ethanol (55.3 g; 1.2 mol) and pure water (18.0 g) in the reaction step, isopropanol (2-propanol) (72.1 g; 1.2 mol) and pure water (72.0 g) were used, and the reaction temperature was 100 ° C., except that the reaction step and separation step were carried out in the same manner as in Example 1-2. As a result, 3.4 g of a polythiol composition was obtained (yield: 45% by mass). The content of water (72.0) in the reaction system (15.0 + 72.1 + 12.9 + 72.0) was 41.9% by mass (72.0 / (15.0 + 72.1 + 12.9 + 72.0) × 100).

[0173] [Example 4-3] <Decomposition of thiourethane resin with methylethanolamine (secondary amine) and isopropanol> In Example 1-3, instead of using ethanol (55.3 g; 1.2 mol) and pure water (18.0 g) in the reaction step, isopropanol (2-propanol) (72.1 g; 1.2 mol) and pure water (90.0 g) were used, and the reaction temperature was 100 ° C., except that the reaction step and separation step were carried out in the same manner as in Example 1-3. As a result, 2.2 g of a polythiol composition was obtained (yield: 29% by mass). The content of water (90.0) in the reaction system (15.0 + 72.1 + 9.0 + 90.0) was 48.4% by mass (90.0 / (15.0 + 72.1 + 9.0 + 90.0) × 100).

[0174] [Example 4-4] <Decomposition of thiourethane resin with N,N-dimethylethanolamine (tertiary amine) and isopropanol> In Example 1-4, instead of using ethanol (55.3 g; 1.2 mol) and pure water (18.0 g) in the reaction step, isopropanol (2-propanol) (72.1 g; 1.2 mol) and pure water (54.0 g) were used, the reaction time was 3.25 hours, and the reaction temperature was 100 ° C. Except for this, the reaction step and separation step were carried out in the same manner as in Example 1-4. As a result, 2.7 g of a polythiol composition was obtained (yield: 36% by mass). The content of water (54.0) in the reaction system (15.0 + 72.1 + 10.7 + 32.9) was 35.6% by mass (54.0 / (15.0 + 72.1 + 10.7 + 54.0) × 100).

[0175] [Examples 4-5] <Decomposition of thiourethane resin with diazabicycloundecene (DBU) and isopropanol> The reaction step and separation step were carried out in the same manner as in Example 1-5, except that isopropanol (2-propanol) (72.1 g; 1.2 mol) was used instead of ethanol (55.3 g; 1.2 mol) in the reaction step in Example 1-5, and the reaction temperature was 100°C. As a result, 1.4 g of a polythiol composition was obtained (yield: 19% by mass). The content of water (18.0) in the reaction system (15.0 + 72.1 + 18.3 + 18.0) was 14.6% by mass (18.0 / (15.0 + 72.1 + 18.3 + 18.0) × 100).

[0176] [Example 5-1] <Decomposition of thiourethane resin with tetramethylammonium hydroxide and benzyl alcohol> In Example 1-1, instead of using ethanol (55.3 g; 1.2 mol), benzyl alcohol (129.8 g; 1.2 mol) was used in the reaction step, and the reaction time was changed to 2.75 hours. The reaction step and separation step were carried out in the same manner as in Example 1-1. As a result, 3.0 g (yield: 40% by mass) of a polythiol composition was obtained. The content of water (43.8 × 0.75) in the reaction system (15.0 + 129.8 + 43.8) was 17.4% by mass (43.8 × 0.75 / (15.0 + 129.8 + 43.8) × 100).

[0177] [Example 5-2] <Decomposition of thiourethane resin with benzylamine (primary amine) and benzyl alcohol> In Example 1-2, instead of using ethanol (55.3 g; 1.2 mol), benzyl alcohol (129.8 g; 1.2 mol) was used in the reaction step, and the reaction temperature was 100 ° C., except that the reaction step and separation step were carried out in the same manner as in Example 1-2. As a result, 3.1 g (yield: 41% by mass) of a polythiol composition was obtained. The content of water (18.0) in the reaction system (15.0 + 129.8 + 12.9 + 18.0) was 10.2% by mass (18.0 / (15.0 + 129.8 + 12.9 + 18.0) × 100).

[0178] [Example 5-3] <Decomposition of thiourethane resin with methylethanolamine (secondary amine) and benzyl alcohol> In Example 1-3, instead of using ethanol (55.3 g; 1.2 mol) in the reaction step, benzyl alcohol (129.8 g; 1.2 mol) was used, the reaction time was 3.00 hours, and the reaction temperature was 100 ° C., except that the reaction step and separation step were carried out in the same manner as in Example 1-3. As a result, 2.7 g (yield: 36% by mass) of a polythiol composition was obtained. The content of water (18.0) in the reaction system (15.0 + 129.8 + 12.9 + 32.9) was 10.5% by mass (18.0 / (15.0 + 129.8 + 9.0 + 18.0) × 100).

[0179] [Example 5-4] <Decomposition of thiourethane resin with N,N-dimethylethanolamine (tertiary amine) and benzyl alcohol> In Example 1-4, instead of using ethanol (55.3 g; 1.2 mol) in the reaction step, benzyl alcohol (129.8 g; 1.2 mol) was used, the reaction time was 3.25 hours, and the reaction temperature was 100 ° C., except that the reaction step and separation step were carried out in the same manner as in Example 1-4. As a result, 2.3 g (yield: 30% by mass) of a polythiol composition was obtained. The content of water (18.0) in the reaction system (15.0 + 129.8 + 10.7 + 18.0) was 10.4% by mass (18.0 / (15.0 + 129.8 + 10.7 + 18.0) × 100).

[0180] Example 5-5 Decomposition of thiourethane resin with diazabicycloundecene (DBU) and benzyl alcohol In Example 5-5, instead of using ethanol (55.3 g; 1.2 mol), benzyl alcohol (129.8 g; 1.2 mol) was used in the reaction step, the reaction time was 3.50 hours, and the reaction temperature was 100°C. Except for this, the reaction step and separation step were carried out in the same manner as in Example 5-5. As a result, 1.8 g (yield: 24% by mass) of a polythiol composition was obtained. The content of water (18.0) in the reaction system (15.0 + 129.8 + 18.3 + 18.0) was 9.9% by mass (18.0 / (15.0 + 129.8 + 18.3 + 18.0) × 100).

[0181] [Comparative Example 1] <Decomposition of thiourethane resin by monoethanolamine> (reaction step) 10.2g of the thiourethane resin powder obtained in Production Example 1 was weighed, and the entire amount was placed in a 300mL flask equipped with a condenser. Here, monoethanolamine (5.0g; 0.081mol) as an amine compound and alcohol and toluene (120.0g) as a reaction solvent were added, and the mixture was heated and stirred at 100 ° C. (reaction temperature) for 6.00 hours (reaction time), thereby obtaining a reaction mixture containing a polythiol composition (reaction step). The water content in the reaction system was 0.0% by mass.

[0182] (Separation Step) The reaction mixture obtained in the above reaction step was cooled to room temperature, and then solids were removed by filtration. The obtained filtrate was washed twice with 50 mL of 1 M hydrochloric acid to remove excess monoethanolamine, and then washed twice with 50 mL of water to remove excess hydrochloric acid. From the obtained toluene solution, highly polar by-products were removed using a silica gel column, and then the toluene was distilled off using a rotary evaporator. The obtained mixture was subjected to removal of low-boiling point components using a vacuum pump and filtration through a 1-micron PTFE membrane filter in this order, thereby obtaining 2.8 g (yield: 54 mass%) of a polythiol composition mainly composed of 4,8-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 4,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, and 5,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane (i.e., polythiol components) (these are the separation steps).

[0183] [Comparative Example 2-1] <Decomposition of thiourethane resin with tetramethylammonium hydroxide and methanol> In Example 3-1, instead of using methanol (38.4 g; 1.2 mol) and a 25 mass% tetramethylammonium hydroxide (TMAH) aqueous solution (43.8 g; 0.12 mol) in the reaction step, a 10 mass% tetramethylammonium hydroxide (TMAH) methanol solution (109.4 g; 0.12 mol) was used, the reaction time was 6.00 hours, and the reaction temperature was 60 ° C. The reaction step and separation step were carried out in the same manner as in Example 3-1. As a result, 2.9 g (yield: 38 mass%) of a polythiol composition was obtained. The water content in the reaction system was 0.0 mass%.

[0184] [Comparative Example 2-2] <Decomposition of thiourethane resin with benzylamine (primary amine) and methanol> In Example 3-2, the reaction time in the reaction step was 5.75 hours, and the reaction step and separation step were carried out in the same manner as in Example 3-2, except that 18.0 g of pure water was not used. As a result, 2.5 g of a polythiol composition was obtained (yield: 33% by mass). The water content in the reaction system was 0.0% by mass.

[0185] [Comparative Example 2-3] <Decomposition of thiourethane resin with methylethanolamine (secondary amine) and methanol> In Example 3-3, the reaction time in the reaction step was 6.50 hours, and the reaction step and separation step were carried out in the same manner as in Example 3-3, except that 18.0 g of pure water was not used. As a result, 2.1 g (yield: 28% by mass) of a polythiol composition was obtained. The water content in the reaction system was 0.0% by mass.

[0186] [Comparative Example 2-4] <Decomposition of thiourethane resin with N,N-dimethylethanolamine (tertiary amine) and methanol> The reaction step and separation step were carried out in the same manner as in Example 3-4, except that the reaction time in the reaction step was 6.25 hours and 32.9 g of pure water was not used. As a result, 1.8 g (yield: 24% by mass) of a polythiol composition was obtained. The water content in the reaction system was 0.0% by mass.

[0187] [Comparative Example 2-5] <Decomposition of thiourethane resin with diazabicycloundecene (DBU) and methanol> The reaction step and separation step were carried out in the same manner as in Example 3-5, except that the reaction time in the reaction step was 6.50 hours and 32.9 g of pure water was not used. As a result, 1.1 g (yield: 15% by mass) of a polythiol composition was obtained. The water content in the reaction system was 0.0% by mass.

[0188] [Evaluation of Yield] The yields of Examples 1-1 to 5-5 and Comparative Examples 1 to 2-5 are shown in Table 1.

[0189] [Definition of Reaction Time] The progress of each reaction was monitored every 15 minutes from the start of the reaction by silica gel TLC (thin-layer chromatography). The time until the reaction reached saturation was visually confirmed and recorded as the reaction saturation time. The reaction saturation time was defined as the reaction time. The results are shown in Table 1. The "reaction saturation time" here refers to the time when a small amount of a sample was taken, post-treated to convert thiolate to thiol, and a spot with an Rf value of approximately 0.7 was visually confirmed on TLC (developing solvent: ethyl acetate: toluene = 1:10 to 1:7, detection reagent: phosphomolybdic acid ethanol solution) and no further progress was observed. This is defined as the reaction completion time, i.e., the reaction saturation time. Here, the Rf value is calculated by dividing the distance traveled by the compound by the distance traveled by the solvent on the TLC plate. The phosphomolybdic acid ethanol reagent was prepared by dissolving 5 g of sodium phosphomolybdate n-hydrate in 100 mL of ethanol.

[0190]

[0191] As described above, Table 1 shows that the polythiol composition production methods of Examples 1-1 to 5-5, which include a reaction step of reacting a thiourethane resin and a nitrogen-containing compound in the presence of water to produce a polythiol composition, can produce a polythiol composition in a short reaction time using a thiourethane resin as a starting material.

[0192] The embodiments disclosed herein should be considered illustrative in all respects and not restrictive. The scope of the present disclosure is defined by the claims, not the above description, and is intended to include all modifications within the meaning and scope of the claims. The examples, contents, and various physical properties of the above components of the present disclosure may be arbitrarily combined with the items described as examples or preferred ranges in the detailed description of the invention. Furthermore, by adjusting the compositions described in the examples to achieve the compositions described in the detailed description of the invention, the disclosed embodiments can be practiced in the same manner as the examples throughout the entire range of the claimed compositions.

Claims

1. A method for producing a polythiol composition includes a reaction step of reacting a thiourethane resin with at least one nitrogen-containing compound selected from the group consisting of a quaternary ammonium salt and an amine compound in the presence of water to produce a polythiol composition.

2. The method for producing a polythiol composition according to claim 1, wherein the water content in the reaction system in the reaction step is 2 to 50 mass%.

3. The method for producing a polythiol composition according to claim 1 or 2, wherein the quaternary ammonium salt comprises a quaternary ammonium cation and a counter anion, and the counter anion is a hydroxide ion.

4. The method for producing a polythiol composition according to claim 1 or 2, wherein the amine compound is at least one selected from the group consisting of primary amines, secondary amines, and tertiary amines.

5. The method for producing a polythiol composition according to claim 1 or 2, wherein the reaction system in the reaction step further contains an alcohol.

6. The method for producing a polythiol composition according to claim 5 , wherein the alcohol includes one or more alcohols miscible with water.

7. 3. A method for producing a polymerizable composition, comprising: a step of producing a polythiol composition by the method for producing a polythiol composition according to claim 1 or 2; and a step of mixing the produced polythiol composition with a polyisocyanate compound to obtain a polymerizable composition containing the polythiol composition and a polyisocyanate compound.

8. A method for producing a resin, comprising: producing a polymerizable composition by the method for producing a polymerizable composition according to claim 7; and curing the polymerizable composition to obtain a resin.