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

Abstract

This method for producing a polythiol composition includes a reaction process for generating a polythiol composition by reacting a thiourethane resin with a quaternary ammonium salt comprising a quaternary ammonium cation and a counter anion.

Description

[Technical Field]

[0001] This disclosure relates to a method for producing a polythiol composition, a method for producing a polymerizable composition, and a method for producing a resin. [Background technology]

[0002] Plastic lenses, which contain resin, are lighter, less prone to breakage, and can be dyed compared to inorganic lenses, and have therefore become rapidly popular in recent years for applications such as eyeglass lenses and camera lenses. For example, various studies have been conducted on lenses containing thiourethane resin (see, for example, Patent Documents 1 to 3).

[0003] For the production of thiourethane resin, raw materials (hereinafter also referred to as "thiourethane resin raw materials") include, 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). 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 resin).

[0004] Lenses containing thiourethane resin (e.g., eyeglass lenses) are manufactured by machining molded bodies containing thiourethane resin. As a result, the lens manufacturing process can generate large amounts of waste, such as machining dust containing thiourethane resin. Furthermore, the manufacturing process of molded bodies containing thiourethane resin can result in defective molded or machined products. Such waste has typically been incinerated or landfilled without being effectively utilized (i.e., recycled). Therefore, from the viewpoint of effective utilization of materials, a technology has been developed to produce polythiol compositions using cutting powder containing thiourethane resin, as well as molded and processed defective products, as starting materials (see, for example, Patent Document 4). Here, Patent Document 4 discloses that a polythiol composition can be obtained by a reaction using an amine compound as a base and an organic solvent that is poorly miscible with water (high-boiling point alcohol, toluene). [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 63-46213 [Patent Document 2] Japanese Patent Application Publication No. 2-270859 [Patent Document 3] Japanese Patent Application Publication No. 7-252207 [Patent Document 4] International Publication No. 2021 / 157701 [Overview of the project] [Problems that the invention aims to solve]

[0006] However, the reactions used to produce polythiol compositions are typically carried out in high-temperature ranges, and it had not been possible to carry them out in low-temperature ranges. Therefore, from the viewpoint of reducing energy consumption and suppressing by-product formation, there was a strong desire to develop a reaction system that could produce polythiol compositions using thiourethane resin as a starting material even in low-temperature ranges.

[0007] Under these circumstances, one aspect of the present disclosure aims to provide a method for producing a polythiol composition using a thiourethane resin as a starting material in a wide temperature range (15 to 110°C) including a low temperature range, a method for producing a polymerizable composition using the method for producing the polythiol composition, and a method for producing a resin using the method for producing the polymerizable composition. [Means for solving the problem]

[0008] Embodiments of this disclosure relate to the following [1] to

[10] . [1] A method for producing a polythiol composition, comprising a reaction step of reacting a thiourethane resin with a quaternary ammonium salt composed of a quaternary ammonium cation and a counter anion to produce a polythiol composition. [2] The method for producing a polythiol composition according to [1] above, wherein the counter anion is a hydroxide ion. [3] The method for producing a polythiol composition according to [1] or [2] above, wherein the reaction system in the reaction step further contains an alcohol. [4] The method for producing a polythiol composition according to [3] above, wherein the alcohol contains one or more alcohols miscible with water. [5] The quaternary ammonium cation is NR4 + represented by, and all four Rs are the same group, the method for producing a polythiol composition according to [1] or [2] above. [6] The quaternary ammonium cation is NR4 + represented by, three of the four Rs are the same group, and the other one of the four Rs is a group different from the same group, the method for producing a polythiol composition according to [1] or [2] above. [7] The quaternary ammonium cation is NR4 + represented by, and each of the four Rs is independently a group selected from the group consisting of an alkyl group, an aromatic group, a heteroaryl group, and an ether-containing group, the method for producing a polythiol composition according to [1] or [2] above. [8] The alkyl group has 1 to 20 carbon atoms and is linear, branched, or cyclic, the method for producing a polythiol composition according to [7] above. [9] A step of producing a polythiol composition by the method for producing a polythiol composition according to any one of [1] to [8] above, and a step of obtaining a polymerizable composition containing the polythiol composition and a polyisocyanate compound by mixing the produced polythiol composition with a polyisocyanate compound, a method for producing a polymerizable composition.

[10] A step of producing a polymerizable composition by the method for producing a polymerizable composition described in [9] above, and a step of obtaining a resin by curing the polymerizable composition. A method for producing a resin, which includes these steps.

Advantages of the Invention

[0009] According to one aspect of the present disclosure, a method for producing a polythiol composition capable of producing a polythiol composition using a thiourethane resin as a starting material in a wide temperature range (15 to 110 °C) including a low temperature region, a method for producing a polymerizable composition using the method for producing the polythiol composition, and a method for producing a resin using the method for producing the polymerizable composition can be provided.

Embodiments for Carrying Out the Invention

[0010] Hereinafter, an example of an embodiment of the present disclosure will be described. However, the embodiments shown below are examples for embodying the technical idea of the present disclosure, and the present disclosure is not limited to the following description. Aspects arbitrarily selected from the matters described in this specification or aspects arbitrarily combined are also included in the present disclosure. In this specification, the provisions defined as preferable can be arbitrarily selected, and combinations of the provisions defined as preferable can be said to be more preferable. In this specification, the description "XX to YY" means "XX or more and YY or less". In this specification, for preferable numerical ranges (for example, ranges such as content), the lower limit value and the upper limit value described stepwise can be combined independently of each other. For example, from the description "preferably 10 to 90, more preferably 30 to 60", it is also possible to combine the "preferred lower limit value (10)" and the "more preferred upper limit value (60)" to obtain "10 to 60". In this specification, the amount of each component contained in the composition means the total amount of the plurality of substances present in the composition when there are a plurality of substances corresponding to each component in the composition, unless otherwise specified. In this specification, the term "step" includes not only an independent step but also a step in which, even if it cannot be clearly distinguished from other steps, the intended purpose of the step is achieved. In this specification, the term "reaction system" means "the reaction system in the reaction step in the method for producing a polythiol composition". Note that the reaction system in the reaction step includes optional components such as alcohol, water, and reaction solvents in addition to the essential components consisting of a thiourethane resin and a quaternary ammonium salt. Therefore, the content (% by mass) in the reaction system means the content (% by mass) when the total content of the essential components and the optional components is 100% by mass. In this specification, in the case of a reaction system containing a compound that corresponds to both an alcohol and an amine compound such as monoethanolamine, only one of the alcohol and the amine compound is counted without double-counting both, and the "total content of the essential components and the optional components in the reaction system" is calculated. Here, the "content (% by mass) of alcohol in the reaction system" is a value obtained by dividing the "mass of the compound corresponding to both alcohol and amine compound" by the "total content of the essential components and the optional components in the reaction system" calculated by counting only one of the alcohol and the amine compound. In this specification, when the reaction system (composition) "contains a certain component (hereinafter referred to as 'component X') as a main component", it 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% by mass or more based on the total amount of the reaction system (composition). The content of component X, which is the main component, 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, "high boiling point" in "high boiling point alcohol" means 140 °C or higher. In this specification, R 3 、R 4 、R 5 、R 6 、R 11 、R 12The definition and examples of R shall be the same as those of R in quaternary ammonium compounds.

[0011] [Method for producing polythiol composition] A method for producing a polythiol composition according to the embodiments of this disclosure includes a reaction step of reacting a thiourethane resin with a quaternary ammonium salt comprising a quaternary ammonium cation and a counteranion to produce a polythiol composition. The method for producing the polythiol composition according to the embodiment of this disclosure involves reacting a thiourethane resin with a quaternary ammonium salt consisting of a quaternary ammonium cation and a counteranion. Therefore, the polythiol composition can be produced using the thiourethane resin as a starting material in a wide temperature range (15 to 110°C), including the low temperature range. If the reaction system further contains alcohol, alcoholic decomposition occurs in the above reaction step, in which the thiourethane resin is decomposed by the alcohol, and this alcoholic decomposition produces the target product, the polythiol composition. If the reaction system further contains alcohol, in the above reaction step, the alcohol is thought to function as a decomposition agent in the alcohol decomposition, and the quaternary ammonium salt is thought to function as a decomposition aid in the alcohol decomposition. Specifically, the right-hand side of the reaction equation (1) below contains "R 3 O - It is presumed that this promotes the decomposition of the thiourethane resin. Here, the left side of the reaction equation (1) below is "quaternary ammonium salt (quaternary ammonium cation NR4 + +Counter Anion X - ) and "Alcohol R 3 It represents "OH". If the reaction system does not contain alcohol, it is thought that the counteranion in the quaternary ammonium salt, which is a nitrogen-containing compound, undergoes a nucleophilic reaction with the carbon of the carbonyl group of the thiourethane resin (see reaction equation (X) below).

[0012] [ka]

[0013] [ka]

[0014] A method for producing a polythiol composition according to the embodiments of this 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 (grinding) step. The following describes each step that may be included in the method for producing a polythiol composition.

[0015] [[Reaction Process]] The reaction process involves reacting a thiourethane resin with a quaternary ammonium salt and, if necessary, an optional component such as an alcohol to produce a polythiol composition.

[0016] <Thiourethane resin> Thiourethane resin is the starting material in this process and in the method for producing the polythiol composition. There are no particular restrictions on the thiourethane resin, and examples include thiourethane resins described in publicly available documents such as Japanese Patent Publication No. 63-46213, Japanese Patent Publication No. 2-270859, Japanese Patent Publication No. 7-252207, and International Publication No. 2008 / 047626.

[0017] 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 MR-6, MR-7, MR-8, MR-8Plus, MR-60, MR-10, and MR-20 (all manufactured by Mitsui Chemicals, Inc.); and EYAS1.60 (manufactured by HOYA Corporation).

[0018] Preferably, the thiourethane resin is recovered during at least one of the following processes: the manufacturing process of eyeglass lenses, the manufacturing process of eyeglasses, and the disposal process of eyeglasses. According to this embodiment, recycling of the thiourethane resin, which is a material for eyeglass lenses, is achieved. Here, the manufacturing process of eyeglass lenses refers to the process of producing resin by mixing monomers, which are the raw materials for resin, and casting polymerization, and / or the process of obtaining eyeglass lenses by cutting and shaping the resin molded body; the manufacturing process of eyeglasses refers to the process of producing eyeglasses by combining eyeglass lenses with other components such as eyeglass frames; and the disposal process of eyeglasses refers to the process of disposing of eyeglasses that have been manufactured but are no longer needed, used eyeglasses, etc. In either process, thiourethane resin, the material used for eyeglass lenses, may be generated as waste. It is preferable to use the thiourethane resin produced in at least one of these processes as a starting material, and to react this thiourethane resin with a quaternary ammonium salt and, if necessary, an optional component such as an alcohol, to obtain a polythiol composition, which is a decomposition product of the thiourethane resin.

[0019] As described above, the method for producing the polythiol composition of this disclosure makes it possible to reduce the amount of thiourethane resin that is incinerated by using used thiourethane resin for the production of the polythiol composition, and as a result it is possible to reduce the generation of greenhouse gases such as carbon dioxide, sulfur oxides, nitrogen oxides, and other air pollutants. Furthermore, since thiourea is not used in the production of the polythiol composition, there is no generation of wastewater containing thiourea, making it an environmentally friendly production method. To illustrate with a specific example, when 1 kg of thiourethane resin is incinerated, the carbon, nitrogen, and sulfur content in the resin is 48.5% by mass, 7.6% by mass, and 30.2% by mass, respectively. When this thiourethane resin is burned, various types of oxides of carbon, nitrogen, and sulfur atoms are produced 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 will be produced. The method for producing the polythiol composition described herein makes it possible to reduce the generation of carbon dioxide, nitric oxide, and sulfur dioxide.

[0020] The above starting materials preferably include cutting powder containing thiourethane resin. In the step of producing the polythiol composition in this embodiment, the thiourethane resin is reacted with the quaternary ammonium salt and the optional component such as alcohol by contacting the cutting powder containing the thiourethane resin with the quaternary ammonium salt and, if necessary, with an optional component such as alcohol. In this embodiment, the reactivity between the thiourethane resin in the starting material, the quaternary ammonium salt, and any optional component such as the alcohol is superior, making it possible to produce the polythiol composition more effectively.

[0021] (Powder containing thiourethane resin) In the reaction step, it is preferable to react the thiourethane resin in the powder with the quaternary ammonium salt and the optional component such as alcohol by bringing the powder containing the thiourethane resin (hereinafter also referred to as "thiourethane resin powder") into contact with the quaternary ammonium salt and the optional component such as alcohol. This makes it possible to further improve the reaction efficiency between the thiourethane resin, the quaternary ammonium salt and the optional component such as alcohol. There are no particular restrictions on the method of contacting the thiourethane resin powder, the quaternary ammonium salt, and any other component such as alcohol. For example, one method is to place the thiourethane resin powder and the quaternary ammonium salt (and, if necessary, alcohol, reaction solvent, etc.) into a reaction vessel and stir. In this example, there are no particular restrictions on the order in which the thiourethane resin powder and the quaternary ammonium salt (and, if necessary, alcohol, reaction solvent, etc.) are placed into the reaction vessel.

[0022] The thiourethane resin powder is not particularly limited, but is preferably cutting powder (including the concept of abrasive powder; the same applies hereinafter) from a molded article containing thiourethane resin and / or the cutting powder that has been sieved (i.e., cutting powder that has passed through the sieve). Cutting powder from molded bodies containing thiourethane resin is generated, for example, when manufacturing optical materials (e.g., lenses) by cutting molded bodies containing thiourethane resin. Furthermore, the thiourethane resin powder may also be a lump powder obtained by crushing and / or grinding a molded body containing thiourethane resin.

[0023] There are no particular restrictions on the content of thiourethane resin in the reaction system of the reaction step, but from the viewpoint of further improving the reactivity of the thiourethane resin, it is preferably 2 to 50% by mass, more preferably 4 to 30% by mass, and particularly preferably 6 to 20% by mass.

[0024] (Polyisocyanate compounds as raw materials for thiourethane resins) The polyisocyanate compound used as a raw material for thiourethane resin may be one type or two or more types. The polyisocyanate compound used as a raw material for thiourethane resin preferably contains a polyisocyanate compound that has two or more isocyanate groups. Examples of polyisocyanate compounds used as raw materials for thiourethane resins include the known polyisocyanate compounds described in the aforementioned prior art publications (i.e., Japanese Patent Publication No. 63-46213, Japanese Patent Publication No. 2-270859, Japanese Patent Publication No. 7-252207, International Publication No. 2008 / 047626, etc.).

[0025] (Polythiol composition as a raw material for thiourethane resin) The polythiol composition used as a raw material for thiourethane resin may consist of only one polythiol compound or two or more polythiol compounds. The polythiol composition used as a raw material for thiourethane resin only needs to contain a polythiol compound containing two or more thiol groups (i.e., mercapto groups), and is not particularly limited in any other respect. Examples of polythiol compositions used as raw materials for thiourethane resins include the known polythiol compositions described in the aforementioned prior art publications (i.e., Japanese Patent Publication No. 63-46213, Japanese Patent Publication No. 2-270859, Japanese Patent Publication No. 7-252207, International Publication No. 2008 / 047626, etc.).

[0026] The thiourethane resin may contain other components besides a polymer of at least one polyisocyanate compound and a polythiol composition. For other components that may be contained in the thiourethane resin, refer to the components that may be contained in the polymerizable composition described later as appropriate.

[0027] <Quaternary ammonium salts> The quaternary ammonium salt is not particularly limited as long as it consists of a quaternary ammonium cation and a counteranion, and 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.

[0028] If the reaction system contains an alcohol as an optional component, as shown in the reaction equation (1) below, the left side of the equation is "quaternary ammonium salt (quaternary ammonium cation NR4 + and Counter Anion X - ) and "Alcohol R 3 The "OH" reacts, and the "NR4" on the right side + "R 3 O - " is generated. As shown in the reaction equation (2) below, the generated "R 3 O - It is presumed that this is promoting the decomposition of the thiourethane resin. Furthermore, if the reaction system does not contain alcohol as an optional component, the resulting "X" will be as shown in the reaction equation (X) below. - It is presumed that this is promoting the decomposition of the thiourethane resin.

[0029] [ka]

[0030] [ka]

[0031] [ka]

[0032] There are no particular restrictions on the content of the quaternary ammonium salt in the reaction system of the reaction step, but from the viewpoint of further improving the reactivity with the thiourethane resin, it is preferably 1 to 40% by mass, more preferably 2 to 30% by mass, and particularly preferably 3 to 20% by mass.

[0033] (Amount of quaternary ammonium salt to be prepared) In the reaction process, the charging mass ratio of the quaternary ammonium salt to the thiourethane resin (i.e., charging 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 mass ratio of the preparation [quaternary ammonium salt / thiourethane resin] is 0.1 or higher, the formation of the polythiol composition is further promoted. When the mass ratio of the charge [quaternary ammonium salt / thiourethane resin] is 10 or less, the residual amount of quaternary ammonium salt in the reaction mixture can be further suppressed.

[0034] In the reaction process, the number of millimoles of quaternary ammonium salt added per 1 g of 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.

[0035] In the reaction process, the equivalent amount of quaternary ammonium salt added to the thiourethane resin (equivalent amount [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 equivalent amount of the preparation [quaternary ammonium salt / thiourethane resin] is 1.0 or more, the formation of the polythiol composition is further promoted. When the equivalent charge [quaternary ammonium salt / thiourethane resin] is 6.0 or less, the residual amount of quaternary ammonium salt in the reaction mixture can be further suppressed. Here, the equivalent amount of quaternary ammonium salt added to the thiourethane resin (equivalent amount [quaternary ammonium salt / thiourethane resin]) refers to the ratio of the number of quaternary ammonium cations in the added quaternary ammonium salt to the total number of thiourethane bonds in the added thiourethane resin.

[0036] (Quaternary ammonium cation) Quaternary ammonium cation is NR4 + This is represented as follows, but all four Rs may be the same group, three of the four Rs may be the same group, and the remaining one of the four Rs may be a different group from the aforementioned same group.

[0037] Quaternary ammonium cation (NR4 + Specific examples of these include, for instance, the tetramethylammonium ion (all four R groups are methyl groups), the tetraethylammonium ion (all four R groups are ethyl groups), the tetrabutylammonium ion (all four R groups are butyl groups), and the benzyltrimethylammonium ion (of which three R groups are methyl groups and the other one is a benzyl group).

[0038] Quaternary ammonium cation NR4 + The four R groups in this combination are not particularly limited; for example, each can be independently selected from the group consisting of alkyl groups, aromatic groups, heteroaryl groups, and ether-containing groups.

[0039] There are no particular restrictions on the alkyl group, but it is preferable that it has 1 to 20 carbon atoms and is linear, branched, or cyclic. Here, the alkyl group may be a substituted alkyl group with substituents, or an unsubstituted alkyl group without substituents. Examples of substituents include nitro groups and hydroxyl groups. Note that the carbon number of the alkyl group refers to the carbon number when the alkyl group is unsubstituted, and does not include the carbon number of substituents when it is substituted. Specific examples of unsubstituted alkyl groups that do not have substituents include, for example, methyl, ethyl, propyl, butyl, pentyl, hexyl, and heptyl groups.

[0040] There are no particular restrictions on the aromatic group, but it is preferable that it has 4 to 20 carbon atoms. Here, the aromatic group may be a substituted aromatic group with substituents, or an unsubstituted aromatic group without substituents. Examples of substituents include methyl groups, nitro groups, and hydroxyl groups. Note that the number of carbon atoms of the aromatic group refers to the number of carbon atoms when the aromatic group is unsubstituted, and does not include the number of carbon atoms of substituents when it is substituted. Specific examples of unsubstituted aromatic groups that do not have substituents include, for example, benzyl, phenyl, naphthyl, phenethyl, anthryl, pyrenyl, and thiophenyl groups.

[0041] There are no particular restrictions on the heteroaryl group, but it is preferable that it has 4 to 20 carbon atoms. Here, the heteroaryl group may be a substituted heteroaryl group with substituents, or an unsubstituted heteroaryl group without substituents. Examples of substituents include a methyl group, a nitro group, a hydroxyl group, and so on. Note that the carbon number of the heteroaryl group represents the carbon number when the heteroaryl group is unsubstituted, and does not include the carbon number of substituents when it is substituted. Specific examples of unsubstituted heteroaryl groups without substituents include, for example, a monocyclic or ring-assembled group from pyrrol, imidazole, pyrazole, triazole, furan, thiophene, thiazole, isothiazole, oxazole, isooxazole, oxadiazole, thiadiazole, pyridine, pyrazine, pyridazine, pyrimidine, triazine, bipyrrole, terpyrrole, bithiophene, terthiophene, bipyridine, and terpyridine, with one hydrogen atom removed from the carbon or nitrogen atom of the group. Examples include a non-condensed heteroaryl group, which is a monovalent residue obtained from the following: a condensed heteroaryl group, which is a monovalent residue obtained by removing one hydrogen atom from the carbon or nitrogen atom of a compound selected from indole, carbazole, imidazole, benzimidazole, di(benzoimidazo)benzo[1,3,5]triazepine, (benzoimidazo)benzimidazole, (benzoimidazo)phenanthidine, (benzoindo)benzoazepine, dibenzofuran, and dibenzothiophene.

[0042] There are no particular restrictions on the ether-containing group, but it is preferable that it has 2 to 20 carbon atoms. Here, the ether-containing group may be a substituted ether-containing group with substituents, or an unsubstituted ether-containing group without substituents. Examples of substituents include a methyl group, a nitro group, a hydroxyl group, and so on. Note that the carbon number of the ether-containing group represents the carbon number when the ether-containing group is unsubstituted, and does not include the carbon number of substituents when it is substituted. Specific examples of unsubstituted ether-containing groups without substituents include, for example, polyoxyalkylene groups, polyglycerin groups, tetrahydrofuranyl groups, and benzofuranyl groups.

[0043] (Counter-anion (counter-ion)) Counter Anion X ― There are no particular restrictions, but halogen ions such as fluoride ions, chloride ions, bromide ions, and iodide ions; OR ions such as hydroxide ions. 2-Anions represented by ; and others. These may be used individually or in combination of two or more. Note that R 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-off ability.

[0044] <Optional ingredients> There are no particular restrictions on optional components, and examples include alcohols, water, reaction solvents, amine compounds, and bases other than quaternary ammonium salts such as sodium hydroxide.

[0045] (alcohol) In the reaction step, it is preferable to react the thiourethane resin with at least one alcohol as an optional component. The optional component, alcohol, is thought to function as a decomposing agent for thiourethane resin. Any known alcohol can be used as the optional alcohol component in the reaction system of the reaction step without any particular restrictions. The alcohol (i.e., the alcohol that may be reacted with the thiourethane resin), which is an optional component in the reaction system of the reaction step, may be one type or two or more types. The alcohol, which is an optional component in the reaction system of the reaction step, may be a monoalcohol containing only one hydroxyl group, or a polyol containing two or more hydroxyl groups. The alcohol, which is an optional component in the reaction system of the reaction step, may be any of the following: primary alcohols such as ethanol, n-propanol, or monoethanolamine; secondary alcohols such as isopropanol (2-propanol); or tertiary alcohols such as t-butyl alcohol. However, from the viewpoint of reaction in a low-temperature range, lower alcohols such as methanol or ethanol are preferred.

[0046] There are no particular restrictions on specific examples of alcohols, which are optional components in the reaction system of the reaction step. Examples include 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, monoethanolamine, and the like. These may be used individually or in combination of two or more. Among these, it is preferable to include one or more alcohols that are miscible with water, from the viewpoint of miscibility with quaternary ammonium salt aqueous solutions. Examples of alcohols that are miscible with water 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 "10 g or more of the alcohol compound dissolves in 1 kg of water at room temperature (25°C) and atmospheric pressure (1 atm)."

[0047] From the viewpoint of further improving reactivity with thiourethane resin, the molecular weight of the alcohol, which is an optional component in the reaction system of the reaction step, is preferably 1000 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 an alcohol, which is an optional component in the reaction system of the reaction step, is, for example, 30 or more. There are no particular restrictions on the molecular weight of the alcohol, which is an optional component in the reaction process, but it is preferably 30 to 1000, more preferably 30 to 500, even more preferably 30 to 300, and most preferably 30 to 200.

[0048] The alcohol, which is an optional component in the reaction system of the reaction step, preferably contains an alcohol with a boiling point of 60°C to 250°C (hereinafter also referred to as "alcohol A"). In this specification, boiling point means the boiling point at 1 atmosphere (101325 Pa).

[0049] The proportion of alcohol A in the total amount of alcohol, which is an optional component in the reaction system of the reaction step, is preferably 50% to 100% by mass, more preferably 60% to 100% by mass, and particularly preferably 80% to 100% by mass.

[0050] There are no particular restrictions on the content of alcohol, which is an optional component in the reaction system of the reaction step. However, from the viewpoint of further improving the reactivity with the thiourethane resin, it is preferably 20 to 90% by mass, more preferably 30 to 80% by mass, and particularly preferably 35 to 70% by mass.

[0051] The following shows the preferred amount of alcohol, an optional component in the reaction system of the reaction process. The preferred fermentation amounts shown below also correspond to the preferred fermentation amounts for alcohol A (i.e., alcohol with a boiling point of 60°C to 250°C).

[0052] ((Amount of alcohol, an optional component in the reaction system of the reaction process)) In the reaction process, the charge mass ratio of alcohol, an optional component, to the thiourethane resin (i.e., 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 mass ratio of the preparation [alcohol / thiourethane resin] is 0.10 or higher, the formation of the polythiol composition is further promoted. When the mass ratio of the initial mixture [alcohol / thiourethane resin] is 20 or less, the residual alcohol in the reaction mixture can be further suppressed.

[0053] In the reaction process, the number of millimoles of alcohol, an optional component, added per 1 g of thiourethane resin is preferably 1.0 to 100.0 mmol / g, more preferably 10.0 to 90.0 mmol / g, and particularly preferably 50.0 to 85.0 mmol / g.

[0054] In the reaction step, the amount of alcohol added to the thiourethane resin (additional amount [alcohol / thiourethane resin]) is preferably 1.0 to 25, more preferably 1.2 to 20, and particularly preferably 1.5 to 15. When the equivalent amount of alcohol / thiourethane resin used is 1.0 or more, the formation of the polythiol composition is further promoted. When the equivalent amount of alcohol / thiourethane resin used is 25 or less, the residual alcohol in the reaction mixture can be further suppressed. Here, the equivalent amount of alcohol added to the thiourethane resin (equivalent amount [alcohol / thiourethane resin]) refers to the ratio of the number of hydroxyl groups in the added alcohol to the total number of thiourethane bonds in the added thiourethane resin.

[0055] (water) There are no particular restrictions on the water content in the reaction system of the reaction step, but from the viewpoint of further improving the reactivity between the thiourethane resin and the alcohol, it is preferably 0 to 50% by mass, more preferably 5 to 50% by mass, even more preferably 10 to 40% by mass, and particularly preferably 15 to 35% by mass.

[0056] (reaction solvent) In the reaction step, the thiourethane resin, the quaternary ammonium salt, and an alcohol as an optional component may be reacted in the presence of a reaction solvent. The reaction solvent refers to a reaction solvent other than alcohol and water as optional components, and examples 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 individually or in combination of two or more.

[0057] The hydrocarbons mentioned above are 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 above ether is preferably diethyl ether, tetrahydrofuran, 2-methyltetrahydrofuran, dimethoxyethane, or 1,4-dioxane, and more preferably dimethoxyethane. The ketones mentioned above are preferably acetone, methyl ethyl ketone, methyl isobutyl ketone, or 2-octanone, and more preferably methyl isobutyl ketone. The esters mentioned above are preferably ethyl acetate, butyl acetate, or pentyl acetate, and more preferably pentyl acetate. The nitrile is preferably acetonitrile or propionitrile, and more preferably acetonitrile.

[0058] There are no particular restrictions on the content of the reaction solvent in the reaction system of the reaction step, but from the viewpoint of further improving the reactivity with the thiourethane resin, it is preferably 50% by mass or less, more preferably 40% by mass or less, and particularly preferably 20% by mass or less.

[0059] <Reaction temperature> The reaction temperature between the thiourethane resin, the quaternary ammonium salt, and the optional alcohol component during the reaction process can be adjusted as appropriate. In the reaction step, it is preferable to react the thiourethane resin, the quaternary ammonium salt, and an alcohol as an optional component under temperature conditions of 15 to 110°C (more preferably 15°C or higher and less than 50°C, and particularly preferably 15 to 40°C) (i.e., the reaction temperature). When the reaction temperature is between 15 and 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 process may be carried out under pressurized conditions. Carrying the reaction under pressurized conditions may shorten the reaction time.

[0060] Note that conventional alcohol (R 3 OH) and tertiary amines (NR 4 R 5 R 6 In reaction systems using ), the reason why the reaction does not proceed in the low-temperature range is that conventional reaction systems using alcohols and tertiary amines have "R" on the right-hand side of the reaction equation (3) below. 3 O - It is presumed that this is because the reaction system requires high temperatures to shift the reaction equilibrium to the right in order to produce "R". On the other hand, in the reaction system of reaction equation (1) described above, even in the low temperature region, the reaction equilibrium shifts to the right and the right-hand side "R" 3 O - It is presumed that this is a reaction system that produces "[ ]". [ka]

[0061] <Reaction time> The reaction time between the thiourethane resin, the quaternary ammonium salt, and the optional alcohol in the reaction step can be adjusted as appropriate, but is preferably 0.1 to 50.0 hours, more preferably 0.5 to 30.0 hours, and particularly preferably 1.0 to 20.0 hours.

[0062] <Polythiol composition> In this disclosure, "polythiol composition" means a composition containing at least one polythiol compound, and may also contain other components such as polyisocyanate compounds and polyamine compounds. In this disclosure, the polythiol compound contained in the polythiol composition is also referred to as the "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 at least one polythiol compound relative to the total amount of the polythiol composition is 50% by mass or more. The total content of 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.

[0063] Examples of polythiol compositions as target products include polythiol compositions containing known polythiol compounds.

[0064] The polythiol composition as the target product and the polythiol composition used as a raw material for the thiourethane resin as a starting material do not need to be completely identical. However, from the viewpoint of the performance of the thiourethane resin produced by 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, it is possible to produce optical material B (an optical material containing thiourethane resin) having performance comparable to optical material A, using cutting powder (thiourethane resin) generated during the production of optical material A as a raw material.

[0065] The target polythiol composition may have the same polythiol component as the starting material used as a raw material for thiourethane resin, and may also have a reduced amount of impurities. When the content of impurities is reduced in the target polythiol composition, the thickening of the polythiol composition is suppressed, which may have the advantage of a longer pot life.

[0066] There are no particular restrictions on the use of the polythiol composition as the target product. The polythiol composition as the target product can be used, for example, in the production of thiourethane resins. Specific applications of the target polythiol composition include polythiol compositions for the manufacture of optical materials (e.g., eyeglass lenses). In other words, a specific example of the method for producing the polythiol composition of this disclosure is a method for producing a polythiol composition for the manufacture of optical materials. In this specific example, if cutting powder containing thiourethane resin generated during the manufacture of optical materials is used as the starting material, the effective utilization (i.e., recycling) of the material (thiourethane resin and its raw material, the polythiol composition) can be effectively realized. Furthermore, in the reaction step described herein, a polythiol composition is obtained by reacting a thiourethane resin with a quaternary ammonium salt, thereby obtaining a polythiol composition with a higher purity of the polythiol component as the main component compared to known methods (for example, a method of obtaining a polythiol composition by reacting a thiourethane resin with sodium hydroxide). Therefore, even when the polythiol composition is used as the target product in the manufacture of optical materials (e.g., lenses), optical materials with good performance can be obtained. The properties of optical materials include optical properties (e.g., refractive index and / or Abbe number), heat resistance, and specific gravity.

[0067] (Polythiol compounds) There are no particular restrictions on polythiol compounds, as long as they contain two or more thiol groups (also known as mercapto groups). For polythiol compounds, you can refer to the aforementioned prior art publications (i.e., Japanese Patent Publication No. 63-46213, Japanese Patent Publication No. 2-270859, Japanese Patent Publication No. 7-252207, International Publication No. 2008 / 047626, etc.) as appropriate.

[0068] There are no particular restrictions on the polythiol compound, but suitable examples 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 individually or in combination of two or more types. The polythiol composition more preferably contains polythiol component A as its main component. In this case, the polythiol composition may also contain at least one other component other than polythiol component A (for example, other polythiol compounds, components other than polythiol compounds, etc.).

[0069] 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, and the like. These may be used individually or in combination of two or more.

[0070] (Polyisocyanate compounds) A polyisocyanate compound is any compound that contains two or more isocyanate groups. There are no particular restrictions on the polyisocyanate compound, and examples 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, phenylene diisocyanate, and the like. These may be used individually 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.

[0071] (Polyamine compounds) A polyamine compound can be any compound containing two or more amino groups. The polyamine compounds are not particularly limited, and examples 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, phenylenediamine, and the like. These may be used individually 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.

[0072] (Preferred embodiment of the process for producing a polythiol composition) The process for producing the polythiol composition preferably involves reacting a thiourethane resin with a quaternary ammonium salt and an alcohol as an optional component to produce a polythiol compound and an optional polyamine compound as the polythiol composition. In this preferred embodiment, a decomposition reaction occurs in which the thiourethane resin is decomposed by alcohol as a decomposition agent into a polythiol compound and an arbitrary polyamine compound. The above decomposition reaction is an alcohol-based decomposition reaction.

[0073] (Resin mixture containing thiourethane resin) The process for producing the polythiol composition may involve contacting a resin mixture containing a thiourethane resin with a quaternary ammonium salt and an alcohol as an optional component, thereby reacting the thiourethane resin in the resin mixture with the quaternary ammonium salt and the alcohol as an optional component to produce the polythiol composition.

[0074] The resin mixture containing thiourethane resin further contains components other than thiourethane resin. Other components besides thiourethane resin include resins other than thiourethane resin, and inorganic materials for lens fabrication (e.g., glass).

[0075] Other than thiourethane resin, there are no particular restrictions, and examples include: a hybrid material of thiourethane resin and urethane resin produced by adding polyol to the raw materials when manufacturing thiourethane resin; a hybrid material of thiourethane resin and urea resin produced by adding a polyamine compound to the raw materials when manufacturing thiourethane resin; a polyolefin film to protect the surface of a resin molded body for eyeglass lens manufacturing; a hard coat or primer coat to protect the surface of a resin molded body for eyeglass lens manufacturing; an abrasive used when polishing a resin molded body for eyeglass lens manufacturing; a resin material for fixing a resin molded body when cutting a resin molded body for eyeglass lens manufacturing; and tape or tape adhesive used to fix a glass mold used when creating a resin molded body for eyeglass lens manufacturing. There are no particular limitations on specific examples of resins other than thiourethane resin, but suitable examples include polycarbonate resin, polyallyl carbonate resin, acrylic resin, urethane resin, and episulfide resin.

[0076] It is preferable that the resin mixture containing thiourethane resin is recovered during at least one of the following processes: the manufacturing process of eyeglass lenses, the manufacturing process of eyeglasses, and the disposal process of eyeglasses. The manufacturing process for eyeglass lenses, the manufacturing process for eyeglasses, and the disposal process for eyeglasses are as described above. The resin mixture containing thiourethane resin preferably contains cutting powder containing thiourethane resin.

[0077] (Reaction mixture containing a polythiol composition) The step of producing the polythiol composition may involve reacting a thiourethane resin with a quaternary ammonium salt and an alcohol as an optional component to produce a polythiol composition, thereby obtaining a reaction mixture containing the target polythiol composition. The reaction mixture may contain a polythiol composition as the main product produced by alcohol decomposition, and other components other than the polythiol composition. Other components in the reaction mixture besides the polythiol composition include by-products produced by alcohol decomposition (e.g., polycarbamates), the aforementioned reaction solvent, residues of the raw materials (thiourethane resin, quaternary ammonium salt, and / or alcohol as an optional component), and impurities contained in the raw materials.

[0078] [[Separation process]] The method for producing the polythiol composition may include a separation step of separating the target polythiol composition from the reaction mixture containing the above-mentioned polythiol composition. There are no particular restrictions on the separation method used in the separation process, and known methods include filtration, decantation, extraction, distillation, drying (including vacuum drying), and purification (e.g., column chromatography). These methods may be used individually or in combination of two or more.

[0079] 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.

[0080] Methods for separating polythiol compounds in a polythiol composition include extraction with an organic solvent or inorganic solvent capable of dissolving the polythiol compounds. Common purification methods for polythiol compounds include column purification, distillation purification, recrystallization purification, and salt extraction.

[0081] Methods for separating polyamine compounds in polythiol compositions include extraction with an organic solvent or inorganic solvent capable of dissolving the polyamine compounds. Common purification methods for polyamine compounds include column purification, distillation purification, recrystallization purification, and salt extraction.

[0082] If the step for producing the polythiol composition is the step for producing the polythiol compound and the polyamine compound as described above, the separation step preferably includes at least one of the following: filtering the reaction mixture containing the polythiol compound and the polyamine compound derivative to obtain a filtrate containing the polythiol compound as the filtrate, and obtaining a mixture containing the polyamine compound derivative as the filtrate.

[0083] If the separation step includes obtaining a filtrate containing a polythiol compound as the filtrate, the polythiol compound as a polythiol composition can be obtained by separating the polythiol compound from the filtrate. An example of the separation process in this case is a method that includes: filtering a reaction mixture containing a polythiol compound and a polyamine compound as a polythiol composition to obtain a filtrate containing the polythiol compound; adding a base containing an alkali metal to the filtrate containing the polythiol compound, followed by adding water to perform extraction, to obtain an aqueous extract containing the 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 extracted with water to obtain an aqueous extract containing the alkali metal salt of the polythiol compound. Next, by adding acid to this extract, the alkali metal salt of the polythiol compound is converted back to the polythiol compound. The polythiol compound is extracted from the obtained aqueous liquid containing the polythiol compound using the above extraction solvent to obtain an extract containing the polythiol compound. The polythiol compound is then separated from the obtained extract containing the polythiol compound. According to this example, even when the filtrate containing the polythiol compound contains a large amount of other components besides the polythiol compound, a polythiol compound with higher purity of the main polythiol component can be obtained.

[0084] There are no particular restrictions on the alkali metal in a base containing an alkali metal, but preferably sodium, potassium, and lithium, and more preferably sodium and potassium. There are no particular restrictions on alkali metal-containing bases, but examples include sodium methoxide, sodium ethoxide, sodium propoxide, sodium hydroxide, potassium hydroxide, and lithium hydroxide. Alkali metal bases can be added to the filtrate in the form of an alcohol solution (methanol solution, ethanol solution, etc.) as needed.

[0085] There are no particular restrictions on the acid added to the aqueous extract containing the alkali metal salt of the polythiol compound, but examples include hydrochloric acid, carbonic acid, nitric acid, sulfuric acid, acetic acid, formic acid, oxalic acid, etc.

[0086] The extraction solvent may be one type or two or more types. The preferred embodiment of the extraction solvent is the same as the preferred embodiment of the reaction solvent described above. However, the reaction solvent and the extraction solvent may be the same or different.

[0087] [[Other processes]] The method for producing the polythiol composition may include other steps besides those described above, if necessary. Other processes include, for example, classification, sieving, washing, and crushing (grinding) processes.

[0088] <Classification process> A method for producing a polythiol composition may further include a classification step, prior to the reaction step for producing the polythiol composition, in which cutting powder containing a thiourethane resin is classified to obtain a powder containing a thiourethane resin with a smaller average particle size (for example, the average number of circle equivalent diameters) than the aforementioned cutting powder (i.e., cutting powder with a reduced average particle size).

[0089] In the reaction step for producing the polythiol composition, which includes this classification step, the thiourethane resin in the powder reacts with the quaternary ammonium salt and the alcohol as an optional component by contacting the powder with the alcohol as an optional component. If the method for producing the polythiol composition includes a classification step, the reaction step involves contacting a powder consisting of particles with a small particle size (i.e., average particle diameter) with the quaternary ammonium salt and the alcohol as an optional component. This makes it possible to further improve the reaction efficiency between the thiourethane resin in the powder, the quaternary ammonium salt, and the alcohol as an optional component.

[0090] Examples of average particle diameters include the number-average particle diameter. Examples of particle size include the equivalent diameter of a circle. Classification methods include sieving and centrifugation. For details on the sieving process used for classification, please refer to the sieving process described below.

[0091] <Sieving process> The method for producing the polythiol composition may include a sieving step before the reaction step for producing the polythiol composition, in which cutting powder containing thiourethane resin is sieved to obtain powder containing thiourethane resin that has passed through the sieve (i.e., cutting powder that has passed through the sieve). In the reaction step for producing the polythiol composition, which includes this sieving step, the thiourethane resin in the powder reacts with the quaternary ammonium salt and the alcohol as an optional component by contacting the powder with the alcohol as an optional component. When the method for producing the polythiol composition includes a sieving step, the reaction step involves contacting a powder consisting of small particles with a quaternary ammonium salt and an optional alcohol, thereby improving the reaction efficiency between the thiourethane resin, the quaternary ammonium salt, and the optional alcohol.

[0092] There are no particular restrictions on the above sieve. The nominal mesh opening of the sieve as defined 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, even more preferably 0.3 to 2 mm, and particularly preferably 0.5 to 1.5 mm.

[0093] <Washing process> The method for producing the polythiol composition may include a washing step in which the thiourethane resin powder (i.e., powder containing thiourethane resin) is washed with a hydrocarbon having 5 to 12 carbon atoms as a washing solvent, prior to the reaction step for producing the polythiol composition. In the reaction step for producing the polythiol composition, which includes this washing step, the powder washed in the washing step is brought into contact with the quaternary ammonium salt and the alcohol as an optional component, thereby reacting the thiourethane resin in the powder with the quaternary ammonium salt and the alcohol as an optional component. This results in a polythiol composition with a higher purity of the polythiol component as the main component. In particular, when using cutting powder containing thiourethane resin as a starting material in the method for producing a polythiol composition, the above-mentioned cleaning step can effectively remove oil from the cutting machine adhering to the cutting powder, thereby obtaining a polythiol composition with a higher purity of the polythiol component as the main component.

[0094] The hydrocarbon used as the washing solvent may be used alone or in combination of two or more types. The preferred embodiment of the hydrocarbon as a washing solvent is the same as the preferred embodiment of the hydrocarbon as a reaction solvent described above. However, the reaction solvent and the washing solvent may be the same or different.

[0095] There are no particular restrictions on the cleaning method in the cleaning process; known methods such as adding the above-mentioned cleaning solvent to the thiourethane resin powder and mixing it can be applied.

[0096] When the method for producing the polythiol composition includes the aforementioned sieving step and washing step, it is preferable to perform the sieving step and washing step in that order. In this case, there is no need to wash the cutting powder that did not pass through the sieve, so the amount of washing solvent used can be further reduced.

[0097] <Crushing (Mashing) Process> The method for producing the polythiol composition may include a crushing (grinding) step of crushing and / or grinding the thiourethane resin before the reaction step that produces the polythiol composition. There are no particular restrictions on the crushing (grinding) method in the crushing (grinding) process, and known methods can be applied.

[0098] [Method for producing polymerizable compositions] The method for producing the polymerizable composition of the present disclosure includes the steps of: producing a polythiol composition by the method for producing a polythiol composition of the present disclosure; and mixing the polythiol composition, which includes at least the produced polythiol composition, with a polyisocyanate to obtain a polymerizable composition containing a polythiol composition, a polyisocyanate, and other optional components, and may further include other steps as needed.

[0099] The method for producing a polymerizable composition according to the present disclosure involves, in the step of producing a polythiol composition, using a thiourethane resin (for example, thiourethane resin in the grinding powder of a molded article of thiourethane resin) as a starting material to produce a polythiol composition, and in the step of obtaining a polymerizable composition, producing a polymerizable composition containing the polythiol composition produced above and a polyisocyanate compound. The resulting polymerizable composition can be used again in the production of thiourethane resin. In this way, the method for producing polymerizable compositions enables the effective utilization (i.e., recycling) of materials (i.e., thiourethane resin and its raw material, the polythiol composition).

[0100] Furthermore, as mentioned above, the method for producing the polythiol composition yields a polythiol composition with higher purity of the polythiol component as the main component compared to known methods (for example, a method for obtaining a polythiol composition by reacting a thiourethane resin with sodium hydroxide). The polymerizable composition obtained by the method for producing the polymerizable composition can be used to produce a resin with excellent properties [for example, 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 the polymerizable composition of this disclosure is particularly suitable as a composition for producing thiourethane resins for optical materials.

[0101] [Process for manufacturing the polythiol composition] For the process of producing the polythiol composition, the method for producing the polythiol composition described above can be appropriately referenced.

[0102] [Steps to obtain a polymerizable composition] In the step of obtaining a polymerizable composition, a polymerizable composition containing the polythiol composition and the polyisocyanate compound is obtained by mixing at least the polythiol composition and the polyisocyanate compound.

[0103] The preferred embodiment of the polyisocyanate compound used in the process of obtaining the polymerizable composition is the same as the preferred embodiment of the "polyisocyanate compound" described in the section on "polythiol composition".

[0104] In the process of obtaining a polymerizable composition, the mixing ratio of the polythiol composition and the polyisocyanate compound is not particularly limited. In the process of obtaining a polymerizable composition, the ratio of the mass of the polythiol composition to the mass of the polyisocyanate compound (i.e., mass [polythiol composition / polyisocyanate compound]) is preferably 0.10 to 10.00, 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 (mercapto group / isocyanato group) of the mercapto group of the polythiol compound and the isocyanate group of the polyisocyanate compound contained in the polythiol composition is preferably 0.5 to 3.0, more preferably 0.6 to 2.0, and particularly preferably 0.8 to 1.3.

[0105] In the process of obtaining the polymerizable composition, there are no particular restrictions on the total mass of the polythiol composition and the polyisocyanate compound charged, but it is preferably 60% by mass or more, more preferably 80% by mass or more, and particularly preferably 90% by mass or more, relative to the total amount of polymerizable composition produced.

[0106] 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 polyisocyanate may be mixed with other components. Furthermore, in the process of obtaining a polymerizable composition, at least the polythiol composition and the polyisocyanate compound may be mixed, and then other components may be added to the mixture. Other components are not particularly limited and may include, for example, polymerization catalysts, internal 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 whitening agents, fluorescent pigments, inorganic pigments, and the like.

[0107] <Polymerization catalyst> There are no particular restrictions on the polymerization catalyst, and examples include tertiary amines, inorganic or organic acid salts of tertiary amines, metal compounds such as dimethyltin dichloride, quaternary ammonium salts, and organic sulfonic acids. These may be used individually or in combination of two or more.

[0108] <Internal release agent> There are no particular restrictions on the internal release agent; for example, acidic phosphate esters such as phosphate monoesters and phosphate diesters can be used. These may be used individually or in combination of two or more types.

[0109] <Resin modifier> There are no particular restrictions on the resin modifiers, and examples include episulfides, epoxy, organic acids, anhydrides of organic acids, (meth)acrylates, olefins, etc. These may be used individually or in combination of two or more types. Note that (meth)acrylate means at least one of acrylate and methacrylate.

[0110] In the process of obtaining a polymerizable composition, the mixing of the above-mentioned components can be carried out according to conventional methods, and the method of mixing is not particularly limited.

[0111] [Method of manufacturing resin] The present disclosure's method for producing a resin includes the steps of: producing a polymerizable composition by the method for producing a polymerizable composition described above; and obtaining a resin by curing the polymerizable composition. The resin manufacturing method of this disclosure may include other steps as necessary. The resin manufacturing method of this disclosure provides the same effects as the method for manufacturing the polymerizable composition of this disclosure described above.

[0112] The resin produced by the resin production method of this disclosure is a thiourethane resin, but in order to distinguish it from thiourethane resin, which is one of the starting materials for polythiol compositions, it is simply referred to as "resin" in this disclosure.

[0113] In the process of obtaining the resin, the polymerizable composition is cured to obtain the resin. The polymerizable composition described above can be cured 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 treatments such as filtration and degassing. The polymerization conditions (e.g., polymerization temperature, polymerization time, etc.) for polymerizing the monomers in the above polymerizable composition are set appropriately, 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 described later is used, the properties of the mold. There are no particular restrictions on the polymerization temperature, but it is preferably -50 to 150°C, and more preferably 10 to 150°C. There are no particular restrictions on the polymerization time, but it is preferably 1 to 200 hours, and more preferably 1 to 80 hours.

[0114] The process of obtaining the resin may involve subjecting the polymer obtained by monomer polymerization to a treatment such as annealing. There are no particular restrictions on the annealing temperature, but it is preferably 50 to 150°C, more preferably 90 to 140°C, and most preferably 100 to 130°C.

[0115] [[Manufacturing method for molded products]] A method for manufacturing a molded article is a method for manufacturing a molded article containing a resin, comprising the steps of: manufacturing a polymerizable composition by the method for manufacturing a polymerizable composition described above; and obtaining a molded article containing a resin by curing the polymerizable composition, and may optionally include other steps. The method for producing the molded article yields the same effects as the method for producing the polymerizable composition described above.

[0116] In the process of obtaining a molded article containing resin, the polymerizable composition is cured to obtain a molded article containing resin. Preferred conditions for curing the above polymerizable composition, that is, for polymerization of monomers in the above polymerizable composition, can be appropriately referred to in the section on "Method for Producing Resins".

[0117] One example of polymerization in this process is casting polymerization. In casting polymerization, the polymerizable composition is first injected between molds held together by gaskets or tape. Degassing and filtration treatments may be performed as needed. Next, the monomers in the polymerizable composition injected between the molding molds are polymerized, thereby curing the composition between the molding molds to obtain a cured product. Then, the cured product is removed from the molding molds to obtain a molded body containing resin. Polymerization of the above monomers may be carried out by heating the polymerizable composition. This heating can be performed, for example, using a heating device equipped with a mechanism for heating the object to be heated in an oven, water, or the like.

[0118] [Manufacturing methods for optical materials, manufacturing methods for lenses] A method for manufacturing an optical material (e.g., a lens) is a method for manufacturing an optical material (e.g., a lens) including a molded body containing a resin, and includes the steps of: manufacturing a polymerizable composition by the method for manufacturing a polymerizable composition described above; and obtaining a molded body containing a resin by curing the polymerizable composition, and may include other steps as needed. The method for producing optical materials yields the same effects as the method for producing polymerizable compositions described above.

[0119] The method for manufacturing optical materials is an application of the method for manufacturing molded products. For example, in a method for manufacturing a molded article, by appropriately selecting the shape of the molding mold used in the aforementioned casting polymerization, a molded article applicable to optical materials (e.g., lenses) can be obtained.

[0120] Examples of optical materials include lenses (e.g., eyeglass lenses, camera lenses, polarizing lenses) and light-emitting diodes (LEDs).

[0121] A method for manufacturing optical materials (e.g., lenses) may include a step of forming a coating layer on one or both sides of a molded body containing resin.

[0122] Examples of coating layers include primer layers, hard coat layers, anti-reflective layers, anti-fogging layers, anti-stain layers, and water-repellent layers. These coating layers may be formed individually or as a multilayer structure of multiple coating layers. When coating layers are formed on both sides, similar coating layers may be formed on each side, or different coating layers may be formed on each side.

[0123] The components of the coating layer can be selected as appropriate depending on the purpose. The components of the coating layer include, for example, resins such as urethane resin, epoxy resin, polyester resin, melamine resin, and polyvinyl acetal resin; infrared absorbers; light stabilizers; antioxidants; photochromic compounds; dyes; pigments; and antistatic agents.

[0124] For eyeglass lenses and coating layers, you can refer to publicly available documents such as International Publication No. 2017 / 047745 as appropriate.

[0125] [[Polymerizable composition]] The polymerizable composition contains a polythiol composition obtained by a method for producing a polythiol composition, and a polyisocyanate compound. Polymerizable compositions can be produced by the method for producing polymerizable compositions described above. The polymerizable composition provides the same effects as the method for producing the polymerizable composition described above. Preferred embodiments of the polymerizable composition can be appropriately referenced from the method for producing the polymerizable composition described above. However, the input mass [polythiol composition / polyisocyanate compound] shall be read as the content mass ratio [polythiol composition / polyisocyanate compound], and the total input mass of the polythiol composition and polyisocyanate compound shall be read as the total content mass of the polythiol composition and polyisocyanate compound.

[0126] [[Resins, molded products, optical materials (e.g., lenses)]] The resin is a cured product of the polymerizable composition described above. The molded article is a molded article containing the resin described above. The optical material (e.g., lens) is an optical material (e.g., lens) that contains the resin mentioned above. Resins, molded articles, and optical materials (e.g., lenses) can achieve the same effects as those described above for the method of producing polymerizable compositions.

[0127] Resins, molded articles, and optical materials (e.g., lenses) can be manufactured by the methods described above for manufacturing resins, molded articles, and optical materials (e.g., lenses), respectively. Preferred embodiments of the resin, molded article, and optical material (e.g., lens) can be referenced to preferred embodiments of the method for manufacturing the resin, the method for manufacturing the molded article, and the method for manufacturing the optical material (e.g., lens), respectively.

[0128] <Preferred performance of resin or molded article> There are no particular restrictions on the glass transition temperature Tg of the resin (or molded article), but from the viewpoint of heat resistance, it is preferably 70°C or higher, more preferably 80°C or higher, and especially preferably 85°C or higher. There is no particular upper limit to the glass transition temperature Tg; it may be 130°C or lower, 120°C or lower, or 110°C or lower. There are no particular restrictions on the glass transition temperature Tg, but it is preferably 70°C to 130°C, more preferably 80°C to 120°C, and most preferably 85°C to 110°C.

[0129] There are no particular restrictions on the refractive index (ne) of the resin (or molded article), but from the viewpoint of application to optical materials, it is preferably 1.500 or higher, more preferably 1.540 or higher, and particularly preferably 1.590 or higher. There is no particular upper limit to the refractive index (ne) mentioned above, but it is preferably 1.750. There are no particular restrictions on the refractive index (ne) mentioned above, but it is preferably 1.500 to 1.750, more preferably 1.540 to 1.750, and especially preferably 1.590 to 1.750.

[0130] There are no particular restrictions on the Abbe number of the resin (or molded article), but from the viewpoint of application to optical materials, it is preferably 28 or higher, more preferably 30 or higher. There is no particular upper limit to the Abbe number mentioned above, but it is preferably 50, and more preferably 45. There are no particular restrictions on the Abbe number mentioned above, but it is preferably 28 to 50, and more preferably 30 to 45.

[0131] There are no particular restrictions on the specific gravity of the resin (or molded article), but from the viewpoint of application to optical materials, it is preferably 1.10 or higher, and more preferably 1.20 or higher. There is no particular upper limit to the specific gravity mentioned above, but it is preferably 1.50, and more preferably 1.40. There are no particular restrictions on the specific gravity, but it is preferably 1.10 to 1.50, and more preferably 1.20 to 1.40.

[0132] This disclosure may use any combination of the examples, contents, and various physical properties of the above-mentioned components as described in the detailed description of the invention as examples or preferred ranges. Furthermore, by adjusting the compositions described in the examples to those described in the detailed description of the invention, the invention can be carried out in the same manner as in the examples across the entire claimed compositional range. [Examples]

[0133] The present disclosure will be further described below with reference to examples. However, the present disclosure is not limited to the embodiments shown in the examples.

[0134] [Manufacturing Example 1] <Manufacturing of molded articles containing thiourethane resin> In a flask equipped with a stirring device, dimethyltin dichloride (0.0075 parts by mass per 100 parts by mass of the total amount of the polyisocyanate compound and the polythiol composition below), JP-506H (manufactured by Johoku Kagaku Kogyo Co., Ltd.; acidic phosphate ester) (0.15 parts by mass per 100 parts by mass of the total amount of the polyisocyanate compound and the polythiol composition below), and m-xylylene diisocyanate (XDI) (49.6 parts by mass), a polyisocyanate compound, were added. After stirring until all additives were sufficiently dissolved, a polythiol composition (50.4 parts by mass) 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 was added and mixed to obtain a polymerizable composition, which is a transparent, homogeneous solution. This polymerizable composition was degassed at 300 Pa for 30 minutes or more, and then filtered through a polytetrafluoroethylene (PTFE) filter with a pore size of 5 μm. Subsequently, it was injected into a mold consisting of a glass mold and gasket having the desired lens shape. The mold into which the polymerizable composition was injected was polymerized in an oven for 24 hours at a temperature range of 10°C to 120°C, depending on the shape of the lens. The mold was removed from the oven and demolded to obtain a spectacle lens molded from an optical component resin. The obtained molded body was annealed at 120°C for 2 hours.

[0135] <Manufacturing of thiourethane resin powder> Lenses were manufactured by machining the molded body obtained above. The resulting machining dust 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.

[0136] [Example 1-1] <Decomposition of thiourethane resin by tetramethylammonium hydroxide and ethanol> (Reaction process) 15.0 g of 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. A 25% by mass aqueous solution of tetramethylammonium hydroxide (TMAH) as a quaternary ammonium salt (43.8 g; 0.12 mol) and ethanol as an alcohol (55.3 g; 1.2 mol) were added thereto, and the mixture was heated and stirred at 40°C (reaction temperature) for 6 hours (reaction time) to obtain a reaction mixture containing the polythiol composition (end of reaction process). The water content (43.8 × 0.75) in the reaction system (15.0 + 55.3 + 43.8) was 28.8% by mass (43.8 × 0.75 / (15.0 + 55.3 + 43.8) × 100).

[0137] (separation process) The reaction mixture obtained in the above reaction step was cooled to room temperature, and then solid matter was removed by filtration. To the obtained filtrate, toluene (45.0 g) was added as a separation solvent. The resulting 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. 28% by mass sodium methoxide methanol solution (16.4 g; 0.085 mol) was added to the resulting liquid 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, after which 21 g of 1 M hydrochloric acid was added and stirred. From the resulting aqueous liquid, soluble components were extracted 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 the polythiol composition. From the obtained toluene solution, highly polar by-products were removed by silica gel column chromatography, and then toluene was removed by distillation using a rotary evaporator. The resulting mixture was subjected to removal of low-boiling-point components by vacuum pump chromatography, followed by filtration using a 1-micron PTFE membrane filter, in that order to obtain 3.1 g (yield: 41% by 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) (separation step).

[0138] [Examples 1-2] In Example 1-1, the reaction and separation steps were carried out in the same manner as in Example 1-1, except that the reaction temperature was set to room temperature (15°C) instead of 40°C. As a result, 0.6 g of the polythiol composition (yield: 8% by mass) was obtained. The water content in the reaction system was 28.8% by mass.

[0139] [Examples 1-3] In Example 1-1, the reaction and separation steps were carried out in the same manner as in Example 1-1, except that the reaction temperature was changed from 40°C to 60°C. As a result, 3.2 g of the polythiol composition (yield: 42% by mass) was obtained. The water content in the reaction system was 28.8% by mass.

[0140] [Examples 1-4] In Example 1-1, the reaction and separation steps were carried out in the same manner as in Example 1-1, except that the heating setting temperature was set to 110°C and heated until flux occurred, instead of using a reaction temperature of 40°C in the reaction step. As a result, 3.7 g of the polythiol composition (yield: 49% by mass) was obtained. The water content in the reaction system was 28.8% by mass.

[0141] [Example 2-1] In Example 1-1, methanol (38.4 g; 1.2 mol) was used instead of ethanol (55.3 g; 1.2 mol) in the reaction step, but the reaction and separation steps were carried out in the same manner as in Example 1-1. As a result, 1.8 g of the polythiol composition was obtained (yield: 24% by mass). The water content (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).

[0142] [Example 2-2] In Example 2-1, the reaction and separation steps were carried out in the same manner as in Example 2-1, except that the reaction temperature was set to room temperature (15°C) instead of 40°C. As a result, 0.5 g of the polythiol composition (yield: 6% by mass) was obtained. The water content in the reaction system was 33.8% by mass.

[0143] [Examples 2-3] In Example 2-1, the reaction and separation steps were carried out in the same manner as in Example 2-1, except that the reaction temperature was changed from 40°C to 60°C. As a result, 3.9 g of the polythiol composition (yield: 51% by mass) was obtained. The water content in the reaction system was 33.8% by mass.

[0144] [Examples 2-4] In Example 2-1, the reaction and separation steps were carried out in the same manner as in Example 2-1, except that the heating setting temperature was set to 110°C and heated until flux occurred, instead of using a reaction temperature of 40°C in the reaction step. As a result, 4.1 g of the polythiol composition (yield: 54% by mass) was obtained. The water content in the reaction system was 33.8% by mass.

[0145] [Example 3-1] In Example 1-1, the reaction and separation steps 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. As a result, 1.8 g of the polythiol composition was obtained (yield: 24% by mass). The water content (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).

[0146] [Example 3-2] In Example 3-1, the reaction and separation steps were carried out in the same manner as in Example 3-1, except that the reaction temperature was set to room temperature (15°C) instead of 40°C. As a result, 0.3 g of the polythiol composition (yield: 4% by mass) was obtained. The water content in the reaction system was 25.1% by mass.

[0147] [Example 3-3] In Example 3-1, the reaction and separation steps were carried out in the same manner as in Example 3-1, except that the reaction temperature was changed from 40°C to 60°C. As a result, 2.1 g of the polythiol composition (yield: 27% by mass) was obtained. The water content in the reaction system was 25.1% by mass.

[0148] [Examples 3-4] In Example 3-1, the reaction and separation steps were carried out in the same manner as in Example 3-1, except that the heating setting temperature was set to 110°C and heated until flux occurred, instead of using a reaction temperature of 40°C in the reaction step. As a result, 2.5 g of the polythiol composition (yield: 33% by mass) was obtained. The water content in the reaction system was 25.1% by mass.

[0149] [Example 4-1] In Example 1-1, the reaction and separation steps were carried out in the same manner as in Example 1-1, except that benzyl alcohol (129.8 g; 1.2 mol) was used instead of ethanol (55.3 g; 1.2 mol) in the reaction step. As a result, 2.8 g of the polythiol composition was obtained (yield: 37% by mass). The water content (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).

[0150] [Example 4-2] In Example 4-1, the reaction and separation steps were carried out in the same manner as in Example 4-1, except that the reaction temperature was set to room temperature (15°C) instead of 40°C. As a result, 0.3 g of the polythiol composition (yield: 4% by mass) was obtained. The water content in the reaction system was 17.4% by mass.

[0151] [Example 4-3] In Example 4-1, the reaction and separation steps were carried out in the same manner as in Example 4-1, except that the reaction temperature was changed from 40°C to 60°C. As a result, 3.1 g of the polythiol composition (yield: 42% by mass) was obtained. The water content in the reaction system was 17.4% by mass.

[0152] [Example 4-4] In Example 4-1, the reaction and separation steps were carried out in the same manner as in Example 4-1, except that the reaction temperature was changed from 40°C to 110°C. As a result, 3.5 g of the polythiol composition (yield: 47% by mass) was obtained. The water content in the reaction system was 17.4% by mass.

[0153] [Example 5-1] In Example 2-1, the reaction and separation steps were carried out in the same manner as in Example 2-1, except that water was not used in the reaction step (a 10% by mass tetramethylammonium hydroxide (TMAH) methanol solution was used instead of a 25% by mass tetramethylammonium hydroxide (TMAH) aqueous solution). As a result, 2.4 g of the polythiol composition was obtained (yield: 32% by mass). The water content in the reaction system was 0.0% by mass.

[0154] [Example 5-2] In Example 5-1, the reaction and separation steps were carried out in the same manner as in Example 5-1, except that the reaction temperature was set to room temperature (15°C) instead of 40°C. As a result, 0.7 g of the polythiol composition (yield: 10% by mass) was obtained. The water content in the reaction system was 0.0% by mass.

[0155] [Example 5-3] In Example 5-1, the reaction and separation steps were carried out in the same manner as in Example 5-1, except that the reaction temperature was changed from 40°C to 60°C. As a result, 2.9 g of the polythiol composition (yield: 38% by mass) was obtained. The water content in the reaction system was 0.0% by mass.

[0156] [Example 5-4] In Example 5-1, the reaction and separation steps were carried out in the same manner as in Example 5-1, except that methanol (38.4 g; 1.2 mol) was used in the reaction step instead of methanol (98.4 g; 3.1 mol) + ethanol (55.2 g; 1.2 mol) (molar ratio (methanol:ethanol) = 5:2)). As a result, 1.2 g of the polythiol composition was obtained (yield: 16% by mass). The water content in the reaction system was 0.0% by mass.

[0157] [Example 6-1] In Example 2-1, the reaction and separation steps were carried out in the same manner as in Example 2-1, except that a 10% by mass aqueous solution of tetraethylammonium hydroxide (TEAH) (176.7 g; 0.12 mol) was used instead of a 25% by mass aqueous solution of tetramethylammonium hydroxide (TMAH) (43.8 g; 0.12 mol) as the quaternary ammonium salt aqueous solution in the reaction step. As a result, 2.6 g of the polythiol composition was obtained (yield: 35% by mass). The water content (176.7 × 0.9) in the reaction system (15.0 + 38.4 + 176.7) was 69.1% by mass (176.7 × 0.9 / (15.0 + 38.4 + 176.7) × 100).

[0158] [Example 6-2] In Example 1-1, the reaction and separation steps were carried out in the same manner as in Example 1-1, except that a 10% by mass aqueous solution of tetraethylammonium hydroxide (TEAH) (176.7 g; 0.12 mol) was used instead of a 25% by mass aqueous solution of tetramethylammonium hydroxide (TMAH) (43.8 g; 0.12 mol) as the quaternary ammonium salt aqueous solution in the reaction step. As a result, 2.7 g of the polythiol composition was obtained (yield: 35% by mass). The water content (176.7 × 0.9) in the reaction system (15.0 + 55.3 + 176.7) was 64.4% by mass (176.7 × 0.9 / (15.0 + 55.3 + 176.7) × 100).

[0159] [Example 6-3] In Example 3-1, the reaction and separation steps were carried out in the same manner as in Example 3-1, except that a 10% by mass aqueous solution of tetraethylammonium hydroxide (TEAH) (176.7 g; 0.12 mol) was used instead of a 25% by mass aqueous solution of tetramethylammonium hydroxide (TMAH) (43.8 g; 0.12 mol) as the quaternary ammonium salt aqueous solution in the reaction step. As a result, 2.2 g of the polythiol composition (yield: 29% by mass) was obtained. The water content (176.7 × 0.9) in the reaction system (15.0 + 72.1 + 70.7) was 60.3% by mass (176.7 × 0.9 / (15.0 + 72.1 + 176.7) × 100).

[0160] [Example 6-4] In Example 4-1, the reaction and separation steps were carried out in the same manner as in Example 4-1, except that a 10% by mass aqueous solution of tetraethylammonium hydroxide (TEAH) (70.7 g; 0.12 mol) was used instead of a 25% by mass aqueous solution of tetramethylammonium hydroxide (TMAH) (43.8 g; 0.12 mol) as the quaternary ammonium salt aqueous solution in the reaction step. As a result, 0.7 g of the polythiol composition (yield: 10% by mass) was obtained. The water content (176.7 × 0.9) in the reaction system (15.0 + 129.8 + 70.7) was 49.5% by mass (176.7 × 0.9 / (15.0 + 129.8 + 176.7) × 100).

[0161] [Example 7-1] In Example 2-1, the reaction and separation steps were carried out in the same manner as in Example 2-1, except that a 40% by mass aqueous solution of tetrabutylammonium hydroxide (TBAOH) (77.84 g; 0.12 mol) was used instead of a 25% by mass aqueous solution of tetramethylammonium hydroxide (TMAH) (43.8 g; 0.12 mol) as the quaternary ammonium salt aqueous solution in the reaction step. As a result, 2.3 g of the polythiol composition was obtained (yield: 30% by mass). The water content (124.6 × 0.75) in the reaction system (15.0 + 38.4 + 77.84) was 35.6% by mass (77.84 × 0.6 / (15.0 + 38.4 + 77.84) × 100).

[0162] [Example 7-2] In Example 1-1, the reaction and separation steps were carried out in the same manner as in Example 1-1, except that a 40% by mass aqueous solution of tetrabutylammonium hydroxide (TBAOH) (77.84 g; 0.12 mol) was used instead of a 25% by mass aqueous solution of tetramethylammonium hydroxide (TMAH) (43.8 g; 0.12 mol) as the quaternary ammonium salt aqueous solution in the reaction step. As a result, 2.0 g of the polythiol composition (yield: 27% by mass) was obtained. The water content (77.84 × 0.6) in the reaction system (15.0 + 55.3 + 77.84) was 31.5% by mass (77.84 × 0.6 / (15.0 + 55.3 + 77.84) × 100).

[0163] [Example 7-3] In Example 3-1, the reaction and separation steps were carried out in the same manner as in Example 3-1, except that a 40% by mass aqueous solution of tetrabutylammonium hydroxide (TBAOH) (77.84 g; 0.12 mol) was used instead of a 25% by mass aqueous solution of tetramethylammonium hydroxide (TMAH) (43.8 g; 0.12 mol) as the quaternary ammonium salt aqueous solution in the reaction step. As a result, 1.5 g of the polythiol composition was obtained (yield: 19% by mass). The water content (124.6 × 0.75) in the reaction system (15.0 + 72.1 + 124.6) was 28.3% by mass (77.84 × 0.6 / (15.0 + 72.1 + 77.84) × 100).

[0164] [Example 7-4] In Example 4-1, the reaction and separation steps were carried out in the same manner as in Example 4-1, except that a 40% by mass aqueous solution of tetrabutylammonium hydroxide (TBAOH) (77.84 g; 0.12 mol) was used instead of a 25% by mass aqueous solution of tetramethylammonium hydroxide (TMAH) (43.8 g; 0.12 mol) as the quaternary ammonium salt aqueous solution in the reaction step. As a result, 1.0 g of the polythiol composition (yield: 13% by mass) was obtained. The water content (124.6 × 0.75) in the reaction system (15.0 + 129.8 + 124.6) was 21.0% by mass (77.84 × 0.6 / (15.0 + 129.8 + 77.84) × 100).

[0165] [Examples 7-5] In Example 1-1, the reaction and separation steps were carried out in the same manner as in Example 1-1, except that instead of using a 25% by mass aqueous solution of tetramethylammonium hydroxide (TMAH) (43.8 g; 0.12 mol) and ethanol (53.1 g) as quaternary ammonium salt aqueous solutions in the reaction step, a 40% by mass aqueous solution of tetrabutylammonium hydroxide (TBAOH) (77.84 g; 0.12 mol) and toluene (180.0 g) were used. As a result, 2.4 g of the polythiol composition was obtained (yield: 32% by mass). The water content (77.84 × 0.6) in the reaction system (15.0 + 55.3 + 77.84) was 17.1% by mass (77.84 × 0.6 / (15.0 + 180.0 + 77.84) × 100).

[0166] [Example 8-1] In Example 2-1, the reaction and separation steps were carried out in the same manner as in Example 2-1, except that a 40% by mass aqueous solution of benzyltrimethylammonium hydroxide (50.2 g; 0.12 mol) was used instead of a 25% by mass aqueous solution of tetramethylammonium hydroxide (TMAH) (43.8 g; 0.12 mol) as the quaternary ammonium salt aqueous solution in the reaction step. As a result, 1.7 g of the polythiol composition was obtained (yield: 23% by mass). The water content (50.2 × 0.6) in the reaction system (15.0 + 38.4 + 50.2) was 29.1% by mass (50.2 × 0.6 / (15.0 + 38.4 + 50.2) × 100).

[0167] [Example 8-2] In Example 1-1, the reaction and separation steps were carried out in the same manner as in Example 1-1, except that a 40% by mass aqueous solution of benzyltrimethylammonium hydroxide (50.2 g; 0.12 mol) was used instead of a 25% by mass aqueous solution of tetramethylammonium hydroxide (TMAH) (43.8 g; 0.12 mol) as the quaternary ammonium salt aqueous solution in the reaction step. As a result, 1.8 g of the polythiol composition (yield: 24% by mass) was obtained. The water content (50.2 × 0.6) in the reaction system (15.0 + 55.3 + 50.2) was 25.0% by mass (50.2 × 0.6 / (15.0 + 55.3 + 50.2) × 100).

[0168] [Example 8-3] In Example 3-1, the reaction and separation steps were carried out in the same manner as in Example 3-1, except that a 40% by mass aqueous solution of benzyltrimethylammonium hydroxide (50.2 g; 0.12 mol) was used instead of a 25% by mass aqueous solution of tetramethylammonium hydroxide (TMAH) (43.8 g; 0.12 mol) as the quaternary ammonium salt aqueous solution in the reaction step. As a result, 1.0 g of the polythiol composition was obtained (yield: 13% by mass). The water content (50.2 × 0.6) in the reaction system (15.0 + 72.1 + 50.2) was 21.9% by mass (50.2 × 0.6 / (15.0 + 72.1 + 50.2) × 100).

[0169] [Example 8-4] In Example 4-1, the reaction and separation steps were carried out in the same manner as in Example 4-1, except that a 40% by mass aqueous solution of benzyltrimethylammonium hydroxide (50.2 g; 0.12 mol) was used instead of a 25% by mass aqueous solution of tetramethylammonium hydroxide (TMAH) (43.8 g; 0.12 mol) as the quaternary ammonium salt aqueous solution in the reaction step. As a result, 0.7 g of the polythiol composition (yield: 10% by mass) was obtained. The water content (50.2 × 0.6) in the reaction system (15.0 + 129.8 + 50.2) was 15.4% by mass (50.2 × 0.6 / (15.0 + 129.8 + 50.2) × 100).

[0170] [Comparative Example 1-1] <Decomposition of thiourethane resin by monoethanolamine> (Reaction process) 15.0 g of thiourethane resin powder obtained in Production Example 1 was weighed and placed entirely into a 300 mL flask equipped with a condenser. Monoethanolamine (7.4 g; 0.12 mol) as an amine compound and alcohol, and toluene (180.0 g) as a reaction solvent were added. The mixture was heated and stirred at 40°C (reaction temperature) for 6 hours (reaction time) to obtain a reaction mixture containing the polythiol composition (end of reaction process). The water content in the reaction system was 0.0% by mass.

[0171] (separation process) The reaction mixture obtained in the above reaction step was cooled to room temperature, and then solid matter was removed by filtration. The resulting 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. Highly polar by-products were removed from the resulting toluene solution by silica gel column, and then toluene was removed by distillation using a rotary evaporator. The resulting mixture was subjected to the removal of low-boiling-point components using a vacuum pump, followed by filtration using a 1-micron PTFE membrane filter, in that order to obtain 0.2 g (yield: 3% by 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) (separation step).

[0172] [Comparative Example 1-2] In Comparative Example 1-1, the reaction and separation steps were carried out in the same manner as in Comparative Example 1-1, except that the reaction temperature was set to room temperature (15°C) instead of 40°C. As a result, 0.0 g of the polythiol composition (yield: 0% by mass) was obtained. The water content in the reaction system was 0.0% by mass.

[0173] [Comparative Examples 1-3] In Comparative Example 1-1, the reaction and separation steps were carried out in the same manner as in Comparative Example 1-1, except that the reaction temperature was set to 60°C instead of 40°C. As a result, 2.4 g of the polythiol composition (yield: 32% by mass) was obtained. The water content in the reaction system was 0.0% by mass.

[0174] [Comparative Examples 1-4] In Comparative Example 1-1, the reaction and separation steps were carried out in the same manner as in Comparative Example 1-1, except that the reaction temperature was set to 110°C instead of 40°C. As a result, 5.8 g of the polythiol composition (yield: 76% by mass) was obtained. The water content in the reaction system was 0.0% by mass.

[0175] [Evaluation of yield] Table 1 shows the yields for Examples 1-1 to 8-4 and Comparative Examples 1-1 to 1-4.

[0176] [Table 1]

[0177] As can be seen from Table 1 above, the methods for producing polythiol compositions in Examples 1-1 to 8-4, which include a reaction step of reacting a thiourethane resin with a quaternary ammonium salt consisting of a quaternary ammonium cation and a counteranion to produce a polythiol composition, allow for the production of polythiol compositions using thiourethane resin as a starting material in a wide temperature range (15 to 110°C), including the low temperature range.

[0178] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of this disclosure is indicated by the claims rather than the foregoing description, and all modifications within the meaning and scope equivalent to the claims are intended. This disclosure may use any combination of the examples, contents, and various physical properties of the above-mentioned components as described in the detailed description of the invention as examples or preferred ranges. Furthermore, by adjusting the compositions described in the examples to match those described in the detailed description of the invention, the disclosed embodiments can be implemented in the same manner as the examples across the entire claimed composition range.

Claims

1. The process includes a reaction step of reacting a thiourethane resin with a quaternary ammonium salt consisting of a quaternary ammonium cation and a counteranion to produce a polythiol composition. A method for producing a polythiol composition, wherein the reaction temperature between the thiourethane resin and the quaternary ammonium salt in the reaction step is 15 to 110°C.

2. The method for producing the polythiol composition according to claim 1, wherein the counteranion is a hydroxide ion.

3. A method for producing a polythiol composition according to claim 1 or 2, wherein the reaction system in the reaction step further comprises an alcohol.

4. The method for producing a polythiol composition according to claim 3, wherein the alcohol comprises one or more alcohols that are miscible with water.

5. The quaternary ammonium cation is NR ４ ＋ A method for producing a polythiol composition according to claim 1 or 2, wherein the four R groups are all the same group.

6. The quaternary ammonium cation is NR ４ ＋ A method for producing a polythiol composition according to claim 1 or 2, wherein the polythiol composition is represented as such, and three of the four R groups are the same group, and the remaining one of the four R groups is a different group from the aforementioned same group.

7. The quaternary ammonium cation is NR ４ ＋ A method for producing a polythiol composition according to claim 1 or 2, wherein the four Rs are each independently selected from the group consisting of alkyl groups, aromatic groups, heteroaryl groups, and ether-containing groups.

8. The method for producing the polythiol composition according to claim 7, wherein the alkyl group has 1 to 20 carbon atoms and is linear, branched, or cyclic.

9. A method for producing a polymerizable composition, comprising the steps of: producing a polythiol composition by the method for producing a polythiol composition described in claim 1 or 2; and mixing the polythiol composition containing the produced polythiol composition with a polyisocyanate compound to obtain a polymerizable composition containing the polythiol composition and the polyisocyanate compound.

10. A method for producing a resin, comprising the steps of: producing a polymerizable composition by the method for producing a polymerizable composition described in claim 9; and obtaining a resin by curing the polymerizable composition.

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