Composition, and optical material and lens using the same

Abstract

Provided is a composition from which an optical material having a high refractive index and an excellent color tone is obtained.　This composition contains a polythiol (b) and a compound (a) represented by formula (1) (in the formula, Ar represents an aromatic ring, m represents an integer of 2-8 and n represents an integer of 0-6 but m+n is not more than the number of carbon atoms forming the aromatic ring, each R1 independently represents an alkylthio group, an epoxy alkylthio group, a thiol group, a halogen group, a hydroxy group, a dialkyl thiocarbamoyl group, or a dialkyl carbamoylthio group).

Description

[Technical Field]

[0001] The present invention relates to a composition and an optical material and a lens using the same. [Background technology]

[0002] Optical materials, particularly those used for eyeglass lenses, are required to have optical properties such as heat resistance, low specific gravity, high transparency, low yellowness index, high refractive index, and high Abbe number. In recent years, there has been a demand for even higher performance, and optical materials with high refractive index and high Abbe number are particularly in demand.

[0003] Polymerizable compositions for optical materials using episulfide compounds have attracted attention as materials for achieving high refractive indexes and high Abbe numbers. For example, Patent Document 1 describes an invention relating to a polymerizable composition containing a thioepoxy compound having one or more disulfide bonds in the molecule, which results in a cured resin with a refractive index (nd) of 1.71 or higher. In this case, it is described that bis(2,3-epithiopropyl)disulfide is the most preferred thioepoxy compound having one or more disulfide bonds in the molecule. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-194083 Summary of the Invention [Problem to be solved by the invention]

[0005] The polymerizable composition described in Patent Document 1 can produce optical materials with high refractive indexes. However, optical materials with even higher refractive indexes are desired. It has also been found that the higher the refractive index of an optical material, the worse the color tone may be. Therefore, the present invention provides a composition that can produce optical materials with high refractive indexes and excellent color tone. [Means for solving the problem]

[0006] The present inventors have conducted extensive research to solve the above-mentioned problems. As a result, they have found that the above-mentioned problems can be solved by combining an episulfide compound and a polythiol compound having an aromatic skeleton, and have thus completed the present invention. That is, the present invention is, for example, as follows.

[0007] [1] Formula (1): [ka] [In the above formula, Ar represents an aromatic ring; m represents an integer of 2 to 8; n represents an integer of 0 to 6, However, m+n is equal to or less than the number of carbon atoms constituting the aromatic ring, R 1 each independently represents an alkylthio group, an epoxyalkylthio group, a thiol group, a halogen group, a hydroxy group, a dialkylthiocarbamoyl group, or a dialkylcarbamoylthio group. A composition comprising a compound (a) represented by the formula: and a polythiol (b). [2] The composition according to [1] above, wherein Ar is an aromatic ring consisting of carbon and hydrogen. [3] The composition according to [1] or [2] above, wherein m is 2 or 3. [4] The composition according to any one of the above [1] to [3], wherein m+n is 2 to 6. [5] The composition according to any one of the above [1] to [4], wherein the content of the compound (a) is 5 to 95 mass % based on the total mass of the composition. [6] The polythiol (b) is selected from the group consisting of 1,2,6,7-tetramercapto-4-thiaheptane, methanedithiol, (sulfanylmethyldisulfanyl)methanethiol, bis(2-mercaptoethyl)sulfide, 2,5-bis(mercaptomethyl)-1,4-dithiane, 1,2-bis(2-mercaptoethylthio)-3-mercaptopropane, 4,8-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 4,7-dimercaptomethyl-1,11 The composition according to any one of the above [1] to [5], which contains at least one selected from the group consisting of 1,3-dimercapto-3,6,9-trithiaundecane, 5,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 1,1,3,3-tetrakis(mercaptomethylthio)propane, tetramercaptopentaerythritol, 1,3-bis(mercaptomethyl)benzene, 1,4-bis(mercaptomethyl)benzene, and thiiranemethanethiol. [7] Formula (2): [ka] [In the above formula, p represents an integer of 0 to 4; q is an integer between 0 and 2. The composition according to any one of the above [1] to [6], further comprising a compound (c) represented by the following formula: [8] The composition according to any one of the above [1] to [7], further comprising sulfur. [9] The composition according to any one of the above [1] to [8], further comprising a prepolymerization catalyst.

[10] The composition according to [9] above, wherein the prepolymerization catalyst comprises at least one selected from the group consisting of 2-mercapto-1-methylimidazole, 2-methyl-N-imidazole, and 1,2,2,6,6-pentamethylpiperidyl methacrylate.

[11] A pre-cured product obtained by pre-polymerizing the composition according to any one of the above [1] to

[10] .

[12] An optical material obtained by curing the composition according to any one of [1] to

[10] above or the pre-cured product according to

[11] above.

[13] An optical lens comprising the optical material according to

[12] above. [Effects of the Invention]

[0008] According to the present invention, there is provided a composition which can give an optical material having a high refractive index and excellent color tone. DETAILED DESCRIPTION OF THE INVENTION

[0009] The present invention will be described in detail below with reference to embodiments and examples, but the present invention is not limited to the embodiments and examples shown below, and can be modified and implemented as desired within the scope of the present invention.

[0010] <Composition> The composition according to the present invention contains a compound (a) represented by formula (1) and a polythiol (b), and may further contain a compound (c) represented by formula (2), sulfur, a polymerizable compound, a prepolymerization catalyst, a polymerization catalyst, a polymerization modifier, an additive, etc.

[0011] When the composition contains the compound (a) represented by formula (1), i.e., an episulfide compound having an aromatic skeleton, the refractive index of the resulting cured product (optical material) can be increased. Furthermore, when the composition contains the polythiol (b), the color tone of the resulting cured product (optical material) can be improved. By combining these, the refractive index and color tone of the resulting cured product (optical material) can be increased. Therefore, the composition is preferably a composition for optical materials.

[0012] [Compound (a)] The compound (a) is represented by the following formula (1).

[0013] [ka]

[0014] Ar represents an aromatic ring. Examples of the aromatic ring include an aromatic ring composed of carbon and hydrogen, and a heteroaromatic ring (an aromatic ring containing a heteroatom). Ar has 2 or more carbon atoms, preferably 2 to 18, more preferably 2 to 12, and even more preferably 3 to 6. Ar is preferably a 5-membered or 6-membered ring, and more preferably a 6-membered ring.

[0015] The aromatic ring consisting of carbon and hydrogen is not particularly limited, but examples thereof include a benzene ring, a naphthalene ring, a fluorene ring, an anthracene ring, a phenanthrene ring, etc. Among these, the aromatic ring consisting of carbon and hydrogen is preferably a benzene ring.

[0016] The heteroaromatic ring is not particularly limited, and examples thereof include a furan ring, a pyran ring, a pyrrole ring, an imidazole ring, a pyrazole ring, an oxazole ring, an isoxazole ring, a thiazole ring, an isothiazole ring, a triazole ring, a thiadiazole ring, a pyridine ring, a pyrazine ring, a pyrimidine ring, a pyridazine ring, a triazine ring, an indole ring, an isoindole ring, an indazole ring, a quinoline ring, an isoquinoline ring, a phthalazine ring, a phenanthridine ring, an acridine ring, etc. Among these, the heteroaromatic ring is preferably a furan ring, a pyrran ring, a pyrrole ring, an imidazole ring, a pyrazole ring, an oxazole ring, an isoxazole ring, a thiazole ring, an isothiazole ring, a triazole ring, a thiadiazole ring, a pyridine ring, a pyrazine ring, a pyrimidine ring, a pyridazine ring, or a triazine ring, more preferably a triazine ring or a thiadiazole ring, and even more preferably a thiadiazole ring.

[0017] Of the above, Ar is preferably an aromatic ring composed of carbon and hydrogen, and more preferably a benzene ring.

[0018] m represents an integer of 2 to 8, and is preferably 2, 3, or 6, more preferably 2 or 3, and even more preferably 3, from the viewpoint of color tone and ease of synthesis.

[0019] n represents an integer of 0 to 6, preferably 0 to 2, more preferably 0 or 1, and even more preferably 0.

[0020] m+n is equal to or less than the number of carbon atoms constituting the aromatic ring, and is preferably 2 to 6, more preferably 3 to 6, even more preferably 2 to 3, and particularly preferably 3. Note that "equal to or less than the number of carbon atoms constituting the aromatic ring" means that the number does not exceed the number of carbon atoms contained in the aromatic ring. For example, in the case of a benzene ring, which is an aromatic ring composed of carbon and hydrogen, the number of carbon atoms constituting the ring is 6, so m+n is 6 or less. Furthermore, in the case of a thiadiazole ring, which is a heteroaromatic ring, the number of carbon atoms constituting the ring is 2, so m+n is 2 or less.

[0021] R 1 each independently represents an alkylthio group, an epoxyalkylthio group, a thiol group, a halogen group, a hydroxy group, a dialkylthiocarbamoyl group, or a dialkylcarbamoylthio group.

[0022] The alkylthio group is not particularly limited, but examples thereof include a methylthio group, an ethylthio group, a propylthio group, a butylthio group, an isobutylthio group, a sec-butylthio group, a tert-butylthio group, a pentylthio group, and a hexylthio group.

[0023] The epoxyalkylthio group is not particularly limited, but may be a β-epoxypropylthio group.

[0024] The halogen group is not particularly limited, but examples thereof include a fluorine group (-F), a chlorine group (-Cl), a bromine group (-Br), and an iodine group (-I).

[0025] The dialkylthiocarbamoyl group is not particularly limited, but examples thereof include a dimethylthiocarbamoyl group, a diethylthiocarbamoyl group, and an ethylmethylthiocarbamoyl group.

[0026] In one embodiment, the compound (a) is represented by the following formula (1'):

[0027] [ka]

[0028] In formula (1′), m represents an integer of 2 to 6, and is preferably 2, 3, or 6, more preferably 2 or 3, and even more preferably 3, from the viewpoint of color tone and ease of synthesis.

[0029] In formula (1′), n represents an integer of 0 to 4, preferably 0 to 2, more preferably 0 or 1, and even more preferably 0.

[0030] In formula (1′), m+n is 6 or less (m+n≦6), preferably 2 to 6, more preferably 3 to 6, and even more preferably 3.

[0031] In formula (1'), R 1 is the same as the above formula (1).

[0032] Specific examples of compound (a) include, but are not limited to, bis(episulfide) compounds such as 1,3-bis(β-epithiopropylthio)benzene and 1,4-bis(β-epithiopropylthio)benzene; tris(episulfide) compounds such as 1,3,5-tris(β-epithiopropylthio)benzene, 1,2,4-tris(β-epithiopropylthio)benzene and 1,2,5-tris(β-epithiopropylthio)benzene; 1-methyl-3,5-bis(β-epithiopropylthio)benzene, 1-methyl-2,4-bis(β- Alkylthio-substituted bis(episulfide) compounds such as 1-(β-epoxypropylthio)-3,5-bis(β-epothiopropylthio)benzene, 1-methyl-2,5-bis(β-epothiopropylthio)benzene, 1-ethyl-3,5-bis(β-epothiopropylthio)benzene, and 1-t-butylthio-3,5-bis(β-epothiopropylthio)benzene; 1-(β-epoxypropylthio)-3,5-bis(β-epothiopropylthio)benzene, 1-(β-epoxypropylthio)-2,4-bis(β-epothiopropylthio)benzene, and 1-(β-epoxypropylthio)- Epoxyalkylthio group-substituted bis(episulfide) compounds such as 2,5-bis(β-epothiopropylthio)benzene; thiol group-substituted bis(episulfide) compounds such as 1-mercapto-3,5-bis(β-epothiopropylthio)benzene, 1-mercapto-2,4-bis(β-epothiopropylthio)benzene, and 1-mercapto-2,5-bis(β-epothiopropylthio)benzene; 1-fluoro-3,5-bis(β-epothiopropylthio)benzene, 1-chloro-3,5-bis(β-epothiopropylthio)benzene, Halogen-substituted bis(episulfide) compounds such as 1-bromo-3,5-bis(β-epothiopropylthio)benzene, 1-chloro-2,4-bis(β-epothiopropylthio)benzene, and 1-chloro-2,5-bis(β-epothiopropylthio)benzene; hydroxy-substituted bis(episulfide) compounds such as 1-hydroxy-3,5-bis(β-epothiopropylthio)benzene, 1-hydroxy-2,4-bis(β-epothiopropylthio)benzene, and 1-hydroxy-2,5-bis(β-epothiopropylthio)benzene;Dialkylthiocarbamoyl group-substituted bis(episulfide) compounds such as 1-dimethylthiocarbamoyl-3,5-bis(β-epothiopropylthio)benzene, 1-dimethylthiocarbamoyl-3,5-bis(β-epothiopropylthio)benzene, 1-dimethylthiocarbamoyl-2,4-bis(β-epothiopropylthio)benzene, and 1-dimethylthiocarbamoyl-2,5-bis(β-epothiopropylthio)benzene; dialkylcarbamoylthio group-substituted bis(episulfide) compounds such as 1-dimethylcarbamoylthio-3,5-bis(β-epothiopropylthio)benzene, 1-dimethylcarbamoylthio-3,5-bis(β-epothiopropylthio)benzene, 1-dimethylcarbamoylthio-2,4-bis(β-epothiopropylthio)benzene, and 1-dimethylcarbamoylthio-2,5-bis(β-epothiopropylthio)benzene;Examples of heterocyclic compounds include 2,5-bis(β-epithiopropylthio)-1,3,4-thiadiazole, 3,4-bis(β-epithiopropylthio)-1,2,5-thiadiazole, and 2,4,6-tris(β-epithiopropylthio)-1,3,5-triazine. Among these, 1,3-bis(β-epithiopropylthio)benzene, 1,4-bis(β-epithiopropylthio)benzene, 1,3,5-tris(β-epithiopropylthio)benzene, 1-alkylthio-3,5-bis(β-epothiopropylthio)benzene, 1-epoxyalkylthio-3,5-bis(β-epothiopropylthio)benzene, 1-thio-3,5-bis(β-epothiopropylthio)benzene, 1-halo-3,5-bis(β-epothiopropylthio)benzene, 1-hydroxy-3,5-bis(β-epothiopropylthio)benzene, 1-dialkylthiocarbamoyl-3,5-bis(β-epothiopropylthio)benzene, 1-alkylcarbamoylthio-3,5-bis(β-epothiopropylthio)benzene, 2-hydroxy-3,5-bis(β-epothiopropylthio)benzene, 1 ... ,5-bis(β-epithiopropylthio)-1,3,4-thiadiazole, 3,4-bis(β-epithiopropylthio)-1,2,5-thiadiazole, and 2,4,6-tris(β-epithiopropylthio)-1,3,5-triazine are preferred, 1,3-bis(β-epithiopropylthio)benzene, 1,4-bis(β-epithiopropylthio)benzene, 1,3,5-tris(β-epithiopropylthio)benzene, 2,5-bis(β-epithiopropylthio)-1,3,4-thiadiazole, and 2,4,6-tris(β-epithiopropylthio)-1,3,5-triazine are more preferred, and 1,3,5-tris(β-epithiopropylthio)benzene is even more preferred from the viewpoint of achieving a higher refractive index. The above-mentioned compound (a) may be used alone or in combination of two or more types.

[0033] The content of compound (a) is preferably 0.1 to 99.5% by mass, more preferably 5 to 95% by mass, even more preferably 10 to 95% by mass, and particularly preferably 10 to 85% by mass, relative to the total mass of the composition. When the content of compound (a) is within the above range, a sufficient color tone improving effect can be obtained. In one embodiment, from the viewpoint of improving color tone, the content of compound (a) is preferably 0.1 to 60% by mass, more preferably 1 to 55% by mass, and even more preferably 3 to 30% by mass, relative to the total mass of the composition.

[0034] [Polythiol (b)] Polythiol (b) refers to a compound having two or more thiol groups (-SH) per molecule. In this case, compounds corresponding to compound (a) (episulfide compounds having an aromatic skeleton) are not included in polythiol (b).

[0035] The polythiol (b) is not particularly limited, but from the viewpoint of a high color tone improving effect, 1,2,6,7-tetramercapto-4-thiaheptane, methanedithiol, (sulfanylmethyldisulfanyl)methanethiol, bis(2-mercaptoethyl)sulfide, 2,5-bis(mercaptomethyl)-1,4-dithiane, 1,2-bis(2-mercaptoethylthio)-3-mercaptopropane, 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, 1,1,3,3-tetrakis(mercaptomethylthio) )propane, tetramercaptopentaerythritol, 1,3-bis(mercaptomethyl)benzene, 1,4-bis(mercaptomethyl)benzene, and thiiranemethanethiol are preferred, bis(2-mercaptoethyl)sulfide, 1,2,6,7-tetramercapto-4-thiaheptane, methanedithiol, (sulfanylmethyldisulfanyl)methanethiol, and 4,8-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane are more preferred, and bis(2-mercaptoethyl)sulfide, 1,2,6,7-tetramercapto-4-thiaheptane, and 4,8-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane are even more preferred. The above-mentioned polythiols (b) may be used alone or in combination of two or more.

[0036] The content of polythiol (b) is preferably 0.1 to 30% by mass, more preferably 0.1 to 20% by mass, even more preferably 0.5 to 20% by mass, and particularly preferably 1 to 15% by mass, relative to the total mass of the composition. A content of polythiol (b) within the above range is preferred because it provides a good balance between color stabilization and heat resistance. In one embodiment, from the viewpoint of improving color, the content of compound (b) is preferably 2 to 30% by mass, more preferably 4 to 30% by mass, and even more preferably 7.5 to 25% by mass, relative to the total mass of the composition.

[0037] [Compound (c)] In one embodiment, the composition may further contain a compound (c). The compound (c) is represented by the following formula (2): Compound (c) is copolymerizable with compound (a), and when used together with compound (a), it has the effect of increasing curing reactivity.

[0038] [ka]

[0039] p represents an integer of 0 to 4, preferably 0 to 2, and more preferably 0 or 1.

[0040] q represents an integer of 0 to 2, preferably 0 to 2, and more preferably 0 or 1.

[0041] Specific examples of compound (c) include, but are not limited to, bis(β-epithiopropyl) sulfide and bis(β-epithiopropyl) disulfide. Of these, bis(β-epithiopropyl) sulfide is preferred. The above-mentioned compound (c) may be used alone or in combination of two or more. Note that bis(β-epithiopropyl) sulfide corresponds to the compound in the above formula (2) where p=q=0, and bis(β-epithiopropyl) disulfide corresponds to the compound in the above formula (2) where p=0 and q=1.

[0042] The content of compound (c) is 0 to 70 mass %, preferably 1 to 60 mass %, and more preferably 1 to 50 mass %, based on the total mass of the composition. When the content of compound (c) is within the above range, it is possible to improve the curing reactivity while ensuring heat resistance, which is preferable.

[0043] [sulfur] In one embodiment, the composition may further include sulfur, which can improve the refractive index of the resulting optical material.

[0044] The form of sulfur is not particularly limited and may be any form. Specific forms include finely divided sulfur, colloidal sulfur, precipitated sulfur, crystalline sulfur, and sublimed sulfur. Among these, finely divided sulfur is preferred from the viewpoint of dissolution rate.

[0045] The particle size (diameter) of sulfur is preferably smaller than 10 mesh (opening 1.70 mm), more preferably smaller than 30 mesh (opening 500 μm), and even more preferably smaller than 60 mesh (opening 250 μm). A particle size of sulfur smaller than 10 mesh is preferable because sulfur is easily dissolved.

[0046] The purity of sulfur is not particularly limited, but is preferably 98% or more, more preferably 99.0% or more, even more preferably 99.5% or more, and particularly preferably 99.9% or more. A sulfur purity of 98% or more is preferable because the color tone of the resulting optical material is further improved.

[0047] The sulfur content is preferably 0 to 20 mass %, more preferably 0.1 to 18 mass %, and even more preferably 1 to 15 mass %, relative to the total mass of the composition. A sulfur content within the above range is preferred because it provides an excellent balance between the refractive index improvement effect and solubility.

[0048] [Polymerizable compound] In one embodiment, the composition may further contain a polymerizable compound. By including the polymerizable compound, the physical properties of the optical material can be adjusted. Here, the "polymerizable compound" means a compound that can be copolymerized with compound (a).

[0049] The polymerizable compound is not particularly limited as long as it is a compound copolymerizable with compound (a), and examples thereof include episulfide compounds other than compound (a) and compound (c), vinyl compounds, methacrylic compounds, acrylic compounds, allyl compounds, etc. These compounds may be used alone or in combination of two or more.

[0050] The amount of the polymerizable compound added is not particularly limited as long as it is within a range that does not impair the effects of the present invention, and is, for example, preferably 0 to 30% by mass, more preferably 1 to 30% by mass, and even more preferably 1 to 20% by mass, relative to the total mass of the composition.

[0051] [Prepolymerization catalyst] In one embodiment, the composition may further include a prepolymerization catalyst. By including the prepolymerization catalyst, a precured product described below can be suitably produced.

[0052] The prepolymerization catalyst is not particularly limited, but examples thereof include imidazoles, phosphines, thioureas, quaternary ammonium salts, quaternary phosphonium salts, tertiary sulfonium salts, secondary iodonium salts, hindered amines, etc. Among these, imidazoles and hindered amines are preferred from the viewpoint of good compatibility with the composition.

[0053] The imidazoles are not particularly limited, but include N-benzylimidazole, 4-methylimidazole, 4-ethylimidazole, 1-phenylimidazole, 2-methyl-N-methylimidazole, and the like.

[0054] The hindered amine is not particularly limited, but examples thereof include 1,2,2,6,6-pentamethylpiperidyl methacrylate, 1,2,2,6,6-pentamethylpiperidyl acrylate, and 1,2,2,6,6-pentamethylpiperidyl-4-vinylbenzoate.

[0055] Among these, the prepolymerization catalyst preferably contains at least one selected from the group consisting of 2-mercapto-1-methylimidazole, 2-methyl-N-imidazole, and 1,2,2,6,6-pentamethylpiperidyl methacrylate. The above prepolymerization catalysts may be used alone or in combination of two or more.

[0056] The amount of prepolymerization catalyst added cannot be determined in general because it varies depending on the components of the composition, the mixing ratio, and the polymerization and curing method. However, it is usually preferably 0.0001% by mass to 10% by mass, and more preferably 0.003% by mass to 3.0% by mass, relative to 100% by mass of the total of compound (a), polythiol (b), compound (c), and sulfur. Prepolymerization catalysts added in an amount of 0.0001% by mass or more are preferred because the prepolymerization reaction proceeds smoothly. On the other hand, prepolymerization catalysts added in an amount of 10% by mass or less are preferred because they provide high oxidation resistance.

[0057] [Polymerization catalyst] In one embodiment, the composition may further include a polymerization catalyst, which allows the composition to be suitably polymerized to produce an optical material.

[0058] The polymerization catalyst is not particularly limited, but includes amines, phosphines, quaternary ammonium salts, quaternary phosphonium salts, tertiary sulfonium salts, secondary iodonium salts, mineral acids, Lewis acids, organic acids, silicic acids, tetrafluoroboric acids, peroxides, azo compounds, condensates of aldehydes and ammonia compounds, guanidines, thioureas, thiazoles, sulfenamides, thiurams, dithiocarbamates, xanthogenates, acidic phosphate esters, etc. Among these, amines, phosphines, quaternary ammonium salts, and quaternary phosphonium salts are preferred. These polymerization catalysts may be used alone or in combination of two or more.

[0059] The amount of the polymerization catalyst added is preferably 0.0001 to 10% by mass, more preferably 0.01 to 3% by mass, based on the total mass of the composition.

[0060] [Polymerization modifier] In one embodiment, the composition may further comprise a polymerization modifier.

[0061] The polymerization modifier is not particularly limited, but examples thereof include halides of elements of Groups 13 to 16 of the long-term periodic table. Among these, halides of silicon, germanium, tin, and antimony are preferred, and chlorides of germanium, tin, and antimony having an alkyl group are more preferred. These polymerization modifiers may be used alone or in combination of two or more.

[0062] The amount of the polymerization modifier added is preferably 0.0001 to 5.0% by mass, and more preferably 0.01 to 2% by mass, relative to the total mass of the composition.

[0063] [Additives] In one embodiment, the composition may further contain an additive. Examples of the additive include, but are not limited to, an antioxidant, a bluing agent, an ultraviolet absorber, a deodorizer, an adhesion improver, a release improver, and a radical polymerization initiator. These additives may be used alone or in combination of two or more.

[0064] The content of the additives is preferably 0 to 10% by mass, more preferably 0.5 to 10% by mass, relative to the total mass of the composition.

[0065] [Composition of the composition] In one embodiment, the composition has the following composition, i.e., the composition comprises, based on the total amount of the composition: Compound (a): 5 to 95 mass %, preferably 10 to 95 mass %; Polythiol (b): 0.1 to 30% by mass, preferably 0.5 to 20% by mass; Compound (c): 0 to 85% by mass, preferably 0 to 80% by mass; Sulfur: 0 to 20% by mass, preferably 0 to 15% by mass; Prepolymerization catalyst: 0 to 5% by mass, preferably 0 to 3% by mass; Polymerization catalyst: 0 to 5% by mass, preferably 0.0001 to 3% by mass; and Polymerization modifier: 0 to 5% by mass, preferably 0.0001 to 3% by mass; Includes.

[0066] <Method of producing the composition> The composition described above is not particularly limited and can be produced by a known method. Specifically, it can be produced by mixing the compound (a) and the polythiol (b), and, if necessary, the compound (c), sulfur, etc.

[0067] <Preliminary cured product> According to one aspect of the present invention, a pre-cured product is provided. The pre-cured product is obtained by pre-polymerizing the above-described composition. Forming a pre-cured product is preferable from the viewpoints of slowing the rate of viscosity increase, improving the transparency of the optical material, and facilitating handling. In this specification, the term "pre-cured product" refers to a liquid having a viscosity of 5,000 mps or less, and includes polymers, partial polymers, oligomers, etc. formed by a polymerization reaction of at least one of compound (a), polythiol (b), compound (c), sulfur, and polymerizable compounds. In this specification, the term "viscosity" refers to a value measured by the following method.

[0068] [Viscosity measurement method] The viscosity of the pre-cured product at 30°C is measured using a cone-plate viscometer DV2THA CP (manufactured by Brookfield AMETEK).

[0069] <Method of manufacturing pre-cured product> According to one aspect of the present invention, there is provided a method for producing a pre-cured product, the method including a pre-polymerization step of pre-polymerizing a composition.

[0070] [Prepolymerization process] The prepolymerization step is a step of prepolymerizing the composition.

[0071] The composition used is the one described above. The composition preferably contains a prepolymerization catalyst.

[0072] The prepolymerization step is preferably carried out by casting into a mold or the like, from the viewpoint of carrying out the polymerization step described below following the prepolymerization. In this case, it is preferable to remove impurities by filtration using a filter or the like having a pore size of about 0.1 to 5 μm before casting, from the viewpoint of improving the quality of the optical material.

[0073] The temperature of the prepolymerization is preferably from -10 to 160°C, more preferably from 0 to 100°C, and even more preferably from 20 to 80°C.

[0074] The prepolymerization time is preferably 0.1 to 480 minutes, more preferably 0.1 to 420 minutes, and even more preferably 0.1 to 360 minutes.

[0075] In one embodiment, the prepolymerization is preferably carried out at −10 to 160° C. for 0.1 to 480 minutes, more preferably at 0 to 100° C. for 0.1 to 420 minutes, and even more preferably at 20 to 80° C. for 0.1 to 360 minutes.

[0076] The prepolymerization may be carried out at normal pressure, under increased pressure, or under reduced pressure. When the prepolymerization is carried out under reduced pressure, hydrogen sulfide, which promotes the reaction, is removed, and therefore the reaction usually proceeds more gently than when carried out under normal pressure. When the prepolymerization is carried out under normal pressure, the prepolymerization may be carried out in the air or in an inert gas.

[0077] In the prepolymerization step, it is preferable to detect the progress of the prepolymerization reaction. Examples of the detection method include, but are not limited to, liquid chromatography, viscosity measurement, specific gravity measurement, and refractive index measurement. Among these, refractive index measurement is preferable because it is simple. These detection methods may be used alone or in combination of two or more.

[0078] The progress of the prepolymerization reaction is preferably detected inline. In particular, when the prepolymerization is performed under pressure or reduced pressure, inline detection is more preferable because it eliminates the need to release the pressure or reduced pressure to obtain a measurement sample. When performing inline detection, for example, when measuring the refractive index, the detection unit of the refractometer can be immersed in the composition before prepolymerization and the prepolymerization reaction solution to detect the increase in refractive index that accompanies the progress of the reaction, thereby enabling the progress of the reaction to be controlled. In addition, when using a detection method in which the measured value of the refractive index or the like changes with temperature, it is preferable to perform multiple regression analysis of the measurement temperature, refractive index, refractive index at a reference temperature, etc., to determine in advance the relationship between the temperature of the detection unit and the refractive index. Specifically, it is preferable to use a refractometer equipped with a temperature correction function that can automatically convert the measured value to the refractive index at the reference temperature. Examples of inline refractometers include a system in which a light-emitting diode is used as a light source and the angle of light reflected by a prism is identified by a CCD cell.

[0079] <Optical materials> According to one aspect of the present invention, there is provided an optical material. The optical material is obtained by curing the above-described composition or the above-described pre-cured product. That is, the optical material is a cured product of the above-described composition or pre-cured product.

[0080] The optical material according to this embodiment has a high refractive index and excellent color tone.

[0081] Specifically, the refractive index of the optical material is preferably 1.70 or higher, more preferably 1.72 or higher, even more preferably 1.73 or higher, and particularly preferably 1.75 or higher. That is, the refractive index of the optical material obtained from the above-mentioned composition is preferably 1.70 or higher, more preferably 1.72 or higher, even more preferably 1.73 or higher, and particularly preferably 1.75 or higher. The "refractive index" value is measured by the method described in the Examples.

[0082] Furthermore, the color tone of the optical material preferably has a YI value of 5 or less, more preferably 4 or less, even more preferably 3 or less, and particularly preferably 2 or less. That is, the YI value of the optical material obtained from the above-described composition is preferably 5 or less, more preferably 4 or less, even more preferably 3 or less, and particularly preferably 2 or less. In this specification, the "YI value" is measured by the method described in the examples.

[0083] The optical material according to this embodiment has a high refractive index and excellent color tone, and therefore it is possible to incorporate various comonomers into the composition and increase the amount of the comonomers incorporated, thereby enabling the design of optical materials with a wide range of physical properties.

[0084] <Method of manufacturing optical materials> According to one aspect of the present invention, there is provided a method for producing an optical material, the method including a polymerization step of polymerizing the above-described composition or the above-described pre-cured product.

[0085] [Polymerization process] The polymerization step is a step of polymerizing the above-mentioned composition or the above-mentioned pre-cured product.

[0086] The polymerization step is usually carried out by casting the composition or a pre-cured product into a mold or the like and polymerizing it. When using a composition, it is preferable to remove impurities by filtration using a filter with a pore size of about 0.1 to 5 μm before casting, from the viewpoint of improving the quality of the optical material.

[0087] In one embodiment, the polymerization step includes a step of increasing the temperature to a polymerization temperature, a step of maintaining the temperature at the polymerization temperature, and a step of decreasing the temperature.

[0088] The polymerization may be carried out in multiple stages. That is, the polymerization temperature may be maintained at two or more steps. In one embodiment, the polymerization step includes a step of increasing the temperature to a first polymerization temperature, a step of maintaining the temperature at the first polymerization temperature, a step of increasing the temperature to a second polymerization temperature, a step of maintaining the temperature at the second polymerization temperature, and a step of decreasing the temperature. In this case, the first polymerization temperature is lower than the second polymerization temperature. In another embodiment, the polymerization step includes a step of increasing the temperature to the first polymerization temperature, a step of maintaining the temperature at the first polymerization temperature, a step of decreasing the temperature to a second polymerization temperature, a step of maintaining the temperature at the second polymerization temperature, and a step of decreasing the temperature. In this case, the first polymerization temperature is higher than the second polymerization temperature.

[0089] The temperature increase rate in the temperature increase step is preferably 0.1°C to 100°C / h, and the temperature decrease rate in the temperature decrease step is preferably 0.1°C to 100°C / h.

[0090] The polymerization temperature is usually from -10 to 140°C, and preferably from 0 to 140°C.

[0091] The polymerization time is usually 1 to 100 hours, and preferably 1 to 72 hours. In this specification, the term "polymerization time" refers to the time including the time for the temperature increasing step and the temperature decreasing step.

[0092] After polymerization, the resulting optical material is preferably annealed. By performing the annealing treatment, distortion of the optical material can be prevented or suppressed. The annealing temperature is preferably 50 to 150°C. The annealing time is preferably 10 minutes to 5 hours.

[0093] The obtained optical material may be subjected to surface treatment such as dyeing, hard coating, impact-resistant coating, anti-reflection coating, anti-fogging coating, etc., as required.

[0094] <Applications of optical materials> The optical materials described above are useful for a variety of applications, including optical members, mechanical component materials, electrical and electronic component materials, automotive component materials, civil engineering and construction materials, and molding materials, as well as paints and adhesives. Among these, the optical materials are suitable for optical applications such as eyeglass lenses, (digital) camera imaging lenses, light beam focusing lenses, light diffusing lenses, and other lenses; LED encapsulants, optical adhesives, optical transmission bonding materials, optical fibers, prisms, filters, diffraction gratings, watch glasses, and transparent glass and cover glass for display devices; and display device applications such as substrates for display elements such as LCDs, organic EL displays, and PDPs, substrates for color filters, touch panel substrates, information recording substrates, display backlights, light guide plates, display protective films, anti-reflection films, anti-fogging films, and other coating agents (coating films). The optical materials are particularly preferably used for applications such as optical lenses, prisms, optical fibers, information recording substrates, and filters, and more preferably for optical lenses. That is, in one embodiment, an optical lens comprising the optical material described above is provided.

[0095] The optical lenses obtained from the composition according to the present invention are excellent in stability, hue, transparency, etc., and are therefore extremely useful in fields where expensive high refractive index glass lenses have traditionally been used, such as telescopes, binoculars, television projectors, etc. If necessary, they are preferably used in the form of aspherical lenses. [Example]

[0096] The present invention will be specifically explained below with reference to examples, but the embodiments can be modified as appropriate as long as the effects of the present invention are achieved.

[0097] The optical materials were analyzed and evaluated by the following methods.

[0098] [Refractive index of optical materials] The refractive index of the optical material at 25° C. for e-line (546.1 nm) was measured using a digital precision refractometer KPR-2000 (manufactured by Shimadzu Corporation).

[0099] [Color evaluation of optical materials] The YI value of the optical material having a thickness of 2.6 mm at 25° C. was measured using a spectrophotometer CM-5 (manufactured by Konica Minolta Japan, Inc.).

[0100] [Synthesis Example 1: Synthesis of 1,3,5-trimercaptobenzene (hereinafter referred to as TMB)] [ka]

[0101] It was synthesized with reference to Beilstein Journal of Organic Chemistry, 8, 461-471, No. 53; 2012. Specifically, the synthesis is as follows.

[0102] Specifically, a four-neck flask equipped with a thermometer and a dropping funnel was purged with nitrogen. Then, 400 g of N-methylpyrrolidone and 82.7 g (2067 mmol) of sodium hydroxide were added and stirred at 5°C. Subsequently, 186.4 g (2067 mmol) of t-butylthiol was added dropwise and stirred at 5°C for 3 hours. Furthermore, 50.0 g (275.56 mmol) of 1,3,5-trichlorobenzene was added, and the temperature was raised to 120°C and stirred for 24 hours. The reaction solution was then cooled to 25°C, 400 g of toluene was added, and the mixture was washed three times with 400 g of water. The solvent was then distilled off to obtain 45.3 g (132.3 mmol) of crude 1,3,5-tris(t-butylthio)benzene (TTBB).

[0103] The resulting crude TTBB (45.3 g, 132.3 mmol) was placed in a three-necked flask equipped with a thermometer, and the reaction vessel was purged with nitrogen. Then, 436 g of toluene was added and stirred at 20°C. Subsequently, 19.4 g (145.4 mmol) of aluminum chloride was added and stirred for 3 hours. 225 g of 20% sulfuric acid was added, and the toluene layer was washed with water three times. The solvent was then distilled off to obtain 16.1 g (92.4 mmol) of crude TMB.

[0104] The resulting crude TMB product was purified using a silica gel column to obtain a fraction containing TMB1 (TMB purity 100%) (TMB fraction 1) and two fractions containing TMB2 and TMB3 (TMB fractions 2 and 3). The results are shown in Table 1 below.

[0105] [Synthesis Example 2: Synthesis of TMB] [ka] The synthesis was carried out with reference to Bulletin de la Societe Chimique de France, (2), 302-8; 1987. Specifically, the synthesis is as follows.

[0106] Specifically, 30.0 g (238 mmol) of phloroglucinol and 375 g of N,N-dimethylformamide were added to a three-neck flask equipped with a thermometer. The reaction mixture was then cooled to 5°C, and 133.4 g (1189 mmol) of 1,4-diazabicyclo[2.2.2]octane and 147.0 g (1189 mmol) of dimethylthiocarbamoyl chloride were added and stirred for 24 hours. Next, 300 g of chloroform was added, followed by washing three times with 300 g of 10% aqueous NaOH solution. The solvent was then distilled off to yield 73.8 g (190 mmol) of crude 1,3,5-tris(dimethylthiocarbamoyl)benzene.

[0107] 73.8 g of the resulting crude 1,3,5-tris(dimethylthiocarbamoyl)benzene was placed in a three-necked flask equipped with a thermometer and stirred at 240°C for 7 hours. After that, the mixture was cooled to 25°C, yielding 73.8 g (190 mmol) of crude 1,3,5-tris(dimethylcarbamoylthio)benzene.

[0108] 73.8 g of the resulting crude 1,3,5-tris(dimethylcarbamoylthio)benzene was placed in a three-necked flask equipped with a thermometer. 826 g of diethylene glycol, 89.1 g of water, and 53.4 g (952 mmol) of potassium hydroxide were then added and stirred at 95°C for 10 hours. The mixture was then cooled to 25°C, and 370 g of 20% sulfuric acid and 740 g of chloroform were added. The organic layer was washed three times with water, and the solvent was distilled off to yield 15.9 g (91 mmol) of crude TMB.

[0109] The resulting crude TMB product was purified using a silica gel column to obtain a fraction containing TMB1 (TMB purity 100%) (TMB fraction 4) and three fractions containing TMB4, TMB5, and TMB6 (TMB fractions 5-7). The results are shown in Table 1 below.

[0110] [ka]

[0111] [Table 1]

[0112] [Synthesis Example 3: Synthesis of episulfide compounds] A four-neck flask equipped with a thermometer and a dropping funnel was charged with 15.0 g (86.1 mmol) of TMB fraction 1, and the reaction vessel was purged with nitrogen. Then, a solution of 0.72 g of 24% aqueous sodium hydroxide in 59.4 g of methanol and 65.0 g of toluene were added to the reaction vessel and stirred while cooling to 5°C. Next, 24.7 g (266.8 mmol) of epichlorohydrin was added dropwise while stirring, maintaining the liquid temperature at 5 to 15°C. After the dropwise addition, the mixture was stirred for an additional 3 hours at 5°C, yielding 1,3,5-tris(3-chloro-2-hydroxypropylthio)benzene.

[0113] Next, 64.6 g (387.3 mmol) of 24% aqueous sodium hydroxide solution was added dropwise while maintaining the liquid temperature at 5 to 15°C. After completion of the addition, the liquid temperature was brought to 15°C and aged for 17 hours. The organic layer was washed three times with 150 g of water, and the solvent was then distilled off to obtain 29.0 g of 1,3,5-tris(β-epoxypropylthio)benzene (total yield 98%).

[0114] To 29.0 g (84.7 mol) of the obtained 1,3,5-tris(β-epoxypropylthio)benzene, 145 mL of toluene, 145 mL of methanol, 1.56 g (15.2 mmol) of acetic anhydride, and 38.7 g (508.0 mmol) of thiourea were added, and the mixture was stirred for 24 hours at 20° C. 145 g of 20% sulfuric acid was added, and the toluene layer was washed three times with water. The solvent was then distilled off, yielding 23.1 g of crude 1,3,5-tris(β-epithiopropylthio)benzene (hereinafter referred to as Compound 1). The crude product was purified using a silica gel column to obtain a fraction (a-1) containing 100% pure compound 1 and two fractions (a-2 and a-3) containing compound 2 (1-mercapto-3,5-bis(β-epothiopropylthio)benzene) and compound 3 (1-(β-epoxypropylthio)-3,5-bis(β-epothiopropylthio)benzene). The results are shown in Table 2 below.

[0115] [Synthesis Example 4: Synthesis of episulfide compounds] A crude product of Compound 1 was obtained in the same manner as in Synthesis Example 3, except that TMB Fraction 2 was used instead of TMB Fraction 1. The crude product was purified using a silica gel column to obtain Fraction (a-1) containing Compound 1 with a purity of 100% and Fraction (a-4) containing Compound 4 (1-chloro-3,5-bis(β-epothiopropylthio)benzene). The results are shown in Table 2 below.

[0116] [Synthesis Example 5: Synthesis of episulfide compounds] A crude product of Compound 1 was obtained in the same manner as in Synthesis Example 3, except that TMB fraction 3 was used instead of TMB fraction 1. The crude product was purified using a silica gel column to obtain fraction (a-1) containing 100% pure Compound 1 and fraction (a-5) containing Compound 5 (1-t-butylthio-3,5-bis(β-epothiopropylthio)benzene). The results are shown in Table 2 below.

[0117] [Synthesis Example 6: Synthesis of episulfide compounds] A crude product of Compound 1 was obtained in the same manner as in Synthesis Example 3, except that TMB Fraction 5 was used instead of TMB Fraction 1. The crude product was purified using a silica gel column to obtain Fraction (a-1) containing Compound 1 with a purity of 100% and Fraction (a-6) containing Compound 6 (1-hydroxy-3,5-bis(β-epothiopropylthio)benzene). The results are shown in Table 2 below.

[0118] [Synthesis Example 7: Synthesis of episulfide compound] A crude product of Compound 1 was obtained in the same manner as in Synthesis Example 3, except that TMB fraction 6 was used instead of TMB fraction 1. The crude product was purified using a silica gel column to obtain fraction (a-1) containing 100% pure Compound 1 and fraction (a-7) containing Compound 7 (1-dimethylthiocarbamoyl-3,5-bis(β-epothiopropylthio)benzene). The results are shown in Table 2 below.

[0119] [Synthesis Example 8: Synthesis of episulfide compounds] A crude product of Compound 1 was obtained in the same manner as in Synthesis Example 3, except that TMB fraction 7 was used instead of TMB fraction 1. The crude product was purified using a silica gel column to obtain fraction (a-1) containing 100% pure Compound 1 and fraction (a-8) containing Compound 8 (1-dimethylcarbamoylthio-3,5-bis(β-epothiopropylthio)benzene). The results are shown in Table 2 below.

[0120] [Synthesis Example 9: Synthesis of episulfide compounds] A crude product of compound 9 (1,3-bis(β-epithiopropylthio)benzene) was obtained in the same manner as in Synthesis Example 3, except that 1,3-dimercaptobenzene (manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of TMB fraction 1. The crude product was purified using a silica gel column to obtain fraction (a-9) of compound 9 with a purity of 100%. The results are shown in Table 2 below.

[0121] [Synthesis Example 10: Synthesis of episulfide compounds] A crude product of compound 10 (2,5-bis(β-epithiopropylthio)-1,3,4-thiadiazole) was obtained in the same manner as in Synthesis Example 3, except that Bismuthiol (manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of TMB fraction 1. The crude product was purified using a silica gel column to obtain a fraction (a-10) of compound 10 with a purity of 100%. The results are shown in Table 2 below.

[0122] [Synthesis Example 11: Synthesis of episulfide compounds] A crude product of compound 11 (2,4,6-tris(β-epithiopropylthio)-1,3,5-triazine) was obtained in the same manner as in Synthesis Example 3, except that thiocyanuric acid (manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of TMB fraction 1. The crude product was purified using a silica gel column to obtain fraction (a-11) of compound 11 with a purity of 100%. The results are shown in Table 2 below.

[0123] Compound 1: 1,3,5-tris(β-epithiopropylthio)benzene Compound 2: 1-mercapto-3,5-bis(β-epothiopropylthio)benzene Compound 3: 1-(β-epoxypropylthio)-3,5-bis(β-epothiopropylthio)benzene Compound 4: 1-chloro-3,5-bis(β-epothiopropylthio)benzene Compound 5: 1-t-butylthio-3,5-bis(β-epothiopropylthio)benzene Compound 6: 1-Hydroxy-3,5-bis(β-epothiopropylthio)benzene Compound 7: 1-Dimethylthiocarbamoyl-3,5-bis(β-epothiopropylthio)benzene Compound 8: 1-Dimethylcarbamoylthio-3,5-bis(β-epothiopropylthio)benzene Compound 9: 1,3-bis(β-epithiopropylthio)benzene Compound 10: 2,5-bis(β-epithiopropylthio)-1,3,4-thiadiazole Compound 11: 2,4,6-tris(β-epithiopropylthio)-1,3,5-triazine

[0124] [ka]

[0125] [Table 2]

[0126] [Raw materials] As the polythiol (b), the following compounds b-1 to b-3 were prepared.

[0127] b-1: 1,2,6,7-tetramercapto-4-thiaheptane b-2: Bis(2-mercaptoethyl) sulfide b-3: 4,8-Dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane

[0128] [ka]

[0129] Furthermore, as compound (c), the following compounds c-1 to c-2 were prepared.

[0130] c-1: Bis(β-epithiopropyl) sulfide c-2: Bis(β-epithiopropyl) disulfide

[0131] [ka]

[0132] [Example 1] A composition was produced by mixing 80 parts by mass of fraction a-1, 20 parts by mass of compound b-1, 0.02 parts by mass of tetra-n-butylphosphonium bromide as a polymerization catalyst, and 0.05 parts by mass of di-n-butyltin dichloride as a polymerization regulator, while performing vacuum degassing.

[0133] [Examples 2 to 18, Comparative Examples 1 to 3] A composition was produced in the same manner as in Example 1, except that the composition was changed to that shown in Table 3.

[0134] [evaluation] The compositions produced in Examples 1 to 18 and Comparative Examples 1 to 3 were heated at 30°C for 10 hours, then heated to 100°C over 10 hours, and finally heated at 100°C for 5 hours to polymerize and harden. After allowing to cool, the compositions were annealed at 120°C for 30 minutes to produce optical materials.

[0135] The refractive index and color tone evaluation results of the produced optical materials are shown in Table 3 below.

[0136] [Table 3]

[0137] As is clear from the results in Table 3, the cured products (optical materials) obtained by curing the compositions of Examples 1 to 18 have a high refractive index and excellent color tone.

[0138] On the other hand, in Comparative Example 1, the polythiol (b) was not contained, and as a result, the color tone was insufficient.

[0139] Furthermore, it is clear that the refractive index of Comparative Example 2, which relates to the prior art and uses compound c-1 (bis(β-epithiopropyl) sulfide), is insufficient.

[0140] Furthermore, in Comparative Example 3, it is clear that when sulfur is added to increase the refractive index, the color tone is reduced.

Claims

1. The following formula (1): 【Chemistry 1】 [In the above formula, Ar represents an aromatic ring; m is 3, n represents an integer of 0 to 6; provided that m+n is equal to or less than the number of carbon atoms constituting the aromatic ring; R １ each independently represents an alkylthio group, an epoxyalkylthio group, a thiol group, a halogen group, a hydroxy group, a dialkylthiocarbamoyl group, or a dialkylcarbamoylthio group. A composition comprising a compound (a) represented by the formula: and a polythiol (b).

2. 2. The composition of claim 1, wherein Ar is an aromatic ring consisting of carbon and hydrogen.

3. 3. The composition according to claim 1, wherein m+n is 3 to 6.

4. The composition according to any one of claims 1 to 3, wherein the content of the compound (a) is 5 to 95 mass% based on the total mass of the composition.

5. The polythiol (b) is selected from the group consisting of 1,2,6,7-tetramercapto-4-thiaheptane, methanedithiol, (sulfanylmethyldisulfanyl)methanethiol, bis(2-mercaptoethyl)sulfide, 2,5-bis(mercaptomethyl)-1,4-dithiane, 1,2-bis(2-mercaptoethylthio)-3-mercaptopropane, 4,8-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 4,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundec ...7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 4,8-dimercaptomethyl-1,11-dimercap The composition according to any one of claims 1 to 4, comprising at least one selected from the group consisting of dimercapto-3,6,9-trithiaundecane, 5,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 1,1,3,3-tetrakis(mercaptomethylthio)propane, tetramercaptopentaerythritol, 1,3-bis(mercaptomethyl)benzene, 1,4-bis(mercaptomethyl)benzene, and thiiranemethanethiol.

6. The following formula (2): 【Chemistry 2】 [In the above formula, p represents an integer of 0 to 4; and q represents an integer of 0 to 2. The composition according to any one of claims 1 to 5, further comprising a compound (c) represented by:

7. The composition of any one of claims 1 to 6, further comprising sulfur.

8. The composition of any one of claims 1 to 7, further comprising a prepolymerization catalyst.

9. 9. The composition of claim 8, wherein the prepolymerization catalyst comprises at least one selected from the group consisting of 2-mercapto-1-methylimidazole, 2-methyl-N-imidazole, and 1,2,2,6,6-pentamethylpiperidyl methacrylate.

10. A pre-cured product obtained by pre-polymerizing the composition according to any one of claims 1 to 9.

11. An optical material obtained by curing the composition according to any one of claims 1 to 9 or the pre-cured product according to claim 10.

12. An optical lens comprising the optical material of claim 11.

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