Photocurable episulfide composition, cured product, laminate, and method for producing cured product

Abstract

Provided is a photocurable episulfide composition containing a photobase generator (a) and an episulfide compound (b), wherein the photobase generator (a) is a compound represented by formula (1) or formula (2). R is a substituent, X+ is a cation, A1 and A2 are 5- to 8-membered ring structures, and L and R1 to R4 are substituents.

Description

Photocurable episulfide composition, cured product, laminate, and method for producing the cured product

[0001] This disclosure relates to a photocurable episulfide composition, a cured product, a laminate, and a method for producing a cured product.

[0002] Plastic lenses 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. Among resin-based optical materials, such as plastic lenses, optical materials obtained by polymerizing episulfide compounds as monomers are known to have a high refractive index (see, for example, Patent Document 1 below). In addition, a photocurable composition containing an episulfide compound is known, which contains an episulfide compound and a photobase generator (see, for example, Patent Document 2 below).

[0003] Patent Document 1: Japanese Unexamined Patent Publication No. 2002-194083 Patent Document 2: International Publication No. 2014 / 208656

[0004] Episulfide compounds do not transmit light with wavelengths less than 330 nm well. Therefore, in order to cure (i.e., photopolymerize) a photocurable composition containing a photobase generator and an episulfide compound (hereinafter also referred to as "photocurable episulfide composition") in a short time, it is desirable to use a photobase generator that reacts to light with wavelengths of 330 nm or higher. Furthermore, some types of photobase generators have poor solubility in episulfide compounds (i.e., poor compatibility with episulfide compounds). Therefore, it is desirable to use a photobase generator with excellent solubility in episulfide compounds (i.e., good compatibility with episulfide compounds) as the photobase generator in a photocurable episulfide composition.

[0005] This disclosure has been made in view of the above circumstances. An object of one aspect of this disclosure is to provide a photocurable episulfide composition containing a photobase generator (a) and an episulfide compound (b), wherein the photobase generator (a) has excellent solubility in the episulfide compound (b) and the episulfide compound (b) has excellent photopolymerization properties, as well as a cured product, a laminate, and a method for producing a cured product using this photocurable episulfide composition.

[0006] The means for solving the above problems include the following embodiments: <1> A photocurable episulfide composition comprising a photobase generator (a) and an episulfide compound (b), wherein the photobase generator (a) is a compound represented by the following formula (1) or the following formula (2).

[0007]

[0008] In formula (1), R represents an aromatic hydrocarbon group which is a phenyl group, naphthyl group, anthracenyl group, or phenanthuryl group, or an unsaturated heterocyclic group which is a pyrrolyl group, furfuryl group, imidazolyl group, pyrazolyl group, oxazolyl group, thiazolyl group, triazolyl group, tetrazolyl group, pyridinium group, triazinyl group, or tetrazinyl group, and the aromatic hydrocarbon group and the unsaturated heterocyclic group may each be substituted with a halogen atom, alkyl group, alkoxy group, alkylthio group, aryl group, alkenyl group, cycloalkyl group, or heterocyclic group, or may be fused with a heterocyclic ring, X ＋ A represents a cation having an ammonium structure, an amidinium structure, a guanidinium structure, or a bigamidium structure. In formula (2), A １ and A ２ Each independently represents a 5-8 membered ring structure, L represents a phenyl group, a naphthyl group, anthracenyl group, or phenanthryl group, and each of the phenyl group, naphthyl group, anthracenyl group, and phenanthryl group may be substituted with a halogen atom, an aliphatic hydrocarbon group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a cyano group, and a heterocyclic group, or may be fused with a heterocyclic ring, R １ ~R４ Each of these independently represents a C1-C8 alkyl group, a phenyl group, a naphthyl group, an anthracenyl group, or a phenanthrill group, and the phenyl group, naphthyl group, anthracenyl group, and phenanthrill group may be substituted with a halogen atom, an alkyl group, an aryl group, an alkenyl group, a cycloalkyl group, or a heterocyclic group, or may be fused with a heterocyclic group.

[0009] <2> The photocurable episulfide composition according to <1>, wherein the absolute value of the difference in Hansen solubility parameters between the photobase generator (a) and the episulfide compound (b) is 3.0 or less. <3> The molar extinction coefficient at 365 nm of a 0.5 mg / mL acetonitrile solution of the photobase generator (a) is 50 L·mol. －１ ・cm －１The photocurable episulfide composition according to <1> or <2>. <4> The photocurable episulfide composition according to any one of <1> to <3>, wherein the episulfide compound (b) comprises a compound comprising an episulfide ring and at least one of a sulfide bond and a disulfide bond. <5> The photocurable episulfide composition according to any one of <1> to <4>, wherein the content of the photobase generator (a) relative to the total amount of the episulfide compound (b) is 0.1% to 2% by mass. <6> The photocurable episulfide composition according to any one of <1> to <5> further contains a polythiol compound. <7> The aforementioned polythiol compounds include 5,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 4,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 4,8-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 4-mercaptomethyl-1,8-dimercapto-3,6-dithiaoctane, pentaerythritol tetrakis(3-mercaptopropionate), pentaerythritol tetrakis(2-mercaptoacetate), and 2,5-bis(mercaptomethyl). A photocurable episulfide composition according to <6>, comprising at least one selected from the group consisting of -1,4-dithiane, bis(2-mercaptoethyl)sulfide, 1,1,3,3-tetrakis(mercaptomethylthio)propane, 4,6-bis(mercaptomethylthio)-1,3-dithiane, 2-(2,2-bis(mercaptomethylthio)ethyl)-1,3-dithiethane, 1,1,2,2-tetrakis(mercaptomethylthio)ethane, 3-mercaptomethyl-1,5-dimercapto-2,4-dithiapentane, and tris(mercaptomethylthio)methane. <8> A photocurable episulfide composition according to any one of <1> to <7>, further comprising a polyiso(thio)cyanate compound.<9> The photocurable episulfide composition according to <8>, wherein the polyisothiocyanate compound contains at least one selected from the group consisting of pentamethylene diisocyanate, hexamethylene diisocyanate, xylylene diisocyanate, isophorone diisocyanate, bis(isocyanatomethyl)cyclohexane, bis(isocyanatocyclohexyl)methane, 2,5-bis(isocyanatomethyl)bicyclo-[2.2.1]-heptane, 2,6-bis(isocyanatomethyl)bicyclo-[2.2.1]-heptane, tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, and phenylene diisocyanate. <10> A photocurable episulfide composition containing a photo-base generator (a) and an episulfide compound (b), wherein the absolute value of the difference in Hansen solubility parameters between the photo-base generator (a) and the episulfide compound (b) is 3.0 or less, and the molar absorption coefficient of a 0.5 mg / mL acetonitrile solution of the photo-base generator (a) at 365 nm is 50 L·mol. －１ ·cm －１ or more. <11> The photocurable episulfide composition according to <10>, wherein the photo-base generator (a) is a compound containing a cationic species having a structure containing a nitrogen cation and an anionic species. <12> The photocurable episulfide composition according to <10> or <11>, wherein the photo-base generator (a) is a compound represented by the following formula (1) or the following formula (2).

[0010]

[0011] In formula (1), R represents an aromatic hydrocarbon group which is a phenyl group, a naphthyl group, an anthracenyl group, or a phenanthryl group, or an unsaturated heterocyclic group which is a pyrrolyl group, a furfuryl group, an imidazolyl group, a pyrazolyl group, an oxazolyl group, a thiazolyl group, a triazolyl group, a tetrazolyl group, a pyridinium group, a triazinyl group, or a tetrazinyl group. The aromatic hydrocarbon group and the unsaturated heterocyclic group may each be substituted by a halogen atom, an alkyl group, an alkoxy group, an alkylthio group, an aryl group, an alkenyl group, a cycloalkyl group, or a heterocyclic group, or may be condensed with a heterocyclic ring. X＋ A represents a cation having an ammonium structure, an amidinium structure, a guanidinium structure, or a bigamidium structure. In formula (2), A １ and A ２ Each independently represents a 5-8 membered ring structure, L represents a phenyl group, a naphthyl group, anthracenyl group, or phenanthryl group, and each of the phenyl group, naphthyl group, anthracenyl group, and phenanthryl group may be substituted with a halogen atom, an aliphatic hydrocarbon group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a cyano group, and a heterocyclic group, or may be fused with a heterocyclic ring, R １ ~R ４ Each of these independently represents a C1-C8 alkyl group, a phenyl group, a naphthyl group, an anthracenyl group, or a phenanthrill group, and the phenyl group, naphthyl group, anthracenyl group, and phenanthrill group may be substituted with a halogen atom, an alkyl group, an aryl group, an alkenyl group, a cycloalkyl group, or a heterocyclic group, or may be fused with a heterocyclic group.

[0012] <13> A photocurable episulfide composition according to any one of <10> to <12>, wherein the episulfide compound (b) is bis(2,3-epithiopropyl)sulfide or bis(2,3-epithiopropyl)disulfide. <14> A cured product of the photocurable episulfide composition according to any one of <1> to <13>. <15> The cured product according to <14> is an optical waveguide. <16> A laminate comprising the cured product according to <14> or <15> and a substrate. <17> A method for producing a cured product, comprising irradiating the photocurable episulfide composition according to any one of <1> to <13> with ultraviolet light or visible light to obtain a cured product of the photocurable episulfide composition. <18> A method for producing a cured product according to <17>, comprising: injecting the photocurable episulfide composition between a pair of resin molds; and irradiating the photocurable episulfide composition injected between the pair of resin molds with ultraviolet light or visible light to obtain a cured product of the photocurable episulfide composition.

[0013] According to one aspect of the present disclosure, a photocurable episulfide composition is provided, comprising a photobase generator (a) and an episulfide compound (b), wherein the photobase generator (a) exhibits excellent solubility in the episulfide compound (b), and the episulfide compound (b) exhibits excellent photopolymerization properties. Furthermore, a cured product, a laminate, and a method for producing a cured product using this photocurable episulfide composition are also provided.

[0014] In this disclosure, numerical ranges expressed using "~" mean a range that includes the numbers before and after "~" as the lower and upper limits. In this disclosure, the amount of each component in a composition means the total amount of multiple substances present in the composition, unless otherwise specified, if there are multiple substances corresponding to each component in the composition. In numerical ranges described in steps in this disclosure, the upper or lower limit stated in one numerical range may be replaced with the upper or lower limit of another numerical range described in steps. Also, in numerical ranges described in this disclosure, the upper or lower limit of that numerical range may be replaced with the values ​​shown in the examples. In this disclosure, "light" means ultraviolet light or visible light.

[0015] The first and second embodiments of this disclosure will be described below. There may be overlapping portions between the first and second embodiments. For example, the photocurable episulfide composition of the first embodiment may have the characteristics of the photocurable episulfide composition of the second embodiment.

[0016] ≪First Embodiment≫

[0017] [Photocurable Episulfide Composition] The first embodiment of the photocurable episulfide composition of the present disclosure is a photocurable episulfide composition containing a photobase generator (a) and an episulfide compound (b), wherein the photobase generator (a) is a compound represented by the following formula (1) or the following formula (2).

[0018]

[0019] The signs in equations (1) and (2) (i.e., R, X) ＋ A １ A ２ , L, and R １ ~R ４ The meaning of ) will be explained later.

[0020] The photocurable episulfide composition of the first embodiment exhibits excellent solubility of the photobase generator (a) in the episulfide compound (b) (i.e., compatibility between the photobase generator (a) and the episulfide compound (b)) and excellent photopolymerizability of the episulfide compound (b) (i.e., photocurability of the photocurable episulfide composition). These effects are obtained by the photobase generator (a), which is a compound represented by formula (1) or formula (2).

[0021] <Photobase Generator (a)> The photocurable episulfide composition of the first embodiment contains at least one photobase generator (a). Here, the photobase generator (a) is a compound represented by the following formula (1) or formula (2).

[0022] (Compounds represented by formula (1)) The compounds represented by formula (1) are as follows:

[0023]

[0024] In formula (1), R represents an aromatic hydrocarbon group which is a phenyl group, naphthyl group, anthracenyl group, or phenanthuryl group, or an unsaturated heterocyclic group which is a pyrrolyl group, furfuryl group, imidazolyl group, pyrazolyl group, oxazolyl group, thiazolyl group, triazolyl group, tetrazolyl group, pyridinium group, triazinyl group, or tetrazinyl group, and the aromatic hydrocarbon group and the unsaturated heterocyclic group may each be substituted with a halogen atom, alkyl group, alkoxy group, alkylthio group, aryl group, alkenyl group, cycloalkyl group, or heterocyclic group, or may be fused with a heterocyclic ring, X ＋ This represents a cation having an ammonium structure, an amidinium structure, a guanidinium structure, or a biguamidium structure.

[0025] In R, a heterocyclic group with 5 to 8 members is preferred as the substituent. In R, a heterocyclic group with 5 to 8 members is preferred as the heterocyclic group which may be fused with the aromatic hydrocarbon group and the unsaturated heterocyclic group.

[0026] R is preferably a phenyl group, naphthyl group, anthracenyl group, or phenanthryl group, which may be substituted with an alkoxy group or an alkylthio group, and may be fused with a 5-8 membered heterocycle.

[0027] A preferred example of R in formula (1) is shown below. In this disclosure, * in the chemical formulas indicates a bond position.

[0028]

[0029] In formula (1), X ＋ This represents a cation having an ammonium structure, an amidinium structure, a guanidinium structure, or a biguamidium structure.

[0030] X in equation (1) ＋ As such, cations represented by formulas (X1) to (X4) are preferred. Also, the cation in formula (2) described later is also the same as the X in formula (1). ＋ This can be cited as a favorable example.

[0031]

[0032] In formula (X1), R １ ~R ４ Each of these independently represents an alkyl group having 1 to 8 carbon atoms, R ５ ~R ８ Each of these independently represents a C1-C8 alkyl group, a phenyl group, a naphthyl group, an anthracenyl group, or a phenanthrill group, and the phenyl group, naphthyl group, anthracenyl group, and phenanthrill group may be substituted with a halogen atom, an alkyl group, an aryl group, an alkenyl group, a cycloalkyl group, or a heterocyclic group.

[0033] In formula (X1), R １ ~R ４ It is preferable that they are the same. １ ~R ４ It is preferably an alkyl group having 2 to 5 carbon atoms, more preferably a linear alkyl group, and even more preferably an n-butyl group.

[0034] In formula (X2), R １ ~R ７Each of these independently represents an alkyl group having 1 to 8 carbon atoms or a cycloalkyl group having 3 to 8 carbon atoms.

[0035] In formula (X2), R ４ and R ５ It is preferably a cycloalkyl group having 3 to 8 carbon atoms, and more preferably a cycloalkyl group having 4 to 7 carbon atoms. The cycloalkyl group is preferably a cyclohexyl group. １ ~R ３ , R ６ , and R ７ It is preferably an alkyl group having 1 to 8 carbon atoms, more preferably an alkyl group having 1 to 5 carbon atoms, and even more preferably a methyl group. １ ~R ３ , R ６ , and R ７ It is preferable that it be a linear alkyl group.

[0036] In formula (X3), n represents an integer from 1 to 3. It is preferable that n is 1 or 3.

[0037] Specific examples of the compound represented by formula (1) as the photobase generator (a) include photobases 1 to 7 in the examples described later. However, the compound represented by formula (1) is not limited to these specific examples.

[0038] (Compound represented by formula (2)) The compound represented by formula (2) is as follows. When the photobase generator (a) contained in the photocurable episulfide composition of the first embodiment contains the compound represented by formula (2), the pot life of the photocurable episulfide composition is further improved.

[0039]

[0040] In formula (2), A １ and A ２Each independently represents a 5-8 membered ring structure, L represents a phenyl group, a naphthyl group, anthracenyl group, or phenanthryl group, and each of the phenyl group, naphthyl group, anthracenyl group, and phenanthryl group may be substituted with a halogen atom, an aliphatic hydrocarbon group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a cyano group, and a heterocyclic group, or may be fused with a heterocyclic ring, R １ ~R ４ Each of these independently represents a C1-C8 alkyl group, a phenyl group, a naphthyl group, an anthracenyl group, or a phenanthrill group, and the phenyl group, naphthyl group, anthracenyl group, and phenanthrill group may be substituted with a halogen atom, an alkyl group, an aryl group, an alkenyl group, a cycloalkyl group, or a heterocyclic group.

[0041] The preferred embodiments and specific examples of L in formula (2) are the same as the preferred embodiments and specific examples of R in formula (1).

[0042] A in equation (2) １ It is preferable that it has a five-membered ring structure. ２ It is preferable that it has a six-membered ring structure.

[0043] The following cations are preferred as cations in the compound represented by formula (2).

[0044]

[0045] In formula (2), R １ ~R ４ Each of these is preferably independently a phenyl group or an alkyl group having 1 to 8 carbon atoms (more preferably 2 to 6, even more preferably 4).

[0046] The following anions are preferred as anions in the compound represented by formula (2).

[0047]

[0048] A specific example of the compound represented by formula (2) as a photobase generator (a) is photobase 8 in the examples described later. However, the compound represented by formula (1) is not limited to this specific example.

[0049] The content of the photobase generator (a) is preferably 0.01% to 5.0% by mass, more preferably 0.05% to 3.0% by mass, and even more preferably 0.1% to 2.0% by mass, relative to the total amount of the episulfide compound (b).

[0050] <Episulfide compound (b)> The photocurable episulfide composition of the first embodiment contains at least one episulfide compound (b).

[0051] The episulfide compound (b) preferably includes a compound comprising an episulfide ring and at least one of a sulfide bond and a disulfide bond.

[0052] Examples of compounds containing an episulfide ring and at least one of a sulfide bond and a disulfide bond include episulfide compounds represented by the following formula (5).

[0053]

[0054] In formula (5), X represents a sulfur atom (S) or an oxygen atom (O), Y represents a straight-chain divalent hydrocarbon group having 1 to 4 carbon atoms, a branched divalent hydrocarbon group having 2 to 4 carbon atoms, a cyclic divalent hydrocarbon group having 3 to 6 carbon atoms, a 1,4-dithiane group, an arylene group, or an aralkylene group, m represents an integer from 0 to 2, and n represents an integer from 0 to 3. Y may contain substituents or may be unsubstituted.

[0055] Y preferably represents a linear divalent hydrocarbon group having 1 to 4 carbon atoms, a branched divalent hydrocarbon group having 2 to 4 carbon atoms, or a cyclic divalent hydrocarbon group having 3 to 6 carbon atoms, and more preferably a linear divalent hydrocarbon group having 1 to 4 carbon atoms. m preferably represents 0 or 1, and more preferably 0. n preferably represents 0 or 1, and more preferably 1.

[0056] The episulfide compound preferably contains at least one selected from the group consisting of bis(2,3-epithiopropyl)sulfide, bis(2,3-epithiopropyl)disulfide, and 2,5-bis(2,3-epithiopropylthiomethyl)-1,4-dithiane, and preferably contains at least one of bis(2,3-epithiopropyl)sulfide and bis(2,3-epithiopropyl)disulfide, and particularly preferably contains bis(2,3-epithiopropyl)disulfide.

[0057] The photocurable episulfide composition of the first embodiment may contain, as episulfide compound (b), either a compound in formula (5) where X is a sulfur atom or a compound in formula (5) where X is an oxygen atom, or both.

[0058] The content of episulfide compound (b) is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 80% by mass or more, based on the total amount of the photocurable episulfide composition.

[0059] <Absolute value of the difference in Hansen solubility parameters between the photobase generator (a) and the episulfide compound (b)> As described above, the photocurable episulfide composition of the first embodiment has excellent solubility of the photobase generator (a) in the episulfide compound (b) (i.e., compatibility between the photobase generator (a) and the episulfide compound (b)). Related to this effect, the absolute value of the difference in Hansen solubility parameters between the photobase generator (a) and the episulfide compound (b) (hereinafter, "|Δδ") Ｔ | (also called |) is preferably 3.0 or less. |△δ Ｔ When | is 3.0 or less, the solubility of the photobase generator (a) in the episulfide compound (b) is superior. |△δ Ｔ | is more preferably 2.0 or less, and even more preferably 1.0 or less. |△δ Ｔ The | symbol can be zero or greater than zero.

[0060] In this disclosure, the Hansen solubility parameter (δ Ｔ) is the Hansen solubility parameter (δ) specified in J. Mater. Chem. A, 2020, 8, 22657. Ｔ (Units are in MPa) １／２ ) means.

[0061] In this disclosure, |△δ Ｔ | (i.e., the Hansen solubility parameter (δ) between the photobase generator (a) and the episulfide compound (b) Ｔ The absolute value of the difference between (a) is calculated as follows. First, the δ of the photobase generator (a) Ｔ δ Ｔ (a), and the δ of the episulfide compound (b) Ｔ δ Ｔ (b) is determined by the method shown in the examples described below. Based on the obtained values, |Δδ is calculated using the following formula. Ｔ We find |. |△δ Ｔ |=|δ Ｔ (b) - δ Ｔ (a) |

[0062] <Molar extinction coefficient of acetonitrile solution of photobase generator (a)> The photocurable episulfide composition of the first embodiment described above exhibits excellent photopolymerization properties of episulfide compound (b). In relation to this effect, the photocurable episulfide composition of the first embodiment has a molar extinction coefficient at 365 nm of a 0.5 mg / mL acetonitrile solution of photobase generator (a), preferably 50 L·mol －１ ・cm －１ That is all. The above molar extinction coefficient is 50 L·mol. －１ ・cm －１ In the above cases, the photopolymerization properties of episulfide compound (b) are superior.

[0063] Here, the molar extinction coefficient is a value measured using a UV-Vis spectrophotometer with a measurement optical path length of 1 cm. For example, a UV-1800 (manufactured by Shimadzu Corporation) is used as the UV-Vis spectrophotometer.

[0064] <Polythiol Compounds> The photocurable episulfide composition of the first embodiment may contain at least one polythiol compound. In the first embodiment, a polythiol compound means a compound having two or more thiol groups in one molecule.

[0065] Specific examples of polythiol compounds include those exemplified in International Publication No. 2016 / 125736.

[0066] The polythiol compounds are 5,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 4,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 4,8-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 4-mercaptomethyl-1,8-dimercapto-3,6-dithiaoctane, pentaerythritol tetrakis(3-mercaptopropionate), pentaerythritol tetrakis(2-mercaptoacetate), and 2,5-bis(mercaptomethyl Preferably, it contains at least one selected from the group consisting of )-1,4-dithiane, bis(2-mercaptoethyl)sulfide, 1,1,3,3-tetrakis(mercaptomethylthio)propane, 4,6-bis(mercaptomethylthio)-1,3-dithiane, 2-(2,2-bis(mercaptomethylthio)ethyl)-1,3-dithiethane, 1,1,2,2-tetrakis(mercaptomethylthio)ethane, 3-mercaptomethyl-1,5-dimercapto-2,4-dithiapentane, and tris(mercaptomethylthio)methane. It is more preferable to include at least one selected from the group consisting of 4-mercaptomethyl-1,8-dimercapto-3,6-dithiaoctane, 5,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 4,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 4,8-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, pentaerythritol tetrakiss (3-mercaptopropionate), and pentaerythritol tetrakiss (2-mercaptoacetate). It is even more preferable to include at least one selected from the group consisting of 4-mercaptomethyl-1,8-dimercapto-3,6-dithiaoctane, 5,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 4,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, and 4,8-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane.

[0067] When the photocurable episulfide composition of the first embodiment contains a polythiol compound, the content of the polythiol compound is preferably 50% by mass or less, more preferably 1% to 30% by mass, and even more preferably 2% to 20% by mass, based on the total amount of episulfide compound (b).

[0068] <Polyiso(thio)cyanate compounds> The photocurable episulfide composition of the first embodiment may contain at least one polyiso(thio)cyanate compound. In the first embodiment, a polyiso(thio)cyanate compound means a compound having two or more isocyanate groups or isothiocyanate groups in one molecule.

[0069] The polyiso(thio)cyanate compounds may include dimers, trimers, or prepolymers. Examples of these polyiso(thio)cyanate compounds are those exemplified in International Publication No. 2011 / 055540.

[0070] Examples of polyiso(thio)cyanate compounds include aliphatic polyiso(thio)cyanate compounds, alicyclic polyiso(thio)cyanate compounds, aromatic polyiso(thio)cyanate compounds, and heterocyclic polyiso(thio)cyanate compounds.

[0071] Alicyclic polyiso(thio)cyanate compounds refer to polyiso(thio)cyanate compounds that contain an alicyclic structure and may also contain a heterocyclic structure. Aromatic polyiso(thio)cyanate compounds refer to polyiso(thio)cyanate compounds that contain an aromatic structure and may also contain an alicyclic structure and a heterocyclic structure. Heterocyclic polyiso(thio)cyanate compounds refer to polyiso(thio)cyanate compounds that contain a heterocyclic structure and do not contain an alicyclic structure or an aromatic structure.

[0072] The polyiso(thio)cyanate compound preferably includes at least one selected from the group consisting of aliphatic polyiso(thio)cyanate compounds, alicyclic polyiso(thio)cyanate compounds, aromatic polyiso(thio)cyanate compounds, and heterocyclic polyiso(thio)cyanate compounds.

[0073] The polyiso(thio)cyanate compound preferably contains at least one selected from the group consisting of pentamethylene diisocyanate, hexamethylene diisocyanate, xylylene diisocyanate, isophorone diisocyanate, bis(isocyanatomethyl)cyclohexane, bis(isocyanatocyclohexyl)methane, 2,5-bis(isocyanatomethyl)bicyclo-[2.2.1]-heptane, 2,6-bis(isocyanatomethyl)bicyclo-[2.2.1]-heptane, tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, and phenylene diisocyanate. It is more preferable to include at least one selected from the group consisting of 2,5-bis(isocyanatomethyl)bicyclo-[2.2.1]-heptane, 2,6-bis(isocyanatomethyl)bicyclo-[2.2.1]-heptane, xylylene diisocyanate, and 1,3-bis(isocyanatomethyl)cyclohexane, and even more preferable to include at least one selected from the group consisting of 2,5-bis(isocyanatomethyl)bicyclo-[2.2.1]-heptane, 2,6-bis(isocyanatomethyl)bicyclo-[2.2.1]-heptane, and m-xylylene diisocyanate.

[0074] When the photocurable episulfide composition of the first embodiment contains a polyiso(thio)cyanate compound, the content of the polyiso(thio)cyanate compound is preferably 50% by mass or less, more preferably 1% to 30% by mass, and even more preferably 2% to 20% by mass, based on the total amount of episulfide compound (b).

[0075] <Stabilizer (S)> The photocurable episulfide composition of the first embodiment may contain at least one stabilizer (S). Preferred examples of stabilizer (S) include acids with a pKa of less than 2.0 and anhydrides of acids with a pKa of less than 2.0. The composition may contain only one stabilizer (S) or two or more.

[0076] Examples of acids with a pKa of less than 2.0 include hydrochloric acid (pKa: -3.7), sulfuric acid (pKa: -3.0), nitric acid (pKa: -1.4), and sulfonic acid with a pKa of less than 2.0. From the viewpoint of the pot life of the composition, sulfonic acid with a pKa of less than 2.0 is preferred. Examples of sulfonic acid with a pKa of less than 2.0 include 10-camphor sulfonic acid (pKa: 1.2), methanesulfonic acid (pKa: -2.6), p-toluenesulfonic acid (pKa: -2.8), vinylsulfonic acid (pKa: -2.7), and benzenesulfonic acid (pKa: 0.7). Acids with a pKa of less than 2.0 may form hydrates. The pKa of an acid with a pKa of less than 2.0 may be 0.2 or higher, 0.5 or higher, or 1.0 or higher.

[0077] Examples of acid anhydrides with a pKa of less than 2.0 include the acid anhydrides mentioned above. From the viewpoint of the pot life of the composition, sulfonic acid anhydrides with a pKa of less than 2.0 are preferred.

[0078] The content of stabilizer (S) is preferably 0.001 parts by mass or more, more preferably 0.005 parts by mass or more, and even more preferably 0.01 parts by mass or more, when the total amount of the photocurable episulfide composition is 100 parts by mass or less. The content of stabilizer (S) is preferably 1.0 part by mass or less, more preferably 0.5 parts by mass or less, and even more preferably 0.3 parts by mass or less, when the total amount of the photocurable episulfide composition is 100 parts by mass or less.

[0079] <Polyether-Modified Silicone Compound> The photocurable episulfide composition of the first embodiment may contain a polyether-modified silicone compound. Including a polyether-modified silicone compound in the photocurable episulfide composition of the first embodiment improves the release properties of the cured product.

[0080] From the viewpoint of release properties, the polyether-modified silicone compound preferably contains at least one selected from the group consisting of a polyether-modified silicone compound (d1) represented by the following formula (d1) and a polyether-modified silicone compound (d2) represented by the following formula (d2).

[0081]

[0082] In equation (d1), m and n each independently represent an integer greater than or equal to 1. a and b each independently represent an integer greater than or equal to 0 (except when both a and b are 0). １ represents a linear or branched alkyl group having 1 to 6 carbon atoms, a linear or branched alkenyl group having 2 to 10 carbon atoms, an acryloyl group, a methacryloyl group, or a hydrogen atom. In formula (d2), p represents an integer of 1 or more, and c, d, e, and f each independently represent an integer of 0 or more (except when c, d, e, and f are all 0). R ２ and R ３ Each of these independently represents a linear or branched alkyl group having 1 to 6 carbon atoms, a linear or branched alkenyl group having 2 to 10 carbon atoms, an acryloyl group, a methacryloyl group, or a hydrogen atom.

[0083] In formulas (d1) and (d2), (OC ３ H ６ The unit represented by ) is the oxypropylene group (O-CH(CH ３ ) - CH ２ ) represents Si-C ３ H ６ - (OC ２ H ４ C in the area represented by ) ３ H ６ is a trimethylene group (1,3-propanediyl group (-CH ２ CH ２ CH ２ -)) represents.

[0084] In formula (d1), m is preferably an integer from 1 to 500, more preferably an integer from 10 to 300. n is preferably an integer from 1 to 100, more preferably an integer from 1 to 50. a is preferably an integer from 0 to 1000, more preferably an integer from 1 to 500. b is preferably an integer from 0 to 1000, more preferably an integer from 0 to 500.

[0085] Incidentally, the weight average molecular weight of the polyether-modified silicone compound represented by the formula (d1) is preferably 200 to 100,000, more preferably 1,000 to 80,000.

[0086] In the formula (d2), p is preferably an integer of 1 to 500, more preferably an integer of 10 to 300. c and f are preferably integers of 0 to 1000, more preferably integers of 1 to 500. d and e are preferably integers of 0 to 1000, more preferably integers of 0 to 500.

[0087] Incidentally, the weight average molecular weight of the polyether-modified silicone compound represented by the formula (d2) is preferably 200 to 100,000, more preferably 1,000 to 80,000.

[0088] In the formula (d1), the molar fraction of the silicone unit [that is, (m + n) / (m + n + a + b)] is preferably 0.08 to 0.60. When the molar fraction of the silicone unit is 0.08 or more, the mold release property can be sufficiently maintained. When the molar fraction of the silicone unit is 0.60 or less, cloudiness, opacity, etc. in the cured product can be suppressed and transparency can be maintained. From the same viewpoint as above, in the formula (1), the molar fraction of the silicone unit is more preferably 0.10 to 0.50. In the formula (d1), the molar fraction of the polyether unit [that is, (a + b) / (a + b + m + n)] is preferably 0.40 to 0.92. When the molar fraction of the polyether unit is 0.40 or more, cloudiness, opacity, etc. in the cured product can be suppressed and transparency can be maintained. When the molar fraction of the polyether unit is 0.92 or less, the mold release property can be sufficiently maintained. From the same viewpoint as above, in the formula (1), the molar fraction of the polyether unit is more preferably 0.50 to 0.90.

[0089] The molar fractions of the silicone unit and the polyether unit are measured by the following method. The molar fractions of the silicone unit and the polyether unit are １ measured by H-NMR as follows. First, δ ｐｐｍ = 0.4 to 0.6 (Si-CH２ Set the integral value at the chemical shift of —(EO)) to 2. The above integral value means the integral value of the methylene group of the —(EO) moiety. Based on this integral value, calculate the integral values X, Y, and Z at the following chemical shifts respectively. Calculate A by the following formula (N1).A = (((Z / 3) - 3) / 2) + 3... (N1)In formula (N1), Z is the integral value at the chemical shift of δ ２ = -0.2 to 0.2 (CH ｐｐｍ -Si). The above integral value means the integral value of the methyl group of the CH ３ -Si moiety. Calculate B by the following formula (N2). B = ((X - Y - 2) / 4) + (Y / 3)... (N2) In formula (N2), X is the integral value at the chemical shift of δ ３ = 3.2 to 3.9 (CH ｐｐｍ -CH ２ -O). The above integral value means the integral value of the methylene group of the oxyethylene moiety. In formula (N2), Y is the integral value at the chemical shift of δ ２ = 1.0 to 1.2 (CH ｐｐｍ -CH(CH ２ )-O). The above integral value means the integral value of the methyl group of the oxypropylene moiety. The mole fraction of the silicone unit is measured by (A / (A + B)) × 100. The mole fraction of the polyether unit is measured by (B / (A + B)) × 100.

[0090] In formula (d2), the mole fraction of the silicone unit [i.e., p / (p+c+d+e+f)] is preferably 0.08 to 0.60. In formula (d2), a mole fraction of 0.08 or higher for the silicone unit ensures sufficient release properties. In formula (d2), a mole fraction of 0.60 or lower for the silicone unit suppresses clouding, opacity, etc. in the cured product, and maintains transparency. From the same viewpoint as above, in formula (d2), the mole fraction of the silicone unit is more preferably 0.10 to 0.50. In formula (d2), the mole fraction of the polyether unit [i.e., (c+d+e+f) / (c+d+e+f+p)] is preferably 0.40 to 0.92. In formula (d2), a mole fraction of 0.40 or higher for the polyether unit suppresses clouding, opacity, etc. in the cured product, and maintains transparency. In formula (d2), the mole fraction of the polyether unit is 0.92 or less, which ensures sufficient release properties. From the same viewpoint as above, the mole fraction of the polyether unit in formula (d2) is more preferably 0.50 to 0.90.

[0091] The method for measuring the mole fraction of the silicone unit and the polyether unit is the same as the method described above.

[0092] In formulas (d1) and (d2), the total mole fraction of silicone units [i.e., (m+n+p) / (m+n+p+a+b+c+d+e+f)] is preferably 0.08 to 0.60. In formulas (d1) and (d2), a total mole fraction of silicone units of 0.08 or more ensures sufficient release properties. In formulas (d1) and (d2), a total mole fraction of silicone units of 0.60 or less suppresses clouding, opacity, etc., in the cured product and maintains transparency. From the same viewpoint as above, in formulas (1) and (2), the total mole fraction of silicone units is more preferably 0.10 to 0.50.

[0093] In formulas (d1) and (d2), the total mole fraction of polyether units [i.e., (a+b+c+d+e+f) / (a+b+c+d+e+f+m+n+p)] is preferably 0.40 to 0.92. In formulas (d1) and (d2), a total mole fraction of polyether units of 0.40 or more suppresses clouding, opacity, etc. in the cured product and maintains transparency. In formulas (d1) and (d2), a total mole fraction of polyether units of 0.92 or less ensures sufficient release properties. From the same viewpoint as above, in formulas (d1) and (d2), the total mole fraction of polyether units is more preferably 0.50 to 0.90.

[0094] When the polyether-modified silicone compound contains both polyether-modified silicone compound (d1) and polyether-modified silicone compound (d2), the ratio of polyether-modified silicone compound (d1) to polyether-modified silicone compound (d2) (b1:b2) may be 5:95 to 95:5, preferably 10:90 to 90:10, and more preferably 20:80 to 80:20, from the viewpoint of the effects of the second embodiment. The polyether-modified silicone compound may contain at least one type each of polyether-modified silicone compound (d1) and polyether-modified silicone compound (d2), or it may contain two or more types.

[0095] When the photocurable episulfide composition contains a polyether-modified silicone compound, its content is preferably 0.01 parts by mass or more, more preferably 0.03 parts by mass or more, and even more preferably 0.05 parts by mass or more, based on 100 parts by mass of the total amount of the photocurable episulfide composition. From the viewpoint of the transparency of the cured product, the content of the polyether-modified silicone compound is preferably 1.00 parts by mass or less, more preferably 0.50 parts by mass or less, and even more preferably 0.30 parts by mass or less, based on 100 parts by mass of the total amount of the photocurable episulfide composition.

[0096] <UV absorber> The photocurable episulfide composition of the first embodiment may contain at least one UV absorber. The inclusion of a UV absorber in the photocurable episulfide composition improves the weather resistance of the composition or the cured product.

[0097] As the ultraviolet absorber, at least one selected from the group consisting of compounds represented by the following formulas (e-1) to (e-4) is preferred.

[0098]

[0099] In formula (e-1), R １ represents a hydrogen atom or a chlorine atom, R ２ and R ３ Each of these independently represents a substituted or unsubstituted linear or branched alkyl group having 1 to 12 carbon atoms, or an aromatic or heteroaromatic group having 4 to 12 carbon atoms. When a substituted or unsubstituted linear or branched alkyl group having 1 to 12 carbon atoms contains substituents, examples of substituents include aromatic or heteroaromatic groups having 6 to 12 carbon atoms. Examples of aromatic and heteroaromatic groups include phenyl group, biphenyl group, 2,3,5-trimethylphenyl group, furyl group, p-methoxyphenyl group, etc. Commercially available compounds may be used as the compound represented by formula (e-1), for example, Tinuvin 234 (manufactured by BASF Japan Ltd.), Tinuvin 328 (manufactured by BASF Japan Ltd.), etc.

[0100] In formula (e-2), A １ This represents the structure shown by the following formula (e-2a), and R ４ and R ５ Each of these independently represents a structure expressed by the following formula (e-2b).

[0101]

[0102] In equations (e-2a) and (e-2b), Q １ ~Q ５Each of these independently represents a linear or branched alkyl group having 1 to 12 carbon atoms, a linear or branched alkoxy group having 1 to 18 carbon atoms, a halogen, or an aromatic or heteroaromatic group having 4 to 12 carbon atoms. In the linear or branched alkyl group having 1 to 12 carbon atoms, the number of carbon atoms is preferably 1 to 6, and more preferably 1 to 3. Examples of linear or branched alkoxy groups having 1 to 18 carbon atoms include methoxy, butoxy, 2-hydroxy-3-octyloxy-propyroxy, and 2-ethylhexyloxy. Examples of aromatic and heteroaromatic groups include phenyl, biphenyl, 2,3,5-trimethylphenyl, furyl, and p-methoxyphenyl. Commercially available compounds may be used as the compound represented by formula (e-2), such as Tinuvin 405 (manufactured by BASF Japan Ltd.) and Tinuvin 1600 (manufactured by BASF Japan Ltd.).

[0103] In formula (e-3), R ６ and R ７ Each of these independently represents a linear or branched alkyl group having 1 to 6 carbon atoms, or a linear or branched alkoxy group having 1 to 6 carbon atoms. Examples of linear or branched alkyl groups having 1 to 6 carbon atoms in formula (e-3) include methyl, ethyl, butyl, propyl, pentyl, and hexyl groups. Examples of linear or branched alkoxy groups having 1 to 6 carbon atoms include methoxy, ethoxy, butoxy, and phenoxy groups. Commercially available compounds may be used as the compounds represented by formula (e-3), such as Hostavin VSU (manufactured by Clariant Chemicals Co., Ltd.).

[0104] In formula (e-4), R ８ R represents an aromatic group having 6 to 20 carbon atoms, which may be substituted, or an alicyclic group having 5 to 20 carbon atoms, which may be substituted. ９ and R １０Each of these independently represents a linear or branched alkyl group having 1 to 6 carbon atoms. Examples of aromatic groups having 6 to 20 carbon atoms that may be substituted include phenyl, benzyl, benzoyl, and p-methoxybenzyl groups. Examples of alicyclic groups having 5 to 20 carbon atoms that may be substituted include cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclopentanyl, and cyclodecanyl groups. If the aromatic group or alicyclic group contains a substituent, examples of substituents include alkyl groups having 1 to 6 carbon atoms and alkoxy groups having 1 to 6 carbon atoms. A commercially available compound may be used as the compound represented by formula (e-4), for example, Hostavin PR25 (manufactured by Clariant Chemicals Co., Ltd.).

[0105] If the photocurable episulfide composition contains an ultraviolet absorber, its content is preferably 0.01 parts by mass or more, more preferably 0.05 parts by mass or more, and even more preferably 0.10 parts by mass or more, based on 100 parts by mass of the total amount of the photocurable episulfide composition. If the photocurable episulfide composition contains an ultraviolet absorber, its content is preferably 3.00 parts by mass or less, more preferably 2.00 parts by mass or less, and even more preferably 1.00 part by mass or less, based on 100 parts by mass of the total amount of the photocurable episulfide composition.

[0106] (Other Components) The photocurable episulfide composition of the first embodiment may, if necessary, contain other components besides those described above. Other components include, for example, metal catalysts (e.g., metal catalysts containing tin, zinc, bismuth, aluminum, or zirconium), photosensitizers, compounds having epoxy groups, phenolic compounds, compounds having amino groups, inorganic compounds having sulfur atoms, inorganic compounds having selenium atoms, solvents, bluing agents, IR cutters, blue light cutters, reactive diluents, oil-soluble dyes, pigments, fragrances, fillers, adhesion enhancers such as coupling agents, chain extenders, crosslinking agents, defoamers, anti-sedimentation agents, and dispersants. Examples include plasticizers, anti-sagging agents, anti-fouling agents, preservatives, disinfectants, antifungal agents, anti-mold agents, matting agents, thickeners, pigment dispersants, anti-repellent agents, scratch-resistant agents, slip agents, surface modifiers, color separation inhibitors, emulsifiers, anti-skinning agents, desiccants, anti-fouling agents, antistatic agents, conductive agents (electrostatic additives), flame retardants, thermal conductivity improvers, plasticizers, silica microparticles, zirconium oxide microparticles, titanium oxide microparticles, zinc oxide microparticles, silver oxide microparticles, polyolefin microparticles, poly(meth)acrylic microparticles, polyurethane microparticles, etc.

[0107] If the photocurable episulfide composition of the first embodiment contains the above-mentioned other components, their total content may be 0.1 ppm to 70% by mass, 1 ppm to 30% by mass, 10 ppm to 10% by mass, or 0.1% to 5% by mass, based on the total amount of the photocurable episulfide composition.

[0108] [Cured Product] The cured product of the first embodiment of this disclosure is a cured product of the photocurable episulfide composition of the first embodiment described above. The cured product of the first embodiment can be obtained by irradiating the photocurable episulfide composition of the first embodiment with light (i.e., ultraviolet light or visible light) to cause a polymerization reaction of episulfide compound (b) (and other monomers as necessary), thereby curing the photocurable episulfide composition. For this reason, the cured product of the first embodiment may have a shape that is difficult to achieve by heat polymerization.

[0109] The refractive index of the cured product of the first embodiment is preferably 1.60 to 1.80 at 20°C and under sodium D-line light (i.e., light with a wavelength of 589.3 nm).

[0110] When the cured product of the first embodiment is an optical component, specific examples of the optical component include optical adhesives, coatings, optical waveguides, films, lenses, anti-reflective coatings, microlenses, microlens arrays, wafer-level lenses, imaging lenses for cameras (automotive cameras, digital cameras, PC cameras, mobile phone cameras, surveillance cameras, etc.), eyeglass lenses, light beam focusing lenses, light diffusion lenses, camera flash lenses, etc. Among these, the cured product of the first embodiment is particularly preferably an optical waveguide. The optical waveguide that is the cured product of the first embodiment is preferably an optical waveguide for AR (Augmented Reality) glasses, an optical waveguide for VR (Virtual Reality) glasses, or an optical waveguide for optical fibers.

[0111] [Laminate] The laminate of the first embodiment of this disclosure includes the cured product of the first embodiment described above and a substrate. Examples of the cured product included in the laminate include layers disposed on the surface of the substrate (e.g., a coating layer) and layers disposed between multiple substrates (e.g., an adhesive layer). The laminate may also include an intermediate layer disposed between the substrate and the cured product. By placing an intermediate layer between the substrate and the cured product of the first embodiment, for example, the adhesion between the cured product and the substrate can be improved. The material of the intermediate layer is not particularly limited and can be selected according to the purpose of providing the intermediate layer. Specific examples of materials for the intermediate layer include polyurethane aqueous dispersions and transparent adhesives.

[0112] The thickness of the cured material contained in the laminate is not particularly limited. From the viewpoint of photocurability, the thickness of the cured material is preferably 10 mm or less, more preferably 5 mm or less, and even more preferably 3 mm or less. From the viewpoint of ensuring the required performance, the thickness of the cured material is preferably 0.01 μm or more, more preferably 0.05 μm or more, and even more preferably 0.1 μm or more.

[0113] The types of substrates included in the laminate are not particularly limited. Examples include quartz, glass, optical films, ceramic materials, vapor-deposited films, magnetic films, reflective films, metal plates, metal foils, paper, SOG (Spin On Glass), polyester resin, polycarbonate resin, polyimide resin, polyurethane resin, polythiourethane resin, polyepisulfide resin, polyurethane urea resin, polyacrylic resin, polyallyl resin, polyvinyl resin, polyolefin resin, acetylcellulose resin, TFT array substrates, PDP electrode plates, conductive substrates such as metal (e.g., ITO), insulating substrates, semiconductor fabrication substrates such as silicone, silicone nitride, polysilicone, silicone oxide, and amorphous silicone. The laminate may contain only one type of substrate or two or more types.

[0114] If necessary, pretreatment such as etching may be performed on the substrate used for the laminate. Etching methods include alkaline etching, which involves immersion in an alkaline aqueous solution; plasma etching, which involves exposure to a gas plasma such as oxygen; and UV-ozone etching, which involves exposure to ultraviolet light and ozone.

[0115] [Method for producing a cured product] The method for producing a cured product according to the first embodiment includes irradiating the photocurable episulfide composition of the first embodiment described above with ultraviolet light or visible light to obtain a cured product of the photocurable episulfide composition.

[0116] The method for irradiating the photocurable episulfide composition of the first embodiment with ultraviolet or visible light is not particularly limited and can be carried out by known methods. The ultraviolet or visible light preferably includes light with wavelengths of 200 nm to 450 nm. An example of irradiation conditions for ultraviolet or visible light is an irradiation intensity of 0.1 mW / cm². ２ ~1,000mW / cm ２ The cumulative light intensity is 10 mJ / cm². ２ ~30,000mJ / cm ２ Examples of conditions include irradiation time of 0.1 seconds to 500 seconds. Ultraviolet light or visible light may be irradiated directly onto the mixture, or it may be irradiated through an object (such as a mold) that is transparent to ultraviolet light or visible light.

[0117] In the method for producing a cured product of the first embodiment, obtaining a cured product of a photocurable episulfide composition preferably includes injecting the photocurable episulfide composition between a pair of molds, and irradiating the photocurable episulfide composition injected between the pair of molds with ultraviolet light or visible light to obtain a cured product of the photocurable episulfide composition. Examples of the pair of molds include a pair of glass molds and a pair of resin molds. A pair of resin molds is preferred from the viewpoint of easily producing a cured product having fine irregularities on its surface. In particular, a pair of resin molds easily forms fine irregularities on their surface. When fine irregularities are formed on the surface of a pair of resin molds, the irregularities are transferred to the resulting cured product. This results in a cured product having fine irregularities on its surface. A cured product having fine irregularities on its surface is suitable as the optical waveguide described above.

[0118] From the viewpoint of enhancing the polymerizability of episulfide compound (b) (and other monomers as needed), the above method may include heating the mixture. Heating may be performed simultaneously with irradiation of ultraviolet or visible light, before irradiation of ultraviolet or visible light, or after irradiation of ultraviolet or visible light. The heating conditions are not particularly limited. For example, the heating temperature may be selected from 20°C to 200°C, and the heating time may be selected from 0.1 hours to 80 hours.

[0119] From the viewpoint of relieving internal stress generated in the cured product during curing, the above method may include annealing the cured product. The conditions for the annealing treatment are not particularly limited. For example, the treatment temperature may be selected from 50°C to 150°C, preferably 70°C to 140°C, and more preferably 80°C to 130°C.

[0120] ≪Second Embodiment≫

[0121] [Photocurable Episulfide Composition] The photocurable episulfide composition of the second embodiment of the present disclosure contains a photobase generator (a) and an episulfide compound (b), wherein the absolute value of the difference in the Hansen solubility parameters between the photobase generator (a) and the episulfide compound (b) is 3.0 or less, and the molar extinction coefficient at 365 nm of a 0.5 mg / mL acetonitrile solution of the photobase generator (a) is 50 L·mol －１ ・cm －１ The above describes a photocurable episulfide composition.

[0122] The photocurable episulfide composition of the second embodiment exhibits excellent solubility of the photobase generator (a) in the episulfide compound (b) (i.e., compatibility between the photobase generator (a) and the episulfide compound (b)) and excellent photopolymerizability of the episulfide compound (b) (i.e., photocurability of the photocurable episulfide composition). The effect of excellent solubility of the photobase generator (a) in the episulfide compound (b) is obtained by having an absolute value of 3.0 or less for the difference in Hansen solubility parameters between the photobase generator (a) and the episulfide compound (b). The effect of excellent photopolymerizability of the episulfide compound (b) is obtained when the molar extinction coefficient at 365 nm of a 0.5 mg / mL acetonitrile solution of the photobase generator (a) is 50 L·mol. －１ ・cm －１ These are the effects obtained by having the above conditions.

[0123] In the second embodiment, the photocurable episulfide composition has an absolute difference of 3.0 or less between the Hansen solubility parameters of the photobase generator (a) and the episulfide compound (b), and the molar extinction coefficient at 365 nm of a 0.5 mg / mL acetonitrile solution of the photobase generator (a) is 50 L·mol. －１ ・cm －１ Except for being limited to the above and not being particularly limited to the photobase generator (a), the photocurable episulfide composition is the same as in the first embodiment, and the preferred embodiments are also the same.

[0124] The photobase generator (a) in the second embodiment is not particularly limited, and known photobase generators can be used. The photobase generator (a) in the second embodiment is preferably a compound comprising a cationic species having a structure containing a nitrogen cation and an anionic species, and more preferably a compound represented by formula (1) or formula (2) above as the photobase generator (a) in the first embodiment described above.

[0125] [Cured Product] The cured product of the second embodiment of this disclosure differs from the cured product of the first embodiment, which is a cured product of the photocurable episulfide composition of the first embodiment, in that it is a cured product of the photocurable episulfide composition of the second embodiment described above. Except for this point, the cured product of the second embodiment is the same as the cured product of the first embodiment, and the preferred embodiments are also the same.

[0126] [Laminate] The laminate of the second embodiment of this disclosure differs from the laminate of the first embodiment, which includes the cured product of the second embodiment and a substrate, in that it includes the cured product of the second embodiment described above and a substrate. Except for this point, the laminate of the second embodiment is the same as the laminate of the first embodiment, and the preferred embodiments are also the same.

[0127] [Method for Manufacturing Cured Products] The method for manufacturing cured products of the second embodiment of this disclosure differs from the method for manufacturing cured products of the first embodiment, which involves irradiating the photocurable episulfide composition of the first embodiment with ultraviolet light or visible light, in that it includes irradiating the photocurable episulfide composition of the second embodiment described above with ultraviolet light or visible light to obtain a cured product of the photocurable episulfide composition. Except for this point, the method for manufacturing cured products of the second embodiment is the same as the method for manufacturing cured products of the first embodiment, and the preferred embodiments are also the same.

[0128] The following are examples of the present disclosure, but the present disclosure is not limited to these examples. In the following examples, "room temperature" means a temperature range of "15°C to 35°C".

[0129] [Synthesis of Photobases 1-8 as Photobase Generators (a)] Each of Photobases 1-8 was synthesized as a photobase generator (a) by the method described below. In these synthesis, anisole, dichloromethane, and toluene were purchased from Kanto Chemical, thioanisole, ethyl chloroglyoxylate, benzoylformic acid, 1,5-diazabicyclo[4.3.0]-5-nonene, 1,8-diazabicyclo[5.4.0]undec-7-ene, tetrabutylammonium hydroxide (10% in methanol), and tetramethylguanidine were purchased from TCI, aluminum trichloride, anhydrous sodium sulfate, and ethanol were purchased from Fujifilm Wako Pure Chemical Industries, Ltd., and lithium triphenylbutylborate (20% in H ２ O) was purchased from Hokko Chemical Industry Co., Ltd.

[0130] Intermediate 1 and Intermediate 2 were synthesized according to the following procedure, respectively.

[0131] <Synthesis of Intermediate 1 (2-(4-methoxyphenyl)-2-oxoacetic acid)> In a flask, anisole (0.433 g, 4 mmol) and aluminum trichloride (1.067 g, 4.8 mmol) were dissolved in 20 mL of dichloromethane, and this flask was then transferred to a batch of ice water at 0°C. Next, a solution of ethyl chloroglyoxylate (0.437 g, 3.2 mmol) dissolved in 10 mL of dichloromethane was added to this flask dropwise using a dropping funnel. The temperature of the resulting reaction mixture was raised to 25°C and maintained at this temperature for 4 hours. After that, the reaction mixture was poured into 50 mL of ice water and stirred for 5 minutes. Next, the organic phase was separated and recovered from the reaction mixture, and the remaining aqueous phase was extracted twice with dichloromethane (10 mL) to obtain the organic phase. These organic phases were combined, washed with brine, dried over anhydrous sodium sulfate, and then filtered. Dichloromethane was removed from the organic phase after filtration by rotary evaporation under vacuum to obtain a crude intermediate. 9 mL of 1N NaOH aqueous solution was added to the obtained crude product (0.651 g), and the resulting mixture was stirred at room temperature for 3 hours. The aqueous phase of this mixture was then extracted twice with 10 mL of dichloromethane to obtain the organic phase. The remaining aqueous phase was then acidified with 1N HCl solution until the pH was < 3. The acidified aqueous phase was extracted three times with 10 mL of dichloromethane to obtain the organic phase. These organic phases were combined, washed with brine, dried over anhydrous sodium sulfate, and then filtered. The obtained product was concentrated by rotary evaporation under vacuum to obtain 0.33 g of solid product as intermediate 1.

[0132]

[0133] 1 H NMR (400 MHz, CDCl3): δ 3.92 (s, 3H), 6.99 (d, J = 9.2 Hz, 2H), 8.39 (d, J = 9.2 Hz, 2H), 9.13 (broad s, 1H). 13 C NMR (100 MHz, CDCl3): δ55.7, 114.4, 124.6, 134.3, 161.9, 165.8, 182.1.

[0134] <Synthesis of Intermediate 2 (2-(4-(methylthio)phenyl)-2-oxoacetic acid)> Intermediate 2 was synthesized in the same manner as Intermediate 1, except that anisole (0.433 g, 4 mmol) was replaced with thioanisole (0.497 g, 4 mmol), and 0.448 mg of solid product was obtained as Intermediate 2.

[0135]

[0136] 1 H NMR (400 MHz, CDCl3): δ 2.55 (s, 3H), 7.30 (d, J = 9.2 Hz, 2H), 8.29 (d, J = 9.2 Hz, 2H), 9.15 (broad s, 1H). 13 C NMR (100 MHz, CDCl3): δ 14.5, 124.8, 127.7, 131.7, 150.5, 161.6, 182.7.

[0137] <Preparation of Intermediate 3 (2-(Benzo[d][1,3]dioxol-5-yl)-2-oxoacetic acid) and Intermediate 4 (2-(Naphthalen-2-yl)-2-oxoacetic acid)> Intermediate 3 and Intermediate 4 were purchased from Aldrich, respectively.

[0138] <Synthesis of Photobase 1> Intermediate 1 (100 mg, 0.55 mmol) and 1,8-diazabicyclo[5.4.0]undec-7-ene (85 mg, 0.55 mmol) were dissolved in 5 mL of dichloromethane and stirred for 3 hours. The dichloromethane was removed from the resulting mixture by rotary evaporation under vacuum, and 5 mL of diethyl ether was added. The resulting mixture was sonicated for several minutes. The diethyl ether phase was then removed from this mixture, and the resulting product was dried under vacuum to obtain 0.180 g of oil product as Photobase 1. A 0.5 mg / mL acetonitrile solution of the obtained oil product was prepared, and the molar extinction coefficient at 365 nm was measured for this solution. The molar extinction coefficient was 80 L·mol －１ ・cm －１The results were as follows. Here, the molar extinction coefficient of the solution was measured using a UV-Vis spectrophotometer (UV-1800, manufactured by Shimadzu Corporation) with a measurement optical path length of 1 cm (the same procedure was followed for the other photobases).

[0139]

[0140] 1 H NMR (400 MHz, CDCl3): δ 1.73 (m, 6H), 1.99 (m, 2H), 2.86 (m, 2H), 3.45 (m, 6H), 3.85 (s, 3H), 6.91 (d, J = 9.2 Hz, 2H), 8.05 (d, J = 9.2Hz, 2H).

[0141] <Synthesis of Photobase 2> Photobase 2 was synthesized in the same manner as Photobase 1, except that 1,8-diazabicyclo[5.4.0]undec-7-ene (85 mg, 0.55 mmol) was replaced with 1,5-diazabicyclo[4.3.0]non-5-ene (69 mg, 0.55 mmol), yielding 0.220 g of the oil product as Photobase 2.

[0142]

[0143] 1 H NMR (400 MHz, CDCl3): δ 2.01 (m, 2H), 2.12 (m, 2H), 3.06 (t, J = 7.3 Hz, 2H), 3.37 (t, J = 5.5 Hz, 2H), 3.45 (t, J = 5.5 Hz, 2H), 3.60 (t, J = 7.3 Hz, 2H), 3.85 (s, 3H), 6.92 (d, J = 8.7 Hz, 2H), 8.03 (d, J = 8.7 Hz, 2H). 13 C NMR (100 MHz, CDCl3): δ 18.6, 18.7, 29.9, 38.0, 42.4, 53.2, 55.4, 113.6, 127.1, 132.0, 163.5, 164.6, 171.9, 194.9.

[0144] <Synthesis of Photobase 3> Photobase 3 was synthesized in the same manner as Photobase 1, except that 1,8-diazabicyclo[5.4.0]undec-7-ene (85 mg, 0.55 mmol) was replaced with tetrabutylammonium hydroxide (1.44 g, 10% in MeOH, 0.55 mmol), yielding 0.160 g of oil product as Photobase 3.

[0145]

[0146] 1 H NMR (400 MHz, CDCl3): δ 0.98 (t, J = 7.3 Hz, 12H), 1.42 (m, 8H), 1.62 (m, 8H), 2.67 (m, 8H), 3.84 (s, 3H), 6.89 (d, J = 9.1 Hz, 2H), 8.03 (d, J = 9.1 Hz, 2H). 13 C NMR (100 MHz, CDCl3): δ 13.6, 19.6, 23.9, 55.3, 58.6, 113.4, 127.6, 131.9, 163.2, 171.6, 195.8.

[0147] <Synthesis of Photobase 4> Photobase 4 was synthesized in the same manner as Photobase 1, except that intermediate 1 (100 mg, 0.55 mmol) and 1,8-diazabicyclo[5.4.0]undec-7-ene (85 mg, 0.55 mmol) were replaced with intermediate 2 (100 mg, 0.55 mmol) and 1,8-diazabicyclo[5.4.0]undec-7-ene (77 mg, 0.51 mmol), respectively, to obtain 0.170 g of the oil product as Photobase 4.

[0148]

[0149] 1 H NMR (400 MHz, CDCl3): δ 1.65 (m, 2H), 1.72 (m, 4H), 1.99 (m, 2H), 2.50 (s, 3H), 2.82 (m, 2H), 3.43 (m, 6H), 7.24 (d, J = 8.2 Hz, 2H), 7.94 (d, J = 8.2 Hz, 2H). 13C NMR (100 MHz, CDCl3): δ 14.7, 19.5, 23.9, 26.7, 28.9, 32.2, 38.1, 48.5, 54.1, 124.7, 130.0, 130.6, 145.4, 165.9, 171.5, 195.1.

[0150] <Synthesis of Photobase 5> Except for replacing 1,8-diazabicyclo[5.4.0]undec-7-ene (77 mg, 0.51 mmol) with tetramethylguanidine (58 mg, 0.51 mmol), the synthesis of Photobase 5 was carried out in the same manner as for Photobase 4, yielding 0.140 g of solid product. A 0.5 mg / mL acetonitrile solution of the obtained solid product was prepared, and the molar extinction coefficient at 365 nm was measured for this solution. The molar extinction coefficient was 150 L·mol －１ ・cm －１ That was the case.

[0151]

[0152] 1 H NMR (400 MHz, CDCl3): δ 2.49 (s, 3H), 2.93 (s, 12H), 7.23 (d, J = 8.5 Hz, 2H), 7.95 (d, J = 8.5 Hz, 2H), 8.91 (broad s, 1H, NH2+). 13 C NMR (100 MHz, CDCl3): δ 14.7, 39.6, 124.8, 130.0, 130.7, 145.4, 162.2, 171.3, 195.2.

[0153] <Synthesis of Photobase 6> Photobase 6 was synthesized in the same manner as Photobase 1, except that intermediate 1 (100 mg, 0.55 mmol) and 1,8-diazabicyclo[5.4.0]undec-7-ene (85 mg, 0.55 mmol) were replaced with intermediate 3 (100 mg, 0.52 mmol) and 1,5-diazabicyclo[4.3.0]non-5-ene (64 mg, 0.52 mmol), respectively, to obtain 0.150 g of solid product as Photobase 6.

[0154]

[0155] 1 H NMR (400 MHz, CDCl3): δ 2.03 (m, 2H), 2.15 (m, 2H), 3.11 (t, J = 6.9 Hz, 2H), 3.41 (t, J = 5.5 Hz, 2H), 3.48 (t, J = 5.5 Hz, 2H), 3.63 (t, J = 6.9 Hz, 2H), 6.02 (s, 2H), 6.84 (d, J = 8.2 Hz, 1H), 7.52 (s, 1H), 7.71 (d, J = 8.2 Hz, 1H). 13 C NMR (100 MHz, CDCl3): δ 18.7, 18.8, 29.9, 38.0, 42.5, 53.2, 101.6, 107.9, 108.7, 126.8, 129.1, 147.8, 151.6, 164.6, 171.6, 194.4.

[0156] <Synthesis of Photobase 7> Photobase 7 was synthesized in the same manner as Photobase 1, except that intermediate 1 (100 mg, 0.55 mmol) and 1,8-diazabicyclo[5.4.0]undec-7-ene (85 mg, 0.55 mmol) were replaced with intermediate 4 (100 mg, 0.50 mmol) and 1,5-diazabicyclo[4.3.0]non-5-ene (64 mg, 0.50 mmol), respectively, to obtain 0.150 g of the oil product as Photobase 7.

[0157]

[0158] 1 H NMR (400 MHz, CDCl3): δ 1.98 (m, 2H), 2.09 (m, 2H), 3.08 (t, J = 7.4 Hz, 2H), 3.34 (t, J = 5.5 Hz, 2H), 3.46 (t, J = 5.5 Hz, 2H), 3.54 (t, J = 7.4 Hz, 2H), 7.56 (m, 2H), 7.90 (m, 3H), 8.10 (m, 1H), 8.66 (s, 1H). 13C NMR (100 MHz, CDCl3): δ 18.6, 18.7, 29.9, 38.0, 42.4, 53.2, 124.5, 126.4, 127.6, 128.1, 128.2, 129.6, 131.5, 132.5, 132.6, 135.6, 164.6, 171.6, 196.1.

[0159] <Synthesis of Photobase 8> In a flask, 1,5-diazabicyclo[4.3.0]non-5-ene (0.548 g, 4.41 mmol) was dissolved in 20 mL of toluene. Next, a solution of 9-(chloromethyl)anthracene (1 g, 4.41 mmol) dissolved in 30 mL of toluene was added to this flask dropwise using a dropping funnel. After addition, the mixture was stirred at room temperature for 1 hour, and then stirred at 110°C for 3 hours, at which point a precipitate formed. The precipitate was dissolved in distilled water (30 mL), and the toluene was extracted twice with distilled water (10 mL), and the aqueous phases produced by these operations were combined. To the combined aqueous phase, a 20% aqueous solution of lithium triphenylbutylborate (6.75 g, 4.41 mmol) was added dropwise under strong stirring. After complete addition, the resulting mixture was stirred for a further 1 hour, at which point a precipitate formed. The resulting precipitate was filtered and separated, then washed with distilled water and ethanol to obtain a powder. The obtained powder was dispersed in hot ethanol, then cooled to room temperature, filtered and separated, and the separated powder was dried under vacuum to obtain 1.87 g of solid product as photobase 8. A 0.5 mg / mL acetonitrile solution of the obtained solid product was prepared, and the molar extinction coefficient at 365 nm of this solution was measured, and the molar extinction coefficient was 4160 L·mol. －１ ・cm －１ That was the case.

[0160]

[0161] 1H NMR (400 MHz, CDCl3): δ 0.74 (t, J = 7.3 Hz, 3H), 1.01 (m, 4H), 1.23 (m, 4H), 1.74 (m, 2H), 2.33 (m, 4H), 2.59 (t, J = 5.9 Hz, 2H), 3.09 (t, J = 7.3 Hz, 2H), 4.76 (s, 2H), 6.76 (t, J = 7.3 Hz, 3H), 6.93 (t, J = 7.3 Hz, 6H), 7.48 (m, 8H), 7.58 (m, 2H), 7.73 (d, J = 8.2 Hz, 2H), 8.05 (d, J = 8.2 Hz, 2H), 8.53 (s, 1H).

[0162] [Preparation of Photobase C1 and C2 as comparative photobase generators] Photobase C1 and C2 were prepared as comparative photobase generators (hereinafter also referred to as "comparative compounds" or "comparatives") as follows.

[0163] <Preparation of Photobase C1 (Comparative Compound)> Photobase C1 was prepared by referring to International Publication No. 2023 / 063398.

[0164]

[0165] <Synthesis of Photobase C2 (Comparative Compound)> In a flask, 1,5-diazabicyclo[4.3.0]non-5-ene (0.451 g, 3.63 mmol) was dissolved in 10 mL of toluene. Next, a solution of 4-(bromomethyl)benzophenone (1 g, 3.63 mmol) dissolved in 10 mL of toluene was added to this flask dropwise using a dropping funnel. After addition, the mixture was stirred at room temperature for 2 hours, and a precipitate formed. The precipitate was dissolved in distilled water (25 mL), and the toluene was extracted twice with distilled water (10 mL), and the aqueous phases produced by these operations were combined. To the combined aqueous phase, a 20% aqueous solution of lithium triphenylbutylborate (5.56 g, 3.63 mmol) was added dropwise under strong stirring. After complete addition, the resulting mixture was stirred for a further 1 hour. The aqueous phase of the mixture after stirring was collected by CH ２ Cl ２Extraction was performed twice with (20 mL). The obtained organic phase was washed with distilled water (20 mL) and saline solution (20 mL), and then anhydrous NaSO4 was used. ４ The product was dried, then filtered, and then volatile components were removed under vacuum. The product was again dispersed in hot ethanol, cooled to room temperature, then filtered, and then dried under vacuum to obtain 1.94 g of solid product as photobase C2.

[0166]

[0167] 1 H NMR (400 MHz, CDCl3): δ 0.76 (t, J = 7.3 Hz, 3H), 0.96 (m, 4H), 1.22 (m, 2H), 1.47 (m, 2H), 1.64 (m, 2H), 2.10 (t, J = 7.8 Hz, 2H), 2.65 (m, 4H), 3.10 (t, J = 7.8 Hz, 2H), 3.84 (s, 2H), 6.78 (m, 3H), 6.95 (m, 8H), 7.40 (d, J = 6.9 Hz, 6H), 7.47 (t, J = 7.8 Hz, 2H), 7.59 (m, 1H), 7.75 (d, J = 7.8 Hz, 4H).

[0168] [Solubility in each solvent] Each of Photobase 8 as the photobase generator (a) and Photobase C1 as the comparative compound (hereinafter also referred to as "sample") (100 mg) was measured using the Hansen solubility parameter (δ Ｔ The Hansen solubility parameters (δ) of the 12 solvents shown in Table 1 were mixed in 10 mL of each solvent and subjected to ultrasonic shaking. After standing for 1 day, the presence or absence of insoluble matter was visually checked according to the following criteria. S1: 100 mg dissolved per 10 mL of solvent, and no undissolved material was observed in the solution. S2: 100 mg dissolved per 10 mL of solvent, but a small amount of undissolved material was observed. S3: A small amount of 100 mg dissolved per 10 mL of solvent, but almost all of it remained undissolved. S4: No dissolution at all. The results are shown in Table 1. ＴThe values ​​are those described in J. Mater. Chem. A, 2020, 8, 22657. The Hansen solubility parameter (δT) of bis(2,3-epithiopropyl) disulfide (hereinafter also referred to as "E1") (manufactured by Mitsui Chemicals) as episulfide compound (b) was calculated based on the values ​​in J. Mater. Chem. A, 2020, 8, 22657.

[0169] [Hansen solubility parameter (δ Ｔ ) ) Hansen solubility parameter (δ for each sample (E1, Photobase 8, and Photobase C1) Ｔ The maximum dispersion concentration of the sample in each solvent was determined as a function of the solvent exhibiting the highest dispersion concentration. Specifically, the maximum dispersion concentration of the sample in each solvent was determined by the δ of each solvent. Ｔ The plots were then generated. Based on these plots, the Hansen solubility parameter (δ) of the sample was calculated using the B-spline statistical method fitted with OriginPro 2017 software. Ｔ We estimated the following. The results are shown in Table 1.

[0170] [ | △δ Ｔ |=|δ Ｔ (E1)-δ Ｔ (PB) | ] Hansen solubility parameter (δ for each sample (E1, Photobase 8, and Photobase C1) Ｔ Using ), the following formula is used to determine the δ between each photobase (PB) and E1. Ｔ The absolute value of the difference is |Δδ Ｔ We found |. |△δ Ｔ |=|δ Ｔ (E1)-δ Ｔ (PB) | The results are shown in Table 1. Here, the δ between each photobase (PB) and E1 is Ｔ The absolute value of the difference is |Δδ Ｔ The | symbol represents an example of the absolute value of the difference in Hansen solubility parameters between the photobase generator (a) and the episulfide compound (b).

[0171] [Solubility in E1] For each photobase, the solubility in E1 (i.e., compatibility with E1) was judged according to the following criteria. The results are shown in Table 1. -Criteria- A: |ΔδＴ The | is 3.0 or less, and it has excellent solubility in E1. B: |△δ Ｔ The | value is greater than 3.0, indicating poor solubility in E1.

[0172] [Photopolymerizability of E1] The molar extinction coefficient at 365 nm of a 0.5 mg / mL acetonitrile solution of each photobase was measured using the method described above. Based on the obtained molar extinction coefficients, the photopolymerizability of E1 was determined according to the following criteria. The results are shown in Table 1. It should be noted that E1 does not transmit light with wavelengths below 330 nm very well. Therefore, if the molar extinction coefficient of the photobase at 365 nm is high, it can be determined that E1 has excellent photopolymerizability. -Criteria- A: Molar extinction coefficient of 50 mol －１ cm －１ The above results show that E1 has excellent photopolymerization properties. B: Molar extinction coefficient of 50 mol －１ cm －１ It is less than E1 and has inferior photopolymerization properties.

[0173]

[0174] As shown in Table 1, the photobase 8 as the photobase generator (a) is |Δδ Ｔ The | value is 3.0 or less, it has excellent solubility in E1, and the molar extinction coefficient at 365 nm of a 0.5 mg / mL acetonitrile solution is 50 mol. －１ cm －１ The above confirms that E1 exhibits excellent photopolymerization properties. On the other hand, Photobase C1, a comparative photobase generator, showed |Δδ Ｔ The | value is greater than 3.0, it has poor solubility in E1, and the molar extinction coefficient at 365 nm of a 0.5 mg / mL acetonitrile solution is 50 mol. －１ cm －１ It was found to be less than E1, and it was confirmed that it had inferior photopolymerization properties.

[0175] [Examples 1-10, Comparative Examples 1-2] <Preparation of Photocurable Episulfide Composition> In the amount (parts by mass) of E1 shown in the monomer column of Table 2, the type and amount of photobase shown in the photobase column of Table 1 were dissolved. Further, components shown in Table 2 were added as needed to obtain a mixture. The obtained mixture was vigorously stirred for 30 minutes, and then degassed under vacuum while stirring for another 30 minutes. A photocurable episulfide composition was obtained by the above procedure.

[0176] The numerical values ​​in the column for each component in Table 2 represent the amount (parts by mass) of each component, and "-" means that the corresponding component is not present.

[0177] Details of each component shown in Table 2 are as follows: • E1 … Bis(2,3-epithiopropyl) disulfide • T1 … Polythiol compound T1, which is at least one selected from the group consisting 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 • MES … Bis(2-mercaptoethyl) sulfide • UVS-1331 … Sensitizer "Anthracure® UVS-1331" manufactured by Kawasaki Chemical Industries, Ltd. • ITX … 2-isopropylthioxanthone (manufactured by TCI)

[0178] <Laminate Manufacturing (Photocuring)> The photocurable episulfide composition obtained above was applied to a glass substrate using a bar coater to obtain a coating film. The obtained coating film was then exposed to 365 nm wavelength light (UV) for the irradiation time shown in Table 2 (i.e., 30 to 120 seconds (i.e., 3.0 to 6.9 mW / cm²) ２ The coating film was photocured by irradiation (i.e., the monomers in the coating film were photopolymerized) to obtain a cured film as a cured product. Thus, a laminate containing the substrate and the cured product was obtained.

[0179] <Evaluation> The following evaluations were conducted during the above-described procedure. The results are shown in Table 2.

[0180] (Confirmation of photobase solubility in photocurable episulfide composition) The photocurable episulfide composition obtained above was observed, and the solubility of the photobase was confirmed according to the following criteria. -Criteria- A: The photobase was completely dissolved. B: The photobase was partially dissolved. C: The photobase was not dissolved.

[0181] (Photocurability (Curing State)) The state of the cured film in the laminate described above was observed, and the photocurability (i.e., the curing state of the cured film) of the photocurable episulfide composition was confirmed according to the following criteria. -Criteria- A: The cured film was hard and resinous. B: The cured film was soft and gum-like. C: It did not harden and remained liquid.

[0182]

[0183] As shown in Table 2, the photocurable episulfide compositions of Examples 1 to 10 exhibited excellent photocurability to light at a wavelength of 365 nm (i.e., photopolymerization properties of the contained episulfide compounds) and excellent solubility of the photobase. In contrast, the photocurable episulfide compositions of Comparative Examples 1 and 2 exhibited poor solubility of the photobase.

[0184] The disclosure of Japanese Patent Application No. 2024-196497, filed on November 11, 2024, is incorporated herein by reference in its entirety. All documents, patent applications, and technical standards described herein are incorporated herein by reference to the same extent as if each individual document, patent application, and technical standard were specifically and individually noted to be incorporated by reference.

Claims

1. A photocurable episulfide composition comprising a photobase generator (a) and an episulfide compound (b), wherein the photobase generator (a) is a compound represented by the following formula (1) or formula (2). [In formula (1), R represents an aromatic hydrocarbon group which is a phenyl group, naphthyl group, anthracenyl group, or phenanthuryl group, or an unsaturated heterocyclic group which is a pyrrolyl group, furfuryl group, imidazolyl group, pyrazolyl group, oxazolyl group, thiazolyl group, triazolyl group, tetrazolyl group, pyridinium group, triazinyl group, or tetrazinyl group, and the aromatic hydrocarbon group and the unsaturated heterocyclic group may each be substituted with a halogen atom, alkyl group, alkoxy group, alkylthio group, aryl group, alkenyl group, cycloalkyl group, or heterocyclic group, or may be fused with a heterocyclic ring, X ＋ A represents a cation having an ammonium structure, an amidinium structure, a guanidinium structure, or a bigamidium structure. In formula (2), A １ and A ２ Each independently represents a 5-8 membered ring structure, L represents a phenyl group, a naphthyl group, anthracenyl group, or phenanthryl group, and each of the phenyl group, naphthyl group, anthracenyl group, and phenanthryl group may be substituted with a halogen atom, an aliphatic hydrocarbon group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a cyano group, and a heterocyclic group, or may be fused with a heterocyclic ring, R １ ~R ４ Each of these independently represents a C1-C8 alkyl group, a phenyl group, a naphthyl group, an anthracenyl group, or a phenanthrill group, and the phenyl group, naphthyl group, anthracenyl group, and phenanthrill group may be substituted with a halogen atom, an alkyl group, an aryl group, an alkenyl group, a cycloalkyl group, or a heterocyclic group, or may be fused with a heterocyclic group.

2. The photocurable episulfide composition according to claim 1, wherein the absolute value of the difference in Hansen solubility parameters between the photobase generator (a) and the episulfide compound (b) is 3.0 or less.

3. The molar extinction coefficient at 365 nm of a 0.5 mg / mL acetonitrile solution of the photobase generator (a) is 50 L·mol －１ ・cm －１ The above describes the photocurable episulfide composition according to claim 1.

4. The photocurable episulfide composition according to claim 1, wherein the episulfide compound (b) comprises a compound having an episulfide ring and at least one of a sulfide bond and a disulfide bond.

5. The photocurable episulfide composition according to claim 1, wherein the content of the photobase generator (a) relative to the total amount of the episulfide compound (b) is 0.1% to 2% by mass.

6. The photocurable episulfide composition according to claim 1, further comprising a polythiol compound.

7. The polythiol compound is 5,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 4,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 4,8-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 4-mercaptomethyl-1,8-dimercapto-3,6-dithiaoctane, pentaerythritol tetrakis(3-mercaptopropionate), pentaerythritol tetrakis(2-mercaptoacetate), 2,5-bis(mercaptomethyl)- The photocurable episulfide composition according to claim 6, comprising at least one selected from the group consisting of 1,4-dithiane, bis(2-mercaptoethyl)sulfide, 1,1,3,3-tetrakis(mercaptomethylthio)propane, 4,6-bis(mercaptomethylthio)-1,3-dithiane, 2-(2,2-bis(mercaptomethylthio)ethyl)-1,3-dithiethane, 1,1,2,2-tetrakis(mercaptomethylthio)ethane, 3-mercaptomethyl-1,5-dimercapto-2,4-dithiapentane, and tris(mercaptomethylthio)methane.

8. The photocurable episulfide composition according to claim 1, further comprising a polyiso(thio)cyanate compound.

9. The photocurable episulfide composition according to claim 8, wherein the polyiso(thio)cyanate compound comprises at least one selected from the group consisting of pentamethylene diisocyanate, hexamethylene diisocyanate, xylylene diisocyanate, isophorone diisocyanate, bis(isocyanatomethyl)cyclohexane, bis(isocyanatocyclohexyl)methane, 2,5-bis(isocyanatomethyl)bicyclo-[2.2.1]-heptane, 2,6-bis(isocyanatomethyl)bicyclo-[2.2.1]-heptane, tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, and phenylene diisocyanate.

10. A photocurable episulfide composition containing a photo-base generator (a) and an episulfide compound (b), wherein the absolute value of the difference in Hansen solubility parameters between the photo-base generator (a) and the episulfide compound (b) is 3.0 or less, and the molar absorption coefficient at 365 nm of a 0.5 mg / mL acetonitrile solution of the photo-base generator (a) is 50 L·mol －１ ·cm －１ or more.

11. The photocurable episulfide composition according to claim 10, wherein the photobase generator (a) is a compound comprising a cationic species having a structure containing a nitrogen cation and an anionic species.

12. The photocurable episulfide composition according to claim 10, wherein the photobase generator (a) is a compound represented by the following formula (1) or the following formula (2). [In formula (1), R represents an aromatic hydrocarbon group which is a phenyl group, naphthyl group, anthracenyl group, or phenanthuryl group, or an unsaturated heterocyclic group which is a pyrrolyl group, furfuryl group, imidazolyl group, pyrazolyl group, oxazolyl group, thiazolyl group, triazolyl group, tetrazolyl group, pyridinium group, triazinyl group, or tetrazinyl group, and the aromatic hydrocarbon group and the unsaturated heterocyclic group may each be substituted with a halogen atom, alkyl group, alkoxy group, alkylthio group, aryl group, alkenyl group, cycloalkyl group, or heterocyclic group, or may be fused with a heterocyclic ring, X ＋ A represents a cation having an ammonium structure, an amidinium structure, a guanidinium structure, or a bigamidium structure. In formula (2), A １ and A ２ Each independently represents a 5-8 membered ring structure, L represents a phenyl group, a naphthyl group, anthracenyl group, or phenanthryl group, and each of the phenyl group, naphthyl group, anthracenyl group, and phenanthryl group may be substituted with a halogen atom, an aliphatic hydrocarbon group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a cyano group, and a heterocyclic group, or may be fused with a heterocyclic ring, R １ ~R ４ Each of these independently represents a C1-C8 alkyl group, a phenyl group, a naphthyl group, an anthracenyl group, or a phenanthrill group, and the phenyl group, naphthyl group, anthracenyl group, and phenanthrill group may be substituted with a halogen atom, an alkyl group, an aryl group, an alkenyl group, a cycloalkyl group, or a heterocyclic group, or may be fused with a heterocyclic group.

13. The photocurable episulfide composition according to claim 10, wherein the episulfide compound (b) comprises at least one of bis(2,3-epithiopropyl)sulfide and bis(2,3-epithiopropyl)disulfide.

14. A cured product of a photocurable episulfide composition according to any one of claims 1 to 13.

15. The cured product according to claim 14, which is an optical waveguide.

16. A laminate comprising the cured product according to claim 14 and a substrate.

17. A method for producing a cured product, comprising irradiating a photocurable episulfide composition according to any one of claims 1 to 13 with ultraviolet light or visible light to obtain a cured product of the photocurable episulfide composition.

18. A method for producing a cured product according to claim 17, comprising: injecting the photocurable episulfide composition between a pair of resin molds; and irradiating the photocurable episulfide composition injected between the pair of resin molds with ultraviolet light or visible light to obtain a cured product of the photocurable episulfide composition.

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