Curable composition, cured product, optical material, microlens, and diffractive optical element

Abstract

Provided are: a curable composition which contains two or more types of compound A that are represented by general formula (1) and have a Cs or C2v point group, and in which at least one type of the compound A is a compound in which at least one of Ra to Rh is a (meth)acryloylthiooxy group; and a cured product, an optical material, a microlens and a diffractive optical element that are obtained from this curable composition. In the formula, Ra to Rh each denote a hydrogen atom, an alkylsulfanyl group having 1-10 carbon atoms or a (meth)acryloylthiooxy group.　However, the compound A does not include a compound represented by a structural formula. In the formula, R1 denotes a hydrogen atom or a methyl group.

Description

Curable composition, cured product, optical material, microlens, and diffractive optical element

[0001] The present invention relates to a curable composition, a cured product, an optical material, a microlens, and a diffractive optical element.

[0002] In recent years, there has been an increasing demand for optical components requiring a high refractive index, such as microlenses in micro OLED (organic light emitting diode) displays, microlenses for image sensors, and diffractive optical elements in augmented reality glasses (AR glasses). Studies are being conducted to utilize resins exhibiting a high refractive index (high refractive index resins) as materials for such optical components. High refractive index resins can be obtained by polymerizing monomers exhibiting a high refractive index (high refractive index monomers). Naphthalene skeleton-containing monomers are known as an example of high refractive index monomers. However, naphthalene skeleton-containing monomers have high crystallinity due to the naphthalene skeleton, which limits their ease of handling. Patent Document 1, for example, describes a technology to address this issue: 1,6-naphthalenedithiol and its derivatives, which combine a high refractive index with high solubility (compatibility). Furthermore, Patent Document 2 describes a liquid vinylnaphthalene-based composition containing 95 to 51% by mass of 1-vinylnaphthalene and 5 to 49% by mass of 2-vinylnaphthalene, and describes that this composition has excellent storage stability, coatability, and curability.

[0003] International Publication No. 2023 / 058449 Japanese Patent Application Laid-Open No. 2023-158686

[0004] It is known that imprinting technology can be used to fabricate optical components with microstructures on the order of nanometers to micrometers. Imprinting technology is a microfabrication technique that transfers a micropattern onto the surface of a material such as resin by pressing a mold with a desired micropattern structure into the material.

[0005] Imprinting technology consists of the steps of applying a material to a substrate, pressing it with a mold embossed, fixing the transferred pattern by photo- or thermal curing, and finally releasing the mold. The material used for imprinting is temporarily stored in a tank until use, like ink in inkjet printing, and is therefore required to be stable over time and not to crystallize or become cloudy.

[0006] The above-mentioned Patent Document 1 describes that crystalline 1,6-naphthalenedithiol and its derivatives have superior solubility in organic solvents, copolymerization components, etc., and compatibility with polymers and resins, compared to naphthalene disubstituted compounds other than those at the 1,6-position. However, it does not describe a technique for stably storing a composition containing 1,6-naphthalenedithiol or a derivative thereof without crystal precipitation and / or turbidity. Furthermore, the technique described in the above-mentioned Patent Document 2 is a technique for preparing a liquid vinylnaphthalene composition with excellent storage stability by mixing a larger amount of liquid 1-vinylnaphthalene than crystalline 2-vinylnaphthalene, but it lacks versatility for use with substituted naphthalene compounds (monomers) other than 2-vinylnaphthalene. Furthermore, among substituted naphthalene compounds substituted with (meth)acryloylthioxy groups, etc., which have higher crystallinity than vinylnaphthalene compounds, it is believed that there are no compounds that are liquid by themselves, making it difficult to apply the technique described in Patent Document 2 to substituted naphthalene compounds substituted with (meth)acryloylthioxy groups, etc.

[0007] An object of the present invention is to provide a curable composition that exhibits excellent temporal stability in the state of the curable composition before the curing reaction and that can achieve a high refractive index of the resulting cured product. Another object of the present invention is to provide a cured product obtained from the curable composition, and an optical material, a microlens, and a diffractive optical element that include the cured product.

[0008] The above-mentioned object of the present invention has been achieved by the following means: <1> A compound represented by the following general formula (1) and having a point group C ｓ or C ２ｖ and at least one of the compounds A isａ ~R ｈ A curable composition, wherein at least one of the above is a compound having a (meth)acryloylthioxy group. In the above formula, R ａ ~R ｈ represents a hydrogen atom, an alkylsulfanyl group having 1 to 10 carbon atoms, or a (meth)acryloylthioxy group. However, the above compound A does not include compounds represented by the following structural formula: In the above formula, R １ represents a hydrogen atom or a methyl group. <2> The curable composition according to <1>, comprising three or more of the compounds A. <3> At least two of the compounds A have point groups C ｓ <4> The curable composition according to <1> or <2>, wherein all point groups of the compound A are C ｓ <5> The curable composition according to any one of <1> to <4>, wherein the content of each compound A is 10% by mass or more relative to 100% by mass of the total of the compounds A. <6> The curable composition according to any one of <1> to <5>, wherein the content of each compound A is 10% by mass or more relative to 100% by mass of the total of the compounds A. <7> A cured product obtained from the curable composition according to any one of <1> to <6>. <8> An optical material comprising the cured product according to <7>. <9> A microlens or a diffractive optical element comprising the cured product according to <7>.

[0009] In the present invention, when there are multiple substituents or linking groups, etc., represented by a specific symbol or formula (hereinafter referred to as substituents, etc.), or when multiple substituents, etc. are specified simultaneously, unless otherwise specified, the respective substituents, etc. may be the same or different from each other (regardless of the presence or absence of the expression "independently," the respective substituents, etc. may be the same or different from each other). This also applies to the specification of the number of substituents, etc. Furthermore, when multiple substituents, etc., are adjacent to each other (especially when they are adjacent), they may be linked to each other to form a ring, unless otherwise specified. Furthermore, unless otherwise specified, rings, such as alicyclic rings, aromatic rings, and heterocyclic rings, may be further condensed to form a fused ring. In the present invention, unless otherwise specified, with respect to double bonds, when E- and Z-configurations exist in a molecule, they may be either one of them, or a mixture thereof. Furthermore, in the present invention, unless otherwise specified, when a compound has one or more asymmetric carbons, the stereochemistry of such asymmetric carbons can each independently be either an (R) or (S) configuration. As a result, the compound may be a mixture of stereoisomers such as optical isomers or diastereoisomers, or may be a racemate. However, when counting the types of compound A, the types of structural isomers are counted, and stereoisomers are not counted as different types. Furthermore, in the present invention, the expressions for compounds and monomers include those in which a part of the structure has been changed, as long as the effects of the present invention are not impaired. In the present invention, for substituents (similar to linking groups and rings) that are not specified as substituted or unsubstituted, it means that the group may have any substituent, as long as the desired effects are not impaired. For example, when referring to an "alkyl group," it means that both an unsubstituted alkyl group and a substituted alkyl group are included. For example, R in general formula (1) ａ ~R ｈThe alkyl group in the alkylsulfanyl group having 1 to 10 carbon atoms, which can be represented by the formula (I), may have a substituent, as described below. In the present invention, when the number of carbon atoms of a certain group is specified, this number of carbon atoms means the number of carbon atoms of the entire group, unless otherwise specified in the present invention or this specification. In other words, when this group further has a substituent, it means the total number of carbon atoms including the substituent.

[0010] In the present invention, when describing physical properties and the like by showing a numerical range, if the upper and lower limits of the numerical range are described separately, any of the upper and lower limits can be appropriately combined to form a specific numerical range. On the other hand, when describing multiple numerical ranges represented using "to", the upper and lower limits forming the numerical range are not limited to the combination of the specific upper and lower limits written before and after "to" as a specific numerical range, and can be a numerical range obtained by appropriately combining the upper and lower limits of each numerical range. Note that in the present invention, a numerical range represented using "to" means a range that includes the numerical values ​​written before and after "to" as the upper and lower limits. In the curable composition of the present invention, each component may be used alone or in a mixture of two or more types, unless otherwise specified. The same applies to the cured product, optical material, microlens, and diffractive optical element obtained from the curable composition of the present invention.

[0011] In the present invention, "(meth)acrylate" refers to either or both of acrylate and methacrylate, "(meth)acrylic acid" refers to either or both of acrylic acid and methacrylic acid, and "(meth)acryloyl" refers to either or both of acryloyl and methacryloyl. Furthermore, "(meth)acrylic thioester" refers to either or both of acrylic acid S-ester and methacrylic acid S-ester, and means an ester of (meth)acrylic S-acid, which is an S-acid (-C(=O)SH). In the present invention, monomers are distinguished from oligomers and polymers based on molecular weight, and a compound having a weight-average molecular weight of 1,000 or less is called a monomer.

[0012] The curable composition of the present invention exhibits excellent stability over time in a state before the curing reaction, and can achieve a high refractive index in the resulting cured product. The cured product, optical material, microlens, and diffractive optical element of the present invention can also exhibit a high refractive index.

[0013] FIG. 1 is a schematic cross-sectional view illustrating a method for producing a cured product of the present invention by imprinting using the curable composition of the present invention.

[0014] [Curable Composition] The curable composition of the present invention is a compound represented by the general formula (1) shown below and having a point group C ｓ or C ２ｖ and at least one of the compounds A is R in general formula (1) described below. ａ ~R ｈ wherein at least one of the following is a (meth)acryloylthioxy group. However, the compound A does not include the compound represented by the following structural formula. In other words, in the present invention, the compound represented by the following structural formula is not the compound A.

[0015]

[0016] In the above formula, R １ represents a hydrogen atom or a methyl group. ３ and -SC(=O)C(R １ ) = CH ２ may be bonded to any of the carbon atoms 1 to 8 of naphthalene.

[0017] In the present invention, the curable composition means a composition that has curability and can give a cured product (resin) by a curing reaction.

[0018] The compound A contained in the curable composition of the present invention is a compound represented by the general formula (1) below, which has a substituent R on a naphthalene ring. ａ ~R ｈ Among naphthalene compounds which may have an alkylsulfanyl group or a (meth)acryloylthioxy group having 1 to 10 carbon atoms as the alkyl group, ｓ or C ２ｖIn the curable composition of the present invention, at least one of the compounds A is a substituted naphthalene compound having a substituent R on the naphthalene ring. ａ ~R ｈ The curable composition of the present invention contains two or more substituted naphthalene compounds (compounds A) having the specific chemical structure and the specific point group, and therefore, although all of the compounds A are highly crystalline, when they are made into a curable composition, they exhibit excellent stability over time in the state of the curable composition before the curing reaction, and the resulting cured product can have a high refractive index.

[0019] The point group that the compound represented by the general formula (1) described later can take is C ｓ or C ２ｖ , and unsubstituted naphthalene adopts D ２ｈ Besides, C ２ｈ Here, C ２ｖ is C ２ It has a rotation axis and a vertical mirror plane, and C ２ｈ is C ２ Since it has a rotation axis and a horizontal plane of symmetry, C ２ｖ and C ２ｈ However, among the compounds represented by the general formula (1) described below, C ２ｈ In a combination of two or more including C ｓ or C ２ｖ Even if combined with C, the stability over time is poor. ｓ and C ２ｖ It has been found that excellent stability over time is only exhibited when two or more compounds selected from the following are combined. This will be explained in more detail below, based on a comparison between Examples and Comparative Examples described later. Comparative curable composition No. c14 is a compound represented by general formula (1) in which the point group is C ｓ Compound (A-4) (the above compound A) and compound (A-5) (the above compound A) ２ｈWhen the curable composition is concentrated to prepare it, at least one of crystal precipitation and turbidity occurs within just 2 hours. ｓ Compound (A-4) (the above compound A) and compound (A-5) (the above compound A) ２Ｖ In the curable composition No. 102 of the present invention, which contains the compound (A-8) (above-mentioned compound A) represented by the general formula (1), the liquid is stable for 2 days or more (48 hours or more) at 25°C, and crystal precipitation and turbidity are unlikely to occur. In addition, the curable composition No. c15 for comparison contains the compound represented by the general formula (1) represented by the point group C ２ｖ Compound (A-8) (the above compound A) and compound (A-9) (the above compound A) ２ｈ When the curable composition is concentrated to prepare it, at least one of crystal precipitation and turbidity occurs within just 2 hours. ２ｖ Compound (A-8) (the above compound A) and compound (A-9) (the above compound A) ２Ｖ In the curable composition No. 101 of the present invention containing the compound (A-21) (the compound A) represented by the formula (I), the liquid is stable for 2 days or more (48 hours or more) at 25°C, and crystal precipitation and turbidity are unlikely to occur.

[0020] The components contained in the curable composition of the present invention will be described below in order.

[0021] <Compound A> The compound A is represented by the following general formula (1) and has a point group C ｓ or C ２ｖ It is a compound in which

[0022] (Compound represented by general formula (1))

[0023] In the above formula, R ａ ~R ｈ represents a hydrogen atom, an alkylsulfanyl group having 1 to 10 carbon atoms (alkyl group -S-), or a (meth)acryloylthioxy group.

[0024] R ａ ~R ｈThe alkyl group in the alkylsulfanyl group having 1 to 10 carbon atoms, which can be taken as R, may be either linear or branched, and the number of carbon atoms in the alkyl group may be 1 to 10, preferably 1 to 7, more preferably 1 to 5, and even more preferably 1 to 3. Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a pentyl group, a 1-methylbutyl group, a 3-methylbutyl group, a hexyl group, a 1-methylpentyl group, a 4-methylpentyl group, a heptyl group, a 1-methylhexyl group, a 5-methylhexyl group, a 2-ethylhexyl group, an octyl group, a 1-methylheptyl group, a nonyl group, a 1-methyloctyl group, a nonyl group, and a decyl group, and a methyl group or an ethyl group is preferred. ａ ~R ｈ The alkyl group in the alkylsulfanyl group having 1 to 10 carbon atoms which can be taken as R may have a substituent, and examples of the alkyl group having such a substituent include a halogenated alkyl group and a hydroxyalkyl group. Examples of the halogen atom constituting the halogenated alkyl group include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. R ａ ~R ｈ The alkylsulfanyl group having 1 to 10 carbon atoms that can be taken as the alkylsulfanyl group is preferably a methylsulfanyl group or an ethylsulfanyl group.

[0025] R ａ ~R ｈ Among the (meth)acryloylthioxy groups that can be taken as above, the acryloylthioxy group is a group represented by the following formula (Pol-1), and the methacryloylthioxy group is a group represented by the following formula (Pol-2). In the following formulas, * indicates a bond.

[0026]

[0027] R ａ ~R ｈ Among the eight groups, the number of groups that are alkylsulfanyl groups or (meth)acryloylthioxy groups having 1 to 10 carbon atoms is determined based on the point group of the compound represented by the general formula (1) being C ｓ or C ２ｖAs long as R ａ ~R ｈ Among the eight groups, the number of groups that are (meth)acryloylthioxy groups is, for example, preferably 0 to 4, and more preferably 0 to 3, from the viewpoint of obtaining a good cured product. However, at least one of the compounds A contained in the curable composition of the present invention is ａ ~R ｈ At least one of the above is a (meth)acryloylthioxy group.

[0028] (Point Group) The compound A is represented by the general formula (1) and has a point group C ｓ or C ２ｖ The point group of the compound A is C ｓ In addition, the compound represented by the general formula (1) is preferably ａ ~R ｈ The structure includes unsubstituted naphthalene, where is a hydrogen atom. However, unsubstituted naphthalene has a point group of D ２ｈ Therefore, it is not included in the above-mentioned compound A. Therefore, the above-mentioned compound A is a substituted naphthalene compound having at least one alkylsulfanyl group or (meth)acryloylthioxy group having 1 to 10 carbon atoms as a substituent.

[0029] In the compound A, a monosubstituted compound having one substituent (hereinafter referred to as "substituent A") selected from an alkylsulfanyl group having 1 to 10 carbon atoms and a (meth)acryloylthioxy group, the position where the substituent A is present is R ａ and R ｂ In the case of a disubstituted compound having two substituents A among the compound A, the position where the substituent A is present may be any of R ａ and R ｂ , R ａ and R ｃ , R ａ and R ｄ , R ａ and R ｆ , R ａ and R ｇ , Rａ and R ｈ , R ｂ and R ｃ , or R ｂ and R ｇ In the compound A, in a tri-substituted compound having three substituents A, the position where the substituent A is present is preferably R ａ , R ｃ and R ｆ The combination of R ａ , R ｃ and R ｇ or a combination of R ｂ , R ｃ and R ｇ In the compound A, in a tetrasubstituted compound having four substituents A, the position where the substituent A is present is preferably a combination of R ａ , R ｃ , R ｆ and R ｇ or a combination of R ａ , R ｃ , R ｆ and R ｈ The combination is preferred.

[0030] Preferred specific examples of Compound A are listed below, but the present invention is not limited to these compounds. In the following, Me represents a methyl group, Et represents an ethyl group, and * represents a bond. In addition, point groups are written in parentheses below the compound numbers.

[0031]

[0032]

[0033] The molecular weight of the compound A is preferably 174 to 820, more preferably 174 to 670, and even more preferably 174 to 530.

[0034] The compound A can be synthesized by a conventional method. For example, it can be synthesized with reference to the synthesis methods described in JP-A-2013-155118 (Sumitomo Seika Chemicals) and JP-A-3-170456 (Sumitomo Seika Chemicals). Furthermore, it can be synthesized with reference to the methods described in the examples, as appropriate.

[0035] The curable composition of the present invention contains two or more types of the compound A. As shown in comparative curable composition Nos. c11 and c12 described later, the compound A is a compound with very high crystallinity when used alone, but the curable composition of the present invention exhibits excellent stability over time by containing two or more types of the compound A. From the viewpoint of further improving stability over time, the curable composition of the present invention preferably contains three or more types of the compound A. There are no particular restrictions on the combination of two or more types (preferably three or more types) of the compound A contained in the curable composition of the present invention, and for example, ｓ Only the compound A may be two or more kinds, and the point group is C ２ｖ Only the compound A may be two or more kinds, and the point group is C ｓ and one or more compounds A having a point group C ２ｖ From the viewpoint of further improving the stability over time, the point groups of the compound A contained in the curable composition of the present invention may be such that at least two of the point groups of the compound A are C ｓ It is preferable that all the point groups of the compound A are C ｓ It is more preferable that the content of each compound A in 100% by mass of the total amount of the compounds A (meaning "the sum of all of the compounds A contained in the curable composition of the present invention") (i.e., the proportion of each compound A in 100% by mass of the total amount of the compounds A) is not particularly limited as long as the effects of the present invention are exhibited, and for example, each can be 5% by mass or more, preferably 7% by mass or more, and from the viewpoint of further improving the stability over time, it is more preferable that each is 10% by mass or more. Note that the upper limit value is appropriately determined depending on how many types of compounds A are contained in the curable composition of the present invention, so that the lower limit value of each compound A is 10% by mass or more.

[0036] The two or more compounds A contained in the curable composition of the present invention may be, for example, R ｂ monosubstituted compounds having a substituent A in R ａ and R ｆ a disubstituted compound having two substituents A in R ｂ and Rｇ Disubstituted compounds having two substituents A in R ａ , R ｃ and R ｆ A preferred example is a combination of two or more of tri-substituted compounds having three substituents A in R ｂ a combination of two or more monosubstituted compounds having a substituent A in R ａ and R ｆ a combination of two or more disubstituted compounds having two substituents A in R ｂ and R ｇ a combination of two or more disubstituted compounds having two substituents A in R ａ , R ｃ and R ｆ Also included is a combination of two or more tri-substituted compounds each having three substituents A in R ａ and R ｆ a combination of two or more disubstituted compounds having two substituents A in R ｂ and R ｇ a combination of two or more disubstituted compounds having two substituents A in R ａ and R ｆ A disubstituted compound having two substituents A in R ｂ and R ｇ and a disubstituted compound having two substituents A in R ａ and R ｆ A disubstituted compound having two substituents A in R ｂ and R ｇ and at least one disubstituted compound having two substituents A in R ａ , R ｃ and R ｆ a trisubstituted compound having three substituents A in R ｂ a monosubstituted compound having a substituent A in R ａ and R ｆ A disubstituted compound having two substituents A in R ｂ and R ｇ at least one disubstituted compound having two substituents A in R ａ , R ｃ and R ｆand a tri-substituted compound having three substituents A. In these combinations of two or more compounds A, the descriptions of the substituents, point groups, and content in general formula (1) above can be preferably applied to the substituents, point groups, and content in general formula (1), respectively.

[0037] As described above, the cured product obtained from the curable composition of the present invention can achieve a high refractive index, and the composition can exhibit excellent stability over time even when the concentration of the compound A in the curable composition is high. When the curable composition of the present invention contains the compound A at a high concentration, the total content of the compound A in the curable composition of the present invention can be, for example, 97.00 to 99.99 mass%, preferably 98.00 to 99.95 mass%, more preferably 99.00 to 99.90 mass%, and even more preferably 99.00 to 99.70 mass%.

[0038] When the curable composition of the present invention contains other monomers (hereinafter referred to as "other monomers") other than the above-described compound A, such as a (meth)acrylic (thio) acid ester compound described below, the total content of the compound A in the curable composition of the present invention can be, for example, 60 to 99 mass%, preferably 65 to 99 mass%, more preferably 70 to 95 mass%, even more preferably 75 to 90 mass%, and particularly preferably 75 to 85 mass%.

[0039] <Other Components> The curable composition of the present invention may further contain other components in addition to the above-described Compound A. Examples of the other components include other monomers such as (meth)acrylic (thio) acid ester compounds (excluding the above-described Compound A), and photoradical polymerization initiators.

[0040] ((Meth)acrylic(thio)acid ester compound) The curable composition of the present invention preferably contains, in addition to the above-mentioned compound A, a (meth)acrylic(thio)acid ester compound (excluding the above-mentioned compound A) as another monomer. The (meth)acrylic(thio)acid ester compound refers to both a (meth)acrylic acid ester compound and a (meth)acrylic thioic acid S-ester compound. Examples of the (meth)acrylic(thio)acid ester compound include monofunctional mono(meth)acrylic(thio)acid ester compounds, difunctional di(meth)acrylic(thio)acid ester compounds, and trifunctional or higher polyfunctional (meth)acrylic(thio)acid ester compounds, depending on the number of (meth)acryloyl groups that are functional groups.

[0041] Specific examples of the mono(meth)acrylic (thio) acid ester compound include tetrahydrofurfuryl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, 2-methoxyethyl (meth)acrylate, methoxytriethylene glycol (meth)acrylate, 2-ethoxyethyl (meth)acrylate, 3-methoxybutyl (meth)acrylate, and 1-ethoxyethyl (meth)acrylate. , butoxyethyl (meth)acrylate, ethoxydiethylene glycol (meth)acrylate, methoxydiethylene glycol (meth)acrylate, ethyl diglycol (meth)acrylate, cyclic trimethylolpropane formal mono(meth)acrylate, imide (meth)acrylate, isoamyl (meth)acrylate, ethoxylated succinic acid (meth)acrylate, trifluoroethyl (meth)acrylate, ω-carboxypolycaprolactone mono(meth)acrylate, cyclohexyl (meth)acrylate acrylate, 2-(2-ethoxyethoxy)ethyl (meth)acrylate, diethylene glycol monobutyl ether (meth)acrylate, caprolactone (meth)acrylate, methoxypolyethylene glycol (350) mono(meth)acrylate, methoxypolyethylene glycol (550) mono(meth)acrylate, phenoxyethyl (meth)acrylate, benzyl (meth)acrylate, methylphenoxyethyl (meth)acrylate, caprolactone-modified tetrahydrofurfuryl (meth)acrylate tribromophenyl (meth)acrylate, ethoxylated tribromophenyl (meth)acrylate, 2-phenoxyethyl (meth)acrylate, an ethylene oxide adduct of 2-phenoxyethyl (meth)acrylate, a propylene oxide adduct of 2-phenoxyethyl (meth)acrylate, phenoxydiethylene glycol (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, and 3-(meth)acryloyloxymethylcyclohexene oxide.Specific product names and sources of the mono(meth)acrylic (thio) acid ester compounds include ethoxylated orthophenylphenol acrylate (NK Ester A-LEN-10, manufactured by Shin-Nakamura Chemical Co., Ltd.) and m-phenoxybenzyl acrylate (Light Acrylate POB-A, manufactured by Kyoeisha Chemical Co., Ltd.).

[0042] Specific examples of the di(meth)acrylic (thio) acid ester compound include di(meth)acrylates of diols and di(meth)acrylates of (poly)alkylene glycols. Specific product names and sources of di(meth)acrylic (thio) acid ester compounds include 1,6-hexanediol diacrylate (NK Ester A-HD-N, manufactured by Shin-Nakamura Chemical Co., Ltd.; Light Acrylate 1,6HX-A, manufactured by Kyoeisha Chemical Co., Ltd.), 1,9-nonanediol diacrylate (NK Ester A-NOD-N, manufactured by Shin-Nakamura Chemical Co., Ltd.; Light Acrylate 1,9ND-A, manufactured by Kyoeisha Chemical Co., Ltd.), 1,10-decanediol diacrylate (NK Ester A-DOD-N, manufactured by Shin-Nakamura Chemical Co., Ltd.), neopentyl glycol diacrylate (NK Ester A-NPG, manufactured by Shin-Nakamura Chemical Co., Ltd.; Light Acrylate NP-A, manufactured by Kyoeisha Chemical Co., Ltd.), ethylene glycol diacrylate (SR206NS, manufactured by Arkema), polyethylene glycol diacrylate (NK Ester A-40 0, manufactured by Shin-Nakamura Chemical Co., Ltd.), polypropylene glycol diacrylate (NK Ester APG-400, manufactured by Shin-Nakamura Chemical Co., Ltd.), 1,3-butanediol dimethacrylate (NK Ester BG, manufactured by Shin-Nakamura Chemical Co., Ltd.), 1,4-butanediol dimethacrylate (NK Ester BD, manufactured by Shin-Nakamura Chemical Co., Ltd.), 1,6-hexanediol dimethacrylate (NK Ester HD-N, manufactured by Shin-Nakamura Chemical Co., Ltd.), 1,9-nonanediol dimethacrylate (NK Ester NOD-N, manufactured by Shin-Nakamura Chemical Co., Ltd.), 1,10-decanediol dimethacrylate (NK Ester DOD-N, manufactured by Shin-Nakamura Chemical Co., Ltd.), 1,12-dodecanediol dimethacrylate (SR262, manufactured by Sartomer), neopentyl glycol dimethacrylate (NK Ester NPG, manufactured by Shin-Nakamura Chemical Co., Ltd.), and the like.

[0043] Specific product names and sources of polyfunctional (meth)acrylic (thio) acid ester compounds include trifunctional (meth)acrylic (thio) acid ester compounds such as trimethylolpropane triacrylate (NK Ester A-TMPT, manufactured by Shin-Nakamura Chemical Co., Ltd.; Light Acrylate TMP-A, manufactured by Kyoeisha Chemical Co., Ltd.), ethoxylated trimethylolpropane triacrylate (NK Ester A-TMPT-EO, manufactured by Shin-Nakamura Chemical Co., Ltd.), ethoxylated glycerin triacrylate (NK Ester A-GLY-6E, manufactured by Shin-Nakamura Chemical Co., Ltd.), and propoxylated glycerin triacrylate (NK Ester A-GLY-3P, manufactured by Shin-Nakamura Chemical Co., Ltd.); Examples of suitable (meth)acrylic (thio) acid ester compounds include tetrafunctional (meth)acrylic (thio) acid ester compounds such as pentaerythritol tetraacrylate (NK Ester A-TMMT, manufactured by Shin-Nakamura Chemical Co., Ltd.), ethoxylated pentaerythritol tetraacrylate (NK Ester ATM-4E, manufactured by Shin-Nakamura Chemical Co., Ltd.), and ditrimethylolpropane tetraacrylate (NK Ester AD-TMP-L, manufactured by Shin-Nakamura Chemical Co., Ltd.); pentafunctional (meth)acrylic (thio) acid ester compounds such as dipentaerythritol pentaacrylate (M-402, manufactured by Toagosei Co., Ltd.); and hexafunctional (meth)acrylic (thio) acid ester compounds such as dipentaerythritol hexaacrylate (GM66G0H, manufactured by Kokusei Chemical Co., Ltd.).

[0044] Preferred specific examples of the (meth)acrylic (thio) acid ester compound are listed below, but the present invention is not limited to these compounds.

[0045]

[0046] There is no particular limitation on the method for obtaining the (meth)acrylic (thio) acid ester compound, and the compound may be commercially available or synthesized by a conventional method.

[0047] When the curable composition of the present invention contains a (meth)acrylic(thio) acid ester compound, the content of the (meth)acrylic(thio) acid ester compound in the curable composition of the present invention can be, for example, 1 to 40 mass%, preferably 1 to 35 mass%, more preferably 5 to 30 mass%, even more preferably 10 to 25 mass%, and particularly preferably 15 to 25 mass%. By controlling the amount of the (meth)acrylic(thio) acid ester compound in the curable composition, it is possible to adjust the function of alleviating stress when the cured product undergoes thermal change.

[0048] When the curable composition of the present invention contains a (meth)acrylic (thio) acid ester compound, the curable composition of the present invention may contain two or more kinds of (meth)acrylic (thio) acid ester compounds. When two or more kinds of (meth)acrylic (thio) acid ester compounds are contained, it is preferable that the total content is within the above range.

[0049] (Photoradical polymerization initiator) The curable composition of the present invention preferably contains a photoradical polymerization initiator. The curable composition of the present invention can obtain a cured product exhibiting a high refractive index by photopolymerization due to the action of the photoradical polymerization initiator. As the photoradical polymerization initiator, compounds commonly used as photoradical polymerization initiators can be used appropriately depending on the conditions of the photopolymerization (photocuring) step described below, and specifically the following compounds can be used. For example, 1,2-diphenylethanedione, methylphenyl glyoxylate; α-acylphosphine compounds such as bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide, bis(2,6-dimethylbenzoyl)-2,4,4-trimethylpentylphosphine oxide, bis(2,4,6-trimethylbenzoyl)-2,4,4-trimethylpentylphosphine oxide, bis(2,6-dichlorobenzoyl)-2,4,4-trimethylpentylphosphine oxide, (2,4,6-trimethylbenzoyl)diphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, and ethylphenyl(2,4,6-trimethylbenzoyl)phosphinate (also known as (2,4,6-trimethylbenzoyl)ethoxyphenylphosphine oxide). α-hydroxyketone compounds such as 1-phenyl-2-hydroxy-2-methylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropan-1-one, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methylpropan-1-one, 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]phenyl}-2-methylpropan-1-one; benzyl ketal compounds such as 2,2-dimethoxy-1,2-diphenylethan-1-one; α-aminoketone compounds such as 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-1-butanone;Examples of oxime ester compounds include 1-[4-(phenylthio)phenyl]octane-1,2-dione 2-(O-benzoyloxime) (available from BASF Japan under the trade name Irgacure OXE01), 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]ethanone O-acetyloxime (available from BASF Japan under the trade name Irgacure OXE02), Irgacure OXE03 and Irgacure OXE04 (all trade names, available from BASF Japan), and ADEKA ARCLES N-1919T, ADEKA ARCLES NCI-831E, ADEKA ARCLES NCI-930 and ADEKA ARCLES NCI-730 (all trade names, available from ADEKA).

[0050] Among these, in the present invention, as the photoradical polymerization initiator, 1-hydroxycyclohexyl phenyl ketone (available from BASF Japan Ltd. under the trade name of Irgacure 184), bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide (available from BASF Japan Ltd. under the trade name of Irgacure 819), (2,4,6-trimethylbenzoyl)diphenylphosphine oxide (available from BASF Japan Ltd. under the trade name of Irgacure TPO), 2,2-dimethoxy-1,2-diphenylethane-1,2-diol, 2,4,6-trimethylbenzoyldiphenylphosphine oxide (available from BASF Japan Ltd. under the trade name of Irgacure TPO), ... 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methylpropan-1-one, 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one, ethylphenyl(2,4,6-trimethylbenzoyl)phosphinate (available from BASF Japan as Irgacure TPO-L (trade name) or from ADEKA Corporation as Adeka Arcles NCI-831E (trade name)) can be preferably used. The photoradical polymerization initiator may contain one type, or two or more types.

[0051] When a photoradical polymerization initiator is contained, the content of the photoradical polymerization initiator in the curable composition of the present invention is preferably 0.01 to 5.00 mass%, more preferably 0.05 to 1.00 mass%, and even more preferably 0.05 to 0.50 mass%.

[0052] Unless contrary to the spirit of the present invention, the curable composition of the present invention may contain polymers or monomers other than the above-mentioned components, inorganic particles, dispersants, plasticizers, heat stabilizers, mold release agents, solvents, etc. It is preferable to keep the content of inorganic particles in the curable composition to 30 mass% or less.

[0053] The viscosity of the curable composition of the present invention at 60°C is preferably less than 50 mPa·s, more preferably less than 35 mPa·s, even more preferably less than 30 mPa·s, and particularly preferably less than 25 mPa·s, from the viewpoints of improving handleability when forming a cured product, particularly improving mold conformability when imprinting, and forming a higher quality cured product. There is no particular restriction on the lower limit, but a viscosity of 1 mPa·s or more is practical. The viscosity of the curable composition can be measured using a rheometer (for example, trade name: HAAKE RheoStress 6000, manufactured by Thermo Fisher Scientific) at a shear rate of 10 s －１ The viscosity is measured under the condition of 60°C.

[0054] The curable composition of the present invention can be used to produce a cured product that is required to have a high refractive index. In particular, the curable composition of the present invention has excellent stability over time, and is therefore preferably used as a material for imprinting, such as nanoimprinting, to produce a cured product that exhibits a high refractive index.

[0055] [Method for Preparing Curable Composition] The method for preparing the curable composition of the present invention is not particularly limited, as long as the curable composition of the present invention contains two or more types of the compound A. For example, the curable composition is preferably prepared by mixing two or more types of the compound A. The mixing of two or more types of the compound A may be carried out in the presence of an organic solvent. For example, a mixed solution of two or more types of the compound A can be prepared by stirring and mixing two or more types of the compound A in the presence of an organic solvent, and then removing the organic solvent from the resulting mixed solution. The organic solvent is preferably one in which two or more types of the compound A are soluble. Examples of the organic solvent include hydrocarbon solvents such as aromatic hydrocarbon solvents such as toluene, halogenated hydrocarbon solvents such as chlorinated hydrocarbon solvents such as methylene chloride and chloroform, alcohol solvents such as methanol, ether solvents such as cyclic ether solvents such as tetrahydrofuran, epihalohydrin solvents such as epichlorohydrin, glycol ether acetate solvents such as (poly)alkylene glycol monoalkyl ether acetate, ester solvents such as ethyl acetate, amide solvents such as N,N-dimethylformamide, urea solvents, and the like. The organic solvent can be removed by a conventional method, for example, by distillation under heating and / or reduced pressure. Components other than the compound A may be added at the stage of mixing two or more of the compounds A, or may be added separately and mixed after preparing a mixed solution of two or more of the compounds A. For example, the (meth)acrylic (thio) acid ester compound is preferably mixed simultaneously with the compound A, and the photoradical polymerization initiator is preferably added separately and mixed after preparing a mixed solution of the compound A.

[0056] [Cured Product] The cured product of the present invention is a cured product obtained from the curable composition of the present invention, and is a cured product obtained from the curable composition of the present invention. ａ ~R ｈThe cured product of the present invention is obtained by curing a curable composition containing two or more monomers (compounds in which at least one of the groups is a (meth)acryloylthio)oxy group). The cured product of the present invention is obtained by proceeding with a polymerization reaction of a monomer containing the compound A and curing the monomer. The cured product of the present invention may contain unreacted monomers (e.g., the compound A, a (meth)acrylic (thio) acid ester compound), etc. As described above, the cured product of the present invention can exhibit a high refractive index.

[0057] The refractive index of the cured product of the present invention can be evaluated using the refractive index (nD) at 25°C and a wavelength of 589 nm (also simply referred to as "refractive index nD of the cured product" in the present invention). The refractive index nD of the cured product of the present invention can be 1.670 or more, and is preferably 1.700 or more. In the region where the refractive index nD of the cured product is 1.670 or more, 10% of the refractive index nD of the cured product can be evaluated. －３ When applied to optical components, differences in the high refractive index performance occur depending on the order of magnitude. There is no particular upper limit to the refractive index nD of the cured product of the present invention, and a practical value is 1.800 or less. The refractive index nD of the cured product is a value measured using an Abbe refractometer (for example, manufactured by Atago Co., Ltd., product name: Multi-wavelength Abbe refractometer DR-M2 or DR-M4). Specifically, a measurement sample (cured product) can be prepared and measured according to the description in the examples below. When forming the cured product, a heating step may be employed instead of the ultraviolet irradiation step described in the examples below, or both a heating step and an ultraviolet irradiation step may be employed. JIS B 7090:1999 Optics and optical instruments - Reference wavelengths (ISO 7944:1998 Optics and optical instruments - Reference wavelengths) can be referenced as appropriate.

[0058] The transmittance of the cured product of the present invention is preferably 85% or more, more preferably 90% or more, and even more preferably 95% or more over the entire visible light wavelength range of 360 to 830 nm. The upper limit of the transmittance of the cured product of the present invention is not particularly limited, but practically 99% or less. The transmittance of the cured product is the value of external transmittance, including surface reflection, measured for a 150 μm thick cured product using an ultraviolet-visible spectrophotometer (for example, UV-2600 (trade name), manufactured by Shimadzu Corporation).

[0059] The shape and thickness of the cured product of the present invention can be adjusted appropriately depending on the shape to which the cured product of the present invention is to be applied.

[0060] [Method for producing a cured product] The cured product of the present invention can be produced by a method including a step of photocuring the above-mentioned curable composition. When photocuring, it is preferable to contain the above-mentioned photoradical polymerization initiator in the curable composition. Regarding the photocuring conditions, the conditions for photopolymerization (photocuring) described below can be preferably applied.

[0061] In the method for producing a cured product of the present invention, it is preferable to photo-cure the curable composition of the present invention while pressing it against a mold, thereby obtaining a cured product to which the pattern of the mold has been transferred. From the viewpoint of releasability, the mold is preferably one that has been surface-treated with chromium nitride. As the surface treatment of the mold with chromium nitride, for example, the description of the chromium nitride treatment in paragraph

[0108] of WO 2019 / 044863 can be applied as is, except that "metal mold" is replaced with "mold".

[0062] FIG. 1 is a schematic cross-sectional view illustrating a method for producing a cured product of the present invention by imprinting technology using the curable composition of the present invention. The size, shape, and thickness of the substrate 3, the size, shape, transfer pattern, and thickness of the mold 5, and the amount of the curable composition 1 used can be appropriately adjusted so as to obtain a cured product 7 having the desired size, shape, transferred pattern, and thickness. As shown in FIG. 1 , (a) first, the curable composition 1 is sandwiched between the mold 5 and the substrate 3, (b) the curable composition 1 is pressed into the mold 5 while embossed, and the curable composition 1 is photocured by ultraviolet irradiation (UV irradiation), thereby producing a cured product 7 to which the pattern of the mold 5 has been transferred, and (c) the obtained cured product 7 and the substrate 3 are released (peeled) from the mold 5, thereby producing the cured product 7. The type of ultraviolet irradiation is not particularly limited as long as the curable composition 1 is cured, and may be irradiated from either the mold 5 or the substrate 3. It is preferable that the substrate 3 is transparent and that the irradiation is performed from the substrate 3 side. The obtained cured product 7 may be used in a form integrated with the substrate 3, or may be used in a form consisting of the cured product 7 after the substrate 3 is peeled off. The description of the transparent substrate in the diffractive optical element described below can be preferably applied to the substrate 3.

[0063] [Uses of Cured Product] The cured product of the present invention can be used in a variety of applications, and because it exhibits a high refractive index, it can be preferably used as an optical material. In particular, because the curable composition of the present invention used to obtain the cured product of the present invention exhibits excellent stability over time, cured products having microstructures with various patterns ranging in size from nanometers to several hundred micrometers can be produced using imprinting technology or the like, and can be preferably used for microlenses such as microlenses in micro OLED (Organic Light Emitting Diode) displays and microlenses for image sensors, diffractive optical elements (preferably diffractive optical elements for waveguides) in augmented reality glasses (AR glasses), and the like.

[0064] [Diffractive Optical Element] The diffractive optical element of the present invention comprises the cured product of the present invention, and is preferably a diffractive optical element comprising a surface having a diffraction grating pattern formed from the cured product of the present invention, and is formed by curing the curable composition of the present invention. The diffractive optical element of the present invention preferably has a maximum thickness of 0.05 μm to 100 μm. The maximum thickness is more preferably 0.1 μm to 50 μm, and even more preferably 0.2 μm to 30 μm. The step height (grating thickness) of the diffraction grating pattern (periodic structure) of the diffractive optical element is preferably 0.05 μm to 100 μm, more preferably 0.05 μm to 50 μm, and even more preferably 0.1 μm to 30 μm. The pitch of the diffraction grating pattern of the diffractive optical element may be between 0.05 μm and 1 mm, and is preferably between 0.05 μm and 100 μm, and preferably varies within the same diffractive optical element depending on the required optical aberration.

[0065] A diffractive optical element can be manufactured, for example, by the following procedure. A curable composition is sandwiched between a transparent substrate and a surface of a mold, such as a metal die, having a surface processed into a diffraction grating shape. The curable composition may then be pressurized and stretched to a desired extent. While sandwiched, the curable composition is irradiated with light from the transparent substrate side to cure. The cured product is then released from the mold, such as a metal die. After release, ultraviolet light may be irradiated from the side opposite the transparent substrate.

[0066] Examples of the transparent substrate include flat glass such as black kelvin glass, and flat transparent resins (e.g., (meth)acrylic resins, polycarbonate resins, and polyethylene terephthalate resins). The surface of the transparent substrate may be subjected to a surface treatment such as ozone treatment. The transparent substrate used in the above production may be included in the diffractive optical element as is, or may be peeled off.

[0067] The photopolymerization (photocuring) conditions are preferably as follows. The light used for irradiation to cure the curable composition is preferably ultraviolet light or visible light, and more preferably ultraviolet light. For example, a metal halide lamp, a low-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a germicidal lamp, a xenon lamp, an LED (Light Emitting Diode) light source lamp, or the like is preferably used. The illuminance of the ultraviolet light used for irradiation to cure the curable composition is 1 to 100 mW / cm. ２ is preferred, and 1 to 75 mW / cm ２ More preferably, 5 to 50 mW / cm ２ It is more preferable that the ultraviolet light be irradiated multiple times with different illuminances. The exposure dose of the ultraviolet light is 0.4 to 10 J / cm. ２ is preferred, and 0.5 to 5 J / cm ２ More preferably, 1 to 3 J / cm ２ The atmosphere during light irradiation is preferably air or an inert gas-substituted atmosphere, and more preferably an atmosphere in which air has been substituted with nitrogen until the oxygen concentration becomes 1% or less.

[0068] A diffraction grating pattern can be produced by using the curable composition of the present invention as an imprint material, pressing a mold (die) having a desired pattern of nanometers to several hundred micrometers into the material, photocuring to produce a cured product of the present invention to which the mold pattern has been transferred, and then releasing the mold. The photocuring conditions can be applied to the above-mentioned descriptions of the method for producing a cured product and the photopolymerization (photocuring) conditions. Other than the above, descriptions of commonly used imprints can be used without particular limitations. For example, see Nanoimprint Technology Handbook (edited by the Society of Applied Physics and Nanoimprint Technology Research Group, Ohmsha Publishing, December 1, 2019).

[0069] The present invention will be described in more detail below based on examples. The materials, amounts used, ratios, treatment details, treatment procedures, etc. shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be construed as being limited by the specific examples shown below. In the following, room temperature means 25°C unless otherwise specified. All steps from preparation of the curable composition to production of the cured product or evaluation tests were carried out in an environment using yellow light as illumination.

[0070] [Synthesis Example] Compound A and a comparative compound were synthesized as follows.

[0071] <Synthesis of Compound A> [Synthesis Example 1: Synthesis of Compound (A-4)]

[0072] While mixing 5.00 g (26.0 mmol) of 1,6-naphthalenedithiol and 60 mL of N,N-dimethylacetamide (DMAc), the mixture was cooled to an internal temperature (liquid temperature) of 0°C. 6.93 g (54.6 mmol) of 3-chloropropionyl chloride (3CPC) was added dropwise so that the liquid temperature did not exceed 7°C, and the mixture was heated to an internal temperature (liquid temperature) of 25°C. After stirring for 1 hour, the mixture was cooled to 0°C and triethylamine (Et ３ 11.05 g (109.2 mmol) of ethyl acetate (N) was added dropwise so that the liquid temperature did not exceed 7°C, and then the mixture was heated to an internal temperature (liquid temperature) of 25°C. After stirring for 1 hour, 150 mL of ethyl acetate and 150 mL of 1N hydrochloric acid were added, followed by washing and separation. Next, 80 mL of a 5% aqueous solution of sodium bicarbonate was added, followed by stirring, washing and separation. An oily composition was obtained by dehydration with magnesium sulfate, filtration, and concentration, and then purified by column chromatography using hexane and ethyl acetate to obtain 6.3 g of compound (A-4). Yield: 81%. Compound (A-4) １ H-NMR (300MHz, CDCl ３ ): δ (ppm) 5.8-5.9 (m, 2H), 6.3-6.6 (m, 4H), 7.6-7.7 (m, 2H), 7.78 (d, 1H), 7.96 (d, 1H), 8.05 (s, 1H), 8.21 (d, 1H)

[0073] Synthesis Example 2: Synthesis of Compound (A-8) Compound (A-8) described below was synthesized in the same manner as in Synthesis Example 1, except that 1,6-naphthalenedithiol was replaced with 2,7-naphthalenedithiol. Yield: 80%. Compound (A-8) １ H-NMR (300MHz, CDCl ３ ): δ (ppm) 5.8-5.9 (m, 2H), 6.3-6.6 (m, 4H), 7.5-7.6 (m, 2H), 7.92 (d, 2H), 7.98 (s, 2H)

[0074] [Synthesis Example 3: Synthesis of compound (A-9)]

[0075] While mixing 5.00 g (22.3 mmol) of 1,3,6-naphthalene trithiol and 75 mL of N,N-dimethylacetamide (DMAc), the mixture was cooled to an internal temperature (liquid temperature) of 0°C. 8.77 g (69.1 mmol) of 3-chloropropionyl chloride (3CPC) was added dropwise so that the liquid temperature did not exceed 7°C, and the mixture was heated to an internal temperature (liquid temperature) of 25°C. After stirring for 1 hour, the mixture was cooled to 0°C and triethylamine (Et ３ 13.98 g (138.2 mmol) of ethyl acetate (N) was added dropwise so that the liquid temperature did not exceed 7°C, and then the mixture was heated to an internal temperature (liquid temperature) of 25°C. After stirring for 1 hour, 150 mL of ethyl acetate and 150 mL of 1N hydrochloric acid were added, followed by washing and separation. Next, 80 mL of a 5% aqueous solution of sodium bicarbonate was added, followed by stirring, washing and separation. An oily composition was obtained by dehydration with magnesium sulfate, filtration, and concentration, and then purified by column chromatography using hexane and ethyl acetate to obtain 6.2 g of compound (A-9). Yield: 72%. Compound (A-9) １ H-NMR (300MHz, CDCl ３ ): δ (ppm) 5.8-5.9 (m, 3H), 6.3-6.6 (m, 6H), 7.6-7.7 (m, 1H), 7.80 (s, 1H), 8.01 (s, 1H), 8.07 (s, 1H), 8.20 (d, 1H)

[0076] Synthesis Example 4: Synthesis of compound (A-52)

[0077] While mixing 5.00 g (31.2 mmol) of 2-naphthalenethiol and 60 mL of N,N-dimethylacetamide (DMAc), the mixture was cooled to an internal temperature (liquid temperature) of 0°C. 4.16 g (32.8 mmol) of 3-chloropropionyl chloride (3CPC) was added dropwise so that the liquid temperature did not exceed 7°C, and the mixture was heated to an internal temperature (liquid temperature) of 25°C. After stirring for 1 hour, the mixture was cooled to 0°C and triethylamine (Et ３ 6.63 g (65.5 mmol) of ethyl acetate (N) was added dropwise so that the liquid temperature did not exceed 7°C, and then the mixture was heated to an internal temperature (liquid temperature) of 25°C. After stirring for 1 hour, 100 mL of ethyl acetate and 100 mL of 1N hydrochloric acid were added, followed by washing and separation. Next, 80 mL of a 5% aqueous solution of sodium bicarbonate was added, followed by stirring, washing and separation. An oily composition was obtained by dehydration with magnesium sulfate, filtration, and concentration, and then purified by column chromatography using hexane and ethyl acetate to obtain 5.5 g of compound (A-52). Yield: 83%. Compound (A-52) １ H-NMR (300MHz, CDCl ３ ): δ (ppm) 5.8-5.9 (m, 1H), 6.3-6.6 (m, 2H), 7.4-7.6 (m, 3H), 7.8-7.9 (m, 3H), 7.98 (s, 1H)

[0078] [Synthesis Example 5: Synthesis of Compound (A-17)] Compound (A-17) described below was synthesized based on the synthesis method for 16NDSHMA described in Example 2 of WO 2023 / 058449. Yield: 70% [Synthesis Example 6: Synthesis of Compound (A-21)] Compound (A-21) described below was synthesized based on the synthesis method for 27NDSHMA described in Comparative Example 2-3 of WO 2023 / 058449. Yield: 65%

[0079] Synthesis Example 7: Synthesis of compound (A-22)

[0080] Under a nitrogen atmosphere, 3.85 g (48.1 mmol) of 50% aqueous sodium hydroxide solution, 30 g of water, and 76 mg (2.0 mmol) of sodium borohydride were mixed. After adding 3 g (13.4 mmol) of 1,3,6-naphthalenetrithiol, the mixture was heated to 60°C and stirred for 20 minutes to obtain an aqueous solution containing the sodium salt of 1,3,6-naphthalenetrithiol. Next, a flask containing 30 mL of dichloromethane, 4.61 g (44.1 mmol) of methacryloyl chloride, and 8 mg of p-methoxyphenol was cooled to 0-5°C, and the aqueous solution containing the thiol-sodium salt was added dropwise. The mixture was stirred at 5°C for 1 hour to allow the reaction to proceed. The reaction solution was separated and the dichloromethane layer was extracted. Then, 30 mL of water and 30 mL of dichloromethane were added, followed by washing and separation. The mixture was then dehydrated using magnesium sulfate, filtered, and concentrated to obtain an oily concentrate. 30 mL of methanol was added to the concentrate, and the mixture was stirred at 5°C to precipitate crystals, which were then filtered under reduced pressure to obtain 3.6 g of compound (A-22). Yield: 63% Compound (A-22) １ H-NMR (300MHz, CDCl ３ ): δ (ppm) 2.03 (s, 9H), 5.73 (s, 3H), 6.26 (m, 3H), 7.5-7.6 (m, 1H), 7.80 (s, 1H), 8.01 (s, 1H), 8.07 (s, 1H), 8.20 (d, 1H),

[0081] Synthesis Example 8: Synthesis of compound (A-54)

[0082] Under a nitrogen atmosphere, 6.0 g (74.9 mmol) of 50% aqueous sodium hydroxide solution, 40 g of water, and 0.12 g (3.1 mmol) of sodium borohydride were mixed. Next, 10.0 g (62.4 mmol) of 2-naphthalenethiol was added, and the mixture was heated to 60°C and stirred for 20 minutes to obtain an aqueous solution containing the sodium salt of 2-naphthalenethiol. Next, a flask containing 50 mL of dichloromethane and 7.18 g (68.7 mmol) of methacryloyl chloride was cooled to 0-5°C, and the aqueous solution containing the thiol-sodium salt was added dropwise. The mixture was stirred at 5°C for 1 hour to allow the reaction to proceed. The reaction solution was separated and the dichloromethane layer was extracted. After that, 100 mL of water and 100 mL of dichloromethane were added, followed by washing and separation again. Subsequently, the mixture was dehydrated using magnesium sulfate, filtered, and concentrated to obtain an oily concentrate. 200 mL of methanol was added to the concentrate, and the mixture was stirred at 5°C to precipitate crystals, which were then filtered under reduced pressure to obtain 9.2 g of compound (A-54). Yield: 65% Compound (A-54) １ H-NMR (300MHz, CDCl ３ ): δ (ppm) 2.03 (s, 3H), 5.73 (s, 1H), 6.26 (m, 1H), 7.4-7.6 (m, 3H), 7.8-7.9 (m, 3H), 7.98 (s, 1H)

[0083] All of the compounds obtained in the above synthesis examples were crystalline.

[0084] <Synthesis of Comparative Compounds> [Synthesis of Comparative Compound 1: Synthesis of Comparative Compound (C-1)]

[0085] Comparative compound (C-1) was synthesized (yield 77%) in the same manner as in Synthesis Example 1, except that 1,6-naphthalenedithiol was replaced with 2,6-naphthalenedithiol. １ H-NMR (300MHz, CDCl ３ ): δ (ppm) 5.8-5.9 (m, 2H), 6.3-6.6 (m, 4H), 7.53 (d, 2H), 7.88 (d, 2H), 8.01 (s, 2H)

[0086] [Synthesis of Comparative Compound 2: Synthesis of Comparative Compound (C-2)] Comparative Compound (C-2) described below was synthesized based on the synthesis of 1,6-diacryloyloxynaphthalene described in Synthesis Example 4 of JP-A No. 2009-256633. [Synthesis of Comparative Compound 3: Synthesis of Comparative Compound (C-3)] Comparative Compound (C-3) described below was synthesized based on the synthesis of 2,7-diacryloyloxynaphthalene described in Synthesis Example 6 of JP-A No. 2009-256633.

[0087] The compound (A-30) used was 16DMNDSH (trade name) manufactured by Sugai Chemical Industry Co., Ltd. The naphthothiol raw material was also obtained from Sugai Chemical Industry Co., Ltd.

[0088] [Preparation of Curable Compositions] Compound A and / or a comparative compound as the main monomer and the diacrylic acid ester compound M-7 as another monomer were mixed to obtain the compositions shown in Tables 1-1 to 1-3 below (collectively referred to as "Table 1"), dissolved in ethyl acetate, and then concentrated at 60°C and a reduced pressure of 40 hPa until the ethyl acetate was completely removed. A photoradical polymerization initiator (referred to as "photopolymerization initiator" in Table 1) was added to the resulting concentrate, and the mixture was stirred while heating to 60°C to homogenize, thereby preparing a curable composition. Curable Compositions Nos. 101 to 112 are curable compositions of the present invention, and Curable Compositions Nos. c11 to c17 are curable compositions for comparison.

[0089] The refractive index and stability over time of the curable compositions were evaluated as follows. The results are shown in Table 1.

[0090] [Evaluation 1: Refractive Index Measurement] (1) Preparation of Cured Product The curable composition prepared above was sandwiched between hydrophobized glass plates so that the film thickness of the cured product would be 150 μm, and the cured product was irradiated with nitrogen (N ) using a UV irradiation device (EXECURE 3000 (trade name), manufactured by HOYA CANDEO OPTRONICS) to an oxygen concentration of 1% or less. ２ ) In a substituted atmosphere, the cumulative light dose was 1.2 J / cm ２ , illuminance 5mW / cm ２After irradiating with UV (ultraviolet rays) under the above conditions, the film was peeled off from the glass plate to prepare a cured product. The transmittance values ​​measured by the above-described measurement method for the 150 μm-thick cured products of curable compositions No. 101 to 112 prepared above were all 85% or higher over the entire visible light wavelength range of 360 to 830 nm. (2) Measurement of Refractive Index Using the cured products prepared under the above conditions, the refractive index at a wavelength of 589 nm (refractive index nD of the cured product) was measured at 25°C using a multi-wavelength Abbe refractometer DR-M2 or DR-M4 (trade name, manufactured by Atago Co., Ltd.), and evaluated according to the following criteria. - Evaluation criteria for refractive index nD of cured product - A: 1.700≦nD B: 1.670≦nD<1.700 C: 1.640≦nD<1.670 D: nD<1.640

[0091] [Evaluation 2: Liquid Stability Test] 5 mL of the curable composition prepared above was placed in a sample bottle with a diameter of 2.4 cm and a volume of 13 mL and stored at 25°C. The presence or absence of changes in crystal precipitation and / or turbidity over time was visually observed, and the liquid stability over time was evaluated according to the following criteria. Storage was performed under an environment using yellow light as illumination. - Evaluation Criteria for Liquid Stability Over Time - AA: No changes in crystal precipitation or turbidity occurred after storage at 25°C for 7 days (168 hours), and no changes in crystal precipitation or turbidity occurred after further storage at 0°C for 2 days (48 hours). A: No changes in crystal precipitation or turbidity occurred after storage at 25°C for 7 days (168 hours), but at least one of crystal precipitation and turbidity was observed during further storage at 0°C for 2 days (48 hours). B: At least one of crystal precipitation and turbidity was observed during storage at 25°C for 3 days or more (72 hours or more) but less than 7 days (less than 168 hours). C: At least one of crystal precipitation and turbidity was observed during storage at 25°C for 2 days or more (48 hours or more) but less than 3 days (less than 72 hours). D: At least one of crystal precipitation and turbidity was observed during storage at 25°C for 1 day or more (24 hours or more) but less than 2 days (less than 48 hours). E: At least one of crystal precipitation and turbidity was observed during storage at 25°C for less than 1 day (less than 24 hours). F: At least one of crystal precipitation and turbidity occurred within 2 hours after concentration was performed to prepare the curable composition.

[0092]

[0093] The wt% blending amount of each component listed in the Component column means % by mass. "-" indicates that the component is not contained. Furthermore, the component ratio listed in the Main Monomer column means the content ratio of each compound constituting the main monomer, and wt% means % by mass. If the main monomer is a mixture of two or more compounds, the content ratio of each compound is listed in the order of the compounds listed in the Type column. For example, in No. 103, the main monomer is composed of 33.4 wt% A-4, 33.3 wt% A-8, and 33.3 wt% A-21.

[0094] The components in the table are as follows: Main monomer: Compound A or a comparative compound shown below. In the structural formulas below, the point group is also shown below the number of each compound.

[0095] (Compound A)

[0096] (Comparative Compound)

[0097] Comparative compound (C-1) has a point group C ｓ But C ２ｖ The comparative compounds (C-2) and (C-3) are not compounds represented by the general formula (1), and therefore are not compounds A defined in the present invention.

[0098] (Other Monomers) M-7: The following diacrylic acid ester compound (1,4-butanediol diacrylate).

[0099] (Photopolymerization initiator) IrgTPO: Irgacure TPO (trade name, manufactured by BASF Japan Ltd., available as Omnirad TPO H (trade name, manufactured by IGM Resins B.V.)), diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide

[0100] The results in Table 1 reveal the following. Comparative curable compositions Nos. c11 and c12 are not curable compositions of the present invention in that they contain only one type of compound A. These comparative curable compositions Nos. c11 and c12 had poor stability over time of the composition (liquid). Note that, although the stability over time of the composition (liquid) can be improved by using a form containing one type of compound A and other monomers, as in comparative curable composition No. c13, the refractive index nD of the obtained cured product was low and therefore poor. In other words, it can be seen that a form containing only one type of compound A cannot achieve both excellent stability over time of the composition (liquid) and a high refractive index of the obtained cured product. Furthermore, comparative curable compositions Nos. c14 and c15 contain one type of compound A and a compound represented by general formula (1) but with a point group C ２ｈThese comparative curable compositions Nos. c14 and c15 were inferior in stability over time as compositions (liquids). Comparative curable compositions Nos. c16 and c17 were also different from the curable compositions of the present invention in that they contained one type of compound A and a comparative compound (C-1) having a point group of C. ｓ or C ２ｖ Although these compositions contain one of the comparative compounds (C-2) or (C-3), which are not compounds represented by general formula (1), they are not the curable compositions of the present invention. These comparative curable compositions Nos. c16 and c17 were inferior in the stability of the compositions (liquids) over time. In contrast, the curable compositions Nos. 101 to 112 of the present invention were excellent in the stability of the compositions (liquids) over time, and the obtained cured products all had high refractive indices nD of 1.700 or more, which were excellent. Furthermore, among the curable compositions Nos. 101, 102, and 110 to 112 containing two types of compound A, curable compositions Nos. 101, 102, 110, and 112, in which the content of each compound A is 10% by mass or more relative to 100% by mass of the total amount of compound A, exhibited superior stability of the compositions (liquids) over time, and further, all point groups (at least two point groups) of compound A were C ｓ Curable composition No. 112, which contained three or more compounds A, exhibited even better stability over time of the composition (liquid). Furthermore, curable compositions No. 103 to 109, which contained three or more compounds A, generally exhibited better stability over time of the composition (liquid) than curable compositions No. 101, 102, and 110 to 112, which contained two types of compounds A. Among curable compositions No. 103 to 109, which contained three or more compounds A, the point groups of at least two of the compounds A were C ｓ Curable compositions Nos. 104 to 108, which satisfy the conditions that the content of each compound A in 100% by mass of the total of compounds A is 10% by mass or more, exhibit even better stability over time of the composition (liquid), and all point groups of compound A are C ｓ and the content of each compound A in 100% by mass of the total amount of compound A was 10% by mass or more, the curable compositions Nos. 106 to 108 exhibited particularly excellent stability over time of the composition (liquid).

[0101] While the present invention has been described in connection with embodiments thereof, we do not intend to limit our invention to any of the details of the description unless otherwise specified, and believe that the claims should be construed broadly without departing from the spirit and scope of the invention as set forth in the appended claims.

[0102] This application claims priority based on Japanese Patent Application No. 2024-105755, filed in Japan on June 28, 2024, the contents of which are incorporated herein by reference.

[0103] REFERENCE SIGNS LIST 1 Curable composition 3 Substrate 5 Mold 7 Cured product

Claims

1. Represented by the following general formula (1) and the point group is C ｓ or C ２ｖ and at least one of the compounds A is ａ ~R ｈ A curable composition, wherein at least one of the above is a compound having a (meth)acryloylthioxy group. In the above formula, R ａ ~R ｈ represents a hydrogen atom, an alkylsulfanyl group having 1 to 10 carbon atoms, or a (meth)acryloylthioxy group. However, the above compound A does not include compounds represented by the following structural formula: In the above formula, R １ represents a hydrogen atom or a methyl group.

2. The curable composition according to claim 1, which contains three or more types of compound A.

3. At least two point groups of the compound A are C ｓ 2. The curable composition of claim 1, wherein 4. All point groups of the compound A are C ｓ The curable composition of claim 3, wherein 5. The curable composition according to claim 1, wherein the content of each compound A is 10% by mass or more relative to 100% by mass of the total amount of the compounds A.

6. The curable composition according to claim 1, which is for imprinting.

7. A cured product obtained from the curable composition according to any one of claims 1 to 6.

8. An optical material comprising the cured product according to claim 7.

9. A microlens or diffractive optical element comprising the cured product according to claim 7.

Images