Curable composition, cured product, molded article, optical material, and method for producing polyfunctional (meth)acrylic acid thioester composition

Abstract

[1] A polyfunctional (meth)acrylate thioester composition containing a polyfunctional (meth)acrylate thioester compound (A) represented by formula (1); [2] a curable composition containing the polyfunctional (meth)acrylate thioester composition according to [1]; [3] a cured product obtained by curing the curable composition according to [2]; [4] a molded body containing the cured product according to [3]; and [5] an optical material containing the molded body according to [4].

Description

[Technical Field]

[0001] The present invention relates to a polyfunctional (meth)acrylic acid thioester composition, a curable composition, a cured product, a molded article, an optical material, and a method for producing the polyfunctional (meth)acrylic acid thioester composition. [Background technology]

[0002] Glass has traditionally been used as an optical material due to its wide range of refractive indexes and its small variations in temperature and humidity. However, in recent years, cured resins have come to be used in response to demands for lighter weight and lower costs.

[0003] For example, camera lens modules mounted on smartphones are increasingly using wafer-level lenses to reduce their size and height. Wafer-level lenses require cured resins with a high refractive index and excellent heat resistance. Furthermore, so-called hybrid wafer-level lenses, in which a resin lens is formed on a glass substrate, require a low cure shrinkage rate when the composition is cured to prevent peeling between the glass substrate and the resin lens due to residual stress. As a method for obtaining a cured resin product with a higher refractive index, Patent Documents 1 and 2 report a method using a transparent material obtained by photocuring a composition containing thio(meth)acrylate or the like. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 98 / 24761 [Patent Document 2] Japanese Patent Application Publication No. 8-325337 Summary of the Invention [Problem to be solved by the invention]

[0005] However, although the cured resin products obtained by the methods described in Patent Documents 1 and 2 have a high refractive index, they have a large shrinkage rate when cured and have problems with adhesion to glass.

[0006] The present invention has been made in view of the above circumstances, and provides a polyfunctional (meth)acrylic acid thioester composition and a curable composition which can give a cured product having an improved performance balance of high refractive index, low cure shrinkage, and glass adhesion, as well as a cured product, molded article, and optical material having an improved performance balance of high refractive index, low cure shrinkage, and glass adhesion. [Means for solving the problem]

[0007] The present inventors have conducted extensive research to solve the above problems, and as a result have found that the use of a specific polyfunctional (meth)acrylic acid thioester compound can improve the balance of the performance of the resulting cured product, including a high refractive index, low cure shrinkage, and glass adhesion, and have completed the present invention. According to the present invention, there are provided a polyfunctional (meth)acrylic acid thioester composition, a curable composition, a cured product, a molded article, an optical material, and a method for producing a polyfunctional (meth)acrylic acid thioester composition, which are shown below.

[0008] [1] A polyfunctional (meth)acrylic acid thioester composition comprising a polyfunctional (meth)acrylic acid thioester compound (A) represented by the following formula (1): [ka] (In the formula (1), n ​​is an integer of 5 or more, X represents an alkylene group having 1 to 4 carbon atoms in which any methylene group may be substituted with a carbonyl group, any hydrogen atom in the alkylene group is substituted with a structure of the following formula (2), and R1 and R2 each independently represent a hydrogen atom or a methyl group.) [ka] (In the formula (2), R3 represents a hydrogen atom or a methyl group, and multiple R3s may be the same or different, W represents an alkylene group having 1 to 4 carbon atoms, and o is an integer of 1 or more.) [2] The polyfunctional (meth)acrylic acid thioester composition according to [1] above, wherein the weight average molecular weight of the polyfunctional (meth)acrylic acid thioester composition is 1,000 or more and 100,000 or less. [3] The polyfunctional (meth)acrylic acid thioester composition according to [1] or [2], wherein the polyfunctional (meth)acrylic acid thioester compound (A) comprises at least one selected from the group consisting of a compound represented by the following formula (3) and a compound represented by the following formula (4): [ka] [ka] (In the formulas (3) and (4), m and n each independently represent an integer of 2 or more, X and Y each independently represent an alkylene group having 1 to 4 carbon atoms in which any hydrogen atom may be substituted with the structure of the formula (2), multiple Xs and Ys may be the same or different, and R1 and R2 each independently represent a hydrogen atom or a methyl group.) [4] A curable composition comprising the polyfunctional (meth)acrylic acid thioester composition according to any one of [1] to [3] above. [5] The curable composition according to [4] above, further comprising a compound (B) represented by the following formula (5): [ka] (In the formula (5), Z1 and Z2 each independently represent an aromatic carbon ring or an alkylene group, an arbitrary hydrogen atom may be substituted with an alkyl group or an alkoxy group, Z3 and Z4 each independently represent an aromatic carbon ring or an alkyl group, an arbitrary hydrogen atom may be substituted with an alkyl group or an alkoxy group, R1 and R3 each independently represent an alkylene group having 1 or more and 10 or less carbon atoms, R2 and R4 each independently represent a hydrogen atom or a methyl group, R5 and R6 each independently represent an alkyl group, m and n each independently represent an integer of 0 or more, and o, p, q, and r are each integers of 0 or more satisfying the relationship of o + q ≤ 4 and p + r ≤ 4.) [6] The curable composition according to [4] or [5], wherein the viscosity of the curable composition at 25 ° C. measured using an E-type viscometer under the condition of a rotation speed of 2.5 rpm is 100 mPa·s or more and 10,000 mPa·s or less. [7] The curable composition according to any one of [4] to [6], further comprising a polymerization initiator. [8] The curable composition according to any one of [4] to [7], further comprising at least one selected from the group consisting of a silane coupling agent, an antioxidant, an ultraviolet absorber, and a light stabilizer. [9] The specific gravity of the curable composition measured using a pycnometer in accordance with JIS Z 8804:2012 is d 1 and the specific gravity of a test piece with a thickness of 250 μm made of the cured product of the curable composition is d 2 When it is, (1 - d 1 / d 2 ) × 100, the curable composition according to any one of [4] to [8], wherein the curing shrinkage rate of the curable composition is 9.0% or less.

[10] The curable composition according to any one of [4] to [9], which can be used for an optical material.

[11] A cured product obtained by curing the curable composition according to any one of [4] to

[10] .

[12] The cured product according to

[11] above, wherein when a test piece having a thickness of 250 μm is prepared from the cured product, the test piece has a light transmittance (T1) of 81% or more at a wavelength of 400 nm.

[13] The cured product according to

[12] above, wherein the test piece is heated in an oven set at 125°C in an air atmosphere for 168 hours, and when the light transmittance of the test piece at a wavelength of 400 nm after the heat treatment is T2, the rate of change in light transmittance after heating, expressed as (T1-T2) / T1×100, is 7.0% or less.

[14] The cured product according to any one of

[11] to

[13] above, wherein when a test piece having a thickness of 250 μm is prepared from the cured product, the refractive index (nD) of the test piece at D line (589.3 nm) is 1.600 or more.

[15] The cured product according to any one of

[11] to

[14] above, wherein when a test piece having a thickness of 250 μm is prepared from the cured product, the Abbe number (νD) of the test piece measured in accordance with ASTM D542 is 20 or more.

[16] A molded article comprising the cured product according to any one of the above

[11] to

[15] .

[17] An optical material comprising the molded article according to

[16] above.

[18] further comprising a glass substrate; The optical material according to

[17] above, which is a laminate of the molded body and the glass substrate.

[19] The optical material according to

[17] or

[18] above, which is an optical lens.

[20] The method for producing the polyfunctional (meth)acrylic acid thioester composition according to any one of the above [1] to [3], includes a step of converting 0.5 equivalents or more and 0.9 equivalents or less of all thiol groups in a polythiol compound into a functional group represented by the following structural formula, and then subjecting the resulting compound to a β-elimination reaction and an enethiol reaction, thereby synthesizing a polyfunctional (meth)acrylic acid thioester compound. [ka] (In the structural formula, X represents a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom, and R represents a hydrogen atom or a methyl group.) [twenty one] A method for producing the polyfunctional (meth)acrylic acid thioester composition according to any one of the above [1] to [3], comprising a step of reacting a polythiol compound with a polythio(meth)acrylate compound by an enethiol reaction. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a polyfunctional (meth)acrylic acid thioester composition and a curable composition which can give a cured product having an improved performance balance of high refractive index, low cure shrinkage, and glass adhesion, as well as a cured product, molded article, and optical material having an improved performance balance of high refractive index, low cure shrinkage, and glass adhesion. DETAILED DESCRIPTION OF THE INVENTION

[0010] The present invention will be described below based on embodiments. In this specification, "A to B" indicating a numerical range means A or more and B or less unless otherwise specified. In addition, the term "(meth)acrylic" in this specification refers to at least one selected from the group consisting of acrylic and methacrylic, and the same applies to similar terms such as "thio(meth)acrylate" and "(meth)acrylate." In addition, in this specification, the term "(meth)acrylic group" refers to at least one selected from the group consisting of an acryloyl group represented by -C(=O)-CH=CH2 and a methacryloyl group represented by -C(=O)-C(CH3)=CH2.

[0011] [Polyfunctional (meth)acrylic acid thioester composition] The polyfunctional (meth)acrylic acid thioester composition of the present invention contains a polyfunctional (meth)acrylic acid thioester compound (A) (hereinafter, also simply referred to as "compound (A)") represented by the following formula (1). The polyfunctional (meth)acrylic acid thioester composition of the present invention may contain only one type of polyfunctional (meth)acrylic acid thioester compound (A), or may contain two or more types of polyfunctional (meth)acrylic acid thioester compounds (A). Note that even when the polyfunctional (meth)acrylic acid thioester composition of the present invention contains only one type of polyfunctional (meth)acrylic acid thioester compound (A), it is still referred to as a polyfunctional (meth)acrylic acid thioester composition.

[0012] [ka] In the formula (1), n ​​is an integer of 5 or more, X represents an alkylene group having 1 to 4 carbon atoms in which any methylene group may be substituted with a carbonyl group, any hydrogen atom in the alkylene group is substituted with a structure of the following formula (2), and R1 and R2 each independently represent a hydrogen atom or a methyl group.

[0013] [ka] In the formula (2), R3 represents a hydrogen atom or a methyl group, and multiple R3s may be the same or different, W represents an alkylene group having 1 to 4 carbon atoms, and o is an integer of 1 or more.

[0014] In the formula (1), n ​​is an integer of 5 or more, preferably an integer of 6 or more, more preferably an integer of 7 or more, and is preferably an integer of 20 or less, more preferably an integer of 15 or less, even more preferably an integer of 12 or less, and even more preferably an integer of 10 or less. In the formula (1), X represents an alkylene group having 1 to 4 carbon atoms, more preferably an alkylene group having 2 to 4 carbon atoms, and even more preferably an alkylene group having 2 to 3 carbon atoms, in which any methylene group may be substituted with a carbonyl group, and any hydrogen atom in the alkylene group is substituted with the structure of the formula (2). In the formula (1), the number of alkylene groups substituted with the structure of the formula (2) in X is preferably 1 or more and 4 or less, more preferably 1 or more and 3 or less, even more preferably 1 or 2, and still more preferably 2. In the formula (1), the number of carbonyl groups in X is preferably 1 or more and 4 or less, more preferably 1 or more and 3 or less, and even more preferably 1 or 2.

[0015] In the formula (2), W is an alkylene group having from 1 to 4 carbon atoms, preferably an alkylene group having from 1 to 3 carbon atoms, more preferably an alkylene group having 1 or 2 carbon atoms, and even more preferably an alkylene group having 1 carbon atom; o is an integer of 1 or more, preferably an integer of 1 to 4, more preferably an integer of 1 to 3, even more preferably 1 or 2, and even more preferably 1.

[0016] From the viewpoint of further improving the balance of the performance of the resulting cured product, which includes a high refractive index, low cure shrinkage, and glass adhesion, it is preferable that compound (A) contains at least one compound selected from the group consisting of compounds represented by the following formula (3) and compounds represented by the following formula (4):

[0017] [ka]

[0018] [ka] In the formulas (3) and (4), m and n each independently represent an integer of 2 or more, X and Y each independently represent an alkylene group having 1 to 4 carbon atoms in which any hydrogen atom may be substituted with the structure of the formula (2), multiple Xs and Ys may be the same or different, and R1 and R2 each independently represent a hydrogen atom or a methyl group.

[0019] In the formulas (3) and (4), m and n each independently represent an integer of 2 or more, preferably an integer of 2 or more and 6 or less, more preferably an integer of 2 or more and 5 or less, even more preferably an integer of 2 or more and 3 or less, and even more preferably 3. In the formulas (3) and (4), X and Y each independently represent an alkylene group having 2 to 4 carbon atoms in which any hydrogen atom may be substituted with the structure of the formula (2), preferably an alkylene group having 2 to 3 carbon atoms in which any hydrogen atom may be substituted with the structure of the formula (2), and more preferably an alkylene group having 2 carbon atoms in which any hydrogen atom may be substituted with the structure of the formula (2). In the formulas (3) and (4), the number of alkylene groups substituted with the structure of the formula (2) in X and Y is preferably 1 or more and 4 or less, more preferably 1 or more and 3 or less, even more preferably 1 or 2, and still more preferably 2.

[0020] From the viewpoint of further improving the performance balance of high refractive index, low cure shrinkage, and glass adhesiveness of the resulting cured product, it is more preferable that the compound (A) contains at least one selected from the group consisting of the following compounds:

[0021] [ka]

[0022] The weight-average molecular weight of the polyfunctional (meth)acrylic acid thioester composition according to the present invention is preferably 1,000 or more, more preferably 1,500 or more, and is preferably 100,000 or less, more preferably 50,000 or less, even more preferably 20,000 or less, even more preferably 10,000 or less, and even more preferably 5,000 or less, from the viewpoint of further improving the performance balance of high refractive index, low cure shrinkage, and glass adhesiveness of the resulting cured product.

[0023] The content of the compound (A) in the polyfunctional (meth)acrylic acid thioester composition according to the present invention, when the entire polyfunctional (meth)acrylic acid thioester composition is taken as 100% by mass, is preferably 70% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, still more preferably 95% by mass or more, and preferably 100% by mass or less, from the viewpoint of further improving the performance balance of high refractive index, low cure shrinkage, and glass adhesiveness of the resulting cured product.

[0024] (Method of producing polyfunctional (meth)acrylic acid thioester composition) The polyfunctional (meth)acrylic acid thioester composition according to the present invention can be produced, for example, by a production method including the steps of converting 0.5 equivalents to 0.9 equivalents of all thiol groups in a polythiol compound into a functional group represented by the following structural formula, and then subjecting the resulting compound to a β-elimination reaction and an enethiol reaction, thereby synthesizing a polyfunctional (meth)acrylic acid thioester compound. More specifically, as in Synthesis Example 3 described below, the thiol groups in the polythiol compound can be converted to functional groups represented by the following structural formula by reacting the polythiol compound with a halogenated alkylcarbonyl halide compound such as 3-chloropropionyl chloride. The β-elimination reaction and enethiol reaction can be carried out by known methods.

[0025] [ka] In the structural formula, X represents a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom, and preferably represents a chlorine atom, and R represents a hydrogen atom or a methyl group.

[0026] Furthermore, the polyfunctional (meth)acrylic acid thioester composition according to the present invention can also be produced, for example, by a production method including a step of reacting a polythiol compound with a polythio(meth)acrylate compound by an enethiol reaction. More specifically, a polyfunctional (meth)acrylic acid thioester composition can be obtained by reacting a polythio(meth)acrylate compound with a polythiol compound through an enethiol reaction, as in the later-described Synthesis Example 2. The enethiol reaction can be carried out by a known method.

[0027] [Curable composition] The curable composition according to the present invention contains the polyfunctional (meth)acrylic acid thioester composition according to the present invention described above. The curable composition according to the present invention can provide a cured product, a molded article, and an optical material that have an improved balance of high refractive index, low cure shrinkage, and glass adhesion.

[0028] Each component constituting the curable composition according to the present invention will be described below.

[0029] <Polyfunctional (meth)acrylic acid thioester composition> The polyfunctional (meth)acrylic acid thioester composition is the polyfunctional (meth)acrylic acid thioester composition according to the present invention described above. From the viewpoint of further improving the performance balance of high refractive index, low cure shrinkage, and glass adhesiveness of the obtained cured product, the content of the polyfunctional (meth)acrylic acid thioester composition in the curable composition according to the present invention is preferably 30 parts by mass or more, more preferably 40 parts by mass or more, even more preferably 50 parts by mass or more, even more preferably 70 parts by mass or more, even more preferably 80 parts by mass or more, and even more preferably 90 parts by mass or more, and is preferably 100 parts by mass or less, more preferably 99 parts by mass or less, relative to 100 parts by mass of the curable composition according to the present invention.

[0030] <Compound (B)> The curable composition according to the present invention may further contain a compound (B) represented by the following formula (5) (hereinafter also simply referred to as "compound (B)") from the viewpoint of further reducing the Abbe number and further improving the transparency, heat resistance, and post-heat stability.

[0031] [ka] In the formula (5), Z1 and Z2 each independently represent an aromatic carbon ring or an alkylene group, and any hydrogen atom may be substituted with an alkyl group or an alkoxy group; Z3 and Z4 each independently represent an aromatic carbon ring or an alkyl group, and any hydrogen atom may be substituted with an alkyl group or an alkoxy group; R1 and R3 each independently represent an alkylene group having 1 to 10 carbon atoms; R2 and R4 each independently represent a hydrogen atom or a methyl group; R5 and R6 each independently represent an alkyl group; m and n each independently represent an integer of 0 or greater; and o, p, q, and r each represent an integer of 0 or greater that satisfies the relationships o+q≦4, p+r≦4.

[0032] In the formula (5), Z1 and Z2 each independently represent an aromatic carbon ring or an alkylene group, and any hydrogen atom may be substituted with an alkyl group or an alkoxy group. Z1 and Z2 each independently represent preferably a benzene ring, a naphthalene ring, or an alkylene group having 1 to 4 carbon atoms, more preferably a benzene ring or an alkylene group having 1 to 3 carbon atoms. In the formula (5), Z3 and Z4 each independently represent an aromatic carbocyclic ring or an alkyl group, and any hydrogen atom may be substituted with an alkyl group or an alkoxy group. Z3 and Z4 each independently represent preferably an aromatic carbocyclic ring, more preferably a benzene ring or a naphthalene ring, and even more preferably a naphthalene ring. In the formula (5), R1 and R3 each independently represent an alkylene group having from 1 to 10 carbon atoms. R1 and R3 each independently represent an alkylene group having from 1 to 4 carbon atoms, more preferably an alkylene group having from 1 to 3 carbon atoms, even more preferably an alkylene group having from 2 to 3 carbon atoms, and even more preferably an alkylene group having 2 carbon atoms. In the formula (5), R2 and R4 each independently represent a hydrogen atom or a methyl group, and are preferably each independently a hydrogen atom. In the formula (5), R5 and R6 each independently represent an alkyl group, preferably an alkyl group having 1 to 4 carbon atoms, more preferably an alkyl group having 1 or 2 carbon atoms, and even more preferably an alkyl group having 1 carbon atom. In the formula (5), m and n each independently represent an integer of equal to or greater than 0. m and n each independently represent an integer of equal to or greater than 0 and equal to or less than 4, more preferably an integer of equal to or greater than 0 and equal to or less than 2, even more preferably 0 or 1, and even more preferably 1. In the formula (5), o, p, q, and r are each an integer of 0 or more that satisfies the relationships o+q≦4 and p+r≦4. q and r are each independently an integer of 0 or more and 2 or less, more preferably 0 or 1, and even more preferably 0. o and p are each independently an integer of 0 or more and 2 or less, more preferably 0 or 1, and even more preferably 0. From the viewpoint of further improving the performance balance of high refractive index, low cure shrinkage, and glass adhesiveness of the obtained cured product, compound (B) is preferably a compound represented by formula (5) in which Z1 and Z2 are benzene rings, naphthalene rings, or alkylene groups having 1 to 4 carbon atoms, Z3 and Z4 are benzene rings or naphthalene rings, R1 and R3 are alkylene groups having 1 to 4 carbon atoms, R2 and R4 are hydrogen atoms or methyl groups, m and n are integers of 0 to 4, q and r are 0 or 1, and o and p are 0, and more preferably a compound represented by formula (5) in which Z1 and Z2 are benzene rings or alkylene groups having 1 to 3 carbon atoms, Z3 and Z4 are naphthalene rings, R1 and R3 are alkylene groups having 1 to 3 carbon atoms, R2 and R4 are hydrogen atoms or methyl groups, m and n are 0 or 1, q and r are 0 or 1, and o and p are 0.

[0033] From the viewpoint of further improving the balance of the performance of the resulting cured product, which includes a high refractive index, low cure shrinkage, and glass adhesion, the compound (B) may be 9,9-bis(4-(meth)acryloyloxyphenyl)fluorene, 9,9-bis(4-(2-(meth)acryloyloxyethoxy)phenyl)fluorene, 9,9-bis(4-(3-(meth)acryloyloxypropoxy)phenyl)fluorene, 9,9-bis(4-(2-(meth)acryloyloxypropoxy)phenyl)fluorene, 9,9-bis(4-(meth)acryloyloxy-3-methylphenyl)fluorene, )fluorene, 9,9-bis[4-(2-(meth)acryloyloxyethoxy)-3-methylphenyl]fluorene, 9,9-bis[4-(3-(meth)acryloyloxypropoxy)-3-methylphenyl]fluorene, 9,9-bis[4-(2-(meth)acryloyloxypropoxy)-3-methylphenyl]fluorene, 9,9-bis[4-(2-(meth)acryloyloxypropoxy)-3-methylphenyl]fluorene, 9,9-bis(4-(meth)acryloyloxy-3-ethylphenyl)fluorene, 9,9-bis[4-(2-(meth)acryloyloxyethoxy)-3-ethylphenyl]fluorene, 9,9-bis[4-(3- (meth)acryloyloxypropoxy)-3-ethylphenyl]fluorene, 9,9-bis[4-(2-(meth)acryloyloxypropoxy)-3-ethylphenyl]fluorene, 9,9-bis(2-(meth)acryloyloxyethyl)-1,8-diphenylfluorene, 9,9-bis(3-(meth)acryloyloxypropyl)-1,8-diphenylfluorene, 9,9-bis(2-(meth)acryloyloxypropyl)-1,8-diphenylfluorene, 9,9-bis(2-(meth)acryloyloxyethyl)-2,7-diphenyl Fluorene, 9,9-bis(3-(meth)acryloyloxypropyl)-2,7-diphenylfluorene, 9,9-bis(2-(meth)acryloyloxypropyl)-2,7-diphenylfluorene, 9,9-bis(2-(meth)acryloyloxyethyl)-3,6-diphenylfluorene, 9,9-bis(3-(meth)acryloyloxypropyl)-3,6-diphenylfluorene, 9,9-bis(2-(meth)acryloyloxypropyl)-3,6-diphenylfluorene, 9,9-bis(2-(meth)acryloyloxyethyl)-4,5-diphenylfluorene, 9,9-bis(3-(meth)acryloyloxypropyl)-4,5-diphenylfluorene, 9,9-bis(2-(meth)acryloyloxypropyl)-4,5-diphenylfluorene, 9,9-bis(2-(meth)acryloyloxyethyl)-1,8-bis(naphth-1-yl)fluorene, 9,9-bis(3-(meth)acryloyloxypropyl)-1,8-bis(naphth-1-yl)fluorene, 9,9-bis(2-(meth)acryloyloxypropyl)-1,8-bis(naphth-1-yl)fluorene, 9,9-bis(2-(meth)acryloyloxyethyl)-2,7-bis(naphth-1-yl)fluorene, 9,9-bis(3-(meth)acryloyloxypropyl)-2,7-bis(naphth-1-yl)fluorene, 9,9-bis(2-(meth)acryloyloxypropyl)-2,7-bis(naphth-1-yl)fluorene, 9,9-bis(2-(meth)acryloyloxyethyl)-3,6-bis(naphth-1-yl)fluorene, 9,9-bis(3-(meth)acryloyloxypropyl)-3,6-bis(naphth-1-yl)fluorene, 9 ,9-bis(2-(meth)acryloyloxypropyl)-3,6-bis(naphth-1-yl)fluorene, 9,9-bis(2-(meth)acryloyloxyethyl)-4,5-bis(naphth-1-yl)fluorene, 9,9-bis(3-(meth)acryloyloxypropyl)-4,5-bis(naphth-1-yl)fluorene, 9,9-bis(2-(meth)acryloyloxypropyl)-4,5-bis(naphth-1-yl)fluorene, 9,9-bis(2-(meth)acryloyloxyethyl)-1,8-bis(naphth-2-yl)fluorene, 9, 9-bis(3-(meth)acryloyloxypropyl)-1,8-bis(naphth-2-yl)fluorene, 9,9-bis(2-(meth)acryloyloxypropyl)-1,8-bis(naphth-2-yl)fluorene, 9,9-bis(2-(meth)acryloyloxyethyl)-2,7-bis(naphth-2-yl)fluorene, 9,9-bis(3-(meth)acryloyloxypropyl)-2,7-bis(naphth-2-yl)fluorene, 9,9-bis(2-(meth)acryloyloxypropyl)-2,7-bis(naphth-2-yl)fluorene, 9,9-bis(2-(meth)acryloyloxyethyl)-3,6-bis(naphth-2-yl)fluorene, 9,9-bis(3-(meth)acryloyloxypropyl)-3,6-bis(naphth-2-yl)fluorene, 9,9-bis(2-(meth)acryloyloxypropyl)-3,6-bis(naphth-2-yl)fluorene, 9,9-bis(2-(meth)acryloyloxyethyl)-4,5-bis(naphth-2-yl)fluorene, 9,9-bis(3-(meth)acryloyloxypropyl)-4,5-bis(naphth-2-yl)fluorene, and and 9,9-bis(2-(meth)acryloyloxypropyl)-4,5-bis(naphth-2-yl)fluorene, more preferably 9,9-bis(4-(meth)acryloyloxyphenyl)fluorene, 9,9-bis(4-(2-(meth)acryloyloxyethoxy)phenyl)fluorene, 9,9-bis(4-(3-(meth)acryloyloxypropoxy)phenyl)fluorene, 9,9-bis(4-(2-(meth)acryloyloxypropoxy)phenyl)fluorene, 9,9-bis(2-( 9,9-bis(3-(meth)acryloyloxypropyl)-2,7-diphenylfluorene, 9,9-bis(2-(meth)acryloyloxypropyl)-2,7-diphenylfluorene, 9,9-bis(2-(meth)acryloyloxyethyl)-3,6-diphenylfluorene, 9,9-bis(3-(meth)acryloyloxypropyl)-3,6-diphenylfluorene, 9,9-bis(2-(meth)acryloyloxypropyl)-3,6-diphenylfluorene, 9, 9-bis(2-(meth)acryloyloxyethyl)-2,7-bis(naphth-1-yl)fluorene, 9,9-bis(3-(meth)acryloyloxypropyl)-2,7-bis(naphth-1-yl)fluorene, 9,9-bis(2-(meth)acryloyloxypropyl)-2,7-bis(naphth-1-yl)fluorene, 9,9-bis(2-(meth)acryloyloxyethyl)-3,6-bis(naphth-1-yl)fluorene, 9,9-bis(3-(meth)acryloyloxypropyl)-3,6-bis(naphth-1-yl)fluorene, 9,9-bis(2-(meth)acryloyloxypropyl)-3,6-bis(naphth-1-yl)fluorene, 9,9-bis(2-(meth)acryloyloxyethyl)-2,7-bis(naphth-2-yl)fluorene, 9,9-bis(3-(meth)acryloyloxypropyl)-2,7-bis(naphth-2-yl)fluorene, 9,9-bis(2-(meth)acryloyloxypropyl)-2,7-bis(naphth-2-yl)fluorene, 9,9-bis(2-(meth)acryloyloxyethyl)-3,6-bis(naphth-2-yl)fluorene, 9,9- At least one selected from the group consisting of bis(3-(meth)acryloyloxypropyl)-3,6-bis(naphth-2-yl)fluorene and 9,9-bis(2-(meth)acryloyloxypropyl)-3,6-bis(naphth-2-yl)fluorene is more preferred, and 9,9-bis(4-(2-(meth)acryloyloxyethoxy)phenyl)fluorene, 9,9-bis(4-(3-(meth)acryloyloxypropoxy)phenyl)fluorene, 9,9-bis(4-(2-(meth)acryloyloxypropoxy)phenyl)fluorene, fluorene, 9,9-bis(2-(meth)acryloyloxyethyl)-2,7-bis(naphth-1-yl)fluorene, 9,9-bis(3-(meth)acryloyloxypropyl)-2,7-bis(naphth-1-yl)fluorene, 9,9-bis(2-(meth)acryloyloxypropyl)-2,7-bis(naphth-1-yl)fluorene, 9,9-bis(2-(meth)acryloyloxyethyl)-3,6-bis(naphth-1-yl)fluorene, 9,9-bis(3-(meth)acryloyloxypropyl)-3,6-bis(naphth-1-yl)fluorene, 9,9-bis(2-(meth)acryloyloxypropyl)-3,6-bis(naphth-1-yl)fluorene, 9,9-bis(2-(meth)acryloyloxyethyl)-2,7-bis(naphth-2-yl)fluorene, 9,9-bis(3-(meth)acryloyloxypropyl)-2,7-bis(naphth-2-yl)fluorene, 9,9-bis(2-(meth)acryloyloxypropyl)-2,7-bis(naphth-2-yl)fluorene, 9,9-bis(2-(meth)acryloyloxyethyl)-3,6-bis(naphth-2-yl)fluorene, 9,At least one selected from the group consisting of 9-bis(3-(meth)acryloyloxypropyl)-3,6-bis(naphth-2-yl)fluorene and 9,9-bis(2-(meth)acryloyloxypropyl)-3,6-bis(naphth-2-yl)fluorene.

[0034] The content of compound (B) in the curable composition according to the present invention is, from the viewpoint of further improving the performance balance of a high refractive index, a low Abbe number, a low cure shrinkage, and glass adhesion of the obtained cured product, and from the viewpoint of further improving the transparency, heat resistance, and post-heating stability, preferably 1 part by mass or more, more preferably 5 parts by mass or more, even more preferably 10 parts by mass or more, even more preferably 15 parts by mass or more, and even more preferably 20 parts by mass or more, and is preferably 70 parts by mass or less, more preferably 60 parts by mass or less, and even more preferably 50 parts by mass or less, relative to 100 parts by mass of the curable composition according to the present invention.

[0035] (Method for synthesizing compound (B)) Examples of commercially available products of compound (B) include the bifunctional acrylate "A-BPEF" manufactured by Shin-Nakamura Scientific Industrial Co., Ltd., and the bifunctional acrylates "OGSOL EA-0200" and "OGSOL EA-0300" manufactured by Osaka Gas Chemicals Co., Ltd. Furthermore, the compound (B) can be synthesized by (meth)acryloyl esterifying a commercially available fluorene derivative diol using (meth)acrylic anhydride, (meth)acryloyl chloride, or the like. Examples of commercially available fluorene derivative diols include BPEF (bisphenoxyethanol fluorene) and BPF (bisphenol fluorene) manufactured by Osaka Gas Chemicals Co., Ltd. Also, 9,9-bis(2-(meth)acryloyloxyethyl)-2,7-bis(naphth-2-yl)fluorene (DNEOA) can be synthesized by the following synthesis scheme.

[0036] [ka]

[0037] From the viewpoint of further improving the performance balance of high refractive index, low cure shrinkage, and glass adhesion of the obtained cured product, the viscosity of the curable composition according to the present invention at 25°C, measured using an E-type viscometer at a rotation speed of 2.5 rpm, is preferably 100 mPa·s or more, more preferably 500 mPa·s or more, even more preferably 1000 mPa·s or more, and still more preferably 1500 mPa·s or more, and is preferably 10000 mPa·s or less, more preferably 8000 mPa·s or less, even more preferably 6500 mPa·s or less, even more preferably 5000 mPa·s or less, and still more preferably 3500 mPa·s or less.

[0038] <Other ingredients> The curable composition of the present invention may contain other components in addition to the polyfunctional (meth)acrylic acid thioester composition and compound (B). Examples of such other components include polymerization initiators, ultraviolet absorbers, resin modifiers, internal mold release agents, silane coupling agents, antioxidants, light stabilizers, processing stabilizers, bluing agents, polymerized metal deactivators, flame retardants, lubricants, antistatic agents, heat shielding agents, fluorescent dyes (including fluorescent brighteners), pigments, light scattering agents, reinforcing fillers, surfactants, antibacterial agents, plasticizers, compatibilizers, other resins, and elastomers. Among these, the curable composition of the present invention preferably contains a polymerization initiator from the viewpoint of further improving curability. Furthermore, the curable composition of the present invention preferably further contains at least one selected from the group consisting of silane coupling agents, antioxidants, ultraviolet absorbers, and light stabilizers.

[0039] The curable composition according to the present invention preferably contains a polymerization initiator from the viewpoint of further improving the balance of the performance of the resulting cured product, including a high refractive index, low cure shrinkage, and glass adhesion. Examples of the polymerization initiator include a thermal radical polymerization initiator, a photoradical polymerization initiator, and a combination of these. Examples of thermal radical polymerization initiators include dialkyl peroxides such as dicumyl peroxide, t-butylcumyl peroxide, 2,5-bis(t-butylperoxy)2,5-dimethylhexane, 2,5-bis(t-butylperoxy)2,5-dimethylhexyne-3, di-t-butyl peroxide, isopropylcumyl-t-butyl peroxide, and bis(α-t-butylperoxyisopropyl)benzene; 1,1-bis(t-butylperoxy)cyclohexane, 1,1-bis(t-butylperoxy)3,3,5-trimethylcyclohexane, 1,1-bis(t-butylperoxy)cyclododecane, n-butyl-4,4-bis(t-butylperoxy)valerate, and ethyl-3,3-bis(t-butylperoxy). peroxyketals such as bis(t-butylperoxy)isophthalate, t-butylperoxybenzoate, t-butylperoxyacetate, and the like; hydroperoxides such as t-butyl hydroperoxide, t-hexyl hydroperoxide, cumin hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, diisopropylbenzene hydroperoxide, p-menthane hydroperoxide, and the like; bibenzyl compounds such as 2,3-dimethyl-2,3-diphenylbutane, and the like; and 3,3,5,7,7-pentamethyl-1,2,4-trioxepane, and the like.

[0040] Examples of photoradical polymerization initiators include benzoin alkyl ether, benzil dimethyl ketal, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, benzophenone, methylbenzoyl formate, isopropyl thioxanthone, and mixtures of two or more thereof. Sensitizers can also be used in conjunction with these photoradical polymerization initiators. Examples of sensitizers include carbonyl compounds such as anthraquinone, 1,2-naphthoquinone, 1,4-naphthoquinone, benzanthrone, p,p'-tetramethyldiaminobenzophenone, and chloranil; nitro compounds such as nitrobenzene, p-dinitrobenzene, and 2-nitrofluorene; aromatic hydrocarbons such as anthracene and chrysene; sulfur compounds such as diphenyl disulfide; and nitrogen compounds such as nitroaniline, 2-chloro-4-nitroaniline, 5-nitro-2-aminotoluene, and tetracyanoethylene.

[0041] When the total amount of the polyfunctional (meth)acrylic acid thioester composition and compound (B) in the curable composition according to the present invention is taken as 100 parts by mass, from the viewpoint of further improving the performance balance of high refractive index, low cure shrinkage, and glass adhesiveness of the obtained cured product, the content of the polymerization initiator in the curable composition according to the present invention is preferably 0.1 parts by mass or more, more preferably 0.5 parts by mass or more, even more preferably 1.0 parts by mass or more, even more preferably 1.5 parts by mass or more, even more preferably 2.0 parts by mass or more, even more preferably 2.5 parts by mass or more, and preferably 10 parts by mass or less, more preferably 8.0 parts by mass or less, even more preferably 5.0 parts by mass or less, and even more preferably 4.0 parts by mass or less.

[0042] The curable composition according to the present invention preferably contains a silane coupling agent from the viewpoint of further improving the balance of the performance of the resulting cured product, including a high refractive index, low cure shrinkage, and glass adhesion. Examples of the silane coupling agent include vinyltrimethoxysilane, vinyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N-2-(amino Examples of suitable silane coupling agents include N-(vinylbenzyl)-2-aminoethyl-3-aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-triethoxysilyl-N-(1,3-dimethylbutylidene)propylamine, N-phenyl-3-aminopropyltrimethoxysilane, N-(vinylbenzyl)-2-aminoethyl-3-aminopropyltrimethoxysilane hydrochloride, tris-(trimethoxysilylpropyl)isocyanurate, 3-ureidopropyltrialkoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-isocyanatepropyltriethoxysilane, and 3-trimethoxysilylpropylsuccinic anhydride. These silane coupling agents are sold by Shin-Etsu Chemical Co., Ltd. and other companies, and are therefore readily available on the market.

[0043] When the total amount of the polyfunctional (meth)acrylic acid thioester composition and compound (B) in the curable composition according to the present invention is taken as 100 parts by mass, the content of the silane coupling agent in the curable composition according to the present invention is, from the viewpoint of further improving the performance balance of high refractive index, low cure shrinkage, and glass adhesiveness of the obtained cured product, preferably 0.001 parts by mass or more, more preferably 0.01 parts by mass or more, even more preferably 0.1 parts by mass or more, even more preferably 0.5 parts by mass or more, and preferably 10 parts by mass or less, more preferably 5.0 parts by mass or less, even more preferably 3.0 parts by mass or less, and even more preferably 1.5 parts by mass or less.

[0044] The curable composition according to the present invention preferably contains an ultraviolet absorber from the viewpoint of further improving ultraviolet resistance. Examples of the ultraviolet absorber include benzophenone-based ultraviolet absorbers, benzotriazole-based ultraviolet absorbers, triazine-based ultraviolet absorbers, and benzoxazine-based ultraviolet absorbers. Examples of the benzophenone-based ultraviolet absorbers include 4-methoxy-2-hydroxybenzophenone (molecular weight 228), 4-methoxy-2-hydroxybenzophenone-5-sulfonic acid (molecular weight 308), 2,4-dihydroxybenzophenone (molecular weight 214), 4,4'-dimethoxy-2,2'-dihydroxybenzophenone (molecular weight 274), and 4,4'-dimethoxy-2,2'-dihydroxy-5,5'-disulfonic acid benzophenone disodium (molecular weight 478), 2,2'-4,4'-tetrahydroxybenzophenone (molecular weight 246), sodium hydroxymethoxybenzophenone sulfonate (molecular weight 376), octabenzone (molecular weight 326), 2-hydroxy-4-m-octoxybenzophenone (molecular weight 345), 2-hydroxy-4-n-octoxybenzophenone (molecular weight 326), bis(5-benzoyl-4-hydroxy-2-methoxyphenyl)methane (molecular weight 468), etc. Examples of benzotriazole-based ultraviolet absorbers include 2-(2H-benzotriazol-2-yl)-p-cresol (molecular weight 225), 2-(2H-benzotriazol-2-yl)-4,6-bis(1-methyl-1-phenylethyl)phenol (molecular weight 448), 2-[5-chloro(2H)-benzotriazol-2-yl]-4-methyl-6-(tert-butyl)phenol (molecular weight 316), 2,4-di-tert-butyl-6-(5-chloro-2H-1,2,3-benzotriazol-2-yl)phenol (molecular weight 358), 2-(2H-benzotriazol-2-yl)-4,6-tert-pentylphenol (molecular weight 352), 2-(2H-benzotriazol-2-yl)-4,6-tert-pentylphenol (molecular weight 352), and 2-(2H-benzotriazol-2-yl)-4,6-bis(1-methyl-1-phenylethyl)phenol (molecular weight 448). Examples of such benzotriazoles include 2-(2-hydroxy-3'-tert-butyl-5'-methylphenyl)-5-chlorobenzotriazole, 2-(2'-hydroxy-3'5-di-tert-butyl-phenyl)-5-chlorobenzotriazole (molecular weight 357), 2-(2'-hydroxy-5'-methylphenyl)benzotriazole (molecular weight 225), and 2-(2-hydroxy-5-octylphenyl)benzotriazole (molecular weight 323). Further, examples of triazine-based ultraviolet absorbers include 2-(4,6-diphenyl-1,3,5-triazin-2-yl)-5-[(hexyl)oxy]-phenol (molecular weight 426), 2-[4,6-bis(2,4-dimethylphenyl)-1,3,5-triazin-2-yl]-5-(octyloxy)phenol (molecular weight 509), 2,4,6-tris(2-hydroxy-4-hexyloxy-3-methylphenyl)phenol (molecular weight 509), and 2,4,6-tris(2-hydroxy-4-hexyloxy-3-methylphenyl)phenol (molecular weight 509). Examples of suitable amines include 2-(4,6-diphenyl-1,3,5-triazine (molecular weight 700), 2-(4,6-diphenyl-1,3,5-triazin-2-yl)-5-[2-(2-ethylhexanoyloxy)ethoxy]phenol (molecular weight 512), 1,6-hexanediamine, N,N'-bis(1,2,2,6,6-pentamethyl-4-piperidyl), and polymers morpholine-2,4,6-trichloro-1,3,5-triazine. An example of a benzoxazine-based ultraviolet absorber is 2,2'-(1,4-phenylene)bis(4H-3,1-benzoxazin-4-one) (molecular weight: 368). Other examples include tetra-ethyl-2,2-(1,4-phenylene-dimethylidene-bismalonic acid) (molecular weight: 418) having a malonic acid ester structure, and 2-ethyl,2'-ethoxy-oxamide (molecular weight: 312) having an oxalic acid anilide structure. Two or more of the above-mentioned components can also be used in combination.

[0045] When the total amount of the polyfunctional (meth)acrylic acid thioester composition and compound (B) in the curable composition according to the present invention is taken as 100 parts by mass, the content of the ultraviolet absorber in the curable composition according to the present invention is, from the viewpoint of further improving the performance balance of a high refractive index, low cure shrinkage, glass adhesion, and ultraviolet resistance of the obtained cured product, preferably 0.001 part by mass or more, more preferably 0.005 part by mass or more, even more preferably 0.01 part by mass or more, and preferably 1.0 part by mass or less, more preferably 0.5 part by mass or less, even more preferably 0.2 part by mass or less, and even more preferably 0.1 part by mass or less.

[0046] The curable composition according to the present invention preferably contains an antioxidant from the viewpoint of further improving oxidation resistance. Examples of the antioxidant include triethylene glycol-bis[3-(3-tert-butyl-5-methyl-4-hydroxyphenyl)propionate], 1,6-hexanediol-bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], pentaerythritol-tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, and 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxyphenyl)propionate. tert-butyl-4-hydroxybenzyl)benzene, N,N-hexamethylenebis(3,5-di-tert-butyl-4-hydroxy-hydrocinnamide), 3,5-di-tert-butyl-4-hydroxy-benzylphosphonate-diethyl ester, tris(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanurate, and 3,9-bis{1,1-dimethyl-2-[β-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy]ethyl}-2,4,8,10-tetraoxaspiro(5,5)undecane.

[0047] When the total amount of the polyfunctional (meth)acrylic acid thioester composition and compound (B) in the curable composition according to the present invention is taken as 100 parts by mass, the content of the antioxidant in the curable composition according to the present invention is, from the viewpoint of further improving the performance balance of the resulting cured product, including high refractive index, low cure shrinkage, glass adhesion, and oxidation resistance, preferably 0.01 parts by mass or more, more preferably 0.05 parts by mass or more, even more preferably 0.1 parts by mass or more, and preferably 5.0 parts by mass or less, more preferably 2.0 parts by mass or less, and even more preferably 1.0 part by mass or less.

[0048] From the viewpoint of further improving weather resistance, the curable composition according to the present invention preferably contains a light stabilizer, more preferably a hindered amine light stabilizer. Examples of the hindered amine light stabilizer include methacrylic acid (1,2,2,6,6-pentamethyl-piperidin-4-yl), decanedioic acid bis(2,2,6,6-tetramethyl-1(octyloxy)-4-piperidinyl) ester, a reaction product of 70% by weight of 1,1-dimethylethyl hydroperoxide and octane and 30% by weight of polypropylene, bis(1,2,2,6,6-pentamethyl-4-piperidyl)[[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methyl]butylmalonate, bis(1,2,2,6,6-pentamethyl-4-piperidyl)sebacate, and methyl-1,2,2,6,6-pentamethyl-4-piperidylsebacate mixtures. a mixture of 2,2,6,6-tetramethyl-4-piperidyl-1,2,3,4-butanetetracarboxylate, bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate, tetrakis(2,2,6,6-tetramethyl-4-piperidyl)-1,2,3,4-butanetetracarboxylate, tetrakis(1,2,2,6,6-pentamethyl-4-piperidyl)-1,2,3,4-butanetetracarboxylate, a mixture of 2,2,6,6-tetramethyl-4-piperidyl-1,2,3,4-butanetetracarboxylate and tridecyl-1,2,3,4-butanetetracarboxylate, and a mixture of 1,2,2,6,6-pentamethyl-4-piperidyl-1,2,3,4-butanetetracarboxylate and tridecyl-1,2,3,4-butanetetracarboxylate.

[0049] When the total amount of the polyfunctional (meth)acrylic acid thioester composition and compound (B) in the curable composition according to the present invention is taken as 100 parts by mass, the content of the hindered amine light stabilizer in the curable composition according to the present invention is, from the viewpoint of further improving the performance balance of a high refractive index, low cure shrinkage, glass adhesion, and weather resistance of the obtained cured product, preferably 0.01 parts by mass or more, more preferably 0.03 parts by mass or more, even more preferably 0.05 parts by mass or more, and preferably 5.0 parts by mass or less, more preferably 1.0 part by mass or less, even more preferably 0.5 parts by mass or less, and even more preferably 0.2 parts by mass or less.

[0050] In the curable composition according to the present invention, the specific gravity of the curable composition measured using a pycnometer in accordance with JIS Z 8804:2012 is d 1 The specific gravity of a 250 μm thick test piece made of the cured product of the curable composition according to the present invention is d 2 Then, (1-d 1 / d 2 The cure shrinkage of the curable composition, expressed as [(x,y) / (y)] × 100, is preferably 9.0% or less, more preferably 8.0% or less, even more preferably 7.0% or less, and still more preferably 6.5% or less. The lower limit of the cure shrinkage is not particularly limited, and may be, for example, 0.1% or more, 1.0% or more, 3.0% or more, 4.0% or more, or 5.0% or more. In this embodiment, a test piece having a thickness of 250 μm and made of a cured product of the curable composition according to the present invention is, for example, a curable film made of the curable composition applied to a glass substrate, and the exposure dose at 365 nm is 1000 mJ / cm 2 2 The cured product is then heated at 80°C for 30 minutes in a nitrogen gas atmosphere.

[0051] <Method for producing curable composition> The curable composition according to the present invention can be obtained by mixing the compound (B) and other components, if necessary, with the polyfunctional (meth)acrylic acid thioester composition by a conventionally known method.

[0052] The total content of the polyfunctional (meth)acrylic acid thioester composition and the compound (B) in the curable composition according to the present invention, when the entire curable composition is taken as 100% by mass, is preferably 70% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, still more preferably 95% by mass or more, and preferably 100% by mass or less, from the viewpoint of further improving the performance balance of high refractive index, low cure shrinkage, and glass adhesiveness of the obtained cured product.

[0053] [Cured product] The cured product according to the present invention is obtained by curing the curable composition according to the present invention. The cured product according to the present invention has an improved balance of high refractive index, low cure shrinkage, and glass adhesion, and is therefore suitable for use as an optical material.

[0054] When a 250 μm-thick test piece is prepared from the cured product according to this embodiment, the light transmittance (T1) of the test piece at a wavelength of 400 nm is preferably 81% or more, more preferably 83% or more, even more preferably 84% or more, and even more preferably 85% or more, from the viewpoint of further improving the transparency of the cured product. The upper limit of the light transmittance (T1) is not particularly limited, and may be, for example, less than 100%, or may be 99% or less, 95% or less, or 90% or less. In this embodiment, a test piece having a thickness of 250 μm and made of the cured product according to this embodiment is, for example, a curable film made of the curable composition applied to a glass substrate, and the exposure dose at 365 nm is 1000 mJ / cm 2 2 The cured product is then heated at 80°C for 30 minutes in a nitrogen gas atmosphere.

[0055] Furthermore, for the cured product according to this embodiment, when a 250 μm-thick test piece is prepared using the cured product and the resulting test piece is heated in an oven set to 125° C. in an air atmosphere for 168 hours, and the light transmittance of the test piece at a wavelength of 400 nm after the heat treatment is designated as T2, the rate of change in light transmittance after heating, expressed as (T1-T2) / T1×100, is preferably 7.0% or less, more preferably 5.0% or less, even more preferably 4.0% or less, and even more preferably 3.0% or less. The lower limit of the rate of change in light transmittance after heating is not particularly limited, and may be, for example, 0.1% or more, optionally 0.5% or more, optionally 0.8% or more, or optionally 1.0% or more.

[0056] When a 250 μm-thick test piece made of the cured product according to this embodiment is prepared, the refractive index (nD) of the test piece at the D line (589.3 nm) is preferably 1.600 or more, more preferably 1.610 or more, even more preferably 1.620 or more, even more preferably 1.630 or more, even more preferably 1.635 or more, even more preferably 1.640 or more, and even more preferably 1.645 or more, from the viewpoint of further improving the optical properties of the cured product. The upper limit of the refractive index (nD) of the test piece at the D line (589.3 nm) is not particularly limited, and may be, for example, 1.700 or less, 1.680 or less, 1.655 or less, or 1.650 or less.

[0057] When a 250 μm-thick test piece made of the cured product according to this embodiment is prepared, the Abbe number (νD) of the test piece, measured in accordance with ASTM D542, is, from the viewpoint of further improving the optical properties of the cured product, preferably 20 or more, more preferably 25 or more, even more preferably 28 or more, even more preferably 30 or more, even more preferably 32 or more, and even more preferably 33 or more. The upper limit of the Abbe number (νD) of the test piece is not particularly limited, and is, for example, 45 or less, or may be 42 or less, 40 or less, or 38 or less.

[0058] [Molded body] The molded article according to the present invention is a molded article containing the cured product according to the present invention, and can be obtained, for example, by molding the curable composition according to the present invention into a predetermined shape while curing it. The molded article of the present invention contains the cured product of the present invention, and therefore has an improved balance of performance such as high refractive index, low cure shrinkage, and glass adhesion, and can therefore be suitably used as an optical material.

[0059] From the viewpoint of further improving the performance balance of high refractive index, low cure shrinkage, and glass adhesiveness, the content of the cured product according to the present invention in the molded article according to the present invention is preferably 50% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, even more preferably 90% by mass or more, even more preferably 95% by mass or more, even more preferably 97% by mass or more, and preferably 100% by mass or less, when the entire molded article is taken as 100% by mass.

[0060] [Optical materials] The optical material according to the present invention includes the molded article according to the present invention, and can be obtained, for example, by molding the curable composition according to the present invention into a predetermined shape while curing it. The optical material according to the present invention contains the cured product or molded article according to the present invention, and therefore has an improved balance of performance properties such as high refractive index, low cure shrinkage, and glass adhesion. Examples of the optical material according to the present invention include various optical lenses such as lenses for various sensors, pickup lenses, projector lenses, prisms, fθ lenses, imaging lenses, camera lenses, light guide plates, lenses for head-mounted displays, plastic eyeglass lenses, goggles, eyeglass lenses for vision correction, lenses for imaging devices, Fresnel lenses for liquid crystal projectors, lenticular lenses, and contact lenses; encapsulants for light-emitting diodes (LEDs); optical waveguides; optical adhesives used for bonding wafer-level optics (WLO) and optical waveguides; anti-reflection films used in optical lenses; transparent coatings used in liquid crystal display device components (substrates, light guide plates, films, sheets, etc.); sheets or films to be attached to car windshields or motorcycle helmets; and transparent substrates. The optical material according to the present invention has an improved balance of performances including a high refractive index, low cure shrinkage, and glass adhesion, and can therefore be suitably used as various optical lenses. Furthermore, the optical material according to the present invention has an improved balance of performance among high refractive index, low cure shrinkage, and glass adhesion, and therefore can further contain a glass substrate and be suitably used as a laminate of the molded article according to the present invention and the glass substrate, and can further be suitably used as a so-called hybrid optical lens in which a resin lens is formed on a glass substrate.

[0061] Although the embodiments of the present invention have been described above, these are merely examples of the present invention, and various other configurations can also be adopted. Furthermore, the present invention is not limited to the above-described embodiment, and modifications and improvements within the scope of achieving the object of the present invention are included in the present invention. [Example]

[0062] The present embodiment will be described in detail below with reference to examples, etc. However, the present embodiment is not limited to the descriptions of these examples.

[0063] Example 1 (Preparation of Curable Composition) The composition (100 parts by weight) obtained in Synthesis Example 2 as a polyfunctional (meth)acrylic acid thioester composition and Irg184 (1-hydroxycyclohexyl phenyl ketone, manufactured by BASF, 3.0 parts by weight) as a polymerization initiator were added to a sample bottle, and mixed using a mix rotor until the appearance became uniform, thereby obtaining a curable composition. The viscosity of the resulting curable composition at 25° C. was measured using an E-type viscometer (TVE-25L, manufactured by Toki Sangyo Co., Ltd.) at a rotation speed of 2.5 rpm.

[0064] (Preparation of cured film) 0.5 mL of the curable composition was applied to Eagle-XG (an alkali-free glass substrate manufactured by Corning, 70 × 70 × 0.7 mmT) that had been treated with Novec 1720 (a fluorinated silane-based coating agent manufactured by 3M) for release treatment, and the substrate was sandwiched between another glass substrate that had also been treated with release treatment via a 250 μm-thick spacer, and the edges were fixed with clips. The resulting laminate was exposed to light from one side using an electrodeless lamp (H bulb) at 365 nm with an exposure dose of 1000 mJ / cm 2 After irradiating with ultraviolet light so as to obtain a cured film having a thickness of 250 μm, the cured product was released from the glass substrate and heated at 80° C. for 30 minutes in a nitrogen gas atmosphere to obtain a cured film having a thickness of 250 μm. The refractive index and shrinkage upon curing of the resulting cured film were measured by the methods described below. The results are shown in Table 1.

[0065] <Measurement of refractive index (nD) and Abbe number (νD)> The refractive index (nD) and Abbe number (νD) were measured in accordance with ASTM D542 as follows. The refractive index (nD) of the cured film at D line (589.3 nm) was measured using an Abbe refractometer (DR-M2, manufactured by Atago Co., Ltd.) using RE-3520 (D line, manufactured by Atago Co., Ltd.) as an interference filter and RE-1196 (monobromonaphthalene, manufactured by Atago Co., Ltd.) as an intermediate liquid, and the sample temperature was set to 25°C. The refractive index (nC) of the cured film at C-line (wavelength 656.3 nm) was measured using an Abbe refractometer (DR-M2, manufactured by Atago Co., Ltd.) with RE-3522 (C-line, manufactured by Atago Co., Ltd.) as an interference filter and RE-1196 (monobromonaphthalene, manufactured by Atago Co., Ltd.) as an intermediate liquid, and the sample temperature was set to 25°C. The refractive index (nF) of the cured film at F-line (wavelength 486.1 nm) was measured using a refractometer (DR-M2, manufactured by Atago Co., Ltd.) with RE-3521 (F-line, manufactured by Atago Co., Ltd.) as an interference filter and RE-1196 (monobromonaphthalene, manufactured by Atago Co., Ltd.) as an intermediate liquid, and the sample temperature was set to 25°C. The Abbe number of the cured film was then calculated according to the following formula. Abbe number = (nD-1) / (nF-nC)

[0066] <Light transmittance> The light transmittance in the thickness direction of the obtained cured film was measured under the following conditions to obtain a light transmittance T1. The measurement was performed by attaching the cured film to an integrating sphere, with the light incident surface being an arbitrary surface. (Measurement conditions) Measurement equipment: UH4150 (Hitachi High-Tech Science ultraviolet-visible near-infrared spectrophotometer) Measurement method: Transmission method Measurement wavelength: 400 nm Reference: Atmosphere Detector: Integrating sphere / photomultiplier tube (200nm~850nm) Integrating sphere: PbS (850nm~2600nm)

[0067] <Change in light transmittance after heating (125°C for 168 hours)> First, the obtained cured film was heated in an oven set to 125°C in an air atmosphere for 168 hours. Then, the light transmittance in the thickness direction was measured under the above conditions to obtain the light transmittance after heating T2, which was calculated using the following formula. The results are shown in Table 1. Change in light transmittance after heating (125℃ 168 hours) (%) =(T1-T2) / T1×100

[0068] <Measurement of cure shrinkage rate> Specific gravity d of the curable composition 1 was measured using a pycnometer (JIS Z 8804:2012). 2 was measured by the Archimedes method (JIS Z 8807:2012). Using these specific gravity values, the cure shrinkage rate (%) was calculated according to the following formula. Formula: Curing shrinkage rate (%) = (1 - d 1 / d 2 ) x 100

[0069] <Evaluation of glass adhesion> 0.5 mL of the curable composition was applied to an Eagle-XG substrate (an alkali-free glass substrate manufactured by Corning, 70 × 70 × 0.7 mmT) that had been treated with Novec 1720 (a fluorinated silane coating agent manufactured by 3M) for release treatment, and the substrate was sandwiched between two Eagle-XG substrates (an alkali-free glass substrate manufactured by Corning, 70 × 70 × 0.7 mmT) that had not been treated for release treatment, with a 250 μm-thick spacer interposed between them, and the edges were fixed with clips. The resulting laminate was exposed to light from one side using an electrodeless lamp (H bulb) at 365 nm with an exposure dose of 1000 mJ / cm 2 After irradiating with ultraviolet light, the cured product is released from the release-treated glass substrate. The mixture was heated at 80° C. for 30 minutes in a nitrogen gas atmosphere to obtain a cured resin / glass substrate laminate. The obtained laminate was evaluated for glass adhesion according to the following evaluation criteria. The evaluation results are shown in Table 1. (Evaluation criteria) PASS (good): No peeling at the resin / glass substrate interface or cracks in the resin were observed. FAIL (bad): Peeling at the resin / glass substrate interface and cracks in the resin were observed.

[0070] <Examples 2 to 5 and Comparative Examples 1 and 2> Each evaluation was carried out in the same manner as in Example 1, except that the composition of the curable composition was changed to the composition shown in Table 1. Table 1 shows the composition of the curable composition and the results of each evaluation.

[0071] [Table 1]

[0072] The details of each component shown in Table 1 are as follows: GSTA: 1,8-bisacryloylthio-(4-acryloylthiomethyl-3,6-dithiaoctane (prepared according to Synthesis Example 1 below)

[0073] A-BPEF (fluorene-based acrylate monomer (9,9-bis(4-(2-acryloyloxyethoxy)phenyl)fluorene), manufactured by Shin-Nakamura Scientific Co., Ltd., compound with the following structure)

[0074] [ka]

[0075] (Other ingredients) Irg184: Polymerization initiator (1-hydroxycyclohexyl phenyl ketone, manufactured by BASF, compound with the following structure)

[0076] [ka] KBM-5103: Silane coupling agent (3-acryloxypropyltrimethoxysilane, manufactured by Shin-Etsu Chemical Co., Ltd., compound with the following structure)

[0077] [ka]

[0078] AO-60: Antioxidant (pentaerythritol-tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] manufactured by ADEKA Corporation, compound with the following structure)

[0079] [ka] LA-82: Hindered amine light stabilizer (1,2,2,6,6-pentamethyl-piperidin-4-yl methacrylate, manufactured by ADEKA Corporation, compound with the following structure)

[0080] [ka] LA-46: UV absorber (2-(4,6-diphenyl-1,3,5-triazin-2-yl)-5-[2-(2-ethylhexanoyloxy)ethoxy]phenol, a compound with the following structure, manufactured by ADEKA Corporation)

[0081] [ka]

[0082] (Synthesis Example 1: Synthesis of GSTA) A four-neck flask equipped with a stirrer, thermometer, nitrogen inlet line, and dropping funnel was charged with 4-mercaptomethyl-1,8-dimercapto-3,6-dithiaoctane (GST, 100.0 g, 383.9 mmol), diluted with dichloromethane (100 mL), and stirring was initiated. Next, 3-chloropropionyl chloride (121.84 g, 959.7 mmol) was added dropwise while the reaction solution was cooled in an ice bath to maintain the internal temperature at 40°C or below. After stirring the reaction mixture at room temperature for 48 hours, 100 mL of pure water was added and the organic phase was separated by a separation operation. The resulting organic phase was washed twice with 100 mL of saturated aqueous sodium bicarbonate solution, and the solvent was removed by evaporation to obtain the compound (201.0 g) of the following structure.

[0083] [ka]

[0084] The resulting compound was placed in a four-neck flask equipped with a thermometer and a dropping funnel, and 4-methoxyphenol (150 mg) was added as a polymerization inhibitor and dissolved at room temperature with stirring. Next, triethylamine (116.5 g, 1152 mmol) was added dropwise while the reaction solution was cooled in an ice bath so that the internal temperature was below 40°C. After stirring the reaction mixture at room temperature for 1 hour, 1M hydrochloric acid (300 mL) was added, and the organic phase was separated by a separation operation. The resulting organic phase was passed through silica gel (100 mL), and 4-methoxyphenol (150 mg) was added as a polymerization inhibitor. The mixture was then concentrated under reduced pressure to obtain 110.0 g of a colorless, transparent compound (GSTA) with the following structure. The molecular weight was measured by gel permeation chromatography (GPC), revealing a number average molecular weight (Mn) of 400 and a weight average molecular weight (Mw) of 440.

[0085] [ka]

[0086] (Synthesis Example 2) A four-neck flask equipped with a stirrer, thermometer, nitrogen inlet line, and dropping funnel was charged with GSTA (9.0 g) obtained in Synthesis Example 1 and bis(2-mercaptoethyl) sulfide (1.0 g). Next, triethylamine (10 mg) was added while the reaction solution was cooled in an ice bath to maintain the internal temperature below 30°C. After stirring the reaction solution at room temperature for 24 hours, 1 M hydrochloric acid (100 mL) and dichloromethane (100 mL) were added, and the organic phase was separated by separation. The resulting organic phase was passed through silica gel (10 mL), and 4-methoxyphenol (10 mg) was added as a polymerization inhibitor. The mixture was then concentrated under reduced pressure to obtain a colorless, transparent polyfunctional (meth)acrylic acid thioester composition (9.9 g) containing the following compound. The molecular weight was measured by GPC, revealing a number average molecular weight (Mn) of 600 and a weight average molecular weight (Mw) of 3500.

[0087] [ka]

[0088] (Synthesis Example 3) GST (trithiol, 100.0 g, 383.9 mmol) was placed in a four-neck flask equipped with a stirrer, thermometer, nitrogen inlet line, and dropping funnel, diluted with dichloromethane (100 mL), and stirring was initiated. Next, 3-chloropropionyl chloride (121.84 g, 959.7 mmol) was added dropwise while the reaction solution was cooled in an ice bath to maintain the internal temperature below 40°C. The reaction mixture was stirred at room temperature for 48 hours, after which 100 mL of purified water was added and the organic phase was separated by a separation procedure. The resulting organic phase was washed twice with 100 mL of saturated aqueous sodium bicarbonate to obtain a dichloromethane solution of a composition containing GST (compound group below) in which some of the thiol groups of GST had been converted to 3-chloropropionate esters. The peak area ratio of the tri-substituted:di-substituted:mono-substituted GSTs measured by high-performance liquid chromatography (HPLC) was 56:38:6.

[0089] [ka]

[0090] [ka]

[0091] [ka]

[0092] The resulting solution was placed in a four-neck flask equipped with a stirrer, a thermometer, and a dropping funnel, and 4-methoxyphenol (150 mg) was added as a polymerization inhibitor and dissolved with stirring at room temperature. Next, triethylamine (116.5 g, 1152 mmol) was added dropwise while the reaction solution was cooled in an ice bath so that the internal temperature was below 40°C. After stirring the reaction mixture at room temperature for 1 hour, 1M hydrochloric acid (300 mL) was added, and the organic phase was separated by a separation operation. The resulting organic phase was passed through silica gel (100 mL), and 4-methoxyphenol (150 mg) was added as a polymerization inhibitor. The mixture was then concentrated under reduced pressure to obtain a colorless, transparent polyfunctional (meth)acrylic acid thioester composition (132.5 g) containing the following compound. The molecular weight was measured by GPC, and the number average molecular weight (Mn) was 500, and the weight average molecular weight (Mw) was 1600.

[0093] [ka]

[0094] (Synthesis Example 4) A four-neck flask equipped with a stirrer, a thermometer, a nitrogen inlet line, and a dropping funnel was charged with MES (bis(2-mercaptoethyl) sulfide, 100.0 g, 648.1 mmol), diluted with dichloromethane (100 mL), and stirring was initiated. Next, 3-chloropropionyl chloride (123.42 g, 972.1 mmol) was added dropwise while the reaction solution was cooled in an ice bath so that the internal temperature was 40°C or less. After stirring the reaction mixture at room temperature for 48 hours, pure water (100 mL) was added and the organic phase was separated by a separation operation. The resulting organic phase was washed twice with saturated aqueous sodium bicarbonate solution (100 mL) to obtain a dichloromethane solution of a composition containing MES (compounds shown below) in which some of the thiol groups of MES were converted to 3-chloropropionate esters.

[0095] [ka]

[0096] The resulting solution was placed in a four-necked flask equipped with a stirrer, a thermometer, and a dropping funnel, and 4-methoxyphenol (150 mg) was added as a polymerization inhibitor and dissolved with stirring at room temperature. Next, triethylamine (144.28 g, 1430 mmol) was added dropwise while the reaction solution was cooled in an ice bath so that the internal temperature was below 40°C. After stirring the reaction mixture at room temperature for 1 hour, 1M hydrochloric acid (300 mL) was added, and the organic phase was separated by a separation operation. The resulting organic phase was passed through silica gel (100 mL), and 4-methoxyphenol (150 mg) was added as a polymerization inhibitor. The mixture was then concentrated under reduced pressure to obtain a colorless, transparent polyfunctional (meth)acrylic acid thioester composition (121.5 g) containing the following compound. The molecular weight was measured by GPC, and the number average molecular weight (Mn) was 700, and the weight average molecular weight (Mw) was 2000.

[0097] [ka]

[0098] (molecular weight measurement) The number average molecular weight (Mn) and weight average molecular weight (Mw) of the polyfunctional (meth)acrylic acid thioester compositions in Synthesis Examples 1 to 4 were measured by gel permeation chromatography (GPC) according to the following procedure. (1) Preparation of sample solution The polyfunctional (meth)acrylic acid thioester composition was dissolved in tetrahydrofuran to a concentration of 1 g / 100 mL, and then the solution was filtered through a filter with a pore size of 1 μm (manufactured by Membrane Solutions, product name: Syringe Filter PTFE013100) to remove insoluble components, thereby obtaining a sample solution. (2) Molecular weight measurement Using a GPC measurement device (product name: Alliance, manufactured by WATERS), tetrahydrofuran (Fujifilm Wako Pure Chemical Industries, for high-performance liquid chromatography) was flowed as the eluent at a flow rate of 1.0 mL / min. Three analytical columns (gel permeation columns, manufactured by Agilent, product name: PLgel 5 μm Mixed-C) connected in series were stabilized in a constant temperature bath at 40 °C. 10 μL of the sample solution was injected into the column for measurement. A differential refractive index (RI) detector was used as the detector. The molecular weight of the sample was calculated based on a calibration curve prepared in advance. The calibration curve was prepared using several types of monodisperse polystyrene (manufactured by Agilent) with known molecular weights as standard samples.

[0099] This application claims priority based on Japanese Patent Application No. 2022-052197, filed on March 28, 2022, the disclosure of which is incorporated herein in its entirety.

Claims

1. A curable composition containing a polyfunctional (meth)acrylic acid thioester composition, which contains a polyfunctional (meth)acrylic acid thioester compound (A) represented by the following formula (1): the content of the compound (A) in the polyfunctional (meth)acrylic acid thioester composition is 70% by mass or more, when the entire polyfunctional (meth)acrylic acid thioester composition is taken as 100% by mass; the content of the polyfunctional (meth)acrylic acid thioester composition in the curable composition is 50 parts by mass or more relative to 100 parts by mass of the curable composition; A curable composition, wherein in the following formula (1), in X, the number of alkylene groups substituted with a structure of the following formula (2) is 2: 【Chemistry 1】 (In the formula (1), n ​​is an integer of 5 or more, X represents an alkylene group having 1 to 4 carbon atoms in which any methylene group may be substituted with a carbonyl group, any hydrogen atom in the alkylene group is substituted with a structure of the following formula (2), and R １ and R ２ each independently represents a hydrogen atom or a methyl group. 【Chemistry 2】 (In the formula (2), R ３ represents a hydrogen atom or a methyl group, and a plurality of R ３ may be the same or different, W represents an alkylene group having 1 to 4 carbon atoms, and o is an integer of 1 or more.

2. The curable composition according to claim 1, wherein the weight average molecular weight of the polyfunctional (meth)acrylic acid thioester composition is 1,000 or more and 100,000 or less.

3. The curable composition according to claim 1 or 2, wherein the polyfunctional (meth)acrylic acid thioester compound (A) comprises at least one selected from the group consisting of a compound represented by the following formula (3) and a compound represented by the following formula (4): 【Transformation 3】 【Chemistry 4】 (In the formulas (3) and (4), m and n each independently represent an integer of 2 or more, X and Y each independently represent an alkylene group having 1 to 4 carbon atoms in which any hydrogen atom may be substituted with the structure of the formula (2), and multiple Xs and Ys may be the same or different, and R １ and R ２ each independently represents a hydrogen atom or a methyl group.

4. The curable composition according to claim 1 or 2, further comprising a compound (B) represented by the following formula (5): 【Transformation 5】 (In the formula (5), Z １ and Z ２ each independently represents an aromatic carbon ring or an alkylene group, any hydrogen atom of which may be substituted by an alkyl group or an alkoxy group; Z ３ and Z ４ each independently represents an aromatic carbon ring or an alkyl group, any hydrogen atom of which may be substituted with an alkyl group or an alkoxy group; R １ and R ３ each independently represents an alkylene group having 1 to 10 carbon atoms; R ２ and R ４ each independently represents a hydrogen atom or a methyl group, R ５ and R ６ each independently represents an alkyl group, m and n each independently represents an integer of 0 or greater, and o, p, q, and r each represent an integer of 0 or greater that satisfies the relationships o+q≦4, p+r≦4.

5. 3. The curable composition according to claim 1, wherein the viscosity of the curable composition at 25°C, measured using an E-type viscometer at a rotation speed of 2.5 rpm, is 100 mPa·s or more and 10,000 mPa·s or less.

6. The curable composition according to claim 1 or 2, further comprising a polymerization initiator.

7. The curable composition according to claim 1 or 2, further comprising at least one selected from the group consisting of a silane coupling agent, an antioxidant, an ultraviolet absorber, and a light stabilizer.

8. The specific gravity of the curable composition measured using a pycnometer in accordance with JIS Z 8804: 2012 is d １ The specific gravity of a 250 μm thick test piece made of the cured product of the curable composition was d ２ When this is the case, (1-d １ / d ２ 3. The curable composition according to claim 1, wherein the curing shrinkage of the curable composition is 9.0% or less, as calculated by multiplying the cured product by 100 times the curing shrinkage of the curable composition ...

9. The curable composition according to claim 1 or 2, which can be used for optical materials.

10. A cured product obtained by curing the curable composition according to claim 1 or 2.

11. When a test piece having a thickness of 250 μm was prepared from the cured product, the light transmittance (T １ 11. The cured product according to claim 10, wherein the % of the total polymer content is 81% or more.

12. The test piece was heated in an oven set at 125° C. in an air atmosphere for 168 hours, and the light transmittance of the test piece at a wavelength of 400 nm after the heat treatment was measured. ２ When this is done, (T １ -T ２ 12. The cured product according to claim 11, wherein the rate of change in light transmittance after heating, expressed as (T1) / T1×100, is 7.0% or less.

13. The cured product according to claim 10, wherein when a test piece having a thickness of 250 μm is prepared from the cured product, the refractive index (nD) of the test piece at D line (589.3 nm) is 1.600 or more.

14. 11. The cured product according to claim 10, wherein a test piece having a thickness of 250 μm is prepared from the cured product, and the Abbe number (νD) of the test piece measured in accordance with ASTM D542 is 20 or more.

15. A molded article comprising the cured product according to claim 10.

16. An optical material comprising the molded article according to claim 15.

17. further comprising a glass substrate; The optical material according to claim 16 , which is a laminate of the molded body and the glass substrate.

18. 17. The optical material according to claim 16, which is an optical lens.

19. 3. A method for producing a polyfunctional (meth)acrylic acid thioester composition contained in the curable composition according to claim 1, comprising the steps of converting 0.5 equivalents or more and 0.9 equivalents or less of all thiol groups in a polythiol compound into functional groups represented by the following structural formula, and then subjecting the resulting compound to a β-elimination reaction and an enethiol reaction, thereby synthesizing a polyfunctional (meth)acrylic acid thioester compound. 【Transformation 6】 (In the structural formula, X represents a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom, and R represents a hydrogen atom or a methyl group.)

20. A method for producing a polyfunctional (meth)acrylic acid thioester composition contained in the curable composition according to claim 1 or 2, comprising a step of reacting a polythiol compound with a polythio(meth)acrylate compound by an enethiol reaction.

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