Curable composition

Abstract

To provide a curable composition that, by irradiation with light or by heating, can give a cured film having high transparency and exhibiting high heat resistance.SOLUTION: A curable composition comprises a double-decker-type silsesquioxane (A) having two or more SH groups, wherein the double-decker-type silsesquioxane (A) having two or more SH groups is at least one selected from the group consisting of a compound represented by formula (A1) and a silsesquioxane in which both terminals of formula (A1) are cleaved. (In the formula, R1 and R2 independently represent a substituted or unsubstituted hydrocarbon group having 1 to 20 carbon atoms; RT1 independently represents a substituted or unsubstituted hydrocarbon group having 2 to 20 carbon atoms and having an SH group. The silsesquioxane in which both terminals are cleaved has at least one hydrocarbon group selected from substituted or unsubstituted hydrocarbon groups having 2 to 20 carbon atoms and having a polymerizable double bond).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a curable composition, and more particularly to a curable composition and a cured film containing a silsesquioxane having a thiol group (SH group). [Background technology]

[0002] In order to increase the data capacity and speed of the Internet and local area networks (LANs) and to suppress the associated increases in power consumption and heat generation, optical interconnection technology using optical signals for short-distance signal transmission between or within boards in routers and server devices is being developed. Polymer materials are preferably used as the optical transmission path in optoelectronic hybrid boards, or so-called co-packaged boards, which combine optical transmission paths with electrical wiring boards. These materials are preferably used because they are easier to process than inorganic materials, allowing for greater flexibility and the wiring of high-density optical waveguides. As mentioned above, optical waveguides made of polymer materials are structured to coexist with electrical wiring boards, so the core material of the optical waveguide is required to have a relatively high refractive index, as well as high transparency (low propagation loss), solder reflow resistance, and high adhesion to the substrate. In order to improve these properties, acrylic materials such as those disclosed in Patent Document 1, thiol-based materials such as those disclosed in Patent Document 2, and polyimides having a silsesquioxane skeleton such as those disclosed in Patent Document 3 have been reported as optical waveguide materials. Adhesives having a high refractive index, such as those disclosed in Patent Document 4, have also been proposed for use in optical components. However, the optical waveguide materials disclosed in Patent Documents 1 and 2 and the adhesive disclosed in Patent Document 4 did not have sufficient heat resistance when used in these applications. Furthermore, the optical waveguide material disclosed in Patent Document 3 did not have sufficient transparency, and improvements in this regard were needed.

[0003] Optical materials using silsesquioxanes to impart high heat resistance and light resistance have also been reported. For example, Patent Document 5 discloses polyimide materials using double-decker silsesquioxane compounds. Patent Document 6 proposes a photosensitive composition that provides a cured product with high heat resistance and transparency, and that can consistently and uniformly convert light emitted from an optical semiconductor over a long period of time. However, the polyimide material described in Patent Document 5 may be discolored. Furthermore, when a polyimide film is obtained from a precursor, significant curing shrinkage can cause wrinkles, resulting in reduced film transparency. The epoxy material described in Patent Document 6 has the above-mentioned favorable properties, but because it uses an acid generator as a curing agent, the material and related components used therewith may be prone to deterioration over time. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-86697 [Patent Document 2] International Publication No. 2015 / 029996 [Patent Document 3] Japanese Patent Application Laid-Open No. 2006-265243 [Patent Document 4] International Publication No. 2016 / 194618 [Patent Document 5] Japanese Patent Application Laid-Open No. 2006-265243 [Patent Document 6] International Publication No. 2012 / 111765 Summary of the Invention [Problem to be solved by the invention]

[0005] This application discloses a technology that overcomes the drawbacks of existing materials. Specifically, it provides a curable material that is highly transparent and heat-resistant, maintaining its properties even after prolonged exposure to high temperatures. Furthermore, because the composition of this application can be cured using a polymerization initiator, it is possible to prevent acidic substances from lurking in the material without any additional steps. [Means for solving the problem]

[0006] As a result of extensive research aimed at solving the above-mentioned problems, the present inventors have found that a composition containing a specific double-decker silsesquioxane (A) having two or more SH groups can be cured by light irradiation or heating in the presence of a polymerization initiator or the like to give a cured film that exhibits high transparency and high heat resistance, and have thus completed the present invention. The present invention includes the following configurations.

[0007] [1] A curable composition comprising a double-decker silsesquioxane (A) having two or more SH groups, wherein the double-decker silsesquioxane (A) having two or more SH groups is at least one selected from the group consisting of silsesquioxanes represented by formula (A1) and formula (A2): TIFF2025187239000001.tif3572 TIFF2025187239000002.tif3582 (In formulas (A1) and (A2), R 1 , R 2 , and R 3 are each independently a substituted or unsubstituted hydrocarbon group having 1 to 20 carbon atoms; R T1 are each independently a substituted or unsubstituted hydrocarbon group having 2 to 20 carbon atoms and having an SH group; R T2 are each independently at least one hydrocarbon group selected from a substituted or unsubstituted hydrocarbon group having 2 to 20 carbon atoms and an SH group, and a substituted or unsubstituted hydrocarbon group having 2 to 20 carbon atoms and a polymerizable double bond, and in this case, at least two R T2 is a substituted or unsubstituted hydrocarbon group having 2 to 20 carbon atoms and an SH group;

[0008] [2] The curable composition according to [1], wherein the double-decker silsesquioxane (A) having two or more SH groups is the following A11, A21, or A22: A11: In formula (A1), all R 1 is -Ph, and two R T1 is -CH2CH2SH. A21: In formula (A2), all R 1 is -Ph and R T2 is -CH2CH2SH or -CH=CH2, the number of -CH2CH2SH is an integer of 2 to 4, and the number of -CH=CH2 is an integer of 2 to 0. A22: In formula (A2), all R 1 is -Ph and R T2 is -CH2CH2CH2SH or -CH2CH=CH2, the number of -CH2CH2CH2SH is an integer of 2 to 4, and the number of -CH2CH=CH2 is an integer of 2 to 0.

[0009] [3] The curable composition according to [1] or [2], further comprising a compound (B) having two or more polymerizable double bonds.

[0010] [4] The curable composition according to any one of [1] to [3], further comprising an organic solvent (C).

[0011] [5] A cured film obtained by curing the curable composition according to any one of [1] to [4].

[0012] [6] An optical material using the cured film described in [5].

[0013] [7] A silsesquioxane represented by formula (A1) or formula (A2): TIFF2025187239000003.tif3572 TIFF2025187239000004.tif3582 (In formulas (A1) and (A2), R 1 , R 2 , and R 3are each independently a substituted or unsubstituted hydrocarbon group having 1 to 20 carbon atoms; R T1 are each independently a substituted or unsubstituted hydrocarbon group having 2 to 20 carbon atoms and having an SH group; R T2 are each independently at least one hydrocarbon group selected from a substituted or unsubstituted hydrocarbon group having 2 to 20 carbon atoms and an SH group, and a substituted or unsubstituted hydrocarbon group having 2 to 20 carbon atoms and a polymerizable double bond, and in this case, at least two R T2 is a substituted or unsubstituted hydrocarbon group having 2 to 20 carbon atoms and an SH group; [Effects of the Invention]

[0014] According to the present invention, it is possible to provide an optical material having high transparency and high heat resistance, and also to provide a material and a composition which provides the same, which have a reduced odor characteristic of thiol-containing materials. DETAILED DESCRIPTION OF THE INVENTION

[0015] 1.Curable composition A curable composition according to one embodiment of the present invention contains a double-decker silsesquioxane (A) having two or more SH groups, represented by the formula (A1) or (A2) described below. By including the double-decker silsesquioxane (A) having two or more SH groups in the curable composition according to this embodiment, it is possible to provide an optical material having high transparency and high heat resistance. Furthermore, it is possible to provide a material and a composition which provides the material, which have a reduced odor characteristic of thiol-containing materials.

[0016] In this specification, the term "SH group" refers to a functional group also known as a thiol or sulfanyl group. Furthermore, the term "curable material" refers to a material in which a polymerizable compound in the composition is polymerized and cured by light or heat to form a cured film. Among curable materials, photocurable materials are suitable for practical use because they consume little energy during curing and are easy to form patterned films. However, the curable composition of the present invention can also be made into a thermosetting material by selecting a curing agent. It can also be cured by using both light and heat. Even when a curable material made from the curable composition of the present invention is obtained from such a thermosetting composition, it can exhibit the excellent properties described above.

[0017] If necessary, a compound (B) having two or more polymerizable double bonds can be added to the composition of the present invention. A polymerizable double bond refers to a carbon-carbon double bond capable of reacting with an SH group. The SH group and the polymerizable double bond undergo a thiol-ene reaction that proceeds rapidly upon irradiation with light, preferably in the presence of a photoradical polymerization initiator. Materials using such a thiol-ene reaction exhibit a small degree of cure shrinkage. Furthermore, they are less susceptible to oxygen inhibition during curing, allowing them to be cured in air. Therefore, it is preferable that the curable composition of the present invention be one that uses a thiol-ene reaction for curing. Meanwhile, in order to promote the polymerization reaction and improve heat resistance, it is also preferable to perform the curing under a nitrogen gas flow.

[0018] 1-1. Double-decker silsesquioxanes having two or more SH groups (A) The double-decker silsesquioxane (A) having two or more SH groups (hereinafter sometimes referred to as "double-decker silsesquioxane (A)," "component (A)," etc.) is a compound in which two or more SH groups are substituted on a double-decker silsesquioxane skeleton, and the number of SH groups is not particularly limited. The number of SH groups in the double-decker silsesquioxane (A) is preferably 2 to 6, and more preferably 2 to 4. Examples of the double-decker silsesquioxane (A) include compounds represented by the following formula (A1) or formula (A2). One type of double-decker silsesquioxane (A) may be used alone, or two or more types may be used in any combination and ratio.

[0019] TIFF2025187239000005.tif3572 TIFF2025187239000006.tif3582

[0020] In formulas (A1) and (A2), R T1 are each independently a substituted or unsubstituted hydrocarbon group having 2 to 20 carbon atoms and an SH group, and R T2 are each independently at least one hydrocarbon group selected from a substituted or unsubstituted hydrocarbon group having 2 to 20 carbon atoms and having an SH group, and a substituted or unsubstituted hydrocarbon group having 2 to 20 carbon atoms and having a polymerizable double bond, and in this case, at least two or more R T2 is a substituted or unsubstituted hydrocarbon group having 2 to 20 carbon atoms and having an SH group.

[0021] R T1 and R T2 In the above, the hydrocarbon group includes an aliphatic hydrocarbon group and an aromatic hydrocarbon group. The aliphatic hydrocarbon group is not limited to a linear one, and may have a branched structure or a cyclic structure. The aromatic hydrocarbon group may be a monocyclic, polycyclic, or fused ring type, or may be a heterocyclic aromatic hydrocarbon group. Also R T1 and R T2 In the above formula, when the hydrocarbon group has a substituent, the number of carbon atoms in the hydrocarbon group includes the number of carbon atoms in the substituent.

[0022] R T1 and R T2 In the formula (I), at least one -CH2CH2- of the hydrocarbon group not adjacent to the SH group is -OSi(R 4 )2-, in which case R 4 represents a substituted or unsubstituted hydrocarbon group having 1 to 6 carbon atoms.

[0023] R T1 and R T2 In the above, the number of SH groups in the substituted or unsubstituted hydrocarbon group having 2 to 20 carbon atoms and having an SH group is not particularly limited, but is preferably 1 from the viewpoint of ease of synthesis.

[0024] R T1 and R T2 In the above, the substituted or unsubstituted hydrocarbon group having 2 to 20 carbon atoms and having an SH group is preferably an aliphatic hydrocarbon group in order to rapidly proceed with the thiol-ene reaction. For the same reason, the carbon atom to which the SH group is bonded is preferably -CH2-. Furthermore, the number of carbon atoms in the substituted or unsubstituted hydrocarbon group having 2 to 20 carbon atoms and having an SH group is preferably 2 to 16, more preferably 2 to 12, and even more preferably 2 to 8, in order to facilitate synthesis.

[0025] R T1 and R T2 In the above, particularly suitable examples of the substituted or unsubstituted hydrocarbon group having 2 to 20 carbon atoms and having an SH group include -CH2CH2SH, -CH2CH2CH2SH, -OSi(CH3)2OSi(CH3)2CH2CH2SH, and the like.

[0026] In formulas (A1) and (A2), R 1 , R 2 , and R 3are each independently a substituted or unsubstituted hydrocarbon group having 1 to 20 carbon atoms. Examples of such hydrocarbon groups include aliphatic hydrocarbon groups, alkyls such as methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, isobutyl, n-pentyl, isopentyl, neopentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, n-tridecyl, n-tetradecyl, n-pentadecyl, n-hexadecyl, n-heptadecyl, n-octadecyl, n-nonadecyl, and n-docosyl, and cycloalkyls such as cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl.

[0027] R 1 , R 2 , and R 3 Examples of the hydrocarbon group represented by the formula (I) include aromatic hydrocarbon groups such as phenyl (-Ph), 1-naphthyl, 2-naphthyl, 1-phenanthryl, 2-phenanthryl, 3-phenanthryl, 4-phenanthryl, 9-phenanthryl, 1-anthryl, 2-anthryl, 9-anthryl, 1-pyrenyl, 2-pyrenyl, 4-pyrenyl, 1-triphenylenyl, 2-triphenylenyl, 2-triazinyl, 2-pyridyl, 3-pyridyl, 4-pyridyl, and 2-pyrazinyl.

[0028] Among these hydrocarbon groups, it is preferable to select an aromatic hydrocarbon group in order to improve the refractive index of the optical material. There is no particular limitation on the aromatic hydrocarbon group, but phenyl is more preferable because the compound can be easily synthesized. For the same reason, R 1 The hydrocarbon group represented by the formula (I) is most preferably phenyl.

[0029] R 2 and R 3 It is also preferable that the hydrocarbon group represented by the formula (I) is an aliphatic hydrocarbon group. As such an aliphatic hydrocarbon group, a short-chain hydrocarbon group such as methyl or ethyl is preferred because it allows for easy synthesis of the compound.

[0030] Above R T1 , R T2 , R 1 , R 2 , and R 3 is the R of one molecule of double-decker silsesquioxane (A). T1 , R T2 , R 1 , R 2 , and R 3 However, because of the ease of compound synthesis, R T1 , R T2 , R 1 , R 2 , and R 3 Preferably, each of the same symbols selects the same structure.

[0031] Particularly preferred double-decker silsesquioxanes (A) include compounds represented by the following A11, A21 and A22. A11: In formula (A1), all R 1 is -Ph, and two R T1 is -CH2CH2SH. A21: In formula (A1), all R 1 is -Ph and there are 2 to 4 R T1 is -CH2CH2SH, and 0 to 2 R T1 is -CH=CH2. A22: In formula (A1), all R 1 is -Ph and there are 2 to 4 R T1 is -CH2CH2CH2SH, and 0 to 2 R T1 is -CH2CH=CH2.

[0032] The double-decker silsesquioxane (A) of the present invention can be produced from a compound having a double bond produced by the method described in International Publication No. 2003 / 024870, for example, according to a known method described in "The Chemistry of Functional Groups, The Chemistry of the Thiol Group," JOHN WILEY & SONS, 1974. The synthesis of the double-decker silsesquioxane (A) will be described in detail in the following examples.

[0033] In the curable composition of the present invention, the content of the double-decker silsesquioxane (A) is not particularly limited, but from the viewpoints of transparency and heat resistance, it is preferably 1% by mass to 50% by mass, more preferably 5% by mass to 30% by mass, and even more preferably 10% by mass to 30% by mass, based on the total amount of the curable composition. In this case, in order to impart the high durability that is a feature of the present invention to the material, the content of the double-decker silsesquioxane (A) in the curable composition of the present invention is preferably 50 mol % or more, more preferably 70 mol % or more, based on the total amount of all polyfunctional thiol compounds including the double-decker silsesquioxane (A).

[0034] 1-2. Compound (B) having two or more polymerizable double bonds If necessary, the curable composition of the present invention can contain a compound (B) having two or more polymerizable double bonds (hereinafter, sometimes referred to as "component (B)"). Component (B) is not particularly limited as long as it is a compound having two or more polymerizable double bonds per molecule. The number of polymerizable double bonds contained in component (B) is usually 2 to 10, preferably 2 to 6, and more preferably 2 to 4, in view of availability. Component (B) may be used singly or in any combination and ratio of two or more.

[0035] Any known compound having the above-mentioned characteristics can be used as component (B), including, for example, esters of polyols such as ethylene glycol, tetramethylene glycol, trimethylolpropane, pentaerythritol, dipentaerythritol, polymethylene glycol, polyethylene glycol, and polypropylene glycol with polymerizable double bond-containing carboxylic acids such as acrylic acid and methacrylic acid; alkenyl ethers such as vinyl ethers, allyl ethers, and butenyl ethers of the above polyols; polymerizable double bond-containing isocyanurates such as tri(acryloyloxyethyl)isocyanurate, tri(methacryloyloxyethyl)isocyanurate, and triallyl isocyanurate; alkenyl acrylates such as vinyl acrylate and allyl acrylate; alkenyl methacrylates such as vinyl methacrylate and allyl methacrylate; and aromatic vinyls such as divinylbenzene and trivinylbenzene.

[0036] Specific compounds of component (B) include ether compounds having a polymerizable double bond, such as diallyl ether, diallyl sulfide, diallylamine, 2,4-diamino-6-diallylamino-1,3,5-triazine, glycerol-α,α'-diallyl ether, triallyl cyanurate, 1,2,4-trivinylcyclohexane, 1,5-hexadiene, divinyl sulfone, triallyl isocyanurate, triallylamine, divinylbenzene, 2,2-bis(allyloxymethyl)-1-butanol, diethylene glycol divinyl ether, and triethylene glycol divinyl ether; siloxane-based compounds having a polymerizable double bond, such as 1,3-divinyltetramethyldisiloxane, 2,4,6,8-tetramethyl-2,4,6,8-tetravinylcyclotetrasiloxane, 1,3-divinyl-1,1,3,3-tetramethyldisilazane, 2,4,6-trimethyl-2,4,6-trivinylcyclotrisiloxane, and compounds represented by the following formulas (B1) and (B2): TIFF2025187239000007.tif4177 (wherein m, n, p, and q are integers from 0 to 100, and m+n and q are 2 or more.)

[0037] ester compounds having a polymerizable double bond, such as divinyl adipate, diallyl 1,4-cyclohexanedicarboxylate, diethyl diallylmalonate, diallyl isophthalate, diallyl phthalate, triallyl 1,3,5-benzenetricarboxylate, diallyl terephthalate, diallyl maleate, diallyl adipate, and triallyl phosphate;

[0038] Allyl (meth)acrylate, 1,3-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, nonamethylene glycol di(meth)acrylate, decamethylene glycol di(meth)acrylate, 1,4-bis(acryloyl)piperazine, 4,4'-isopropylidenediphenol di(meth)acrylate, diethylene glycol di(meth)acrylate, dipentaerythritol hexa(meth)acrylate, ethylene glycol di(meth)acrylate, 2-[5-[((meth)acryloyloxy)methyl]-5-ethyl-1,3-dioxan-2-yl]-2-methylpropyl (meth)acrylate, (meth)acrylic compounds which are acrylic or methacrylic compounds having a polymerizable double bond, such as triethylene glycol dimethacrylate, 1,12-dodecanediol dimethacrylate, glycerol di(meth)acrylate, neopentyl glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, tetraethylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, tricyclodecane dimethanol di(meth)acrylate, 1-(acryloyloxy)-3-(methacryloyloxy)-2-propanol, and dipropylene glycol di(meth)acrylate; etc.

[0039] As component (B), for example, double-decker silsesquioxanes having a polymerizable double bond as described in WO 2022 / 239271 and WO 2003 / 024870 can also be used. In these specifically exemplified compounds of component (B), it is preferable to use a siloxane compound having a polymerizable double bond or a double-decker silsesquioxane in order to improve the transparency and heat resistance of the material.

[0040] In the curable composition according to this embodiment, the content of component (B) is not particularly limited. From the viewpoint of photocurability, it is preferable that the number of thiol functional groups in the double-decker silsesquioxane (A) and the number of polymerizable double bonds in component (B) match. Alternatively, from the viewpoint of reducing coloration of the material, the number of polymerizable double bonds in component (B) is preferably 80 to 120 mol %, more preferably 95 to 105 mol %, relative to the number of thiol functional groups in the double-decker silsesquioxane (A).

[0041] 1-3. Organic solvents (C) The curable composition according to this embodiment may further contain an organic solvent (C) (hereinafter, sometimes referred to as "component (C)"). The organic solvent (C) is preferably one that can dissolve the double-decker silsesquioxane (A) and component (B). Examples of the organic solvent (C) include hydrocarbon solvents (e.g., hexane, benzene, and toluene), ether solvents (e.g., diethyl ether, tetrahydrofuran (THF), 2-methyltetrahydrofuran, diphenyl ether, anisole, dimethoxybenzene, and cyclopentyl methyl ether (CPME)), halogenated hydrocarbon solvents (e.g., methylene chloride, chloroform, and chlorobenzene), ketone solvents (e.g., acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, and cyclopentanone), alcohol solvents (e.g., methanol, ethanol, propanol, isopropanol, n-butyl alcohol, and tert-butyl alcohol), nitrile solvents (e.g., acetonitrile, propionitrile, and benzonitrile), and ester solvents (e.g., ethyl acetate and butyl acetate). Examples of the organic solvent (C) include carbonate solvents (e.g., ethylene carbonate and propylene carbonate), amide solvents (e.g., N,N-dimethylformamide, N,N-dimethylacetamide, and N-methylpyrrolidone), hydrochlorofluorocarbon solvents (e.g., HCFC-141b and HCFC-225), hydrofluorocarbon (HFCs) solvents (e.g., HFCs having 2 to 6 carbon atoms), perfluorocarbon solvents (e.g., perfluoropentane and perfluorohexane), alicyclic hydrofluorocarbon solvents (e.g., fluorocyclopentane and fluorocyclobutane), oxygen-containing fluorine-containing solvents (e.g., fluoroethers, fluoropolyethers, fluoroketones, and fluoroalcohols), and aromatic fluorine-containing solvents (e.g., α,α,α-trifluorotoluene and hexafluorobenzene). The organic solvent (C) may be used alone or in any combination and ratio of two or more.

[0042] When the curable composition according to the present embodiment contains an organic solvent (C), the content of the organic solvent (C) is preferably adjusted appropriately depending on the method for applying the curable composition to a substrate, the desired thickness of the cured film, and the like. For example, to improve the flatness and other properties of the cured film, the content of the organic solvent (C) is preferably 50% by mass to 95% by mass, and more preferably 70% by mass to 95% by mass, based on the total amount of the curable composition. On the other hand, when a long time or high temperature is required to remove the organic solvent (C), or when there is a possibility that the amount of solvent remaining in the cured film will increase, the content of the organic solvent (C) is preferably 30% by mass or less, and more preferably 20% by mass or less, based on the total amount of the curable composition.

[0043] 1-4. Polymerization initiator The curable composition according to this embodiment preferably contains a polymerization initiator to promote curing. Such a polymerization initiator can be selected from known radical polymerization initiators, cationic polymerization initiators, and anionic polymerization initiators. To improve the heat resistance of the curable composition to be cured and other components used simultaneously, it is preferable to select a radical polymerization initiator or an anionic polymerization initiator as the polymerization initiator. From the viewpoint of promoting polymerization, it is more preferable to select a radical polymerization initiator. Depending on the desired curing conditions, the polymerization initiator can be selected from a photopolymerization initiator, a thermal polymerization initiator, or a combination of these.

[0044] The photoradical polymerization initiator that can be suitably used in the curable composition according to this embodiment is preferably an alkylphenone-based photopolymerization initiator, an acylphosphine oxide-based photopolymerization initiator, or an oxime ester-based photopolymerization initiator, and from the viewpoint of good wet heat durability, the oxime ester-based photopolymerization initiator is particularly preferred.

[0045] Examples of alkylphenone photopolymerization initiators include 1-hydroxycyclohexylphenyl ketone, 2-hydroxy-1-{4-[4-(2-hydroxy-2-methylpropionyl)benzyl]phenyl}-2-methylpropan-1-one, and 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one. Commercially available products such as Omnirad 184, Omnirad 127, Omnirad 907, Omnirad 369, and Omnirad 379 may also be used. Omnirad is a trademark of IGM Resins BV.

[0046] Examples of acylphosphine oxide photopolymerization initiators include bis-(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, and commercially available products such as Omnirad TPO and Omnirad 819 may be used. Omnirad is a trademark of IGM Resins BV.

[0047] Examples of oxime ester photopolymerization initiators include 1,2-octanedione, 1-[4-(phenylthio)-, 2-(O-benzoyloxime)], ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-, 1-(O-acetyloxime), and the like. Commercially available products such as IrgacureOXE01, IrgacureOXE02, IrgacureOXE03, IrgacureOXE04, Adeka Arcles N-1919, Adeka Arcles NCI-831, Adeka Arcles NCI-930, and Adeka Arcles NCI-730 may also be used. Here, Irgacure is a trademark of BASF Japan, and Adeka Arcles is a trademark of ADEKA Corporation.

[0048] The content of the polymerization initiator is preferably 0.1% by mass to 9% by mass relative to the total amount of the curable composition so as to rapidly proceed with the curing of the curable composition and not reduce the durability of the cured film. Furthermore, the content is preferably 1% by mass to 10% by mass relative to the total amount of solids in the curable composition. The solid content refers to the solid portion of the curable composition excluding volatile components such as organic solvents, and is the non-volatile content.

[0049] 1-5.Other ingredients The curable composition according to this embodiment may contain various additives to improve coating uniformity and adhesion between the cured film and the substrate when applied to a substrate and cured to form a cured film. The substrate is not particularly limited, and glass, metal, plastic, paper, fiber, and the like can be suitably used. Examples of additives include surfactants (leveling agents); adhesion improvers such as silane coupling agents; antioxidants; molecular weight modifiers; ultraviolet absorbers; anti-aggregation agents; and water.

[0050] 1-5-1. Compounds with two or more SH groups other than double-decker silsesquioxane (A) In the curable composition of the present invention, the double-decker silsesquioxane (A) may be used in combination with a known polyfunctional thiol compound other than component (A) as a compound having two or more SH groups other than component (A). The number of SH groups in such known polyfunctional thiol compounds is preferably 2 to 8, more preferably 2 to 6, and even more preferably 2 to 4, because they are easily available and have good curability.

[0051] Specific examples of such polyfunctional thiol compounds include trimethylolpropane tris(thioglycolate), pentaerythritol tetrakis(thioglycolate), ethylene glycol bis(thioglycolate), tetraethylene glycol bis(3-mercaptopropionate), trimethylolpropane tris(3-mercaptopropionate), pentaerythritol tetrakis(3-mercaptopropionate), dipentaerythritol poly(3-mercaptopropionate), trimethylolpropane tris(3-mercaptopropyl)ether, pentaerythritol tetrakis(3-mercaptopropyl)ether, ethylene glycol bis(2-mercaptoethyl)ether, tetraethylene glycol bis(2-mercaptoethyl)ether, 1,4-butanedithiol, 1,6-hexanedithiol, 1,10-decanedithiol, Multhiol Y-3, and Multhiol Y-4 (all trade names, manufactured by SC Organic Chemical Co., Ltd.) and the like.

[0052] These polyfunctional thiol compounds may be used alone or in any combination and ratio of two or more. However, in order to improve the transparency and heat resistance of the material, the content of the above polyfunctional thiol is preferably 70 mol% or less, more preferably 50 mol% or less, based on the total amount of all polyfunctional thiol compounds including the double-decker silsesquioxane (A). It is most preferable not to use the above polyfunctional thiol in combination.

[0053] 1-5-2.Surfactants The curable composition according to the present embodiment preferably contains a surfactant from the viewpoint of improving the wettability, leveling property, or coatability of the curable composition on a substrate. The surfactant may be used alone or in any combination and ratio of two or more kinds.

[0054] Examples of surfactants include Polyflow No. 45, Polyflow KL-245, Polyflow No. 75, Polyflow No. 90, and Polyflow No. 95 (all trade names; manufactured by Kyoeisha Chemical Co., Ltd.); Disperbyk 161, Disperbyk 162, Disperbyk 163, Disperbyk 164, Disperbyk 166, Disperbyk 170, Disperbyk 180, Disperbyk 181, Disperbyk 182, BYK300, BYK306, BYK310, BYK320, and BYK 330, BYK342, BYK346, BYK-UV3500, and BYK-UV3570 (all trade names, manufactured by BYK Japan Co., Ltd.); KP-341, KP-358, KP-368, KF-96-50CS, and KF-50-100CS (all trade names, manufactured by Shin-Etsu Chemical Co., Ltd.); Surflon SC-101 and Surflon KH-40 (all trade names, manufactured by AGC Seimi Chemical Co., Ltd.); Ftergent 222F, Ftergent 251, and FTX-218 (all trade names, manufactured by Neos Co., Ltd.); EFTOP EF-351, EFTOP EF-352, EFTOP EF-601, EFTOP EF-801, and EFTOP EF-802 (all trade names, manufactured by Mitsubishi Materials Corporation); Megafac (registered trademark) F-410, Megafac (registered trademark) F-430, Megafac (registered trademark) F-444, Megafac (registered trademark) F-472SF, Megafac (registered trademark) F-475, Megafac (registered trademark) F-477, Megafac (registered trademark) F-552, Megafac (registered trademark) F-553, Megafac (registered trademark) F-554, Megafac (registered trademark) F-555, Megafac (registered trademark) F-556, Megafac (registered trademark) F-558, Megafac (registered trademark) F-563, Megafac (registered trademark) R-94, Megafac (registered trademark) RS-75, and Megafac (registered trademark) RS-72-K (all trade names, manufactured by DIC Corporation); TEGO Rad Preferred examples include commercially available products such as 2200N and TEGO Rad 2250N (trade names, manufactured by Evonik Degussa Japan Co., Ltd.); and Silaplane (registered trademark) FM-0511 (trade name, manufactured by JNC Corporation).

[0055] When the curable composition according to this embodiment contains a surfactant, the content of the surfactant is preferably 0.01 to 10% by mass relative to the total amount of the curable composition.

[0056] 1-5-3. Coupling agents The curable composition according to the present embodiment preferably contains a coupling agent as an adhesion improver, from the viewpoint of improving the adhesion between a cured film formed from the curable composition and a substrate. The coupling agent may be used alone or in any combination and ratio of two or more types.

[0057] Examples of coupling agents that can be used include silane-based, aluminum-based, and titanate-based compounds. Specific examples of coupling agents include silane-based coupling agents such as vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropyldimethylethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-methacryloxypropyltrimethoxysilane, and 3-methacryloxypropyltriethoxysilane; aluminum-based coupling agents such as acetoalkoxyaluminum diisopropylate; and titanate-based coupling agents such as tetraisopropylbis(dioctylphosphite)titanate. Among these, 3-glycidoxypropyltrimethoxysilane is preferred due to its significant effect of improving adhesion. Examples of commercially available coupling agents include Sila Ace S510 (trade name, manufactured by JNC Corporation) and Sila Ace S530 (trade name, manufactured by JNC Corporation).

[0058] When the curable composition according to this embodiment contains an adhesion improver, the content of the adhesion improver is preferably 0.01% by mass to 10% by mass relative to the total amount of the curable composition.

[0059] 1-5-4. Antioxidants The curable composition according to the present embodiment preferably further contains an antioxidant from the viewpoint of improving the transparency of the cured film and preventing yellowing of the cured film when exposed to high temperatures. The antioxidants may be used alone or in any combination and ratio of two or more.

[0060] Examples of the antioxidant include hindered phenol-based antioxidants, hindered amine-based antioxidants, phosphorus-based antioxidants, and sulfur-based antioxidants, and from the viewpoint of heat resistance, hindered phenol-based antioxidants are preferred. Specific examples of antioxidants include Irganox1010, Irganox1010FF, Irganox1035, Irganox1035FF, Irganox1076, Irganox1076FD, Irganox1098, Irganox1135, Irganox1330, Irganox1726, Irganox1425WL, Irganox1520L, Irganox245, Irganox245FF, Irganox259, Irganox3114, Irganox565, and Irganox565DD (all trade names, manufactured by BASF Japan Ltd.); and ADK STAB AO-20, ADK STAB AO-30, ADK STAB AO-50, ADK STAB AO-60, and ADK STAB AO-80 (both trade names, manufactured by ADEKA Corporation); etc. Among these, preferred antioxidants are Irganox 1010 and ADK STAB AO-60.

[0061] When the curable composition according to this embodiment contains an antioxidant, the content of the antioxidant is preferably 0.1% by mass to 5% by mass relative to the total amount of the curable composition.

[0062] 1-5-5. Molecular weight regulator The curable composition according to the present embodiment may contain a molecular weight modifier in order to maintain storage stability. The molecular weight modifier may be used alone or in any combination and ratio of two or more kinds.

[0063] Examples of molecular weight modifiers include mercaptans (excluding those corresponding to double-decker silsesquioxane (A) and polyfunctional thiol compounds other than component (A)), xanthogens, quinones, and hydroquinones. Specific examples of the molecular weight modifier include 1,4-naphthoquinone, 1,2-benzoquinone, 1,4-benzoquinone, methyl-p-benzoquinone, anthraquinone, hydroquinone, methylhydroquinone, tert-butylhydroquinone, 2,5-di-tert-butylhydroquinone, 2,5-di-tert-amylhydroquinone, 1,4-dihydroxynaphthalene, 3,6-dihydroxybenzonol bornane, 4-methoxyphenol, 2,2',6,6'-tetratert-butyl-4,4'-dihydroxybiphenyl, 3-(3,5-di-tert-butyl-4-hydroxyphenyl)stearyl propionate, 2,2'-methylenebis(6-tert-butyl-4-ethylphenol), 2,4,6-tris(3',5'-di-tert-butyl-4 4,4'-butylidenebis(6-tert-butyl-m-cresol), 4,4'-thiobis(6-tert-butyl-m-cresol), 2,4-diphenyl-4-methyl-1-pentene, phenothiazine, and 2-hydroxy-1,4-naphthoquinone. Among these, the molecular weight modifier is preferably a naphthoquinone-based molecular weight modifier, and more preferably 2-hydroxy-1,4-naphthoquinone, from the viewpoint of exhibiting excellent storage stability. When the curable composition according to the present embodiment contains a molecular weight modifier, the content of the molecular weight modifier is preferably 0.01% by mass to 1% by mass based on the total amount of the curable composition.

[0064] 1-5-6. UV absorbers The curable composition according to the present embodiment may contain an ultraviolet absorber in order to prevent a decrease in the transparency of the cured film formed by curing. The ultraviolet absorbers may be used alone or in any combination and ratio of two or more.

[0065] Specific examples of the ultraviolet absorber include TINUVIN P, TINUVIN 120, TINUVIN 144, TINUVIN 213, TINUVIN 234, TINUVIN 326, TINUVIN 571, and TINUVIN 765 (all trade names; manufactured by BASF Japan Ltd.).

[0066] When the curable composition according to this embodiment contains an ultraviolet absorber, the content of the ultraviolet absorber is preferably 0.01% by mass to 10% by mass relative to the total amount of the curable composition.

[0067] 1-5-7. Anti-aggregating agents When the curable composition according to the present embodiment contains an organic solvent (C), it may contain an anti-aggregation agent from the viewpoint of preventing aggregation by making the double-decker silsesquioxane (A), and the component (B) and other components contained as needed compatible with the organic solvent (C). The anti-aggregation agent may be used alone, or two or more types may be used in any combination and ratio.

[0068] Specific examples of anti-agglomerating agents include DISPERBYK-145, DISPERBYK-161, DISPERBYK-162, DISPERBYK-163, DISPERBYK-164, DISPERBYK-182, DISPERBYK-184, DISPERBYK-185, DISPERBYK-2163, DISPERBYK-2164, BYK-220S, DISPERBYK-191, DISPERBYK-199, and DISPERBYK-2015 (all trade names; manufactured by BYK-Chemie Japan KK); FTX-218, Ftergent 710FM, and Ftergent 710FS (all trade names; manufactured by Neos Corporation); Floren G-600 and Floren G-700 (all trade names; manufactured by Kyoeisha Chemical Co., Ltd.); and the like.

[0069] When the curable composition according to this embodiment contains an anti-aggregating agent, the content of the anti-aggregating agent is preferably 0.01% by mass to 10% by mass relative to the total amount of the curable composition.

[0070] In the curable composition of the present invention, the content of the above-mentioned surfactant, coupling agent, antioxidant, molecular weight modifier, UV absorber, anti-aggregation agent, etc. is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, relative to the sum of the masses of component (A) of the present invention or the mixture of component (A) and the polyfunctional thiol compound, and component (B), in order to maintain the transparency and heat resistance of the material.

[0071] 1-6. Storage of curable composition The curable composition according to this embodiment is preferably stored in a temperature range of −30 to 25° C., since the curable composition has good stability over time. A storage temperature of −20 to 10° C. is more preferable, since no precipitates are generated.

[0072] 2. Cured film obtained from the curable composition The curable composition according to this embodiment can be obtained by mixing a double-decker silsesquioxane (A) having two or more polymerizable double bonds, and, if necessary, a component (B), an organic solvent (C), and other components.

[0073] When the curable composition prepared as described above is in the form of a solution, it can be used as a varnish to produce a cured film as it is, and when it is not in the form of a solution, an organic solvent (C) can be further added to the prepared curable composition to form a solution, which can be used as a varnish to produce a cured film. For example, this varnish can be irradiated with light and then applied to the surface of a substrate to obtain a coating film, or the varnish can be applied to the surface of a substrate and the resulting coating film can be irradiated with light, and then the coating film can be dried (pre-baked) by, for example, heating, and if necessary, baked to further promote the curing reaction, thereby forming a cured film of the curable composition.

[0074] Examples of light irradiated onto the varnish include ultraviolet light. UV irradiation onto the varnish can be carried out by known methods, such as using a high-pressure mercury lamp, an ultraviolet light-emitting diode (LED), a low-pressure mercury lamp, or a spot UV irradiation device. Because the curable composition of the present invention is not susceptible to oxygen inhibition during curing, photocuring can also be carried out in the air. However, photocuring is preferably carried out in a nitrogen atmosphere to increase the reaction rate. The varnish can be applied to the surface of a substrate by conventional methods, such as drop casting, spin coating, roll coating, dipping, bar coating, slit coating, and application using a dispenser.

[0075] The resulting coating film is then pre-baked on a hot plate or oven. The pre-baking conditions vary depending on the type and blending ratio of each component, but are typically at a temperature of 70 to 100°C for 5 to 15 minutes in an oven or 1 to 5 minutes on a hot plate. If necessary, the coating film is then baked to harden. The baking conditions vary depending on the type and blending ratio of each component, but are typically at a temperature of 80 to 150°C, preferably 90 to 130°C, for 10 to 90 minutes in an oven or 5 to 30 minutes on a hot plate. A cured film can be obtained by heat treatment.

[0076] If necessary, the light irradiation and heating steps can be performed simultaneously or in the reverse order to form a cured film. The cured film obtained in this manner has excellent heat resistance and light resistance, and can maintain its performance for a long period of time during use. In a preferred aspect of this embodiment, the cured film has high transparency from visible light to the near-infrared region. Furthermore, by changing the selection of the double-decker silsesquioxane (A) and component (B), the refractive index of the cured film can be adjusted over a wide range. Therefore, the cured film obtained from the curable composition according to this embodiment is particularly suitable for use as an optical material such as an optical waveguide material or a protective film for a light-emitting element. [Example]

[0077] EXAMPLES Next, the present invention will be specifically explained with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples in any way.

[0078] The compounds used in the examples and comparative examples will be explained below. <Component (A): Double-decker silsesquioxane> Two compounds represented by the following formulae (A11-1) and (A21-1) were used. The compound represented by formula (A21-1) was used as a mixture. The synthesis of these compounds will be described in detail in the Examples. TIFF2025187239000008.tif3596 TIFF2025187239000009.tif3587 (in formula (A21-1), R T2 is -CH2CH2SH or -CH=CH2, the number of -CH2CH2SH is an integer of 2 to 4, and the number of -CH=CH2 is an integer of 2 to 0.)

[0079] <Component (B): Compound Having Two or More Polymerizable Double Bonds> 1,3-Divinyltetramethyldisiloxane, 2,4,6,8-tetramethyl-2,4,6,8-tetravinylcyclotetrasiloxane, and 2,4,6-trimethyl-2,4,6-trivinylcyclotrisiloxane (manufactured by Tokyo Chemical Industry Co., Ltd.) were purchased and used as is as component (B). In the following examples, 1,3-divinyltetramethyldisiloxane will be abbreviated as DVTMDS, 2,4,6,8-tetramethyl-2,4,6,8-tetravinylcyclotetrasiloxane as TetVCTS, and 2,4,6-trimethyl-2,4,6-trivinylcyclotrisiloxane as TriVCTS. 2,12-Diallyl ether dinaphthothiophene (abbreviation: DAODNT) was used as is. Triallyl isocyanurate (trade name "TAIC" manufactured by Mitsubishi Chemical Corporation) was used as is.

[0080] <Component (C): Organic solvent> Tetrahydrofuran (THF, Fujifilm Wako Pure Chemical Industries, Ltd.) was used as is.

[0081] <Polymerization initiator> Adeka Arcles NCI-930 (trade name, manufactured by ADEKA Corporation) was used as is. Bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide (trade name "Omnirad819" manufactured by IGM Resins BV) <Polymerization inhibitor> N-nitrosophenylhydroxylamine aluminum salt (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., trade name "Q-1301") was used as is.

[0082] <Compounds containing an SH group other than double-decker silsesquioxane (A)> Multhiol Y-4 (trade name): 3-{3-(3-mercaptopropoxy)-2,2-bis[(3-mercaptopropoxy)methyl]propoxy}-1-propanethiol, manufactured by SC Organic Chemical Co., Ltd., was used as is. 1,8-Dimercapto-3,6-dioxaoctane (trade name "DMDO" manufactured by Maruzen Petrochemical Co., Ltd.)

[0083] <NMR Measurement> NMR was measured using an FT-NMR instrument (JNM-ECZ500R) manufactured by JEOL Ltd. 1 The magnetic field strength in 1H-NMR measurement was 500 MHz. The sample was dissolved in a deuterated solvent such as CDCl3, and the measurement was carried out at room temperature. At this time, the number of integration times was 32. As the internal standard, CHCl3 in CDCl3 or tetramethylsilane was used. Among the NMR notations, s means singlet, d means doublet, t means triplet, m means multiplet, and br means broad.

[0084] <000​​​​​​​​​​​​​​​​​​​​​​​​​​A mixture of 4.0 g (3.3 mmol) of the compound represented by formula (A11-1a), 0.80 mL (11 mmol) of thioacetic acid, and 0.82 g (5.0 mmol) of 2,2-azobisisobutyronitrile was reacted in 20 mL of toluene under a nitrogen atmosphere at 100°C for 2 hours. After cooling, the reaction mixture was added with 30 mL of toluene and washed twice with 10% aqueous sodium bicarbonate (50 mL) and purified water (50 mL). After drying over anhydrous MgSO4, the mixture was filtered, and the solvent was removed under reduced pressure. The residue was purified by column chromatography (toluene / ethyl acetate = 20 / 1 (volume ratio)) to obtain the compound represented by formula (A11-1b). Yield: 4.5 g (stoichiometric). This compound contained structural isomers, but was used directly in the next reaction.

[0089] 4.5 g (3.3 mmol) of the compound represented by formula (A11-1b) was added to 47 ml of a 16% hydrogen chloride-cyclohexyl methyl ether solution, followed by the addition of ethanol (23 ml) and refluxing for 2 hours. After cooling the reaction mixture, 30 ml of toluene was added and the mixture was washed with 10% aqueous sodium bicarbonate (50 ml) and purified water (40 ml). After drying over anhydrous MgSO4, the mixture was filtered and the solvent was removed under reduced pressure. The residue was purified by column chromatography (toluene) to obtain the compound represented by formula (A11-1). This compound contained structural isomers. Yield: 3.9 g (93%).

[0090] 1 H-NMR(ppm,CDCl3);7.53-7.20(m,40H),2.76-2.63(m,4H),1.43-1.35(m,2H),1.20-1.15(m,4H),0.41,0.33(s,6H).

[0091] [Example 2] Synthesis of double-decker silsesquioxane (A21-1) 50.2 g (43.4 mmol) of the compound represented by formula (A21-1a) and 400 ml of anhydrous THF were placed in a 500 ml three-neck flask and stirred. 31.4 g (260 mmol) of chlorodimethylvinylsilane was added dropwise to the resulting slurry (suspension) using a dropping funnel at room temperature. The reaction mixture was stirred overnight at room temperature, and then 200 ml of toluene and 200 ml of purified water were added to separate the organic layer. The organic layer was washed twice with 150 ml of purified water and then dried over anhydrous MgSO4. The mixture was filtered, the solvent was removed under reduced pressure, and the resulting residue was recrystallized from heptane to obtain the compound represented by formula (A21-1b). Yield: 60.0 g (98%). The compound represented by formula (A21-1a) was synthesized according to JP-A No. 2006-265243.

[0092] 50.0 g (35.6 mmol) of the compound represented by formula (A21-1b) and 0.24 ml (2.03 mmol) of trimethyl phosphite were added to butyl acetate (300 ml) and photoreaction was carried out at room temperature for 1 hour while supplying hydrogen sulfide to the reaction mixture. A high-pressure mercury lamp was used as the light source for the photoreaction. After purging the reactor with nitrogen gas overnight, the solvent was distilled off under reduced pressure. The residue was purified by column chromatography (toluene) to obtain the compound represented by formula (A21-1). Yield: 31 g (58%). The ratio of thiol to polymerizable double bonds in this compound was calculated as follows: 1 This was confirmed by H-NMR, and the integral ratio of the signals near 2.7 and 6.0 ppm revealed a percentage (molar ratio) of 49 / 51.

[0093] [Examples 3 to 8] (Preparation of Varnish) In Examples 3 to 8, varnishes, which are curable compositions, were prepared to have the compositions shown in Table 1. In practice, each component was placed in a glass screw tube and stirred to dissolve the components, producing a varnish. Although not shown in the table, 5.0 parts by mass of Adeka Arcles NCI-930 (trade name, manufactured by ADEKA Corporation) as a polymerization initiator was added to all varnishes, relative to 100 parts by mass of the total solid content. In the table, the content of each component is the content when the total amount of the varnish excluding the polymerization initiator is taken as 100 mass %.

[0094] (Preparation of cured film) A glass substrate was used as the substrate, and each varnish was spin-coated onto a 40 mm square, 0.5 mm thick Eagle XG (registered trademark) glass substrate (manufactured by CORNING). The rotation speed of the spin coating method was 700 rpm. Each varnish was applied to the surface of the glass substrate, and the resulting coating film sample was heated at 80°C for 1 minute, and then irradiated with light under a nitrogen stream to harden the film, producing a cured film. Separately, samples were scraped off from cured films prepared with different exposure doses, and the IR signals of the thiol groups in these samples were measured. The decrease in these IR signals was examined, and the result was 3.8 J / cm 2 More than 70mW / cm 2 ) the curing reaction was completed. Therefore, the exposure dose for producing the cured film in Examples 3 to 8 was 3.8 J / cm 2 It was decided.

[0095] (Transparency Assessment) The transparency of the resulting cured film was evaluated by UV-VIS (ultraviolet-visible spectroscopy) transmittance. A transmittance of 90% or more at a wavelength of 400 nm was evaluated as ◯, and a transmittance of less than 90% was evaluated as ×.

[0096] (Evaluation of heat resistance) The resulting cured film was left in an oven at 170°C for one week, and the transparency of the film after the heat resistance evaluation was evaluated by UV-VIS transmittance. A transmittance of 70% or more at a wavelength of 400 nm was evaluated as ◯, and a transmittance of less than 70% was evaluated as ×. The results of the physical property evaluations of Examples 3 to 8 are shown in Table 1.

[0097] [Comparative Example 1] A resin composition was prepared according to Example 7 of WO 2015 / 029996. This resin composition was diluted with twice the mass of THF relative to the resin composition to prepare a varnish having the composition shown in Table 1. Although not shown in the table, 3.0 parts by mass of bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide as a polymerization initiator and 0.002 parts by mass of N-nitrosophenylhydroxylamine aluminum salt as a polymerization inhibitor were added to the varnish relative to 100 parts by mass of the total solids content. In the table, the content of each component is the content when the total amount of the varnish excluding the polymerization initiator and polymerization inhibitor is taken as 100 mass %. The varnish sample obtained above was spin-coated (at 1000 rpm) onto a 40 mm square, 0.5 mm thick Eagle XG (registered trademark) glass substrate (manufactured by Corning) in accordance with Example 7 of International Publication No. 2015 / 029996. The resulting coating film sample was heated at 80°C for 1 minute and then irradiated with light at a wavelength of 365 nm at an intensity of 30 mW / cm under a nitrogen stream. 2 , exposure amount 30J / cm 2 The resulting cured film had a thickness of 1.73 μm. The transparency of the cured film was evaluated as ◯, but the heat resistance was evaluated as ×. The results of the physical property evaluation of Comparative Example 1 are shown in Table 1.

[0098] [Table 1] TIFF2025187239000012.tif200160

[0099] As is clear from the results of Examples 3 to 8 and Comparative Example 1, the curable composition of the present invention provides a cured film upon irradiation with low-energy light, and the obtained cured film exhibits high transparency and heat resistance. As such, the composition of the present invention can be suitably used particularly for optical applications. In particular, it is extremely useful industrially as a material for elements used in high-temperature environments such as automobiles.

[0100] While the present invention has been described above with reference to specific embodiments, these embodiments are presented as examples and do not limit the scope of the present invention. That is, each embodiment described in this specification can be modified in various ways without departing from the spirit of the invention, and can be combined with features described in other embodiments to the extent possible. [Industrial Applicability]

[0101] The curable composition of the present invention has excellent properties, such as high transparency (low propagation loss), high heat resistance, and high adhesion to substrates. Therefore, it can be suitably used for optical materials, including optical waveguides. It is particularly useful industrially as a material for elements used in high-temperature environments in various vehicles, such as automobiles.

Claims

1. A curable composition comprising a double-decker silsesquioxane (A) having two or more SH groups, wherein the double-decker silsesquioxane (A) having two or more SH groups is at least one selected from the group consisting of silsesquioxanes represented by formula (A1) and formula (A2): (In formulas (A1) and (A2), R 1 , R ２ , and R ３ are each independently a substituted or unsubstituted hydrocarbon group having 1 to 20 carbon atoms; R Ｔ１ are each independently a substituted or unsubstituted hydrocarbon group having 2 to 20 carbon atoms and having an SH group; R Ｔ２ are each independently at least one hydrocarbon group selected from a substituted or unsubstituted hydrocarbon group having 2 to 20 carbon atoms and an SH group, and a substituted or unsubstituted hydrocarbon group having 2 to 20 carbon atoms and a polymerizable double bond, and in this case, at least two R Ｔ２ is a substituted or unsubstituted hydrocarbon group having 2 to 20 carbon atoms and an SH group;

2. The curable composition according to claim 1, wherein the double-decker silsesquioxane (A) having two or more SH groups is the following A11, A21, or A22: A11: In formula (A1), all R １ is -Ph, and two R Ｔ１ Ga-CH ２ CH ２ It's SH. A21; In formula (A2), all R １ is -Ph, and R Ｔ２ Ga-CH ２ CH ２ SH or -CH=CH ２ and -CH ２ CH ２ The number of SH is an integer of 2 to 4, and -CH=CH ２ is an integer between 2 and 0. A22; In formula (A2), all R １ is -Ph, and R Ｔ２ Ga-CH ２ CH ２ CH ２ SH or -CH ２ CH=CH ２ and -CH ２ CH ２ CH ２ The number of SH is an integer of 2 to 4, and —CH ２ CH=CH ２ is an integer between 2 and 0.

3. The curable composition according to claim 1 , further comprising a compound (B) having two or more polymerizable double bonds.

4. The curable composition according to any one of claims 1 to 3, further comprising an organic solvent (C).

5. A cured film obtained by curing the curable composition according to claim 1.

6. An optical material using the cured film according to claim 5.

7. A silsesquioxane represented by formula (A1) or formula (A2): (In formulas (A1) and (A2), R 1 , R ２ , and R ３ are each independently a substituted or unsubstituted hydrocarbon group having 1 to 20 carbon atoms; R Ｔ１ are each independently a substituted or unsubstituted hydrocarbon group having 2 to 20 carbon atoms and having an SH group; R Ｔ２ are each independently at least one hydrocarbon group selected from a substituted or unsubstituted hydrocarbon group having 2 to 20 carbon atoms and an SH group, and a substituted or unsubstituted hydrocarbon group having 2 to 20 carbon atoms and a polymerizable double bond, and in this case, at least two R Ｔ２ is a substituted or unsubstituted hydrocarbon group having 2 to 20 carbon atoms and an SH group;

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