Curable composition

Abstract

To provide a curable composition that is applicable to a base material without use of a solvent and that, upon light irradiation or heating, enables formation of a cured film showing high transparency and high heat resistance.SOLUTION: A curable composition comprising the following component A and component B, and optionally comprising component C, wherein A: a compound having a diphenylsiloxane structure and having two or more polymerizable double bonds, the compound having a weight average molecular weight of 5000 or less, B: a compound having two or more thiol groups, and C: a polymerization initiator.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a curable composition, and more particularly to an ene-thiol-based curable composition using a siloxane compound and a cured film thereof. [Background technology]

[0002] Optical interconnection technology, which uses optical signals for short-distance signal transmission between or within boards in routers and server devices, is being developed to address the increasing data capacity and speed of the Internet and local area networks (LANs) and to reduce the associated increases in power consumption and heat generation. Polymer materials are ideally 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 ideally suited for use because they are easier to process than inorganic materials, allowing for greater flexibility and the wiring of high-density optical waveguides.

[0003] 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 must have a relatively high refractive index, as well as high transparency (low propagation loss), solder reflow resistance, and high adhesion to the substrate.

[0004] 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.

[0005] 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]

[0006] [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]

[0007] This application discloses a technology that overcomes the drawbacks of existing materials. Specifically, it provides a curable material that is highly transparent and maintains its properties even when exposed to high temperatures for extended periods of time. The transparency here refers to performance across the visible to near-infrared range. Furthermore, because the composition can be cured using a radical polymerization initiator, it is possible to prevent acidic substances from lurking in the material without any additional steps. Furthermore, because the composition is liquid without the use of a solvent, its use can reduce voids caused by residual solvents and shorten the takt time during the fabrication of optical elements. [Means for solving the problem]

[0008] As a result of extensive research into solving the above problems, the present inventors have found that the above problems can be solved by using the following composition disclosed in the present application, and have thus completed the present invention.

[0009] The present invention includes the following configurations. [1] A curable composition comprising the following component A and component B: A: A compound with a diphenylsiloxane structure, two or more polymerizable double bonds, and a weight-average molecular weight of 5,000 or less. B: Compounds with two or more thiol groups.

[0010] [2] The curable composition according to [1], wherein component A is a compound represented by formula (1). TIFF2025182682000001.tif37150 (In formula (1), R 1 and R 2 are each independently an alkenyl having 2 to 10 carbon atoms, methyl, or phenyl; R 1 and R 2 at least two of the above are alkenyl having 2 to 10 carbon atoms, m is an integer of 0 to 5, n is 0 or 1, and q is an integer of 1 to 5; multiple m's in the formula may be the same or different; at least one m is an integer of 1 to 5; and when there are multiple n's in the formula, they may be the same or different.

[0011] [3] The curable composition according to [1] or [2], wherein component B is a compound represented by formula (2-1). TIFF2025182682000002.tif4162 (In formula (2-1), R 3 is -CH2CH2SH or -CH2CH2CH2SH, and R 4 is methyl or phenyl, r is 1 or 2, and there are multiple R 3 or R 4 may be the same or different.)

[0012] [4] The curable composition according to [1] or [2], wherein component B is a compound represented by formula (2-2): TIFF2025182682000003.tif3264 (In formula (2-2), A is alkylene having 1 to 10 carbon atoms, one —CH— in the alkylene may be replaced with —O—, X is SH, OH, or CH, and multiple As or Xs in the formula may be the same or different, provided that at least two of the Xs are SH.)

[0013] [5] The curable composition according to [1] or [2], wherein component B is a compound represented by formula (2-3): TIFF2025182682000004.tif4062 (In formula (2-3), A 2 is alkylene having 1 to 10 carbon atoms, one —CH2— of the alkylene may be replaced by —O— or —S—, X 2 is SH or CH3, and there are multiple A 2 or X 2 may be the same or different, provided that X 2 At least two of them are SH.)

[0014] [6] The curable composition according to any one of [1] to [5], further comprising the following component C: C: Polymerization initiator.

[0015] [7] A cured film obtained by curing the curable composition according to any one of [1] to [6].

[0016] [8] An optical material using the cured film described in [7]. [Effects of the Invention]

[0017] According to the present invention, a composition that can be applied to a substrate without using a solvent can be provided, and by using this composition, optical elements that are highly transparent and have high heat resistance can be easily produced. DETAILED DESCRIPTION OF THE INVENTION

[0018] 1.Curable composition A curable composition according to one embodiment of the present invention contains the following components A and B as essential components, and optionally contains component C as an optional component. By using such a composition, a material exhibiting the above-described properties can be obtained. A: A compound having a diphenylsiloxane structure, two or more polymerizable double bonds, and a weight-average molecular weight of 5,000 or less B: Compounds with two or more thiol groups C: Polymerization initiator

[0019] 2. Ingredient A Component A is a compound having a diphenylsiloxane structure, two or more polymerizable double bonds, and a weight-average molecular weight of 5,000 or less. To obtain a composition that can be applied to a substrate without using a solvent, a feature of the present application, Component A is preferably a liquid. To make Component A a liquid, the weight-average molecular weight of Component A is preferably 5,000 or less, more preferably 3,000 or less, even more preferably 2,000 or less, and most preferably 1,000 or less. The lower limit of the weight-average molecular weight of Component A is preferably 384, and more preferably 582.

[0020] In order to improve the refractive index and heat resistance of the material, Component A has a diphenylsiloxane structure as a structural unit. In this case, in order to make Component A liquid, it is preferable that a certain proportion of siloxane structural units without phenyl groups is contained in the compound structure. From the viewpoints of improving the refractive index and heat resistance, and making Component A liquid, the content of such siloxane structural units without phenyl groups is preferably a ratio of 0.3 to 0.5, where the total number of siloxane structural units is 1.

[0021] An example of a compound suitable for Component A is a compound having a structure represented by the following formula (1). Component A may contain the compound represented by formula (1) as the main component and may also contain compounds having other structures. Component A may also contain multiple compounds represented by formula (1). TIFF2025182682000005.tif36148 (In formula (1), R 1 and R 2 are each independently an alkenyl having 2 to 10 carbon atoms, methyl, or phenyl; R 1 and R 2 at least two of the above are alkenyl having 2 to 10 carbon atoms, m is an integer of 0 to 5, n is 0 or 1, and q is an integer of 1 to 5; multiple m's in the formula may be the same or different; at least one m is an integer of 1 to 5; and when there are multiple n's in the formula, they may be the same or different. R 1 and R 2 The alkenyl having 2 to 10 carbon atoms is preferably an alkenyl having 2 to 6 carbon atoms, more preferably an alkenyl having 2 to 4 carbon atoms, further preferably vinyl (ethenyl), allyl (2-propenyl), or propenyl (1-propenyl, isoallyl), and particularly preferably vinyl.

[0022] Among the compounds represented by the above formula (1), it is preferable to select the compounds represented by the following formulas (1-1) to (1-9) as component A because they are easy to synthesize and are liquid.

[0023] TIFF2025182682000006.tif213132

[0024] TIFF2025182682000007.tif104127 (In formulas (1-1) to (1-9), m1 is an integer of 1 to 5.)

[0025] Of the compounds represented by the above formulas (1-1) to (1-9), it is preferable to select formula (1-1), formula (1-2), formula (1-3), formula (1-4), or formula (1-7), since a cured product with high heat resistance can be obtained, and it is more preferable to select formula (1-1) or formula (1-7).

[0026] In the compound represented by formula (1) which is component A of the present invention, a compound in which n = 0 can be preferably used because it is easy to synthesize. Specific examples of such suitable compounds include formulas (1-1), (1-2), and (1-3).

[0027] The compound represented by formula (1) above improves the coatability of the composition of the present invention when it is applied to a substrate. In other words, when an optical element is produced using the composition of the present invention, a smooth element without surface irregularities can be obtained. Optical elements with such smooth surfaces exhibit less light scattering and can improve light utilization efficiency. Therefore, the composition of the present invention is particularly suitable for use in optical elements.

[0028] 3. Component B Component B is a compound having two or more thiol groups in the molecule. All applicable compounds, including known compounds, can be used as such compounds. The number of thiol groups (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.

[0029] As such known compounds, it is preferable to select compounds represented by the following formula (2-2) or formula (2-3) because they can impart high transparency and heat resistance to the material.

[0030] TIFF2025182682000008.tif3468 (In formula (2-2), A is alkylene having 1 to 10 carbon atoms, one —CH— in the alkylene may be replaced with —O—, X is SH, OH, or CH, and multiple As or Xs in the formula may be the same or different, provided that at least two of the Xs are SH.)

[0031] TIFF2025182682000009.tif4367 (In formula (2-3), A 2 is alkylene having 1 to 10 carbon atoms, one —CH2— of the alkylene may be replaced by —O— or —S—, X 2 is SH or CH3, and there are multiple A 2 or X 2 may be the same or different, provided that X 2 At least two of them are SH.)

[0032] As the compounds represented by the above formulas (2-2) and (2-3), Multhiol Y-3, Multhiol Y-4 (both trade names, manufactured by SC Organic Chemical Co., Ltd.), or 2,4,6-tris(2-sulfanylethyl)sulfanyl-1,3,5-triazine are more preferably selected because they are easy to synthesize and obtain. Furthermore, Multhiol Y-4 or 2,4,6-tris(2-sulfanylethyl)sulfanyl-1,3,5-triazine are even more preferably selected because they can impart high transparency and heat resistance to the material.

[0033] As a technique disclosed in the present invention, it is most preferable to select a compound represented by the following formula (2-1) as component B, because this improves compatibility with component A and further improves the heat resistance of the cured product. TIFF2025182682000010.tif4669 (In formula (2-1), R 3is -CH2CH2SH or -CH2CH2CH2SH, and R 4 is methyl or phenyl, r is 1 or 2, and there are multiple R 3 or R 4 may be the same or different.)

[0034] Examples of thiol compounds that can be used other than the above-described preferably usable Component B include known compounds such as 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-hexaneedithiol, and 1,10-decanedithiol.

[0035] Of the above known compounds, it is preferable to select 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-hexaneedithiol, or 1,10-decanedithiol because they have excellent heat resistance when cured.

[0036] When selecting a compound represented by the above formula (2-1), formula (2-2), or formula (2-3) as component B, compounds with different structures may be mixed and used. They may also be mixed with the other known thiol compounds described above. In this case, it is preferable to keep the mixing ratio of the other known thiol compounds as low as possible in order to improve transparency and heat resistance.

[0037] 4. Component C The curable composition according to this embodiment preferably contains a polymerization initiator as component C to accelerate curing. Such a polymerization initiator can be selected from known radical polymerization initiators, cationic polymerization initiators, and anionic polymerization initiators. In order 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, and from the viewpoint of accelerating polymerization, it is more preferable to select a radical polymerization initiator.

[0038] Examples of photoradical polymerization initiators that can be suitably used in the curable composition according to this embodiment include alkylphenone-based photopolymerization initiators, acylphosphine oxide-based photopolymerization initiators, and oxime ester-based photopolymerization initiators.

[0039] 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 651, Omnirad 907, Omnirad 369, Omnirad 379, Omnirad 907, and Omnirad 1173 may also be used. Omnirad is a trademark of IGM Resins BV.

[0040] Examples of the acylphosphine oxide photopolymerization initiator 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.

[0041] 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.

[0042] Of these polymerization initiators, it is more preferable to use Omnirad651, Omnirad907, or Omnirad1173 because they have high compatibility with Component A and Component B when no solvent is used in the curable composition of this embodiment. Furthermore, it is even more preferable to use Omnirad651 or Omnirad907 because they have high transmittance in the near-infrared region when the material of the present invention is used for optical waveguide applications.

[0043] The content of the polymerization initiator (C) is preferably 0.5 to 10% by weight, more preferably 1 to 10% by weight, based on the weight of the mixture of components (A) and (B) in order to facilitate photocuring and prevent a decrease in the light resistance and heat resistance of the cured product. However, if there is no concern about the above-mentioned side effects, the polymerization initiator may be added in an amount exceeding the above range.

[0044] A curable material refers to a material in which the 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 obtain 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 the curable material made from the curable composition of the present invention is made into such a thermosetting composition, it can exhibit the excellent properties described above. In the curable composition of the present invention, a photopolymerization initiator, a thermal polymerization initiator, or a combination of these can be selected as the polymerization initiator depending on the desired curing conditions.

[0045] 5. Other Ingredients The curable composition of the present invention comprises essential components A and B, and an optional component C. An optical element obtained by curing such a composition has a high refractive index. Therefore, when the optical element is used in optical waveguide applications, it can be suitably used as a core material that requires a relatively high refractive index. The optical element of the present invention also has high transparency to light from visible light to near-infrared light. Therefore, when the optical element of the present invention is used as a core material for an optical waveguide, optical loss can be reduced.

[0046] In addition to the essential components Components A and B and the optional component Component C, the curable composition of the present invention may contain a compound (D) (hereinafter sometimes referred to as "Component D") other than Component A that has two or more polymerizable double bonds. Component D is not particularly limited as long as it is a compound other than Component A that has two or more polymerizable double bonds per molecule. Component D typically has 2 to 10 polymerizable double bonds, preferably 2 to 6, and more preferably 2 to 4, due to ease of availability.

[0047] Component D may be used alone or as a mixture of two or more kinds in any combination and ratio.

[0048] Any known compound having the above-mentioned characteristics can be used as component D. Examples include 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.

[0049] Specific compounds of component D 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;

[0050] ester compounds having a polymerizable double bond represented by the following: 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;

[0051] 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-methyl (meth)acrylate Examples of the (meth)acrylic compound having a polymerizable double bond include methylpropyl, 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.

[0052] As component D, known silicone compounds that do not contain benzene rings or that contain only a small amount of benzene rings can also be used. The composition of the present invention containing such a compound reduces the refractive index when used in an optical element. Therefore, when the optical element is used in an optical waveguide, it can be suitably used as a cladding material.

[0053] Examples of the silicone compound include 1,3-divinyltetramethyldisiloxane, 2,4,6-trimethyl-2,4,6-trivinylcyclotrisiloxane, 1,3-dimethyl-1,3-diphenyl-1,3-divinyldisiloxane, 2,4,6,8-tetramethyl-2,4,6,8-tetravinylcyclotetrasiloxane, tris[dimethyl(vinyl)siloxy]phenylsilane, tetrakis[dimethyl(vinyl)silyloxy]silane, octavinyloctasilasesquioxane, Silaplane (registered trademark) FM-7711 (trade name; manufactured by JNC Corporation), Silaplane (registered trademark) FM-7721 (trade name; manufactured by JNC Corporation), and compounds represented by the following formula (D1):

[0054] TIFF2025182682000011.tif26125

[0055] Among these silicone compounds, 2,4,6-trimethyl-2,4,6-trivinylcyclotrisiloxane, 1,3-dimethyl-1,3-diphenyl-1,3-divinyldisiloxane, 2,4,6,8-tetramethyl-2,4,6,8-tetravinylcyclotetrasiloxane, tris[dimethyl(vinyl)siloxy]phenylsilane, tetraki ... Preferably, 2,4,6-trimethyl-2,4,6-trivinylcyclotrisiloxane, 1,3-dimethyl-1,3-diphenyl-1,3-divinyldisiloxane, or 2,4,6,8-tetramethyl-2,4,6,8-tetravinylcyclotetrasiloxane is used, and most preferably, 2,4,6-trimethyl-2,4,6-trivinylcyclotrisiloxane is used.

[0056] As component D, double-decker silsesquioxanes having polymerizable double bonds, as described, for example, in WO 2003 / 024870 and WO 2022 / 239271, can also be used.

[0057] Of these specifically exemplified siloxane compounds, in order to improve the transparency and heat resistance of the material, it is preferable to use a double-decker silsesquioxane having a polymerizable double bond, and it is more preferable to use a double-decker silsesquioxane.

[0058] The curable composition according to this embodiment may further contain an organic solvent. The organic solvent is preferably one that can dissolve Component A, Component B, and Component C. Examples of suitable organic solvents include hydrocarbon solvents (e.g., hexane, benzene, toluene, etc.), ether solvents (e.g., diethyl ether, tetrahydrofuran (THF), 2-methyltetrahydrofuran, diphenyl ether, anisole, dimethoxybenzene, cyclopentyl methyl ether (CPME)), halogenated hydrocarbon solvents (e.g., methylene chloride, chloroform, chlorobenzene), ketone solvents (e.g., acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, cyclopentanone), alcohol solvents (e.g., methanol, ethanol, propanol, isopropanol, n-butyl alcohol, tert-butyl alcohol), nitrile solvents (e.g., acetonitrile, propionitrile, benzonitrile), ester solvents (e.g., ethyl acetate, butyl acetate), and carbonate solvents. Examples of suitable organic solvents include carboxylate 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 (HFC) 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). These organic solvents may be used singly or in any combination and ratio of two or more.

[0059] When the curable composition according to the present embodiment contains an organic solvent, the content of the organic solvent 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 properties such as the flatness of the cured film, the content of the organic solvent is preferably 50% by mass to 95% by mass, 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, or when there is a possibility that the amount of solvent remaining in the cured film will increase, the content of the organic solvent is preferably 30% by mass or less, more preferably 20% by mass or less, based on the total amount of the curable composition. Since the curable composition of the present invention can easily maintain a liquid state without using an organic solvent, it is most preferable that the composition does not contain an organic solvent.

[0060] The curable composition according to the present embodiment may contain various additives to improve coating uniformity and adhesion between the cured film and the substrate when the composition is applied to a substrate and cured to form a cured film. Examples of the additives include surfactants (leveling agents), adhesion improvers such as silane coupling agents, antioxidants, ultraviolet absorbers, and anti-aggregation agents.

[0061] 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.

[0062] The surfactants used 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 BYK3 30, 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 TEGO Rad 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).

[0063] When the curable composition according to this embodiment contains a surfactant, the content of the surfactant is preferably 0.01% by mass to 10% by mass relative to the total amount of the curable composition.

[0064] 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.

[0065] 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 in improving adhesion. Examples of commercially available coupling agents include SilaAce S510 (trade name, manufactured by JNC Corporation) and SilaAce S530 (trade name, manufactured by JNC Corporation).

[0066] 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.

[0067] 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 antioxidant may be used alone or in any combination and ratio of two or more kinds.

[0068] 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.

[0069] 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. 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.

[0070] Specific examples of ultraviolet absorbers 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.).

[0071] 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.

[0072] When the curable composition according to the present embodiment contains an organic solvent, it may contain an anti-aggregation agent from the viewpoint of preventing aggregation by making the organic solvent compatible with Component A and Component B, and optionally Component C and other components. The anti-aggregation agent may be used alone, or two or more types may be used in any combination and ratio.

[0073] 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.

[0074] 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.

[0075] 7. Storage of the curable composition The curable composition according to this embodiment is preferably stored in a temperature range of −30° C. to 25° C., since the curable composition has good stability over time. A storage temperature of −20° C. to 10° C. is more preferable, since no precipitates are generated.

[0076] 8. Cured film obtained from the curable composition The curable composition according to this embodiment can be obtained by mixing component A, component B, and, if necessary, component C and other components.

[0077] The curable composition prepared as described above can be used as a varnish for producing a cured film. For example, the varnish is applied to a substrate surface, the resulting coating film is irradiated with light, and then heated as necessary to further promote the curing reaction, thereby forming a cured film of the curable composition.

[0078] Examples of light that can be irradiated onto the varnish include ultraviolet light. UV irradiation onto the varnish can be performed by a conventional method, such as using a high-pressure mercury lamp, an ultraviolet light-emitting diode (LED), or a low-pressure mercury lamp. Since the curable composition of the present invention is not susceptible to oxygen inhibition during curing, photocuring can be performed in the air. However, photocuring is preferably performed in a nitrogen atmosphere to increase the reaction rate.

[0079] The varnish can be applied to the surface of a substrate by a conventionally known method such as drop casting, spin coating, roll coating, dipping, bar coating, slit coating, or application using a dispenser. In this case, to obtain a patterned cured film on a substrate, it is preferable to use a photo-nanoimprinting method to improve productivity. The curable composition of the present invention is highly suitable for producing a cured film by this method because it can reduce the solvent content.

[0080] To improve heat resistance, the coating film obtained by photocuring is preferably heated on a hot plate or in an oven, etc., as necessary, to further promote the curing reaction. The conditions for this heating and baking vary depending on the types and blending ratios of the components, but baking can usually be performed at a temperature of 70°C to 150°C for an appropriate time.

[0081] If necessary, the light irradiation and heating steps can be carried out simultaneously or in the reverse order to form a cured film.

[0082] 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 embodiment of this embodiment, the cured film has high transparency from visible light to the near-infrared region. Furthermore, by changing the selection of components A and 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 can be particularly suitably used as an optical material such as an optical waveguide material or a protective film for a light-emitting element.

[0083] In the curable composition according to this embodiment, there are no particular limitations on the content of Component A. From the viewpoint of photocurability, it is preferable that the number of thiol functional groups in Component B matches the number of double bonds in Component A. Alternatively, from the viewpoint of reducing coloration of the material, the number of double bonds in Component A is preferably 70 to 99.9 mol %, and more preferably 80 to 99.9 mol %, relative to the number of thiol functional groups in Component B.

[0084] The compounds of Component A and Component B of the present invention can be produced according to known methods described in, for example, JP 2016-204425 A and Journal of Polymer Science, PART A: Polymer Chemistry, vol. 54, No. 3, 418 (2016). The synthesis of these compounds will also be described in detail in the following examples. [Example]

[0085] 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.

[0086] The compounds used in the examples and comparative examples will be explained below. <Ingredient A> Formula (1-1-1): The following compound (1-1-1) was synthesized according to Synthesis Example 1 described later. Compound (1-1-1) was a mixture containing compounds with 2 to 4 diphenylsiloxane units, with unit 3 being the main component, and had a weight-average molecular weight of 773. TIFF2025182682000012.tif37109

[0087] <Component B> Formula (2-1-1); In formula (2-1), all R 3 is -CH2CH2SH, and all R 4 A compound where is methyl and r is 2. It was synthesized according to the method described in Journal of Polymer Science, PART A: Polymer Chemistry, vol. 54, No. 3, 418 (2016).

[0088] TIFF2025182682000013.tif4073

[0089] As the compound represented by formula (2-2), Multhiol Y-3 and Multhiol Y-4, which were purchased from SC Organic Chemical Co., Ltd., were used as they were.

[0090] The compound represented by formula (2-3) was 2,4,6-tris(2-sulfanylethyl)sulfanyl-1,3,5-triazine; it was synthesized according to KR20080107548A.

[0091] <Component C> Omnirad1173 (Compound name: 2-hydroxy-2-methylpropiophenone), Omnirad651, Omnirad907 (product names manufactured by IGM Resins B.V.) were purchased as commercial products and used as they were.

[0092] <Component D> 2,4,6-trimethyl-2,4,6-trivinylcyclotrisiloxane (TVC) was purchased as a commercial product and used as it was. Also, as a double-decker type silsesquioxane having a polymerizable double bond, the following compound D2 was used. This compound was synthesized by the method described in International Publication No. 2022 / 239271. TIFF2025182682000014.tif70117

[0093] <NMR Measurement> NMR was measured using an FT-NMR apparatus (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 times. The internal standard was CHCl3 in CDCl3 or tetramethylsilane. Among the NMR notations, s means singlet, d means doublet, t means triplet, m means multiplet, and br means broad. 29 29Si-NMR measurement was similarly carried out using the above FT-NMR apparatus (JNM-ECZ500R).

[0094] <GPC Measurement> The weight average molecular weight (Mw) was analyzed by GPC measurement. An EXTREMA GPC / SEC system (manufactured by JASCO Corporation) was used as the measurement apparatus, and shodex KF-402.5HQ and shodex KF-402HQ (both manufactured by Resonac Co., Ltd.) were connected in series and used as the columns. THF was used as the solvent, and the flow rate was 0.3 ml / min. The measurement was carried out under temperature control at 40°C.

[0095] <PhotoDSC Measurement> To confirm the progress of the curing reaction of the curable composition, PhotoDSC was used. The measuring device used was a photochemical reaction heat calorimeter PDC121 (manufactured by SII NanoTechnology Inc., currently Hitachi High-Tech Corporation). A Xe-Hg lamp was used as the light source, and no interference filter was used. The measurement was carried out at a light intensity of about 70 mW / cm 2 @365 nm. The measurement was carried out under the conditions of a pre-exposure preparation time of 2 minutes, an exposure time of 5 minutes, and a post-exposure stabilization time of 5 minutes for gas replacement in the sample chamber.

[0096] <Curing of the curable composition> It was carried out using a high-pressure mercury lamp (Multi-Lite USH-250BY, manufactured by Ushio Electric Co., Ltd.). No optical filter was used, and curing was carried out at a light intensity of about 70 mW / cm2 @ 365 nm.

[0097] <IR measurement> The measurement was carried out using an infrared absorption spectrometer (Nicolet iS5, manufactured by Thermo Fisher Scientific).

[0098] <Film thickness measurement><0​​​​​​​​​​​​​​​​​​The film was left in an oven at 170°C for one week, and the transparency and hue of the film were confirmed by absorption spectroscopy before and after the evaluation of heat resistance.

[0102] <Glass substrate> An Eagle XG (registered trademark) (manufactured by Corning) measuring 40 mm square and 0.5 mm thick was used.

[0103] [Synthesis Example 1] Synthesis of compound (1-1-1) 4.0 g (18.5 mmol) of commercially available diphenylsilanediol was refluxed in 40 ml of toluene for 4 hours while removing the generated water. After cooling, the solvent was distilled off under reduced pressure. GPC, 1 H-NMR, 29 Si-NMR revealed that the obtained product was a mixture of diphenylsilanediol trimer condensation products, with dimers to tetramers mixed in. This mixture of compounds was used as is in the next reaction.

[0104] The mixture was dissolved in 20 ml of dehydrated THF, and 1.9 ml (14 mmol) of chlorodimethylvinylsilane was added in a nitrogen stream on an ice bath at 10°C or below. Then, 1.1 ml (14 mmol) of dehydrated pyridine was added to the reaction mixture, and the mixture was stirred at room temperature overnight. 70 ml of pure water was added to the reaction mixture, and the mixture was extracted with 70 ml of toluene. The organic layer was washed with 50 ml of saturated sodium bicarbonate water and 50 ml of pure water, and then dried over anhydrous MgSO4. After distilling off the solvent under reduced pressure, the product was purified by column chromatography (silica gel, heptane / toluene = 5 / 1 (volume ratio)). The product was then dried in vacuo to obtain 3.8 g of the target compound (1-1-1) as a mixture.

[0105] 1 H-NMR(ppm,CDCl3);7.65-7.15(m,34H),6.13-5.67(m,6H),0.10-0.03(m,12H).

[0106] (Preparation of Composition) [Example 1] 2.000 g of the compound represented by formula (1-1-1) as component A, 0.6140 g of the compound represented by formula (2-1-1) as component B, and 0.1340 g of Omnirad1173 as component C were weighed out, placed in a sample bottle, and thoroughly mixed with a vortex mixer to prepare composition 1. This composition 1 was homogeneously dissolved in each other and was liquid at room temperature.

[0107] [Example 2] to [Example 11] Compositions 2 to 11 were prepared in the same manner as in Example 1, with the compositions shown in Table 1. Compositions 2 to 11 were liquids at room temperature. The results of Example 1 are also shown below. [Table 1] TIFF2025182682000015.tif192162

[0108] (Tracking of the curing reaction) [Example 12] 15.3 mg of composition 1 was weighed out and subjected to PhotoDSC measurement. As a result, it was confirmed that the reaction was completed with approximately 1 minute of exposure in both nitrogen and air atmospheres. In addition, after the measurement, a small amount of the sample was scraped off and subjected to IR measurement. It was confirmed that the signal of the SH group contained in the compound represented by formula (2-1-1) disappeared in both atmospheres.

[0109] [Example 13] and [Example 14] Curing reaction tracking was carried out for Compositions 2 and 3 in the same manner as in Example 12. The results are shown in Table 2. The results of Example 12 are also shown here. [Table 2] TIFF2025182682000016.tif41144

[0110] (Preparation of cured film and evaluation of transparency) [Example 15] Composition 1 was spin-coated on a glass substrate. The rotation speed of the substrate was 1400 rpm. This sample was exposed to light at an exposure dose of 4.2 J / cm under a nitrogen gas flow. 2The coating was cured by irradiating light at 1000 Hz. The coating thickness of Sample 15 was 14.8 μm. The absorption spectrum of Sample 15 was then measured, and the transmittance was 95% or more in the range of 2500 nm to 380 nm. The refractive index of Sample 15 was 1.55.

[0111] [Example 16] to [Example 28] Cured films were obtained by exposure using Compositions 1 to 11 in the same manner as in Example 15, except that the exposure environment was changed to nitrogen or air, and the transmittance and refractive index were measured. The results are shown in Table 3. The results of Example 15 are also shown here. Table 3 also shows the results of measuring the physical properties of Comparative Examples 1 to 3.

[0112] [Comparative Example 1] Comparative optical materials 1 Composition 20 was prepared according to Example 7 of WO 2015 / 029996. This composition 20 was spin-coated (rotation speed: 1800 rpm) onto a glass substrate. Thereafter, the composition was exposed to light at a dose of 30 J / cm in a nitrogen gas flow. 2 The sample was cured under the conditions. The film thickness of this optical material 1 (sample comparative example 1) was 16.5 μm and the refractive index was 1.59. When the absorption spectrum of sample comparative example 1 was measured, the transmittance was 92% to 93% in the range from 2500 nm to 400 nm. Sample comparative example 1 had an absorption maximum at 2290 nm and a reduced transmittance. The composition of composition 20 is shown below. 15.0 parts by mass: 2,12-diallyl ether dinaphthothiophene 20.0 parts by mass: 1,8-dimercapto-3,6-dioxaoctane (manufactured by Maruzen Petrochemical Co., Ltd., trade name "DMDO") 3.0 parts by mass: bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide (trade name "Omnirad819" manufactured by IGM Resins BV) 65.0 parts by mass: triallyl isocyanurate (trade name "TAIC" manufactured by Mitsubishi Chemical Corporation) 0.002 parts by mass: N-nitrosophenylhydroxylamine aluminum salt (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., trade name "Q-1301")

[0113] Comparative Example 2 Comparative optical materials 2 Composition 21 was prepared according to Example 4 of WO 2016 / 194618. This composition 21 was spin-coated (rotation speed: 4000 rpm) onto a glass substrate. Thereafter, the composition was exposed to light at an exposure dose of 2.2 J / cm in a nitrogen gas flow. 2 The sample was cured under the conditions. The film thickness of this optical material 2 (sample comparative example 2) was 13.6 μm and the refractive index was 1.64. When the absorption spectrum of sample comparative example 2 was measured, the transmittance was 92% to 93% in the range from 2500 nm to 400 nm. Sample comparative example 2 had an absorption maximum at 2306 nm and a reduced transmittance. The composition of composition 21 is shown below. 30 parts by mass: 9,9-bis(4-(2-acryloxyethoxy)phenyl)fluorene 33 parts by mass: 4-mercaptomethyl-1,8-dimercapto-3,6-dithiaoctane 37 parts by mass: 1,4-naphthalenedicarboxylic acid diallyl 0.01 parts by mass: N-nitrosophenylhydroxylamine aluminum

[0114] Comparative Example 3 Comparative optical materials 3 Without using the compound represented by component A, 1.004 g of TVC, 1.2550 g of Multhiol Y-4, and 0.0226 g of Omnirad651 were weighed out, placed in a sample bottle, and thoroughly mixed with a vortex mixer to prepare composition 22. This composition 22 was spin-coated onto a glass substrate (rotation speed: 1000 rpm), and then exposed to an exposure dose of approximately 4 J / cm. 2 The sample was cured under the following conditions: In the case of sample Comparative Example 3, the film had large irregularities and light was scattered, making it impossible to measure the film thickness or transmittance.

[0115] [Table 3] TIFF2025182682000017.tif103160

[0116] [Example 29] Composition 9 was spin-coated on Sample 18 prepared in Example 18 and then photocured in the same manner as in Example 26 to obtain a laminated film. The absorption spectrum of this laminated film (Sample 29) was measured, and the transmittance was 95% or more in the range of 2500 nm to 380 nm.

[0117] (Evaluation of heat resistance) [Example 30] Sample 15 was left in an oven at 170°C for one week, and then its absorption spectrum was measured. As a result, the transmittance at 400 nm had dropped from over 95% before the heat resistance evaluation to 85%, but no coloring or film roughness was visible to the naked eye.

[0118] [Example 31] The heat resistance of Sample 18 was evaluated under the same conditions as in Example 30. As a result, the transmittance at 400 nm was reduced from 95% or more before the heat resistance evaluation to 85%, but no coloring or film roughness was observed visually.

[0119] [Example 32] The heat resistance of Sample 29 was evaluated under the same conditions as in Example 30. As a result, the transmittance at 400 nm was reduced from 95% or more before the heat resistance evaluation to 85%, but no coloring or film roughness was observed visually.

[0120] Comparative Example 4 Sample Comparative Example 1 was left standing in an oven at 170°C for one week, and then its absorption spectrum was measured. As a result, the transmittance at 400 nm had decreased from 92% before the heat resistance evaluation to 67%. Discoloration was clearly visible to the naked eye, indicating damage to the film.

[0121] Comparative Example 5 Sample Comparative Example 2 was left standing in an oven for one week at 170° C. Since film roughness had occurred in this sample, the absorption spectrum was not measured.

[0122] As is clear from the results of the Examples and Comparative Examples, 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 in the near-infrared to visible light range. As such, the composition of the present invention can be suitably used particularly for optical applications. In particular, it is industrially very useful as a material for elements used in high-temperature environments such as automobiles.

[0123] 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]

[0124] 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 the following components A and B: A: A compound having a diphenylsiloxane structure, two or more polymerizable double bonds, and a weight average molecular weight of 5,000 or less. B: A compound having two or more thiol groups.

2. The curable composition according to claim 1 , wherein component A is a compound represented by formula (1): (In formula (1), R １ and R ２ are independently alkenyl having 2 to 10 carbon atoms, methyl, or phenyl; R １ and R ２ at least two of the above are alkenyl having 2 to 10 carbon atoms, m is an integer of 0 to 5, n is 0 or 1, and q is an integer of 1 to 5; multiple m's in the formula may be the same or different; and at least one m is an integer of 1 to 5; and when there are multiple n's in the formula, they may be the same or different.

3. The curable composition according to claim 1, wherein component B is a compound represented by formula (2-1). (In formula (2-1), R ３ is -CH ２ CH ２ SH or -CH ２ CH ２ CH ２ SH and R ４ is methyl or phenyl, r is 1 or 2, and there are multiple R ３ or R ４ may be the same or different.)

4. The curable composition according to claim 1, wherein component B is a compound represented by formula (2-2): (In formula (2-2), A １ is an alkylene having 1 to 10 carbon atoms, and one —CH ２ - may be replaced by -O-, and X １ is SH, OH, or CH ３ and there are multiple A １ or X １ may be the same or different. １ At least two of these are SH.)

5. The curable composition according to claim 1, wherein component B is a compound represented by formula (2-3): (In formula (2-3), A ２ is an alkylene having 1 to 10 carbon atoms, and one —CH ２ - may be replaced by -O- or -S-, and X ２ is SH or CH ３ and there are multiple A ２ or X ２ may be the same or different. ２ At least two of these are SH.)

6. The curable composition of claim 1 further comprising the following component C: C: Polymerization initiator.

7. A cured film obtained by curing the curable composition according to any one of claims 1 to 6.

8. An optical material using the cured film according to claim 7.

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