Curable composition, cured product, and method for producing curable composition

Abstract

The curable composition contains an oligomer complex. The oligomer complex is obtained by coordinating a ligand to a metal alkoxide oligomer, and the number average molecular weight of the metal alkoxide oligomer is 500 or more.

Description

Curable composition, cured product, and method for producing curable composition

[0001] The present invention relates to a curable composition, a cured product, and a method for producing the curable composition.

[0002] There are many optical product technologies that utilize the reflection and refraction of light, and the refractive index greatly affects the properties of refraction. The refractive index is the speed of light in a vacuum divided by the speed of light in a material, and is an index for comparing how light travels through materials. When light travels between materials with different refractive indices, the direction of travel changes at the boundary between them. Refraction refers to this phenomenon, and the law of refraction is also known as Snell's law.

[0003] Known technologies that utilize such refraction include a technology in which a laminated structure that gradually eliminates the difference in refractive index between air and a substrate is used as an anti-reflection coating for a display device such as a monitor, a technology in which a high refractive index material is used to thin optical lenses such as microlens arrays, and a technology in which the light-gathering rate of an optical transceiver or the like is improved (for example, Patent Documents 1 to 3).

[0004] Furthermore, high refractive index materials are expected to be applied to various optical devices such as AR (augmented reality) and VR (virtual reality), and much research and development is being conducted on these materials. Regarding such high refractive index materials, a technique of dispersing metal oxide nanoparticles in a resin is known (for example, Patent Document 4).

[0005] JP 2022-106002 A JP 2008-060121 A JP 2004-096091 A JP 2022-190405 A

[0006] Conventional methods for designing high-refractive-index organic materials typically involve the organic-inorganic hybridization of highly refractive metal nanoparticles into a resin binder. However, mixing nanometals into a resin significantly increases the interfacial energy, making the material thermodynamically unstable and prone to aggregation. This often leads to problems such as opacity and refractive index distribution due to the formation of a heterogeneous system.

[0007] Another method is the sol-gel reaction using metal alkoxides, which increases the refractive index by forming a titanoxane structure through a hydrolysis condensation reaction (sol-gel reaction). However, metal alkoxides are highly reactive, and it has been reported that the rapid progress of the sol-gel reaction can lead to heterogeneity and opacity (Harada Miyuki, Kuratani Hidetoshi, Ochi Koichi, "Network Polymer" Vol. 26 No. 2 (2005) 91-97).

[0008] Another method for suppressing the transparency and refractive index distribution of cured products produced using a sol-gel reaction is the sol-gel reaction using a metal alkoxide monomer complex, in which a ligand is coordinated to a metal alkoxide monomer. Complexation can suppress the sol-gel reaction by reducing the number of sol-gel reaction sites and by steric hindrance of the ligands, and the great advantage of complex formation is that the sol-gel reactivity can be controlled by the equivalent weight of the ligand relative to the central metal element.

[0009] However, as a result of investigations by the inventors, it has been found that when a ligand is introduced under conditions that sufficiently improve the refractive index of a resin binder using a metal alkoxide monomer complex, the sol-gel reactivity becomes too high, and a heterogeneous system is easily formed.

[0010] An object of the present invention is to provide a curable composition that can give a cured product that has a high refractive index, uniformity within the system, and transparency.

[0011] One aspect of the present invention provides a curable composition comprising an oligomer complex, the oligomer complex being a metal alkoxide oligomer to which a ligand is coordinated, and the metal alkoxide oligomer having a number average molecular weight of 500 or more.

[0012] According to the present invention, it is possible to provide a curable composition that can give a cured product that has a high refractive index, uniformity within the system, and transparency.

[0013] Hereinafter, embodiments of the present invention will be described in detail.

[0014] <Curable Composition> The curable composition according to an embodiment of the present invention contains an oligomer complex.

[0015] In this specification, the term "curable composition" refers to a composition that is cured by the application of external energy, such as heat and / or light energy.

[0016] The oligomer complex refers to a complex having a repeating unit structure within the molecule. Here, the complex is a compound in which a ligand is coordinately bonded to a central atom or ion, but it may also be a complex containing two or more central atoms or ions (cluster complex).

[0017] In this embodiment, the oligomer complex is a coordination compound in which a ligand is coordinated to a metal alkoxide oligomer. Here, "coordinating a ligand to a metal alkoxide oligomer" means that the ligand is coordinately bonded to a metal in the metal alkoxide oligomer.

[0018] The metal alkoxide oligomer is represented by, for example, the following formula (1).

[0019]

[0020] The reaction of forming an oligomer complex by coordinating a ligand to a metal alkoxide oligomer is shown, for example, in the following formula (2).

[0021]

[0022] As a result of extensive research, the inventors have found that by using a metal alkoxide oligomer complex in which a ligand is coordinated to a metal alkoxide oligomer, a cured product can be obtained that exhibits high refractive index, uniformity within the system, and transparency due to the reduction in reaction sites caused by the oligomer and the hydrolysis-inhibiting effect of the complex.

[0023] In the above formulas (1) and (2), M is a metal element (central metal). The metal element constituting the metal alkoxide oligomer is not particularly limited, but is, for example, a transition metal, preferably a transition metal of Groups 4, 5, 13, 14, or 15, more preferably titanium (Ti). The metal element may also constitute a metal cluster containing two or more of the same or different metals.

[0024] R is an alkyl group having 1 to 18 carbon atoms, preferably an alkyl group having 3 to 4 carbon atoms. Examples of the alkyl group constituting R include an n-isopropyl group, an n-butyl group, a sec-butyl group, an isobutyl group, and a tert-butyl group. Furthermore, each R may be the same or different. O is oxygen, and OR is an alkoxide. n is an integer of 1 or more. Note that complexes having alkyl groups with too few carbon atoms have high hydrolysis and condensation reactivity, making reaction control difficult. On the other hand, complexes having alkyl groups with too many carbon atoms have low hydrolysis and condensation reactivity, and there is a possibility that a cured product will not be obtained.

[0025] In the formula (2), L represents a ligand. The type of the ligand constituting the metal alkoxide oligomer complex is not particularly limited, and may be either an inorganic mineral or an organic compound, and may be either a monodentate ligand or a polydentate ligand (didentate or higher).

[0026] The ligand may be one type or two or more types. From the viewpoint of stability, a multidentate ligand is preferred, and a bidentate ligand is more preferred. Examples of bidentate ligands include various carboxylic acids, various acrylates, various carboxyacrylates, and various β-diketones.

[0027] The content of the ligand is not particularly limited, but is preferably 0.1 to 3 times by mole, more preferably 0.3 to 2.5 times by mole, and even more preferably 0.5 to 2 times by mole, relative to the metal element in the oligomer complex. If the content of the ligand exceeds 3 times by mole, the refractive index of the entire formulation will decrease. Furthermore, if the content of the ligand is less than 0.1 times by mole, the amount of complex formed with the metal alkoxide oligomer will be small, resulting in a rapid sol-gel reaction and a deterioration in the uniformity of the cured film.

[0028] In this embodiment, the number average molecular weight of the metal alkoxide oligomer is 500 or more. The number average molecular weight of the metal alkoxide oligomer is preferably 500 or more and 10,000 or less, more preferably 500 or more and 3,000 or less, and even more preferably 1,000 or more and 3,000 or less, in order to maintain the liquid viscosity when blended with a complex obtained from the metal alkoxide oligomer and the uniformity within the system during the sol-gel reaction. If the number average molecular weight is less than 500, it becomes difficult to control the sol-gel reaction, and the uniformity of the cured film deteriorates. Examples of methods for calculating the number average molecular weight include gel permeation chromatography (GPC).

[0029] The content of the oligomer complex in the curable composition is not particularly limited, but is preferably 5% by mass or more and 90% by mass or less, more preferably 10% by mass or more and 85% by mass or less, and even more preferably 15% by mass or more and 80% by mass or less. If the content of the oligomer complex exceeds 90% by mass, the film-forming properties will be reduced due to the large amount of alcohol elimination components caused by the sol-gel reaction. If the content of the oligomer complex is less than 5% by mass, the refractive index of the blend will be reduced due to the small effect of the metal alkoxide oligomer.

[0030] The curable composition of the present embodiment may further contain other components in addition to the oligomer complex depending on the purpose, such as a resin (excluding the metal alkoxide oligomer and the oligomer complex), an initiator, an inhibitor, a surfactant, a builder, a pH adjuster, a solvent, an antifoaming agent, a disinfectant, a preservative, a colorant, and a fragrance.

[0031] The resin is not particularly limited, and examples thereof include (meth)acrylic resin, (meth)acrylamide resin, epoxy resin, ene-thiol resin, polycarbonate resin, polyether resin, polyarylate resin, polysulfone resin, polyethersulfone resin, polyphenylene resin, polyarylene ether phosphine oxide resin, polyimide resin, polyamide resin, polyolefin resin, cyclic olefin resin, polyester resin, styrene resin, silicone resin, and urethane resin.

[0032] Polymerizable monomers can be used for such resins. Specific examples of polymerizable monomers include ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, 1,4-butanediol dimethacrylate, neopentyl glycol dimethacrylate, 1,6-hexanediol dimethacrylate, 1,9-nonanediol dimethacrylate, glycerin dimethacrylate, 2-hydroxy-3-acryloyloxypropyl methacrylate, ethylene oxide adduct methacrylate of bisphenol A, and trimethylolpropane trimethacrylate. acrylate, tricyclodecane dimethanol dimethacrylate, glycerin dimethacrylate, trimethylolpropane trimethacrylate, ethoxylated isocyanuric acid triacrylate, ε-caprolactone modified tris-(2-acryloxyethyl)isocyanurate, pentaerythritol triacrylate, ditrimethylolpropane tetraacrylate, ethoxylated pentaerythritol tetraacrylate, pentaerythritol tetraacrylate, dipentaerythritol polyacrylate, dipentaerythritol acrylate, triallyl isocyanurate, triallyl cyanurate, divinylbenzene, divinyl isophthalate, N-phenyl-maleimide, N-phenyl-methylmaleimide, N-phenyl-chloromaleimide, N-p-chlorophenyl-maleimide, N-p-methoxyphenyl-maleimide, N-p-methylphenyl-maleimide, N-p-nitrophenyl-maleimide, N-p-phenoxyphenyl-maleimide, N-p-phenylaminophenyl-maleimide, N-p-phenoxycarbonylphenyl-maleimide, 1 -maleimido-4-acetoxysuccinimide-benzene, 4-maleimido-4'-acetoxysuccinimide-diphenylmethane, 4-maleimido-4'-acetoxysuccinimide-diphenyl ether, 4-maleimido-4'-acetamido-diphenyl ether, 2-maleimido-6-acetamido-pyridine, 4-maleimido-4'-acetamido-diphenylmethane and N-p-phenylcarbonylphenyl-maleimide N-ethylmaleimide, N-2,6-xylylmaleimide, N-cyclohexylmaleimide, N-2,Examples include 3-xylylmaleimide, xylylmaleimide, 2,6-xylenemaleimide, and 4,4'-bismaleimide diphenylmethane.

[0033] These polymerizable monomers may be used alone or in combination of two or more. Among these, (meth)acrylates are preferred from the viewpoint of resin moldability, and polyfunctional (meth)acrylates are more preferred because they provide a cured product with high thermal stability. The term "(meth)acrylate" refers to at least one of acrylate and methacrylate.

[0034] The resin content in the curable composition is not particularly limited, but is preferably 1% by mass or more and 90% by mass or less, more preferably 5% by mass or more and 85% by mass or less, and even more preferably 10% by mass or more and 80% by mass or less. If the resin content in the curable composition is less than 1% by mass, the main polymerization reaction will be the metal alkoxide oligomer, and the film-forming properties will be reduced due to the large amount of alcohol elimination components caused by the sol-gel reaction. On the other hand, if the resin content in the curable composition exceeds 90% by mass, the refractive index of the blend will be reduced because the influence of the metal alkoxide oligomer is small.

[0035] The initiator is a compound (also called a polymerization initiator) added to the curable composition to start a polymerization reaction that synthesizes a polymer from the resin (including the polymerizable monomer) contained in the curable composition. The type of initiator is not particularly limited, and may be either a thermal polymerization initiator or a photopolymerization initiator.

[0036] Examples of the thermal polymerization initiator include peroxides such as benzoyl peroxide, cumene hydroperoxide, 2,5-dimethylhexane-2,5-dihydroperoxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexyne-3, di-t-butyl peroxide, t-butylcumyl peroxide, α,α-bis(t-butylperoxy-m-isopropyl)benzene, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, dicumyl peroxide, di-t-butylperoxyisophthalate, t-butylperoxybenzoate, 2,2-bis(t-butylperoxy)butane, 2,2-bis(t-butylperoxy)octane, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, di(trimethylsilyl)peroxide, and trimethylsilyltriphenylsilyl peroxide. These thermal polymerization initiators may be used alone or in combination of two or more.

[0037] Examples of the photopolymerization initiator include benzophenone, benzil, Michler's ketone, thioxanthone derivatives, benzoin ethyl ether, diethoxyacetophenone, benzil dimethyl ketal, 2-hydroxy-2-methylpropiophenone, 1-hydroxycyclohexyl phenyl ketone, acylphosphine oxide derivatives, 2-methyl-1[4-(methylthio)phenyl]-2-morpholinopropan-1-one, 4-benzoyl-4'-methyldiphenyl sulfide, 2,4,6-trimethylbenzoyl-diphenylphosphine, etc. These photopolymerization initiators may be used alone or in combination of two or more.

[0038] The content of the initiator is not particularly limited, but when the content of the initiator in the curable composition is 0.1% by mass or more and 10% by mass or less, polymerization proceeds sufficiently.

[0039] As described above, the curable composition of this embodiment contains an oligomer complex in which a ligand is coordinated to a metal alkoxide oligomer having a number-average molecular weight of 500 or more, thereby increasing the refractive index of the resulting cured product. Furthermore, when the complexed oligomer is cured to obtain a cured product, the number of sol-gel reaction sites is reduced compared to complex monomers, suppressing aggregation and maintaining uniformity within the system. As a result, the refractive index and transmittance of the resulting cured product can be improved.

[0040] Furthermore, in the curable composition of this embodiment, as described above, when the content of the oligomer complex is 5% by mass or more and 90% by mass or less, the curable composition contains a sufficient amount of the oligomer complex, which has stable sol-gel reactivity and does not produce titanoxane aggregates that cause non-uniformity when the curable composition cures, thereby improving in-system uniformity. As a result, the obtained cured product can have a high transmittance while maintaining a high refractive index.

[0041] Furthermore, in the curable composition of this embodiment, as described above, the content of the ligand is 0.1 to 3 times by mole the metal element in the metal alkoxide oligomer, so that a stable oligomer complex can be formed in the curable composition, thereby improving the in-system uniformity. As a result, the cured product obtained from the curable composition can have a high transmittance while maintaining a high refractive index.

[0042] Furthermore, in the curable composition of the present embodiment, by further containing a resin in addition to the oligomer complex as described above, it is possible to impart the excellent moldability that the resin possesses, and a wide range of applications of resin materials is expected.

[0043] <Cured Product> The cured product according to the embodiment of the present invention is obtained by curing the curable composition according to the embodiment described above. That is, the cured product according to the embodiment is a cured product obtained by curing a curable composition containing an oligomer complex in which a ligand is coordinated to a metal alkoxide oligomer having a number average molecular weight of 500 or more.

[0044] The resulting cured product may be either a product obtained by curing a curable composition that does not contain a resin, or a product obtained by curing a curable composition that contains a resin.

[0045] For example, when a curable composition that does not contain a resin is cured, the oligomer complex alone forms a three-dimensional crosslinked structure, thereby forming a cured film. When a curable composition that contains a resin is cured, an initiator or the like may be optionally added, and the composition may be heated or irradiated with light, as described above, to form a cured product.

[0046] The cured product of the present embodiment is obtained by curing the curable composition of the present embodiment in this manner, and therefore provides the effects of the curable composition of the present embodiment.

[0047] That is, in the cured product of this embodiment, the refractive index of the cured product obtained by the hydrolysis polycondensation reaction of the metal alkoxide is increased by curing a curable composition containing an oligomer complex in which a ligand is coordinated to a metal alkoxide oligomer having a number average molecular weight of 500 or more. Furthermore, when the complexed oligomer is cured to obtain a cured product, the number of sol-gel reaction sites is reduced and aggregation is suppressed, improving uniformity within the system. As a result, the obtained cured product has a high transmittance while maintaining its refractive index.

[0048] <Method for producing curable composition> A method for producing a curable composition according to an embodiment of the present invention includes a step of mixing a metal alkoxide oligomer having a number average molecular weight of 500 or more with a ligand to prepare a curable composition containing an oligomer complex. The oligomer complex contained in the curable composition is a metal alkoxide oligomer to which a ligand is coordinated. The method for producing a curable composition according to this embodiment can obtain the curable composition of this embodiment described above.

[0049] In the method for producing the curable composition, as shown in the above formula (2), a reaction proceeds in which a ligand is coordinated to a metal alkoxide oligomer to form an oligomer complex. The reaction conditions for forming the oligomer complex are arbitrary. For example, a metal alkoxide oligomer such as titanium butoxide oligomer and a ligand such as acetylacetone are placed in a container under inert conditions and stirred.

[0050] The molar ratio of the metal alkoxide oligomer to the ligand is optional, but is, for example, 1:9 to 9:1, preferably 1:4 to 4:1, and more preferably 2:3 to 3:2.

[0051] The temperature during stirring is arbitrary but is, for example, 5 to 50° C., preferably 10 to 40° C., and more preferably 20 to 30° C. The stirring time is arbitrary but is, for example, 1 to 36 hours, preferably 3 to 24 hours, and more preferably 6 to 12 hours.

[0052] In the method for producing a curable composition according to this embodiment, the curable composition according to this embodiment can be obtained as described above, and the obtained curable composition can provide the effects of the curable composition according to this embodiment.

[0053] That is, the method for producing a curable composition according to this embodiment produces a curable composition containing an oligomer complex in which a ligand is coordinated to a metal alkoxide oligomer having a number-average molecular weight of 500 or more, thereby increasing the refractive index of the resulting cured product. Furthermore, the curable composition contains a sufficient amount of oligomer complex with stable sol-gel reactivity that does not produce titanoxane aggregates, which can cause non-uniformity, when the complexed oligomer is cured, improving uniformity within the system. As a result, the resulting cured product exhibits high transmittance while maintaining its refractive index.

[0054] Hereinafter, this embodiment will be further described using experimental examples. Various tests and evaluations were performed according to the following methods. In the following, "parts" and "%" are by mass unless otherwise specified.

[0055] <Synthesis of Oligomer Complex> [Synthesis Example 1] 6.5 g (11.8 mmol) (calculated as titanium tetrabutoxide monomer) of Ti butoxide oligomer (PC-200, manufactured by Matsumoto Fine Chemical Co., Ltd.) as a metal alkoxide oligomer and 0.6 g (11.8 mmol) of acetylacetone (manufactured by Tokyo Chemical Industry Co., Ltd.) as a ligand were added to a vial under inert conditions and stirred overnight at room temperature to obtain Compound 1 (oligomer complex). Note that PC-200 had a number average molecular weight (Mn) of 1,753 as a result of measurement by gel permeation chromatography (GPC).

[0056] The compound 1 was analyzed by Fourier transform infrared spectroscopy (FT-IR) (Nicolet® iS10, manufactured by Thermo Fisher Scientific) to identify the carbonyl stretching vibration of the ketone group at 1710 cm before coordination. －１ The peak around 1520 cm due to the C—O stretching vibration after coordination disappears. －１ The observation of new peaks confirmed the successful synthesis.

[0057] Synthesis Example 2 6.5 g (11.8 mmol) (calculated as titanium tetrabutoxide monomer) of Ti butoxide oligomer (PC-200, manufactured by Matsumoto Fine Chemical Co., Ltd.) as a metal alkoxide oligomer and 2.7 g (11.8 mmol) of 2-methacryloyloxyethyl succinic acid (A-SA, manufactured by Shin-Nakamura Chemical Co., Ltd.) as a ligand were added to a vial under inert conditions and stirred overnight at room temperature to obtain Synthesis Product 2 (oligomer complex).

[0058] Using FT-IR (Nicolet iS10, manufactured by Thermo Fisher Scientific), the carbonyl stretching vibration of the carboxyl group at 1710 cm was observed for Synthetic Product 2 before coordination. －１ The peak around 1550 cm due to the C—O stretching vibration after coordination disappears. －１ The observation of new peaks confirmed the successful synthesis.

[0059] Synthesis Example 3 4.0 g (11.8 mmol) of Ti tetrabutoxide monomer (molecular weight: 340.32) (manufactured by Tokyo Chemical Industry Co., Ltd.), which is a metal alkoxide monomer, and 1.2 g (11.8 mmol) of acetylacetone (manufactured by Tokyo Chemical Industry Co., Ltd.) as a ligand were added to a vial under inert conditions and stirred overnight at room temperature to obtain Synthesis Product 3 (oligomer complex).

[0060] Using FT-IR (Nicolet iS10, manufactured by Thermo Fisher Scientific), the compound 3 was observed to have a 1710 cm band derived from the carbonyl stretching vibration of the ketone group before coordination. －１ The peak around 1520 cm due to the C—O stretching vibration after coordination disappears. －１The observation of new peaks confirmed the successful synthesis.

[0061] <Preparation of Curable Composition and Cured Product> [Example 1] A solution (curable composition) was prepared by blending 80 parts of Synthetic Product 1 as an oligomer complex, 20 parts of tricyclodecane dimethanol dimethacrylate (DCP-M, manufactured by Shin-Nakamura Chemical Co., Ltd.) as a resin, 0.03 parts of 2-hydroxy-2-methylpropiophenone (Omnirad (registered trademark) 1173, manufactured by IGM Resins B.V.) as an initiator, and 0.03 parts of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (Omnirad (registered trademark) TPO-H, manufactured by IGM Resins B.V.). The formulation for Example 1 is shown in Table 1.

[0062] The prepared solution was used in a UV irradiation device (I-Grandage ECS-401GX, manufactured by I-Graphics Co., Ltd.) equipped with a high-pressure mercury lamp (H04-L41, manufactured by I-Graphics Co., Ltd.) at an illuminance of 2 J / cm ２ After irradiation, the film was heated at 120°C for 60 minutes in a thermo-hygrostat (STPH-101, manufactured by Espec Corp.) to produce a cured film (cured product). The resulting cured film was formed on a slide glass (S9111, manufactured by Matsunami Glass Industrial Co., Ltd.) to a thickness of 4 µm and evaluated.

[0063] [Transmittance and Haze Value] Measurements were made using a haze meter (NDH 7000SP, manufactured by Nippon Denshoku Industries Co., Ltd.). A transmittance of 90% or more and a haze value of 1% or less was evaluated as good. As a result of the measurement, the total light transmittance was 90% or more and the haze value was 1% or less, and the transparency was evaluated as sufficient (good). The results are shown in Table 1.

[0064] [Refractive Index] The refractive index was measured using a refractometer (Prism Coupler 2010 / M, manufactured by Metricon Japan). If the refractive index was higher than that of Comparative Example 3 (an example containing DCP-M alone as the resin), it was evaluated as good. As a result of the measurement, the refractive index was higher than that of the resin alone (good). The results are shown in Table 1.

[0065] [In-system uniformity] Secondary electron images were taken at 50,000 magnifications and observed using an FE-SEM (Helios5 UC Dual Beam, manufactured by Thermo Fisher Scientific). The in-system uniformity was evaluated as good when it was confirmed that no aggregates were present. As a result of the observation, no aggregates were confirmed (good). The results are shown in Table 1.

[0066] A solution (curable composition) and a cured film (cured product) were prepared in the same manner as in Example 1, except that 50 parts of Synthetic Product 1 was used as the oligomer complex and 50 parts of tricyclodecane dimethanol dimethacrylate (DCP-M, manufactured by Shin-Nakamura Chemical Co., Ltd.) was used as the resin. The formulation for Example 2 is shown in Table 1.

[0067] As in Example 1, Example 2 was measured using a haze meter, and the total light transmittance was 90% or more and the haze value was 1% or less, indicating sufficient transparency (transmittance and haze value: good). Furthermore, the refractive index was measured using a refractometer, and found to be higher than the refractive index of the resin alone (refractive index: good). Furthermore, secondary electron images were taken at 50,000x magnification using an FE-SEM, and no aggregates were observed (uniformity within the system: good).

[0068] Example 3 A solution (curable composition) and a cured film (cured product) were prepared in the same manner as in Example 1, except that 20 parts of Synthetic Product 1 was used as the oligomer complex and 80 parts of tricyclodecane dimethanol dimethacrylate (DCP-M, manufactured by Shin-Nakamura Chemical Co., Ltd.) was used as the resin. The formulation for Example 3 is shown in Table 1.

[0069] As in Example 1, Example 3 was measured using a haze meter, and the total light transmittance was 90% or more and the haze value was 1% or less, indicating sufficient transparency (transmittance and haze value: good). Furthermore, the refractive index was measured using a refractometer, and found to be higher than the refractive index of the resin alone (refractive index: good). Furthermore, secondary electron images were taken at 50,000x magnification using an FE-SEM, and no aggregates were observed (uniformity within the system: good).

[0070] Example 4 A solution (curable composition) and a cured film (cured product) were prepared in the same manner as in Example 1, except that Synthetic Product 1 was replaced with Synthetic Product 2 as the oligomer complex. The formulation of Example 4 is shown in Table 1.

[0071] As in Example 1, Example 4 was measured using a haze meter, and the total light transmittance was 90% or more and the haze value was 1% or less, indicating sufficient transparency (transmittance and haze value: good). Furthermore, the refractive index was measured using a refractometer, and found to be higher than the refractive index of the resin alone (refractive index: good). Furthermore, secondary electron images were taken at 50,000x magnification using an FE-SEM, and no aggregates were observed (uniformity within the system: good).

[0072] Comparative Example 1 A solution (curable composition) and a cured film (cured product) were prepared in the same manner as in Example 1, except that the oligomer complex was replaced with Synthetic Product 3 instead of Synthetic Product 1. The formulation of Comparative Example 1 is shown in Table 1.

[0073] For Comparative Example 1, as in Example 1, measurements were performed using a haze meter. The total light transmittance was 90% or less and the haze value was 1% or less, and the transparency was evaluated as insufficient (transmittance and haze value: poor). Furthermore, measurements of the refractive index using a refractometer showed that the refractive index was higher than that of the resin alone (refractive index: good). Furthermore, secondary electron images were taken at 50,000 magnification using an FE-SEM, and aggregates were confirmed (in-system uniformity: poor).

[0074] Comparative Example 2 A solution was prepared by blending 100 parts of Ti butoxide oligomer (PC-200, Mn: 1753, manufactured by Matsumoto Fine Chemical Co., Ltd.) as a metal alkoxide oligomer, 0.03 parts of 2-hydroxy-2-methylpropiophenone (Omnirad (registered trademark) 1173, manufactured by IGM Resins B.V.) as an initiator, and 0.03 parts of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (Omnirad (registered trademark) TPO H, manufactured by IGM Resins B.V.) as an initiator, and a cured film was prepared in the same manner as in Example 1. The formulation of Comparative Example 2 is shown in Table 1.

[0075] For Comparative Example 2, as in Example 1, measurements were performed using a haze meter, resulting in a total light transmittance of 90% or less and a haze value of 1% or more, and the transparency was evaluated as insufficient (transmittance and haze value: poor). Furthermore, measurements of the refractive index using a refractometer resulted in no combined value being obtained (refractive index: poor). Furthermore, secondary electron images were taken at 50,000 magnification using an FE-SEM, and aggregates were confirmed (in-system uniformity: poor).

[0076] A solution (curable composition) and a cured film (cured product) were prepared in the same manner as in Comparative Example 2, except that tricyclodecane dimethanol dimethacrylate (DCP-M, manufactured by Shin-Nakamura Chemical Co., Ltd.) was used as a resin instead of the metal alkoxide oligomer. The formulation of Comparative Example 3 is shown in Table 1.

[0077] For Comparative Example 3, similar to Example 1, measurements were performed using a haze meter, and the total light transmittance was 90% or more and the haze value was 1% or less, indicating sufficient transparency (transmittance and haze value: good). The refractive index was also measured using a refractometer to confirm the refractive index of the resin alone (reference refractive index). Furthermore, secondary electron images were taken at 50,000x magnification using an FE-SEM, and no aggregates were observed (uniformity within the system: good).

[0078] Comparative Example 4 A solution was prepared by blending 66.7 parts of Ti butoxide oligomer (Mn: 1753) (PC-200, manufactured by Matsumoto Fine Chemical Co., Ltd.) as a metal alkoxide oligomer, 33.3 parts of tricyclodecane dimethanol dimethacrylate (DCP-M, manufactured by Shin-Nakamura Chemical Co., Ltd.) as a resin, 0.03 parts of 2-hydroxy-2-methylpropiophenone (Omnirad (registered trademark) 1173, manufactured by IGM Resins B.V.) as an initiator, and 0.03 parts of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (Omnirad (registered trademark) TPO H, manufactured by IGM Resins B.V.), and a cured film was prepared in the same manner as in Example 1. The formulation of Comparative Example 4 is shown in Table 1.

[0079] For Comparative Example 4, similar to Example 1, measurements were performed using a haze meter. The total light transmittance was 90% or less and the haze value was 1% or more, and the transparency was evaluated as insufficient (transmittance and haze value: poor). Furthermore, the refractive index was measured using a refractometer, and it was found to be higher than the refractive index of the resin alone (refractive index: good). Furthermore, secondary electron images were taken at 50,000 times magnification using an FE-SEM, and aggregates were confirmed (in-system uniformity: poor). The results are shown in Table 1.

[0080] As can be seen from Table 1, the curable compositions containing oligomer complexes in which a ligand is coordinated to a metal alkoxide oligomer having a number-average molecular weight of 500 or more provided cured products with good transmittance, haze value, refractive index, transparency, and in-system uniformity (Examples 1 to 4).

[0081] In contrast, when the conditions for a curable composition containing an oligomer complex in which a ligand is coordinated to a metal alkoxide oligomer having a number average molecular weight of 500 or more were not satisfied, at least one of the transmittance, haze value, refractive index, transparency, and in-system uniformity was poor (Comparative Examples 1 to 4).

[0082] Preferred embodiments of the present invention will be described below.

[0083] (Appendix 1) A curable composition comprising an oligomer complex, wherein the oligomer complex is a metal alkoxide oligomer to which a ligand is coordinated, and the metal alkoxide oligomer has a number average molecular weight of 500 or more.

[0084] (Appendix 2) The curable composition according to Appendix 1, wherein the content of the oligomer complex is 5% by mass or more and 90% by mass or less.

[0085] (Appendix 3) The curable composition according to appendix 1 or 2, wherein the content of the ligand is 0.1 to 3 times by mole the metal element in the metal alkoxide oligomer.

[0086] (Appendix 4) The curable composition according to any one of Appendices 1 to 3, further comprising a resin.

[0087] (Appendix 5) A cured product obtained by curing the curable composition according to any one of Appendices 1 to 4.

[0088] (Appendix 6) A method for producing a curable composition, comprising the step of mixing a metal alkoxide oligomer having a number average molecular weight of 500 or more with a ligand to prepare a curable composition containing an oligomer complex in which the ligand is coordinated to the metal alkoxide oligomer.

[0089] Although the embodiments of the present invention have been described above, the present invention is not limited to the specific embodiments, and various modifications and changes are possible within the scope of the invention described in the claims.

[0090] This application claims priority based on Japanese Patent Application No. 2023-207878, filed December 8, 2023, the entire contents of which are incorporated herein by reference.

Claims

1. A curable composition comprising an oligomer complex, the oligomer complex being a metal alkoxide oligomer to which a ligand is coordinated, the metal alkoxide oligomer having a number average molecular weight of 500 or more.

2. The curable composition according to claim 1, wherein the content of the oligomer complex is 5% by mass or more and 90% by mass or less.

3. The curable composition according to claim 1, wherein the content of the ligand is 0.1 to 3 times by mol relative to the metal element in the metal alkoxide oligomer.

4. The curable composition according to claim 1, further comprising a resin.

5. A cured product obtained by curing the curable composition according to any one of claims 1 to 4.

6. A method for producing a curable composition, comprising the step of mixing a metal alkoxide oligomer having a number average molecular weight of 500 or more with a ligand to prepare a curable composition containing an oligomer complex in which the ligand is coordinated to the metal alkoxide oligomer.

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