Curable resin composition

Abstract

To provide a highly reliable curable resin composition containing quantum dots in which the quantum dots can be dispersed in a curable resin at a high concentration without aggregation.SOLUTION: The present invention provides a curable resin composition containing quantum dots, wherein the curable resin composition is a mixture of a thermosetting resin and a silsesquioxane polymer in which the quantum dots are copolymerized with silsesquioxane.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a curable resin composition containing quantum dots. [Background technology]

[0002] Semiconductor crystal particles with nano-sized particle diameters are called quantum dots, and the energy levels of the semiconductor crystal particles become discrete because the excitons generated by light absorption are confined in nano-sized regions, and the band gap changes depending on the particle diameter. Due to these effects, the fluorescent emission of quantum dots is brighter, more efficient, and sharper than that of general phosphors. In addition, because the band gap changes depending on the particle size, the emission wavelength can be controlled, and quantum dots are expected to be used as wavelength conversion materials in solid-state lighting and displays. For example, using quantum dots as wavelength conversion materials in displays can achieve a wider color gamut and lower power consumption than conventional phosphor materials.

[0003] As a mounting method for using quantum dots as a wavelength conversion material, a method has been proposed in which quantum dots are dispersed in a resin material, and the resin material containing the quantum dots is laminated with a transparent film to incorporate it into a backlight unit as a wavelength conversion film (Patent Document 1). It has also been proposed that quantum dots can be used as a color filter material, allowing the quantum dots to absorb monochromatic blue light from a backlight unit and emit red or green light, thereby functioning as a color filter and wavelength conversion material, thereby making it suitable for use in image elements with high efficiency and excellent color reproducibility (Patent Document 2). Micro LED displays, in which the backlight unit is replaced with a micro-sized LED array, are attracting attention. In micro LED displays, it is required to form a color filter on a micro-sized LED. A lithography process using a curable material has been proposed as a method for forming a quantum dot color filter on an LED array (Patent Document 3). In recent years, the size of this LED array has been miniaturized, and finer patterning of quantum dots than ever before is required. In addition, in color filter applications, it is also necessary to increase the light absorption of the color filter in order to suppress leakage of blue monochromatic light, which is the excitation light, from the color filter. In order to increase the light absorption of the color filter, it is necessary to increase the quantum dot concentration. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Special Publication No. 2013-544018 [Patent Document 2] JP 2017-021322 A [Patent Document 3] Patent Publication No. 2021-089347 [Patent Document 4] Special Publication No. 2016-518468 [Patent Document 5] Special Publication No. 2013-505346 [Patent Document 6] Patent No. 6283092 [Non-patent literature]

[0005] [Non-Patent Document 1] Journal of Photopolymer Science and Technology, Vol 23, 2010, p115-119 Summary of the Invention [Problem to be solved by the invention]

[0006] Generally, curable resin materials such as acrylic resins and silicone resins have polarity and are dispersed in polar solvents such as PGMEA and PGME. Therefore, the compatibility with quantum dots, which are basically hydrophobic, is poor, and aggregation occurs, which is a major problem. In particular, the problem of aggregation becomes more serious when the concentration of quantum dots is increased. The aggregates of quantum dots inhibit the crosslinking of the resin during curing, reducing the curability, and the presence of aggregates inside the wavelength conversion material obtained by curing this resin composition causes uneven emission intensity, which has a negative effect on the product characteristics. The addition of a dispersant has been considered as a countermeasure against the aggregation of quantum dots, but there are problems such as reducing the quantum dot content, inhibiting curing and causing coloring during the curing process of the curable resin, and altering the properties of the resin after curing.

[0007] In addition, since the quantum dots in the cured resin composition are present in the resin material, unlike the environment in a solution, the ligands are more likely to be removed, and deterioration of the luminescence characteristics over time is also a problem.

[0008] In response to these problems, various methods have been proposed to improve the dispersibility of quantum dots in polar solvents or resin materials or to improve stability, such as surface coating (Patent Document 4) or encapsulation (Patent Document 5), and binding of polyhedral oligomeric silsesquioxane ligands (Patent Document 6). However, it is difficult to simultaneously achieve dispersibility in resin materials, inhibition of aggregation and stability at high concentrations, particularly when the quantum dot content is 10 parts by mass or more, as well as the curability of the composition when mixed with a resin.

[0009] The present invention has been made in consideration of the above-mentioned problems, and has an object to provide a curable resin composition containing highly reliable quantum dots, which can disperse quantum dots in a curable resin at a high concentration without agglomeration. [Means for solving the problem]

[0010] In order to solve the above problems, the present invention provides a curable resin composition containing quantum dots, the curable resin composition being a mixture of a silsesquioxane polymer in which the quantum dots are copolymerized with silsesquioxane, and a thermosetting resin.

[0011] In such a curable resin composition, the quantum dots can be dispersed in the curable resin at a high concentration without aggregation, resulting in a curable resin composition containing highly reliable quantum dots.

[0012] The present invention also provides a curable resin composition containing quantum dots, the curable resin composition being a mixture of a silsesquioxane polymer in which the quantum dots and an alkoxysilane are copolymerized, and a thermosetting resin.

[0013] Even in such a curable resin composition, the quantum dots can be dispersed in the curable resin at a high concentration without aggregation, resulting in a curable resin composition containing highly reliable quantum dots.

[0014] In the present invention, it is preferable that the surface of the quantum dots is modified with a silane coupling agent.

[0015] Such quantum dots are preferable because they are easily copolymerized with silsesquioxane or alkoxysilane.

[0016] In the present invention, the alkoxysilane preferably comprises two or more types of alkoxysilanes each having a different functional group.

[0017] If such an alkoxysilane is used, the degree of crosslinking of the silsesquioxane obtained by copolymerization can be controlled, and this makes it possible to control the viscosity of the resulting curable resin composition, making it possible to adjust the viscosity in accordance with the production process.

[0018] In the present invention, the alkoxysilane preferably comprises at least one kind of alkoxysilane selected from the group consisting of monoalkoxysilane, dialkoxysilane, and trialkoxysilane.

[0019] Even with such alkoxysilanes, the degree of crosslinking of the silsesquioxane obtained by copolymerization can be controlled, and this makes it possible to control the viscosity of the resulting curable resin composition, making it possible to adjust the viscosity in accordance with the production process.

[0020] In the present invention, the silane coupling agent preferably has at least one of an amino group, a thiol group, a carboxy group, a phosphino group, a phosphine oxide group, and an ammonium ion.

[0021] Such a silane coupling agent is preferable because it has high coordination with the quantum dots and improves the affinity of the quantum dots to the silsesquioxane. It is also preferable because the polarity of the quantum dots and the silsesquioxane can be controlled, and the dispersibility with the curable resin can be improved by adjusting the polarity of the curable resin.

[0022] In the present invention, the silsesquioxane preferably has, as a functional group, one or more reactive substituents selected from the group consisting of a vinyl group, an acrylic group, a methacrylic group, a hydroxyl group, a phenolic hydroxyl group, an epoxy group, and a glycidyl group.

[0023] Such a functional group is preferable from the viewpoint of improving the patterning property of the curable resin composition.

[0024] In the present invention, the alkoxysilane preferably has, as a functional group, one or more reactive substituents selected from the group consisting of a vinyl group, an acrylic group, a methacrylic group, a hydroxyl group, a phenolic hydroxyl group, an epoxy group, and a glycidyl group.

[0025] Such a functional group is preferable from the viewpoint of improving the patterning property of the curable resin composition.

[0026] In the present invention, the thermosetting resin is preferably an acrylic resin having a (meth)acryloyl group in a side chain.

[0027] Such a thermosetting resin can be suitably used in the curable resin composition of the present invention.

[0028] In the present invention, the thermosetting resin is preferably an acid crosslinkable group-containing silicone resin.

[0029] Such a thermosetting resin can be suitably used in the curable resin composition of the present invention. Effect of the Invention

[0030] As described above, with the curable resin composition of the present invention, quantum dots can be dispersed in a curable resin at a high concentration without aggregation, and a curable resin composition containing highly reliable quantum dots can be obtained. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0031] As described above, there has been a demand for the development of a highly reliable curable resin composition containing quantum dots, which can disperse quantum dots in a curable resin at a high concentration without agglomeration.

[0032] Means for Solving the Problems The present inventors have conducted extensive research into the above-mentioned problems and have come up with the idea of ​​mixing a silsesquioxane polymer obtained by copolymerizing quantum dots and silsesquioxane with a thermosetting resin, thereby completing the present invention.

[0033] That is, the present invention relates to a curable resin composition containing quantum dots, the curable resin composition being a mixture of a silsesquioxane polymer in which the quantum dots are copolymerized with silsesquioxane, and a thermosetting resin.

[0034] The present invention also relates to a curable resin composition containing quantum dots, the curable resin composition being a mixture of a silsesquioxane polymer in which the quantum dots and an alkoxysilane are copolymerized, and a thermosetting resin.

[0035] The present invention will be described in detail below, but the present invention is not limited thereto.

[0036] In the present invention, the silsesquioxane polymer in which quantum dots are copolymerized with silsesquioxane, or the silsesquioxane polymer in which quantum dots are copolymerized with alkoxysilane, is not a copolymer of quantum dots directly with silsesquioxane or alkoxysilane, but a copolymer of ligands modified on the quantum dot surface with silsesquioxane or alkoxysilane, i.e., a copolymer of quantum dots having ligands on their surface with silsesquioxane or alkoxysilane.

[0037] In the present invention, the composition and manufacturing method of the quantum dots are not particularly limited, and quantum dots can be selected according to the purpose. Examples of the composition of the quantum dots include II-IV group semiconductors, III-V group semiconductors, II-VI group semiconductors, I-III-VI group semiconductors, II-IV-V group semiconductors, IV group semiconductors, perovskite type semiconductors, etc. Furthermore, the quantum dots may have only a core or a core-shell structure, and the particle size can be appropriately selected according to the desired wavelength range.

[0038] Specific examples of core materials include CdSe, CdS, CdTe, InP, InAs, InSb, AlP, AlAs, AlSb, ZnSe, ZnS, ZnTe, Zn3P2, GaP, GaAs, GaSb, CuInSe2, CuInS2, CuInTe2, CuGaSe2, CuGaS2, CuGaTe2, CuAlSe2, CuAlS2, CuAlTe2, AgInSe2, AgInS2, AgInTe, AgGaSe2, AgGaS2, AgGaTe2, PbSe, PbS, PbTe, Si, Ge, graphene, CsPbCl3, CsPbBr3, CsPbI3, CH3NH3PbCl3, and mixed crystals and those with dopants added.

[0039] Examples of shell materials include ZnO, ZnS, ZnSe, ZnTe, CdS, CdSe, CdTe, AlN, AlP, AlAs, AlSb, GaN, GaP, GaAs, GaSb, InN, InP, InAs, AlSb, BeS, BeSe, BeTe, MgS, MgSe, MgTe, PbS, PbSe, PbTe, SnS, SnSe, SnTe, CuF, CuCl, CuBr, CuI, and mixed crystals of these.

[0040] Furthermore, the quantum dots may be spherical, cubic, or rod-shaped, and the shape of the quantum dots is not limited and can be freely selected. The average particle size of quantum dots is desirably 20 nm or less. If the average particle size is 20 nm or less, the quantum size effect can be obtained, the luminous efficiency does not decrease, and the band gap can be controlled by the particle size.

[0041] The particle size of the quantum dots can be calculated from the average of the maximum diameters in a specific direction, i.e., the Feret diameters, of 20 or more particles measured by a particle image obtained by a transmission electron microscope (TEM). Of course, the method for measuring the average particle size is not limited to this, and other methods can also be used.

[0042] The surface of the quantum dot may have a ligand, and the ligand preferably contains an aliphatic hydrocarbon from the viewpoint of dispersibility. Examples of such ligands include oleic acid, stearic acid, palmitic acid, myristic acid, lauric acid, decanoic acid, octanoic acid, oleylamine, stearyl (octadecyl)amine, dodecyl (lauryl)amine, decylamine, octylamine, octadecanethiol, hexadecanethiol, tetradecanethiol, dodecanethiol, decanethiol, octanethiol, trioctylphosphine, trioctylphosphine oxide, triphenylphosphine, triphenylphosphine oxide, tributylphosphine, and tributylphosphine oxide, and the like, and these may be used alone or in combination.

[0043] The quantum dot surface can be surface-modified with a silane coupling agent. The silane coupling agent preferably has an amino group, a thiol group, a carboxy group, a phosphino group, a phosphine oxide group, or an ammonium ion. Examples of the silane coupling agent include 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, aminophenyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropyltriethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyl(dimethoxy)methylsilane, triethoxysilylpropylmaleamic acid, [(3-triethoxysilyl)propyl]succinic anhydride, X-12-1135 (manufactured by Shin-Etsu Chemical Co., Ltd.), diethylphosphatoethyltriethoxysilane, 3-trihydroxypropylmethylphosphonate sodium salt, and trimethyl[3-(trimethoxysilyl)propyl]ammonium chloride.

[0044] In one embodiment, the quantum dots surface-modified with a silane coupling agent can be copolymerized with silsesquioxane. The copolymerization method is not particularly limited. For example, the surface-modified quantum dots and silsesquioxane can be mixed in a mixed solvent of toluene and ethanol, and a small amount of water and a catalyst can be added to react with each other to copolymerize the quantum dots and silsesquioxane. There is no particular limit to the type of catalyst, and an acid or an alkali can be used. Examples of catalysts include formic acid, hydrochloric acid, nitric acid, acetic acid, aqueous ammonia, and tetramethylammonium hydroxide.

[0045] The structure of the silsesquioxane is not particularly limited, and may be a cage structure, a ladder structure, a random structure, or the like, and may be appropriately selected according to the purpose. From the viewpoint of dispersibility and uniformity in the curable resin, a random structure is preferred. The functional group contained in the silsesquioxane is not limited, and may be appropriately substituted according to the purpose. As the substituent, a substituent capable of crosslinking with the curable resin is particularly preferred from the viewpoint of improving the patterning property of the curable resin composition. Examples of the functional group of the silsesquioxane include a vinyl group, an allyl group, a glycidyl group, a hydroxyl group (hydroxyl group), a phenol group, an acrylic group, a methacrylic group, a thiol group, a phenolic hydroxyl group, and an epoxy group.

[0046] In one embodiment, the quantum dots surface-modified with a silane coupling agent and an alkoxysilane can be copolymerized to produce a silsesquioxane polymer. The copolymerization method is not particularly limited. Methods such as Non-Patent Document 1 are known as methods for synthesizing silsesquioxane. For example, a silsesquioxane polymer can be obtained by mixing the surface-modified quantum dots and an alkoxysilane in a mixed solvent of toluene and ethanol, and adding a small amount of water and a catalyst to cause a reaction. There are no particular limitations on the type or amount of catalyst added, and an acid or alkali can be used. Examples of catalysts include formic acid, hydrochloric acid, nitric acid, acetic acid, aqueous ammonia, and tetramethylammonium hydroxide.

[0047] The silane coupling agent is not particularly limited and can be appropriately selected according to the desired resin properties. As the silane coupling agent, those having an amino group, a carboxy group, a phosphino group, a phosphine oxide group, an ammonium ion, a vinyl group, an allyl group, a glycidyl group, a phenyl group, an acryl group, a methacryl group, or a thiol group as a functional group are preferable. In addition, a silane coupling agent having not only one type of functional group but also two or more types of functional groups may be used. Examples of silane coupling agents include trimethoxyvinylsilane, triethoxyvinylsilane, trimethoxy(4-vinylphenyl)silane, allyltriethoxysilane, allyltrimethoxysilane, triethoxy(3-glycidyloxypropyl)silane, 3-glycidyloxypropyltrimethoxysilane, [8-(glycidyloxy)-n-octyl]trimethoxysilane, KBM-573 (manufactured by Shin-Etsu Chemical Co., Ltd.), (3-methacryloyloxypropyl)triethoxysilane, (3-methacryloyloxypropyl)trimethoxysilane, 3-(trimethoxysilyl)propyl acrylate, 3-mercaptopropyltriethoxysilane, and 3-mercaptopropyltrimethoxysilane.

[0048] The alkoxysilane may include not only trialkoxysilane but also dialkoxysilane and monoalkoxysilane. The alkoxysilane is preferably composed of at least one of monoalkoxysilane, dialkoxysilane, and trialkoxysilane. The trialkoxysilane, dialkoxysilane, and monoalkoxysilane may have the same functional group, or may have different functional groups. The alkoxysilane is preferably composed of two or more alkoxysilanes having different functional groups. By including dialkoxysilane or monoalkoxysilane, the crosslinking degree of silsesquioxane obtained by copolymerization can be controlled, and the viscosity of the obtained curable resin composition can be controlled, and the viscosity can be adjusted according to the manufacturing process. The type and ratio of these alkoxysilanes are not particularly limited and can be appropriately selected according to the purpose. The alkoxysilane is preferably composed of one or more reactive substituents of vinyl group, acrylic group, methacrylic group, hydroxyl group, phenolic hydroxyl group, epoxy group, and glycidyl group as a functional group.

[0049] The curable resin composition of the present invention is a mixture of a silsesquioxane polymer and a thermosetting resin, and the thermosetting resin is composed of a polymer as a base polymer and a polymerization initiator, and may further contain a solvent, a polymerizable crosslinking agent, a photoacid generator, an antioxidant, a light scattering agent, etc. The thermosetting resin is preferably an acrylic resin having a (meth)acryloyl group in a side chain or an acid crosslinking group-containing silicone resin. As the polymer, a polymer derived from acrylic acid, methacrylic acid, an acrylic acid ester, or a methacrylic acid ester, a copolymer combining a plurality of polymers, a polymer having glycidyl (meth)acrylate as a repeating unit, a polymer containing a siloxane skeleton, a urethane skeleton, a silphenylene skeleton, a norbornene skeleton, a fluorene skeleton, or an isocyanurate skeleton can be suitably used, and the polymer to be used may be selected according to the application. Examples of the polymerizable groups include acrylic resins, alkyd resins, melamine resins, epoxy resins, silicone resins, polyvinyl alcohols, polyvinylpyrrolidones, polyamides, polyamide-imides, polyimides, and other polyimide precursors and their esterification products, and reaction products of tetracarboxylic dianhydrides and diamines. Polymerizable substituents are introduced into these polymers, and they can be cured by using them in combination with a polymerization initiator. Examples of radically polymerizable substituents include vinyl groups, acrylic groups, methacrylic groups, and thiol groups, and all of these groups can be used suitably. Examples of cationic polymerizable substituents include hydroxyl groups, phenolic hydroxyl groups, epoxy groups, glycidyl groups, oxetanyl groups, and isocyanate groups, and all of these groups can be used suitably.

[0050] The curable resin composition of the present invention also preferably contains a polymerization initiator. The polymerization initiator may be a thermal polymerization initiator, any of which may be suitably used in accordance with the base polymer. Examples of the thermal polymerization initiator include AIBN, BPO, TA-100, and IK-1 (manufactured by San-Apro Co., Ltd.). In addition, the curable resin composition may contain a known thermal radical polymerization initiator or a thermal cationic polymerization initiator, and is not particularly limited. The content of the polymerization initiator is preferably 0.1 to 10 parts by mass, and more preferably 0.2 to 5 parts by mass, based on 100 parts by mass of the polymer to be added.

[0051] The curable resin composition of the present invention may contain a solvent to improve its coating properties. As the solvent, an organic solvent is preferable from the viewpoint of dispersibility with the quantum dots, and examples thereof include ketones, alkylene glycol ethers, alcohols, and aromatic compounds. From the group of ketones, acetone, methyl ethyl ketone, cyclohexanone, etc., and from the group of alkylene glycol ethers, methyl cellosolve (ethylene glycol monomethyl ether), butyl cellosolve (ethylene glycol monobutyl ether), methyl cellosolve acetate, cellosolve acetate, butyl cellosolve acetate, ethylene glycol monopropyl ether, ethylene glycol monohexyl ether, ethylene glycol dimethyl ether, diethylene glycol ethyl ether, diethylene glycol diethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, propylene glycol monomethyl ether acetate, diethylene glycol ... Suitable examples of the alcohols that can be used include methyl alcohol, ethyl alcohol, isopropyl alcohol, n-butyl alcohol, and 3-methyl-3-methoxybutanol, as well as benzene, toluene, and xylene from the aromatic compound group.

[0052] The curable resin composition of the present invention may further contain a polymerizable crosslinking agent, an antioxidant, a light scattering agent, and the like.

[0053] By mixing the above-mentioned thermosetting resin with a silsesquioxane polymer in which quantum dots are copolymerized with silsesquioxane, or a silsesquioxane polymer in which quantum dots are copolymerized with alkoxysilane, a curable resin composition containing the desired quantum dots can be obtained. The content of the quantum dots can be appropriately adjusted depending on the desired light emission characteristics. The concentration of the quantum dots is preferably adjusted so that the absorptance of the excitation light is 90% or more. Although the optimal concentration varies depending on the characteristics of the quantum dots, it is particularly preferable that the concentration is 10 parts by mass or more relative to 100 parts by mass of the curable resin composition.

[0054] A wavelength converting material for color filters can be obtained by applying the curable resin composition containing the quantum dots produced by the above method onto a substrate, exposing and developing it. The method for producing the wavelength converting material is not particularly limited and can be appropriately selected according to the required properties and processes. For example, the wavelength converting material can be obtained by applying the curable resin composition onto a transparent film or substrate material such as PET or polyimide, and curing it. To apply the material to a transparent film, a spraying method such as a spray or inkjet, a spin coater or a bar coater can be used.

[0055] The method for curing the curable resin composition is not particularly limited, but for example, the curable resin composition can be cured by heating the film coated with the curable resin composition at 60° C. for 2 hours and then at 150° C. for 4 hours. The method can be appropriately changed depending on the application. EXAMPLES

[0056] The present invention will be described in detail below using examples and comparative examples, but the present invention is not limited to these. In these examples, InP / ZnSe / ZnS core-shell quantum dots were used as the quantum dot material.

[0057] (Quantum dot core synthesis process) 0.23g (0.9mmol) of palmitic acid, 0.088g (0.3mmol) of indium acetate, and 10mL of 1-octadecene were added to the flask, and the mixture was heated and stirred at 100℃ under reduced pressure to dissolve the raw materials and degassed for 1 hour. After that, nitrogen was purged into the flask, and 0.75mL (0.15mmol) of a solution prepared by mixing tristrimethylsilylphosphine with trioctylphosphine to adjust the concentration to 0.2M was added, and the temperature was raised to 300℃. It was confirmed that the solution turned from yellow to red and that core particles were formed.

[0058] (Quantum dot shell layer synthesis process) Next, 2.85g (4.5mmol) of zinc stearate and 15mL of 1-octadecene were added to another flask, and the mixture was heated and stirred at 100°C under reduced pressure to dissolve and degassed for 1 hour to prepare a 0.3M zinc stearate octadecene solution. 3.0mL (0.9mmol) was added to the reaction solution after the core synthesis and cooled to 200°C. Next, 0.474g (6mmol) of selenium and 4mL of trioctylphosphine were added to another flask and heated to 150°C to dissolve, preparing a 1.5M selenium trioctylphosphine solution. The reaction solution after the core synthesis step, which had been cooled to 200°C, was heated to 320°C over 30 minutes, while the selenium trioctylphosphine solution was added in 0.1mL increments to a total of 0.6mL (0.9mmol), and the mixture was held at 320°C for 10 minutes and then cooled to room temperature. 0.44 g (2.2 mmol) of zinc acetate was added and dissolved by heating and stirring at 100°C under reduced pressure. The flask was purged again with nitrogen and heated to 230°C, and 0.98 mL (4 mmol) of 1-dodecanethiol was added and held for 1 hour. The resulting solution was cooled to room temperature to produce a solution containing core-shell quantum dots consisting of InP / ZnSe / ZnS.

[0059] (Surface treatment of quantum dots) After the reaction was completed, the solution was cooled to room temperature, ethanol was added to precipitate the reaction solution, and the solution was centrifuged to remove the supernatant. The same purification was repeated and the solution was dispersed in toluene. The toluene solution of the quantum dots was placed in a flask with nitrogen replaced. 0.24 mL (1.0 mmol) of (3-mercaptopropyl)triethoxysilane was added to the solution and stirred at room temperature for 24 hours.

[0060] (Silsesquioxane copolymerization process) In a nitrogen-substituted flask, 10 mL of (3-methacryloyloxypropyl)trimethoxysilane, 20 mL of toluene, and 10 mL of methanol were mixed, and 4.0 mL of 1.0 N hydrochloric acid was added dropwise in small amounts while stirring at room temperature. After the addition, the mixture was stirred at room temperature for 60 minutes, and the solution temperature was raised to 60°C and refluxed for 60 minutes. The system was then evacuated for 2 hours at 60°C to distill off the solvent. Silsesquioxane with methacryl groups was obtained in the flask.

[0061] (Copolymerization of quantum dots and silsesquioxane) The obtained silsesquioxane and the surface-treated quantum dot solution were added to a nitrogen-substituted flask so that the solid concentration was 20 parts by mass, and 20 mL of toluene and 10 mL of methanol were further added and mixed. 4.0 mL of 1.0 N hydrochloric acid was added dropwise at room temperature while stirring. After the dropwise addition, the mixture was stirred at room temperature for 60 minutes, and then the solution temperature was increased to 60°C and the mixture was allowed to react for 60 minutes under reflux. After that, the solvent was distilled off while nitrogen was flowing through the system at 40°C, yielding the quantum dot / silsesquioxane copolymer 1.

[0062] (Copolymerization of quantum dots and alkoxysilane 1) In a nitrogen-substituted flask, 7 mL of (3-methacryloyloxypropyl)trimethoxysilane, 3 mL of ethoxytrimethylsilane, and the surface-treated quantum dot solution were added so that the solid concentration was 20 parts by mass, and then 20 mL of toluene and 10 mL of methanol were added and mixed. 4.0 mL of 1.0 N hydrochloric acid was added dropwise to the mixture at room temperature while stirring. After the dropwise addition, the mixture was stirred at room temperature for 60 minutes, and then the solution temperature was increased to 60°C and the mixture was allowed to react for 60 minutes under reflux. After that, the solvent was distilled off while nitrogen was flowing through the system at 40°C, yielding the quantum dot / silsesquioxane copolymer 2.

[0063] (Copolymerization of quantum dots and alkoxysilanes 2) In a nitrogen-substituted flask, 4 mL of (3-methacryloyloxypropyl)trimethoxysilane, 3 mL of phenyltrimethoxysilane, 3 mL of ethoxytrimethylsilane, and the surface-treated quantum dot solution were added so that the solid concentration was 20 parts by mass, and then 20 mL of toluene and 10 mL of methanol were added and mixed. 4.0 mL of 1.0 N hydrochloric acid was added dropwise to the mixture at room temperature while stirring. After the dropwise addition, the mixture was stirred at room temperature for 60 minutes, and then the solution temperature was increased to 60° C. and the mixture was allowed to react for 60 minutes under reflux. After that, the solvent was distilled off while nitrogen was flowing through the system at 40° C., yielding the quantum dot / silsesquioxane copolymer 3.

[0064] Example 1 The quantum dot / silsesquioxane copolymer 1 and acrylic resin RA-4101 (Negami Sangyo Co., Ltd.) were weighed out so that the non-volatile component ratio contained 20 parts by mass of quantum dots, and 1 part by mass of AIBN was weighed out and mixed for every 100 parts by mass of the acrylic resin non-volatile component.

[0065] Example 2 The quantum dot / silsesquioxane copolymer 2 and acrylic resin RA-4101 (Negami Sangyo Co., Ltd.) were weighed out so that the non-volatile component ratio contained 20 parts by mass of quantum dots, and 1 part by mass of AIBN was weighed out and mixed for every 100 parts by mass of the acrylic resin non-volatile component.

[0066] Example 3 The quantum dot / silsesquioxane copolymer 3 and acrylic resin RA-4101 (Negami Sangyo Co., Ltd.) were weighed out so that the non-volatile component ratio contained 20 parts by mass of quantum dots, and 1 part by mass of AIBN was weighed out and mixed for every 100 parts by mass of the acrylic resin non-volatile component.

[0067] Example 4 Copolymer 1 of quantum dots and silsesquioxane and epoxy-containing silicone resin (Shin-Etsu Chemical, CAS No. 2253674-54-1) were weighed and mixed so that the non-volatile component ratio contained 20 parts by mass of quantum dots. 2 parts by mass of thermal acid generator TA-100 and 20 parts by mass of crosslinker THI-DE were weighed and mixed for 100 parts by mass of silicone resin non-volatile component.

[0068] Example 5 The quantum dot / silsesquioxane copolymer 2 and epoxy-containing silicone resin (Shin-Etsu Chemical, CAS No. 2253674-54-1) were weighed and mixed so that the non-volatile component ratio contained 20 parts by mass of quantum dots. 2 parts by mass of the thermal acid generator TA-100 and 20 parts by mass of the crosslinker THI-DE were weighed and mixed for 100 parts by mass of the silicone resin non-volatile component.

[0069] Example 6 The quantum dot / silsesquioxane copolymer 3 and epoxy-containing silicone resin (Shin-Etsu Chemical, CAS No. 2253674-54-1) were weighed and mixed so that the non-volatile component ratio contained 20 parts by mass of quantum dots. 2 parts by mass of the thermal acid generator TA-100 and 20 parts by mass of the crosslinker THI-DE were weighed and mixed for 100 parts by mass of the silicone resin non-volatile component.

[0070] Comparative Example 1 The quantum dots that had only been surface-treated and acrylic resin RA-4101 (Negami Sangyo Co., Ltd.) were weighed out so that the non-volatile component ratio contained 20 parts by mass of quantum dots, and 1 part by mass of AIBN was weighed out and mixed for every 100 parts by mass of the acrylic resin non-volatile component.

[0071] Comparative Example 2 The quantum dots that had only been surface-treated and epoxy-containing silicone resin (Shin-Etsu Chemical, CAS No. 2253674-54-1) were weighed and mixed so that the non-volatile component ratio contained 20 parts by mass of quantum dots. 2 parts by mass of thermal acid generator TA-100 and 20 parts by mass of crosslinker THI-DE were weighed and mixed for 100 parts by mass of silicone resin non-volatile component.

[0072] Wavelength converting materials were produced using the quantum dot-containing curable resin compositions obtained in Examples 1 to 6 and Comparative Examples 1 and 2. The quantum dot-containing curable resin compositions were applied onto a glass substrate, and after removing the solvent, a semiconductor nanoparticle resin layer having a thickness of 50 μm was formed using a bar coater. The semiconductor nanoparticle resin layer was further cured by heating at 120° C. for 5 minutes, thereby producing a wavelength converting material.

[0073] (Dispersibility evaluation) The presence of aggregates in the cured resin film was confirmed by an optical microscope. The presence of aggregates of 1 μm or more in size was rated as ×, and the absence of aggregates or the presence of aggregates of less than 1 μm in size was rated as ◯.

[0074] (Cure Evaluation) The curability of the resin cured film was evaluated by measuring the spectrum before and after curing using a Fourier transform infrared spectrophotometer (JASCO Corporation FT / IR-4600), and the curing rate was calculated from the change in peak height attributable to the functional group related to curing. The curing rate was defined by (Equation 1) where the peak intensity before curing is A1 and the peak intensity after curing is A2. (Formula 1) Curing rate (%)=(A1-A2) / A1×100 The curing rates were calculated using acrylic groups as the functional group in Examples 1-3 and Comparative Example 1, and epoxy groups as the functional group in Examples 4-6 and Comparative Example 2.

[0075] (Evaluation of luminescence properties) The emission characteristics of the wavelength conversion material were evaluated using a quantum efficiency measurement system (QE-2100) manufactured by Otsuka Electronics Co., Ltd. to measure the emission wavelength, fluorescence emission half-width, and fluorescence emission efficiency (internal quantum efficiency) of the quantum dots at an excitation wavelength of 450 nm.

[0076] (Reliability evaluation) The obtained pattern was treated at 85° C. and 85% RH (relative humidity) for 250 hours, and the quantum yield after treatment was measured to confirm the rate of decrease from the initial state and evaluate its reliability.

[0077] Table 1 shows the fluorescence efficiency values ​​after the wavelength converting materials of the examples and comparative examples were produced, and the fluorescence efficiency values ​​after the reliability evaluation.

[0078] [Table 1]

[0079] From the results in Table 1, it was confirmed that aggregation occurred in the comparative example, which was accompanied by a long-wavelength shift in the emission wavelength and an increase in the half-width. Furthermore, a decrease in quantum yield and a deterioration in emission intensity due to a reliability test were confirmed.

[0080] On the other hand, no aggregates were observed in the Examples, and it is believed that changes in the luminescence characteristics were suppressed. In addition, when comparing the reliability test results, it is found that the Examples all have improved stability compared to the Comparative Examples, and that changes over time are suppressed.

[0081] As described above, it has been confirmed that by using the curable resin composition of the present invention, a wavelength converting material having stable light emitting characteristics and high reliability can be obtained.

[0082] The present specification includes the following aspects. [1]: A curable resin composition containing quantum dots, characterized in that the curable resin composition is a mixture of a silsesquioxane polymer in which the quantum dots are copolymerized with silsesquioxane, and a thermosetting resin. [2]: A curable resin composition containing quantum dots, characterized in that the curable resin composition is a mixture of a silsesquioxane polymer in which the quantum dots and an alkoxysilane are copolymerized, and a thermosetting resin. [3]: The curable resin composition according to [1] or [2] above, wherein the surfaces of the quantum dots are surface-modified with a silane coupling agent. [4]: The curable resin composition according to [2] above, wherein the alkoxysilane comprises two or more kinds of alkoxysilanes each having a different functional group. [5]: The curable resin composition according to [2] or [4] above, characterized in that the alkoxysilane comprises at least one kind of alkoxysilane selected from the group consisting of monoalkoxysilane, dialkoxysilane, and trialkoxysilane. [6]: The curable resin composition according to [3] above, wherein the silane coupling agent has at least one of an amino group, a thiol group, a carboxy group, a phosphino group, a phosphine oxide group, and an ammonium ion. [7]: The curable resin composition according to [1] above, characterized in that the silsesquioxane has, as a functional group, one or more reactive substituents selected from the group consisting of a vinyl group, an acrylic group, a methacrylic group, a hydroxyl group, a phenolic hydroxyl group, an epoxy group, and a glycidyl group. [8]: The curable resin composition according to [2] above, characterized in that the alkoxysilane has, as a functional group, one or more reactive substituents selected from the group consisting of a vinyl group, an acrylic group, a methacrylic group, a hydroxyl group, a phenolic hydroxyl group, an epoxy group, and a glycidyl group. [9]: The curable resin composition according to [1], [2], [3], [4], [5], [6], [7] or [8], characterized in that the thermosetting resin is an acrylic resin having a (meth)acryloyl group in a side chain.

[10] : The curable resin composition according to [1], [2], [3], [4], [5], [6], [7] or [8], characterized in that the thermosetting resin is an acid crosslinkable group-containing silicone resin.

[0083] The present invention is not limited to the above-described embodiment. The above-described embodiment is merely an example, and anything that has substantially the same configuration as the technical idea described in the claims of the present invention and exhibits similar effects is included in the technical scope of the present invention.

Claims

1. A curable resin composition containing quantum dots, characterized in that the curable resin composition is a mixture of a silsesquioxane polymer in which the quantum dots are copolymerized with silsesquioxane, and a thermosetting resin.

2. A curable resin composition containing quantum dots, characterized in that the curable resin composition is a mixture of a silsesquioxane polymer in which the quantum dots and an alkoxysilane are copolymerized, and a thermosetting resin.

3. 2. The curable resin composition according to claim 1, wherein the surfaces of the quantum dots are modified with a silane coupling agent.

4. 3. The curable resin composition according to claim 2, wherein the surfaces of the quantum dots are surface-modified with a silane coupling agent.

5. 3. The curable resin composition according to claim 2, wherein the alkoxysilane comprises two or more kinds of alkoxysilanes each having a different functional group.

6. 3. The curable resin composition according to claim 2, wherein the alkoxysilane comprises at least one of monoalkoxysilane, dialkoxysilane, and trialkoxysilane.

7. 6. The curable resin composition according to claim 5, wherein the alkoxysilane comprises at least one of monoalkoxysilane, dialkoxysilane, and trialkoxysilane.

8. 4. The curable resin composition according to claim 3, wherein the silane coupling agent has at least one of an amino group, a thiol group, a carboxy group, a phosphino group, a phosphine oxide group, and an ammonium ion.

9. 5. The curable resin composition according to claim 4, wherein the silane coupling agent has at least one of an amino group, a thiol group, a carboxy group, a phosphino group, a phosphine oxide group, and an ammonium ion.

10. The curable resin composition according to claim 1, characterized in that the silsesquioxane has, as a functional group, one or more reactive substituents selected from the group consisting of a vinyl group, an acrylic group, a methacrylic group, a hydroxyl group, a phenolic hydroxyl group, an epoxy group, and a glycidyl group.

11. The curable resin composition according to claim 2, characterized in that the alkoxysilane has, as a functional group, one or more reactive substituents selected from the group consisting of a vinyl group, an acrylic group, a methacrylic group, a hydroxyl group, a phenolic hydroxyl group, an epoxy group, and a glycidyl group.

12. 12. The curable resin composition according to claim 1, wherein the thermosetting resin is an acrylic resin having a (meth)acryloyl group in a side chain.

13. 12. The curable resin composition according to claim 1, wherein the thermosetting resin is an acid crosslinkable group-containing silicone resin.