Dispersions, compositions, sealing components, light-emitting devices, lighting fixtures, display devices, methods for manufacturing dispersions, and methods for surface modification of metal oxide particles.

Abstract

The dispersion involved in this invention contains metal oxide particles surface-modified using at least one silane compound containing a methyl group and a hydrocarbon group having two or more carbon atoms, and at least one silicone compound. For the metal oxide particles obtained by vacuum drying the dispersion, FT-IR measurements at 800 cm⁻¹ are performed. ‑1 Above and 3800cm ‑1 The following wavenumber range of transmission spectra, after normalizing the transmission spectral values, satisfies the following equation (1): IA / IB ≤ 3.5 (1). “IA” is 3500 cm⁻¹ ‑1 The standardized spectral value, "IB", is 1100 cm⁻¹. ‑1 The standardized spectral values ​​below.

Description

TECHNICAL FIELD

[0001] The present application relates to a dispersion liquid, a composition, a sealing member, a light-emitting device, a lighting appliance, a display device, a method for producing a dispersion liquid, and a method for surface modification of metal oxide particles, which contain metal oxide particles surface-modified with a silane compound and a silicone compound.

[0002] This application claims priority based on Japanese Patent Application No. 2020-165259 filed on September 30, 2020, and the contents thereof are incorporated herein. BACKGROUND

[0003] As a light source having advantages of small size, long life, low voltage driving, and the like, a light-emitting diode (LED) is widely used. An LED chip in an LED package is generally sealed with a sealing material containing a resin in order to prevent contact with a deteriorating factor existing in an external environment such as oxygen, moisture, and the like. Therefore, light emitted from the LED chip is emitted to the outside through the sealing material. Therefore, in order to increase the light beam emitted from the LED package, it is important to efficiently extract light emitted from the LED chip to the outside of the LED package.

[0004] As a sealing material for improving the extraction efficiency of light emitted from an LED chip, a light-scattering composite formation composition containing metal oxide particles surface-modified with a surface modification material containing at least one functional group selected from an alkenyl group, an H-Si group, and an alkoxy group, and a base resin composition is known (for example, refer to Patent Literature 1).

[0005] In this light-scattering composite formation composition, a dispersion liquid containing metal oxide particles is mixed in a silicone resin while maintaining transparency. As the metal oxide particles, particles having a small dispersion particle diameter and a high refractive index are used. By this structure, the light-scattering composite obtained by curing the light-scattering composite formation composition suppresses a decrease in light transmittance and improves light scattering properties.

[0006] PRIOR ART DOCUMENTS

[0007] PATENT LITERATURE

[0008] Patent Literature 1: International Publication No. 2016 / 142992 SUMMARY

[0009] PROBLEMS TO BE SOLVED BY THE INVENTION

[0010] However, silicone resins used as sealing materials for LEDs generally contain methyl groups and phenyl groups as hydrocarbon groups, and the ratio of functional groups is adjusted according to the use. For example, in lighting applications, in order to increase the amount of light extraction from LED chips, a structure containing a large amount of phenyl groups having a high refractive index is adopted. On the other hand, in vehicle-mounted applications, in order to suppress the deterioration of silicone sealing resins caused by high-output LEDs, a structure containing a large amount of methyl groups having a high heat resistance is adopted.

[0011] Therefore, the surface modification of metal oxide particles needs to be designed according to each type or each use of silicone sealing resins.

[0012] Furthermore, in recent years, in order to increase the life of LEDs, the demand for methyl-based silicone resins containing a large amount of methyl groups having a high heat resistance has increased. Methyl-based silicone resins have a large content of methyl groups and a large degree of hydrophobicity compared to phenyl-based silicone resins and the like that have been generally used in the past. Therefore, even metal oxide particles whose surfaces are hydrophobized as in the invention described in Patent Document 1, when mixed with methyl-based silicone resins, the metal oxide particles coagulate with each other, and there is a problem in that a transparent composition cannot be obtained.

[0013] In order to solve the problems as described above, a method of obtaining metal oxide particles whose surfaces are modified so as to be dispersible in methyl-based silicone resins by performing primary modification of dispersing metal oxide particles directly in a silane compound and then performing secondary modification of silicone compounds was investigated. Hereinafter, "metal oxide particles whose surfaces are modified" will be sometimes referred to simply as "surface-modified metal oxide particles".

[0014] However, the surface-modified metal oxide particles obtained by the above method cannot be dispersed in phenyl-based silicone resins containing a large amount of phenyl groups.

[0015] Therefore, surface-modified metal oxide particles that can be dispersed in both methyl-based silicone resins and phenyl-based silicone resins are needed.

[0016] The present application was made in order to solve the above problems, and aims to provide a dispersion liquid containing surface-modified metal oxide particles that can be dispersed in both methyl-based silicone resins and phenyl-based silicone resins, a composition containing the dispersion liquid, a sealing member formed using the composition, a light-emitting device having the sealing member, a lighting appliance and a display device provided with the light-emitting device, a method of manufacturing the dispersion liquid, and a method of modifying the surfaces of the metal oxide particles.

[0017] Approach to solving the problem

[0018] To solve the above problems, a first aspect of the present application provides a dispersion liquid containing metal oxide particles surface-modified with at least one silane compound and at least one silicone compound, and a solvent, wherein

[0019] The silane compound contains a methyl group and a hydrocarbon group having 2 or more carbon atoms,

[0020] The molar ratio of the methyl group to the hydrocarbon group (methyl / hydrocarbon group) in the metal oxide particles is 0.01 or more and 10 or less,

[0021] For the metal oxide particles obtained by drying the dispersion liquid by vacuum drying, the transmission spectrum in the wave number range of 800 cm -1 and 3800 cm -1 When the transmission spectrum values in the above wave number ranges are normalized so that the maximum value of the transmission spectrum in the range is 100 and the minimum value is 0, the following formula (1) is satisfied.

[0022] IA / IB≤3.5 (1)

[0023] (In the formula, "IA" represents the normalized spectrum value at 3500 cm -1 , and "IB" represents the normalized spectrum value at 1100 cm -1 .)

[0024] In the first aspect of the present application, the hydrocarbon group having 2 or more carbon atoms can be an aromatic hydrocarbon group.

[0025] To solve the above problems, a second aspect of the present application provides a composition containing the above dispersion liquid and a silicone resin component.

[0026] To solve the above problems, a third aspect of the present application provides a sealing member which is a cured product of the above composition.

[0027] To solve the above problems, a fourth aspect of the present application provides a light emitting device provided with the above sealing member and a light emitting element sealed by the above sealing member.

[0028] To solve the above problems, a fifth aspect of the present application provides a lighting appliance provided with the above light emitting device.

[0029] To solve the above problems, a sixth aspect of the present application provides a display device provided with the above light emitting device.

[0030] To solve the above problems, a seventh aspect of the present application provides a method for producing the dispersion liquid of the first aspect.

[0031] To solve the above problems, an eighth aspect of the present application provides a method for surface-modifying metal oxide particles.

[0032] Effects of the Invention

[0033] According to the present application, it is possible to provide a dispersion liquid containing surface-modified metal oxide particles that can be dispersed in both a methyl-based silicone resin and a phenyl-based silicone resin, a composition containing the dispersion liquid, a sealing member formed using the composition, a light-emitting device having the sealing member, a lighting appliance provided with the light-emitting device, a display device, a method for manufacturing the dispersion liquid, and a method for surface-modifying metal oxide particles. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 is a schematic diagram showing a preferable example of a light-emitting device according to the present application.

[0035] Figure 2 is a schematic diagram showing another preferable example of a light-emitting device according to the present application.

[0036] Figure 3 is a schematic diagram showing another preferable example of a light-emitting device according to the present application.

[0037] Figure 4 is a schematic diagram showing another preferable example of a light-emitting device according to the present application. DETAILED DESCRIPTION

[0038] Examples of preferable embodiments of the dispersion liquid, the composition containing the dispersion liquid, the sealing member formed using the composition, the light-emitting device having the sealing member, the lighting appliance provided with the light-emitting device, the display device, the method for manufacturing the dispersion liquid, and the method for surface-modifying metal oxide particles according to the present application are described.

[0039] In addition, the present embodiment is described in detail in order to better understand the gist of the present application, and the present application is not limited unless specifically specified. For example, unless specifically limited, materials, amounts, types, numbers, dimensions, ratios, orders, times, temperatures, and the like can be changed, added, and omitted as needed.

[0040] <1. Idea of the Inventors>

[0041] First, before the present application is described in detail, the idea of the inventors who completed the present application is described.

[0042] Generally, in the production of a sealing material (composition) as a raw material for a sealing member, metal oxide particles are modified with a surface modifying material and dispersed in a resin such as a silicone resin. However, a methyl-based silicone resin has a large content of methyl groups and a large degree of hydrophobicity as compared with a phenyl-based silicone resin and the like that have been generally used in the past. Therefore, as described above, even in the case where metal oxide particles modified with a surface modifying material are used, the metal oxide particles are difficult to uniformly disperse in a methyl-based silicone resin.

[0043] Therefore, the present inventors and the like conducted intensive studies in order to solve the problem. As a result, it was found that even if the amount of the surface modifying material is simply increased, the dispersibility of the metal oxide particles in the methyl-based silicone resin does not substantially improve.

[0044] Upon obtaining this result, the present inventors and the like further conducted studies, focusing on the modification state of the surface modifying material in the surface of the metal oxide particles. And, the studies were conducted based on the following idea. That is, it was assumed that even in the case where the metal oxide particles are modified with a large amount of the surface modifying material, if only a small amount of the surface modifying material is attached to the surface of the metal oxide particles, the surface of the metal oxide particles is not sufficiently hydrophobized. On the other hand, it was assumed that even in the case where the metal oxide particles are modified with a small amount of the surface modifying material, if the proportion of the surface modifying material attached to the surface of the metal oxide particles is high, when a large amount of the surface modifying material is attached to the surface of the metal oxide particles, the surface of the metal oxide particles is sufficiently hydrophobized.

[0045] And, the present inventors et al. found that, in the case where a silane compound or a silicone compound is used as a surface modification material, the degree of adhesion of the surface modification material to the metal oxide particle as described above can be measured and observed using a Fourier transform infrared spectrophotometer (FT-IR). And it was found that, if the metal oxide particle is surface-modified with a silane compound and a silicone compound, the metal oxide particle can be dispersed in a methyl-based silicone resin which has been difficult to disperse in the past. And it was found that, if the metal oxide particle is secondarily modified with a silane compound instead of a silicone compound, it can also be dispersed in a methyl-based silicone resin, and further, it can also be dispersed in a phenyl-based silicone resin. And it was found that, by tertiary modification with a silicone compound, the viscosity increase of the composition described later can be suppressed, and the brightness of an LED can be improved. And it was also found that, by the method described later, the silane compound can be sufficiently adhered to the surface of the metal oxide particle. And it was found that, by adjusting the functional group ratio of the silane compound and the silicone compound so that the molar ratio of the methyl group to the hydrocarbon group in the metal oxide particle (methyl / hydrocarbon group) becomes 0.01 or more and 10 or less, a surface-modified metal oxide particle having high versatility which can be dispersed in both a methyl-based silicone resin and a phenyl-based silicone resin can be obtained. Hereinafter, the combination of secondary modification and tertiary modification will be sometimes referred to simply as secondary modification.

[0046] <2. Dispersion liquid>

[0047] A dispersion liquid according to the present embodiment will be described.

[0048] The dispersion liquid according to the present embodiment contains a metal oxide particle surface-modified with at least one silane compound and at least one silicone compound, and a solvent, the silane compound containing a methyl group and a hydrocarbon group having 2 or more carbon atoms, the ratio of the methyl group to the hydrocarbon group in the metal oxide particle (methyl / hydrocarbon group) being 0.01 or more and 10 or less.

[0049] In the present embodiment, for the metal oxide particle obtained by drying the dispersion liquid by vacuum drying, the transmission spectrum in the wave number range of 800 cm -1 and 3800 cm -1 When the transmission spectrum value measured is standardized so that the maximum value of the transmission spectrum in the range becomes 100 and the minimum value becomes 0, the following equation (1) is satisfied.

[0050] IA / IB≤3.5 (1)

[0051] (In the equation, "IA" represents the standardized spectrum value at 3500 cm -1 , and "IB" represents the standardized spectrum value at 1100 cm-1

[0052] By satisfying the above conditions, the dispersion liquid according to the present embodiment can be dispersed in both the methyl-based silicone resin and the phenyl-based silicone resin. Also, the viscosity of the dispersed methyl-based silicone resin or phenyl-based silicone resin can be inhibited from increasing. Also, the brightness of the LED can be improved.

[0053] Specifically, in the transmission spectrum measured using a Fourier transform infrared spectrophotometer, the position at a wave number of 1100 cm -1 is attributed to a siloxane bond (Si-O-Si bond), and the position at a wave number of 3500 cm -1 is attributed to a silanol group (Si-OH group). The silane compound and the silicone compound each contain a Si-OH group that can form a Si-O-Si bond and a group that can form a Si-OH group. Therefore, by comparing the spectrum value (IA) at 3500 cm -1 with the spectrum value (IB) at 1100 cm -1 , the reaction degree of the Si-OH of the silane compound and the silicone compound, or the group that can form a Si-OH group can be observed.

[0054] Also, the inventors have found that, in the case where IA / IB is 3.5 or less, the silane compound is sufficiently attached to the surface of the metal oxide particles. By this feature, the metal oxide particles do not agglomerate even when mixed with the methyl-based silicone resin, and can be dispersed in the methyl-based silicone resin.

[0055] In contrast, in the case where IA / IB exceeds 3.5, the silane compound and the silicone compound are not sufficiently attached to the surface of the metal oxide particles, and the dispersibility of the metal oxide particles in the methyl-based silicone resin is not excellent. As a result, when the dispersion liquid and the methyl-based silicone resin are mixed, there is a tendency for the metal oxide particles to agglomerate, and for turbidity to occur in the obtained composition. IA / IB is 3.5 or less as described above, is preferably 3.0 or less, more preferably 2.5 or less, and further preferably 2.0 or less.

[0056] Also, the lower limit value of IA / IB is preferably IA = 0, and is therefore 0. However, even if a small amount of silanol group (Si-OH group) remains, the methyl-based silicone resin can be mixed, and therefore the lower limit value of IA / IB can be 0, can be 0.1, can be 0.2, can be 0.5, can be 0.8, can be 1.0, or can be 1.5.

[0057] In addition, regarding the measurement of the transmission spectrum of the metal oxide particles using a Fourier transform infrared spectrophotometer (FT-IR), specifically, can be performed as follows.​

[0058] The dispersion liquid of the present embodiment is dried by vacuum drying. The drying conditions are appropriately adjusted according to the amount and concentration of the dispersion liquid. For example, if the solid content is 30 mass% of a dispersion liquid 10 g, drying at 100°C or lower under 20 hPa for 2 hours or more is sufficient. As a vacuum drying machine, for example, a VACUUM OVEN VOS-201SD manufactured by EYELA TOKYO RIKAKIKAI CO, LTD. can be used.

[0059] Next, by using 0.01 g to 0.05 g of the metal oxide particles obtained by drying, measurement can be performed using a Fourier transform infrared spectrophotometer (for example, manufactured by JASCO Corporation, model: FT / IR-670Plus).

[0060] However, even if the surface-modified metal oxide particles of the related art are those in which IA / IB is 3.5 or less, they can be dispersed in a methyl-based silicone resin, but it is difficult to disperse them in a phenyl-based silicone resin.

[0061] The present inventors and others have learned that if a silane compound containing a methyl group and a hydrocarbon group having 2 or more carbon atoms is used, and the metal oxide particles are surface-modified by the surface modification method described below, surface-modified metal oxide particles that can be dispersed in both a methyl-based silicone resin and a phenyl-based silicone resin can be obtained, and that by surface-modifying with a silicone, the viscosity increase of the composition described below can be suppressed, and the brightness of an LED can be improved.

[0062] The detailed mechanism of how the metal oxide particles surface-modified only with a silane compound containing a methyl group and a hydrocarbon group having 2 or more carbon atoms can be dispersed in both a methyl-based silicone resin and a phenyl-based silicone resin is not clear, but it is presumed as follows.

[0063] In the present embodiment, as described later, the initial surface modification (primary modification) of the metal oxide particles is performed in a high concentration of the silane compound. By performing such a primary modification before the secondary modification, both the silane compound of the primary modification and the surface modification material of the surface modification (secondary modification) performed next are sufficiently attached to the surface of the metal oxide particles. Here, if a silicone compound is selected as the surface modification material of the secondary modification, a large amount of silicone chains that can become steric hindrances will exist on the surface of the metal oxide particles. Therefore, such metal oxide particles are not subjected to dense surface treatment, and as a result, it is presumed that the metal oxide particles subjected to the secondary modification with a silicone compound are difficult to disperse in a silicone resin.

[0064] On the other hand, in the case where secondary modification is performed using a silane compound, the silane compound does not have a steric hindrance like a silicone compound, and is more likely to adhere to the metal oxide particles. Therefore, it is presumed that the metal oxide particles are densely surface-modified with the silane compound. That is, the metal oxide particles of the present embodiment have more silane compounds adhered thereto and are densely surface-modified as compared with conventional ones, and are thus presumed to be easily dispersed in a silicone resin for an LED.

[0065] The present inventors et al. consider that, in order to disperse the metal oxide particles in a silicone resin for an LED, surface modification must be performed using both a silane compound and a silicone compound. Therefore, the result that surface modification is easily mixed with various silicone resins when only primary modification and secondary modification are performed using a specific silane compound is unexpected.

[0066] In the present embodiment, it is preferable to perform primary modification or secondary modification using only a silane compound, and further perform tertiary modification using a silicone compound.

[0067] In the case where tertiary modification is further performed using a silicone compound after the secondary modification, the viscosity of the composition can be inhibited from increasing, and the mechanism of the improvement in the brightness of the LED is not clear, but is presumed as follows. The present inventors et al. observed metal oxide particles surface-modified by primary modification and secondary modification using a silane compound containing a methyl group and a hydrocarbon group having 2 or more carbon atoms, and metal oxide particles further surface-modified by tertiary modification using a silicone compound, using a transmission electron microscope. The metal oxide particles of the metal oxide particles surface-modified by only the silane compound were in close contact with each other, in contrast to which the metal oxide particles surface-modified by the silane compound and the silicone compound sometimes had gaps observed between the metal oxide particles and the metal oxide particles. That is, it is presumed that the silicone chain of the silicone compound becomes a steric hindrance, and loosens the close contact of the particles with each other. Therefore, the metal oxide particles surface-modified by the silane compound and the silicone compound inhibit the aggregation of the particles with each other. As a result, it is presumed that, even in the case of being mixed with a silicone resin for an LED, the viscosity of the composition is inhibited from increasing because the particles are not easily aggregated with each other. Furthermore, because the particles are not excessively in close contact with each other, the light emitted from the light emitting element is easily transmitted, and as a result, it is presumed that this contributes to the improvement in the brightness of the LED.

[0068] In the present embodiment, the molar ratio of the above-described methyl group to the above-described hydrocarbon group (methyl / hydrocarbon group) in the metal oxide particles is 0.01 or more and 10 or less, preferably 0.03 or more and 8 or less, more preferably 0.05 or more and 5 or less, and further preferably 0.1 or more and 3 or less. The molar ratio can be 0.2 to 0.8, 0.8 to 2, 2 to 6, 6 to 9, or the like, as needed.

[0069] By the above-mentioned molar ratio of 0.01 or more and 10 or less, the metal oxide particles can be transparently dispersed in both the methyl-based silicone resin and the phenyl-based silicone resin. In the case where the above-mentioned molar ratio is less than 0.01, methyl is too little to be dispersed in the methyl-based silicone resin. On the other hand, if the above-mentioned molar ratio exceeds 10, it cannot be dispersed in the phenyl-based silicone resin.

[0070] The above-mentioned molar ratio in the metal oxide particles refers to the ratio measured by the following method using NMR (nuclear magnetic resonance spectroscopy). That is, it refers to the molar ratio of the methyl contained in the metal oxide particles subjected to surface modification to the hydrocarbon group having 2 or more carbon atoms. Therefore, it substantially refers to the molar ratio of the methyl contained in the silane compound and the silicone compound to the hydrocarbon group having 2 or more carbon atoms.

[0071] The dispersion liquid 15 g in which the solid content is adjusted to 30 mass% and methanol 15 g are mixed to precipitate the surface-modified metal oxide particles. The mixture is subjected to solid-liquid separation using a centrifugal separator, and the solid fraction (surface-modified metal oxide particles) is recovered. Several milligrams of the recovered surface-modified metal oxide particles are collected and dissolved in chloroform to be 1 mass%. Using this solution, and using an NMR device such as a benchtop NMR device (Nanalysis Scientific Corp., Model NMReady60 Pro (Nanalysis Scientific Corp.)), the liquid NMR spectrum of the hydrocarbon group having 2 or more carbon atoms and the methyl is measured. 1 H / 19 F) 1 H-liquid NMR spectrum. From the obtained spectrum, the spectral area (integral value) of the hydrocarbon group having 2 or more carbon atoms and the methyl is calculated, and the integral value of the methyl / the integral value of the hydrocarbon group having 2 or more carbon atoms is calculated. Thus, the molar ratio of the methyl to the hydrocarbon group having 2 or more carbon atoms can be calculated.

[0072] In addition, the solid content of the dispersion liquid need not be 30 mass%, as long as the amount required for measurement using NMR can be collected.

[0073] In the case where the silicone compound does not contain the methyl and the hydrocarbon group having 2 or more carbon atoms, only the molar ratio of the methyl contained in the silane compound to the hydrocarbon group having 2 or more carbon atoms needs to be adjusted. In the case where the silicone compound contains the methyl or the hydrocarbon group having 2 or more carbon atoms, only the molar ratio of the total of the methyl and the hydrocarbon group having 2 or more carbon atoms contained in the silane compound and the silicone compound needs to be adjusted to the prescribed range.

[0074] (2.1 Metal oxide particles)

[0075] The metal oxide particles scatter light emitted from the light emitting element in the sealing member described later. Also, the metal oxide particles increase the refractive index of the sealing member depending on the kind thereof. Thus, the metal oxide particles contribute to the increase in brightness of light in the light emitting device.

[0076] As the metal oxide particles, there is no particular limitation. In the present embodiment, as the metal oxide particles, for example, it is preferable to use metal oxide particles containing at least one kind selected from the group consisting of zirconium oxide particles, titanium oxide particles, zinc oxide particles, iron oxide particles, copper oxide particles, tin oxide particles, cerium oxide particles, tantalum oxide particles, niobium oxide particles, tungsten oxide particles, europium oxide particles, yttrium oxide particles, molybdenum oxide particles, indium oxide particles, antimony oxide particles, germanium oxide particles, zinc oxide particles, bismuth oxide particles, hafnium oxide particles, and potassium titanate particles, barium titanate particles, strontium titanate particles, potassium niobate particles, lithium niobate particles, calcium tungstate particles, yttrium oxide-stabilized zirconium oxide particles, aluminum oxide-stabilized zirconium oxide particles, calcium oxide-stabilized zirconium oxide particles, magnesium oxide-stabilized zirconium oxide particles, scandium oxide-stabilized zirconium oxide particles, hafnium oxide-stabilized zirconium oxide particles, ytterbium oxide-stabilized zirconium oxide particles, cerium oxide-stabilized zirconium oxide particles, indium oxide-stabilized zirconium oxide particles, strontium-stabilized zirconium oxide particles, samarium oxide-stabilized zirconium oxide particles, gadolinium oxide-stabilized zirconium oxide particles, antimony-added tin oxide particles, and indium-added tin oxide particles.

[0077] In the above, from the viewpoint of improving transparency or compatibility (affinity) with the sealing resin (resin component), the metal oxide particles are preferably at least one kind selected from the group consisting of zirconium oxide particles and titanium oxide particles.

[0078] Also, from the viewpoint of increasing the refractive index of the sealing member, the metal oxide particles preferably have a refractive index of 1.7 or more. The upper limit of the refractive index can be arbitrarily selected, and for example, can be 3.0 or less, 2.5 or less, but is not limited thereto.

[0079] The metal oxide particles are more preferably at least one of zirconium oxide particles and titanium oxide particles, and are particularly preferably zirconium oxide particles.

[0080] The average primary particle diameter of the metal oxide particles is preferably 1 nm or more and 200 nm or less, more preferably 3 nm or more and 150 nm or less, and further preferably 10 nm or more and 100 nm or less. If necessary, it can be 5 to 30 nm, 30 to 50 nm, 50 to 80 nm, 80 to 130 nm, or the like. By having the average primary particle diameter of the metal oxide particles within the above range, it is possible to suppress a decrease in transparency of the sealing member. As a result, it is possible to further increase the brightness of light in the light emitting device.

[0081] The average primary particle diameter of the metal oxide particles can be measured, for example, by observation with a transmission electron microscope. First, the inorganic oxide particles are observed with a transmission electron microscope to obtain a transmission electron microscope image. Next, inorganic oxide particles in a prescribed number, for example, 100, of the transmission electron microscope images are selected. Then, the longest linear amount (maximum major axis) of each of these inorganic oxide particles is measured, and the arithmetic mean of these measured values is calculated.

[0082] In this case, when the metal oxide particles are aggregated with each other, the aggregate particle diameter of the aggregate is not measured. The maximum major axis of the metal oxide particles that constitute the aggregate (primary particles) in a prescribed number is measured as the average primary particle diameter.

[0083] The average dispersed particle diameter of the metal oxide particles in the dispersion liquid of the present embodiment is not particularly limited, and is, for example, 10 nm or more and 300 nm or less, preferably 20 nm or more and 250 nm or less, and more preferably 30 nm or more and 200 nm or less. If necessary, it can be 50 nm or more and 180 nm or less, or 100 nm or more and 150 nm or less. By making the average dispersed particle diameter of the metal oxide particles 10 nm or more, the luminance of light of a light-emitting device to be described later, which is manufactured using the dispersion liquid, is improved. Also, by making the average dispersed particle diameter of the metal oxide particles 300 nm or less, the decrease in the light transmittance of the dispersion liquid or the composition or the sealing member to be described later, which is manufactured using the dispersion liquid, is suppressed. As a result, the luminance of light of the light-emitting device is improved.

[0084] In addition, the average dispersed particle diameter of the metal oxide particles can be the particle diameter D50 of the metal oxide particles at the time when the cumulative percentage of the scattering intensity distribution obtained by the dynamic light scattering method is 50%, and can be measured using a dynamic light scattering particle size distribution meter (for example, manufactured by HORIBA, Ltd., model number: SZ-100SP). The measurement can be performed using a quartz cell with an optical path length of 10 mm x 10 mm, with a dispersion liquid in which the solid content is adjusted to 5% by mass as the measurement target. In addition, in the present specification, the "solid content" refers to the residue when the volatile components are removed from the dispersion liquid. For example, when 1.2 g of the dispersion liquid is placed in a magnetic crucible and heated at 150°C for 1 hour using a hot plate, the components (metal oxide particles or surface modification materials, etc.) that do not volatilize and remain can be used as the solid content.

[0085] Further, regardless of which state of primary particles or secondary particles the metal oxide particles are dispersed in, the average dispersed particle diameter of the metal oxide particles is measured and calculated based on the diameters of the metal oxide particles in the dispersed state. Further, in the present embodiment, the average dispersed particle diameter of the metal oxide particles can also be measured as the average dispersed particle diameter of the metal oxide particles to which the surface modification material is attached. In the dispersion liquid, there can be metal oxide particles to which the surface modification material is attached and metal oxide particles to which the surface modification material is not attached. Therefore, generally, the average dispersed particle diameter of the metal oxide particles is measured as a value in their mixed state.

[0086] The surface modification material described below is attached to the surface of the metal oxide particles described above. Thereby, the metal oxide particles are stably dispersed in the dispersion liquid and the composition produced using the metal oxide particles.

[0087] (2.2 Silane compound)

[0088] The surface-modified metal oxide particles according to the present embodiment are metal oxide particles that are surface-modified with at least one silane compound and at least one silicone compound. The at least one silane compound contains a methyl group and a hydrocarbon group having 2 or more carbon atoms and is sufficiently attached to the metal oxide particles.

[0089] As the silane compound in the present embodiment, for example, a silane compound containing a methyl group and a hydrocarbon group having 2 or more carbon atoms can be used, or a silane compound containing a methyl group, i.e., a silane compound containing a methyl group but not containing a hydrocarbon group having 2 or more carbon atoms, can be used in combination with a silane compound containing a hydrocarbon group having 2 or more carbon atoms. In the present embodiment, it is preferable to use a silane compound containing at least a methyl group. As examples of the combination, for example, a silane compound containing a methyl group and a silane compound containing a hydrocarbon group having 2 or more carbon atoms can be used simultaneously, or a silane compound containing a methyl group and a hydrocarbon group having 2 or more carbon atoms and a silane compound containing a methyl group can be used simultaneously, or a methyl group and a hydrocarbon group having 2 or more carbon atoms and a silane compound containing a hydrocarbon group having 2 or more carbon atoms can be used simultaneously, or a silane compound containing a methyl group and a hydrocarbon group having 2 or more carbon atoms and a silane compound containing a hydrocarbon group having 2 or more carbon atoms can be used simultaneously, or a silane compound containing a methyl group and a silane compound containing a hydrocarbon group having 2 or more carbon atoms can be used simultaneously. The number (kind) of the silane compound used in the present embodiment is not particularly limited, and for example, it can be 1 to 10 kinds, 2 to 8 kinds, 3 to 6 kinds, 4 to 5 kinds, or the like.

[0090] From the viewpoint of making more silane compounds adhere to the metal oxide particles, the surface of the metal oxide particles must be modified with a silane compound containing a methyl group. Also, the secondary modification is performed in order to improve the compatibility with the silicone resin, and therefore there is no particular limitation as long as it is a silane compound having a functional group that is compatible with the functional group of the silicone resin. The silicone resin for an LED typically contains a methyl group and a phenyl group as hydrocarbon groups as the functional groups. Therefore, the silane compound in the present embodiment is modified once with a silane compound containing a methyl group, and modified twice with a silane compound containing a hydrocarbon group having a carbon number of 2 or more and having a higher hydrophobicity than a methyl group.

[0091] At least a part of these silane compounds adhere to the surface of the metal oxide particles, and by modifying the surface, the aggregation of the metal oxide particles is prevented. Also, the compatibility with the silicone resin component for an LED, in other words, the compatibility with the silicone resin component containing a methyl group and a phenyl group is improved.

[0092] Here, the "adhesion" of the silane compound to the metal oxide particles means that the silane compound is in contact with or bonded to the metal oxide particles through an interaction or a reaction therebetween. As the contact, for example, physical adsorption can be given. Also, as the bonding, for example, ionic bonding, hydrogen bonding, covalent bonding, and the like can be given.

[0093] As the silane compound containing a methyl group, there is no particular limitation as long as it is a compound that can adhere to the surface of the metal oxide particles. As the silane compound containing a methyl group, a silane compound containing a methyl group and an alkoxy group, a silane compound containing a methyl group and an H-Si group, and a silane compound containing a methyl group, an alkoxy group, and an H-Si group can be used.

[0094] The silane compound containing a methyl group can be used alone or in combination with two or more. As the silane compound containing a methyl group, a silane compound containing an alkoxy group, and particularly a silane compound containing a methoxy group is easily adhered to the metal oxide particles, and therefore is preferred.

[0095] As the silane compound containing a methyl group and an alkoxy group, for example, at least one selected from the group of methyltrimethoxysilane, methyltriethoxysilane, methyltripropoxysilane, methylphenyldimethoxysilane, methylphenyldiethoxysilane, trimethylmethoxysilane, trimethylethoxysilane, methoxydimethyl(phenyl)silane, ethoxydimethyl(phenyl)silane, dimethyl(methoxy)phenylsilane, and dimethyl(ethoxy)phenylsilane can be used.

[0096] As the silane compound containing a methyl group and an H-Si group, at least one selected from the group of dimethylchlorosilane, methyldichlorosilane, and methylphenylchlorosilane can be used.

[0097] As the silane compound containing a methyl group, an alkoxy group, and an H-Si group, for example, diethoxymethylsilane or ethoxydimethylsilane can be used.

[0098] From the viewpoint that the viscosity of the silane compound containing a methyl group is low and the dispersion of the metal oxide particles in the dispersion step described later becomes easy, the silane compound containing a methyl group and an alkoxy group is preferably contained.

[0099] The number of the alkoxy groups in the silane compound containing a methyl group and an alkoxy group is preferably 1 or more and 3 or less, and more preferably 3. The number of carbon atoms of the alkoxy group is preferably 1 or more and 5 or less, and also preferably 2 or more and 4 or less.

[0100] The number of the methyl groups in the silane compound containing a methyl group and an alkoxy group is preferably 1 or more and 3 or less, and more preferably 1.

[0101] The total number of the alkoxy groups and the methyl groups in the silane compound containing a methyl group and an alkoxy group is 2 or more and 4 or less, and is preferably 4.

[0102] The silane compound containing a methyl group contains, for example, at least one selected from the group consisting of methyltrimethoxysilane, methyltriethoxysilane, and methyltripropoxysilane. From the viewpoint that it is easy to adhere to the surface of the metal oxide particles, methyltrimethoxysilane is preferable, methyltriethoxysilane is more preferable, and methyltrimethoxysilane is further preferable.

[0103] As the hydrocarbon group having 2 or more carbon atoms contained in the silane compound, there is no particular limitation as long as it is a group that is compatible with the silicone resin for LED. For example, it can be an aliphatic hydrocarbon group having 2 or more carbon atoms, or it can be an aromatic hydrocarbon group.

[0104] The number of carbon atoms of the hydrocarbon group can be appropriately selected depending on the kind of the functional group contained in the silicone resin for LED. In view of the fact that the silicone resin for LED usually contains a methyl group and a phenyl group, the number of carbon atoms is preferably 2 or more and 20 or less, more preferably 3 or more and 16 or less, further preferably 4 or more and 12 or less, and more further preferably 5 or more and 9 or less.

[0105] As the aliphatic hydrocarbon group, an alkyl group, an alkenyl group, or an alkynyl group can be used. It can be a chain aliphatic hydrocarbon group, or it can be a cyclic aliphatic hydrocarbon group. As the alkyl group, for example, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, or the like can be used. As the alkenyl group, for example, a vinyl group, an allyl group, a propenyl group, a butenyl group, or the like can be used. As the alkynyl group, an ethynyl group, a propynyl group, a butynyl group, or the like can be used.

[0106] As the aromatic hydrocarbon group, an aryl group or an aralkyl group can be used.

[0107] As the aryl group, for example, a phenyl group, a tolyl group, a xylyl group, a biphenyl group, a 1-naphthyl group, a 2-naphthyl group, a phenanthryl group, or the like can be used.

[0108] As the aralkyl group, for example, a triphenylmethyl group, a benzyl group, a phenethyl group, a phenylpropyl group, a phenylvinyl group, a benzylidene group, or the like can be used.

[0109] Of the above, from the viewpoint of excellent compatibility with the silicone resin for an LED, as the hydrocarbon group having 2 or more carbon atoms, a phenyl group or a xylyl group is preferable, and a phenyl group is more preferable.

[0110] As the silane compound containing a hydrocarbon group having 2 or more carbon atoms, for example, at least one selected from the group of phenyltrimethoxysilane, phenyltriethoxysilane, methylphenylchlorosilane, diphenylchlorosilane, phenyldichlorosilane, methylphenyldimethoxysilane, diphenylmonomethoxysilane, methylphenyldiethoxysilane, and diphenylmonoethoxysilane can be used. Of these, from the viewpoint of easy adjustment of the improvement in compatibility with the silicone resin for an LED, it is preferable to use phenyltrimethoxysilane.

[0111] The content of the silane compound in the dispersion liquid is not particularly limited, and, for example, it is preferably 100% by mass or more and 700% by mass or less, more preferably 150% by mass or more and 600% by mass or less, and further preferably 190% by mass or more and 500% by mass or less, with respect to the amount of the metal oxide particles. If necessary, it can be 200 to 450% by mass, 250 to 400% by mass, or the like. Thereby, the silane compound can be densely attached to the surface of the metal oxide particles, and it is possible to improve the dispersion stability of the metal oxide particles while improving the dispersibility in the methyl-based silicone resin and the phenyl-based silicone resin.

[0112] The surface-modified metal oxide particles according to the present embodiment can contain a silane compound other than the silane compound containing a methyl group or the silane compound containing a hydrocarbon group having 2 or more carbon atoms, or a surface modification material generally used in the surface modification of metal oxide particles, as long as the purpose of the present application is not hindered.

[0113] (2.3 Silicone compound)

[0114] The silicone compound has a relatively large molecular weight, and is useful in improving the affinity with the silicone resin component described later. The silicone compound is present in the vicinity of the surface of the metal oxide particle surface-modified with the silane compound. The silicone compound functions as a medium between the metal oxide particle surface-modified with the silane compound and the silicone resin component described later. Therefore, the silicone compound is not particularly limited as long as it is a substance that is compatible with the metal oxide particle surface-modified with the silane compound and the silicone resin component. The number (kind) of the silicone compound used in the present embodiment is not particularly limited, and can be, for example, 1 to 10, 2 to 8, 3 to 6, 4 to 5, or the like.

[0115] The silicone compound can be present between the metal oxide particle surface-modified with the silane compound and the silicone resin component, and therefore can be present in the vicinity of the surface of the metal oxide particle surface-modified with the silane compound. The silicone compound can be attached to the metal oxide particle surface-modified with the silane compound, or can not be attached to the metal oxide particle surface-modified with the silane compound.

[0116] That is, the "surface-modified with a silane compound and a silicone compound" in the present embodiment means a state in which the silane compound is attached to the metal oxide particle, and the silicone compound is present in the vicinity of the surface of the metal oxide particle to which the silane compound is attached.

[0117] The silicone compound of the present embodiment and the silicone resin for an LED both contain a methyl group and a hydrocarbon group having 2 or more carbon atoms, and therefore the silicone compound of the present embodiment preferably contains a methyl group, a hydrocarbon group having 2 or more carbon atoms, or both a methyl group and a hydrocarbon group having 2 or more carbon atoms. The same groups as those of the silane compound described above can be used for the hydrocarbon group having 2 or more carbon atoms. In addition, the silicone compound used in the present embodiment is not limited to the above-described compound, and can contain or not contain a methyl group, and can contain or not contain a hydrocarbon group having 2 or more carbon atoms.

[0118] As the silicone compound, for example, an alkoxyl group-containing phenyl silicone, a dimethyl silicone, a methyl phenyl silicone, a methyl hydrogen silicone, a methyl phenyl hydrogen silicone, a diphenyl hydrogen silicone, an alkoxyl group-both-terminal phenyl silicone, an alkoxyl group-both-terminal methyl phenyl silicone, an alkoxyl group-containing methyl phenyl silicone, an alkoxyl group-containing dimethyl silicone, an alkoxyl group-one-terminal trimethyl one-terminal (methyl one-terminal) dimethyl silicone, an alkoxyl group-containing phenyl silicone, or the like can be given. These silicone compounds can be used alone or in combination with two or more.

[0119] The silicone compound can be a monomer, an oligomer, or a resin (polymer). Since surface modification is easy, a monomer or an oligomer is preferably used.

[0120] From the viewpoints of easiness of the reaction and the degree of hydrophobicity, the silicone compound preferably contains at least one selected from the group consisting of an alkoxyl group-containing phenyl silicone, a dimethyl silicone, a methyl phenyl silicone, an alkoxyl group-terminated phenyl silicone, an alkoxyl group-terminated methyl phenyl silicone, an alkoxyl group-containing methyl phenyl silicone, an alkoxyl group-containing dimethyl silicone, an alkoxyl group-monoterminated trimethyl monoterminated (methyl monoterminated) dimethyl silicone, and an alkoxyl group-containing phenyl silicone, more preferably at least one selected from the group consisting of a methoxyl group-containing phenyl silicone, a dimethyl silicone, and a methoxyl group-containing dimethyl silicone.

[0121] The content of the silicone compound in the dispersion liquid is not particularly limited, and is preferably 10% by mass or more and 500% by mass or less, more preferably 15% by mass or more and 400% by mass or less, and further preferably 100% by mass or more and 300% by mass or less, with respect to the metal oxide particles. If necessary, it can also be 20% by mass or more and 250% by mass or less, 30% by mass or more and 200% by mass or less, or 50% by mass or more and 100% by mass or less. Thereby, a sufficient amount of the silicone compound can be attached to the surface of the metal oxide particles, and the dispersion stability of the metal oxide particles can be improved, and the dispersibility in the methyl-based silicone resin can be improved. Furthermore, the amount of free silicone compound can be reduced, and unintended aggregation of the metal oxide particles in the methyl-based silicone resin and the phenyl-based silicone resin can be suppressed.

[0122] Furthermore, the dispersion liquid can contain, as the surface modification material, a general surface modification material or dispersant other than the above-described silane compound and the above-described silicone compound.

[0123] The total content of the silane compound and the silicone compound with respect to the amount of the metal oxide particles is not particularly limited, and is preferably 100% by mass or more and 1000% by mass or less, more preferably 150% by mass or more and 800% by mass or less, and further preferably 190% by mass or more and 600% by mass or less. If necessary, it can also be 250% by mass or more and 500% by mass or less, 300% by mass or more and 400% by mass or less, or the like. If the total amount of the silane compound and the silicone compound is within the above-described range, the amount of free silane compound or silicone compound can be reduced, and the dispersibility of the metal oxide particles can be sufficiently improved.

[0124] (2.4 Solvent)

[0125] The dispersion liquid according to the present embodiment contains a solvent for dispersing the metal oxide particles as a dispersion medium. The solvent is not particularly limited as long as it can disperse the metal oxide particles which are surface-modified with the silane compound and the silicone compound, and can be mixed with the silicone resin component described later, and is preferably a hydrophobic solvent.

[0126] As such a hydrophobic solvent, for example, aromatic compounds, saturated hydrocarbons, unsaturated hydrocarbons, and the like can be given. These hydrophobic solvents can be used alone or in combination of two or more.

[0127] Among the above, the hydrophobic solvent is preferably an aromatic compound, and particularly preferably an aromatic hydrocarbon. The aromatic compound has excellent compatibility with the silicone resin for LED, and is useful in improving the viscosity properties of the composition obtained thereby and improving the quality (transparency, shape, and the like) of the sealing member formed.

[0128] As such an aromatic hydrocarbon, for example, benzene, toluene, ethylbenzene, 1-phenylpropane, cumene, n-butylbenzene, t-butylbenzene, sec-butylbenzene, o-xylene, m-xylene, p-xylene, 2-ethyltoluene, 3-ethyltoluene, or 4-ethyltoluene, and the like can be given. These aromatic hydrocarbons can be used alone or in combination of two or more.

[0129] Among the above, from the viewpoint of the stability of the dispersion liquid, the ease of operability in the removal of the hydrophobic solvent at the time of manufacturing the composition described later, and the like, the hydrophobic solvent is preferably at least one selected from the group consisting of toluene, o-xylene, m-xylene, p-xylene, and benzene, and more preferably toluene.

[0130] The content of the solvent contained in the dispersion liquid is appropriately adjusted to the desired solid content. The content of the solvent is, for example, preferably 40% by mass or more and 95% by mass or less, more preferably 50% by mass or more and 90% by mass or less, and further preferably 60% by mass or more and 80% by mass or less. Thereby, the mixing of the dispersion liquid with the resin component described later, particularly the silicone resin for LED, becomes easier.

[0131] The dispersion liquid of the present embodiment can contain a hydrophilic solvent. The hydrophilic solvent can be contained in the dispersion liquid, for example, due to the method described later. As such a hydrophilic solvent, for example, alcohol-based solvents, ketone-based solvents, nitrile-based solvents, and the like can be given. These hydrophilic solvents can be used alone or in combination of two or more.

[0132] As the alcohol-based solvent, for example, a branched or straight-chain alcohol compound having 1 to 4 carbon atoms and an ether condensate thereof can be mentioned. These alcohol-based solvents can be used alone or in combination of two or more. Also, the alcohol compound contained in the alcohol-based solvent can be any one of a primary alcohol, a secondary alcohol, and a tertiary alcohol. Also, the alcohol compound contained in the alcohol-based solvent can be any one of a monohydric alcohol, a dihydric alcohol, and a trihydric alcohol. More specifically, as the alcohol-based solvent, for example, methanol, ethanol, 1-propanol, isopropanol, 1-butanol, 2-butanol, isobutyl alcohol, t-butyl alcohol, methyl glycol, 1,2-ethanediol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 2-buten-1,4-diol, 1,4-butynediol, glycerol, diethylene glycol, 3-methoxy-1,2-propanediol, and the like can be mentioned.

[0133] As the ketone-based solvent, for example, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, and the like can be mentioned.

[0134] As the nitrile-based solvent, for example, acetonitrile and the like can be mentioned.

[0135] From the viewpoint of excellent affinity with both water and the hydrophobic solvent, and promoting the mixing thereof, the hydrophilic solvent preferably contains an alcohol-based solvent. In this case, the number of carbon atoms of the alcohol compound constituting the alcohol-based solvent is preferably 1 or more and 3 or less, more preferably 1 or more and 2 or less.

[0136] Among the above, methanol and ethanol, and particularly methanol can sufficiently exhibit the effects of the above-described alcohol-based solvent, and thus can be preferably used.

[0137] Also, the content of the hydrophilic solvent in the dispersion liquid is, for example, preferably 10% by mass or less, more preferably 7% by mass or less, further preferably 5% by mass or less, and particularly preferably 3% by mass or less. It can be 1% by mass or less, 0.5% by mass or less, or 0.1% by mass or less. The content of the hydrophilic solvent can also be 0% by mass.

[0138] (2.5 Other Components)

[0139] The dispersion liquid according to the present embodiment can also contain components other than the above. For example, the dispersion liquid according to the present embodiment can contain, as needed, components other than the above, such as a dispersant, a dispersion aid, an antioxidant, a flow adjusting agent, a thickening agent, a pH adjusting agent, a preservative, and the like.

[0140] Also, the dispersion liquid according to the present embodiment can contain components obtainable by the methods described later, such as an acid, water, an alcohol, and the like.

[0141] Further, in the present specification, the dispersion liquid according to the present embodiment is distinguished from the composition according to the present embodiment, and the composition according to the present embodiment contains a resin component and is capable of forming a sealing member by curing. That is, the dispersion liquid according to the present embodiment does not contain the resin component described later to the extent that it is capable of forming a sealing member even by simple curing. More specifically, the mass ratio of the resin component to the metal oxide particles in the dispersion liquid according to the present embodiment is preferably in the range of 0: 100 to 40: 60, and more preferably in the range of 0: 100 to 20: 80, in terms of resin component: inorganic oxide particles. If necessary, it can be in the range of 0: 100 to 10: 90, in the range of 0: 100 to 5: 95, or in the range of 0: 100 to 2: 98. The dispersion liquid according to the present embodiment is further preferably substantially free of the resin component described later, and is particularly preferably completely free of the resin component described later.

[0142] The dispersion liquid according to the present embodiment contains a prescribed silane compound and metal oxide particles surface-modified with a silicone compound, and a solvent, and satisfies the above formula (1), and is thus capable of being dispersed in both methyl-based silicone resins and phenyl-based silicone resins. Therefore, in the case where the dispersion liquid according to the present embodiment is dispersed in a methyl-based silicone resin, or in the case where it is dispersed in a phenyl-based silicone resin, the generation of turbidity such as white turbidity is suppressed. Also, the viscosity change of a silicone resin for an LED containing surface-modified metal oxide particles is suppressed.

[0143] <3. Method for producing dispersion liquid>

[0144] Next, a method for producing the dispersion liquid according to the present embodiment will be described.

[0145] The method for producing the dispersion liquid according to the present embodiment includes a step B of mixing a first surface-modifying material and metal oxide particles to obtain a mixed liquid, a step C of dispersing the metal oxide particles in the mixed liquid, and a step F of adding a second surface-modifying material to the mixed liquid to obtain a dispersion liquid. The content of the metal oxide particles in the mixed liquid is 10 mass% or more and 49 mass% or less, and the total content of the first surface-modifying material and the metal oxide particles in the mixed liquid is 65 mass% or more and 98 mass% or less. The first surface-modifying material is a silane compound containing a methyl group, and the second surface-modifying material includes a silane compound containing a hydrocarbon group having 2 or more carbon atoms and a silicone compound.

[0146] The content of the metal oxide particles in the mixed solution can also be 15 mass% or more and 45 mass% or less, 20 mass% or more and 40 mass% or less, 25 mass% or more and 35 mass% or less, or 30 mass% or more and 33 mass% or less, as needed. The total content of the first surface modification material and the metal oxide particles in the mixed solution can also be 68 mass% or more and 97 mass% or less, 69 mass% or more and 96 mass% or less, 70 mass% or more and 95 mass% or less, 75 mass% or more and 90 mass% or less, or 80 mass% or more and 85 mass% or less, as needed.

[0147] That is, the method for producing a dispersion liquid according to the present embodiment includes: a step B of obtaining a mixed solution by mixing a silane compound containing a methyl group and metal oxide particles; a step C of obtaining a dispersion liquid (first dispersion liquid) by dispersing the metal oxide particles in the mixed solution; and a step F of obtaining a dispersion liquid (third dispersion liquid) by adding a silane compound containing a hydrocarbon group having 2 or more carbon atoms and a silicone compound to the dispersion liquid containing the metal oxide particles.

[0148] Also, the method for producing a dispersion liquid according to the present embodiment is also a method for surface-modifying metal oxide particles. Therefore, it can also be described as follows.

[0149] That is, the method for surface-modifying metal oxide particles according to the present embodiment includes: a step B of obtaining a mixed solution by mixing a first surface modification material and metal oxide particles; a step C of dispersing the metal oxide particles in the mixed solution; and a step F of adding a second surface modification material to the mixed solution. The content of the metal oxide particles in the mixed solution is 10 mass% or more and 49 mass% or less, and the total content of the first surface modification material and the metal oxide particles in the mixed solution is 65 mass% or more and 98 mass% or less. The first surface modification material is a silane compound containing a methyl group, and the second surface modification material includes a silane compound containing a hydrocarbon group having 2 or more carbon atoms and a silicone compound.

[0150] In addition, the total content of the silane compound containing a methyl group, the silane compound containing a hydrocarbon group having 2 or more carbon atoms, and the metal oxide particles can also be evaluated by the solid content. Also, the total content of the silane compound containing a methyl group, the silane compound containing a hydrocarbon group having 2 or more carbon atoms, the silicone compound, and the metal oxide particles can also be evaluated by the solid content.

[0151] Also, the total content of the above-mentioned silane compound containing a methyl group and the above-mentioned silane compound containing a hydrocarbon group having 2 or more carbon atoms and the above-mentioned metal oxide particles does not include alcohol produced in the hydrolysis of the above-mentioned silane compound. That is, the total content of the above-mentioned silane compound containing a methyl group and the above-mentioned silane compound containing a hydrocarbon group having 2 or more carbon atoms and the above-mentioned metal oxide particles means the total content of the silane compound, the silane compound after the hydrolysis, and the metal oxide particles. Also, the above-mentioned total content naturally includes the content of the above-mentioned silane compound containing a methyl group, the above-mentioned silane compound containing a hydrocarbon group having 2 or more carbon atoms, and the metal oxide particles attached to the silicone compound.

[0152] Also, in the present embodiment, before the above-mentioned process B, as needed, a process A (hydrolysis process) in which a silane compound containing a methyl group or a silane compound containing a hydrocarbon group having 2 or more carbon atoms and water are mixed to obtain a hydrolysis solution containing a hydrolyzed silane compound containing a methyl group or a hydrolysis solution containing a hydrolyzed silane compound containing a hydrocarbon group having 2 or more carbon atoms can be provided.

[0153] Hereinafter, each process will be described in detail. Also, the process of hydrolyzing the silane compound containing a methyl group will be described as a first hydrolysis process, and the process of hydrolyzing the silane compound containing a hydrocarbon group having 2 or more carbon atoms will be described as a second hydrolysis process.

[0154] (Process A (first hydrolysis process))

[0155] In the first hydrolysis process, a silane compound containing a methyl group (first silane compound) and water are mixed to obtain a hydrolysis solution containing a hydrolyzed silane compound containing a methyl group. Thus, by using a mixed solution in which at least a part of the silane compound containing a methyl group is preliminarily hydrolyzed, the silane compound containing a methyl group easily adheres to the metal oxide particles in the dispersion process C described later. The silane compound containing a methyl group does not contain a hydrocarbon group having 2 or more carbon atoms.

[0156] The content of the silane compound containing a methyl group in the hydrolysis solution is not particularly limited and can be the remaining portion of other components in the hydrolysis solution, and for example, is preferably 60% by mass or more and 99% by mass or less, more preferably 70% by mass or more and 97% by mass or less, and further preferably 80% by mass or more and 95% by mass or less.

[0157] Also, in the first hydrolysis process, the hydrolysis solution can contain a surface modification material other than the silane compound containing a methyl group.

[0158] In the first hydrolysis process, the hydrolysis solution includes water. The water becomes a substrate of the hydrolysis reaction of the surface modification material such as the silane compound containing a methyl group.

[0159] The content of water in the hydrolysis solution is not particularly limited, and can be appropriately set, for example, in correspondence with the amount of the methyl group-containing silane compound. For example, the amount of water added to the hydrolysis solution is preferably 0.5 mol or more and 5 mol or less, more preferably 0.6 mol or more and 3 mol or less, and further preferably 0.7 mol or more and 2 mol or less, relative to 1 mol of the methyl group-containing silane compound. Thus, the hydrolysis reaction of the methyl group-containing silane compound can be sufficiently performed, and the aggregation of the inorganic oxide particles in the dispersion liquid produced by an excess amount of water can be more reliably prevented.

[0160] Alternatively, the content of water in the hydrolysis solution is preferably, for example, 1% by mass or more and 20% by mass or less, more preferably 1% by mass or more and 15% by mass or less, and further preferably 1% by mass or more and 10% by mass or less. If necessary, it can be 2% by mass or more and 8% by mass or less, 3% by mass or more and 7% by mass or less, or 4% by mass or more and 6% by mass or less.

[0161] Further, a catalyst can be added to the hydrolysis solution together with the methyl group-containing silane compound and water. As the catalyst, for example, an acid or a base can be used.

[0162] The acid catalyzes the hydrolysis reaction of the methyl group-containing silane compound in the hydrolysis solution. On the other hand, the base catalyzes the condensation reaction of the methyl group-containing silane compound after the hydrolysis with the functional group on the surface of the metal oxide particles, for example, with the hydroxyl group or the silanol group. Thus, in the dispersion step (Step C) described later, the methyl group-containing silane compound is easily attached to the metal oxide particles, and the dispersion stability of the metal oxide particles is improved.

[0163] Here, the above-mentioned "acid" refers to an acid based on the so-called Bronsted-Lowry definition, and refers to a substance that donates a proton in the hydrolysis reaction of the surface modification material such as the methyl group-containing silane compound. Further, the above-mentioned "base" refers to a base based on the so-called Bronsted-Lowry definition, and refers to a substance that accepts a proton in the hydrolysis reaction and the subsequent condensation reaction of the methyl group-containing silane compound and the like.

[0164] As the acid, there is no particular limitation as long as it can supply a proton in the hydrolysis reaction of the methyl group-containing silane compound, and for example, inorganic acids such as hydrochloric acid, hydrobromic acid, hydroiodic acid, sulfuric acid, nitric acid, boric acid, and phosphoric acid, or organic acids such as acetic acid and citric acid, and formic acid can be given. These organic acids can be used alone as one kind, or two or more kinds in combination.

[0165] As the base, there is no particular limitation as long as it can accept a proton in the hydrolysis reaction of the silane compound containing a methyl group, and for example, sodium hydroxide, potassium hydroxide, barium hydroxide, calcium hydroxide, ammonia, amine, and the like can be given. These bases can be used alone or in combination with two or more.

[0166] Among the above, as the catalyst, an acid is preferably used. From the viewpoint of acidity, an inorganic acid is preferable, and hydrochloric acid is more preferable.

[0167] The content of the catalyst in the hydrolysis solution is not particularly limited, and for example, it is preferably 10 ppm or more and 1000 ppm or less, more preferably 20 ppm or more and 800 ppm or less, and further preferably 30 ppm or more and 600 ppm or less. Thereby, the hydrolysis of the silane compound containing a methyl group can be sufficiently promoted, and the side reaction of the silane compound containing a methyl group can be suppressed.

[0168] Further, the hydrolysis solution can contain a hydrophilic solvent. The hydrophilic solvent promotes the mixing of water and the silane compound in the hydrolysis solution, and further promotes the hydrolysis reaction of these silane compounds.

[0169] As such a hydrophilic solvent, for example, various hydrophilic solvents that can be contained in the dispersion liquid described later can be given.

[0170] Among the above, from the viewpoint that the affinity with both water and the hydrophobic solvent is excellent and the mixing thereof is promoted, the hydrophilic solvent preferably contains at least one selected from the group consisting of alcohol-based solvents, and more preferably contains at least one of methanol and ethanol.

[0171] Further, the content of the hydrophilic solvent in the hydrolysis solution is not particularly limited, and for example, it is preferably 60% by mass or less, and more preferably 50% by mass or less. Thereby, the content of the silane compound and water in the hydrolysis solution can be sufficiently increased. Further, the content of the hydrophilic solvent in the hydrolysis solution is, for example, preferably 10% by mass or more, and more preferably 15% by mass or more. Thereby, the mixing of the silane compound containing a methyl group and water can be further promoted, and as a result, the hydrolysis reaction of the silane compound containing a methyl group can be efficiently performed. In addition, in the hydrolysis solution, the hydrophilic solvent other than the compound derived from the hydrolysis reaction can not be contained.

[0172] In the hydrolysis step, after the hydrolysis solution is prepared, it can be kept at a constant temperature for a prescribed time. Thereby, the hydrolysis of the silane compound can be further promoted.

[0173] In this treatment, the temperature of the hydrolysis solution is not particularly limited, and can be appropriately changed depending on the kind of the silane compound, and for example, it is preferably 5°C or more and 65°C or less, and more preferably 30°C or more and 60°C or less.

[0174] Further, the holding time is not particularly limited, and for example, it is preferably 10 minutes or more and 180 minutes or less, and more preferably 30 minutes or more and 120 minutes or less.

[0175] Further, in the holding of the above hydrolysis solution, the hydrolysis solution can be appropriately stirred.

[0176] (Step A (2nd hydrolysis step))

[0177] In the 2nd hydrolysis step, a silane compound containing a hydrocarbon group having 2 or more carbon atoms (2nd silane compound) and water are mixed to obtain a hydrolysis solution containing a hydrolyzed silane compound containing a hydrocarbon group having 2 or more carbon atoms. In this way, by using a mixed solution in which at least a part of the silane compound containing a hydrocarbon group having 2 or more carbon atoms is hydrolyzed in advance, in the addition step F described later, the silane compound containing a hydrocarbon group having 2 or more carbon atoms is easily attached to the metal oxide particles. The silane compound containing a hydrocarbon group having 2 or more carbon atoms can have a methyl group or can not have a methyl group.

[0178] In the 2nd hydrolysis step, the silane compound containing a methyl group in the 1st hydrolysis step can be replaced with a silane compound containing a hydrocarbon group having 2 or more carbon atoms, and the same is performed.

[0179] (Step B (mixing step): primary modification)

[0180] In the mixing step, a silane compound containing a methyl group (1st silane compound) and metal oxide particles are mixed to obtain a mixed solution. The silane compound containing a methyl group can be a compound treated in the 1st hydrolysis step. In the mixing step, in addition to the silane compound containing a methyl group and the metal oxide particles, water or a catalyst can be mixed. Further, in the case where the hydrolysis solution is obtained by the above 1st hydrolysis step, by mixing the hydrolysis solution and the metal oxide particles, a mixed solution can be obtained.

[0181] Further, the mixing is performed in such a manner that the content of the metal oxide particles in the mixed solution is 10% by mass or more and 49% by mass or less, and the total content of the silane compound containing a methyl group and the inorganic oxide particles is 65% by mass or more and 98% by mass or less.

[0182] Thus, in the present embodiment, the total content of the silane compound containing a methyl group and the metal oxide particles in the mixed solution is very large. Also, the dispersion medium, such as an organic solvent and water, which has been considered necessary in the past is not included in the mixed solution, or only a very small amount is mixed. Or, by hydrolysis, the content of the unavoidable alcohol compound is only a small amount. Even in this case, by passing through the dispersion process, the metal oxide particles can be uniformly dispersed in the mixed solution while achieving uniform attachment (surface modification) of the silane compound containing a methyl group to the metal oxide particles.

[0183] In detail, in the case where the metal oxide particles are generally surface-modified using a surface-modifying material such as a silane compound in a liquid phase, generally, a mixed solution is obtained by mixing not only the metal oxide particles and the surface-modifying material but also a dispersion medium, and the mixed solution is subjected to dispersion treatment using a disperser. However, the metal oxide particles surface-modified by this method cannot be sufficiently dispersed in a methyl-based silicone resin when mixed with the methyl-based silicone resin and agglomerate, and as a result, there is a problem in that turbidity such as whitening occurs in the methyl-based silicone resin. In this case, the added metal oxide particles cannot sufficiently exhibit the target performance.

[0184] On the other hand, the silane compound containing a methyl group used in the present application is a low molecule and has a relatively small viscosity. Also, by hydrolysis in the above hydrolysis process, the attachment to the metal oxide particles is good. Therefore, the silane compound containing a methyl group is extremely suitable for the dispersion of the metal oxide particles in a high concentration of the silane compound.

[0185] In the case where the total content of the silane compound containing a methyl group and the metal oxide particles is less than 65% by mass, the component other than the above 2 components, such as the dispersion medium, becomes too much. Therefore, in the dispersion process (process C) described later, there is a tendency that the silane compound containing a methyl group cannot sufficiently attach to the surface of the metal oxide particles. As a result, a large amount of hydroxyl groups remains on the surface of the metal oxide particles, and when the obtained dispersion liquid is mixed with a hydrophobic material, the metal oxide particles agglomerate and turbidity occurs in the hydrophobic material. The total content of the silane compound containing a methyl group and the metal oxide particles can be 65% by mass or more, preferably 70% by mass or more, and more preferably 75% by mass or more.

[0186] On the other hand, when the total content of the silane compound containing a methyl group and the metal oxide particles exceeds 98% by mass, the viscosity of the mixed solution becomes too high, and in the dispersion process (process C) described later, the silane compound containing a methyl group cannot sufficiently attach to the surface of the metal oxide particles. The total content of the silane compound containing a methyl group and the metal oxide particles can be 98% by mass or less, preferably 97% by mass or less, and more preferably 95% by mass or less.

[0187] Also, as described above, the content of the metal oxide particles in the mixed solution is 10 mass% or more and 49 mass% or less. Thereby, the amount of the silane compound containing a methyl group with respect to the metal oxide particles can be within an appropriate range, and the silane compound containing a methyl group can be uniformly attached to the surface of the metal oxide particles while the viscosity of the mixed solution can be inhibited from increasing.

[0188] In contrast, in a case where the content of the metal oxide particles in the mixed solution is less than 10 mass%, the amount of the silane compound containing a methyl group with respect to the metal oxide particles is excessive, and the silane compound containing a methyl group that is excessive in the obtained dispersion liquid induces aggregation of the metal oxide particles. The content of the metal oxide particles in the mixed solution is preferably 20 mass% or more, and more preferably 30 mass% or more.

[0189] Also, when the content of the metal oxide particles exceeds 49 mass%, the amount of the silane compound containing a methyl group with respect to the metal oxide particles is insufficient, and an insufficient amount of the silane compound containing a methyl group is not attached to the metal oxide particles. Also, the content of the metal oxide particles becomes excessive, and as a result, the viscosity of the mixed solution excessively increases, and the metal oxide particles cannot be sufficiently dispersed in the dispersion process (process C) described later. The content of the metal oxide particles in the mixed solution is preferably 45 mass% or less, and more preferably 40 mass% or less.

[0190] The content of the silane compound containing a methyl group with respect to the content of the metal oxide particles in the mixed solution is not particularly limited, and is, for example, preferably 100 mass% or more and 800 mass% or less, more preferably 140 mass% or more and 600 mass% or less, and further preferably 180 mass% or more and 400 mass% or less. As needed, it can be 200 mass% or more and 300 mass% or less. Thereby, the amount of the silane compound containing a methyl group with respect to the metal oxide particles can be within an appropriate range, and the silane compound containing a methyl group can be uniformly attached to the surface of the metal oxide particles.

[0191] Also, in the mixing process, an organic solvent can be further mixed in the mixed solution. By mixing the organic solvent in the mixed solution, the reactivity of the silane compound can be controlled, and the degree of attachment of the silane compound to the surface of the metal oxide particles can be controlled. Also, the viscosity of the mixed solution can be adjusted by the organic solvent.

[0192] As such an organic solvent, the hydrophobic solvent or the hydrophilic solvent described as the dispersion medium of the dispersion liquid according to the present embodiment described above can be given. These organic solvents can be used alone as one kind, or two or more kinds can be used in combination.

[0193] The content of the organic solvent in the mixed solution is not particularly limited as long as the content of the metal oxide particles and the silane compound containing a methyl group described above is satisfied. In addition, of course, the mixed solution can not contain an organic solvent.

[0194] (Step C (dispersion step))

[0195] In the dispersion step, the metal oxide particles are dispersed in the mixed solution obtained in the mixing step to obtain a first dispersion liquid in which the metal oxide particles are dispersed. In the present embodiment, the metal oxide particles are dispersed in the high-concentration silane compound containing a methyl group after hydrolysis. Therefore, in the obtained first dispersion liquid, a first dispersion liquid in which the silane compound containing a methyl group is relatively uniformly attached to the surface of the metal oxide particles and the metal oxide particles are relatively uniformly dispersed is obtained.

[0196] The dispersion of the metal oxide particles can be performed using a publicly known disperser. As the disperser, for example, a bead mill, a ball mill, a homogenizer, a disperser, a stirrer, or the like is preferably used.

[0197] Here, in the dispersion step, the metal oxide particles are dispersed in the mixed solution in such a manner that the particle diameter of the metal oxide particles in the dispersion liquid (dispersion particle diameter) is substantially uniform, and preferably, no excessive energy is imparted, but the minimum required energy is imparted.

[0198] Further, a solvent addition step D (first addition step) in which a hydrophobic solvent is added to the first dispersion liquid to obtain a second dispersion liquid can be provided after the dispersion step.

[0199] As the hydrophobic solvent, the hydrophobic solvent described above as the dispersion medium of the dispersion liquid to which the present embodiment is directed can be cited. These hydrophobic solvents can be used alone as one kind, or two or more kinds can be used in combination.

[0200] (Step D (first addition step))

[0201] In the first addition step, a hydrophobic solvent is added to the above-described first dispersion liquid to obtain a second dispersion liquid in which the solid content (concentration) is adjusted to be desired.

[0202] The solid content (concentration) of the first dispersion liquid obtained in the dispersion step C is high, and therefore, the viscosity is high, and the handleability is poor. However, in order to reduce the solid content, if a hydrophobic solvent is added to the obtained first dispersion liquid, the hydrophobicity of the particle surface is low, and therefore, the particles are aggregated, and a uniform dispersion liquid cannot be obtained.

[0203] Therefore, the present inventors and the like have further found that by heating the obtained first dispersion liquid and slowly adding a hydrophobic solvent, a dispersion liquid in which the solid content is low can be adjusted.

[0204] The mechanism is presumed as follows.

[0205] By heating the first dispersion liquid, the silane compound having a methyl group attached to the metal oxide particles is polymerized, and the hydrophobicity of the particle surface is improved. Even if the polymerization reaction proceeds excessively, the metal oxide particles will agglomerate. Therefore, by slowly adding a hydrophobic solvent to the first dispersion liquid in which the polymerization reaction is in progress, the excessive polymerization reaction can be suppressed, and the surface can be slowly hydrophobized. Thus, the hydrophobic solvent can be slowly mixed in the first dispersion liquid.

[0206] That is, by adding the hydrophobic solvent in an amount in which the metal oxide particles do not agglomerate, the polymerization reaction of the silane compound having a methyl group can be allowed to proceed to a degree in which it is compatible with the amount of the hydrophobic solvent added. Thus, a dispersion liquid adjusted to a desired solid content can be obtained.

[0207] As described above, the hydrophobic solvent can be slowly added to prevent the metal oxide particles from agglomerating. Therefore, the solvent can be added after the first dispersion liquid is heated, the first dispersion liquid can be heated after the hydrophobic solvent is added, or the heating of the first dispersion liquid and the addition of the hydrophobic solvent can be performed simultaneously.

[0208] That is, the first addition process can be a process d1 in which the hydrophobic solvent is added at a rate in which the above metal oxide particles do not agglomerate after the above first dispersion liquid is heated, a process d2 in which the hydrophobic solvent is added at a rate in which the above metal oxide particles do not agglomerate while the above first dispersion liquid is heated, or a process d3 in which the above first dispersion liquid is heated after the hydrophobic solvent is added at a rate in which the above metal oxide particles do not agglomerate.

[0209] The rate at which the metal oxide particles do not agglomerate is not particularly limited. For example, the hydrophobic solvent can be continuously added at a rate in which the solid content decreases in a range of 3% by mass or more and 20% by mass or less within 1 hour. The amount of the hydrophobic solvent added can be appropriately adjusted so that the amount of the hydrophobic solvent added is increased in the case where the heating temperature is high, and the amount of the hydrophobic solvent added is decreased in the case where the heating temperature is low.

[0210] For example, the hydrophobic solvent can be added in stages so that the solid content decreases in a range of 3% by mass or more and 20% by mass or less every 30 minutes, every 1 hour, or every 2 hours. The amount of the hydrophobic solvent added can be appropriately adjusted so that the amount of the hydrophobic solvent added at one time is increased in the case where the heating temperature is high, and the amount of the hydrophobic solvent added at one time is decreased in the case where the heating temperature is low.

[0211] The heating temperature is not particularly limited as long as it is a temperature at which the polymerization of the silane compound containing a methyl group is performed. The heating temperature is preferably, for example, 35°C or higher and 80°C or lower. By the heating temperature being 35°C or higher, the polymerization of the silane compound containing a methyl group is performed. On the other hand, by the heating temperature being 80°C or lower, the aggregation of the metal oxide particles caused by the rapid reaction of the silane compound containing a methyl group is suppressed.

[0212] The heating time is not particularly limited as long as it is appropriately implemented until the adjustment of the solid content ends. The heating time is preferably, for example, 4 hours or longer and 12 hours or shorter. By the heating time being 4 hours or longer, the polymerization of the silane compound containing a methyl group is performed, and the mixing with the solvent is performed. On the other hand, by the heating time being 12 hours or shorter, the aggregation of the metal oxide particles caused by the excessive progress of the polymerization of the silane compound containing a methyl group is suppressed.

[0213] From the viewpoint of the easiness of the operability in the removal of the dispersion medium at the time of the production of the composition and the like, the hydrophobic solvent preferably uses at least one selected from the group consisting of toluene, o-xylene, m-xylene, p-xylene, and benzene, and more preferably uses toluene.

[0214] The content of the hydrophobic solvent contained in the final second dispersion liquid is appropriately adjusted to be a desired solid content. The content of the hydrophobic solvent is preferably, for example, 40% by mass or more and 95% by mass or less, more preferably 50% by mass or more and 90% by mass or less, and further preferably 60% by mass or more and 80% by mass or less.

[0215] By the first adding step, the second dispersion liquid adjusted to be a desired solid content can be obtained. By using the second dispersion liquid, the operability of the dispersion liquid in the following steps is improved.

[0216] (Step E (removal step))

[0217] In the present embodiment, a step E of removing an alcohol produced by hydrolysis can be provided after the step D.

[0218] It is presumed that by providing the removal step, the production efficiency of the composition described below is improved.

[0219] The removal method is not particularly limited, and, for example, an evaporator can be used. The removal step can be performed until the alcohol is completely removed, or about 5% by mass can remain.

[0220] (Step F (second adding step): secondary modification, or secondary modification and tertiary modification)

[0221] In the 2nd addition step, a silane compound having a hydrocarbon group having 2 or more carbon atoms (2nd silane compound) and a silicone compound are added to the 2nd dispersion liquid, and a 3rd dispersion liquid is obtained. Also, in the case where a hydrolysis liquid of a silane compound having a hydrocarbon group having 2 or more carbon atoms is obtained by the above hydrolysis step (2nd hydrolysis step), the 2nd dispersion liquid, the hydrolysis liquid of the silane compound having a hydrocarbon group having 2 or more carbon atoms, and the silicone compound are mixed, and a 3rd dispersion liquid is obtained. As described above, by performing the dispersion step C, the silane compound having a methyl group is relatively uniformly attached to the surface of the metal oxide particles. Therefore, it is presumed that in the 3rd dispersion liquid, the silane compound and the silicone compound newly added in the 2nd addition step are relatively uniformly attached to the surface of the metal oxide particles, with the above-mentioned silane compound having a methyl group already attached therebetween.

[0222] In the 2nd addition step, the mixed liquid (3rd dispersion liquid) in which the prescribed silane compound and the silicone compound are mixed in the 2nd dispersion liquid can also be held at a prescribed temperature for a prescribed period of time. By doing so, the attachment of the silane compound and the silicone compound to the metal oxide particles can be further promoted.

[0223] Also, the silane compound and the silicone compound can be added simultaneously, or the silicone compound can be added after the silane compound is added, or the silane compound can be added after the silicone compound is added. From the viewpoint of achieving excellent dispersibility, it is preferable that the silicone compound be added after the silane compound is added.

[0224] In the 2nd addition step, the holding temperature is not particularly limited, and can be appropriately changed depending on the kind of the silane compound, and is preferably 40°C or higher and 150°C or lower, and more preferably 50°C or higher and 140°C or lower, for example.

[0225] The holding time is not particularly limited, and is preferably 1 hour or longer and 24 hours or shorter, and more preferably 2 hours or longer and 20 hours or shorter, for example. Also, during the above holding, the 2nd dispersion liquid can also be appropriately stirred.

[0226] Also, in the 2nd addition step, the surface modification can be performed one or a plurality of times using one or more of the above-mentioned silane compounds. For example, one or more different kinds of silane compounds can be used, or the surface modification can be performed a plurality of times using the same silane compound.

[0227] Also, in the 2nd addition step, the surface modification can be performed one or a plurality of times using one or more of the above-mentioned silicone compounds. For example, one or more different kinds of silicone compounds can be used, or the surface modification can be performed a plurality of times using the same silicone compound.

[0228] Also, in the 2nd addition step, after the prescribed temperature is maintained for the prescribed time, the above solvent can be added to adjust the solid content of the 3rd dispersion liquid. By adding the solvent to reduce the solid content of the dispersion liquid, mixing with the silicone resin component described later becomes easier.

[0229] The amount of the silane compound added in the 2nd addition step, including the amount of the methyl-containing silane compound mixed in the mixing step B, can be added, for example, so as to be 100 mass% or more and 700 mass% or less with respect to the amount of the metal oxide particles.

[0230] Also, the molar ratio of the methyl group with respect to the hydrocarbon group having 2 or more carbon atoms (methyl / hydrocarbon group having 2 or more carbon atoms) in the surface-modified metal oxide particles is added so as to be 0.01 or more and 10 or less.

[0231] Thus, the silane compound can be densely attached to the surface of the metal oxide particles, and the dispersion stability of the metal oxide particles can be improved, and the dispersibility in the methyl-based silicone resin and the phenyl-based silicone resin can be improved.

[0232] The silicone compound added in the 2nd addition step is preferably added to the 2nd dispersion liquid, for example, so as to be 10 mass% or more and 500 mass% or less with respect to the metal oxide particles.

[0233] In the case where the added silicone compound contains at least one of a methyl group and a hydrocarbon group having 2 or more carbon atoms, the methyl group / hydrocarbon group having 2 or more carbon atoms is added so as to be 0.01 or more and 10 or less.

[0234] Thus, a sufficient amount of the silicone compound can be attached to the surface of the metal oxide particles, and the dispersion stability of the metal oxide particles can be improved, and the dispersibility in the silicone resin for LEDs can be improved. Also, the amount of free silicone compound can be reduced, and unintended aggregation of the metal oxide particles in the silicone resin for LEDs can be suppressed.

[0235] Thus, the 3rd dispersion liquid in which the metal oxide particles are surface-modified with the silane compound containing a methyl group and a hydrocarbon group having 2 or more carbon atoms and the silicone compound can be obtained.

[0236] In the dispersion liquid containing the surface-modified metal oxide particles produced using the production method of the surface-modified metal oxide particles according to the present embodiment, the surface of the metal oxide particles is densely and sufficiently modified with the silane compound containing a methyl group and a hydrocarbon group having 2 or more carbon atoms, and furthermore, a silicone compound is present in the vicinity of the surface of the metal oxide particles. Also, the surface modification method of the metal oxide particles according to the present embodiment is capable of densely and sufficiently modifying the surface of the metal oxide particles with the silane compound containing a methyl group and a hydrocarbon group having 2 or more carbon atoms, and furthermore, of causing a silicone compound to be present in the vicinity of the surface of the metal oxide particles. Also, the surface-modified metal oxide particles thus surface-modified are excellent in compatibility with both the methyl-based silicone resin and the phenyl-based silicone resin for LEDs, and can be relatively uniformly dispersed in both of these resins. Therefore, in the case of dispersing the surface-modified metal oxide particles in either the methyl-based silicone resin or the phenyl-based silicone resin, the generation of turbidity such as white turbidity is suppressed. Also, the change in viscosity of the silicone resin for LEDs containing the surface-modified metal oxide particles is suppressed.

[0237] <4. Composition>

[0238] Next, the composition according to the present embodiment will be described.

[0239] The composition according to the present embodiment contains the dispersion liquid containing the above-described surface-modified metal oxide particles and a silicone resin component. That is, the composition according to the present embodiment is a mixture of the above-described dispersion liquid and the silicone resin component. Therefore, the composition according to the present embodiment contains, in addition to the metal oxide particles surface-modified with the above-described silane compound containing a methyl group, or a methyl group and a hydrocarbon group having 2 or more carbon atoms, and the solvent, the silicone resin component.

[0240] Here, the silicone resin component refers to a state having fluidity before the silicone resin is cured.

[0241] The composition according to the present embodiment can be cured as described later and used as a sealing member for a light-emitting element. The composition according to the present embodiment, by containing the metal oxide particles that contribute to the improvement of the above-described refractive index and transparency, can improve the brightness of light of a light-emitting device when used for a sealing member.

[0242] Further, the composition according to the present embodiment contains surface-modified metal oxide particles in which a silane compound and a silicone compound having a hydrocarbon group having 2 or more carbon atoms are attached to the metal oxide particles to the extent that the molar ratio of the above-described methyl group and the hydrocarbon group having 2 or more carbon atoms satisfies the above-described formula (1). Therefore, the aggregation of the metal oxide particles is suppressed regardless of whether the silicone resin component is contained or not, or whether the silicone resin component is cured or not, and thus the decrease in transparency of the composition is suppressed. Therefore, when the composition according to the present embodiment is used for a sealing member, the luminance of light from a light emitting device can be improved.

[0243] The content of the metal oxide particles in the composition according to the present embodiment is preferably 5% by mass or more and 50% by mass or less, more preferably 5% by mass or more and 40% by mass or less, and further preferably 10% by mass or more and 35% by mass or less, from the viewpoint of obtaining a composition having high transparency.

[0244] Further, the content of the silane compound and the silicone compound having a hydrocarbon group having 2 or more carbon atoms can correspond to the content in the surface-modified metal oxide particles according to the present embodiment.

[0245] The silicone resin component is a main component in the composition according to the present embodiment. The silicone resin component is cured when the composition according to the present embodiment is used as a sealing material to seal a light emitting element, and thus prevents a deteriorating factor such as moisture or oxygen from the outside environment from reaching the light emitting element. Further, in the present embodiment, the cured product obtained from the silicone resin component is substantially transparent, and thus light emitted from the light emitting element can be transmitted.

[0246] As the silicone resin component, there is no particular limitation as long as it is an LED silicone resin component used for sealing an LED. The silicone resin component preferably contains a methyl group and a phenyl group. The silicone resin component can be a methyl-based silicone resin component or a phenyl-based silicone resin component. The methyl-based silicone resin component refers to a silicone resin component containing a large amount of methyl groups. The methyl-based silicone resin component can be a methyl-containing silicone resin component, a methylphenyl silicone resin component, or a dimethyl silicone resin component. From the viewpoint of versatility, a methylphenyl silicone resin component is preferable.

[0247] The phenyl-based silicone resin component refers to a silicone resin component containing a large amount of phenyl groups. The phenyl-based silicone resin component can be a phenyl-containing silicone resin component, a methylphenyl silicone resin component, or a diphenyl silicone resin. From the viewpoint of versatility, a methylphenyl silicone resin component is preferable.

[0248] The content of the silicone resin component in the composition according to the present embodiment can be the remainder of the other components, and is preferably 10 mass% or more and 70 mass% or less, for example. The content of the silicone resin component can also be 20 mass% or more and 60 mass% or less, 30 mass% or more and 50 mass% or less, 35 mass% or more and 45 mass% or less.

[0249] The mass ratio of the silicone resin component to the surface-modified metal oxide particles in the composition according to the present embodiment is preferably in the range of 50:50 to 90:10, and more preferably in the range of 60:40 to 80:20, based on silicone resin:surface-modified metal oxide particles.

[0250] The composition according to the present embodiment can contain the solvent derived from the dispersion liquid according to the present embodiment, or can be removed. That is, the solvent derived from the dispersion liquid can be completely removed, or can remain in the composition to the extent of 1 mass% or more and 10 mass% or less, or can remain to the extent of 2 mass% or more and 5 mass% or less.

[0251] The composition according to the present embodiment can also contain a phosphor particle, within a range that does not hinder the object of the present application. The phosphor particle absorbs light of a specific wavelength emitted from a light-emitting element, and emits light of a prescribed wavelength. That is, the wavelength of light can be converted by the phosphor particle, and the color tone can be adjusted.

[0252] The phosphor particle is not particularly limited as long as it can be used in the light-emitting device described later, and can be appropriately selected and used in a manner such that the color of light emitted from the light-emitting device becomes a desired color.

[0253] The content of the phosphor particle in the composition according to the present embodiment can be appropriately adjusted and used so that a desired luminance is obtained.

[0254] Furthermore, within a range that does not hinder the object of the present application, the composition according to the present embodiment can also contain an additive that is generally used, such as a preservative, a polymerization initiator, a polymerization inhibitor, a curing catalyst, a light diffusing agent, and the like. As the light diffusing agent, a silica particle having an average particle diameter of 1 μm or more and 30 μm or less is preferably used.

[0255] The composition according to the present embodiment contains surface-modified metal oxide particles in which the silane compound and the silicone compound each containing a methyl group and a hydrocarbon group having 2 or more carbon atoms at a prescribed ratio are sufficiently attached to the metal oxide particles to satisfy the above formula (1). Therefore, regardless of whether the silicone resin component is a methyl-based silicone resin component or a phenyl-based silicone resin component, the aggregation of the metal oxide particles is inhibited, and the decrease in transparency is inhibited. Therefore, by using the composition according to the present embodiment, a sealing member that improves the brightness of light of a light-emitting device can be formed.

[0256] <5. Method for producing the composition>

[0257] Next, a method for producing the composition according to the present embodiment will be described.

[0258] The method for producing the composition according to the present embodiment has a process H in which a silicone resin component is added to the third dispersion liquid obtained by the above method for producing surface-modified metal oxide particles, and a composition is obtained.

[0259] (Process G (third adding process))

[0260] In the third adding process, the silicone resin component is added to the above third dispersion liquid, and the composition is adjusted to a desired solid content (concentration).

[0261] The content of the silicone resin component contained in the final composition is appropriately adjusted to a desired solid content. The content of the silicone resin component is, for example, preferably 10% by mass or more and 70% by mass or less.

[0262] By the third adding process, a composition adjusted to a desired solid content can be obtained.

[0263] (Process H (removing process))

[0264] In the present embodiment, a process H for removing the solvent contained in the third dispersion liquid can be provided after the process G.

[0265] The removing method is not particularly limited, and, for example, an evaporator can be used. The removing process can be performed until the solvent is completely removed, or about 5% by mass of the solvent can remain.

[0266] Thus, the composition according to the present embodiment can be obtained.

[0267] <6. Sealing member>

[0268] The sealing member according to the present embodiment is a cured product of the composition according to the present embodiment. The sealing member according to the present embodiment is generally used as a sealing member or a part thereof disposed on a light-emitting element.

[0269] The thickness or shape of the sealing member according to the present embodiment can be appropriately adjusted according to the intended use or properties, and is not particularly limited.

[0270] As described above, the sealing member according to the present embodiment can be produced by curing the composition according to the present embodiment. The curing method of the composition can be selected according to the properties of the silicone resin in the composition according to the present embodiment, and examples thereof include thermal curing and electron beam curing. More specifically, the silicone resin in the composition according to the present embodiment is cured by an addition reaction or a polymerization reaction, whereby the sealing member according to the present embodiment can be obtained.

[0271] The average dispersed particle diameter of the metal oxide particles in the sealing member is preferably 10 nm or more and 300 nm or less, more preferably 20 nm or more and 250 nm or less, and further preferably 30 nm or more and 200 nm or less.

[0272] In addition, the average dispersed particle diameter of the metal oxide particles in the sealing member is the number distribution-based average particle diameter (median particle diameter) measured by transmission electron microscope observation (TEM) of the sealing member. Furthermore, the average dispersed particle diameter of the metal oxide particles in the sealing member according to the present embodiment is a value calculated from the dispersed particle diameter of the metal oxide particles in the sealing member. The average dispersed particle diameter is calculated from the diameters of the metal oxide particles in the dispersed state, regardless of whether the metal oxide particles are dispersed in the form of primary particles or secondary particles. Furthermore, in the present embodiment, the average particle diameter of the metal oxide particles in the sealing member can also be measured as the average particle diameter of the metal oxide particles that have been surface-modified by the silane compound and the silicone compound. In the sealing member, there can be metal oxide particles that have been surface-modified by the silane compound and the silicone compound and metal oxide particles that have not been surface-modified by the silane compound and the silicone compound. Therefore, generally, the average particle diameter of the metal oxide particles in the sealing member is measured as a value in the mixed state thereof.

[0273] The sealing member according to the present embodiment is a cured product of the composition according to the present embodiment, and thus has excellent refractive index and transparency. Therefore, according to the present embodiment, a sealing member having excellent extraction efficiency that improves the luminance of light from a light-emitting device can be obtained.

[0274] <7. Light-emitting device>

[0275] Next, the light-emitting device according to the present embodiment will be described. The light-emitting device according to the present embodiment is provided with the sealing member described above and a light-emitting element sealed by the sealing member.

[0276] As the light emitting element, for example, a light emitting diode (LED), an organic light emitting diode (OLED), or the like can be given. In particular, the sealing member according to the present embodiment is suitable for sealing of a light emitting diode.

[0277] Hereinafter, the light emitting device according to the present embodiment will be described taking an example in which the light emitting element is a light emitting diode on a chip, i.e., an LED chip, and the light emitting device is an LED package.

[0278] Figures 1-4 Each is a schematic view (cross-sectional view) showing an example of the light emitting device according to the present embodiment.

[0279] In addition, the size of each member in the drawing is appropriately emphasized for convenience of explanation, and does not represent the actual size or the ratio between the members. In addition, in the present specification and the drawings, the same reference numerals are attached to constituent elements having substantially the same function and structure, and thus repeated explanation is omitted.

[0280] Figure 1 The light emitting device (LED package) 1A shown has a substrate 2 having a recess 21, a light emitting element (LED chip) 3 disposed on the bottom surface of the recess 21 of the substrate 2, and a sealing member 4A sealing in a manner covering the light emitting element 3 in the recess 21.

[0281] The sealing member 4A is composed of the sealing member according to the present embodiment described above. Therefore, in the sealing member 4A, metal oxide particles derived from the composition according to the present embodiment described above are dispersed, as a result of which the extraction efficiency of light in the light emitting device 1A is improved. In addition, in the sealing member 4A, phosphor particles 5 are dispersed. The phosphor particles 5 convert the wavelength of at least a part of the light emitted from the light emitting element 3.

[0282] Figure 2 The light emitting device 1B shown differs from the light emitting device 1A in that the sealing member 4B is two layers. That is, the sealing member 4B has a first layer 41B directly covering the light emitting element 3 and a second layer 43B covering the first layer 41B. Both the first layer 41B and the second layer 43B are the sealing member according to the present embodiment. In the first layer 41B, the phosphor particles 5 are dispersed. On the other hand, the second layer 43B does not contain the phosphor particles 5. The light emitting device 1B improves the brightness of light by dispersing the metal oxide particles derived from the composition according to the present embodiment described above in the first layer 41B and the second layer 43B constituting the sealing member 4B.

[0283] Figure 3The light emitting device 1C shown differs from the light emitting device 1A in that the structure of the sealing member 4C is different from that of the sealing member 4A. The sealing member 4C has a first layer 41C that directly covers the light emitting element 3 and a second layer 43C that covers the first layer 41C. The first layer 41C is not the sealing member according to the present embodiment, but is a sealing member of a resin that does not contain the metal oxide particles described above, and is composed of a resin or the like that can be used for a sealing member. Also, within the first layer 41C, the phosphor particles 5 are dispersed. On the other hand, the second layer 43C is the sealing member according to the present embodiment. The light emitting device 1C has an increased light extraction efficiency by dispersing the metal oxide particles derived from the composition according to the present embodiment described above within the second layer 43C that constitutes the sealing member 4C.

[0284] In Figure 4 In the light emitting device 1D shown, the sealing member 4D has a first layer 41D that directly covers the light emitting element 3, a second layer 43D that covers the first layer 41D, and a third layer 45D that further covers the second layer 43D. The first layer 41D and the second layer 43D are not the sealing member according to the present embodiment, but are sealing members of a resin that does not contain the metal oxide particles described above, and are composed of a resin or the like that can be used for a sealing member. Also, within the second layer 43D, the phosphor particles 5 are dispersed. On the other hand, the third layer 45D is the sealing member according to the present embodiment. The light emitting device 1D has an increased luminance of light by dispersing the metal oxide particles derived from the composition according to the present embodiment described above within the third layer 45D that constitutes the sealing member 4D.

[0285] In addition, the light emitting device according to the present embodiment is not limited to the illustrated mode. For example, the light emitting device according to the present embodiment can not contain phosphor particles in the sealing member. Also, the sealing member according to the present embodiment can exist at any position in the sealing member.

[0286] In the light emitting device according to the present embodiment, the light emitting element is sealed by the sealing member according to the present embodiment, and thus the luminance of light is increased.

[0287] Also, the light emitting device according to the present embodiment seals the light emitting element using the composition according to the present embodiment described above. Therefore, the present application also relates to a method for manufacturing a light emitting device, which in one mode has a step of sealing a light emitting element using the composition according to the present embodiment. In the same mode, the above-described method for manufacturing can also have a step of mixing the dispersion liquid according to the present embodiment and the resin component to obtain the above-described composition.

[0288] In addition, the sealing of the light emitting element can be performed, for example, by applying the composition according to the present embodiment to the light emitting element using a dispenser or the like, and then curing the composition.

[0289] <8. Illumination device, display device>

[0290] The light emitting device according to the present embodiment described above can be used, for example, for an illumination device and a display device. Accordingly, the present application relates to an illumination device or a display device including the light emitting device according to the present embodiment in one embodiment.

[0291] As the illumination device, for example, a general illumination device such as a room light or an outdoor light, an illumination of a switch section of an electronic device such as a mobile phone or an OA device, or the like can be given.

[0292] The illumination device according to the present embodiment includes the light emitting device according to the present embodiment, and thus the light beam emitted can be larger than that of the related art even if the same light emitting element is used, and the surrounding environment can be made brighter.

[0293] As the display device, for example, a mobile phone, a mobile information terminal, an electronic dictionary, a digital camera, a computer, a television, a peripheral device thereof, or the like can be given.

[0294] The display device according to the present embodiment includes the light emitting device according to the present embodiment, and thus the light beam emitted can be larger than that of the related art even if the same light emitting element is used, and, for example, a display with higher clarity and luminance can be performed.

[0295] Embodiment

[0296] Hereinafter, the present application will be described in further detail by way of examples and comparative examples. Note that the examples described below are merely one example of the present application, and the present application is not limited to the examples.

[0297] [Example 1]

[0298] (Preparation of dispersion liquid)

[0299] (1) First hydrolysis step

[0300] As the first silane compound, 90.78 parts by mass of methyltrimethoxysilane (product name: KBM-13, manufactured by Shin-Etsu Chemical Co., Ltd.), 9.21 parts by mass of water, and 0.01 parts by mass of hydrochloric acid (1N) were mixed, and a hydrolysis liquid was obtained. Next, the hydrolysis liquid was stirred at 60°C for 30 minutes, and a hydrolysis treatment of methyltrimethoxysilane was performed, and a hydrolysis liquid was obtained.

[0301] (2) Mixing step (first modification)

[0302] Zirconium oxide (ZrO2) particles (manufactured by Sumitomo Osaka Cement Co., Ltd.) having an average primary particle diameter of 12 nm, 30 parts by mass, and the above hydrolysate, 70 parts by mass, were mixed to obtain a mixed solution. The content of the zirconium oxide particles in the mixed solution was 30 mass%, the content of methyltrimethoxysilane was 63.5 mass%, and the total content of the zirconium oxide particles and methyltrimethoxysilane was 93.5 mass%.

[0303] (3) Dispersion step

[0304] After the mixed solution was subjected to dispersion treatment with a bead mill for 6 hours, the beads were removed to obtain a first dispersion liquid.

[0305] The solid content of the first dispersion liquid was measured (at 100°C for 1 hour), and the result was 70 mass%.

[0306] (4) First addition step

[0307] The obtained first dispersion liquid was heated at 60°C for 2 hours. Next, toluene was added to the dispersion liquid so that the solid content became 40 mass%, and the dispersion liquid was heated at 60°C for 2 hours.

[0308] Next, toluene was added to the dispersion liquid so that the solid content became 30 mass%, and the dispersion liquid was heated at 60°C for 1 hour.

[0309] Next, toluene was added to the dispersion liquid so that the solid content became 20 mass%, and the dispersion liquid was heated at 60°C for 1 hour, thereby obtaining a second dispersion liquid.

[0310] (FT-IR analysis)

[0311] A part of the second dispersion liquid was separated and dried with a vacuum drier. Using 0.01 to 0.05 g of the obtained surface-modified zirconium oxide particles, the transmittance spectrum in the wave number range of 800 cm -1 to 3800 cm -1 was measured with a Fourier transform infrared spectrophotometer (model: FT / IR-670 Plus, manufactured by JASCO Corporation). The transmittance spectrum values were standardized so that the maximum value in the measurement range became 100 and the minimum value became 0, and the standardized spectrum values (IA) in the wave number range of 3500 cm -1 to 1100 cm -1 were calculated. As a result, IA / IB was 7.

[0312] (5) Second hydrolysis step

[0313] As the 2nd silane compound, phenyltrimethoxysilane (product name: KBM-103, manufactured by Shin-Etsu Chemical Co., Ltd.) 91.66 parts by mass, water 8.33 parts by mass, hydrochloric acid (IN) 0.01 part by mass were mixed to obtain a hydrolysis solution. Next, the hydrolysis solution was stirred at 60°C for 30 minutes to perform hydrolysis treatment of phenyltrimethoxysilane, and a hydrolysis solution was obtained.

[0314] (6) 2nd addition step (secondary modification)

[0315] A 2nd dispersion liquid 62.5 parts by mass in which the solid content was adjusted to 15% by mass, the above-mentioned hydrolysis solution of phenyltrimethoxysilane obtained in the 2nd hydrolysis step 6.3 parts by mass, and a silicone compound containing methyl and phenyl (trade name: KR213 (high phenyl content), manufactured by Shin-Etsu Chemical Co., Ltd.) 31.2 parts by mass were mixed, and stirred at 100°C for 3 hours, whereby a dispersion liquid (3rd dispersion liquid) relating to Example 1 was obtained.

[0316] (Evaluation of dispersion liquid)

[0317] (1) FT-IR analysis

[0318] A dispersion liquid 10 g relating to Example 1 in which the solid content was adjusted to 30% by mass with toluene was dried at 100°C and 20 hPa for 2 hours using a vacuum drier (manufactured by EYELA TOKYO RIKAKIKAI CO, LTD., device name: VACUUM OVEN VOS-201 SD). Next, using the obtained metal oxide particles 0.01 g to 0.05 g, the transmittance spectrum in the wave number range of 800 cm -1 to 3800 cm -1 was measured using a Fourier transform infrared spectrophotometer (model: FT / IR-670 Plus, manufactured by JASCO Corporation). The spectrum value was normalized so that the maximum value in the measurement range became 100 and the minimum value became 0, and the value (IA) at 3500 cm -1 and the value (IB) at 1100 cm -1 were calculated. As a result, IA / IB was 1.0. The results are shown in Table 1.

[0319] (2) NMR measurement

[0320] The dispersion 15 g and methanol 15 g of Example 1, which were mixed so that the solid content would be 30 mass% with toluene, were mixed so that the surface-modified zirconia particles would be precipitated. The mixture was subjected to solid-liquid separation using a centrifugal separator, and the solid fraction (surface-modified zirconia particles) was recovered. A few milligrams of the recovered surface-modified zirconia particles were collected and dissolved in chloroform to a mass% of 1. Using this solution, and using a benchtop NMR device (manufactured by Nanalysis Scientific Corp., Model NMReady60Pro (F)), the H-liquid NMR spectrum was measured. From the obtained spectrum, the peak area (integral value) of the phenyl group and the methyl group were calculated respectively, and by calculating the integral value of the methyl group / integral value of the phenyl group, the molar ratio of the methyl group relative to the phenyl group was calculated. The results are shown in Table 1. 1 H / 19 F)), measured the H-liquid NMR spectrum. From the obtained spectrum, the peak area (integral value) of the phenyl group and the methyl group were calculated respectively, and by calculating the integral value of the methyl group / integral value of the phenyl group, the molar ratio of the methyl group relative to the phenyl group was calculated. The results are shown in Table 1. 1 H-liquid NMR spectrum. From the obtained spectrum, the peak area (integral value) of the phenyl group and the methyl group were calculated respectively, and by calculating the integral value of the methyl group / integral value of the phenyl group, the molar ratio of the methyl group relative to the phenyl group was calculated. The results are shown in Table 1.

[0321] The molar ratio of the methyl group relative to the phenyl group (methyl / phenyl) was 0.63. The results are shown in Table 1.

[0322] (Production of Composition A)

[0323] The dispersion 16.7 g of Example 1 and a methyl-based silicone resin component (trade name: KER-2500-A / B, manufactured by Shin-Etsu Chemical Co., Ltd.) 95 g were mixed so that the solid content would be 30 mass% with toluene. Next, toluene was removed from the mixture using an evaporator, whereby the composition A of Example 1 containing the methyl-based silicone resin component was obtained.

[0324] The viscosity of the obtained composition A was measured using a rheometer (trade name: RheoStress RS-6000, manufactured by HAAKE) at 25°C at a shear rate of 1 (1 / s).

[0325] As a result, the viscosity A of the composition A was 21 Pa-s. The results are shown in Table 1.

[0326] (Production of Cured Product A)

[0327] The composition was filled into a 1 mm-thick SUS container coated with Teflon (registered trademark) to a thickness of 1 mm. Next, after heating at 100°C for 2 hours, heating at 150°C for 4 hours was performed, whereby the cured product A of Example 1 was obtained. The thickness of the cured product A extracted from the container was approximately 1 mm.

[0328] The transmittance of the cured product A extracted from the container was measured using a spectrophotometer (manufactured by JASCO Corporation, model: V-770) with an integrating sphere. The transmittance A of the cured product A containing the methyl-based silicone resin was 72%. The results are shown in Table 1.

[0329] (Production of Composition B and Cured Product B)

[0330] The dispersion liquid 16.7 g related to Example 1 and the phenyl-based silicone resin component (trade name: OE-6520, manufactured by Dow Corning Toray Co., Ltd.) 95 g were mixed so that the solid content would be 30% by mass with toluene. Subsequently, toluene was removed from the mixture using an evaporator, thereby obtaining the composition B related to Example 1 containing the phenyl-based silicone resin component. The viscosity B of the composition B measured in the same manner as the composition A is shown in Table 1.

[0331] Subsequently, by performing curing in the same manner as the composition A, the cured product B related to Example 1 was obtained. The thickness of the cured product B extracted from the container was about 1 mm. The transmittance B measured in the same manner as the cured product A is shown in Table 1.

[0332] (Production of LED package and evaluation of luminance)

[0333] (1) Production of composition

[0334] The dispersion liquid 5.0 g related to Example 1 and the methyl-based silicone resin component (trade name: KER-2500-B, manufactured by Shin-Etsu Chemical Co., Ltd.) 3.5 g were mixed so that the solid content would be 30% by mass with toluene. That is, the mixture was performed so that the ratio of the total mass of the zirconia and the surface modification material to the mass of the methyl-based silicone resin component would be 30:70.

[0335] Subsequently, toluene was removed from the mixture using an evaporator, thereby obtaining the composition C related to Example 1 for producing a sealing member.

[0336] (2) Production of LED package

[0337] To the obtained composition Cl, 14 parts by mass of a methyl-based silicone resin component (trade name: KER-2500-A / B, manufactured by Shin-Etsu Chemical Co., Ltd.) was added, adjusted so that the surface-modified zirconia particles were 2% by mass in the composition, and mixed. A composition in which 0.38 parts by mass of phosphor particles (yttrium-aluminum-garnet: YAG) was mixed in 1 part by mass of the composition (total amount of surface-modified zirconia particles and resin: phosphor particles = 100:38) was filled into an LED lead frame at a thickness of 300 μm. Then, it was left to stand at room temperature for 3 hours. Subsequently, the composition was slowly heat-cured to form a sealing member, and a white LED package according to Example 1 was produced.

[0338] (3) Evaluation

[0339] For the obtained white LED package, the brightness was measured by applying a voltage of 3 V and a current of 150 mA to the LED package using a total luminous flux measuring system (manufactured by Otsuka Electronics Co., Ltd.). As a result, the brightness of the white LED package was 75.0 lm. The results are shown in Table 1.

[0340] [Example 2]

[0341] In Example 1, instead of mixing 62.5 parts by mass of the second dispersion liquid, 6.3 parts by mass of the hydrolyzate of phenyltrimethoxysilane, and 31.2 parts by mass of the silicone compound containing methyl and phenyl groups, 60.6 parts by mass of the second dispersion liquid, 9.1 parts by mass of the hydrolyzate of phenyltrimethoxysilane, and 30.3 parts by mass of the silicone compound containing methyl and phenyl groups were mixed, and otherwise, the dispersion liquid according to Example 2 was obtained in the same manner as in Example 1.

[0342] In the same manner as in Example 1, the IA / IB and the methyl / phenyl of the dispersion liquid according to Example 2 were measured. The results are shown in Table 1.

[0343] Using the dispersion liquid according to Example 2 instead of the dispersion liquid according to Example 1, and otherwise, the composition A and the composition B according to Example 2, the cured product A and the cured product B according to Example 2 were obtained in the same manner as in Example 1. The results of measuring the viscosity of the composition and the transmittance of the cured product in the same manner as in Example 1 are shown in Table 1.

[0344] Using the dispersion liquid according to Example 2 instead of the dispersion liquid according to Example 1, and otherwise, the composition C according to Example 2 and the LED package according to Example 2 were obtained in the same manner as in Example 1. The results of the evaluation in the same manner as in Example 1 are shown in Table 1.

[0345] [Example 3]

[0346] In Example 1, instead of mixing the 2nd dispersion liquid 62.5 parts by mass, the hydrolyzate of phenyltrimethoxysilane 6.3 parts by mass, and the silicone compound containing methyl and phenyl groups 31.2 parts by mass, the 2nd dispersion liquid 64.5 parts by mass, the hydrolyzate of phenyltrimethoxysilane 3.2 parts by mass, and the silicone compound containing methyl and phenyl groups 32.3 parts by mass were mixed, and otherwise, the dispersion liquid relating to Example 3 was obtained in the same manner as in Example 1.

[0347] In the same manner as in Example 1, IA / IB and methyl / phenyl of the dispersion liquid relating to Example 3 were measured. The results are shown in Table 1.

[0348] In place of using the dispersion liquid relating to Example 1, the dispersion liquid relating to Example 3 was used, and otherwise, Composition A and Composition B relating to Example 3, cured product A and cured product B relating to Example 3 were obtained in the same manner as in Example 1. The results of measuring the viscosity of the composition and the transmittance of the cured product in the same manner as in Example 1 are shown in Table 1.

[0349] In place of using the dispersion liquid relating to Example 1, the dispersion liquid relating to Example 3 was used, and otherwise, Composition C relating to Example 3 and LED package relating to Example 3 were obtained in the same manner as in Example 1. The results of the evaluation in the same manner as in Example 1 are shown in Table 1.

[0350] [Example 4]

[0351] In Example 1, instead of mixing the 2nd dispersion liquid 62.5 parts by mass, the hydrolyzate of phenyltrimethoxysilane 6.3 parts by mass, and the silicone compound containing methyl and phenyl groups 31.2 parts by mass, the 2nd dispersion liquid 65.4 parts by mass, the hydrolyzate of phenyltrimethoxysilane 2.0 parts by mass, and the silicone compound containing methyl and phenyl groups 32.6 parts by mass were mixed, and otherwise, the dispersion liquid relating to Example 4 was obtained in the same manner as in Example 1.

[0352] In the same manner as in Example 1, IA / IB and methyl / phenyl of the dispersion liquid relating to Example 4 were measured. The results are shown in Table 1.

[0353] In place of using the dispersion liquid relating to Example 1, the dispersion liquid relating to Example 4 was used, and otherwise, Composition A and Composition B relating to Example 4, cured product A and cured product B relating to Example 4 were obtained in the same manner as in Example 1. The results of measuring the viscosity of the composition and the transmittance of the cured product in the same manner as in Example 1 are shown in Table 1.

[0354] The composition C according to Example 4 and the LED package according to Example 4 were obtained in the same manner as in Example 1, except that the dispersion liquid according to Example 4 was used instead of the dispersion liquid according to Example 1.

[0355] [Example 5]

[0356] In Example 1, the 2nd dispersion liquid 62.9 parts by mass, the phenyltrimethoxysilane 5.7 parts by mass, and the silicone compound containing a methyl group and a phenyl group 31.4 parts by mass were mixed instead of mixing the 2nd dispersion liquid 62.5 parts by mass, the hydrolyzate of phenyltrimethoxysilane 6.3 parts by mass, and the silicone compound containing a methyl group and a phenyl group 31.2 parts by mass, and the dispersion liquid according to Example 5 was obtained in the same manner as in Example 1, except for this.

[0357] The IA / IB and the methyl / phenyl of the dispersion liquid according to Example 5 were measured in the same manner as in Example 1. The results are shown in Table 1.

[0358] The composition A and the composition B according to Example 5, the cured product A and the cured product B according to Example 5 were obtained in the same manner as in Example 1, except that the dispersion liquid according to Example 5 was used instead of the dispersion liquid according to Example 1. The results of measuring the viscosity of the composition and the transmittance of the cured product in the same manner as in Example 1 are shown in Table 1.

[0359] The composition C according to Example 5 and the LED package according to Example 5 were obtained in the same manner as in Example 1, except that the dispersion liquid according to Example 5 was used instead of the dispersion liquid according to Example 1. The results of evaluating in the same manner as in Example 1 are shown in Table 1.

[0360] [Comparative Example 1]

[0361] In Example 1, the 2nd dispersion liquid 95.5 parts by mass and the above silicone compound 4.5 parts by mass were mixed instead of mixing the 2nd dispersion liquid 62.5 parts by mass, the hydrolyzate of phenyltrimethoxysilane 6.3 parts by mass, and the silicone compound containing a methyl group and a phenyl group 31.2 parts by mass, in which the solid content was adjusted to 15% by mass with toluene, and the dispersion liquid according to Comparative Example 1 (3rd dispersion liquid) was obtained in the same manner as in Example 1, except for this.

[0362] The IA / IB and the methyl / phenyl of the dispersion liquid according to Comparative Example 1 were measured in the same manner as in Example 1. The results are shown in Table 1.

[0363] A composition A relating to Comparative Example 1 and a cured product A relating to Comparative Example 1 were obtained in the same manner as in Example 1, except that the dispersion liquid relating to Comparative Example 1 was used instead of the dispersion liquid relating to Example 1. The results of measuring the viscosity of the composition and the transmittance of the cured product in the same manner as in Example 1 are shown in Table 1.

[0364] A composition B and a cured product B were obtained in the same manner as in Example 1, using the dispersion liquid relating to Comparative Example 1. However, the dispersion liquid of Comparative Example 1 could not be dispersed in the phenyl-based silicone resin component, and the composition B was whitened and aggregated, so that the cured product B could not be produced.

[0365] A composition C relating to Comparative Example 1 and an LED package relating to Comparative Example 1 were obtained in the same manner as in Example 1, except that the dispersion liquid relating to Comparative Example 1 was used instead of the dispersion liquid relating to Example 1. The results of the evaluation performed in the same manner as in Example 1 are shown in Table 1.

[0366] [Comparative Example 2]

[0367] In the mixing step of Example 1, 20 parts by mass of the above hydrolysis liquid and 50 parts by mass of isopropyl alcohol (IPA) were used instead of 70 parts by mass of the hydrolysis liquid of methyltrimethoxysilane, and the mixing step and the dispersion step were performed in the same manner as in Example 1, to obtain a dispersion liquid (1st dispersion liquid).

[0368] The solid content of the dispersion liquid was measured (at 100°C for 1 hour), and the result was 38 mass%.

[0369] (4) 1st addition step

[0370] Toluene was added to the obtained dispersion liquid (1st dispersion liquid) so that the solid content became 20 mass%, and heated at 60°C for 2 hours. Next, toluene was added to the dispersion liquid in an amount equivalent to the amount of volatilization, and heated at 60°C for 2 hours. Next, toluene was added to the dispersion liquid in an amount equivalent to the amount of volatilization, and heated at 60°C for 1 hour. Next, toluene was added to the dispersion liquid in an amount equivalent to the amount of volatilization, and heated at 60°C for 1 hour, whereby surface modification was promoted, and a dispersion liquid in which isopropyl alcohol was replaced with toluene (2nd dispersion liquid) was obtained.

[0371] (5) 2nd addition step

[0372] The 2nd dispersion liquid in which the solid content was adjusted to 15 mass% was mixed with 11 parts by mass of a silicone compound containing methyl and phenyl (trade name: KR213 (high phenyl content), manufactured by Shin-Etsu Chemical Co., Ltd.), and heated at 110°C for 1 hour, to obtain the dispersion liquid of Comparative Example 2 (3rd dispersion liquid).

[0373] The IA / IB and the methyl / phenyl of the dispersion liquid relating to Comparative Example 2 were measured in the same manner as in Example 1. The results are shown in Table 1.

[0374] Composition B and cured product B relating to Comparative Example 1 were obtained in the same manner as in Example 1, except that the dispersion liquid relating to Comparative Example 2 was used instead of the dispersion liquid relating to Example 1. The results of the viscosity and the transmittance measured in the same manner as in Example 1 are shown in Table 1.

[0375] Composition A and cured product A were obtained in the same manner as in Example 1, using the dispersion liquid relating to Comparative Example 2. However, the dispersion liquid of Comparative Example 2 could not be dispersed in the methyl-based silicone resin component, and composition A was whitened and aggregated, so that cured product A could not be produced.

[0376] [Comparative Example 3]

[0377] In the mixing step of Example 1, 70 parts by mass of the hydrolyzate of phenyltrimethoxysilane obtained in the hydrolysis step of Example 1 was used instead of 70 parts by mass of the hydrolyzate of methyltrimethoxysilane, and the mixing step, the dispersion step, and the 1st addition step were performed in the same manner as in Example 1, to obtain a dispersion liquid (2nd dispersion liquid).

[0378] The 2nd dispersion liquid 89 parts by mass, in which the solid content was adjusted to 15% by mass, and a silicone compound containing methyl and phenyl (trade name: KR213 (high phenyl content), manufactured by Shin-Etsu Chemical Co., Ltd.) 11 parts by mass were mixed, and heated at 110°C for 1 hour, to obtain a dispersion liquid of Comparative Example 3 (3rd dispersion liquid).

[0379] The IA / IB and the methyl / phenyl of the dispersion liquid relating to Comparative Example 3 were measured in the same manner as in Example 1. The results are shown in Table 1.

[0380] Composition B and cured product B relating to Comparative Example 1 were obtained in the same manner as in Example 1, except that the dispersion liquid relating to Comparative Example 3 was used instead of the dispersion liquid relating to Example 1. The results of the viscosity and the transmittance measured in the same manner as in Example 1 are shown in Table 1.

[0381] Composition A and cured product A were obtained in the same manner as in Example 1, using the dispersion liquid relating to Comparative Example 3. However, the dispersion liquid of Comparative Example 3 could not be dispersed in the methyl-based silicone resin component, and composition A was whitened and aggregated, so that cured product A could not be produced.

[0382] [Comparative Example 4]

[0383] In the mixing step of Example 1, 70 parts by mass of the above-mentioned hydrolyzate of phenyltrimethoxysilane was used instead of 70 parts by mass of the hydrolyzate of methyltrimethoxysilane, and otherwise, the mixing step, the dispersing step, and the first adding step were performed in the same manner as in Example 1 to obtain a dispersion liquid (second dispersion liquid).

[0384] The second dispersion liquid 91 parts by mass in which the solid content was adjusted to 15% by mass and the hydrolyzate of methyltrimethoxysilane 9 parts by mass obtained in the hydrolysis step of Example 1 were mixed, and stirred at 130°C for 3 hours to thereby obtain a dispersion liquid of Comparative Example 4 (third dispersion liquid).

[0385] In the same manner as in Example 1, IA / IB and methyl / phenyl relating to Comparative Example 4 were measured. The results are shown in Table 1.

[0386] In the same manner as in Example 1, a composition and a cured product relating to Comparative Example 4 were intended to be obtained using the dispersion liquid relating to Comparative Example 4 instead of using the dispersion liquid relating to Example 1. However, the dispersion liquid of Comparative Example 4 could not be dispersed in either the methyl-based silicone resin or the phenyl-based silicone resin, and both of the compositions A and B were whitened and aggregated. Therefore, neither the cured product A nor the cured product B could be produced.

[0387] [Table 1]

[0388]

[0389] By comparing Example 1 to Example 5 and Comparative Examples 1 to 4, it was confirmed that the zirconia particles in which the surface was modified to the extent that IA / IB ≤ 3.5 using the silane compound containing methyl, the silane compound containing phenyl, and the silicone compound with the ratio of methyl / phenyl being 0.01 or more and 10 or less were well dispersed in both the methyl-based silicone resin containing a large amount of methyl and the phenyl-based silicone resin containing a large amount of phenyl.

[0390] Further, it was confirmed that the viscosity of the composition containing the surface-modified zirconia particles of Example 1 to Example 5 was low. Further, it was confirmed that the brightness of the LED package containing the surface-modified zirconia particles of Example 1 to Example 5 was improved.

[0391] The preferred embodiments of the present application have been described in detail with reference to the accompanying drawings, but the present application is not limited to these examples. It will be understood by those skilled in the art that various changes or modifications can be conceived within the scope of the technical idea recited in the claims, and these naturally belong to the technical scope of the present application.

[0392] Industrial Applicability

[0393] The present application can provide a dispersion liquid containing a surface-modified metal oxide particle that can be dispersed in both a methyl-based silicone resin and a phenyl-based silicone resin, a composition containing the dispersion liquid, a sealing member formed using the composition, a light-emitting device having the sealing member, a lighting appliance provided with the light-emitting device, and a display device.

[0394] REFERENCE NUMERALS

[0395] 1A, 1B, 1C, 1D - Light-emitting device

[0396] 2 - Substrate

[0397] 2a - Substrate upper surface

[0398] 2b - Substrate lower surface

[0399] 21 - Concave portion

[0400] 21a - Concave portion bottom surface

[0401] 3 - Light-emitting element

[0402] 4A, 4B, 4C, 4D - Sealing member

[0403] 41B, 41C, 41D - First layer

[0404] 43B, 43C, 43D - Second layer

[0405] 45D - Third layer

[0406] 5 - Phosphor particle

Claims

1. A dispersion liquid containing metal oxide particles surface-modified with at least one silane compound and at least one silicone compound, and a solvent, wherein the silane compound contains a methyl group and a hydrocarbon group having 2 or more carbon atoms, the molar ratio of the methyl group to the hydrocarbon group in the metal oxide particles, methyl / hydrocarbon group, is 0.01 or more and 10 or less, and IA / IB is 3.5 or less (1).

2. The dispersion liquid according to claim 1, wherein the hydrocarbon group having 2 or more carbon atoms is an aromatic hydrocarbon group.

3. The dispersion liquid according to claim 1, wherein the metal oxide particles surface-modified with the at least one silane compound and the at least one silicone compound are secondary-modified metal oxide particles modified as follows, the metal oxide particles are once modified with a first surface-modification material containing a silane compound containing a methyl group and not containing a hydrocarbon group having 2 or more carbon atoms, and the once-modified metal oxide particles are twice modified with a second surface-modification material containing one or both of a second silane compound containing a methyl group and a hydrocarbon group having 2 or more carbon atoms and a second silane compound not containing a methyl group and containing a hydrocarbon group having 2 or more carbon atoms, and a silicone compound. The metal oxide particles obtained by drying the dispersion under vacuum were measured at 800 cm⁻¹ using a Fourier transform infrared spectrophotometer. -1 Above and 3800cm -1 The following wavenumber range of transmission spectra, when normalized such that the maximum value of the transmission spectrum within the range is 100 and the minimum value is 0, satisfies the following equation (1):

4. The dispersion liquid according to claim 1, wherein the metal oxide particles are zirconia particles or titania particles. where "IA" represents the normalized spectral value at 3500 cm -1 and "IB" represents the normalized spectral value at 1100 cm -1 and "IB" represents the normalized spectral value at 1100 cm 5. A composition which is a mixture of the dispersion liquid according to claim 1 or 2 and a silicone resin component.

6. A sealing member which is a cured product of the composition according to claim 5.

7. A light-emitting device comprising the sealing member according to claim 6 and a light-emitting element sealed by the sealing member.

8. A lighting appliance comprising the light-emitting device according to claim 7.

9. A display device comprising the light-emitting device according to claim 7.

10. A production method of the dispersion liquid according to claim 1 or 2, comprising the following steps: a step of mixing a first surface-modification material and metal oxide particles to obtain a mixed liquid; a step of dispersing the metal oxide particles in the mixed liquid; and a step of adding a second surface-modification material to the mixed liquid to obtain a dispersion liquid, the content of the metal oxide particles in the mixed liquid is 10 mass% or more and 49 mass% or less, the total content of the first surface-modification material and the metal oxide particles in the mixed liquid is 65 mass% or more and 98 mass% or less, the first surface-modification material is a silane compound containing a methyl group, and the second surface-modification material contains a silane compound containing a hydrocarbon group having 2 or more carbon atoms and a silicone compound.

11. The production method of the dispersion liquid according to claim 10, further comprising the following steps: a step of hydrolyzing the first surface-modification material before mixing with the metal oxide particles; and a step of hydrolyzing the second surface-modification material before adding to the mixed liquid, the dispersing step is performed using a disperser.

12. The production method of the dispersion liquid according to claim 10 or 11, wherein the metal oxide particles are zirconia particles or titania particles. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 12. The method for producing a dispersion liquid according to claim 11, wherein one or both of a step of adding a hydrophobic solvent to the mixed solution of the dispersing and a step of removing an alcohol produced in the step of hydrolyzing are included between the step of dispersing and a step of obtaining the dispersion liquid.

13. The method for producing a dispersion liquid according to claim 10, wherein the silane compound containing a methyl group does not contain a hydrocarbon group having 2 or more carbon atoms.

14. A method for surface-modifying metal oxide particles, comprising the following steps: a step of mixing a first surface-modifying material and metal oxide particles to obtain a mixed solution; a step of dispersing the metal oxide particles in the mixed solution; and a step of adding a second surface-modifying material to the mixed solution, a content of the metal oxide particles in the mixed solution is 10% by mass or more and 49% by mass or less, a total content of the first surface-modifying material and the metal oxide particles in the mixed solution is 65% by mass or more and 98% by mass or less, the first surface-modifying material is a silane compound containing a methyl group, the second surface-modifying material includes a silane compound containing a hydrocarbon group having 2 or more carbon atoms and a silicone compound.

15. The method for surface-modifying metal oxide particles according to claim 14, further comprising the following steps: a step of hydrolyzing the first surface-modifying material before being mixed with the metal oxide particles; and a step of hydrolyzing the second surface-modifying material before being added to the mixed solution, the step of dispersing is performed using a disperser.

16. The method for surface-modifying metal oxide particles according to claim 15, wherein one or both of a step of adding a hydrophobic solvent to the mixed solution of the dispersing and a step of removing an alcohol produced in the step of hydrolyzing are included between the step of dispersing and a step of obtaining the dispersion liquid.

17. The method for surface-modifying metal oxide particles according to claim 14, wherein the silane compound containing a methyl group does not contain a hydrocarbon group having 2 or more carbon atoms.

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