JP2023149933A - Dispersion liquid, composition, sealing member, light-emitting device, lighting fixture, display device, and method for producing dispersion liquid - Google Patents

Abstract

To provide a dispersion liquid which can improve brightness of a light-emitting device even if a methyl-based silicone resin is used as a sealing material.SOLUTION: A dispersion liquid contains metal oxide particles which is surface-treated with a surface modification material and has a refractive index of 1.7 or more, and a hydrophobic solvent, wherein the surface modification material contains a silane compound and a silicone compound, and the silane compound contains a methyl group-containing silane compound and a hydrocarbon group-containing silane compound having 2 to 5 carbon atoms. When the transmission spectrum at a wave number of 800 cm-1 or more and 3,800 cm-1 or less for metal oxide particles obtained by vacuum drying of the dispersion liquid is measured with a Fourier transformation infrared spectrophotometer, and the spectrum value is standardized so that a maximum value becomes 100 and a minimum value becomes 0 in the wave number range, the following expression (1): IA/IB≤4.0 is satisfied. In the expression, "IA" represents a spectrum value at 3,500 cm-1, and "IB" represents a spectrum value at 1,100 cm-1.SELECTED DRAWING: None

Description

The present invention relates to a dispersion, a composition, a sealing member, a light-emitting device, a lighting device, a display device, and a method for producing a dispersion for sealing a light-emitting element.

2. Description of the Related Art Light emitting diodes (LEDs) are widely used as light sources that have advantages such as small size, long life, and low voltage operation. The LED chip in the LED package is generally sealed with a resin-containing sealing material to prevent contact with deterioration factors present in the external environment, such as oxygen and moisture. Therefore, the light emitted from the LED chip passes through the sealing material and is emitted to the outside. Therefore, in order to increase the luminous flux emitted from the LED package, it is important to convert the wavelength of the light emitted by the LED chip using phosphor particles and then efficiently extract it to the outside of the LED package.

In order to extend the lifespan of LEDs, there is an increasing demand for highly heat-resistant methyl-based silicone resins as sealing resins used as sealing materials. Methyl silicone resins have a higher content of methyl groups and a higher degree of hydrophobicity than phenyl silicone resins that have been commonly used in the past. Therefore, as described in Patent Document 1, even if metal oxide particles have a hydrophobic surface, when mixed with methyl silicone resin, the metal oxide particles aggregate with each other, resulting in a transparent composition. There was an issue of not being able to get things. Such problems become more noticeable as the content of metal oxide particles in the sealing material increases.

Patent Document 2 proposes a dispersion liquid for sealing a light-emitting element in which agglomeration of metal oxide particles is suppressed even in a highly heat-resistant methyl-based silicone resin by surface modification with a highly concentrated surface modification material. has been done.

International Publication No. 2016/142992 International Publication No. 2020/203462

However, even when the dispersion liquid proposed in Patent Document 2 is used, the brightness of light in a light emitting device using a methyl silicone resin may not be sufficiently improved.

The present invention has been made in view of the above circumstances, and provides a dispersion liquid, a composition, and a composition capable of improving the brightness of a light emitting device even when a methyl silicone resin is used as a sealing material. The present invention aims to provide a sealing member formed using the composition, a light-emitting device having the sealing member, a lighting fixture and a display device including the light-emitting device, and a method for producing a dispersion.

In order to solve the above problems, a first aspect of the present invention provides a dispersion liquid containing metal oxide particles whose surface has been modified with a surface modification material and whose refractive index is 1.7 or more, and a hydrophobic solvent. The surface modification material includes a silane compound and a silicone compound, and the silane compound includes a methyl group-containing silane compound and a hydrocarbon group-containing silane compound having 2 or more and 5 or less carbon atoms, The transmission spectrum of the metal oxide particles obtained by drying the dispersion liquid by vacuum drying was measured using a Fourier transform infrared spectrophotometer in a wave number range of 800 cm ^-1 to 3800 cm ^-1 , and , when the spectrum values are normalized so that the maximum value is 100 and the minimum value is 0, a dispersion liquid that satisfies the following formula (1) is provided.
IA/IB≦4.0 (1)
(In the formula, "IA" indicates the spectral value at 3500 cm ^-1 , and "IB" indicates the spectral value at 1100 cm ^-1 .)

In order to solve the above problems, a second aspect of the present invention provides a composition that is a mixture of the above dispersion and a resin component.

In order to solve the above problems, a third aspect of the present invention provides a sealing member that is a cured product of the above composition.

In order to solve the above problems, a fourth aspect of the present invention provides a light emitting device including the above sealing member and a light emitting element sealed with the above sealing member.

In order to solve the above problems, a fifth aspect of the present invention provides a lighting fixture including the above light emitting device.

In order to solve the above problems, a sixth aspect of the present invention provides a display device including the above light emitting device.

In order to solve the above problems, a seventh aspect of the present invention is a method for producing the dispersion liquid, which comprises mixing a silane compound and metal oxide particles having a refractive index of 1.7 or more to produce a mixed liquid. a step B of dispersing the metal oxide particles in the mixed solution to obtain a first dispersion in which the metal oxide particles are dispersed; and a step C of obtaining a first dispersion in which the metal oxide particles are dispersed, and adding a hydrophobic solvent to the first dispersion. a step D of obtaining a second dispersion liquid, and a step E of adding a silicone compound to the second dispersion liquid to obtain a third dispersion liquid, wherein the silane compound is a methyl group-containing silane. and a hydrocarbon group-containing silane compound having 2 or more and 5 or less carbon atoms, and in the step B, the content of the metal oxide particles in the mixed liquid is 10% by mass or more and 49% by mass or less. and the total content of the silane compound and the metal oxide particles in the mixed solution is 65% by mass or more and 98% by mass or less, and the step D includes heating the first dispersion, and then step d1 of adding the hydrophobic solvent at a rate that does not cause the metal oxide particles to aggregate; step d2 of adding the hydrophobic solvent at a rate that does not cause the metal oxide particles to aggregate while heating the first dispersion; or , step d3 of heating the first dispersion after adding the hydrophobic solvent at a rate that does not cause agglomeration of the metal oxide particles.

According to the present invention, a dispersion liquid, a composition, and a seal formed using the composition can improve the brightness of a light emitting device even when a methyl silicone resin is used as a sealing material. A sealing member, a light-emitting device having the sealing member, a lighting fixture and a display device including the light-emitting device, and a method for producing a dispersion can be provided.

FIG. 1 is a schematic diagram showing an example of a light emitting device of this embodiment. FIG. 7 is a schematic diagram showing another example of the light emitting device of the present embodiment. FIG. 7 is a schematic diagram showing another example of the light emitting device of the present embodiment. FIG. 7 is a schematic diagram showing another example of the light emitting device of the present embodiment. 1 is a field emission transmission electron microscope image of the cured product of Example 1 of the present invention. 1 is a field emission transmission electron microscope image of the cured product of Example 1 of the present invention. 1 is a field emission transmission electron microscope image of a cured product of Comparative Example 1 of the present invention. 1 is a field emission transmission electron microscope image of a cured product of Comparative Example 1 of the present invention.

Embodiments of the dispersion liquid, composition, sealing member, light emitting device, lighting device, display device, and method for manufacturing the dispersion liquid of the present invention will be described.
It should be noted that the present embodiment is specifically explained in order to better understand the gist of the invention, and is not intended to limit the invention unless otherwise specified. Amounts, numbers, types, ratios, configurations, positions, orders, ratios, etc. may be omitted, added, replaced, or changed without departing from the spirit of the present invention.

(Dispersion liquid)
The dispersion liquid of the present embodiment includes metal oxide particles having a refractive index of 1.7 or more whose surface has been modified with a surface modification material, and a hydrophobic solvent, and the surface modification material includes a silane compound and a silicone compound. and the silane compound includes a methyl group-containing silane compound and a hydrocarbon group-containing silane compound having 2 or more and 5 or less carbon atoms, and the metal obtained by drying the dispersion by vacuum drying. The transmission spectrum of the oxide particles was measured using a Fourier transform infrared spectrophotometer in the wave number range of 800 cm ^-1 to 3800 cm ^-1 , and the maximum value was 100 and the minimum value was 0 in the range. A dispersion liquid that satisfies the following formula (1) when the spectral values are normalized.
IA/IB≦4.0 (1)
(In the formula, "IA" indicates the spectral value at 3500 cm ^-1 , and "IB" indicates the spectral value at 1100 cm ^-1 .)
The dispersion liquid of this embodiment is suitably used for sealing a light emitting element.

To explain in detail, in the transmission spectrum measured by a Fourier transform infrared spectrophotometer, the position at a wave number of 1100 cm ^-1 belongs to a siloxane bond (Si-O-Si bond), and the position at a wave number of 3500 cm ^-1 belongs to a siloxane bond (Si-O-Si bond). , belongs to a silanol group (Si-OH group). The silane compound and the silicone compound each have an Si-OH group capable of forming a Si-O-Si bond or a group capable of forming an Si-OH group. Therefore, by comparing the spectral value (IA) at 3500 cm ^-1 and the spectral value (IB) at 1100 cm ^-1 , it is possible to determine the Si-OH group of the silane compound and silicone compound and the group capable of forming an Si-OH group. It becomes possible to observe the degree of reaction.

The present inventors combined metal oxide particles with a refractive index of 1.7 or more with a methyl group-containing silane compound and a hydrocarbon group-containing silane compound with a carbon number of 2 or more and 5 or less (hereinafter referred to as "hydrocarbon group-containing"). If the IA/IB of the surface-modified metal oxide particles is 4.0 or less, when mixed with methyl-based silicone resin, found that agglomeration of metal oxide particles was suppressed.

The background to the idea of the present invention will be explained.
The present inventors used hydrophobic metal oxide particles having a refractive index of 1.7 or more (hereinafter sometimes abbreviated as "surface-modified metal oxide particles") whose surface has been modified with a surface modification material. In order to suppress agglomeration of surface-modified metal oxide particles when dispersed in a high methyl silicone resin, it was considered important to reduce the above IA/IB. In other words, it is believed that if only a methyl group-containing silane compound is used as the silane compound and the surface of the metal oxide particles is not modified to increase the number of siloxane bonds, the surface-modified metal oxide particles will aggregate in the methyl-based silicone resin. was.

The IA/IB value when the surface is modified with a methyl group-containing silane compound and a hydrocarbon group-containing silane compound is higher than the IA/IB of surface-modified metal oxide particles when the surface is modified with a methyl group-containing silane compound only. Of course it was big. However, surprisingly, agglomeration of surface-modified metal oxide particles in methyl-based silicone resin was suppressed more when metal oxide particles were surface-modified with silane compounds containing methyl groups and silane compounds containing hydrocarbon groups. .
From this, in order to suppress the aggregation of surface-modified metal oxide particles in methyl-based silicone resin, it is necessary to closely treat the surface of metal oxide particles with a methyl group-containing silane compound, and to It was also found that it is effective to use a highly hydrophobic silane compound in combination.

When IA/IB exceeds 4.0, the silane compound and the silicone compound are not sufficiently attached to the surface of the metal oxide particles, and as a result, the dispersibility of the metal oxide particles in the methyl silicone resin decreases. It is difficult to make it excellent. As a result, when the dispersion liquid and the methyl-based silicone resin are mixed, the metal oxide particles agglomerate and the resulting composition becomes cloudy. As mentioned above, IA/IB is 4.0 or less, preferably 3.8 or less, more preferably 3.6 or less, even more preferably 3.5 or less, 3 It is particularly preferable that it is .4 or less.

Further, the lower limit value of IA/IB is 0 because IA=0 is preferable. However, even if a small amount of silanol groups (Si--OH groups) remain, they can be mixed with the methyl silicone resin. Therefore, the lower limit value of IA/IB may be 0, 1.0, 1.5, 2.0, 2.3, and so on. It may be 2.5.

Note that measurement of the transmission spectrum of metal oxide particles using a Fourier transform infrared spectrophotometer (FT-IR) can be carried out as follows, to give a specific example.
First, the dispersion liquid of this embodiment is dried by vacuum drying. The drying conditions may be adjusted as appropriate depending on the amount and concentration of the dispersion. For example, 10 g of a dispersion having a solid concentration of 30% by mass may be dried at 100° C. and 20 hPa or less for 2 hours or more. As the vacuum dryer, VACUUM OVEN VOS-201SD manufactured by EYELA Tokyo Rikakikai Co., Ltd., etc. can be used.
Next, by using 0.01 g to 0.05 g of the metal oxide particles obtained by drying, it was measured with a Fourier transform infrared spectrophotometer (for example, model number: FT/IR-670 Plus, manufactured by JASCO Corporation). , the transmission spectrum can be measured.

The metal oxide particles having a refractive index of 1.7 or more in this embodiment are surface-modified with a methyl group-containing silane compound, a hydrocarbon group-containing silane compound, and a silicone compound by the method described below. Therefore, in the methyl silicone resin, light with a wavelength of 450 nm is easily scattered, and light with a wavelength of 600 nm can be aggregated to a size that is difficult to scatter. Therefore, when a light emitting element is sealed using the dispersion liquid of this embodiment, the brightness of the light emitting device can be improved.

The dispersion liquid of this embodiment and methylphenyl silicone are mixed so that the mass ratio of the total mass of metal oxide particles and surface modification material to methylphenyl silicone is 3:97, and a cured product with a thickness of 1 mm is prepared. In this case, it is preferable that the value obtained by dividing the amount of scattering at a wavelength of 450 nm of the cured product by the amount of scattering at a wavelength of 600 nm of the cured product is 1.0 or more.

In this embodiment, the "scattering component" means a value obtained by subtracting the value of linear transmittance (%) from the value of integrated transmittance (%). Integrated transmittance means transmittance measured using an integrating sphere with a spectrophotometer. Linear transmittance means transmittance measured with a spectrophotometer without using an integrating sphere.

The value obtained by dividing the amount of scattering at a wavelength of 450 nm of the cured product by the amount of scattering at a wavelength of 600 nm of the cured product is 1.0 or more, preferably 1.1 or more, and 1.2 or more. is more preferable, and even more preferably 1.3 or more. The upper limit of the value obtained by dividing the amount of scattering at a wavelength of 450 nm of the cured product by the amount of scattering at a wavelength of 600 nm of the cured product is not particularly limited, and may be 2.0 or less, and may be 1.8 or less. may be 1.7 or less, or 1.6 or less.
Since the value obtained by dividing the amount of scattering at a wavelength of 450 nm of the cured product by the amount of scattering at a wavelength of 600 nm of the cured product is 1.0 or more, light on the low wavelength side is scattered, while light on the high wavelength side is scattered. Since the scattering of light is suppressed, the brightness of the light from the light emitting device can be improved.

Since the dispersion of this embodiment uses surface-modified metal oxide particles obtained by the manufacturing method described below, it is believed that the agglomeration state of the surface-modified metal oxide particles in the sealing member can be controlled to a desired size. It will be done. In other words, by directly dispersing metal oxide particles in a methyl group-containing silane compound and a hydrocarbon group-containing silane compound, aggregation of surface-modified metal oxides can be suppressed even if the resin component is a methyl-based silicone resin. Became. It is presumed that the surface-modified metal oxide particles in this embodiment have a large amount of silane compound attached to the metal oxide particles, provide a dense coating, and have high compatibility with the methyl-based silicone resin.
Note that it is unclear whether the condition of the surface of the metal oxide particles suppresses aggregation of the surface-modified metal oxide particles in the methyl-based silicone resin. Therefore, it is difficult to directly identify the characteristics of the dispersion liquid of this embodiment based on the surface state of the metal oxide particles modified with the methyl group-containing silane compound, the hydrocarbon group-containing silane compound, and the silicone compound.
The fact that surface-modified metal oxide particles can be dispersed in a sealing member to obtain desired optical properties depends on the structure of the surface-modified material, the degree of polymerization of the surface-modified material, the characteristics of the metal oxide particles, and the sealing resin. This is because it is thought to be caused by a complex interplay of many factors, such as the characteristics of

Each component included in this embodiment will be explained below.
(metal oxide particles)
The metal oxide particles scatter light emitted from the light emitting element in the sealing member described below. Furthermore, depending on the type of metal oxide particles, the refractive index of the sealing member can be improved. Due to these, metal oxide particles contribute to improving the brightness of light in a light emitting device.

The metal oxide particles having a refractive index of 1.7 or more are not particularly limited as long as they can improve the brightness of the light emitting device. Examples of the metal oxide particles in this embodiment include zirconium oxide particles, aluminum oxide particles, titanium oxide particles, zinc oxide particles, iron oxide particles, copper oxide particles, tin oxide particles, cerium oxide particles, tantalum oxide particles, Niobium particles, tungsten oxide particles, europium oxide particles, yttrium oxide particles, molybdenum oxide particles, indium oxide particles, antimony oxide particles, germanium oxide particles, lead oxide particles, bismuth oxide particles, and hafnium oxide particles as well as potassium titanate particles, titanium barium acid particles, strontium titanate particles, potassium niobate particles, lithium niobate particles, calcium tungstate particles, yttria stabilized zirconia particles, alumina stabilized zirconia particles, calcia stabilized zirconia particles, magnesia stabilized zirconia particles, scandia stabilized oxidized zirconia particles, hafnia-stabilized zirconia particles, Ytterbia-stabilized zirconia particles, ceria-stabilized zirconia particles, india-stabilized zirconia particles, strontium-stabilized zirconia particles, samarium oxide-stabilized zirconia particles, gadolinium oxide-stabilized zirconia particles, antimony added At least one selected from the group consisting of tin oxide particles and indium-added tin oxide particles is preferably used.
Among the above, from the viewpoint of improving transparency and compatibility (affinity) with the sealing resin (resin component), the metal oxide particles are selected from the group consisting of zirconium oxide particles, aluminum oxide particles, and titanium oxide particles. It is preferable to include at least one selected type, more preferably to use at least one of zirconium oxide particles and aluminum oxide particles, and even more preferably to use zirconium oxide particles.
If the refractive index of the metal oxide particles is too high, the brightness of the light emitting device may not be improved. Therefore, the upper limit of the refractive index of the metal oxide particles is preferably 3.0 or less, more preferably 2.5 or less.

Note that the metal oxide particles may be dispersed in the dispersion liquid as primary particles, or may be dispersed as secondary particles obtained by agglomerating primary particles. Usually, metal oxide particles are dispersed as secondary particles.

In the dispersion of the present embodiment, the average dispersed particle size of the metal oxide particles is not particularly limited as long as the dispersed particle size (agglomerated particle size) in the sealing member is 60 nm or more and 1000 nm or less. The average dispersed particle diameter of the metal oxide particles may be, for example, 30 nm or more and 1000 nm or less, 50 nm or more and 800 nm or less, or 60 nm or more and 700 nm or less.
The agglomeration state of metal oxide particles in the cured product changes depending on the combination of metal oxide particles, surface modification material, resin component, and phosphor particles and the curing conditions of the composition, so the wavelength of the above 1 mm thick cured product varies. The average dispersed particle size of the metal oxide particles in the dispersion may be adjusted while also checking the scattering characteristics at wavelengths of 450 nm and 600 nm.
The average dispersed particle diameter of metal oxide particles can be measured using, for example, a particle size distribution device.

Note that the average dispersed particle diameter of metal oxide particles is determined by the diameter of the metal oxide particles in the dispersed state, regardless of whether the metal oxide particles are dispersed as primary particles or secondary particles. Measured and calculated based on Furthermore, in the present embodiment, the average dispersed particle size of the metal oxide particles may be measured as the average dispersed particle size of the metal oxide particles to which the surface modification material is attached. In the dispersion, there may 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, the average dispersed particle size of metal oxide particles is usually measured as a value in a mixed state of these particles.

Although the average primary particle diameter of the metal oxide particles can be arbitrarily selected, for example, it is preferably 3 nm or more and 200 nm or less, more preferably 5 nm or more and 170 nm or less, and even more preferably 10 nm or more and 100 nm or less. . The average primary particle diameter of the metal oxide particles may be 5 nm or more and 20 nm or less, 5 nm or more and 25 nm or less, 50 nm or more and 120 nm or less, or 50 nm or more and 150 nm or less, as necessary. good. It is preferable that the average primary particle diameter of the metal oxide particles is within the above range because it facilitates control of the scattering properties of the cured product at a wavelength of 450 nm and the scattering properties of the cured product at a wavelength of 600 nm.

The average primary particle diameter of metal oxide particles can be measured by any method selected. For example, this can be performed by observation using a transmission electron microscope. For example, a predetermined number, for example 100, of metal oxide particles in a transmission electron microscope image are selected using a transmission electron microscope. Then, the longest straight line segment (maximum major axis) of each of these metal oxide particles is measured, and these measured values are arithmetic averaged to determine the average primary particle diameter of the metal oxide particles.

Here, when the metal oxide particles are aggregated, the agglomerated particle diameter of this aggregate is not measured. A predetermined number of maximum major diameters of metal oxide particles (primary particles) constituting this aggregate are measured and taken as an average primary particle diameter.

The content of metal oxide particles in the dispersion is not particularly limited as long as they can be mixed with the resin component described below. The content of metal oxide particles in the dispersion can be arbitrarily selected, but for example, it is preferably 1% by mass or more and 70% by mass or less, more preferably 5% by mass or more and 50% by mass or less, and 7% by mass or more. It is more preferably 10% by mass or more and 30% by mass or less, and particularly preferably 10% by mass or more and 30% by mass or less. If necessary, the content may be 20% by mass or more and 40% by mass or less, or 25% by mass or more and 35% by mass or less.

Such an amount can prevent the viscosity of the dispersion from increasing excessively. Therefore, mixing with the resin component described later becomes easy. Further, it is possible to prevent the amount of solvent (dispersion medium) from becoming excessive after mixing with the resin component, and the removal of the solvent becomes easy.

A surface modification material described below is attached to the surface of the metal oxide particles described above. This attachment allows the metal oxide particles to be dispersed in the resin component with a desired particle size.

(Surface modification material)
The dispersion liquid of this embodiment contains a silane compound and a silicone compound as surface modification materials, and the silane compound contains a methyl group-containing silane compound and a hydrocarbon group-containing silane compound having 2 or more and 5 or less carbon atoms. As the surface modification material in this embodiment, only a silane compound and a silicone compound may be used.
At least a portion of the surface modification material adheres to the surface of the metal oxide particles in the dispersion of the present embodiment and modifies the surface, thereby preventing agglomeration of the metal oxide particles. Furthermore, the adhesion improves compatibility with the resin component.

Here, the surface modification material "adheres" to the metal oxide particles means that the surface modification material contacts or bonds to the metal oxide particles through mutual interaction or reaction. Examples of contact include physical adsorption. Further, examples of the bond include an ionic bond, a hydrogen bond, and a covalent bond.
In this embodiment, the metal oxide particles may be surface-modified with at least a silane compound and a silicone compound.

Silane compounds tend to adhere to the vicinity of the surfaces of metal oxide particles. On the other hand, the silicone compound has a relatively large molecular weight and mainly contributes to improving the affinity with the dispersion medium and the resin component. By using such a silane compound, the dispersion stability of metal oxide particles in the resin component is improved.
It is preferable to use a silane compound and a silicone compound together because the dispersion stability of the metal oxide particles in the resin component is further improved.
Components other than the silane compound and silicone compound may be included as the surface modification material as long as they do not impede the object of the present invention. Examples of such components include fatty acids containing carbon-carbon unsaturated bonds, specifically methacrylic acid, acrylic acid, and the like.

(silane compound)
The silane compound in this embodiment includes a methyl group-containing silane compound and a hydrocarbon group-containing silane compound having 2 or more and 5 or less carbon atoms. By surface-modifying the metal oxide particles with a methyl group-containing silane compound and a hydrocarbon group-containing silane compound having 2 to 5 carbon atoms using the manufacturing method described below, even methyl-based silicone resins can be sealed. Excessive aggregation of metal oxide particles in the stopper member can be suppressed.

(Methyl group-containing silane compound)
From the viewpoint of low viscosity and easy dispersion of metal oxide particles in the dispersion step described below, the methyl group-containing silane compound preferably further contains an alkoxy group.
The number of alkoxy groups in such a 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 alkoxy groups may be 1 or 2, if necessary. Although the number of carbon atoms in the alkoxy group can be selected arbitrarily, it is preferably 1 or more and 5 or less. The number of carbon atoms in the alkoxy group may be 1 or more and 3 or less, or 2 or more and 4 or less.

Examples of such methyl group-containing silane compounds include methyltrimethoxysilane, methyltriethoxysilane, methyltripropoxysilane, methyltributoxysilane, diethoxymonomethylsilane, monoethoxydimethylsilane, dimethylchlorosilane, methyldichlorosilane, etc. can be mentioned. The methyl group-containing silane compound can preferably contain at least one selected from the group consisting of the above compounds. It is preferable to use methyltrimethoxysilane and methyltriethoxysilane because they tend to adhere to the surface of metal oxide particles. In terms of improving the dispersion stability of the surface-modified metal oxide particles, it is preferable to use methyltriethoxysilane.

(silane compound containing a hydrocarbon group having 2 or more and 5 or less carbon atoms)
From the viewpoint of low viscosity and easy dispersion of metal oxide particles in the dispersion step described below, the hydrocarbon group-containing silane compound having 2 or more and 5 or less carbon atoms preferably further contains an alkoxy group.
The number of alkoxy groups in the silane compound containing a hydrocarbon group having 2 or more and 5 or less carbon atoms and an alkoxy group is preferably 1 or more and 3 or less, and more preferably 3. The number of alkoxy groups may be 1 or 2, if necessary. Although the number of carbon atoms in the alkoxy group can be selected arbitrarily, it is preferably 1 or more and 5 or less. The number of carbon atoms in the alkoxy group may be 1 or more and 3 or less, or 2 or more and 4 or less.

The hydrocarbon group having 2 or more and 5 or less carbon atoms is not particularly limited as long as it is easily compatible with the resin component. Considering the ease of surface modification of the metal oxide particle surface, the number of carbon atoms is more preferably 2 or more and 4 or less.
The hydrocarbon group having 2 or more and 5 or less carbon atoms may be a chain aliphatic hydrocarbon group or a cyclic aliphatic hydrocarbon group.

The hydrocarbon group having 2 or more and 5 or less carbon atoms may be an alkyl group, an alkenyl group, or an alkynyl group.
As the alkyl group, for example, an ethyl group, a propyl group, a butyl group, and a pentyl group can be used. As the alkenyl group, for example, a vinyl group, an allyl group, a propenyl group, a butenyl group, etc. can be used. As the alkynyl group, an ethynyl group, a propynyl group, a butynyl group, etc. can be used.

Examples of such hydrocarbon group-containing silane compounds having 2 to 5 carbon atoms include ethyltrimethoxysilane, ethyltriethoxysilane, ethyltripropoxysilane, propyltrimethoxysilane, propyltriethoxysilane, and isobutyltrimethoxysilane. Examples include silane, vinyltrimethoxysilane, diethylchlorosilane, and ethyldichlorosilane. These hydrocarbon group-containing silane compounds having 2 or more and 5 or less carbon atoms may be used alone or in combination of two or more. Among these, silane compounds having an alkoxy group, particularly a methoxy group, are preferred because they tend to adhere to metal oxide particles. Among these, silane compounds having an ethoxy group are preferred in terms of improving the dispersion stability of surface-modified metal oxide particles.

The mass ratio of the methyl group-containing silane compound and the hydrocarbon group-containing silane compound having 2 to 5 carbon atoms is preferably in the range of 99:1 to 35:65. The mass ratio may be 99:1 to 45:65, 99:1 to 50:50, or 99:1 to 60:40. By setting the mass ratio of the methyl group-containing silane compound to the hydrocarbon group-containing silane compound having 2 to 5 carbon atoms within the above range, the metal oxide particles are finely surface-modified and mixed with the methyl-based silicone resin. Even in cases where surface-modified metal oxide particles are prevented from agglomerating excessively.

The content of the silane compound in the dispersion can be arbitrarily selected and is not particularly limited, but it is preferably, for example, 50 parts by mass or more and 500 parts by mass or less, and 70 parts by mass, based on 100 parts by mass of the metal oxide particles. It is more preferably 400 parts by mass or less, and even more preferably 90 parts by mass or more and 300 parts by mass or less. If necessary, the content of the silane compound in the dispersion may be 80 parts by mass or more and 350 parts by mass or less, or 150 parts by mass or more and 250 parts by mass or less. Thereby, a sufficient amount of the silicone compound can be attached to the surface of the metal oxide particles via the silane compound. Therefore, the dispersion stability of the metal oxide particles can be improved, and even if the resin component is a methyl silicone resin, the dispersibility of the metal oxide particles into the resin component can be improved.

(Silicone compound)
The silicone compound can be arbitrarily selected, and examples include alkoxy group-containing phenyl silicone, dimethyl silicone, methyl phenyl silicone, methyl hydrogen silicone, methyl phenyl hydrogen silicone, diphenyl hydrogen silicone, alkoxy-terminated phenyl silicone, alkoxy-terminated methyl Examples include phenyl silicone, alkoxy group-containing methylphenyl silicone, alkoxy group-containing dimethyl silicone, alkoxy one end trimethyl end (methyl group one end) dimethyl silicone, and alkoxy group containing phenyl silicone. These silicone compounds may be used alone or in combination of two or more.
The silicone compound may be a monomer, an oligomer, or a resin (polymer). It is preferable to use monomers or oligomers because surface modification is easy.

Among the above, from the viewpoint of ease of reaction and high hydrophobicity, the silicone compound is preferably alkoxy group-containing phenyl silicone, dimethyl silicone, methylphenyl silicone, alkoxy-terminated phenyl silicone, alkoxy-terminated methylphenyl silicone, Examples thereof include alkoxy group-containing methylphenyl silicone, alkoxy group-containing dimethyl silicone, alkoxy group-containing trimethyl end (methyl group end) dimethyl silicone, and alkoxy group-containing phenyl silicone. It can contain at least one selected from the group consisting of these compounds. More preferably, the silicone compound includes at least one selected from the group consisting of methoxy group-containing phenyl silicone, dimethyl silicone, and methoxy group-containing dimethyl silicone.

The content of the silicone compound in the dispersion can be arbitrarily selected and is not particularly limited. For example, with respect to 100 parts by mass of metal oxide particles, the amount is preferably 50 parts by mass or more and 500 parts by mass or less, more preferably 80 parts by mass or more and 400 parts by mass or less, and 100 parts by mass or more and 300 parts by mass. It is more preferable that the amount is less than 1 part. If necessary, the content of the silicone compound in the dispersion may be 50 parts by mass or more and 200 parts by mass or less, or 50 parts by mass or more and 150 parts 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, as well as the dispersibility in the resin component. Furthermore, the amount of liberated silicone compounds can be reduced, and unintended aggregation of metal oxide particles in the resin component can be suppressed.

(Total content of silane compounds and silicone compounds)
The total content of the silane compound and the silicone compound is not particularly limited and can be arbitrarily selected. For example, it is preferably 100 parts by mass or more and 1000 parts by mass or less, more preferably 150 parts by mass or more and 800 parts by mass or less, and 190 parts by mass or more and 600 parts by mass or less, based on 100 parts by mass of metal oxide particles. It is more preferable that The total content of the silane compound and the silicone compound may be 200 parts by mass or more and 900 parts by mass or less, or 250 parts by mass or more and 850 parts by mass or less. When the total content of the silane compound and the silicone compound is within the above range, the dispersibility of the metal oxide particles can be sufficiently improved while reducing the amount of surface modification material released.

(hydrophobic solvent)
The dispersion liquid of this embodiment contains a hydrophobic solvent in which the surface-modified metal oxide particles are dispersed as a dispersion medium. This hydrophobic solvent is not particularly limited as long as it can disperse the metal oxide particles to which the surface modification material is attached and can be mixed with the resin component described below.
Examples of such hydrophobic solvents include aromatics, saturated hydrocarbons, and unsaturated hydrocarbons. These hydrophobic solvents may be used alone or in combination of two or more.
Examples of such hydrophobic solvents include aromatics, saturated hydrocarbons, and unsaturated hydrocarbons. These hydrophobic solvents may be used alone or in combination of two or more.

Among the above-mentioned hydrophobic solvents, aromatics, particularly aromatic hydrocarbons are preferable. Aromatics have excellent compatibility with the resin component, and thereby contribute to improving the viscosity characteristics of the resulting composition and the quality (transparency, shape, etc.) of the formed sealing member.

Such aromatic hydrocarbons include, for example, benzene, toluene, ethylbenzene, 1-phenylpropane, isopropylbenzene, n-butylbenzene, tert-butylbenzene, sec-butylbenzene, o-xylene, m-xylene or p-xylene. -xylene, 2-ethyltoluene, 3-ethyltoluene, or 4-ethyltoluene. These aromatic hydrocarbons may be used alone or in combination of two or more.

Among the above-mentioned hydrophobic solvents, from the viewpoint of stability of the dispersion liquid and ease of handling during the removal of the hydrophobic solvent during the production of the composition described below, the hydrophobic solvent is toluene, o-xylene, m-xylene or At least one selected from the group consisting of p-xylene and benzene is particularly preferably used.

The content of the hydrophobic solvent contained in the dispersion liquid can be arbitrarily selected, and may be adjusted as appropriate to obtain a desired solid content concentration. The content of the hydrophobic 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 60% by mass or more and 80% by mass or less. is even more preferable. This makes it easier to mix the dispersion liquid with the resin component described below, especially the methyl silicone resin. If necessary, the content of the hydrophobic solvent may be 60% by mass or more and 90% by mass or less, 65% by mass or more and 85% by mass or less, or 70% by mass or more and 80% by mass or less.
In this embodiment, the solid content refers to the residue after removing volatile components. For example, if 1.2 g of the dispersion is placed in a magnetic crucible and heated on a hot plate at 150°C for 1 hour, the remaining components (metal oxide particles, surface modification materials, etc.) that do not volatilize will be classified as solid content. can do.

(hydrophilic solvent)
The dispersion liquid of this embodiment may contain a hydrophilic solvent. Hydrophilic solvents may be included in the dispersion, for example due to the methods described below. Examples of such hydrophilic solvents include alcohol solvents, ketone solvents, nitrile solvents, and the like. These hydrophilic solvents may be used alone or in combination of two or more.

Examples of alcoholic solvents include branched or linear alcohol compounds having 1 to 4 carbon atoms and ether condensates thereof. These alcoholic solvents may be used alone or in combination of two or more. Further, the alcohol compound contained in the alcohol solvent may be any of primary alcohol, secondary alcohol, and tertiary alcohol. Further, the alcohol compound contained in the alcohol solvent may be any of monohydric alcohol, dihydric alcohol, and trihydric alcohol. More specifically, examples of alcoholic solvents include methanol, ethanol, 1-propanol, isopropyl alcohol, 1-butyl alcohol, 2-butanol, isobutyl alcohol, tert-butyl alcohol, methanediol, and 1,2-ethane. Diol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 2-butene-1, Examples include 4-diol, 1,4-butynediol, glycerin, diethylene glycol, 3-methoxy-1,2-propanediol, and the like.

Examples of the ketone solvent include acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone.
Examples of nitrile solvents include acetonitrile and the like.

From the viewpoint of having excellent affinity between water and a hydrophobic solvent and promoting their mixing, the hydrophilic solvent preferably includes an alcohol solvent. In this case, the number of carbon atoms in the alcohol compound constituting the alcohol solvent is preferably 1 or more and 3 or less, more preferably 1 or more and 2 or less.
Among the hydrophilic solvents, methanol and ethanol, particularly methanol, can be preferably used because they can fully exhibit the effects of the alcoholic solvents described above.

Further, 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, even more preferably 5% by mass or less, and 3% by mass or less. % or less is particularly preferable. The content of the hydrophilic solvent may be 0% by mass.

(Other ingredients)
The dispersion liquid of this embodiment may also contain components other than those mentioned above. For example, the dispersion liquid of this embodiment may contain ingredients other than those mentioned above, such as general dispersants, dispersion aids, antioxidants, fluidity regulators, thickeners, pH adjusters, preservatives, etc., as necessary. It may also contain additives etc.
Further, the dispersion liquid of this embodiment may contain components that may be included due to the method described below, such as acid, water, alcohol, etc.

In addition, in this specification, the dispersion liquid of this embodiment contains a resin component, and is distinguished from the composition of this embodiment which can form a sealing member by hardening. That is, even if the dispersion liquid of this embodiment contains the resin component described below, it does not contain the resin component described below in an amount that can form a sealing member when simply cured. More specifically, the mass ratio of the resin component to the metal oxide particles in the dispersion of the present embodiment is preferably in the range of 0:100 to 40:60 (resin component: metal oxide particles). , more preferably in the range of 0:100 to 30:70, and still more preferably in the range of 0:100 to 20:80. The dispersion liquid of this embodiment particularly preferably does not essentially contain the resin component described below, and most preferably does not contain the resin component described below completely.

In the dispersion liquid of this embodiment, the surfaces of metal oxide particles having a refractive index of 1.7 or more are sufficiently modified with a surface modification material by a manufacturing method described later. The metal oxide particles modified in this manner have excellent affinity even with methyl-based silicone resins, and can be dispersed in a desired dispersion state with excellent scattering properties even in methyl-based silicone resins.

(Method for manufacturing dispersion)
The method for producing a dispersion liquid of the present embodiment includes a step B of mixing a silane compound and metal oxide particles having a refractive index of 1.7 or more to obtain a mixed liquid;
Step C of dispersing the metal oxide particles in the mixed liquid to obtain a first dispersion liquid in which the metal oxide particles are dispersed;
Step D of adding a hydrophobic solvent to the first dispersion to obtain a second dispersion;
a step E of adding a silicone compound to the second dispersion to obtain a third dispersion;
The silane compound includes a methyl group-containing silane compound and a hydrocarbon group-containing silane compound having 2 or more and 5 or less carbon atoms,
In the step B, the content of the metal oxide particles in the mixed liquid is 10% by mass or more and 49% by mass or less, and the total content of the silane compound and the metal oxide particles in the mixed liquid is is 65% by mass or more and 98% by mass or less,
The step D includes heating the first dispersion liquid and then adding the hydrophobic solvent at a rate that does not cause the metal oxide particles to aggregate. Step d1 is adding the hydrophobic solvent while heating the first dispersion liquid. Either step d2 of adding the hydrophobic solvent at a rate that does not cause the metal oxide particles to aggregate, or step d3 of heating the first dispersion after adding the hydrophobic solvent at a rate that does not cause the metal oxide particles to aggregate. It is.

The mass ratio of the methyl group-containing silane compound to the hydrocarbon group-containing silane compound having 2 to 5 carbon atoms is preferably in the range of 99:1 to 35:65. The mass ratio may be 99:1 to 45:65, 99:1 to 50:50, or 99:1 to 60:40.

Note that the total content of the silane compound and the metal oxide particles can also be evaluated based on solid content.

The total content of the silane compound and the metal oxide particles does not include alcohol generated by hydrolysis of the silane compound, which will be described later. That is, the total content of the silane compound and the metal oxide particles means the total content of the silane compound, the hydrolyzed silane compound, and the metal oxide particles. It goes without saying that the above total content includes the content of metal oxide particles attached to the silane compound.

Further, in the present embodiment, prior to each of the above steps, a step A (hydrolysis step) of mixing a silane compound and water to obtain a hydrolysis liquid containing a hydrolyzed silane compound may be included. good.
Hereinafter, each step for obtaining the dispersion liquid of this embodiment will be explained in detail.

(Step A (hydrolysis step))
In the hydrolysis step, at least a silane compound and water are mixed to obtain a hydrolysis liquid containing a hydrolyzed silane compound. By using a liquid mixture in which at least a portion of the silane compound has been hydrolyzed in advance in this manner, the silane compound is likely to adhere to the metal oxide particles in the dispersion step described later.

The content of the silane compound in the hydrolysis solution is not particularly limited. It can be the remainder after removing other components from the hydrolyzed solution, but for example, it 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, It is more preferably 80% by mass or more and 95% by mass or less. The content of the silane compound in the hydrolysis liquid may be 85% by mass or more and 95% by mass or less, or 87% by mass or more and 93% by mass or less, as necessary.

In addition, in the hydrolysis step, a surface modification material other than the silane compound may be contained in the hydrolysis solution.

Moreover, in the hydrolysis step, the hydrolysis liquid contains water. Water serves as a substrate for the hydrolysis reaction of surface modification materials such as silane compounds.
The content of water in the hydrolysis solution is not particularly limited and can be arbitrarily selected. For example, the water content can be appropriately set depending on the amount of the 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 0.7 mol or less, per 1 mol of the silane compound. More preferably, the amount is 2 mol or less. This makes it possible to sufficiently advance the hydrolysis reaction of the silane compound while more reliably preventing agglomeration of metal oxide particles in the dispersion produced using an excessive amount of water.

Alternatively, the content of water in the hydrolysis solution is, for example, preferably 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 1% by mass or more and 10% by mass. % or less is more preferable.

Moreover, a catalyst may be added to the hydrolysis liquid together with a silane compound and water. As the catalyst, for example, an acid or a base can be used.
The acid catalyzes the hydrolysis reaction of the silane compound in the hydrolysis solution. On the other hand, the base catalyzes the condensation reaction between the hydrolyzed silane compound and a functional group on the surface of the metal oxide particle, such as a hydroxyl group or a silanol group. These reactions make it easier for silane compounds such as silane compounds to adhere to the metal oxide particles in the dispersion step (step C) described below, improving the dispersion stability of the metal oxide particles.

Here, the above-mentioned "acid" refers to an acid based on the so-called Brønsted-Lowry definition, and refers to a substance that provides protons in the hydrolysis reaction of a surface modification material such as a silane compound. Furthermore, the above-mentioned "base" refers to a base based on the so-called Brønsted-Lowry definition, and here refers to a substance that accepts protons in the hydrolysis reaction and subsequent condensation reaction of surface modification materials such as silane compounds. .

The acid is not particularly limited and can be arbitrarily selected as long as it can supply protons in the hydrolysis reaction of the silane compound. Examples of the acid include inorganic acids such as hydrochloric acid, hydrobromic acid, hydroiodic acid, sulfuric acid, nitric acid, boric acid, and phosphoric acid, and organic acids such as acetic acid, citric acid, and formic acid. These acids may be used alone or in combination of two or more.

The base is not particularly limited as long as it can accept protons in the hydrolysis reaction of the silane compound, and can be arbitrarily selected. Examples of the base include sodium hydroxide, potassium hydroxide, barium hydroxide, calcium hydroxide, ammonia, and amines. These bases may be used alone or in combination of two or more.

Among those mentioned above, it is preferable to use an acid as the catalyst. From the viewpoint of acidity, the acid is preferably an inorganic acid, and more preferably hydrochloric acid.

The content of the catalyst in the hydrolysis solution is not particularly limited, but 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 even more preferably 30 ppm or more and 600 ppm or less. Thereby, side reactions of the silane compound can be suppressed while sufficiently promoting hydrolysis of the silane compound. Note that, if necessary, the content of the catalyst in the hydrolysis liquid may be 0.1 ppm or more and 100 ppm or less, or 1 ppm or more and 10 ppm or less. Further, for example, when an acid such as hydrochloric acid (1N) is used as a catalyst, the amount of the acid may be 0.001 parts by mass or more and 5 parts by mass or less based on 100 parts by mass in the hydrolyzate. , may be 0.001 parts by mass or more and 3 parts by mass or less, 0.005 parts by mass or more and 1 part by mass or less, 0.005 parts by mass or more and 0.1 parts by mass or less. .

Moreover, the hydrolyzate may contain a hydrophilic solvent as necessary. The hydrophilic solvent can promote the miscibility of water and the silane compound in the hydrolysis solution, and can further promote the hydrolysis reaction of the silane compound.

Examples of such hydrophilic solvents include various hydrophilic solvents that can be included in the above-mentioned dispersion. The content of the hydrophilic solvent in the hydrolysis liquid may be 0% by mass or more and 85% by mass or less, or 10% by mass or more and 70% by mass or less.

Among the above, the hydrophilic solvent preferably contains at least one selected from the group consisting of alcohol solvents, and more preferably, from the viewpoint of having excellent affinity with water and hydrophobic solvents and promoting their mixing. contains at least one selected from the group consisting of methanol and ethanol.

Further, the content of the hydrophilic solvent in the hydrolysis solution is not particularly limited, but for example, it is preferably 85% by mass or less, more preferably 80% by mass or less, and 75% by mass or less. is even more preferable. Within this range, the contents of the silane compound and water in the hydrolysis solution can be sufficiently increased.
The content of the hydrophilic solvent in the hydrolysis liquid may be 40% by mass or less, or 20% by mass or less. 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. Within this range, the mixing of the silane compound and water can be further promoted, and as a result, the hydrolysis reaction of the silane compound can proceed efficiently. Note that the hydrolysis solution may not contain any hydrophilic solvent other than the compound derived from the hydrolysis reaction. That is, only a hydrophilic solvent, which is a compound derived from a hydrolysis reaction, may be included.

In this embodiment, when a silane compound having an alkoxy group is used as the silane compound, since this is hydrolyzed, an alcohol compound derived from the alkoxy group will be contained in the mixed liquid. Since the hydrolysis reaction also proceeds with water adsorbed by metal oxide particles, it can occur in any of Steps A to E. Therefore, in this case, unless there is a step to remove the alcohol compound, the resulting dispersion will contain the alcohol compound. Therefore, a step of removing these alcohol compounds using an evaporator or the like may be provided as appropriate.

In the hydrolysis step, after preparing the hydrolysis solution, it may be maintained at an arbitrarily selected constant temperature for a predetermined period of time. Thereby, the hydrolysis of the silane compound can be further promoted.
In this treatment, the temperature of the hydrolyzed solution is not particularly limited and can be arbitrarily selected, and can be changed as appropriate depending on the type of silane compound. For example, the temperature is preferably 5°C or more and 65°C or less, more preferably 20°C or more and 65°C or less, and further preferably 30°C or more and 60°C or less. If necessary, the temperature may be 40°C or more and 75°C or less, or 50°C or more and 70°C or less.

Further, the holding time at the above temperature is not particularly limited, but 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. If necessary, the time may be 15 minutes or more and 60 minutes or less, or 20 minutes or more and 40 minutes or less.
In addition, in holding the above-mentioned hydrolyzed liquid, the hydrolyzed liquid may be appropriately stirred.

(Process B (mixing process))
In the mixing step, a silane compound and metal oxide particles are mixed to obtain a mixed solution. In the mixing step, water and a catalyst may be mixed in addition to the silane compound and metal oxide particles. In addition, when the hydrolysis liquid is obtained by the hydrolysis process mentioned above, a mixed liquid is obtained by mixing the hydrolysis liquid and metal oxide particles.

The content of metal oxide particles in the mixed liquid is 10% by mass or more and 49% by mass or less, and the total content of the silane compound and metal oxide particles is 65% by mass or more and 98% by mass or less. Mixing is then carried out.

Thus, in this embodiment, the total content of the silane compound and metal oxide particles in the mixed liquid is very large. Organic solvents and dispersion media such as water, which were conventionally thought to be essential, are either not included in the mixed liquid, or are mixed only in a very small amount compared to conventional methods. Alternatively, due to hydrolysis, a small amount of an unavoidable alcohol compound is contained. Even in such cases, by going through the dispersion process, it is possible to uniformly disperse the metal oxide particles in the mixed liquid, and also to ensure uniform adhesion of the silane compound to the metal oxide particles (surface modification). ) is achieved.

To explain in detail, generally when surface-modifying metal oxide particles with a silane compound in a liquid phase, a mixed solution is obtained by mixing not only the metal oxide particles and the silane compound but also a dispersion medium. It is common to perform dispersion processing using a dispersion machine. Furthermore, when metal oxide particles surface-modified in this way are mixed with methyl-based silicone resin, they cannot be sufficiently dispersed in the methyl-based silicone resin and aggregate. There was a problem that turbidity such as white clouding occurred. In such a case, the metal oxide particles added do not fully exhibit the desired performance.

The dispersion medium is usually added for the purpose of lowering the viscosity of the liquid mixture, uniformly dispersing the metal oxide particles, and uniformly modifying the surface of the metal oxide particles with the silane compound. Conventionally, it has been thought that when a dispersion medium is not used, the viscosity of the dispersion liquid increases, resulting in insufficient adhesion of the silane compound to the surface of the metal oxide particles. Surprisingly, the present inventors did not use such a dispersion medium, which was conventionally thought to be essential, or used only a small amount of it, and directly deposited metal oxide particles into a highly concentrated silane compound. It has been found that by dispersing the metal oxide particles, it is possible to achieve uniform dispersion of the metal oxide particles in the resulting dispersion, and it is also possible to uniformly modify the metal oxide particles with the silane compound.

The silane compound has a low molecular weight and a relatively low viscosity. Furthermore, since it is hydrolyzed in the above-mentioned hydrolysis step, it has good adhesion to metal oxide particles. Therefore, silane compounds are extremely suitable for dispersing metal oxide particles in highly concentrated surface-modified materials.

If the total content of the silane compound and metal oxide particles is less than 65% by mass, the amount of components other than the above two components, such as dispersion medium, will be too large, and therefore the silane compound will not be used in the dispersion step (step C) described below. The compound cannot be sufficiently attached to the surface of the metal oxide particles. As a result, many hydroxyl groups remain on the surface of the metal oxide particles, and when the resulting dispersion is mixed with a hydrophobic material, the metal oxide particles agglomerate, resulting in the formation of a hydrophobic material. This will cause turbidity. The total content of the silane compound and metal oxide particles may be 65% by mass or more, preferably 70% by mass or more, and more preferably 75% by mass or more. The total content of the silane compound and metal oxide particles may be 80% by mass or more, 85% by mass or more, 90% by mass or more, or 92% by mass or more, if necessary.

On the other hand, if the total content of the silane compound and metal oxide particles exceeds 98% by mass, the viscosity of the mixed liquid becomes too high, and the silane compound is not sufficiently contained in the dispersion step (step C) described below. cannot be attached to the surface of metal oxide particles. The total content of the silane compound and metal oxide particles may be 98% by mass or less, preferably 97% by mass or less, and more preferably 95% by mass or less. The total content of the silane compound and metal oxide particles may be 90% by mass or less, 85% by mass or less, 80% by mass or less, or 75% by mass or less, if necessary.

Further, as described above, the content of metal oxide particles in the mixed liquid is 10% by mass or more and 49% by mass or less. This range allows the amount of silane compound relative to the metal oxide particles to be within an appropriate range, allowing the silane compound to adhere uniformly to the surface of the metal oxide particles, and preventing an increase in the viscosity of the mixed liquid. Can be suppressed.

On the other hand, when the content of metal oxide particles in the mixed liquid is less than 10% by mass, the amount of silane compound becomes excessive with respect to the metal oxide particles, and the excess silane compound becomes metal oxide in the resulting dispersion. Induces particle agglomeration. The content of metal oxide particles in the mixed liquid is preferably 20% by mass or more, more preferably 23% by mass or more, even more preferably 26% by mass or more, particularly preferably 30% by mass or more. It is.

Moreover, when the content of the metal oxide particles exceeds 49% by mass, the amount of the silane compound is insufficient relative to the metal oxide particles, and a sufficient amount of the silane compound does not adhere to the metal oxide particles. Moreover, as a result of the content of metal oxide particles becoming too large, the viscosity of the liquid mixture becomes too large, and the metal oxide particles cannot be sufficiently dispersed in the dispersion step (step C) described below. The content of metal oxide particles in the liquid mixture is preferably 45% by mass or less, more preferably 40% by mass or less. The content of metal oxide particles in the liquid mixture is more preferably 38% by mass or less, particularly preferably 36% by mass or less. It may be 34% by mass or less.

The content of the silane compound relative to the content of metal oxide particles in the mixed liquid is not particularly limited, but is preferably, for example, 100% by mass or more and 800% by mass or less with respect to the amount of metal oxide particles. It is more preferably 140% by mass or more and 600% by mass or less, even more preferably 180% by mass or more and 400% by mass or less, and particularly preferably 200% by mass or more and 270% by mass or less. Thereby, the amount of the silane compound relative to the metal oxide particles can be kept within an appropriate range, and the silane compound can be uniformly attached to the surface of the metal oxide particles.

Further, in the mixing step, an organic solvent may be further mixed into the mixed liquid. By mixing an organic solvent into the liquid mixture, it becomes possible to control the reactivity of the surface modification material, and it becomes possible to control the degree of attachment of the surface modification material to the surface of the metal oxide particles. Furthermore, the organic solvent allows adjustment of the viscosity of the mixture.

Examples of such organic solvents include the hydrophobic solvents and hydrophilic solvents mentioned above as the dispersion medium of the composition of the present embodiment. These organic solvents may be used alone or in combination of two or more.

The content of the organic solvent in the mixed liquid is not particularly limited as long as the content of the metal oxide particles and the silane compound described above is satisfied. Note that it goes without saying that the mixed liquid does not need to contain an organic solvent.
The mixing time and mixing temperature in the mixing step can be selected arbitrarily, but for example, mixing may be performed at room temperature (25° C.), and after the materials are combined, stirring may be performed for about 0 to 600 seconds.

(Process C (dispersion process))
In the dispersion step, metal oxide particles are dispersed in the liquid mixture to obtain a first dispersion liquid in which metal oxide particles are dispersed. In this embodiment, metal oxide particles are dispersed in a highly concentrated hydrolyzed silane compound. Therefore, in the obtained first dispersion, the silane compound is relatively uniformly attached to the surface of the metal oxide particles, and the metal oxide particles are relatively uniformly dispersed.

The metal oxide particles can be dispersed using a known dispersion method, for example, using a dispersion machine. As the dispersing machine, for example, a bead mill, a ball mill, a homogenizer, a disperser, a stirrer, etc. are suitably used. Step C is preferably a step in which only the mixture obtained in Step B is subjected to a dispersion treatment.

In the dispersion process, the metal oxide particles in the dispersion are mixed by applying the minimum amount of energy without applying excessive energy so that the particle size (dispersed particle size) is almost uniform. It is preferable to disperse the metal oxide particles in the liquid.
The dispersion time can be arbitrarily selected depending on the conditions, but may be, for example, 3 hours to 20 hours, preferably 4 hours to 18 hours, more preferably 6 hours to 16 hours, and even more preferably is 8 to 14 hours. However, the dispersion time is not limited to these.
The dispersion temperature can be arbitrarily selected, but may be, for example, 10°C to 50°C, preferably 20°C to 40°C, and more preferably 30°C to 40°C. However, the dispersion temperature is not limited to these.
Note that the difference between the dispersion step C and the mixing step B may be that the dispersion is continuously performed over a certain period of time.

The scattering properties of the cured product at a wavelength of 450 nm and the scattering properties of the cured product at a wavelength of 600 nm can be controlled relatively easily by adjusting the dispersion conditions. If the scattering amount of the cured product at a wavelength of 450 nm is small, the dispersion time may be increased. On the other hand, if the amount of scattering of the cured product at a wavelength of 450 nm is large, the dispersion time may be shortened. If adjustment cannot be made using only the dispersion time, adjust the type and ratio of metal oxide particles and surface modification materials so that the amount of scattering at a wavelength of 450 nm of the above-mentioned cured product and the amount of scattering at a wavelength of 600 nm of the above-mentioned cured product are appropriate. do it. In particular, it is preferable to adjust the refractive index of the metal oxide particles.

(Step D (addition step (first addition step)))
In the addition step, a hydrophobic solvent is added to the first dispersion liquid obtained in Step C (dispersion step), and the first dispersion liquid is adjusted to a desired solid content concentration.
The first dispersion obtained in the dispersion step has a high solid content concentration. Therefore, the viscosity is high and the handling property is poor. However, if a hydrophobic solvent is simply added to the obtained first dispersion in order to lower the solid content concentration, the particles will aggregate due to the low hydrophobicity of the particle surface, resulting in a uniform dispersion. is not obtained.

Therefore, as a result of investigation, the present inventors found that it is possible to adjust the dispersion liquid to a low solid content concentration by heating the obtained first dispersion liquid and gradually adding a hydrophobic solvent. I found it. By doing this, you can get very good results.

The above mechanism is assumed to be as follows.
By heating the first dispersion liquid, polymerization of the silane compound attached to the metal oxide particles progresses, and the hydrophobicity of the particle surface improves. Note that even if the polymerization reaction of the silane compound progresses too much, the metal oxide particles will aggregate. Therefore, a hydrophobic solvent is gradually added to the first dispersion liquid in which the polymerization reaction is in progress. By performing such addition, the surface is gradually made hydrophobic while suppressing excessive polymerization reaction, and a hydrophobic solvent can be gradually mixed.

That is, a hydrophobic solvent is added in an amount that does not cause the metal oxide particles to aggregate, and the polymerization reaction of the silane compound is allowed to proceed to an extent that the silane compound is compatible with the added amount of the hydrophobic solvent. By this, a dispersion liquid having a desired solid content concentration can be obtained.

As mentioned above, the hydrophobic solvent may be added gradually to prevent the metal oxide particles from agglomerating. Therefore, the hydrophobic solvent may be added after heating the first dispersion obtained in the above dispersion step, or the first dispersion may be heated after adding the hydrophobic solvent, or Heating of the first dispersion and addition of the hydrophobic solvent may be performed simultaneously.
That is, to explain more specifically, the addition step may be a step d1 of heating the first dispersion and then adding the hydrophobic solvent at a rate that does not cause the metal oxide particles to aggregate. , step d2 of adding the hydrophobic solvent at a rate that does not cause the metal oxide particles to aggregate while heating the first dispersion, or adding the hydrophobic solvent to the metal oxide particles. The step d3 may include heating the first dispersion liquid after adding the oxide particles at a rate that does not cause agglomeration.

In addition, in step d1, when adding metal oxide particles, heating of the dispersion liquid may be continued or heating may be stopped. The temperature of the dispersion liquid may be constant, or the temperature of the dispersion liquid may be changing. Preferably, the temperature of the dispersion is maintained constant. In step d2, when adding the metal oxide particles, the temperature of the dispersion may be constant or the temperature of the dispersion may be changing.
The above hydrophobic solvent may be added continuously or intermittently in two or more portions. When adding intermittently, there is no limit to the number of times, but it can be added, for example, in 2 to 6 times or 3 to 5 times. When adding the hydrophobic solvent in multiple portions, the amount of the hydrophobic solvent may be the same or may be varied.

The speed at which the metal oxide particles do not aggregate is not particularly limited. The rate and ratio of addition of the hydrophobic solvent can be arbitrarily selected. For example, the hydrophobic solvent may be added continuously at such an addition rate that the solid content concentration is reduced in the range of 3% by mass or more and 20% by mass or less in 1 hour. In other words, after continuously adding the hydrophobic solvent for 1 hour, the difference in solid content concentration in the dispersion before and after addition may be in the range of 3% by mass or more and 20% by mass or less. The amount of hydrophobic solvent added may be adjusted as appropriate, such that when the heating temperature is high, the amount of hydrophobic solvent added is increased, and when the heating temperature is low, the amount of hydrophobic solvent added is decreased.

As mentioned above, the rate and ratio of addition of the hydrophobic solvent can be selected arbitrarily. For example, the hydrophobic solvent may be added stepwise every 30 minutes, every 1 hour, or every 2 hours so that the solid content concentration is reduced in the range of 3% by mass to 20% by mass. If the heating temperature is high, increase the amount of hydrophobic solvent added at one time, and if the heating temperature is low, reduce the amount of hydrophobic solvent added at one time. may be adjusted accordingly. In this case, the addition time and number of additions of the hydrophobic solvent may also be suitably adjusted.

The heating temperature is not particularly limited as long as it is a temperature at which the polymerization reaction of the silane compound proceeds. The heating temperature is preferably, for example, 35°C or higher and 80°C or lower. The heating temperature may be 40°C or more and 75°C or less, 45°C or more and 70°C or less, or 50°C or more and 65°C or less. By setting the heating temperature to 35° C. or higher, the polymerization reaction of the silane compound can proceed. On the other hand, by setting the heating temperature to 80° C. or lower, agglomeration of metal oxide particles due to rapid reaction of the silane compound can be suppressed.

The heating time may be maintained as appropriate until the adjustment of the solid content concentration is completed. The heating time is preferably, for example, 4 hours or more and 12 hours or less. When the heating time is 4 hours or more, the polymerization reaction of the silane compound progresses and it becomes possible to mix it with a hydrophobic solvent. On the other hand, by setting the heating time to 12 hours or less, agglomeration of metal oxide particles due to excessive progress of the polymerization reaction of the silane compound can be suppressed.

The hydrophobic solvent is not particularly limited as long as it is compatible with the material to be mixed with the dispersion of this embodiment. Examples of the hydrophobic solvent include aromatics, saturated hydrocarbons, unsaturated hydrocarbons, and the like. These hydrophobic solvents may be used alone or in combination of two or more. Among these, aromatics, particularly aromatic hydrocarbons, are preferred. Aromatics have excellent compatibility with methyl-based silicone resins, and thereby contribute to improving the viscosity characteristics of the resulting composition and improving the quality (transparency, shape, etc.) of the sealing member formed.

Examples of aromatic hydrocarbons include benzene, toluene, ethylbenzene, 1-phenylpropane, isopropylbenzene, n-butylbenzene, tert-butylbenzene, sec-butylbenzene, o-xylene, m-xylene, p-xylene, Examples include 2-ethyltoluene, 3-ethyltoluene, 4-ethyltoluene and the like. These aromatic hydrocarbons may be used alone or in combination of two or more.

Among these, aromatic hydrocarbons include toluene, o-xylene, m-xylene, At least one selected from the group consisting of p-xylene and benzene is particularly preferably used.

The content of the hydrophobic solvent contained in the final dispersion may be adjusted as appropriate so as to provide a desired solid content concentration. The content of the hydrophobic 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 60% by mass or more and 80% by mass or less. is even more preferable.
Through the first addition step, a second dispersion liquid having a desired solid content concentration is obtained. By using the second dispersion liquid, the handling properties of the dispersion liquid in the following steps are improved.

(Process F (removal process))
In this embodiment, a step F may be provided between step D and step E to remove alcohol produced by hydrolysis.
It is presumed that by providing the removal step, the production efficiency of the steps described below will be improved.
The removal method is not particularly limited, but for example, an evaporator can be used. The removal step may be performed until the alcohol is completely removed, or about 5% by mass may remain.

(Step E (second addition step))
The metal oxide particles are then treated with a silicone compound to obtain a third dispersion. As described above, in the dispersion step, the silane compound is relatively uniformly attached to the surface of the metal oxide particles. Therefore, the silicone compound can be relatively uniformly attached to the surface of the metal oxide particles via the silane compound.

In the second addition step, first, the second dispersion liquid and the silicone compound are mixed to obtain a treatment liquid. Then, the treatment liquid may be maintained at a constant temperature for a predetermined period of time. Thereby, adhesion of the silicone compound to the metal oxide particles can be further promoted.

Examples of the silicone compound include the silicone compounds mentioned above. These silicone compounds may be used alone or in combination of two or more.

The content of the silicone compound in the third dispersion is, for example, preferably 50% by mass or more and 500% by mass or less, more preferably 80% by mass or more and 400% by mass or less, based on the metal oxide particles. , more preferably 100% by mass or more and 300% by mass or less when mixed with the second dispersion liquid. This allows a sufficient amount of the silicone compound to adhere to the surface of the metal oxide particles, improving the dispersion stability of the metal oxide particles and improving the dispersibility in the methyl silicone resin. can. Furthermore, the amount of liberated silicone compounds can be reduced, and unwanted aggregation of metal oxide particles in the methyl silicone resin can be suppressed.

In the second addition step, the holding temperature is not particularly limited and can be changed as appropriate depending on the type of silicone compound, but for example, it is preferably 40°C or more and 130°C or less, and preferably 50°C or more and 120°C or less. More preferred.

Further, the holding time is not particularly limited, but for example, it is preferably 1 hour or more and 24 hours or less, and more preferably 2 hours or more and 20 hours or less.
In addition, in said holding|maintenance, the 2nd dispersion liquid may be stirred suitably.

Furthermore, in the second addition step, the treatment with the silicone compound may be performed multiple times. For example, by using different types of silicone compounds and performing the treatment with the silicone compound multiple times, it becomes easier to control the surface state of the metal oxide particles in accordance with the type of methyl silicone resin.
Further, in the second addition step, the solid content concentration may be measured after the treatment with the silicone compound, and the hydrophobic solvent may be added to obtain a desired solid content concentration. By lowering the solid content concentration, mixing with the resin component described later becomes easier.

As described above, metal oxide particles can be treated with a silicone compound to obtain a third dispersion liquid.

In the dispersion produced using the above production method, metal oxide particles are uniformly dispersed, and the surfaces of the metal oxide particles are uniformly and sufficiently modified with the silane compound and silicone compound. Metal oxide particles modified in this way with a refractive index of 1.7 or higher have excellent affinity with methyl silicone resins, and are compared in size to obtain the desired scattering properties in methyl silicone resins. can be uniformly dispersed. Therefore, even when metal oxide particles are dispersed in the methyl silicone resin, the brightness of the light emitting device can be improved when used as a sealing member.

In addition, the dispersion liquid of this embodiment may contain components other than those mentioned above, such as a dispersant, a dispersion aid, an antioxidant, a fluidity regulator, a thickener, a pH regulator, and a preservative, as necessary. General additives etc. may be mixed. These are added at any step as necessary.

(Composition)
The composition of this embodiment is a mixture of the above-described dispersion and a resin component. Therefore, the composition of the present embodiment includes metal oxide particles having a refractive index of 1.7 or more that are surface-modified with the above-mentioned silane compound and silicone compound, as well as a resin component, that is, at least one of a resin and a precursor thereof. including.

The composition of this embodiment is cured as described below and used as a sealing member for a light emitting device. The composition of this embodiment can improve the brightness of light from a light emitting device when used in a sealing member by containing the metal oxide particles that contribute to improving the refractive index and transparency described above. .

Further, the composition of the present embodiment includes metal oxide particles having a refractive index of 1.7 or more and whose surfaces are modified with the above-mentioned silane compound and silicone compound. Therefore, even when a methyl-based silicone resin is included as a resin component, excessive aggregation of metal oxide particles is suppressed, and a decrease in transparency is suppressed. Therefore, when the composition of this embodiment is used in a sealing member, the brightness of light from a light emitting device can be improved.

The content of metal oxide particles in the composition of the present embodiment is not particularly limited as long as the amount of scattering at a wavelength of 450 nm of the cured product and the amount of scattering at a wavelength of 600 nm of the cured product become desired values. For example, the content of the surface-modified metal oxide particles is preferably 2% by mass or more and 11% by mass or less, and 3% by mass or more with respect to the total content of the surface-modified metal oxide particles and the resin component. More preferably, it is 10% by mass or less.

Further, the content of surface modification materials such as silane compounds and silicone compounds in the composition of this embodiment can correspond to the content in the dispersion of this embodiment.

The average dispersed particle size of the surface-modified metal oxide particles in the composition of the present embodiment is not particularly limited as long as desired scattering properties are obtained, and may be, for example, from 30 nm to 1000 nm, and from 50 nm to 800 nm. or less, and may be 60 nm or more and 700 nm or less.
Further, the average dispersed particle size of the surface-modified metal oxide particles is not particularly limited as long as the particle size when cured as a sealing member is 60 nm or more and 1000 nm or less. Note that the average dispersed particle diameter when the composition is cured refers to the secondary particle diameter (aggregated particles) when the metal oxide particles are aggregated, that is, when they form secondary particles. diameter).
The state of aggregation of the surface-modified metal oxide particles in the cured product changes depending on the combination of the metal oxide particles, surface-modified material, resin component, and phosphor particles, and the curing conditions of the composition. Therefore, the average dispersed particle size of the metal oxide particles in the composition may be adjusted while checking the scattering characteristics at a wavelength of 450 nm and the scattering characteristics at a wavelength of 600 nm when the cured product is made. Examples of methods for adjusting the average dispersed particle size of metal oxide particles in the composition include a method for adjusting the average dispersed particle size of metal oxide particles in a dispersion.
The average dispersed particle diameter of the surface-modified metal oxide particles in the composition can be measured using, for example, a particle size distribution device.

(resin component)
The resin component is the main component in the composition of this embodiment. The resin component cures and seals the light emitting element when the composition of this embodiment is used as a sealing material. As a result, deterioration factors from the external environment, such as moisture and oxygen, are prevented from reaching the light emitting element. Furthermore, in this embodiment, the cured product obtained from the resin component is basically transparent and can transmit light emitted from the light emitting element.

Such a resin component is not particularly limited as long as it can be used as a sealing material. For example, resins such as silicone resins and epoxy resins may be used alone or in combination of two or more. As the silicone resin, phenyl silicone resin or methyl silicone resin can be used. From the viewpoint of durability, methyl silicone resin is particularly preferred.

The above-mentioned methyl silicone resin has, for example, a siloxane bond in which silicon and oxygen are alternately bonded as a main skeleton, and most of the functional groups bonded to Si atoms, for example, 60% or more, preferably 80% or more, are It may also mean a methyl group. However, the above-mentioned methyl silicone resin is not limited to this example.
As the methyl silicone resin, for example, dimethyl silicone resin, methylphenyl silicone resin, etc. can be used.

The content of the methyl silicone resin in the resin component may be adjusted depending on desired characteristics and is not particularly limited. For example, it may be 100% by mass, 20% by mass or more and 80% by mass or less, 30% by mass or more and 70% by mass or less, 40% by mass or more and 60% by mass or less. It's okay. Conventionally, when metal oxide particles were contained in a methyl silicone resin, the metal oxide particles agglomerated, resulting in decreased transparency and insufficient improvement in refractive index. Furthermore, even if the metal oxide particles were dispersed in the methyl silicone resin, it was difficult to completely suppress the occurrence of excessive agglomeration of the metal oxide particles. On the other hand, the composition of the present embodiment includes metal oxide particles having a refractive index of 1.7 or more and whose surfaces are modified with the above-mentioned silane compound and silicone compound. Therefore, even when such a large amount of methyl silicone resin is included as a resin component, aggregation of metal oxide particles is suppressed. Moreover, since it becomes possible to employ a methyl-based silicone resin, the durability of the sealing member formed using the composition is improved.

The structure of the resin component may be a two-dimensional chain structure, a three-dimensional network structure, or a cage structure.
The resin component may be in the form of a cured polymer when used as a sealing member. In the composition, the resin component may be in a state before curing, that is, a precursor. Thus, the resin component present in the composition may be, for example, a monomer, an oligomer, or a polymer.

The resin component may be of an addition reaction type, a condensation reaction type, or a radical polymerization reaction type.
The viscosity of the resin component at 25°C measured in accordance with JIS Z 8803:2011 is, for example, preferably 10 mPa·s or more and 100,000 mPa·s or less, and 100 mPa·s or more and 10,000 mPa·s or less. It is more preferable that it is, and even more preferably that it is 1,000 mPa·s or more and 7,000 mPa·s or less.

Further, the content of the resin component in the composition of the present embodiment can be the remainder of other components, but is preferably 10% by mass or more and 98% by mass or less, and 15% by mass or more and 97% by mass. It is more preferable that it is less than % by mass. The content of the resin component may be 30% by mass or more, 50% by mass or more, or 60% by mass or more. The content of the resin component may be 90% by mass or less, 80% by mass or less, or 70% by mass or less.

The composition of this embodiment may contain the dispersion medium derived from the dispersion according to this embodiment, or may be removed. That is, the dispersion medium derived from the dispersion liquid may be completely removed. The dispersion medium may remain in the composition in an amount of approximately 1% by mass or more and 10% by mass or less, or approximately 2% by mass or more and not more than 5% by mass.

Further, the composition of the present embodiment may contain phosphor particles within a range that does not impede the object of the present invention. The phosphor particles absorb light of a specific wavelength emitted from the light emitting element and emit light of a predetermined wavelength. That is, the phosphor particles make it possible to convert the wavelength of light and, in turn, adjust the color tone.

The phosphor particles are not particularly limited and can be arbitrarily selected as long as they can be used in a light-emitting device as described below, and can be appropriately selected and used so that the emitted light color of the light-emitting device becomes a desired color. can.
The content of phosphor particles in the composition of this embodiment can be adjusted as appropriate so as to obtain desired brightness.

In addition, the composition of this embodiment contains commonly used additives such as preservatives, polymerization initiators, polymerization inhibitors, curing catalysts, and light diffusing agents, to the extent that they do not impede the purpose of the present invention. may have been done. As the light diffusing agent, it is preferable to use silica particles having an average particle diameter of 1 μm to 30 μm.

The composition of this embodiment can be manufactured by mixing the dispersion of this embodiment and a resin component. Further, after mixing, the dispersion medium contained in the dispersion liquid may be removed using an evaporator or the like, if necessary.

The composition of this embodiment includes metal oxide particles having a refractive index of 1.7 or more and whose surfaces are modified with the above-mentioned silane compound and silicone compound. As a result, even when a methyl-based silicone resin is included as a resin component, aggregation of metal oxide particles is suppressed, and even if agglomerated, a decrease in transparency is suppressed. Therefore, the composition according to this embodiment can be used to form a sealing member that improves the brightness of light from a light-emitting device.

According to the composition of the present embodiment, the metal oxide particles whose surface has been densely modified with the surface modification material have the desired scattering content at a wavelength of 450 nm of the cured product and scattering content at a wavelength of 600 nm from the cured product. It is dispersed in the resin component so as to have a certain value. Therefore, if the composition of this embodiment is cured and used as a sealing member for a light emitting element, the brightness of the light emitting device can be improved.

(Method for producing composition)
The method for producing the composition of this embodiment is not particularly limited as long as the dispersion obtained in the above step and the resin component can be mixed.
Further, a step of removing the hydrophobic solvent from the obtained composition using an evaporator or the like may be provided.
Further, materials commonly included in sealing members, such as phosphor particles, may be mixed as appropriate.

(Sealing member)
The sealing member of this embodiment is a cured product of the composition of this embodiment. The sealing member of this embodiment is normally used as a sealing member placed on a light emitting element or as a part thereof.
The thickness and shape of the sealing member of this embodiment can be adjusted as appropriate depending on the desired use and characteristics, and are not particularly limited.

The sealing member of this embodiment can be manufactured by curing the composition of this embodiment as described above. The method for curing the composition can be selected depending on the characteristics of the resin component in the composition of this embodiment. Examples of methods for curing the composition include thermosetting and electron beam curing. More specifically, the sealing member of this embodiment can be obtained by curing the resin component in the composition of this embodiment by addition reaction or polymerization reaction.

The dispersed particle size of the surface-modified metal oxide particles in the sealing member is not particularly limited as long as the scattering amount of the cured product at a wavelength of 450 nm and the scattering amount of the cured product at a wavelength of 600 nm are desired values. The dispersed particle diameter of the surface-modified metal oxide particles in the sealing member may be, for example, 30 nm or more and 1000 nm or less, 40 nm or more and 900 nm or less, or 50 nm or more and 800 nm or less, The thickness may be 60 nm or more and 700 nm or less. The dispersed particle diameter of the surface-modified metal oxide particles herein means the secondary particle diameter (agglomerated particle diameter) when the particles are aggregated.
The dispersed particle diameter of the surface-modified metal oxide particles in the sealing member can be measured by observing a sample obtained by cutting the cured product into thin pieces using an electron microscope. However, since it is difficult to observe all the surface-modified metal oxide particles in the sealing member, it is difficult to uniquely define the particle size of the surface-modified metal oxide particles in the sealing member. . Further, even if the particle diameters are approximately the same, the light transmittance will differ if the degree of aggregation of the particles differs. Therefore, it is difficult to accurately measure the dispersed particle diameter of the surface-modified metal oxide particles in the sealing member. Therefore, it is difficult to specify the characteristics of the sealing member of this embodiment based on the dispersed particle diameter of the surface-modified metal oxide particles.

Since the sealing member of this embodiment is a cured product of the composition of this embodiment, it has excellent light scattering properties and transparency. Therefore, according to this embodiment, it is possible to obtain a sealing member that improves the brightness of light from a light emitting device.

(Light emitting device)
The light emitting device of this embodiment includes the above-described sealing member and a light emitting element sealed in the sealing member.

Examples of the light emitting element include a light emitting diode (LED), an organic light emitting diode (OLED), and the like. In particular, the sealing member of this embodiment is suitable for sealing a light emitting diode. The light emitting device of this embodiment is preferably a white LED light emitting device using a blue LED chip.

Hereinafter, the light emitting device of this embodiment will be described using an example in which the light emitting element is a light emitting diode on a chip, that is, an LED chip, and the light emitting device is an LED package.
1 to 4 are schematic diagrams (cross-sectional views) showing an example of the light emitting device of this embodiment, respectively.
Note that the size of each member in the drawings is appropriately emphasized for ease of explanation, and does not indicate actual dimensions or ratios between members. Note that, in this specification and the drawings, components having substantially the same functional configurations are designated by the same reference numerals and redundant explanation will be omitted.

The light emitting device (LED package) 1A shown in FIG. A sealing member 4A is provided for sealing.
The sealing member 4A is constituted by the sealing member of this embodiment described above. Therefore, the metal oxide particles derived from the composition of the present embodiment described above are dispersed in the sealing member 4A, and as a result, the light extraction efficiency in the light emitting device 1A is improved. Furthermore, phosphor particles 5 are dispersed within the sealing member 4A. The phosphor particles 5 convert the wavelength of at least a portion of the light emitted from the light emitting element 3.

The light emitting device 1B shown in FIG. 2 differs from the light emitting device 1A in that the sealing member 4B has two layers. That is, the sealing member 4B has a first layer 41B that directly covers the light emitting element 3, and a second layer 43B that covers the first layer 41B. Both the first layer 41B and the second layer 43B are the sealing members of this embodiment. Fluorescent particles 5 are dispersed within the first layer 41B. On the other hand, the second layer 43B does not contain the phosphor particles 5. In the light emitting device 1B, the metal oxide particles derived from the composition of the present embodiment described above are dispersed in the first layer 41B and the second layer 43B constituting the sealing member 4B. Brightness has improved.

The light emitting device 1C shown in FIG. 3 also differs from the light emitting device 1A in that the configuration 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 of this embodiment, but is a resin sealing member that does not contain the metal oxide particles described above, and is made of a resin or the like that can be used for the sealing member. Furthermore, the phosphor particles 5 are dispersed within the first layer 41C. On the other hand, the second layer 43C is the sealing member of this embodiment. In the light emitting device 1C, the metal oxide particles derived from the composition of the present embodiment described above are dispersed in the second layer 43C constituting the sealing member 4C, so that the light extraction efficiency is improved. There is.

In the light emitting device 1D shown in FIG. 4, the sealing member 4D includes a first layer 41D that directly covers the light emitting element 3, a second layer 43D that covers the first layer 41D, and a second layer 43D that further covers the second layer 43D. It has a third layer 45D. The first layer 41D and the second layer 43D are not the sealing member of this embodiment, but are resin sealing members that do not contain the metal oxide particles mentioned above, and are resins etc. that can be used for the sealing member. It is made up of. Further, within the second layer 43D, phosphor particles 5 are dispersed. On the other hand, the third layer 45D is the sealing member of this embodiment. In the light emitting device 1D, the brightness of light is improved by dispersing the metal oxide particles derived from the composition of the present embodiment described above in the third layer 45D constituting the sealing member 4D. There is.

Note that the light emitting device of this embodiment is not limited to the illustrated mode. For example, the light emitting device of this embodiment does not need to include phosphor particles in the sealing member. Moreover, the sealing member of this embodiment can exist at any position in the sealing member.

As described above, in the light emitting device of this embodiment, since the light emitting element is sealed with the sealing member of this embodiment, the brightness of light is improved.

Further, in the light-emitting device of this embodiment, the light-emitting element is sealed with the composition of this embodiment as described above. Therefore, in one aspect, the present invention also relates to a method for manufacturing a light-emitting device, which includes a step of sealing a light-emitting element using the composition of the present embodiment. In the same aspect, the manufacturing method may include a step of mixing the dispersion of the present embodiment and a resin component to obtain the composition.

Note that the light emitting element can be sealed by, for example, applying the composition of this embodiment onto the light emitting element using a dispenser or the like, and then curing the composition.

(Lighting equipment, display devices)
The light emitting device of this embodiment as described above can be used, for example, in lighting equipment and display devices. Therefore, in one aspect, the present invention relates to a lighting fixture or a display device including the light emitting device of this embodiment.
Examples of lighting equipment include general lighting devices such as indoor lights and outdoor lights, and lighting for switch sections of electronic devices such as mobile phones and office automation equipment.
Since the lighting equipment of this embodiment includes the light emitting device of this embodiment, even if the same light emitting element is used, the luminous flux emitted is larger than that of the conventional lighting equipment, and the surrounding environment can be made brighter.

Examples of display devices include mobile phones, personal digital assistants, electronic dictionaries, digital cameras, computers, televisions, and peripheral devices thereof.
Since the display device of this embodiment includes the light emitting device of this embodiment, even if the same light emitting element is used, the luminous flux emitted is larger than that of a conventional display device, so that, for example, a clearer and brighter display can be achieved. be able to.

Hereinafter, the present invention will be explained in more detail with reference to Examples and Comparative Examples. Note that the embodiments described below are merely examples of the present invention, and do not limit the present invention.

[Example 1]
(i) Hydrolysis step: 90.78 parts by mass of methyltriethoxysilane (product name: KBE-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). Prepared. These were added to a container and mixed to obtain a hydrolyzed solution. Next, this hydrolyzed solution was stirred at 60° C. for 30 minutes to perform a hydrolyzing treatment of methyltriethoxysilane to obtain a hydrolyzed solution.
47.92 parts by mass of propyltriethoxysilane (product name: KBE-3033, manufactured by Shin-Etsu Chemical Co., Ltd.), 4.15 parts by mass of water, 0.02 parts by mass of hydrochloric acid (1N), and 47.92 parts by mass of methanol. I prepared this. These were added to a container and mixed to obtain a hydrolyzed solution. This hydrolyzed solution was stirred at 60° C. for 1 hour, and propyltriethoxysilane was hydrolyzed to obtain a hydrolyzed solution.

(ii) Mixing step (Step B)
Mix 30 g of zirconium oxide particles (manufactured by Sumitomo Osaka Cement Co., Ltd.) with an average primary particle diameter of 12 nm, 77.1 g of a hydrolyzed solution of methyltriethoxysilane, and 32.6 g of a hydrolyzed solution of propyltriethoxysilane, A mixed solution was obtained. That is, zirconium oxide particles, methyltriethoxysilane, and propyltriethoxysilane were mixed in a mass ratio of 30:49:21.
The content of zirconium oxide particles in the mixed liquid is 21.5% by mass, the total content of methyltriethoxysilane and propyltriethoxysilane is 71.6% by mass, and the content of zirconium oxide particles, methyltrimethoxysilane, and propyltriethoxysilane is 71.6% by mass. The total content with silane was 93.1% by mass.

(iii) Dispersion step (Step C)
After dispersing this mixed solution in a bead mill for 11 hours, the beads were removed to obtain a first dispersion.

(iv) First addition step (step D)
The obtained first dispersion was heated at 60° C. for 2 hours. Next, toluene was added to the dispersion so that the solid content concentration was 40% by mass, and the mixture was heated at 60° C. for 2 hours.
Next, toluene was added to the dispersion so that the solid content concentration was 30% by mass, and the mixture was heated at 60° C. for 1 hour.
Next, toluene was added to the dispersion so that the solid content concentration was 20% by mass, and the mixture was heated at 60° C. for 1 hour to obtain a second dispersion.

(v) Second addition step (step E)
88.1 parts by mass of the second dispersion liquid whose solid content concentration was adjusted to 20% by mass with toluene and 11.9 parts by mass of methoxy group-containing phenyl silicone resin (trade name: KR217, manufactured by Shin-Etsu Chemical Co., Ltd.). After mixing to obtain a treatment liquid, this treatment liquid was heated at 110° C. for 1 hour to obtain a dispersion (third dispersion).
Next, toluene was mixed with the obtained dispersion to obtain the dispersion of Example 1 in which the solid content concentration was adjusted to 30% by mass.

(FT-IR analysis)
10 g of the dispersion of Example 1 whose solid content concentration was adjusted to 30% by mass with toluene was dried at 100°C and 20 hPa using a vacuum dryer (equipment name: VACUUM OVEN VOS-201SD, manufactured by EYELA Tokyo Rikakiki Co., Ltd.). It was dried under these conditions for 2 hours. Next, using 0.01 g to 0.05 g of the obtained metal oxide particles, a measurement of 800 cm ^-1 or more was performed using a Fourier transform infrared spectrophotometer (model number: FT/IR-670 Plus, manufactured by JASCO Corporation). The transmission spectrum in the wavenumber range of 3800 cm ⁻¹ or less was measured. The spectrum values were normalized so that the maximum value in this measurement range was 100 and the minimum value was 0, and based on this, the value at 3500 cm ^-1 (IA) and the value at 1100 cm ^-1 (IB) were determined. As a result, IA was 67.8, IB was 24.3, and IA/IB was 2.8. The results are shown in Table 1.

(Preparation of composition)
1.6 g of the dispersion of Example 1 and 15.1 g of methylphenyl silicone (trade name: KER-2500-B, manufactured by Shin-Etsu Chemical Co., Ltd.) were mixed. That is, the total mass of zirconium oxide particles and surface modification material and methylphenyl silicone were mixed in a mass ratio of 3:97.
Next, the composition of Example 1 was obtained by removing toluene from this mixed solution using an evaporator.

(Preparation of cured product)
The composition of Example 1 was filled into a 1 mm thick SUS container coated with Teflon (registered trademark) so that the film thickness was 1 mm. Next, after heating at 100°C for 2 hours, the cured product of Example 1 was obtained by heating at 150°C for 4 hours. The thickness of the cured product taken out from the container was 1 mm.

(light transmittance)
The linear transmittance and integral transmittance of the cured product of Example 1 taken out from the container at a wavelength of 450 nm and a wavelength of 600 nm were measured using a spectrophotometer (manufactured by JASCO Corporation, model number: V-770). Integrated transmittance means the result measured using an integrating sphere. The scattering component was calculated from the difference between the integrated transmittance and the linear transmittance. The results are shown in Table 1.

(Electron microscope observation)
A thin section of the cured product of Example 1 was used as a sample and observed with a field emission transmission electron microscope (trade name: JEM-2100F, manufactured by JEOL Ltd.). The results are shown in FIGS. 5 and 6. 5 and 6, in the cured product of Example 1, aggregated particles of about 400 nm were observed, but the aggregate particle diameter was about 200 nm to 600 nm.

(Production of LED package and evaluation of brightness)
The brightness of the LED package before being sealed with the composition of Example 1 was measured by photometry by applying a voltage of 3 V and a current of 150 mA to the LED package using a total luminous flux measurement system (manufactured by Otsuka Electronics Co., Ltd.). That is, the brightness A of the optical element itself was measured.

A composition in which 1 part by mass of the composition of Example 1 and 0.38 parts by mass of phosphor particles (yttrium aluminum garnet: YAG) were mixed (total amount of surface-modified aluminum oxide particles and resin: phosphor particles = 100 :38) was filled into the lead frame to a thickness of 300 μm. Thereafter, it was kept at room temperature for 3 hours. Next, the composition was slowly heated and cured to form the sealing member of Example 1, and the white LED package of Example 1 was produced.

The brightness B of the obtained white LED package of Example 1 was measured using a total luminous flux measurement system (manufactured by Otsuka Electronics Co., Ltd.) by applying a voltage of 3 V and a current of 150 mA to the LED package and performing photometry.
The improvement rate of the brightness B (lm) of the white LED package of Example 1 was calculated with respect to the brightness A (lm) of the optical element itself. The results are shown in Table 1.

[Comparative example 1]
(Preparation of dispersion)
(i) Hydrolysis step: 90.78 parts by mass of methyltriethoxysilane (product name: KBE-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). Prepared. These were added to a container and mixed to obtain a hydrolyzed solution. Next, this hydrolyzed solution was stirred at 60° C. for 30 minutes to perform a hydrolyzing treatment of methyltriethoxysilane to obtain a hydrolyzed solution.

(ii) Mixing step (Step B)
A mixed solution was obtained by mixing 30 parts by mass of zirconium oxide particles (manufactured by Sumitomo Osaka Cement Co., Ltd.) with an average primary particle diameter of 12 nm and 70 parts by mass of the above hydrolyzed solution.
The content of zirconium oxide particles in the mixed liquid was 30% by mass, the content of methyltriethoxysilane was 63.5% by mass, and the total content of zirconium oxide particles and methyltriethoxysilane was 93.5% by mass. Ta.

(iii) Dispersion step (Step C)
After dispersing this mixed solution in a bead mill for 6 hours, the beads were removed to obtain a first dispersion.

Steps were carried out in the same manner as in Example 1 except that the first dispersion obtained in Step C of Comparative Example 1 was used instead of the first dispersion obtained in Step C of Example 1. D and Step E were performed to obtain a dispersion liquid of Comparative Example 1 in which the solid content concentration was adjusted to 30% by mass.

In the same manner as in Example 1, the dispersion of Comparative Example 1 was analyzed by FT-IR. The results are shown in Table 1.

A composition of Comparative Example 1 and a cured product of Comparative Example 1 were obtained in the same manner as in Example 1 except that the dispersion of Comparative Example 1 was used instead of the dispersion of Example 1.
The light transmittance of the cured product of Comparative Example 1 was measured in the same manner as in Example 1. The results are shown in Table 1.

In the same manner as in Example 1, a sample obtained by cutting the cured product of Comparative Example 1 into thin sections was observed using an electron microscope. The results are shown in FIGS. 7 and 8. From FIGS. 7 and 8, it was confirmed that in the cured product of Comparative Example 1, many aggregated particles of 500 nm or more were formed.

An LED package of Comparative Example 1 was produced in the same manner as in Example 1 except that the composition of Comparative Example 1 was used instead of the composition of Example 1.
In the same manner as in Example 1, the brightness of the LED package before being sealed with the composition of Comparative Example 1 and the LED package of Comparative Example 1 was measured, and the brightness improvement rate of the LED package was calculated. The results are shown in Table 1. The LED package of Comparative Example 1 had lower brightness than the LED package before being sealed with the sealing member of Comparative Example 1.

[Comparative example 2]
A dispersion liquid of Comparative Example 2 was obtained in the same manner as Comparative Example 1 except that the dispersion time in the dispersion step (Step C) of Comparative Example 1 was changed to 11 hours.

In the same manner as in Example 1, the dispersion of Comparative Example 2 was analyzed by FT-IR. The results are shown in Table 1.

A composition of Comparative Example 2 and a cured product of Comparative Example 1 were obtained in the same manner as in Example 1 except that the dispersion of Comparative Example 2 was used instead of the dispersion of Example 1.
The light transmittance of the cured product of Comparative Example 2 was measured in the same manner as in Example 1. The results are shown in Table 1.

In the same manner as in Example 1, a sample obtained by cutting the cured product of Comparative Example 2 into thin sections was observed using an electron microscope. In the cured product of Comparative Example 1, aggregated particles of about 400 nm were observed as in Example 1, but the size of the aggregated particles was about 200 nm to 600 nm.

An LED package of Comparative Example 2 was produced in the same manner as in Example 1 except that the composition of Comparative Example 2 was used instead of the composition of Example 1.
In the same manner as in Example 1, the brightness of the LED package before being sealed with the composition of Comparative Example 2 and the LED package of Comparative Example 1 was measured, and the brightness improvement rate of the LED package was calculated. The results are shown in Table 1.

[Comparative example 3]
In the mixing step (Step B) of Comparative Example 1, 20 parts by mass of the above hydrolyzed liquid and 50 parts by mass of isopropyl alcohol (IPA) were used instead of mixing using 70 parts by mass of the above hydrolyzed liquid. In the same manner as in Comparative Example 1, a mixing step (Step B) and a dispersion step (Step C) were performed to obtain a dispersion liquid (first dispersion liquid).
The solid content concentration of the dispersion was measured (at 100° C. for 1 hour) and was found to be 38% by mass.

(iv) First addition step Toluene was added to the obtained dispersion (first dispersion) so that the solid content concentration was 20% by mass, and the mixture was heated at 60° C. for 2 hours. Next, toluene in the same amount as the volatilized amount was added to the dispersion, and the mixture was heated at 60° C. for 2 hours. Next, toluene in the same amount as the volatilized amount was added to the dispersion, and the mixture was heated at 60° C. for 1 hour. Next, toluene in the same amount as the volatilized amount was added to the dispersion, and the mixture was heated at 60° C. for 1 hour. By heating for 6 hours in this manner, surface modification was promoted and a dispersion liquid (second dispersion liquid) in which isopropyl alcohol was replaced with toluene was obtained.

(v) Second addition step 88.1 parts by mass of the second dispersion liquid whose solid content concentration was adjusted to 20% by mass and methoxy group-containing phenyl silicone resin (trade name: KR217, manufactured by Shin-Etsu Chemical Co., Ltd.) 11 .9 parts by mass were mixed to obtain a treatment liquid, and this treatment liquid was heated at 110° C. for 1 hour to obtain a dispersion liquid of Comparative Example 3 (third dispersion liquid).

FT-IR analysis was conducted in the same manner as in Example 1 for the dispersion of Comparative Example 3, in which the solid content concentration was adjusted to 30% by mass with toluene. As a result, IA was 42.1, IB was 10.0, and IA/IB was 4.2.

The dispersion of Comparative Example 1 whose solid content concentration was adjusted to 30% by mass with toluene was mixed with methylphenyl silicone in the same manner as in Example 1, and the toluene was removed to obtain a composition of Comparative Example 3. As a result, the composition of Comparative Example 3 became cloudy, and a composition capable of sealing an LED could not be obtained.

By comparing Example 1 and Comparative Example 1, it was found that metal oxide particles with a refractive index of 1.7 or more were densified with a methyl group-containing silane compound and a hydrocarbon group-containing silane compound having 2 or more and 5 or less carbon atoms. It was confirmed that the LED package produced using the dispersion containing the treated surface-modified metal oxide particles had improved brightness.
Furthermore, by comparing Example 1 and Comparative Example 2, it was found that even if the agglomerated particle diameters in the methyl silicone resin were the same when observed under a microscope, the silane compound containing a hydrocarbon group having 2 or more and 5 or less carbon atoms. It was confirmed that the brightness of the LED package was further improved by using .

Although preferred embodiments of the present invention have been described above in detail with reference to the accompanying drawings, the present invention is not limited to such examples. It is obvious that a person with ordinary knowledge in the technical field to which the present invention pertains can come up with various changes or modifications within the scope of the technical idea stated in the claims. It is understood that these also naturally fall within the technical scope of the present invention.

1A, 1B, 1C, 1D Light emitting device 2 Substrate 2a Upper substrate 2b Lower substrate 21 Recess 21a Bottom of recess 3 Light emitting elements 4A, 4B, 4C, 4D Sealing members 41B, 41C, 41D First layer 43B, 43C, 43D Second layer 45D Third layer 5 Phosphor particles

Claims (7)

A dispersion containing metal oxide particles whose surface has been modified with a surface modification material and has a refractive index of 1.7 or more, and a hydrophobic solvent,
The surface modification material includes a silane compound and a silicone compound,
The silane compound includes a methyl group-containing silane compound and a hydrocarbon group-containing silane compound having 2 or more and 5 or less carbon atoms,
The transmission spectrum of the metal oxide particles obtained by drying the dispersion liquid by vacuum drying was measured using a Fourier transform infrared spectrophotometer in a wave number range of 800 cm ^-1 to 3800 cm ^-1 , and , a dispersion liquid that satisfies the following formula (1) when the spectrum values are normalized so that the maximum value is 100 and the minimum value is 0.
IA/IB≦4.0 (1)
(In the formula, "IA" indicates the spectral value at 3500 cm ^-1 , and "IB" indicates the spectral value at 1100 cm ^-1 .) A composition which is a mixture of the dispersion according to claim 1 and a resin component. A sealing member which is a cured product of the composition according to claim 2. A light-emitting device comprising the sealing member according to claim 3 and a light-emitting element sealed by the sealing member. A lighting fixture comprising the light emitting device according to claim 4. A display device comprising the light emitting device according to claim 4. A method for producing the dispersion according to claim 1, comprising:
Step B of mixing a silane compound and metal oxide particles having a refractive index of 1.7 or more to obtain a mixed liquid;
Step C of dispersing the metal oxide particles in the mixed liquid to obtain a first dispersion liquid in which the metal oxide particles are dispersed;
Step D of adding a hydrophobic solvent to the first dispersion to obtain a second dispersion;
a step E of adding a silicone compound to the second dispersion to obtain a third dispersion;
The silane compound includes a methyl group-containing silane compound and a hydrocarbon group-containing silane compound having 2 or more and 5 or less carbon atoms,
In the step B, the content of the metal oxide particles in the mixed liquid is 10% by mass or more and 49% by mass or less, and the total content of the silane compound and the metal oxide particles in the mixed liquid is is 65% by mass or more and 98% by mass or less,
The step D includes heating the first dispersion liquid and then adding the hydrophobic solvent at a rate that does not cause the metal oxide particles to aggregate. Step d1 is adding the hydrophobic solvent while heating the first dispersion liquid. Either step d2 of adding the hydrophobic solvent at a rate that does not cause the metal oxide particles to aggregate, or step d3 of heating the first dispersion after adding the hydrophobic solvent at a rate that does not cause the metal oxide particles to aggregate. A method for producing a dispersion liquid.

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