JP2021155248A - Dispersion liquid, composition, sealing member, light-emitting device, lighting device, display device, and method for producing dispersion liquid - Google Patents

Abstract

To provide a dispersion liquid which contains metal oxide particles and suppresses aggregation of the metal oxide particles when being dispersed in a methyl silicone resin, a composition containing the same, a sealing member formed using the composition, a light-emitting device having the sealing member, a lighting device and a display device including the light-emitting device, and a method for producing a dispersion liquid.SOLUTION: A dispersion liquid contains metal oxide particles surface-modified with a silane compound and a silicone compound, in which when a transmission spectrum at a wave number of 800 cm-1 or more and 3,800 cm-1 or less for the metal oxide particles obtained by vacuum drying the dispersion liquid is measured by a Fourier transform infrared spectrophotometer, the transmission spectrum satisfies the following expression (1): IA/IB≤3.5. In the expression, IA represents a spectrum value of 3,500 cm-1, and IB represents a spectrum value of 1,100 cm-1.SELECTED DRAWING: Figure 1

Description

The present invention relates to a dispersion liquid containing metal oxide particles surface-modified with a silane compound and a silicone compound, a composition, a sealing member, a light emitting device, a lighting fixture, a display device, and a method for producing the dispersion liquid.

A light emitting diode (LED) is widely used as a light source having advantages such as small size, long life, and low voltage drive. The LED chip in the LED package is generally sealed with a sealing material containing a resin in order to prevent contact with deterioration factors existing 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 efficiently extract the light emitted from the LED chip to the outside of the LED package.

As a sealing material for improving the extraction efficiency of the light emitted from the LED chip, the surface was modified with a surface modifying material having one or more functional groups selected from an alkenyl group, an H—Si group, and an alkoxy group. A composition for forming a light scattering complex containing metal oxide particles and a matrix resin composition is known (for example, Patent Document 1).

In this composition for forming a light scattering complex, a dispersion liquid containing metal oxide particles having a small dispersed particle size and a high refractive index is mixed with the silicone resin in a state where the transparency is relatively maintained. As a result, the light scattering complex obtained by curing the composition for forming a light scattering complex has suppressed decrease in light transmittance and improved light scattering property.

International Publication No. 2016/142992

By the way, the present inventors not only improve the light scattering property of the obtained sealing member but also improve the refractive index of the sealing member by incorporating the metal oxide particles having a high refractive index into the sealing material. It was found that it can be made to. When the refractive index of the sealing member is improved, the efficiency of extracting light from the sealed light emitting element is generally improved. When the metal oxide particles are contained in the sealing material for such a purpose, it is advantageous that the content of the metal oxide particles is large from the viewpoint of improving the refractive index.

On the other hand, in recent years, in order to extend the life of LEDs, there is an increasing demand for a methyl silicone resin having high heat resistance as a sealing resin used as a sealing material. Methyl-based silicone resins have a higher content of methyl groups and a higher degree of hydrophobicity than phenyl silicone resins and the like that have been generally used in the past. Therefore, even if the metal oxide particles have a hydrophobic surface as in the invention described in Patent Document 1, when mixed with the methyl silicone resin, the metal oxide particles aggregate with each other and become transparent. There was a problem that a suitable composition could not be obtained. Such a problem becomes more remarkable as the content of the metal oxide particles in the sealing material increases.

The present invention has been made to solve the above problems, and is a dispersion liquid containing metal oxide particles and in which aggregation of the metal oxide particles is suppressed when dispersed in a methyl silicone resin. Provided are a composition containing the same, a sealing member formed by using the composition, a light emitting device having the sealing member, a lighting device and a display device provided with the light emitting device, and a method for producing a dispersion liquid. The purpose is.

In order to solve the above problems, one aspect of the present invention is a dispersion liquid containing metal oxide particles surface-modified with a surface-modifying material and a hydrophobic solvent.
The surface modification material contains a silane compound and a silicone compound, and contains
For the metal oxide particles obtained by drying the dispersion liquid by vacuum drying ^{, the transmission spectrum in the wave number range of 800 cm -1} or more and 3800 cm ^-1 or less is measured by a Fourier transform infrared spectrophotometer, and the transmission spectrum is measured in the range. When the spectrum values are standardized so that the maximum value of the spectrum is 100 and the minimum value is 0, the following equation (1):
IA / IB ≤ 3.5 (1)
(Wherein "IA", the spectral value at 3500 cm ^-1, "IB" respectively show the spectral values in the 1100 cm ^-1.)
Provide a dispersion liquid that satisfies the above.

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

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

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

In order to solve the above problems, one aspect of the present invention provides a luminaire provided with the above light emitting device.

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

In order to solve the above problems, one aspect of the present invention includes a step B of mixing a silane compound and metal oxide particles to obtain a mixed solution.
Step C of dispersing the metal oxide particles in the mixed solution to obtain a first dispersion in which the metal oxide particles are dispersed.
Step D to obtain a second dispersion by adding a hydrophobic solvent to the first dispersion,
Step E of adding a silicone compound to the second dispersion to obtain a third dispersion,
In step F, in which alcohol is added to the third dispersion and heated to obtain a fourth dispersion,
Have,
The content of the metal oxide particles in the mixed solution of the step B 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. Mass% or more and 98 mass% or less,
The step D of adding the hydrophobic solvent is a step d1 of adding the hydrophobic solvent at a rate at which the metal oxide particles do not aggregate after heating the first dispersion liquid, while heating the first dispersion liquid. , The step d2 of adding the hydrophobic solvent at a rate at which the metal oxide particles do not agglomerate, or after adding the hydrophobic solvent at a rate at which the metal oxide particles do not agglomerate, the first dispersion liquid is heated. A method for producing a dispersion liquid, which is step d3, is provided.

As described above, according to the present invention, a dispersion liquid containing metal oxide particles and in which aggregation of the metal oxide particles is suppressed when dispersed in a methyl silicone resin, a composition containing the dispersion, and the composition thereof. It is possible to provide a sealing member formed by using the sealing member, a light emitting device having the sealing member, a lighting device and a display device provided with the light emitting device, and a method for producing a dispersion liquid.

It is a schematic diagram which shows an example of the light emitting device which concerns on embodiment of this invention. It is a schematic diagram which shows another example of the light emitting device which concerns on embodiment of this invention. It is a schematic diagram which shows another example of the light emitting device which concerns on embodiment of this invention. It is a schematic diagram which shows another example of the light emitting device which concerns on embodiment of this invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.
<1. Ideas of the present inventors>
First, prior to the detailed description of the present invention, the ideas leading up to the present invention by the present inventors will be described.

Generally, in the production of a sealing material (composition) which is a raw material of a sealing member, metal oxide particles are modified by a surface modifying material and dispersed in a resin such as a silicone resin. However, the methyl silicone resin has a large content of methyl groups and a high degree of hydrophobicity as compared with a phenyl silicone resin or the like which has been generally used in the past. Therefore, even when the metal oxide particles are modified with the surface modifying material as described above, it is difficult for the metal oxide particles to be uniformly dispersed in the methyl silicone resin.

Therefore, as a result of diligent studies to solve the problem, the present inventors have not significantly improved the dispersibility of the metal oxide particles in the methyl silicone resin even if the amount of the surface modifying material used is simply increased. Was found.

Based on this result, the present inventors further investigated and focused on the modified state of the surface modifying material on the surface of the metal oxide particles. That is, even if the metal oxide particles are modified using a large amount of surface modifying material, if only a small amount of the surface modifying material adheres to the surface of the metal oxide particles, the surface of the metal oxide particles Is not sufficiently hydrophobic. On the other hand, even if the metal oxide particles are modified using a small amount of the surface modifying material, the adhesion ratio of the surface modifying material to the surface of the metal oxide particles is high, and a large amount is applied to the surface of the metal oxide particles. When a surface modifying material is attached to the metal oxide particles, the surface of the metal oxide particles is sufficiently hydrophobic.

Then, in the case where the silane compound and the silicone compound are used as the surface modifying material, the present inventors have determined the degree of adhesion of the surface modifying material to the metal oxide particles as described above by the Fourier transform infrared spectrophotometer (Fourier transform infrared spectrophotometer). It was found that the composition can be measured and observed by FT-IR), the silane compound and the silicone compound can be sufficiently adhered to the surface of the metal oxide particles by the method described later, and the composition is excellent in stability over time. ..

<2. Dispersion>
The dispersion liquid according to this embodiment will be described. The dispersion liquid according to the present embodiment contains metal oxide particles surface-modified with a silane compound and a silicone compound, and a hydrophobic solvent.

Then, in the present embodiment, the transmission spectrum of the metal oxide particles obtained by drying the dispersion liquid by vacuum drying in ^{the wave number range of 800 cm -1} or more and 3800 cm ^{-1 or less is obtained by a Fourier transform infrared spectrophotometer.} When the measurement was performed and the spectrum values were standardized so that the maximum value of the spectrum in the range was 100 and the minimum value was 0, the following equation (1):
IA / IB ≤ 3.5 (1)
(Wherein "IA", the spectral value at 3500 cm ^-1, "IB" respectively show the spectral values in the 1100 cm ^-1.)
To be satisfied.

As described above, when the dispersion liquid according to the present embodiment is mixed with the methyl silicone resin and the metal oxide particles are dispersed in the methyl silicone resin, the aggregation of the metal oxide particles is suppressed.
As a result, the composition (resin composition) obtained as a mixture suppresses turbidity and becomes relatively transparent.

More specifically, in the transmission spectrum measured by the Fourier transform infrared spectrophotometer ^{, the position of wave number 1100 cm -1} belongs to the siloxane bond (Si—O—Si bond), and the position of ^{wave number 3500 cm -1 is.} , Belongs to the silanol group (Si-OH group). The silane compound and the silicone compound each have a Si—OH group capable of forming a Si—O—Si bond and a group capable of forming a Si—OH group. Therefore, the spectral values (IA) in 3500 cm ^-1, by comparing the spectral values (IB) in 1100 cm ^-1, silane compound and Si-OH and the silicone compound, the Si-OH groups capable of forming group It becomes possible to observe the degree of reaction.

Then, the present inventors have found that the silane compound and the silicone compound are sufficiently adhered to the surface of the metal oxide particles when the IA / IB is 3.5 or less. As a result, the metal oxide particles can be dispersed in the methyl silicone resin without agglutination when mixed with the methyl silicone resin. As a result, the composition obtained as a mixture suppresses turbidity and becomes relatively transparent. Furthermore, since metal oxide particles are contained, when a sealing member for sealing the light emitting element is obtained using the composition, the refractive index of the sealing member is that of the methyl silicone resin alone. Compared to the one, it is improved. As described above, when a composition is obtained using the dispersion liquid according to the present embodiment and the light emitting element is sealed using the composition, the light emitting device is caused by the high refractive index and light transmittance of the sealing member. Brightness improves.

On the other hand, when the IA / IB exceeds 3.5, the silane compound and the silicone compound are not sufficiently adhered to the surface of the metal oxide particles, and the metal oxide particles are dispersed in the methyl silicone resin. It is not possible to make the sex excellent. As a result, when the dispersion liquid and the methyl silicone resin are mixed, agglutination of the metal oxide particles occurs, and the obtained composition becomes turbid. The IA / IB is 3.5 or less as described above, but is preferably 3.0 or less, more preferably 2.5 or less, and even more preferably 2.0 or less.

The lower limit of IA / IB is 0 because IA = 0 is preferable. However, even if a small amount of silanol group (Si-OH group) remains, it can be mixed with the methyl silicone resin, so the lower limit of IA / IB may be 0 or 0.1. It may be 0.5, 1.0, or 1.5.

Specifically, the measurement of the transmission spectrum of the metal oxide particles by the Fourier transform infrared spectrophotometer (FT-IR) can be performed as follows.
The dispersion liquid of this embodiment is dried by vacuum drying. The drying conditions may be appropriately adjusted according to the amount and concentration of the dispersion liquid. For example, if 10 g of the dispersion liquid has a solid content of 30% by mass, it 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 Science Instruments Co., Ltd. can be used.
Then, by using 0.01 g to 0.05 g of the metal oxide particles obtained by drying, a Fourier transform infrared spectrophotometer (for example, manufactured by Nippon Spectroscopy Co., Ltd., model number: FT / IR-670 Plus) is used. Can be measured.

Further, the finding that the IA / IB value for the metal oxide particles as described above has been achieved has not been obtained until now, and the present inventors have found that it can be achieved for the first time by the method described later.

The dispersion liquid of the present embodiment and methylphenyl silicone (methyl silicone resin) are mixed with the total mass of the metal oxide particles and the surface modifying material (silane compound and silicone compound) and the mass ratio of methylphenyl silicone to 30: It is preferable that the viscosity is 9 Pa · s or less when the mixture is mixed so as to be 70 and the hydrophobic solvent is removed.
Methylphenyl silicone is KER-2500-B manufactured by Shin-Etsu Chemical Co., Ltd.
The lower limit of the viscosity is the viscosity of KER-2500-B itself, but the viscosity may be, for example, 1 Pa · s or more, 2 Pa · s or more, or 3 Pa · s or more. You may.

The hydrophobic solvent is preferably completely removed by an evaporator or the like, but it is difficult to completely remove the hydrophobic solvent, so that about 5% by mass may remain.
The viscosity is measured using a rheometer (trade name: Leostress RS-6000, manufactured by HAAKE) under the conditions of 25 ° C. and a shear rate of 1 (1 / S).

When the hydrophobic solvent is removed, the particles are brought close to each other, and the viscosity of the composition (composition containing metal oxide particles, a surface modifying material, and a methyl silicone resin) is increased. Therefore, the viscosity when the hydrophobic solvent is removed means the viscosity of the composition measured within 1 hour after the hydrophobic solvent is removed from the dispersion liquid.

When the viscosity is 9 Pa · s or less, the viscosity of the composition increases slowly after the methylphenyl silicone and the dispersion liquid are mixed and the hydrophobic solvent is removed, so that the composition can be easily handled. The quality stability of the sealing member can be improved.

The dispersion liquid of the present embodiment and methylphenyl silicone are mixed so that the total mass of the metal oxide particles and the surface modifying material and the mass ratio of the methylphenyl silicone are 30:70, and the hydrophobic solvent is removed. It is preferable that the viscosity after one month has passed is 40 Pa · s or less.
If the viscosity after one month has passed is 40 Pa · s or less, the dehydration condensation reaction of the silane compound after the surface treatment is suppressed, the level is sufficiently tolerable for practical use, and it can be said that the stability over time is excellent. ..
The viscosity after one month is more preferably 35 Pa · s or less, and further preferably 30 Pa · s or less.

Hereinafter, each component contained in the dispersion liquid will be described.

(2.1 Metal oxide particles)
The metal oxide particles scatter the light emitted from the light emitting element in the sealing member described later. Further, the metal oxide particles improve the refractive index of the sealing member depending on the type. As a result, the metal oxide particles contribute to the improvement of the brightness of light in the light emitting device.

The metal oxide particles contained in the dispersion liquid according to the present embodiment are not particularly limited. In the present embodiment, the metal oxide particles include, for example, zirzyl oxide particles, titanium oxide particles, zinc oxide particles, iron oxide particles, copper oxide particles, tin oxide particles, cerium oxide particles, tanthal oxide particles, niobium oxide particles, and the like. Tungsten oxide particles, europium oxide particles, yttria oxide particles, molybdenum oxide particles, indium oxide particles, antimon oxide particles, germanium oxide particles, lead oxide particles, bismus oxide particles, and hafnium oxide particles, as well as potassium titanate particles and barium titanate particles. , Strontium titanate particles, potassium niobate particles, lithium niobate particles, calcium tantistate particles, yttria-stabilized zirconia particles, alumina-stabilized zirconia particles, calcia-stabilized zirconia particles, magnesia-stabilized zirconia particles, scandia-stabilized zirconia particles , Hafnia-stabilized zirconia particles, yttria-stabilized zirconia particles, ceria-stabilized zirconia particles, india-stabilized zirconia particles, strontium-stabilized zirconia particles, samarium oxide-stabilized zirconia particles, gadrinium oxide-stabilized zirconia particles, antimon-added tin oxide particles , And metal oxide particles containing at least one selected from the group consisting of yttria-stabilized tin oxide particles are preferably used.

Among the above, the dispersion liquid is at least one selected from the group consisting of zirconium oxide particles and titanium oxide particles from the viewpoint of improving transparency and compatibility (affinity) with the sealing resin (resin component). It is preferable to include it.
Further, the metal oxide particles preferably have a refractive index of 1.7 or more from the viewpoint of improving the refractive index of the sealing member.

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

The metal oxide particles may be dispersed as primary particles in the dispersion liquid, or may be dispersed as secondary particles in which the primary particles are aggregated. Usually, the metal oxide particles are dispersed as secondary particles.

The average dispersed particle size of the metal oxide particles in the dispersion is not particularly limited, but is, for example, 10 nm or more and 300 nm or less, preferably 20 nm or more and 250 nm or less, and more preferably 30 nm or more and 200 nm or less. When the average dispersed particle size of the metal oxide particles is 10 nm or more, the brightness of the light of the light emitting device manufactured by using this dispersion liquid, which will be described later, is improved. Further, when the average dispersed particle size of the metal oxide particles is 300 nm or less, it is possible to suppress a decrease in the light transmittance of the dispersion liquid, the composition described later, and the sealing member produced by using the dispersion liquid. .. As a result, the brightness of the light of the light emitting device is improved.

The average dispersed particle size of the metal oxide particles can be the particle size D50 of the metal oxide particles when the cumulative percentage of the scattering intensity distribution obtained by the dynamic light scattering method is 50%. It can be measured with a scattering type particle size distribution meter (for example, manufactured by HORIBA, model number: SZ-100SP). The measurement can be performed using a quartz cell having an optical path length of 10 mm × 10 mm for a dispersion liquid having a solid content adjusted to 5% by mass. In addition, in this specification, a "solid content" means a residue when a volatile component is removed in a dispersion liquid. For example, when 1.2 g of a dispersion liquid is placed in a magnetic crucible and heated on a hot plate at 100 ° C. for 1 hour, the components (metal oxide particles, surface modifying materials, etc.) that remain without volatilization are defined as solid contents. be able to.

Further, the average dispersed particle size of the metal oxide particles is the diameter of the dispersed metal oxide particles regardless of whether the metal oxide particles are dispersed in the primary particles or the secondary particles. Measured and calculated based on. Further, 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 modifying material is attached. Since metal oxide particles to which the surface-modifying material is attached and metal oxide particles to which the surface-modifying material is not attached may be present in the dispersion liquid, the average dispersed particle size of the metal oxide particles is usually set to be large. It is measured as a value in these mixed states.

The average primary particle size of the metal oxide particles is, for example, preferably 3 nm or more and 200 nm or less, more preferably 5 nm or more and 170 nm or less, and further preferably 10 nm or more and 100 nm or less. When the average primary particle size of the metal oxide particles is in the above range, it is possible to suppress a decrease in the transparency of the sealing member. As a result, the brightness of the light of the light emitting device can be further improved.

The average primary particle size of the metal oxide particles can be measured, for example, by observing with a transmission electron microscope. First, a transmission electron microscope image is obtained by observing a collodion film obtained by collecting metal oxide particles from a dispersion liquid with a transmission electron microscope. Next, a predetermined number, for example, 100 metal oxide particles in the transmission electron microscope image are selected. Then, the longest linear component (maximum major axis) of each of these metal oxide particles is measured, and these measured values are calculated by arithmetic mean.

Here, when the metal oxide particles are agglomerated with each other, the agglomerated particle size of the agglomerates is not measured. The maximum major axis of the metal oxide particles (primary particles) constituting this agglomerate is measured by a predetermined number and used as the average primary particle size.

Further, the content of the metal oxide particles in the dispersion liquid is not particularly limited as long as it can be mixed with the resin component described later. The content of the metal oxide particles in the dispersion is, for example, 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 10% by mass or more and 30% by mass or less. It is more preferably less than or equal to%.

As a result, it is possible to prevent the viscosity of the dispersion liquid from becoming excessively high, so that mixing with a resin component described later becomes easy. In addition, it is possible to prevent the amount of the solvent (dispersion medium) from becoming excessive after mixing with the resin component, and the solvent can be easily removed.

The surface modifying material described below is attached to the surface of the metal oxide particles described above. As a result, the metal oxide particles are stably dispersed in the dispersion liquid and the dispersion liquid produced by using the dispersion liquid.

(2.2 Surface modifier material)
The dispersion liquid according to the present embodiment contains a silane compound and a silicone compound as surface modifying materials. Only the silane compound and the silicone compound may be used as the surface modification material.
In the dispersion liquid, at least a part of the surface modifying material adheres to the surface of the metal oxide particles to modify the surface, thereby preventing the metal oxide particles from aggregating. Further, the compatibility with the resin component is improved.

Here, the term "adhering" to the metal oxide particles means that the surface-modifying material contacts or binds to the metal oxide particles by an interaction or reaction between them. Examples of the contact include physical adsorption. Further, examples of the bond include an ionic bond, a hydrogen bond, a covalent bond and the like.

The dispersion liquid according to the present embodiment contains at least a silane compound and a silicone compound as a surface modifying material. That is, in the present embodiment, the metal oxide particles are surface-modified with at least a silane compound and a silicone compound.

The silane compound tends to adhere to the vicinity of the surface of the 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 described later. By using such a silane compound and a silicone compound in combination, the dispersion stability of the metal oxide particles in the methyl silicone resin is improved.

On the other hand, when the dispersion liquid does not contain either a silane compound or a silicone compound, the above-mentioned effect cannot be obtained. For example, when the dispersion liquid does not contain a silane compound, the silicone compound is unlikely to adhere to the surface of the metal oxide particles, and the dispersibility of the metal oxide particles in the methyl silicone resin becomes inferior. On the other hand, when the dispersion liquid does not contain the silicone compound, the affinity between the metal oxide particles and the methyl silicone resin is not sufficiently increased, and the dispersibility of the metal oxide particles in the methyl silicone resin is inferior. Become.

Examples of the silane compound include methyltrimethoxysilane, methyltriethoxysilane, methyltripropoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, and ethyltripropoxysilane, isobutyltrimethoxysilane, methylphenyldimethoxysilane, and methylphenyl. Silane compounds containing alkyl and alkoxy groups such as diethoxysilane, silane compounds containing alkenyl and alkoxy groups such as vinyltrimethoxysilane, metharoxypropyltrimethoxysilane, and acryloxipropyltrimethoxysilane, diethoxymonomethylsilane, Silane compounds containing H-Si groups and alkoxy groups such as monoethoxydimethylsilane, diphenylmonomethoxysilane and diphenylmonoethoxysilane, silane compounds containing other alkoxy groups such as phenyltrimethoxysilane, and dimethylchlorosilane and methyldichlorosilane. Examples thereof include silane compounds containing an H-Si group such as diethylchlorosilane, ethyldichlorosilane, methylphenylchlorosilane, diphenylchlorosilane, phenyldichlorosilane, trimethoxysilane, dimethoxysilane, monomethoxysilane, and triethoxysilane. One of these silane compounds may be used alone, or two or more thereof may be used in combination. Among these, a silane compound having an alkoxy group, particularly a methoxy group, is preferable because it easily adheres to the metal oxide particles.

Among the above, the silane compound preferably contains a silane compound containing an alkyl group and an alkoxy group from the viewpoint of having a low viscosity and facilitating the dispersion of metal oxide particles in the dispersion step described later.
The number of alkoxy groups in the silane compound containing such an alkyl group and an alkoxy group is preferably 1 or more and 3 or less, and the number of alkoxy groups is more preferably 3. The alkoxy group preferably has 1 or more and 5 or less carbon atoms.
The number of alkyl groups in the silane compound containing an alkyl group and an alkoxy group is preferably 1 or more and 3 or less, and more preferably 1. The number of carbon atoms of the alkyl group is preferably 1 or more and 5 or less, more preferably 1 or more and 3 or less, and further preferably 1 or more and 2 or less.
The total number of alkoxy groups and alkyl groups in the silane compound containing an alkyl group and an alkoxy group is 2 or more and 4 or less, preferably 4.
The silane compound as such a surface modifying material is selected from the group consisting of, for example, methyltrimethoxysilane, methyltriethoxysilane, methyltripropoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, and ethyltripropoxysilane. Includes at least one species.

The content of the silane compound in the dispersion is not particularly limited, but is preferably 50% by mass or more and 500% by mass or less, and 70% by mass or more and 400% by mass or less, with respect to the metal oxide particles. More preferably, it is more preferably 90% by mass or more and 300% by mass or less. As a result, a sufficient amount of silicone compound can be attached to the surface of the metal oxide particles via the silane compound, improving the dispersion stability of the metal oxide particles and dispersibility in the methyl silicone resin. Can be improved.

Examples of the silicone compound include alkoxy group-containing phenyl silicone, dimethyl silicone, methylphenyl silicone, methylhydrogen silicone, methylphenylhydrogen silicone, diphenylhydrogen silicone, alkoxy double-ended phenyl silicone, alkoxy double-ended methylphenyl silicone, and alkoxy. Examples thereof include group-containing methylphenyl silicone, alkoxy group-containing dimethyl silicone, alkoxy one-terminal trimethyl one-terminal (methyl group 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 a monomer or an oligomer because surface modification is easy.

Among the above, from the viewpoint of ease of reaction and high hydrophobicity, the silicone compound is preferably an alkoxy group-containing phenyl silicone, a dimethyl silicone, a methyl phenyl silicone, an alkoxy double-ended phenyl silicone, an alkoxy double-ended methyl phenyl silicone, and the like. It contains at least one selected from the group consisting of an alkoxy group-containing methylphenyl silicone, an alkoxy group-containing dimethyl silicone, an alkoxy one-terminal trimethyl one-terminal (methyl group end) dimethyl silicone, and an alkoxy group-containing phenyl silicone, and more preferably methoxy. It contains at least one selected from the group consisting of group-containing phenyl silicone, dimethyl silicone, and methoxy group-containing dimethyl silicone.

The content of the silicone compound in the dispersion is not particularly limited, but is preferably 50% by mass or more and 500% by mass or less, and 80% by mass or more and 400% by mass or less, with respect to the metal oxide particles. More preferably, it is more preferably 100% by mass or more and 300% by mass or less. As a result, a sufficient amount of the silicone compound can be adhered to the surface of the metal oxide particles, the dispersion stability of the metal oxide particles can be improved, and the dispersibility in the methyl silicone resin can be improved. can. Further, the amount of the liberated silicone compound can be reduced, and the unintentional aggregation of the metal oxide particles in the methyl silicone resin can be suppressed.

Further, the dispersion liquid may contain components other than the silane compound and the silicone compound as the surface modifying material. Examples of such a component include carbon-carbon unsaturated bond-containing fatty acids, specifically, methacrylic acid, acrylic acid, and the like.

The amount of the surface modifying material with respect to the metal oxide particles, that is, the total content of the silane compound and the silicone compound is not particularly limited, and is preferably 100% by mass or more and 1000% by mass or less, and is preferably 150% by mass or more. It is more preferably 800% by mass or less, and further preferably 190% by mass or more and 600% by mass or less. When the amount of the surface modifying material is within the above range, the dispersibility of the metal oxide particles can be sufficiently improved while reducing the amount of the surface modifying material to be released.

(2.3 Hydrophobic solvent)
Further, the dispersion liquid according to the present embodiment contains a hydrophobic solvent for dispersing the metal oxide particles as a dispersion medium. The hydrophobic solvent is not particularly limited as long as it can disperse the metal oxide particles to which the surface modifying material is attached and can be mixed with the resin component described later.
Examples of such a 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 the above, the hydrophobic solvent is preferably an aromatic, particularly an aromatic hydrocarbon. Aromatic compounds have excellent compatibility with methyl silicone resins, which will be described later, and contribute to improving the viscosity characteristics of the resulting composition and improving the quality (transparency, shape, etc.) of the sealing member to be formed.

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

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

The content of the hydrophobic solvent contained in the dispersion may be appropriately adjusted so as to have a desired solid content. 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 later, particularly a methyl silicone resin.

The dispersion liquid of the present embodiment may contain a hydrophilic solvent. The hydrophilic solvent can be contained in the dispersion, for example, due to the methods described below. Examples of such a hydrophilic solvent 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 the alcohol solvent include branched or linear alcohol compounds having 1 to 4 carbon atoms and ether condensates thereof. These alcohol solvents may be used alone or in combination of two or more. The alcohol compound contained in the alcohol solvent may be any of a primary alcohol, a secondary alcohol and a tertiary alcohol. The alcohol compound contained in the alcohol solvent may be any of monohydric alcohol, dihydric alcohol and trihydric alcohol. More specifically, examples of the alcohol solvent include methanol, ethanol, 1-propanol, isopropyl alcohol, 1-butyl alcohol, 2-butanol, isobutyl alcohol, tert-butyl alcohol, methanediol, 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 thereof include 4-diol, 1,4-butanediol, glycerin, diethylene glycol, 3-methoxy-1,2-propanediol and the like.

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

The hydrophilic solvent preferably contains an alcohol-based solvent from the viewpoint of having excellent affinity with both water and the hydrophobic solvent and promoting their miscibility. In this case, the carbon number of the alcohol compound constituting the alcohol solvent is preferably 1 or more and 3 or less, and more preferably 1 or more and 2 or less.
Among the above, methanol and ethanol, particularly methanol, can be preferably used because the effects of the above alcohol-based solvent can be sufficiently exhibited.

The content of the hydrophilic solvent in the dispersion is, for example, preferably 10% by mass or less, more preferably 7% by mass or less, further preferably 5% by mass or less, and 3% by mass or less. Is particularly preferable. The content of the hydrophilic solvent may be 0% by mass.

(2.4 Other ingredients)
The dispersion liquid according to the present embodiment may contain components other than those described above. For example, the dispersion liquid according to the present embodiment may contain components other than those described above, such as a dispersant, a dispersion aid, an antioxidant, a flow regulator, a thickener, a pH regulator, and a preservative, if necessary. It may contain general additives and the like.
Further, the dispersion liquid according to the present embodiment may contain components that may be contained due to the method described later, for example, acid, water, alcohol and the like.

In the present specification, the dispersion liquid according to the present embodiment is distinguished from the composition according to the present embodiment, which contains a resin component and can form a sealing member by curing. That is, the dispersion liquid according to the present embodiment does not contain the resin component described later to the extent that a sealing member can be formed even if it is simply cured. More specifically, in the dispersion liquid according to the present embodiment, the mass ratio of the resin component and the metal oxide particles is in the range of 0: 100 to 40:60 for the resin component: metal oxide particles. It is preferably in the range of 0: 100 to 20:80, more preferably. The dispersion liquid according to the present embodiment is more preferably essentially free of the resin component described later, and particularly preferably completely free of the resin component described later.

In the dispersion liquid according to the present embodiment, the surface of the metal oxide particles is sufficiently modified with a silane compound and a silicone compound. The metal oxide particles modified in this way have excellent affinity with the methyl silicone resin and can be dispersed relatively uniformly in the methyl silicone resin. Therefore, even when the metal oxide particles are dispersed in the methyl silicone resin, the generation of turbidity such as white turbidity is suppressed. Furthermore, the change in viscosity of the methyl silicone resin containing the metal oxide particles is also suppressed.

<3. Dispersion liquid manufacturing method>
Next, a method for producing the dispersion liquid according to the present embodiment will be described.

The method for producing the dispersion liquid according to the present embodiment includes step B in which the silane compound and the metal oxide particles are mixed to obtain a mixed liquid.
Step C of dispersing the metal oxide particles in the mixed solution to obtain a first dispersion in which the metal oxide particles are dispersed.
Step D to obtain a second dispersion by adding a hydrophobic solvent to the first dispersion,
Step E of adding a silicone compound to the second dispersion to obtain a third dispersion, and step F of adding alcohol to the third dispersion and heating to obtain a fourth dispersion.
Have,
The content of the metal oxide particles in the mixed solution of the step B 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. Mass% or more and 98 mass% or less,
The step D of adding the hydrophobic solvent is a step d1 of adding the hydrophobic solvent at a rate at which the metal oxide particles do not aggregate after heating the first dispersion liquid, while heating the first dispersion liquid. , The step d2 of adding the hydrophobic solvent at a rate at which the metal oxide particles do not agglomerate, or after adding the hydrophobic solvent at a rate at which the metal oxide particles do not agglomerate, the first dispersion liquid is heated. Step d3.

The total content of the silane compound and the metal oxide particles can also be evaluated by the solid content.
Further, the total content of the silane compound and the metal oxide particles does not include alcohol generated by hydrolysis of the silane compound 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. Needless to say, the total content is a value including the content of the metal oxide particles attached to the silane compound.

Further, in the present embodiment, prior to each of the above steps, there may be a step A (hydrolysis step) in which the silane compound and water are mixed to obtain a hydrolyzed solution containing the hydrolyzed silane compound. good.
Hereinafter, each step will be described in detail.

(Step A (hydrolysis step))
In the hydrolysis step, the silane compound and water are mixed to obtain a hydrolyzed solution containing the hydrolyzed silane compound. By using the mixed solution in which at least a part of the silane compound is hydrolyzed in advance in this way, the silane compound easily adheres to the metal oxide particles in the dispersion step described later.

As the silane compound, one of the above-mentioned silane compounds can be used alone or in combination of two or more.
The content of the silane compound in the hydrolyzed solution is not particularly limited and can be the balance of other components in the hydrolyzed solution, but may be, for example, 60% by mass or more and 99% by mass or less. It is more preferably 70% by mass or more and 97% by mass or less, and further preferably 80% by mass or more and 95% by mass or less.

In the hydrolysis step, a surface modifying material other than the silane compound may be contained in the hydrolysis liquid.

Further, in the hydrolysis step, the hydrolyzed liquid contains water. Water serves as a substrate for the hydrolysis reaction of surface modifying materials such as silane compounds.
The content of water in the hydrolyzed solution is not particularly limited, and can be appropriately set according to, for example, the amount of the silane compound. For example, the amount of water added to the hydrolyzed 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, relative to 1 mol of the silane compound. It is more preferably 2 mol or less. Thereby, it is possible to more reliably prevent the agglutination of the metal oxide particles in the dispersion liquid produced by the excess amount of water while sufficiently proceeding the hydrolysis reaction of the silane compound.

Alternatively, the content of water in the hydrolyzed 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. It is more preferably less than or equal to%.

Further, a catalyst may be added to the hydrolyzed solution together with the 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 hydrolyzate. 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 particles, for example, a hydroxyl group or a silanol group. As a result, in the dispersion step (step C) described later, the silane compound including the silane compound easily adheres to the metal oxide particles, and the dispersion stability of the metal oxide particles is improved.

Here, the above-mentioned "acid" refers to an acid based on the definition of so-called Bronsted-Lowry, and refers to a substance that gives a proton in the hydrolysis reaction of a surface modifying material such as a silane compound. Further, the above-mentioned "base" refers to a base based on the definition of so-called Bronsted-Lowry, and here, refers to a substance that accepts protons in a hydrolysis reaction of a surface modifying material such as a silane compound and a subsequent condensation reaction. ..

The acid is not particularly limited as long as it can supply protons in the hydrolysis reaction of the silane compound, and is, for example, an inorganic acid such as hydrochloric acid, hydrobromic acid, hydroiodic acid, sulfuric acid, nitrate, boric acid, and phosphoric acid. And organic acids such as acetic acid, citric acid and formic acid. These organic 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 examples thereof include sodium hydroxide, potassium hydroxide, barium hydroxide, calcium hydroxide, ammonia, and amines. One of these bases may be used alone, or two or more of these bases may be used in combination.

Among the above, it is preferable to use an acid as the catalyst. As the acid, an inorganic acid is preferable, and hydrochloric acid is more preferable, from the viewpoint of acidity.

The content of the catalyst in the hydrolyzed solution is not particularly limited, but is preferably 10 ppm or more and 1000 ppm or less, more preferably 20 ppm or more and 800 ppm or less, and further preferably 30 ppm or more and 600 ppm or less. Thereby, the side reaction of the silane compound can be suppressed while sufficiently promoting the hydrolysis of the silane compound.

Further, the hydrolyzed solution may contain a hydrophilic solvent. The hydrophilic solvent promotes the mixing of water and the silane compound in the hydrolyzed solution, and further promotes the hydrolysis reaction of the silane compound.

Examples of such a hydrophilic solvent include various hydrophilic solvents that can be contained in the above-mentioned dispersion liquid.

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

The content of the hydrophilic solvent in the hydrolyzed solution is not particularly limited, but is preferably 60% by mass or less, more preferably 50% by mass or less, for example. As a result, the content of the silane compound and water in the hydrolyzed solution can be sufficiently increased. The content of the hydrophilic solvent in the hydrolyzed solution is, for example, preferably 10% by mass or more, and more preferably 15% by mass or more. As a result, the miscibility of the surface-modifying material and water can be further promoted, and as a result, the hydrolysis reaction of the surface-modifying material can be efficiently promoted. The hydrolysis solution may not contain a hydrophilic solvent other than the compound derived from the hydrolysis reaction.

In the present embodiment, when a silane compound having an alkoxy group is used as the silane compound, the alcohol compound derived from the alkoxy group is contained in the mixed solution in order to hydrolyze the silane compound. Since the hydrolysis reaction proceeds even with the adsorbed water of the metal oxide particles, it can occur in any of steps A to E. Therefore, unless there is a step of removing the alcohol compound, the obtained dispersion liquid contains the alcohol compound.

In the hydrolysis step, after preparing the hydrolyzed solution, it may be held at a constant temperature for a predetermined 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 appropriately changed depending on the type of the silane compound, but for example, it is preferably 5 ° C. or higher and 65 ° C. or lower, and 30 ° C. or higher and 60 ° C. or lower. More preferred.

The holding time is not particularly limited, but is preferably 10 minutes or more and 180 minutes or less, and more preferably 30 minutes or more and 120 minutes or less.
In holding the above-mentioned hydrolyzed solution, the hydrolyzed solution may be appropriately stirred.

(Step B (Mixing step))
In the mixing step, the silane compound and the metal oxide particles are mixed to obtain a mixed solution. In the mixing step, water or a catalyst may be mixed in addition to the silane compound and the metal oxide particles. When the hydrolyzed liquid is obtained by the above-mentioned hydrolysis step, the mixed liquid can be obtained by mixing the hydrolyzed liquid and the metal oxide particles.

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

As described above, in the present embodiment, the total content of the silane compound and the metal oxide particles in the mixed solution is very large. Then, the dispersion medium such as an organic solvent and water, which has been conventionally considered to be indispensable, is not contained in the mixed solution or is mixed only in a very small amount. Alternatively, it contains only a small amount of unavoidable alcohol compounds due to hydrolysis. Even in such a case, the metal oxide particles can be uniformly dispersed in the mixed solution by passing through the dispersion step, and the silane compound can be uniformly adhered to the metal oxide particles (surface modification). ) Is achieved.

More specifically, when metal oxide particles are surface-modified in a liquid phase with a surface-modifying material, not only the metal oxide particles and the surface-modifying material but also a dispersion medium are mixed to obtain a mixed solution, and the mixture is obtained. It is common to disperse the liquid using a disperser. Here, when such surface-modified metal oxide particles are mixed with the methyl-based silicone resin, they cannot be sufficiently dispersed in the methyl-based silicone resin and aggregate, resulting in the methyl-based silicone resin. There is a problem that turbidity such as white turbidity occurs. In such a case, the added metal oxide particles do not sufficiently exhibit the desired performance.

The dispersion medium is usually added for the purpose of lowering the viscosity of the mixture, uniformly dispersing the metal oxide particles, and uniformly modifying the surface of the metal oxide particles with the surface modifying material. Conventionally, it has been considered that when a dispersion medium is not used, the surface modifying material does not sufficiently adhere to the surface of the metal oxide particles as a result of the increase in the viscosity of the dispersion liquid. Surprisingly, the present inventors do not use or use only a small amount of such a dispersion medium which has been conventionally considered to be essential, and disperse the metal oxide particles directly in the high concentration silane compound. It has been found that uniform dispersion of the metal oxide particles is achieved in the obtained dispersion liquid, and uniform modification of the silane compound to the metal oxide particles is possible.

Silane compounds are small molecules and have a relatively low viscosity. Further, since it is hydrolyzed in the above-mentioned hydrolysis step, the adhesion to the metal oxide particles is good. Therefore, the silane compound is extremely suitable for dispersing metal oxide particles in a high-concentration surface-modifying material.

When the total content of the silane compound and the metal oxide particles is less than 65% by mass, the amount of components other than the above two components, for example, the dispersion medium becomes too large, and the silane compound is used in the dispersion step (step C) described later. It cannot be sufficiently adhered to the surface of the metal oxide particles. As a result, a large amount of hydroxyl groups remain on the surface of the metal oxide particles, and when the obtained dispersion is mixed with the hydrophobic material, the metal oxide particles agglomerate and the hydrophobic material becomes turbid. .. The total content of the silane compound and the metal oxide particles may be 65% by mass or more, preferably 70% by mass or more, and more preferably 75% by mass or more.

On the other hand, when the total content of the silane compound and the metal oxide particles exceeds 98% by mass, the viscosity of the mixed solution becomes too high, and the silane compound is sufficiently used in the dispersion step (step C) described later. Cannot adhere to the surface of metal oxide particles. The total content of the silane compound and the metal oxide particles may be 98% by mass or less, preferably 97% by mass or less, and more preferably 95% by mass or less.

Further, as described above, the content of the metal oxide particles in the mixed liquid is 10% by mass or more and 49% by mass or less. As a result, the amount of the silane compound with respect to the metal oxide particles can be kept within an appropriate range, the silane compound can be uniformly adhered to the surface of the metal oxide particles, and the increase in the viscosity of the mixed solution can be suppressed. can do.

On the other hand, when the content of the metal oxide particles in the mixed solution is less than 10% by mass, the amount of the silane compound is excessive with respect to the metal oxide particles, and the excess silane compound is contained in the obtained dispersion. Induces agglomeration of metal oxide particles. The content of the metal oxide particles in the mixed solution is preferably 20% by mass or more, and more preferably 30% by mass or more.

Further, when the content of the metal oxide particles exceeds 49% by mass, the amount of the silane compound is insufficient with respect to the metal oxide particles, and a sufficient amount of the silane compound does not adhere to the metal oxide particles. Further, as a result of the content of the metal oxide particles becoming too large, the viscosity of the mixed solution becomes too large, and the metal oxide particles cannot be sufficiently dispersed in the dispersion step (step C) described later. The content of the metal oxide particles in the mixed solution is preferably 45% by mass or less, and more preferably 40% by mass or less.

The content of the silane compound with respect to the content of the metal oxide particles in the mixed solution is not particularly limited, but is preferably 100% by mass or more and 800% by mass or less, and is 140% by mass or more and 600% by mass or less. More preferably, it is 180% by mass or more and 400% by mass or less. Thereby, the amount of the silane compound with respect to the metal oxide particles can be set within an appropriate range, and the silane compound can be uniformly adhered to the surface of the metal oxide particles.

Further, in the mixing step, an organic solvent may be further mixed with the mixed liquid. By mixing the organic solvent with the mixed solution, it is possible to control the reactivity of the surface-modifying material, and it is possible to control the degree of adhesion of the surface-modifying material to the surface of the metal oxide particles. Further, the organic solvent makes it possible to adjust the viscosity of the mixed solution.

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

The content of the organic solvent in the mixed solution is not particularly limited as long as it satisfies the contents of the metal oxide particles and the silane compound described above. Needless to say, the mixed solution does not have to contain an organic solvent.

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

The metal oxide particles can be dispersed by a known disperser. As the disperser, for example, a bead mill, a ball mill, a homogenizer, a disper, a stirrer and the like are preferably used.

Here, in the dispersion step, excessive energy is not applied but the minimum necessary energy is applied so that the particle size (dispersed particle size) of the metal oxide particles in the dispersion liquid becomes substantially uniform, and the mixture is mixed. It is preferable to disperse the metal oxide particles in the liquid.

(Step D (addition step (first addition step)))
In the addition step, a hydrophobic solvent is added to the above-mentioned first dispersion liquid to adjust the dispersion liquid to a desired solid content (concentration).
Since the first dispersion liquid obtained in the dispersion step has a high solid content (concentration), it has a high viscosity and poor handleability. However, when a hydrophobic solvent is added to the obtained first dispersion in order to reduce the solid content, the particles are aggregated due to the low hydrophobicity of the particle surface, and a uniform dispersion cannot be obtained. rice field.

Therefore, the present inventors have also found that the obtained dispersion liquid can be heated and gradually added with a hydrophobic solvent to prepare a dispersion liquid having a low solid content.

The mechanism is presumed as follows.
By heating the dispersion liquid, the polymerization of the silane compound adhering to the metal oxide particles proceeds, and the hydrophobicity of the particle surface is improved. Since the metal oxide particles aggregate even if the polymerization reaction proceeds too much, the surface is gradually surfaced while suppressing the excessive polymerization reaction by gradually adding a hydrophobic solvent to the dispersion liquid in which the polymerization reaction is in progress. Hydrophobicized and hydrophobic solvents can be mixed gradually.

That is, by adding an amount of the hydrophobic solvent that does not cause the metal oxide particles to agglomerate and proceeding the polymerization reaction of the silane compound to the extent that it can be compatible with the added amount of the hydrophobic solvent, the desired solid content is obtained. A conditioned dispersion can be obtained.

As described above, the hydrophobic solvent may be added gradually so that the metal oxide particles do not aggregate. Therefore, the hydrophobic solvent may be added after heating the first dispersion liquid, or the first dispersion liquid may be heated after adding the hydrophobic solvent, and the heating of the first dispersion liquid may be performed. The hydrophobic solvent may be added at the same time.
That is, the addition step may be the step d1 in which the above-mentioned hydrophobic solvent is added at a rate at which the above-mentioned metal oxide particles do not aggregate after the above-mentioned first dispersion liquid is heated, and the above-mentioned first dispersion. The step d2 may be performed in which the above-mentioned hydrophobic solvent is added at a rate at which the above-mentioned metal oxide particles do not agglomerate while heating the liquid, or the above-mentioned rate at which the above-mentioned hydrophobic solvent does not agglomerate. The step d3 may be a step of heating the above-mentioned first dispersion liquid after the addition in the above step d3.

The rate at which the metal oxide particles do not aggregate is not particularly limited. For example, the hydrophobic solvent may be continuously added at a rate such that the solid content is lowered in the range of 3% by mass or more and 20% by mass or less in 1 hour. The amount of the hydrophobic solvent added may be appropriately adjusted so that the amount of the hydrophobic solvent added is increased when the heating temperature is high and the amount of the hydrophobic solvent is decreased when the heating temperature is low.

For example, the hydrophobic solvent may be added stepwise every 30 minutes, 1 hour, or 2 hours so that the solid content is low in the range of 3% by mass or more and 20% by mass or less. When the heating temperature is high, the amount of the hydrophobic solvent added at one time is large, and when the heating temperature is low, the amount of the hydrophobic solvent added at one time is small. Should be adjusted as appropriate.

The heating temperature is not particularly limited as long as it is the 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. When the heating temperature is 35 ° C. or higher, the polymerization reaction of the silane compound can proceed. On the other hand, when the heating temperature is 80 ° C. or lower, aggregation of metal oxide particles due to a rapid reaction of the silane compound can be suppressed.

The heating time may be appropriately carried out until the adjustment of the solid content is completed, and is preferably 4 hours or more and 12 hours or less, for example. When the heating time is 4 hours or more, the polymerization reaction of the silane compound proceeds, and it becomes possible to mix with the hydrophobic solvent. On the other hand, when the heating time is 12 hours or less, it is possible to suppress the aggregation of the metal oxide particles due to the excessive progress of the polymerization reaction of the silane compound.

The hydrophobic solvent is not particularly limited as long as it is compatible with the material to be mixed with the dispersion liquid of the present 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. Of these, aromatics, especially aromatic hydrocarbons, are preferred. Aromatic compounds have excellent compatibility with methyl silicone resins, and contribute to improving the viscosity characteristics of the resulting composition and improving the quality (transparency, shape, etc.) of the sealing member to be formed.

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

Among these, toluene, o-xylene, and m-xylene are examples of aromatic hydrocarbons from the viewpoint of the stability of the dispersion and the ease of handling in removing the dispersion medium during the production of the composition described later. , P-Xylene and at least one selected from the group consisting of benzene are particularly preferably used.

The content of the hydrophobic solvent contained in the final dispersion may be appropriately adjusted so as to have a desired solid content. 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.
The first addition step gives a second dispersion adjusted to the desired solid content. By using the second dispersion liquid, the handleability of the dispersion liquid in the following steps is improved.

(Step G (removal step))
In the present embodiment, a step G for removing alcohol generated by hydrolysis may be provided between the step D and the step E.
It is presumed that the production efficiency of the process described below is improved by providing the removal process.
The method of removing is not particularly limited, but for example, an evaporator can be used.
The removal step may be carried out until the alcohol is completely removed, or about 5% by mass may remain.

(Step E (second addition step))
Next, the metal oxide particles are treated with a silicone compound to obtain a third dispersion. As described above, in the dispersion step, the silane compound adheres relatively uniformly 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 held at a constant temperature for a predetermined time. Thereby, the adhesion of the silicone compound to the metal oxide particles can be further promoted.

Examples of the silicone compound include the above-mentioned silicone compounds. 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, it can be mixed with the second dispersion so as to be 100% by mass or more and 300% by mass or less. As a result, a sufficient amount of the silicone compound can be adhered to the surface of the metal oxide particles, the dispersion stability of the metal oxide particles can be improved, and the dispersibility in the methyl silicone resin can be improved. can. Further, the amount of the liberated silicone compound can be reduced, and the unintentional aggregation of the 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 appropriately changed depending on the type of the silicone compound. For example, it is preferably 40 ° C. or higher and 130 ° C. or lower, and 50 ° C. or higher and 120 ° C. or lower. More preferred.

The holding time is not particularly limited, but is preferably 1 hour or more and 24 hours or less, and more preferably 2 hours or more and 20 hours or less.
In the above-mentioned holding, the second dispersion liquid may be appropriately stirred.

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

(Step F (replacement step))
In the replacement step, alcohol is added to the third dispersion and heated to hydrolyze the alkoxy group of the silane compound to form an OH group, which is not bonded to the surface of the metal oxide particles. Substitutes the OH group of the above with an alkoxy group.
When an alcohol having a larger number of carbon atoms than the alkoxy group of the silane compound is used, the unhydrolyzed unreacted alkoxy group is replaced with the alkoxy group having a larger number of carbon atoms in the silane compound alkoxy group. By substituting the unreacted alkoxy group with an alkoxy group having a larger number of carbon atoms, it is possible to prevent the unreacted alkoxy group from being hydrolyzed to an OH group due to moisture in the atmosphere or the like.
If an OH group is present on the surface of the metal oxide particles, it is presumed that the dehydration condensation reaction between the silane compounds and the silane compound and the silicone compound proceeds. As a result, such a mixture of the surface-modified metal oxide particles and the resin tends to increase in viscosity and has poor stability over time.
In step F, the OH group is replaced with an alkoxy group, and the alkoxy group having a small number of carbon atoms is replaced with an alkoxy group having a large number of carbon atoms, thereby suppressing the dehydration condensation reaction between the silane compounds and stabilizing over time. Has a role to improve.

Alcohol may be added and heated at the same time. Further, in order to increase the efficiency of the substitution reaction, it is preferable to heat the dispersion while stirring.

The carbon number of the alcohol to be added is preferably 1 or more and 6 or less, preferably 1 or more and 5 or less, and more preferably 2 or more and 4 or less. When the carbon number of the alcohol is in the above range, the OH group is easily replaced with the alkoxy group, and the stability over time after the replacement step can be improved.

The heating temperature is not particularly limited as long as the substitution reaction proceeds, and may be set to a temperature of about the boiling point of the alcohol used. For example, it is preferably 60 ° C. or higher and 160 ° C. or lower.
The heating time may be a time sufficient to complete the substitution reaction, for example, 0.5 hours or more and 72 hours or less.

In the replacement step, if the alcohol remains excessively after the heating is completed, a step of removing the alcohol may be provided.
The method of removing is not particularly limited, but for example, an evaporator can be used.
The removal step may be carried out until the alcohol is completely removed, or about 5% by mass may remain.

Further, in the replacement step, the solid content may be measured after heating, and a hydrophobic solvent may be added so as to obtain a desired solid content. By reducing the solid content, mixing with a methyl silicone resin described later becomes easy.

In the dispersion liquid produced by the method for producing the dispersion liquid according to the present embodiment, the metal oxide particles are uniformly dispersed, and the surface of the metal oxide particles is uniformly and sufficiently modified by the silane compound and the silicone compound. ing. The metal oxide particles modified in this way have excellent affinity with the methyl silicone resin and can be dispersed relatively uniformly in the methyl silicone resin. Therefore, even when the metal oxide particles are dispersed in the methyl silicone resin, the generation of turbidity such as white turbidity is suppressed. Furthermore, the change in viscosity of the methyl silicone resin containing the metal oxide particles is also suppressed.

If necessary, the dispersion liquid according to the present embodiment includes components other than those described above, such as a dispersant, a dispersion aid, an antioxidant, a flow regulator, a thickener, a pH regulator, and a preservative. General additives and the like may be mixed. These are added in any step as needed.

As described above, in the dispersion liquid of the present embodiment, the metal oxide particles can be mixed with the hydrophobic material by directly dispersing the metal oxide particles in the silane compound. It is presumed that more silane compounds are attached to the metal oxide particles and more densely coated than the conventional dispersion liquid. However, it is unclear what the surface of the metal oxide particles is so that the dispersion can be mixed with the hydrophobic material. Therefore, it is impossible to directly identify the characteristics of the dispersion liquid of the present embodiment by the state of the surface of the metal oxide particles modified with the silane compound and the silicone compound. Considering that the dispersion contains metal oxide particles, one or more silane compounds and one or more silicone compounds having at least a part adhered to the metal oxide particles, and a hydrophobic solvent, the metal oxide. The general specification of the surface condition for allowing the particles to be mixed with the hydrophobic material is that the metal oxide particles can be mixed with the hydrophobic material, and the structure of the silane compound and the silicone compound. It is almost impossible in light of the fact that it is presumed to be expressed by the complex entanglement of many factors such as the degree of polymerization in the dispersion, the shape, particle size, particle size distribution, and specific surface area of the metal oxide particles. ..

<4. Composition>
Next, the composition according to this embodiment will be described.
The composition according to this embodiment is a mixture of the above-mentioned dispersion liquid and a resin component. Therefore, the composition according to the present embodiment contains at least one of a resin component, that is, a resin and a precursor thereof, in addition to the metal oxide particles surface-modified with the above-mentioned silane compound and silicone compound.

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

Furthermore, since the composition according to the present embodiment contains metal oxide particles surface-modified with the above-mentioned silane compound and silicone compound, even when a methyl-based silicone resin is contained as a resin component, the metal is used. Aggregation of oxide particles is suppressed, and deterioration of transparency is suppressed. Therefore, when the composition according to the present embodiment is used for the sealing member, the brightness of the light of the light emitting device can be improved.

The content of the metal oxide particles in the composition of the present embodiment is preferably 5% by mass or more and 50% by mass or less, and 5% by mass or more and 40% by mass or less, from the viewpoint of obtaining a highly transparent composition. It is more preferably 10% by mass or more and 35% by mass or less.

Further, the content of the surface modifying material such as the silane compound and the silicone compound can correspond to the content in the dispersion liquid according to the present embodiment.

The resin component is the main component in the composition according to the present embodiment. When the composition according to the present embodiment is used as a sealing material, the resin component is cured to seal the light emitting element, so that deterioration factors from the external environment such as moisture and oxygen reach the light emitting element. To prevent. Further, in the present embodiment, the cured product obtained from the resin component is basically transparent and can transmit the 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, a resin such as a silicone resin or an epoxy resin may be used alone or in combination of two or more. You may. In particular, from the viewpoint of durability, a silicone resin, particularly a methyl silicone resin, is preferable.

As the methyl silicone resin, for example, a dimethyl silicone resin, a methyl phenyl silicone resin, or the like can be used.

The content of the methyl silicone resin in the resin component may be adjusted according to desired characteristics, and is not particularly limited. For example, it may be 100% by mass or 20% by mass or more and 80% by mass or less. It may be 30% by mass or more and 70% by mass or less, and may be 40% by mass or more and 60% by mass or less. Conventionally, when metal oxide particles are contained in a methyl silicone resin, the metal oxide particles are aggregated, the transparency is lowered, and the refractive index is not sufficiently improved. On the other hand, since the composition according to the present embodiment contains metal oxide particles surface-modified with the above-mentioned silane compound and silicone compound, when a large amount of methyl silicone resin is contained as a resin component in this way. Even so, the aggregation of the metal oxide particles is suppressed, and the decrease in transparency is suppressed. On the other hand, since it is possible to use a methyl silicone resin, the durability of the sealing member formed by 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-type structure.
The resin component may be in the form of a polymer that has been cured when used as a sealing member, and may be in a state before curing, that is, a precursor in the composition. Therefore, the resin component present in the composition may be a monomer, an oligomer, or a polymer.

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

The content of the resin component in the composition according to the present embodiment can be the balance of other components, but is preferably 10% by mass or more and 70% by mass or less, for example.
The mass ratio of the resin component to the surface-modified metal oxide particles in the composition according to the present embodiment is the resin component: surface-modified metal oxide particles, and is in the range of 50:50 to 90:10. It is preferably in the range of 60:40 to 80:20, and more preferably in the range of 60:40 to 80:20.

The composition according to the present embodiment may contain a dispersion medium derived from the dispersion liquid according to the present embodiment, or may be removed. That is, the dispersion medium derived from the dispersion liquid may be completely removed, or about 1% by mass or more and 10% by mass or less may remain in the composition, or about 2% by mass or more and 5% by mass or less may remain. May be good.

In addition, the composition according to the present embodiment may contain phosphor particles as long as the object of the present invention is not impaired. The phosphor particles absorb the light of a specific wavelength emitted from the light emitting element and emit the light of a predetermined wavelength. That is, the phosphor particles can convert the wavelength of light and adjust the color tone.

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

In addition, the composition of the present embodiment contains commonly used additives such as preservatives, polymerization initiators, polymerization inhibitors, curing catalysts, photodiffusing agents, etc., as long as the object of the present invention is not impaired. It may have been done. As the light diffusing agent, it is preferable to use silica particles having an average particle size of 1 μm to 30 μm.

The composition according to the present embodiment can be produced by mixing the dispersion liquid according to the present embodiment and the resin component. Further, after mixing, the dispersion medium contained in the dispersion liquid may be removed by an evaporator or the like, if necessary.

Since the composition according to the present embodiment contains metal oxide particles surface-modified with the above-mentioned silane compound and silicone compound, the metal oxide particles are contained even when a methyl silicone resin is contained as a resin component. Aggregation is suppressed and the decrease in transparency is suppressed. Therefore, the composition according to the present embodiment can be used to form a sealing member that improves the brightness of the light of the light emitting device.

<5. Sealing member>
The sealing member according to this embodiment is a cured product of the composition according to this embodiment. The sealing member according to the present embodiment is usually used as a sealing member or a part thereof arranged on the light emitting element.
The thickness and shape of the sealing member according to the present embodiment can be appropriately adjusted according to desired applications and characteristics, and are not particularly limited.

The sealing member according to the present embodiment can be produced by curing the composition according to the present embodiment as described above. The curing method of the composition can be selected according to the characteristics of the resin component in the composition according to the present embodiment, and examples thereof include thermosetting and electron beam curing. More specifically, the sealing member of the present embodiment can be obtained by curing the resin component in the composition of the present embodiment by an addition reaction or a polymerization reaction.

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

The average dispersed particle diameter of the metal oxide particles in the sealing member is an average particle diameter (median diameter) based on the number distribution, which is measured by transmission electron microscope observation (TEM) of the sealing member. The average dispersed particle size of the metal oxide particles in the sealing member according to the present embodiment is a value measured and calculated based on the dispersed particle size of the metal oxide particles in the sealing member. The average dispersed particle size is measured and calculated based on the diameter of the dispersed metal oxide particles regardless of whether the metal oxide particles are dispersed in the primary particles or the secondary particles. .. Further, in the present embodiment, the average particle size of the metal oxide particles in the sealing member may be measured as the average particle size of the metal oxide particles to which the surface modifying material described later is attached. Since metal oxide particles to which the surface modifying material is attached and metal oxide particles to which the surface modifying material is not attached may be present in the sealing member, the metal oxide particles in the sealing member are usually present. The average particle size is measured as a value in these mixed states.

Since the sealing member according to the present embodiment is a cured product of the composition according to the present embodiment, it is excellent in refractive index and transparency. Therefore, according to the present embodiment, it is possible to obtain a sealing member having excellent extraction efficiency that improves the brightness of the light of the light emitting device.

<6. Light emitting device>
Next, the light emitting device according to the present embodiment will be described. The light emitting device according to the present embodiment includes the above-mentioned sealing member and a light emitting element sealed in the sealing member.

Examples of the light emitting element include a light emitting diode (LED) and an organic light emitting diode (OLED). In particular, the sealing member according to this embodiment is suitable for sealing a light emitting diode.

Hereinafter, the light emitting device according to the present embodiment will be described with reference to an example in which the light emitting element is a light emitting diode on the chip, that is, an LED chip, and the light emitting device is an LED package.
1 to 4 are schematic views (cross-sectional views) showing an example of a light emitting device according to an embodiment of the present invention, respectively.
The size of each member in the drawing is emphasized as appropriate for ease of explanation, and does not indicate the actual size or the ratio between the members. In the present specification and the drawings, components having substantially the same functional configuration are designated by the same reference numerals, so that duplicate description will be omitted.

The light emitting device (LED package) 1A shown in FIG. 1 covers a substrate 2 having a recess 21, a light emitting element (LED chip) 3 arranged on the bottom surface of the recess 21 of the substrate 2, and a light emitting element 3 in the recess 21. It is provided with a sealing member 4A for sealing as described above.
The sealing member 4A is composed of the sealing member according to the present embodiment described above. Therefore, the metal oxide particles derived from the composition according to 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. Further, the phosphor particles 5 are dispersed in the sealing member 4A. The phosphor particles 5 convert at least a part of the wavelengths 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 sealing members according to the present embodiment. In the first layer 41B, the phosphor particles 5 are dispersed. On the other hand, the second layer 43B does not contain the phosphor particles 5. The light emitting device 1B emits light because the metal oxide particles derived from the composition according to the present embodiment described above are dispersed in the first layer 41B and the second layer 43B constituting the sealing member 4B. Brightness is improving.

The light emitting device 1C shown in FIG. 3 is also different 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 according to the present embodiment, but the above-mentioned sealing member of a resin containing no metal oxide particles, and is composed of a resin or the like that can be used for the sealing member. .. Further, in the first layer 41C, the phosphor particles 5 are dispersed. On the other hand, the second layer 43C is a sealing member according to the present embodiment. In the light emitting device 1C, the metal oxide particles derived from the composition according to 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. ing.

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

The light emitting device according to the present embodiment is not limited to the illustrated embodiment. For example, the light emitting device according to the present embodiment does not have to contain phosphor particles in the sealing member. Further, the sealing member according to the present embodiment can exist at an arbitrary position in the sealing member.

As described above, in the light emitting device according to the present embodiment, since the light emitting element is sealed by the sealing member of the present embodiment, the brightness of light is improved.

Further, in the light emitting device according to the present embodiment, the light emitting element is sealed by the composition according to the present embodiment as described above. Therefore, in one aspect, the present invention also relates to a method for manufacturing a light emitting device having a step of sealing a light emitting element using the composition according to the present embodiment. On the same aspect, the production method may include a step of mixing the dispersion liquid and the resin component according to the present embodiment to obtain the composition.

The light emitting element can be sealed by, for example, applying the composition according to the present embodiment onto the light emitting element with a dispenser or the like, and then curing the composition.

<7. Lighting equipment, display device>
The light emitting device according to the present embodiment as described above can be used for, for example, a lighting fixture and a display device. Therefore, in one aspect, the present invention relates to a luminaire or display device including a light emitting device according to the present embodiment.
Examples of the lighting equipment include general lighting devices such as indoor lights and outdoor lights, and lighting of switch portions of electronic devices such as mobile phones and OA devices.
Since the lighting fixture according to the present embodiment includes the light emitting device according to the present embodiment, the luminous flux emitted is larger than that in the conventional case even if the same light emitting element is used, and the surrounding environment can be made brighter. can.

Examples of the display device include a mobile phone, a personal digital assistant, an electronic dictionary, a digital camera, a computer, a television, and peripheral devices thereof.
Since the display device according to the present embodiment includes the light emitting device according to the present embodiment, the luminous flux emitted is larger than that in the conventional case even if the same light emitting element is used, for example, a clearer and brighter display. It can be performed.

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

[Example 1]
(1. Preparation of dispersion liquid)
(I) Hydrolysis step Methyltrimethoxysilane (product name: KBM-13, manufactured by Shinetsu Kogyo Kagaku Co., Ltd.) 90.78 parts by mass, 9.21 parts by mass of water, and 0.01 parts by mass of hydrochloric acid (1N). It was added and mixed to obtain a hydrolyzed solution. Next, this hydrolyzed solution was stirred at 60 ° C. for 30 minutes to hydrolyze methyltrimethoxysilane to obtain a hydrolyzed solution.

_{(Ii) Mixing Step 30 parts by mass of zirconium oxide (ZrO 2} ) particles (manufactured by Sumitomo Osaka Cement Co., Ltd.) having an average primary particle diameter of 12 nm and 70 parts by mass of the above hydrolyzed solution were mixed to obtain a mixed solution. The content of zirconium oxide particles in the mixed solution was 30% by mass, the content of methyltrimethoxysilane was 63.5% by mass, and the total content of zirconium oxide particles and methyltrimethoxysilane was 93.5% by mass. rice field.

(Iii) Dispersion Step This mixed solution was dispersed in a bead mill for 6 hours, and then the beads were removed to obtain a first dispersion.
As a result of measuring the solid content (1 hour at 100 ° C.) of the first dispersion liquid, it was 70% by mass.

(Iv) First Addition Step The obtained dispersion was heated at 60 ° C. for 2 hours. Next, toluene was added to the dispersion so that the solid content 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 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 was 20% by mass, and the mixture was heated at 60 ° C. for 1 hour to obtain a second dispersion.

(Iv) Second Addition Step 88.1 parts by mass of the second dispersion liquid whose solid content was adjusted to 20% by mass with toluene and a methoxy group-containing phenyl silicone resin (trade name: KR217, manufactured by Shin-Etsu Chemical Co., Ltd.). After mixing with 11.9 parts by mass to obtain a treatment liquid, this treatment liquid was heated at 110 ° C. for 1 hour to obtain a dispersion liquid (third dispersion liquid).

(V) Substitution Step Ethanol was added to the third dispersion liquid, and the mixture was heated and stirred at 80 ° C. to obtain the dispersion liquid (fourth dispersion liquid) according to Example 1.

(2. Evaluation of dispersion liquid)
(I) Particle size distribution A part of the obtained dispersion liquid according to Example 1 was sampled, and D10, D50, and D90 of zirconium oxide particles in the dispersion liquid whose solid content was adjusted to 5% by mass with toluene were distributed in particle size distribution. The measurement was performed using a meter (model number: SZ-100SP, manufactured by HORIBA). As a result, D10 was 101 nm, D50 was 119 nm, and D90 was 141 nm. Since the particles contained in the dispersion are basically only zirconium oxide particles to which a surface modifying material (methyltrimethoxysilane, methoxy group-containing phenylsilicone resin) is attached, the measured D10, D50, and D90 are It was considered to be D10, D50 and D90 of the zirconium oxide particles.

(Ii) FT-IR analysis 10 g of the dispersion liquid according to Example 1 in which the solid content was adjusted to 30% by mass with toluene was used in a vacuum dryer (manufactured by EYELA Tokyo Rikaki Co., Ltd., device name: VACUUM OVEN VOS-201SD). , 100 ° C., 20 hPa and dried for 2 hours. Next, using the obtained metal oxide particles of 0.01 g to 0.05 g, a Fourier transform infrared spectrophotometer (model number: FT / IR-670 Plus, manufactured by JASCO Corporation) was used to measure 800 cm ^-1 or more. The transmission spectrum in the wave number range of 3800 cm ^{-1 or less was measured.} The maximum value of the spectrum in the measurement range 100, the minimum value by normalizing the value of the spectrum as a 0, to determine the values of the 3500 cm ^-1 and ^{(IA) 1100cm -1 (IB)} . As a result, the IA was 47.1, the IB was 25.7, and the IA / IB was 1.8. The results are shown in Table 1.

(3. Preparation of composition)
5.0 g of the dispersion liquid according to Example 1 in which the solid content was adjusted to 30% by mass with toluene was mixed with 3.5 g of methylphenyl silicone (trade name: KER-2500-B, manufactured by Shin-Etsu Chemical Co., Ltd.). That is, the total mass of the zirconia and the surface modifying material and the methylphenyl silicone were mixed so as to have a mass ratio of 30:70.
Then, toluene was removed from this mixed solution by an evaporator to obtain the composition according to Example 1.
As a result of visually observing the appearance of the obtained composition according to Example 1, it was transparent. As a result, it was confirmed that the zirconium oxide particles were relatively uniformly dispersed in the composition with suppressed aggregation.

(Evaluation of composition stability)
The viscosity of the composition of Example 1 was measured using a rheometer (trade name: Leostress RS-6000, manufactured by HAAKE) under the conditions of 25 ° C. and a breaking speed of 1 (1 / s).
As a result, the viscosity was 6.3 Pa · s.
This composition was stored at room temperature (25 ° C.), and the viscosity after 1 month was measured. As a result, the viscosity of the composition was 32.6 Pa · s, which was a level sufficiently tolerable for practical use, although the viscosity was increased. From this, it was confirmed that the zirconium oxide particles were stably dispersed in the composition for a long period of time.

(4. Manufacturing of LED package and evaluation of brightness)
14 parts by mass of methylphenyl silicone resin (trade name: KER-2500-A / B, manufactured by Shin-Etsu Chemical Co., Ltd.) was added to 1 part by mass of the composition of Example 1, and surface-modified zirconium oxide particles were added to the composition. The mixture was adjusted to 2% by mass and mixed. A composition obtained by mixing 0.38 parts by mass of phosphor particles (yttrium aluminum garnet: YAG) with 1 part by mass of this composition (total amount of surface-modified zirconium oxide particles and resin: phosphor particles = 100: 38). , The LED lead frame was filled with a thickness of 300 μm. Then, it was kept at room temperature for 3 hours. The composition was then slowly heat-cured to form a sealing member to produce a white LED package.

The brightness of the obtained white LED package was measured 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.). As a result, the brightness of this white LED package was 74.4 lm.

[Example 2]
In Example 2 in the same manner as in Example 1 except that zirconium oxide particles having an average primary particle size of 90 nm (manufactured by Sumitomo Osaka Cement Co., Ltd.) were used instead of the zirconium oxide particles having an average primary particle size of 12 nm. Such a dispersion liquid (third dispersion liquid) was obtained. The content of zirconium oxide particles in the mixed solution obtained in the mixing step was 30% by mass, the content of methyltrimethoxysilane was 63.5% by mass, and the total content of zirconium oxide particles and methyltrimethoxysilane was 93. It was 5.5% by mass.
As a result of measuring the solid content (1 hour at 100 ° C.) of the first dispersion liquid, it was 70% by mass.

As a result of evaluating the particle size distribution of the zirconium oxide particles in the dispersion liquid according to Example 2 with a dispersion liquid in which the solid content was adjusted to 5% by mass with toluene in the same manner as in Example 1, D10 was 116 nm, D50 was 150 nm, and D90. Was 296 nm.
Further, as a result of performing FT-IR analysis on the dispersion liquid according to Example 2 in the same manner as in Example 1, IA was 45.3, IB was 24.9, and IA / IB was 1.8. ..

The composition according to Example 2 was obtained by mixing the dispersion liquid according to Example 2 in which the solid content was adjusted to 30% by mass with toluene with methylphenyl silicone in the same manner as in Example 1 and removing toluene. rice field. As a result of visually observing the appearance of the obtained composition, it was a transparent composition.

As a result of measuring the viscosity of the composition in the same manner as in Example 1, the viscosity immediately after production was 5.3 Pa · s.
This composition was stored at room temperature (25 ° C.), and the viscosity after 1 month was measured. As a result, the viscosity of the composition was 31.8 Pa · s, which was a level sufficiently tolerable for practical use, although the viscosity was increased.

A white LED package was produced in the same manner as in Example 1 except that the composition according to Example 2 was used instead of the composition according to Example 1. As a result, the brightness of this white LED package was 74.1 lm.

[Comparative Example 1]
Exactly the same as in Example 1 except that 20 parts by mass of the hydrolyzed liquid and 50 parts by mass of isopropyl alcohol (IPA) were used instead of mixing 70 parts by mass of the hydrolyzed liquid in the mixing step. , The mixing step and the dispersion step were carried out to obtain a dispersion liquid (first dispersion liquid).
As a result of measuring the solid content of the dispersion liquid (1 hour at 100 ° C.), it was 38% by mass.

(Iv) First Addition Step Toluene was added to the obtained dispersion liquid (first dispersion liquid) so that the solid content was 20% by mass, and the mixture was heated at 60 ° C. for 2 hours. Then, the same amount of toluene as the volatilized amount was added to the dispersion, and the mixture was heated at 60 ° C. for 2 hours. Then, the same amount of toluene as the volatilized amount was added to the dispersion liquid, and the mixture was heated at 60 ° C. for 1 hour. Next, the same amount of toluene as the volatilized amount was added to the dispersion liquid, and the dispersion liquid was heated at 60 ° C. for 1 hour to promote surface modification, and the dispersion liquid in which isopropyl alcohol was replaced with toluene (second dispersion liquid). Got

(V) Second Addition Step 88.1 parts by mass of the second dispersion liquid having a solid content adjusted to 20% by mass, and a methoxy group-containing phenylsilicone resin (trade name: KR217, manufactured by Shin-Etsu Chemical Co., Ltd.) 11. 9 parts by mass and 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 (third dispersion liquid) according to Comparative Example 1.

As a result of evaluating the particle size distribution of the zirconium oxide particles in the dispersion liquid according to Comparative Example 1 with a dispersion liquid in which the solid content was adjusted to 5% by mass with toluene in the same manner as in Example 1, D10 was 91 nm, D50 was 112 nm, and D90. Was 136 nm.
Further, as a result of performing FT-IR analysis on the dispersion liquid according to Comparative Example 1 in which the solid content was adjusted to 30% by mass with toluene in the same manner as in Example 1, the IA was 42.1 and the IB was 10.0. , IA / IB was 4.2.

The dispersion liquid according to Comparative Example 1 in which the solid content was adjusted to 30% by mass with toluene was mixed with methylphenyl silicone in the same manner as in Example 1 and toluene was removed to obtain a composition according to Comparative Example 1. .. As a result, the composition according to Comparative Example 1 became cloudy, and it was not possible to obtain a composition capable of sealing the LED.

[Comparative Example 2]
The third dispersion obtained in the production process of Example 1 was used as the dispersion according to Comparative Example 2. That is, in Example 1, the dispersion liquid having no replacement step was used as the dispersion liquid according to Comparative Example 2.

As a result of evaluating the particle size distribution of the zirconium oxide particles in the dispersion liquid according to Comparative Example 2 with a dispersion liquid in which the solid content was adjusted to 5% by mass with toluene in the same manner as in Example 1, D10 was 104 nm, D50 was 122 nm, and D90. Was 143 nm.
Further, as a result of performing FT-IR analysis on the dispersion liquid according to Comparative Example 2 in the same manner as in Example 1, IA was 50.3, IB was 25.5, and IA / IB was 2.0. ..

The dispersion according to Comparative Example 2 in which the solid content was adjusted to 30% by mass with toluene was mixed with methylphenyl silicone in the same manner as in Example 1 to remove toluene to obtain a composition according to Comparative Example 2. rice field. As a result of visually observing the appearance of the obtained composition, it was a transparent composition.

As a result of measuring the viscosity of the composition in the same manner as in Example 1, the viscosity immediately after production was 6.5 Pa · s.
This composition was stored at room temperature (25 ° C.), and the viscosity after 1 month was measured. As a result, the viscosity of the composition was 85.4 Pa · s, which was a level that could withstand practical use, although the viscosity was increased.

A white LED package was produced in the same manner as in Example 1 except that the composition according to Comparative Example 2 was used instead of the composition according to Example 1. As a result, the brightness of this white LED package was 74.2 lm.

Table 1 summarizes the evaluation of the dispersion liquid production conditions, the dispersion liquid, and the composition in Example 1, Example 2, Comparative Example 1, and Comparative Example 2 as described above.

[Reference example]
A white LED package containing no surface-modified zirconium oxide particles was prepared, and the brightness was measured. That is, in the production of the LED package of Example 1, instead of setting the total amount of surface-modified zirconium oxide particles and resin: phosphor particles = 100: 38, the total amount of resin: phosphor particles = 100: 38 was set. A white LED package of a reference example was produced in the same manner as in Example 1 except for the above.
As a result of measuring the obtained white package in the same manner as in Example 1, the brightness of this white LED package was 72.5 lm.

As described above, in Examples 1 and 2 in which the zirconium oxide particles were dispersed in the high-concentration silane compound, the zirconium oxide particles were suitably dispersed even when the methylphenyl silicone and the dispersion liquid were mixed. No turbidity or excessive increase in viscosity was observed. It was also confirmed that the brightness of the white LED package can be improved.
On the other hand, in Comparative Example 1, when the methylphenyl silicone and the dispersion liquid were mixed, the obtained composition gelled and was unsuitable as a composition for sealing the light emitting device.
Further, by comparing Example 1 and Comparative Example 2, it was confirmed that an increase in the viscosity of the composition over time can be suppressed depending on the presence or absence of the replacement step.

Although the preferred embodiments of the present invention have been described in detail with reference to the accompanying drawings, the present invention is not limited to such examples. It is clear that a person having ordinary knowledge in the field of technology to which the present invention belongs can come up with various modifications or modifications within the scope of the technical ideas described in the claims. , These are also naturally understood to belong to the technical scope of the present invention.

1A, 1B, 1C, 1D light emitting device 2 substrate 21 recess 3 light emitting element 4A, 4B, 4C, 4D sealing member 41B, 41C, 41D first layer 43B, 43C, 43D second layer 45D third layer 5 Fluorescent particles

Claims (7)

A dispersion liquid containing metal oxide particles surface-modified with a surface-modifying material and a hydrophobic solvent.
The surface modification material contains a silane compound and a silicone compound, and contains
For the metal oxide particles obtained by drying the dispersion liquid by vacuum drying, ^{a transmission spectrum in a wave number range of 800 cm -1} or more and 3800 cm ^-1 or less is measured by a Fourier transform infrared spectrophotometer, and the transmission spectrum is measured in the range. When the spectrum values are standardized so that the maximum value of the spectrum is 100 and the minimum value is 0, the following equation (1):
IA / IB ≤ 3.5 (1)
(Wherein "IA", the spectral value at 3500 cm ^-1, "IB" respectively show the spectral values in the 1100 cm ^-1.)
Satisfy the dispersion. A composition which is a mixture of the dispersion liquid and the resin component according to claim 1. A sealing member which is a cured product of the composition according to claim 2. A light emitting device including 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 including the light emitting device according to claim 4. Step B of mixing the silane compound and the metal oxide particles to obtain a mixed solution,
Step C of dispersing the metal oxide particles in the mixed solution to obtain a first dispersion in which the metal oxide particles are dispersed.
Step D to obtain a second dispersion by adding a hydrophobic solvent to the first dispersion,
Step E of adding a silicone compound to the second dispersion to obtain a third dispersion,
In step F, in which alcohol is added to the third dispersion liquid and heated to obtain a fourth dispersion liquid,
Have,
The content of the metal oxide particles in the mixed solution of the step B 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. Mass% or more and 98 mass% or less,
The step D of adding the hydrophobic solvent is a step d1 of adding the hydrophobic solvent at a rate at which the metal oxide particles do not aggregate after heating the first dispersion liquid, while heating the first dispersion liquid. , The step d2 of adding the hydrophobic solvent at a rate at which the metal oxide particles do not agglomerate, or after adding the hydrophobic solvent at a rate at which the metal oxide particles do not agglomerate, the first dispersion liquid is heated. The method for producing a dispersion liquid, which is step d3.

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