JP7363634B2 - Dispersion liquid, composition, sealing member, light emitting device, lighting equipment, display device, and method for producing dispersion liquid - Google Patents

Description

The present invention relates to a dispersion 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 device, a display device, and a method for producing the dispersion.

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

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

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

International Publication No. 2016/142992

By the way, the present inventors have found that by incorporating metal oxide particles with a high refractive index into the sealing material, not only the light scattering properties of the resulting sealing member can be improved, but also the refractive index of the sealing member can be improved. We found that it is possible to When the refractive index of the sealing member improves, the efficiency of extracting light from the sealed light emitting element generally improves. When metal oxide particles are included in the sealing material for such purposes, it is advantageous to have a larger content of metal oxide particles from the viewpoint of improving the refractive index.

On the other hand, in recent years, in order to extend the lifespan of LEDs, there has been an increasing demand for methyl silicone resins with high heat resistance as sealing resins used as sealing materials. Methyl silicone resins have a higher content of methyl groups and a higher degree of hydrophobicity than phenyl silicone resins that have been commonly used in the past. Therefore, as in the invention described in Patent Document 1, even if metal oxide particles have a hydrophobic surface, when mixed with methyl silicone resin, the metal oxide particles aggregate with each other and become transparent. There was a problem that it was not possible to obtain a suitable composition. Such problems become more noticeable as the content of metal oxide particles in the sealing material increases.

The present invention was made to solve the above problems, and includes a dispersion liquid containing metal oxide particles and in which agglomeration of the metal oxide particles is suppressed when 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 fixture and a display device including the light emitting device, and a method for producing a dispersion are provided. The purpose is to

In order to solve the above problems, one embodiment of the present invention provides a dispersion liquid containing metal oxide particles whose surface is modified with a surface modification material and a hydrophobic solvent,
The surface modification material includes a silane compound and a silicone compound,
The transmission spectrum of the metal oxide particles obtained by drying the dispersion liquid by vacuum drying was measured using a Fourier transform infrared spectrophotometer in the wave number range of 800 cm ^-1 to 3800 cm ^-1 . When the spectrum values are normalized so that the maximum value of the spectrum is 100 and the minimum value is 0, the following formula (1): IA/IB≦3.5 (1)
(In the formula, "IA" indicates the spectral value at 3500 cm ^-1 , and "IB" indicates the spectral value at 1100 cm ^-1 .)
satisfied,
The metal oxide particles are zirconium oxide particles,
The average dispersed particle diameter of the zirconium oxide particles is 10 nm or more and 300 nm or less,
The silane compound is methyltriethoxysilane ,
the silicone compound is a methoxy group-containing phenyl silicone resin,
The content of the silane compound in the dispersion is 50% by mass or more and 500% by mass or less based on the zirconium oxide particles,
The present invention provides a dispersion liquid in which the content of the silicone compound in the dispersion liquid is 50% by mass or more and 500% by mass or less based on the zirconium oxide particles .

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

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

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

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

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

In order to solve the above problems, one embodiment of the present invention includes a step B of mixing a silane compound and metal oxide particles to obtain a mixed liquid;
Step C of dispersing the metal oxide particles in the mixed liquid to obtain a first dispersion liquid in which the metal oxide particles are dispersed;
Step D of adding a hydrophobic solvent to the first dispersion to obtain a second dispersion;
a step E of adding a silicone compound to the second dispersion to obtain a third dispersion;
The content of the metal oxide particles in the mixed solution of 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% by mass or less. % by mass or more and 98% by mass or less,
Step D of adding the hydrophobic solvent is a step d1 of adding the hydrophobic solvent at a rate that does not cause the metal oxide particles to aggregate after heating the first dispersion, while heating the first dispersion; , step d2 of adding the hydrophobic solvent at a rate that does not cause the metal oxide particles to aggregate, or heating the first dispersion after adding the hydrophobic solvent at a rate that does not cause the metal oxide particles to aggregate. In step d3,
The metal oxide particles are zirconium oxide particles,
The average dispersed particle diameter of the zirconium oxide particles is 10 nm or more and 300 nm or less,
The silane compound is methyltriethoxysilane ,
the silicone compound is a methoxy group-containing phenyl silicone resin,
The content of the silane compound in the third dispersion is 50% by mass or more and 500% by mass or less based on the zirconium oxide particles,
A method for producing a dispersion liquid is provided, wherein the content of the silicone compound in the third dispersion liquid is 50% by mass or more and 500% by mass or less based on the zirconium oxide particles .

One aspect of the present invention further includes a step A of mixing the silane compound and water to obtain a hydrolyzed solution containing the hydrolyzed silane compound, and a step B of obtaining the mixed solution, The mixed liquid may be obtained by mixing the hydrolyzed liquid and the metal oxide particles.

As described above, according to the present invention, a dispersion containing metal oxide particles and in which aggregation of the metal oxide particles is suppressed when dispersed in a methyl-based silicone resin, a composition containing the same, and a composition containing the dispersion are provided. A sealing member formed using the present invention, a light-emitting device having the sealing member, a lighting fixture and a display device including the light-emitting device, and a method for producing a dispersion liquid can be provided.

1 is a schematic diagram showing an example of a light emitting device according to an embodiment of the present invention. It is a schematic diagram which shows another example of the light emitting device based on embodiment of this invention. It is a schematic diagram which shows another example of the light emitting device based on embodiment of this invention. It is a schematic diagram which shows another example of the light emitting device based on embodiment of this invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.
<1. Idea of the inventors>
First, prior to a detailed description of the present invention, the ideas that the present inventors and others came up with leading up to the present invention will be explained.

Generally, in manufacturing a sealing material (composition) that is a raw material for a sealing member, metal oxide particles are modified with a surface modification material and dispersed in a resin such as a silicone resin. However, methyl silicone resins have a higher content of methyl groups and a higher degree of hydrophobicity than phenyl silicone resins that have been commonly used in the past. Therefore, even when modified with a surface modification material as described above, it has been difficult to uniformly disperse metal oxide particles in a methyl silicone resin.

Therefore, as a result of intensive studies to solve the problem, the present inventors found that simply increasing the amount of surface modification material used does not significantly improve the dispersibility of metal oxide particles in methyl silicone resin. I found out.

In response to this result, the present inventors conducted further studies and focused on the modification state of the surface modification material on the surface of the metal oxide particles. In other words, even if metal oxide particles are modified using a large amount of surface modification material, if only a small amount of surface modification material is attached to the surface of the metal oxide particles, the surface of the metal oxide particles is not sufficiently hydrophobicized. On the other hand, even if metal oxide particles are modified using a small amount of surface modification material, the adhesion rate of the surface modification material to the surface of metal oxide particles is high, and a large amount of surface modification material is attached to the surface of metal oxide particles. When a surface modification material is attached to the metal oxide particles, the surface of the metal oxide particles is sufficiently hydrophobicized.

The present inventors have determined that when using silane compounds and silicone compounds as surface modification materials, the degree of adhesion of the surface modification materials to metal oxide particles as described above can be determined using a Fourier transform infrared spectrophotometer ( It has been found that it can be measured and observed by FT-IR). It has also been found that the method described below allows a silane compound and a silicone compound to be sufficiently attached to the surface of metal oxide particles, and also has excellent stability over time.

<2. Dispersion>
The dispersion liquid according to this embodiment will be explained. The dispersion liquid according to this embodiment includes metal oxide particles whose surfaces are modified with a silane compound and a silicone compound, and a hydrophobic solvent.

In this embodiment, the transmission spectrum of the metal oxide particles obtained by drying the dispersion liquid by vacuum drying is measured using a Fourier transform infrared spectrophotometer in the wave number range of 800 cm ^-1 to 3800 cm ^-1 . When measuring and normalizing the value of the spectrum so that the maximum value of the spectrum in the range is 100 and the minimum value is 0, the following formula (1):
IA/IB≦3.5 (1)
(In the formula, "IA" indicates the spectral value at 3500 cm ^-1 , and "IB" indicates the spectral value at 1100 cm ^-1 .)
The silane compound is a silicon compound represented by the general formula (2).
R ² _n Si(OR ¹ ) _m (2)
(However, R ¹ is an alkyl group having 2 or more carbon atoms, R ² is an organic group, n and m are integers, n+m=4, 1≦n≦3)

As described above, when the dispersion according to this embodiment is mixed with a methyl-based silicone resin and the metal oxide particles are dispersed in the methyl-based silicone resin, aggregation of the metal oxide particles is suppressed.
As a result, the composition (resin composition) obtained as a mixture is suppressed from turbidity and becomes relatively transparent.
Furthermore, since R ¹ is an alkyl group having 2 or more carbon atoms, it is possible to suppress an increase in viscosity over time of a composition obtained by mixing the dispersion according to the present embodiment with a methyl silicone resin. .

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

The present inventors have also found that when IA/IB is 3.5 or less, the silane compound and silicone compound are sufficiently attached to the surface of the metal oxide particles. This allows the metal oxide particles to be dispersed in the methyl silicone resin without agglomerating when mixed with the methyl silicone resin. As a result, the composition obtained as a mixture has less turbidity and is relatively transparent. Furthermore, since metal oxide particles are contained, when a sealing member for sealing a light emitting element is obtained using the composition, the refractive index of the sealing member is lower than that of the methyl silicone resin alone. It's improved compared to the previous one. As described above, when a composition is obtained using the dispersion liquid according to the present embodiment and a light emitting element is sealed using the composition, the light emitting device brightness is improved.

On the other hand, when IA/IB exceeds 3.5, the silane compound and the silicone compound are not sufficiently attached to the surface of the metal oxide particles, and the metal oxide particles are dispersed in the methyl silicone resin. It is not possible to make one's sexuality superior. As a result, when the dispersion liquid and the methyl-based silicone resin are mixed, the metal oxide particles agglomerate and the resulting composition becomes cloudy. As mentioned above, IA/IB is 3.5 or less, preferably 3.0 or less, more preferably 2.5 or less, and even more preferably 2.0 or less.

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

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

Furthermore, in this embodiment, a silicon compound represented by general formula (2) is used as the silane compound. The reason is as follows.
When metal oxide particles are surface-treated with a silane compound having a hydrolyzable group (OR group), the OR group is hydrolyzed to become an OH group or remains as an OR group. If this remaining OR group is easily hydrolyzed, even after surface treatment, the remaining OR group will react with moisture in the air and be hydrolyzed, leading to dehydration condensation between silane compounds and between silane compounds and silicone compounds. It is assumed that the reaction progresses. As a result, the viscosity of such a mixture of surface-modified metal oxide particles and resin tends to increase, resulting in poor stability over time.
However, in this embodiment, R ¹ is an alkyl group having two or more carbon atoms, so even if ^one OR group remains on the surface of the metal oxide particles, the hydrolysis reaction with moisture in the air is suppressed, Increase in viscosity of dispersion liquid etc. can be suppressed. Therefore, the dispersion liquid of this embodiment has excellent stability over time.

If the (OR ¹ ) groups are all hydrolyzed and all bonded to the surface of the metal oxide particle, there is no problem even if the number of carbon atoms in the OR ¹ group is 1, but it is not easy to achieve such a surface treatment. Therefore, by using the silane compound represented by the general formula (2), the stability over time of the dispersion liquid etc. can be improved even if ^one OR group remains.

The dispersion liquid of this embodiment and methylphenyl silicone (methyl silicone resin) are combined in a mass ratio of the total mass of metal oxide particles and surface modification materials (silane compound and silicone compound) to methylphenyl silicone: It is preferable that the viscosity after removing the hydrophobic solvent is 9 Pa·s or less.
The methylphenyl silicone is KER-2500-B manufactured by Shin-Etsu Chemical Co., Ltd.
The lower limit of viscosity is the viscosity of KER-2500-B itself, but the above viscosity may be, for example, 1 Pa.s or more, 2 Pa.s or more, or 3 Pa.s or more. It's okay.

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

When the hydrophobic solvent is removed, the particles come close to each other, and the viscosity of the composition (composition containing metal oxide particles, surface modification material, and methyl silicone resin) increases. Therefore, the viscosity after removing the hydrophobic solvent means the viscosity of the composition measured within 1 hour after removing the hydrophobic solvent from the dispersion.

When the viscosity is 9 Pa·s or less, the viscosity of the composition after mixing the methylphenyl silicone and the dispersion and removing the hydrophobic solvent increases slowly, making it easy to handle the composition. The quality stability of the sealing member can be improved.

The dispersion liquid of this embodiment and methylphenyl silicone are mixed so that the mass ratio of the total mass of metal oxide particles and surface modification material to methylphenyl silicone is 30:70, and the hydrophobic solvent is removed. It is preferable that the viscosity after one month has passed is 60 Pa·s or less.
If the viscosity after one month is 60 Pa·s or less, the dehydration condensation reaction of the silane compound after surface treatment is suppressed, and the level is sufficient for practical use.
The viscosity after one month is more preferably 50 Pa·s or less, and even more preferably 40 Pa·s or less.

The knowledge that stability over time can be improved by achieving the above-mentioned IA/IB value for metal oxide particles and using a silicon compound represented by general formula (2) as a silane compound, Until now, the present inventors have discovered that this can be achieved for the first time by the method described below.

Each component contained in the dispersion will be explained below.

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

The metal oxide particles contained in the dispersion according to this embodiment are not particularly limited. In this embodiment, examples of metal oxide particles include zirconium oxide particles, titanium oxide particles, zinc oxide particles, iron oxide particles, copper oxide particles, tin oxide particles, cerium oxide particles, tantalum oxide particles, niobium oxide particles, Tungsten oxide particles, europium oxide particles, yttrium oxide particles, molybdenum oxide particles, indium oxide particles, antimony oxide particles, germanium oxide particles, lead oxide particles, bismuth 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 tungstate 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, Ytterbia-stabilized zirconia particles, ceria-stabilized zirconia particles, india-stabilized zirconia particles, strontium-stabilized zirconia particles, samarium oxide-stabilized zirconia particles, gadolinium oxide-stabilized zirconia particles, antimony-doped tin oxide particles Metal oxide particles containing at least one selected from the group consisting of , and indium-doped tin oxide particles are preferably used.

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

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

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

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 diameter of the metal oxide particles is 10 nm or more, the brightness of light of a light-emitting device manufactured using this dispersion, which will be described later, is improved. Furthermore, by setting the average dispersed particle size of the metal oxide particles to 300 nm or less, it is possible to suppress a decrease in the light transmittance of the dispersion liquid, a composition described below manufactured using the same, and a sealing member. . As a result, the brightness of the light from the light emitting device is improved.

Note that the average dispersed particle diameter of the metal oxide particles can be the particle diameter 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 using a scattering particle size distribution analyzer (for example, manufactured by HORIBA, model number: SZ-100SP). The measurement can be performed using a quartz cell with an optical path length of 10 mm x 10 mm for a dispersion liquid whose solid content is adjusted to 5% by mass. In addition, in this specification, "solid content" refers to the residue when volatile components are removed from the dispersion liquid. For example, when 1.2 g of the dispersion is placed in a magnetic crucible and heated on a hot plate at 100°C for 1 hour, the components that remain without volatilizing (metal oxide particles, surface modification materials, etc.) are considered solid content. be able to.

In addition, the average dispersed particle diameter of metal oxide particles is determined by the diameter of the dispersed metal oxide particles, regardless of whether the metal oxide particles are dispersed as primary particles or secondary particles. Measured and calculated based on Furthermore, in the present embodiment, the average dispersed particle size of the metal oxide particles may be measured as the average dispersed particle size of the metal oxide particles to which the surface modification material is attached. In the dispersion, there may be metal oxide particles to which the surface modification material is attached and metal oxide particles to which the surface modification material is not attached, so the average dispersed particle diameter of the metal oxide particles is usually It is measured as a value in a mixed state of these.

The average primary particle diameter 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 even more preferably 10 nm or more and 100 nm or less. When the average primary particle diameter of the metal oxide particles is within the above range, a decrease in transparency of the sealing member can be suppressed. As a result, the brightness of the light from the light emitting device can be further improved.

The average primary particle diameter of metal oxide particles can be measured, for example, by observation with a transmission electron microscope. First, a collodion film containing metal oxide particles collected from a dispersion liquid is observed using a transmission electron microscope to obtain a transmission electron microscope image. Next, a predetermined number, for example 100, of metal oxide particles in the transmission electron microscope image are selected. Then, the longest straight line segment (maximum major axis) of each of these metal oxide particles is measured, and the measured values are calculated by arithmetic averaging.

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

Further, the content of metal oxide particles in the dispersion is not particularly limited as long as they can be mixed with the resin component described below. The content of metal oxide particles in the dispersion 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 is more preferable.

This makes it possible to prevent the viscosity of the dispersion liquid from becoming excessively large, thereby facilitating mixing with the resin component described below. Further, it is possible to prevent the amount of solvent (dispersion medium) from becoming excessive after mixing with the resin component, and the removal of the solvent becomes easy.

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

(2.2 Surface modification material)
The dispersion liquid according to this embodiment contains a silane compound and a silicone compound as surface modification materials. Furthermore, the silane compound is represented by general formula (2).
Only silane compounds and silicone compounds may be used as surface modification materials.
At least a portion of this surface modification material adheres to the surface of the metal oxide particles in the dispersion and modifies the surface, thereby preventing agglomeration of the metal oxide particles. Furthermore, the compatibility with the resin component is improved.

Here, the surface modification material "adheres" to the metal oxide particles means that the surface modification material contacts or bonds to the metal oxide particles through interaction or reaction between them. Examples of contact include physical adsorption. Further, examples of the bond include an ionic bond, a hydrogen bond, and a covalent bond.

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

Silane compounds tend to adhere to the vicinity of the surfaces of metal oxide particles. On the other hand, the silicone compound has a relatively large molecular weight and mainly contributes to improving the affinity with the dispersion medium and the resin component described below. By using such a silane compound and a silicone compound in combination, the dispersion stability of metal oxide particles in a methyl silicone resin is improved.

On the other hand, if the dispersion liquid does not contain either the silane compound or the silicone compound, the above-mentioned effects cannot be obtained. For example, if the dispersion liquid does not contain a silane compound, the silicone compound will be difficult to adhere to the surface of the metal oxide particles, and the dispersibility of the metal oxide particles in the methyl silicone resin will be poor. On the other hand, if the dispersion liquid does not contain a silicone compound, the affinity between the metal oxide particles and the methyl silicone resin will not be sufficiently large, and the dispersibility of the metal oxide particles in the methyl silicone resin will be poor. Become.

The silane compound is represented by general formula (2).
R ² _n Si(OR ¹ ) _m (2)
R ² is not particularly limited as long as it is an organic group, and one that has good compatibility with the resin described below may be selected. Examples of R ² include an alkyl group having 1 to 6 carbon atoms, a phenyl group, a vinyl group, and a (meth)acryloyl group. Among these, an alkyl group having 1 to 4 carbon atoms is more preferable, an alkyl group having 1 to 3 carbon atoms is more preferable, and an alkyl group having 1 to 2 carbon atoms is more preferable because it easily adheres to metal oxide particles. is even more preferred, and a methyl group having 1 carbon number is most preferred.

R ¹ is an alkyl group having 2 or more carbon atoms. The number of carbon atoms may be selected in consideration of the balance between ease of surface modification and stability over time, and is preferably 2 or more and 6 or less, more preferably 2 or more and 5 or less, and 2 or more. It is more preferably 4 or more, even more preferably 2 or more and 3 or less, and most preferably 2.

As described above, since (OR ¹ ) is a hydrolyzable group, a portion of R ¹ may be H.
After the surface treatment reaction, (OR ¹ ) is bonded to the metal oxide particles or remains on the surface of the metal oxide particles as OR ¹ or OH. Although it is preferable that OH does not remain, it is difficult to completely remove it, so a small amount may remain as long as formula (1) is satisfied.

n is 1 or more and 3 or less, more preferably 1 or more and 2 or less, and even more preferably 1.
m is 1 or more and 3 or less, more preferably 2 or more and 3 or less, and even more preferably 3.

Examples of silane compounds satisfying general formula (2) include methyltriethoxysilane, methyltripropoxysilane, ethyltriethoxysilane, and alkyl groups such as ethyltripropoxysilane, isobutyltriethoxysilane, and methylphenyldiethoxysilane. Silane compounds containing alkoxy groups, silane compounds containing alkenyl groups and alkoxy groups such as vinyltriethoxysilane, methacryloxypropyltriethoxysilane, acryloxypropyltriethoxysilane, diethoxymonomethylsilane, monoethoxydimethylsilane, diphenylmonoethoxy Silane compounds containing H-Si groups and alkoxy groups such as silane, other silane compounds containing alkoxy groups such as phenyltriethoxysilane, and silanes containing H-Si groups such as triethoxysilane, diethoxysilane, and monoethoxysilane. Examples include compounds. These silane compounds may be used alone or in combination of two or more. Among these, silane compounds having an alkoxy group, particularly an ethoxy group, are preferred because they tend to adhere to metal oxide particles.

Such surface modification material preferably contains at least one selected from the group consisting of methyltriethoxysilane, methyltripropoxysilane, ethyltriethoxysilane, and ethyltripropoxysilane, and methyltriethoxysilane is It is more preferable to use it.

The content of the silane compound in the dispersion is not particularly limited, but is preferably, for example, 50% by mass or more and 500% by mass or less, and 70% by mass or more and 400% by mass or less, based on the metal oxide particles. It is more preferably 90% by mass or more and 300% by mass or less. This allows a sufficient amount of the silicone compound to be attached to the surface of the metal oxide particles via the silane compound, improving the dispersion stability of the metal oxide particles and improving the dispersibility in the methyl silicone resin. can be improved.

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

Among the above, from the viewpoint of ease of reaction and high hydrophobicity, the silicone compound is preferably alkoxy group-containing phenyl silicone, dimethyl silicone, methylphenyl silicone, alkoxy-terminated phenyl silicone, alkoxy-terminated methylphenyl silicone, Contains at least one selected from the group consisting of alkoxy group-containing methylphenyl silicone, alkoxy group-containing dimethyl silicone, alkoxy one end trimethyl end (methyl group one end) dimethyl silicone, and alkoxy group containing phenyl silicone, 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, for example, 50% by mass or more and 500% by mass or less, and 80% by mass or more and 400% by mass or less, based on the metal oxide particles. It is more preferably 100% by mass or more and 300% by mass or less. This allows a sufficient amount of the silicone compound to adhere to the surface of the metal oxide particles, improving the dispersion stability of the metal oxide particles and improving the dispersibility in the methyl silicone resin. can. Furthermore, the amount of liberated silicone compounds can be reduced, and unwanted aggregation of metal oxide particles in the methyl silicone resin can be suppressed.

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

The amount of the surface modification material relative 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 150% by mass or more. It is more preferably 800% by mass or less, and even more preferably 190% by mass or more and 600% by mass or less. When the amount of the surface modification material is within the above range, the dispersibility of the metal oxide particles can be sufficiently improved while reducing the amount of the surface modification material released.

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

Furthermore, the hydrophobic solvent is preferably an aromatic compound, particularly an aromatic hydrocarbon. Aromatics have excellent compatibility with the methyl-based silicone resin described below, and thereby contribute to improving the viscosity characteristics of the resulting composition and the quality (transparency, shape, etc.) of the formed sealing member.

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

Among the above-mentioned hydrophobic solvents, 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 liquid may be adjusted as appropriate to obtain 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 below, especially the methyl silicone resin.

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

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

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

From the viewpoint of having excellent affinity with both water and a hydrophobic solvent and promoting the mixing thereof, the hydrophilic solvent preferably includes an alcohol solvent. In this case, the number of carbon atoms in the alcohol compound constituting the alcohol solvent is preferably 1 or more and 3 or less, more preferably 1 or more and 2 or less.
Among the above-mentioned, methanol and ethanol, particularly methanol, can be preferably used because it can sufficiently exhibit the effects of the alcohol solvent.

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

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

Note that, in this 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 below to the extent that a sealing member can be formed even if it is simply cured. More specifically, the mass ratio of the resin component to the metal oxide particles in the dispersion according to the present embodiment may be in the range of 0:100 to 40:60 (resin component: metal oxide particles). The ratio is preferably in the range of 0:100 to 20:80. The dispersion liquid according to the present embodiment preferably does not essentially contain the resin component described below, and particularly preferably does not contain the resin component described below completely.

In the dispersion liquid according to this 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 manner have excellent affinity with the methyl silicone resin and can be dispersed relatively uniformly in the methyl silicone resin. Therefore, even when metal oxide particles are dispersed in the methyl silicone resin, the occurrence of cloudiness such as cloudiness is suppressed. Furthermore, changes in the viscosity of the methyl silicone resin containing metal oxide particles are also suppressed.

<3. Dispersion manufacturing method>
Next, a method for producing a dispersion liquid according to this embodiment will be explained.

The method for producing a dispersion liquid according to the present embodiment includes a step B of mixing a silane compound and metal oxide particles to obtain a mixed liquid;
Step C of dispersing the metal oxide particles in the mixed liquid to obtain a first dispersion liquid in which the metal oxide particles are dispersed;
Step D of adding a hydrophobic solvent to the first dispersion to obtain a second dispersion;
a step E of adding a silicone compound to the second dispersion to obtain a third dispersion;
The content of the metal oxide particles in the mixed solution of step B is 10% by mass or more and 49% by mass or less, and the total content of the surface modification material and the metal oxide particles in the mixed solution is 65% by mass or more and 98% by mass or less,
Step D of adding the hydrophobic solvent is a step d1 of adding the hydrophobic solvent at a rate that does not cause the metal oxide particles to aggregate after heating the first dispersion, while heating the first dispersion; , step d2 of adding the hydrophobic solvent at a rate that does not cause the metal oxide particles to aggregate, or heating the first dispersion after adding the hydrophobic solvent at a rate that does not cause the metal oxide particles to aggregate. In step d3, the silane compound is a silicon compound represented by general formula (2).
R ² _n Si(OR ¹ ) _m (2)
(However, R ¹ is an alkyl group having 2 or more carbon atoms, R ² is each independently an organic group, n and m are integers, n+m=4, 1≦n≦3)

Note that the total content of the silane compound and the metal oxide particles can also be evaluated based on 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, which will be described later. That is, the total content of the silane compound and the metal oxide particles means the total content of the silane compound, the hydrolyzed silane compound, and the metal oxide particles. It goes without saying that the above total content includes the content of metal oxide particles attached to the silane compound.

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

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

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

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

Moreover, in the hydrolysis step, the hydrolysis liquid contains water. Water serves as a substrate for the hydrolysis reaction of surface modification materials such as silane compounds.
The content of water in the hydrolysis solution is not particularly limited, and can be appropriately set, for example, depending on the amount of the silane compound. For example, the amount of water added to the hydrolysis solution is preferably 0.5 mol or more and 5 mol or less, more preferably 0.6 mol or more and 3 mol or less, and 0.7 mol or less, per 1 mol of the silane compound. More preferably, the amount is 2 mol or less. This makes it possible to sufficiently advance the hydrolysis reaction of the silane compound while more reliably preventing agglomeration of metal oxide particles in the dispersion produced using an excessive amount of water.

Alternatively, the content of water in the hydrolysis solution is, for example, preferably 1% by mass or more and 20% by mass or less, more preferably 1% by mass or more and 15% by mass or less, and 1% by mass or more and 10% by mass. % or less is more preferable.

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

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

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

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

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

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

Examples of such hydrophilic solvents include various hydrophilic solvents that can be included in the above-mentioned dispersion.

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

Further, the content of the hydrophilic solvent in the hydrolysis solution is not particularly limited, but is preferably, for example, 60% by mass or less, and more preferably 50% by mass or less. Thereby, the contents of the silane compound and water in the hydrolysis liquid can be sufficiently increased. Further, the content of the hydrophilic solvent in the hydrolyzate is, for example, preferably 10% by mass or more, more preferably 15% by mass or more. Thereby, the mixing of the surface modification material and water can be further promoted, and as a result, the hydrolysis reaction of the surface modification material can proceed efficiently. Note that the hydrolysis solution may not contain any hydrophilic solvent other than the compound derived from the hydrolysis reaction.

In this embodiment, since a silane compound having an alkoxy group is hydrolyzed, an alcohol compound derived from an alkoxy group is contained in the liquid mixture. Since the hydrolysis reaction also proceeds with water adsorbed by metal oxide particles, it can occur in any of Steps A to E. Therefore, unless there is a step of removing alcohol compounds, the resulting dispersion will contain alcohol compounds.

In the hydrolysis step, the hydrolyzate may be maintained at a constant temperature for a predetermined period of time after being prepared. Thereby, the hydrolysis of the silane compound can be further promoted.
In this treatment, the temperature of the hydrolysis solution is not particularly limited and can be changed as appropriate depending on the type of silane compound, but for example, it is preferably 5°C or more and 65°C or less, and preferably 30°C or more and 60°C or less. More preferred.

Further, the holding time is not particularly limited, but for example, it is preferably 10 minutes or more and 180 minutes or less, and more preferably 30 minutes or more and 120 minutes or less.
In addition, in holding the above-mentioned hydrolyzed liquid, the hydrolyzed liquid may be appropriately stirred.

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

The content of metal oxide particles in the mixed liquid is 10% by mass or more and 49% by mass or less, and the total content of the silane compound and metal oxide particles is 65% by mass or more and 98% by mass or less. Then, mixing is performed.

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

To explain in detail, when metal oxide particles are generally surface-modified with a surface-modifying material in a liquid phase, a mixed liquid is obtained by mixing not only the metal oxide particles and the surface-modifying material but also a dispersion medium. Generally, liquids are dispersed using a dispersion machine. Here, when such surface-modified metal oxide particles are mixed with a methyl-based silicone resin, they cannot be sufficiently dispersed in the methyl-based silicone resin and agglomerate, and as a result, the methyl-based silicone resin There is a problem that turbidity such as white clouding occurs. In such a case, the metal oxide particles added do not fully exhibit the desired performance.

The dispersion medium is usually added for the purpose of lowering the viscosity of the liquid mixture, uniformly dispersing the metal oxide particles, and causing the surface modification material to uniformly modify the surface of the metal oxide particles. Conventionally, it has been thought that when a dispersion medium is not used, the viscosity of the dispersion liquid increases, and as a result, the surface modification material does not adhere sufficiently to the surface of the metal oxide particles. Surprisingly, the present inventors have succeeded in dispersing metal oxide particles directly into a highly concentrated silane compound, without using such a dispersion medium, which was previously thought to be essential, or using only a small amount. It has been found that by doing so, the metal oxide particles can be uniformly dispersed in the resulting dispersion, and the metal oxide particles can be uniformly modified with the silane compound.

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

If the total content of the silane compound and metal oxide particles is less than 65% by mass, components other than the above two components, such as dispersion medium, will be too large, and the silane compound will not be added in the dispersion step (step C) described below. It cannot be sufficiently attached to the surface of metal oxide particles. As a result, many hydroxyl groups remain on the surface of the metal oxide particles, and when the resulting dispersion is mixed with a hydrophobic material, the metal oxide particles aggregate, causing turbidity in the hydrophobic material. . The total content of the silane compound and metal oxide particles may be 65% by mass or more, preferably 70% by mass or more, and more preferably 75% by mass or more.

On the other hand, if the total content of the silane compound and metal oxide particles exceeds 98% by mass, the viscosity of the liquid mixture will become too high, and the silane compound will not be sufficiently absorbed in the dispersion step (step C) described below. It cannot be attached to the surface of metal oxide particles. The total content of the silane compound and metal oxide particles may be 98% by mass or less, preferably 97% by mass or less, and more preferably 95% by mass or less.

Further, as described above, the content of metal oxide particles in the mixed liquid is 10% by mass or more and 49% by mass or less. This makes it possible to keep the amount of silane compound to the metal oxide particles within an appropriate range, allowing the silane compound to adhere uniformly to the surface of the metal oxide particles, and suppressing an increase in the viscosity of the mixed liquid. can do.

On the other hand, if the content of metal oxide particles in the mixed solution is less than 10% by mass, the amount of silane compound will be excessive with respect to the metal oxide particles, and the excess silane compound will be present in the resulting dispersion. Induces agglomeration of metal oxide particles. The content of metal oxide particles in the liquid mixture is preferably 20% by mass or more, more preferably 30% by mass or more.

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

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

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

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

The content of the organic solvent in the mixed liquid is not particularly limited as long as the content of the metal oxide particles and the silane compound described above is satisfied. Note that it goes without saying that the mixed liquid does not need to contain an organic solvent.

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

Dispersion of metal oxide particles can be performed using a known disperser. As the dispersing machine, for example, a bead mill, a ball mill, a homogenizer, a disperser, a stirrer, etc. are suitably used.

In the dispersion process, the metal oxide particles in the dispersion are mixed by applying the minimum amount of energy without applying excessive energy so that the particle size (dispersed particle size) is almost uniform. It is preferable to disperse the metal oxide particles in the liquid.

(Step D (addition step (first addition step)))
In the addition step, a hydrophobic solvent is added to the first dispersion liquid, and the dispersion liquid is adjusted to a desired solid content (concentration).
The first dispersion obtained in the dispersion step has a high solid content (concentration), so it has a high viscosity and poor handling properties. However, when a hydrophobic solvent is added to the obtained first dispersion in order to lower the solid content, the particles aggregate due to the low hydrophobicity of the particle surface, making it impossible to obtain a uniform dispersion. Ta.

Therefore, the present inventors have also discovered that by heating the obtained first dispersion liquid and gradually adding a hydrophobic solvent, it is possible to adjust the dispersion liquid to a low solid content.

The mechanism is presumed as follows.
By heating the dispersion liquid, polymerization of the silane compound attached to the metal oxide particles progresses, and the hydrophobicity of the particle surface improves. Even if the polymerization reaction progresses too much, the metal oxide particles will aggregate, so by gradually adding a hydrophobic solvent to the dispersion while the polymerization reaction is in progress, the surface will gradually change while suppressing the excessive polymerization reaction. Hydrophobized and hydrophobic solvents can be gradually mixed.

That is, by adding a hydrophobic solvent in an amount that does not cause the metal oxide particles to aggregate, and allowing the polymerization reaction of the silane compound to proceed to an extent that the silane compound is compatible with the added amount of hydrophobic solvent, the desired solid content is achieved. A controlled dispersion can be obtained.

As mentioned above, the hydrophobic solvent may be added gradually to prevent the metal oxide particles from agglomerating. Therefore, the hydrophobic solvent may be added after the first dispersion is heated, or the first dispersion may be heated after the hydrophobic solvent is added, and the heating of the first dispersion and Addition of the hydrophobic solvent may be carried out at the same time.
That is, the addition step may be a step d1 of heating the first dispersion and then adding the hydrophobic solvent at a rate that does not cause the metal oxide particles to aggregate. Step d2 may include adding the hydrophobic solvent at a rate that does not cause the metal oxide particles to aggregate while heating the liquid, or adding the hydrophobic solvent at a rate that does not cause the metal oxide particles to aggregate. After the addition, step d3 may include heating the first dispersion.

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

For example, the hydrophobic solvent may be added stepwise every 30 minutes, every 1 hour, or every 2 hours so that the solid content is reduced in the range of 3% by mass to 20% by mass. If the heating temperature is high, increase the amount of hydrophobic solvent added at one time, and if the heating temperature is low, reduce the amount of hydrophobic solvent added at one time. may be adjusted accordingly.

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

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

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

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

Among these, aromatic hydrocarbons include toluene, o-xylene, and m-xylene from the viewpoint of stability of the dispersion liquid and ease of handling in removing the dispersion medium during composition production, which will be described later. At least one selected from the group consisting of , p-xylene and benzene is particularly preferably used.

The content of the hydrophobic solvent contained in the final dispersion may be adjusted as appropriate so as to provide a desired solid content. The content of the hydrophobic solvent is, for example, preferably 40% by mass or more and 95% by mass or less, more preferably 50% by mass or more and 90% by mass or less, and 60% by mass or more and 80% by mass or less. is even more preferable.
Through the first addition step, a second dispersion liquid having a desired solid content is obtained. By using the second dispersion liquid, the handling properties of the dispersion liquid in the following steps are improved.

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

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

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

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

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

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

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

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

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

In the dispersion produced using the dispersion production method according to the present embodiment, the metal oxide particles are uniformly dispersed, and the surfaces of the metal oxide particles are uniformly and sufficiently modified with the silane compound and the silicone compound. ing. The metal oxide particles modified in this manner have excellent affinity with the methyl silicone resin and can be dispersed relatively uniformly in the methyl silicone resin. Therefore, even when metal oxide particles are dispersed in the methyl silicone resin, the occurrence of cloudiness such as cloudiness is suppressed. Furthermore, changes in the viscosity of the methyl silicone resin containing metal oxide particles are also suppressed.

Note that the dispersion according to the present embodiment may contain components other than those mentioned above, such as a dispersant, a dispersion aid, an antioxidant, a fluidity regulator, a thickener, a pH regulator, a preservative, etc., as necessary. General additives and the like may be mixed. These are added at any step as necessary.

As described above, the dispersion liquid of this embodiment allows the metal oxide particles to be mixed with the hydrophobic material by directly dispersing the metal oxide particles in the silane compound. It is presumed that more silane compounds adhere to metal oxide particles than in conventional dispersions, and a dense coating is formed. However, it is unclear what condition the surface of the metal oxide particles is in that allows the dispersion to mix with the hydrophobic material. Therefore, it is impossible to directly specify the characteristics of the dispersion liquid of this embodiment based on the state of the surface of the metal oxide particles modified with the silane compound and the silicone compound. Considering that the dispersion includes metal oxide particles, one or more silane compounds and one or more silicone compounds at least partially attached to the metal oxide particles, and a hydrophobic solvent, the metal oxide particles The categorical specification of the surface conditions that enable the particles to be mixed with hydrophobic materials means that the ability of metal oxide particles to mix with hydrophobic materials is due to the structure and structure of silane and silicone compounds. Considering that this is thought to be caused by a complex interplay 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, this is almost impossible. .

<4. Composition>
Next, the composition according to this embodiment will be explained.
The composition according to this embodiment is a mixture of the above-described dispersion and a resin component. Therefore, the composition according to the present embodiment includes a resin component, that is, at least one of 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 below and used as a sealing member for a light emitting device. The composition according to the present embodiment can improve the brightness of light from a light emitting device when used in a sealing member by containing the metal oxide particles that contribute to improving the refractive index and transparency described above. can.

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

From the viewpoint of obtaining a highly transparent composition, the content of 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. It is more preferably the following, and even more preferably 10% by mass or more and 35% by mass or less.

Further, the content of the surface modification material such as a silane compound and a 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 this embodiment. When the composition according to this embodiment is used as a sealing material, the resin component cures and seals the light emitting element, thereby preventing deterioration factors from the external environment such as moisture and oxygen from reaching the light emitting element. prevent. Furthermore, in this embodiment, the cured product obtained from the resin component is basically transparent and can transmit light emitted from the light emitting element.

Such a resin component is not particularly limited as long as it can be used as a sealing material. For example, resins such as silicone resin and epoxy resin may be used alone or in combination of two or more. It's okay. In particular, from the viewpoint of durability, silicone resins, particularly methyl silicone resins, are preferred.

As the methyl silicone resin, for example, dimethyl silicone resin, methylphenyl silicone resin, etc. can be used.

The content of the methyl silicone resin in the resin component may be adjusted according to the desired properties and is not particularly limited, and may be, for example, 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, or it may be 40% by mass or more and 60% by mass or less. Conventionally, when metal oxide particles were contained in a methyl silicone resin, the metal oxide particles agglomerated, resulting in decreased transparency and insufficient improvement in refractive index. 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 the composition contains such a large amount of methyl-based silicone resin as a resin component, Even in this case, agglomeration of metal oxide particles is suppressed, and a decrease in transparency is suppressed. On the other hand, since it becomes possible to employ a methyl-based silicone resin, the durability of the sealing member formed using the composition is improved.

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

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

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

The composition according to this embodiment may contain the dispersion medium derived from the dispersion according to this embodiment, or may be removed. That is, the dispersion medium derived from the dispersion liquid may be completely removed, or it may remain in the composition at about 1% by mass or more and 10% by mass or less, or about 2% by mass or more and at most 5% by mass. Good too.

Further, the composition according to the present embodiment may contain phosphor particles within a range that does not impede the object of the present invention. The phosphor particles absorb light of a specific wavelength emitted from the light emitting element and emit light of a predetermined wavelength. That is, the phosphor particles make it possible to convert the wavelength of light and 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 below, and can be appropriately selected and used so that the emitted light color of the light emitting device becomes a desired color.
The content of phosphor particles in the composition of this embodiment can be adjusted as appropriate so as to obtain desired brightness.

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

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

Since the composition according to the present embodiment includes metal oxide particles surface-modified with the above-mentioned silane compound and silicone compound, even if a methyl-based silicone resin is included as a resin component, the metal oxide particles aggregation is suppressed, and a decrease in transparency is suppressed. Therefore, the composition according to this embodiment can be used to form a sealing member that improves the brightness of light from a light-emitting device.

<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 this embodiment is usually used as a sealing member placed on a light emitting element or as a part thereof.
The thickness and shape of the sealing member according to this embodiment can be adjusted as appropriate depending on the desired use and characteristics, and are not particularly limited.

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

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

Note that the average dispersed particle diameter of the metal oxide particles in the sealing member is the average particle diameter (median diameter) based on the number distribution, which is measured by transmission electron microscopy (TEM) of the sealing member. Further, 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 metal oxide particles in the dispersed state, regardless of whether the metal oxide particles are dispersed as primary particles or secondary particles. . Moreover, in this embodiment, the average particle diameter of the metal oxide particles in the sealing member may be measured as the average particle diameter of the metal oxide particles to which the surface modification material described below is attached. In the sealing member, there may be metal oxide particles to which the surface modification material is attached and metal oxide particles to which the surface modification material is not attached. The average particle diameter is measured as a value in a mixed state of these particles.

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

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

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

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

The light emitting device (LED package) 1A shown in FIG. A sealing member 4A is provided for sealing.
The sealing member 4A is constituted by the sealing member 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. Furthermore, phosphor particles 5 are dispersed within the sealing member 4A. The phosphor particles 5 convert the wavelength of at least a portion of the light emitted from the light emitting element 3.

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

The light emitting device 1C shown in FIG. 3 also differs from the light emitting device 1A in that the configuration of the sealing member 4C is different from that of the sealing member 4A. The sealing member 4C has a first layer 41C that directly covers the light emitting element 3, and a second layer 43C that covers the first layer 41C. The first layer 41C is not the sealing member according to this embodiment, but is a resin sealing member that does not contain the metal oxide particles described above, and is made of a resin or the like that can be used for the sealing member. . Furthermore, the phosphor particles 5 are dispersed within the first layer 41C. On the other hand, the second layer 43C is a sealing member according to this 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 includes a first layer 41D that directly covers the light emitting element 3, a second layer 43D that covers the first layer 41D, and a second layer 43D that further covers the second layer 43D. It has a third layer 45D. The first layer 41D and the second layer 43D are not the sealing member according to the present embodiment, but are resin sealing members that do not contain the metal oxide particles described above, and are resins that can be used for the sealing member. It is composed of etc. Further, within the second layer 43D, phosphor particles 5 are dispersed. On the other hand, the third layer 45D is a sealing member according to this 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.

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

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

Further, in the light emitting device according to the present embodiment, the light emitting element is sealed with 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, which includes a step of sealing a light-emitting element using the composition according to the present embodiment. In the same aspect, the manufacturing method may include a step of mixing the dispersion according to the present embodiment and a resin component to obtain the composition.

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

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

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

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

[Example 1]
(1. Preparation of dispersion liquid)
(i) Hydrolysis step 90.78 parts by mass of methyltriethoxysilane (manufactured by Shin-Etsu Kogyo Chemical Co., Ltd., product name KBE-13), 9.21 parts by mass of water, and 0.01 parts by mass of hydrochloric acid (1N). The mixture was added and mixed to obtain a hydrolyzed solution. Next, this hydrolyzed solution was stirred at 60° C. for 30 minutes to perform a hydrolyzing treatment of methyltriethoxysilane to obtain a hydrolyzed solution.

(ii) Mixing Step 30 parts by mass of zirconium oxide 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 liquid is 30% by mass, the content of methyltriethoxysilane is 63.5% by mass, and the total content of zirconium oxide particles and methyltriethoxysilane is 93.5% by mass. there were.

(iii) Dispersion process After dispersing this liquid mixture in a bead mill for 6 hours, the beads were removed to obtain a first dispersion liquid.
The solid content of the first dispersion was measured (at 100° C. for 1 hour) and found to be 70% by mass.

(iv) First addition step The obtained first dispersion liquid 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.

(v) 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 11.9 parts by mass of methoxy group-containing phenyl silicone resin (manufactured by Shin-Etsu Chemical Co., Ltd., KR217) Part by mass was mixed to obtain a treatment liquid, and this treatment liquid was heated at 110° C. for 1 hour to obtain a dispersion according to Example 1 (third dispersion).

(2. Evaluation of dispersion liquid)
(i) Particle size distribution A part of the obtained dispersion according to Example 1 was collected, and the solid content was adjusted to 5% by mass with toluene. Measurement was performed using a meter (manufactured by HORIBA, model number: SZ-100SP). As a result, D10 was 110 nm, D50 was 135 nm, and D90 was 150 nm. In addition, since the particles contained in the dispersion are basically only zirconium oxide particles to which a surface modification material (methyltriethoxysilane, methoxy group-containing phenyl silicone resin) is attached, the measured D10, D50, and D90 are as follows. D10, D50 and D90 of zirconium oxide particles were considered.

(ii) FT-IR analysis 10 g of the dispersion according to Example 1 whose solid content was adjusted to 30% by mass with toluene was dried using a vacuum dryer (EYELA Tokyo Rikakiki Co., Ltd., device name: VACUUM OVEN VOS-201SD). , 100° C., and 20 hPa for 2 hours. Next, using 0.01 g to 0.05 g of the obtained metal oxide particles, a measurement of 800 cm ^-1 or more was performed using a Fourier transform infrared spectrophotometer (manufactured by JASCO Corporation, model number: FT/IR-670 Plus). The transmission spectrum in the wavenumber range of 3800 cm ⁻¹ or less was measured. The spectral values were normalized so that the maximum value of the spectrum in this measurement range was 100 and the minimum value was 0, and the value at 3500 cm ^-1 (IA) and the value at 1100 cm ^-1 (IB) were determined. As a result, IA was 51.5, IB was 26.5, and IA/IB was 1.9. The results are shown in Table 1.

(3. Preparation of composition)
5.0 g of the dispersion according to Example 1 whose solid content was adjusted to 30% by mass with toluene and 3.5 g of methylphenyl silicone (trade name: KER-2500-B, manufactured by Shin-Etsu Chemical Co., Ltd.) were mixed. That is, the total mass of zirconia and surface modification material and methylphenyl silicone were mixed in a mass ratio of 30:70.
Next, the composition according to Example 1 was obtained by removing toluene from this mixed solution using an evaporator.
Visual observation of the appearance of the obtained composition according to Example 1 revealed that it was transparent. As a result, it was confirmed that the zirconium oxide particles were suppressed from agglomeration and were relatively uniformly dispersed in the composition.

(Evaluation of stability of composition)
The viscosity of the composition of Example 1 was measured using a rheometer (trade name: Rheostress RS-6000, manufactured by HAAKE) at 25° C. and a shear rate of 1 (1/s).
As a result, the viscosity was 7.5 Pa·s.
This composition was stored at room temperature (25°C), and the viscosity was measured after one month. As a result, the viscosity of the composition was 23.5 Pa·s, which was at a level that could withstand practical use, although the viscosity increased. This also confirmed that the zirconium oxide particles were stably dispersed in the composition over a long period of time.

(4. Fabrication 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 according to Example 1, and surface-modified zirconium oxide particles were added to the composition. was adjusted to 2% by mass and mixed. A composition in which 0.38 parts by mass of phosphor particles (yttrium aluminum garnet: YAG) was mixed with 1 part by mass of this composition (total amount of surface-modified zirconium oxide particles and resin: phosphor particles = 100:38) was prepared. , filled into the LED lead frame to a thickness of 300 μm. Thereafter, it was kept at room temperature for 3 hours. Next, the composition was slowly heated and cured to form a sealing member, thereby producing a white LED package.

The brightness of the obtained white LED package was measured using a total luminous flux measurement system (manufactured by Otsuka Electronics Co., Ltd.) by applying a voltage of 3 V and a current of 150 mA to the LED package and performing photometry. As a result, the brightness of this white LED package was 75.1 lm.

[Example 2]
Example 2 was carried out in the same manner as in Example 1, except that zirconium oxide particles with an average primary particle size of 90 nm (manufactured by Sumitomo Osaka Cement Co., Ltd.) were used instead of zirconium oxide particles with an average primary particle size of 12 nm. Such a dispersion (third dispersion) was obtained. The content of zirconium oxide particles in the mixed solution obtained in the mixing step is 30% by mass, the content of methyltriethoxysilane is 63.5% by mass, and the total content of zirconium oxide particles and methyltriethoxysilane is 93%. It was .5% by mass.
Note that the solid content of the first dispersion liquid was measured (at 100° C. for 1 hour) and was found to be 70% by mass.

The particle size distribution of the zirconium oxide particles in the dispersion according to Example 2 was evaluated using a dispersion whose solid content was adjusted to 5% by mass with toluene in the same manner as in Example 1. As a result, D10 was 125 nm, D50 was 160 nm, and D90 was was 290 nm.
Furthermore, as in Example 1, FT-IR analysis was performed on the dispersion liquid according to Example 2, and the results showed that IA was 48.5, IB was 25.1, and IA/IB was 1.9. Ta.

The dispersion according to 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, and the toluene was removed to obtain the composition according to Example 2. Ta. Visual observation of the appearance of the obtained composition revealed that it was a transparent composition.

The viscosity of the composition was measured in the same manner as in Example 1, and the viscosity immediately after preparation was 6.5 Pa·s.
This composition was stored at room temperature (25°C), and the viscosity was measured after one month. As a result, the viscosity of the composition was 19.9 Pa·s, which was at a level sufficient for practical use, although the composition had thickened.

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 74.3 lm.

[Comparative example 1]
The mixing step was carried out in the same manner as in Example 1, except that in the mixing step, 20 parts by mass of the above hydrolyzed solution and 50 parts by mass of isopropyl alcohol were used instead of mixing 70 parts by mass of the above hydrolyzed solution. A dispersion process was performed to obtain a dispersion liquid (first dispersion liquid).
The solid content of the first dispersion was measured (at 100° C. for 1 hour) and was found to be 38% by mass.

(iv) First addition step Toluene was added to the obtained dispersion (first dispersion) so that the solid content was 20% by mass, and the mixture was heated at 60° C. for 2 hours. Next, toluene in the same amount as the volatilized amount was added to the dispersion, and the mixture was heated at 60° C. for 2 hours. Next, toluene in the same amount as the volatilized amount was added to the dispersion, and the mixture was heated at 60° C. for 1 hour. Next, the same amount of toluene as the volatilized amount was added to the dispersion and heated at 60° C. for 1 hour to promote surface modification and create a dispersion in which isopropyl alcohol was replaced with toluene (second dispersion). I got it.

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

The particle size distribution of the zirconium oxide particles in the dispersion according to Comparative Example 1 was evaluated using a dispersion whose solid content was adjusted to 5% by mass with toluene in the same manner as in Example 1. As a result, D10 was 91 nm, D50 was 112 nm, and D90 was was 136 nm.
Furthermore, when FT-IR analysis was performed on the dispersion 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 according to Comparative Example 1 whose 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 a composition capable of sealing an LED could not be obtained.

[Comparative example 2]
A dispersion according to Comparative Example 2 (third dispersion) was obtained in the same manner as in Example 1 except that methyltrimethoxysilane was used instead of methyltriethoxysilane in the hydrolysis step of Example 1. Ta.

The particle size distribution of the zirconium oxide particles in the dispersion according to Comparative Example 2 was evaluated using a dispersion whose solid content was adjusted to 5% by mass with toluene in the same manner as in Example 1. As a result, D10 was 104 nm, D50 was 122 nm, and D90 was was 143 nm.

When FT-IR analysis was performed on the dispersion according to Comparative Example 2 in which the solid content was adjusted to 30% by mass with toluene 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, and the toluene was removed to obtain a composition according to Comparative Example 2. . Visual observation of the appearance of the obtained composition revealed that it was a transparent composition.

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

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 dispersion manufacturing conditions, dispersion liquid, and evaluation of the composition in Example 1, Example 2, Comparative Example 1, and Comparative Example 2.

[Reference example]
A white LED package containing no surface-modified zirconium oxide particles was produced, and its brightness was measured. That is, in producing 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. A white LED package of a reference example was produced in the same manner as in Example 1 except for this.
The obtained white package was measured in the same manner as in Example 1, and the brightness of this white LED package was 72.5 lm.

As mentioned above, in Examples 1 and 2 in which zirconium oxide particles were dispersed in a highly concentrated silane compound, the zirconium oxide particles were suitably dispersed even when methylphenyl silicone and the dispersion were mixed. No turbidity or excessive increase in viscosity was observed. It was also confirmed that the brightness of the white LED package could be improved.
On the other hand, in Comparative Example 1, when methylphenyl silicone and the dispersion were mixed, the resulting composition gelled and was unsuitable as a composition for sealing a light emitting element.
In addition, by comparing Example 1 and Comparative Example 2, it was found that using methyltriethoxysilane in which the alkoxy group has 2 carbon atoms is better than using methyltrimethoxysilane in which the alkoxy group has 1 carbon number. It was confirmed that the increase in viscosity of the composition over time can be suppressed.

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

1A, 1B, 1C, 1D Light emitting device 2 Substrate 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 phosphor particles

Claims (7)

A dispersion containing metal oxide particles surface-modified with a surface-modifying material and a hydrophobic solvent, the dispersion comprising:
The surface modification material includes a silane compound and a silicone compound,
The transmission spectrum of the metal oxide particles obtained by drying the dispersion liquid by vacuum drying is measured using a Fourier transform infrared spectrophotometer in the wave number range of 800 cm ^-1 to 3800 cm ^-1 , and When the spectrum values are normalized so that the maximum value of the spectrum is 100 and the minimum value is 0, the following formula (1): IA/IB≦3.5 (1)
(In the formula, "IA" indicates the spectral value at 3500 cm ^-1 , and "IB" indicates the spectral value at 1100 cm ^-1 .)
satisfied,
the metal oxide particles are zirconium oxide particles,
The average dispersed particle diameter of the zirconium oxide particles is 10 nm or more and 300 nm or less,
the silane compound is methyltriethoxysilane ,
the silicone compound is a methoxy group-containing phenyl silicone resin,
The content of the silane compound in the dispersion is 50% by mass or more and 500% by mass or less based on the zirconium oxide particles,
A dispersion liquid in which the content of the silicone compound in the dispersion liquid is 50% by mass or more and 500% by mass or less based on the zirconium oxide particles . A mixture of the dispersion according to claim 1 and a resin component ,
A composition wherein the resin component is a methyl silicone resin . A sealing member which is a cured product of the composition according to claim 2. A light-emitting device comprising the sealing member according to claim 3 and a light-emitting element sealed by the sealing member. A lighting fixture comprising the light emitting device according to claim 4. A display device comprising the light emitting device according to claim 4. 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 liquid to obtain a first dispersion liquid in which the metal oxide particles are dispersed;
Step D of adding a hydrophobic solvent to the first dispersion to obtain a second dispersion;
a step E of adding a silicone compound to the second dispersion to obtain a third dispersion;
The 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% by mass or less. % by mass or more and 98% by mass or less,
In step D of adding the hydrophobic solvent, after heating the first dispersion, step d1 of adding the hydrophobic solvent at a rate that does not cause the metal oxide particles to aggregate, while heating the first dispersion. , step d2 of adding the hydrophobic solvent at a rate that does not cause the metal oxide particles to aggregate, or heating the first dispersion after adding the hydrophobic solvent at a rate that does not cause the metal oxide particles to aggregate. In step d3,
the metal oxide particles are zirconium oxide particles,
The average dispersed particle diameter of the zirconium oxide particles is 10 nm or more and 300 nm or less,
the silane compound is methyltriethoxysilane ,
the silicone compound is a methoxy group-containing phenyl silicone resin,
The content of the silane compound in the third dispersion is 50% by mass or more and 500% by mass or less based on the zirconium oxide particles,
A method for producing a dispersion liquid, wherein the content of the silicone compound in the third dispersion liquid is 50% by mass or more and 500% by mass or less based on the zirconium oxide particles .

Images