JP7243388B2 - Dispersion liquid, composition, sealing member, light-emitting device, lighting equipment, display device, and method for producing dispersion liquid - Google Patents

Description

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

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

As a sealing material for improving the extraction efficiency of light emitted from the LED chip, inorganic oxide particles having a dispersed particle diameter of 1 nm or more and 20 nm or less and a refractive index of 1.8 or more, and a silicone resin. (Patent Document 1).

In this composition, a dispersion containing inorganic oxide particles having a small dispersed particle size and a high refractive index is mixed with a silicone resin. Therefore, the inorganic oxide particles in the dispersion can improve the refractive index of the encapsulating material, and when the light emitted from the LED chip enters the encapsulating material, the interface between the LED chip and the encapsulating material has can suppress total reflection of light. As a result of these, the light extraction efficiency can be improved. Patent Document 1 also discloses modifying inorganic oxide particles with a surface modifying material.

JP 2007-299981 A

By the way, a composition for encapsulating a light-emitting element is required to have a relatively low viscosity in consideration of its handling, control of the shape of the composition at the time of encapsulation, and the like. On the other hand, there is a demand for further improvement in the brightness of light emitted from light-emitting devices. A composition using inorganic oxide particles that satisfies these two properties at the same time and a dispersion liquid that serves as a raw material for these properties have not been known in the past.

The present invention has been made in order to solve the above problems, and the dispersion has a relatively low viscosity when made into a composition and can improve the brightness of the light of a light emitting device, and the dispersion A composition produced using a liquid, a sealing member formed using the composition, a light-emitting device having the sealing member, a lighting fixture and a display device equipped with the light-emitting device, and a method for producing a dispersion liquid intended to provide

In order to solve the above-mentioned problems, according to one aspect of the present invention, inorganic oxide particles, a surface-modifying material attached to the inorganic oxide particles, a dispersion medium, and water are contained,
the dispersion medium comprises a hydrophobic solvent,
A dispersion liquid is provided in which the water content is 10 ppm or more and 300 ppm or less.

In order to solve the above problems, according to another aspect of the present invention, there is provided a composition for encapsulating a light-emitting element obtained by mixing a dispersion liquid and a resin component.
Moreover, in order to solve the above problems, according to another aspect of the present invention, there is provided a sealing member that is a cured product of the above composition.

Further, in order to solve the above problems, according to another aspect of the present invention, there is provided a light-emitting device including the sealing member and a light-emitting element sealed with the sealing member.
Moreover, in order to solve the above problems, according to another aspect of the present invention, there is provided a lighting fixture or a display device including the light emitting device.

In order to solve the above problems, according to another aspect of the present invention, a first step of mixing a surface-modifying material and water to obtain a mixed solution;
a second step of mixing the mixture, inorganic oxide particles, and a hydrophobic solvent to obtain a dispersion in which the inorganic oxide particles are dispersed;
a third step of removing at least a portion of the water from the dispersion;
and a fourth step of heating the dispersion.
In the third step, a hydrophobic solvent may be further added to the dispersion.

As described above, according to the present invention, a dispersion having a relatively low viscosity when formed into a composition and capable of improving the light brightness of a light-emitting device, a composition produced using the dispersion, and the composition It is possible to provide a sealing member formed using a material, a light-emitting device having this sealing member, a lighting fixture and a display device having this light-emitting device, and a method for producing a dispersion.

It is a schematic diagram showing an example of a light-emitting device according to an embodiment of the present invention.

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

<1. Dispersion>
The dispersion according to this embodiment contains inorganic oxide particles, a surface-modifying material attached to the inorganic oxide particles, a dispersion medium, and water.

In this embodiment, the dispersion medium contains a hydrophobic solvent and has a water content of 10 ppm or more and 300 ppm or less.

As described above, the dispersion liquid according to the present embodiment is mixed with the resin component to obtain a composition, and the composition is used to seal the light-emitting element, thereby improving the light brightness of the obtained light-emitting device. Furthermore, the compositions thus obtained have relatively low viscosities.

More specifically, the surface-modifying material adheres to the surfaces of the inorganic oxide particles, thereby contributing to improving the dispersion stability of the inorganic oxide particles. A small amount of water present in the dispersion promotes hydrolysis of the surface-modifying material, and as a result, promotes adhesion of the surface-modifying material to the surfaces of the inorganic oxide particles. On the other hand, since the resin component mixed when manufacturing the composition described below is generally hydrophobic, it is desirable that the dispersion contains a hydrophobic solvent as a dispersion medium. However, when the dispersion contains a hydrophobic solvent as a dispersion medium, water is difficult to mix with the hydrophobic solvent. Therefore, if water is excessively present, the viscosity of the composition increases when the dispersion and the resin component are mixed to obtain the composition. The inventors of the present invention conducted studies to solve such problems, and found that by controlling the water content in the dispersion to within a predetermined range, the hydrolysis of the surface-modifying material can be sufficiently promoted. It was found that an increase in the viscosity of the composition can be suppressed.
Each component contained in the dispersion will be described below.

(1.1 Inorganic oxide particles)
The inorganic oxide particles scatter light emitted from the light emitting element in the sealing member described later. Moreover, the inorganic oxide particles improve the refractive index of the sealing member depending on the type thereof. As a result, the inorganic oxide particles contribute to improving the brightness of the light of the light-emitting device.

The inorganic oxide particles contained in the dispersion according to this embodiment are not particularly limited. In the present embodiment, the inorganic oxide particles include, for example, zirconium oxide particles, titanium oxide particles, silica particles, zinc oxide particles, iron oxide particles, copper oxide particles, tin oxide particles, cerium oxide particles, tantalum oxide particles, oxide Niobium particles, tungsten oxide particles, europium oxide particles, yttrium oxide particles, molybdenum oxide particles, indium oxide particles, antimony oxide particles, germanium oxide particles, lead oxide particles, bismuth oxide particles and hafnium oxide particles and potassium titanate particles, titanium Barium oxide particles, strontium titanate particles, potassium niobate particles, lithium niobate particles, calcium tungstate particles, yttria-stabilized zirconia particles, alumina-stabilized zirconia particles, silica-stabilized zirconia particles, calcia-stabilized zirconia particles, magnesia-stabilized zirconia stabilized 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 Inorganic oxide particles containing at least one selected from the group consisting of zirconia particles, antimony-added tin oxide particles, and indium-added 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 selected from the group consisting of zirconium oxide particles, titanium oxide particles and silica particles. It is preferred that one species is included.

Moreover, the inorganic oxide particles preferably have a refractive index of 1.7 or more from the viewpoint of improving the refractive index of the sealing member. Examples of such inorganic oxide particles include inorganic oxide particles other than the silica particles described above.

The inorganic oxide particles are more preferably zirconium oxide particles and/or titanium oxide particles, and particularly preferably zirconium oxide particles.

The inorganic oxide particles may be dispersed as primary particles in the dispersion liquid, or may be dispersed as secondary particles in which the primary particles are aggregated. Inorganic oxide particles are usually dispersed as secondary particles.

The average dispersed particle diameter of the inorganic oxide particles in the dispersion is not particularly limited, but is, for example, 10 nm or more and 200 nm or less, preferably 20 nm or more and 150 nm or less, more preferably 30 nm or more and 150 nm or less. When the average dispersed particle diameter of the inorganic oxide particles is 10 nm or more, the light brightness of the light-emitting device manufactured using this dispersion liquid, which will be described later, is improved. In addition, when the average dispersed particle diameter of the inorganic oxide particles is 200 nm or less, it is possible to suppress a decrease in the light transmittance of the dispersion, the composition produced using the same, and the sealing member, which will be described later. . As a result, the brightness of light from the light emitting device is improved.

The average dispersed particle diameter of the inorganic oxide particles can be the particle diameter D50 of the inorganic oxide particles when the cumulative percentage of the scattering intensity distribution obtained by the dynamic light scattering method is 50%. It can be measured with a scattering type particle size distribution analyzer (eg, manufactured by HORIBA, model number: SZ-100SP). The measurement can be performed using a quartz cell with an optical path length of 10 mm×10 mm for a dispersion liquid adjusted to have a solid content of 5% by mass. As used herein, the term "solid content" refers to the residue left after removal of volatile components in the dispersion. For example, 1.2 g of the dispersion liquid is placed in a magnetic crucible and heated on a hot plate at 150 ° C. for 1 hour. be able to.

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

The average primary particle size of the inorganic oxide particles is, for example, 3 nm or more and 100 nm or less, preferably 4 nm or more and 80 nm or less, more preferably 10 nm or more and 60 nm or less. When the average primary particle size is within the above range, deterioration in transparency of the sealing member can be suppressed. As a result, the brightness of light from the light emitting device can be further improved.

The average primary particle size of the inorganic oxide particles can be measured, for example, by observation with a transmission electron microscope. First, a collodion film obtained by extracting inorganic oxide particles from a dispersion liquid is observed with a transmission electron microscope to obtain a transmission electron microscope image. Next, a predetermined number, for example 100, of the inorganic oxide particles in the transmission electron microscope image are selected. Then, the longest linear segment (maximum length) of each of these inorganic oxide particles is measured, and these measured values are arithmetically averaged.

Here, when the inorganic oxide particles are agglomerated, the agglomerated particle size of the agglomerates is not measured. A predetermined number of maximum major diameters of the particles (primary particles) of the inorganic oxide particles forming the aggregates are measured to determine the average primary particle diameter.

Moreover, the content of the inorganic oxide particles in the dispersion is not particularly limited as long as it can be mixed with the resin component described later. The content of the inorganic oxide particles in the dispersion liquid is, for example, 1% by mass or more and 70% by mass or less, preferably 5% by mass or more and 50% by mass or less, more preferably 10% by mass or more and 30% by mass or less.

As a result, it is possible to prevent the viscosity of the dispersion liquid from becoming excessively large, so that mixing with the resin component, which will be described later, is facilitated. In addition, it is possible to prevent the amount of the solvent (dispersion medium) from becoming excessive after mixing with the resin component, which facilitates the removal of the solvent.

A surface-modifying material described below is attached to the surfaces of the inorganic oxide particles described above. As a result, the inorganic oxide particles are stably dispersed in the dispersion liquid and the dispersion liquid produced using the dispersion liquid.

(1.2 Surface modification material)
The dispersion according to this embodiment contains a surface-modifying material. At least a portion of the surface-modifying material adheres to the surfaces of the inorganic oxide particles in the dispersion liquid to prevent aggregation of the inorganic oxide particles. Furthermore, it improves the compatibility with the resin component.

Here, the expression that the surface-modifying material "adheres" to the inorganic oxide particles means that the surface-modifying material contacts or bonds to the inorganic oxide particles through interaction or reaction therebetween. Contacting includes, for example, physical adsorption. Further, the bond includes an ionic bond, a hydrogen bond, a covalent bond, and the like.

Such a surface-modifying material is not particularly limited as long as it can adhere to the inorganic oxide particles and has good compatibility with the resin component as described later.
As such a surface-modifying material, a surface-modifying material having at least one functional group selected from the group of reactive functional groups such as alkenyl groups, H—Si groups, and alkoxy groups is preferably used. In particular, a surface modification material having an alkoxy group is preferably used in this embodiment because it can be hydrolyzed by reacting with water.

As the alkenyl group, for example, a linear or branched alkenyl group having 2 to 5 carbon atoms can be used, and specific examples include a vinyl group, a 2-propenyl group, a prop-2-en-1-yl group, and the like. be done.
Examples of the alkoxy group include linear or branched alkoxy groups having 1 to 5 carbon atoms, and specific examples include methoxy, ethoxy, n-propoxy, isopropoxy and butoxy groups.

Examples of surface-modifying materials having at least one functional group selected from the group consisting of alkenyl groups, H—Si groups, and alkoxy groups include the following silane compounds, silicone compounds, and carbon-carbon unsaturated bond-containing fatty acids. Among these, one of them can be used alone or two or more of them can be used in combination.

Examples of silane compounds include vinyltrimethoxysilane, isobutyltrimethoxysilane, phenyltrimethoxysilane, methacryloxypropyltrimethoxysilane, acryloxypropyltrimethoxysilane, dimethylchlorosilane, methyldichlorosilane, diethylchlorosilane, ethyldichlorosilane, Methylphenylchlorosilane, diphenylchlorosilane, phenyldichlorosilane, trimethoxysilane, dimethoxysilane, monomethoxysilane, triethoxysilane, diethoxymonomethylsilane, monoethoxydimethylsilane, methylphenyldimethoxysilane, diphenylmonomethoxysilane, methylphenyldiethoxy silane, diphenylmonoethoxysilane, and the like.

Examples of silicone compounds include methylhydrogensilicone, methylphenylhydrogensilicone, diphenylhydrogensilicone, alkoxy-terminated phenylsilicone, methylphenylsilicone, alkoxy-terminated methylphenylsilicone, alkoxy group-containing methylphenyl silicone, and alkoxy group-containing Examples include dimethyl silicone, alkoxy single-ended trimethyl single-ended (methyl group single-ended) dimethyl silicone, and alkoxy group-containing phenyl silicone.
The silicone compound may be an oligomer or a resin (polymer).
Examples of carbon-carbon unsaturated bond-containing fatty acids include methacrylic acid and acrylic acid.

Among these surface-modifying materials, vinyltrimethoxysilane, isobutyltrimethoxysilane, phenyltrimethoxysilane, and phenyltrimethoxysilane are preferred from the standpoint of suppressing aggregation of inorganic oxide particles in a dispersion and making it easier to obtain a highly transparent sealing member. The group of silane, alkoxy single-ended vinyl-single-ended methylphenyl silicone, alkoxy single-ended vinyl-single-ended phenyl silicone, alkoxy single-ended vinyl-single-single-ended dimethyl silicone, alkoxy one-single-ended trimethyl one-single-ended dimethyl silicone, methoxy group-containing phenyl silicone and methylphenyl silicone It is preferable to use one or two or more selected from.

The amount of the surface-modifying material relative to the inorganic oxide particles is not particularly limited, and is, for example, 10% by mass or more and 200% by mass or less, preferably 30% by mass or more and 150% by mass or less, and more preferably 50% by mass or more. It is 120% by mass or less. When the amount of the surface-modifying material is within the range described above, the dispersibility of the inorganic oxide particles can be sufficiently improved while reducing the amount of liberated surface-modifying material.

In the dispersion, the total content of the surface-modifying material and the inorganic oxide particles is preferably 2% by mass or more and 80% by mass or less, more preferably 10% by mass or more and 60% by mass or less, and still more preferably 20% by mass or more. It is 50% by mass or less. As a result, it is possible to prevent the viscosity of the dispersion from becoming excessively large, so that mixing with the resin component is facilitated. In addition, it is possible to prevent the amount of the solvent (dispersion medium) from becoming excessive after mixing with the resin component, which facilitates the removal of the solvent.

In addition, in the dispersion according to the present embodiment, the content of the surface-modifying material that is not attached to the inorganic oxide particles, i.e., the content of the surface-modifying material that is free in the dispersion (free surface-modifying material) is is preferably 50% by mass or less with respect to the total content of

The content of the free surface-modifying material may be, for example, 0% by weight or 0% by weight or more, 10% by weight or more, 20% by weight or more, or 30% by weight or more.

In this specification, the term "free surface-modifying material" means a surface-modifying material that is not attached to the inorganic oxide particles. The content of the free surface-modifying material is, for example, a value calculated by the following method, and is calculated based on the mass of the surface-modifying material that can be extracted from the dispersion with a good solvent for the surface-modifying material such as acetone.

The liquid in 5 g of the dispersion is removed by an evaporator to obtain a concentrate. Next, 2 g of acetone is added to this concentrate and mixed to prepare a mixed solution.
The extract separated from the mixture is collected by column chromatography using a column filled with 10 g of silica gel and 100 cc of developing solvent (hexane and acetone mixed at a volume ratio of 2:1). The liquid in this extract is removed by an evaporator, and the resulting residue is assumed to be a free surface-modifying material, and its mass is measured. The mass of the residue is divided by the total mass of the inorganic oxide particles and the surface-modifying material contained in 5 g of the dispersion liquid of the present embodiment, and the resulting percentage is defined as the content of the free surface-modifying material.

(1.3 Water)
Moreover, the dispersion according to the present embodiment contains water. And the content of water is 10 ppm or more and 300 ppm or less. As a result, the minute amount of water present in the dispersion accelerates the hydrolysis of the surface modifying material, and as a result, the adhesion of the surface modifying material to the surfaces of the inorganic oxide particles is promoted. And while the dispersibility of the inorganic oxide particles is maintained, free surface modification material is reduced. On the other hand, when the water content is reduced, the dispersion is easily mixed with the resin component described below, and the obtained composition maintains a low viscosity.

When the content of water contained in the dispersion exceeds 300 ppm, excessive water is contained in the dispersion, and as a result, when a composition is produced using the dispersion, water is mixed with the resin component in the composition. It becomes difficult to mix and as a result the viscosity of the resulting composition increases excessively. In addition, it becomes difficult to mix the dispersion medium with water, and the transparency of the dispersion is lowered. Furthermore, as a result of containing an excessive amount of water, the inorganic oxide particles in the dispersion liquid tend to agglomerate, and the dispersibility of the inorganic oxide particles rather decreases. On the other hand, when the content of water contained in the dispersion liquid is less than 10 ppm, hydrolysis of the surface-modifying material is insufficient, resulting in insufficient adhesion of the surface-modifying material to the surfaces of the inorganic oxide particles. , free surface modification material increases.

The content of water contained in the dispersion may be within the range described above, but is preferably 30 ppm or more and 200 ppm or less, more preferably 50 ppm or more and 100 ppm or less.

(1.4 dispersion medium)
Moreover, the dispersion liquid according to the present embodiment contains a dispersion medium for dispersing the inorganic oxide particles. And in this embodiment, the dispersion medium contains a hydrophobic solvent. The hydrophobic solvent has excellent dispersibility of the inorganic oxide particles and excellent compatibility with the resin component described later. Therefore, even when the dispersion liquid and the resin component are mixed to produce a composition, the dispersed state of the inorganic oxide particles is likely to be maintained.

Examples of hydrophobic solvents include aromatics, saturated hydrocarbons, unsaturated hydrocarbons, and the like. One of these solvents may be used, or two or more thereof may be used. Among those mentioned above, aromatics, particularly aromatic hydrocarbons, are preferred. Aromatics have excellent compatibility with silicone resins, which will be described later, and contribute to improving the viscosity characteristics of the resulting composition and improving the quality (transparency, shape, etc.) of the formed sealing member. On the other hand, aromatics, especially aromatic hydrocarbons, are hydrophobic solvents. Water is treated as an ingredient to be eliminated as much as possible, as it is expected to degrade the quality of the sealing member as a result. In the present embodiment, even when aromatics are used, the above-described trace amount of water is taken into the surface of the inorganic oxide particles via the alcohol solvent, and the dispersibility of the inorganic oxide particles in the dispersion liquid is improved. can be maintained.

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, and the like. These aromatic hydrocarbons may be used individually by 1 type, and may be used in combination of 2 or more type.

Among the above, from the viewpoint of the stability of the dispersion and ease of handling such as removal of the dispersion medium during the production of the composition described later, the dispersion medium may be toluene, o-, m- or p-xylene, One or more selected from the group consisting of benzene is particularly preferably used.

Further, the dispersion medium may contain a solvent other than the hydrophobic solvent described above. Examples of such solvents include alcohol-based solvents, ketone-based solvents, ether-based solvents, ester-based solvents, and the like, which are used in the manufacturing method described below. Even in such a case, the proportion of the hydrophobic solvent in the dispersion medium is, for example, 95% by mass or more, preferably 99% by mass or more.

The content of the dispersion medium in the dispersion liquid of the present embodiment is preferably 10% by mass or more and 98% by mass or less, more preferably 20% by mass or more and 80% by mass or less, and still more preferably 30% by mass or more and 70% by mass. % by mass or less.

In addition, the dispersion according to the present embodiment may contain components other than those described above as necessary, such as dispersants, dispersing aids, antioxidants, fluidity modifiers, thickeners, pH adjusters, preservatives, etc. General additives and the like may be included.

In this specification, the dispersion liquid according to the present embodiment is distinguished from the composition (sealing resin composition) according to the present embodiment, which contains a resin component and can be cured to form a sealing member. . That is, the dispersion liquid according to the present embodiment does not contain a resin component, which will be described later, to the extent that the sealing member can be formed by simply curing. More specifically, the mass ratio of the resin component and the inorganic oxide particles in the dispersion liquid according to the present embodiment may be in the range of 0:100 to 40:60 (resin component:inorganic oxide particles). Preferably, it is in the range of 0:100 to 20:80. The dispersion liquid according to the present embodiment is more preferably essentially free of the resin component described below, and particularly preferably completely free of the resin component described below.
The dispersion liquid according to this embodiment is mixed with a resin component as described later and used as a sealing member in a light emitting device for sealing a light emitting element.

<2. Dispersion Production Method>
Next, a method for producing a dispersion liquid according to this embodiment will be described. The method for producing a dispersion liquid according to the present embodiment includes a first step of mixing a surface modification material and water to obtain a mixed liquid, and mixing the mixed liquid, inorganic oxide particles, and a hydrophobic solvent. a second step of obtaining a dispersion in which the inorganic oxide particles are dispersed; a third step of removing at least part of the water from the dispersion; a fourth step of heating the dispersion; have

(2.1 First step)
In this step, the surface-modifying material and water are mixed to obtain a mixture. As a result, the surface modifying material is hydrolyzed by the water to which the surface modifying material is added, and a mixed liquid is obtained in which a part of the surface modifying material is hydrolyzed. By using a mixed solution in which at least a part of the surface modification material has been hydrolyzed in advance, the surface modification material easily adheres to the inorganic oxide particles in the dispersing step described later.

On the other hand, when this step is omitted and the inorganic oxide particles are dispersed by mixing the materials in the dispersion step, the hydrolysis reaction of the surface modifying material is less likely to occur, and the surface modifying material is sufficiently attached to the inorganic oxide particles. In order to disperse the particles, it is necessary to apply more energy for dispersion. For this reason, there is a problem that the surface-modifying material unintentionally deteriorates in the dispersing step to be described later, or does not sufficiently adhere to the inorganic oxide particles. In such a case, there is a problem that the dispersing liquid is colored by the liberated surface-modifying material, or the dispersibility of the inorganic oxide particles is not sufficient. As a result, the light extraction efficiency of the light-emitting device manufactured using the resulting dispersion is not sufficiently high.

As the surface-modifying material to be mixed in the liquid mixture, those listed as the constituent components of the dispersion liquid can be used.
The content of the surface-modifying material in the mixture is not particularly limited, but is, for example, 20% by mass or more and 70% by mass or less, preferably 30% by mass or more and 60% by mass or less, more preferably 40% by mass or more and 50% by mass. can be:

The content of water in the mixed liquid is not particularly limited, but is, for example, 1% by mass or more and 20% by mass or less, preferably 1% by mass or more and 15% by mass or less, more preferably 1% by mass or more and 10% by mass or less. can be. As a result, while the hydrolysis reaction of the surface-modifying material proceeds appropriately, the excessive amount of water increases the time required for water removal in the third step described later, and the water is uniform in the produced dispersion. It is possible to prevent mismixing and aggregation of inorganic oxide particles.

Moreover, the mixed liquid may contain an alcohol-based solvent. The alcohol-based solvent is miscible with water in any amount, and is also compatible with the hydrophobic solvent contained in the dispersion medium described above in a certain amount. Therefore, when the liquid mixture is mixed with the dispersion medium containing the inorganic oxide particles and the hydrophobic solvent, the hydrolyzed surface-modifying material contained in the liquid mixture easily adheres to the inorganic oxide particles. As a result, the dispersibility of the inorganic oxide particles is improved and the amount of free surface modification material is reduced in the dispersion.

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

In addition, from the viewpoint of excellent affinity with both water and hydrophobic solvents and promotion of their mixing, the number of carbon atoms in the alcohol compound constituting the alcohol-based solvent is preferably 1 or more and 3 or less, more preferably 1 or more and 2 or less. It is below.
Among those mentioned above, methanol and ethanol, particularly methanol, can be preferably used because they can sufficiently exhibit the effects of the alcohol solvent.

The content of the alcohol solvent in the mixed liquid is not particularly limited, but is, for example, 20% by mass or more and 70% by mass or less, preferably 30% by mass or more and 60% by mass or less, more preferably 40% by mass or more and 50% by mass or less. can be As a result, the content of the surface-modifying material in the mixed liquid can be sufficiently increased, and a sufficient amount of water can be included in the mixed liquid. As a result, the hydrolysis reaction of the surface-modifying material can be efficiently performed. can proceed.

Moreover, a catalyst may be added to the mixed liquid. Acids or bases, for example, can be used as catalysts.
The acid catalyzes hydrolysis of the surface modification material in the mixture. On the other hand, the base catalyzes the condensation reaction between the hydrolyzed surface modifier and the functional groups on the surface of the inorganic oxide particles, such as hydroxyl groups and silanol groups. This makes it easier for the surface-modifying material to adhere to the inorganic oxide particles in the second step, which will be described later, and improves the dispersion stability of the inorganic oxide particles. In addition, since the surface-modifying material easily adheres to the inorganic oxide particles, the amount of free surface-modifying material is reduced, and the light transmittance of the dispersion, the composition produced using the same, and the sealing member is improved. do. Here, the above-mentioned "acid" refers to an acid based on the so-called Bronsted-Lowry definition, and refers to a substance that gives protons in the hydrolysis reaction of the surface-modifying material. The above-mentioned "base" refers to a base based on the so-called Bronsted-Lowry definition, and here refers to a substance that accepts protons in the hydrolysis reaction and subsequent condensation reaction of the surface-modifying material.

The acid that can be used in the dispersion liquid according to the present embodiment is not particularly limited as long as it can supply protons in the hydrolysis reaction of the surface-modifying material. Examples include hydrochloric acid, hydrobromic acid, hydroiodic acid, Inorganic acids such as sulfuric acid, nitric acid, boric acid, phosphoric acid, etc., and organic acids such as acetic acid, citric acid, formic acid, etc. can be mentioned, and one of these can be used alone or in combination of two or more.

The base that can be used in the production method according to the present embodiment is not particularly limited as long as it can accept protons in the hydrolysis reaction of the surface-modifying material and the subsequent condensation reaction. Examples include sodium hydroxide and potassium hydroxide. , barium hydroxide, calcium hydroxide, ammonia, amines, and the like, and one of these can be used alone or two or more of them can be used in combination.

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

The content of the catalyst in the mixture is not particularly limited, and can be, for example, 10 ppm or more and 1000 ppm or less, preferably 20 ppm or more and 800 ppm or less, more preferably 30 ppm or more and 600 ppm or less. This makes it possible to sufficiently promote the hydrolysis reaction of the surface-modifying material while suppressing unwanted side reactions of the surface-modifying material.

Moreover, after the mixed solution is prepared, it may be held at a constant temperature for a predetermined time. This can further promote hydrolysis of the surface modification material.
In this treatment, the temperature of the mixed solution is not particularly limited and can be appropriately changed depending on the type of the surface-modifying material.

The holding time is not particularly limited, but is, for example, 10 minutes or more and 180 minutes or less, preferably 30 minutes or more and 120 minutes or less.
It should be noted that the mixed liquid may be appropriately stirred during the holding of the mixed liquid.

(2.2 Second step)
Next, the liquid mixture, the inorganic oxide particles, and the hydrophobic solvent are mixed to obtain a dispersion liquid in which the inorganic oxide particles are dispersed. As described above, the surface modification material is hydrolyzed in advance in the hydrolysis step. Therefore, in this step, the surface-modifying material is in a state where it easily adheres to the inorganic oxide particles, and the energy input for dispersing the inorganic oxide particles in this step can be reduced. As a result, unintentional deterioration of the surface-modifying material during dispersion is suppressed, the amount of free surface-modifying material is reduced, and the light transmittance of the dispersion is improved.

Further, in the present embodiment, the mixed liquid may contain an alcohol-based solvent in advance. In this case, the alcohol-based solvent can promote mixing of the hydrophobic solvent and the hydrolyzed surface-modifying material. This makes it easier for the surface-modifying material to adhere to the inorganic oxide particles.

In the liquid (dispersion liquid) obtained by mixing the mixed liquid, the inorganic oxide particles, and the hydrophobic solvent, the content of the alcohol solvent is not particularly limited, but is, for example, 1.0% by mass or more and 20% by mass or less. can be As a result, mixing of the hydrophobic solvent and the hydrolyzed surface modifying material by the alcoholic solvent can be further promoted. Furthermore, since the hydrophobic solvent can be sufficiently contained in the dispersion, the dispersibility of the inorganic oxide particles in the dispersion is improved. The content of the alcohol solvent is preferably 1.0% by mass or more and 15% by mass or less, more preferably 1.0% by mass or more and 10% by mass or less.

In the dispersion, the content of the alcohol solvent relative to the content of the hydrophobic solvent is not particularly limited, but is, for example, 1% by mass or more and 20% by mass or less, preferably 2% by mass or more and 15% by mass or less. can be done. As a result, the dispersibility improvement effect of the inorganic oxide particles by the hydrophobic solvent can be sufficiently obtained, and the mixing of the hydrophobic solvent and the hydrolyzed surface-modifying material by the alcohol-based solvent can be further promoted.

The dispersion can be produced, for example, by mixing each component of the dispersion and then dispersing the mixture with a known dispersing machine while controlling the power of the dispersing machine. Here, the dispersion liquid according to the present embodiment is prepared by using a known dispersing machine, so that the particle size (dispersion particle size) of the inorganic oxide particles in the dispersion liquid becomes substantially uniform, and excessive energy is not applied. Instead, it is preferable to apply and disperse the minimum necessary energy.

As known dispersers, for example, bead mills, ball mills, homogenizers, dispersers, stirrers and the like are preferably used.

(2.3 Third step)
In this step, at least part of the water is removed from the dispersion. As a result, in the first step and the second step described above, a sufficient amount of water is used for hydrolysis of the surface-modifying material, while the water content in the resulting dispersion is It is possible to reduce the viscosity of the composition to such an extent that an increase in viscosity can be suppressed. Furthermore, by removing alcohol and the like generated by hydrolysis together with water, the heating temperature can be set to the boiling point of the dispersion medium in the fourth step described later, and the reaction of the surface-modifying material can proceed more reliably. can be made

On the other hand, when this step is omitted, considering the viscosity of the composition, it may not be possible to use a sufficient amount of water necessary for hydrolyzing the surface-modifying material. Alternatively, when a sufficient amount of water required for hydrolysis of the surface-modifying material is used in the first step and the second step, a large amount of water is present in the finally obtained dispersion, resulting in Viscosity increases. Furthermore, as a result of not being able to raise the heating temperature in the fourth step described later, the surface-modifying material does not sufficiently adhere to the inorganic oxide particles, and the amount of free surface-modifying material tends to increase. Also, the dispersibility of the inorganic oxide particles is not sufficiently improved.

Removal of water from the dispersion can be performed by appropriately combining, for example, pressure reduction treatment, heat treatment, and the like. Specifically, water can be easily removed by heat treatment to remove the separated water while refluxing the solvent of the dispersion. For example, the reflux can be performed by using a Dean-Stark apparatus or the like.

Therefore, when heat treatment is performed, the heating temperature can be the reflux temperature of the dispersion medium. In addition, when the dispersion medium contains a component capable of azeotroping with water, the reflux temperature may change as the component capable of azeotroping with water is removed. For example, when the dispersion medium contains toluene, the reflux temperature rises to about 110° C., the reflux temperature of toluene, along with the removal of components capable of azeotroping with water.

The degree of water removal from the dispersion is not particularly limited, but it is preferable to remove water until the water content in the dispersion satisfies the range described above.

Further, when the dispersion contains an alcoholic solvent, the alcoholic solvent is removed from the dispersion in the same manner as water in this step. Furthermore, when acid is included in the dispersion, the acid can be removed together with water.

Moreover, the time for removing the water in this step is not particularly limited, and is selected as necessary until the amount of water is reduced to the desired amount.

In addition, in this step, a hydrophobic solvent may be further added to the dispersion. In this step, the hydrophobic solvent can also be removed together with the water, for example, during reflux. In this case, the dispersibility of the inorganic oxide particles may decrease as the amount of the hydrophobic solvent decreases. Therefore, by appropriately adding a hydrophobic solvent to the dispersion, such problems can be prevented.

Moreover, the timing of addition of the hydrophobic solvent is not particularly limited, and it may be added continuously throughout the process, or may be added intermittently. Moreover, the amount to be added is also not particularly limited, and is appropriately selected so that the desired amount of the hydrophobic solvent is contained in the finally obtained dispersion.

(2.4 Fourth step)
The dispersion is then heated. This promotes the reaction of the surface modification material, and more surface modification material adheres to the inorganic oxide particles. As a result, the amount of free surface-modifying material present in the dispersion is reduced, and the dispersion stability of the inorganic oxide particles is further improved. In this step, a certain amount of water is removed from the dispersion in the third step. Therefore, the heating temperature, for example, the reflux temperature, can be the boiling point of the dispersion medium, and the reaction of the surface modification material can proceed more reliably.

In this treatment, the temperature of the dispersion liquid is not particularly limited and can be appropriately changed depending on the type of the surface-modifying material. Alternatively, it may be the reflux temperature of the dispersion.

The retention time is not particularly limited, but is, for example, 30 minutes or more and 720 minutes or less, preferably 90 minutes or more and 180 minutes or less.
In addition, in holding the above dispersion, the mixed liquid may be stirred as appropriate.

By the above method, the dispersion liquid according to the present embodiment can be obtained. By hydrolyzing the surface-modifying material in advance in the dispersion obtained as described above, the amount of energy input during dispersion is small, so that undesired deterioration of the surface-modifying material is suppressed. Moreover, the surface-modifying material adheres sufficiently to the inorganic oxide particles through the first step, and the dispersibility of the inorganic oxide particles is improved. Furthermore, the amount of free surface modification material is also reduced. As a result, when a composition containing a resin component is produced using this and a light-emitting element is sealed using the composition, the brightness of the light of the light-emitting device is improved.
Furthermore, since the content of water in the resulting dispersion can be relatively low, it is possible to reduce the viscosity of the composition when it is mixed with the resin component to produce the composition.

<3. Composition>
Next, the composition according to this embodiment will be described. The composition according to this embodiment is obtained by mixing the dispersion liquid according to this embodiment and the resin component. Therefore, the composition according to the present embodiment contains the above-described inorganic oxide particles, a surface-modifying material at least partially attached to the inorganic oxide particles, and a resin component, that is, a resin and/or a precursor thereof. include.
In addition, the composition according to the present embodiment is cured as described later and used as a sealing member for a light-emitting element. That is, the composition according to this embodiment is a sealing resin composition.

The content of the inorganic oxide particles in the composition of the present embodiment is 0.005% by mass or more and 50% by mass or less from the viewpoint of obtaining high light scattering efficiency while increasing the transparency of the sealing member. more preferably 0.05% by mass or more and 30% by mass or less, and even more preferably 0.5% by mass or more and 20% by mass or less.

Also, the content of the surface modifying material and the content of the free surface modifying material can be the same as the content in the dispersion according to the present embodiment.

The resin component is the main component in the composition according to this embodiment. When the composition according to the present 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. to prevent In addition, in the present 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, and for example, resins such as silicone resins and epoxy resins can be used. In particular, silicone resins are preferred.

The silicone resin is not particularly limited as long as it is used as a sealing material. For example, dimethylsilicone resin, methylphenylsilicone resin, phenylsilicone resin, organically modified silicone resin, and the like can be used.

In particular, when a surface modifying material having at least one functional group selected from the group consisting of an alkenyl group, an H—Si group, and an alkoxy group is used as the surface modifying material, H—Si It is preferred to use a silicone resin having at least one functional group selected from the group consisting of a group, an alkenyl group and an alkoxy group. The reason is explained below.

Alkenyl groups of the surface modification material are crosslinked by reacting with H—Si groups in the silicone resin. The H—Si groups of the surface modification material are crosslinked by reacting with the alkenyl groups in the silicone resin. The alkoxy group of the surface modification material is condensed through hydrolysis with the alkoxy group in the silicone resin. Such bonding integrates the silicone resin and the surface-modifying material, thereby improving the strength and denseness of the resulting sealing member.

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 curing, that is, a precursor in the composition. Accordingly, the resin component present in the composition may be monomeric, oligomeric, or polymeric.

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, 0.1 Pa s or more and 100 Pa s or less, preferably 1 Pa s or more and 50 Pa s or less, more preferably 2 Pa s. s or more and 10 Pa·s or less.

Moreover, the content of the resin component in the composition according to the present embodiment can be the balance of other components, and is, for example, 80% by mass or more and 99.9% by mass or less.

The composition according to the present embodiment may contain the dispersion medium derived from the dispersion liquid according to the present embodiment, or may be removed. That is, the dispersion medium derived from the dispersion may be completely removed, and may remain in the composition in an amount of 1% by mass or more and 10% by mass or less relative to the mass of the composition, or 2% by mass or more and 5% by mass. The amount below may remain.
Moreover, the composition according to the present embodiment may contain water derived from the dispersion liquid according to the present embodiment, or may be removed. That is, the water derived from the dispersion liquid may be completely removed, and the water derived from the dispersion liquid and the resin component may remain in the composition at about 0.1 ppm or more and 200 ppm or less with respect to the mass of the composition. , 1 ppm or more and 100 ppm or less may remain.

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

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

In addition, the composition of the present embodiment contains commonly used additives such as preservatives, polymerization initiators, polymerization inhibitors, curing catalysts, light diffusing agents, etc., to the extent that the objects of the present invention are not impaired. may have been Silica particles having an average particle size of 1 to 30 μm are preferably used as the light diffusing agent.

In addition, the viscosity of the composition according to the present embodiment at 25° C. measured according to JIS Z 8803:2011 is not particularly limited, but is, for example, 100 Pa s or less, preferably 5 Pa s or more and 100 Pa s or less, More preferably, it can be 10 Pa·s or more and 70 Pa·s or less. This facilitates industrial handling of the composition. Furthermore, the inorganic oxide particles can be uniformly dispersed during mixing with the resin.

Although the viscosity of the composition as described above depends on the viscosity of the resin component, it can be achieved relatively easily by adjusting the water content in the dispersion to within the range described above.

The composition according to this embodiment can be produced, for example, by mixing the dispersion liquid according to this embodiment and a resin component. After mixing, if necessary, the dispersion medium contained in the dispersion may be removed by an evaporator or the like.

According to the embodiment described above, the composition according to the embodiment is obtained by mixing the dispersion liquid according to the embodiment and the resin component. Since the dispersion contains a hydrophobic solvent as a dispersion medium, the dispersion can be well mixed with the resin component, and the inorganic oxide particles are sufficiently dispersed and mixed in the composition without excessive agglomeration. In addition, the dispersion is prevented from being colored due to unintended deterioration of the surface-modifying material. Therefore, the composition according to the present embodiment suppresses a decrease in light transmittance due to the inorganic oxide particles when used as a sealing member, and the effect of improving the refractive index due to the inorganic oxide particles and the light emitted from the light emitting element. It is possible to fully exhibit the light scattering effect that is required. As a result, the brightness of light of a light-emitting device having a light-emitting element sealed with the composition according to this embodiment is improved.
Furthermore, since the dispersion has a relatively small amount of water, the increase in viscosity of the composition is reduced, and industrial handling is easy.

<4. Sealing member>
The sealing member according to this embodiment is a cured product of the composition according to this embodiment. The sealing member according to the present embodiment is usually used as a sealing member arranged on the light emitting element or a part thereof.

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

The thickness and shape of the sealing member according to the present embodiment can be appropriately adjusted according to desired uses and characteristics, and are not particularly limited.

The average dispersed particle size of the inorganic oxide particles in the sealing member is preferably 10 nm or more and 500 nm or less, more preferably 20 nm or more and 300 nm or less, and still more preferably 40 nm or more and 200 nm or less.

When the average dispersed particle diameter is 10 nm or more, a sufficient light scattering effect can be obtained, and the light brightness of the light emitting device can be further improved. On the other hand, when the average dispersed particle diameter is 500 nm or less, the transmittance of the sealing member can be moderately increased, and the brightness of the light of the light emitting device can be further improved.

The average dispersed particle diameter of the inorganic oxide particles in the sealing member is the average particle diameter (median diameter, D50) based on the number distribution, measured by transmission electron microscope observation (TEM) of the sealing member. . Further, the average dispersed particle size of the inorganic oxide particles in the sealing member in the present embodiment is a value measured and calculated based on the dispersed particle size of the inorganic oxide particles in the sealing member. The average dispersed particle size is measured and calculated based on the diameter of the dispersed inorganic oxide particles, regardless of whether the inorganic oxide particles are dispersed as primary particles or secondary particles. . Further, in the present embodiment, the D50 of the inorganic oxide particles in the sealing member may be measured as the D50 of the inorganic oxide particles to which the surface modification material is adhered. In the sealing member, inorganic oxide particles to which the surface modifying material is attached and inorganic oxide particles to which the surface modifying material is not attached may exist. D50 is measured as a value in these mixed conditions.

Since the sealing member according to the present embodiment is a cured product of the composition according to the present embodiment, it has excellent light transmittance, the effect of improving the refractive index due to the inorganic oxide particles, and the light emitted from the light emitting element. The scattering effect of is fully exhibited. Therefore, the light emitting device using the sealing member according to this embodiment has improved brightness of emitted light.

<5. Light-emitting device>
Next, the light emitting device according to this embodiment will be described. A light-emitting device according to this embodiment includes the above-described sealing member and a light-emitting element sealed with the sealing member.
Examples of light-emitting elements include light-emitting diodes (LEDs) and organic light-emitting diodes (OLEDs). In particular, the sealing member according to this embodiment is suitable for sealing light emitting diodes.

The light-emitting device according to the present embodiment will be described below by taking 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. FIG. 1 is a schematic diagram (cross-sectional view) showing an example of a light-emitting device according to an embodiment of the present invention. Note that the size of each member in the drawings is appropriately emphasized for ease of explanation, and does not represent actual dimensions or ratios between members.

A light emitting device (LED package) 1 shown in FIG. and a sealing member 4 for sealing.

The sealing member 4 is configured by the sealing member according to the present embodiment described above. Therefore, the sealing member 4 has a high light transmittance due to its suppressed coloring, and fully exhibits the effect of improving the refractive index due to the inorganic oxide particles and the effect of scattering the light emitted from the light emitting element. It is Therefore, the brightness of the light emitted from the light emitting device 1 is improved. Further, phosphor particles 5 are dispersed in the sealing member 4 . The phosphor particles 5 convert the wavelength of at least part of the light emitted from the light emitting element 3 .

It should be noted that the light-emitting device according to the present invention is not limited to the illustrated embodiment. For example, the light emitting device according to the present invention may not contain phosphor particles in the sealing member. Moreover, the sealing member according to the present embodiment can exist at any position in the sealing member. Moreover, in one embodiment of the present invention, the sealing member is composed of a plurality of layers, and the composition of these layers may be the same or different. In this case, any one or more layers are composed of the sealing member according to the present embodiment.

As described above, the light emitting device according to the present embodiment is excellent in light extraction efficiency because the light emitting element is sealed with the sealing member of the present embodiment.

In addition, in the light-emitting device according to this embodiment, the light-emitting element is sealed with the composition according to this embodiment as described above. Therefore, in one aspect, the present invention also relates to a method for manufacturing a light-emitting device, which includes sealing a light-emitting element using the composition according to this embodiment. In the same aspect, the production method may include a step of mixing the dispersion liquid according to the present embodiment and a resin component to produce the composition. Furthermore, at least part of the dispersion medium may be removed in the process of producing the composition.

The light-emitting device according to this embodiment as described above can be used, for example, in lighting fixtures and display devices. Accordingly, in one aspect, the present invention relates to a lighting fixture or display device comprising the light emitting device according to the present embodiments.

Examples of lighting fixtures include general lighting devices such as indoor lights and outdoor lights, lighting for switch units of electronic devices such as mobile phones and OA equipment, and the like.
Since the lighting fixture 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 greater than in the conventional case, 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 their peripherals.
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 greater than that of the conventional display device. It can be performed.

The present invention will be described in more detail below with reference to examples. It should be noted that the embodiments described below are merely examples of the present invention, and do not limit the present invention.

[Example 1]
(Preparation of dispersion liquid)
(1) First Step 5 parts by mass of a methoxy group-containing phenyl silicone resin (manufactured by Shin-Etsu Chemical Co., Ltd., product name KR217) as a surface modification material and 5 parts by mass of methanol were mixed. Then, 0.4 parts by mass of water and 0.2 parts by mass of hydrochloric acid (1N) were added and mixed. This mixture was then stirred at 60° C. for 30 minutes to hydrolyze the methoxy group-containing phenylsilicone resin.

(2) Second step 10 parts by mass of zirconium oxide particles (manufactured by Sumitomo Osaka Cement Co., Ltd.) having an average primary particle diameter of 12 nm, 82 parts by mass of toluene, and 10.6 parts by mass of the above mixture are mixed, and a second mixing is performed. A liquid was obtained, and the beads were removed after dispersing this second liquid mixture in a bead mill for 6 hours. The content of methanol in the dispersion liquid in this step was 4.9% by mass.

(3) Third Step The dispersion after removal of the beads was refluxed in an oil bath at 130° C. for 30 minutes to remove water from the dispersion. Thereafter, after adding toluene in an amount equivalent to the volatilized amount to the dispersion, the dispersion was refluxed in an oil bath at 130° C. for 30 minutes to further remove water.

(4) Fourth step The dispersion after removing water is refluxed in an oil bath at 130°C for 6 hours to obtain the dispersion according to Example 1 in which the zirconium oxide particles are surface-modified with the methoxy group-containing phenyl silicone resin. rice field.

(Evaluation of dispersion liquid)
1.2 g of the resulting dispersion was placed in a magnetic crucible and heated on a hot plate at 150° C. for 1 hour. As a result, the solid content was 33.1% by mass. The solid content is the percentage obtained by dividing the mass of the component remaining without volatilization by the mass of the dispersion liquid (1.2 g). In addition, the obtained solid content mainly contains zirconium oxide particles and surface modification material. Therefore, the obtained solid content is considered to correspond to the total content of the zirconium oxide particles and the surface-modifying material (surface-modified zirconium oxide particles) in the dispersion.

The water content of the resulting dispersion was measured with a Karl Fischer moisture meter (model number: AQ-2000 (coulometric method, manufactured by Hiranuma Sangyo Co., Ltd.)) and found to be 52 ppm.
In addition, the dispersion was burned in a combustion device, the generated combustion decomposition gas was collected in the absorbent, and the content of hydrochloric acid contained in the dispersion was measured by ion chromatography. there were.
Furthermore, as a result of detecting methanol in the dispersion by gas chromatography-mass spectrometry, it was confirmed that the dispersion did not contain methanol.

Furthermore, using a dispersion diluted with toluene so that the solid content is 5% by mass, the integrated transmittance at a wavelength of 460 nm is measured using a quartz cell with an optical path length of 10 mm with a spectrophotometer (manufactured by JASCO Corporation, model number: V -770) was 39%.
In addition, the average dispersed particle diameter D50 of the zirconium oxide particles contained in the dispersion diluted with toluene so that the solid content is 5% by mass was measured using a particle size distribution diameter (manufactured by HORIBA, model number: SZ-100SP). , 32 nm.

(Evaluation of content of free surface-modifying material)
5 g of the obtained dispersion liquid (total content of zirconium oxide particles and surface modifying material: 1.6 g) was removed by an evaporator.
2 g of acetone was added to this concentrate and mixed to prepare a mixture.
The extract separated from the mixture was collected by column chromatography using a column filled with 10 g of silica gel and 100 cc of developing solvent (hexane and acetone mixed at a volume ratio of 2:1). The collected liquid was removed by an evaporator, and the resulting residue was used as a free surface-modifying material, and its mass was measured. The percentage of the value obtained by dividing the mass of this residue by the total mass (1.6 g) of the zirconium oxide particles and the surface-modifying material contained in 5 g of the dispersion was calculated.
As a result, the content of the free surface-modifying material was 20% by mass.

(Production of composition)
10 parts by mass of the resulting dispersion, methylphenyl silicone resin ("KER-6150 (A/B) (A liquid: B liquid = 1: 1)" refractive index 1.41) manufactured by Shin-Etsu Chemical Co., Ltd.) 7.6 mass (3.8 parts by mass of A liquid and 3.8 parts by mass of B liquid) were mixed. That is, they were mixed so that the surface-modified zirconium oxide particles accounted for 30% by mass of the total content of the methylphenyl silicone resin and the surface-modified zirconium oxide particles. Then, by removing toluene from this mixed solution with an evaporator, a composition according to Example 1 containing the zirconium oxide particles to which the surface modifying material was attached, the methylphenylsilicone resin, and the reaction catalyst was obtained.

(Evaluation of composition)
The obtained composition according to Example 1 was sandwiched between thin-layer quartz cells to have a thickness (optical path length) of 1 mm, and the integrated transmittance at a wavelength of 460 nm was measured with a spectrophotometer (manufactured by JASCO Corporation, model number: V- 770) was 60%.
Further, the viscosity of the obtained composition according to Example 1 was measured using a rheometer (Rheostress RS-6000, manufactured by HAAKE) at a shear rate of 1 (1/s), and was 31 Pa s. Met. In addition, the measurement of the viscosity was performed at the temperature of 25 degreeC based on JISZ8803.

(Production of LED package)
To 1 part by mass of the obtained composition, 14 parts by mass of methylphenyl silicone resin (KER-6150 (A/B) manufactured by Shin-Etsu Chemical Co., Ltd.) was added, and the composition contained 2% by mass of surface-modified zirconium oxide particles. A composition (total amount of surface-modified zirconium oxide particles and resin: Phosphor particles=100:38) is filled into the LED lead frame to a thickness of 300 μm.Then, it is kept at room temperature for 3 hours.Then, the composition is slowly heat-cured to form a sealing member. A white LED package according to Example 1 was produced.

Luminous efficiency of the resulting white LED package was measured by applying a voltage of 3 V and a current of 150 mA to the LED package and performing photometry using a total luminous flux measurement system (manufactured by Otsuka Electronics Co., Ltd.). As a result, the brightness of the white LED package according to Example 1 was 78.3 lm.

[Comparative Example 1]
(Preparation of dispersion liquid)
Zirconium oxide particles with an average primary particle size of 12 nm (manufactured by Sumitomo Osaka Cement Co., Ltd.) 10 parts by weight, toluene 82 parts by weight, 5 parts by weight of methoxy group-containing phenyl silicone resin (Shin-Etsu Kogyo Chemical Co., Ltd. KR217) as a surface modification material, water 0.05 parts by mass were mixed and dispersed in a bead mill for 6 hours. Next, the dispersion after removal of the beads was refluxed in an oil bath at 130° C. for 6 hours to obtain a dispersion according to Comparative Example 1 in which the zirconium oxide particles were surface-modified with the methoxy group-containing phenylsilicone resin.

(Evaluation of dispersion liquid)
Regarding the obtained dispersion liquid according to Comparative Example 1, the contents of water, hydrochloric acid, free surface-modifying material, the average dispersed particle diameter D50 of zirconium oxide particles, and the integrated transmittance at a wavelength of 460 nm were measured in the same manner as in Example 1. bottom. Table 1 shows the results.

(Preparation and evaluation of composition)
A composition was prepared in the same manner as in Example 1, and a composition according to Comparative Example 1 was obtained. Regarding the obtained composition, in the same manner as in Example 1, the integrated transmittance and viscosity at a wavelength of 460 nm were measured. Table 1 shows the results.

(Production and evaluation of LED packages)
A white LED package according to Comparative Example 1 was produced in the same manner as in Example 1 using the obtained composition. Luminous efficiency was measured in the same manner as in Example 1 for the resulting white LED package. Table 1 shows the results.

[Comparative Examples 2 and 3]
(Preparation of dispersion liquid)
Dispersions according to Comparative Examples 2 and 3 were prepared in the same manner as in Example 1 except that the amount of methanol mixed in the first step was changed as shown in Table 1 and the third step was omitted. The amount of the mixed liquid added in the second step was adjusted so that the amount of the methoxy group-containing phenylsilicone resin was the same as in Example 1. Table 1 shows the content of methanol in the dispersion in the second step.

[Comparative Example 4]
A dispersion liquid according to Comparative Example 4 was obtained in the same manner as in Example 1, except that the third step was not performed. That is, after the second step of Example 1, the dispersion after bead removal was refluxed in an oil bath at 130° C. for 6 hours to obtain a dispersion according to Comparative Example 4.

(Evaluation of dispersion liquid)
Regarding the obtained dispersions according to Comparative Examples 2 to 4, the contents of water, hydrochloric acid, free surface-modifying material, the average dispersed particle diameter D50 of the zirconium oxide particles, and the integrated transmittance at a wavelength of 460 nm were measured in the same manner as in Example 1. was measured. Table 1 shows the results.

(Preparation and evaluation of composition)
Compositions were produced in the same manner as in Example 1, and compositions according to Comparative Examples 2 to 4 were obtained. Regarding the obtained composition, in the same manner as in Example 1, the integrated transmittance and viscosity at a wavelength of 460 nm were measured. Table 1 shows the results.

(Production and evaluation of LED packages)
White LED packages according to Comparative Examples 2 to 4 were produced in the same manner as in Example 1 using the obtained compositions. The brightness of the resulting white LED package was measured in the same manner as in Example 1. Table 1 shows the results.

From the results of Example 1 and Comparative Examples 1 to 4, in Example 1 according to the present invention, the obtained composition has excellent integrated transmittance, and as a result, the light of the obtained light emitting device (LED package) was shown to be able to improve the brightness of Furthermore, in Example 1 according to the present invention, the resulting composition had a relatively low viscosity and was easy to handle.

As described above, the effect of improving the brightness of the light of the light-emitting device (LED package) and reducing the viscosity of the composition in Example 1 is attributed to performing the first step and the third step. it was thought.

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

REFERENCE SIGNS LIST 1 light emitting device 2 substrate 21 recess 3 light emitting element 4 sealing member 5 phosphor particles

Claims (7)

Containing inorganic oxide particles, a surface-modifying material at least partially attached to the inorganic oxide particles, a dispersion medium, and water,
the dispersion medium comprises a hydrophobic solvent,
The water content is 10 ppm or more and 300 ppm or less,
The content of the surface-modifying material not attached to the inorganic oxide particles among the surface-modifying materials is 50% by mass or less with respect to the total content of the inorganic oxide particles and the surface -modifying material. liquid. A composition for encapsulating a light-emitting element, obtained by mixing the dispersion according to claim 1 and a resin component. A sealing member, which is a cured product of the composition according to claim 2 . A light-emitting device comprising: the sealing member according to claim 3; and a light-emitting element sealed with the sealing member. A lighting fixture or display device comprising the light emitting device according to claim 4 . a first step of mixing the surface-modifying material and water to obtain a mixture;
a second step of mixing the mixture, inorganic oxide particles, and a hydrophobic solvent to obtain a dispersion in which the inorganic oxide particles are dispersed;
a third step of removing at least a portion of the water from the dispersion;
and a fourth step of heating the dispersion. 7. The method for producing a dispersion liquid according to claim 6, wherein in the third step, a hydrophobic solvent is further added to the dispersion liquid.

Images