JP2017011130A - Solution for dispersing high specific gravity particles, phosphor dispersion liquid including the solution, light-emitting device, and method for manufacturing the solution - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solution for dispersing high specific gravity particles, capable of: dispersing the high specific gravity particles, such as phosphor particles, pigments and metal particles, without precipitating them; preventing discoloration from occurring in a layer obtained from the solution; and preventing current leakage in a device including the layer.SOLUTION: A solution for dispersing high specific gravity particles comprises: plate-like swollen particles; and a solvent. Interlayer cations of the plate-like swollen particles are ammonium-based ions represented by a predetermined formula.SELECTED DRAWING: None

Description

  The present invention relates to a solution for dispersing high specific gravity particles, a phosphor dispersion liquid containing the same, a light emitting device, and a method for manufacturing the same.

  In a slurry containing metal particles, a phosphor dispersion liquid containing phosphor particles, and the like, there is a problem that particles with high specific gravity such as metal particles and phosphor particles are likely to settle. Therefore, conventionally, sedimentation of high specific gravity particles has been suppressed by adding various anti-settling agents to these dispersions or stirring the solution before use.

  Further, Patent Document 1 and Patent Document 2 include suppressing the sedimentation of phosphor particles by including lipophilic swelling particles (lipophilic smectite, etc.) in a phosphor dispersion liquid containing phosphor particles and a solvent. Is described.

International Publication No. 2012/090999 JP 2004-153109 A

  However, in the case where the wavelength conversion layer of the light emitting device is prepared using a phosphor dispersion liquid containing lipophilic smectite as shown in Patent Document 1 and Patent Document 2, the color of the wavelength conversion layer changes over time, or the light emitting device However, there is a problem that current leakage is likely to occur.

  Further, plate-like swollen particles whose interlayer cations are metal ions are also known as anti-settling agents for high specific gravity particles. However, even when such plate-like swollen particles are used in a phosphor dispersion liquid or the like, current leakage is likely to occur in the light emitting device. In addition, when a plate-like swollen particle in which the lipophilic smectite or the interlayer cation is a metal ion is applied to a slurry of metal particles to form a conductive layer, in a device including the conductive layer, current leakage, etc. It was easy to occur.

  The present invention has been made in view of the above problems. That is, an object of the present invention is to disperse various high specific gravity particles such as phosphor particles, pigments, metal particles and the like without settling, and further, in a layer obtained from the solution, a color change hardly occurs, and an apparatus including the layer In the above, it is an object to provide a solution for dispersing high specific gravity particles, in which current leakage or the like hardly occurs.

（一般式（１）におけるＲ_１〜Ｒ_４は、それぞれ独立に、水素原子、炭素原子の数が１〜４５のアルキル基、炭素原子の数が１〜４５のポリ（オキシアルキレン）含有基、炭素原子の数が１〜４５のヒドロキシ基含有アルキル基であり、Ｒ_１〜Ｒ_４が含む炭素原子の合計数は０以上４５以下である） That is, the first of the present invention is the following solution for dispersing high specific gravity particles and a phosphor dispersion containing the same.
[1] A solution for dispersing high specific gravity particles, comprising plate-like swollen particles and a solvent, wherein the interlayer cation of the plate-like swollen particles is an ammonium ion represented by the following general formula (1).

(R _{1 to} R ₄ in the general formula (1) are each independently a hydrogen atom, an alkyl group having 1 to 45 carbon atoms, a poly (oxyalkylene) -containing group having 1 to 45 carbon atoms, (It is a hydroxy group-containing alkyl group having _{1 to} 45 carbon atoms, and the total number of carbon atoms contained in R _{1 to} R ₄ is 0 or more and 45 or less)

[2] The solution for dispersing high specific gravity particles according to [1], wherein the total number of carbon atoms contained in R _{1 to} R ₄ in the general formula (1) is 0 or more and 30 or less.
[3] The solution for dispersing high specific gravity particles according to [1] or [2], in which R _{1 to} R ₄ in the general formula (1) are all hydrogen atoms.
[4] The high specific gravity according to any one of [1] to [3], wherein the amount of the plate-like swollen particles is 0.5% by mass or more and 20% by mass or less with respect to the total amount of the solution for dispersing high specific gravity particles. Particle dispersion solution.

[5] The solution for dispersing high specific gravity particles according to any one of [1] to [4], further including inorganic oxide particles.
[6] The solution for dispersing high specific gravity particles according to [5], wherein the amount of the inorganic oxide particles with respect to the total amount of the solution for dispersing high specific gravity particles is 0.5% by mass or more and 20% by mass or less.
[7] The solution for dispersing high specific gravity particles according to [5] or [6], wherein the inorganic oxide particles are surface-modified with a hydrocarbon group having 1 to 45 carbon atoms.
[8] The solution for dispersing high specific gravity particles according to any one of [1] to [7], wherein the solvent contains a polyhydric alcohol.
[9] A phosphor dispersion liquid comprising phosphor particles and the solution for dispersing high specific gravity particles according to any one of [1] to [8].

（一般式（１）におけるＲ_１〜Ｒ_４は、それぞれ独立に、水素原子、炭素原子の数が１〜４５のアルキル基、炭素原子の数が１〜４５のポリ（オキシアルキレン）含有基、炭素原子の数が１〜４５のヒドロキシ基含有アルキル基であり、Ｒ_１〜Ｒ_４が含む炭素原子の合計数は０以上４５以下である） The second of the present invention is to provide the following method for manufacturing a light emitting device and the light emitting device.
[10] A method for manufacturing a light-emitting device comprising a substrate, a light-emitting element disposed on the substrate, and a wavelength conversion layer covering the light-emitting element, and applying the phosphor dispersion liquid according to [9] The manufacturing method of the light-emitting device including the process to do.
[11] A light emitting device including a substrate, a light emitting element disposed on the substrate, and a wavelength conversion layer covering the light emitting element, wherein the wavelength conversion layer includes phosphor particles and plate-like swelling particles. A light emitting device comprising an interlayer cation of the plate-like swollen particles, which is an ammonium ion represented by the following general formula (1).

(R _{1 to} R ₄ in the general formula (1) are each independently a hydrogen atom, an alkyl group having 1 to 45 carbon atoms, a poly (oxyalkylene) -containing group having 1 to 45 carbon atoms, (It is a hydroxy group-containing alkyl group having _{1 to} 45 carbon atoms, and the total number of carbon atoms contained in R _{1 to} R ₄ is 0 or more and 45 or less)

[12] The light-emitting device according to [11], wherein the total number of carbon atoms included in R _{1 to} R ₄ in the general formula (1) is 0 or more and 30 or less.
[13] The light-emitting device according to [11] or [12], wherein R _{1 to} R ₄ in the general formula (1) are all hydrogen atoms.
[14] The light emitting device according to any one of [11] to [13], wherein the wavelength conversion layer further includes inorganic oxide particles.
[15] The light emitting device according to [14], wherein the inorganic oxide particles are surface-modified with a hydrocarbon group having 1 to 45 carbon atoms.

  According to the solution for dispersing high specific gravity particles of the present invention, it is possible to disperse various high specific gravity particles such as phosphor particles, pigments and metal particles without settling. Furthermore, in a layer obtained from the high specific gravity particle dispersion solution, discoloration over time hardly occurs, and current leakage or the like hardly occurs in an apparatus including the layer.

It is a schematic sectional drawing which shows an example of the light-emitting device of this invention. It is a schematic sectional drawing which shows the other example of the light-emitting device of this invention.

  Hereinafter, the present invention will be described in detail. However, the present invention is not limited to the following embodiments, and various modifications can be made without departing from the scope of the invention. In addition, in this application, "-" showing a numerical range is used by the meaning containing the numerical value described before and behind that as a lower limit and an upper limit.

1. TECHNICAL FIELD The present invention relates to a solution for uniformly dispersing particles having a high specific gravity. The high specific gravity particle dispersion solution of the present invention includes at least plate-like swollen particles and a solvent. . The “plate-like swollen particles” in the present invention have a structure in which thin layers made of silicic acid or aluminum oxide are stacked, and a cation (hereinafter also referred to as “interlayer cation”) between the layers. It is particle | grains which have. The interlayer cations of the plate-like swollen particles are generally metal ions, but the interlayer cations of the plate-like swollen particles contained in the solution for dispersing high specific gravity particles of the present invention are ammonium ions having a specific structure. is there.

  As described above, in order to improve the dispersion stability of high specific gravity particles in a solution containing high specific gravity particles (hereinafter also referred to as “high specific gravity particle-containing liquid”), it has been studied to add plate-like swollen particles. I came. When plate-like swollen particles are contained in the high specific gravity particle-containing liquid, the viscosity of the high specific gravity particle-containing liquid increases due to swelling of the plate-like swollen particles, and sedimentation of the high specific gravity particles is suppressed. However, when the interlayer cation of the plate-like swollen particles is a metal ion, the metal ion is easy to migrate. As a result, in an apparatus including a layer obtained from the high specific gravity particle-containing liquid, current leakage due to metal ions was likely to occur.

  On the other hand, when the interlayer cation of the plate-like swollen particles contains an organic group (particularly, the total number of carbons in the interlayer ions is 50 or more), the layer obtained from the high specific gravity particle-containing liquid is easily discolored over time. Even in a device including a layer, current leakage was likely to occur. The interlayer cation of the conventionally known lipophilic plate-like swollen particles contains a relatively large number of carbon atoms. And the group (for example, alkyl group etc.) containing the said carbon atom is easy to be decomposed | disassembled with a heat | fever or light. Therefore, it is presumed that the free substance generated by the decomposition causes discoloration or the free substance becomes a carrier and induces current leakage.

  In contrast, in the present invention, the interlayer cation of the plate-like swollen particles is a specific ammonium ion, and the number of carbons contained in the interlayer cation is 45 or less. Therefore, the interlayer cation of the plate-like swollen particles is not easily decomposed by heat or light, and the layer obtained from the high specific gravity particle dispersion solution is hardly colored. Further, current leakage hardly occurs in the device including the layer. Moreover, according to the solution for dispersing high specific gravity particles containing the plate-like swollen particles, the high specific gravity particles can be stably dispersed without settling. Therefore, the high specific gravity particle dispersion solution of the present invention is very useful as a solution for dispersing various high specific gravity particles such as metal particles and phosphor particles.

1-1. Plate-like swollen particles The plate-like swollen particles contained in the solution for dispersing high specific gravity particles according to the present invention are those in which the interlayer cation is a specific ammonium ion and swells in a solvent, and the viscosity of the solution for dispersing high specific gravity particles The particles are not particularly limited as long as the particles can increase the particle size. The plate-like swollen particles can be, for example, particles obtained by substituting interlayer cations of a layered clay mineral having a layered crystal structure with specific ammonium ions.

  Layered clay minerals are generally classified into 1: 1 type clay minerals and 2: 1 type clay minerals. The 1: 1 type clay mineral has a layer in which a unit crystal layer (tetrahedral layer) made of silicic acid and a unit crystal layer or the like (octahedral layer) made of aluminum are bonded at a ratio of 1: 1. On the other hand, in the 2: 1 type clay mineral, a unit crystal layer (octahedral layer) containing aluminum, magnesium oxide, or iron is sandwiched between two unit crystal layers (tetrahedral layer) made of silicic acid. Having a layer.

  In such a layered clay mineral, a part of the unit crystal layer is isomorphously substituted (for example, silicon in the layer made of silicic acid is replaced with Al or Fe (III), or part of the layer made of aluminum is In general, Si or Fe is substituted, or Mg in a layer made of magnesium oxide is substituted with Li), and each layer is negatively charged. Various cations (interlayer cations) are adsorbed between these layers.

Here, in a general layered clay mineral, the interlayer cation is composed of metal ions such as Na ⁺ , K ⁺ , Ca ²⁺ , Mg ²⁺ , and Al ^2+, but is included in the solution for dispersing high specific gravity particles of the present invention. In the plate-like swollen particles, the interlayer cations are replaced with ammonium ions described later.

  The ease of substitution of the cation of the layered clay mineral from a metal ion to an ammonium ion or the like is referred to as base substitution ability or cation exchange ability. The cation exchange capacity of the layered clay mineral generally varies depending on the type of the layered clay mineral, and the cation exchange capacity increases as the layered clay mineral has a larger specific surface area.

  Furthermore, the cation exchange ability is higher when the negative charge of the layered clay mineral is distributed widely on the surface of the crystal layer than when the negative charge is localized on the surface of the crystal layer. That is, in the 2: 1 type clay mineral, the cation exchange ability is obtained when the octahedral layer of Al—O, Mg—O, etc. sandwiched between two tetrahedral layers of silicic acid has isomorphous substitution. Highest. When the octahedral layer of 2: 1 type clay mineral is isomorphously substituted, the distance between the negative charge and the exchangeable cation is moderately separated and the electrostatic interaction is relatively weak. Therefore, the clay mineral forms an outer sphere complex that easily exchanges cations. On the other hand, even in the case of 2: 1 type clay mineral, when there is isomorphous substitution in the tetrahedral layer made of silicic acid which is the outermost layer, the expression of negative charges is local. And since the distance of the negative charge and exchangeable cation by isomorphous substitution is near, electrostatic interaction is strong. Therefore, in the layered clay mineral, an inner sphere complex that hardly exchanges cations is formed, and the cation exchanging ability is lowered.

  On the other hand, in the 1: 1 type clay mineral, the tetrahedral layer and the octahedral layer made of silicic acid are the outermost layers, respectively, and thus the expression of negative charges is localized at the same type substitution site. Moreover, since the distance between the negative charge and the exchangeable cation is short, electrostatic interaction is strong. Therefore, an inner sphere complex that is difficult to exchange cation is formed, and the cation exchange ability tends to be low.

  Accordingly, the plate-like swollen particles contained in the high specific gravity particle dispersion solution of the present invention may have any of the above-mentioned 1: 1 type layered clay mineral and 2: 1 type layered clay mineral. It is preferable that the 2: 1 type layered clay mineral is substituted with an interlayer cation.

  Specific examples of the 1: 1 type layered clay mineral include natural or synthetic minerals such as kaolinite and halosite. Specific examples of 2: 1 type layered clay minerals include natural or synthetic minerals, such as natural hectorite, saponite, stevensite, hydelite, montmorillonite, nontrite, bentonite, and laponite; Na Swellable mica group clay minerals such as type tetrasilicic fluorine mica, Li type tetrasilic fluorine mica, Na type fluorine teniolite, Li type fluorine teniolite; muscovite, phlogopite, fluorine phlogopite, sericite, potassium tetrasilicon mica And non-swellable mica group clay minerals, and vermiculite.

  In addition, the 2: 1 type layered clay mineral is preferably a smectite group or vermiculite having an isomorphous substitution in an octahedral layer, and particularly preferably a smectite group. The smectite group has a relatively weak charge of the unit crystal layer relative to other layered clay minerals, and has a high cation exchange capacity. The smectite group is also preferable from the viewpoint of high transparency and difficulty in coloring the layer obtained from the solution for dispersing high specific gravity particles. In particular, the synthetic smectite group has few impurities and is excellent in transparency.

上記式（１）において、Ｒ_１〜Ｒ_４は、それぞれ独立に、水素原子、炭素原子の数が１〜４５のアルキル基、炭素原子の数が１〜４５のポリ（オキシアルキレン）含有基、または炭素原子の数が１〜４５のヒドロキシ基含有アルキル基であり、かつＲ_１〜Ｒ_４が含む炭素の数の合計が０〜４５である。Ｒ_１〜Ｒ_４が含む炭素の数の合計は、より好ましくは０〜３０である。Ｒ_１〜Ｒ_４に含まれる炭素原子の数が少ないほうが、耐熱性の観点から好ましい。したがって、板状膨潤粒子の層間陽イオンのＲ_１〜Ｒ_４がいずれも水素原子である、つまりアンモニウムイオンであることが特に好ましい。 Here, the interlayer cation of the plate-like swollen particles contained in the solution for dispersing high specific gravity particles of the present invention is an ammonium ion having a structure represented by the following general formula (1).

In the above formula (1), R _{1 to} R ₄ are each independently a hydrogen atom, an alkyl group having 1 to 45 carbon atoms, a poly (oxyalkylene) -containing group having 1 to 45 carbon atoms, Alternatively, the number of carbon atoms is a hydroxy group-containing alkyl group having ₁ to 45, and the total number of carbons contained in R _{1 to} R ₄ is 0 to 45. The total number of carbons contained in R _{1 to} R ₄ is more preferably 0 to 30. A smaller number of carbon atoms contained in R _{1 to} R ₄ is preferable from the viewpoint of heat resistance. Therefore, it is particularly preferable that R _{1 to} R ₄ of the interlayer cations of the plate-like swollen particles are all hydrogen atoms, that is, ammonium ions.

The number of carbon atoms of the alkyl group that may be R _{1 to} R ₄ is more preferably 1 to 30, and further preferably 1 to 10. The alkyl group may have a linear, branched, or cyclic structure. Examples of alkyl groups include, for example, methyl, ethyl, propyl, isopropyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, Tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group and the like are included. The alkyl group is preferably a methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group or decyl group.

The poly (oxyalkylene) -containing group that can be R _{1 to} R ₄ is not particularly limited as long as it is a group containing a poly (oxyalkylene) group. The number of carbon atoms of the poly (oxyalkylene) -containing group is more preferably 1-30, and still more preferably 1-10. The poly (oxyalkylene) -containing group can be, for example, a group represented by the general formula (C _m H _2m —O) _k —R ₅ . m is an integer of 1 to 45, and R ₅ is a hydrogen atom or an alkyl group. K is 1 to 45. However, the total number of carbon atoms contained in the above group is 45 or less. Examples of the poly (oxyalkylene) -containing group include a polyethyleneoxy group represented by (CH ₂ —CH ₂ —O) _n —H, and (CH ₂ —CH ₂ —CH ₂ —O) _p —H. Polypropyleneoxy groups and the like. n is preferably 1 to 22, and preferably 1 to 15. On the other hand, p is preferably 1 to 15, more preferably 1 to 10.

Furthermore, the number of carbon atoms of the hydroxy group-containing alkyl group that can be R _{1 to} R ₄ is more preferably 1 to 30, and still more preferably 1 to 10. The hydroxy group-containing alkyl group has a structure in which at least one hydroxyl group is bonded to the alkyl group. Hydroxy group-containing alkyl group The alkyl contained in the hydroxy group-containing alkyl group may have a linear, branched, or cyclic structure. The hydroxy group-containing alkyl group can be, for example, a group derived from a primary, secondary, or tertiary alcohol. Examples of hydroxy group-containing alkyl groups include hydroxymethyl group, 1-hydroxyethyl group, 2-hydroxyethyl group, 1-hydroxy-n-propyl group, 2-hydroxy-n-propyl group, 3-hydroxy-n- Propyl group, 1-hydroxyisopropyl group, 2-hydroxyisopropyl group, 1-hydroxy-n-butyl group, 2-hydroxy-n-butyl group, 3-hydroxy-n-butyl group, 4-hydroxy-n-butyl group Etc. are included.

  The plate-like swollen particles containing the ammonium ion represented by the general formula (1) as an interlayer cation can be obtained, for example, by reacting the layered clay mineral particle with the salt of the ammonium ion. Specifically, a layered clay mineral whose interlayer cation is a metal ion and a salt of the ammonium ion are dispersed or dissolved in water. Then, after sufficiently shaking the mixed solution, the supernatant is removed by centrifugation. This process is repeated for the obtained layered clay mineral. By this step, the interlayer cation is replaced from metal ion to ammonium ion. In addition, the metal cation (interlayer cation) originally contained in the layered clay mineral and the counter anion contained in the cation source are removed together with water.

The counter anion in the salt of an ammonium ion is not particularly limited, and may be, for example, Cl ⁻ , Br ⁻ , NO ₃ ⁻ , OH ⁻ , CH ₃ COO ⁻ or the like.

  Examples of ammonium ion salts include ammonium chloride, methylammonium chloride, polyoxypropylene / trialkylammonium chloride, polyoxypropylene / trialkylammonium bromide, di (polyoxypropylene) / dialkylammonium chloride, di (polyoxy). Propylene) .dialkylammonium bromide, tri (polyoxypropylene) .alkylammonium chloride, tri (polyoxypropylene) .alkylammonium bromide and the like.

  Here, the plate-like swollen particles are preferably contained in an amount of 0.5 to 20% by mass, more preferably 0.5 to 10.0% by mass, based on the total amount of the solution for dispersing high specific gravity particles of the present invention. More preferably, it is 0.5-2.0 mass%. When the amount of the plate-like swollen particles is 0.5% by mass or more, the viscosity of the solution for dispersing high specific gravity particles is likely to be sufficiently increased by the plate-like swollen particles. As a result, when high specific gravity particles are dispersed in a solution for dispersing high specific gravity particles, the dispersion stability of the high specific gravity particles tends to increase. On the other hand, when the amount of the plate-like swelling particles is 20% by mass or less, the viscosity of the high specific gravity particle dispersion solution is hardly excessively increased, and the fluidity of the high specific gravity particle dispersion solution can be sufficiently maintained.

  The shape of the plate-like swollen particles is not particularly limited, but the average particle diameter is preferably 0.3 to 15.0 μm, more preferably 0.5 to 7.0 μm, and still more preferably 1.0. ˜5.0 μm. The average particle diameter is measured by a Coulter counter method. When the average particle diameter of the plate-like swollen particles is 15.0 μm or less, coloring and light transmittance are unlikely to occur when the solution for dispersing high specific gravity particles is used for various applications. On the other hand, when the average particle size of the plate-like swollen particles is 0.3 μm or more, the viscosity of the solution for dispersing high specific gravity particles is easily increased by the plate-like swollen particles.

1-2. Solvent The solvent contained in the solution for dispersing high specific gravity particles is not particularly limited as long as the plate-like swollen particles can be uniformly dispersed, and may be either water or an organic solvent. Examples of organic solvents include monohydric alcohols such as methanol, ethanol, 1-propanol, isopropyl alcohol, butanol, ethylene glycol, propylene glycol, diethylene glycol, glycerin, 1,3-butanediol, 1,4-butanediol. A polyhydric alcohol having a valence of 2 or more is included. The solution for dispersing high specific gravity particles may contain only one type of solvent or two or more types of solvents.

  Here, it is particularly preferable that the solvent contains a polyhydric alcohol. When polyhydric alcohol is contained in the solution for dispersing high specific gravity particles, the viscosity of the solution for dispersing high specific gravity particles tends to increase moderately, and the dispersion stability when the high specific gravity particles are dispersed tends to increase. Moreover, when the below-mentioned inorganic oxide particle is contained in the solution for high specific particle dispersion, if the solvent contains a polyhydric alcohol, the affinity of the inorganic oxide particle is likely to increase.

  Moreover, when a solvent is an organic solvent, it is preferable that the number of the carbon atoms contained in one molecule of the said organic solvent is 1-11, More preferably, it is 2-8. When the number of carbon atoms contained in one molecule of the organic solvent is within the above range, the affinity with the plate-like swollen particles and the inorganic oxide particles described later tends to be increased.

  In addition, it is preferable that the boiling point of an organic solvent is 150 degreeC or more, and it is preferable that it is 250 degrees C or less. When the boiling point of the organic solvent is 150 ° C. or higher, the storage stability of the solution for dispersing high specific gravity particles is increased. On the other hand, when the boiling point of the organic solvent is 250 ° C. or lower, various layers are formed using a solution for dispersing high specific gravity particles or a liquid containing high specific gravity particles in which high specific gravity particles are dispersed in a solution for dispersing high specific gravity particles. In addition, the solvent can be efficiently dried.

  The solvent is preferably contained in an amount of 1 to 99% by mass, more preferably 50 to 95% by mass, and still more preferably 70 to 90% by mass with respect to the total amount of the solution for dispersing high specific gravity particles. When the amount of the solvent is within the above range, the concentration of the high specific gravity particle dispersion solution can be kept within a desired range.

1-3. Inorganic oxide particles The high specific gravity particle dispersion solution of the present invention may contain inorganic oxide particles, if necessary. When inorganic oxide particles are contained in the solution for dispersing high specific gravity particles, the viscosity of the solution for dispersing high specific gravity particles tends to increase, and the dispersion stability when the particles of high specific gravity are dispersed in the solution for dispersing high specific gravity particles tends to increase. .

Examples of the inorganic oxide particles include SiO ₂ , Al ₂ O ₃ , ZnO, TiO ₂ , ZrO and the like. The solution for dispersing high specific gravity particles may contain only one kind of inorganic oxide particles or two or more kinds.

  The average particle size of the inorganic oxide particles is not particularly limited as long as it is a particle size that can be uniformly dispersed in the above-mentioned solvent, but is preferably 0.1 to 10.0 μm, more preferably 3.0. It is -7.0 micrometers, More preferably, it is 4.0-6.0 micrometers. The average particle diameter is measured by a Coulter counter method. When the average particle size of the inorganic oxide particles is 10.0 μm or less, the inorganic oxide particles can be easily dispersed in the solvent. Further, when the solution for dispersing high specific gravity particles is used for various applications, coloring derived from inorganic oxide particles and a decrease in light transmittance are unlikely to occur. On the other hand, when the average particle size of the inorganic oxide particles is 0.1 μm or more, the viscosity of the solution for dispersing high specific gravity particles is easily increased by the inorganic oxide.

  In addition, the inorganic oxide particle may not be surface-treated and may have a number of —OH groups on the surface. On the other hand, the inorganic oxide particles may be hydrophobized. Although the surface treatment method is not particularly limited, for example, the surface preferably has a hydrocarbon group having 1 to 45 carbon atoms, more preferably 1 to 30, and further preferably 1 to 15. When a hydrocarbon group is contained on the surface of the inorganic oxide particles, the affinity between the inorganic oxide particles and the solvent, particularly the polyhydric alcohol, etc., is likely to increase in the solution for dispersing high specific gravity particles. Specifically, the OH group present on the surface of the inorganic oxide particle has an affinity for the OH group of the polyhydric alcohol. On the other hand, the hydrocarbon group on the surface of the inorganic oxide particles and the alkylene group of the polyhydric alcohol have an affinity. Therefore, the viscosity of the solution for dispersing high specific gravity particles is easily increased sufficiently, and the dispersion stability when the high specific gravity particles are dispersed is easily increased.

  Here, the method for introducing a hydrocarbon group having 1 to 45 carbon atoms into the surface of the inorganic oxide particles is not particularly limited. For example, monomethyltrimethoxysilane, dimethyldimethoxysilane, trimethylmethoxysilane, monoethyltrimethoxysilane, diethyldimethoxysilane, triethylmethoxysilane, propyltrimethoxysilane, isopropyltrimethoxysilane and other alkyl alkoxysilane compounds, or hexamethyldisilazane It can be a method of treating an inorganic oxide with a hydrophobic compound such as.

  Below, although an example of the method of hydrophobizing the surface of an inorganic oxide particle with the said hydrophobic compound is shown, the surface treatment method of an inorganic oxide particle is not limited to the said method. First, a hydrophobic compound is applied to the inorganic oxide particles. The application method of the hydrophobic compound is not particularly limited, but when applied by a spray method, the hydrophobic compound tends to adhere uniformly to the surface of the inorganic oxide particles. In addition, when applying the hydrophobic compound, it is preferable to apply water and alcohol together by spraying. The hydrophobic compound is hydrolyzed by water or alcohol, and easily reacts with —OH groups on the surface of the inorganic oxide particles. Thereafter, the inorganic oxide particles having the hydrophobic compound attached to the surface are heated in an inert gas atmosphere. The heating temperature is not particularly limited, but can usually be about 150 to 250 ° C. By heating, the hydrolyzate of the hydrophobic compound and the —OH group on the surface of the inorganic fine particle undergo a condensation reaction, and the hydrophobic group is introduced onto the surface of the inorganic oxide particle.

  In addition, you may apply | coat a non-reactive silicone oil to the inorganic oxide particle surface as needed before the hydrophobization process by the said hydrophobic compound. When silicone oil is applied to the surface of the inorganic oxide particles, the hydrophobicity of the inorganic oxide particles can be further increased.

  Here, the amount of the inorganic oxide particles contained in the high specific gravity particle dispersion solution is preferably 0.5 to 20% by mass, more preferably 0.5 to 15% by mass, and still more preferably 0. 5 to 10% by mass. When the amount of the inorganic oxide particles is 20% by mass or less, the amount of the plate-like swelling particles and the solvent is relatively increased, and the stability of the high specific gravity particle dispersion solution is likely to be increased. Moreover, when the amount of the inorganic oxide particles is 20% by mass or less, when the solution for dispersing high specific gravity particles is used for various applications, coloring from the inorganic oxide particles and a decrease in light transmittance are unlikely to occur. On the other hand, when the amount of the inorganic oxide particles is 0.5% by mass or more, the viscosity of the solution for dispersing high specific gravity particles is likely to be sufficiently increased, and sedimentation of the high specific gravity particles occurs when the high specific gravity particles are dispersed. It becomes difficult.

1-4. Physical Properties of High Density Particle Dispersion Solution The viscosity of the high density particle dispersion solution is preferably 10 to 1000 Pa · s, more preferably 30 to 600 Pa · s, and still more preferably 50 to 300 Pa · s. . When the viscosity of the solution for dispersing high specific gravity particles is in the above range, the high specific gravity particles are difficult to settle when the high specific gravity particles are dispersed. The viscosity of the solution for dispersing high specific gravity particles can be adjusted by the amount of solvent, the amount of plate-like swollen particles, the amount of inorganic oxide particles, and the like.

1-5. Method for preparing high density particle dispersion solution The method for preparing the above high density particle dispersion solution is not particularly limited. For example, a method of mixing a solvent, plate-like swollen particles, inorganic oxide particles and the like at a time and dispersing them may be used. Moreover, the method of mixing any one among plate-like swelling particle | grains or inorganic oxide particle | grains in a solvent, and mixing the other later may be sufficient.

  Dispersion of the plate-like swollen particles and inorganic oxide particles in the solvent can be carried out with a stirring mill, a blade kneading and stirring device, a thin-film swirling disperser, a high-pressure impact dispersing device, a rotation and revolution mixer, and the like.

  Specific examples of the above-mentioned apparatus include known ultra turrax (manufactured by IKA Japan), TK homomixer (manufactured by Primix), TK pipeline homomixer (manufactured by Primix), TK Philmix (manufactured by Primix), Claremix. (M-Technics), Claire SS5 (M-Technics), Cavitron (Eurotech), media flow stirrers such as Fine Flow Mill (Pacific Kiko), Viscomill (Imex), Apex Mill (manufactured by Kotobuki Kogyo Co., Ltd.), Star Mill (manufactured by Ashizawa, Finetech), DMPA / S Super Flow (manufactured by Nihon Eirich), MPP Mill (manufactured by Inoue Seisakusho), spike mill (manufactured by Inoue Seisakusho), Mighty Mill ( Media stirrer such as Inoue Seisakusho Co., Ltd. and SC Mill (Mitsui Mining Co., Ltd.) (Manufactured by Sugino Machine Co., Ltd.) and Altimizer machine, Nanomizer (manufactured by Yoshida Kikai), includes a high-pressure impact type dispersing device, etc., such as NANO 3000 (manufactured by Bitsubusha). In addition, a rotating / revolving mixer such as Awatori Netaro (manufactured by Shinky Corp.) and an ultrasonic dispersing apparatus are also suitable for preparing a solution for dispersing high specific gravity particles.

1-6. Applications The high specific gravity particle-dispersing solution of the present invention is unlikely to settle when high specific gravity particles are added. Therefore, it is suitable as a solution in which various high specific gravity particles are dispersed. The method of using the high specific gravity particle dispersion solution is not particularly limited. For example, after dispersing high specific gravity particles (for example, pigments, phosphor particles, metal particles, etc.) in the high specific gravity particle dispersion solution, the dispersion liquid is directly used as an ink. Alternatively, it may be used as a phosphor dispersion, a polishing slurry, a metal wiring forming composition, or the like. On the other hand, after dispersing high specific gravity particles in a solution for dispersing high specific gravity particles, the dispersion may be further mixed with a resin, a ceramic precursor or the like and used for various applications.

  The method for dispersing the high specific gravity particles in the solution for dispersing high specific gravity particles is not particularly limited. For example, the high specific gravity particles can be dispersed with a stirring mill, a blade kneading and stirring device, a thin-film swirling disperser, a high-pressure impact dispersion device, a rotation and revolution mixer, and the like. it can.

  The kind of high specific gravity particles to be dispersed in the high specific gravity particle dispersion solution is not particularly limited, and may be various particles such as pigments, phosphor particles, metal particles, etc., preferably particles having a specific gravity of 1.5 to 11 It is.

  The average particle size of the high specific gravity particles is not particularly limited, but is preferably about 0.01 to 100 μm, more preferably 5 to 50 μm. When the average particle diameter of the high specific gravity particles is within the above range, the high specific gravity particles can be uniformly dispersed by the high specific gravity particle dispersion solution. The average particle diameter is measured by a Coulter counter method.

  Furthermore, the amount of the high specific gravity particles to be added is preferably 70 parts by mass or less, more preferably 50 parts by mass or less with respect to 100 parts by mass of the solution for dispersing high specific gravity particles. If the amount of high specific gravity particles is excessive, it may be difficult to uniformly disperse all the high specific gravity particles with the high specific gravity particle dispersion solution. Can do.

2. Light emitting device The above-mentioned solution for dispersing high specific gravity particles can be applied to a phosphor dispersion liquid for forming the wavelength conversion layer of the light emitting device of the present invention. An example of the light-emitting device of the present invention is shown in FIGS. The light emitting device 100 of the present invention includes a substrate 1, a light emitting element 2 disposed on the substrate 1, and a wavelength conversion layer 3 covering the light emitting element 2. The wavelength conversion layer 3 is not particularly limited in its formation position as long as light with a specific wavelength emitted from the light emitting element 2 can be converted into light with another wavelength. For example, as shown in FIG. 1, it may be formed so as to be in contact with the light emitting element 2. On the other hand, as shown in FIG. 2, the light emitting element 2 may be formed with a gap. In the light emitting device 100 of FIG. 2, the wavelength conversion layer 3 is formed on one surface of the sealing substrate 4 facing the light emitting element 2.

  Here, the wavelength conversion layer 3 of the light emitting device 100 of the present invention includes phosphor particles and plate-like swollen particles, and the interlayer cation of the plate-like swollen particles is represented by the general formula (1). It is an ammonium ion represented.

  As described above, in the wavelength conversion layer including the conventional plate-like swollen particles, the wavelength conversion layer is discolored over time due to decomposition of interlayer cations of the plate-like swollen particles, or includes the wavelength conversion layer. In the light emitting device, there is a problem that current leakage is likely to occur. On the other hand, in the light emitting device of the present invention, the interlayer cation of the plate-like swollen particles contained in the wavelength conversion layer is a specific ammonium ion, and the number of carbons contained in the interlayer cation is 45 or less. Therefore, the interlayer cations of the plate-like swollen particles are not easily decomposed by heat or light, and the wavelength conversion layer is not easily discolored. In addition, since it is difficult for decomposition products of interlayer cations or the like to occur, current leakage hardly occurs in the light emitting device. Moreover, since the specific plate-like swollen particles are contained in the wavelength conversion layer, an effect that the strength of the wavelength conversion layer is increased is also obtained. Furthermore, the plate-like swollen particles have high affinity with the organic solvent, and the plate-like particles are uniformly arranged in the wavelength conversion layer. In the wavelength conversion layer, the plate-like layers of the plate-like swelling particles are easily arranged in parallel. Therefore, in the light emitting device of the present invention, the wavelength conversion layer has high gas barrier properties and moisture resistance, and sulfidation and oxidation of electrodes and metal wires included in the light emitting device, and discoloration associated therewith are suppressed.

  Here, the kind of the light emitting element included in the light emitting device of the present invention is not particularly limited, and may be a semiconductor laser element, a light emitting diode (LED) element, or the like. Hereinafter, the light-emitting device of the present invention will be described by taking the device shown in FIGS. 1 and 2 (when the light-emitting element 2 is an LED element) as an example, but the light-emitting device 100 of the present invention is an LED element. It is not limited to a certain device.

2-1. Substrate The substrate 1 is a member for supporting the LED element 2. As shown in FIG. 1 and FIG. 2, an electrode 11 made of a metal is usually formed on the substrate 1. The electrode 11 has a function of supplying electricity to the LED element 2 from a power source (not shown) arranged outside the substrate 1. In addition, the electrode 11 may function as a reflecting plate that reflects the light emitted from the LED element 2 to the light extraction surface side of the light emitting device 100. The shape of the electrode 11 is not particularly limited, and is appropriately selected according to the type and use of the light emitting device 100.

  The board | substrate 1 may be flat form and may have a cavity (concave part) as FIG.1 and FIG.2 shows. When the substrate 1 has a cavity, the shape of the cavity is not particularly limited. For example, a truncated cone shape, a truncated pyramid shape, a cylindrical shape, a prismatic shape, or the like may be used.

  The substrate 1 preferably has insulating properties and heat resistance, and is preferably made of a ceramic resin or a heat resistant resin. Examples of the heat resistant resin include liquid crystal polymer, polyphenylene sulfide, aromatic nylon, epoxy resin, hard silicone resin, polyphthalic acid amide and the like.

  The substrate 1 may contain an inorganic filler. The inorganic filler can be titanium oxide, zinc oxide, alumina, silica, barium titanate, calcium phosphate, calcium carbonate, white carbon, talc, magnesium carbonate, boron nitride, glass fiber, and the like.

  The method for producing the substrate 1 having the electrode 11 is not particularly limited, and is generally obtained by integrally molding a lead frame having a desired shape and a resin.

2-2. LED element The LED element 2 is an element that is electrically connected to the electrode 11 formed on the substrate 1 and emits light of a specific wavelength. The wavelength of the light emitted from the LED element 2 is not particularly limited. The LED element 2 may be, for example, an element that emits blue light (light of about 420 nm to 485 nm) or an element that emits ultraviolet light. Furthermore, an element that emits green light, red light, or the like may be used.

  The configuration of the LED element 2 is not particularly limited. When the LED element 2 is an element that emits blue light, the LED element 2 includes an n-GaN compound semiconductor layer (cladding layer), an InGaN compound semiconductor layer (light emitting layer), and a p-GaN compound semiconductor layer. It may be a laminate of (clad layer) and a transparent electrode layer.

  Moreover, the shape in particular of the LED element 2 is not restrict | limited, For example, it may have a light emission surface of 200-300 micrometers x 200-300 micrometers. Moreover, the height of the LED element 2 is about 50-200 micrometers normally. The LED element 2 may be one in which light is extracted not only from the top surface but also from the side surface and the bottom surface. In the light emitting device 100 illustrated in FIG. 1, only one LED element 2 is disposed on the substrate 1, but a plurality of LED elements 2 may be disposed on the substrate 1.

  The connection method between the LED element 2 and the electrode 11 is not particularly limited. For example, the LED element 2 and the electrode 11 may be connected via a metal wire 12 as shown in FIG. Moreover, the LED element 2 and the electrode 11 may be connected via a protruding electrode (not shown). A mode in which the LED element 2 and the electrode 11 are connected via the metal wire 12 is referred to as a wire bonding type. On the other hand, a mode in which the LED element 2 and the electrode 11 are connected via a protruding electrode is called a flip chip bonding type.

  In the flip chip bonding type light emitting device 100, an underfill material (not shown) may be filled in the gap between the LED element 2 and the substrate 1. The underfill material can be a member made of silicone resin, epoxy resin, or the like.

2-3. Wavelength Conversion Layer The wavelength conversion layer 3 is a layer that converts light having a specific wavelength emitted from the LED element 2 into light having another specific wavelength, and includes at least phosphor particles and plate-like swelling particles. The wavelength conversion layer 3 may be formed so as to be in contact with the LED element 2 as described above, or may be formed with a gap from the LED element 2. As shown in FIG. 1, the wavelength conversion layer 3 may be a layer that covers not only the LED element 2 and the electrode 11 but also the substrate 1 on the side where the LED element 2 is disposed. In the present invention, since metal ions, decomposition products, and the like are difficult to be derived from the interlayer cations of the plate-like swollen particles, even if the wavelength conversion layer 2 is in contact with the electrode 11 or the like, current leakage hardly occurs in the light emitting device.

  In addition, the wavelength conversion layer 3 may include a binder for binding the phosphor particles and the plate-like swelling particles as necessary. The plate-like swollen particles contained in the wavelength conversion layer 3 are the same as the plate-like swollen particles contained in the aforementioned high specific gravity particle dispersion solution.

  On the other hand, the phosphor particles contained in the wavelength conversion layer 3 may be anything that is excited by light emitted from the LED element 2 and emits fluorescence having a wavelength different from that of the light emitted from the LED element 2. For example, examples of phosphor particles that emit yellow fluorescence include YAG (yttrium, aluminum, garnet) phosphors. The YAG phosphor receives blue light (wavelength 420 nm to 485 nm) emitted from the blue LED element, and emits yellow fluorescence (wavelength 550 nm to 650 nm).

  The phosphor particles are, for example, 1) A suitable amount of flux (fluoride such as ammonium fluoride) is mixed with a mixed raw material having a predetermined composition and pressed to form a molded body. 2) The obtained molded body is packed in a crucible and fired in air at a temperature range of 1350 to 1450 ° C. for 2 to 5 hours to obtain a sintered body.

  A mixed raw material having a predetermined composition is obtained by sufficiently mixing stoichiometric ratios of oxides such as Y, Gd, Ce, Sm, Al, La, and Ga, or compounds that easily become oxides at high temperatures. It is done. Moreover, the mixed raw material which has a predetermined composition mixes the solution which dissolved 1) the rare earth elements of Y, Gd, Ce, and Sm in the acid in stoichiometric ratio, and oxalic acid, and obtains a coprecipitation oxide. 2) It can also be obtained by mixing this coprecipitated oxide with aluminum oxide or gallium oxide.

  The type of the phosphor is not limited to the YAG phosphor, and may be another phosphor such as a non-garnet phosphor that does not contain Ce.

  The average particle diameter of the phosphor particles is preferably 1 μm to 50 μm, and more preferably 10 μm or less. The larger the particle size of the phosphor particles, the higher the light emission efficiency (wavelength conversion efficiency). On the other hand, when the particle diameter of the phosphor particles is too large, a gap generated between the phosphor particles becomes large. Thereby, the intensity | strength of the wavelength conversion layer 3 tends to fall. The average particle diameter of the phosphor particles refers to the value of D50 (median diameter) measured with a laser diffraction particle size distribution meter. Examples of the laser diffraction particle size distribution measuring device include a laser diffraction particle size distribution measuring device manufactured by Shimadzu Corporation. The amount of the phosphor particles contained in the wavelength conversion layer 3 is usually 5 to 15% by mass with respect to the total mass of the wavelength conversion layer 3.

  The binder that can be included in the wavelength conversion layer 3 can be a transparent resin made of a transparent resin such as an epoxy resin or a silicone resin, or a cured product such as a known alkoxysilane monomer or oligomer thereof.

  As shown in FIG. 2, the counter substrate 4 in the case where the wavelength conversion layer 3 is laminated with the counter substrate 4 is not particularly limited as long as it is a transparent substrate with respect to visible light. It can be a transparent substrate made of resin. The thickness of the substrate is usually 700 to 2000 μm, preferably 800 to 1200 μm. In the aspect in which the counter substrate 4 and the wavelength conversion layer 3 are laminated, the wavelength conversion layer 3 may contain the binder from the viewpoint of binding the phosphor particles and the plate-like swelling particles to the counter substrate 4. preferable. In FIG. 2, the wavelength conversion layer 3 is formed on the LED element 2 side from the counter substrate 4. However, the wavelength conversion layer 3 is laminated so that the counter substrate 4 is on the LED element side from the wavelength conversion layer 3. May be.

  Here, in any embodiment, the thickness of the wavelength conversion layer 3 is not less than 100 μm and not more than 3000 μm, preferably not less than 200 μm and not more than 2800 μm, and more preferably not less than 500 μm and not more than 2500 μm. When the thickness of the wavelength conversion layer 3 is 100 μm or more, light from the light emitting element 2 can be sufficiently converted.

  The method for forming the wavelength conversion layer 3 is not particularly limited, and is appropriately selected according to the components included in the wavelength conversion layer 3, the member forming the wavelength conversion layer 3, and the like. Although the example of the formation method of the wavelength conversion layer 3 is shown below, it is not limited to this.

  The above-mentioned solution for dispersing high specific gravity particles and phosphor particles are prepared, and these are mixed at a desired ratio. The phosphor can be dispersed by a known dispersing device or stirring device such as a stirring mill, a blade kneading stirring device, a thin-film swirl type dispersing device, a high-pressure impact dispersion device, a rotation and revolution mixer, or the like. Then, the obtained phosphor dispersion liquid is applied onto the LED element 2 or the counter substrate 4 by a dispenser, a spray device, an ink jet device or the like. Thereafter, the solvent contained in the phosphor dispersion liquid is dried.

  Further, after drying the solvent, a binder for binding phosphor particles and the precursor thereof may be applied and cured as necessary. Specifically, by applying a binder forming composition containing a binder component and a solvent on a layer containing phosphor and plate-like swollen particles and curing the composition, the phosphor particles and plate-like swollen particles are cured. Etc. can be bound. The binder component may be the aforementioned silicone resin or epoxy resin, or a precursor thereof, a known alkoxysilane monomer or an oligomer thereof. The alkoxysilane monomer or oligomer is not particularly limited as long as it is hydrolyzed and polycondensed to form polysiloxane.

  The solvent contained in the binder-forming composition is appropriately selected according to the type of the binder component, for example, hydrocarbons such as toluene and xylene; ketones such as acetone and methyl ethyl ketone; ethers such as diethyl ether and tetrahydrofuran , Esters such as propylene glycol monomethyl ether acetate and ethyl acetate; monohydric alcohols; dihydric or higher polyhydric alcohols; ester solvents and the like.

  The method for applying the binder-forming composition is appropriately selected depending on the type of the binder component and the like, and can be applied using, for example, a dispenser, a spray device, an inkjet device, or the like. Moreover, the composition for binder formation is hardened as needed after application | coating of the composition for binder formation. The curing method and curing conditions of the binder forming composition are appropriately selected depending on the type of resin. An example of the curing method is heat curing.

  In addition, it is also possible to mix the phosphor dispersion liquid and the binder forming composition, and apply these mixtures on the LED element 2 or the counter substrate 4 to form the wavelength conversion layer. .

2-4. Application of Light-Emitting Device The above-described light-emitting device may be provided with other optical components (such as a lens) to form various optical members. In the light emitting device of the present invention, it is difficult for the wavelength conversion layer to undergo discoloration and the like, and further, current leakage from the plate-like swollen particles contained in the wavelength conversion layer hardly occurs. Therefore, it can be used for a long period of time and is very useful as various lighting devices.

  Hereinafter, the present invention will be described in more detail with reference to examples. However, the scope of the present invention is not limited by this.

[Method for preparing plate-like swollen particles]
(Preparation of plate-like swollen particles 1)
1 g of smectite (manufactured by Kunimine, smecton SA) and 9 g of a 1 mol / L aqueous ammonium chloride solution were mixed, and the mixture was shaken for 30 minutes with a shaker. Subsequently, the resultant was treated with a centrifugal separator at 5000 rpm for 10 minutes, and the resulting supernatant was removed. Next, the mixture of 9 g of 1 mol / L ammonium chloride aqueous solution, shaking for 30 minutes with a shaker, treatment for 10 minutes at 5000 rpm with a centrifuge, and removal of the supernatant was repeated 4 times to obtain a gel. It was.
Thereafter, 10 g of water was added to the gel. The gel was washed by repeating the operations of shaking for 30 minutes with a shaker, treatment for 10 minutes at 5000 rpm with a centrifuge, and removing the supernatant three times. The gel was vacuum-dried to obtain a smectite powder whose interlayer cations were ammonium ions.

(Preparation of plate-like swollen particles 2)
1 g of smectite (manufactured by Kunimine, smecton SA) and 9 g of a 1 mol / L aqueous solution of methylammonium chloride were mixed, and the mixture was shaken for 30 minutes with a shaker. Then, it processed at 5000 rpm for 10 minutes with the centrifuge, and produced | generated supernatant was removed. Next, the operations of mixing 9 g of 1 mol / L methylammonium chloride, shaking for 30 minutes with a shaker, treating at 5000 rpm for 10 minutes with a centrifuge, and removing the supernatant were repeated three times. Thereafter, the solid content after the solid-liquid separation was washed with water to sufficiently remove the by-product electrolyte. And the smectite powder whose interlayer is a methylammonium ion was obtained by vacuum-drying.

(Preparation of plate-like swelling particles 3 to 16 and 18 to 20)
The methylammonium chloride was prepared in the same manner as the plate-like swollen particles 2 except that the salt of various ammonium ions was changed and the interlayer cation of smectite was changed to ammonium ions shown in Tables 1 and 2. The alkylammonium ion is represented by the following general formula (1), and Tables 1 and 2 show R _{1 to} R ₄ of the ammonium ion.

(Preparation of plate-like swollen particles 17)
The smectite was changed to mica (manufactured by Corp Chemical Co., Micromica MK-100DS), and methylammonium chloride was further changed to (NH ₂ (CH ₃ ) ((CH ₂ CH ₂ CH ₂ O) ₃ H))) ⁺ · Cl ^It was prepared in the same manner as the plate-like swollen particles 2 except that it was changed to-.

[Preparation method of inorganic oxide particles]
(Preparation of inorganic oxide particles 1)
As a silica powder, AEROSIL (registered trademark) 50 (manufactured by Nippon Aerosil Co., Ltd.), which is hydrophilic silica, was used as a raw material. 100 parts by mass of this silica powder was put in a reaction vessel, and the powder was made into a fluid state by stirring under a nitrogen atmosphere. Then, 5 parts by mass of hexamethyldisilazane and water were sprayed, and heat-treated at 200 ° C. for 30 minutes to prepare methylated SiO ₂ particles.

(Preparation of inorganic oxide particles 3 to 7)
Hexamethyldisilazane is mixed with hexapentyldisilazane (inorganic oxide particle 3), hexadecyl disilazane (inorganic oxide particle 4), hexaicosyl disilazane (inorganic oxide particle 5), hexapentatetracontyl disilazane ( The inorganic silica particles 6) and hexapropyldisilazane (inorganic oxide particles 7) were modified in the same manner as the inorganic oxide particles 1 except that the surface of the hydrophilic silica was modified. Oxide particles were obtained.
The inorganic oxide particles 2 were made of AEROSIL (registered trademark) 50 (manufactured by Nippon Aerosil Co., Ltd.) of hydrophilic silica without modifying the surface with an alkyl group.

[Example 1]
20% by mass of isopropyl alcohol (hereinafter also referred to as “IPA”) and 80% by mass of 1,3-butanediol (hereinafter also referred to as “BD”) were mixed to prepare a mixed solvent. Next, the plate-like swollen particles 1 and the inorganic oxide particles 1 were added to the mixed solvent so that the amount relative to the total amount of the high specific gravity particle dispersion solution was 2% by mass. These were then dispersed with a homogenizer (manufactured by Eiko Seiki Co., Ltd.) for 10 minutes to prepare the high specific gravity particle dispersion solution of Example 1.

[Examples 2 to 43 and Comparative Examples 1 to 5]
A high specific gravity particle dispersion solution was prepared in the same manner as in Example 1 except that the amounts and types of the solvent, plate-like swollen particles, and inorganic oxide particles were changed as shown in Tables 1 and 2.

[Evaluation]
50 parts by mass of the high specific gravity particles shown in Table 1 and Table 2 are added to 100 parts by mass of the solutions for dispersing high specific gravity particles prepared in Examples 1 to 43 and Comparative Examples 1 to 5, and a homogenizer (Eihiro Seiki Co., Ltd.). For 10 minutes. High specific gravity particles are YAG phosphor (yttrium / aluminum / garnet phosphor, specific gravity: 4.5), TiO ₂ particles (specific gravity 4.5), copper particles (Mitsui Metals Co., Ltd., product number: 1400 YM, particle size: 4.2 μm, specific gravity 5.5), or aluminum oxide particles (manufactured by Mitomo Chemical Co., Ltd .: product number A-11, particle size: 40 μm specific gravity 3.1). Using a high specific gravity particle-containing liquid in which high specific gravity particles are dispersed in a high specific gravity particle dispersion solution, heat resistance and current leakage were evaluated by the following methods. Moreover, sedimentation resistance was evaluated by the following method. The results are shown in Tables 1 and 2.

(Evaluation of heat resistance (discoloration))
The heat resistance was evaluated from the transmittance after the heating test of the high specific gravity particle-containing liquid. Specifically, the evaluation was performed as follows.
The high specific gravity particle-containing liquid immediately after dispersing the high specific gravity particles was spray-coated on a glass substrate so that the thickness after drying was 1 μm and dried. Thereafter, methyl silicone (OE-6270 HF, manufactured by Toray Dow Corning Co., Ltd.) was squeegee coated so that the thickness after curing was 20 μm, and baked at 150 ° C. for 2 hours to be cured. The transmittance (A) of the obtained film was measured with a spectrophotometer (Hitachi U4100). Further, the film was heated at 150 ° C. for 2 hours, and the transmittance (B) of the heated film was measured with a spectrophotometer (Hitachi U4100). Then, the ratio ((B / A) × 100) of the transmittance (A) before the heating test and the transmittance (B) after the heating test was calculated and evaluated in five stages as follows.
5: B / A is 98% or more 4: B / A is 95% or more and less than 98% 3: B / A is 92% or more and less than 95% 2: B / A is 90% or more and 92% 1: B / A is less than 90%

(Evaluation of current leakage)
The current leakage was evaluated from the surface resistance value of the obtained film. Specifically, the evaluation was performed as follows.
50 parts by mass of a high specific gravity particle-containing liquid in which high specific gravity particles are dispersed and 50 parts by mass of methyl silicone (manufactured by Toray Dow Corning: OE-6270 HF) are mixed, squeegee-coated on a glass substrate, and 150 ° C. And baked for 2 hours to cure. Thereafter, the obtained film was stored in a constant temperature and humidity chamber at high humidity (150 ° C., 85% Rh) for 2 weeks.

Using a resistivity meter (Hiresta UP MCP-HT450, manufactured by Mitsubishi Analitech Co., Ltd.), the surface resistance value (A) of the film before storage under high humidity and the surface resistance value (B) after storage under high humidity The ratio of reduction in the surface resistance value from the initial stage was evaluated according to the following criteria using these ratios (B / A).
5: B / A is 90% or more 4: B / A is 80% or more and less than 90% 3: B / A is 70% or more and less than 80% 2: B / A is 60% or more and 70% 1: B / A is less than 60%

(Evaluation of sedimentation resistance)
For each high specific gravity particle dispersion solution, the stability when high specific gravity particles were dispersed was evaluated as follows.
First, 5 g of phosphor particles having a particle size of 30 μm are added to 10 g of the high specific gravity particle dispersion solution prepared in Examples and Comparative Examples, and dispersed for 10 minutes with a homogenizer (manufactured by Eihiro Seiki Co., Ltd.) to produce a phosphor dispersion. did.
The obtained phosphor dispersion liquid was put into a cylindrical glass bottle having a diameter of 2 cm and a volume of 5 mL, and the thickness of the supernatant when allowed to stand at 25 ° C. for 24 hours was measured and evaluated according to the following criteria.
5: No supernatant is produced 4: The thickness of the supernatant is 1 mm or less 3: The thickness of the supernatant is 1 mm or more and less than 3 mm 2: The thickness of the supernatant is 3 mm or more and less than 5 mm 1: The thickness of the supernatant is 5 mm or more

  As shown in Table 1 and Table 2 above, the interlayer cation of the plate-like swollen particles contained in the high specific gravity particle dispersion solution is an ammonium ion, and the total number of carbon atoms contained in the interlayer cation is 45. In the following cases (Examples 1 to 43), discoloration and current leakage hardly occurred in the obtained films. Further, when the high specific gravity particles (phosphor particles) were dispersed, the high specific gravity particles (phosphor particles) were difficult to settle. However, when the amount of the plate-like swollen particles exceeded 20% by mass with respect to the total amount of the solution for dispersing high specific gravity particles, current leakage was slightly likely to occur or discoloration was likely to occur (Example 39). When the total number of carbon atoms contained in the interlayer cation is 45 or less, the interlayer cation is hardly thermally decomposed and the like, and it is difficult to generate free ions. However, when the amount of the plate-like swelling particles is excessive, The amount is slightly increased, and it is assumed that discoloration and current leakage tend to occur.

  In addition, when the solvent contained a divalent or higher alcohol, precipitation resistance was likely to be good (for example, Examples 1 to 40, 42, and 43). On the other hand, when only a monohydric alcohol was contained in the solvent, the sedimentation resistance was slightly lowered (Example 41). When divalent alcohol is contained in the solvent, it is presumed that the viscosity of the solution for dispersing high specific gravity particles is likely to increase, and the high specific gravity particles are difficult to settle.

On the other hand, when the interlayer cation of the plate-like swollen particles was sodium ion (Comparative Examples 3 and 4), although it was difficult to cause discoloration in the obtained film, current leakage was likely to occur. It is inferred that one of the factors is that the interlayer cations migrated and the metal was easily deposited.
Moreover, even if the interlayer cation of the plate-like swollen particles is an ammonium ion, when the total number of carbon atoms contained in the interlayer cation exceeds 45 (Comparative Examples 1 and 2), the obtained film Discoloration was likely to occur, and current leakage was also likely to occur. When the number of carbon atoms contained in the interlayer cation increases, it is assumed that the interlayer cation is likely to be deteriorated by heat, and the decomposition product causes discoloration. In addition, it is assumed that the component generated by the degradation of the interlayer cation becomes a carrier and the current leaks.

  When the interlayer cation is not included in the plate-like swollen particles (Comparative Example 5), discoloration and current leakage are unlikely to occur in the resulting film, but the viscosity of the high specific gravity particle dispersion solution does not increase sufficiently. Sedimentation of high specific gravity particles (phosphor particles) was likely to occur.

[Example 44]
(Mounting LED elements)
One blue LED element (rectangular shape: 200 μm × 300 μm × 100 μm) was mounted in the center of the accommodating portion of the circular package (opening diameter 3 mm, bottom diameter 2 mm, wall surface angle 60 °). As shown in FIG. 1, an electrode 11 is formed on the circular package, and the electrode 11 and the blue LED element 2 are wire-bonded.

(Formation of wavelength conversion layer)
A solution for dispersing high specific gravity particles having the same composition as in Example 1 was prepared, and YAG phosphor (yttrium / aluminum / garnet phosphor, specific gravity: 4. 5) was added in an amount of 50 parts by mass, and dispersed with a homogenizer (manufactured by Eihiro Seiki Co., Ltd.) for 10 minutes. The obtained phosphor dispersion liquid was spray-coated on the aforementioned LED element. At this time, the spray pressure was 0.2 MPa, and the relative movement speed between the spray nozzle and the LED element was 55 mm / s. Thereafter, the coating film of the phosphor dispersion liquid was dried at 150 ° C. for 15 minutes.

(Application of binder forming composition)
1 g of polysiloxane oligomer dispersion (polysiloxane oligomer (organopolysiloxane) 14 mass%, isopropyl alcohol 86 mass%; KBM13, manufactured by Shin-Etsu Chemical Co., Ltd.) and 0.3 g of isopropyl alcohol are mixed to form a binder. It was set as the composition. The binder-forming composition was spray-coated on the phosphor dispersion liquid coating, and heated and fired at 150 ° C. for 1 hour. The spray pressure was 0.05 MPa, and the relative movement speed between the spray nozzle and the LED element was 150 mm / s. By this process, a wavelength conversion layer having a thickness of 35 μm was obtained.

[Examples 45 to 83 and Comparative Examples 6 to 10]
An LED device was produced in the same manner as in Example 44 except that the solution for dispersing high specific gravity particles was changed to the compositions shown in Tables 3 and 4.

[Evaluation]
With respect to the obtained LED device, the total luminous flux was measured and evaluated by the following method. When the phosphor-containing layer is discolored or current leakage occurs in the LED device, the total luminous flux decreases. Therefore, these can be evaluated by measuring the total luminous flux. The results are shown in Tables 3 and 4 below.

(Total luminous flux evaluation method)
A current of 20 mA was passed through the LED device immediately after fabrication, and the initial total luminous flux value (A) was measured. The total luminous flux measurement was performed with a spectral radiance meter CS-1000A manufactured by Konica Minolta Sensing. Thereafter, the LED device was allowed to stand in an environment of 150 ° C. for 2 hours, and the total luminous flux value (B) after the heat treatment was measured in the same manner. Then, the ratio ((B / A) × 100) with the initial total luminous flux was calculated and evaluated in five stages as follows.
5: B / A is 95% or more 4: B / A is 90% or more and less than 95% 3: B / A is 80% or more and less than 90% 2: B / A is 70% or more and 80% 1: B / A is less than 70%

  As shown in Table 3 and Table 4 above, the interlayer cation of the plate-like swelling particles contained in the wavelength conversion layer is an ammonium ion, and the total number of carbon atoms contained in the interlayer cation is 45 or less. In the case (Examples 44 to 83), it was difficult to reduce the total luminous flux. However, when the amount of the plate-like swollen particles exceeded 20% by mass with respect to the total amount of the high specific gravity particle dispersion solution, the total luminous flux tended to decrease (Example 81).

  On the other hand, when the interlayer cation of the plate-like swollen particles is a sodium ion (Comparative Examples 8 and 9), the total luminous flux is likely to decrease. It is inferred that one of the factors is that the interlayer cations migrated and the metal was easily deposited.

  Further, even if the interlayer cation of the plate-like swollen particles is an ammonium ion, when the total number of carbon atoms contained in the interlayer cation exceeds 45 (Comparative Examples 6 and 7), the total luminous flux decreases. It was written. When the number of carbon atoms contained in the interlayer cation increases, it is assumed that the interlayer cation is easily deteriorated by heat, and the decomposition product causes discoloration. In addition, it is assumed that the component generated by the deterioration of the interlayer cation becomes a carrier and current leaks.

  When the plate-like swollen particles did not contain interlayer cations (Comparative Example 10), sedimentation occurred in the phosphor dispersion liquid, and it was difficult to form a wavelength conversion layer containing phosphor particles uniformly.

  The high specific gravity particle dispersion solution of the present invention is unlikely to cause discoloration in the resulting film, and current leakage is unlikely to occur in an apparatus including the film. Further, when the high specific gravity particles are dispersed, the sedimentation of the high specific gravity particles is small and stable. Therefore, it is very useful as various inks, a dispersion for forming a phosphor layer, and a solution for preparing a slurry.

1 substrate 2 light emitting element (LED element)
3 wavelength conversion layer 4 counter substrate 11 electrode 12 metal wire 100 light emitting device

Claims (15)

Including plate-like swollen particles and a solvent,
A solution for dispersing high specific gravity particles, wherein the interlayer cation of the plate-like swollen particles is an ammonium ion represented by the following general formula (1).

(R _{1 to} R ₄ in the general formula (1) are each independently a hydrogen atom, an alkyl group having 1 to 45 carbon atoms, a poly (oxyalkylene) -containing group having 1 to 45 carbon atoms, A hydroxy group-containing alkyl group having 1 to 45 carbon atoms,
(The total number of carbon atoms contained in R _{1 to} R ₄ is 0 or more and 45 or less) The solution for dispersing high specific gravity particles according to claim 1, wherein the total number of carbon atoms contained in R _{1 to} R ₄ in the general formula (1) is 0 or more and 30 or less. The solution for dispersing high specific gravity particles according to claim 1 or 2, wherein R _{1 to} R ₄ in the general formula (1) are all hydrogen atoms.   The amount of the plate-like swollen particles with respect to the total amount of the solution for dispersing high specific gravity particles is 0.5% by mass or more and 20% by mass or less, according to any one of claims 1 to 3. solution.   The solution for dispersing high specific gravity particles according to any one of claims 1 to 4, further comprising inorganic oxide particles.   The solution for dispersing high specific gravity particles according to claim 5, wherein the amount of the inorganic oxide particles is 0.5% by mass or more and 20% by mass or less with respect to the total amount of the solution for dispersing high specific gravity particles.   The solution for dispersing high specific gravity particles according to claim 5 or 6, wherein the inorganic oxide particles are surface-modified with a hydrocarbon group having 1 to 45 carbon atoms.   The solution for dispersing high specific gravity particles according to any one of claims 1 to 7, wherein the solvent contains a polyhydric alcohol.   A phosphor dispersion liquid comprising phosphor particles and a solution for dispersing high specific gravity particles according to any one of claims 1 to 8. A manufacturing method of a light emitting device comprising a substrate, a light emitting element disposed on the substrate, and a wavelength conversion layer covering the light emitting element,
The manufacturing method of a light-emitting device including the process of apply | coating the fluorescent substance dispersion liquid of Claim 9. A light emitting device comprising: a substrate; a light emitting element disposed on the substrate; and a wavelength conversion layer covering the light emitting element,
The wavelength conversion layer includes phosphor particles and plate-like swelling particles,
The light emitting device, wherein the interlayer cation of the plate-like swelling particles is an ammonium ion represented by the following general formula (1).

(R _{1 to} R ₄ in the general formula (1) are each independently a hydrogen atom, an alkyl group having 1 to 45 carbon atoms, a poly (oxyalkylene) -containing group having 1 to 45 carbon atoms, A hydroxy group-containing alkyl group having 1 to 45 carbon atoms,
(The total number of carbon atoms contained in R _{1 to} R ₄ is 0 or more and 45 or less) The light emitting device according to claim 11, wherein the total number of carbon atoms contained in R _{1 to} R ₄ in the general formula (1) is 0 or more and 30 or less. The light emitting device according to claim 11 or 12, wherein all of R _{1 to} R ₄ in the general formula (1) are hydrogen atoms.   The light emitting device according to claim 11, wherein the wavelength conversion layer further includes inorganic oxide particles.   The light emitting device according to claim 14, wherein the inorganic oxide particles are surface-modified with a hydrocarbon group having 1 to 45 carbon atoms.

Images