JP2013213096A - Coated sulfide-based green phosphor particle and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sulfide-based green phosphor which can suppress deterioration caused by an influence such as contact with the other material and a water component, and the generation of a gas, and its manufacturing method.SOLUTION: In a coated sulfide-based green phosphor particle, a layer having polysiloxane coupling is coated on a sulfide-based green phosphor particle which is expressed by a prescribed composition formula. The coated sulfide-based green phosphor particle is characterized by being obtained in such a manner that first alkoxide being polyalkoxysilane, alkoxide including second alkoxide, and a coating liquid containing an organic compound having two or more hydroxyl groups are mixed with the sulfide-based green phosphor particle, and heat-treated.

Description

  The present invention relates to a sulfide-based green phosphor having a coating layer and a method for producing the same, and more particularly to a coated sulfide-based green phosphor excellent in moisture resistance or water resistance and a method for producing the same.

  In the field of electronic devices, various functional particles are used for the purpose of imparting thermal conductivity, electrical conductivity, magnetism, fluorescence characteristics, and the like. However, functional particles deteriorate by reacting with materials and moisture that come into contact with the particles, and gas is generated, resulting in adverse effects such as a decrease in the function of the electronic device. There's a problem. In other words, there are many materials that are difficult to use even though they have excellent functionality at the beginning of use, which deteriorates with time.

  In order to solve such problems, attempts have been made to coat the surface of the particles with a barrier layer to suppress the deterioration of the particles or to reduce the adverse effects of the gas from the particles on the electronic device. For example, in Patent Documents 1 to 5, surface treatment using a metal alkoxide is performed on phosphor particles (Patent Document 1), a silicone resin (Patent Document 2), or a glass layer containing silicon and oxygen on the surface of the phosphor particles. (Patent Documents 3 and 5), a silicon oxide film (Patent Document 4), and the like are formed.

JP 2007-91874 A JP 2005-187797 A JP 2007-308537 A JP 2006-188700 A JP 2011-26535 A

  However, in the above-described conventional technology, heat treatment under a high temperature of 200 ° C. or higher and high pressure conditions is necessary for forming the barrier layer, and functional particles such as phosphor particles themselves are formed by heat treatment under such conditions. There is a problem that the barrier function (that is, the function of suppressing particle deterioration and gas generation) is not sufficiently exhibited due to deterioration or cracks in the barrier layer.

  Therefore, the present invention pays particular attention to sulfide-based green phosphors as functional particles, and sulfide-based green phosphors capable of suppressing deterioration and gas generation due to contact with other materials and the influence of moisture and the like and their production It aims to provide a method.

The present invention that has achieved the above object is represented by (i) a composition formula: (M ¹ _1-x Eu _x ) Ga ₂ S ₄ , and M ¹ in the composition formula is selected from the group consisting of Ba, Sr, and Ca. Or at least one of the sulfide-based green phosphor particles in which x is 0.001 to 0.1, or (ii) represented by the composition formula: (M ² _1-y Eu _y ) ₂ SiS ₄ , A coating in which M ² is at least one selected from the group consisting of Ba, Sr, and Ca, and y is 0.001 to 0.1, and a layer having a polysiloxane bond is coated on a sulfide-based green phosphor particle A sulfide-based green phosphor particle comprising a coating liquid containing a first alkoxide, which is a polyalkoxysilane, an alkoxide containing a second alkoxide, and an organic compound having two or more hydroxyl groups. Mixed with physical green phosphor particles, Is a coating sulfide-based green phosphor particles characterized by being obtained by treating.

The present invention also includes a method for producing the above-described coated sulfide-based green phosphor particles, that is, (i) represented by the composition formula: (M ¹ _1-x Eu _x ) Ga ₂ S ₄ , M ^{1 in the} formula is at least one selected from the group consisting of Ba, Sr, and Ca, x is a sulfide-based green phosphor particle in which 0.001 to 0.1, or (ii) Composition formula: (M ² _{1 -y} Eu _y ) ₂ SiS ₄ , M ² in the composition formula is at least one selected from the group consisting of Ba, Sr and Ca, and y is 0.001 to 0.1 sulfide-based green fluorescence A method for producing a coated sulfide-based green phosphor particle in which a body particle is coated with a layer having a polysiloxane bond, the first alkoxide being a polyalkoxysilane, and an alkoxide containing a second alkoxide; An organic compound having two or more hydroxyl groups Including a coating liquid, mixed with sulfide-based green phosphor particles, a method for producing a coated sulfide-based green phosphor particles, characterized by heat treatment with.

  In any of the coated sulfide-based green phosphor particles and the method for producing the same of the present invention, it is preferable that the organic compound, alkoxide, and sulfide-based green phosphor particles satisfy the following requirements. The organic compound preferably contains polyvinyl alcohol, and preferably contains one or more selected from ethylene glycol, propylene glycol, and glycerin, or the amount of the organic compound is 100 parts by mass of the alkoxide. It is also preferable that it is 2.0-20 mass parts. The first and second alkoxides are preferably two kinds selected from ethyl tetrasilicate, methyl trisilicate ethyl, and phenyl trisilicate ethyl.

  The average particle diameter of the sulfide-based green phosphor particles is preferably 0.1 to 50 μm.

  Moreover, in the manufacturing method of this invention, it is preferable that the temperature of the said heat processing is less than 200 degreeC.

  The present invention also includes a white LED and a light-emitting device having the coated sulfide-based green phosphor particles obtained by the above production method.

  According to the present invention, it has a polysiloxane bond obtained by heat-treating a coating solution containing a first alkoxide that is a polyalkoxysilane, a second alkoxide, and an organic compound having two or more hydroxyl groups. Since the layer is covered with sulfide-based green phosphor particles, sulfide-based green phosphor particles having excellent water resistance or moisture resistance can be realized. In a preferred embodiment of the present invention, since the heat treatment temperature when forming the layer covering the sulfide-based green phosphor particles is a low temperature of less than 200 ° C., the deterioration of the sulfide-based green phosphor particles is suppressed. Thus, sulfide-based green phosphor particles having excellent barrier properties can be realized by a simpler method.

Fig.1 (a) is a graph showing the UV-VIS spectrum in the Example mentioned later, FIG.1 (b) is an enlarged view of Fig.1 (a).

  The coated sulfide-based green phosphor particles of the present invention are sulfide-based green phosphor particles coated with a layer having a polysiloxane bond (hereinafter referred to as “coating layer”), and the coating layer is a polyalkoxy compound. It is characterized in that it is obtained by heat-treating a coating liquid containing a first alkoxide that is silane, a second alkoxide, and an organic compound having two or more hydroxyl groups. The coated sulfide-based green phosphor particles thus obtained are excellent in water resistance or moisture resistance.

  The coating layer is, for example, a silica layer. The coating layer is preferably amorphous, and particularly preferably an amorphous silica layer. Whether or not the coating layer is formed and whether or not the coating layer is amorphous can be confirmed by a surface analysis method such as X-ray photoelectron spectroscopy (XPS) or X-ray diffraction (XRD).

  The coating layer is formed by a step of preparing a coating solution and a coating treatment step of coating the coating solution on sulfide-based green phosphor particles.

1. Coating liquid preparation process An alkoxide and an organic compound having two or more hydroxyl groups (hereinafter simply referred to as “organic compound”) are stirred and mixed in the presence of an acid catalyst to cause a hydrolysis reaction. A coating solution in which the compound is complexed can be obtained. In this step, the compounding of the alkoxide and the organic compound proceeds to some extent, so that the heat treatment temperature in the subsequent coating treatment step can be set to less than 200 ° C., and deterioration of the sulfide-based green phosphor particles due to heat can be suppressed.

  In this step, the temperature can be set to, for example, 20 to 80 ° C. (preferably 25 to 70 ° C.), and the stirring and mixing time can be set to, for example, 0.5 to 48 hours (preferably 30 minutes to 5 hours).

The alkoxide includes first and second alkoxides, and the first alkoxide is a polyalkoxysilane. Polyalkoxysilane forms a polysiloxane bond by hydrolysis and dehydration condensation reactions. The polyalkoxysilane, such as tetra silicate methyl, tetra silicate C _1-4 alkyl, such as tetra-ethyl silicate; methyltri silicate methyl (methyl trimethoxy silane), C _1-4 alkyl, such as methyl tri ethyl silicate (methyltriethoxysilane) C _1-4 alkyl trisilicate; aryl trisilicate C _1-4 alkyl such as methyl phenyl trisilicate (phenyltrimethoxysilane), ethyl phenyltrisilicate (phenyltriethoxysilane), and the like are included. The first alkoxide is preferably ethyl tetrasilicate, methyl trisilicate methyl, methyl trisilicate ethyl, phenyl trisilicate methyl or phenyl trisilicate ethyl.

As the second alkoxide, a compound other than the compound used as the first alkoxide may be selected from the compounds exemplified as the first alkoxide, or an aluminum alkoxide may be used. Examples of the aluminum alkoxide include tri-C _1-3 alkylalkoxyaluminum and compounds obtained by substituting a part of the alkoxy group of tri-C _{1-3 alkylalkoxyaluminum} with a C _1-10 alkylacetoacetate. . As the tri C _1-3 alkyl alkoxy aluminum, such as aluminum tri-isopropylate and the like, a part of the alkoxy groups of tri C _1-3 alkyl alkoxy aluminum as compounds substituted with C _1-10 alkyl acetoacetic ester , Ethyl acetoacetate aluminum diisopropylate, or octyl acetoacetate aluminum diisopropylate. Further, instead of the second alkoxide, a compound in which the alkoxy group of the aluminum alkoxide described above is completely substituted with acetylacetone may be used. However, since an alcohol is generated as a by-product after the reaction, it is preferable to use an alkoxide. .

  The alkoxide may be composed of only the first and second alkoxides, and may further include third and subsequent alkoxides. As the third and subsequent alkoxides, compounds other than the compounds used as the first and second alkoxides can be selected from the compounds exemplified as the first and second alkoxides.

  The molar ratio of the second alkoxide is preferably 0.05 to 1 and more preferably 0.2 to 0.8 with respect to the first alkoxide. When the third and subsequent alkoxides are used, the molar ratio of the third and subsequent alkoxides is preferably 0.01 to 0.5, more preferably 0.05. ~ 0.2.

  More preferably, the first and second alkoxides are two kinds selected from ethyl tetrasilicate, methyl trisilicate ethyl, and phenyl trisilicate ethyl.

  In particular, combinations of alkoxides are: (i) ethyl tetrasilicate and methyl trisilicate, (ii) ethyl tetrasilicate and phenyl trisilicate, (iii) ethyl tetrasilicate, methyl trisilicate and aluminum triisopropylate, (iv) tetra Preferred are ethyl silicate, ethyl phenyltrisilicate, and aluminum triisopropylate.

  The organic compound having two or more hydroxyl groups described above has an effect of improving the coating properties and handling properties of the coating liquid and the moisture resistance of the resulting coated sulfide-based green phosphor particles. Examples of the organic compound having two or more hydroxyl groups include polyvinyl alcohols, glycols (such as ethylene glycol and propylene glycol) and polymers thereof (such as polyethylene glycol), and triols such as glycerin, preferably polyvinyl alcohol, It is at least one selected from polyethylene glycol, ethylene glycol, propylene glycol, and glycerin. In particular, when polyvinyl alcohol is used, the number average degree of polymerization and the saponification degree may be appropriately adjusted according to the solvent used, and the number average degree of polymerization is, for example, 100 to 5000, preferably 2000 or less, more preferably 500 or less. Yes, the degree of saponification is, for example, 70 to 95 mol% (preferably 80 to 90 mol%). The saponification degree of polyvinyl alcohol means the ratio of hydroxyl groups to the total number of acetic acid groups and hydroxyl groups in polyvinyl alcohol.

  The amount of the organic compound (the total amount when two or more types are used) is 100 parts by mass of the total amount of the alkoxide, that is, the first and second alkoxides and the third and subsequent alkoxides used as necessary. On the other hand, it is preferable that it is 2.0-20 mass parts, More preferably, it is 3-10 mass parts, More preferably, it is 4-7 mass parts.

  In the case of stirring and mixing the alkoxide and the organic compound, an acid catalyst is usually used. Thereby, an alkoxide and an organic compound can be mixed uniformly, and a uniform coating layer can be formed in the subsequent coating process. As the acid catalyst, hydrochloric acid or nitric acid can be used. It is preferable that the usage-amount of an acid catalyst is 0.1-3 mass parts with respect to 100 mass parts of total amounts of an alkoxide, More preferably, it is 0.2-2 (especially 0.3-1) mass part. .

  In addition, when the organic compound is solid, the time required for compositing the alkoxide and the organic compound can be shortened by dissolving the organic compound in a solvent in advance. Examples of the solvent include ion exchange water; alcohols such as ethanol and isopropyl alcohol; aromatic hydrocarbons such as toluene and xylene; sulfur compounds such as dimethyl sulfoxide (DMSO) and sulfolane; N, N-dimethylformamide (DMF) and N Acid amides such as N, dimethylacetamide are preferably used, and dimethyl sulfoxide and ethanol are preferred. The usage-amount of a solvent is about 10-1000 mass parts (preferably 20-700 mass parts, More preferably, 30-500 mass parts) with respect to 100 mass parts of total amounts of an alkoxide.

2. Coating processing step After mixing the coating solution containing the alkoxide and organic compound obtained in the coating solution preparation step described above with sulfide-based green phosphor particles (nuclei), and using a solvent, after removing the solvent Then, heat treatment is performed.

  The mixing method of the coating liquid and the sulfide-based green phosphor particles (core) may be any method as long as the coating liquid can uniformly coat the surface of each sulfide-based green phosphor particle. A method of dispersing, a method of spraying the coating liquid into the fluidized particles, and the like can be employed. The mixing method may be either dry mixing or wet mixing, and a stirring mixing device, an ultrasonic vibration mixing device, or the like can be used. Specific examples of the mixing apparatus include a Henschel mixer manufactured by Mitsui Miike Manufacturing Co., Ltd., a super mixer manufactured by Kawata Corporation, and the like. The mixing temperature is, for example, 20 to 80 ° C. (preferably 20 to 60 ° C.), and the mixing time is 0.1 to 24 hours (preferably 0.1 to 3 hours).

The mixing ratio of the coating liquid and the sulfide-based green phosphor particles (nuclei) varies depending on the mixing method, but the amount of the coating liquid is 1 to 20000 parts by mass (preferably 100 parts by mass of the sulfide-based green phosphor particles). Is preferably 20 to 1000 parts by mass, more preferably 40 to 500 parts by mass. By setting it as such a mixing ratio, the quantity of a coating layer can be 0.1-50 mass parts (preferably 0.2-20 mass parts) with respect to 100 mass parts of sulfide type green fluorescent substance particles. . In addition, the content of Si in the coating layer is preferably 0.1 to 20 parts by mass, more preferably 0.5 to 100 parts by mass in terms of SiO _{2 with} respect to 100 parts by mass of the sulfide-based green phosphor particles (nuclei). It is 10 mass parts, More preferably, it is 1.0-5.0 mass parts.

  As a method for removing the solvent, techniques such as vacuum filtration, vacuum drying, and blast drying can be used. The temperature of vacuum drying and ventilation drying is 50-150 degreeC (preferably 60-120 degreeC), for example, and time is 0.1 to 24 hours (preferably 0.5 to 6 hours), for example.

  In the case where the alkoxide and the organic compound are completely complexed by performing a heat treatment, a coating layer is formed on the surface of the sulfide-based green phosphor particles (nuclei), and the solvent remains. The solvent can be completely removed. The heat processing temperature is 120 degreeC or more and less than 200 degreeC, for example, Preferably it is 120-180 degreeC. The heat treatment time is, for example, 1 to 48 hours, and preferably 1 to 24 hours. If the treatment temperature is too low or the treatment time is too short, the barrier property of the coating layer becomes insufficient, and the moisture resistance or water resistance cannot be improved. Further, if the heat treatment temperature is 200 ° C. or higher, the sulfide-based green phosphor particles themselves deteriorate, which is not preferable.

  The atmosphere during the heat treatment is not particularly limited, and may be any of an inert gas atmosphere, an oxidizing gas atmosphere, and a reducing gas atmosphere. The inert gas is, for example, nitrogen or argon. Examples of the oxidizing gas include air, oxygen, and a mixed gas of an inert gas (such as nitrogen and argon) and oxygen. The reducing gas includes a mixed gas of inert gas (nitrogen, argon, etc.) and 0.1 to 10% by volume of hydrogen, ammonia, and the like.

The sulfide-based green phosphor particles usable in the present invention are represented by (i) composition formula: (M ¹ _1-x Eu _x ) Ga ₂ S ₄ , and M ¹ in the composition formula is Ba, Sr and At least one selected from the group consisting of Ca, x is 0.001 to 0.1 sulfide-based green phosphor particles, or (ii) composition formula: (M ² _1-y Eu _y ) ₂ SiS ₄ M ² in the composition formula is at least one selected from the group consisting of Ba, Sr, and Ca, and sulfide-based green phosphor particles in which y is 0.001 to 0.1.
The composition formula (M ¹ _1-x Eu _x ) Ga ₂ S ₄ can also be expressed as M ¹ Ga ₂ S ₄ : Eu ²⁺ , where M ¹ Ga ₂ S ₄ means the composition of the host crystal, It means a luminescent ion in which Eu ²⁺ is activated. The compositional formula: (M ² _1-y Eu _y ) ₂ SiS ₄ can also be expressed as M ² ₂ SiS ₄ : Eu ²⁺ , where M ² ₂ SiS ₄ means the composition of the parent crystal, It means a luminescent ion in which Eu ²⁺ is activated. Both M ¹ and M ² are preferably Sr and / or Ca, or Sr and / or Ba, and more preferably only Sr. Moreover, as for x and y, 0.01-0.05 are preferable. The green phosphor refers to a phosphor having a light emission peak at a wavelength of about 510 to 550 nm.

The sulfide-based green phosphor represented by the above composition formula can be obtained by mixing raw materials containing elements constituting the phosphor and firing the mixture. As a raw material, a simple substance, an oxide, a carbonate, a nitride, or a halide of each constituent element of the phosphor can be used. The usage ratio of each raw material is determined so that the composition ratio of each constituent element is the composition ratio represented by the above composition formula in the phosphor after firing. At this time, the amount ratio of the raw materials used may be a value different from the composition ratio in the composition formula in consideration of element scattering due to firing.
The mixing of each raw material can apply the method used industrially, and may be either a wet type or a dry type. Specifically, for example, a ball mill, a V-type mixer, a stirrer, a jet mill or the like can be used.
The firing atmosphere is not particularly limited and may be any of an oxidizing gas atmosphere such as air; an inert gas atmosphere such as nitrogen and argon; and a reducing gas atmosphere such as H ₂ , CO, NH ₃ , and H ₂ S. Also good. A preferable firing atmosphere is a mixed gas atmosphere of a reducing gas and an inert gas, and a mixed gas atmosphere of an inert gas and H ₂ is particularly preferable. Further, it is also preferable to perform firing in a reducing gas atmosphere at least temporarily during the firing step.
The firing temperature is, for example, 900 to 1200 ° C. (preferably 950 to 1100 ° C.), and the firing time is, for example, 1 to 100 hours (1 to 24 hours).
Moreover, you may add additives, such as a flux, in order to improve the reactivity at the time of baking of a raw material.

  As the sulfide-based green phosphor particles of the present invention, for example, the average particle diameter is 0.1 to 500 μm (the lower limit of the average particle diameter is preferably 0.5 μm or more, more preferably 1.0 μm or more, and the upper limit is Sulfide green phosphor particles of preferably 100 μm or less, more preferably 50 μm or less) can be used. Here, the average particle diameter in the present specification means a number-based median diameter (D50), and can be measured by, for example, a laser diffraction scattering method.

  The coated sulfide-based green phosphor particles of the present invention are excellent in water resistance or moisture resistance, and are exposed to a high temperature and high humidity environment (for example, 85 ° C. or higher, relative humidity of 85% or higher) for a predetermined time (for example, 500 hours or longer). Even so, it is possible to suppress the deterioration of the characteristics of the coated sulfide-based green phosphor particles. The coated sulfide-based green phosphor particles of the present invention have, for example, 95% or more (preferably 98%) of luminescence intensity after being exposed to a high-temperature and high-humidity environment relative to the luminescence intensity before being exposed to a high-temperature and high-humidity environment. % Or more, more preferably 100%).

  The present invention is industrially useful because it contributes to higher functionality and higher performance of the light emitting material.

  The present invention also includes a light-emitting device having coated sulfide-based green phosphor particles. More specifically, a light emitting device including an excitation source (particularly an LED) and a phosphor part, and the phosphor part is the coated sulfide-based green phosphor particle; an LED excitation source and a phosphor part, and a phosphor part The white LED etc. which are the said covering sulfide type green fluorescent substance particles are mentioned. A white LED is taken as an example of the light emitting device and will be described below.

  The white LED can be manufactured by a method disclosed in, for example, Japanese Patent Application Laid-Open Nos. 11-31845 and 2002-226846. That is, a light emitting element that emits light having a wavelength of 200 nm or more and 500 nm or less is sealed with a light-transmitting resin such as an epoxy resin or a silicone resin, and a phosphor is disposed so as to cover the surface of the white LED, Can be manufactured. What is necessary is just to set the quantity of fluorescent substance suitably so that white LED can light-emit desired white.

In the phosphor portion of the white LED, the coated sulfide-based green phosphor particles of the present invention may be used alone or in combination with other phosphors. Other phosphors include BaMgAl ₁₀ O ₁₇ : Eu, (Ba, Sr, Ca) (Al, Ga) ₂ S ₄ : Eu, BaMgAl ₁₀ O ₁₇ : (Eu, Mn), BaAl ₁₂ O ₁₉ : (Eu , Mn), (Ba, Sr, Ca) S: (Eu, Mn), YBO ₃ : (Ce, Tb), Y ₂ O ₃ : Eu, Y ₂ O ₂ S: Eu, YVO ₄ : Eu, (Ca Sr) S: Eu, SrY ₂ O ₄ : Eu, Ca—Al—Si—O—N: Eu, (Ba, Sr, Ca) Si ₂ O ₂ N ₂ : Eu, β-sialon, CaSc ₂ O ₄ : Ce, Li- (Ca, Mg) -Ln-Al-O-N: Eu (wherein Ln represents a rare earth metal element other than Eu), (Ba, Sr, Ca) .2SiO ₄ : Eu ²⁺ , (Ba, Sr, Ca) .3SiO ₅ : Eu ²⁺ , YAG and the like. The elements in parentheses can be changed at an arbitrary ratio.

Examples of light emitting elements that emit light having a wavelength of 200 nm to 500 nm include ultraviolet LEDs, blue LEDs, and the like, and these include GaN, In _i Ga _1-i N (0 <i <1), In _i Al as a light emitting layer. _{j Ga 1-ij N (0} <i <1,0 <j <1, i + j <1) is a semiconductor having a layer of such used. The emission wavelength can be changed by changing the composition of the light emitting layer.

  The coated sulfide-based green phosphor particles obtained by the production method of the present invention include, in addition to a white LED, a light emitting device (for example, PDP) whose phosphor excitation source is vacuum ultraviolet light; and light emission whose phosphor excitation source is ultraviolet light Devices (for example, backlights for liquid crystal displays, three-wavelength fluorescent lamps); light emitting devices (for example, CRT and FED) in which the phosphor excitation source is an electron beam can also be used.

  Hereinafter, the present invention will be described more specifically with reference to examples. The present invention is not limited by the following examples, and can of course be implemented with appropriate modifications within a range that can be adapted to the above-described gist. Included in the range.

[Coating solution adjustment]
(1) Coating liquid 1
Ethyl tetrasilicate (TEOS, Tama Chemical Co., Ltd.) 0.8 mol, methyl trisilicate ethyl (MeTEOS, Shin-Etsu Silicone) 0.2 mol, water 4.0 mol, dimethyl sulfoxide (DMSO, Wako Pure Chemical Industries) 10 mol, To a liquid in which polyvinyl alcohol (PVA, average polymerization degree 500, saponification degree 86 to 90 mol%, Wako Pure Chemical Industries, Ltd.) is mixed, 0.01 mol of nitric acid is added dropwise, and the mixture is stirred at room temperature for 60 minutes for coating liquid 1 Was prepared. The amount of PVA was 5% by mass with respect to ethyl tetrasilicate and methyl trisilicate.
(2) Coating liquid 2
Ethyl tetrasilicate (TEOS, Tama Chemical Co., Ltd.) 0.8 mol, ethyl phenyltrisilicate (PhTEOS, Shin-Etsu Silicone) 0.2 mol, water 4.0 mol, dimethyl sulfoxide (DMSO, Wako Pure Chemical Industries) 10 mol , Polyvinyl alcohol (PVA, average polymerization degree 500, saponification degree 86-90 mol%, Wako Pure Chemical Industries, Ltd.) was mixed dropwise with 0.01 mol of nitric acid, and then stirred at room temperature for 60 minutes for coating solution. 1 was prepared. The amount of PVA was 5% by mass with respect to ethyl tetrasilicate and ethyl phenyltrisilicate.
(3) Coating liquid 3
Ethyl tetrasilicate (TEOS, Tama Chemical Co., Ltd.) 0.8 mol, phenyl trisilicate ethyl (PhTEOS, Shin-Etsu Silicone) 0.2 mol, ethanol 1.6 mol, propylene glycol (PG, Wako Pure Chemical Industries) After 0.01 mol of nitric acid was added dropwise to the solution, the mixture was stirred at 70 ° C. for 60 minutes to prepare a coating solution 3. The amount of PG was 5% by mass relative to ethyl tetrasilicate and ethyl phenyltrisilicate.
(4) Coating liquid 4, 7-9
Coating liquids 4 and 7 to 9 were obtained in the same manner as the coating liquid 3 except that the alkoxides and organic compounds used were changed to the types and amounts shown in Table 1. In Table 1, AIPO means aluminum triisopropylate.
(5) Coating liquid 5, 6, 10-12
Coating liquids 5, 6, and 10 to 12 were obtained in the same manner as coating liquids 1 and 2, except that the alkoxide and organic compound used were changed to the types and amounts shown in Table 1.

  In addition, the amount of solvent in each coating liquid is adjusted so that the solid content in the coating liquids 1 to 12 is constant.

Test example 1
Reference Examples 1-23, Comparative Examples 1-3
As the phosphor particles (nuclei), the phosphors shown in Table 2 (the average particle diameter shown in Table 2 means the median diameter based on the number) are used as the coating liquids. 12 was used to coat the phosphor in the following manner. That is, 2.3 g of coating liquid, 5.0 g of phosphor, and 2.0 g of ethanol as a solvent were added and mixed for 10 minutes (temperature was room temperature), and the solvent was removed at 60 ° C. or 80 ° C. with an evaporator (for solvent removal). It took about 0.5 hours. The mixture from which the solvent had been removed was heat-treated at 120 ° C. for 10 hours in an air atmosphere to obtain a coated phosphor. At this time, the Si content in the coating layer was 3.0 parts by mass in terms of SiO _{2 with} respect to 100 parts by mass of the phosphor (nucleus). Tables 3 and 4 show phosphors and coating solutions used in the comparative examples and reference examples.

Comparative Examples 4-7
In Comparative Examples 4-7, no coating treatment was performed, and phosphor No. 1-4 itself was used. Therefore, the column of “Coating phosphor emission intensity” in Comparative Examples 4 to 7 is phosphor No. It means the emission intensity of 1 to 4 itself.

  About each reference example and comparative example, the fluorescence spectroscopy measuring apparatus about the light emission intensity | strength after the coating fluorescent substance at the time of 450 nm light irradiation, and high temperature high-humidity processing (85 degreeC and the relative humidity 85% of atmosphere hold | maintain for 500 hours) (Measured using FP-6500 manufactured by JASCO Corporation). The results are shown in Tables 3 and 4. In addition, emission intensity (1) and (2) in each test example is shown as a relative value when the emission intensity before coating treatment of each test example is set to 100, and for Comparative Examples 4 to 7, emission intensity (1 ) Means the emission intensity (that is, 100) of the phosphor itself in the comparative example.

  From Tables 3 and 4, the phosphors (Reference Examples 1 to 23) coated with a coating solution containing the first and second alkoxides and an organic compound having two or more hydroxyl groups have improved moisture resistance or water resistance. As a result, it was possible to suppress a decrease in emission intensity after the high temperature and high humidity treatment. On the other hand, an example in which only one kind of alkoxide was used and / or an organic compound having two or more hydroxyl groups (Comparative Examples 1 to 3) and an example in which no coating was performed (Comparative Examples 4 to 7) In this case, the emission intensity was remarkably lowered after the high temperature and high humidity treatment.

Test example 2
Slide glasses coated with the coating liquids 1 and 3 used in Test Example 1 were prepared, and UV-VIS spectroscopy (Ultraviolet / Visible Absorption Spectroscopy) spectra were measured. At the time of measurement, the slide glass coated with the coating solution was placed on the sample side, and the measurement was performed by placing the slide glass on the reference side with nothing or nothing applied. The measurement conditions are as follows.
Measuring device: V-560 (manufactured by JASCO)
Wavelength range: 190-900 nm
Response: Medium
Scanning speed: 1000 nm / min
Band width: 2nm
Light source: Deuterium lamp, tungsten lamp (340nm switching)

  The results are shown in FIG. FIG. 1 is a graph showing UV-VIS spectral spectra of a slide glass and a slide glass coated with coating solutions 1 and 3, respectively. According to FIG. 1, even when the coating liquids 1 and 3 are applied, the absorbance is almost the same as that of the slide glass alone. That is, it can be seen that even when the coating liquids 1 and 3 are applied to the phosphor, the light emission characteristics of the phosphor are not inhibited.

Claims (17)

Composition formula: (M ¹ _1-x Eu _x ) Ga ₂ S _4, where M ¹ is at least one selected from the group consisting of Ba, Sr and Ca, and x is 0.001 to 0.00. 1 is a coated sulfide-based green phosphor particle in which a layer having a polysiloxane bond is coated on the sulfide-based green phosphor particle which is 1.
A coating solution containing an alkoxide containing a first alkoxide, which is a polyalkoxysilane, and a second alkoxide, and an organic compound having two or more hydroxyl groups is mixed with the sulfide-based green phosphor particles, followed by heat treatment. Coated sulfide-based green phosphor particles obtained by: Composition formula: (M ² _1-y Eu _y ) ₂ SiS _4, where M ² is at least one selected from the group consisting of Ba, Sr and Ca, and y is 0.001 to 0.1. A sulfide-based green phosphor particle in which a sulfide-based green phosphor particle is coated with a layer having a polysiloxane bond,
A coating solution containing an alkoxide containing a first alkoxide, which is a polyalkoxysilane, and a second alkoxide, and an organic compound having two or more hydroxyl groups is mixed with the sulfide-based green phosphor particles, followed by heat treatment. Coated sulfide-based green phosphor particles obtained by:   The coated sulfide-based green phosphor particles according to claim 1 or 2, wherein the organic compound contains polyvinyl alcohol.   4. The coated sulfide-based green phosphor particle according to claim 1, wherein the organic compound includes one or more selected from ethylene glycol, propylene glycol, and glycerin.   The coated sulfide-based green phosphor particles according to any one of claims 1 to 4, wherein the first and second alkoxides are two kinds selected from ethyl tetrasilicate, methyl trisilicate ethyl, and phenyl trisilicate ethyl. .   6. The coated sulfide-based green phosphor particle according to claim 1, wherein the amount of the organic compound is 2.0 to 20 parts by mass with respect to 100 parts by mass of the alkoxide.   The coated sulfide-based green phosphor particles according to claim 1, wherein the sulfide-based green phosphor particles have an average particle diameter of 0.1 to 50 μm. Composition formula: (M ¹ _1-x Eu _x ) Ga ₂ S _4, where M ¹ is at least one selected from the group consisting of Ba, Sr and Ca, and x is 0.001 to 0.00. A method for producing coated sulfide-based green phosphor particles in which a sulfide-based green phosphor particle that is 1 is coated with a layer having a polysiloxane bond,
A coating liquid containing an alkoxide containing a first alkoxide, which is a polyalkoxysilane, and a second alkoxide, and an organic compound having two or more hydroxyl groups is mixed with sulfide-based green phosphor particles and heat-treated. A method for producing coated sulfide-based green phosphor particles, wherein: Composition formula: (M ² _1-y Eu _y ) ₂ SiS _4, where M ² is at least one selected from the group consisting of Ba, Sr and Ca, and y is 0.001 to 0.1. A method for producing coated sulfide-based green phosphor particles in which a sulfide-based green phosphor particle is coated with a layer having a polysiloxane bond,
A coating liquid containing an alkoxide containing a first alkoxide, which is a polyalkoxysilane, and a second alkoxide, and an organic compound having two or more hydroxyl groups is mixed with sulfide-based green phosphor particles and heat-treated. A method for producing coated sulfide-based green phosphor particles, wherein:   The manufacturing method according to claim 8 or 9, wherein the organic compound includes polyvinyl alcohol.   The said organic compound is a manufacturing method in any one of Claims 8-10 containing 1 or more types selected from ethylene glycol, propylene glycol, and glycerol.   The manufacturing method according to claim 8, wherein the first and second alkoxides are two kinds selected from ethyl tetrasilicate, methyl trisilicate ethyl, and phenyl trisilicate ethyl.   The manufacturing method according to claim 8, wherein the amount of the organic compound is 2.0 to 20 parts by mass with respect to 100 parts by mass of the alkoxide.   The production method according to any one of claims 8 to 13, wherein an average particle diameter of the sulfide-based green phosphor particles is 0.1 to 50 µm.   The temperature of the said heat processing is less than 200 degreeC, The manufacturing method in any one of Claims 8-14.   White LED which has the covering sulfide type green fluorescent substance particle obtained by the manufacturing method in any one of Claims 8-15.   The light-emitting device which has the covering sulfide type green fluorescent substance particle obtained by the manufacturing method in any one of Claims 8-15.