JPH11181419A - Production of metal oxide-based fluophor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing the subject fluophor of small grain size through baking at relatively low temperatures. SOLUTION: This method for producing a metal oxide-based fluophor comprises forming a complex polymer by polymerization reaction of a metal complex with a polyol in a solvent followed by baking the complex polymer, wherein the metal complex has been previously prepared by reaction of an oxycarboxylic acid or a polyaminochelating agent with at least one kind of compound selected from the group constituting the fluophor base and activator which consist of carbonates, nitrates, hydroxides, sulfates, phosphates, borates, silicates, aluminates, carboxylates, halides, and alkoxides of metallic elements.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a metal oxide-based phosphor, and more particularly, to a method for producing a metal oxide-based phosphor having an extremely small particle diameter by a complex polymerization method.

[0002]

2. Description of the Related Art Conventionally, a metal oxide-based fluorescent phosphor is prepared by mixing an oxide containing a metal element constituting the phosphor as a raw material, mixing the mixture, and firing the mixture at a high temperature of 1200 ° C. or higher to obtain a solid-state phosphor. It is common to produce a phosphor by reacting. However, this method required firing for a long time. In addition, in the conventional production method based on the reaction between solids, the particle size of the phosphor becomes large, and it is necessary to further perform classification or the like in order to obtain a small particle size.
Adjustment of particle size was also difficult. In addition, there is a disadvantage that a metal oxide-based phosphor having a uniform composition cannot be obtained because unreacted raw materials remain.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and to provide a method for producing a metal oxide phosphor having a small particle size by firing at a relatively low temperature. .

[0004]

The present invention has succeeded in solving the above-mentioned problems by adopting the following constitution. (1) Carbonates, hydroxides, nitrates, sulfates, phosphates, borates, and metal elements constituting the base material and activator of the phosphor,
A metal complex obtained by reacting at least one compound selected from silicates, aluminates, carboxylates, halides, and alkoxides with an oxycarboxylic acid or a polyamino chelating agent, in a solvent And producing a complex polymer by a polymerization reaction with a polyol, and calcining the complex polymer.

(2) The method for producing a metal oxide-based phosphor according to the above (1), wherein the metal element constituting the activator is a rare earth element. (3) The rare earth elements constituting the activator are europium (Eu), terbium (Tb), praseodymium (P
r), at least one rare earth element selected from cerium (Ce) samarium (Sm) and dysprosium (Dy). .

(4) The metal element constituting the base is at least one element selected from yttrium (Y), gadolinium (Gd) and lanthanum (La), and the activator is Any one of the above (1) to (3), wherein the constituent rare earth element is at least one rare earth element selected from europium (Eu), cerium (Ce) and terbium (Tb). 5. A method for producing a metal oxide-based phosphor according to any one of the above.

(5) The oxycarboxylic acid is citric acid,
Tartaric acid, malic acid, tartronic acid, hydroacrylic acid,
The method for producing a metal oxide-based phosphor according to any one of the above (1) to (4), which is at least one oxycarboxylic acid selected from lactic acid and glycolic acid. (6) The method for producing a metal oxide-based phosphor according to the above (5), wherein the oxycarboxylic acid is citric acid.

(7) The polyamino chelating agent is ethylenediaminetetraacetic acid, trans-1,2-cyclohexanediaminetetraacetic acid, triethylenetetramineminhexaacetic acid, nitrilotriacetic acid, tetraethylenepentamineheptaacetic acid, N- (2-hydroxy Ethyl) -ethylenediamine-N, N ', N'-triacetic acid, 1 selected from diethylenetriamine and triethylenetetramine
The method for producing a metal oxide-based phosphor according to any one of the above (1) to (6), which is at least one kind of polyamino chelating agent.

(8) The polyol is ethylene glycol, propylene glycol, trimethylene glycol,
Any one of the above (1) to (7), which is at least one polyol selected from 1,4-butadiol, 1,5-pentadiol and 1,6-hexanediol. A method for producing the metal oxide-based phosphor according to the above. (9) The method for producing a metal oxide-based phosphor according to (8), wherein the polyol is ethylene glycol.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention provides a metal complex obtained by reacting a specific compound of a metal element constituting a base of a phosphor and an activator with an oxycarboxylic acid or a polyamino chelating agent, The metal complex undergoes a polymerization reaction with a polyol in a solvent to form a complex polymer, which is fired to lower the firing temperature. As a result, a metal oxide-based fluorescent material having a desired small particle size can be obtained. Enabled the manufacture of the body.

[0011] The specific compound of the metal element constituting the base material and the activator of the phosphor used in the present invention is carbonate, hydroxide, nitrate, sulfate, phosphate, borate of the metal element. , Silicates, aluminates, carboxylates, halides and alkoxides. Among them, nitrates, acetates and carboxylates are particularly preferred. As the solvent used in the production method of the present invention, various liquids can be used, and among them, water or alcohol is preferable.

The oxycarboxylic acid used in the present invention includes, for example, citric acid, tartaric acid, malic acid, tartronic acid, hydroacrylic acid, lactic acid, glycolic acid and the like. Among them, citric acid is particularly preferred. .

The polyamino chelating agent used in the present invention includes, for example, ethylenediaminetetraacetic acid, trans-1,2-cyclohexanediaminetetraacetic acid, triethylenetetramineminhexaacetic acid, nitrilotriacetic acid,
Tetraethylenepentamine heptaacetic acid, N- (2-hydroxyethyl) -ethylenediamine-N, N ', N'-triacetic acid, diethylenetriamine, triethylenetetramine and the like are used.

In the present invention, the obtained metal complex is polymerized with glycol to obtain a metal complex polymer. As the glycol used here, for example, ethylene glycol, propylene glycol, trimethylene glycol, 1,4
-Butadiol, 1,5-pentadiol, 1,6-hexanediol, etc., among which ethylene glycol is particularly preferred.

The amount of glycol used is 2 to 200 times, preferably 10 to 30 times, the total number of moles of the metal elements constituting the matrix and the activator of the oxide phosphor. It is. If the amount of the glycol used is less than 2 moles, the polymerization reaction is unlikely to occur, and there is a possibility that the metal complex polymer will not be formed. This is not preferable because the manufacturing cost of the phosphor increases.

The polymerization of the metal complex is carried out by adding glycol to the solution of the metal complex and heating the mixture. This heat treatment is preferably carried out in two stages. First, heat the solvent in the first stage,
Remove. The temperature at this time is suitably in the range of 40 to 190 ° C, preferably 110 to 140 ° C. If the solvent removal temperature is lower than 40 ° C., it takes a long time to remove the solvent, which is not preferable. If it is higher than 190 ° C., the glycol may evaporate quickly and a desired complex may not be formed.

In the second heat treatment, polymerization proceeds by an esterification reaction between the metal complex and glycol. The polymerization temperature at this time is 100 to 300 ° C., preferably 140 ° C.
A range of -190 ° C is appropriate. When the polymerization temperature is 10
If it is lower than 0 ° C., the esterification reaction may not proceed, and if it is higher than 300 ° C., the esterification reaction may locally proceed and become non-uniform.

The thus obtained metal complex polymer is then thermally decomposed to obtain an oxide phosphor powder. The thermal decomposition temperature at this time depends on the type of the oxide phosphor, but is 25%.
A range of 0 to 1200 ° C, preferably 500 to 900 ° C is appropriate. When the thermal decomposition temperature is lower than 250 ° C., there is a possibility that the thermal decomposition of the complex polymer does not occur.
When the temperature is higher than 00 ° C., there is a possibility that the grain growth may abnormally proceed or the constituents may evaporate and the single phase may not be formed.

At this time, the heating atmosphere for the thermal decomposition is not necessarily required to be in the air, but may be performed in a neutral atmosphere or a reducing atmosphere as necessary. The phosphor obtained in this way has excellent crystallinity, high purity and fine particle diameter of 1 μm or less, because the metal elements constituting the matrix and the activator are uniformly mixed. You can get the body.

The oxide-based phosphor produced by the method of the present invention includes (Sr, Ca) B, an ultraviolet-emitting phosphor.
₄ O ₇ : Eu, blue light-emitting phosphor Y ₂ SiO ₅ : Ce,
Ca ₂ B ₅ O ₉ Cl: Eu, BaMgAl ₁₄ O ₂₃ : E
u, BaO · 6Al ₂ O ₃ : Mn, Y of green light emitting phosphor
_{3 Al 5 O 12: Ce,} Y 3 Al 5 O 12: Tb, ZnSi
O ₄ : Mn, InBO ₃ : Tb, LnPO ₄ : Ce, T
b, of the red-emitting phosphor _{Y 2 O 3: Eu, YVO} 4: E
u, MgSiO ₃ : Mn, Zn ₃ (PO ₄ ) ₂ : Mn,
InBO ₄ : Eu, (Y, Gd) BO ₃ : Eu, SrT
iO ₃ : Pr, K ₂ La ₂ Ti ₈ O _{10 and the} like. Among them, a phosphor activated by one kind selected from Eu, Ce and Tb, for example, Y emitting red light emission
_{2 O 3: Eu, (Y} , Gd) BO 3: Eu or the like, BaMgAl ₁₄ O ₂₃ emits blue light _{emission: Eu, Y 3 Al 5 O} 12 exhibited green light _{emission: Ce, Y 3 Al 5 O} 12: Tb , etc. In particular, when producing an oxide phosphor of the above, it is possible to obtain a small-diameter phosphor having a particularly high luminance.

[0021]

(Example 1) Ethylene glycol (EG) and citric acid (CA) were added to a beaker with EG: CA = 40: 1.
The mixture was weighed to a molar ratio of 0, kept at about 40 ° C. on a hot stirrer, and stirred until the CA was completely dissolved. Next, yttrium nitrate hexahydrate and europium nitrate hexahydrate were added to this solution, and EG: CA: Y: Eu = 4.
0: 10: 1: 0.04 molar ratio was added sequentially, and the mixture was stirred at about 40 ° C. until completely dissolved to obtain a colorless and transparent solution. This solution was heated and stirred at about 130 ° C. on a hot stirrer to allow the polymerization reaction to proceed. As the polymerization reaction proceeded, the viscosity of the solution increased, and after several hours, a brown resinous solid (a complex polymer of yttrium (Y) containing europium (Eu)) was formed.

Next, this brown resinous solid was heated at 350 ° C. for several hours using a mantle heater, and pulverized while removing the solvent, excess organic matter and the solvent, to obtain a black powdery solid. Put this black powdery solid in an alumina boat and heat treated for 2 hours at 600 ° C. using an electric furnace Y ₂ O
₃ : Eu phosphor was obtained. The emission color (C) of the obtained Y ₂ O ₃ : Eu phosphor when irradiated with ultraviolet light of 254 nm.
The emission chromaticity point (expressed in the IE color system), the emission luminance, and the particle size of the phosphor were measured, and the results are shown in Table 1. The emission luminance was shown as a relative value with respect to the phosphor obtained in the following comparative example.

[0023] except that the (Example 2) Europium was obtained in the same manner as in Example 1 (Eu) containing yttrium (Y) complex polymer was heated for 2 hours at 700 ° C., in the same manner as in Example 1 Y ₂ O ₃ : Eu phosphor was obtained. The emission color (emission chromaticity point represented by the CIE color system) and emission luminance when the obtained phosphor was irradiated with ultraviolet light of 254 nm and the particle size of the phosphor were measured, and the results are shown in Table 1.

[0024] except that 2 hours of heat treatment in (Embodiment 3) 900 ° C. The obtained was europium (Eu) containing yttrium (Y) complex polymer as in Example 1, in the same manner as in Example 1 Y ₂ O ₃ : Eu phosphor was obtained. The emission color (emission chromaticity point represented by the CIE color system) and emission luminance when the obtained phosphor was irradiated with ultraviolet light of 254 nm and the particle size of the phosphor were measured, and the results are shown in Table 1.

(Comparative Example) The metal element in the raw material mixture was used.
In order to have the same stoichiometric composition as in Example 1, Y _TwoO_ThreePassing
And Eu_TwoO_ThreeWeigh the oxide powder of
Addition and mixing of lithium as flux and alumina crucible
And heat-treated at 1400 ° C for 4 hours in air
By Y_TwoO_Three: Eu phosphor was obtained. Obtained phosphor
In the same manner as in Example 1 under the excitation of ultraviolet light of 254 nm.
Relative emission luminance and emission color (emission color expressed in CIE color system)
And the particle size of the phosphor was measured and the results are shown in Table 1.
did.

[0026]

[Table 1]

(Evaluation) As is clear from Table 1, the phosphors of Examples 1 to 3 are ultrafine particles each having a particle size of 100 nm or less obtained by conversion from the measured value of the specific surface area by the BET method. Compared with the phosphor of the comparative example obtained by a solid-to-solid reaction at a high temperature of 1400 ° C. or higher using a flux, the emission chromaticity point is close and the color tone of the emission color hardly changes, and the emission luminance at a practical level Was shown.

[0028]

According to the present invention, the sintering temperature of the metal oxide-based phosphor can be reduced to 1200 ° C. or less by employing the above-mentioned structure, and the metal oxide-based phosphor in the form of ultra-fine particles of 1 μm or less can be obtained. You can now gain body.

Claims (7)

[Claims] 1. A carbonate, a nitrate, a hydroxide, a sulfate, a phosphate of a metal element constituting a base material and an activator of a phosphor,
Metal complex obtained by reacting at least one compound selected from borate, silicate, aluminate, carboxylate, halide and alkoxide with oxycarboxylic acid or polyamino chelating agent Is reacted with a polyol in a solvent to form a complex polymer, and the complex polymer is calcined to produce a complex polymer. 2. The method according to claim 1, wherein the metal element forming the activator is a rare earth element. 3. The rare earth element constituting the activator is selected from europium (Eu), terbium (Tb), praseodymium (Pr), cerium (Ce), samarium (Sm), and dysprosium (Dy). 3. The method according to claim 2, wherein the phosphor is at least one rare earth element. 4. The method according to claim 1, wherein the metal elements constituting the base are yttrium (Y), gadolinium (Gd), and lanthanum (L).
a) at least one element selected from the group consisting of europium (E)
u), cerium (Ce) and terbium (Tb) are at least one rare earth element selected from the group consisting of: a metal oxide phosphor according to any one of claims 1 to 3; Production method. 5. The method according to claim 1, wherein the oxycarboxylic acid is at least one selected from citric acid, tartaric acid, malic acid, tartronic acid, hydroacrylic acid, lactic acid and glycolic acid. A method for producing a metal oxide-based phosphor according to any one of claims 1 to 4. 6. The polyamino chelating agent may be ethylenediaminetetraacetic acid, trans-1,2-cyclohexanediaminetetraacetic acid, triethylenetetramineminhexaacetic acid, nitrilotriacetic acid, tetraethylenepentamineheptaacetic acid, N- (2-hydroxyethyl 6.) One or more polyamino chelating agents selected from the group consisting of:)-ethylenediamine-N, N ', N'-triacetic acid, diethylenetriamine and triethylenetetramine. A method for producing the metal oxide-based phosphor according to the above. 7. The method according to claim 1, wherein the polyol is ethylene glycol, propylene glycol, trimethylene glycol,
The metal according to any one of claims 1 to 6, wherein the metal is one or more polyols selected from 1,4-butadiol, 1,5-pentadiol, and 1,6-hexanediol. A method for producing an oxide phosphor.