KR100385703B1 - New manufacturing method of preparing spherical bam blue phosphor - Google Patents

Abstract

The present invention relates to a new method for producing a spherical BAM blue phosphor, and more particularly to a method for producing BaMgAl ₁₀ O ₁₇ : Eu ²⁺ used as a blue phosphor of a plasma display panel (PDP) or a lamp.

The present invention comprises (a) under glycol a group consisting of ⅰ) [(CH ₃ ) ₂ CHO] ₃ Al, ii) BaCO ₃ , (CH ₃ CO ₂ ) ₂ Ba, and Ba (OH) ₂₈ H ₂ O. A mixture of barium compounds selected from iii) MgCO ₃ or (CH ₃ CO ₂ ) ₂ Mg ₄ H ₂ O, and iv) Eu ₂ O ₃ with a homogeneous molecular mixture of a fluorescent raw material and a melting agent Doing; (b) heat-treating the mixture in air at a temperature of 600 to 1000 ° C. to produce a mixed raw powder; And (c) heat treating the mixed raw material powder under a mixed gas atmosphere consisting of nitrogen and hydrogen in a closed reactor.

In the present invention, the fluorescent raw material can be uniformly mixed at the molecular level in the glycol solution to simplify the process and improve the yield, and a spherical blue phosphor having a uniform particle distribution of less than 5 μm of pure crystalline phase can be obtained. Implementation is possible.

Description

New manufacturing method of spherical SAM blue phosphor {NEW MANUFACTURING METHOD OF PREPARING SPHERICAL BAM BLUE PHOSPHOR}

[TECHNICAL FIELD OF THE INVENTION]

The present invention relates to a new method for producing a spherical BAM blue phosphor, and more particularly to a method for producing BaMgAl ₁₀ O ₁₇ : Eu ²⁺ used as a blue phosphor of a plasma display panel (PDP) or a lamp.

[Private Technology]

Phosphors are widely used in the display field using visible light as a substance that emits light when external energy such as radiation, electron beam, ultraviolet ray, electric field, heat, and chemical reaction is applied. In general, desirable characteristics of color display phosphors should have high luminous efficiency and good color purity of red, green, blue, and three primary colors, and their optical characteristics change due to the thermal and chemical treatments applied to the display parts. It should be possible to implement a high brightness screen with little and good applicability.

Application of the phosphor particles to the plasma display panel is generally commercially used a method of laminating the phosphor particles in a plurality of layers using a screen printing method of the paste prepared of the phosphor. At this time, the case where the compactness of the laminated phosphor particles is high is preferable to implement a high luminance screen, and the influence of the phosphor particles is greatly affected by the shape of the phosphor particles to be used by excluding the influence factors caused by the paste preparation and the coating process. In general, it is well known that the filling of phosphor particles having a spherical shape is higher than that of non-spherical phosphor particles, and therefore, it is a common desire of phosphor suppliers to shape phosphor particles.

In general, the phosphor is fired at a temperature of 600 to 1500 ° C. in which a solid chemical reaction can be performed in a batch or continuous electric furnace controlled by mixing a high-purity raw material and a crystal growth controlling flux. The size and shape of the phosphors produced are dependent on the firing time and temperature and the type and amount of the melt.

Commercially available BAM (BaMgAl ₁₀ O ₁₇ : Eu ²⁺ ) blue phosphors have an average particle diameter of 2 to 10 µm, and each particle is close to a single crystal. Recently, attention has been paid to the shape of particles and the small particle size due to the resolution as a fluorescent film and the limitation of the structure of devices.

Efforts have been reported to produce spherical particles by sol-gel hydrothermal synthesis, combustion synthesis, coprecipitation, etc. in order to produce small spherical BAM blue particles.

Although BASE blue phosphor for PDP was manufactured by KASEI and NICHIA of Japan, this blue phosphor has a plate-like structure, which is not suitable for high brightness screen.

In addition, Matsushita Co., Ltd. has developed a method for producing phosphors using spherical alumina as a starting material without using a melting agent (US Pat. No. 5,897,586), but the surface of the prepared phosphors grows in a plate shape and has high brightness. Not suitable for the screen implementation of.

In addition, a method of manufacturing a BAM blue phosphor using a pyrolysis method (J. Aerosol. Sci. 28, PS 541, 1997) was developed, but this method also has a problem in that the surface has a plate-like shape, which causes poor filling properties when laminated. have.

In order to solve the above problems, the present invention provides a method for producing a BAM blue phosphor, which simplifies the process, improves the yield, and has a spherical shape of individual particles and a spherical shape of less than 5 μm, which is desirable for high brightness screen. It aims to provide.

It is another object of the present invention to provide a spherical BAM blue phosphor prepared by the above method.

1 is an SEM photograph (× 5000) of the phosphor prepared in Example 1,

2 is an SEM photograph (× 4000) of the phosphor prepared by Comparative Example 1,

3 is an SEM photograph (× 4000) of the phosphor prepared by Comparative Example 2,

4 is a SEM photograph (× 5000) of a BAM blue phosphor manufactured by KASEI.

The present invention to achieve the above object,

(a) under glycol

Iii) [(CH ₃ ) ₂ CHO] ₃ Al,

Ii) a barium compound selected from the group consisting of BaCO ₃ , (CH ₃ CO ₂ ) ₂ Ba, and Ba (OH) ₂₈ H ₂ O,

Iii) MgCO ₃ or (CH ₃ CO ₂ ) ₂ Mg ₄ H ₂ O, and

Iii) Eu ₂ O ₃

Preparing a mixture by uniformly mixing the fluorescent raw material and the melting agent at a molecular level comprising a;

(b) heat-treating the mixture in air at a temperature of 600 to 1000 ° C. to produce a mixed raw powder; And

(c) heat treating the mixed raw material powder under a mixed gas atmosphere composed of nitrogen and hydrogen in a closed reactor;

It provides a method for producing a spherical blue phosphor comprising a.

The present invention also provides a spherical blue phosphor prepared by the above described method.

Hereinafter, the present invention will be described in detail.

The present inventors heat-treated BAM glycolate prepared after homogeneous mixing of fluorescent raw materials using glycol at 1000 ° C. or lower to prepare BAM phosphor raw materials, and then put them in a closed reactor to heat-treat under a mixed gas atmosphere composed of nitrogen and hydrogen. Then, the present invention was completed by discovering that a smaller spherical blue phosphor was formed than the phosphor prepared by the conventional method.

The present invention comprises the steps of preparing a mixture, preferably BAM glycolate by mixing the fluorescent raw material and the melting agent by a uniform mixing method using glycol.

The fluorescent raw material used in the present invention is a barium compound selected from the group consisting of [(CH ₃ ) ₂ CHO] ₃ Al, BaCO ₃ , (CH ₃ CO ₂ ) ₂ Ba, and Ba (OH) ₂₈ H ₂ O. And MgCO ₃ or (CH ₃ CO ₂ ) ₂ Mg ₄ H ₂ O and Eu ₂ O ₃ . Preferably, the mixing ratio of the raw materials is a barium compound selected from the group consisting of [(CH ₃ ) ₂ CHO] ₃ Al: BaCO ₃ , (CH ₃ CO ₂ ) ₂ Ba, and Ba (OH) ₂₈ H ₂ O: It is preferable that the molar ratio of MgCO ₃ or (CH ₃ CO ₂ ) ₂ Mg ₄ H ₂ O: Eu ₂ O ₃ is 2: 0.36: 0.4: 0.04.

The homogeneous mixing method using a thin group glycol is a barium compound selected from the group consisting of BaCO ₃ , (CH ₃ CO ₂ ) ₂ Ba, and Ba (OH) ₂₈ H ₂ O, MgCO ₃ or (CH ₃ CO ₂ ) ₂ Mg ₄ After dissolving H ₂ O and Eu ₂ O ₃ in HNO ₃ , the mixture was mixed with [(CH ₃ ) ₂ CHO] ₃ Al in a glycol solution and reacted at 200 ° C. or lower, whereby Ba, Mg, Eu, and Al reacted with glycol. Reaction produces a well mixed BAM glycolate at the molecular level. At this time, HNO ₃ , water, and substances generated during the reaction can be easily removed due to the difference in the break point with the glycol. The glycol is preferably selected from ethylene glycol (C ₂ H ₆ O ₂ ) or 1,4-butanediol (C ₄ H ₁₀ O ₂ ), but the glycol used in the present invention is not limited thereto.

In the present invention, the melting agent may be used either in the homogeneous mixing with the raw material in the preparation of the mixture (BAM glycolate) or after mixing the mixture to prepare a mixture. The present invention includes both the method of mixing by performing the ball milling (ball milling) in the method of mixing the fluorescent raw material and the melting agent or in the production of BAM glycolate.

The shape controlling flux used in the present invention is preferably a compound containing fluorine. More preferably, the compound containing fluorine is selected from the group consisting of ZnF ₂ , MnF ₂ , BaF ₂ and mixtures thereof. The amount of the melting agent is preferably adjusted to have an appropriate size depending on the display in which the phosphor is used. That is, since the size of the phosphor required for the PDP requires a phosphor having a size of 2 to 4 μm, it is preferable to use 0.1 to 10.0% by weight.

In addition, the present invention comprises the step of producing a mixture of the raw material well mixed at the molecular level by heat-treating the mixture prepared by the above process in air at a temperature of 600 to 1000 ℃ or less.

According to the present invention, it is possible to omit several processes of raw material mixing as compared to the conventional process, and to obtain a phosphor having a pure crystal phase after firing by homogeneous mixing and a uniform particle distribution compared to the conventional process.

In addition, the present invention includes the step of heat-treating the mixed raw material powder prepared in the above process in a closed gas atmosphere consisting of nitrogen and hydrogen in a closed reactor.

The closed reactor is preferably a faced alumina crucible. When the reactor is open during heat treatment, it is preferable that the reactor is closed because a problem in that the shape of the phosphor particles produced is not uniform is generated.

The heat treatment step of the present invention is carried out under an atmosphere of a mixed gas of nitrogen and hydrogen, the mixed gas is used to reduce the trivalent Eu to divalent Eu. The mixing ratio of the mixed gas is preferably a nitrogen: hydrogen mixing ratio of 92: 8 to 98: 2 by volume. This is because if the content of hydrogen is less than 2%, the reducing power is weak and if it exceeds 10%, there is a problem in the safety of the process. More preferably, the mixing ratio of the mixed gas is 96: 4.

The heat treatment temperature in the heat treatment process of the present invention is preferably 1,100 to 1,700 ℃, more preferably 1,300 to 1,500 ℃. At this time, if the heat treatment temperature is less than 1,100 ℃ BAM phosphor is not formed well, or the size of the formed particles is too small problem, if the heat treatment temperature exceeds 1,700 BAM phosphor is well formed but the size of the formed particles Not good because it gets too big

In addition, the present invention provides a spherical blue phosphor produced by the method for producing a spherical blue phosphor, the phosphor is characterized by a spherical phosphor of less than 5 ㎛ size average particle size smaller than the spherical phosphor by the conventional method. The spherical blue phosphor manufactured according to the present invention is particularly preferably used for plasma display panels requiring high brightness screens.

As described above, the method for preparing the phosphor of the present invention is a homogeneous mixing method using glycol, which simplifies the production process of the BAM blue phosphor and increases the yield. The crystal phase is pureer than the conventionally manufactured phosphor, and the particle distribution is uniform. Spherical phosphors having a particle diameter of less than 5 μm can be produced.

Hereinafter, Examples and Comparative Examples of the present invention will be described. However, the following examples are intended to illustrate the invention and the present invention is not limited to the following examples.

Example 1

0.18 mol of Ba (OH) ₂₈ H ₂ O, 0.2 mol of (CH ₃ CO ₂ ) ₂ Mg ₄ H ₂ O, and 0.01 mol of Eu ₂ O ₃ completely dissolved in 300 ml of 63% HNO ₃ , followed by 1 liter of ethylene glycol The solution was mixed with 2 mol of [(CH ₃ ) ₂ CHO] ₃ Al and reacted at 200 ° C. or lower to prepare BAM glycolate, and then heat-treated in air at a temperature of 600 ° C. to prepare BAM raw materials. The mixture was prepared by ball milling 99.7% by weight of the BAM raw material and 0.3% by weight of the AlF ₃ melter at 250 rpm for 20 hours using ethanol as a solvent. The mixture was encapsulated in a 300 cc faced crucible and sealed and heat-treated at 1,500 ° C. for 4 hours under an atmosphere of a mixed gas consisting of 96% by volume of N ₂ and 4% by volume of H ₂ to prepare a phosphor. The shape of the prepared phosphor is shown in Figure 1 by SEM (Scanning Electron Microscope). In FIG. 1, it was confirmed that the shape of the phosphor particles was less than 5 μm, and the particles were formed evenly.

Comparative Example 1

99.7% by weight of a fluorescent raw material consisting of 4 mol of Al (OH) ₃ , 0.36 mol of BaCO ₃ , 0.4 mol of MgO, and 0.04 mol of Eu ₂ O ₃ and 0.3 wt% of AlF ₃ by using ethanol as a solvent for 20 hours The mixture was prepared by ball milling and drying. The mixture was sealed in a 300 cc surface-treated crucible and heat-treated at 1,400 ° C. for 2 hours under an atmosphere of a mixed gas consisting of 96% by volume of N ₂ and 4% by volume of H ₂ to prepare a phosphor. The shape of the prepared phosphor was shown in Figure 2 by scanning electron microscope (SEM). In Figure 2 it can be seen that the shape of the phosphor particles are larger than Example 1.

Comparative Example 2

29.9 mol of Al ₂ O ₃ , 0.36 mol of BaCO ₃ , 0.4 mol of MgO, 0.04 mol of Eu ₂ O ₃ and 0.1 wt% of AlF ₃ melter were used for 20 hours at 250 rpm using ethanol as a solvent. The mixture was milled and then dried. The mixture was placed in a 300 cc faced crucible and the lid was slightly opened and heat treated at 1,500 ° C. for 4 hours in an atmosphere of a mixed gas consisting of 96% by volume of N ₂ and 4% by volume of H ₂ to prepare a phosphor. The shape of the prepared phosphor is shown in FIG. 3. It can be seen that the shape of the phosphor is elongated in FIG. 3.

In addition, when the SEM picture (× 5000) of the BAM blue phosphor manufactured by KASEI, conventionally, it can be seen that the shape of the phosphor is elongated.

As described above, in the present invention, the fluorescent raw material may be uniformly mixed at the molecular level in the glycol solution to simplify the process and improve the yield, and the spherical blue phosphor having a uniform particle distribution of less than 5 μm of pure crystal phase High brightness screen can be realized.

Claims (12)

(a) under glycol Iii) [(CH ₃ ) ₂ CHO] ₃ Al, Ii) a barium compound selected from the group consisting of BaCO ₃ , (CH ₃ CO ₂ ) ₂ Ba, and Ba (OH) ₂₈ H ₂ O, Iii) MgCO ₃ or (CH ₃ CO ₂ ) ₂ Mg ₄ H ₂ O, and Iii) Eu ₂ O ₃ Preparing a mixture by uniformly mixing the fluorescent raw material and the melting agent at a molecular level comprising a; (b) heat-treating the mixture in air at a temperature of 600 to 1000 ° C. to produce a mixed raw powder; And (c) heat treating the mixed raw material powder under a mixed gas atmosphere composed of nitrogen and hydrogen in a closed reactor; Method of producing a spherical blue phosphor comprising a. The method for producing a spherical blue phosphor according to claim 1, wherein the glycol of (a) is selected from ethylene glycol and 1,4-butanediol. The method of claim 1, wherein the homogeneous mixing of the fluorescent raw material and the melting agent of (a) is a homogeneous mixing of the raw material in the preparation of the mixture, or to prepare a spherical blue phosphor to be mixed after preparing the mixture. Way. The method for producing a spherical blue phosphor according to claim 1, wherein the melting agent of (a) is a compound containing fluorine. The method of producing a spherical blue phosphor according to claim 4, wherein the melter is selected from the group consisting of AlF ₃ , MgF ₂ , BaF ₂ and mixtures thereof. The method for producing a spherical blue phosphor according to claim 1, wherein the amount of the melting agent of (a) is 0.1 to 10.0 wt%. The method of manufacturing a spherical blue phosphor according to claim 1, wherein the heat treatment temperature of (c) is 1,100 to 1,300 ° C. The method of manufacturing a spherical blue phosphor according to claim 1, wherein a mixing ratio of nitrogen gas: hydrogen gas in the mixed gas of (c) is 96% by volume: 4% by volume. The method of manufacturing a spherical blue phosphor according to claim 1, wherein the blue phosphor is for a plasma display panel. A spherical blue phosphor prepared by the method described in claim 1. The spherical blue phosphor according to claim 10, wherein the blue phosphor is for a plasma display panel. The spherical blue phosphor according to claim 10, wherein the spherical blue phosphor has a spherical particle shape, and the spherical blue phosphor particles have a size of less than 5 µm.