KR20100068345A - Powdery fluorine-containing magnesium oxide and process for preparing same - Google Patents

Abstract

PURPOSE: A magnesium oxide powder containing fluorine is provided to emit UV ray a high efficiency in case of being excited by UV ray. CONSTITUTION: A method for a magnesium oxide powder containing fluorine comprises: a step of inputting mixture powder of magnesium oxide ingredient powder and fluorine source powder and a step of plasticizing the mixture powder. The powder containing fluorine is magnesium fluoride powder. The purity of the magnesium oxide ingredient powder is more than 99.95 mass%.

Description

Fluorine-containing magnesium oxide powder and its manufacturing method {POWDERY FLUORINE-CONTAINING MAGNESIUM OXIDE AND PROCESS FOR PREPARING SAME}

[Brief Description of Drawings]

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows the relationship between the fluorine content and the ultraviolet light emission intensity | strength of the baked material (fluorine-containing magnesium oxide powder) manufactured in Example 1. FIG.

[Documentation of the prior art]

[Patent Document 1] Japanese Unexamined Patent Publication No. 2004-288508

[Patent Document 2] Japanese Unexamined Patent Publication No. 2004-296273

[Non-Patent Document 1] Ei Otani, and 6 others, "PDP that achieved 2.21m / W light emission efficiency, high-quality full HD panel," Nikkei Electronics, Nikkei BP Co., Ltd., 2005 March 26, p.129-138

The present invention relates to magnesium oxide powder containing fluorine.

An AC plasma display panel (hereinafter also referred to as an AC PDP) generally includes a front plate serving as an image display surface, and a rear plate disposed opposite to each other with a discharge space filled with discharge gas. The front plate consists of a front glass substrate, a pair of discharge electrodes formed on the front glass, a dielectric layer formed to cover the discharge electrodes, and a dielectric protective layer formed on the surface of the dielectric layer. The back plate consists of a back glass substrate, an address electrode formed on the glass substrate, a partition wall for partitioning the discharge space formed to cover the glass substrate and the address electrode, and a red, green, and blue phosphor layer formed on the surface of the partition wall. .

Generally as a discharge gas, mixed gas of Xe (xenon) and Ne (neon) is used. In this mixed gas, Xe is a discharge gas and Ne is a buffer gas.

As a material for forming the dielectric protective layer, magnesium oxide having a high secondary electron emission coefficient and excellent sputter resistance is widely used to reduce the operating voltage of the AC-type PDP and to protect the dielectric layer from plasma generated in the discharge space. It is becoming.

Conventionally, for the purpose of improving the discharge characteristics and the light emission characteristics of the AC PDP, forming another layer on the discharge space side surface of the derivative protective layer has been studied.

Patent Document 1 uses a material having a higher secondary electron emission coefficient and lower work function than the dielectric protective layer (MgO) on the discharge space side surface of the dielectric protective layer for the purpose of further reducing the operating voltage of the AC type PDP. It has been proposed to form a secondary electron emission layer (high? Material layer) formed by the above method, and the discharge start voltage of the address discharge is lowered by the secondary electrons emitted from the high? Material layer, so that the address discharge is discharged at a low voltage and at a high speed. It is described that it can be performed. In addition, Patent Document 1 discloses an oxide of an alkali metal (for example, Cs ₂ O), an oxide of an alkaline earth metal (for example, CaO, SrO, BaO), and a fluoride as a material for forming a high? Material layer. For example, a material in which the secondary electron emission coefficient is increased by introducing CaF ₂ , MgF ₂ ), crystal defects or impurities in the crystals (for example, Mg: O, such as Mg0x, changes the composition ratio of Mg: O from 1: 1 to introduce crystal defects). One), TiO ₂ and Y ₂ O ₃ are contained.

Patent Literature 2 discloses an ultraviolet light (vacuum ultraviolet light) generated by the gas discharge of Xe gas on the surface of the discharge space side of the derivative protective layer to emit ultraviolet light for the purpose of improving the light emission characteristics of the AC PDP. It is proposed to form an external light emitting layer (second phosphor layer). This patent document 2 discloses a material of an ultraviolet light emitting layer as BaSi ₂ O ₅ : Pb, (Ba, Sr, Mg) ₃ Si ₂ O ₇ : Pb, (Sr, Ba) ₂ MgSi ₂ O ₇ : Pb, SrB ₄ O ₇ : Eu, SrAl ₁₂ O ₁₉ : Ce, (Gd, La) B ₃ O ₆ : Bi, (Ca, Zn) ₃ (PO ₄ ) ₂ : Tl, YPO ₄ : Ce, LaPO ₄ : Ce, Ce ( Mg, Ba) Al ₁₁ O ₁₉ , CeMgAl ₁₁ O ₁₈ : Ce, Ca ₃ (PO ₄ ) ₂ : Tl, Y (P, V) O ₄ , Y ₂ SiO ₅ : Ce, CaWO ₄ , CaWO ₄ : Pb The phosphor of is contained.

Non-patent document 1 discloses an AC type PDP in which a crystal emetic layer is formed on the discharge space side surface of the dielectric protective layer. According to the nonpatent literature 1, a crystal emetic layer contributes to the improvement of the discharge delay by supply of priming electrons, and the improvement of the luminous effect by the ultraviolet light emission of wavelength 250nm vicinity. However, this non-patent document 1 does not have a specific description about the material of a crystal emetic layer.

An object of the present invention is to provide a magnesium oxide powder which emits ultraviolet light with high efficiency when excited by ultraviolet light generated by gas discharge of Xe gas, which is formed on a dielectric protective layer of a gas discharge light emitting device such as an AC type PDP. It is in doing it.

In the present invention, the purity of magnesium oxide containing fluorine in the range of 0.01 to 10% by mass is 99.8% by mass or more (however, magnesium oxide purity is magnesium oxide purity in the total amount excluding fluorine contained), and the BET specific surface area is 0.1 Fluorine-containing magnesium oxide powder in the range of -30 m 2 / g.

Preferable embodiments of the fluorine-containing magnesium oxide powder of the present invention are as follows.

(1) Fluorine content exists in the range of 0.03-5 mass%.

(2) Magnesium oxide purity is 99.9 mass% or more.

(3) The BET specific surface area is in the range of 0.1-12 m 2 / g.

(4) An ultraviolet light emitting layer is formed on the surface of the dielectric protective layer discharge space side of an AC plasma display panel.

The present invention also provides a magnesium oxide raw material powder having a magnesium oxide purity of 99.95 mass% or more and a BET specific surface area in the range of 5 to 150 m 2 / g in the presence of a fluorine source or under a fluorine-containing gas atmosphere. It also exists in the manufacturing method of the said fluorine-containing magnesium oxide powder of this invention formed by baking at the temperature more than 10 degreeC for 10 minutes or more.

Preferred embodiments of the production method of the present invention are as follows.

(1) The magnesium oxide raw material powder is fired in the presence of magnesium fluoride powder having a purity of 99.0% by mass or more.

(2) The baking temperature of magnesium oxide raw material powder is in the range of 1000-1500 degreeC.

(3) The firing time of the magnesium oxide raw material powder is in the range of 20 minutes to 1 hour.

The present invention also exists in a magnesium oxide film produced from the fluorine-containing magnesium oxide powder of the present invention.

The present invention also exists in an ultraviolet light emitting layer formed on the surface of the dielectric protective layer discharge space side of an alternating plasma display panel manufactured from the fluorine-containing magnesium oxide powder of the present invention.

To practice the invention  Best form for

The fluorine contained in the fluorine-containing magnesium oxide powder of the present invention is partially substituted with oxygen in the magnesium oxide crystal, which has the effect of causing partial defects in the crystal. It is considered that the fluorine-containing magnesium oxide powder of the present invention is improved in the emission efficiency of ultraviolet light due to partial crystal defects caused by the presence of fluorine.

The fluorine-containing magnesium oxide powder of the present invention is in the range of 0.01 to 10% by mass, preferably 0.03 to 5% by mass, more preferably 0.03 to 3% by mass, particularly preferably 0.03 to 0.1% by mass. It contains. Although fluorine exists mainly in the crystal | crystallization of magnesium oxide as mentioned above, it may partially precipitate as magnesium fluoride. Magnesium oxide purity except fluorine contained in fluorine-containing magnesium oxide powder is 99.8 mass% or more, Preferably it is 99.9 mass% or more. In addition, the purity of magnesium oxide is the total content of impurity elements (containing 0.001% by mass or more relative to the total amount of the fluorine-containing magnesium oxide powder) excluding fluorine, magnesium and oxygen when the total amount of the fluorine-containing magnesium oxide powder is 100. And fluorine content can be obtained by the following formula.

Purity of magnesium oxide (mass%) = [total content of 1-impurity element (mass%) / {100-fluorine content (mass%)}] × 100

The fluorine-containing magnesium oxide powder of the present invention has a BET specific surface area in the range of 0.1 to 30 m 2 / g, preferably in the range of 0.1 to 12 m 2 / g.

The fluorine-containing magnesium oxide powder of the present invention is a magnesium oxide raw material powder having a magnesium oxide purity of 99.95% by mass or more and a BET specific surface area in the range of 5 to 150 m 2 / g, preferably 7 to 50 m 2 / g. In the presence of or in the atmosphere of a fluorine-containing gas, it can be produced by a method consisting of baking at a temperature of 850 ℃ or more for 10 minutes or more.

As magnesium oxide raw material powder used for manufacture of fluorine-containing magnesium oxide powder, it is preferable that it is magnesium oxide powder manufactured by the vapor phase synthetic oxidation method. The gas phase synthetic oxidation method is a method of producing magnesium oxide powder by bringing metal magnesium vapor into contact with an oxygen-containing gas in the gas phase to oxidize the metal magnesium vapor.

It is preferable to use magnesium fluoride powder as the fluorine source. It is preferable that the magnesium fluoride powder used as a fluorine source is 99 mass% or more in purity. When baking magnesium oxide raw material powder in presence of a fluorine source, it is preferable to mix a magnesium oxide raw material powder and a fluorine source uniformly before baking.

As the fluorine-containing gas, it is preferable to use hydrogen fluoride gas, ammonium fluoride, a fluorine-containing organic compound (CF ₄ , C ₂ F ₆ , C ₃ F _8, etc.) or a gas obtained by heating and vaporizing magnesium fluoride powder.

When the magnesium oxide raw material powder is calcined for 10 minutes or more at a temperature of 850 ° C. or higher in the presence of a fluorine source or in an atmosphere of a fluorine-containing gas, the primary particles of the magnesium oxide raw material powder are grown by injecting fluorine into the crystal. For this reason, the BET specific surface area of the fluorine-containing magnesium oxide powder obtained is lower than that of the magnesium oxide raw material powder. The BET specific surface area of the obtained fluorine-containing magnesium oxide powder is preferably in the range of 1 to 50%, particularly preferably in the range of 3 to 30% with respect to the magnesium oxide raw material powder.

In the present invention, the firing temperature when firing the magnesium oxide raw material powder in the presence of a fluorine source or in an atmosphere of a fluorine-containing gas is 850 ° C or higher, preferably 900 to 1500 ° C, particularly preferably 1000 to 1500 Is in the C range. The firing time is at least 10 minutes, preferably in the range of 20 minutes to 1 hour.

Metal other than magnesium can be added to the fluorine-containing magnesium oxide powder of this invention for the improvement of discharge characteristics. Examples of the metal added to the fluorine-containing magnesium oxide powder of the present invention include zinc, aluminum, silicon, calcium, strontium, barium, titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, manganese, iron, and cobalt. , Scandium, yttrium, lanthanum, cerium, neodymium, samarium, europium, gadolinium and dysprosium. Metals other than magnesium are added at the time of manufacture of the fluorine-containing magnesium oxide powder of this invention as oxide, carbonate, and nitrate, for example, and the addition amount of metal is 0.001-10 mass with respect to the whole fluorine-containing magnesium oxide powder. It is preferable to exist in the range of%, and it is preferable to exist in 0.01-1 mass% range.

Example

Example 1

(Production of Plastic Nos. 1 to 12)

Magnesium oxide (MgO) powder (2000A, manufactured by Ube Matterials, Purity: 99.98% by mass, BET specific surface area: 8.7 m ₂ / g) and magnesium fluoride (MgF ₂ ) powder produced by vapor phase synthetic oxidation method ( Purity: 99.1 mass%, BET specific surface area: 6.4 m 2 / g) were mixed in the amounts shown in Table 1 below to obtain a powder mixture. The obtained powder mixture was put in a 25 mL alumina crucible, and the lid was put in an alumina crucible and placed in an electric furnace, and the furnace temperature was raised to the temperature shown in Table 1 below at a temperature increase rate of 240 ° C / hour, followed by 30 minutes at that temperature. It was calcined by heating. Then, the furnace temperature was cooled to room temperature at the temperature-fall rate of 240 degree-C / hour. And the alumina crucible was picked up from the electric furnace, and baking products No.1-No.12 of the powder mixture were obtained.

About obtained baking products No.1-No.12, BET specific surface area, fluorine content, purity, and ultraviolet light emission intensity were measured. The results are shown in Table 2. In addition, fluorine content and ultraviolet light emission intensity were measured by the following method. ·

[Fluorine content]

The amount of fluorine in the solution which melt | dissolved the calcined product with hydrochloric acid and prepared it is measured by the method of 34.1 of JIS-0102 (factory drainage test method).

[Ultraviolet light emission intensity]

Ultraviolet light generated by gas discharge of Xe gas was irradiated to the fired product, and the ultraviolet light emission intensity near the emitted wavelength of 250 nm was measured. In addition, the value of Table 2 is a relative value which made the ultraviolet light emission intensity | strength of the baking product No. 1 100.

1 shows the relationship between the fluorine content of the fired materials Nos. 1 to 12 and the ultraviolet light emission intensity. In addition, in FIG. 1, the horizontal axis (fluorine content) and the vertical axis (ultraviolet light emission intensity) were shown by the number. As shown in Table 2 and Fig. 1, the fired products No. 2 to No. 12 having a fluorine content of 0.01% by mass or more are 10 times higher than the fired product No. 1 having a fluorine content of 0.0084% by mass. It can be seen that the external light emission intensity is shown.

Example 2

Magnesium oxide powder (500A, manufactured by Ube Matterials Co., Ltd., purity: 99.98 mass%, BET specific surface area: 39.3 m 2 / g) prepared by vapor phase synthetic oxidation method, 5.0 g of magnesium fluoride (MgF ₂ ) powder (purity : 99.1 mass%, BET specific surface area: 6.4 m <2> / g) 0.05g was mixed and the powder mixture was obtained. The obtained powder mixture was carried out similarly to Example 1, and it baked by baking for 30 minutes on the conditions of the furnace temperature of 1200 degreeC.

The BET specific surface area, fluorine content, purity, and ultraviolet light emission intensity of the resulting fired product were measured. As a result, the BET specific surface area was 8.26 m 2 / g, the fluorine content was 0.27% by mass, the purity was 99.9% by mass, and the ultraviolet light emission intensity was a relative value obtained by setting the ultraviolet light emission intensity of the firing material No. 1 of Example 1 to 100. Was 3500.

[Effects of the Invention]

When fluorine-containing magnesium oxide powder of this invention is excited by the ultraviolet light produced | generated by the gas discharge of Xe gas, it will emit the ultraviolet light of wavelength 250nm vicinity with high efficiency. Therefore, by arranging the magnesium oxide film made from the fluorine-containing magnesium oxide powder of the present invention in the discharge space of a gas discharge light emitting device such as an AC PDP or a phosphor lamp, the amount of ultraviolet light emitted in the discharge space is increased, thereby forming the second phosphor layer. Without particularly forming, it is possible to increase the amount of visible light emitted from the gas discharge light emitting device. The magnesium oxide film produced from the fluorine-containing magnesium oxide powder of the present invention is particularly useful as an ultraviolet light emitting layer formed on the surface of the dielectric protective layer discharge space side of AC type PDP. Moreover, by using the manufacturing method of this invention, magnesium oxide powder with high emission efficiency of an ultraviolet light can be industrially advantageously manufactured.

Claims (4)

A method for producing a fluorine-containing magnesium oxide powder, which is placed in a crucible with a powder mixture of magnesium oxide raw material powder and a fluorine source powder, and calcined with a lid on the crucible. The method of claim 1,
A method for producing a fluorine-containing magnesium oxide powder, wherein the fluorine-containing powder is magnesium fluoride powder. The method of claim 1,
The magnesium oxide raw material powder has a purity of 99.95 mass% or more and a BET specific surface area in the range of 5 to 150 m ² / g. The method of claim 1,
The said powder mixture is a manufacturing method of the fluorine-containing magnesium oxide powder which contains the said fluorine source powder in the range of 0.015-10 / 3 mass parts with respect to 5 mass parts of said magnesium oxide raw material powders.

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