JP2006152242A - Luminous material and process for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an aluminate luminous material that is excellent in afterglow property without the use of an expensive rare earth element as a coactivator. <P>SOLUTION: A europium-activated alkaline earth metal aluminate luminous material is characterized in that the afterglow brightness thereof (Y<SB>23°C</SB>and<SB>120 min</SB>) exhibited 120 min after photo-irradiation discontinuation at 23°C is at least 0.007 Cd/m<SP>2</SP>, and that the temperature dependence (TD) of afterglow brightness expressed by the ratio of afterglow brightness thereof (Y<SB>80°C</SB>) exhibited 10 min after photo-irradiation discontinuation at 80°C to afterglow brightness thereof (Y<SB>23°C</SB>) exhibited 10 min after photo-irradiation discontinuation at 23°C, Y<SB>80°C</SB>/Y<SB>23°C</SB>, is at least 1. This luminous material realizes prolonged afterglow and further exhibits thermoluminescence over a wide temperature range even without the use of an expensive rare earth element, such as dysprosium, as a co-activator. Thus the material can be used over a wide temperature range and the environment for use of the material is almost unlimited. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a europium-activated alkaline earth metal aluminate-based phosphorescent material having excellent afterglow characteristics at high temperatures.

Among phosphors, those having a long afterglow time are known as phosphorescent materials, and are widely used in fields such as daily necessities, weakly illuminated night signboards, and watches. Although strontium aluminate (SrAl ₂ O ₄ ) activated with europium has fluorescence characteristics, it has low afterglow luminance and is not useful as a phosphorescent material (see, for example, Non-Patent Document 1). Also, using aluminum oxide, strontium carbonate, sodium carbonate, and europium oxide as raw materials, 1 mol% of europium, 2 mol% of sodium, and 1 mol% of boron oxide as a flux are mixed with the host cation, and heated and fired. It has been reported that when europium activated strontium aluminate is produced, the phosphorescence disappears or the phosphorescence characteristics hardly change compared to the case where sodium is not added (see Non-Patent Document 2). For this reason, a long afterglow is imparted to this material by further adding a rare earth element such as dysprosium as a coactivator and used as a phosphorescent material (see, for example, Patent Document 1).

“Phosphor Handbook” (USA), CRC Press, 1998, p. 655-656 “JOURNAL OF SOLID STATE CHEMISTRY”, 171 (2003) p. 114-122 JP 7-11250 A, page 2

  However, since the europium activated strontium aluminate containing the rare earth element described in Patent Document 1 as a coactivator has a thermoluminescence peak in the temperature range of 60 to 75 ° C., the interior of a summer automobile (80 ° C. When used at a certain temperature), there is a problem that long-lasting afterglow cannot be obtained due to thermoluminescence, and there is a demand for a material exhibiting long afterglow with sufficient brightness at high temperatures.

  The present inventor has made various studies to find a europium-activated alkaline earth metal aluminate-based phosphorescent material having excellent afterglow characteristics at high temperatures. When producing the phosphorescent material, an alkali metal compound and a specific amount of boron compound The phosphorescent material obtained by mixing and firing the raw material exhibits characteristic behavior not only in afterglow characteristics at room temperature but also in the temperature characteristics of afterglow brightness, without using a co-activator. The headline and the present invention were completed.

That is, according to the present invention, the afterglow brightness Y _{23 ° C. and} 120 min after 120 minutes of light irradiation stop at a temperature of _{23 ° C.} is at least 0.007 Cd / m ² , and light irradiation stop 10 minutes at a temperature of 80 ° C. Afterglow luminance Y The ratio of the afterglow luminance Y at _{80 ° C.} and the afterglow luminance Y _{23 ° C.} after 10 minutes at the temperature of _{23 ° C.} Y _{80 °} C./Y _{23 ° C.} Temperature characteristic of the afterglow luminance (TD ) Is at least 1, a europium-activated alkaline earth metal aluminate-based phosphorescent material.

  Further, the present invention relates to the above-mentioned europium activated alkaline earth metal aluminate-based phosphorescent material, containing an alkali metal and boron, wherein the boron content is 3 to 50 mol% with respect to the alkaline earth metal. Features.

  Furthermore, the present invention is a method for producing the above europium-activated alkaline earth metal aluminate-based phosphorescent material, comprising an alkali metal compound, an aluminum compound, an alkaline earth metal compound, a europium compound, and a boron compound, and boron It is characterized by heating and baking the mixture whose content is 3-50 mol% with respect to alkaline-earth metal.

  The europium-activated alkaline earth metal aluminate phosphorescent material of the present invention has long persistence and exhibits thermoluminescence in a wide temperature range without using expensive rare earth elements such as dysprosium as a co-activator. Therefore, it can be used in a wide temperature range and is not easily restricted by the use environment.

The present invention has an afterglow brightness Y _{23 ° C.} after 120 minutes of light irradiation stop at a temperature of _{23 ° C. and 120 min} of at least 0.007 Cd / m ² , and 10 minutes after the light irradiation stop at a temperature of 80 ° C. Afterglow luminance Y The ratio of the afterglow luminance Y to _{23 ° C.} 10 minutes after the light irradiation is stopped at a temperature of _{80 ° C.} and 23 ° C. The temperature characteristic (TD) of the afterglow luminance expressed by Y _{80 °} C./Y _{23 ° C.} It is at least 1.

In the present invention, the afterglow luminance Y _{23 ° C. and 120 min} is a value measured by the following method.
(Measurement method of Y _{23 ° C, 120 min} )
Using a D65 fluorescent lamp on a sample kept in a dark place at a temperature of 23 ° C. for about one day, after irradiating light with an illuminance of 200 lx for 20 minutes, the afterglow luminance from the sample after 120 minutes of irradiation stop was measured with a luminance meter ( It was measured using Topcon Co., Ltd. product: BM-5A) _, and it was set as _{Y23 degreeC} and _120min . During the measurement, the temperature of the sample is kept at 23 ° C.

In the present invention, the temperature characteristic (TD) of afterglow brightness uses a value measured by the following method.
(Measurement method of TD)
In order to make the sample kept in a dark place at 23 ° C and 80 ° C for about 1 day in a dark excitation condition, using xenon lamp, irradiate light with 150,000 lx illuminance for 3 minutes, then stop irradiation The afterglow luminance from the sample after 10 minutes was measured using a luminance meter (Topcon Co., Ltd .: BM-5A) (Y _{23 ° C.} and Y _{80 ° C.} , respectively) to obtain Y _{80 °} C./Y _{23 ° C.} , TD. During the measurement, the temperature of the sample is kept at 23 ° C. and 80 ° C., respectively.

The phosphorescent material of the present invention has an afterglow luminance Y _{23 ° C. and 120 min} measured by the above method of at least 0.007 Cd / m ² . The luminance of 0.007 Cd / m ² is a luminance that is visible in a dark place. Even in JISZ9107 (safety sign board), the phosphorescence (afterglow) luminance after 60 minutes is 0.007 Cd / m ² or more. It is prescribed.

  Furthermore, the phosphorescent material of the present invention has a temperature characteristic (TD) of afterglow luminance measured by the above method of at least 1. Europium-activated alkaline earth metal aluminates using rare earth elements such as dysprosium as coactivators currently used have sufficient afterglow properties at room temperature, but afterglow brightness at high temperatures (80 ° C) Decreases and becomes a value smaller than 1 when expressed in TD. On the other hand, the phosphorescent material of the present invention has a feature that TD is at least 1, and the phosphorescent property at high temperature (80 ° C.) is superior to the phosphorescent property at normal temperature. It is. Preferably, TD is 1-4, and more preferably, TD is 2-4.

  Furthermore, the present invention relates to the above europium-activated alkaline earth metal aluminate-based phosphorescent material that contains an alkali metal and boron, and that the boron content is 3 to 50 mol% with respect to the alkaline earth metal. Features.

  In the present invention, the amount of europium contained as an activator is preferably in the range of 0.002 to 20 mol% with respect to the alkaline earth metal. If the amount of europium is less than the above range, it is difficult to impart long persistence, and if it is greater than the above range, further improvement in long persistence cannot be expected.

  Moreover, the amount of the alkali metal contained in the present invention is preferably in the range of 0.002 to 30 mol% with respect to the alkaline earth metal. If it is more than the above range, further improvement in the long persistence at high temperature cannot be expected. A more preferable range is 0.01 to 5 mol%. In the luminous material of this invention, lithium, sodium, potassium, rubidium, or cesium may be included individually as alkali metal, and multiple types may be included, respectively.

  The alkaline earth metal constituting the europium-activated alkaline earth metal aluminate-based phosphorescent material of the present invention can be magnesium, calcium, strontium and / or barium, but develops high temperature long persistence. Above, strontium is preferable.

  Furthermore, the europium activated alkaline earth metal aluminate-based phosphorescent material of the present invention further comprising at least one co-activator selected from dysprosium, neodymium, praseodymium, terbium, and tin, while maintaining afterglow characteristics at high temperatures The afterglow luminance at room temperature can be further increased, which is preferable.

  The content of the coactivator is preferably 0.002 to 20 mol% with respect to the alkaline earth metal. If the amount of the co-activator is less than the above range, it is difficult to further improve the afterglow luminance at room temperature, and even if the amount is more than the above range, further improvement in luminance at room temperature cannot be expected. On the contrary, the luminous characteristics at high temperatures are reduced. A more preferable range of the co-activator is 0.002 to 5 mol%.

The host crystal structure of the phosphorescent material of the present invention is not particularly limited as long as it is an alkaline earth metal aluminate-based material. More specifically, a stuffed tridymite structure such as MAl ₂ O ₄ is used. And an orthorhombic structure such as M ₄ Al ₁₄ O ₂₅ (M represents an alkaline earth metal). Among them, the stuffed tridymite structure is a preferable structure because it is relatively easy to synthesize.

  Next, the present invention is a method for producing a europium-activated alkaline earth metal aluminate-based phosphorescent material, comprising an alkali metal compound, an aluminum compound, an alkaline earth metal compound, a europium compound and a boron compound, and containing boron A mixture having an amount of 3 to 50 mol% with respect to the alkaline earth metal is heated and fired.

  Examples of aluminum compounds that can be used as raw materials include aluminum oxide, aluminum hydroxide, aluminum nitride, aluminum chloride, aluminum sulfate, aluminum nitrate, aluminum acetate, aluminum oxalate, aluminum citrate, and strontium aluminate. And the use of chemically stable aluminum oxide is preferred.

  As the alkaline earth metal compound, a magnesium compound, a calcium compound, a strontium compound, and a barium compound can be used alone or in combination, and a strontium compound is preferably used. More specifically, examples of the strontium compound include strontium carbonate, strontium hydroxide, strontium nitride, strontium chloride, strontium sulfate, strontium nitrate, strontium acetate, strontium oxalate, strontium citrate, strontium oxide, and strontium aluminate. The use of chemically stable strontium carbonate without deliquescence is preferred. Similarly, magnesium compounds, calcium compounds, and barium compounds can be used according to the above examples of strontium compounds such as carbonates and hydroxides thereof. The mixing ratio of the alkaline earth metal compound and the aluminum compound is preferably in the range of 0.02 to 3.0, more preferably 0.08 to 1.5 in terms of molar ratio. In order to obtain an alkaline earth metal aluminate having a stuffed tridymite structure, the mixing ratio is preferably in the range of 0.37 to 0.75, and more preferably in the range of 0.42 to 0.70. Is more preferable.

  Examples of europium compounds include europium oxide, europium chloride, europium oxalate, europium sulfide, europium sulfate, and europium nitrate. The mixing ratio of the europium compound and the alkaline earth metal compound is preferably in the range of 0.00002 to 0.2 in terms of molar ratio.

  Further, examples of the boron compound include boric acid and boron oxide. As the boron compound, a composite compound with an alkali metal compound described later, for example, lithium metaborate, lithium tetraborate, potassium metaborate, potassium tetraborate, sodium metaborate, sodium tetraborate and the like may be used.

  And as an alkali metal compound, a lithium compound, a sodium compound, a potassium compound, a cesium compound, and a rubidium compound can be used. More specifically, lithium compounds include lithium carbonate, lithium hydroxide, lithium chloride, lithium sulfate, lithium nitrate, lithium acetate, lithium oxalate, lithium citrate, lithium oxide, lithium aluminate, lithium metaborate, and tetraborate. Examples include lithium and lithium fluoride. Examples of the sodium compound include sodium carbonate, sodium hydroxide, sodium chloride, sodium sulfate, sodium nitrate, sodium oxalate, sodium bicarbonate, sodium fluoride and the like. Examples of potassium compounds include potassium carbonate, potassium hydroxide, potassium nitride, potassium chloride, potassium sulfate, potassium nitrate, potassium acetate, potassium oxalate, potassium citrate, potassium oxide, potassium aluminate, potassium tetraborate, and potassium fluoride. It is done. Examples of the cesium compound include cesium carbonate, cesium hydroxide, cesium chloride, cesium sulfate, cesium nitrate, and cesium fluoride. Further, examples of the rubidium compound include rubidium carbonate, rubidium hydroxide, rubidium chloride, rubidium sulfate, rubidium nitrate, rubidium acetate, rubidium oxalate, rubidium oxide, and rubidium fluoride. The mixing ratio of the alkali metal compound and the alkaline earth metal compound is preferably in the range of 0.00002 to 0.5, more preferably 0.0005 to 0.1 in terms of molar ratio.

  In the present invention, it is preferable that the raw material mixture further contains a compound of at least one co-activating element selected from dysprosium, neodymium, praseodymium, terbium and tin.

  Examples of the dysprosium compound include dysprosium oxide, dysprosium chloride, dysprosium oxalate, dysprosium sulfide, dysprosium sulfate, dysprosium nitrate, and dysprosium carbonate. Examples of the neodymium compound include neodymium oxide, neodymium chloride, neodymium oxalate, neodymium sulfide, neodymium sulfate, neodymium nitrate, and neodymium carbonate. Examples of the praseodymium compound include praseodymium oxide, praseodymium chloride, praseodymium oxalate, praseodymium sulfide, praseodymium sulfate, praseodymium nitrate, and praseodymium carbonate. Examples of the terbium compound include terbium oxide, terbium chloride, terbium oxalate, terbium sulfide, terbium sulfate, and terbium nitrate. Furthermore, examples of the tin compound include stannous oxide, stannic oxide, tin chloride, tin oxalate, tin sulfate, and tin nitrate. The mixing ratio of the co-activating element compound and the alkaline earth metal compound is preferably 0.00002 to 0.2, more preferably 0.0005 to 0.1 in terms of molar ratio.

  Next, the mixture of the above raw materials is heated and fired to obtain a europium-activated alkaline earth metal aluminate-based phosphorescent material. Heating and baking are preferably performed in a non-oxidizing atmosphere at a temperature in the range of 600 ° C to 1700 ° C. Examples of the non-oxidizing atmosphere include an inert atmosphere such as nitrogen, argon, neon, and krypton, and a reducing atmosphere obtained by mixing these with hydrogen. Among them, hydrogen: nitrogen (volume ratio) of 0: 1 to 1: 0 inert atmosphere or reducing atmosphere is preferable, and 0.0001: 0.9999 to 0.5: 0.5 reducing ability is more preferable. The atmosphere. Further, a more preferable range of the heating and firing temperature is a temperature in the range of 900 ° C. to 1600 ° C., more preferably 1100 ° C. to 1500 ° C. The heating time is not particularly limited, but is preferably 0.5 to 10 hours.

  The europium activated alkaline earth metal aluminate-based phosphorescent material of the present invention obtained by heating and firing can be appropriately pulverized by a known method to adjust the particle size according to the purpose of use. For example, general pulverization methods such as pin mill pulverization, ball mill pulverization, jet mill pulverization, and bantam mill pulverization can be employed.

  EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these Examples.

Example 1
5.019 g strontium carbonate (SrCO ₃ ), 0.070 g europium oxide (Eu ₂ O ₃ ), 4.078 g aluminum oxide (λ-Al ₂ O ₃ ) and 0.2073 g lithium tetraborate (Li ₂ B) ₄ O ₇ ) was mixed using an agate mortar. The blending ratio of the raw material powder is expressed as a molar ratio: Sr: Eu: Li: B: Al = 0.85: 0.01: 0.06: 0.12: 2. Next, the obtained mixture was put in an alumina crucible and heated and fired at a temperature of 1200 ° C. for 4 hours in a weak reducing atmosphere of hydrogen: nitrogen = 3 vol%: 97 vol%. The fired product was pulverized in an agate mortar to obtain a phosphorescent material (sample A-1) of the present invention.

Example 2
In Example 1, except that by adding a dysprosium oxide _{(Dy 2} O 3) _0.149g, to obtain a similarly treated phosphorescent material of the present invention (Sample A-2). The blending ratio of the raw material powder is expressed as a molar ratio: Sr: Eu: Li: Dy: B: Al = 0.85: 0.01: 0.06: 0.02: 0.12: 2.

Example 3
In Example 1, except that by adding praseodymium oxide _{(Pr 6} O 11) 0.014g, to obtain a similarly treated phosphorescent material of the present invention (Sample A-3). The blending ratio of the raw material powder is expressed as a molar ratio: Sr: Eu: Li: Pr: B: Al = 0.85: 0.01: 0.06: 0.002: 0.12: 2.

Example 4
In Example 1, except that added the terbium oxide _{(Tb 4} O 7) 0.015g, to obtain a similarly treated phosphorescent material of the present invention (Sample A-4). The blending ratio of the raw material powder is expressed as a molar ratio: Sr: Eu: Li: Tb: B: Al = 0.85: 0.01: 0.06: 0.002: 0.12: 2.

Example 5
In Example 1, except that tin oxide was added to _(SnO 2) 0.012 g, was obtained similarly treated phosphorescent material of the present invention (Sample A-5). The blending ratio of the raw material powder is expressed as a molar ratio: Sr: Eu: Li: Sn: B: Al = 0.85: 0.01: 0.06: 0.002: 0.12: 2.

Example 6
In Example 1, instead of using 0.2073 g of lithium tetraborate, 0.1979 g of boric acid (H ₃ BO ₃ ) and 0.1182 g of lithium carbonate (Li ₂ CO ₃ ) were used. 1 to obtain a phosphorescent material (sample A-6) of the present invention. In addition, the mixture ratio of raw material powder is Sr: Eu: Li: B: Al = 0.85: 0.01: 0.08: 0.08: 2.

Example 7
In Example 6, except that the lithium carbonate _(Li 2 CO ₃₎ from 0.1182g to 0.0074g obtained a phosphorescent material (Sample A-7) of the present invention was treated in the same manner as in Example 6 . In addition, the mixture ratio of raw material powder is Sr: Eu: Li: B: Al = 0.85: 0.01: 0.005: 0.08: 2.

Example 8
5.610 g strontium carbonate (SrCO ₃ ), 0.070 g europium oxide (Eu ₂ O ₃ ), 4.078 g aluminum oxide (λ-Al ₂ O ₃ ), 0.2956 g lithium carbonate (Li ₂ CO ₃₎ ) And 0.1296 g of lithium tetraborate (Li ₂ B ₄ O ₇ ) were mixed using an agate mortar. The blending ratio of the raw material powder is expressed as a molar ratio: Sr: Eu: Li: B: Al = 0.95: 0.01: 0.239: 0.08: 2. Firing was performed in the same manner as in Example 1 to obtain a phosphorescent material (Sample A-8) of the present invention.

Example 9
5.846 g strontium carbonate (SrCO ₃ ), 0.070 g europium oxide (Eu ₂ O ₃ ), 4.078 g aluminum oxide (λ-Al ₂ O ₃ ), 0.111 g potassium carbonate (K ₂ CO ₃₎ ) And 0.1979 g of boric acid (H ₃ BO ₃ ) were mixed using an agate mortar. The blending ratio of the raw material powder is expressed as a molar ratio: Sr: Eu: K: B: Al = 0.99: 0.01: 0.04: 0.08: 2. Firing was performed in the same manner as in Example 1 to obtain a phosphorescent material (Sample A-9) of the present invention.

Example 10
5.846 g strontium carbonate (SrCO ₃ ), 0.070 g europium oxide (Eu ₂ O ₃ ), 4.078 g aluminum oxide (λ-Al ₂ O ₃ ), 0.185 g rubidium carbonate (Rb ₂ CO ₃₎ ) And 0.1979 g of boric acid (H ₃ BO ₃ ) were mixed using an agate mortar. The blending ratio of the raw material powder is expressed as a molar ratio: Sr: Eu: Rb: B: Al = 0.99: 0.01: 0.04: 0.08: 2. Firing was performed in the same manner as in Example 1 to obtain a phosphorescent material (Sample A-10) of the present invention.

Example 11
In Example 9, the same procedure was followed except that 5.846 g of strontium carbonate (SrCO ₃ ) was changed to 5.019 g and 0.111 g of potassium carbonate (K ₂ CO ₃ ) was changed to 0.014 g. A material (Sample A-11) was obtained. In addition, the mixture ratio of raw material powder is Sr: Eu: K: B: Al = 0.85: 0.01: 0.005: 0.08: 2.

Example 12
In Example 9, phosphorescence of the present invention was obtained by the same treatment except that 5.846 g of strontium carbonate (SrCO ₃ ) was changed to 5.787 g and 0.111 g of potassium carbonate (K ₂ CO ₃ ) was changed to 0.028 g. A material (Sample A-12) was obtained. In addition, the mixture ratio of raw material powder is Sr: Eu: K: B: Al = 0.98: 0.01: 0.01: 0.08: 2.

Example 13
In Example 9, the same procedure was followed except that 5.846 g of strontium carbonate (SrCO ₃ ) was changed to 5.315 g and 0.111 g of potassium carbonate (K ₂ CO ₃ ) was changed to 0.249 g. A material (sample A-13) was obtained. In addition, the mixture ratio of raw material powder is Sr: Eu: K: B: Al = 0.90: 0.01: 0.09: 0.08: 2.

Example 14
In Example 10, the same procedure was followed except that 5.846 g of strontium carbonate (SrCO ₃ ) was changed to 5.019 g and 0.185 g of rubidium carbonate (Rb ₂ CO ₃ ) was changed to 0.023 g. A material (sample A-14) was obtained. In addition, the mixture ratio of raw material powder is Sr: Eu: Rb: B: Al = 0.85: 0.01: 0.005: 0.08: 2.

Example 15
In Example 10, phosphorescence of the present invention was treated in the same manner except that 5.846 g of strontium carbonate (SrCO ₃ ) was changed to 5.787 g and 0.185 g of rubidium carbonate (Rb ₂ CO ₃ ) was changed to 0.046 g. A material (sample A-15) was obtained. In addition, the mixture ratio of raw material powder is Sr: Eu: Rb: B: Al = 0.98: 0.01: 0.01: 0.08: 2.

Example 16
In Example 10, the same process was performed except that 5.846 g of strontium carbonate (SrCO ₃ ) was changed to 5.315 g, and 0.185 g of rubidium carbonate (Rb ₂ CO ₃ ) was changed to 0.416 g. A material (sample A-16) was obtained. In addition, the mixture ratio of raw material powder is Sr: Eu: Rb: B: Al = 0.90: 0.01: 0.09: 0.08: 2.

Example 17
5.787 g strontium carbonate (SrCO ₃ ), 0.070 g europium oxide (Eu ₂ O ₃ ), 0.0673 g neodymium oxide (Nd ₂ O ₃ ), 4.078 g aluminum oxide (λ-Al ₂ O ₃₎ ), 0.0148 g of lithium carbonate (Li ₂ CO ₃ ) and 0.198 g of boric acid (H ₃ BO ₃ ) were mixed using an agate mortar. The blending ratio of the raw material powder is expressed as a molar ratio: Sr: Eu: Li: Nd: B: Al = 0.98: 0.01: 0.01: 0.01: 0.08: 2. Firing was performed in the same manner as in Example 1 to obtain a phosphorescent material (Sample A-17) of the present invention.

Example 18
5.787 g strontium carbonate (SrCO ₃ ), 0.070 g europium oxide (Eu ₂ O ₃ ), 0.021 g sodium carbonate (Na ₂ CO ₃ ), 4.078 g aluminum oxide (λ-Al ₂ O ₃₎ ), 0.0148 g of lithium carbonate (Li ₂ CO ₃ ) and 0.198 g of boric acid (H ₃ BO ₃ ) were mixed using an agate mortar. The blending ratio of the raw material powder is expressed as a molar ratio: Sr: Eu: Li: Na: B: Al = 0.98: 0.01: 0.01: 0.01: 0.08: 2. Firing was performed in the same manner as in Example 1 to obtain a phosphorescent material (Sample A-18) of the present invention.

Example 19
5.315 g strontium carbonate (SrCO ₃ ), 0.070 g europium oxide (Eu ₂ O ₃ ), 0.111 g potassium carbonate (K ₂ CO ₃ ), 4.078 g aluminum oxide (λ-Al ₂ O ₃₎ ), 0.0887 g of lithium carbonate (Li ₂ CO ₃ ) and 0.198 g of boric acid (H ₃ BO ₃ ) were mixed using an agate mortar. The blending ratio of the raw material powder is expressed as a molar ratio: Sr: Eu: K: Li: B: Al = 0.90: 0.01: 0.04: 0.06: 0.08: 2. Firing was performed in the same manner as in Example 1 to obtain a phosphorescent material (Sample A-19) of the present invention.

Example 20
In Example 18, except having added sodium carbonate, it processed similarly to Example 18 and obtained the luminous material (sample A-20) of this invention. The blending ratio of the raw material powder is expressed as a molar ratio of Sr: Eu: Li: B: Al = 0.98: 0.01: 0.01: 0.08: 2.

Example 21
In Example 9, the phosphorescent material of the present invention was treated in the same manner as in Example 9 except that 0.275 g of cesium carbonate (Cs ₂ CO ₃ ) was used instead of 0.111 g of potassium carbonate (K ₂ CO ₃ ). (Sample A-21) was obtained. The blending ratio of the raw material powder is expressed as a molar ratio: Sr: Eu: Cs: B: Al = 0.99: 0.01: 0.04: 0.08: 2.

Example 22
5.019 g strontium carbonate (SrCO ₃ ), 0.070 g europium oxide (Eu ₂ O ₃ ), 4.078 g aluminum oxide (λ-Al ₂ O ₃ ), 0.0007 g lithium carbonate (Li ₂ CO ₃₎ ) And 0.1979 g of boric acid (H ₃ BO ₃ ) were mixed using an agate mortar. The blending ratio of the raw material powder is expressed as a molar ratio: Sr: Eu: Li: B: Al = 0.85: 0.01: 0.0005: 0.08: 2. Firing was performed in the same manner as in Example 1 to obtain a phosphorescent material (Sample A-22) of the present invention. When the elemental analysis of the obtained sample was carried out, it was Sr: Eu: Li: B: Al = 0.850: 0.010: 0.0009: 0.082: 1.95 in terms of molar ratio.

Example 23
The phosphorescent material of the present invention was treated in the same manner as in Example 22 except that 0.0028 g of potassium carbonate (K ₂ CO ₃ ) was used instead of 0.0007 g of lithium carbonate (Li ₂ CO ₃ ) in Example 22. (Sample A-23) was obtained. The blending ratio of the raw material powder is expressed as a molar ratio: Sr: Eu: K: B: Al = 0.85: 0.01: 0.001: 0.08: 2. The elemental analysis of the obtained sample was Sr: Eu: K: B: Al = 0.850: 0.009: 0.001: 0.090: 2.01 in terms of molar ratio.

Example 24
The phosphorescent material of the present invention was treated in the same manner as in Example 22 except that 0.0046 g of rubidium carbonate (Rb ₂ CO ₃ ) was used instead of 0.0007 g of lithium carbonate (Li ₂ CO ₃ ) in Example 22. (Sample A-24) was obtained. The mixing ratio of the raw material powder is expressed as a molar ratio of Sr: Eu: Rb: B: Al = 0.85: 0.01: 0.001: 0.08: 2. When the elemental analysis of the obtained sample was carried out, it was Sr: Eu: Rb: B: Al = 0.850: 0.010: 0.0001: 0.092: 1.91 in terms of molar ratio.

Example 25
The phosphorescent material of the present invention was treated in the same manner as in Example 22 except that instead of 0.0007 g of lithium carbonate (Li ₂ CO ₃ ) in Example 22, 1.106 g of potassium carbonate (K ₂ CO ₃ ) was used. (Sample A-25) was obtained. The blending ratio of the raw material powder is expressed as a molar ratio, Sr: Eu: K: B: Al = 0.85: 0.01: 0.4: 0.08: 2. When the elemental analysis of the obtained sample was carried out, it was Sr: Eu: K: B: Al = 0.850: 0.010: 0.18: 0.004: 1.93 in molar ratio.

Example 26
5.728 g strontium carbonate (SrCO ₃ ), 0.070 g europium oxide (Eu ₂ O ₃ ), 4.078 g aluminum oxide (λ-Al ₂ O ₃ ), 0.042 g sodium carbonate (Na ₂ CO ₃₎ ) And 0.056 g of boron oxide (B ₂ O ₃ ) were mixed using an agate mortar. The blending ratio of the raw material powder is expressed as a molar ratio of Sr: Eu: Na: B: Al = 0.97: 0.01: 0.02: 0.04: 2. Firing was performed in the same manner as in Example 1 to obtain a phosphorescent material (Sample A-26) of the present invention. When the elemental analysis of the obtained sample was carried out, it was Sr: Eu: Na: B: Al = 0.970: 0.009: 0.001: 0.031: 1.86 in terms of molar ratio.

Example 27
The phosphorescent material of the present invention was treated in the same manner as in Example 26 except that 0.1979 g of boric acid (H ₃ BO ₃ ) was used instead of 0.056 g of boron oxide (B ₂ O ₃ ). (Sample A-27) was obtained. The blending ratio of the raw material powder is expressed as a molar ratio: Sr: Eu: Na: B: Al = 0.97: 0.01: 0.02: 0.08: 2. Elemental analysis of the obtained sample showed Sr: Eu: Na: B: Al = 0.970: 0.009: 0.007: 0.073: 2.03 in terms of molar ratio.

Example 28
In Example 27, the same treatment was conducted as in Example 27 except that 5.728 g of strontium carbonate (SrCO ₃ ) was changed to 5.905 g and 0.042 g of sodium carbonate (Na ₂ CO ₃ ) was changed to 0.021 g. A phosphorescent material (Sample A-28) of the present invention was obtained. The blending ratio of the raw material powder is expressed as a molar ratio: Sr: Eu: Na: B: Al = 1.00: 0.01: 0.01: 0.08: 2. When the elemental analysis of the obtained sample was carried out, it was Sr: Eu: Na: B: Al = 1.000: 0.009: 0.003: 0.075: 1.924 when expressed in molar ratio.

Example 29
In Example 28, except for changing strontium carbonate 5.905g of (SrCO ₃₎ to 5.787g was obtained light-storing material of similarly treated by the present invention as in Example 28 (Sample A-29). The blending ratio of the raw material powder is expressed as a molar ratio of Sr: Eu: Na: B: Al = 0.98: 0.01: 0.01: 0.08: 2.

Example 30
In Example 29, except for changing strontium carbonate 5.787g of (SrCO ₃₎ to 5.610g was obtained light-storing material of similarly treated by the present invention as in Example 29 (Sample A-30). The mixing ratio of the raw material powder is expressed as a molar ratio of Sr: Eu: Na: B: Al = 0.95: 0.01: 0.01: 0.08: 2.

Example 31
In Example 28, except for changing strontium carbonate 5.905g of (SrCO ₃₎ to 5.019g was obtained light-storing material of similarly treated by the present invention as in Example 28 (Sample A-31). The blending ratio of the raw material powder is expressed as a molar ratio and is Sr: Eu: Na: B: Al = 0.85: 0.01: 0.01: 0.08: 2.

Example 32
Except for changing sodium carbonate _{(Na 2} CO 3) 0.021g to 0.011g in Example 31 to give the phosphorescent material (Sample A-32) of the present invention are treated in the same manner as in Example 31. The blending ratio of the raw material powder is expressed as a molar ratio: Sr: Eu: Na: B: Al = 0.85: 0.01: 0.005: 0.08: 2.

Example 33
In Example 12, except that the boric acid 0.197g _{(H 3} BO 3) to 0.099g was obtained light-storing material of similarly treated by the present invention as in Example 12 (Sample A-33). The blending ratio of the raw material powder is expressed as a molar ratio of Sr: Eu: K: B: Al = 0.98: 0.01: 0.01: 0.04: 2. Elemental analysis of the obtained sample showed Sr: Eu: K: B: Al = 0.980: 0.008: 0.001: 0.032: 1.87 in terms of molar ratio.

Example 34
In Example 33, except that the boric acid 0.099g _{(H 3} BO 3) to 0.297g was obtained light-storing material of similarly treated by the present invention as in Example 33 (Sample A-34). The blending ratio of the raw material powder is expressed as a molar ratio: Sr: Eu: K: B: Al = 0.98: 0.01: 0.01: 0.12: 2.

Example 35
In Example 34, except that the boric acid 0.297g _{(H 3} BO 3) to 0.396g was obtained light-storing material of similarly treated by the present invention as in Example 34 (Sample A-35). The blending ratio of the raw material powder is expressed as a molar ratio: Sr: Eu: K: B: Al = 0.98: 0.01: 0.01: 0.16: 2.

Example 36
In Example 12, except for changing strontium carbonate 5.787g of (SrCO ₃₎ to 5.905g was obtained light-storing material of similarly treated by the present invention as in Example 12 (Sample A-36). The blending ratio of the raw material powder is expressed as a molar ratio: Sr: Eu: K: B: Al = 1.00: 0.01: 0.01: 0.08: 2. Elemental analysis of the obtained sample showed Sr: Eu: K: B: Al = 1.00: 0.008: 0.0005: 0.067: 1.88 in terms of molar ratio.

Example 37
5.846 g Ba 10 ppm or less strontium carbonate (SrCO ₃ ), 0.070 g europium oxide (Eu ₂ O ₃ ), 4.078 g aluminum oxide (α-Al ₂ O ₃ ), 0.0148 g lithium carbonate ( Li ₂ CO ₃ ) and 0.198 g of boric acid (H ₃ BO ₃ ) were mixed using an agate mortar. The blending ratio of the raw material powder is expressed as a molar ratio: Sr: Eu: Li: B: Al = 0.99: 0.01: 0.01: 0.08: 2. Firing was performed in the same manner as in Example 1 to obtain a phosphorescent material (Sample A-37) of the present invention.

Example 38
5.787 g Ba 10 ppm or less strontium carbonate (SrCO ₃ ), 0.070 g europium oxide (Eu ₂ O ₃ ), 4.078 g aluminum oxide (γ-Al ₂ O ₃ ), 0.028 g potassium carbonate ( K ₂ CO ₃ ) and 0.198 g of boric acid (H ₃ BO ₃ ) were mixed using an agate mortar. The blending ratio of the raw material powder is expressed as a molar ratio: Sr: Eu: K: B: Al = 0.98: 0.01: 0.01: 0.08: 2. Firing was performed in the same manner as in Example 1 to obtain a phosphorescent material (Sample A-37) of the present invention.

Example 39
In Example 38, except having added 0.006 g of magnesium oxide (MgO), it processed similarly to Example 38 and obtained the luminous material (sample A-39) of this invention. The mixing ratio of the raw material powder is expressed as a molar ratio: Sr: Eu: K: B: Mg: Al = 0.98: 0.01: 0.01: 0.08: 0.004: 2.

Example 40
5.669 g Ba 10 ppm or less strontium carbonate (SrCO ₃ ), 0.070 g europium oxide (Eu ₂ O ₃ ), 4.078 g aluminum oxide (α-Al ₂ O ₃ ), 0.021 g sodium carbonate ( Na ₂ CO ₃ ), 0.149 g of dysprosium oxide (Dy ₂ O ₃ ), and 0.198 g of boric acid (H ₃ BO ₃ ) were mixed using an agate mortar. The blending ratio of the raw material powder is expressed as a molar ratio and is Sr: Eu: Na: Dy: B: Al = 0.96: 0.01: 0.01: 0.02: 0.08: 2. Firing was performed in the same manner as in Example 1 to obtain a phosphorescent material (Sample A-40) of the present invention.

Example 41
5.787 g strontium carbonate (SrCO ₃ ), 0.070 g europium oxide (Eu ₂ O ₃ ), 4.078 g aluminum oxide (γ-Al ₂ O ₃ ), 0.028 g potassium carbonate (K ₂ CO ₃₎ ), 0.075 g dysprosium oxide (Dy ₂ O ₃ ) and 0.198 g boric acid (H ₃ BO ₃ ) were mixed using an agate mortar. The blending ratio of the raw material powder is expressed as a molar ratio and is Sr: Eu: K: Dy: B: Al = 0.98: 0.01: 0.01: 0.01: 0.08: 2. Firing was performed in the same manner as in Example 1 to obtain a phosphorescent material (Sample A-41) of the present invention.

Comparative Example 1
In Example 1, instead of using 0.2073 g of lithium tetraborate, 0.1979 g of boric acid (H ₃ BO ₃ ) was used instead of using 0.2973 g of boric acid (H ₃ BO ₃ ). Sample B-1) was obtained. In addition, the mixture ratio of raw material powder is Sr: Eu: B: Al = 0.85: 0.01: 0.08: 2.

Comparative Example 2
5.728 g of strontium carbonate (SrCO ₃ ), 0.070 g of europium oxide (Eu ₂ O ₃ ), 4.078 g of aluminum oxide (λ-Al ₂ O ₃ ), 0.149 g of dysprosium oxide (Dy ₂ O ₃₎ ) And 0.198 g of boric acid (H ₃ BO ₃ ) were mixed using an agate mortar. The blending ratio of the raw material powder is expressed as a molar ratio: Sr: Eu: Dy: B: Al = 0.97: 0.01: 0.02: 0.08: 2. Subsequently, the obtained mixture was put in an alumina crucible and heated and fired at a temperature of 1400 ° C. for 2 hours in a weak reducing atmosphere of hydrogen: nitrogen = 3 vol%: 97 vol%. The fired product was pulverized with an agate mortar to obtain a phosphorescent material (sample B-2) as a comparative sample.

Comparative Example 3
In Example 26, except that 0.056 g of boron oxide (B ₂ O ₃ ) was changed to 0.028 g, a treatment was performed in the same manner as in Example 26 to obtain a phosphorescent material (sample B-3) as a comparative sample. The blending ratio of the raw material powder is expressed as a molar ratio: Sr: Eu: Na: B: Al = 0.97: 0.01: 0.02: 0.02: 2. When the elemental analysis of the obtained sample was carried out, it was Sr: Eu: Na: B: Al = 0.970: 0.009: 0.000: 0.018: 1.86 expressed by molar ratio.

Comparative Example 4
In Example 29, sodium carbonate _{(Na 2} CO 3) 0.042g except for not adding got phosphorescent material (Sample B-4) of the comparative sample was treated as in Example 29. In addition, the mixture ratio of raw material powder is Sr: Eu: B: Al = 0.98: 0.01: 0.08: 2.

  Powder X-ray diffraction of samples A-1 to 41 and B-1 to 4 obtained in Examples 1 to 41 and Comparative Examples 1 to 4 using an X-ray diffraction analyzer (RINT1000: manufactured by Rigaku Corporation) As a result, in all the samples, the main product phase had a stuffed tridymite structure. The powder X-ray diffraction pattern of Sample A-12 is shown in FIG.

  Furthermore, the luminous characteristics (relative afterglow luminance) of samples A-1 to 41 and B-1 to 4 obtained in Examples 1 to 41 and Comparative Examples 1 to 4 were evaluated as follows, together with the composition It is shown in Table 1.

(Measurement method of relative afterglow brightness)
A spectrofluorometer (FR-6500, manufactured by JASCO Corporation) was used for the measurement of the relative balance luminance.
In a time change measurement mode at room temperature (25 ° C.), the sample was irradiated with light having a wavelength of 400 nm for 3 minutes, and then the light irradiation was stopped, and the luminance after 10 minutes and 30 minutes was measured. The results are shown in Table 1 in terms of relative intensity with the afterglow luminance after 10 minutes of Sample B-1 being 100.

  Next, the temporal change of afterglow luminance was measured by the following method. The samples used are Samples A-1, A-2, A-12, A-9 and B-2. First, the pressed sample is set in a sample holder and held in a dark place for about 1 day. After exciting the sample for 20 minutes at 200 lx with a D65 fluorescent lamp, the temporal change in afterglow luminance from the sample was measured using a luminance meter (Topcon Co., Ltd .: BM-5A). The room temperature was maintained at 23 ° C. during the measurement. The results are shown in FIGS.

Moreover, thermoluminescence was measured by the following method.
The sample was irradiated with light having an illuminance of 150,000 lx for 3 minutes using a xenon lamp, and then the light emission was stopped and light emission from the sample was measured using a photosensor while raising the temperature at a rate of 0.2 K / s. The results of Samples A-9, A-12, and B-2 are shown in FIG. The sample B-2 of the comparative example shows thermoluminescence from 50 ° C. to 70 ° C., whereas the samples A-9 and A-12 of the present invention showed thermoluminescence peaks at a high temperature around 120 ° C. . From the fact that the peak temperature of thermoluminescence is high and strong, it can be seen that the carrier trap level is deep.

Further, Table 2 shows the results of afterglow luminance Y _{23 ° C., 120 min,} and temperature characteristics TD (Y _{80 °} C./Y _{23 ° C.} ) measured by the method described above. Their correlation diagram is shown in FIG.

FIG. 5 shows that the phosphorescent material of the present invention is in a characteristic position in the relationship between the afterglow luminance Y _{23 ° C., 120 min} and the temperature characteristic TD (Y _{80 °} C./Y _{23 ° C.} ). That is, in the prior art, (1) Alkaline earth metal aluminate-based phosphorescent material activated only by europium has excellent temperature characteristics but low afterglow luminance itself and cannot be put into practical use. ) In addition, alkaline earth metal aluminate phosphorescent materials co-activated with dysprosium have high afterglow brightness and are put to practical use, but their temperature characteristics are low, so they are restricted by the usage environment. On the other hand, it was found that the phosphorescent material of the present invention is excellent in both afterglow luminance and its temperature characteristics. Therefore, the phosphorescent material of the present invention is suitable not only for use at room temperature but also for use in a high temperature environment.

  The europium activated alkaline earth metal aluminate-based phosphorescent material of the present invention is suitable not only for use as a normal phosphorescent material but also for use at high temperatures.

It is a powder X-ray diffraction pattern of sample A-12. It is a figure which shows the time change of the afterglow brightness | luminance of sample A-1 and A-9. It is a figure which shows the time change of the afterglow brightness | luminance of sample A-2, A-12, and B-2. It is a figure which shows the thermoluminescence of sample A-9, A-12, and B-2. Afterglow luminance _{Y 23 ° C.,} a diagram showing the relationship between _120min and temperature characteristics _{TD (Y 80 ℃ / Y 23} ℃).

Claims (14)

Afterglow luminance Y after 120 minutes of light irradiation stop at a temperature of 23 ° C. _{23 ° C., 120 min} at least 0.007 Cd / m ² , and afterglow luminance Y after 10 minutes of light irradiation stop at a temperature of 80 ° C. The ratio of the afterglow luminance Y _{23 ° C.} 10 minutes after the light irradiation is stopped at _{80 ° C.} and 23 ° _C. The ratio Y _{80 °} C./Y _{23 ° C. The} afterglow luminance temperature characteristic (TD) is at least 1. Europium-activated alkaline earth metal aluminate-based phosphorescent material characterized by the above.   The europium-activated alkaline earth metal aluminate-based phosphorescent material according to claim 1, which contains an alkali metal and boron, and the boron content is 3 to 50 mol% with respect to the alkaline earth metal. .   The europium-activated alkaline earth metal aluminate-based phosphorescent material according to claim 1, comprising 0.002 to 20 mol% of europium with respect to the alkaline earth metal.   The europium-activated alkaline earth metal aluminate-based phosphorescent material according to claim 2, comprising 0.002 to 30 mol% of an alkali metal with respect to the alkaline earth metal.   The europium-activated alkaline earth metal aluminate-based phosphorescent material according to claim 1, wherein the alkaline earth metal is strontium.   The europium-activated alkaline earth metal aluminate-based phosphorescent material according to claim 1, further comprising at least one co-activator selected from dysprosium, neodymium, praseodymium, terbium, and tin.   The europium-activated alkaline earth metal aluminate-based phosphorescent material according to claim 6, comprising 0.002 to 20 mol% of a co-activator with respect to the alkaline earth metal.   The europium-activated alkaline earth metal aluminate-based phosphorescent material according to claim 1, wherein the base crystal has a stuffed tridymite structure.   It is characterized by heating and firing a mixture containing an alkali metal compound, an aluminum compound, an alkaline earth metal compound, a europium compound, and a boron compound, wherein the boron content is 3 to 50 mol% with respect to the alkaline earth metal. A method for producing a europium activated alkaline earth metal aluminate phosphorescent material.   The method for producing a europium-activated alkaline earth metal aluminate phosphorescent material according to claim 9, wherein the alkaline earth metal compound is a strontium compound.   The europium-activated alkaline earth metal aluminate-based phosphorescent material according to claim 10, wherein the mixture further contains a compound of at least one co-activator element selected from dysprosium, neodymium, praseodymium, terbium and tin. Manufacturing method.   The mixing ratio of the alkaline earth metal compound and the aluminum compound is 0.02 to 3.0 in molar ratio, and the mixing ratio of the alkali metal compound and the alkaline earth metal compound is 0.00002 to 0.5 in molar ratio. The production ratio of europium-activated alkaline earth metal aluminate-based phosphorescent material according to claim 9, wherein the mixing ratio of the europium compound and the alkaline earth metal compound is 0.00002 to 0.2 in molar ratio. Method.   The europium-activated alkaline earth metal aluminate-based phosphorescent material according to claim 11, wherein the mixing ratio of the compound of the co-activating element and the alkaline earth metal compound is 0.00002 to 0.2 in terms of molar ratio. Manufacturing method. The method for producing a europium-activated alkaline earth metal aluminate-based phosphorescent material according to claim 9, which is heated and fired at a temperature in the range of 600 to 1700 ° C. in a non-oxidizing atmosphere.

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