JP2002294229A - Phosphor manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique for preventing inclusion of impurities adversely affecting stimulable phosphor characteristics and for obtaining at the same time with a high yield pulverized stimulable phosphor particles or stimulable phosphor precursor particles in pulverizing aggregated particles which are generated when stimulable phosphor particles or stimulable phosphor precursor particles present in a dispersion medium are subjected to solid-liquid separation and dried in a stimulable phosphor manufacturing process. SOLUTION: The phosphor manufacturing method comprises pulverizing aggregated particles, generated in the process of solid-liquid separation from a particle dispersion or drying, in the presence of a rotating pulverizing blade without using a pulverizing medium in a moving vessel.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a phosphor, and more particularly to a method suitable for producing a rare earth-activated alkaline earth metal fluorinated halide stimulable phosphor.

[0002]

2. Description of the Related Art A radiation image recording / reproducing method using a stimulable phosphor described in JP-A-55-12145 or the like is known as an effective diagnostic means which can replace the conventional radiographic method.

This method utilizes a radiation image conversion panel (also referred to as a stimulable phosphor sheet) containing a stimulable phosphor, and irradiates radiation transmitted through a subject or emitted from a subject. The stimulable phosphor is absorbed by a stimulable phosphor, and the stimulable phosphor is excited in a time series with electromagnetic waves such as visible light and ultraviolet rays (referred to as excitation light). ), The fluorescence is photoelectrically read, an electric signal is obtained, and a radiation image of a subject or a subject is reproduced as a visible image based on the obtained electric signal.

After the conversion panel has been read, the remaining image is erased and used for the next photographing. According to this method, there is an advantage that a radiographic image with a large amount of information can be obtained with a much smaller exposure dose than a radiographic method using a radiographic film and an intensifying screen in combination.

In the radiographic method, a film is consumed each time a radiograph is taken, whereas the radiographic image conversion panel is used repeatedly, which is advantageous in terms of resource conservation and economic efficiency.

The radiation image conversion panel comprises only a support and a stimulable phosphor layer or a self-supporting stimulable phosphor layer provided on the surface of the support. Consisting of a stimulable phosphor and a binder dispersingly supporting the phosphor,
Some are composed only of aggregates of stimulable phosphors formed by a vapor deposition method or a sintering method.

[0007] In addition, there is also known one in which a polymer substance is impregnated in the gaps of the aggregate. Further, on the surface of the stimulable phosphor layer opposite to the support side, a protective film composed of a polymer film or an inorganic vapor-deposited film is usually provided.

The stimulable phosphor is usually 400 to 90.
Wavelength of 300 to 500 by the excitation light in the range of 0 nm.
Those exhibiting stimulated emission in the range of nm are generally used, and are disclosed in JP-A-55-12145 and JP-A-55-160078.
No. 56-74175, No. 56-116777,
57-23673, 57-23675, 58
-206678, 59-27289, 59-2
No. 7980, No. 59-56479, No. 59-5648
No. 0, etc .; rare earth element-activated alkaline earth metal fluorohalide-based phosphors;
No. 0-84381, No. 60-106752, No. 60-
No. 166379, No. 60-221483, No. 60-2
No. 28592, No. 60-228593, No. 61-23
No. 679, No. 61-120882, No. 61-1208
No. 83, No. 61-120885, No. 61-23548
No. 6, 61-235487, etc .; divalent europium-activated alkaline earth metal fluorohalide-based phosphors; rare earth element-activated oxyhalide phosphors described in JP-A-55-12144; Cerium-activated trivalent metal oxyhalide phosphor described in Kaikai 58-69281; bismuth-activated alkali metal halide phosphor described in JP-A-60-70484; JP-A-60-141783;
JP-A-60-157100, divalent europium-activated alkaline earth metal halophosphate phosphor described in JP-A-60-157100;
57099, divalent europium-activated alkaline earth metal haloborate phosphors described in JP-A-60-21735
No. 4, divalent europium-activated alkaline earth metal hydride halide phosphor described in JP-A No. 61-21173;
And 21182, cerium-activated rare earth composite halide phosphors described in JP-A-61-40390; cerium-activated rare earth halophosphate phosphors described in JP-A-61-40390;
No. 8151, a divalent europium-activated cerium rubidium halide phosphor described in JP-A-60-78151
And a divalent europium-activated alkaline earth metal fluorinated halide containing iodine, a rare earth element containing iodine, and the like. It is known that an activated oxyhalide phosphor and a bismuth-activated alkali metal halide phosphor containing iodine exhibit high-luminance stimulated emission.

[0009] Further, as the use of a radiation image conversion method using a stimulable phosphor has progressed, it has been required to further improve the image quality of the obtained radiation image, for example, the sharpness and the graininess. Was. The method for producing the stimulable phosphor described above is a method called a solid phase method or a sintering method, in which pulverization after firing is indispensable, and it is difficult to control the particle shape which affects sensitivity and image performance. There is a problem that there is.

[0010] Among the means for improving the image quality of a radiographic image, making the stimulable phosphor finer and making the particle size of the finely stimulable phosphor uniform, that is, narrowing the particle size distribution. Is valid.

JP-A-9-291278 and JP-A-7-233
The method for producing a stimulable phosphor from a liquid phase disclosed in, for example, JP-A-369-369 is a method of obtaining a particulate stimulable phosphor precursor by adjusting the concentration of a phosphor raw material solution. This is effective as a method for producing a stimulable phosphor powder having a uniform distribution.

The stimulable phosphor precursor obtained by the present method is
It is necessary to perform firing at a high temperature in order to obtain photostimulable luminescence, but since the photostimulable phosphor precursor is present in fine particles in a solution, the photostimulable phosphor precursor and the solution After solid-liquid separation of the stimulable phosphor precursor and drying of the stimulable phosphor precursor, baking is known.

At this time, the stimulable phosphor precursor after drying is
Fine primary particles exist as aggregated particles that are aggregated in a lump, and in order to uniformly bake individual primary particles,
It is necessary to break up the aggregated particles.

Further, as a method for preventing sintering during firing, a method is known in which at least one selected from metal oxides or metal oxide raw materials is used in a firing step as a sintering inhibitor.

Specific metal oxides include MgO, C
aO, Al ₂ O ₃ , SiO ₂ , TiO ₂ , ZrO ₂ , Ta ₂ O
_{5 and the} like, as metal oxide raw materials that can be easily converted to the metal oxide at high temperature, nitrate, carbonate, sulfate,
Compounds such as hydroxides that are easily decomposed at high temperatures to form metal oxides are known.

In order to produce the above-mentioned stimulable phosphor particles exhibiting high-luminance stimulable luminescence with a uniform particle size distribution, the stimulable phosphor particles obtained through the solid-liquid separation and drying processes synthesized in the above liquid phase are obtained. It is necessary to crush the agglomerated particles of the stimulable phosphor precursor obtained into primary particles and to uniformly mix the sintering inhibitor with the crushed stimulable phosphor precursor.

As a method of crushing the aggregated particles into primary particles, ball mills, vibrating mills, sand mills and the like using beads of glass, alumina, zirconia or the like having a diameter of 30 mm or less as a crushing medium are known. It is difficult to avoid mixing of impurities which have an adverse effect on the stimulable phosphor characteristics due to abrasion between beads or beads and the inner wall surface of the apparatus during pulverization.

Further, it is known that the stimulable phosphor precursor after grinding adheres to the bead surface, and as a result, the yield of the crushed stimulable phosphor precursor relative to the amount of the pulverized raw material is significantly reduced. I have.

On the other hand, as a method for mixing the stimulable phosphor precursor and the sintering inhibitor, a mixing device such as a V blender is known.

The mixing device represented by the present device is suitable for mixing the crushed primary particles with the sintering inhibitor.
The action of breaking up the aggregated particles is insufficient.

As a method for moisture-proofing the stimulable phosphor particles, a method of coating the surface of the stimulable phosphor particles with a silane coupling agent or the like is disclosed in JP-A-10-129482. Also in the method, the stimulable phosphor particles coated with the silane coupling agent and the like are present in the dispersion medium,
Aggregated particles are formed through solid-liquid separation and drying processes.

The stimulable phosphor subjected to the moisture-proof treatment is generally subjected to a classification step of narrowing the particle size distribution from the viewpoint of improving the quality of a radiographic image.

At this time, the moisture-proofed stimulable phosphor particles in the agglomerated state have poor powder fluidity and are difficult to supply quantitatively to the classification step. Occurs.

Also in this pulverization, it has been strongly desired to avoid mixing of impurities during the pulverization and to obtain moisture-proof treated stimulable phosphor particles pulverized at a high yield.

[0025]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for producing a stimulable phosphor in the solid-liquid state of stimulable phosphor particles or stimulable phosphor precursor particles present in a dispersion medium. In disintegrating aggregated particles generated during separation and drying, avoid mixing of impurities that adversely affect the stimulable phosphor characteristics, and disintegrate stimulable phosphor particles or stimulable particles at a high yield. An object of the present invention is to provide a technique for obtaining phosphor precursor particles.

[0026]

SUMMARY OF THE INVENTION The object of the present invention is to provide: (1) an agglomerated particle produced in a solid-liquid separation or drying process from a particle suspension in the presence of a rotating crushing blade in a moving vessel; A method for producing a phosphor that is disintegrated without using a pulverizing medium, 2 while disintegrating aggregated particles generated in the solid-liquid separation or drying process from the particle suspension and mixing particles different from the aggregated particles, A phosphor production method for crushing and mixing the different kinds of particles without using a crushing medium in the presence of a crushing blade rotating in a moving vessel; The method for producing a phosphor according to 1 or 2, which is an aggregated particle or a phosphor aggregated particle after firing, 4. The aggregated particle is a phosphor precursor aggregated particle before main firing, and the heterogeneous particle is a metal oxide. 3. The method for producing a phosphor according to item 2, wherein 5. The method for producing a phosphor according to any one of 1 to 4, wherein the aggregated particles comprise rare earth-activated alkaline earth metal fluorohalide-based stimulable phosphor precursor particles represented by the general formula (1). 6. The fluorescence according to 1, wherein the aggregated particles are composed of rare earth activated alkaline earth metal fluorohalide-based stimulable phosphor particles represented by the general formula (1) coated with a metal oxide and a silane coupling agent. Body manufacturing method, 7 Variation of mixed amount of metal oxide is ± 5
%, Wherein the peripheral speed of rotation of the crushing blade is 8 m / sec or more.
5. The method for producing a phosphor according to any one of items 4 to 9, 9 wherein the peripheral speed of rotation of the crushing blade is 10 m / sec or more.
5. The method for producing a phosphor according to any one of the above items 4 to 4.

[0027]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, crushing without using a crushing medium in the presence of a crushing blade rotating in a moving vessel for agglomerates means, for example, a multi-blender mill (Nippon Seiki Co., Ltd.). Using a device equipped with a rotating crushing blade in a moving container such as a rocking mixer (manufactured by Aichi Electric Co., Ltd.) or a rocking mixer (Aichi Electric Co., Ltd.), the aggregated particles are reduced to a moderately sized lump. This is performed without using a pulverizing medium such as a ball. Alternatively, it is in the state of primary particles.

Mixing with crushing means that the aggregated particles are reduced to an appropriately sized mass by the same apparatus and method. Alternatively, other particles different from the aggregated particles may be mixed at the same time as the primary particles.

When crushing is performed without using a crushing medium, the peripheral speed of the crushing blade is 5 m / sec or more, preferably 5 m / sec or more, more preferably 8 m / sec or more.
It is more preferably at least 10 m / sec.

When crushing and mixing of different kinds of particles are performed simultaneously without using a crushing medium, the peripheral speed of the crushing blade is 8 m / sec.
c or more, preferably 10 m / sec or more, more preferably 15 m / sec or more.

Although the air serves as a cushion, the particles are not destroyed even if the peripheral speed is increased, but a practical device is used.
The upper limit is about 0 m / sec.

Next, the term "aggregated particles are phosphor precursor aggregated particles before firing or phosphor particles after firing" means that the phosphor precursor is used to impart photostimulable luminescent properties to the stimulable phosphor. Of the firing at a high temperature, the firing process that reaches the highest temperature is defined as the main firing, and includes the phosphor precursor sintered during the preliminary firing performed prior to this firing.

The aggregated particles generated during the solid-liquid separation or drying process from the particle suspension are the same as the phosphor particles after firing.
Aggregation that occurs when the phosphor particles after the main baking are added to a solvent and then taken out as solid particles again.

Next, a metal oxide different from the aggregated particles according to the present invention will be described. The metal oxide different from the aggregated particles, which is preferably used in the present invention, is a sintering inhibitor for preventing sintering at the time of firing, specifically, MgO, C
aO, Al ₂ O ₃ , SiO ₂ , TiO ₂ , ZrO ₂ , Ta ₂ O
_{3 and the} like.

Next, as a specific example of the rare earth activated alkaline earth metal fluorinated halide based stimulable phosphor precursor represented by the general formula (1) preferably used in the present invention, BaFI: 0.005 Eu BaFI: 0.001 Eu Ba _0.97 Sr _0.03 FI: 0.001 K, 0.013 Eu BaFI: _0.002 K, 0.005 Eu Ba _0.998 Ca _0.002 FI: 0.005 Eu BaFI: 0.005 Ce Ba _0.99 Ca _0.01 FI: 0.001 K , 0.005EuBaFI: 0.001Ce, 0.0001Tb, but the present invention is not limited to these.

In the present invention, it is preferable that aggregation particles of the precursor of the stimulable phosphor be coated with a metal oxide and a silane coupling agent to suppress deliquescence. To metal oxide (hereinafter, metal oxide (1))
And (B) after firing the precursor of the stimulable phosphor in the presence of the metal oxide (1),
After coating with a silane coupling agent and firing the precursor of the stimulable phosphor in the presence of the metal oxide (1), the silane coupling agent and the following metal oxide (hereinafter referred to as metal oxide (2)) ).

Hereinafter, these methods will be described. Regarding the method (A) The coating treatment with the metal oxide particles has a great effect particularly on the metal oxide particles subjected to the hydrophobic treatment.

However, by treating the stimulable phosphor with the metal oxide particles and then treating with the silane coupling agent, the same effect can be given to the metal oxide fine particles.

Regarding the treatment for preventing deterioration of the stimulable phosphor,
Although a silane coupling agent is effective, it has been difficult to directly form a silicon-containing coating with the stimulable phosphor particles and the silane coupling agent on the stimulable phosphor particles.

Since the coating treatment with the particles of the metal oxide (2) and the surface treatment with the silane coupling agent are performed, the silicon-containing coating with the silane coupling agent is dispersed on the stimulable phosphor particles. It is believed that the silane coupling agent functions to form a continuous phase to fill in the surroundings.

It is effective to carry out the coating with the metal oxide (2) particles and the surface treatment with the silane coupling agent at the same time, or to carry out the surface treatment with the silane coupling agent after coating the metal oxide particles. .

The metal oxide (2) particles preferably used in the present invention are composed of one or more of silica, alumina and titanium oxide, and preferably have a particle size of 2 to 50 nm. If the particle size is less than 2 nm, it is difficult to obtain a commercial product, and if it exceeds 50 nm, it is difficult to coat the surface of the stimulable phosphor particles satisfactorily.

Examples of the particles of the metal oxide (2) include dry metal oxides such as silica, alumina and titanium dioxide by flame hydrolysis and arc methods, and acid salts such as sodium silicate. Examples thereof include those obtained by various production methods, such as a wet-process metal oxide obtained by decomposition by a method, and a method obtained by hydrolysis of an organogel.

Examples of the method of hydrophobizing metal oxide particles include a treatment with a silane coupling agent such as dimethylchlorosilane, hexamethyldisilane, octyltrimethoxysilane, and a treatment with silicon oil. Commercially available metal oxide particles that have already been subjected to a hydrophobic treatment are also available. Here, the hydrophobized metal oxide particles refer to particles having a degree of hydrophobization (MW value) of greater than 20 according to a methanol wettability method.

To mix an appropriate amount of metal oxide with stimulable phosphor particles having an average particle size of several μm to several tens μm, any ordinary method can be used. Car mixer (Shinmaru Enterprises)
A method in which the stimulable phosphor particles are gradually added to the total amount of the metal oxide by using a mixing device such as
A method of stirring the stimulable phosphor particles in a metal oxide dispersion having a concentration of 0.0% by mass and then drying the stimulable phosphor particles is preferred from the viewpoint of uniform coating of the particles.

The silane coupling agent preferably used in the present invention will be described. The silane coupling agent for coating the aggregated particles of the rare earth-activated alkaline earth metal fluorohalide stimulable phosphor precursor represented by the general formula (1) of the present invention is represented by the following general formula (2). Are preferred.

[0047]

Embedded image

In the formula, R represents an aliphatic or aromatic hydrocarbon group, which may include an unsaturated group (for example, a vinyl group), R'OR "-, R'COOR"-, R 'NH
R "-(R 'is an alkyl group, an aryl group, R" is an alkylene group, an arylene group) and may be substituted with other substituents.

[0049] _{Further, X 1, X 2, X} 3 represents an aliphatic or aromatic hydrocarbon, an acyl group, an amide group, an alkoxy group, an alkylcarbonyl group, an epoxy group, a mercapto group or a halogen atom, X _1, X ₂ and X ₃ may be the same or different from each other. However, at least one is a group other than a hydrocarbon group. Preferably, X ₁ , X ₂ and X ₃ are groups that undergo hydrolysis.

Specific examples of these silane coupling agents include methyltrimethoxysilane, methyltriethoxysilane, vinyltriacetoxysilane, vinyltrichlorosilane, vinyltriethoxysilane, γ-chloropropyltrimethoxysilane, γ-chloropropylmethyl Dichlorosilane, γ-chloropropylmethyldimethoxysilane, γ-chloropropylmethyldiethoxysilane, γ-
Aminopropyltriethoxysilane, N- (β-aminoethyl) -γ-aminopropyltrimethoxysilane, N
-(Β-aminoethyl) -γ-aminopropylmethyldimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropylmethyldimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ
-Glycidoxypropylmethyldimethoxysilane, γ-
Methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, γ- (2
-Aminoethyl) aminopropyltrimethoxysilane,
γ-isocyanatopropyltriethoxysilane, γ-
(2-aminoethyl) aminopropylmethyldimethoxysilane, γ-anilinopropyltrimethoxysilane, vinyltrimethoxysilane, N-β- (N- (vinylbenzylaminoethyl) -γ-aminopropyltrimethoxysilane.hydrochloride And aminosilane compounds, among which vinyl, mercapto, glycid and methacryloxy are preferred, and mercapto is particularly preferred.

Particularly preferred silane couplings include γ-mercaptopropyltrimethoxysilane (described below), γ-mercaptopropylmethyldimethoxysilane (described below), mercaptopropyltriethoxysilane, and the like. These mercapto-based silane coupling agents 1-mercaptomethyl-1,1,3,3,3-pentamethyldisiloxane;
1- (3-mercaptopropyl) -1,1,3,3,3
-Pentamethyldisiloxane and the like.

[0052]

Embedded image

The compound containing a mercapto group has an effect of preventing discoloration of the stimulable phosphor, and is preferably used in the present invention. The effect of preventing a decrease in sensitivity due to coloring of the phosphor is also added.

The discoloration preventing effect of the compound containing a mercapto group is particularly remarkable when the stimulable phosphor contains iodine in the structure. Effectively prevent.

In attaching the silane coupling agent to the stimulable phosphor particles coated with the metal oxide particles, a known method can be used.

For example, using a Henschel mixer, a dry method in which a silane coupling agent is dropped or sprayed while stirring and mixing the stimulable phosphor particles, and stirring is performed while dropping the silane coupling agent to a slurry of the stimulable phosphor. After the dropping, the stimulable phosphor is precipitated and filtered, and then the stimulable phosphor is dried to remove the residual solvent. A slurry method, the stimulable phosphor is dispersed in a solvent, and a silane coupling agent is added thereto. Is added and stirred, and then the solvent is evaporated to form an adhesion layer, or a silane coupling agent is added to the stimulable phosphor coating dispersion.

Further, in order to ensure the reaction between the silane coupling agent and the stimulable phosphor, the reaction is carried out at 60 to 130 ° C. for 1 hour.
It is desirable to perform drying for about 0 to 200 minutes.

The effect of the present invention appears remarkably when coating with metal oxide particles and surface treatment with a silane coupling agent are performed simultaneously.

As an example of such a treatment method, the stimulable phosphor particles immediately after firing in a dispersion of metal oxide particles and a silane coupling agent are crushed into a liquid to form a stimulable phosphor. After coating with metal oxide particles and surface treatment with a silane coupling agent at the same time as crushing, a method of filtering and drying,
Examples include a method in which metal oxide particles and a silane coupling agent are added to a coating dispersion for a stimulable phosphor layer, but the method is not limited thereto.

In the present invention, if the amount of the metal oxide exceeds 10% by mass with respect to the stimulable phosphor, the sensitivity is lowered, and if the amount is less than 0.05% by mass, the effect of the present invention is reduced by half. . If the amount of the silane coupling agent is more than 5% by mass with respect to the amount of the stimulable phosphor, the sensitivity is lowered, the coating film is hardened, cracks are generated on the film surface, and the content is 0.1% by mass or less. And the effect of the present invention is halved.

Method (B) Next, the method (B) using a silane coupling agent will be described first.

When the precursor particles of the stimulable phosphor are coated with the particles of the metal oxide (1) before sintering, the sintering treatment is performed, and then the surface treatment is performed with a silane coupling agent. Even if the phosphor particles are obtained and applied as a stimulable phosphor layer on a support through dispersion, solution preparation, and coating steps, the effect of improving the moisture resistance of the particles is maintained.

It is considered that the stimulable phosphor particles and the metal oxide particles are bonded by an electric force, and when a force exceeding this electric force acts in the dispersion, liquid preparation, and coating steps, the metal oxide particles are decomposed. It is considered that peeling from the stimulable phosphor occurs. However, if a silane coupling agent is used in this method, peeling can be suppressed and a moisture resistance effect after application can be obtained.

In particular, the amount of the metal oxide (1) is determined within a range that does not impair the firing efficiency, and after the firing, the stimulable phosphor particles are coated with the insufficient amount of the metal oxide (2), By performing the treatment with the coupling agent, it is possible to suppress a decrease in the light emission characteristics due to a decrease in the firing efficiency.

It is unknown why the metal oxide particles do not peel off from the stimulable phosphor particles in the dispersion, liquid preparation, and coating steps. It is presumed that some kind of bonding occurs.

In the present invention, the metal oxide (1) is preferably alumina from the viewpoint of preventing the stimulable phosphor particles from sintering, and is 0 to the amount of the stimulable phosphor precursor in terms of firing efficiency. It is preferably used at 0.01 to 2.0% by mass.

When alumina is used as the metal oxide (1), particularly when silica is used as the metal oxide (2), the moisture resistance of the stimulable phosphor is further improved.
It is not clear why the moisture resistance is improved by silica, but it is presumed that since the charging characteristics are different from alumina, the alumina particles immobilized on the stimulable phosphor surface and strong electric force work. .

The particle size of the metal oxide particles is preferably 2 to 50 nm. If the particle size is less than 2 nm, it is difficult to obtain a commercial product, and if it exceeds 50 nm, it becomes difficult to coat the surface of the stimulable phosphor particles satisfactorily.

In the present invention, the variation in the mixing amount of the metal oxide is preferably ± 5% or less with respect to the theoretical amount.

The metal oxide used in the method (B) is also
It is the same as that used in the method (A), and the metal oxide (1) and the metal oxide (2) may be the same substance or different substances.

[0071]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.

Preparation of Stimulable Phosphor BaFI: 0.005 Eu <Synthesis of Stimulable Phosphor BaFI: 0.005 Eu Precursor> A stimulable phosphor precursor of europium-activated barium fluoroiodide is synthesized. For this purpose, a BaI ₂ aqueous solution (1.75M)
2500 ml and EuI ₃ aqueous solution (0.07 M) 125 m
was placed in a reactor, and the reaction mother liquor in the reactor was kept at 83 ° C. while stirring.

Aqueous solution of ammonium fluoride (8M) 250m
1 was added to the reaction mother liquor using a roller pump to form a precipitate, and after completion of the addition, the mixture was kept warm and stirred for 2 hours to ripen the precipitate.

Next, the precipitate was separated by filtration, the solid content was washed with ethanol, and dried under vacuum to obtain agglomerated particles of europium-activated barium fluoroiodide (hereinafter referred to as precursor-1).

Example 1 Multi-blender mill (BLA-5 manufactured by Nippon Seiki Seisaku-sho, Ltd.)
01), 0.15 g of alumina particles having an average particle diameter of 13 nm (Alumina C manufactured by Nippon Aerosil Co., Ltd.) and 150 g of the aggregated particles of the precursor-1 were charged, and the cutter was rotated at 6,000 rpm (peripheral speed: 18 m / sec). ), The precursor-1 was disintegrated and the precursor-1 was mixed with alumina particles at a cup rotation speed of 3 [scale] for 10 minutes.

Comparative Example 1 A 3-liter nylon pot was charged with alumina particles having an average particle diameter of 13 nm (Alumina C, manufactured by Nippon Aerosil Co., Ltd.) 0.15.
g and 150 g of aggregated particles of the precursor-1 and 25 g
5.0 kg of a ball made of alumina having a diameter of mmφ was charged, and the precursor-1 was placed in a vibration mill (MB-1 type, manufactured by Chuo Kakohki Co., Ltd.) for 1 hour.
And the mixing of precursor-1 and alumina particles.

Example 2 A multi-blender mill container was charged with alumina particles having an average particle diameter of 13 nm (Alumina C manufactured by Nippon Aerosil Co., Ltd.).
5 g and 150 g of the aggregated particles of the precursor-1 were charged,
Cutter rotation speed 4,000 rpm (peripheral speed 12 m / sec
c) Crushing of precursor-1 and mixing of precursor-1 and alumina particles were performed at a cup rotation speed of 3 [scale] for 10 min.

<Quantitative Determination of Al Mixing Amount> The mixture of the precursor-1 and the alumina particles obtained in Example 1, Comparative Example 1 and Example 2 was mixed at the upper center, lower center, upper wall, and lower wall of each container. 1 g each was sampled, and quantitative analysis of the amount of Al was performed by the following method.

First, 500 g of a mixture of precursor-1 and alumina particles is precisely weighed in a Teflon (registered trademark) beaker, and 10 ml of concentrated hydrochloric acid (electronics grade) is added.

Next, heating on a hot plate, boiling and melting,
After drying, hydrochloric acid is added again, and the mixture is dissolved by boiling to dryness.

Finally, 5 ml of hydrochloric acid and 10 ml of ultrapure water are added and dissolved by heating, and the volume is adjusted to 50 ml.

This solution was treated with a plasma emission spectrometer (SPS4000, manufactured by Seiko Denshi Kogyo KK).
6. Measure the intensity of the emission line at 15 nm and use the calibration curve to
The amount of l was determined.

Table 1 shows the Al quantification results (measured amount-theoretical amount).
/ Theoretical quantity × 100.

[0084]

[Table 1]

From Table 1, it can be seen that the mixture of precursor-1 and alumina particles obtained according to the example of the present invention was more uniformly mixed than the mixture of precursor-1 and alumina particles obtained in the comparative example. Can be confirmed.

Example 3 <Firing of stimulable phosphor precursor> A mixture of the precursor-1 obtained in Example 1 and alumina particles was charged into a quartz boat, and the mixture was placed in a hydrogen gas atmosphere using a tube furnace. 850 ° C
For 2 hours to obtain europium-activated barium fluoroiodide phosphor particles (hereinafter referred to as fired phosphor-1).

A mixture of precursor-1 and alumina particles obtained in Comparative Example 1 was treated in the same manner as fired phosphor-1 to produce europium-activated barium fluoroiodide phosphor particles (hereinafter fired phosphor-2). ).

A mixture of precursor-1 and alumina particles obtained in Example 2 was treated in the same manner as fired phosphor-1 to obtain europium-activated barium fluoroiodide phosphor particles (hereinafter fired phosphor-3). ).

Table 2 shows the results of visual evaluation of the shapes of the fired phosphors 1 to 3 obtained. In addition, the fired phosphor
The lump of No. 3 can be easily crushed with a fingertip, but the lump of the fired phosphor-2 was strongly sintered.

[0090]

[Table 2]

Thus, the uniformity of the alumina particles was set to ± 5%.
It was confirmed that sintering during firing can be prevented by the following.

<Hydrophobic treatment of stimulable phosphor> Hydrophobic silica particles having an average particle diameter of 7 nm (R97 manufactured by Nippon Aerosil Co., Ltd.)
6) 15 g, silane coupling agent (SH6062SILANE manufactured by Dow Corning Toray Silicone Co., Ltd.) 40
g, 20 g of water and 1,425 g of ethanol in a container,
While keeping the temperature at 45 ° C, TK ROBO MICS
Hydrophobic silica was dispersed in ethanol using (manufactured by Tokushu Kika Kogyo KK).

Then, the fired phosphor-1 was added to the stirred suspension of hydrophobic silica containing the silane coupling agent.
Was added and dispersed for further 4 hours.

The europium-activated barium fluoroiodide phosphor suspension was subjected to solid-liquid separation by filtration under pressure.
By drying for 5 hours, hydrophobized europium-activated barium fluoroiodide phosphor aggregated particles (hereinafter referred to as hydrophobized phosphor-1) were obtained.

In a container of a multi-blender mill BLA-2001, 1.0 kg of the above-mentioned hydrophobized phosphor-1 was put, and the cutter rotation speed was 3,000 rpm (peripheral speed 11 m / s).
ec) By operating at a cup rotation speed of 3 [scale] for 10 minutes, 0.99 kg of the crushed particles of the hydrophobicized phosphor-1 (hereinafter referred to as crushed phosphor-1) was obtained. Was.

Comparative Example 2 1.0 kg of the hydrophobized phosphor-1 and a 25 mmφ alumina ball were placed in a 3-liter nylon pot.
Add 0kg, shake mill (MB-1 manufactured by Chuo Kakoki Co., Ltd.)
Then, 0.85 kg of the crushed particles of the above-mentioned hydrophobic treated phosphor-1 (hereinafter referred to as crushed phosphor-2) was obtained by crushing for 1 hour using a mold.

It should be noted that a large amount of the hydrophobicized phosphor was attached to the alumina balls used for the crushing and the stainless steel mesh used for separating the crushed particles from the alumina balls. This led to a decrease in the yield of the disintegrated phosphor-2.

Example 4 Into a container of a multi-blender mill BLA-2001, 1.0 kg of the hydrophobized phosphor-1 was put, and the number of rotations of a cutter was 2,000 rpm (peripheral speed: 7.3 m / sec); By operating at 3 [scale] for 10 minutes, the crushed particles of the hydrophobic treated phosphor-1 (hereinafter, referred to as “particles”).
0.99 kg).

<Fiter Suitability of Disintegrated Phosphor> The above-mentioned hydrophobized phosphor-1, disintegrated phosphor-1, -2 and -3 are manufactured by Kuma Engineering Co., Ltd., Accurate Model 102 type. Table 3 shows the results of visual evaluation of feeder suitability using a feeder.

[0100]

[Table 3]

As shown in Table 3, the non-crushed hydrophobicized phosphor-1 was clogged in the hopper and could not be fed, and the crushed fluorescent light with a low peripheral speed of the crushing blade was used. Body-3 is the amount (speed) of phosphor discharged from the feeder outlet
Was unstable.

Further, the disintegrated phosphor-2 could be stably supplied (discharged) similarly to the disintegrated phosphor-1 of the embodiment, but the yield after disintegration was as described above. Is very low.

[0103]

According to the present invention, the stimulable phosphor particles or the stimulable phosphor precursor particles existing in the dispersion medium are disintegrated in solid-liquid separation and agglomerated particles produced during drying. It is possible to avoid mixing impurities that adversely affect the physical properties, and to obtain crushed stimulable phosphor particles or stimulable phosphor precursor particles at a high yield.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C09K 11/61 CPF C09K 11/61 CPF (72) Inventor Takehiko Shoko 1 Sakuracho, Hino-shi, Tokyo Konica shares In-house F term (reference) 4H001 CA04 CA08 CC02 CC11 CF01 CF02 XA09 XA12 XA17 XA20 XA30 XA35 XA38 XA48 XA53 XA56 YA03 YA11 YA19 YA37 YA55 YA58 YA59 YA60 YA62 YA63 YA64 YA65 YA66 YA67

Claims (9)

[Claims] The present invention is characterized in that agglomerated particles generated in a solid-liquid separation or drying process from a particle suspension are crushed without using a crushing medium in the presence of a crushing blade rotating in a moving vessel. Phosphor manufacturing method. 2. A crushing blade that rotates in a moving vessel for crushing aggregated particles generated in a solid-liquid separation or drying process from a particle suspension and mixing particles different from the aggregated particles. A method for producing a phosphor, comprising performing crushing and mixing of the different kinds of particles without using a crushing medium in the presence of a crushing medium. 3. The phosphor manufacturing method according to claim 1, wherein the aggregated particles are phosphor precursor aggregated particles before firing or phosphor aggregated particles after firing. 4. The method for producing a phosphor according to claim 2, wherein the aggregated particles are phosphor precursor aggregated particles before the main baking, and the heterogeneous particles are metal oxides. 5. The method according to claim 1, wherein the agglomerated particles comprise rare earth-activated alkaline earth metal fluorinated halide-based stimulable phosphor precursor particles represented by the following general formula (1). 5. The method for producing a phosphor according to any one of 4. General formula (1) Ba _1-x M ² _x FX: yM ¹ , zLn wherein M ² represents at least one kind of alkaline earth metal selected from the group consisting of Mg, Ca, Sr, Zn and Cd; M ¹ represents at least one alkali metal selected from the group consisting of Li, Na, K, Rb and Cs. X is C
l, Br and at least one halogen atom selected from the group consisting of I, Ln is Ce, Pr, Sm, Eu, G
It represents at least one rare earth element selected from the group consisting of d, Tb, Tm, Dy, Ho, Nd, Er and Yb. x, y and z are respectively 0 ≦ x ≦ 0.6 and 0 ≦ y
≦ 0.05, 0 <z ≦ 0.2. ] 6. An agglomerated particle comprising a rare earth-activated alkaline earth metal fluorohalide-based stimulable phosphor particle represented by the above general formula (1) coated with a metal oxide and a silane coupling agent. The method for producing a phosphor according to claim 1, wherein: 7. The method for producing a phosphor according to claim 4, wherein the variation of the mixing amount of the metal oxide is ± 5% or less with respect to the theoretical amount. 8. The phosphor manufacturing method according to claim 1, wherein a peripheral speed of rotation of the crushing blade is 8 m / sec or more. 9. The method for producing a phosphor according to claim 2, wherein a peripheral speed of rotation of the crushing blade is 10 m / sec or more.